Devices and methods for increasing blood perfusion to distal extremity

Abstract

To provide methods and systems for providing or maintaining fluid flow through body passages such as heart cavities and blood vessels.SOLUTION: 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.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This application relates to methods and systems for use in percutaneous procedures. In particular, this application relates to methods and systems for providing or maintaining fluid flow through body passages such as heart cavities and blood vessels.

[0002] [Incorporation by Reference] This application claims the benefit of priority of U.S. Provisional Patent Application No. 62 / 929,366, filed Nov. 1, 2019; U.S. Provisional Patent Application No. 63 / 044,763, filed Apr. 3, 2020; and U.S. Provisional Patent Application No. 63 / 072,423, filed Sep. 4, 2020. Each of these applications is hereby incorporated by reference in its entirety into this specification.

Background Art

[0003] Minimally invasive percutaneous surgery or “keyhole” surgery is a surgical method in which a surgical device is inserted into a patient's body cavity through a small incision made in the skin. This surgical modality is becoming increasingly popular because it allows the patient to endure less discomfort from the surgery while retaining the advantages of conventional surgery. Patients treated by such surgical methods exhibit a lower degree of discomfort, the need for general anesthesia, trauma, and risk of infection, and can have a significantly shorter recovery time compared to conventional surgical procedures.

[0004] Cardiovascular diseases can be treated using keyhole surgery, for example laparoscopic surgery. When treating cardiovascular diseases, a balloon catheter is usually inserted into an artery near the patient's groin and guided to the patient's heart, where the balloon at the distal portion of the catheter expands to perform balloon angioplasty, which helps to widen or expand the blocked blood vessel and return blood flow to the heart tissue, and can be used as an alternative to open heart surgery to treat a partially blocked coronary artery. A tubular support device (e.g., a stent) can be deployed at the occlusion site to prevent subsequent occlusion (restenosis) or collapse of the blood vessel. The stent may be, for example, an expandable metal mesh tube carried on the balloon of a balloon catheter or self-expanding. A balloon-expandable stent expands when the balloon expands, thereby pressing the stent against the wall of the blood vessel. The stent is configured to retain its expanded shape, for example, by plastic deformation or a mechanical locking mechanism, so as to form an elastic scaffold or elastic support within the blood vessel when it reaches its expanded position. The support structure (e.g., the stent) supports the wall of the blood vessel and expands the wall of the blood vessel to maintain the path through which blood flows through the blood vessel. A self-expanding stent that is held in a collapsed state by a catheter suitably adapted for conveyance through an artery and expands to an expanded state when deployed at the occlusion site is also available. The catheter can have, for example, a holding sleeve that holds the stent in a compressed or non-expanded state. Removing the sleeve from the stent causes the stent to expand and support and expand the wall of the blood vessel.

[0005] For example, in acute cases and when the coronary artery is completely blocked, balloon angioplasty is not always a suitable measure. In these cases, the usual treatment is to use coronary artery bypass. Coronary artery bypass surgery is an open chest or open heart procedure and typically involves transplanting a portion of a healthy blood vessel onto the coronary artery to bypass the blocked portion and return blood flow to the coronary artery tissue. The healthy blood vessel is usually a vein removed from the patient's leg or arm during the bypass surgery. To perform the procedure, the patient's heart must be exposed, resulting in significant surgical trauma, by opening the chest, separating the sternum, and incising the pericardium around the heart.

[0006] Conventional coronary artery bypass surgery is not always elective. Some patients are at low risk of recovery or at high risk of significant trauma due to surgery, have a high risk of infection, have no healthy blood vessels to use as bypass grafts, have significant comorbidities, and are expected to have a long and complicated recovery time associated with open-chest surgery, making them unsuitable candidates for conventional coronary artery bypass surgery. For example, factors such as diabetes, old age, obesity, and smoking may exclude some candidate patients who truly need such treatment. SUMMARY OF THE INVENTION

[0007] The present application provides methods and systems that overcome some of the deficiencies and / or improve percutaneous methods and systems. For example, according to some embodiments, the methods and systems described herein can improve the targeting and localization of therapy administration and advantageously enable percutaneous treatment of patients who are ineligible for more invasive surgeries. Some embodiments described herein can provide fluid flow within a passageway such as a coronary vessel and / or a peripheral vessel by creating a bypass using minimally invasive percutaneous surgical techniques.

[0008] In some examples, the delivery catheter for targeting a second vessel from a first vessel includes a catheter having a proximal portion and a distal portion that includes a flat radiopaque marker. The radiopaque marker can be rectangular. The catheter can include a needle aperture. The catheter can include a needle configured to extend through the needle aperture.

[0009] The distal portion of the catheter may be curved. The marker may not follow the curvature of the distal portion of the catheter. The needle aperture may be proximal to the marker. The needle aperture may be distal to the marker. The needle aperture may at least partially overlap the marker.

[0010] The needle opening may be on the first side of the distal portion of the catheter. The marker may be on the second side of the distal portion of the catheter. The first side may be the same as the second side. The first side may be opposite the second side. The distal end of the needle extending from the needle opening can be longitudinally aligned with the radiopaque marker. The needle can include a profile. The needle can slide through the needle lumen. The needle lumen can include a shape complementary to the profile (e.g., to reduce the longitudinal movement of the needle during advancement of the needle).

[0011] The marker can include a first radiopaque material and a second radiolucent material coupled to the first radiopaque material. The second radiolucent material can be coupled to the first radiopaque material by one or more of cladding, plating, chemical vapor deposition, atomic layer deposition, screen printing, coating, adhesion, or sputtering. The second radiolucent material can be polished or planarized after being coupled to the first radiopaque material.

[0012] The ratio of the length of the marker to the width of the marker can be from 1 / 1 to 5 / 1.

[0013] The marker can have a thickness of from 0.001 mm to 1 mm. The marker can have a thickness of from 1 nm to 10 μm.

[0014] The kit can include a delivery catheter and a target catheter. The target catheter can include an expandable member. The expandable member can include a snare. The expandable member can include a mesh. The expandable member can include a radiopaque material. The target catheter can include a first radiopaque marker. The target catheter can include a second radiopaque marker longitudinally spaced from the first radiopaque marker.

[0015] In some examples, an emission catheter for targeting a second blood vessel from a first blood vessel includes a catheter having a proximal portion and a distal portion that includes a needle aperture and a flat rectangular radiopaque marker. The flat rectangular radiopaque marker disappears under fluoroscopy when rotated and provides information regarding the rotational alignment of the emission catheter. The emission catheter further includes a needle configured to extend through the needle aperture.

[0016] In some examples, the catheter includes a flat radiopaque marker. The catheter can be a delivery catheter for targeting a second blood vessel from a first blood vessel. The catheter can include a distal portion that includes a flat radiopaque marker. The radiopaque marker can be rectangular. The catheter can include a needle opening. The catheter can include a needle configured to extend through the needle opening. The distal portion of the catheter can be curved. The marker need not follow the curvature of the distal portion of the catheter. The needle opening can be proximal to the marker. The needle opening can be distal to the marker. The needle opening can at least partially overlap the marker. The needle opening can be on a first side of the distal portion of the catheter. The marker can be on a second side of the distal portion of the catheter. The first side can be the same as the second side. The first side can be opposite the second side. The distal end of the needle extending from the needle opening can be longitudinally aligned with the radiopaque marker. The needle can include a profile. The needle can slide through a needle lumen. The needle lumen can include a shape complementary to the profile (e.g., to reduce longitudinal movement of the needle during advancement of the needle). The kit can include a delivery catheter and a target catheter. The target catheter can include an expandable member. The expandable member can include a snare. The expandable member can include a mesh. The expandable member can include a radiopaque material. The target catheter can include a first radiopaque marker. The target catheter can include a second radiopaque marker longitudinally spaced from the first radiopaque marker.

[0017] In some examples, a method of aligning a catheter includes rotating the catheter within a first blood vessel. The catheter includes flat radiopaque markers. The rotation is performed until the markers have a thickness indicative of the rotational alignment of the catheter. The thickness can be viewed under fluoroscopy. The thickness can be less than a certain value. The thickness can be indicated by a thin (e.g., minimum thickness) line. The radiopaque markers can be rectangular.

[0018] This method can include rotating the catheter within the first blood vessel until the markers have a thickness (e.g., minimum thickness) and strike the side of the catheter as viewed under fluoroscopy. This method can further include advancing the catheter longitudinally until the markers are proximate to a second catheter within a second blood vessel. The second catheter can include radiopaque features visible under fluoroscopy. The radiopaque features of the second catheter visible under fluoroscopy can include expandable members. The expandable members can include snares. The expandable members include a mesh.

[0019] This method can further include extending a needle from the catheter after rotating the catheter. Extending the needle from the catheter can include exiting the first blood vessel and entering a second blood vessel different from the first blood vessel. Alignment of the catheter can include alignment of the needle. Extending the needle from the catheter can include traversing interstitial tissue between the first and second blood vessels.

[0020] This method can further include extending a guide wire through a needle into a second blood vessel. This method can further include threading the guide wire onto a second catheter within the second blood vessel. Threading the guide wire can include occluding an expandable member of the second catheter. This method can further include moving the second catheter to detect corresponding movement of the guide wire. This method can further include moving the second catheter to move the guide wire through the second blood vessel.

[0021] The catheter system can include a tubular body and at least one of a targeting system coupled to the tubular body, an expandable member, or a fluid injection port.

[0022] In some embodiments, a catheter system for identifying a branch within a blood vessel includes a tubular body, a targeting system coupled to the tubular body, an expandable member configured to occlude an expanded blood vessel when juxtaposed against the sidewall of the blood vessel, and a fluid injection port configured to inject a radiopaque fluid into the blood vessel proximal to the expandable member in an expanded state such that the radiopaque fluid pools proximate to the expandable member and provides visualization of the blood vessel and branching blood vessels, or consists essentially of these.

[0023] The expandable member can be coupled to the tubular body. The tubular body can include a fluid injection port. The catheter system can further include a second tubular body. The expandable member can be coupled to the second tubular body. The second tubular body can include a fluid injection port. The targeting system can include an ultrasonic transducer. The targeting system can include an omnidirectional ultrasonic transducer.

[0024] In some embodiments, the catheter system includes a tubular body, a targeting system coupled to the tubular body, and an expandable member, or consists essentially of these.

[0025] The expandable member can be coupled to the tubular body. The catheter system can further include a second tubular body. The expandable member can be coupled to the second tubular body. The expandable member may be configured to juxtapose the side wall of a blood vessel to occlude the blood vessel. The catheter system can further include a fluid injection port. The tubular body can include a fluid injection port. The catheter system can further include a second tubular body that includes a fluid injection port. The targeting system can include an ultrasonic transducer. The targeting system can include an omnidirectional ultrasonic transducer.

[0026] In some embodiments, the catheter system includes, or consists essentially of, a tubular body, a targeting system coupled to the tubular body, and a fluid injection port.

[0027] The tubular body can include a fluid injection port. The catheter system can further include a second tubular body that includes a fluid injection port. The catheter system can further include an expandable member. The expandable member can be coupled to the tubular body. The catheter system can further include a second tubular body. The expandable member can be coupled to the second tubular body. The expandable member may be configured to juxtapose the side wall of a blood vessel to occlude the blood vessel. The targeting system can include an ultrasonic transducer. The targeting system can include an omnidirectional ultrasonic transducer.

[0028] In some embodiments, the catheter system includes, or consists essentially of, a tubular body, a fluid injection port, and an expandable member.

[0029] The tubular body can include a fluid injection port. The catheter system can further include a second tubular body that includes a fluid injection port. The expandable member can be coupled to the tubular body. The catheter system can further include a second tubular body. The expandable member can be coupled to the second tubular body. The expandable member may be configured to juxtapose the sidewall of the blood vessel to occlude the blood vessel. The catheter system can further include a targeting system. The targeting system can include an ultrasonic transducer. The targeting system can include an omnidirectional ultrasonic transducer. A method of identifying a branch can include inserting the catheter system into a first blood vessel, positioning the catheter system at a first location, expanding the expandable member to occlude the first blood vessel, and delivering a contrast agent to the first blood vessel. The contrast agent can pool near the expandable member. The method can further include reviewing the shape of the contrast agent within the first blood vessel under fluoroscopy.

[0030] In some embodiments, a method of identifying a branch includes, or consists essentially of, inserting the catheter system into a first blood vessel and positioning the catheter system at a first location. The catheter system includes an expandable member and a fluid injection port. The method further includes expanding the expandable member to occlude the first blood vessel and delivering a contrast agent from the fluid injection port. The contrast agent pools near the expandable member. The method further includes reviewing the shape of the contrast agent within the first blood vessel under fluoroscopy.

[0031] A single catheter can include an expandable member and a fluid injection port. The first catheter can include the expandable member, and the second catheter can include the fluid injection port. Expanding the expandable member can include providing a flow of fluid through an inflation lumen when in fluid communication with the expandable member. Expanding the expandable member can include expanding a first blood vessel. The contrast agent can include at least one of an iodine-based contrast agent and a barium sulfate-based contrast agent. Delivering the contrast agent can include expanding the first blood vessel. Reviewing the shape of the contrast agent can include identifying the presence of at least one of a bifurcation and a branch vessel. The method can further include repositioning the catheter system if at least one of a bifurcation and a branch vessel is present. The method can further include extending a needle from another catheter within a second blood vessel if at least one of a bifurcation and a branch vessel is absent. Extending the needle can include exiting the second blood vessel, traversing the interstitial tissue between the second and the first blood vessels, and entering the first blood vessel. The method can further include advancing a guidewire through the needle. The catheter system can include a capture element configured to guide the guidewire into a guidewire lumen.

