Devices and methods for increasing blood perfusion to a distal extremity

Abstract

Abstract Devices and methods divert blood flow from a first vessel to a second vessel and maintain blood flow in the first vessel. The device includes a first segment and a second segment. The first segment is configured to anchor in the first vessel. The first segment includes a window to allow blood to flow into the first segment, through the window, and distal in the first vessel. The second segment is configured to anchor in the second vessel. The second segment is configured to allow blood to flow into the first segment, through the second segment, and into the second vessel. Abstract WO 2021 / 087294 85 / 101 PCT / US2020 / 058263 5101 5104 5102 5108 5107 5105 5103 5100 5112 5110 5106 5109 FIG. 51A 5124 5128 5127b 5125 5112 5101 5120 5127a 5102 5126 5129 5110 FIG. 51B 20 26 22 32 62 27 A ug 2 02 6 W O 2 0 2 1 / 0 8 7 2 9 4 8 5 / 1 0 1 P C T / U S 2 0 2 0 / 0 5 8 2 6 3 2 7 A u g 2 0 2 6 2 0 2 6 2 2 3 2 6 2 5 1 0 1 5 1 0 4 5 1 0 2 5 1 0 7 5 1 0 3 5 1 0 0 5 1 1 2 5 1 1 0 5 1 0 6 5 1 0 9 5 1 2 4 5 1 2 8 5 1 0 1 5 1 2 0 5 1 2 7 a 5 1 0 2 5 1 1 0

Description

[0403] The length of a stent, a stent-graft, or a first end portion, second end portion, intermediate portion, or subportion thereof may be between about 5 mm and about 150 mm, between about 5 mm and about 110 mm, between about 5 mm and about 70 mm, between about 5 mm and about 50 mm, between about 5 mm and about 25 mm, between about 5 mm and about 20 mm, between about 5 mm and about 10 mm, between about 10 mm 2026223262   27 Aug 2026 and about 150 mm, between about 10 mm and about 110 mm, between about 10 mm and about 70 mm, between about 10 mm and about 50 mm, between about 10 mm and about 25 mm, between about 10 mm and about 20 mm, between about 20 mm and about 150 mm, between about 20 mm and about 110 mm, between about 20 mm and about 70 mm, between about 20 mm and about 50 mm, between about 20 mm and about 25 mm, between about 25 mm and about 150 mm, between about 25 mm and about 110 mm, between about 25 mm and about 70 mm, between about 25 mm and about 50 mm, between about 50 mm and about 150 mm, between about 50 mm and about 110 mm, between about 50 mm and about 70 mm, between about 70 mm and about 150 mm, between about 70 mm and about 110 mm, or between about 110 mm and about 150 mm. Other lengths are also possible, including lengths greater than or less than the identified lengths.

[0404] The porosity of a stent, a stent-graft, or a first end portion, second end portion, intermediate portion, or subportion thereof may be between about 5% and about 95%, between about 5% and about 50%, between about 5% and about 25%, between about 5% and about 10%, between about 10% and about 50%, between about 10% and about 25%, between about 25% and about 50%, between about 50% and about 95%, between about 50% and about 75%, between about 50% and about 60%, between about 60% and about 95%, between about 75% and about 90%, between about 60% and about 75%, and combinations thereof The density of a stent may be inverse to the porosity7 of that stent. The porosity of a portion of a stent covered by a graft may be about 0%. The porosity may vary by objectives for certain portions of the stent. For example, the intermediate portion may have a low porosity to increase fluid flow through the device, while end portions may have lower porosity to increase flexibility and wall apposition.

[0405] Figure 25A is a schematic side elevational view of yet another example embodiment of a prosthesis 500. The prosthesis or stent or device 500 includes and / or consist essentially of a plurality of filaments 502 woven together into a woven structure. The stent 500 may be devoid of graft material, as described in further detail below.

[0406] The filaments 502, which may also be described as wires, ribbons, strands, and the like, may be woven, braided, layered, or otherwise arranged in a crossing fashion. The filaments 502 are generally7 elongate and have a circular, oval, square, rectangular, etc. transverse cross-section. Example non-woven filaments can include a first layer of filaments 2026223262   27 Aug 2026 wound in a first direction and a second layer of filaments wound in a second direction, at least some of the filament ends being coupled together (e.g., by being coupled to an expandable ring). Example weave patterns include one-over-one-under-one (e.g., as shown in Figure 25A), a one-over-two-under-two, a two-over-two-under-two, and / or combinations thereof, although other weave patterns are also possible. At crossings of the filaments 502, the filaments 502 may be helically wrapped, cross in sliding relation, and / or combinations thereof. The filaments 502 may be loose (e.g., held together by the weave) and / or include welds, coupling elements such as sleeves, and / or combinations thereof. Ends of filaments 502 can be bent back, crimped (e.g., end crimp with a radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc. that can also act as a radiopaque marker), twisted, ball 'welded, coupled to a ring, combinations thereof, and the like. Weave ends may include filament 502 ends and / or bent-back filaments 502, and may include open cells, fixed or unfixed filaments 502, welds, adhesives, or other means of fusion, radiopaque markers, combinations thereof, and the like.

[0407] The stent 500 includes pores 504 or open, non-covered areas between the filaments 502. The porosity of the stent 500 may be computed as the outer surface area of the pores 504 divided by the total outer surface area of the stent 500. The porosity may be affected by parameters such as, for example, the number of filaments 502, the braid angle 506, the size (e.g., diameter) of the filaments 502, and combinations thereof.

[0408] The porosity of the stent 500 may be less than about 50% (e.g., slightly more covered than open), between about 0% (e.g., almost no open area) and about 50%, between about 0% and about 45%, between about 0% and about 40%, between about 0% and about 35%, between about 0% and about 30%, between about 0% and about 25%, between about 0% and about 20%, between about 0% and about 15%, between about 0% and about 10%, between about 0% and about 5%, between about 5% and about 50%, between about 5% and about 45%, between about 5% and about 40%, between about 5% and about 35%, between about 5% and about 30%, between about 5% and about 25%, between about 5% and about 20%, between about 5% and about 15%, between about 5% and about 10%, between about 10% and about 50%, between about 10% and about 45%, between about 10% and about 40%, between about 10% and about 35%, between about 10% and about 30%, between about 10% and about 25%, between about 10% and about 20%, between about 10% and 2026223262   27 Aug 2026 about 15%, between about 15% and about 50%, between about 15% and about 45%, between about 15% and about 40%, between about 15% and about 35%, between about 15% and about 35%, between about 15% and about 25%, between about 15% and about 20%, between about 20% and about 50%, between about 20% and about 45%, between about 20% and about 40%, between about 20% and about 35%, between about 20% and about 35%, between about 20% and about 25%, between about 25% and about 50%, between about 25% and about 45%, between about 25% and about 40%, between about 25% and about 35%, between about 25% and about 35%, between about 30% and about 50%, between about 30% and about 45%, between about 30% and about 40%, between about 30% and about 35%, between about 35% and about 50%, between about 35% and about 45%, between about 35% and about 40%, between about 40% and about 50%, between about 40% and about 45%, between about 45% and about 50%, and combinations thereof.

[0409] In some embodiments in which the porosity is less than about 50%, blood may be unable to perfuse through the sidewalls of the stent 500 under normal vascular pressures (e.g., a pressure drop across a vessel, a pressure drop from an afferent vessel to an efferent vessel). In certain such embodiments, blood flowing into a proximal end of the stent 500 can be directed through a lumen of the stent 500 to a distal end of the stent 500 without (e.g., substantially without, free of, substantially free of) graft material, but still without loss or substantial loss of blood through the sidewalls of the stent 500. By contrast, in certain so-called “flow diverting stents,” the porosity is specifically designed to be greater than about 50% in order to ensure perfusion to efferent vessels,

[0410] The density of the stent 500 may be inverse to the porosity (e.g., the outer surface area of the filaments 502 divided by the total outer surface area of the stent 500). The density of the stent 500 may be 100% minus the porosity values provided above.

[0411] The filaments 502 are at a braid angle 506 relative to an axis perpendicular to the longitudinal axis of the stent 500 (e.g., as illustrated by the example dashed line in Figure 25A). The braid angle 506 can range from just more than 90° to just under 180°. The braid angle 506 can be acute or obtuse. In some embodiments, the braid angle 506 is between about 90° and about 180°, between about 120° and about 180°, between about 150° and about 180°, between about 160° and about 180°, between about 170° and about 180°, between about 160° and about 170°, between about 165° and about 175°, combinations 2026223262   27 Aug 2026 thereof, and the like. In some embodiments, the closer the braid angle 506 is to 180°, the greater the radial strength of the stent 500. Devices 500 with greater radial strength may aid in keeping a fistula (e.g., formed as described herein) open or patent. Other factors can also influence radial strength such as filament 502 diameter, filament 502 material, number of filaments 502, etc.

[0412] The filaments 502 may all be the same or some of the filaments 502 may have a different parameter (e.g., material, dimensions, combinations thereof, and the like). In some embodiments, some of the filaments 502 comprise shape memory material (e.g., comprising nitinol) and others of the filaments 502 comprise another material (e.g., comprising aramid fiber (e.g., Kevlar®'1), Dacron®, biocompatible polymer, etc.). The shape memory material may provide the mechanical structure and the other material may provide low porosity (e.g., by being thick in the dimension of the sidewalls).

[0413] Figure 25B is a schematic side elevational view of still yet another example embodiment of a prosthesis 520. The prosthesis or stent or device 520 includes and / or consist essentially of a first plurality' of filaments 522 woven together into a first woven structure and a second plurality of filaments 524 woven together into a second woven structure. The stent 520 may be devoid of graft material, as described in further detail herein. The first plurality of filaments 522 may be similar to the filaments 502 of the stent 500 described with respect to Figure 25A. In some embodiments, the filaments 522 may lack sufficient radial force to keep a fistula open and / or to appose sidewalls of an artery and / or a vein. In certain such embodiments, the filaments 524 may act as a supplemental support structure to provide the radial force. The filaments 524 may be radially outward of the filaments 522 (e.g., as illustrated in Figure 25B), radially inward of the filaments 522, and / or integrated with the filaments 522 (e.g., such that the first and second woven structures are not readily separable. The filaments 524 may be the same or different material as the filaments 522, the same or different thickness as the filaments 522, etc., and / or the filaments 524 maybe braided with the same or different parameters (e.g., braid angle) than the filaments 522, resulting in filaments 524 having greater radial force. The filaments 524 may be coupled to the filaments 522 (e.g., in a single deployable stent 520) or separately deployed. For example, if the filaments 524 are deployed and then the filaments 522 are deployed, the filaments 524 can prop open a fistula and allow' the filaments 522 to expand within the lumen 2026223262   27 Aug 2026 created by the filaments 524 without substantial opposing force. For another example, if the filaments 522 are deployed and then the filaments 524 are deployed, the filaments 524 can act as an expansion force on the portions of the filaments 522 in need of an expansive force.

[0414] .Although illustrated in Figure 25B as comprising a second woven structure, the supplemental support structure may additionally or alternatively comprise a helical coil, a cut hypotube, combinations thereof, and the like. Determination of the porosity of the prosthesis 520 may be primarily based on the porosity of the first woven structure such that the supplemental support structure may be designed primarily for providing radial force (e.g., sufficient to keep a fistula open or patent).

[0415] Although illustrated as being uniform or substantially uniform across the length of the stent 500, parameters of the stent 500 and the filaments 502 may vary across the stent 500, for example as described with respect to Figure 25C. Uniformity may reduce manufacturing costs, reduce a demand for precise placement, and / or have other advantages. Non-uniformity may allow specialization or customization for specific properties and / or functions along different lengths and / or have other advantages.

[0416] Figure 25C is a schematic side elevational view of still another example embodiment of a prosthesis 540. The prosthesis or stent or device 540 includes and / or consist essentially of a plurality7 of filaments 542 woven together into a woven structure. The stent 540 may be devoid of graft material, as described in further detail herein. The stent 540 comprises a first longitudinal section or segment or portion 544 and a second longitudinal section or segment or portion 546. Parameters such as porosity (e.g., as illustrated in Figure 25B), braid angle, braid type, filament 542 parameters (e.g., diameter, material, etc.), existence of a supplemental support structure (e.g,, the supplemental support, structure 544), stent diameter, stent shape (e.g., cylindrical, frustoconical), combinations thereof, and the like may be different between the first longitudinal section 544 and the second longitudinal section 546. The porosity may vary7 by objectives for certain portions of the stent 540. For example, the first longitudinal section 544, which may7 be configured for placement in an artery and a fistula, may have low porosity (e.g., less than about 50% as described with respect to the stent 500 of Figure 25 A) to increase fluid flow through the stent 500, while the second longitudinal section, which may be configured for placement in a vein, may have higher porosity to increase flexibility and wall apposition. 2026223262   27 Aug 2026

[0417] In some embodiments, a stent comprises a first longitudinal section comprising and / or consisting essentially of a low porosity weave configured to divert flow from an artery into a fistula and no supplemental support structure, a second longitudinal section comprising and / or consisting essentially of a low porosity weave configured to divert blood flow through a fistula and comprising a supplemental support structure configured to prop open the fistula, and a third longitudinal section comprising and / or consisting essentially of low porosity weave configured to divert flow from a fistula into a vein. In certain such embodiments, the first longitudinal section may be configured as the stent 500 of Figure 25A and the third longitudinal section may be configured as the stent 500 of Figure 25A or as the stent 540 of Figure 25C.

[0418] The difference between the first longitudinal section 544 and the second longitudinal section 546 may be imparted during manufacturing (e.g., due to braid parameters, shape setting, etc.) and / or in situ (e.g., during and / or after deployment (e.g., by stent packing)).

[0419] Other variations between the first longitudinal section 544 and the second longitudinal section 546 (e.g., including laser-cut portions, additional longitudinal sections, etc.), for example as described herein, are also possible. In some embodiments, a stent comprises a first longitudinal section comprising and / or consisting essentially of a low porosity weave configured to divert flow from an artery into a fistula, a second longitudinal section comprising and / or consisting essentially of a low porosity laser cut portion configured to be placed in a fistula, to divert blood through the fistula, and / or to prop open the fistula, and a third longitudinal section comprising and / or consisting essentially of low porosity weave configured to divert flow from a fistula into a vein. In certain such embodiments, the first longitudinal section may be configured as the stent 500 of Figure 25 A and the third longitudinal section may be configured as the stent 500 of Figure 25A. or as the stent 540 of Figure 25C.

[0420] Figure 27 schematically illustrates an example embodiment of a prosthesis 720, which is described with respect to the anatomy in Figure T1 in further detail below. The prosthesis 720 comprises a first longitudinal section 722, a second longitudinal section 724, and a third longitudinal section 726 between the first longitudinal section 722 and the second longitudinal section 724. The porosity of the prosthesis 720 may allow'’ the fluid to flow 2026223262   27 Aug 2026 substantially through the lumen of the prosthesis 720 substantially without perfusing through the sidewalls, even when substantially lacking graft material, for example due to a low porosity woven structure.

[0421] In embodiments in which the prosthesis 720 is used in peripheral vasculature, the first longitudinal section 722 may be described as an arterial section, the second longitudinal section 724 may be described as a venous section, and the third longitudinal section 726 may be described as a transition section. The first longitudinal section 722 is configured to appose sidewalls of an artery 700 or another cavity. For example, for some peripheral arteries, the first longitudinal section 722 may have an expanded diameter between about 2 mm and about 4 mm (e.g., about 3 mm). The second longitudinal section 724 is configured to appose sidewalls of a vein 702 or another cavity. For example, for some peripheral veins, the second longitudinal section 724 may have an expanded diameter between about 5 mm and about 7 mm (e.g., about 6 mm). In some embodiments, rather than being substantially cylindrical as illustrated in Figure 27, the second longitudinal section 724 and the third longitudinal section 726 may have a shape comprising frustoconical, tapering from the smaller diameter of the first longitudinal section 722 to a larger diameter.

[0422] The length of the prosthesis 720 may be configured or sized to anchor the prosthesis 720 in the artery' 700 and / or the vein 702 (e.g., enough to inhibit or prevent longitudinal movement or migration of the prosthesis 720) and to span the interstitial tissue T between the artery 700 and the vein 702, For example, for some peripheral arteries, the length of the first longitudinal section 722 in the expanded or deployed state may be between about 20 mm and about 40 mm (e.g., about 30 mm). For another example, for some peripheral veins, the length of the second longitudinal section 724 in the expanded or deployed state may be between about 10 mm and about 30 mm (e.g., about 20 mm). For yet another example, for some peripheral vasculature, the length of the third longitudinal section 726 in the expanded or deployed state may be between about 5 mm and about 15 mm (e.g., about 10 mm). The total length of the prosthesis 720 in the expanded or in a deployed state may be between about 30 mm and about 100 mm, between about 45 mm and about 75 mm (e.g., about 60 mm). The interstitial tissue T is illustrated as being about 2 mm thick, although other dimensions are possible depending on the specific anatomy of the deployment 2026223262   27 Aug 2026 site. Other dimensions of the prosthesis 720, the first longitudinal section 722 and / or the second longitudinal section 724, for example as described herein, are also possible.

[0423] The third longitudinal section 726 comprises a frustoconical or tapered shape, expanding from the smaller diameter of the first longitudinal section 722 to the second longitudinal section 724. Transition points between the longitudinal sections 722, 724, 726 may be distinct or indistinct. For example, the transition section may be said to include a portion of the first longitudinal section 722 and the third longitudinal section 726, or the third longitudinal section 726 may be said to include a cylindrical portion having the same diameter as the first longitudinal section 722. The longitudinal sections 722, 724, 726 may differ in shape and dimensions as described above, and / or in other ways (e.g., materials, pattern, etc.). For example, one or more portions may be cylindrical, frustoconical, etc., as illustrated in Figures 12, 13, and 27 and described herein.

[0424] The first longitudinal section 722 and / or the third longitudinal section 726 may comprise a relatively high radial force, for example configured to keep a fistula patent, and the second longitudinal section 724 may comprise a relatively low radial force. In some embodiments, the first longitudinal section 722 and / or the third longitudinal section 726 comprise a balloon-expandable stent, a woven stent with a high braid angle, and / or the like. In some embodiments, the second longitudinal section 724 comprises a self-expanding stent, a woven stent with a low braid angle, and / or the like. Combinations of laser-cut stents, woven stents, different cut patterns, different weave patterns, and the like are described in further detail herein. In some embodiments, the longitudinal sections 722, 724, 726 may be integral or separate. The second longitudinal section 724 may be relatively flexible, for example comprising relatively low radial force, which may help the second longitudinal section 724 flex with the anatomy during pulses of blood flow.

[0425] In some embodiments, the second longitudinal section 724 and / or the third longitudinal section 726 may comprise some graft material (e.g., comprising silicone). The graft material may inhibit or prevent flow through sidewalls of the prosthesis 720 and / or may be used to carry medicaments. For example, graft material may or may not occlude or substantially occlude the pores of the portions of the prosthesis 720 depending on the purpose of the graft material. 2026223262   27 Aug 2026

[0426] The proximal and / or distal ends of the prosthesis 720 may be atraumatic, for example comprising an end treatment, low braid angle, small filament diameter, combinations thereof, and the like.

[0427] The radial strength or compression resistance of a stent, a stent-graft, or a first end portion, second end portion, intermediate portion, or subportion thereof may be between about 0.1 N / mm and about 0.5 N / mm, between about 0.2 N / mm and about 0.5 N / mm, between about 0.3 N / mm and about 0.5 N / mm, between about 0.1 N / mm and about 0.3 N / mm, between about 0.1 N / mm and about 0.2 N / mm, between about 0.2 N / mm and about 0.5 N / mm, between about 0.2 N / mm and about 0.3 N / mm, or between about 0.3 N / mm and about 0.5 N / mm.

[0428] The values of certain parameters of a stent, a stent-graft, or a first end portion, second end portion, intermediate portion, or subportion thereof may be linked (e.g., proportional). For example, a ratio of a thickness of a strut or filament to a diameter of a device portion comprising that strut or filament may be between about 1:10 and about 1:250, between about 1:25 and about 1:175, or between about 1:50 and about 1:100. For another example, a ratio of a length of a device or portion thereof to a diameter of a device or a portion thereof may be between about 1:1 and about 50:1, between about 5:1 and about 25:1, or between about 10:1 and about 20:1.

[0429] Portions of the device may include radiopaque material. For example, filaments and / or struts a stent, a stent-graft, or a first end portion, second end portion, intermediate portion, or subportion thereof may comprise (e.g., be at least partially made from) titanium, tantalum, rhenium, bismuth, silver, gold, platinum, indium, tungsten, combinations thereof) and the like. For another example, filaments and / or struts of a stent, stent-graft, or a portion thereof may comprise (e.g., be at least partially made from) a material having a density greater than about 9 grams per cubic centimeter. Separate radiopaque markers may be attached to certain parts of the device. For example, radiopaque markers can be added to the proximal end of the device or parts thereof (e.g., a proximal part of the intermediate portion, a proximal part of the distal portion), the distal end of the device or parts thereof (e.g., a distal part of the intermediate portion, a distal part of the proximal portion), and / or other parts. A radiopaque marker between ends of a device may be useful, for example, to demarcate transitions between materials, portions, etc. Radiopacity may vary 2026223262   27 Aug 2026 across the length of the device. For example, the proximal portion could have a first radiopacity (e.g., due to distal portion material and / or separate markers) and the distal portion could have a second radiopacity (e.g., due to distal portion material and / or separate markers) different than the first radiopacity. Inflatable members such as balloons may be filled with radiopaque fluid. Inflatable members such as balloons may comprise a radiopaque marker coupled and / or integrated thereto (e.g., on an outer surface of the inflatable member).

[0430] In some embodiments, the device includes a polymer tube, and no supporting structure is provided. The intermediate portion of such a device may be relatively more flexible than the end portions by, for example, decreasing the wall thickness of the polymer tube within the intermediate portion.

[0431] When a mesh or other supporting structure is provided in combination with a polymer tube, the supporting structure may be located around the outside of the tube, in the inner bore of the tube, or embedded within a wall of the tube. More than one supporting structure may be provided, in which case each supporting structure may have a different location with respect to the tube.

[0432] One or both of the end portions of the device may include anchoring elements such as hooks, protuberances, or barbs configured to grasp or grip inner sidewalls of a blood vessel. The radial force of the end portions after expansion may be sufficient to grasp or grip inner sidewalls of a blood vessel without anchoring elements.

[0433] There need not be a well-defined transition between the intermediate and end portions. For example, mesh type, material, wall thickness, flexibility, etc. may gradually change from an end portion toward an intermediate portion or from an intermediate portion toward an end portion.

[0434] The flexibility of the device may increase gradually when moving from an end portion towards the intermediate portion, for example as described with respect to the devices 134, 140. The change in flexibility may be due to change in mesh density (e.g., winding density, window size), tube thickness, or other factors. The flexibility of the device may be uniform or substantially uniform along the entire length of the support structure (e.g., stent), or along certain portions of the support structure (e.g., along an entire end portion, along the entire intermediate portion, along one end portion and the intermediate portion but not the other end portion, etc.). 2026223262   27 Aug 2026

[0435] While the devices described herein may be particularly suitable for use as a transvascular shunt in percutaneous surgery, the devices could be used in many other medical applications. For example, the devices could be used in angioplasty for the treatment of occluded blood vessels with tortuous or kinked paths, or where the vessels may be subject to deflection or deformation at or near the position of the stent. The stent could also be used for the repair of damaged blood vessels, for example in aortic grafting procedures or after perforation during a percutaneous procedure. In certain such cases, the intermediate portion of the device can allow the device to conform to the shape of the blood vessel and to deform in response to movement of the vessel with reduced risk of fatigue failure while remaining fixed or anchored in position by the end portions. For another example, the devices could be used to form a shunt between a healthy artery’ and a healthy vein for dialysis access and / or access for administration of medications (e.g., intermittent injection of cancer therapy, which can damage vessels).

[0436] Referring again to Figures 4 and 7, blocking material 251 may be used to help inhibit or prevent reversal of arterial blood flow. As will now be described in further detail, additional or other methods and systems can be used to inhibit or prevent reversal of arterial blood flow, or, stated another way, to inhibit or prevent flow of arterial blood now flowing into the vein from flowing in the normal, pre-procedure direction of blood flow in the vein such that oxygenated blood bypasses downstream tissue such as the foot.

[0437] In the absence of treatment, Peripheral Vascular Disease (PAT)) may progress to critical limb ischemia (CLI), which is characterized by profound chronic pain and extensive tissue loss that restricts revascularization options and frequently leads to amputation. CLI is estimated to have an incidence of approximately 50 to 100 per 100,000 per year, and is associated with mortality rates as high as 20% at 6 months after onset,

[0438] Interventional radiologists have been aggressively trying to treat CLI by attempting to open up chronic total occlusions (CTOs) or bypassing CTOs in the sub-intimal space using such products as the Medtronic Pioneer catheter, which tunnels a wire into the sub-mtimal space proximal to the CTO and then attempts to re-enter the vessel distal to the occlusion. Once a wire is in place, a user can optionally create a wider channel and then place a stent to provide a bypass conduit past the occlusion. Conventional approaches such as percutaneous transluminal angioplasty (PTA), stenting, and drug eluting balloons (DEB) to 2026223262   27 Aug 2026 treat PAD can also or alternatively be used in CLI treatment if a wire is able to traverse the occlusion.

[0439] From the amputee-coalition.org website, the following are some statistics regarding the CLI problem: ® There are nearly 2 million people living with limb loss in the United States. ® Among those living with limb loss, the mam causes are: o vascular disease (54%) (including diabetes and peripheral artery disease (PAD)), o trauma (45%), and o cancer (less than 2%). • Approximately 185,000 amputations occur in the United States each year. • Hospital costs associated with having a limb amputated totaled more than $6.5 billion in 2007. ® Survival rates after an amputation vary based on a variety of factors. Those who have amputations due to vascular disease (including PAD and diabetes) face a 30-day mortality rate reported to be between 9% and 15% and a long-term survival rate of 60% at 1 year, 42% at 3 years, and 35%-45% at 5 years. ® Nearly half of the people who lose a limb to dysvascular disease will die within 5 years. This is higher than the 5-year mortality rate experienced by people with colorectal, breast, and prostate cancer. • Of people with diabetes who have a lower-limb amputation, up to 55% will require amputation of the second leg within 2 to 3 years.

[0440] CLI has been surgically treated by open-leg venous arterialization since the early 1900’s. Numerous small senes of clinical trials have been published over the years using such an open-leg surgical approach, as summarized by a 2006 meta-analysis article by Lu et al. in the European Journal of Vascular and Endovascular Surgery, vol. 31, pp. 493499, titled “Meta-analysis of the clinical effectiveness of venous arterialization for salvage of critically ischemic limbs.” The article had the following results and conclusions: ® Results: o A total of 56 studies were selected for comprehensive review. No randomized control trial (RCT) was identified. Seven patient series, comprising 228 2026223262   27 Aug 2026 patients, matched the seiection criteria. Overall 1-year foot preservation was 71% (95% CI: 64%-77%) and 1-year secondary patency was 46% (95% CI: 39%-53%). The large majority of patients in whom major amputation was avoided experienced successful wound healing, disappearance of rest pain, and absence of serious complications. ® Conclusions: o On the basis of limited evidence, venous arterialization may be considered as a viable alternative before major amputation is undertaken in patients with “inoperable” chronic critical leg ischemia.

[0441] Among other maladies as described herein, the methods and systems described herein may be used to create an aterio-venous (AV) fistula in the below-the-knee (BTK) vascular system using an endovascular, minimally invasive approach. Such methods may be appropriate for patients that (i) have a clinical diagnosis of symptomatic critical limb ischemia as defined by Rutherford 5 or 6 (severe ischemic ulcers or frank gangrene); (ii) have been assessed by a vascular surgeon and interventionist and it was determined that no surgical or endovascular treatment is possible; and / or (iii) are clearly indicated for major amputation.

[0442] In some embodiments, a system or kit optionally comprises one or more of the following components: a first ultrasound catheter (e.g., an arterial catheter, a launching catheter including a needle, etc.); a second ultrasound catheter (e.g., a venous catheter, a target catheter, etc.); and a prosthesis (e.g., a covered nitinol stent graft in a delivery / system (e.g., a 7 Fr (approx. 2.3 mm) delivery / system)). The system or kit optionally further comprises an ultrasound system, a control system (e.g., computer). Some users may already have an appropriate ultrasound system that can be connected to the ultrasound catheter(s). The catheters and prostheses described above may be used in the system or kit, and details of other, additional, and / or modified possible components are described below.

[0443] Figure 14A is a schematic side cross-sectional view of an example embodiment of an ultrasound launching catheter 170 comprising a needle 172 (e.g., a first ultrasound catheter, an arterial catheter (e.g., if extending a needle from artery into vein), a venous catheter (e.g., if extending a needle from vein into artery)). The catheter 170 is placed into an artery with the needle 172 in a retracted state inside a lumen of the catheter 170. The 2026223262   27 Aug 2026 catheter 170 can be tracked over a guidewire (e.g., a 0.014 inch (approx. 0.36 mm) guidewire) and / or placed through a sheath in the artery (e.g., a femoral artery), and advanced up to the point of the total occlusion of the artery (in the tibial artery). The catheter 170 includes a handle 174 that includes a pusher ring 176. Longitudinal or distal advancement of the pusher ring 176 can advance the needle 172 from out of a lumen of the catheter 170, out of the artery and into a vein, as described herein. Other advancement mechanisms for the needle 172 are also possible (e.g., rotational, motorized, etc.). Before, after, and / or during after advancing the needle 172, a guidewire (e.g., a 0.014 inch (approx. 0.36 mm) guidewire) can be placed through the needle 172 (e.g., as described with respect to the guidewire 14 of Figure 3), and this guideware can be referred to as a crossing ware.

[0444] Figure 14B is an expanded schematic side cross-sectional view' of a distal portion of the ultrasound launching catheter 170 of Figure 14A within the circle 14B. Upon advancing or launching, the needle 172 extends radially outwardly from a lumen 173 of the catheter 170. In some embodiments, the lumen 173 ends proximal to the ultrasound transmitting device 178. The needle 172 may extend along a path that is aligned with (e.g., parallel to) the path of the directional ultrasound signal emitted by the ultrasound transmitting device 178. Figure 14B also shows the lumen 175, which can be used to house a guidewsre for tracking the catheter 170 to the desired position.

[0445] Figure 15A is a schematic side elevational view of an example embodiment of an ultrasound target catheter 180 (e.g., a second ultrasound catheter, an arterial catheter (e.g., if extending a needle from vein into artery), a venous catheter (e.g,, if extending a needle from artery into vein)). Figure 15B is an expanded schematic side crosssectional view of the ultrasound target catheter 180 of Figure 15A within the circle 15B. Figure 15C is an expanded schematic side cross-sectional view of the ultrasound target catheter 180 of Figure 15A within the circle 15C. The catheter 180 can be tracked over a guidewire (e.g., a 0.014 inch (approx. 0.36 mm) guidewire) and / or placed through a sheath in the vein (e.g., a femoral vein), and advanced up to a point (e.g,, in the tibial vein) proximate and / or parallel to the distal end of the catheter 170 and / or the occlusion in the artery. The catheter 180 includes an ultrasound receiving transducer 182 (e.g., an omnidirectional ultrasound receiving transducer) that can act as a target in the vein for aligning the needle 172 of the catheter 170. The catheter 180 may be left in place or remain stationary or 2026223262   27 Aug 2026 substantially stationary while the catheter 170 is rotated and moved longitudinally to obtain a good or optimal ultrasound signal indicating that the needle 172 is aligned with and in the direction of the catheter 180.