[0032] The catheter system can include a targeting system. Positioning the catheter system at a first location can include targeting the targeting system from a complementary targeting system on another catheter within a second blood vessel. The targeting system can include an ultrasonic receiver. The complementary targeting system can include an ultrasonic emitter. The ultrasonic receiver can include an omnidirectional ultrasonic transducer. The ultrasonic emitter can include a directional ultrasonic transducer. The method can further include enlarging a fistula.

[0033] This method can further include at least partially deploying a prosthesis at a fistula between a second blood vessel and a first blood vessel. After deploying the prosthesis, blood may be diverted from the first blood vessel through the prosthesis to the second blood vessel. This method can further include lining the first blood vessel with a stent graft that includes covering collateral blood vessels of the first blood vessel after deploying the prosthesis. Lining the first blood vessel with a stent graft can include lining the first blood vessel with a plurality of stent grafts. Lining the first blood vessel with a plurality of stent grafts can include first deploying the most distal stent graft of the plurality of stent grafts and last deploying the most proximal stent graft of the plurality of stent grafts. After lining the first blood vessel with a plurality of stent grafts, the proximal edge of the most distal stent graft of the plurality of stent grafts can overlap the distal edge of the next most distal stent graft of the plurality of stent grafts. After lining the first blood vessel with a plurality of stent grafts, the proximal edge of the most proximal stent graft of the plurality of stent grafts can overlap the distal edge of the prosthesis.

[0034] This method can further include disabling a valve within a first blood vessel. Disabling the valve within the first blood vessel can be after lining the blood vessel with a stent graft. Disabling the valve within the first blood vessel can include advancing a retrograde valvulotome through a prosthesis and advancing the retrograde valvulotome of the first blood vessel distally to disable the valve. Disabling the valve within the first blood vessel can include advancing a bidirectional valvulotome adjacent to the valve in a radially compressed state, radially expanding the bidirectional valvulotome to a radially expanded state, advancing the bidirectional valvulotome distally to disable the valve in the radially expanded state, and at least one of retracting the bidirectional valvulotome proximally within the first blood vessel. Radially expanding the bidirectional valvulotome can include at least one of retracting the sheath proximally and advancing the bidirectional valvulotome distally. A method of disabling a valve within a blood vessel can include advancing a bidirectional valvulotome adjacent to the valve in a radially compressed state, radially expanding the bidirectional valvulotome to a radially expanded state, advancing the bidirectional valvulotome distally within the blood vessel to disable the valve in the radially expanded state, and at least one of retracting the bidirectional valvulotome proximally.

[0035] In some embodiments, a method of modifying a blood vessel that includes disabling a valve within the blood vessel and covering collateral blood vessels of the blood vessel includes, consists essentially of, or consists of lining the blood vessel with a stent graft that covers the collateral blood vessels of the blood vessel and disabling the valve within the blood vessel after lining the blood vessel with the stent graft.

[0036] This method can further include at least partially deploying a prosthesis at a fistula between a second blood vessel and a blood vessel. After deploying the prosthesis, blood may be diverted from the second blood vessel through the prosthesis to the blood vessel. Lining the blood vessel with a stent graft can be done after deploying the prosthesis. This method can further include enlarging the fistula. This method can further include advancing a needle from the second blood vessel to the blood vessel to form the fistula. Advancing the needle can include targeting a first catheter within the blood vessel by a second catheter within the second blood vessel. The second catheter can include an ultrasonic emitter. The first catheter can include an ultrasonic receiver. Targeting the catheter within the blood vessel by the catheter within the second blood vessel can include targeting the ultrasonic receiver by the ultrasonic emitter. This method can further include advancing a guidewire through the needle. The catheter system within the blood vessel can include a capture element configured to guide the guidewire into a guidewire lumen. Lining the blood vessel with a stent graft can include lining the blood vessel with a plurality of stent grafts. Lining the blood vessel with a plurality of stent grafts can include first deploying the most distal stent graft of the plurality of stent grafts and last deploying the most proximal stent graft of the plurality of stent grafts. After lining the blood vessel with a plurality of stent grafts, the proximal edge of the most distal stent graft of the plurality of stent grafts can overlap the distal edge of the next most distal stent graft of the plurality of stent grafts. After lining the blood vessel with a plurality of stent grafts, the proximal edge of the most proximal stent graft of the plurality of stent grafts can overlap the distal edge of the prosthesis within the fistula. Inactivating a valve within the blood vessel can include advancing a retrograde valvulotome within the blood vessel distally to disable the valve.Inactivating a vascular valve can include at least one of advancing a bidirectional valvulotome proximate to the valve in a radially compressed state, radially expanding the bidirectional valvulotome to a radially expanded state, advancing the bidirectional valvulotome distally to disable the valve in a radially expanded state, and retracting the bidirectional valvulotome proximally within the blood vessel. Radially expanding the bidirectional valvulotome can include at least one of retracting the sheath proximally and advancing the bidirectional valvulotome distally. This method can further include promoting retrograde perfusion of blood to the toes. Promoting retrograde perfusion of blood to the toes can include expanding a first expandable member of the medial plantar vein to occlude the medial plantar vein. Promoting retrograde perfusion of blood to the toes can include expanding a second expandable member of the lateral plantar vein to occlude the lateral plantar vein. Promoting retrograde perfusion of blood to the toes can include increasing the hydrostatic pressure in the deep plantar venous arch. Increasing the hydrostatic pressure in the deep plantar venous arch can include inactivating a venous valve and allowing retrograde blood flow into the metatarsal veins.

[0037] In some embodiments, a method of promoting retrograde perfusion of blood to the toes includes, consists essentially of, or consists of expanding a first expandable member of the medial plantar vein to occlude the medial plantar vein and increasing the hydrostatic pressure in the deep plantar venous arch. Increasing the hydrostatic pressure in the deep plantar venous arch can include inactivating a venous valve and allowing retrograde blood flow into the metatarsal veins. This method can further include expanding a second expandable member within the lateral plantar vein to occlude the lateral plantar vein.

[0038] In some embodiments, a catheter system for promoting retrograde perfusion of blood to the toes includes, or consists essentially of, a first catheter including a first expandable member configured to expand within the medial plantar vein to occlude the medial plantar vein, and a second catheter including a second expandable member configured to expand within the lateral plantar vein to occlude the lateral plantar vein.

[0039] The first catheter can be movable longitudinally through the second catheter and the second expandable member. The first catheter can include an inflation lumen in fluid communication with the first expandable member. The second catheter can include an inflation lumen in fluid communication with the second expandable member. The first catheter may be configured to curve around the lateral plantar vein and towards the medial plantar vein.

[0040] In some embodiments, a bidirectional valvulotome includes, or consists essentially of, a proximal portion, a distal portion, and a longitudinal intermediate portion between the proximal and distal portions. The intermediate portion includes a blade facing distally and a blade facing proximally.

[0041] The intermediate portion can include struts that include a distally facing blade and a proximally facing blade. The intermediate portion can include a plurality of struts. One of the plurality of struts can include a distally facing blade and a proximally facing blade. Each strut of the plurality of struts can include a distally facing blade and a proximally facing blade. At least one of the plurality of struts can include a distally facing blade. At least one of the plurality of struts can include a proximally facing blade. The intermediate portion can include three struts. The three struts can be circumferentially spaced apart equally. The intermediate portion can be made radially expandable. The intermediate portion can self-expand when released from a sheath. The proximal portion can be coupled to a pusher element. The intermediate portion can be laser cut (e.g., from a hypotube or sheet). At least one of the distally facing blade and the proximally facing blade can be rotated relative to the circumference of the intermediate portion.

[0042] In some embodiments, a method of disabling a valve within a blood vessel comprises advancing a bidirectional valvulotome proximate to the valve in a radially compressed state, radially expanding the bidirectional valvulotome to a radially expanded state, advancing the bidirectional valvulotome distally within the blood vessel to disable the valve in the radially expanded state, and at least one of retracting the bidirectional valvulotome proximally, or consisting essentially of those.

[0043] Advancing the bidirectional valvulotomy knife adjacent to the valve can include advancing the bidirectional valvulotomy knife in a direction opposite to the original fluid flow. Advancing the bidirectional valvulotomy knife adjacent to the valve can include advancing the bidirectional valvulotomy knife in the direction of the original fluid flow. Advancing the bidirectional valvulotomy knife adjacent to the valve can include advancing the bidirectional valvulotomy knife proximal to the valve. Advancing the bidirectional valvulotomy knife adjacent to the valve can include advancing the bidirectional valvulotomy knife distal to the valve.

[0044] In some embodiments, a catheter for capturing a guidewire comprises, or consists essentially of, a catheter body, a capture element, and a guidewire lumen in communication with the capture element.

[0045] The capture element can be configured to deploy from the distal end of the catheter body. The capture element can be configured to deploy from the side of the catheter body. The capture element can have a collapsed state and an expanded state. The capture element can include a shape memory material configured to change to the expanded state at body temperature. The capture element can have an angle of 110° to 150° in the expanded state. The guidewire lumen can include an expanded portion proximate to the capture element. The catheter can further include an expandable element configured to expand the capture element. The expandable element can include an inflatable member. The catheter body can include an inflation lumen in fluid communication with the inflatable member. The expandable element can be movable relative to the catheter body.

[0046] In some embodiments, the method of disabling a valve comprises, or alternatively consists essentially of, forming a fistula between a first blood vessel and a second blood vessel. The first blood vessel can be an artery. The second blood vessel can be a vein. Forming the fistula includes inserting a first catheter into the first blood vessel. The first catheter comprises an ultrasound emitting transducer and a needle configured to extend radially from the first catheter. Forming the fistula further includes inserting a second catheter into the second blood vessel. The second catheter comprises an ultrasound receiving transducer. Forming the fistula further includes transmitting an ultrasonic signal from the ultrasound emitting transducer and, after receiving the ultrasonic signal by the ultrasound receiving transducer, extending the needle from the first catheter. Extending the needle includes exiting the first blood vessel, traversing interstitial tissue between the first and second blood vessels, and entering the second blood vessel. The method further includes at least partially deploying a prosthesis at the fistula. After deploying the implantable prosthesis, blood is diverted from the first blood vessel through the prosthesis to the second blood vessel. The method further includes disabling a valve within the second blood vessel. Disabling the valve within the second blood vessel includes excising the valve using a retrograde valvulotome and lining the second blood vessel with a stent.

[0047] The stent can comprise a covering or a graft. Lining the second blood vessel can include covering collateral blood vessels of the second blood vessel. The stent can be separate from the prosthesis. The stent can be spaced apart from the prosthesis along the length of the second blood vessel. The stent can be integral with the prosthesis.

[0048] In some embodiments, the method of disabling a valve includes, or alternatively consists essentially of, forming a fistula between a first blood vessel and a second blood vessel. Forming the fistula includes inserting a catheter into the first blood vessel. The catheter comprises a needle configured to extend radially from a first catheter. Forming the fistula further includes extending the needle from the first catheter. Extending the needle includes exiting the first blood vessel, traversing interstitial tissue between the first and second blood vessels, and entering the second blood vessel. The method further includes at least partially deploying a prosthesis in the fistula between the first and second blood vessels. After deploying the implantable prosthesis, blood is diverted from the first blood vessel through the prosthesis to the second blood vessel. The method further includes disabling a valve within the second blood vessel. Disabling the valve within the second blood vessel includes at least one of excising the valve using a retrograde valvulotome, inflating a balloon, expanding a temporary stent, and lining the second blood vessel with an implantable stent.

[0049] The implantable stent can comprise a covering or a graft. Lining the second blood vessel can include covering collateral blood vessels of the second blood vessel. The implantable stent can be separate from the prosthesis. The implantable stent can be integral with the prosthesis. The first catheter can comprise an ultrasonic transmission transducer. Forming the fistula can include inserting a second catheter comprising an ultrasonic reception transducer into the second blood vessel, transmitting an ultrasonic signal from the ultrasonic transmission transducer, receiving the ultrasonic signal by the ultrasonic reception transducer, and then extending the needle from the first catheter.

[0050] In some embodiments, a method of disabling a valve includes, or alternatively consists essentially of, deploying a prosthesis at least partially at a fistula between a first blood vessel and a second blood vessel. After deploying the implantable prosthesis, blood is diverted from the first blood vessel through the prosthesis to the second blood vessel. The method further includes disabling a valve within the second blood vessel.

[0051] Disabling a valve within the second blood vessel can include excising the valve using a retrograde valvulotome. Disabling a valve within the second blood vessel can include lining the second blood vessel with a stent. The stent can comprise a covering or a graft. Lining the second blood vessel can include covering collateral blood vessels of the second blood vessel. The stent can be separate from the prosthesis. The stent can be spaced apart from the prosthesis along the length of the second blood vessel. A proximal segment of the stent can overlap a distal segment of the prosthesis longitudinally. The stent can be integral with the prosthesis. Disabling a valve within the second blood vessel can include excising the valve using a retrograde valvulotome and lining the second blood vessel with a stent. Disabling a valve within the second blood vessel can include at least one of inflating a balloon and expanding a temporary stent. Disabling a valve within the second blood vessel can include inflating a balloon. Disabling a valve within the second blood vessel can include expanding a temporary stent.

[0052] In some embodiments, an implantable prosthesis for treating an occlusion in a first blood vessel comprises a plurality of filaments woven into a fabric structure, a proximal end, a distal end, a sidewall between the proximal end and the distal end, a lumen defined by the sidewall, and a porosity sufficient to direct fluid flow through the lumen without substantially perfusing through the sidewall, or alternatively consists essentially of a plurality of filaments woven into a fabric structure, a proximal end, a distal end, a sidewall between the proximal end and the distal end, a lumen defined by the sidewall, and a porosity sufficient to direct fluid flow through the lumen without substantially perfusing through the sidewall.