[0446] The catheters 170, 180 may be connected to an ultrasound transceiver that is connected to and controlled by a computer running transceiver software. As described in further detail herein, the catheter 170 includes a flat or directional ultrasound transmitter 178 configured to transmit an ultrasound signal having a low angular spread or tight beam (e.g., small beam width) in the direction of the path of the needle 172 upon advancement from the lumen 173 of the catheter 170. The catheter 180 includes an omnidirectional (360 degrees) ultrasound receiver 182 configured to act as a target for the ultrasound signal emitted by the directional transmitter 178 of the catheter 170. The catheter 170 is rotated until the peak ultrasound signal is displayed, indicating that the needle 172 is aligned to the catheter 180 such that, upon extension of the needle 172 (e.g., by longitudinally advancing the ring 176 of the handle 174), the needle 172 can pass out of the artery in which the catheter 170 resides, through interstitial tissue, and into the vein in which the catheter 180 resides.

[0447] Figure 16 is an example embodiment of a graph for detecting catheter alignment, as may be displayed on display device of an ultrasound system (e.g., the screen of a laptop, tablet computer, smartphone, combinations thereof, and the like). The graph in Figure 16 shows that the signal originating from the transmitting catheter in the artery? has been received by the receiving catheter in the vein. The second frequency envelope from the right is the received signal. The distance from the left side of the illustrated screen to the leading edge of the second frequency envelope may indicate the distance between the catheters. The operator can move the catheter in the artery both rotationally and longitudinally, for example until the second envelope is maximal, which indicates the catheters are correctly orientated.

[0448] Figure 17 is a schematic side elevational view of an example embodiment of a prosthesis (e.g., stent, stent-graft) delivery system 190. In some embodiments, the delivery system 190 is a 7 Fr (approx. 2.3 mm) delivery system. Figure 18 is a schematic side elevational view of an example embodiment of a prosthesis (e.g., stent, stent-graft) 200. In Figure 17, a prosthesis (e.g., the prosthesis 200, other prostheses described herein, etc.) is in a compressed or crimped state proximate to the distal end 192 of the delivery sy stem 190. In 2026223262   27 Aug 2026 some embodiments, the prosthesis 200 comprises a shape-memory stent covered with a graft material, for example as described above. Once the crossing wire extends from the artery to the vein, for example as a result of being advanced through the needle 172 as described herein, the delivery system 190 can be advanced over the crossing wire. The prosthesis 200 may be deployed from the delivery system 190, for example by squeezing the trigger handle 194 of the delivery system 190, causing the outer cover sheath to proximally retract and / or distally advance the prosthesis 200. The prosthesis 200 can create a flow path between the artery and the vein and through the interstitial tissue. Other types of delivery systems and prostheses are also possible.

[0449] Referring again to Figure 17, some non-limiting example dimensions of the deliver system 190 are provided. The distance 196 of travel of the trigger handle 194 may be, for example, between about 0.4 inches (approx. 1 cm) and about 12 inches (approx. 30 cm), between about 1 inch (approx. 2.5 cm) and about 8 inches (approx. 20 mm), or between about 2 inches (approx. 5 cm) and about 6 inches (approx. 15 mm) (e.g., about 2 inches (approx. 5 cm)). In some embodiments, the distance 196 of travel of the trigger handle 194 is at least as long as the length of the prosthesis 200 to be deployed (e.g., in the radially expanded state). In some embodiments, gearing or other mechanisms may be employed to reduce the distance 196 of travel of the trigger handle 194 be less than the length of the prosthesis 200 to be deployed (e.g., in the radially expanded state). The distance 196 may be adjusted for example, based on at least one of: the length of the prosthesis 200 to be deployed, the degree of foreshortening of the prosthesis 200 to be deployed, the mechanism of deployment (e.g., whether the outer sheath is proximally retracted, the prosthesis 200 is pushed distally forward, or both, whether the deliver}? system 190 includes gearing mechanism, etc.), combinations thereof, and the like. The length 197 of the outer sheath or catheter portion may be, for example, between about 40 inches (approx. 1,020 mm) and about 50 inches (approx. 1,270 ram), between about 46 inches (approx. 1,170 mm) and about 47 inches (approx. 1,190 mm), or between about 46.48 inches (approx. 1,180 mm) and about 46.7 inches (approx. 1,186 mm). The total length 198 of the delivery system 190 from proximal tip to distal tip may be, for example, between about 40 inches (approx. 1,000 mm) and about 60 inches (approx. 1,500 mm). The lengths 197, 198 may be adjusted, for example based on at least one of: length of the prosthesis 200 to be deployed, the degree of 2026223262   27 Aug 2026 foreshortening of the prosthesis 200 to be deployed, the height of the patient, the location of the occlusion being treated, combinations thereof, and the like. In some embodiments, spacing the trigger handle 194 from the vascular access point, for example by between about 10 cm and about 30 cm (e.g., at least about 20 cm) may advantageously provide easier handling or management by the user. In certain such embodiments, the length 197 may be between about 120 cm and about 130 cm (e.g., for an antegrade approach) or between about 150 cm and about 180 cm (e.g., for a contralateral approach).

[0450] Referring again to Figure 18, some non-limiting example dimensions of the prosthesis 200 are provided, depending on context at least in the compressed state. The thickness 201 of a structural strut may be, for example, between about 0.05 mm and about 0.5 mm or between about 0.1 mm and about 0.2 mm (e.g., about 0.143 mm). The spacing 202 between struts of a structural strut may be, for example, between about 0.005 mm and about 0.05 mm or between about 0.01 mm and about 0.03 mm (e.g., about 0.025 mm). The thickness 203 of a linking strut may be, for example, between about 0.05 mm and about 0.5 mm or between about 0.1 mm and about 0.2 mm (e.g., about 0.133 mm). The longitudinal length 204 of the structural components may be, for example, between about 1 mm and about 5 mm or between about 2.5 mm and about 3 mm (e.g., about 2.8 mm). The longitudinal length 205 between structural components may be, for example, between about 0.25 mm and about 1 mm or between about 0.5 mm and about 0.6 mm (e.g., about 0.565 mm). The length 206 of a strut within a structural component, including all portions winding back and forth, may be, for example, between about 25 mm and about 100 mm or between about 65 mm and about 70 mm (e.g., about 67.62 mm). The total longitudinal length of the prosthesis 200 maybe, for example, between about 25 mm and about 150 mm or between about 50 mm and about 70 ram (e.g., about 62 mm). As described herein, a wide variety of laser-cut stents, woven stents, and combinations thereof, including various dimensions, are possible. The struts described herein may comprise wires or filaments or potions not cut from a hypotube or sheet.

[0451] The proximal and / or distal ends of the prosthesis 200 may optionally comprise rings 210. The rings 210 may, for example, help to anchor the prosthesis 200 in the artery and / or the vein. The circumferential width 211 of a ring 210 may be, for example, between about 0.25 mm and about 1 mm or between about 0.5 mm and about 0.75 mm (e.g., 2026223262   27 Aug 2026 about 0.63 mm). The longitudinal length 212 of a ring 210 may be, for example, between about 0.25 mm and about 2 mm or between about 0.5 mm and about 1 mm (e.g., about 0.785 mm). In some embodiments, a ratio of the total length of the prosthesis 200 to the longitudinal length 212 of a ring 210 may be between about 50:1 and about 100:1 (e.g., about 79:1). The dimensions 211, 212 of the rings 210 may be adjusted, for example based on at least one of: strut thickness, diameter of the prosthesis (e.g., relative to the vessel), total length of the prosthesis, material, shape setting properties, combinations thereof, and the like.

[0452] Figure 19 is a schematic side elevational view of another example embodiment of a prosthesis 220. The prosthesis 200 may have the shape of the prosthesis 220, for example in a radially expanded state (e.g., upon being deployed from the deliver}' system 190). Figure 19 illustrates an example shape of the prosthesis 220 comprising a first portion 221 and a second portion 225. The first portion 221 has a substantially cylindrical or cylindrical shape having a length 222 between about 15 mm and about 25 mm (e.g., about 21 mm) and a diameter 223 between about 2.5 mm and about 5 mm (e.g., about 3.5 mm). The second portion 225 has a substantially frustoconical or frustoconical shape having a length 226 between about 30 mm and about 50 mm (e.g., about 41 mm) and a widest diameter 227 between about 4 mm and about 10 mm, between about 4 mm and about 7 mm (e.g., about 5.5 mm), etc. The angle of taper of the second portion 225 away from the first portion 221 may be between about 0.02 degrees and about 0.03 degrees (e.g., about 0.024 degrees).

[0453] Further details regarding prostheses that can be used in accordance with the methods and systems described herein are described in U.S. Patent App. No. 13 / 791,185, filed March 8, 2013, which is hereby incorporated by reference in its entirety.

[0454] Figures 20A-20H schematically illustrate an example embodiment of a method for effecting retroperfusion. The procedure will be described with respect to a peripheral vascular system such as the lower leg, but can also be adapted as appropriate for other body lumens (e.g., cardiac, other peripheral, etc.). Certain steps such as anesthesia, incision specifics, suturing, and the like may be omitted for clarity. In some embodiments, the procedure can be performed from vein to artery (e.g., with the venous catheter coming from below).

[0455] Access to a femoral artery and a femoral vein is obtained. An introducer sheath (e.g., 7 Fr (approx. 2.3 mm)) is inserted into the femoral artery and an introducer 2026223262   27 Aug 2026 sheath (e.g., 6 Fr (approx. 2 mm)) is inserted into the femoral vein, for example using the Seidinger technique. A guidewire (e.g., 0.014 meh (approx. 0.36 mm), 0.035 meh (approx. 0.89 mm), 0.038 meh (approx. 0.97 mm)) is inserted through the introducer sheath in the femoral artery and guided into the distal portion of the posterior or anterior tibial diseased artery 300. A second guidewire (e.g., 0.014 meh (approx. 0.36 mm), 0.035 meh (approx. 0.89 mm), 0.038 meh (approx. 0.97 mm)) or a snare is inserted through the introducer sheath in the femoral vein. In embodiments in which a snare is used, the described third guidewire, fourth guideware, etc. described herein are accurate even though the numbering may not be sequential.

[0456] A venous access needle is percutaneously inserted into a target vein, for example a tibial vein (e.g., the proximal tibial vein (PTV)). In some embodiments, the venous access needle may be guided under ultrasound. In some embodiments, contrast may be injected into the saphenous vein towards the foot (retrograde), and then the contrast will flow into the PTV. This flow path can be captured using fluoroscopy such that the venous access needle can be guided by fluoroscopy rather than or in addition to ultrasound.

[0457] The target vein may be accessed proximate to and distal to (e.g., a few inches or centimeters) below where the launching catheter 310 will likely reside. In some embodiments, the target vein may be in the ankle. Once the venous access needle is in the vein, a third guidewire (or “second” guidewire in the case that a snare is used instead of a second guidewire) is inserted into the venous access needle and advanced antegrade in the target vein up to the femoral vein. This access method can advantageously reduce issues due to advancing wires retrograde across venous valves, which are described in further detail below. The third guidewire is snared, for example using fluoroscopic guidance, and pulled through the femoral vein sheath. The target catheter 320 is inserted into the femoral vein sheath over the third guidewire, which has been snared. The target catheter 320 is advanced over the third guidewire into the venous system until the target catheter is proximate to and / or parallel with the guidewure in the distal portion of the posterior or anterior tibial diseased artery and / or proximate to the occlusion 304, as shown in Figure 20A.

[0458] In some embodiments, the third guidewire may include an ultrasound receiving transducer (e.g., omnidirectional) mounted to provide the target for the signal emitted by the launching catheter 310 or the target catheter 320 could be tracked over the 2026223262   27 Aug 2026 third guidewire, either of which may allow omission of certain techniques (e.g., femoral vein access, introducing vein introducer sheath, inserting second guidewire, antegrade advancing of the third guidewire up to the femoral vein, snaring the third guidewire, advancing the target catheter 320 over the third guidewire).

[0459] In some embodiments, the PTV may be accessed directly, for example using ultrasound, which can allow placement of the target catheter 320 directly into the PTV, for example using a small sheath, which may allow omission of certain techniques (e.g., femoral vein access, introducing vein introducer sheath, inserting second guidewire, antegrade advancing of the third guidewire up to the femoral vein).

[0460] In some embodiments, the catheter 320 is not an over-the-wire catheter, but comprises a guidewire and an ultrasound receiving transducer (e.g., omnidirectional). The catheter 320 may be inserted as the third guidewire, as discussed above, as the second guidewire, or as a guidewire through a small sheath when directly accessing the PTV.

[0461] Ultrasound transducers generally include two electrodes including surfaces spaced by a ceramic that can vibrate. An incoming or received ultrasound signal wave can couple into a length extensional mode, as shown in Figure 21. Figure 21 is a schematic perspective view of an example embodiment of an ultrasound receiving transducer 350. If the proximal or top end 352 of the transducer 350 and the distal or bottom end 354 of the transducer are conductive and electrically connected to wires, the transducer can receive ultrasound signals. In some embodiments, the transducer 350 has a length 356 between about 0.1 mm and about 0.4 mm (e.g., about 0.25 ram). In some embodiments, the transducer 350 has an overlap length 358 between about 0.1 mm and about 0.3 mm (e.g., about 0.2 mm). In some embodiments, the transducer 350 has a diameter that is similar to, substantially similar to, or the same as the guidewire on which it is mounted. In some embodiments, an array or series of laminates may enhance the signal-receiving ability of the transducer 350.

[0462] In some embodiments, a guidewire comprising an ultrasound receiving transducer may comprise a piezoelectric film (e.g., comprising plastic), which could enhance the signal-receiving ability of the transducer. Figure 22 is a schematic cross-sectional view of another example embodiment of an ultrasound receiving transducer 360. The ultrasound receiving transducer 360 shown in Figure 22 includes an optional lumen 368. The ultrasound receiving transducer 360 includes a series of layers 362, 364, 366. The layer 362 may 2026223262   27 Aug 2026 comprise a polymer (e.g., polyvinylidene fluoride (PVDF)) layer. The layer 364 may comprise an inorganic compound (e.g., tungsten carbide) layer. The layer 366 may comprise a polymer (e.g., polyimide) layer. The layer 366 may have a thickness between about 25 micrometers (gm or microns) and about 250 gm (e.g., at least about 50 gm).

[0463] The launching catheter 310 is tracked over the guidewire in the femoral and tibial arteries proximate to and proximal to the occlusion 304, as shown in Figure 20B. The catheter 310 may be more proximal to the occlusion 304 depending on suitability at that portion of the anatomy for the retroperfusion process. In some embodiments, the catheter 310 may be positioned in the distal portion of the posterior or anterior tibial artery', for example proximate to the catheter 320. In some embodiments, the catheter 310 may be positioned within a few inches or centimeters of the ankle.

[0464] The launching catheter 310 emits a directional ultrasound signal. As shown by the arrow 311, 312 in Figure 20C, the launching catheter 310 is rotated and moved longitudinally until the signal is received by the target catheter 320. Once the signal is received, which indicates alignment such that extension of the needle form the launching catheter 310 will result in successful access of the vein, a crossing needle 314 is advance out of the catheter 310, out of the tibial artery' 300 and into the tibial vein 302, as shown in Figure 20D. Accuracy of the placement of the crossing needle 314 to form a fistula between the artery 300 and the vein 302 may be confirmed, for example, using contrast and fluoroscopy.

[0465] In some embodiments, the ultrasound signal can be used to determine the distance between the artery 300 and the vein 302. Referring again to Figure 16, the distance from the left side of the illustrated screen to the leading edge of the second frequency envelope can be used as an indicator of distance between the catheters.

[0466] Referring again to Figure 16, a display device may graphically show signal alignment peaks to allow the user to determine the alignment position. In some embodiments, the signal alignment may change color above or below7 a threshold value, for example from red to green. In some embodiments, an audio signal may be emitted, for example when an alignment signal crosses over a threshold value, which can allow7 a user to maintain focus on the patient rather than substantially continuously monitoring a screen. 2026223262   27 Aug 2026

[0467] In some embodiments, a horizontal line on the screen may move up to indicate the maximum signal value or peak achieved to that point during the procedure. This line may be called “peak hold.” If a greater signal value is achieved, the horizontal line moves to match that higher value. If no manipulation is able to raise the peak above the horizontal line, that can indicate maximum alignment. If the signal peak falls a certain amount below the horizontal line, the catheters may have moved and no longer be properly aligned. Since the level of alignment indicated by the horizontal line has previously been achieved during the procedure, the user knows that such a level of alignment can be achieved by further rotational and / or longitudinal manipulation.

[0468] A fourth guidewire 316 (e.g., 0.014 inch (approx. 0.36 mm)) (or “third” guidewire in the case that a snare is used instead of a second guidewire) is placed through the lumen of the crossing needle 314 of the catheter 310 and into the tibial vein 302 in a retrograde direction (of the vein 302) towards the foot, as shown in Figure 20E. External cuff pressure may be applied above the needle crossing point to reduce flow in the artery 300 to inhibit or prevent formation of a hematoma, and / or to engorge the vein to facilitate valve crossing. The catheters 310, 320 may be removed, leaving the guidewire 316 in place, extending from the introducer sheath in the femoral artery, through the arterial tree, and into the tibial vein 302.

[0469] Certain techniques for crossing a guidewire 316 from an artery 300 to a vein 302 may be used instead of or in addition to the directional ultrasound techniques described herein.

[0470] In some embodiments, a tourniquet can be applied to the leg, which can increase vein diameters. In some embodiments, a blocking agent (e.g., as discussed with respect to Figures 4 and 7, a blocking balloon, etc.) may be used to increase vein diameter. For example, venous flow could back up, causing dilation of the vein. A larger vein diameter can produce a larger target for the crossing needle 314, making the vein 300 easier to access with the crossing needle 314.

[0471] In some embodiments, a PT A balloon can be used in the target vein, and a needle catheter (e.g., Outback, available from Cordis) can target the PTA balloon under fluoroscopy. The crossing needle 314 can puncture the PTA balloon, and the reduction in pressure of the PTA balloon can confirm proper alignment of the crossing needle 314. The 2026223262   27 Aug 2026 PTA balloon can increase vein diameter, producing a larger target for the crossing needle 314, making the vein 300 easier to access with the crossing needle 314. The guidewire 316 may be advanced through the crossing needle 314 and into the PTA balloon.

[0472] In some embodiments, the PTA balloon comprises a mesh (e.g., a woven mesh), for example embedded in the polymer of the balloon. When a balloon without such a mesh is punctured, the balloon material could rupture and cause emboli (e.g., pieces of the balloon floating downstream). The mesh can help to limit tearing of the balloon material, which can inhibit or prevent balloon material from causing emboli. In some implementations, a balloon without a mesh can be configured to snare a guideware upon being collapsed (e.g., by entangling the guidewire in folds of the balloon), whether or not punctured.

[0473] In some embodiments, two PTA balloons spaced longitudinally along the axis of the catheter can be used in the target vein, and a needle catheter can target the one of the PTA balloons. Upon puncturing of one of the PTA balloons by the crossing needle 314, contrast in a well between the PTA balloons can be released because the punctured balloon no longer acts as a dam for the contrast. The release of contrast can be monitored using fluoroscopy. The PTA balloons can be on the same catheter or on different catheters.

[0474] In some embodiments, two PTA balloons spaced longitudinally along the axis of the catheter can be used in the target vein, and a needle catheter can target the space or well between the PTA balloons. Upon puncturing of the well by the crossing needle 314, contrast in the well can be disturbed. The disturbance of contrast can be monitored using fluoroscopy. The PTA balloons can be on the same catheter or on different catheters.

[0475] In some embodiments in which a PTA balloon may be used in combination with an ultrasound target in the target vein, a PTA balloon catheter includes a PTA balloon and an ultrasound receiving transducer (e.g., omnidirectional). In certain such embodiments, the launching catheter 310 can target the PTA balloon under fluoroscopy and / or can target the ultrasound receiving transducer as described herein. The crossing needle 314 can puncture the PTA balloon, and the reduction in pressure of the PTA balloon can confirm proper alignment of the crossing needle 314. The PTA balloon can increase vein diameter, producing a larger target for the crossing needle 314, making the vein 300 easier to access with the crossing needle 314. The guidewire 316 may be advanced through the crossing needle 314 and into the PTA balloon. 2026223262   27 Aug 2026

[0476] In some embodiments, a LeMaitre device (e.g., the UnBalloon™ NonOcclusive Modeling Catheter, available from LeMaitre Vascular of Burlington, Massachusetts) can be used in the target vein. In some embodiments, a LeMaitre device can increase vein diameters. A larger vein diameter can produce a larger target for the crossing needle 314, making the vein 300 easier to access with the crossing needle 314. In some embodiments, the needle 314 can penetrate into the LeMaitre device. In certain such embodiments, the LeMaitre device can act as a mesh target (e.g., comprising radiopaque material visible under fluoroscopy) for the crossing needle 314. The mesh of the LeMaitre device can be radially expanded by distally advancing a proximal portion of the mesh and / or proximally retracting a distal portion of the mesh (e.g., pushing the ends together like an umbrella) and / or by allowing the mesh to self-expand (e.g., in embodiments in which at least some parts of the mesh comprise shape-memory material). In some embodiments, a LeMaitre device can grip a crossing wire to hold the crossing wire in the target vein as the LeMaitre device closes.

[0477] In some embodiments, the launching catheter 310 may comprise a first magnet having a first polarity and the target catheter 320 may comprise a second magnet having a second polarity. When the magnets are close enough for magnetic forces to move one or both of the catheters 310, 320, the crossing needle 314 may be advanced to create the fistula between the artery' 300 and the vein 302. In some embodiments, the first magnet maybe circumferentially aligned with the crossing needle 314 and / or the launching catheter 310 may be magnetically shielded to provide rotational alignment. In some embodiments, the second magnet may be longitudinally relatively thin to provide longitudinal alignment. In some embodiments, the crossing needle 314 and / or the guidewire 316 may be magnetically pulled from the artery 300 to the vein 302, or vice versa. Some systems may include both ultrasound guidance and magnetic guidance. For example, ultrasound guidance could be used for initial alignment and magnetic guidance could be used for refined alignment.

[0478] Referring again to Figures 20A-20H, a prosthesis delivery system 330 carrying a prosthesis 340 is tracked over the guidewire 316 through the interstitial space between the artery 300 and the vein 300 and then into the vein 302, as shown in Figure 20F. In some embodiments, a separate PTA balloon catheter (e.g., about 2 mm) can be tracked over the guidewire 316 to pre-dilate the fistula between the artery 300 and the vein 302 prior 2026223262   27 Aug 2026 to introduction of the prosthesis delivery system 330. Use of a PTA balloon catheter may depend, for example, on the radial strength of the prosthesis 340.

[0479] The prosthesis 340 is deployed from the prosthesis delivery system 330, for example by operating a trigger handle 194 (Figure 17). In some embodiments, for example if the prosthesis 340 is not able to expand and / or advance, the prosthesis delivery system 330 may be removed and a PTA catheter (e.g., about 2 mm) advanced over the guidewire 316 to attempt to dilate or further dilate the fistula the artery 300 and the vein 302. Deployment of the prosthesis 340 may then be reattempted (e.g., by self-expansion, balloon expansion, etc.). In some embodiments, deployment of the prosthesis 340 may remodel a vessel, for example expanding the diameter of the vessel by at least about 10%, by at least about 20%, by at least about 30%, or more, by between about 0% and about 10%, by between about 0% and about 20%, by between about 0% and about 30%, or more. In embodiments in which the prosthesis 340 is self-expanding, the degree of remodeling may change over time, for example the prosthesis 340 expanding as the vessel expands or contracting when the vessel contracts.

[0480] Once the prosthesis 340 is deployed, as shown in Figure 20G, the fistula may be dilated with a PTA catheter. The diameter of the PTA catheter (e.g., about 3 mm to about 6 mm) may be selected based at least in part on: the diameter of the artery' 300, the diameter of the vein 302, the composition of the interstitial tissue, the characteristics of the prosthesis 340, combinations thereof, and the like. In some embodiments, the prosthesis delivery system 330 may comprise a PTA balloon catheter (e.g., proximal or distal to the prosthesis 340) usable for one, several, or all of the optional PTA balloon catheter techniques described herein. In embodiments in which the prosthesis comprises a conical portion, the PTA balloon may comprise a conical portion. Once the prosthesis 340 is in place, the prosthesis delivery system 330 may be removed, as shown in Figure 20H. An AV fistula is thereby formed between the artery 300 and the vein 302. Confirmation of placement of various catheters 310, 320, 330 and the prosthesis 340 may be confirmed throughout parts or the entire procedure under fluoroscopy using contrast injections.

[0481] In some embodiments, a marker (e.g., a clip a lancet, scissors, a pencil, etc.) may be applied (e.g., adhered, placed on top of, etc.) to the skin to approximately mark the location of the fistula formed between the artery 300 and the vein 302 by the crossing 2026223262   27 Aug 2026 needle 314 prior to deployment of the prosthesis 340. In embodiments in which the user uses a sphygmomanometer inflated above the fistula to avoid bleeding, the lack of blood flow can render visualization or even estimation of the fistula site difficult, and the marker can provide such identification. In embodiments in which the transmitting and receiving catheters are removed after fistula formation, the cross-over point may be difficult for the user to feel or determine, and the marker can provide such identification. If the fistula is to be dilated, a midpoint of the dilation balloon may be preferably aligned with the midpoint of the fistula (e.g., to increase or maximize the hole-through interstitial space). In some embodiments, the marker may be visualized under fluoroscopy (e.g., comprising radiopaque material) to allow the user to see and remember the location of the fistula under fluoroscopy prior to deployment of the prosthesis 340.

[0482] Once the prosthesis 340 is in place, an obstacle to blood flowing through the vein 302 and into the foot are the valves in the veins. Steering a guidewire across venous valves can be a challenge, for example because pressure from the artery' may be insufficient to extend the veins and make the valves incompetent. The Applicant has discovered that venous valves distal to the AV fistula can be disabled or made incompetent using one or more of a variety of techniques such as PTA catheters, stents (e.g., covered stents, stentgrafts, etc.), and a valvulotome, as described in further detail below. Disabling venous valves can allow blood to flow via retroperfusion from the femoral artery, retrograde in the vein 302, and retrograde in the vein to the venuoles and capillaries to the distal part of the venous circulation of the foot to provide oxygenated blood to the foot in CLI patients.

[0483] In some embodiments, a high-pressure PTA balloon catheter may be used to make venous valves incompetent (e.g., when inflated to greater than about 10 atm (approx. 1,013 kilopascals (kPa))).

[0484] In some embodiments, one or more stents can be placed across one or more venous valves to render those valves incompetent. For example, such stents should have sufficient radial force that the valves stay open. The stent may forcefully rupture the valves. In some embodiments, the stent comprises a covering or a graft. Certain such embodiments can cover venous collateral vessels. In some embodiments, the stent is bare or free of a covering or graft. Certain such embodiments can reduce costs. The venous stent may extend along a length (e.g., an entire length) of the vein. For example, in some 2026223262   27 Aug 2026 embodiments, the entire length of the PTV is lined with a covered stent, covering the venous collaterals, disrupting venous valves.

[0485] In some embodiments, the venous stent is separate from the fistula prosthetic. A separate venous stent may allow more flexibility in properties such as dimensions (e.g., length, diameter), materials (e.g., with or without a covering or graft), and other properties. Figure 31A schematically illustrates an example embodiment of an arteriovenous fistula stent 340 separate from an example embodiment of a venous stent 342. The venous stent 342 may be spaced from the fistula stent 340 (e.g., as illustrated in Figure 31 A), abutting the fistula stent 340, or overlapping, telescoping, or coaxial with the fistula stent 340 (e.g., a distal segment of the fistula stent 340 being at least partially inside a proximal segment of the venous stent 342 or a proximal segment of the venous stent 342 being at least partially inside a distal segment of the fistula stent 340). In embodiments in which the fistula stent 340 and the venous stent 342 overlap, placement of the venous stent 342 first can allow the proximal end of the venous stent 342, which faces the direction of retrograde blood flow, to be covered by the fistula stent 340 to reduce or eliminate blood flow disruption that may occur due the distal end of the venous stent 342. In embodiments in which the fistula stent 340 and the venous stent 342 overlap, placement of the venous stent 342 second can be through the fistula stent 340 such that both stents 340, 342 can share at least one deployment parameter (e.g., tracking stent deployment devices over the same guidewire). The venous stent 342 may be deployed before or after the fistula stent 340. The venous stent 342 may have a length between about 2 cm and about 30 cm (e.g., about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, about 30 cm, ranges between such values, etc.).

[0486] In some embodiments, the venous stent is integral with the fistula prosthetic. An integral venous stent may allow'’ more flexibility in properties such as dimensions (e.g., length, diameter), materials (e.g., with or without a covering or graft), and other properties. Figure 3 IB schematically illustrates an example embodiment arteriovenous fistula stent 344 comprising an integrated venous stent. Figure 3IC schematically illustrates 2026223262   27 Aug 2026 an example embodiment of fistula stent 344 comprising an integrated venous stent. The stent 344 comprises a first portion 346 configured to anchor in an artery, a second portion 350 configured to anchor in and line a length of a vein, and a third portion 348 longitudinally between the first portion 346 and the second portion 350. In embodiments in which the first portion 346 and the second portion 350 have different diameters (e.g., as illustrated in Figure 3 IC), the third portion 348 may be tapered. In some embodiments, a portion of the second portion 350 that is configured to line a vein has a different property (e.g., diameter, material, radial strength, combinations thereof, and the like) than other portions of the second portion 350. A length of the second section 350 may be greater than a length of the first section 346. For example, the second section 350 may have a length configured to line a vessel such as the PTV. The second section 350 may have a length between about between about 2 cm and about 30 cm (e.g., about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, about 30 cm, ranges between such values, etc.).

[0487] In some in situ bypass procedures, a saphenous vein is attached to an artery in the upper leg and another artery in the lower leg, bypassing all blockages in the artery. In certain such procedures, the vein is not stripped out of the patient, flipped lengthwise, and used as a prosthesis, but rather is left in place so that blood flow is retrograde (against the valves of the vein). A standard valvulotome may be placed into the saphenous vein from below and advanced to the top in a collapsed state, opened, and then pulled backwards in an open state, cutting venous valves along the way. Cutting surfaces of such valvulotomes face backwards so as to cut during retraction during these procedures. Figure 23A is a schematic perspective view of an example embodiment of a valvulotome 400 that may be used with such procedures, including blades 402 facing proximally.

[0488] In some embodiments of the methods described herein, access distal to the vein valves is not available such that pulling a valvulotome backwards is not possible, but pushing a reverse valvulotome as described herein forward is possible. Figure 23B is a schematic perspective view' of an example embodiment of a valvulotome 410 that may be used with such procedures. The reverse valvulotome 410 includes one or a plurality of blades 2026223262   27 Aug 2026 412 (e.g., two to five blades (e.g., three blades)) facing forward or distal such that valves can be cut as the reverse valvulotome 410 is advanced distally. At least because retrograde access to veins to be disabled has not previously been recognized as an issue, there has been no prior motivation to reverse the direction of the blades of a valvulotome to create a reverse valvulotome 410 such as described herein. The reverse valvulotome 410 may be tracked over a guidewire 414, which can be steered into the veins, for making the venous valves incompetent. After forming a fistula between an artery and a vein as described herein, the flow of fluid in the vein is in the direction opposite the native or normal or pre-procedure direction of fluid flow in the vein such that pushing the reverse valvulotome 410 is in a direction opposite native fluid flow but in the direction of post-fistula fluid flow.

[0489] Other systems and methods are also possible for making the valves in the vein incompetent (e.g., cutting balloons, atherectomy, laser ablation, ultrasonic ablation, heating, radio frequency (RF) ablation, a catheter with a tip that is traumatic or not atraumatic (e.g., an introducer sheath) being advanced and / or retracted, combinations thereof, and the like).

[0490] Crossing vein valves in a retrograde manner before such valves are made incompetent can also be challenging. Figure 24 is a schematic perspective view of an example embodiment of a LeMaitre device 420 that may be used to radially expand the veins, and thus their valves. The LeMaitre device 420 includes an expandable oval or oblong leaf shape 422, for example a self-expanding nitinol mesh. In some embodiments, a PTA balloon catheter may be used to radially expand the veins, and thus their valves. In some embodiments, application of a tourniquet to the leg can radially expand the veins, and thus their valves. Upon radial expansion, a guidewire can be advanced through the stretched valve(s) (e.g,, through an expansion device such as the LeMaitre device) and catheters (e.g., PTA, stent deliver} / , atherectomy (e.g., directional, orbital, laser, etc.), etc.) or other over-the-wire devices can be advanced over the guidewire.

[0491] Figures 26A and 26B schematically illustrate another example embodiment of a method for effecting retroperfusion. Referring again to Figure 20E, a fistula may be created between an artery 600 including an occlusion 604 and a vein 602 with a guidewire 606 extending therethrough using one or more of the techniques described herein and / or other techniques. A prosthesis delivery system carrying a prosthesis 620 is tracked 2026223262   27 Aug 2026 over the guidewire 606 through the interstitial space between the artery 600 and the vein 602 and then into the vein 602, as shown in Figure 26A. In some embodiments, a separate PTA balloon catheter (e.g., about 2 mm) can be tracked over the guidewire 606 to pre-dilate the fistula between the artery 600 and the vein 602 prior to introduction of the prosthesis delivery system. Use of a PTA balloon catheter may depend, for example, on the radial strength of the prosthesis 620. The prosthesis 620 may be the stent 500, 520, 540 of Figures 25A-25C or variations thereof (e.g., as described with respect to Figure 25C), which include uncovered and low porosity woven filaments configured to divert blood flow.

[0492] The flow diverting properties of uncovered woven filaments may depend on certain hemodynamic characteristics of the vascular cavities. For example, if the occlusion 604 is not total such that some pressure drop may occur between the lumen of the prosthesis 620 and the portion of the artery 600 between the occlusion 604 and the prosthesis 620, blood may be able to flow through the sidewalls of the prosthesis 620 rather than into the fistula. Referring again to Figure 4 and the description of the blocking material 251, blocking material 608 may optionally be provided in the artery' 600 to further occlude the artery 600, which can inhibit hemodynamic effects that might cause and / or allow blood to flow through the sidewalls of the prosthesis 620. For another example, a pressure drop between the artery 600 and the vein 602 might cause and / or allow' blood to flow through the sidewalls of the prosthesis in the normal direction of venous blood flow' rather than through the lumen of the prosthesis to effect retroperfusion. Referring again to Figure 4 and the description of the blocking material 251, blocking material 610 may optionally be provided in the vein 602 to occlude the portion of the vein 602 downstream to the fistula under normal venous flow, which can inhibit hemodynamic effects that might cause and / or allow blood to flow through the sidewalls of the prosthesis 620.

[0493] The prosthesis 620 is deployed from the prosthesis delivery / system, for example by operating a trigger handle 194 (Figure 17). In some embodiments, for example if the prosthesis 620 is not able to expand and / or advance, the prosthesis delivery system may be removed and a PTA catheter (e.g., about 2 mm) advanced over the guidewire 620 to attempt to dilate or further dilate the fistula the artery 600 and the vein 602. Deployment of the prosthesis 620 may then be reattempted (e.g., by self-expansion, balloon expansion, etc.). In some embodiments, deployment of the prosthesis 620 may remodel a vessel, for example 2026223262   27 Aug 2026 expanding the diameter of the vessel as described herein. In embodiments in which the prosthesis 620 is self-expanding, the degree of remodeling may change over tune, for example the prosthesis 620 expanding as the vessel expands or contracting when the vessel contracts. The prosthesis 620 may be conformable to the anatomy in which the prosthesis 620 is deployed. For example, in an expanded state on a table or benchtop, the prosthesis 620 may be substantially cylindrical, but the prosthesis 620 may conform to the diameters of the vessels and fistula in which the prosthesis 620 is deployed such that the prosthesis may have different diameters in different longitudinal segments, tapers, non-cylindrical shapes, combinations thereof, and the like.

[0494] In some embodiments in which the prosthesis 620 comprises a supplemental support structure (e.g., as described with respect to Figure 25B), deployment of the prosthesis may comprise deploying the first woven structure and, before, during, and / or after deploying the first woven structure, deploying the supplemental support structure.

[0495] The fistula may optionally be dilated with a PTA catheter before, during, and / or after deploying the prosthesis 620. The diameter of the PTA catheter (e.g., about 3 mm to about 6 mm) may be selected based at least m part on: the diameter of the artery' 600, the diameter of the vein 602, the composition of the interstitial tissue, the characteristics of the prosthesis 620, combinations thereof, and the like.

[0496] Once the prosthesis 620 is in place, the prosthesis delivery? system may be removed, as shown in Figure 26B. An AV fistula is thereby formed between the artery 600 and the vein 602, Blood flows through the lumen of the prosthesis 620 even though the prosthesis lacks or is free from graft material due to the hemodynamic effects of the low porosity (e.g., less than about 50% porosity or other values described herein). Figure 26B shows an implementation in which the blocking material 608, 610 was not used. Once the prosthesis 620 is in place, valves in the veins may be made incompetent, for example as described herein.

[0497] In embodiments in which the prosthesis 620 comprises two pluralities of filaments that may be deployed separately (e.g., as described with respect to certain embodiments of Figure 25B), the pluralities of filaments may be deployed at least partially? simultaneously, sequentially deployed without intervening steps, or sequentially with intervening steps such as the PTA steps described herein. 2026223262   27 Aug 2026

[0498] Figure 27 schematically illustrates another example embodiment of a prosthesis 720 and a method for effecting retroperfusion. Although some dimensions and even an example scale of “10mm” are provided, the shapes, dimensions, positional relationships, etc. of the features illustrated therein may vary. The prosthesis 720 is positioned in an artery 700 including an occlusion 704, in a vein 702, and spanning interstitial tissue T between the artery 700 and the vein 702. The prosthesis 720 may be positioned, for example, as described herein and / or using other methods. In some embodiments, the prosthesis 720 is delivered through a delivery system having a 5 Fr (1.67 mm) inner diameter over a guidewire having a 2 Fr (0.67 mm) outer diameter.

[0499] In some embodiments, the porosity of the first longitudinal section 722, the second longitudinal section 724, and / or the third longitudinal section 726, or one or more portions thereof may be between about 0% and about 50% and ranges therebetween, for example as described herein. Blood flow from the artery 700 may be diverted into the vein 702 through the prosthesis 720, for example due to hemodynamic forces such as a pressure difference between the artery 700 and the vein 702. The low' porosity of the prosthesis 720 may allow the fluid to flow substantially through the lumen of the prosthesis 720 substantially without perfusing through the sidewalls of the prosthesis 720. In some embodiments, proximal and / or distal portions towards the ends of the prosthesis 720 may be configured to appose vessel sidewalls, for example having a lower porosity, since blood is not likely to flow through those portions.

[0500] The techniques described herein may be useful for forming a fistula between two body cavities near the heart, in the periphery, or even in the lower extremity such as the plantar arch. Figures 28A and 28B schematically illustrate arteries and veins of the foot, respectively. A fistula or anastomosis may be formed between two blood vessels in the foot. In one example, a passage from an artery to a vein was formed in the mid-lateral plantar, from the lateral plantar artery to the lateral plantar vein.

[0501] The artery supplying blood to the foot was occluded and the subintimal space was calcific. A wire was urged distally, and traversed into an adjacent vein. The hole between the artery and the vein was dilated with a 1.5 mm balloon, for example because a small arteriovenous fistula should not cause much if any damage for the patient at that position and in that position. After dilatation, blood started to flow from the artery to the vein 2026223262   27 Aug 2026 without leakage. .After such flow was confirmed, further dilatation of the space was performed using larger balloons (2.0 mm, 2.5 mm, 3.0 mm) at larger pressures (e.g., 20-30 atm). Leakage was surprisingly minimal or non-existent, even without placement of a stent, graft, scaffolding, or other type of device. Procedures not including a prosthesis may reduce costs, procedure time, complexity, combinations thereof, and / or the like. The lateral plantar vein goes directly into the vein arch of the forefoot, making it an excellent candidate for supplying blood to that portion of the foot. The patient had a lot of pain in the foot prior to the procedure and no pain in the foot after the procedure, indicating that blood was able to be supplied through the vein retrograde, as described herein. Fistula or anastomosis maintaining devices may optionally be omitted for certain situations, such as for hemodialysis in which a distal or lower extremity artery and vein may be described as “glued” in surrounding tissue (e.g., mid-lateral plantar artery and vein) /

[0502] In some situations, a fistula or anastomosis maintaining device may be optionally used. Several fistula maintaining devices are described herein. Figure 29 schematically illustrates an example embodiment of an anastomosis device 800. The anastomosis device includes a first section 802, a second section 804, and optionally a third section 806 longitudinally between the first section 802 and the second section 804. The first section 802 may be configured to anchor in a first body cavity (e.g., blood vessel such as an artery or vein). The first section 802 may include expandable members, barbs, etc. The second section 804 may be configured to anchor in a second body cavity (e.g., blood vessel such as an artery or vein, which may be the opposite type of the first body cavity). The third section 806 may be configured to span between the lumens of the first body cavity and the second body cavity. In some embodiments, the space between the lumens of the first body cavity and the second body cavity generally comprises the vessel walls such that the dimensions of the third section 806 may be small or even omitted.

[0503] Some anastomosis devices are available and / or have been developed for the treating holes in larger vessels (e.g., Spyder from Medtronic, CorLink from Johnson and Johnson, Symmetry from St. Jude Medical, PAS-Port from Cardica, and ROX Coupler from ROX Medical). Such devices may be appropriate for use in the periphery or the lower extremity, for example if resized and / or reconfigured. Other devices are also possible. 2026223262   27 Aug 2026 [0504^ Figure 30 schematically illustrates an example embodiment of two blood vessels 902 and 904 coupled together with an anastomosis device 800 spanning the walls of the blood vessels 902, 904. The blood vessel 902 is an artery, as schematically shown by having thick walls, and the blood vessel 904 is a vein. Other combinations of blood vessels and other body cavities are also possible. After a passage 906 is formed between the first blood vessel 902 and the second blood vessel 904, for example as described herein (e.g., using a wire, a deployable needle, one or more balloons, etc.), the anastomosis device 800 is deployed. For example, the distal end of an anastomosis device 800 deployment system may reside in the first blood vessel 902 and extend partially through the passage 906. The first section 802 of the anastomosis device 800 may be deployed through the passage 906 and in the second blood vessel 904. Upon deployment, the first section 802 may self-expand, for example to appose the walls of the second vessel 904. The third section 806 of the anastomosis device 800 may be deployed through the passage 906. Upon deployment, the third section 806 may self-expand, for example to appose the tissue surrounding the passage 906 and to maintain patency through the passage 906. The second section 804 of the anastomosis device 800 may be deployed in the first blood vessel 902. Upon deployment, the second section 804 may self-expand, for example to appose the walls of the first vessel 902. One or more of the first section 802, the second section 804, and the third section 806 may be expanded using a balloon. Different balloons or series of balloons can be used for different of the sections 802, 804, 806 of the anastomosis device 800.

[0505] Figures 32A through 32D illustrate an example method and device for identifying and avoiding a bifurcation 1104 in a percutaneous bypass procedure. A first vessel 1000 (e.g., an artery) is occluded by an occlusion 1008. The occlusion 1008 may be partial or complete (e.g., causing critical limb ischemia). A percutaneous procedure, for example as described herein, can use a second vessel 1002 (e.g., a vein) to bypass the occlusion 1008. A first catheter 1010 resides in the first vessel 1000. A second catheter 1020 resides in the second vessel 1002. The second vessel 1002 includes a bifurcation 1004 at a junction with a branch or collateral vessel 1006. The first catheter 1010 comprises ultrasound transmitter 1012 (e.g., a directional transmitter) configured to send a signal 1014 to an ultrasound receiver 1022 (e.g., an omnidirectional received) of the second catheter 1020 in the second vessel 1002, for example as described herein. A needle 1016 (Figure 32D) may 2026223262   27 Aug 2026 extend out of the first catheter 1010 towards the second vessel 1002. In the configuration shown in Figure 32A, if the needle 1016 extends at the same angle as the signal 1014, for example as described herein (e.g., Figure 3), then the needle 1016 may extend into the bifurcation 1004 and into the branch vessel 1006. Subsequent navigation of a guidewire through a lumen of the needle 1016 may disadvantageously be into the branch vessel 1006 rather than second vessel 1002. Navigation in the branch vessel 1006 rather than the second vessel 1002 may be difficult to detect by the user.

[0506] Figure 32B illustrates a first step in an example method of diagnosing the existence and / or location of the bifurcation 1004. The expandable member 1024 is expanded, for example by providing fluid flow (e.g., saline, contrast materials, etc.) through an inflation lumen 1026 in fluid communication with the expandable member. In Figures 32A-32D, the second catheter 1020 comprises an integral expandable member 1024 (e.g., comprising a balloon) and an inflation lumen 1026. A separate catheter comprising an expandable member may be used in the second vessel 1002. Expansion of the expandable member 1024 occludes the second vessel 1002. As shown by the arrows 1027, blood is still flowing towards the expandable member 1020 from both from a proximal end of the second vessel 1002 and from the branch vessel 1006. The occlusion of the second vessel 1002 and the blood still flowing into the second vessel 1002 can cause the second vessel 1002 to expand. Expansion of the second vessel 1002 can make the second vessel easier to target and / or puncture with the needle 1016.

[0507] Figure 32C shows the introduction of contrast material 1028 in the second vessel 1002, The contrast material 1028 maybe delivered through an infusion port integral with the second catheter 1020 and / or using a separate catheter in the second vessel 1002. The contrast material 1028 may comprise, for example contrast agents or contrast media configured to improve fluoroscopy including iodine-based, barium sulfate-based (e.g,, for subjects with impaired kidney function), combinations thereof, and the like. The contrast material 1028 can contribute to expansion of the second vessel 1002. The contrast material 1028 flow's until reaching the expandable member 1024, then begins to gather proximate to the expandable member 1024. A portion of the contrast material 1028 may gather in the bifurcation 1004, making the existence and location of the bifurcation 1004 and / or the branch vessel 1006 visible under fluoroscopy. Without the expandable member 1024, the contrast 2026223262   27 Aug 2026 material 1028 would flow through the second vessel 1002 without showing the bifurcation 1004 and / or the branch vessel 1006. With knowledge of the angle of the needle 1016, and the position of the first catheter 1010, the user can determine whether the needle 1016 would extend into the bifurcation 1004 and / or the branch vessel 1006. Since this situation would generally result in ineffective bypass, a different puncture site for forming a fistula may be selected.

[0508] In Figure 32D, the first catheter 1010 has been retracted by a distance 1018. The ultrasound signal 1014 (Figure 32A) from the first catheter 1010 may be used to target the second catheter 1020. The procedure shown in Figures 32B and 32C may be repeated, for example looking for another bifurcation. Once the user is satisfied with that the needle 1016 will puncture the second vessel 1002 at a position free from a bifurcation to inhibit or prevent advancement into a branch vessel rather than the second vessel 1002, the needle 1016 may be extended from the first catheter 1010, out of the first vessel 1000, through interstitial tissue between the first vessel 1000 and the second vessel 1002, and into the second vessel 1002 at a position at which the second vessel 1002 does not include a bifurcation or branch vessel. The needle 1016 may be extended with the expandable member 1024 inflated or deflated, or even with the second catheter 1020 removed from the second vessel 1002. In some embodiments, a permanent occluder may be positioned in the second vessel 1002, for example as described herein (e.g., Figure 4). A guidewire may be tracked through a lumen of the needle 1016, and other procedures as described herein, for example fistula dilation, deployment of a fistula prosthesis, deployment of a stent graft, use of a reverse valvulotome, etc., can be performed by tracking a catheter over guidewire (e.g., through the first vessel 1000, through the fistula, and then through the second vessel 1002). In some embodiments, the devices and methods described herein can be used to guide a needle into a bifurcation and / or a branch vessel if desired by the user.

[0509] Figures 33A and 33B schematically illustrate an example procedure that can be performed the following connection of a first vessel 1100 (e.g., an artery) and a second vessel 1102 (e.g., a vein) with a needle 1116 traversing interstitial tissue 1101. The needle 1116 extends from a first catheter 1110 in the first vessel 1100. The first vessel 1100 is occluded by an occlusion 1108. In Figure 33A, a guidewire 1118 extends through a lumen in the needle 1116, and can then be navigated through the second vessel 1102. The needle 2026223262   27 Aug 2026 1116 may be retracted upon placement of the guidewire 1118, and the first catheter 1110 may be retracted from the first vessel 1100. As illustrated in Figure 33B, a second catheter 1120 maybe tracked over the guidewire 1118 through the first vessel 1100, through the interstitial tissue 1101, and into the second vessel 1102. In Figure 33B, the second catheter 1120 comprises a balloon catheter comprising a balloon 1122 (e.g., a PTA balloon). Inflation of the balloon 1122 can dilate a fistula formed between the first vessel 1100 and the second vessel 1102. Dilation of the interstitial tissue 1101 and / or aperture in the vessels 1100, 1102 can enhance later procedures, such as placement of a prosthesis across the fistula.

[0510] Figures 34A through 35F illustrate example procedures that can be performed when a guidewire 1118 is in a vessel 1102 (e.g., a vein). In Figure 34A, a prosthesis 1124 has been placed across the interstitial tissue 1101 between the first vessel 1100 in the second vessel 1102. The deployment system for placing the prosthesis 1124 may have been tracked over the guidewire 1118. A catheter 1130A is tracked over the guidewire 1118 distal to the prosthesis 1124. As shown in Figure 34B, the catheter 1130A may be tracked all the way towards a heel 1103 of the subject.

[0511] As shown in Figure 34C, the catheter 1130A is configured to deliver a first stent graft 1132A, which can line the second vessel 1102, disabling valves in the second vessel 1102, occluding branch vessels of the second vessel 1102, etc., for example as described. In Figure 34D, the catheter 1130A has been retracted and another catheter 1130B has been tracked over the guide wire 1118. Figure 34D also shows an example of where the occlusion 1108 in the first vessel 1100 may terminate, which may be useful if another fistula was formed between the first vessel 1100 and the second vessel 1102 (e.g., to bypass the occlusion 1108). Forming a second fistula may be the same or different than forming the first fistula (e.g., using at least one of the ultrasound guidance, extending a needle, and prosthesis deployment described herein). In Figure 34E, the catheter 1130B is delivering a second stent graft 1132B, which may at least partially overlap the first stent graft 1132A in an area 1133. In some embodiments, the distal end of the second stent graft 1132B may be configured to overlap the proximal end of the first stent graft 1132A. In some embodiments, the proximal end of the first stent graft 1132A may be configured to be overlapped by the distal end of the second stent graft 1132B. In some embodiments, for example if the second stent graft 1132B is placed first, the proximal end of the first stent graft 1132A may be configured to be 2026223262   27 Aug 2026 overlapped by the distal end of the second stent graft 1132B. The second stent graft 1132B may be longitudinally spaced from the first stent graft 1132A, for example if the longitudinal spacing is small enough that there is unlikely to be a branch vessel and / or a valve in the location of the spacing.

[0512] In Figure 34F, the second stent graft 1132B at least partially overlaps the prosthesis 1124. In some embodiments, the proximal end of the second stent graft 1132A may be configured to overlap the distal end of the prosthesis 1124. In some embodiments, the distal end of the prosthesis may be configured to be overlapped by the proximal end of the second stent graft 1132B. The second stent graft 1132B may be longitudinally spaced from the prosthesis 1124, for example if the longitudinal spacing is small enough that there is unlikely to be a branch vessel and / or a valve in the location of the spacing. Figure 34F also shows the catheter 1132B retracted out of the vasculature. Although two stent grafts 1132A, 1132B are described in this example, one, two, three, or more stent grafts may be used, for example depending on the length of the second vessel 1102 distal to the prosthesis 1124, the length(s) of the stent graft(s), the likelihood or existence of branch vessels, etc.

[0513] Figure 35A shows the second vessel 1102 distal to the first stent graft 1132A. The second vessel 1102 comprises a first valve 1105 A that inhibits or prevents blood 1111 from flowing distal to the first valve 1105A. In Figure 35B, a catheter 1140 is tracked over the guidewire 1118 towards the first valve 1105A through the stent graft H32A. The catheter 1140 comprises a valve disabling device. In Figure 35C, the catheter 1140 is shown as comprising a reverse valvulotome 1142, for example as described herein, and a sheath 1144. Referring again Figure 35B, when the reverse valvulotome 1142 is in the sheath 1144, the reverse valvulotome 1142 is in a radially contracted state. As shown in the Figure 35C, when the sheath 1144 is proximally retracted and / or the reverse valvulotome 1142 is distally-advanced, the reverse valvulotome 1142 radially expands to a state configured to cut valves upon distal advancement. In Figure 35D, the blade or blades of the reverse valvulotome 1142 ablate or cut or sever the leaflets of the first valve 1105A, allowing blood 1111 to flow distal to the first valve 1105A.

[0514] Referring to Figure 35E, after the first valve 1105A has been disabled, the reverse valvulotome 1142 may be radially compressed in the outer sheath 1144 for further distal advancement without affecting the second vessel 1102, As shown in Figure 35F, when 2026223262   27 Aug 2026 a second valve 1105B is encountered, the reverse valvulotome 1142 may extend from the sheath 1144 and then distally advanced to disable the second valve 1105B, allowing the blood 1111 to flow distal to the second valve 1105B. The use of the reverse valvulotome 1142 may be repeated for as many valves in the second vessel 1102 as desired by the user. In some embodiments, a reverse valvulotome 1142 may be used before placement of stent grafts 1132A, 1132B. Valve disabling devices other than a reverse valvulotome, for example but not limited to the two-way valvulotome 1300 as described herein, may also or alternatively be used.

[0515] Figures 36A through 36D illustrate method of promoting retroperfusion of blood through a vein into toes. In Figure 36A, the vasculature illustrated includes a lateral plantar vein 1200, a deep plantar venous arch 1202, metatarsal veins 1204, and a medial plantar vein 1206. Blood flow through the lateral plantar vein 1200, as illustrated by the arrow 1201, is counter to the normal direction of blood flow, for example due to retroperfusion caused by percutaneous bypass from an artery into a vein upstream of the lateral plantar vein 1200. The blood continues to flow through the vasculature as shown by the arrows 1203, where the blood is joined by blood flowing away from the toes in the normal direction of blood flow'through the metatarsal veins 1204, as indicated by the arrow's 1205. The medial plantar vein 1206 is configured to return blood towards the heart, so normal blood flow, as indicated by the arrow 1207, is maintained. Blood may preferentially flow as illustrated in Figure 36A, which is not desirable when the intended effect of the retroperfusion is to perfuse oxygenated blood to the toes.

[0516] Figure 36B illustrates an example embodiment of a device that can be used to promote blood flow to the toes through the metatarsal veins 1204. A first catheter 1210 comprising a first expandable member 1212 (e.g., balloon) may comprise a 6 French occlusion catheter comprising a three-way fitting. The expandable member 1212 is inflated in the lateral plantar vein 1200. A second catheter 1220 that is coaxial with the first catheter 1210 extends through the expandable member 1212, through the deep plantar venous arch 1202, and into the medial plantar vein 1206. The second catheter 1220 comprises an expandable member 1222 (e.g., balloon), which may be inflated in the medial plantar vein 1206. At that point, the medial planar vein 1206 is partially or fully occluded, and blood flow through the medial plantar vein 1206 is inhibited or prevented. Blood may continue to flow' 2026223262   27 Aug 2026 from the toes through the metatarsal veins 1204, as indicated by the persistence of the arrows 1205. The blood has no exit route, so hydrostatic pressure may build up in the deep plantar venous arch 1202, which can disable valves and / or other structures configured to promote normal blood flow. Optionally, the first expandable member 1212 may permit retroperfusion blood to flow, which can further build pressure in the deep plantar venous arch 1202. Blood flow would normally perfuse opposite to the direction of the retroperfusion in the lateral plantar vein 1200, but the expandable member 1212 can inhibit or prevent such flow.

[0517] In some embodiments, a device comprising a single catheter may be used to promote blood flow to the toes through the metatarsal veins 1204. The device may comprise a first expandable member and a second expandable member. For example, the device can comprise a double balloon catheter having a first balloon and a second balloon distal to the first balloon.

[0518] The device may allow one of the first and second expandable members to inflate independently of the other expandable member. For example, in some embodiments, the device may comprise at least a first lumen and a second lumen. The first lumen can be configured to inflate the first expandable member independently of the second expandable member. The second lumen can be configured to inflate the second expandable member independently of the first expandable member. The device may comprise a single lumen configured to inflate both the first and second expandable members. The device may include one or more inflation ports configured to inflate at least one of the first and second expandable members.

[0519] The device may be configured to adjust the distance between the expandable members prior to inflation of at least one of the expandable members. The device may permit the expandable members to isolate a patient-specific treatment area and promote retroperfusion of blood through a vein into toes, as described herein. For example, the device may permit the placement of the first expandable member in the lateral plantar vein 1200 and placement of the second expandable member in the medial plantar vein 1206, and / or vice versa. The device may comprise one or more handles configured to control the movement of various portions of the device. For example, the device may comprise a first handle to control the movement of both the first and second expandable members. In some embodiments, the device may comprise a second handle configured to control the movement of the first 2026223262   27 Aug 2026 expandable member independently of the second expandable member. The second handle may allow the device to advance the first expandable member in a proximal direction relative to the second expandable member from a first position to a second position. After the first expandable member has been advanced to a second position, the second handle may allow the device to advance the first expandable member in a distal direction to the first position.

[0520] The device may comprise an infusion port configured to inject fluid into a treatment area defined by the first and second expandable members. For example, the treatment area may comprise the deep plantar venous arch 1202. After the first and second expandable members have been inflated, blood flow through the medial plantar vein 1206 is inhibited or prevented. The infusion port may then allow the device to inject fluid into the treatment area. The injection of fluid can increase hydrostatic pressure within the treatment area. The hydrostatic pressure increases due to the inflated first and second expandable members preventing the injected fluid from flowing outside the treatment area through the medial plantar vein 1206 and / or the lateral plantar vein 1200. The infusion port can be configured to sufficiently increase in hydrostatic pressure within the treatment area to allow the device to disable valves and / or other structures. For example, the infusion port may be sized to inject an amount of fluid sufficient to increase the hydrostatic pressure to promote blood flow to the toes.

[0521] In Figure 36C, blood flow is allowed through the expandable member 1212, as shown by the arrow 1201, but the inflatable member 1212 inhibits normal blood flow in the deep plantar venous arch 1202, Pressure due to the restricted flow builds up in the deep plantar venous arch 1202. The pressure buildup, optionally in combination with the flow of blood from the lateral plantar vein 1200, can causes reversal of blood flow into the metatarsal veins 1204, as shown by the arrows 1209.

[0522] In Figure 36D, the first catheter 1210 and the second catheter 1220 are removed. The disabling of the normal vasculature in the deep plantar venous arch 1202 causes continued retroperfusion of blood through the metatarsal veins 1204, as shown by the maintenance of the arrow's 1209. A small amount of oxygenated blood may flow through the medial plantar vein 1206. In some embodiments, the medial plantar vein 1206 may remain occluded using the expandable member 1222 (e.g., detachable from the catheter 1220) or a 2026223262   27 Aug 2026 different occluder. In some embodiments, blood may flow through the plantar vein 1206 in a direction opposite normal blood flow.

[0523] Figure 37A illustrates an example of a valve disabling device 1300 in a radially expanded state. The valve disabling device 1300 is configured to cut or ablate or sever or disable leaflets of a valve (e.g., a venous valve) upon retraction and / or advancement in a radially expanded state. The valve disabling device 1300 comprises a proximal portion 1308, a distal portion 1306, and intermediate portion 1302 between the proximal portion 1308 and the distal portion 1306. The proximal portion 1308 comprises a tubular element. The distal portion 1306 comprises a tubular portion. The device 1300 may be formed by cutting (e.g., laser cutting) a hypotube, cutting a flat sheet and rolling into a hypotube, forming parts of the device 1300 and then coupling the parts together, shape setting, combinations thereof, and the like. The tubular element of the distal portion 1306 and / or the tubular element of the proximal portion 1308 may comprise an uncut portion of a hypotube or sheet.

[0524] The proximal portion 1308 may be coupled to a pusher element 1320. The pusher element may comprise a lumen, for example configured to advance across a guidewire. The device 1300 may be in a radially compressed state when confined in a sheath 1304 and in a radially expanded state when not confined in the sheath 1304. The device 1300 may be radially expanded by proximally retracting the sheath 1304 and / or by distally advancing the pusher element 1320 and thereby the device 1300. The device 1300 may be radially compressed by distally advancing the sheath 1304 and / or by proximally retracting the pusher element 1320 and thereby the device 1300. In the radially expanded state, the intermediate portion 1302 may radially expand while the proximal portion 1308 and the distal portion 1306 do not radially expand (e.g,, as shown in Figure 37A).

[0525] The intermediate portion 1302 may comprise cut portions of a hypotube or sheet. The intermediate portion 1302 may comprise one or more struts 1316 extending between the proximal portion 1308 and the distal portion 1306. The intermediate portion 1302 may comprise between about one strut and about eight struts (e.g., one strut, two struts, three struts (e.g., as shown in Figure 37A), four struts, five struts, six struts, seven struts, eight struts, ranges between such values, etc.). The struts 1316 may be approximately equally circumferentially spaced, for example to provide uniform cutting in any circumferential 2026223262   27 Aug 2026 orientation. For example, three struts 1316 may be circumferentially spaced by about 120°. The struts 1316 may unequally circumferentially spaced, for example to provide more cutting in a certain circumferential area. For example, a first strut 1316 may be circumferentially spaced from a second strut 1316 by about 135° and spaced from a third strut 1316 by about 135°, and the second strut 1316 may be spaced from the third strut 1316 by about 90°.