[0053] The porosity can be from about 0% to about 50%. The porosity can be from about 5% to about 50%. The prosthesis may not substantially include a graft material. The prosthesis can have a first longitudinal segment having the above porosity and a second longitudinal segment having a second porosity different from the above porosity. The second longitudinal segment can have parameters different from those of the first longitudinal segment. The parameters can include at least one of a braiding angle, a filament diameter, a filament material, a woven structure diameter, a woven structure shape, and an auxiliary support structure. The prosthesis can further have a third longitudinal segment between the first longitudinal segment and the second longitudinal segment. The third longitudinal segment can have parameters different from those of at least one of the first longitudinal segment and the second longitudinal segment. The parameters can include at least one of a braiding angle, a filament diameter, a filament material, a woven structure diameter, a woven structure shape, and an auxiliary support structure. The prosthesis can further include an auxiliary support structure. The auxiliary support structure can include a second plurality of filaments woven together into a second woven structure and including a second plurality of filaments having parameters different from those of the plurality of filaments. The parameters can include at least one of a braiding angle, a filament diameter, a woven structure diameter, and a filament material. The auxiliary support structure can include a cut hypo tube. The plurality of filaments can include filaments containing a shape memory material (such as nitinol) and a prosthesis containing a biocompatible polymer (such as Dacron®, Kevlar®).

[0054] In some embodiments, an implantable prosthesis for treating an occlusion in a first blood vessel comprises a proximal end, a distal end, a sidewall between the proximal end and the distal end, a lumen defined by the sidewall, a first longitudinal section configured to be disposed within a first lumen, a second longitudinal section configured to be disposed within a second lumen, and a third longitudinal section between the first longitudinal section and the second longitudinal section, or alternatively consists essentially of a proximal end, a distal end, a sidewall between the proximal end and the distal end, a lumen defined by the sidewall, a first longitudinal section configured to be disposed within a first lumen, a second longitudinal section configured to be disposed within a second lumen, and a third longitudinal section between the first longitudinal section and the second longitudinal section. At least one of the first longitudinal section and the third longitudinal section has a porosity sufficient to direct fluid flow through the lumen without substantially perfusing through the sidewall.

[0055] The porosity can be from about 0% to about 50%. The porosity can be from about 5% to about 50%. The prosthesis may not substantially include a graft material. The second longitudinal segment can have parameters different from those of the first longitudinal segment. The parameters can include at least one of the braiding angle, filament diameter, filament material, diameter, shape, and auxiliary support structure. The third longitudinal segment can have a second porosity different from the above porosity. The first longitudinal segment can be balloon-expandable. The second longitudinal segment can be self-expanding. The prosthesis can include a plurality of filaments woven together into a woven structure. The plurality of filaments can include filaments containing a shape memory material (such as nitinol) and a prosthesis containing a biocompatible polymer (such as Dacron®, Kevlar®). The third longitudinal section can have parameters different from at least one of the first longitudinal section and the second longitudinal section. The parameters can include at least one of the braiding angle, filament diameter, filament material, diameter, shape, and auxiliary support structure. The prosthesis can further include an auxiliary support structure. The first longitudinal section can be substantially cylindrical and can have a first diameter, the second longitudinal section can be substantially cylindrical and can have a second diameter larger than the first diameter, the third longitudinal section can be frustoconical, and can be tapered from the first diameter to the second diameter. The first longitudinal section can be substantially cylindrical and can have a first diameter, the second longitudinal section and the third longitudinal section can be frustoconical, and can be tapered from the first diameter to a second diameter larger than the first diameter.

[0056] In some embodiments, an implantable prosthesis for treating an occlusion in a first blood vessel comprises a plurality of filaments woven into a textile structure, a proximal end, a distal end, a sidewall between the proximal end and the distal end, a lumen defined by the sidewall, and a porosity of about 5% to about 50%.

[0057] The porosity can be configured to direct fluid flow to pass substantially through the lumen. The prosthesis can have a first longitudinal segment having the porosity and a second longitudinal segment having a second porosity different from the porosity.

[0058] In some embodiments, the kit comprises a prosthesis and a fistula formation system. The kit can further comprise a valvuloplasty device. In some embodiments, the kit comprises a prosthesis and a valvuloplasty device. The kit can comprise a prosthesis delivery system including the prosthesis. In some embodiments, the method includes deploying a prosthesis at a fistula between a first blood vessel and a second blood vessel. The valvuloplasty device can include a retrograde valvulotome. The valvuloplasty device can include a balloon. The valvuloplasty device can include a venous stent. The venous stent can comprise a covering or a graft. The venous stent can be integral with the prosthesis.

[0059] In some embodiments, a method of redirecting fluid flow from a first blood vessel including an occlusion to a second blood vessel includes at least partially deploying a prosthesis at a fistula between the first blood vessel and the second blood vessel. The prosthesis comprises a plurality of filaments woven into a textile structure and having a porosity of less than about 50%. After deploying the implantable prosthesis, blood can be redirected from the first blood vessel to the second blood vessel through the prosthesis.

[0060] The first blood vessel can be an artery. The conduit can be a vein. The method can include expanding the fistula. The first blood vessel can be substantially parallel to the second blood vessel. Deploying the prosthesis can include self-expanding the prosthesis. Deploying the prosthesis can include the balloon expanding the prosthesis. Deploying the prosthesis can include deploying the woven structure and deploying the auxiliary support structure. Deploying the auxiliary support structure can be performed before deploying the woven structure. Deploying the auxiliary support structure can be performed after deploying the woven structure. The auxiliary support structure can include a second plurality of filaments woven into the second woven structure. The auxiliary support structure can include a cut hypotube. The method can further include forming a fistula. Forming the fistula can include inserting a firing catheter into the first blood vessel and inserting a target catheter into the second blood vessel. The firing catheter can include an ultrasonic transmission transducer and a needle configured to extend radially from the firing catheter. The target catheter can include an ultrasonic reception transducer. Forming the fistula can include transmitting an ultrasonic signal from the ultrasonic transmission transducer and rotating and longitudinally moving the firing catheter at least one of which until the ultrasonic signal can be received by the ultrasonic reception transducer while the ultrasonic signal is being transmitted, and after the ultrasonic signal is received by the ultrasonic reception transducer, extending the needle from the firing catheter, and extending the needle can include exiting the first blood vessel, traversing the interstitial tissue between the first blood vessel and the second blood vessel, and entering the second blood vessel. The method can further include disabling a valve in the second blood vessel. Disabling the valve in the second blood vessel can include excising the valve using a retrograde valvulotome. Disabling the valve in the second blood vessel can include inflating a balloon.Inactivating the valve in the second blood vessel can include expanding a stent. Inactivating the valve in the second blood vessel can include lining the second blood vessel with a stent. The stent can comprise a coating or a graft. Lining the second blood vessel can include covering the collateral vessels of the second blood vessel. The stent can be separate from the prosthesis. The stent can be spaced apart from the prosthesis along the length of the second blood vessel. The end of the stent can abut the end of the prosthesis. A portion of the stent can overlap a portion of the prosthesis in the longitudinal direction. The above portion of the stent can be radially inside the above portion of the prosthesis. The method can include expanding the stent after deploying the prosthesis. The above portion of the prosthesis can be radially inside the above portion of the stent. The method can include expanding the stent before deploying the prosthesis. The stent can be integral with the prosthesis.

[0061] In some embodiments, an implantable prosthesis that maintains the patency of an anastomosis between an artery and a vein in the lower extremity has a first section configured to remain in the lower extremity artery, a second section configured to remain in the lower extremity vein, and a third section between the first and second sections in the longitudinal direction. The third section is configured to maintain the patency of the anastomosis between the artery and the vein.

[0062] The first section can be configured to juxtapose the walls of the lower limb artery. The first section can have a return. The second section can be configured to juxtapose the walls of the lower limb vein. The second section can have a return. At least one of the first section, the second section, and the third section can be self-expanding. At least one of the first section, the second section, and the third section can be balloon-expandable. The length of the second section can be greater than the length of the first section. The second section can be configured to disable the valve within the lower limb vein. The second section can be configured to cover the collateral vessels of the lower limb vein.

[0063] In some embodiments, a method of redirecting fluid flow from a first blood vessel to a second blood vessel in the lower limb includes forming a hole between the first blood vessel and the second blood vessel and expanding the hole to form an anastomosis.

[0064] Forming the hole can include advancing a wire from a first blood vessel into a second blood vessel. Forming the hole can include transecting a needle from a first blood vessel into a second blood vessel. Expanding the hole can include expanding the hole using at least one balloon. Expanding the hole can include using a plurality of balloons having successively larger diameters. A first balloon of the plurality of balloons can have a diameter of about 1.5 mm, and a last balloon of the plurality of balloons can have a diameter of about 3 mm. The plurality of balloons can include a first balloon having a diameter of about 1.5 mm, a second balloon having a diameter of about 2.0 mm, a third balloon having a diameter of about 2.5 mm, and a third balloon having a diameter of about 3.0 mm. Expanding the hole using a plurality of balloons can include using successively higher balloon inflation pressures. The method may not include (e.g., without using a stent, graft, scaffold, or other prosthesis) placing a prosthesis (e.g., may lack or exclude placing a prosthesis). The positions of the first blood vessel and the second blood vessel can be substantially maintained by the anatomical structures surrounding the first blood vessel and the second blood vessel. The method can further include placing a prosthesis at the anastomosis. Placing a prosthesis at the anastomosis can include implanting the prosthesis within at least one of the first blood vessel and the second blood vessel. The first blood vessel can include the lateral plantar artery. The second blood vessel can include the lateral plantar vein.

[0065] In some embodiments, a catheter for capturing a guidewire comprises or consists essentially of a sheath and an expandable element. The expandable element has a collapsed state when within the sheath and an expanded state when outside the sheath. The expandable element includes a plurality of cells configured to snare the guidewire.

[0066] The catheter can further include a guide wire sheath that extends through the sheath and the expandable element. The proximal end of the expandable element can be coupled to the guide wire sheath. The expandable element can be configured to expand a blood vessel upon deployment. The expandable element can be visible under fluoroscopy. The expandable element can include struts that define a plurality of cells. The struts can be deflectable when contacted by a needle. The catheter can further include an ultrasonic receiving transducer. The ultrasonic receiving transducer can be distal to the expandable element. The ultrasonic receiving transducer can be longitudinally between the proximal end of the expandable element and the distal end of the expandable element. The ultrasonic receiving transducer can be proximal to the expandable element. A method of capturing a guide wire can include inserting the catheter into a first blood vessel, expanding the expandable element in an expanded state in the first blood vessel, and extending a needle from a second blood vessel through interstitial tissue into the first blood vessel between the proximal end of the expandable element and the distal end of the expandable element. Extending the needle can include extending it through one of the plurality of cells. The method can further include extending the guide wire through the needle into the expandable element and collapsing the expandable element toward a collapsed state. Collapsing the expandable element can include snaring the guide wire.

[0067] In some embodiments, a method of capturing a guide wire includes, consists essentially of, or consists of expanding the expandable element in an expanded state within a first blood vessel and extending a needle from a second blood vessel through interstitial tissue into the first blood vessel between the proximal end of the expandable element and the distal end of the expandable element. The expandable element includes a plurality of cells. Extending the needle includes extending it through one of the plurality of cells. The method further includes extending the guide wire through the needle into the expandable element and collapsing the expandable element toward a collapsed state. Collapsing the expandable element includes snaring the guide wire.

[0068] Crushing the expandable element can include twisting the expandable element. Expanding the expandable element can include expanding the first blood vessel. Extending the needle can include targeting the expandable element under fluoroscopy. This method can further include retracting the expandable element proximally. Retracting the expandable element proximally can include routing a guidewire through the first blood vessel.

[0069] In some embodiments, the device for deploying the tubular structure comprises, or consists essentially of, a handle body, a knob, and a slider. The handle body includes a first segment including threads, a second segment proximally longitudinally adjacent to the first segment, and a longitudinal slot. The second segment has no threads. The knob includes threads. The knob is at the distal end of the first segment in the starting position. The slider is operably connected to the knob. The slider is coupled to the sheath. The knob is configured to rotate proximally around the handle body of the first segment and to slide proximally along the handle body of the second segment. The slider is configured to retract the sheath proximally by a first amount while rotating the knob and to retract the sheath proximally by a second amount while sliding the knob. The device is configured to fully deploy the tubular structure after the sheath has been retracted by the second amount.

[0070] The first amount can be less than the second amount. The first amount can be 10% - 50% of the second amount. The tubular structure can include a stent. The tubular structure can include a stent graft.

[0071] In some embodiments, the method of deploying a tubular structure comprises, or consists essentially of, rotating a knob about a handle body. Rotating the knob about the handle body includes retracting the sheath proximally and deploying a first amount of the tubular structure. The method further includes sliding the knob proximally along the handle body after rotating the knob about the handle body. Sliding the knob proximally along the handle body includes retracting the sheath proximally that deploys a second amount of the tubular structure. The first amount and the second amount are the total amount of the tubular structure.

[0072] The first amount can be less than the second amount. The first amount can be 10% to 50% of the second amount. The tubular structure can include a stent. The tubular structure can include a stent graft.

[0073] In some embodiments, an apparatus for deploying a tubular structure comprises, or consists essentially of, a sheath, a handle body, a knob including a worm gear having teeth, and a slider coupled to the sheath. The slider includes a first portion within the handle body, a second portion outside the handle body, and a worm screw having teeth configured to interact with the teeth of the worm gear. The slider is configured to retract the sheath proximally by a first amount while rotating the knob, and is configured to retract the sheath proximally by a second amount while sliding the slider. The apparatus is configured to fully deploy the tubular structure after the sheath has been retracted by the second amount.

[0074] The first amount can be less than the second amount. The first amount can be 10% to 50% of the second amount. The tubular structure can include a stent. The tubular structure can include a stent graft. The handle body can include a longitudinal slot. The slider can include a third portion extending through the longitudinal slot. The handle body can include a second longitudinal slot. The slider can include a fourth portion outside the handle body and a fifth portion extending through the second longitudinal slot. The fourth portion can be on the opposite side of the handle body from the second portion. The handle body can include a shell that at least partially covers the second portion of the slider until the sheath can be retracted proximally by the first amount.