[0526] The strut 1316 may comprise between about one and about four blades (e.g., one blade, two blades (e.g., as shown in Figure 37A), three blades, four blades, ranges between such values, etc.). The strut 1316 shown in Figure 37A comprises a first blade 1312 and a second blade 1314. The first blade 1312 faces proximally and is configured to cut as the device 1300 is proximally retracted. The second blade 1314 faces distally and is configured to cut as the device 1300 is distally advanced. The proximally facing blades 1312 and the distally facing blades 1314 allow the device 1300 to disable a valve when proximally retracted and / or when distally advanced, providing flexibility as a two-way valvulotome. Other configurations are also possible. For example, a first strut 1316 may comprise a proximally facing blade 1312 and a second strut 1316 may comprise a distally facing blade 1314. For another example, a first strut 1316 may comprise a plurality7 of proximally facing blades 1312 and a second strut 1316 may comprise a plurality7 of distally facing blades 1314. For another example, a first strut 1316 may comprise a proximally facing blade 1312 and a distally facing blade 1314 and a second strut 1316 may7 comprise zero blades or be free of or devoid of blades. For another example, a first strut 1316 may comprise a proximally facing blade 1312 and a distally facing blade 1314 and a second strut 1316 may comprise a distally facing blade 1314. For another example, a first strut 1316 may comprise two proximally facing blades 1312 and a distally facing blade 1314.

[0527] Figure 37B is a flattened side view of the valve disabling device 1300 of Figure 37A. The device 1300 may be cut from a flat sheet that is rolled into a hypotube. Figure 37B provides an example cut pattern that may be used to form the device 1300. The cut pattern shown in Figure 37B may also be on a round hypotube. Figure 37B provides some example dimensions of the device 1300. The length 1340 of the distal portion 1306 may be between about 0.1 mm and about 3 mm (e.g., about 0.1 mm, about 0.5 mm, about 1 mm, about 1.5 mm, about 2 mm, about 3 mm, ranges between such values, etc.). The distal potion 1306 may have a length 1340 configured to provide a stable joint for the distal ends of 2026223262   27 Aug 2026 the struts 1316. The circumferential length 1342 of the distal portion 1306 may be between about 1.5 mm and about 5 mm (e.g., about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 5 mm, ranges between such values, etc.). The circumferential length 1342 of the distal portion 1306 may correspond to a circumference of a hypotube used to form the disabling device 1300 or an expansion thereof. The length 1344 of the space between struts 1316 may be between about 0.1 mm and about I mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, ranges between such values, etc.). The length 1344 of the space between struts 1316 may be between about 2% and about 67% of the circumferential length 1340 of the distal portion 1306 (e.g., about 2%, about 5%, about 10%, about 15%, about 20%, about 25%, about 35%, about 50%, about 67%, ranges between such values, etc.). The circumferential thickness 1346 of the struts 1316 maybe between about 0.1 mm and about 1 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, ranges between such values, etc.). The circumferential thickness 1346 of the struts 1316 may be between about 2% and about 67% of the circumferential length 1340 of the distal portion 1306 (e.g., about 2%, about 5%, about 10%, about 15%, about 20%, about 25%, about 35%, about 50%, about 67%, ranges between such values, etc.). Thicker struts 1316 and / or less spacing between the struts 1316 may provide more rigidity and cutting than thinner struts 1316. Thinner struts 1316 and / or more spacing between the struts 1316 may use less force for radial expansion and / or retraction. If the spaces between the struts 1316 have rounded proximal edges, the radius of curvature 1350 at the interface between the proximal portion 1308 and the intermediate portion 1302 may be between about 0.1 mm and about 0.5 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, ranges between such values, etc.). If the spaces between the struts 1316 have rounded distal edges, the radius of curvature at the interface between the distal portion 1306 in the intermediate portion may be between about 0.1 mm and about 0.5 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 ram, about 0.4 mm, about 0.5 mm, ranges between such values, etc.). The radii of curvature at the proximal and distal interfaces may be the same or different. Rather than a radius of curvature, the struts 1316 could meet the proximal portion 1308 and / or the distal portion 1306 at angle. The length 1348 of the proximal portion 1308 may be between about 0.1 mm and about 8 mm 2026223262   27 Aug 2026 (e.g., about 0.1 mm, about 0.5 mm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 8 mm, ranges between such values, etc.). The proximal potion 1308 may have a length 1348 configured to provide a stable joint for the proximal ends of the struts 1316. The proximal potion 1308 may have a length 1348 configured to be coupled to the pusher element 1320. The circumferential length of the proximal portion 1308 may correspond to a circumference of a hypotube used to form the disabling device 1300 or an expansion thereof. The circumferential length of the proximal portion 1308 may be the same or different then the circumferential length 1342 of the distal portion 1306. For example, if the device 1300 is cut from a hypotube and the proximal portion 1308 and the distal portion 1306 comprise uncut portions of the hypotube, the proximal portion 1308 and the distal portion 1306 may have the same circumferential length, or one may be expanded relative to the other (e.g., due to a shape setting process, expansion by outward force of a pusher element 1320, etc.).

[0528] Figure 37C is an expanded view of the flattened side view of the valve disabling device 1300 of Figure 37A in the area identified by the circle 37C in Figure 37B. Figure 37C shows some example dimensions of the device 1300. The radius of curvature 1356 of the blade 1314 may be between about 0.1 mm and about 1 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, ranges between such values, etc.). The distance 1358 between an edge of the blade 1314 and a strut 1316 may be between about 0.1 mm and about 2 mm (e.g., about 0.1 ram, about 0.25 mm, about 0.5 mm, about 0.75 mm, about 1 mm, about 1.25 mm, about 1.5 mm, ranges between such values, etc.). The combined thickness 1360 of a strut 1316 and blade may be between about 0.1 mm and about 3 mm (e.g,, about 0.1 mm, about 0.5 mm, about 1 mm, about 1.5 mm, about 2 mm, about 3 mm, ranges between such values, etc.). The dimensions of the blade 1312 on the strut 1316 of Figure 37C maybe the same or different than the dimensions of the blade 1314 in Figure 37C. The dimensions of the other blades 1314 may be the same or different than the dimensions of the blade 1314 in Figure 37C.

[0529] Figure 37D is an end view of the valve disabling device 1300 of Figure 37A flattened as shown in Figure 37B. Figure 37D shows some example dimensions of the device 1300. The thickness 1362 may be between about 0.05 mm and about 0.25 mm (e.g., 2026223262   27 Aug 2026 about 0.05 mm, about 0.1 mm, about 0.15 mm, about 0.2 mm, about 0.25 mm, ranges between such values, etc.). A greater thickness 1362 may provide more rigidity and cutting force. A smaller thickness 1362 may use less force for radial expansion and / or retraction. If the device 1300 is formed from a hypotube, the thickness 1362 maybe a difference between an inner diameter of the hypotube and an outer diameter of the hypotube, or the thickness of the hypotube wall. The circumferential distance 1342, as described above, may be about 1.5 mm and about 5 mm (e.g., about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 5 mm, ranges between such values, etc.).

[0530] Figure 37E is an end view of the valve disabling device 1300 of Figure 37A in a radially contracted state. Figure 37 shows some example dimensions of the device 1300 in a radially contracted state. The outer diameter 1352 may be between 0.6 mm and about 1.5 mm (e.g., about 0.6 mm, about 0.8 mm, about 1 mm, about 1.2 mm, about 1.5 mm, ranges between such values, etc.). The outer diameter 1352 is greater than the inner diameter 1354. The inner diameter 1354 may be between about 0.5 mm and about 1.4 mm (e.g., about 0.5 mm, about 0.75 mm, about 1 mm, about 1.25 mm, about 1.4 mm, ranges between such values, etc.). Referring again to Figure 37D, the thickness 1362 may correspond to the difference between the outer diameter 1352 and the inner diameter 1354, divided by two. For example, if the outer diameter 1352 is 1 mm and the inner diameter 1354 is 0.8 mm, the thickness 1362 would be: (1 mm - 0.8 mm) / 2 = 0.1 mm.

[0531] Figure 37F is a side view of the valve disabling device 1300 of Figure 37A in a radially contracted state. Figure 37G is another side view of the valve disabling device 1300 of Figure 37A in a radially contracted state and circumferentially rotated compared to Figure 37F. Figures 37F and 37G show some example dimensions of the device 1300 in a radially contracted state. The length 1364 between a distal end of the distal portion 1306 and a proximal end of the proximal portion 1308 may be between about 15 mm and about 27 mm (e.g., about 15 mm, about 18 mm, about 21 ram, about 24 mm, about 27 mm, ranges between such values, etc.). Referring again to Figure 37B, the length 1340 of the distal portion 1306 and the length 1348 of the proximal portion 1308 may be subtracted from the length 1364 to calculate the length of the intermediate portion 1302. The length 1366 between an edge of the blade 1314 and a distal end of the proximal portion 1308 may be between about 5 mm and about 10 mm (e.g., about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 2026223262   27 Aug 2026 10 mm, ranges between such values, etc.). The length 1366 may affect and / or be based on a diameter of the blade 1314 in a radially expanded state.

[0532] Figure 37H is a side view of the valve disabling device 1300 of Figure 37A in a radially expanded state. Figure 371 is another side view of the valve disabling device 1300 of Figure 37A in a radially expanded state and circumferentially rotated compared to Figure 37H. Figures 37H and 37G show some example dimensions of the device 1300 in a radially expanded state. The radially expanded state shown in Figures 37H and 37G may be fully expanded (e.g., the shape of the device 1300 absent external forces) or a partially radially expanded state. The length or radius 1368 between a longitudinal axis 1367 through a center of the device 1300 and outer circumference of an expanded intermediate portion 1302 may be between about 0.5 mm and about 7 mm (e.g., about 0.5 mm, about 1 mm, about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, ranges between such values, etc.). A length 1370 between a distal end of the distal portion 1306 and a proximal end of the proximal portion 1308 may be between 10 mm and about 25 mm (e.g., about 10 mm, about 15 mm, about 18 mm, about 20 mm, about 22 mm, about 25 mm, ranges between such values, etc.). Referring again to Figure 37F, the length 1364 in a radially contracted state may be longer than the length 1370 in the radially expanded state. The difference between the length 1370 and the length 1364 may be between about 0.1 mm and about 1 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1 mm, ranges between such values, etc.). Referring again to Figure 37B, the length 1340 of the distal portion 1306 and the length 1348 of the proximal portion 1308 maybe subtracted from the length 1370 to calculate the length of the intermediate portion 1302 in a really expanded state. The length 1372 between a tip of a first blade 1314 and a second blade 1314, taken transverse to the longitudinal axis 1367 of the device 1300, may be between about 2 mm and about 4 mm (e.g., about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, ranges between such values, etc.).

[0533] Figure 37J is a cross-sectional end view of the valve disabling device 1300 of Figure 37A in a radially expanded state taken along the line 37J-37J of Figure 37H. Figure 37J shows that the blades 1314 maybe rotated relative to the struts 1316, as indicated by the arrows 1321. Each blade 1314 may be rotated the same amount and in the same direction, or 2026223262   27 Aug 2026 different blades 1314 may be rotated in different amounts and / or in different directions. The blades 1312 may also be rotated the same way and / or in a different way (e.g., opposite) than as shown for the blades 1314 in Figure 37J.

[0534] Figures 37Ki through 37Nii illustrate example procedures that can be performed using the valve disabling device 1300 of Figure 37A. The procedures are not mutually exclusive and maybe performed based on, for example, user preference, anatomy, vessel access point, other procedure(s) being performed, combinations thereof, and the like.

[0535] Figure 37Ki shows a device 1300 being tracked through a vessel 1301 having a valve 1305. The device 1300 may be tracked over a guidewire 1318 that has been navigated through the valve 1305. The device 1300 may be advanced over the guidewire 1318 in a radially contracted state, with the intermediate portion 1302 collapsed in the sheath 1304. In Figure 37Kii, the sheath 1304 is retracted, as indicated by the arrow 1323, which allows the intermediate portion 1302 to radially expand, as shown by the arrows 1325. The device 1300 may then be distantly advanced, as shown by the arrow 1327. The distally facing blades 1314 may interact with the valve 1305 to cut or ablate or disable the leaflets of the valve 1305. The intermediate portion 1302 may be really compressed by proximally retracting the device 1300 into the sheath 1304 and / or by distally advancing the sheath 1304 over the device 1300. The device 1300 may then be used to disable another valve or withdrawn as desired.

[0536] Figure 37Li shows a device 1300 tracked through the cavity a vessel 1301 including a valve 1305. The device 1300 has been advanced distal to the valve 1305 in a radially contracted state over the guidewire 1318. In Figure 37Lii, the sheath 1304 is proximally retracted, as indicated by the arrow 1323, which allows the intermediate portion 1302 of the device 1300 to radially expand, as shown by the arrows 1325. The device 1300 may then be proximally retracted, as shown by the arrow 1329, which allows the proximally facing blade 1312 to disable the valve 1305. The intermediate portion 1302 may be really compressed by proximally retracting the device 1300 into the sheath 1304 and / or by distally advancing the sheath 1304 over the device 1300. The device 1300 may then be used to disable another valve or withdrawn as desired.

[0537] Figure 37Mi shows a device 1300 being tracked through a vessel 1301 having a valve 1305. The device 1300 may be tracked over a guidewire 1318 that has been 2026223262   27 Aug 2026 navigated through the valve 1305. The device 1300 may be advanced over the guidewire 1318 in a radially contracted state, with the intermediate portion 1302 collapsed in the sheath 1304. In Figure 37Mii, the sheath 1304 is retracted, as indicated by the arrow'" 1323, which allows the intermediate portion 1302 to radially expand, as shown by the arrows 1325. The device 1300 may then be distantly advanced, as shown by the arrow 1327. The distally facing blades 1314 may interact with the valve 1305 to cut or ablate or disable the leaflets of the valve 1305. The intermediate portion 1302 may be really compressed by proximally retracting the device 1300 into the sheath 1304 and / or by distally advancing the sheath 1304 over the device 1300. The device 1300 may then be used to disable another valve or withdrawn as desired. Compared to Figures 37Ki and 37Kii, the method shown in Figures 37M1 and 37Mii is from an opposite direction. One direction may be upstream and the other direction may be downstream. One direction may be in the direction of normal blood How' and the other direction may be the direction of blood flow after retroperfusion.

[0538] Figure 37Ni shows a device 1300 tracked through the cavity a vessel 1301 including a valve 1305. The device 1300 has been advanced distal to the valve 1305 in a radially contracted state over the guidewire 1318. In Figure 37Nii, the sheath 1304 is proximally retracted, as indicated by the arrow 1323, which allows the intermediate portion 1302 of the device 1300 to radially expand, as shown by the arrows 1325. The device 1300 may then be proximally retracted, as shown by the arrow' 1329, which allows the proximally facing blade 1312 to disable the valve 1305. The intermediate portion 1302 may be really compressed by proximally retracting the device 1300 into the sheath 1304 and / or by distally advancing the sheath 1304 over the device 1300. The device 1300 may then be used to disable another valve or withdrawn as desired. Compared to Figures 37Li and 37Lii, the method shown in Figures 37Ni and 37Nii is from an opposite direction. One direction may be upstream and the other direction may be downstream. One direction may be in the direction of normal blood flow and the other direction may be the direction of blood flow after retroperfusion.

[0539] Figure 38A schematically illustrates an example of a distal end of a catheter 1400. The catheter 1400 may include an ultrasound transducer or other targeting device. The catheter 1400 may be used in a second vessel (e.g. a vein) that can be targeted by another catheter (e.g., comprising an ultrasound transducer) in a first vessel. The distal end of 2026223262   27 Aug 2026 the catheter 1400 comprises a capture element 1404 having a funnel shape extending distal to a tubular element 1402. The capture element 1404 may extend out the tubular element 1402, for example due to an actuation mechanism coupled to the handle and the capture element 1404, by comprising shape memory material configured to assume a predetermined shape upon undergoing a phase change due to temperature (e.g., due to body temperature versus room temperature), due to expansion by an expandable member (e.g., an inflatable balloon), and / or other mechanisms. The capture element 1404 may have an angle between about 90° and about 170° (e.g., about 90°, about 110°, about 130°, about 150°, about 170°, ranges between such values, etc.). The tubular member 1402 may comprise a lumen 1408 extending at least partially therethrough for guiding a guidewire captured by the capture element 1404 through the catheter 1400. Guiding a guidewire through the catheter 1400 can ensure that the guidewire is advanced through the same vessel(s) as the catheter 1400, rather than through unintended branch or collateral vessels. The lumen 1408 may comprise an expanded portion 1409 that is internal to the tubular member 1402.

[0540] Figures 38B through 38D illustrate an example procedure that can be performed using the distal end of the catheter 1400 of Figure 38A. Figure 38B is similar to Figure 32D in that a needle 1016 has passed from a first vessel 1000, through interstitial tissue, and into a second vessel 1002. The catheter 1400 of Figure 38A is in the second vessel 1002. The catheter 1400 may have been proximally retracted, for example as indicated by the arrow 1403, after being successfully targeted by the catheter 1010 in the first vessel 1000. The distance of retraction of the catheter 1400 after successful targeting may be predetermined (e.g,, based on a distance between the distal end of the catheter 1400 and a transducer of the catheter 1400) and / or maybe based on user experience, fluoroscopy, combinations thereof, and the like. In Figure 38C, the capture element 1404 has expanded out of the distal end of the catheter 1400. The capture element 1404 can act as a funnel to guide a guidewire extending out of the needle 1016 into the catheter 1400. In Figure 38D, a guidewire 1406 extends out of the needle 1016, for example as described herein, is captured by the capture element 1404, and then is guided by the portion 1409 into the lumen 1408. The guidewire 1406, further distally advanced, wall extend further into the lumen 1408, as opposed to any chance of the guidewire 1406 extending through the branch vessel 1006 and / or other branch vessels. Procedures performed by tracking over the guidewire 1406 (e.g., 2026223262   27 Aug 2026 valve disabling, graft placement, balloon expansion, etc.), can ensure that such procedure will be performed in the intended vessels, which can provide better and more predictable retroperfusion.

[0541] Figures 38Ei and 38Eii illustrate an example of a distal end of a catheter 1440. The catheter 1440 may be similar to the catheter 1400. The catheter 1440 includes an inflation lumen 1445 and an expandable member 1446 (e.g., comprising a balloon). When the catheter 1440 is it an appropriate position, for example as illustrated in Figure 38B, an expandable member 1444 may be expanded, and the capture element 1444 may be expanded by the expandable member 1446. Compared to Figure 38Ei, Figure 38Eii shows the expandable member 1446 slightly distally advanced and then in expanded in order to push the capture element 1444 radially outward. The expandable member 1446 may be positioned and / or shaped to expand the capture element 1444 without being distally advanced. As described above, other methods of expanding a capture element 1444 are also possible.

[0542] Figure 38F illustrates an example of a portion of a catheter 1420. The catheter 1420 comprises an ultrasound transducer 1422. The catheter 1420 comprises a capture element 1424 that extends out a side of the catheter 1420. The capture element 1424 may comprise a funnel leading to a lumen 1428, which may optionally comprise an expanded portion 1429. The capture element 1424 is configured to capture a guidewire 1406 and guide the guidewire 1406 into the lumen 1428. The capture element 1424 may be located proximate to the transducer 1422. In accordance with certain targeting systems described herein, the needle 1016 may extend towards the transducer 1422 such that he guidewire 1406 extending out of the needle 1016 would be proximate to the transducer 1422, and thus proximate to the capture element 1424. The capture element 1424 may be proximal to the transducer 1422.

[0543] Figure 38G illustrates another example of a portion of a catheter 1430. The catheter 1430 comprises a transducer 1422. The catheter 1430 comprises a capture element 1434 that extends out a side of the catheter 1430. The capture element 1434 may comprise a partial funnel leading to a lumen 1438, which may optionally comprise an expanded portion 1439. The capture element 1434 may extend partially or fully around a circumference of the catheter 1430. The capture element 1434 is configured to guide a guidewire 1406 into a lumen 1438, which may include an expanded portion 1439. The 2026223262   27 Aug 2026 capture element 1434 may comprise, for example, a portion of the catheter 1430 that is deformed upon reaching body temperature to open an aperture to lumen 1438 as the capture element 1434 expands. The capture element 1434 may be configured to appose a sidewall of a vessel in which the catheter 1430 resides. The features of the catheters 1400, 1420, 1430, 1440 may be combined with the features of the catheter 1020 or other catheters described herein.

[0544] Figure 39A is a perspective view of an example of a portion of a target catheter 1500. The target catheter 1500 comprises a sheath 1502 and an expandable structure 1504. The expandable structure 1504 comprises a collapsed state and an expanded state. Figure 39A shows the expandable structure 1504 in the expanded state. The expandable structure 1504 comprises a plurality of struts that taper towards the proximal end 1506 in the expanded state. The struts form a plurality of cells. In some examples, a guidewire sheath 1508 extends through the sheath 1502 and the expandable structure 1504. The target catheter 1500 may be tracked over a first guidewire extending through the guidewire sheath 1508.

[0545] Figure 39B is a side view of the target catheter 1500 of Figure 39A in a first state. The first state may be considered a closed state or a delivery' state. In the first state, the expandable structure 1504 is in the collapsed state in the sheath 1502. In some examples, the guidewire sheath 1508 protrudes out of the distal end of the sheath 1502. A proximal end of the target catheter may include flush ports, guidewire ports, and / or the like. A distal end of the catheter may include a targeting sensor (e.g., an ultrasound receiver), a diagnostic sensor (e.g., a pressure sensor), combinations thereof, and / or the like. In some examples, a targeting sensor is proximal to the expandable structure 1504 in the collapsed state and / or in the expanded state. In some examples, a targeting sensor is distal to the expandable structure 1504 in the collapsed state and / or in the expanded state. In some examples, a targeting sensor is longitudinally between a proximal end of the expandable structure 1504 and a distal end of the expandable structure 1504 in the collapsed state and / or in the expanded state.

[0546] Figure 39C is a side view of the target catheter 1500 of Figure 39A in a second state. The second state may be considered an open state or a deployed state. The expandable structure 1504 can be deployed from the sheath 1502 by distally advancing the expandable structure 1504 and / or proximally retracting the sheath 1502. Figure 39C show's the relative movement between the sheath 1502 and the expandable structure 1504 by the 2026223262   27 Aug 2026 arrow 1510 and the corresponding radial expansion of the expandable structure 1504 by the arrows 1512. In some examples, the expandable structure 1504 is self-expanding (e.g., comprising a shape-memory material such as nitinol) and is able to assume the expanded state when not confined by the sheath 1502. The expandable structure 1504 can be retrieved in the sheath 1502 by distally advancing the sheath 1502 and / or proximally retracting the expandable structure 1504.

[0547] Figures 39D-39I schematically illustrate an example method of using the target catheter 1500 of Figure 39A. In Figure 39D, a first catheter 1010 is advanced in a first vessel 1000 comprising an occlusion, for example as described herein. The target catheter 1500 is advanced in a second vessel 1002. For example, the target catheter may be tracked over a first guideware that has been advanced through the second vessel 1002. The distal end of the sheath 1502 may be longitudinally proximate to the occlusion. In Figure 39E, the expandable structure 1504 is radially expanded, as shown by the arrows 1514. In some examples, expansion of the expandable structure 1504 radially expands the vessel 1002, as shown by the arrows 1516. Expanding the vessel 1002 can increase the target for a needle extending from the first catheter 1010. In some examples in which the second vessel 1002 is a vein, expanding the vessel 1002 can keep the vein open, which can avoid influence of potential or eventual spasm.

[0548] In Figure 39F, a needle 1016 extends from the first catheter 1010 out of the first vessel 1000, through interstitial tissue, and into the second vessel 1002. In the second vessel 1002, the needle 1016 extends between the proximal end of the expandable structure 1504 and the distal end of the expandable structure 1504. The needle 1016 may extend through a cell of the expandable structure 1504. If the needle 1016 initially contacts a strut of the expandable structure 1504, the strut may be deflected such that the needle 1016 extends through a cell. The tip of the needle 1016 does not necessarily need to pierce the center of the second vessel 1010 because, even if the second vessel 1002 is pierced at an angle, the needle 1016 can extend into the expandable structure 1504 at an angle, and a subsequently deployed second guidewire 1406 can be snared by the expandable structure 1504. The extension of the needle 1016 may be guided using a targeting system (e.g., a directional ultrasound targeting system, for example as described herein). In some examples, the needle may be extended towards the expandable structure 1504, for example using fluoroscopy with or without a 2026223262   27 Aug 2026 targeting system. In certain such examples, the expandable structure 1504 may comprise radiopaque markers and / or the material of the expandable structure 1504 may be radiopaque (e.g., the expandable structure may comprise radiopaque fluid in an expanded (e.g., inflated) stated).

[0549] In Figure 39G, a second guidewire 1406 is advanced through the first catheter 1010 and the needle 1016 into the second vessel 1002. Because the needle 1016 extends into the expandable structure 1504, the second guidewire 1406 extends into the expandable structure 1504. In Figure 39H, the expandable structure 1504 is collapsed, for example by at least partially retracting the expandable structure 1504 into the sheath 1502. Collapsing the expandable structure 1504 grabs or snares the second guidewire 1406. In some examples, the expandable structure 1504 may optionally be twisted or torqued to help snare the second guidewire 1406. In Figure 391, the target catheter 1500 is proximally retracted. Because the second guidewire 1406 is snared by the expandable structure 1504, the second guidewire 1406 is advanced through the second vessel 1002, for example during removing the target catheter 1500 from the second vessel 1002. Catheters comprising a valvulotome, a stent-graft, and the like may be tracked over the second guidewire 1406 and through the second vessel 1002, for example as described herein.

[0550] Figure 40A is a perspective view of an example handle 1600 for deploying a tubular structure. The tubular structure may comprise a stent such as the stent 1122 or a stent-graft such as the stent-graft 1132. In some examples, the handle 1600 may be used to deploy a valvulotome such as the valvulotome 1142, 1300, an expandable structure such as the expandable structure 1504, and the like. The handle 1600 comprises a body 1602 and a knob 1604. The body 1602 comprises a first segment 1606 comprising threads 1607. The body 1602 comprises a second segment 1608 free of threads. A slot 1609 extends from a proximal part of the body 1602 to a distal part of the body 1602,

[0551] Figure 40B is an expanded perspective cross-sectional view of a portion of the handle 1600 of Figure 40A. The knob 1604 comprises threads 1617 configured to interact with the threads 1607. A slider 1610 extends through the slot 1609. The slider 1610 comprises a connector 1612 coupled to an external sheath such that proximal movement of the slider 1610 proximally retracts the external sheath. As the knob 1604 is rotated, the slider 1610 is proximally retracted, which proximally retracts the external sheath. The initial 2026223262   27 Aug 2026 deployment of a tubular structure may need a higher quantity7 of force than later deployment because friction between the tubular structure and the external sheath decreases as the tubular structure is deployed from the external sheath. The threads 1607, 1617 can help to transmit higher force by7 converting rotational force into longitudinal force. Once the knob 1604 is retracted proximal to the threads 1607, the knob 1604 may be proximally pulled, pulling the slider 1610 and thus the external sheath. In some examples, the initial amount of force would be very difficult to effect by proximal pulling but can be accomplished by rotation of the knob 1604. In some examples, rotating the knob 1604 deploys a first amount of the tubular structure and sliding the knob 1604 deploys a second amount of the tubular structure. The first and second amounts total the entire tubular structure. In some examples, the first amount is less than the second amount. For example, the first amount may be between about 10% and about 60% of the second amount (e.g., about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, ranges between such values, and the like).

[0552] In some examples, the transition between the first amount and the second amount corresponds to approximately a peak deployment force. The peak deployment force can vary7 based on, for example, tubular structure design (e.g., length, diameter, radial force, material(s)), outer sheath design (e.g., diameter, material(s), coating(s)), combinations thereof, and the like. In some examples, the transition is at least about one third of the length of the tubular structure. In some examples, the transition is at least about one half of the length of the tubular structure. In some examples, a ratio between the first amount and the second amount can be adjusted by adjusting the threads (e.g., length and / or pitch).

[0553] Figure 40C is a perspective view of the handle 1600 of Figure 40A in a deployed state. Figure 40D is an expanded perspective cross-sectional view of a portion of the handle 1600 of Figure 40A in a deployed state. The knob 1604 has been rotated and then proximally retracted. Distal to the handle 1600, a tubular structure is deployed. For example, a stent may be deployed from a first vessel, through interstitial tissue, and into a second vessel.

[0554] Figure 41A is a perspective view of an example handle 1700 for deploying a tubular structure. The tubular structure may comprise a stent such as the stent 1122 or a stent-graft such as the stent-graft 1132. In some examples, the handle 1700 may be used to deploy a valvulotome such as the valvulotome 1142, 1300, an expandable structure such as 2026223262   27 Aug 2026 the expandable structure 1504, and the like. The handle 1700 comprises a body 1702 and a knob 1704. The body 1702 optionally includes a shell 1716. A slot 1709 extends from a proximal part of the body 1702 to a distal part of the body 1702.

[0555] Figure 41B is an expanded perspective partially transparent view of a portion of the handle 1700 of Figure 41 A. Figure 41B shows the handle 1700 from an opposite side compared to Figure 41A. The knob 1704 is coupled to a gear or worm gear or worm wheel 1706 having teeth 1717 configured to interact with teeth 1707 of a slider member or worm or worm screw' 1710. The body 1702 is fixably coupled to an inner shaft assembly. The slider member 1710 if fixably coupled to an outer sheath. In some examples, the inner shaft assembly has a distal end comprising a plurality of radiopaque marker bands which can make a tubular structure pocket visible. A proximal radiopaque marker fixed to the inner shaft assembly can act as a pusher to maintain the longitudinal position of the tubular structure while an outer sheath is proximally retracted. Movement of the slider member 1710 relative to the body 1702 causes movement of the outer sheath relative to the inner shaft assembly. The slider 1710 comprises a first portion 1712, a second portion 1713, and a third portion 1714. The first portion 1712 is fixably coupled to an outer sheath. The first portion 1712 is inside the body 1702. The second portion 1713 protrudes through the slot 1709. The third portion 1714 is wider than the second portion 1713. The third portion 1714 is outside the body 1702, except in examples including a shell 1716. The user interacts with the third portion 1714 once the slider member 1710 is in position to be proximally pulled. The body 1702 may include two slots 1709, for example circumferentially opposite each other. In certain such examples, the slider member 1710 may include two second portions 1713 and two third portions 1714 (e.g., as illustrated in Figure 41B). Two third portions 1714 may allow a user to grip both sides of the slider member 1710, providing grip that is better than one side. In some examples, the third portion(s) 1714 may comprise features to enhance grip (e.g., textured surfaces, recesses, flanges, etc.).

[0556] Figures 41C to 41Eiii show an example method of operating the handle 1700 of Figure 41A. In Figure 41C, rotation of the knob 1704 causes the gear 1706, including the teeth 1717, to rotate. The teeth 1717 interact with the teeth 1707 of the slider 1710 to convert the rotational force into longitudinal force, proximally retracting the slider member 1710, which proximally retracts an external sheath. The initial deployment of a 2026223262   27 Aug 2026 tubular structure may need a higher quantity of force than later deployment because friction between the tubular structure and the external sheath decreases as the tubular structure is deployed from the external sheath. The shell 1716 may inhibit a user from attempting to proximally retract the slider member 1710 until an amount of the tubular structure is deployed that deploying the remaining amount of the tubular structure does not require a high amount of force. The shell 1716 includes a proximal aperture 1718 that the slider can exit upon proximal retraction.