[0075] In some embodiments, the method of deploying the tubular structure includes, or consists essentially of, rotating the knob. Rotating the knob includes retracting the sheath proximally and deploying a first amount of the tubular structure. The method further includes sliding the slider proximally along the handle body after rotating the knob. Sliding the slider proximally along the handle body includes retracting the sheath proximally by a second distance and deploying a second amount of the tubular structure. The first amount and the second amount are the total amount of the tubular structure.

[0076] The first amount can be less than the second amount. The first amount can be 10% to 50% of the second amount. The tubular structure can include a stent. The tubular structure can include a stent graft. The knob can include a worm gear including teeth. The slider can include a worm screw including teeth configured to interact with the teeth of the worm gear. The handle body can include a longitudinal slot. The slider can include a first portion within the handle body, a second portion outside the handle body, and a third portion extending through the longitudinal slot. The handle body can include a second longitudinal slot. The slider can include a fourth portion outside the handle body and a fifth portion extending through the second longitudinal slot. The fourth portion can be on the opposite side of the handle body from the second portion. Retracting the slider proximally can include gripping the second portion and the fourth portion. The handle body can include a shell at least partially covering the second portion of the slider until the sheath can be retracted proximally by the first amount. The axis of rotation of the knob can cross the longitudinal axis of the handle body.

[0077] In some embodiments, a method of accessing a subject's tibial vein includes, consists of, or consists essentially of placing a first tourniquet above the knee of the leg, placing a second tourniquet above the ankle of the leg, injecting a quantity of contrast agent from the medial foot vein, and creating a venogram to image the veins of the foot of the leg using fluoroscopy.

[0078] The first tourniquet can be of a different type than the second tourniquet. The first tourniquet can be of the same type as the second tourniquet. The first tourniquet can be of the same size as the second tourniquet. The first tourniquet can be of a different size than the second tourniquet. This method can further include positioning the subject in the reverse Trendelenburg position. This method can further include flattening the subject after injecting a certain amount of contrast agent via the midfoot vein. The contrast agent can include a non-ionic contrast agent. The contrast agent can include a mixture of the contrast agent and saline. The contrast agent can include a 50 / 50 dilution of the contrast agent and saline. The amount of the contrast agent can include between 5 mL and 50 mL. The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. This method can further include palpating the midfoot vein. This method can further include selecting the tibial vein using a venogram. This method can further include advancing a guidewire into the target tibial vein. This method can further include removing the second tourniquet. This method can further include tracking a functional catheter over the guidewire. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The functional catheter can include a snare.

[0079] In some embodiments, a method of accessing the lateral plantar vein of a subject includes placing a first tourniquet above the ankle of the leg, placing a needle in the dorsal medial foot marginal vein towards the toe of the foot of the leg, advancing a first guidewire into the first midfoot vein of the foot, injecting a certain amount of contrast agent, and creating a venogram to image the veins of the foot of the leg using fluoroscopy, or consists essentially of them.

[0080] The contrast agent can include a non-ionic contrast agent. The contrast agent can include a mixture of the contrast agent and physiological saline. The contrast agent can include a 50 / 50 dilution of the contrast agent and physiological saline. The amount of the contrast agent can include between 5 mL and 50 mL. This method can further include selecting two larger lateral plantar veins using a venogram. This method can further include advancing a first guide wire to at least one of the intersections or above the ankle and using ultrasound to examine the veins on the sole of the foot to observe the position of the first guide wire. This method can further include advancing a first guide wire to at least one of the intersections or above the ankle, using ultrasound to examine the veins on the sole of the foot to observe the position of the first guide wire, and accessing the lateral plantar vein including the first guide wire of the foot as distally as possible at the plantar arch of the foot at a second access site. This method can further include advancing a second guide wire into the lateral plantar vein. This method can further include advancing the second guide wire into the posterior tibial vein and to the intersection. This method can further include removing the first guide wire. This method can further include removing the tourniquet. This method can further include tracking a functional catheter over the guide wire. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The functional catheter can include a snare.

[0081] In some embodiments, a method of performing an ascending venography procedure includes, or consists essentially of, injecting a quantity of contrast agent into the venous vasculature from a first midfoot vein.

[0082] In some embodiments, a method of performing a descending venography procedure includes, or consists essentially of, injecting a quantity of contrast agent into the venous vasculature from the great saphenous vein toward the foot.

[0083] In some embodiments, a method of aligning a catheter for arteriovenous fistula creation includes inserting a first catheter into a first blood vessel. The first catheter includes a needle opening on a first side of the needle, a radiopaque marker distal to the needle opening and on a second side of the first catheter opposite the first side, and a needle configured to extend through the needle opening. The radiopaque marker is visible under fluoroscopy. The method further includes inserting a second catheter into a second blood vessel. The second catheter includes a balloon. The method further includes expanding the balloon. Expanding the balloon includes inflating the balloon with a radiopaque material visible under fluoroscopy. The method further includes advancing the first catheter longitudinally until the radiopaque marker is proximate to the second catheter within the second blood vessel and aligning the needle opening of the first catheter with the second catheter. Aligning the needle opening includes rotating the first catheter within the first blood vessel such that the radiopaque marker transitions between a first position and a second position. The method further includes monitoring the rotation of the radiopaque marker to the second position to confirm rotational alignment of the needle opening with the second catheter and, after confirming rotational alignment, extending the needle out of the needle opening of the first catheter. Extending the needle includes exiting the first blood vessel, traversing interstitial tissue between the first and second blood vessels, and entering the second blood vessel.

[0084] This method can further include extending a guide wire through a needle into a second blood vessel and entangling the guide wire with a second catheter within the second blood vessel. Entangling the guide wire can include occluding an expandable member of the second catheter. This method can further include, after extending the guide wire, moving the second catheter and detecting a corresponding movement of the guide wire to confirm entanglement of the guide wire in the second catheter. This method can further include moving the second catheter to move the guide wire through the second blood vessel. Moving the second catheter to move the guide wire through the second blood vessel can include exiting the second blood vessel at a location of the foot.

[0085] In some embodiments, a method of aligning a catheter for arteriovenous fistula procedures includes inserting a first catheter into a first blood vessel. The first catheter includes a radiopaque marker and a needle extendable along an extension path. This method further includes inserting a second catheter into a second blood vessel. The second catheter includes an expandable member. The expandable member includes a radiopaque material visible under fluoroscopy. This method further includes expanding the expandable member and aligning the needle of the first catheter with the second catheter. Aligning the needle includes rotating the first catheter within the first blood vessel such that the radiopaque marker transitions between a first position and a second position. This method further includes monitoring rotation of the radiopaque marker to the second position to confirm rotational alignment of the needle extension path and the second catheter, and after confirming rotational alignment, extending the needle along the extension path from the first catheter. Extending the needle includes exiting the first blood vessel, traversing interstitial tissue between the first and second blood vessels, and entering the second blood vessel.

[0086] This method can further include extending a guidewire through the needle into a second blood vessel. Extending the guidewire can include threading the guidewire around an expandable member of a second catheter. This method can further include retracting the expandable member through the second blood vessel. Retracting the expandable member can include advancing the guidewire through the second blood vessel. Threading the guidewire around can include occluding the expandable member of the second catheter. The radiopaque marker can be on a side of the first catheter opposite the needle extension path. The radiopaque marker can be distal to the needle exit opening. The second catheter can include a balloon. The balloon may be inflated with a radiopaque material.

[0087] In some embodiments, a method of aligning a catheter for a venoarterialization procedure includes inserting a first catheter into a first blood vessel. The first catheter includes a radiopaque marker and a needle. The method further includes inserting a second catheter into a second blood vessel. The second catheter includes an expandable member. The method further includes expanding the expandable member. The expanded expandable member includes a radiopaque material. The method further includes aligning the needle extension path with the second blood vessel using the radiopaque marker and the radiopaque material and extending the needle from the first blood vessel through interstitial tissue between the first and second blood vessels into the second blood vessel.

[0088] This method can further include extending a guide wire through a needle into a second blood vessel and threading the guide wire onto a second catheter. Threading the guide wire can include occluding an expandable member. This method can further include moving the second catheter to move the guide wire through the second blood vessel. Aligning the needle's extension path with the second blood vessel can include rotating a first catheter within a first blood vessel such that a radiopaque marker transitions between a first position and a second position. The first position can include a first thickness visible under fluoroscopy. The second position can include a second thickness visible under fluoroscopy. The first thickness can be different from the second thickness. The first catheter can include a needle opening on a first side. The radiopaque marker can be on a second side of the first catheter opposite the first side. The first catheter can include the needle opening proximal to the radiopaque marker. The expandable member can include a balloon. Expanding the expandable member can include inflating the balloon with a radiopaque material.

[0089] In some embodiments, a method of accessing a subject's tibial vein includes positioning the subject in a reverse Trendelenburg position, placing a first tourniquet above the knee of the leg, placing a second tourniquet above the ankle of the leg, injecting a certain amount of contrast agent via the midfoot vein, flattening the subject after injecting the certain amount of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the tibial vein using the venogram, advancing a guidewire into the selected tibial vein, removing the second tourniquet, tracking a functional catheter over the guidewire, snaring a second guidewire extending from an artery using the functional catheter, retracting the second guidewire from the foot, and tracking a second functional catheter over the second guidewire. The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotome. The valve inactivation device can include a cutting balloon. The valve inactivation device can include an atherectomy device.

[0090] In some embodiments, a method of accessing a subject's tibial vein includes injecting a certain amount of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the tibial vein using the venogram, advancing a guidewire into the selected tibial vein, tracking a functional catheter over the guidewire, extending a second guidewire from an artery to the tibial vein, snaring the second guidewire using the functional catheter, retracting the second guidewire from the foot, and tracking a second functional catheter over the second guidewire.

[0091] The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotome. The valve inactivation device can include a cutting balloon. The valve inactivation device can include an atherectomy device.

[0092] In some embodiments, a method of accessing a subject's tibial vein includes injecting a certain amount of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the tibial vein using the venogram, advancing a guidewire into the selected tibial vein, and tracking a functional catheter over the guidewire.

[0093] The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. The functional catheter can include an element configured to snare a guidewire. The method can further include snaring a second guidewire extending from an artery using the functional catheter and retracting the second guidewire. The method can further include tracking a second functional catheter over the second guidewire. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotome. The valve inactivation device can include a cutting balloon. The valve inactivation device can include an atherectomy device.

[0094] In some embodiments, the cutting snare system includes or consists essentially of a snare structure and a valvulotome structure.

[0095] The system can further include an outer sheath. The snare structure and the valvulotome structure can be made interchangeable within the outer sheath. The valvulotome structure can be proximal to the snare structure. The snare structure can be configured to extend from the distal end of the outer sheath. The valvulotome structure can be monolithic with the snare structure. The outer sheath can include a plurality of openings. The valvulotome structure can be configured to extend laterally through the plurality of openings from the outer sheath. The snare structure can include a plurality of cells configured to receive a guide wire. The snare structure can include a plurality of struts configured to snare the guide wire. The snare structure can include a plurality of wires configured to snare the guide wire. The valvulotome structure can be proximal to the snare structure. The valvulotome structure can be distal to the snare structure. The valvulotome structure can be monolithic with the snare structure. The snare structure can have a first diameter, and the valvulotome structure can have a second diameter smaller than the first diameter. The snare structure can be configured to invert to the valvulotome structure when a longitudinal force is applied to the snare structure. The valvulotome structure can be separable from the snare structure. The valvulotome structure can be configured to fit into the snare structure. The snare structure can be configured to fit into the valvulotome structure. The valvulotome structure can include an expandable member configured to apply a radially outward force to the snare structure. The valvulotome structure can include a plurality of blades. The plurality of blades can include between two and eight blades. The plurality of blades can include three blades. The plurality of blades can include four blades. The plurality of blades can face proximally. The plurality of blades can face distally. The plurality of blades can face both proximally and distally.

[0096] In some embodiments, the cutting snare system includes or consists essentially of a snare structure including a plurality of cells configured to receive a guide wire, a valvulotomy knife structure including between two proximally facing blades and eight proximally facing blades, and an outer sheath. The snare structure and the valvulotomy knife structure are expandable from the outer sheath. The valvulotomy knife structure can be monolithic with the snare structure.

[0097] In some embodiments, a method of accessing a target plantar vein of a subject includes positioning the subject in a reverse Trendelenburg position, placing a first tourniquet above the knee of the leg, placing a second tourniquet above the ankle of the leg, injecting a quantity of contrast agent via the midfoot vein, flattening the subject after injecting the quantity of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the plantar vein using the venogram, advancing a guide wire into the selected plantar vein, removing the second tourniquet, tracking a functional catheter over the guide wire, snaring a second guide wire extending from an artery using the functional catheter, retracting the second guide wire from the foot, and tracking a second functional catheter over the second guide wire.

[0098] The midfoot vein can be a dorsal midfoot vein. The midfoot vein can be a plantar midfoot vein. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotomy knife. The valve inactivation device can include a cut balloon. The valve inactivation device can include an atherectomy device.

[0099] In some embodiments, a method of accessing a target plantar vein includes injecting a certain amount of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the plantar vein using the venogram, advancing a guide wire into the selected plantar vein, tracking a functional catheter over the guide wire, extending a second guide wire from the artery to the plantar vein, snaring the second guide wire using the functional catheter, retracting the second guide wire from the foot, and tracking a second functional catheter over the second guide wire.

[0100] The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotome. The valve inactivation device can include a cutting balloon. The valve inactivation device can include an atherectomy device.

[0101] In some embodiments, a method of accessing a target plantar vein includes injecting a certain amount of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the plantar vein using the venogram, advancing a guide wire into the selected plantar vein, tracking a functional catheter over the guide wire.

[0102] The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. The functional catheter can include an element configured to snare a guidewire. The method can further include snaring a second guidewire extending from an artery using the functional catheter and retracting the second guidewire. The method can further include tracking a second functional catheter over the second guidewire. The functional catheter can include a catheter for forming a fistula (e.g., a target catheter, a firing catheter). The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotome. The valve inactivation device can include a cutting balloon. The valve inactivation device can include an atherectomy device.

[0103] In some embodiments, a method of accessing a subject's plantar vein includes positioning the subject in a reverse Trendelenburg position, placing a first tourniquet above the knee of the leg, placing a second tourniquet above the ankle of the leg, injecting a quantity of contrast agent via the midfoot vein, flattening the subject after injecting the quantity of contrast agent via the midfoot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting a plantar vein using the venogram, advancing a guidewire into the selected plantar vein, removing the second tourniquet, tracking a functional catheter over the guidewire, snaring a second guidewire extending from a vein using the functional catheter, retracting the second guidewire from the foot, and tracking a second functional catheter over the second guidewire.

[0104] The midfoot vein can be the dorsal midfoot vein. The midfoot vein can be the plantar midfoot vein. The functional catheter can include a catheter for forming a fistula. The second functional catheter can include a valve inactivation device. The valve inactivation device can include a valvulotome.

[0105] In some embodiments, a method of accessing a target tibial vein includes placing a first tourniquet above the knee of the leg, placing a second tourniquet above the ankle of the leg, injecting a certain amount of contrast agent via the medial foot vein, creating a venogram to image the veins of the foot of the leg using fluoroscopy, selecting the tibial vein using the venogram, advancing a guide wire into the selected tibial vein, removing the second tourniquet, and tracking a functional catheter over the guide wire. The first tourniquet can be of a different type than the second tourniquet.

[0106] In some embodiments, a method of aligning a catheter includes placing a first catheter in a first blood vessel and placing a catheter in a second blood vessel. The first catheter includes a radiopaque material. The catheter includes a flat rectangular radiopaque marker. The method further includes rotating an imaging system until the first catheter and the catheter are within an imaging plane. Rotating the imaging system includes drawing a first centerline on the first catheter, drawing a second centerline on the catheter, maximizing the distance between the first centerline and the second centerline, and creating a signal that the first catheter and the catheter are within the imaging plane. The method further includes rotating the catheter until the thickness of the flat rectangular radiopaque marker is minimized. Rotating the catheter includes drawing a first line along a first long edge of the flat rectangular radiopaque marker, drawing a second line along a second long edge of the flat rectangular radiopaque marker opposite the first long edge, minimizing the distance between the first long line and the second line, and creating a signal that the thickness is minimized. The method further includes extending a needle in the imaging plane out of the second blood vessel and into the first blood vessel from the catheter within the second blood vessel.

[0107] In some embodiments, a method of aligning a catheter includes disposing a first catheter in a first blood vessel and disposing a second catheter in a second blood vessel. The first catheter includes a radiopaque material. The catheter includes a radiopaque marker. The method further includes rotating an imaging system until the first catheter and the second catheter enter an imaging plane and rotating the catheter until the thickness of the radiopaque marker is minimized. Rotating the catheter includes creating a signal that the thickness is minimized.

[0108] In some embodiments, a method of aligning a catheter includes disposing a catheter including a radiopaque marker within a blood vessel and rotating the catheter until the thickness of the radiopaque marker is minimized. Rotating the catheter can include creating a signal that the thickness is minimized.

[0109] In some embodiments, a method of aligning a first blood vessel and a second blood vessel with an imaging plane includes disposing a first catheter in the first blood vessel and disposing a second catheter in the second blood vessel. The first catheter includes a radiopaque material. The second catheter includes a radiopaque marker. The method further includes rotating the imaging system until the first catheter and the second catheter enter the imaging plane. Rotating the imaging system includes drawing a first centerline on the first catheter, drawing a second centerline on the second catheter, maximizing the distance between the first centerline and the second centerline, and creating a signal that the first catheter and the second catheter are within the imaging plane.

[0110] In some embodiments, a method of aligning a catheter includes injecting a contrast agent into a first blood vessel, injecting a contrast agent into a second blood vessel, and rotating an imaging system until the first and second blood vessels enter an imaging plane. Rotating the imaging system includes drawing a first line along the first blood vessel, drawing a second line along the second blood vessel, maximizing the area between the first line and the second line, and creating a signal that the first and second blood vessels are within the imaging plane. The method further includes placing the catheter in the second blood vessel. The catheter includes a flat rectangular radiopaque marker. The method further includes rotating the catheter until the thickness of the flat rectangular radiopaque marker is minimized. Rotating the second catheter includes drawing a first line along a first long edge of the flat rectangular radiopaque marker, drawing a second line along a second long edge of the flat rectangular radiopaque marker opposite the first long edge, minimizing the distance between the first long line and the second line, and creating a signal that the thickness is minimized. The method further includes extending a needle in the imaging plane out of the second blood vessel and into the first blood vessel from the catheter within the second blood vessel.

[0111] In some embodiments, a method of aligning a catheter includes injecting a contrast agent into a first blood vessel, injecting a contrast agent into a second blood vessel, and rotating an imaging system until the first and second blood vessels enter an imaging plane. Rotating the imaging system includes drawing a first line along the first blood vessel, drawing a second line along the second blood vessel, maximizing the area or distance between the first line and the second line, and creating a signal that the first and second blood vessels are within the imaging plane. The method further includes placing the catheter in the second blood vessel.

[0112] In some embodiments, a method of aligning a first blood vessel and a second blood vessel to an imaging plane includes injecting a contrast agent into the first blood vessel, injecting a contrast agent into the second blood vessel, and rotating an imaging system until the first blood vessel and the second blood vessel are within the imaging plane.

[0113] In some embodiments, a method of aligning a catheter includes disposing a first catheter in a first blood vessel and disposing the catheter in a second blood vessel. The catheter includes a radiopaque marker. The method further includes rotating the catheter until the thickness of the radiopaque marker is minimized and creating a signal that the thickness is minimized.

[0114] In some embodiments, a method of aligning a catheter includes disposing a first catheter in a first blood vessel and disposing the catheter in a second blood vessel. The catheter includes a radiopaque marker. The method further includes rotating the catheter until the thickness of the radiopaque marker is less than a value and creating a signal that the thickness is less than the value. The value can be less than 3 mm. The value can be less than 1 mm. The value can be less than 10 μm.

[0115] In some embodiments, a method of increasing blood perfusion to a distal portion of a limb via retrograde flow through the venous system includes diverting blood from an artery to a first vein and establishing a blood flow loop between the first vein and a second vein.

[0116] The distal portion of the limb may include a foot. The distal portion of the limb may include a hand. The distal portion of the limb may include a toe. The distal portion of the limb may include a finger. The artery may be a posterior tibial artery. The first vein may be a medial plantar vein. The second vein may be an anterior tibial vein. The second vein may be a lateral plantar vein. The first vein may be on a first side of the dorsal venous arch of the foot, and the second vein may be on a second side of the dorsal venous arch of the foot.

[0117] Establishing a blood flow loop may include disabling at least one valve of the first vein or the second vein. Disabling at least one valve of the first vein or the second vein may include using a valvulotome. Disabling at least one valve of the first vein or the second vein may include using a balloon. Disabling at least one valve of the first vein or the second vein may include using a stent. The stent can inhibit perfusion into the branched blood vessels through the side wall.

[0118] The method may include establishing a second blood flow loop between either the first vein or the second vein and the third vein. The third vein may be the lateral plantar vein. Establishing the second blood flow loop may include disabling the valve within the third vein. Disabling the valve of the third vein may include using a valvulotome. Disabling the valve of the third vein may include using a balloon. Disabling the valve within the third vein may include using a stent. The stent can inhibit perfusion into the branched blood vessels through the side wall. Establishing the second blood flow loop may be during the same intervention procedure. Establishing the second blood flow loop may be during a subsequent intervention procedure.

[0119] The method may further include restricting outflow within the venous system. Restricting outflow of the venous system may include diverting blood through a bifurcated vein or a collateral branch.

[0120] The method may further include embolizing the bifurcated vein or the collateral branch. Embolizing the bifurcated vein or the collateral branch may include using at least one of a coil, a microsphere, a liquid embolism, or a laser.

[0121] The method may further include applying an external pressure to increase the blood pressure in the distal part of the limb by restricting venous outflow. Applying the external pressure may include using at least one of a cuff, a tourniquet, or a wrap. The application of the pressure may be continuous. The application of the pressure may be intermittent.

[0122] The method may further include redirecting blood from a second artery to at least one of a second vein, a third vein, or a fourth vein. Redirecting blood from an artery to a first vein does not include re-entering the artery. The method may further include forming a fistula between an artery in the distal part of the limb and a vein in the distal part of the limb.

[0123] The method may further include forming a flow loop for a plurality of venous targets. The plurality of venous targets may include at least one vein at a first level in the distal part of the limb and at least one vein at a second level in the distal part of the limb. The plurality of venous targets may include a vein between at least one vein at a first level in the distal part of the limb and at least one vein at a second level in the distal part of the limb. The plurality of venous targets may include perforating branches.

[0124] Establishing a blood flow loop can increase the pressure within the blood flow loop. An increase in the pressure within the blood flow loop can increase the distality of blood perfusion to the limb including the distal part of the limb.

[0125] In some embodiments, a method for increasing blood perfusion to the toes via retrograde flow through the venous system includes redirecting blood from an artery to a first vein. Redirecting blood from an artery to a first vein does not include re-entering the artery. The method further includes establishing a blood flow loop between the first vein and a second vein. The first vein is on a first side of the dorsal venous arch of the foot, and the second vein is on a second side of the dorsal venous arch of the foot. Establishing the blood flow loop includes disabling at least one valve of at least one of the first vein or the second vein using at least one of a valvulotome, a balloon, or a stent. The method further includes restricting venous outflow by directing blood through a bifurcated vein or a collateral. The method further includes embolizing the bifurcated vein or the collateral using at least one of a coil, a microsphere, a liquid embolism, or a laser. The method further includes applying external pressure to increase blood pressure in the distal portion of the limb by restricting venous outflow using at least one of a cuff, a tourniquet, or a wrap.

[0126] In some embodiments, an apparatus, system, kit, etc. for increasing blood perfusion to the toes via retrograde flow through the venous system includes a first prosthesis configured to redirect blood from an artery to a first vein, at least one of a valvulotome, a balloon, or a stent configured to disable a valve to form a blood flow loop between the first vein and a second vein, a shunt stent configured to restrict outflow within the venous system by directing blood through a bifurcated vein or a collateral, at least one of a coil, a microsphere, a liquid embolism, or a laser configured to embolize the bifurcated vein or the collateral, and at least one of a cuff, a tourniquet, or a wrap configured to apply external pressure to increase blood pressure in the foot by restricting venous outflow, or consists essentially of these.

[0127] In some embodiments, an apparatus, system, kit, and method for increasing blood perfusion to the toes via retrograde flow through the venous system are described herein.

[0128] In some embodiments, devices, systems, kits, and methods are described herein for increasing blood perfusion to the distal portion of a limb via retrograde flow through the venous system.

[0129] In some embodiments, a method for increasing blood perfusion to the distal portion of a limb via retrograde flow through the venous system includes establishing a blood flow loop between a first vein and a second vein.

[0130] In some embodiments, a device for redirecting blood flow from a first blood vessel to a second blood vessel and maintaining blood flow within the first blood vessel comprises or consists essentially of a first segment and a second segment. The first segment is configured to be secured within the first blood vessel. The first segment comprises a window that permits blood to flow into the first segment and distally of the first blood vessel through the window. The second segment is configured to be secured within the second blood vessel. The second segment is configured to permit blood to flow into the first segment and into the second blood vessel through the second segment.

[0131] The first segment may comprise a stent structure. At least a part of the stent structure may not be covered. The second segment may comprise a stent structure. At least one parameter of the stent structure may be different between the first segment and the second segment. The parameter may include a cell pattern. The second segment may include a graft coating. The graft coating may be substantially perpendicular to the longitudinal axis of the device. The graft coating may be at an angle with respect to the longitudinal axis of the device. The angle may be from about 10° to about 70°. The first segment may include a graft coating. The graft coating of the first segment may include a V-shaped notch. The first segment may be deployable separately from the second segment. The window may be formed during the manufacturing process. The window may be formed in situ. The first segment may comprise a pierceable graft. The first segment may comprise a stent structure configured to facilitate piercing. The first segment may comprise a flap configured to open radially outward. The first segment may comprise a plurality of flaps configured to open radially outward. The first segment may comprise a branch configured to be disposed within a branch vessel of the first vessel. The first segment may comprise a plurality of slits configured to open upon flexion of the first segment. The device may comprise a knitted or woven fabric having a variable porosity along its length. The first segment may comprise a portion having a first porosity configured to allow perfusion of blood through the portion. The second segment may comprise a portion having a second porosity configured to divert blood through the portion. The first porosity may be less than 75%. The second porosity may be greater than 60%. The device may further comprise an occlusive implant. The occlusive implant may comprise a tether configured to be fixed within the second segment. The second segment may comprise a third segment configured to restrict fluid flow through the device. The third segment may include a diameter smaller than that of the second segment. The first segment may comprise a flange.

[0132] In some embodiments, a method of forming a window in a device for redirecting blood flow from a first blood vessel to a second blood vessel and maintaining blood flow within the first blood vessel includes, or consists essentially of, implanting the device within the first blood vessel, extending through interstitial tissue into the second blood vessel, and inserting a guide wire through a bend of the device within the first blood vessel. The guide wire pierces through the graft material to form an opening.