[0557] In Figure 41Di, the knob 1704 has been rotated until the slider member 1710 is in a proximal position out of the shell 1716. The exposed slider member 1710 may be proximally pulled, thereby pulling the outer sheath. In some examples, the initial amount of force would be very difficult to effect by proximal pulling but can be accomplished by rotation of the knob 1704. Figure 41Dii shows an example tubular structure 1720 being deployed from an example outer sheath 1722. Figure 41Dii shows the positions of the tubular structure 1720 and the outer sheath 1722 after the knob 1704 has been rotated until the slider member 1710 is in a position to be proximally retracted (e.g., out of the shell 1716). A first portion 1724 of the tubular structure 1720 has been deployed from the outer sheath 1722.

[0558] Figure 41Ei is a perspective view the handle 1700 of Figure 41A in a retracted position. Figure 41Eii is a perspective cross-sectional view the handle 1700 of Figure 41A in a retracted position. The slider member 1710 has been proximally retracted to a distal part of the body 1702, proximally retracting the outer sheath by a quantity sufficient to deploy an entire tubular structure. Figure 41Eiii shows the positions of the tubular structure 1720 and the outer sheath 1722 after the slider member 1710 has been proximally retracted to the distal part of the body 1702, A second portion 1726 of the tubular structure 1720 has been deployed from the outer sheath 1722. The first portion 1724 and the second portion 1726 may be an entire length of the tubular structure 1720.

[0559] In some examples, rotating the knob 1704 deploys a first amount of the tubular structure and sliding the slider member 1710 deploys a second amount of the tubular structure. The first and second amounts may total the entire tubular structure. In some embodiments, first and second amounts plus a third amount, a fourth amount, etc. may total the entire tubular structure. The third amount, fourth amount, etc. optionally may be deployed using other features. In some examples, the first amount is less than the second 2026223262   27 Aug 2026 amount. For example, the first amount may be between about 10% and about 70% of the second amount (e.g., about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 70%, ranges between such values, and the like). In some examples, a ratio of the first amount to the second amount is between about 1:5 and about 5:3 (e.g., about 1:5, about 2:5, about 3:5, about 4:5, about 5:5, about 5:4, about 5:3, ranges between such values, and the like).

[0560] With the tubular structure deployed, a catheter coupled to the handle 1700 may be removed from the subject. In some examples in which the tubular structure is coupled to a distal end of the inner shaft assembly, the slider member 1710 may be distally advanced to capture a first portion of the tubular structure. In some examples, capturing the first portion of the tubular structure is an amount that is sufficient to safely remove a catheter coupled to the handle 1700 from the subject. In some examples, the knob 1704 may then be rotated to capture a second portion of the tubular structure.

[0561] Figure 42A is a top view of an example embodiment of a launching device 4200. The launching device 4200 includes a proximal portion 4202 and a distal portion 4204. The distal portion 4204 comprises a catheter 4206. The catheter may have an outer diameter, for example, between about 3 Fr and about 10 Fr (e.g., about 3 Fr, about 4 Fr, about 5 Fr, about 6 Fr, about 7 Fr, about 8 Fr, about 9 Fr, about 10 Fr, ranges between such values, and the like). The catheter 4206 includes a needle lumen 4208. A needle 4216 is configured to extend out of the needle lumen 4208. The proximal portion 4202 includes a handle 4211 and an actuator 4212. When the actuator 4212 is distally advanced and / or the handle 4211 is proximally retracted, the needle 4216 extends out of the needle aperture 4208, for example as described herein with respect to the needle 4216. When the actuator 4212 is proximally retracted and / or the handle 4211 is distally advanced, the needle 4216 retracts back into the needle aperture 4208. Other types of handles or proximal components are also possible. For example, the proximal portion 4202 could comprise an activator switch, lever, knob, etc. such that when the activator is actuated. For another example, the proximal portion 4202 could comprise telescoping elements (e.g., proximal portions of catheters or members coupled thereto) graspable by a user such that the needle 4216 extends out of the needle aperture 4208 upon relative longitudinal movement between the telescoping elements. 2026223262   27 Aug 2026

[0562] The distal portion 4204 comprises a radiopaque marker 4210. The radiopaque marker 4210 comprises a radiopaque material (e.g., tantalum, titanium, nickel, tungsten, platinum, gold, silver, iridium, palladium, tin, zirconium, rhenium, bismuth, molybdenum, barium sulfate, tungsten powder, bismuth subcarbonate, bismuth oxychloride, iodine containing agents such as lohexol (e.g., Ommpaque®, available from Amersham Health, a division of GE Healthcare), combinations thereof, and the like).

[0563] Figure 42B is a schematic top, side, and distal end perspective view of a distal portion 4204 of the launching device 4200 of Figure 42A. The radiopaque marker 4210 comprises a flat rectangular (e.g., square) marker. The radiopaque marker 4210 does not conform to the arcuate outer surface of the catheter 4206. The radiopaque marker 4210 may be rectangular, which can include rectangle, square, having adjacent sides that are about 90° to each other, having at least two opposing sides that are substantially parallel to each other (e.g., parallelogram, trapezoid), and / or the like, whether having sharp or rounded corners. Shapes other than rectangular are also possible, but the radiopaque marker 4210 is preferably thin and flat. The radiopaque marker 4210 may be flat, which can include having a thickness less than a certain amount, for example as described herein. The thickness can be between a highest point and a lowest point when the radiopaque marker 4210 is positioned on a flat surface (e.g., a rounded (e.g., following a contour of an outer surface of a catheter) radiopaque marker would have a higher center point than edge points and should not be considered flat). A flat radiopaque marker 4210 may have a ratio of a thickness to a shortest lateral length between about 1 / 3,000 and about 1 / 3 (e.g., about 1 / 3,000, about 1 / 2,000, about 1 / 1,000, about 1 / 500, about 1 / 250, about 1 / 200, about 1 / 100, about 1 / 50, about 1 / 25, about 1 / 12, about 1 / 10, about 1 / 5, about 1 / 4, about 1 / 3, ranges between such values, and the like). A flat radiopaque marker 4210 may have a ratio of a thickness to a longest lateral length between about 1 / 3,000 and about 1 / 3 (e.g., about 1 / 3,000, about 1 / 2,000, about 1 / 1,000, about 1 / 500, about 1 / 250, about 1 / 200, about 1 / 150, about 1 / 100, about 1 / 50, about 1 / 25, about 1 / 12, about 1 / 10, about 1 / 5, about 1 / 4, about 1 / 3, ranges between such values, and the like). A flat radiopaque marker 4210 may have a thickness such that the radiopaque marker 4210 substantially disappears on fluoroscopy when the radiopaque marker 4210 is perpendicular to the imaging plane. 2026223262   27 Aug 2026

[0564] Figure 42B also shows a length 4230, width 4232, and thickness 4234 of the marker 4210. In some examples, the radiopaque marker 4210 has a length 4230 between about 1 mm and about 3 mm (e.g., about 1 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 5 mm, ranges between such values, and the like). In some examples, the radiopaque marker 4210 has a width 4232 between about 0.25 mm and about 3 mm (e.g., about 0.25 mm, about 0.5 mm, about 1 mm, about 1.5 mm, about 2 mm, about 3 mm, ranges between such values, and the like). In some embodiments, a ratio of the length 4230 to the width 4232 is between about 1 / 1 and about 5 / 1 (e.g., about 1 / 1, about 2 / 1, about 2.5 / 1, about 3 / 1, about 3.5 / 1, about 4 / 1, about 5 / 1, ranges between such values, and the like). In some examples, the radiopaque marker 4210 has a thickness 4234 between about 0.001 mm and about 1 mm (e.g., about 0.001 mm, about 0.002 mm, about 0.003 mm, about 0.005 mm, about 0.01 mm, about 0.015 mm, about 0.02 mm, about 0.025 mm, about 0.03 mm, about 0.05 mm, about 0.075 mm, about 0.1 mm, about 0.15 mm, about 0.2 mm, about 0.25 mm, about 0.3 mm, about 0.5 mm, about 1 mm, ranges between such values, and the like).

[0565] Figure 42Bi is a schematic side view of another example radiopaque marker 4250. The radiopaque marker 4250 may be include the same or similar features as the radiopaque maker 4210, and may be used in the same or similar systems and methods. The radiopaque marker 4250 comprises a first material 4250a making up a bulk of the radiopaque marker 4250 and a second material 4250b coupled to the first material 4250a. In some examples, a radially outward surface of the radiopaque marker 4250 consists of the second material 4250b. The second material 4250b may be more radiopaque than the first material 4250a (e.g., having a difference enough to discern the second material 4250b under fluoroscopy). In some examples, the second material 4250b is radiopaque and the first material 4250a is radiolucent. The second material 4250b can be coupled to the first material 4250a via cladding, plating, chemical vapor deposition, atomic layer deposition, screen printing, coating (e.g., dip coating, spray coating), adhesion, sputtering, etc. In certain such examples, the second material 4250b can be thinner than the bulk of the entire radiopaque marker 4250. The first material 4250a may be polished or otherwise flattened prior to coupling the second material 4250b, for example to increase the flatness of the second material 4250b coupled thereto. Because the second material 4250b is the material used for 2026223262   27 Aug 2026 alignment of the catheter, the second material 4250b (e.g., not the entire radiopaque marker 4250, not the first material 4250a) by itself may be considered the radiopaque marker.

[0566] In some examples, the second material 4250b of the radiopaque marker 4250 has a thickness 4236 that is less than about 2 pm. In some examples, the second material 4250b of the radiopaque marker 4250 has a thickness 4236 between about 1 nm and about 10 pm (e.g., about 1 nm, about 2 nm, about 3 nm, about 5 nm, about 10 nm, about 50 nm, about 100 nm, about 500 nm, about 1 pm, about 2 pm, about 3 pm, about 5 pm, about 10 pm, ranges between such values, and the like). The thickness 4236 of the second material 4250b may depend on the composition of the second material 4250b and / or the coupling technique. For example, a metalized nickel layer may be between about 1 pm and about 2 pm. For another example, a layer of gold may be between about 1 nm and about 5 nm or between about 1 pm and about 3 pm. Other layers of material are also possible. For example, a radiolucent material (e.g., polymer) can be coated over the second material 4250b to inhibit corrosion of the second material 4250b, to allow use of a second material 4250b usually considered non-biocompatible, to follow the contours of the catheter, and / or other reasons. Because the material is radiolucent, the methods described herein are not affected.

[0567] The example dimensions, particularly the thickness, can limit a shadowing effect on angioscopes or x-ray or fluoroscopy machines. As appreciated from the discussion herein, accurate identification of a thin radiopaque marker 4210, 4250 is used for alignment of the catheter 4200. A shadow effect may inhibit a user’s ability to detect thinness.

[0568] The radiopaque marker 4210 is on a side of the catheter 4200, for example as opposed to being along a diameter or a radius. In some embodiments, the radiopaque marker 4210 is on the same side as the needle aperture 4208. In some embodiments, the radiopaque marker 4210 is on an opposite side from the needle aperture 4208. Depending on the position of the radiopaque marker 4210, a goal of the user may be to have the radiopaque marker proximate to or distant from a target catheter.

[0569] Figure 42C is a schematic expanded top view of the distal portion 4204 of the launching device 4200 of Figure 42A. Figure 42D is a schematic side view of the distal portion 4204 of the launching device 4200 of Figure 42A. In Figures 42C and 42D, the needle 4216 has been extended out of the needle aperture 4208, for example after alignment of the launching device 4200. In some embodiments, the needle 4216 can be extended by 2026223262   27 Aug 2026 operation of the actuator 4212 relative to the handle 4211. Other mechanisms are also possible (e.g., a switch, a slider, a wheel, etc.). A proximal portion 4202 having no mechanism or handle 4211 is possible (e.g., a proximal end of the needle 4216 and a proximal end of the catheter 4206 movable relative to one another by a user holding each proximal end). The needle aperture 4208 is shown proximal to the radiopaque marker 4210, but other options are also possible. For example, the needle aperture 4208 may be distal to the radiopaque marker 4210. For another example, the needle aperture 4208 may be longitudinally aligned with (e.g., radially outward of) the radiopaque marker 4210.

[0570] In some examples, the needle 4216 may be longitudinally aligned with the radiopaque marker 4210, extending in a plane perpendicular to the thin axis of the radiopaque marker 4210. Limitation of lateral movement of the needle 4216 can reduce positioning error that might otherwise result even if the alignment of the radiopaque marker 4210 is correct. For example, even if the radiopaque marker 4210 is perfectly aligned, a needle 4216 that does not extend predictably relative to the radiopaque marker 4210 can render the alignment meaningless.

[0571] Figures 42Ci-42Ciii illustrate an example catheter including a profile 4260 attached to the needle 4216. The profile 4260 slides in a shaped lumen, which can act as a slot and key system to reduce or minimize lateral and / or rotational movement of the needle 4216. The profile 4260 and corresponding lumen can have an asymmetric shape in at least one radial axis. For example, the C-shape of the profile 4260 interacts with a C-shaped surface of the lumen to inhibit or prevent the needle 4216 attached to the profile 4260 from moving laterally. In some examples, the C-shaped surface of the lumen can comprise the outer surface of a guidewire lumen (e.g., for the guidewire 4217 over which the catheter 4200 is tracked). Although illustrated in the context of the catheter 4200 including the radiopaque marker 4210, a profile 4260 can be used to laterally stabilize the needle of other catheters described herein (e.g., catheters comprising an ultrasound transducer). Symmetric shapes are also possible. Some implementations can include a sliding lap joint. Some implementations can include an interlocking tube.

[0572] When the catheter 4200 is positioned at a viewing angle parallel to a major axis of the radiopaque marker 4210, for example as shown in Figure 42D, the smallest area of the marker 4210 is visible, which can indicate alignment with a target catheter, for 2026223262   27 Aug 2026 example. Every shift in angle results in increased visible area, and a goal of the user is to reduce or minimize visible area. Radiopaque markers that are not flat (e.g., that follow the curvature of the catheter or stent) cannot achieve a thin state because the thickness is limited by the curvature and the circumferential extension of that marker. If the radiopaque marker is not flat, it may still be used consistent with some of the methods described herein (e.g., by reducing or minimizing or conversely increasing or maximizing an amount of visible marker). Upon detection of alignment, the needle 4216 can extend out of the needle aperture 4208, out of a first vessel (e.g., an artery) in which the catheter 4200 resides, through interstitial tissue, and into a second vessel (e.g., a vein), for example in which a target catheter resides. Processes as described herein may then be performed (e.g., tracking a guidewire through the needle 4216 and using the guidewire for dilation, stent delivery, a valvulotome, etc. Use of a radiopaque marker 4210, 4250 can reduce or eliminate use of more complicated and / or expensive alignment systems such as ultrasound, electric field, and magnets, but still provide assurance to the user that the needle 4216 will extend into the neighboring vessel.

[0573] In comparison to systems in which two radiopaque components need to be aligned (e.g., radiopaque components on opposite sides of a catheter, one radiopaque component on a side of a catheter and a radiopaque component in a middle of a catheter, one radiopaque component on an extendable member and a radiopaque component elsewhere on a catheter), the radiopaque marker 4210, 4250 can provide less doubt about the alignment. For example, a user may wonder whether one of the radiopaque components is not visible in an imaging plane as opposed to being aligned or not, whereas the radiopaque marker 4210, 4250 will be visible when not aligned and substantially invisible or at a minimum thickness when aligned, confirmable by small rotations. The use of shapes (e.g., two radiopaque components forming one shape), bars (e.g., multiple radiopaque components overlapping or separating), etc. can be subjective, whereas the radiopaque marker 4210, 4250 provides a substantially objective measure of whether any additional rotation makes the radiopaque marker 4210, 4250 more or less visible. Certain such shape-based radiopaque component systems may also fail to provide information about the direction of the alignment because the shape can be formed at two or more positions that are, e.g., 180° apart, whereas the radiopaque marker 4210, 4250 is clearly oriented to a desired side. Even if the shapes 2026223262   27 Aug 2026 separate or become misaligned after rotation, the separation of the shapes is non-intuitive as to direction. Certain such shape-based systems simply confirm that rotation has occurred without regard to alignment. A radiopaque dot on a side of a catheter, lacking length and width dimensions, may provide similar limited visibility in all rotational orientations, whereas the radiopaque marker 4210, 4250 shows prominently when not aligned. Subjective alignment of shapes or assessment of widths (as opposed to objective assessment of minimal thickness) can cause a few' degrees of misalignment which can cause the needle to miss the second vessel when crossing from a first vessel to a second vessel. A radiopaque hoop, for example around a circumference of a catheter, can provide information about the position of the imaging system to the catheter (e.g., w'hether parallel or perpendicular to the catheter), but does not provide rotational information about the catheter, such that the change from a circular pattern to a linear pattern is not useful for rotationally aligning the catheter. The elegant nature of the radiopaque marker 4210, 4250 can reduce manufacturing costs, for example because a complex shape and position may be avoided.

[0574] Figures 43A-43N schematically illustrate an example method of using a launching device including the distal portion 4204 of the launching device 4200 of Figure 42A. In Figures 43A-43G, the radiopaque marker 4210 is shown in an enlarged view. In some embodiments, the method may begin after performing the method of Figures 39A-39E (e.g., expanding an expandable structure or snare 1504 of a target catheter), and certain features may be shared between the methods.

[0575] In Figure 43A, the distal portion 4204 has been longitudinally advanced in a first vessel to a position longitudinally proximate to a snare 1504. The snare 1504 in this example is radiopaque and can be used as a target catheter. Other target catheters are also possible, for example having radiopaque markers on a catheter (e.g., a first radiopaque marker longitudinally spaced from a second radiopaque marker, the markers comprising marker bands in some embodiments), including a balloon filled with radiopaque material, etc. A user can see the radiopaque marker 4210 and a radiopaque feature of a target catheter under fluoroscopy.

[0576] In Figure 43B, the distal portion 4204 is rotated, as indicated by the arrow 4302. During rotation, the radiopaque marker 4210 becomes thinner. In Figure 43C, the distal portion 4204 is further rotated, as indicated by the arrow 4304. During rotation, the 2026223262   27 Aug 2026 radiopaque marker 4210 becomes thinner. At this point, a user may think that the thin radiopaque marker 4210 indicates alignment, but the radiopaque marker 4210 is on a side of the launching catheter that is opposite the snare 1504. For this arrangement in which the radiopaque marker 4210 is on the same side as the needle aperture 4208, the radiopaque marker 4210 should be proximate to the snare 1504. The radiopaque marker 4210 being relatively proximate or distant to the snare 1504 is viewable during rotation. In some embodiments, a guidewire having radiopaque properties can help determine the side of the radiopaque marker 4210. Because the radiopaque marker 4210 is thin but on the wrong side in Figure 43 C, the user continues alignment.

[0577] In Figure 43D, the distal portion 4204 is further rotated, as indicated by the arrow 4306. During rotation, the radiopaque marker 4210 becomes thicker. In Figure 43E, the distal portion 4204 is further rotated, as indicated by the arrow 4308. During rotation, the radiopaque marker 4210 becomes thinner. In Figure 43F, the distal portion 4204 is further rotated, as indicated by the arrow 4310. During rotation, the radiopaque marker 4210 becomes thinner. The radiopaque marker 4210 is now' proximate to the snare 1504 and thin, indicating alignment. In some embodiments, the alignment may stop at this point.

[0578] In Figure 43 G, the distal portion 4204 continues to be rotated or is overrotated in the direction indicated by the arrow 4312. During rotation, the radiopaque marker 4210 becomes thicker, indicating that the further rotation is making alignment worse. In Figure 43H, the distal portion 4204 is rotated in the opposite direction, as indicated by the arrow 4314. During rotation, the radiopaque marker 4210 becomes thinner. The radiopaque marker 4210 is now again proximate to the snare 1504 and thin, indicating alignment. The further rotations of Figures 43G and 43H can help to ensure a user that the alignment is correct (e.g., optimized). Rotation of the distal portion 4204 and viewing of the radiopaque marker 4210 can be similar to focusing a camera, where a user can do a coarse adjustment and a fine adjustment. For example, the coarse adjustment can be to determine whether or not the radiopaque marker 4210 is on the side proximate to the snare 1504, and the fine adjustment can be to reduce the area of the radiopaque marker 4210. The alignment may also be described as a pendulum where the user rotates the distal portion 4204 back and forth to find a low or minimum thickness of the radiopaque marker 4210. Thus may include overrotation, over-swing, over-shoot, etc. to confirm alignment. 2026223262   27 Aug 2026

[0579] Figure 43Hi schematically shows alignment of a radiopaque marker through a rotational alignment process. A catheter comprising the radiopaque marker is in a first vessel proximate or adjacent to a target vessel. The catheter is tracked over a guidewire 4217 comprising radiopaque material. When the radiopaque marker overlaps the guidewire 4217, either the front or back (or first side and opposite second side) of the radiopaque marker is visible. In this example, the radiopaque marker is on a same side of the catheter as the needle aperture. When the guidewire 4217 is between the radiopaque marker and the target, the catheter is rotationally misaligned by about 90° to about 270°. For example, even if the radiopaque marker is thin, as shown by the right-most illustration in Figure 43Hi, the catheter would be 180° misaligned. When the radiopaque marker is between the guidewire 4217 and the target, the catheter is rotationally on the correct side of the catheter. When on the correct side of the catheter and thin, as shown by the left-most illustration in Figure 43Hi, the catheter is aligned. If the radiopaque marker is thin enough, the radiopaque marker may be a thin line or even disappear from the fluoroscopy. If the radiopaque marker is on an opposite side of the catheter as the needle aperture, the process would be the opposite with respect to the guidewire 4217. The process is also possible without a guidewire 4217 or if the guidewire 4217 is not radiopaque, as the user can visualize the radiopaque marker being near or far from the target during rotation. Visualization through a range of rotational positions including the radiopaque marker being thin on both sides can inhibit, minimize, or prevent 180° misalignment.

[0580] Once the launching catheter is aligned, the needle 4216 can be extended, as shown in Figure 431. Extending the needle may include exiting a first vessel in which the distal portion 4204 resides, traversing interstitial tissue, and entering a second vessel in which the snare 1504 resides. In embodiments, the needle 4216 crosses into the snare 1504. In Figure 43J, a guidewire 4218 is extended through the needle 4216. The guidewire 4218 thereby extends through the first vessel, through the interstitial tissue, and into the second vessel.

[0581] In Figure 43K, the snare 1504 is moved distally, as indicated by the arrow 4316. The guidewire 4218 also moves distally, indicating that the guidewire 4218 is captured or entangled by the snare 1504. If the snare 1504 is moved distally before retraction of the needle 4216, distal movement of the needle 4216 can confirm engagement with the snare 2026223262   27 Aug 2026 1504 and / or being in the interior of the target vessel. Verification using the needle 4216 can be before or after advancing the guidewire 4218. In some examples, the needle 4216 can be verified, then the guidewire 4218 can be advanced, and the guidewire 4218 can be verified. In Figure 43L, the sheath 1502 is distally advanced, as indicated by the arrow 4318, capturing the snare 1504 and the guidewire 4218 entangled with the snare 1504. In Figure 43M, the sheath 1502 is further distally advanced, as indicated by the arrow 4320, further capturing the snare 1504. In some embodiments, the snare 1504 may not be fully retrievable into the sheath 1502, for example due to the entanglement with the guidewire 4218. The snare 1504 may nevertheless be radially compressed enough to move through the second vessel.

[0582] In Figure 43N, the snare 1504 is proximally retracted, as indicated by the arrow 4322. Because the guidewire 4218 is entangled with the snare 1504, the guidewire 4218 is also proximally retracted in the second vessel, or, relative to the first vessel, distally advanced. As described herein, for example, a snare technique can help to navigate the guidewire 4218 through the second vessel, for example past valves and other difficult vasculature. Catheters comprising a valvulotome, a stent-graft, and the like may be tracked over the guidewire 4218 and through the second vessel, for example as described herein.

[0583] Software may be implemented to aid in detection of the radiopaque marker 4210. The software may, for example, establish a “crossing plane” between first and second catheters and / or vessels (e.g., between a first catheter and a second catheter, between a first vessel and a second vessel, between a first catheter in a first vessel and a second vessel). To be “in the crossing plane” generally means, without limitation, that when the user advances a needle from the first vessel to the second vessel, the needle will enter the second vessel. This crossing preferably allows procedures to be performed such that fluid flows between the vessels. The crossing plane may be obtained via fluoroscopy or other imaging systems, for example by rotating the imaging head (e.g., “C-arm”) until the two vessels of interest (or a catheter in one or both of the vessels) are substantially at a maximum distance from each other. When the first vessel and second vessel are parallel, and at their maximum distance, one can say that they are in the “crossing plane” now displayed. This can be a challenging task, as measurement between vessels / catheters is typically rudimentary or done 2026223262   27 Aug 2026 “by eye.” A software solution can make the process more exact and with fewer user-driven errors (e.g., providing better precision, more reliability), and possibly more quickly.

[0584] The software may run in parallel with other software (e.g., imaging software). Figures 430i-430vi illustrate an example implementation of alignment using software. In Figure 430i, a first catheter 4200 is advanced in a first vessel 4330 and a second catheter 1500 is advanced in a second vessel 4332 proximate to an intended crossing point (e.g., proximate to and / or upstream of an occlusion in the first vessel 4330). The first vessel 4330 may be an artery. The second vessel 4332 may be a vein. The “C-arm” or other holder of an imaging system may be positioned such that it does not immediately provide an appropriate view of the vessels 4330, 4332 and / or catheters 4200, 1500. In Figure 430ii, the software measures a distance 4338 between a centerline 4334 of the first catheter 4200 and a centerline 4336 of the second catheter 1500. As the C-arm is rotated, the distance 4338 changes because the imaging plane changes. The system may control the C-arm and / or may be responsive to a user moving the C-arm. When the distance 4338 is at a maximum and / or is greater than a certain amount, the software identifies a crossing plane. The detection may be magnification dependent. When the crossing plane has been identified, the system can send a signal to a user (e.g., audible such as a beep, visual such as changing the color, dashing, thickness, etc. of the centerlines 4334, 4336, tactile such as vibration of a handle, sending a signal to a remote computing device, combinations thereof, and the like). The system may be fully or partially automated (e.g., moving on to the next step without user interaction or only upon user interaction). Combinations of line drawing and / or measurement methods / software may be used. In Figure 430iii, the image of the crossing plane optionally may be oriented as desired (e.g., such that the vessels 4330, 4332 are parallel to the lateral edges of the viewing area). In some implementations, the vessels 4330, 4332 may be filled with contrast in the viewing area, and a distance between their centerlines or an area between the contrast-filled vessels 4330, 4332 could be maximized and / or greater than a certain value to identify the crossing plane. Such techniques may be particularly suitable for non-parallel vessels 4330, 4332. Depending on the imaging system, contrast may be omitted, for example if the vessels 4330, 4332 can be identified without contrast. Combinations of catheter identification and / or vessel identification may be used. 2026223262   27 Aug 2026

[0585] The first catheter 4200 may be rotated as indicated by the arrow 4340 until the radiopaque marker 4210 has a minimum thickness or a thickness lower than a certain value. The software may use edge detection or other methods to identify the thickness of the radiopaque marker 4210 during rotation. Figure 430v shows edge lines 4342, 4344 used to measure a thickness of the radiopaque marker 4210 as a distance between the edge lines. The software may use the same or similar routines to identify edges of the radiopaque marker 4210 as to identify the centerlines 4334, 4336 in Figure 430ii. The software may use the same or similar routines to measure the distance between the edge lines 4342, 4344 as the distance 4338 between the centerlines 4334, 4336 in Figure 430ii. In some implementations, a pixel count may be used. As described above, the software also accounts for the position of the second vessel and thus can establish whether the thin radiopaque marker is facing the second vessel (or vice versa). Once the software has established that the thickness of the radiopaque marker 4210 indicates that the first catheter 4200 is properly aligned, and that the first catheter 4200 is facing the second vessel 4332, a needle 4216 can extend from the first catheter 4200, out of the first vessel 4330, and into the second vessel 4332. When rotational alignment has been identified (e.g., that the catheter is facing the correct direction and that the crossing needle will be “in the crossing plane”), the system can send a signal to a user (e.g., audible such as a beep, visual such as changing the color, dashing, thickness, etc. of the edge lines 4342, 4344, tactile such as vibration of a handle, sending a signal to a remote computing device, combinations thereof, and the like). The needle extension can be initiated by a user after receiving the signal. The needle extension can be automatic upon indicating alignment. The system may be fully or partially automated (e.g., moving on to the next step without user interaction or only upon user interaction). The second catheter 1500 may be moved longitudinally to move the needle 4216 to confirm that the needle has punctured the expandable member of the second catheter 1500, for example as described herein.

[0586] Navigation of a guidewire for retrograde venous access (e.g., against the direction of normal blood flow) can be difficult or even impossible, for example due to venous valves intended to prevent venous reflux and the many tributaries and parallel venous structures. Retrograde guidewire navigation of veins can result in diversion into branches, obstruction as a result of valves, either or both of which can cause spasm and / or perforation. Advancing a guidewire distally past a tibial venous sheath insertion point, for example, can 2026223262   27 Aug 2026 be time-consuming, sometimes taking several hours without a pedal / tibial venogram to provide a road map and / or because the peripheral vasculature, particularly distal to the heart, varies between people. Keeping the access sheath and guidewire in the tibial vein can help tension or tent the vein to allow the exchange catheter and retrograde guidewire to pass distal to the tibial access sheath. Failure to stay in the vein, which can lead to perforations, can cause vein spasms such that a procedure may need to be aborted because the user is unable to access the foot.

[0587] Advancing a guidewire around a pedal arch without a venogram or road map can lead to perforate veins and / or induce venous spasm. Perforating a vein can cause a compartment around the vein which essentially flattens the vein, hindering navigation or making navigation impossible. After a perforation, it is possible to wait 15-20 minutes to see if the perforation has resolved, try selecting an alternative venous pathway, or aborting the procedure. The user may elect to try again in a few days, for example when the perforation should be resolved. When advancing a guidewire into the foot, a user can flex the foot, use a reverse Trendelenburg posture (head elevated above feet), and / or apply a tourniquet above the ankle to increase venous pressure, thereby expanding the diameter of the vein and making navigation through valves in the vein easier, but these may not fully address perforation risk.

[0588] Antegrade pedal access offers both the opportunity for pedal venous imaging and the passage of a guidewire in a chosen vessel without the complications of valvular obstruction and diversion into branch vessels. A technique to perform consistent antegrade pedal venous access can include, for example, the use of ultrasound, techniques for venous dilatation, and / or fluoroscopic imaging.

[0589] When retrograde access to the pedal venous vasculature is desired, an initial antegrade access from the target pedal venous structure can allow the passage of a guidewire without venous valve obstruction, for example because, the guidewire is following the natural course of venous flow. An appropriately-shaped guidewire designed to align to the centerline that is introduced in this fashion has less chance of diversion into the multiple side branches, perforators, and parallel venous structures. Once a guidewire is introduced from the pedal target vein in this antegrade fashion, other catheters and devices can be introduced in a retrograde fashion with limited or without obstruction from valves that are effaced by the guidewire and / or risk of diversion into branch vessels. 2026223262   27 Aug 2026

[0590] Accessing a posterior tibial vein above the ankle and up to a crossing point, then with a crossing guidewire working in a retrograde fashion navigating past the tibial sheath and trying to get to the venous arch in the foot can be difficult, or given certain anatomy, may not even be possible. Understanding the foot anatomy can help a user access desired veins in the foot, for example because a user pass a guidewire into the connecting tibial vein and up to the crossing point, eliminating any confusion on the potential pathway.