[0133] The method may further include tracking a dilator over the guide wire to expand the opening. The dilator may have a curved tip. Inserting the guide wire through the bend may include exiting a catheter having an angled ramp. The catheter may further comprise a straight path. The method may further include tracking a balloon over the guide wire. The balloon may extend through the opening. The method may further include expanding the balloon. The expanded balloon can enlarge the opening. The method may further include securing the guide wire. Securing the guide wire may include expanding a fixation balloon within the first blood vessel. Inserting the guide wire through the bend may include forming multiple openings. The method may further include placing a radiopaque target outside the device and downstream of the device within the first blood vessel. The method may further include deploying a stent through the opening.

[0134] In some embodiments, a device for redirecting blood flow from a first blood vessel to a second blood vessel and maintaining blood flow within the first blood vessel comprises, or alternatively consists essentially of, a first section comprising a stent structure including pores configured to allow blood to flow into a first compartment, through the pores, distally within the first blood vessel, and / or into the first compartment, through the first compartment, distally within the first blood vessel, and a second section configured to allow blood to flow from the first blood vessel into a second compartment, through the second compartment, and into the second blood vessel.

[0135] The proximal end of the first section may be configured to be disposed within the first blood vessel. The distal end of the first section may be configured to be disposed within the second blood vessel. The proximal end of the first section may be configured to be disposed within the first blood vessel. The distal end of the first section may be configured to be disposed within the first blood vessel. The proximal end of the second section may be configured to be disposed within the first blood vessel. The distal end of the second section may be configured to be disposed within the second blood vessel. The length of the first section may be approximately the same as the length of the second section. The length of the first section may be different from the length of the second section. The diameter of the first section may be approximately the same as the diameter of the second section. The diameter of the first section may be different from the diameter of the second section. The second section may taper from the proximal end to the distal end. The proximal section of the first section may have a crescent shape. The distal section of the first section may have a circular shape. The proximal end of the first section may be configured to be fixed within the first blood vessel and may taper inwardly towards the distal end. The second section may extend from the distal end of the first section. The second segment may comprise a third segment configured to restrict the flow of fluid through the device. The third segment may include a diameter narrower than the second segment. The first segment may comprise a flange.

[0136] In some embodiments, the implant comprises, or alternatively consists essentially of, a first portion comprising an occlusive implant configured to occlude blood flow within a blood vessel, and a second portion connected to the first portion. The second portion comprises an anchor configured to be coupled to a stent.

[0137] The occlusive implant can include at least one of an expandable mesh, sponge, plug, coil, plurality of coils, embolization liquid, hydrogel, microsphere, or implantable balloon. The anchor may comprise a wire configured to form a coil upon release from a catheter.

[0138] In some embodiments, an apparatus for redirecting blood flow from a first blood vessel to a second blood vessel and maintaining blood flow within the first blood vessel comprises, or consists essentially of, a flare fixed to the first blood vessel and an elongate section extending from the flare. The elongate section is configured to be fixed within the second blood vessel.

[0139] The flare may be configured to extend minimally within the first blood vessel. The apparatus may comprise a plurality of flares including the flare. The flares of the plurality of flares may be symmetric. The flares of the plurality of flares may be asymmetric. At least one flare of the plurality of flares may be longer than other flares of the plurality of flares. At least one flare may be configured to be downstream of other flares within the first blood vessel. The flare may be coated. The flare may not be coated. The elongate section may comprise a third segment configured to restrict fluid flow through the apparatus. The third segment may include a smaller diameter than a second segment.

[0140] In some embodiments, an apparatus for redirecting flow from a branched blood vessel and perfusing a distal blood vessel comprises, or consists essentially of, a plurality of wires integrally woven to form a mesh structure. The mesh structure may have an expanded diameter of about 4 mm to about 8 mm. The mesh structure may have a porosity of about 60% to about 75%. The mesh structure may have a length of about 50 mm to about 150 mm. The expanded structure may have a braiding angle of about 120° to about 179°. The mesh structure may have a compression resistance of about 0.4 N / mm to about 1.1 N / mm.

[0141] The mesh structure may have a frustum of a cone shape. The mesh structure may taper from an expanded diameter to a second expanded diameter. The second expanded diameter may be configured to be downstream of the expanded diameter. The mesh structure may have a chronic outward force of about 0.25 N / mm to about 0.6 N / mm. Each of the plurality of wires may have a diameter of about 50 μm to about 100 μm. Each of the plurality of wires may include a shape memory material. The mesh structure may have a PPI of about 50 to about 150.

[0142] In some embodiments, an apparatus for reducing turbulent flow within a blood vessel comprises, or alternatively consists essentially of, a first segment configured to overlap a stent graft having a first diameter and capable of expanding the blood vessel, and a second segment tapering from the first diameter toward a second diameter. The apparatus is configured to expand the blood vessel in a tapered manner to provide laminar flow through the apparatus.

[0143] The diameter may be about 2 mm to about 10 mm. The second diameter may be about 1 mm to about 8 mm. The second segment may have a length of about 5 mm to about 100 mm. The second segment may have a porosity of about 60% to about 75%. The apparatus may further comprise a first radiopaque marker at the proximal end of the first segment. The apparatus may further comprise a second radiopaque marker at the transition between the first segment and the second segment.

[0144] In some embodiments, an apparatus for restricting the flow of fluid through the apparatus comprises, or alternatively consists essentially of, a first segment having a first diameter and configured to be secured to a first blood vessel, a second segment having a second diameter and configured to be secured to a second blood vessel, a third segment, a fourth segment, and a fifth segment. The third segment has a third diameter that is smaller than the first diameter and the second diameter. The third diameter is configured to restrict the flow of fluid through the apparatus. The second segment tapers from the first diameter towards the third diameter. The fourth segment tapers from the third diameter towards the second diameter.

[0145] The first segment may be configured to divert the fluid flow from the first blood vessel to the second blood vessel. The first segment may be configured to allow the fluid to continue flowing through the first blood vessel. The first segment may include a window. The first diameter may be smaller than the second diameter. The first diameter may be the same as the second diameter. The first segment may include a flange having a fourth diameter larger than the first diameter. The device may include a stent structure and a graft. At least a portion of the first segment may be lacking a graft. The graft may have a third diameter in the third segment. The stent structure may have a fourth diameter larger than the third diameter in the third segment. The graft in the third segment may be configured to bend inward in response to a change in pressure. The graft in the third segment may be configured to bend outward in response to a change in pressure. The first segment may be configured to be fixed within the P3 segment of the popliteal artery. The first segment may be configured to be fixed to the tibiofibular trunk. The first diameter may be about 5 mm to about 7 mm. The first diameter may be about 4 mm to about 6 mm. The second diameter may be about 5 mm to about 7 mm. The third diameter may be about 2.5 mm to about 5 mm. At least one of the second segment or the third segment may be configured to provide laminar flow to the fifth segment.

[0146] In some embodiments, a device for restricting fluid flow through the device comprises, or alternatively consists essentially of, a first segment having a first diameter and configured to be fixed to a first blood vessel, a second segment having a second diameter and configured to be fixed to a second blood vessel, and a third segment. The first diameter is configured to restrict the fluid flow through the device. The second segment tapers from the first diameter towards the second diameter.

[0147] The first segment may be configured to divert the fluid flow from the first blood vessel to the second blood vessel. The first segment may be configured to allow the fluid to continue to flow through the first blood vessel. The first segment may include a window. The first segment may include a flange having a third diameter that is larger than the first diameter. The device may include a stent structure and a graft. At least a portion of the first segment may be lacking a graft. The graft may have a first diameter in the first segment. The stent structure may have a third diameter that is larger than the first diameter in the first segment. The graft in the first segment may be configured to bend inwardly in response to a change in pressure. The graft in the first segment may be configured to bend outwardly in response to a change in pressure. The first diameter may be from about 2.5 mm to about 5 mm. The second diameter may be from about 5 mm to about 7 mm.

[0148] In some embodiments, a device for restricting fluid flow through the device includes, or alternatively consists essentially of, a first segment having a first diameter and configured to be secured to the first blood vessel, a second segment extending across the first segment, a third segment having a second diameter and configured to be secured to the second blood vessel, and a fourth segment. The second segment has a third diameter that is smaller than the first diameter and the second diameter. The third diameter is configured to restrict fluid flow through the device. The third segment tapers from the third diameter toward the second diameter.

[0149] The first segment may be configured to divert the fluid flow from the first blood vessel to the second blood vessel. The first segment may be configured to allow the fluid to continue to flow through the first blood vessel.

[0150] In some embodiments, an implant for restricting the flow of fluid through a lumen comprises, or consists essentially of, a first segment, a second segment, and a third segment. The second segment has a first diameter configured to restrict the flow of fluid through the implant and to restrict the flow of fluid through the lumen when the implant is disposed within the lumen. The first segment tapers from a second diameter configured to secure the implant within the lumen to the first diameter. The second segment tapers from the first diameter configured to secure the implant within the lumen to a third diameter.

[0151] The first diameter may be from about 2.5 mm to about 5 mm. The graft in the first segment may be configured to bend inwardly in response to a change in pressure. The graft in the first segment may be configured to bend outwardly in response to a change in pressure. The lumen may be a shunt device. The lumen may be a vein. The system can comprise the implant and a shunt device configured to divert the flow of fluid from a first blood vessel to a second blood vessel. The implant may be configured to be disposed within the shunt device. The implant may be configured to be disposed within the second blood vessel.

[0152] The methods outlined above and described in further detail below describe some of the steps taken by a general practitioner, but it will be understood that they can also include instructions for those steps to be taken by others. Thus, a step such as "rendering the valve in the first blood vessel non-functional" includes "instructing that the valve in the first blood vessel be rendered non-functional".

[0153] For the purpose of summarizing the present invention and the advantages that can be achieved, some objectives and advantages are described herein. Not all such objectives or advantages necessarily need to be achieved in accordance with any particular embodiment. In some embodiments, the present invention can be embodied or performed in a manner that achieves or optimizes one advantage or group of advantages without necessarily achieving other objectives or advantages.

[0154] All of these embodiments are intended to be within the scope of the present invention as disclosed herein. These and other embodiments will become apparent from the following detailed description with reference to the accompanying drawings, without limiting the present invention to any particular disclosed embodiment(s). Any features and / or preferred features described with reference to some embodiments can be incorporated into other embodiments in combination with other embodiments. All documents mentioned herein, including patents and patent applications, are hereby incorporated by reference in their entirety to form a part of this specification.

Brief Description of the Drawings

[0155] These features, aspects, and advantages of the present disclosure, as well as other features, aspects, and advantages, are described with reference to the drawings of some embodiments, which are intended to illustrate some embodiments but not to limit the present invention, and like reference numerals are used for like features in those drawings.

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DETAILED DESCRIPTION OF THE INVENTION

[0315] Some embodiments and examples will be described below, but the present invention extends beyond the specifically disclosed embodiments and / or their uses and obvious modifications and their equivalents. The scope of the present invention as disclosed herein is not to be limited by any particular embodiment (s) described below.

[0316] Minimally invasive surgery can provide means for treating a wider range of patients, including means currently excluded from standard surgical methods. One such procedure is percutaneous in situ coronary venous arterialization (PICVA), which is a catheter-based coronary bypass procedure in which an occlusion in an affected artery is "bypassed" by creating a channel between a coronary artery and an adjacent coronary vein. In this way, arterial blood can be diverted into the venous system and the heart tissue can be perfused in a retrograde manner (retrograde perfusion), returning the blood supply to the ischemic tissue. Some exemplary devices and methods for performing procedures such as PICVA are described in PCT International Publication No. 99 / 049793 and US Patent Application Publication No. 2004 / 0133225, and the above PCT application and US patent application are hereby incorporated by reference in their entirety as part of this specification.

[0317] Previously, successfully performing a minimally invasive procedure to divert blood flow from an artery to an adjacent vein has often had a low success rate due to the inability to properly target the vein from the artery. Without an appropriate system and method, such procedures (e.g., attempts to target a vein by a combination of X-ray fluoroscopy and an imaging ultrasound probe positioned at the distal tip of a catheter as described, for example, in U.S. Patent Application Publication No. 2004 / 0133225) often tend to fail even before they are started. In fact, such a configuration can be difficult to operate, and the location of the adjacent vein being restricted may require a significant amount of skill on the part of the clinician. Improvements in targeting systems and methods, such as the systems and methods using the catheter described herein, can generally enable procedures such as PICVA and transvascular surgery. Without such improvements, such percutaneous methods would remain unimportant compared to conventional open-heart surgery and other types of bypass surgery.

[0318] This application describes methods and systems useful in minimally invasive surgery that, according to some embodiments, can reduce the work of conventional surgery in treating conditions such as coronary heart disease and critical limb ischemia. For example, in another situation, it can treat patients who would otherwise be unable to undergo surgery such as coronary artery bypass surgery or peripheral artery disease bypass surgery, and can reduce or significantly reduce the degree of surgical trauma, the risk of infection, and / or the recovery time compared to conventional surgery.

[0319] FIG. 1 schematically shows an exemplary embodiment of an emitting device 10 that guides a signal from a first body cavity 30 to a target device 20 within a second body cavity 35. The emitting device 10 includes a signal transmitter 21. The emitting device 10 can include, for example, a catheter having an elongated flexible rod-shaped portion and a tip portion, and can provide a conduit for performing treatment within a patient's body. The emitting device 10 can be suitable for positioning and movement through a first body cavity within a patient's body, i.e., a blood vessel 30 (e.g., a heart cavity, coronary artery, coronary vein, peripheral artery, peripheral vein). The elongated portion of the emitting device 10 has an outer sheath 11 that defines a lumen 13 and surrounds a space. The space within the lumen 13 can be appropriately divided or subdivided as needed to define a channel for controlling the positioning of the emitting device 10 and the like and for performing treatment. Such subdivision can be achieved, for example, longitudinally and concentrically in the axial direction.