[0591] Figure 44A. illustrates vascular anatomy of an example foot 4400. The foot 4400 includes a medial marginal vein 4402. The medial marginal vein 4402 continues towards the heart as the great saphenous vein 4401. Figures 44E and 44F also show the great saphenous vein 4401. The foot 4400 includes perforating or branch veins feeding the medial marginal vein 4402, including a submalleoral vein 4403, a scaphoid vein 4404, a cuneal vein 4405, and perforating or branch veins feeding these veins. The foot 4400 includes a first intermetatarsal space perforator vein 4406. The submalleoral vein 4403, scaphoid vein 4404, cuneal vein 4405, and first intermetatarsal space perforator vein 4406 are connected to the medial plantar veins 4407. The first intermetatarsal space perforator vein 4406 provides a consistent venous connection from the top or dorsal side of the foot 4400 to the bottom or plantar side of the foot 4400. The lateral functional unit of the foot 4400 includes lateral plantar veins 4408 and a calcaneal perforator vein 4409. In the rear of the foot 4400, the lateral plantar veins 4408 and the calcaneal perforator vein 4409 form two confluences that originate plexiform posterior tibial veins 4010.

[0592] Figure 44B further illustrates vascular anatomy of the example foot 4400. As also shown in Figure 44A, the foot 4400 includes a medial plantar vein 4407 and a lateral plantar vein 4408. The bottom of the foot 4400 includes a perforator of the first metatarsal interspace 4406. The foot 4400 includes toe veins including the first digital vein 4414 and the fourth digital vein 4416. The foot 4400 includes a cuboidal perforator 4418. The foot 4400 includes a malleolar perforator 4420. The foot 4400 includes a navicular perforator 4422.

[0593] Figure 44C shows a first dorsal metatarsal artery 4424, and extender 4426, a digital artery to great and second toes 4428, a deep peroneal nerve 4430, and a dorsal vein 4432. Figure 44D shows plantar metatarsal veins 4434, medial plantar vein 4407, posterior tibial vein 4438, lateral plantar vein 4408, and deep plantar venous arch 4442. Figure 44D also shows the first metatarsal perforator 4406, which connects plantar to dorsal veins. Figure 2026223262   27 Aug 2026 44E shows the posterior tibial vein 4438, the lateral plantar vein 4408, the medial plantar vein 4407, and the medial marginal vein 4402.

[0594] Figure 44G shows the great saphenous vein 4401, the medial marginal vein 4402, and the deep peroneal nerve 4430. In addition, Figure 44G shows the superficial peroneal nerve 4440, the saphenous nerve 4442, the small saphenous vein 4444, medial perforating veins 4446, lateral perforating veins 4448, the sural nerve 4450, the lateral marginal vein 4452, and the dorsal venous arch 4454.

[0595] Figure 44H shows the medial plantar vein 4407, the lateral plantar vein 4408, and the small saphenous vein 4444. In addition, Figure 44H shows perforators of the femoral canal 4456, an anastomosis to the deep femoral vein 4458, the femoral vein 4460, the popliteal vein 4462, the medial and lateral gastrocnemius veins 4464, a soleal vein 4466, the anterior tibial vein 4468, paratibial perforators 4470, soleal veins 4472, a soleal vein 4474, peroneal veins 4476, posterior tibial veins 4478, lateral leg perforators 4480, the upper posterior tibial perforator 4482, the middle posterior tibial perforator 4484, the lower posterior tibial perforator 4486, and the medial ankle perforator 4488.

[0596] Figure 441 is an inferior view of an anatomical dissection of lower foot veins. Figure 441 shows medial plantar veins 4407, lateral plantar veins 4408 (double), and the navicular perforator 4422. In addition, Figure 441 shows the calcaneal crossroad 4488 of the plantar veins, a plexus-shaped network 4490 of the sole, the perforator 4492 of the intermetatarsal space, and a perforator 4494 of the fifth metatarsal bone.

[0597] Figure 44J is a medial view of an anatomical dissection of lower foot veins. Figure 44J shows medial marginal vein 4402, the great saphenous vein 4401, the anterior tibial vein 4468, and the perforator vein 4492 of the first intermetatarsal space. In addition, Figure 44J shows a dorsal perforator vein 4496 that is communicating with the anterior tibial vein 4468, the submalleolar foot perforator vein 4498, the navicular perforator vein 4423, the dorsal arcade 4495 of the foot, a dorsal perforator vein 4497, and the dorsal vein 4499 the of Hallux.

[0598] Certain techniques of deep vein arterialization of the foot can target arterial inflow' at the level of the pedal veins and retrograde flow'’ into the venous pedal arch, which is the continuation of the lateral or medial plantar vein(s) through the first intermetatarsal space perforator and into the anterior tibial venous vein(s). 2026223262   27 Aug 2026

[0599] Figure 45 shows example components of a kit 4500 that may be used for pedal access. The kit 4500 includes a tourniquet 4502, an ultrasound probe 4504, and a puncture set 4506. The tourniquet 4502 may comprise a pneumatic tourniquet 4502a. The tourniquet 4502 may comprise an Esmarch tourniquet 4502b. The kit 4500 may comprise a series of tourniquets 4502 having various sizes (e.g., as shown in Figure 45) and / or various types of tourniquets 4502 (e.g., as shown in Figure 45). The ultrasound probe 4504 may comprise ultrasound appropriate for high definition venous imaging of target pedal vessels. The kit 4500 may comprise a liquid or gel configured for use with the ultrasound probe 4504. The puncture set 4506 may comprise an echogenic needle 4508 and a guideware 4510. The needle 4508 would be compatible with the diameter of the guidewire 4510, and may be selected based the depth and anatomic limitations of pedal venous structures. The needle 4508 may be fitted with a Tuohy-Borst adaptor to prevent backflow of blood. The guidewire 4510 may be, for example, 0.018 inches. The puncture set 4506 may comprise a dilator (e.g., a 2.9 Fr inner dilator fitted within a side arm for injection). The kit 4500 may comprise multiples of the described components, additional components, and / or may lack one or more of the described components. Some or all of the components of the kit may be sterile. For example, the ultrasound probe 4504 can be covered with a sterile bag, whereas the puncture set 4506 used must be sterile.

[0600] An example procedure, for example using the kit 4500, comprises using an ultrasound probe 4504 on the surface of the foot to guide a puncturer with a needle 4508. A guidewire 4510 is then inserted through the needle 4508. In some embodiments, a dilator 4512, optionally including a side arm for injections, may be optionally tracked over the guidewire 4510. The guidewire 4510 is then removed. Contrast is injected into the dilator 4512 (e.g., through the optional side arm). The volume of contrast may be, for example, about 5 mL to about 50 mL (e.g., about 5 mL, about 10 mL, about 15 mL, about 20 mL, about 25 mL, about 30 mL, about 35 mL, about 40 mL, about 45 mL, about 50 mL, ranges between such values, etc.). The contrast may be a solution, for example about 50% contrast and about 50% saline. The contrast extends to the veins in the top of the foot, the bottom of the foot, and up towards the ankle, providing a roadmap of the venous vasculature in the foot. The same or a different guidewire 4510 may then be inserted into the dilator 4512 and navigated into the venous anatomy of the user’s choice based on all of the known veins. 2026223262   27 Aug 2026

[0601] In some examples, the subject can be set in a reverse Trendelenburg position, with the head being elevated above the feet, for example between about 30 degrees and to about 45 degrees. Fluoroscopy (e.g., Digital Subtraction Imaging (DSI) selecting a large (e.g., maximum) frame size that includes all images / pathways of the veins in the foot, for example, can be used to visualize aspects of the procedure.

[0602] A first tourniquet can be positioned above the knee and a second tourniquet can be positioned above the ankle on the leg of interest. The first tourniquet can at least partially contribute to expanding the veins below the knee. The second tourniquet may at least partially contribute to expanding the veins below' the ankle. The first tourniquet can be the same type and / or size as the second tourniquet (e.g., both being pneumatic tourniquets; both being Esmarch tourniquets; etc.). The first tourniquet can be different than the second tourniquet in size and / or type (e.g., one being a pneumatic tourniquet and the other being an Esmarch tourniquet; both being pneumatic tourniquets having different sizes; etc.). The second tourniquet can block contrast from entering superficial veins, forcing the contrast into the deep veins.

[0603] In some embodiments, a metatarsal vein 4434, dorsal or plantar, can be used for injection of contrast. Palpating or tapping the vein of interest with fingers can improve success rate of the vein dilating. When the metatarsal vein 4434 is successfully cannulated, the second tourniquet around that ankle should be tight and / or should remain tight. The subject may be flattened on the table (e.g,, if originally in a reverse Trendelenburg position). Contrast may be injected into the venous vasculature from the metatarsal vein 4610 (e.g., for an ascending venogram procedure). Contrast may be injected into the venous vasculature from the great saphenous vein towards the foot (e.g., for a descending venogram procedure). One or both of the tourniquets can block contrast from entering the superficial veins, forcing the contrast into the deep veins. Anteroposterior (AP) and lateral views can be taken under fluoroscopy.

[0604] Non-ionic contrast can be used. The contrast may be warmed for ease of use, but is preferably not warmed greater than body temperature. The contrast may comprise a 50 / 50 mixture or dilution. For example, the contrast may comprise, about 15 mL of contrast diluted with 15 mL of saline. The contrast may comprise a total volume injection between about 5 mL and about 50 mL (e.g., about 5 mL, about 10 mL, about 15 mL,. about 20 mL, 2026223262   27 Aug 2026 about 25 mL, about 30 mL, about 35 mL, about 40 mL, about 45 mL, about 50 mL, ranges between such values, etc.). All or substantially all of the veins of the foot that may be potentially used for pedal access may be mapped by this quantity of contrast. More or less contrast can be used based on the subject (e.g., more for larger subjects, less for smaller subjects and / or subjects with partial feet). The second tourniquet around the ankle may be removed after mapping the veins of the foot, keeping the first tourniquet above the knee on and in place.

[0605] The injection site may be continuously monitored for possible extravasation of the contrast into soft tissue of the subject’s foot. If contrast extravasation is detected, the user may apply slight pressure to the access site to slow down / stop the extravasation, and continue to monitor.

[0606] If an occlusion is in an anterior tibial artery, pedal access may target the anterior tibial vein. A tourniquet is first placed above the ankle (e.g., to expand the veins). Guided by ultrasound, ascending venous access (towards the leg) may be obtained with a needle in the dorsal first metatarsal vein 4610 (aligned with the medial vein). A 21 gauge needle, for example, can accommodate a 0.018” guidewire. An atraumatic guidewire (e.g., having a J-shaped tip) can be advanced into the first metatarsal vein 4610. Once the guidewire is in the first metatarsal vein 4610, the needle can be removed, leaving the cannula or inserting an inner dilator. The first metatarsal vein 4610 may then be flushed through a side arm with heparinized saline. If the cannula is not properly positioned in the first metatarsal vein, the skin will blister with saline. Another method for checking positioning is to inject a small amount of a contrast medium (e.g,, if the contrast flows through the vein, if the contrast pools around the vein). Another method for checking positioning is to aspirate to see if blood comes out. Preferably, at least one check is performed to make sure the cannula is properly positioned in the vein prior to injection of a large amount of contrast medium, A dorsal and plantar venogram can be performed with an injection of contrast medium (e.g., about 5 mL to about 50 mL). A target tibial vein is selected using the venogram, and the guidewire is advanced to the target tibial vein. The tourniquet can be removed once the guidewire is in the target tibial vein. The guidewire can then be used to track devices (e.g., a target catheter for forming a fistula) through the target tibial vein. 2026223262   27 Aug 2026

[0607] If an occlusion is in a posterior tibial artery, which is more common than an anterior tibial artery, pedal access may target a lateral plantar vein. A tourniquet is first placed above the ankle (e.g., to expand the veins). Guided by ultrasound, ascending venous access (towards the leg) may be obtained with a needle in the dorsal medial marginal vein 4402 (towards the toes). A 21 gauge needle, for example, can accommodate a 0.018” guidewire. An atraumatic first guidewire (e.g., having a J-shaped tip) can be advanced into the first metatarsal vein. Once the first guidewire is in the first metatarsal vein, the needle can be removed, leaving the cannula or inserting an inner dilator. The dorsal medial marginal vein 4402 may then be flushed through a side arm with heparinized saline. If the cannula is not properly positioned in the dorsal medial marginal vein 4402, the skin will blister with saline. Another method for checking positioning is to inject a small amount of a contrast medium and see what happens (e.g., if the contrast flows through the vein, if the contrast pools around the vein). Another method for checking positioning is to aspirate fluid to see if blood comes out. Preferably, at least one check is performed to make sure the cannula is properly positioned in the vein prior to injection of a large amount of contrast medium. A dorsal and plantar venogram can be performed with an injection of contrast medium (e.g., about 5 mL to about 50 mL).

[0608] Since the occlusion is in a posterior tibular artery, methods described herein can divert oxygenated blood from the posterior tibial artery into the posterior tibial vein. The larger of the two lateral plantar veins is selected using the venogram, and the first guidewire is advanced to a crossing point or at least above the ankle. Again using ultrasound guidance on the skin, the plantar veins may be surveyed from the bottom of the foot to view the position of the first guidewire,

[0609] The second access should be made as distal as possible in the plantar arch with a needle in the lateral plantar vein with the first guidewire therein. A 21 gauge needle, for example, can accommodate a 0.018” guidewire. An atraumatic second guidewire (e.g., having a J-shaped tip) can be advanced into the lateral plantar vein and then into the posterior tibial vein and up to the crossing point. Once the second access has been made, the first guidewire could be removed. In some examples, once the second access point has been selected, the first guidewire could be removed. The ankle tourniquet can be removed once the second guidewire is in the target posterior tibial vein. The second guidewire can then be used 2026223262   27 Aug 2026 to track devices (e.g., a target catheter for forming a fistula) through the target posterior tibial vein. If a user tried to advance the first guide wire to the posterior tibial vein from the top of the foot, the first guidewire would be at a weak position and could tear tissue. The second guidewire is on the bottom of the foot where the veins are larger, and provides more robust HCC6SS.

[0610] Example procedures for performing an ascending venogram, dorsal or plantar, procedure, are described in Figures 46A-46H with reference to the anatomy described in Figures 44A-44F and the kit 4500 of Figure 45.

[0611] In Figure 46A, a tourniquet 4602 is placed above the ankle to increase venous pressure in the foot. In Figure 46B, the great saphenous vein 4401 is located. In some examples, the medial malleolus 4604, which is a prominence on the inner side of the ankle formed by the lower end of the tibia, can be used to help locate the great saphenous vein 4401. In Figure 46C, the great saphenous vein 4401 is traced toward the toes. The great saphenous vein 4401 leads to the medial marginal vein 4402. The intersection between the great saphenous vein 4401 and the medial marginal vein 4402 is the location of the first access site 4606, marked by a red X in Figure 46D. Tapping the medial marginal vein 4402, for example with a user’s fingers, can increase vasodilation, as schematically illustrated in Figure 46E. Figure 46E still shows the first access site 4606.

[0612] In Figure 46F, a first needle 4608 is used at the access site 4606 to access the medial marginal vein 4402 towards the toes. In some examples, the first needle 4608 may comprise a 21 gauge needle. A. quantity of contrast fluid is injected through the first needle 4608. In some examples, the contrast comprises contrast fluid diluted with saline. In some examples, the quantity comprises between about 5 mL and about 50 mL (e.g,, about 5 mL, about 10 mL, about 15 mL, about 20 mL, about 25 mL, about 30 mL, about 35 mL, about 40 mL, about 45 mL, about 50 mL, ranges between such values, etc.). The contrast provides a roadmap venogram for identifying a second assess site.

[0613] In Figure 46G, the first metatarsal perforator 4406 connects plantar veins on the bottom of the foot to dorsal veins on the top of the foot. In Figure 46H, a second needle 4609 is used at a second access site 4610 proximate to the first metatarsal perforator 4406 to access a lateral plantar vein 4408 towards the fifth toe. In some examples, the second needle 4609 may comprise a 21 gauge needle. In Figure 461, a guidewire 4612 is used to 2026223262   27 Aug 2026 access the lateral plantar vein 4408, for example with the tip of the guidewire 4612 prolapsed. In some examples, the guidewire 4612 may comprise an 18 gauge guidewire. An 18 gauge guidewire 4612 can fit through the lumen of a 21 gauge needle. In Figure 46J, the guidewire 4612 is advanced through the lateral plantar vein 4408 into the posterior tibial vein 4438.

[0614] The tourniquet 4602 can be removed. In some examples, the tourniquet 4602 or a different tourniquet can be placed above the knee. Under ultrasound guidance, the tibial vein 4614 with the guidewire 4612 therein can be selected for placement of a tibial access sheath, as shown in Figure 46K. In some examples, the tibial access sheath comprises a 5 Fr sheath. The guideware 4612 can be used for a vein targeting procedure, for example as described herein. The guidewire 4612 can be used for over-the-wire procedures such as fistula formation (e.g., a target catheter, a launching catheter), prosthesis placement, valve disabling, vessel lining, etc., as described herein, and the like. The pedal access procedures described herein can advantageously provide unique access point that can provide a greater amount of access to foot vessels, which can provide more flexibility in procedures and / or more access to affect vessels.

[0615] In some examples, a method comprises inserting a reentry' catheter (e.g., Outback, available from Cordis) into a pedal vein to access a tibial vein, inserting a snaring device in an arterial vasculature, tracking the snaring device to a tibial artery adjacent to the tibial vein, advancing a needle of the reentry catheter from the tibial vein towards the snare in the tibial artery, advancing a wire through the needle, snaring the wire, and retracting the snare out of the arterial vasculature. The wire can be used, for example, to create a fistula, position a prosthesis or multiple prostheses, disable valves, etc., for example as described herein.

[0616] The present application discusses several examples in which a guidewire advanced through a fistula from a first vessel into a second vessel is captured by a snare. In some examples, a valvulotome (e.g., reverse valvulotome or two-way valvulotome) is advanced over the guidewire after the guidewire has been pulled through the vessel by the snare. In some examples, a valvulotome or cutting device may be integrated or otherwise incorporate with the snare in a cutting snare system. .A cutting snare system can provide advantages such as reducing an overall number of steps in a procedure, reducing a number of 2026223262   27 Aug 2026 device exchanges, reducing procedure time, improving effectiveness of a valvulotome, reducing procedure components, improving procedure cost of goods, and / or other advantages.

[0617] Figure 47.A is a perspective view of a portion of an example cutting snare system 4700. The cutting snare system 4700 comprises a snaring mesh 4702 and cutting blades 4706. The snaring mesh 4702 may be cut from a hypotube to form cells capable of or configured to receive a guidewire (e.g., having an area greater than a diameter of a guidewire to be snared) and struts capable of or configured to capture a guidewire. The cutting snare system 4700 may be tracked over a guidewire (e.g., with an outer sheath) or tracked through a lumen of a catheter (e.g., the catheter acting as the outer sheath).

[0618] The illustrated cutting snare system 4700 includes four cutting blades 4706 circumferentially spaced by about 90°. Other quantities of blades 4706 are also possible. For example, the cutting snare system 4700 may comprise one to eight cutting blades 4706 (e.g., 1 blade, 2 blades, 3 blades, 4 blades, 5 blades, 6 blades, 7 blades, 8 blades, and ranges between such values). More than 8 cutting blades 4706 are also possible. In some examples (e.g., as shown in Figure 47A), the cutting blades 4706 may be longitudinally aligned. In some examples, the cutting blades 4706 may be longitudinally offset. In some examples (e.g., as shown in Figure 47A), the cutting blades 4706 may be evenly circumferentially spaced (e.g., two blades may be circumferentially spaced by about 180°, three blades may be circumferentially spaced by about 120°, four blades may be circumferentially spaced by about 90°, five blades may be circumferentially spaced by about 72°, six blades may be circumferentially spaced by about 60°, seven blades may be circumferentially spaced by about 51°, eight blades may be circumferentially spaced by about 45°, etc.). In some examples, the cutting blades 4706 may be circumferentially unevenly distributed.

[0619] The snaring mesh 4702 has a first outer diameter and the cutting blades 4706 have a second outer diameter. In some examples, the second outer diameter is less than the first outer diameter, which can allow the snaring mesh 4702 to appose sidewalls of the second vessel without the cutting blades 4706 cutting the sidewalls of the second vessel. Where cutting of valves in the second vessel is desired, the valves extend into the second vessel and are able to be cut by the cutting blades 4706. 2026223262   27 Aug 2026

[0620] The cutting snare system 4700 has an expanded state and a compressed state. The cutting snare system 4700 may comprise shape memory (e.g., superelastic) material (e.g., mtinol, chromium cobalt, etc.). The cutting snare system 4700 may comprise stainless steel. The cutting snare system 4700 may comprise polymer. The cutting snare system 4700 may be configured to expand from the compressed state towards the expanded state in the absence of radially inward forces (e.g., from a sheath). In some implementations, the cutting snare system 4700 may be expanded upon application of a longitudinal force to one part of the cutting snare system 4700 (e.g., a proximal end or a distal end) relative to another part of the cutting snare system 4700 (e.g., a distal end or a proximal end).

[0621] The snaring mesh 4702 can capture a guidewire, for example as described with respect to other procedures herein. Capturing the guidewire may include radially compressing the snaring mesh 4702 towards the compressed state (e.g., by capturing a proximal portion of the cutting snare system 4700 in a sheath, reversing a longitudinal expansion force, etc.). The cutting snare system 4700 is then pulled proximally, as indicated by the arrow 4707. As the cutting snare system 4700 is pulled through the second vessel, the cutting blades 4706 can cut valves of the second vessel using the same movement or physical act. In some examples, the cutting snare system 4700 can be maneuvered across a valve multiple times to increase cutting.

[0622] Figures 47Bi and 47Bii are side views of another example cutting snare system 4710. The cutting snare system 4710 comprises a snare structure 4712 and a valvulotome structure 4714 in series. The snare structure 4712 may be proximal to the valvulotome structure 4714 (e.g., as illustrated in Figure 47Bi). The snare structure 4712 may be distal to the valvulotome structure 4714 (e.g., as illustrated in Figure 47Bi). The snare structure 4712 may be monolithic or integrally formed with the valvulotome structure 4714 (e.g., as illustrated in Figure 47Bi). For example, the snare structure 4712 and the valvulotome structure 4714 may be cut from a same hypotube. A monolithic snare structure 4712 and valvulotome structure 4714 can, for example, reduce manufacturing complexity, provide strength to a joint between the snare structure 4712 and valvulotome structure 4714, etc. In some implementations, the snare structure 4712 and the valvulotome structure 4714 may be separately formed an coupled together. Separately formed snare structure 4712 and valvulotome structure 4714 can, for example, provide flexibility in materials, provide 2026223262   27 Aug 2026 flexibility in manufacturing methods (e.g., different cutting or shape-setting methods, independent creation to increase throughput), etc. The cutting snare system 4710 may be tracked over a guidewire (e.g., with an outer sheath 4718) or tracked through a lumen of a catheter (e.g., the catheter acting as the outer sheath 4718). The snare structure 4712 and / or the valvulotome structure 4714 can have the same or similar features to the other snare structures and valvulotome structures described herein, for example cells 4713 configured to capture a guidewire, cutting blades 4716, etc.

[0623] In some implementations, the snare structure 4712 can be captured in an outer sheath 4718, leaving the valvulotome structure 4714 expanded, when the valvulotome structure 4714 is proximally retracted to cut valves. In some implementations, the snare structure 4712 can be at least partially out of the outer sheath 4718 when the valvulotome structure 4714 is proximally retracted to cut valves. In some implementations, the cutting snare system 4710 can be used solely as a valvulotome, for example by only expanding the valvulotome structure 4714 (e.g., as shown in Figure 47Bii).

[0624] The snaring structure 4712 has a first outer diameter and the valvulotome structure 4714 and / or the blades 4716 have a second outer diameter. In some examples, the second outer diameter is less than the first outer diameter, which can allow the snaring structure 4712 to appose sidewalls of the second vessel without the cutting blades 4716 cutting the sidewalls of the second vessel. Where cutting of valves in the second vessel is desired, the valves extend into the second vessel and are able to be cut by the cutting blades 4716.

[0625] Figures 47Ci-47Ciii are side views of another example cutting snare system 4720. Figure 47Civ is a side view of yet another example cutting snare system 4721. The cutting snare system 4720, 4721 comprises a snare structure 4722 and a valvulotome structure 4724 configured to be in senes. The valvulotome structure 4724 may telescope inward of the snare structure 4722 (e.g., as illustrated in Figure 47Ci). The snare structure 4722 may telescope inward of the valvulotome structure 4724 (e.g., as illustrated in Figure 47Civ). The cutting snare system 4720, 4721 may be tracked over a guidewire (e.g., with an outer sheath 4728) or tracked through a lumen of a catheter (e.g., the catheter acting as the outer sheath 4728). Figure 47Cii show's the snare structure 4722 and the valvulotome structure 4724 sheathed in the outer sheath 4728 for tracking over a guidewire and / or through 2026223262   27 Aug 2026 a catheter. The snare structure 4722 and / or the valvulotome structure 4724 can have the same or similar features to the other snare structures and valvulotome structures described herein, for example cells 4723 configured to capture a guidewire, cutting blades 4726, etc.

[0626] In some implementations, the snare structure 4722 can be at least partially out of the outer sheath 4728 when the valvulotome structure 4724 is proximally retracted to cut valves. In some implementations, the cutting snare system 4720, 4721 can be used solely as a valvulotome, for example by only expanding the valvulotome structure 4724 through the for the cutting snare system 4720 (e.g., as shown in Figure 47Ciii) and / or by not expanding the snare structure 4722 for the cutting snare system 4721.

[0627] In the cutting snare system 4720, the snaring structure 4722 has a first outer diameter and the valvulotome structure 4724 and / or the blades 4726 have a second outer diameter. In some examples, the second outer diameter is less than the first outer diameter, which can allow the snaring structure 4722 to appose sidewalls of the second vessel without the cutting blades 4726 cutting the sidewalls of the second vessel. Where cutting of valves in the second vessel is desired, the valves extend into the second vessel and are able to be cut by the cutting blades 4726.

[0628] In the cutting snare system 4721, the snaring structure 4722 has a first outer diameter and the valvulotome structure 4724 and / or the blades 4726 have a second outer diameter. In some examples, the second outer diameter is greater than the first outer diameter, which can allow the snaring structure 4722 to appose sidewalls of the second vessel, for example when the valvulotome structure 4728 is in the outer sheath 4728 and cannot cut the sidewalls of the second vessel. Where cutting of valves in the second vessel is desired, the valves extend into the second vessel and are able to be cut by the cutting blades 4726. The second diameter being greater than the first diameter can allow the cutting blades 4726 to cut more of the valve.

[0629] Figures 47Di-47Dv are side views of still another example cutting snare system 4730. The cutting snare system 4730 comprises a snare structure 4732 shown in Figure 47Di and a valvulotome structure 4734 shown in Figure 47Dii. The snare structure 4732 and / or the valvulotome structure 4734 can have the same or similar features to the other snare structures and valvulotome structures described herein, for example cells 4733 configured to capture a guidewire, cutting blades 4736, etc. The snare structure 4732 and / or 2026223262   27 Aug 2026 the valvulotome structure 4734 may include an atraumatic distal tip, for example a tapered nose.

[0630] The outer sheath 4738 can be left in place, for example after another procedure described herein. The cutting snare system 4730 may be tracked through a lumen or multiple lumens of a catheter 4738, which acts as an outer sheath for the cutting snare system 4730. Figure 47Div shows the snare structure 4732 extending out of the distal end of the outer sheath 4738. The snare structure 4732 can snare a guidewire, for example as described herein. In some implementations, the snare structure 4732 is sized so that the snare structure 4732 and a captured guidewire can be proximally retracted out of the proximal end of the outer sheath 4738. Figure 47Dv shows the valvulotome structure 4734 extending out of the distal end of the outer sheath 4738. The valvulotome structure 4732 can be proximally retracted in the direction 4737 to cut valves, for example as described herein.

[0631] Figures 47Ei-47Eiii are side views of still yet another example cutting snare system 4740. Figure 47Eiv is a side view of another example cutting snare system 4741. The cutting snare system 4740 comprises a snare structure 4742 and an expandable member 4744 radially inward of the snare structure 4742. The cutting snare system 4740 may be tracked over a guidewire (e.g., with an outer sheath 4748) or tracked through a lumen of a catheter (e.g., the catheter acting as the outer sheath 4748).

[0632] The snare structure 4742 can have the same or similar features to the other snare structures described herein, for example cells 4743 configured to capture a guidewire, etc. The snare structure 4742 may include an atraumatic distal tip, for example a tapered nose. The expandable structure 4744 comprises, for example, a balloon and / or a plurality of expandable wires. In some implementations, the expandable structure 4744 is coupled to the snare structure 4742 (e.g., as shown in Figures 47Ei-47Eiii). This can, for example, help to ensure alignment of the snare structure 4742 and the expandable structure 4744 when applying a cutting force, as described below. In some implementations, the expandable structure 4744 is separate from the snare structure 4742 (e.g., as shown in Figure 47Eiv). This can, for example, allow more space for a guidewire during snaring, allow' the use of various types of expandable members (e.g., selected for a particular vessel), etc.

[0633] The outer sheath 4748 can be left in place, for example after another procedure described herein. The cutting snare system 4740 may be tracked through a lumen 2026223262   27 Aug 2026 or multiple lumens of a catheter 4748, which acts as an outer sheath for the cutting snare system 4740. Figure 47Eii shows the snare structure 4742 extending out of the distal end of the outer sheath 4748. The snare structure 4742 can snare a guidewire, for example as described herein. In some implementations, the snare structure 4742 is sized so that the snare structure 4742 and a captured guidewire can be proximally retracted out of the proximal end of the outer sheath 4748. After the cutting snare system 4740 has been proximally retracted out of the proximal end of the outer sheath 4748, the cutting snare system 4740 may be reinserted into the outer sheath 4748 (e.g., as illustrated in Figure 47Eiii) and / or over a guidewire. In some implementations, a separate cutting snare system 4740 may be inserted into the outer sheath 4748 and / or over a guidewire.

[0634] Figures 47Eii and 47Eiii show the cutting snare system 4740 extending out of the distal end of the outer sheath 4748. In some implementations, the cutting snare system 4740 is across a valve (e.g., in a vein). In Figure 47Eii, the expandable structure 4744 is partially expanded (e.g., inflated) within the snare structure 4742. In Figure 47Eiii, the expandable structure 4744 is further expanded (e.g., inflated) within the snare structure 4742 until the expandable structure 4744 applies a radially outward force, as indicated by the arrows 4747, to the snare structure. The force can press the struts or mesh of the snare structure 4742 into valve leaflets, which can cut the valve leaflets and / or disable the valve.

[0635] The amount of expansion pressure may be related to the sharpness or aggressiveness of the cutting mechanism (e.g., blade, wire, etc.). The expansion pressure maybe between about 4 atm (approx. 405 kPa) and about 20 atm (approx. 2,026 kPa) (e.g., about 4 atm (approx. 405 kPa), 7 atm (approx. 709 kPa), 10 atm (approx. 1,013 kPa), 15 atm (approx. 1,520 kPa), 20 atm (approx. 2,026 kPa), ranges between such values, etc.). Pressures higher and lower than those listed may be possible depending on the cutting mechanism.