[0320] The emitting device 10 includes a signal transducer 12. The signal transducer 12 is configured to supply or emit a signal 40 directed outward from the emitting device 10. In the embodiment shown in FIG. 1, the signal 40 is directed radially outward from the emitting device 10 in a direction perpendicular to the longitudinal axis of the emitting device 10. As described in more detail below, in some embodiments, the direction of the signal 40 need not be perpendicular to the longitudinal axis of the emitting device 10 and can be directed at an angle with respect to the longitudinal axis of the emitting device 10. Thereby, the signal transducer 12 can form at least a part of the signal generating means.

[0321] The signal transducer 12 is connected to a signal transmitter 50. The signal transmitter 50 can be preferably selected from suitable electromagnetic sources such as ultrasonic waves, or lasers, microwave radiation / irradiation, radio waves, etc. In some embodiments, as described in more detail below, the signal transmitter 50 is configured to generate an ultrasonic signal, and this ultrasonic signal is relayed to the signal transducer 12, and then the signal transducer directs the signal 40 from the first body cavity 30 into the surrounding tissue.

[0322] The target device 20 is positioned within a second adjacent body cavity, namely a blood vessel 32 (e.g., a heart cavity, coronary artery, coronary vein, peripheral artery, peripheral vein) within the patient's body. The first body cavity 30 and the second body cavity 32 are separated by intervening tissue 34, which may be referred to as interstitial tissue or a septum. The first body cavity 30 and the second body cavity 32 are positioned adjacent and parallel to each other over at least a portion of their respective lengths. For example, many of the body's veins and arteries are known to extend parallel to each other over at least a portion of their entire lengths.

[0323] The target device 20 can be considered to have a configuration similar to that of the emitting device 10. For example, the target device 20 can include a catheter having an elongated flexible rod-shaped portion and a tip portion. In another example, minor movement and positioning of the target device 20 within the body cavity 32 can be achieved. In yet another example, the target device 20 can include an outer sheath 21 that defines a lumen 23 and surrounds a space. The lumen 23 can be suitably partitioned, for example, in the same manner as in the case of the emitting device 10.

[0324] The target device 20 includes a receiving transducer 22 configured to receive a signal 40 from the transducer 12 of the emitting device 10. The receiving transducer 22 constitutes at least a part of the signal detecting means. In use, when the receiving transducer 22 receives the signal 40 transmitted from the signal transducer 12, it transmits the received signal to a signal detector 60. The signal detector 60 is configured to provide an output reading to a user of the system, for example, via an output display 61. The output display 61 can be a visual display, an auditory display (e.g., emitting a beep sound or some other sound upon reception of the signal), etc.

[0325] In this way, by transmitting and detecting the directional signal 40, the operation and positioning of the transmitting device 10 with respect to the target device 20 can be enabled. During use, the user of the system can operate the transmitting device 10 and the target device 20 until the output display 61 indicates that the signal 40 is being received by the target device 40.

[0326] In some embodiments, the signal 40 includes or is an ultrasonic signal. The signal 40 is directional and is emitted by the signal transducer 12 in the shape of a narrow cone or arc (for example, the width of the signal band becomes wider as the distance from the signal transducer 12 increases). Therefore, the accuracy of alignment between the transmitting device 10 and the target device 20 depends not only on signal detection but also on the distance between the two devices because the signal beam width becomes wider as the distance increases. This level of error is called "positional uncertainty". There may be a certain tolerance level for positional uncertainty, but when the treatment is to be accurately guided, the degree of uncertainty should be reduced or minimized. For example, when the diameter d of the signal transducer 12 is 1 mm and the frequency of the ultrasonic signal is 30 MHz, the positional uncertainty x (for example, the limit of the error on both sides of the center line) is 1 mm at a vertical separation of 5 mm between the transmitting device 10 and the target device 20. In the case of clinical applications, the positional uncertainty generally should not exceed about ±5 mm (with respect to a total signal beam width of 10 mm at the receiving point). In some embodiments, the positional uncertainty is between about ±0.01 mm and about ±4.50 mm, or between about ±0.1 mm and about ±2 mm. In some embodiments, the positional uncertainty does not exceed about ±1 mm.

[0327] The intensity of signal 40 can be a factor in detection, and generally, the signal intensity decreases as the distance between the emitting device 10 and the target device 20 increases. This distance is partly determined by the amount of intervening tissue 34 between the devices 10, 20. As an example, when signal 40 is an ultrasonic signal, significant signal degradation can be predicted if the emitting device 10 and the target device 20 are separated by a solid tissue (e.g., intervening tissue 34) larger than about 20 mm. The density of the intervening tissue 34 can also potentially affect the degradation of signal 40 as it travels through the distance (e.g., a tissue with a higher density degrades the signal more than a tissue with a lower density).

[0328] The frequency of the ultrasonic signal can also potentially affect the thickness of the signal transducer, and the thickness of the signal transducer is 0.075 mm at 30 MHz in the case of a standard ultrasonic ceramic transducer (e.g., a piezoelectric transducer (PZT)).

[0329] Figure 2 is a cross-sectional view along the dotted line B-B of Figure 1. Since the orientation line 41 can define the location where the treatment is to be performed, the correct orientation of the emitting device with respect to the target device can be a factor in detection. When the directional signal 40 is associated with the treatment delivery means (e.g., parallel and longitudinally offset), the clinical necessity of accurately positioning the treatment on the patient can function better. For example, in this way, the user of the system can perform the treatment at the correct location by ensuring that the emitting device 10 and the target device 20 are correctly positioned by the transmission and reception of signal 40. The orientation line 41 in Figure 2 shows not only the direction but also the path of the signal progression, and the treatment can be performed on the patient along that path.

[0330] Figure 3 schematically shows an exemplary embodiment of the launcher 10. The launcher 10 includes a signal transducer 120 that is angled with respect to the longitudinal axis of the launcher 10. The signal 40 is transmitted at an angle with respect to the direction of travel (e.g., forward travel, transverse travel) of the launcher 10 when the launcher 10 enters the body cavity 30 (FIGS. 1 and 2). In some embodiments, the beam angle is substantially perpendicular to the longitudinal axis of the launcher 10. In some embodiments, the beam angle is between about 20 degrees and about 60 degrees with respect to the perpendicular, between about 30 degrees and about 50 degrees with respect to the perpendicular, or about 45 degrees with respect to the perpendicular, where 0 degrees corresponds to the longitudinal axis of the launcher 10 in the direction of travel.

[0331] The launcher 10 includes a hollow needle or cannula 17, which is an exemplary means for performing treatment. During the advancement of the launcher 10, the hollow needle 17 is located in a non-deployed or contracted state within the lumen 13 of the launcher 10. The hollow needle 17 can be deployed / expanded from the launcher 10 through the hole 16 in the outer sheath 11 when the user deems it appropriate (e.g., when the signal 40 is detected by the target device 20). The hole 16 can enable fluid communication between the lumen 13 and the body cavity 30 (FIG. 1). As shown by the exemplary embodiment of FIG. 3, the hollow needle 17 can travel along a path parallel to the direction of the signal 40. The intervening tissue 34 (FIG. 1) can be punctured using the hollow needle 17. In some embodiments, the hollow needle 17 traverses the entire intervening tissue 34, and when traversing, enables the launcher 10 to access the second body cavity 32 (FIG. 2). If desired, the path created by the hollow needle 17 passing through the intervening tissue 34 can be later widened to enable fluid communication between the first body cavity 30 and the second body cavity 32.

[0332] Treatment means suitable for use in some embodiments can include devices and / or instruments selected from the group consisting of, for example, cannulas, lasers, radiation emitters, probes, drills, blades, wires, needles, suitable combinations thereof, and the like.

[0333] In some embodiments, the hollow needle 17 includes a sensor 19 that can be useful for further determining the position information of the tip of the hollow needle 17 relative to the firing device 10. In some embodiments, the sensor 19 is configured to detect changes in hydrostatic pressure. Other sensors suitable for use in the systems and methods described herein can include temperature sensors, oxygen treatment sensors, and / or color vision sensors.

[0334] Optionally, the hollow needle 17 can include a further signal transducer 122. In the embodiment shown in FIG. 3, the signal transducer 122 is positioned at one end of the guide wire 14 near the tip of the hollow needle 17. The signal transducer 122 can additionally or alternatively be positioned on the hollow needle 17 if desired. In use, the signal transducer 122 is driven by short transmission pulses that generate either a directional or non-directional signal pulse. The signal pulse can be detected by a receiving transducer 22 attached to the target device 20. The distance from the guide wire 14 or the hollow needle 17 to the receiving transducer 22, and thus to the target device 20, can be determined at least in part as a time based on the delay between the transmission of the signal pulse from the signal transducer 122 and the reception of the signal pulse at the receiving transducer 22 side.

[0335] FIG. 4 schematically shows an exemplary embodiment of the target device 20. In the embodiment shown in FIG. 4, the target device 20 is positioned within the body cavity 32. As described above, the target device 20 includes a receiving transducer 22 that receives the signal 40. The receiving transducer 22 can be either unidirectional (e.g., capable of receiving signals from only one direction) or omnidirectional (e.g., capable of receiving signals from any direction). Arrow A indicates the reverse blood flow after arteriovenous angiogenesis (also called PICVA) has occurred. The target device 20 includes an omnidirectional ultrasonic signal receiving transducer 60. An optional reflecting cone 601 can direct the signal 40 onto the disk-shaped receiving transducer 60. An acoustically transparent window 602 can separate the reflecting cone 601 from the receiving transducer 60. In some embodiments, the omnidirectional ultrasonic signal receiving transducer can be obtained by positioning a cylinder of a flexible piezoelectric material such as polyvinylidene fluoride (PVDF) around the outer sheath of the target device 20. In that way, the cylinder can act in a manner similar or equivalent to the receiving transducer 60.

[0336] In the embodiment shown in FIG. 4, the target device 20 has an optional channel 25 for use in administering a drug, such as a therapeutic agent, to the patient. In some embodiments, the channel 25 functions as a conduit that allows the application of a blocking material 251 that serves to at least partially occlude or block the body cavity 32. The blocking material 251 can be appropriately selected from gel-based substances. The blocking material 251 can additionally or alternatively include a plugging member (e.g., a balloon, a self-expanding stent, etc.). The placement of the blocking material 251 can be guided by the movement of the target device 20. The presence of a guide member 24 within the lumen 23 of the target device 20 can enable the user to accurately manipulate the position of the target device 20 as desired.

[0337] Referring again to FIG. 2, the emission device 10 comprises a signal transducer 12, which can optionally be oriented such that the signal 40 is transmitted at an angle other than perpendicular to the signal transducer 12. FIG. 5 schematically shows another exemplary embodiment of the emission device 10. In some embodiments, in the case of the exemplary emission device 10 shown in FIG. 5, the signal transducer is in the form of a single transducer array 123. The signal transducer array 123 includes a plurality of signal transducer elements 124 that can be collectively oriented to at least partially define a signal beam width and an angle with respect to the emission device 10. The smaller size of the elements 124 allows the signal transducer array 123 not to occupy a significant proportion of the lumen 13 of the emission device 10.

[0338] The embodiment shown in FIG. 5 can be useful for ultrasonic beamforming signal transmission. FIG. 5 shows an array of signal transducer elements 124 separately connected to a transmitter 50 via a delay device 51, and the delay device 51 allows the signals for each element 124 to be delayed relative to each other. The delay device can provide or ensure that the ultrasonic waveforms from each element 124 are aligned to generate an ultrasonic beam 40 at a desired angle. In some embodiments, for example where the signal 40 includes visible light, an array of LEDs can be used additionally or alternatively.

[0339] FIG. 6 schematically shows an exemplary embodiment of a centering device for the emission device 10 and / or the target device 20. To assist in the process of aligning the emission device 10 in the first body cavity 30 and the target device 20 in the second body cavity 32, one or both of the devices 10, 20 can have means for centering each device within its respective body cavity.

[0340] In some embodiments, the centering means includes an inflatable bladder or balloon 111 that is positioned within lumens 13, 23 when in the undeployed state and that can expand when devices 10, 20 reach a desired location within the patient's body. The balloon 111 can be disposed on the outer surface of outer sheaths 11, 21. The balloon 111 can be annular in shape so as to at least partially surround devices 10, 20 in a toroidal or doughnut-like fashion. The balloon 111 can be arranged to inflate on only one side of devices 10, 20 or on two opposing sides. As shown in FIG. 6, the balloon 111 is deployed on one side of the delivery device 10.

[0341] In some embodiments, the centering means includes one or more loop structures 112 that are positioned within lumens 13, 23 or within recesses formed within outer sheaths 11, 21 when in the undeployed or contracted state. When devices 10, 20 reach a desired location within the patient's body, the one or more loop structures 112 expand radially outward from devices 10, 20, thereby centering devices 10, 20 within body cavities 30, 32. The outward expansion of the loop structures 112 can be effected, for example, by compressing a length of wire that bows outwardly from outer sheaths 11, 21. A centering device incorporating this configuration can have a plurality of compressible lengths of wire or other suitable flexible material arranged in parallel at radially spaced intervals around the outer periphery of outer sheaths 11, 21. Compression of the plurality of wires can be facilitated by sliding members (not shown) positioned proximally and / or distally near the ends of the plurality of wires. The sliding members are translatable along the longitudinal axis of devices 10, 20. As shown in FIG. 6, the target device 20 includes fully deployed centering means 112 that enables centering of the target device 20 within body cavity 32.

[0342] Other possible means for centering devices 10, 20 within body cavities 30, 32 include, but are not limited to, expandable lantern-type devices, reversibly expandable stents, coils, helices, expandable probes or legs, combinations thereof, and the like.