[0636] Lower pressure may be useful for sharp, aggressive cutting blades. In some examples, a lower pressure balloon with a more aggressive blade potentially has the advantage of cutting the valve while causing less trauma to the surrounding vessel tissue. In the initial contact of the blades with the valve, force is localized at the blade. The sharper the blade, the less force required. As the balloon engages the wall, the lower force is maintained, causing less distention to the vein. 2026223262   27 Aug 2026

[0637] Higher pressure may be useful for a mild cutting wire or no wire at all. In some examples, the mechanical properties of the valve tissue make the valve very resistant to traditional balloons. A higher-pressure balloon (e.g., cutting or not) can exert more force that might be needed to defeat the valve. Blades on a cutting balloon may initiate a cut, but the balloon can further propagate these cuts. Higher force may enable greater propagation of the cut, more effectively disabling the valve.

[0638] The expandable member 4744 can be deflated or reduced, and the cutting snare system 4740 can be moved, for example to extend across a second valve. The expandable structure 4744 can be again expanded (e.g., inflated) to disable the second valve. The process may be repeated for as many valves as are desired to be disabled,

[0639] Figures 47Fi and 47Fii are side views of yet another example cutting snare system 4750. The cutting snare system 4750 comprises a structure 4752 that can snare a guidewire in a first state and / or a second state and cut valves in the second state. Figure 47Fi show's the structure 4752 in the first state, in which the structure 4752 has a generally oval form. The structure 4752 can snare a guidewire, for example as described herein, in the first state.

[0640] Figure 47Fii show the structure 4752 in the second state, in w'hich the structure 4752 includes proximal cutting elements 4754. The structure 4752 in the second state can cut valves, for example as described herein. The structure 4752 in the second state can snare a guidewire, for example as described herein. In certain implementations, the structure 4752 can cut valves while the structure 4752 is proximally retracted with a snared guidewire. In some implementations, the guidewire may be snared with the structure 4752 in the first state, and the structure 4752 may be reinserted to cut the valves in the second state.

[0641] In some implementations, the structure 4752 can change from the first state to the second state by applying a longitudinal force 4755 to the structure 4752, for example proximally retracting a distal end of the structure 4752 relative to a proximal end of the structure. Other forces are also possible. For example, twisting or torqueing forces, use of temperature induced martensite, etc.

[0642] Figures 47Gi-47Giii are side views of still another example cutting snare system 4760. The snare cutting system 4760 may comprise a snare structure 4762 and a valvulotome structure 4764 in series, for example as shown in the cutting snare system 4721 2026223262   27 Aug 2026 of Figure 47Civ. The snare structure 4762 and / or the valvulotome structure 4764 can have the same or similar features to the other snare structures and valvulotome structures described herein, for example cells configured to capture a guidewire, cutting blades, etc.

[0643] In Figure 47Gi, the snare structure 4762 and valvulotome structure 4764 are collapsed inside the outer sheath 4768. In Figure 47Gi, the snare structure 4762 has been distally advanced relative to the outer sheath 4768. The snare structure 4762 can snare a guidewire, for example as described herein.

[0644] The snare cutting system 4760 comprises an outer sheath 4768 comprising a plurality of elongate apertures 4765. In Figures 47Gii, the valvulotome structure 4764 is visible through the apertures 4765. In Figure 47Giii, the valvulotome structure 4764 has been rotated relative to the outer sheath 4768 such that the struts of the valvulotome structure 4764 can laterally extend from an intermediate portion of the outer sheath 4768 proximal to the distal end of the outer sheath 4768, as shown in Figure 47Giii. The valvulotome structure 4764 can be proximally retracted in the direction 4767 to disable valves, for example as described herein.

[0645] The procedures described herein generally divert blood from a first cavity (e.g., an occluded artery) to a second cavity (e.g., the lateral plantar vein). In some circumstances, a user may desire to divert blood into a different second cavity than the lateral plantar vein. For example, the lateral plantar vein may be perforated (e.g., due to use for a previous surgical bypass procedure), may be occluded (e.g., due to thrombosis and / or stenosis), may be too far from the first cavity, etc. Blood generally flows from high pressure to low pressure along any available return path, so blood may bypass certain restricted areas, whereas the blood would preferably pass through and / or dwell in extremities. Procedures described herein can include providing retrograde blood flow through a plurality of vessels.

[0646] Occlusions and stenoses in the peripheral arterial system can inhibit or prevent oxygenated blood from reaching the distal limbs / extremities such as the hands and feet. Reduction in peripheral arterial blood flow can impede the body’s ability to heal wounds in these areas, and may ultimately result in partial or full amputation of the limb. Arterialization of the venous system, for example as described herein, can allow for oxygenated (normally arterial) blood to reach the distal limb to heal wounds and reduce the risk of amputation. Figure 48A illustrates an example image of a foot after a venous 2026223262   27 Aug 2026 arterialization procedure. Blood can be seen flowing around major vessels of the foot. Merely establishing a venous circuit with retrograde arterial blood flow may not be enough to drive wound healing.

[0647] The quality / performance of the retrograde circuit can be an important consideration, for example including its ability to achieve perfusion of oxygenated arterial blood into the most distal regions of the limb (e.g., forefoot, toes, heel), where wounds are typically present. Achieving distality of blood flow is typically needed for wound healing. If a circuit has been established that has robust flow, the flow may fail to reach the most distal vessels, for example because the blood will tend to return via the “path of least resistance.” Methods and devices that allow the establishment of “high quality” retrograde venous circuits in a controlled and planned manner can enable adequate perfusion of the distal limb to heal wounds more effectively and further reduce the risk of amputation. A limb can include an arm and a distal limb could include a hand and / or fingers.

[0648] Perfusion in retrograde venous arterialization is a complex function of, for example, blood flow rate, flow volume, pressure, anatomy, physical properties of tissue / blood (e.g., viscosity, etc.), and / or the physical geometry of the circuit (e.g., number of inflow and outflow pathways, size / caliber of the vessels, etc.). Modification of a single or multiple variables may influence one or more other variables, which in turn may increase or decrease the circuit’s ability to adequately perfuse blood to the target wound.

[0649] An example method of causing perfusion in the retrograde venous circuit is to increase pressure in the circuit by reducing the blood’s ability to simply “shunt” back to the venous return to the heart. For example, the embolization of specific “blood-stealing” outflow veins (e.g., side branches) can close off these return veins. Because retrograde blood cannot quickly find a low pressure (low resistance) return pathway, it is forced to move distally, into the small vessels responsible for feeding tissue near the limb surface, where wounds occur. For a given flow rate, reducing the number of outflow vessels will generally increase the pressure in the circuit, increasing the likelihood of distal perfusion. A similar effect can be accomplished via a covered graft, flow-diverting stent, etc. Improving distal perfusion could enhance collateralization and / or neoangiogenesis, which can further improve distal perfusion, for example in the long term. 2026223262   27 Aug 2026

[0650] Figure 48B illustrates another example image of a foot after a venous arterialization procedure. Compared to Figure 48A, blood can be seen flowing to many more vessels. Blood flow to more vessels, particularly in an extremity like the foot, can help with wound healing and reduce the risk of amputation. Certain methods described herein can achieve blood flow in all circuits in all veins, including deep and superficial veins. The retrograde flow can start at any peripheral artery, for example as high as the femoral system, continue throughout the tibial system, and continue distal in the foot. For example, the veins that can be claimed by retrograde flow' can include greater veins including their redundant veins (e.g., posterior tibial vein, anterior tibial vein, great saphenous vein, small saphenous vein), veins distal to the greater veins and their redundant veins (e.g., lateral plantar vein, lateral marginal vein, medial plantar vein, medial marginal vein, fibuiar veins, dorsal arcade of the foot, dorsal vein of the Hallux), and perforator veins and their redundant veins that connect the upper and lower vein networks of the foot (e.g., medial foot perforators (inframalleolar, navicular / scaphoid, cuneal), lateral foot perforators (intertendinous, subtendinous), and calcaneal foot perforator). In some implementations, blood can flow to some, a majority, or all of these veins.

[0651] Figure 49 illustrates an example method of providing blood flow to a plurality' of veins. In an original procedure, blood from an occluded posterior tibial artery was diverted into a medial plantar vein 4407 through a fistula prosthesis (e.g., as described herein). Blood was able to flow from the medial plantar vein 4407 to the anterior tibial vein 4468. In a second procedure several weeks after the first procedure, a loop 4800 was established from the medial plantar vein 4407 to the lateral plantar vein 4408 (e.g., bydisabling valves that would otherwise inhibit or prevent flow therebetween). The lateral plantar vein 4408 was accessed downstream of an occlusion therein. A stent was positioned downstream of the fistula in the lateral plantar vein, although the stent could be positioned in any vessel in the retrograde flow circuit for this purpose.

[0652] The stent kept the vessel open and patent. The stent kept the valves in the vessel open to permit retrograde flow, prosthesis to help maintain a flow deep in the foot, for example by propping open valves. The stent was a paclitaxel-eluting stent (ELUVIA™, available from Boston Scientific), although other drug eluting stents, bare metal stents (e.g., SUPERA®, available from Abbott Vascular), stent-grafts, polymer stents, etc. could also be 2026223262   27 Aug 2026 used. Preferably, the stent can handle the dynamic ankle bend. The stent optionally inhibits or prevents perfusion through sidewalls to or from branch vessels (e.g., by including a graft, having a low porosity such as a flow diverter, etc.). The stent may be small (e.g., 5 Fr, 4 Fr, 3 Fr, or even smaller (e.g., a 3 Fr or 4 Fr woven stent or a 4 Fr or 5 Fr laser cut stent)). The diameter of the stent could be, for example, between about 2 mm and about 6 mm (e.g., about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, ranges between such diameters, etc.).

[0653] Retrograde How in the combination of the medial plantar vein 4407 and the lateral plantar vein 4408, which included a vessel on each side of the loop 4800, led to greater perfusion of the arch and the distal foot than either a circuit with only the medial plantar vein or the lateral plantar vein could achieve alone, as blood was forced to flow distally through a collateral network. Without being bound by any particular theory, it is believed that blood was forced to return to the heart via the collateral network rather than larger veins. In some implementations, the lateral plantar vein 4408 could be accessed in the original procedure or after a shorter or longer duration than six weeks. In some implementations, a plurality of fistulas may be formed (e.g., using the procedures described herein) to cause retrograde flow in a plurality of veins. Preferably, the plurality' of veins includes one vein on each side of the dorsal venous arch 4454.

[0654] In some implementations, retrograde oxygenated blood flow has been established in one or more venous circuits via venous arterialization (e.g., as described herein). Additional methods may be used to further direct flow to specific regions of the foot to increase perfusion.

[0655] Some methods can include creating a fistula between a first vessel (e.g., an artery') and a second vessel (e.g., a vein) in the foot (e.g., as opposed to above the ankle), for example using techniques described herein. In the venous system, a plurality of vessels transmit blood back to the heart. The system includes copious redundancy, many interconnections, bifurcations, and confluences. The venous system is a “low pressure” system, as opposed to the higher pressure arterial system. When pressurizing the venous system with arterial blood flow', the blood will take the path of least resistance (e.g., to outflow vessels connected to the low-pressure return, where there are no valves to block flo w). Many of these return vessels are proximal to a desired blood path in the distal limb or 2026223262   27 Aug 2026 extremity, and therefore “steal” blood away from the intended target. By terminating one, some, or all of these vessels, flow can be directed and / or pressure can be increased to help increase distal perfusion in a controlled manner.

[0656] Some methods can include limiting and / or adjusting an outflow in the venous system (e.g., limiting vessel steal or shunting of blood). For example, a stent or stent graft can channel blood past stealing vessels. For another example, bifurcating veins or side branches can be embolized (e.g., via coils, microspheres, liquid embolics, laser, etc.). Figure 50 illustrates a method of using embolization coils 5002 to prevent vessel steal and redirect blood distally, as annotated by the arrow 5004, which indicates a direction of oxygenated blood flow.

[0657] Some methods can include physically directing the retrograde, oxygenated blood into multiple target veins instead of a single target vein (e.g., as described above with respect to Figure 49). For example, valves can be disabled (e.g., using a valvulotome, balloon, stent, etc.) in more than one vein. Distal pedal access as described herein may help with such disabling by providing access to all of the desired veins including valves to be disabled. Valvulotomes as described herein may help with such disabling by allowing ablation during distal advancement and / or during advancement or retraction. For another example, multiple venous arterializations can be performed to direct the flow of oxygenated blood from two or more arteries into two or more veins, for example one or each using methods described herein. For another example, an increase in pressure in the venous system is able to overcome resistance of the valves, which can aid in perfusion when the pressure increase occurs in veins extending to the distal extremity (e.g., foot, hand, toes, fingers).

[0658] Some methods can include applying external pressure (e.g., cuff, tourniquet, wrap) to increase blood pressure in the foot by limiting venous outflow, for example because blood has nowhere to go but distal. The pressure application can be continuous or intermittent. Combinations of these methods are possible, and other methods are possible.

[0659] Certain fistula prostheses described herein are configured to direct 100% or all of the fluid from a first vessel into a second vessel. Such a configuration may be most suitable, for example, for treatment of an artery having chronic total occlusion in which the prosthesis is positioned proximate to the occlusion, as anything downstream of the occlusion 2026223262   27 Aug 2026 was likely already occluded. In some circumstances, the artery is not totally occluded, can be at least partially opened, treatment includes placement of the prosthesis well upstream of the occlusion such that healthy branch arteries still providing some benefit might be starved of blood or “jailed,” and / or “vessel steal” reduces flow to other vessels. Placement upstream can be the result of a diseased or calcified artery being difficult to cross (e.g., due to calcification, due to compromised and / or poor inflow, etc.) and / or stent. Fluid moves from high pressure to low pressure, so when a high pressure artery is connected to a low pressure vein, blood may have a tendency to flow to the vein, which can compromise or “steal” the amount of blood that flows to other arteries (e.g., peroneal artery). Reduced blood flow in other arteries may cause ischemia and / or pain in anatomy supplied by the vessels having blood stolen therefrom.

[0660] Allowing at least some blood to continue to flow in the first vessel, or distal arterial flow preservation, may provide one or more advantages. For example, intentionally placing the prosthesis upstream of an occlusion can allow the crossing and stenting in the first vessel to be in a healthier portion of the first vessel (e.g., little to no calcification, good inflow, etc.) and / or a portion of the first vessel that may be easier to cross into the second vessel. Freedom of placement position can provide significant flexibility' to a user. For another example, blood can continue to flow to downstream branch vessels can maintain the existing arterial network, such as maintaining the benefit of those branch vessels. For yet another example, vessel steal can be inhibited or prevented because the blood can continue to flow in the arterial system. Ischemia and / or pain caused from stolen blood might be avoided. For another example, interventional procedures (e.g., plain, drug eluting, and / or scoring angioplasty, atherectomy, PTA, etc.) may be performed downstream of the prosthesis and / or in conjunction with the procedure, allowing percutaneous crossing to be further used as adjunctive therapy with more traditional treatments. Venous arterialization may be performed on a larger class of subjects. For example, while Rutherford Class 5 or 6 patients typically have a critical limb ischemia or chronic total occlusion, Rutherford Class 3 or 4 (or lower) patients may have peripheral artery disease or claudication that only partially occludes an artery. In contrast to other so-called fenestrated stent grafts, such as descending aortic stent grafts with specific cutouts for connecting additional stent grafts to form artificial branch arteries to, for example, the kidneys, or such as aortic stent grafts with specific 2026223262   27 Aug 2026 cutouts to permit perfusion to vessels carrying blood to the head or arms, the windows of the fenestrated stent grafts described herein permit perfusion to continue to the distal parent, and the blood flowing through the main lumen of the fenestrated stent graft is diverted into a second vessel different than the parent.

[0661] Figure 51A is a partial cross-section of an example device 5100 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The first vessel 5101 is at least partially occluded. The first vessel 5101 may comprise an artery (e.g., a peripheral artery such as a tibial artery) and the second vessel 5102 may comprise a vein (e.g., a peripheral vein such as a tibial vein). The device 5100 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein.

[0662] The device 5100 comprises a first section 5104 and a second section 5106. The first section 5104 generally abuts or partially overlaps the second section 5106. The device 5100 may comprise a radiopaque marker 5107 showing a transition 5105 between the first section 5104 and the second section 5106. The marker 5107 may be, for example, swaged, electroplated, a threaded wire, a band, change in strut pattern, change in cell structure, etc.

[0663] The first section 5104 comprises a stent structure 5108. The stent structure 5108 may comprise woven and / or knitted wires, cut struts, combinations thereof, etc. The first section 5104 comprises pores or apertures 5103 that allow blood to flow into the proximal end of the stent structure 5108 into the stent structure 5108, and then from inside the stent structure 5108 to outside the stent structure 5108, and downstream in the first vessel 5101, as indicated by the arrow 5112, The stent structure 5108 is configured to anchor the first section 5104 in the first vessel 5101. The first section 5104 may comprise a radiopaque marker, for example at the proximal end of the first section 5104. The device 5100 may comprise an additional section proximal to the first section 5104.

[0664] The second section 5106 comprises the stent structure 5108 and a covering or graft 5109. The stent structure 5108 may be the same or different (e.g., having at least one parameter that is different (e.g., cell structure, density, porosity, material, dimensions such as diameter, thickness, and / or length), etc.) between the first section 5104 and the second section 5106, and / or within the first section 5104 and / or the second section 5106. The second 2026223262   27 Aug 2026 section 5106 may be integral or monolithic with the first section 5104. The graft 5109 of the second section 5106 is configured to provide a fluid flow passage from the first vessel 5101 to the second vessel 5102, as indicated by the arrow 5110. Blood can flow through the second vessel 5102 as described herein. The graft 5109 preferably does not comprise pores configured to allow blood flow from inside to outside. The stent structure 5108 is configured to anchor the first section 5106 in the second vessel 5102. The second section 5106 may comprise a radiopaque marker, for example at the distal end of the second section 5106. The device 5100 may comprise an additional section distal to the second section 5106. The proximal end of the graft 5109 may be generally perpendicular to a longitudinal axis of the device 5100, which could provide ease of manufacturing and / or deployment (e.g., because rotational orientation does not matter). The proximal edge of the graft 5109 may include a pattern, for example straight, angled, scalloped, eccentric, etc.

[0665] Figure 5IB is a side view of another example device 5120 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5120 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5120 may share several of the features of the device 5100 (e.g., first section 5124, second section 5126, stent structure 5128, graft 5129, etc.). The transition 5125 of the device 5120 is not generally perpendicular, but is at an angle a, to the longitudinal axis of the device 5120. The angle a may be measured against a sidewall (e.g., as shown in Figure 5IB), which may be an easy measurement because there is solid material forming both sides of the angle a. The angle a may be measured against an artificial longitudinal axis extending through the device 5120, which may be an easy measurement when sidewalls of the device 5120 are tapered in the transition 5125. The angle a may be, for example, between about 10° and about 70° (e.g., about 10°, about 20°, about 30°, about 40°, about 50°, about 60°, about 70°, ranges between such values, etc.). Higher and lower angles a are also possible, for example for indications in which the second vessel 5102 is close to the first vessel 5101 or far from the first vessel 5101, respectively. The angled transition 5125 may provide better continued flow through the first vessel 5101, as indicated by the arrow 5112, because less of the first vessel 5101 is occluded. Deploying the device 5120 may comprise rotationally orienting the device 5120, for example in the orientation shown in Figure 5 IB. The device 5120 may 2026223262   27 Aug 2026 comprise a first radiopaque marker 5127a at the proximal-most point of the transition 5125 and a second radiopaque marker 5127b at the distal-most point of the transition 5125, for example because material for the graft 5129 may be generally radiolucent.

[0666] Figure 51C is a side view of yet another example device 5140 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5140 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow'’ preservation advantages described herein. The device 5140 may share several of the features of the device 5100 (e.g., first section 5144, second section 5146, stent structure 5148, graft 5149, etc.). The stent structure 5148 may be the same or different (e.g., having at least one parameter that is different (e.g., cell structure, density, porosity, material, dimensions such as diameter, thickness, and / or length), etc.)) between the first section 5144 and the second section 5146, and / or within the first section 5144 and / or the second section 5146. In some implementations, the second section 5146 may lack a stent structure.

[0667] The first section 5144 and the second section 5146 of the device 5140 are separate and deployed sequentially. For example, the first section 5144 may be deployed first and the second section 5146 may be deployed second, with the distal segment of the first section 5144 radially outward of the proximal segment of the second section 5146. The first section 5144 can establish structural support for the fistula. For another example, the second section 5146 may be deployed first and the first section 5144 may be deployed second, with the distal segment of the first section 5144 radially inward of the proximal segment of the second section 5146. The first section 5144 can help prop open the fistula, provide radial outward pressure on the segment of the second section 5166 that overlaps with the first section 5144, and / or reduce turbulence effects that otherwise might be caused by the proximal end of the second section 5146. At least one of the first section 5144 or the second section 5146 may comprise an anchor configured to inhibit or prevent relative movement between the first section 5144 and the second section 5146 after deployment. For example, the anchors may include radially-outward protrusions, hooks, barbs, detents, etc., which may be m the stent structure 5148 or attached to the first section 5144 and / or the second section 5146. In some implementations, the anchors may comprise a ratchet. For example, the the first section 5144 and the second section 5146 may be relatively longitudinally and / or 2026223262   27 Aug 2026 rotationally moved relative to each other, for example segment-by-segment, until locked im place. Anchors may facilitate orientation of the device 5140 (e.g., only being anchored when properly oriented). The anchor may interact with the other of the first section 5144 and / or the second section 5146 and / or may interact with the first vessel 5101, the second vessel 5102, and / or interstitial tissue. Limiting relative movement can help to maintain the graft 5149 boundary to ensure that the first vessel 5101 is not jailed. The device 5140 may provide a user with ease of deployment. For example, the first section 5144 can be comfortably deployed to support the first vessel 5101 without much accuracy. Then, the second section 5146 can be deployed using a more accurate deployment system to hit the target (e.g., the proximal end hitting an edge of the first vessel 5101) to ensure that the first vessel 5101 is not jailed.

[0668] The first section 5144 anchors in the first vessel 5101, extends through interstitial tissue, and into the second vessel 5102. The second section extends from at least partially in the first vessel 5101, through interstitial tissue, and anchors in the second vessel 5102. At least some segment of the first section 5144 does not overlap with the second section 5146. The non-overlapping segment of the first section 5144 is free from graft material, which allows blood to continue to flow in the first vessel 5101, as shown by the arrow 5112. The second section 5146 allows blood to flow into and through the second vessel 5102, as shown by the arrow 5110. The proximal end of the graft 5149 of the second section 5146 may be substantially perpendicular (e.g., as shown in Figure 51C), or may be angled (e.g., tike the graft 5129 described with respect to the device 5120). The proximal and / or distal ends of the first section 5144 and / or the second section 5146 may comprise a radiopaque marker 5147, for example to help a user determine an anchoring position, an amount of overlap, a rotational orientation, etc.

[0669] Figure 51D is a side view of still another example device 5160 providing fluid flow from a first vessel to a second vessel and through the first vessel. The device 5160 allows at least some blood to continue to flow in the first vessel, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5160 may share several of the features of the devices 5100, 5120 (e.g., first section, second section, stent structure, graft 5169, etc.). Only the graft 5169 is shown in Figure 5 ID for simplicity. The graft 5169 includes a cutout 5168 where the device 5160 does not include the 2026223262   27 Aug 2026 graft 5169 such that the stent structure is bare. The percentage of bare circumference is variable along the length of the device 5160 , for example a V-shaped cutout 5168 (e.g., as shown m Figure 51D) that reduces from a first percentage (e.g., about 50%) of bare stent structure to a second percentage (e.g., about 10%) of bare stent structure less than the first percentage as the device 5160 extends distally. A lower percentage may be advantageous for orienting the device 5160. The percentage generally relates to the flow'’ resistance through the first vessel. In anatomy where more flow is desired (e.g., proximal or upstream in the first vessel (e.g., closer to the groin)), the percentage may be higher so that more blood can flow' to the larger and / or more numerous vessels downstream. In anatomy where less flow is desired (e.g., distal or downstream in the first vessel (e.g., closer to the foot)), the percentage may be lower so that more blood can flow to the second vessel.

[0670] In general, the cutout 5169 of the device 5160 can be at least partially defined using a few variables that describe the opening in the covering: the angle 5162 from proximal to distal; the length 5164; the width 5166 at the proximal end of the cutout 5169; and / or the width 5167 at the distal end of the cutout 5169. These variables can be adjusted or tuned to correspond to any overall shape, with other features (such as scallops) possible at a more detailed level. The device 5169 can include as many cutouts as desired, at any length along the device 5160.

[0671] Figure 52A is a side view' of still another example device 5200 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5200 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5200 comprises a first section 5204 and a second section 5206. The first section 5204 at least partially longitudinally overlaps the second section 5206. In some examples, the proximal end and / or distal end of the first section 5204 is substantially longitudinally aligned with the respective proximal and / or distal end of the second section 5206. Each of the first section 5204 and the second section 5206 anchors in each of the first vessel 5101 and the second vessel 5102. The proximal and / or distal ends, and / or other parts (e.g., a longitudinal center), of the first section 5204 and / or the second section 5206 may comprise a radiopaque marker 5207. 2026223262   27 Aug 2026

[0672] The first section 5204 comprises a stent structure 5208, for example like the stent structure 5108. The first section 5204 comprises pores or apertures 5203 that allow blood to flow into the proximal end and / or through the pores 5203 of the stent structure 5208 into the stent structure 5208, and then flow from inside the stent structure 5208 to outside the stent structure 5208, and downstream in the first vessel 5101, as indicated by the arrow 5112. As described herein, only the first section 5204 may comprise the stent structure 5208 or the both the first section 5204 and the second section 5206 may comprise the stent structure 5208.

[0673] The second section 5206 comprises a covering or graft 5209 and optionally the stent structure 5208. In embodiments comprising the stent structure 5208, the stent structure 5208 may be the same or different (e.g., having at least one parameter that is different (e.g., cell structure, density, porosity, material, dimensions such as diameter, thickness, and / or length), etc.) between the first section 5204 and the second section 5206, and / or within the first section 5204 and / or the second section 5206. The graft 5209 of the second section 5206 is configured to provide a fluid flow passage from the first vessel 5101 to the second vessel 5102, as indicated by the arrow 5110. Blood can flow through the second vessel 5102 as described herein. The graft 5209 preferably does not comprise pores configured to allow blood flow from inside to outside.

[0674] The second section 5206 may be integral or monolithic with the first section 5204. The first section 5204 and the second section 5206 may be deployed at substantially the same time. The first section 5204 may be separate from the second section 5206 such that they may be deployed substantially simultaneously or at least partially separately. In some implementations, the stent structure may have a figure-8 cross section, in which the first section 5204 comprises the top half of the 8 and the second section 5206 comprises the bottom half of the 8. In some implementations, the stent structure 5208 may form a lumen and the graft 5209 may extend across the lumen, forming two flow paths: a first porous flow path through the first section 5204 and a second nonporous flow path through the second section 5206. Because both the first section 5204 and the second section 5206 extend into the second vessel 5102, positioning of the device 5200 may be simplified, for example because rotational orientation generally does not affect function, although a user may prefer that the second section 5206 be adjacent to the second vessel 5102. The inventors 2026223262   27 Aug 2026 have discovered that, surprisingly, some blood flow access to interstitial tissue does not negate the benefits provided by the fistula.

[0675] Figure 52A may provide partially-circumferential fenestration, in which a certain percentage of the circumference of the stent structure 5208 is bare (not covered by the graft 5209). Figure 52A illustrates the entire length of the device 5200 including the graft 5209. In some examples, only a partial length of the device 5200 includes the graft 5209 (e.g., the proximal segment being bare). In some examples, only a partial length of the device 5200 includes the graft 5209 being partially circumferential (e.g., the proximal segment being partially circumferential) while the remainder of the device 5200 includes a fully circumferential graft 5209. The percentage of bare circumference may be, for example, between about 5% and about 75% (e.g., about 5%, about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, about 75%, ranges between these values, etc.).

[0676] Figure 52Bi is a side view' of still yet another example device 5220 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5220 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5220 may share several of the features of the device 5200 (e.g., first section 5224, second section 5226, stent structure 5228, graft 5229, etc.). The first section 5224 does not extend into the second vessel 5102. Rather, the first section 5224 terminates in the first vessel 5101. In some examples, the proximal end the first section 5224 is substantially longitudinally aligned with the proximal end of the second section 5226 (e.g., as shown in Figure 52Bi). In some examples, the proximal end the first section 5224 is not longitudinally aligned with the proximal end of the second section 5226, for example originating proximal to the proximal end of the second section 5226 or distal to the proximal end of the second section 5226. The second section 5226 extends through interstitial tissue and into the second vessel 5102. The diameter of the second section 5226 may change from the proximal end to the distal end, for example like the tapered or angled stents described herein (e.g., having one or more cylindrical portions and one or more tapered portions).

[0677] The first section 5224 optionally comprises pores 5223 , for example as described with respect to Figure 52A. In some implementations, the first section 5224 may be devoid of pores, because blood can flow through a lumen of the first section 5224 and 2026223262   27 Aug 2026 downstream in the first vessel 5101, as indicated by the arrow 5112. In some implementations, the first section 5224 may comprise a simple structure such as one or more rings or extensions configured to push the second section 5226 against the wall of the first vessel 5101. Blood can flow past the simple structure and downstream in the first vessel 5101.

[0678] Because the second section 5226 extends into the second vessel 5102 regardless of the position of the first section, positioning of the device 5220 may be simplified, for example because rotational orientation generally does not affect function, although a user may prefer that the second section 5226 be adjacent to the second vessel 5102. The first section 5224 may be integral or monolithic with the second section 5226, and they may be deployed at substantially the same time. The first section 5224 may be separate from the second section 5226 such that they may be deployed substantially simultaneously or at least partially separately.

[0679] Figure 52Bii is an example cross-sectional view of the device 5220 of Figure 52Bi across the line 52Bx-52Bx. As described as a possible implementation with respect to Figure 52A, the first section 5224 and the second section 5226 form a figure-8. Figure 52Bii shows the graft 5229 of the second section 5226 inward of the stent structure 5228, although the graft 5229 may be otherwise coupled to the stent structure 5228, have a different stent structure, or be devoid of a stent structure. Although shown as generally circular, the cross-sections of the first section 5224 and the second section 5226 could be oval or have other shapes configured to occupy more of the first vessel 5101 and / or the second vessel 5102 including, for example, semicircular, polygonal, etc.

[0680] Figure 52Biii is another example cross-sectional view of the device 5220 of Figure 52Bi across the tine 52Bx-52Bx. As described as a possible implementation with respect to Figure 52A, the graft 5229 extends across a lumen of the stent structure 5228 to form two flow paths.

[0681] Figure 52Ci is a side view of another example device 5230 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5230 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5230 may share several of the features of the devices 5200, 5220 (e.g., first section 2026223262   27 Aug 2026 5234, second section 5236, stent structure 5238, graft 5239, radiopaque marker 5237, etc.). Like the device 5220, the first section 5234 does not extend into the second vessel 5102. Rather, the first section 5234 terminates in the first vessel 5101. Distal to the branching of the second section 5234, the first section 5234 expands to anchor the first section 5234 in the first vessel 5101. Certain such configurations can provide good anchoring in the first vessel 5101, for example resisting rotation or other forces.

[0682] Figure 52Cii is a cross-sectional view of the device 5230 of Figure 52Ci across the line 52Cii-52Cii. The first section 5234 is crescent or bean shaped around a round shape of the second section 5236. The first section 5234 can revert to a round shape distal to the branching of the second section 5236. Such a cross section is also a possible implementation with respect to the devices 5200, 5210.

[0683] Figure 52D is a side view of yet another example device 5240 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5240 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5240 may share several of the features of the devices 5100, 5230 (e.g., the first section 5244 comprising an uncovered stent, the second section 5246 comprising a graft, etc.), the first section 5244 comprises a tapered portion 5245 configured to narrow from a first diameter to a second diameter smaller than the first diameter. The tapered portion 5245 comprises pores 5243 configured to allow blood to flow around the second section 5406 and continue to flow in the first vessel 5101, as shown by the arrows 5112, Blood that flows into the second section 5246 is diverted into the second vessel 5102, as shown by the arrow 5110. The device 5240 may provide particular advantages in larger vessels (e.g., proximal to occlusions before an artery begins to naturally taper and narrow). The self-centering nature of the device 5240 can provide an all-in-one solution for centering the second section 5246 in a large vessel to permit flow around the second section 5246, while also gathering some of the flow for the second vessel 5102. The tapered section 5425 could substantially center the proximal end of the second section 5246 in the first vessel (e.g., as shown in Figure 52D). The tapered section 5425 could push the proximal end of the second section 5246 to a side of the first vessel (e.g., a side towards the second vessel 5102 (e.g., to reduce occlusion of the 2026223262   27 Aug 2026 first vessel 5101), a side away from the second vessel 5102 (e.g., to reduce a bend angle of the second section 5426).

[0684] The first section 5424 may be integral with the second section 5426. For example, the first section and the second section may share a stent structure that is covered with graft material distal to the tapered portion 5425. The first section 5424 may be separate from the second section 5426 and deployed sequentially. For example, the first section 5424 may be deployed in the first vessel 5101 and then the second section 5426 may be deployed through the first section 5424 with the proximal end of the second section 5426 overlapping the distal end of the first section 5424.

[0685] Figure 53A is a side view of still another example device 5300 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5300 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5300 may share several of the features of the device 5100 or more particularly the second section 5106 (e.g., stent structure 5308, graft 5309, radiopaque markers 5307, etc.). The graft 5309 extends substantially the entire length of the device 5300, although sections proximal and distal to the illustrated device 5300 are also possible. The device 5300 comprises windows or fenestrations 5303 lacking the graft 5309. The graft 5309 may be removed to form the windows 5303, or not formed in the first place. Manufacturing the device 5300 with the windows 5303 may simplify a placement procedure (e.g., deploy the device 5300 and confirm rotational alignment) and / or reduce risk of creating thrombus. In some implementations, the device 5300 may comprise circumferential or spiral slits along at least a segment of the graft 5309 such that when the device 5300 bends the slits separate. Th device 5760 of Figure 57F is one such example. The graft 5309 may overlap to guard against undesired leakage. A segment comprising the bend in the second vessel 5102 is desirably devoid of such slits. Such a configuration may further simplify a placement procedure by automatically opening the windows 5303. The windows 5303 allow blood to flow into the proximal end of the device 5300 into the device 5300, and then from inside the device 5300 to outside the device 5300, and downstream in the first vessel 5101, as indicated by the arrow 5112. Blood that does not exit the windows 5303 may flow into and through the second vessel 5102, as shown by the arrow 5110. The radiopaque marker 5307 may be indicative of 2026223262   27 Aug 2026 a side of the device 5300 comprising the window 5303. An edge or outline or sides or ends of the window 5303 may be marked by a radiopaque marker. The stent structure exposed by the window 5303 may be clad with radiopaque material.

[0686] Figures 53Bi-53Biii illustrate an example method of in situ formation of an example device 5320 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5320 allows at least some blood to continue to flow m the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5320 may share several of the features of the device 5300, but is not manufactured with windows or structure such as slits configured to form windows.

[0687] In Figure 53Bi, a prehminary device 5310 is anchored in the first vessel 5101, extends through interstitial tissue, and is anchored in the second vessel 5102. In this way, the preliminary device 5310 shares many features with many fistula prostheses described herein, and any such prostheses may be used as the preliminary device 5310. A guidewire 5312 extends through a side of the preliminary device 5310. The guidewire 5312 may be navigated from a vasculature access point and puncture through the side of the preliminary device 5310. The guidewire may be integrated with the preliminary device 5310 such that the guidewire 5312 already extends through the side of the preliminary device 5310 after placement of the preliminary' device 5310.

[0688] In Figure 53Bii, an expansion device 5314 (e.g., plain balloon, drug eluting balloon, scoring balloon, expandable filaments, dilator, combinations thereof, etc.) is tracked over the guidewire 5312 and extends through the side of the preliminary device 5310. In some implementations, a fenestration device such as a laser atherectomy tool (e.g,, Turbo Elite®1, available from Spectranetics) may be used. The expansion device 5314 is radially-expanded, as shown by the arrows 5316, to form a large window 5323 (Figure 53Biii) and making the device 5320 in situ. The window 5323 allows blood to flow into the proximal end of the device 5320 into the device 5320, and then from inside the device 5320 to outside the device 5320, and downstream in the first vessel 5101, as indicated by the arrow 5112. Blood that does not exit the window 5323 may flow into and through the second vessel 5102, as shown by the arrow 5110. In some implementations, the expansion device 5314 may comprise a dilator tracked over the guidewire 5312. In some implementations, the guidewire 2026223262   27 Aug 2026 5312 may puncture the side of the preliminary device 5310 to form several small windows, one or more of which may optionally be expanded.

[0689] Figure 53Ci shows an example cell pattern for a stent structure 5348 of a fenestrated device. Figure 53Cii shows an example of the stent structure 5348 of Figure 53Ci partially covered in graft 5349 and including a window 5343. The cell pattern includes a first longitudinal segment 5342, a second longitudinal segment 5344, and a third longitudinal segment 5346. The first longitudinal segment 5342 comprises a first cell pattern configured to anchor in a first vessel (e.g., an artery). The second longitudinal segment 5344 comprises a second cell pattern configured to anchor in a second vessel (e.g., a vein). The third longitudinal segment 5346 is longitudinally between the first longitudinal segment 5346 and the second longitudinal segment 5344. The third longitudinal segment 5346 comprises a third cell pattern configured to be more easily punctured during a fenestration process. For example, the third cell pattern may be more porous than the first cell pattern and / or the second cell pattern. In some implementations, the pores of the third cell pattern are sized for a typical angioplasty balloon (e.g., about 1.5 mm to about 5 mm (e.g., about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 4.5 mm, about 5 mm, ranges between such values, etc.) or about 1.8 mm2 to about 19.6 mm2 (e.g., about 1.8 mm2, about 3.1 mm2, about 4.9 mm2, about 7.1 mm2, about 9.6 mm2, about 12.6 mm2, about 15.9 mm2, about 19.6 mm2, ranges between such values, etc.)) for positioning below' the knee, about 4 mm to about 10 mm (e.g., about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, ranges between such values, etc, .) or about 12.6 mm2 to about 78.5 mm2 (e.g., about 12.6 mm2, about 19.6 mm2, about 28.3 mm2, about 38.5 mm2, about 50.3 mm2, about 63.6 mm2, about 78.5 mm2, ranges between such values, etc.)) for positioning above the knee, etc.). For another example, the third cell pattern may be less dense than the first cell pattern and / or the second cell pattern. For yet another example, the third cell pattern may comprise fewer struts than the first cell pattern and / or the second cell pattern. The reduced amount of metal in the third cell pattern makes the third segment easier to puncture to form the window 5343 in the graft 5349. The third cell pattern may improve hemodynamics (e.g., because less metal is in the flow path shown by the arrow 5112. The first cell pattern may be the same as or different from the second cell pattern. For example, the first cell pattern may have a radial force and / or flexibility configured for placement in an 2026223262   27 Aug 2026 artery and / or the second cell pattern may have a radial force and / or flexibility configured for placement in a vein. The third segment 5344 may be flexible, for example suitable for taking a bend and / or placement in a challenging biomechanical region, (e.g., popliteal, SFA, etc.). In some implementations, the third cell pattern comprises deformable regions with improved elongation and / or elastic properties to facilitate fenestration with reduced or no risk of damage when displaced by expandable member.

[0690] The stent structure 5348 and / or the graft 5349 may comprise one or more radiopaque markers 5347 to demarcate the transition between the first segment 5342 and the third segment 5346 and / or the transition between the second segment 5344 and the third segment 5346. The radiopaque marker 5347 may be coupled to struts of the stent structure 5348, electroplated to the stent structure 5348, woven through the struts of the stent structure 5348, etc. the radiopaque marker 5347 may be radiopaque material incorporated into the graft 5349. The catheter used to deliver the device may comprise one or more corresponding radiopaque markers to facilitate placement.

[0691] Figure 53Di illustrates an example method of in situ formation of an example device providing fluid flow from a first vessel to a second vessel and through the first vessel. The device allows at least some blood to continue to flow m the first vessel, and may provide one or more of the distal arterial flow preservation advantages described herein. The device may share several of the features of the device 5300, but is not manufactured with windows or structure such as slits configured to form windows. In Figure 53Di, a preliminary / device 5360 is anchored in the first vessel, extends through interstitial tissue, and (not shown) is anchored in a second vessel. In this way, the preliminary device 5360 shares many features with many fistula prostheses described herein, and any such prostheses may be used as the preliminary device 5360.

[0692] Figure 53D1 shows an example fenestration device including an expandable member 5362 (e.g,, balloon, temporary stent, etc,), a tapered segment 5364, and a puncturer 5366. The expandable member 5362 is configured to center the device in the vessel and / or to stabilize the device during the application of a fenestration formation force. The expandable member 5362 may comprise, for example, a balloon, a stent mesh, supportive arms, etc. 2026223262   27 Aug 2026

[0693] The tapered segment 5364 is configured to stabilize the puncturer 5366 during the application of a fenestration formation force and / or to be tracked over the puncturer 5366 to expand the window formed by the puncturer 5366. The tapered segment 5364 may include features similar to the CXI® support catheter, available from Cook. The tapered segment 5364 is optionally longitudinally movable relative to the expandable member 5362.

[0694] Figure 53Dii shows an example tapered segment 5374 usable with the device of Figure 53Di. The tapered segment 5374 comprises an angle 5375. When the puncturer 5366 exits the distal end of the tapered segment 5374, the puncturer 5366 follows the angle 5375 and continues straight.

[0695] Figure 53Diii shows another example tapered segment 5384 usable with the device of Figure 53Di. The tapered segment 5384 comprises a lumen 5382. The distal end of the lumen 5382 comprises a ramped surface 5383. When the guidewire exits the distal end of the lumen 5382, the guidewire is deflected by the ramped surface 5383 and extends out of the tapered segment 5384 at an angle 5385 and continues straight. The tapered segment 5384 optionally comprises a straight lumen that exits the distal end of the tapered segment 5384, for example selectable by the user for advancing the guidewire without an angle. The lumen 5382 may comprise different sizes for the angled exit and the straight exit, for example and without limitation, 0.018” (approx. 0.45 mm) for the angled exit and 0.014” (approx. 0.36 mm) for the straight exit).

[0696] The tapered segment 5364, 5374, 5384 enters the small opening created by the puncturer 5366 and expands the hole. The expansion of the hole may complete the fenestration, or may make the hole appropriate for receiving an expandable member. In some implementations, the expandable member 5362 may be collapsed after serving its anchoring function and then used to expand the hole. In some implementations, a different expandable member may be used to expand the hole.

[0697] The puncturer 5366 is configured to puncture the graft of the preliminary device 5360, for example being relatively stiff, having a sharp distal tip, etc. The puncturer 5366 is longitudinally movable relative to the expandable member 5362 and the tapered segment 5364. The puncturer 5366 may comprise a needle or cannula. The puncturer 5366 2026223262   27 Aug 2026 may comprise a reentry device. The puncturer 5366 may comprise an atherectomy device, a laser, a guidewire (e.g., distal tip original or modified (e.g., stiffened and / or sharpened)), etc.

[0698] Figures 53E1 and 53Eii illustrate an example method of aligning a puncturer 5366 for in situ formation of an example device providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device comprises a radiopaque marker 5390, for example as described herein with respect to the radiopaque marker 4210. For example, the marker 5390 may be on one side of a lumen through which a guidewire extends and oriented with respect to the angle of the tapered segment 5374. The marker 5390 may be on the same side as the taper (e.g., as shown in Figures 53Ei and 53Eii). The marker 5390 may be on the opposite side as the taper. The marker 5390 may be parallel to the taper. As described with respect to the marker 4210, the user may utilize the crossing plane to know where the puncturer 5366 will pierce the graft. In some implementations, a target 5392 may be positioned in the first vessel 5101 distal to the device 5360. The target 5392 may comprise, for example, a guidewire, a marking stent, a biodegradable marker, contrast (e.g., pooled proximate an occlusion), etc.

[0699] Figure 54A is a side view of yet still another example device 5400 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5400 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5400 may share several of the features of the device 5140 (e.g., the first section 5404 comprising an uncovered stent, the second section 5406 comprising a graft, etc.) and / or the device 5320 (e.g., the second section 5406 being similar to the device 5320).

[0700] The first section 5404 and the second section 5406 of the device 5400 are separate and deployed sequentially. For example, the second section 5406 may be deployed first. The user may form a window in the second section 5406 (e.g., as described with respect to Figures 53Bi-53Biii) or the second section 5406 may be manufactured with a window. The second section 5406 ay anchor in the first vessel 5101, extend through interstitial tissue, and anchor in the second vessel 5102. The second section 5406 allows blood to flow into and through the second vessel 5102, as shown by the arrow 5110. The first section 5404 may be deployed second, with the distal segment of the first section 5404 extending through the 2026223262   27 Aug 2026 window of the second section 5406. The first section 5404 anchors in the first vessel 5101. Blood can flow into the first section 5404 and continue to flow in the first vessel 5101, as shown by the arrow 5112. The first section 5404 can provide a predictable and / or durable fenestration diameter, which may better preset \ e the fenestration. The stent structure of the first section 5404 is porous, which allows blood to flow into the second section 5406. The proximal and / or distal ends of the first section 5404 and / or the second section 5406 may comprise a radiopaque marker 5407, for example to help a user determine an anchoring position, an amount of overlap, a rotational orientation (e.g., if manufactured with the window), etc. Although Figure 54A shows the proximal end of the first section 5404 as being proximal to the proximal end of the second section 5406, the proximal end of the first section 5404 may be distal to or aligned with the proximal end of the second section 5406. The device 5400 may be considered a bifurcated stent that is formed in situ. The first section 5404 may be a first leg and the second section 5406 may be a second leg.

[0701] Figure 54Bi is a side view of another example device 5410 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5410 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5410 may share several of the features of the device 5400 (e.g., the first section 5404 comprising an uncovered stent, the second section 5406 comprising a graft, etc.). The device 5410 is manufactured with the first section 5414 and the second section 5416 being configured to bifurcate upon deployment of the device 5410. For example, the distal end of the first section 5414 may be configured (e.g., shape set) to remain straight such that the first section 5414 extends out of a window in the second section 5416, which curves into the second vessel 5102, For another example, the first section 5414 may comprise a flap coupled to the second section 5416.

[0702] Figure 54Bii is a side view of another example device 5415 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5415 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5415 may share several of the features of the device 5410. The device 5415 comprises a plurality of flaps 5417. The flaps 5417 can replicate the action of a valve, for 2026223262   27 Aug 2026 example opening (protruding radially outward) under pulsatile flow. The flaps 5417 can comprise graft material (e.g., ePTFE). The flaps 5417 can comprise a structure that acts as a hinge for the radial outward protrusion. The device 5415 can maintain a proper amount of blood flow in each vessel 5101, 5102, and others, for example by regulating the flow into the second vessel 5102 with excess flow and / or pressure being bled off distal in the first vessel 5101. The flaps 5417 can be distributed across a proximal segment of the device 5415 configured to be in the first vessel 5101 (e.g., as shown in Figure 54Bii). The flaps 5417 that appose a vessel wall would not open, but the flaps 5417 that are in a bend of the device 5415 could open. Flaps 5417 that are proximate a branch vessel of the first vessel 5101 could also open to preserve flow into that branch vessel.

[0703] Figure 54C is a side view of yet another example device 5420 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5420 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5420 comprises a first section 5424 and a second section 5426. The second section 5426 may share several features of the second section 5406 of the device 5400 (e.g., a graft and a window 5423). The second section 5426 may comprise two windows 5423, one having a similar function to the window 5323 of the device 5320 (e.g., allowing blood to continue to flow in the first vessel 5101) and one having a similar function to the window of the second section 5406 of the device 5400 (e.g., configured to have the first section 5424 extend therethrough). The second section 5426 may have a single elongate window 5423 that serves both functions. The first section 5424 and the second section 5426 may be separate. For example, the first section 5424 may extend through a side of the second section 5426 (e.g., as described with respect to the device 5400), then anchor in a branch vessel 5425, allowing blood to flow into the device 5420 and through the branch vessel 5425, as shown by the arrow 5114. The first section 5424 may comprise a stent structure to anchor the first section 5424 in the branch vessel 5425. Anchoring the first section 5424 in the branch vessel 5425 can help to anchor and position the entire device 5420. The first section 5424 may comprise a graft to help guide blood into the branch vessel 5425. The device 5420 may lack the first section 5424, in which case blood could flow through the window 5423 into the branch vessel 5425. The first section 5424 and the second section 5426 may be monolithic 2026223262   27 Aug 2026 with the first section 5424 configured to extend from the second section 5426, for example as described with respect to the device 5410. The second section 5426 may lack the window 5423 and the first section 5424 may comprise the window 5423. No matter the precise configuration, the device 5420 maintains fluid flow from the first vessel 5101 into the branch vessel 5425, as shown by the arrow 5114, and through the first vessel 5101, as shown by the arrow 5112, and also diverts fluid flow into the second vessel 5102, as shown by the arrow 5110.

[0704] The devices described herein can be self-expanding, for example comprising shape memory (e.g., superelastic) material that expands upon release from a catheter. The devices described herein can be balloon expandable. For example, if placement accuracy of the device is important, such as at a crossing point of the fistula or near a bifurcation, a balloon expandable device can be expanded only when rotationally and / or longitudinally positioned as desired.

[0705] Figure 55A is a side view' of still another example device 5500 providing fluid flow from a first vessel to a second vessel and through the first vessel. Figure 55B shows the device 5500 of Figure 55A positioned in a first vessel 5101, extending through interstitial tissue, and into a second vessel 5102. The device 5500 does not or only slightly protrudes into the first vessel 5101. Blood flowing through the first vessel 5101 can continue to flow' in the first vessel 5101, as shown by the arrow 5112. Blood flowing through the first vessel 5101 may also be diverted into the second vessel 5102, as shown by the arrow 5110. The device 5500 allows at least some blood to continue to flow' in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5500 may share several of the features of the other devices disclosed herein (e.g., a stent structure, a graft, etc.). The device 5500 comprises a stent with flares or anchoring features 5502 configured to anchor the device 5500 in the first vessel 5101 and an elongate section 5504 configured to extend through interstitial tissue and into the second vessel 5102. The device 5500 may comprise one flare 5502 or a plurality of flares 5502 (e.g., two flares 5502 as shown in Figure 55A). The flares 5502 could be covered or uncovered. The elongate section 5504 is preferably covered. The device 5500 may include a laser cut stent, a woven stent, or a combination thereof, for example as described herein. The flares 5502 and the elongate section 5504 are substantially symmetrical such that rotational alignment of the 2026223262   27 Aug 2026 device 5504 is not needed. In some implementations, a length of the flares 5502 is approximately half of the diameter of the flares 5502, which can help to secure the device 5500 against the first vessel 5101. The flares 5502 of the device 5500 are generally annular.

[0706] Figure 55C show's yet still another example device 5520 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. Blood flowing through the first vessel 5101 can continue to flow in the first vessel 5101, as shown by the arrow 5112. Blood flowing through the first vessel 5101 may also be diverted into the second vessel 5102, as shown by the arrow 5110. The device 5520 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5520 may share several of the features of the device 5500 (e.g., flares or anchoring features 5522, an elongate section 5524, etc.). Figure 551) is a distal end view of the device 5520 of Figure 55C implanted in the first vessel 5101 and the second vessel 5102. The flares 5520 appose a sidewall of the first vessel 5101. The elongate section 5524 apposes sidewalls of the second vessel 5102.

[0707] Figure 55Ei is a top view of a device 5520a sharing features of the device 5520 of Figures 55C and 55D. The device 5520a comprises four flares 5522a projecting radially outward. The flares 5522a are symmetrical about the device 5520a. The flares 5520a each project radially outward by about a radius of the device 5520a. The flares 5520a are wires or struts formed into an arc shape. Such a shape may provide atraumatic anchoring, although tips of the arcs may penetrate or deform the vessel wall.

[0708] Figure 55Eii is a top view of another device 5520b sharing features of the device 5520 of Figures 55C and 55D. The device 5520b comprises four flares 5522b projecting radially outward. The flares 5522b are symmetrical about the device 5520b. The flares 5520b each project radially outward by about half a radius of the device 5520a. The flares 5520b are solid material (e.g., struts cut into the illustrated shape). More material may provide a same amount of anchoring with less length.

[0709] Figure 55F shows yet still another example device 5530 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5530 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The 2026223262   27 Aug 2026 device 5530 may share several of the features of the device 5520 (e.g., flares or anchoring features 5532, an elongate section 5534, etc.).

[0710] Figure 55G is a top view of the device 5530 of Figure 55F. The device 5530 comprises six flares 5532 projecting radially outward. The flares 5532 are asymmetrical or eccentric about the device 5530. Some of the flares 5532 are longer than other flares. Referring again to Figure 55F, the longer flare(s) 5532 may be oriented distally in the first vessel 5101, which can provide an opposition force to a direction of blood flow.

[0711] Figure 56A is a side view of still another example device 5600 providing fluid flow from a first vessel 5101 to a second vessel 5102 and through the first vessel 5101. The device 5600 allows at least some blood to continue to flow in the first vessel 5101, and may provide one or more of the distal arterial flow preservation advantages described herein. The device 5600 may share several features with the prosthesis 540 of Figure 25C (e.g., a plurality of filaments woven into a woven structure, different porosity longitudinal sections, etc.).

[0712] The prosthesis 540 comprises an embodiment comprising a low porosity' first longitudinal section 544 and a high porosity second longitudinal section 546, with other longitudinal sections also possible. The device 5600 may be considered a variation on the prosthesis 540. The device 5600 comprises a first section 5604, a second section 5606, and a third section 5608 between the first section 5604 and the second section 5606. The first section 5604 has a low porosity, for example low enough to divert, flow such as in a flow diverting stent, as described herein. The second section 5606 has a low porosity, for example low enough to divert flow such as in a flow diverting stent as described herein. The first section 5604 and / or the second section 5606 direct blood to flow from the first vessel 5101 into the second vessel 5102, as shown by the arrow 5110. The first section may have higher porosity. The third section 5608 has a porosity that allows blood to continue to flow in the first vessel 5101, as shown by the arrow 5112, The device 5600 may be woven (e.g., as shown in Figure 56). Changes in weave parameters (e.g., braid angle, wire count, etc.) may cause different porosities. The device 5600 may comprise cut struts (e.g., having different cell patterns or other parameters to change porosity). Compared to known flow diverting stents that are placed in neurovasculature, the device 5600 has a larger diameter (e.g., as described for the fistula prostheses described herein) and / or have a conical or tapered shape 2026223262   27 Aug 2026 (e.g., as described for the fistula prostheses described herein). In embodiments in which the device 5600 is woven, the filaments may be larger than neurovascular flow diverting stents (e.g., between about 50 pm and about 100 pm), which can provide durability sufficient to withstand higher flow'’ and pressures associated with peripheral arterial blood flow. Flow diverting structures may be suitable for any of the sections described herein as comprising a graft. The porosity of the device 5600 may permit stent-in-stent deployment, for example for long pathways in interstitial tissue.

[0713] Figure 56B is a graph showing flow through a parent vessel and a side branch with and without a device 5600 of Figure 56A for different values of porosity of the device 5600. The flow rate for the pre-operation side branch is shown by the left-pointing outlined triangle 5610, which is about 0.18 mL / s. The flow rate for the pre-operation distal parent is shown by the right-pointing outlined triangle 5612, which is about 0.2 mL / s. Since the pre-operation points 5610, 5612 do not include a device 5600, the porosity of the absent device 5600 may be considered 100%. The flow rate for the post-operation side branch is shown by the left-pointing filled triangles 5614. The flow rate for the post-operation distal parent is shown by the right-pointing filled triangles 5616. The highest porosity tested was about 89%, which increased the flow in the distal parent to about 0.22 mL / s and reduced the flow in the side branch to about 0.16 mL / s. The lowest porosity tested was about 35%, which increased the flow in the distal parent to about 0.32 mL / s and reduced the flow in the side branch to about 0.07 mL / s. The lower the porosity, the more flow is diverted away from the side branch and to the distal parent, with an inflection point at about 60%. Thus, the porosity of some or all of the device 5600 and / or the devices described below for directing flow below an ankle, can be selected based on a desired amount of flow diversion.

[0714] Figure 57A illustrates an example device 5700 for directing flow below an ankle. The device 5700 may be a flow focalizing stent configured to preferentially direct flow through a lumen of the device 5700. The device 5700 may reduce, inhibit, or prevent steal in veins distal to a direction of reversed blood flow (reversed relative to normal blood flow in veins), for example in a percutaneous deep venous arterialization circuit. Certain features of woven devices described herein, for example the devices 500, 520, 540, may be incorporated into the device 5700. 2026223262   27 Aug 2026

[0715] As discussed herein, one potential advantage to venous arterialization is improving perfusion of oxygenated to the extremities such as the distal foot. Lining veins with devices such as stent grafts (e.g., the stent grafts 1132 described herein) can help to direct flow towards an extremity, but due to current mechanical limitations, stent grafts are generally not indicated for use in smaller vessels or in vessels that experience large mechanical forces. The device 5700 has a design that is robust and flexible enough to withstand biomechanical forces and flex at the ankle. Branch vessels distal to the stent grafts can steal oxygenated blood that is intended to be driven to the distal foot. Near the calcaneus or heel bone, for example, there are a large number of connecting veins that lead to larger return veins of the leg (e.g., saphenous vein). A small amount of steal may provide some benefit, for example maintaining a higher flow rate, which can be better for patency. The device 5700 has a design that is generally drives flow to the distal foot, but may still provide some perfusion to branch vessels, thereby fine tuning the steal.

[0716] The device 5700 comprises a plurality of wires or filaments woven together in a dense pattern. A...

Claims

1. A device for diverting blood flow from a first vessel to a second vessel through interstitial tissue between the first vessel and the second vessel and for maintaining blood flow in the first vessel, the device comprising:a stent structure; anda graft material coupled to at least a portion of the stent structure;wherein the stent structure and the graft material together comprise a stent-graft, wherein the stent-graft defines a lumen, extends along a longitudinal axis, and comprises: a first end portion defining a first opening, wherein the first end portion isconfigured to be positioned in the first vessel, wherein the first end portion includes a flared portion that flares away from the longitudinal axis, and wherein the flared portion is configured to appose a first sidewall of the first vessel to anchor the first end portion in the first vessel such that (a) a first portion of blood flow through the first vessel is routed through the first opening into the lumen and (b) a second portion of the blood flow through the first vessel is routed distally past the first opening;a second end portion defining a second opening, wherein the second end portion is configured to be positioned in the second vessel and to circumferentially appose a second sidewall of the second vessel such that the first portion of the blood flow is routed distally into the second vessel from the lumen through the second opening; anda third portion between the first end portion and the second end portion, wherein the third portion is configured to extend through the interstitial tissue when the flared portion of the first end portion is anchored in the first vessel and the second end portion is positioned in the second vessel.

2. The device of claim 1 wherein the first sidewall extends about a circumference, and wherein the flared portion is configured to appose a portion of the first sidewall that extends only partially about the circumference.2026223262   27 Aug 20263. The device of claim 1 wherein the blood flow through the first vessel is in a direction, and wherein the first end portion is configured to be positioned in the first vessel such that the first opening is non-orthogonal to the direction of the blood flow.

4. The device of claim 1 wherein the flared portion is symmetrical about the longitudinal axis.

5. The device of claim 1 wherein the flared portion is a first flared portion, and wherein the first end portion of the of the stent-graft further comprises a second flared portion that flares away from the longitudinal axis.

6. The device of claim 1 wherein the first vessel is an artery, and wherein the second vessel is a vein.

7. The device of claim 1 wherein, with the stent-graft in an unconstrained expanded state, the third portion has a diameter that increasingly tapers from the first end portion to the second end portion.

8. The device of claim 1 wherein the second opening is larger than the first opening.

9. The device of claim 1 wherein the flared portion of the first end portion is formedonly by the stent structure.

10. The device of claim 1 wherein the first opening is configured to be positioned in a first orientation relative to the first vessel, wherein the second opening is configured to be positioned in a second orientation relative to the second vessel, and wherein the first orientation is different than the second orientation.2026223262   27 Aug 202611. A device for diverting blood flow from a first vessel to a second vessel through interstitial tissue between the first vessel and the second vessel and for maintaining blood flow in the first vessel, the device comprising:a stent structure having a first end portion, a second end portion, and a third portion extending between the first end portion and the second end portion, wherein— the first end portion is configured to be positioned in the first vessel;the first end portion defines a first terminus of the stent structure, wherein the first terminus is configured to circumferentially contact a first sidewall of the first vessel to anchor the first end portion in the first vessel;a diameter of the first end portion at least partially tapers in a direction from the first terminus toward the third portion;the second end portion is configured to be positioned in the second vessel to circumferentially contact a second sidewall of the first vessel to anchor the second end portion in the second vessel; andthe third portion is configured to extend through the interstitial tissue when the first end portion is positioned in the first vessel and the second end portion is positioned in the second vessel; anda graft material coupled only to the intermediate portion and the second end portion of the stent structure such the first end portion is uncovered by graft material, wherein— the graft material defines a lumen extending through the intermediate portion and the second end portion of the stent structure from a first opening at the intermediate portion to a second opening at the second end portion; and the first opening has a diameter smaller than a diameter of the first terminus of the first end portion such that (a) a first portion of blood flow through the first vessel is routed through the first opening into the lumen and to the second opening and (b) a second portion of the blood flow through the first vessel is routed distally past the first opening.

12. The device of claim 11 wherein the diameter of the first opening is smaller than a diameter of the second opening.2026223262   27 Aug 202613. The device of claim 11 wherein the first vessel is an artery, and wherein the second vessel is a vein.

14. The device of claim 11 wherein, with the stent structure in an unconstrained expanded state, the third portion has a diameter that increasingly tapers in diameter in a direction from the first end portion to the second end portion.

15. The device of claim 11 wherein the first opening is configured to be centered within the first vessel when the first end portion is positioned in the first vessel.

16. The device of claim 11 wherein the stent structure comprises a plurality of interconnected struts.

17. The device of claim 11 wherein the first end portion has a frustoconical shape.

18. The device of claim 11 wherein the first end portion has a cylindrical-frustoconicalshape.

19. The device of claim 11 wherein the first end portion is self-centering.

20. The device of claim 11 wherein the first end portion is configured to be positionedwithin the first vessel such that the first opening is offset from a longitudinal axis of the first vessel.

Images