[0343] In some embodiments, centering means or other means (e.g., balloons, metallic standoffs of various lengths, etc.) can be used to orient devices 10, 20 within body cavities 30, 32 at the center or substantially off-center of the body cavity. For example, device 10 can be oriented proximate to the wall of body cavity 30 through which needle 17 exits the body cavity 30, thereby creating a shorter ultrasonic signal path and / or reducing errors, for example, due to needle 17 traversing the intracavitary space. In another example, device 10 can be oriented proximate to the wall of body cavity 30 that is opposite the wall through which needle 17 exits the body cavity 30, thereby creating a rigid surface against which needle 17 can press, for example. In yet another example, device 20 can be oriented proximate to the wall of body cavity 32 through which needle 17 enters the body cavity 32, thereby providing, for example, a shorter ultrasonic signal path. Other orientations of the device that are neither at the center nor proximal to the center of the blood vessel wall are also possible (e.g., separated from the wall and / or from the center of the lumen by a fraction of the diameter, such as 1 / 2, 1 / 3, 1 / 4, etc.). Example

[0344] The methods and systems described herein demonstrate particular utility in cardiovascular surgery according to some embodiments. Some aspects are further illustrated by the following non-limiting examples, where the system is used by a clinician performing a procedure for connecting an artery and a vein (PICVA) to enable retrograde perfusion of cardiac tissue after coronary artery occlusion.

[0345] The emission catheter 10 is inserted into the occluded coronary artery by standard keyhole surgical methods (e.g., tracking on a guide wire, tracking inside a guide catheter). The target catheter 20 is inserted into a coronary vein that extends parallel to the coronary artery by standard keyhole surgical methods (e.g., tracking on a guide wire, tracking inside a guide catheter). The coronary vein is not occluded and thus effectively enables bypassing the occluded portion in the coronary artery by providing an alternative channel for blood flow to the myocardium.

[0346] The emission catheter 10 includes a PZT ultrasonic transducer 12 (e.g., available from CTS piezoelectric products of Albuquerque, New Mexico), and the PZT ultrasonic transducer 12 is oriented such that the directional ultrasonic beam is transmitted at an angle of 45 degrees (with respect to the longitudinal axis of the emitter) in this example, preferably in the direction of blood flow within the artery 30, although other angles including about 90 degrees are also conceivable. The ultrasonic transducer 12 is activated, and in this example, a 30 MHz directional ultrasonic signal 40 is transmitted from the emission catheter 10, although other frequencies are also conceivable. The target catheter 20 includes an omnidirectional ultrasonic receiving transducer 60. To assist in positioning both the emission catheter 10 and the target catheter 20, both catheters 10, 20 include centering means or orientation means in the form of an annular inflatable balloon 111 in this example, although other centering means or orientation means are also conceivable, or the absence of such means is also conceivable. The centering means 111 on the emission catheter 10 side is deployed by the clinician when the emission catheter 10 is considered to be in an appropriate location near the occluded site within the coronary artery 30. This can be determined by standard fluoroscopic imaging methods and / or physical resistance. The target catheter 20 is then moved into the adjacent coronary vein 32 until the directional ultrasonic signal 40 is detected by the signal receiving transducer 60. To enable more accurate alignment between the emission catheter 10 and the target catheter 20, the centering means 111 on the target catheter 20 side can be deployed before or after the signal 40 is detected.

[0347] When the clinician receives the transmitted signal 40, the clinician can be confident that the ablation catheter 10 and the target catheter 20 are correctly positioned in their respective blood vessels 30, 32 in both the rotational and longitudinal directions, enabling the start of the arterial-to-venous connection procedure. Using the target catheter 20, the blood flow in the coronary vein 32 can be blocked by applying the gel block material 251 through the channel 25 in the target catheter 20. The block material 251 can be applied at a position in the coronary vein 32 that is downstream with respect to the location of the signal receiving transducer 60 with respect to the venous blood flow.

[0348] Next, the clinician can start the arteriovenous connection by deploying the hollow needle 17 from the ablation catheter 10 substantially along a path near and parallel to the path taken by the ultrasonic signal 40 through the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, or the hollow needle 17 can cross a path that obstructs the path of the ultrasonic signal at a point in the coronary vein 32. Optionally, the hollow needle 17 is provided with a sensor 19 near its tip, and the sensor 19 is configured to detect changes in hydrostatic pressure or Doppler flow so that the user can monitor the transition from arterial pressure to venous pressure as the hollow needle 17 passes through the two blood vessels 30, 32. Optionally, the hollow needle 17 is provided with a guide wire 14 in its lumen, i.e., inside the tube, upon deployment. When the hollow needle 17 and the guide wire 14 cross the intervening tissue 34, the hollow needle 17 can retreat back into the lumen 13 of the ablation catheter 10 while leaving the guide wire 14 in place. In some embodiments, when the hollow needle 17 crosses the intervening tissue 34, the user can separately pass the guide wire 14 through the lumen, i.e., the tube, of the hollow needle 17 and retract the needle 17 into the ablation catheter 10.

[0349] The clinician withdraws the delivery catheter 10 from the patient while leaving the guidewire 14 in place. Next, a further catheter device is slid along the guidewire 14. FIG. 7 schematically shows a prosthesis 26, such as an expandable stent 26, in place according to a procedure such as arteriovenous angiogenesis. Further details regarding possible prostheses including stents and stent grafts are shown below. The stent 26 can be deployed to widen a perforation in the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, where the interrupting arrow A indicates the direction of blood flow through the stent 26 between the first body cavity 30 and the second body cavity 32 (e.g., by passing through the stent 26 in this way, it becomes possible for arterial blood to bypass into the venous system and retrogradely perfuse the myocardial tissue). The stent 26 blocks the upstream flow within the body cavity 32 and can push the blood flow within the body cavity 32 in the same direction as the blood flow within the body cavity 30. The graft material of the stent 26 can form a fluid-tight lumen between the body cavity 30 and the body cavity 32. The target catheter 20 is withdrawn from the patient while leaving the blocking material 251 in place. Optionally, as further detailed herein, additional blocks or sutures can be inserted into the coronary vein to prevent or inhibit the backflow of arterial blood.

[0350] While the specific examples described above relate to cardiovascular surgery, the methods and systems described herein can have a wide range of applications in other surgical modalities. For example, any surgery involving the need to direct treatment from one body cavity to another adjacent body cavity (e.g., for the treatment of peripheral arterial disease) can be considered. As such, applications in the fields of neurosurgery, urology, and general vascular surgery can also be contemplated. Depending on the type of treatment, there is no need to limit the formation of a channel between body cavities. For example, the methods and systems described herein can also be used when leading techniques such as catheter ablation, non-contact mapping of the heart cavity, and drug delivery to precise sites of the body.

[0351] Several techniques for effectively bypassing occlusions within arteries by percutaneous surgery have been described above. These techniques involve creating a channel or passageway between a first passageway such as an artery, vein, or cardiac chamber upstream of the occlusion, and a second passageway such as an artery, vein, or cardiac chamber in proximity to the first passageway, and interconnecting the first passageway and the second passageway by a third passageway. Fluids such as blood can be diverted from the first passageway to the second passageway by the third passageway for interconnection. In embodiments where the first passageway includes an artery and the second passageway includes a vein, arterial blood can be perfused retrogradely into the tissue (retrograde perfusion).

[0352] As described above, the interconnecting passageway between the first body cavity passageway and the second body cavity passageway can be created, for example, by deploying a needle outwardly from a first catheter positioned within the first passageway, whereby the needle traverses the interstitial tissue or septum between the first passageway and the second passageway. A second catheter providing a target device for receiving a signal transmitted from the first catheter, such as an ultrasonic signal, can be positioned within the second passageway. By monitoring the received signal, the position of the first catheter relative to the second catheter can be determined to ensure that the needle is deployed in the correct position and orientation to create a passageway for fluid flow between the first passageway and the second passageway.

[0353] To provide or maintain blood flow through the interconnecting passageway or interconnecting channel, a structure having a lumen can be inserted into the passageway to support the interstitial tissue and / or prevent or inhibit the passageway from closing. The tube can include, for example, a stent that is expanded within the channel using a balloon catheter as described herein, or a self-expanding stent. A catheter for delivering the structure, such as a balloon catheter or a self-expanding catheter, can be guided into the channel by a guidewire deployed within the passageway by the first catheter.

[0354] Passages such as arteries, veins, and heart cavities may pulsate when the heart beats due to, for example, the movement of the heart wall, the movement of the peripheral limbs, and / or the fluctuations in pressure within the passage itself. This pulsation may cause the passages to move relative to each other, thereby potentially applying stress to the structures within the interconnecting passages between them. This stress may be greater than the stress experienced by structures within a single passage. The stress may cause premature failure of the structures, for example, due to fatigue failure of stent struts. As a result of the structure failing, the interstitial tissue may be damaged and / or the interconnecting passages may become blocked, which may lead to significant complications or complete failure of the treatment.

[0355] Figure 8 shows an apparatus, i.e., an implant or prosthesis 100, for providing or maintaining fluid flow through at least one passage. The apparatus 100 has a first end portion, i.e., a proximal end portion 102, a second end portion, i.e., a distal end portion 104, and an intermediate portion 106 between the proximal end portion 102 and the distal end portion 104. The apparatus has a lumen, i.e., a lumen 110, through which fluid passes through the apparatus 100. At least an intermediate portion 106 of the apparatus 100, for example, comprises a flexible polymer tube 108. The flexible polymer tube can at least partially define the lumen 110.

[0356] The apparatus 100 has a support structure (e.g., at least one stent) including a mesh 112 and a mesh 114. In some embodiments, at least a portion of the mesh 112 is embedded within the outer wall of the tube 108 in proximity to the proximal end portion 102 of the apparatus 100. In some embodiments, at least a portion of the mesh 114, e.g., wires or struts, is embedded within the outer wall of the tube 108 in proximity to the distal end portion 104 of the apparatus 100. The meshes 112, 114 can include biocompatible metals such as stainless steel and / or shape memory materials such as nitinol or cobalt chromium.

[0357] The wire meshes 112, 114 can respectively reinforce the end portions 102, 104. In some embodiments where the intermediate portion 106 does not include a mesh, the intermediate portion 106 can be relatively flexible compared to the end portions 102, 104, and / or the end portions 102, 104 can have relatively high radial rigidity.

[0358] In some embodiments, the end portions 102, 104 of the device 100 are expandable in the diametrical direction. For example, after formation, i.e., after manufacture, the wire meshes 112, 114 can have a diameter smaller than the passageway, such as a blood vessel, in which the device 100 is deployed. When the device 100 reaches a predetermined position within the passageway, the end portions 102, 104 can be expanded, i.e., deformed outwardly, such that the respective diameters of the end portions 102, 104 increase and abut, for example, against the inner sidewalls of the passageway. The end portions 102, 104 are configured to be maintained indefinitely at the expanded diameter by plastic deformation of the material (e.g., wire, strut) of the meshes 112, 114 and / or by measures of a locking mechanism arranged to mechanically lock the meshes 112, 114 in the expanded position. The intermediate portion 106 of the device 100 can be made expandable in the diametrical direction, for example, by plastic deformation of the tube 108.

[0359] Figure 9 shows the device 100 of FIG. 8 deployed to provide a fluid flow path between the first passageway 116 and the second passageway 118. The passageways 116, 118 can include coronary blood vessels, such as the coronary artery 116 and the coronary vein 118, or conversely the coronary vein 116 and the coronary artery 118. The passageways 116, 118 can include peripheral blood vessels (e.g., blood vessels in the extremities), such as the femoral artery or other peripheral artery 116 and the femoral vein or other peripheral vein 118, or conversely the femoral vein or other peripheral vein 116 and the femoral artery or other peripheral artery 118. The end portions 102, 104 and the intermediate portion 106 of the device 100 expand to merge with and abut against the inner walls of the passageways 116, 118. The distal end portion 104 of the device 100 is positioned within the second passageway 118, and the proximal end portion 102 of the device 100 is positioned within the first passageway 116. The intermediate portion 106 extends through an opening surgically formed between the passageway 116 and the passageway 118, i.e., the interconnecting passageway 130.

[0360] The expanded end portions 102, 104 of the device 100 are elastic and apply an outward radial force against the inner walls of the passageways 116, 118. Due to the radial rigidity of the end portions 102, 104 of the device 100, the end portions 102, 104 are held or retained in place within their respective passageways 116, 118. Thereby, displacement of the device 100 within the passageways 116, 118 is prevented or reduced. In this way, the end portions 102, 104 of the device 100 can retain or fix the device 100 in place while providing or maintaining the flow of fluid through the lumen 110 of the tube 108 (FIG. 8) during use. In this way, the device 100 can act as a shunt between the first passageway 116 and the second passageway 118.

[0361] The intermediate portion 106 of the device 100 can be made flexible, for example, to allow the intermediate portion 106 to form an "S" shape formed by combining the first passageway 116, the second passageway 118, and the interconnecting passageway 130 (FIG. 9). The flexible intermediate portion 106 can allow the end portions 102, 104 of the device 100 to move relative to each other in response to relative movement of the passageways 116, 118.

[0362] In an embodiment where the intermediate portion 106 does not include a wire mesh but includes the flexible polymer material of the tube 108, the intermediate portion 106 can be made less susceptible to damage due to mesh fatigue caused by periodic stress or other stress applied by, for example, the relative movement of the passages 116, 118.

[0363] The intermediate portion 106 of the device 100 has sufficient elasticity to maintain the expansion of the interconnecting passage 130, so that the interconnecting passage 130 remains open to provide or maintain the blood flow path from the artery 116 to the vein 118 by the lumen 110 of the tube 108 (FIG. 8). Thereby, the blood flow from the artery 116 to the vein 118 by the interconnecting passage 130 can be provided or maintained through the lumen 110 of the tube 108. The device 100 at least partially supports the artery 116, the vein 118 and the interconnecting passage 130 to provide a path for fluid communication through the device 100.

[0364] The proximal end portion 102 and the distal end portion 104 of the device 100 are configured such that, for example, as shown in FIG. 9, when the distal end portion 104 of the device 100 is deployed within the vein 118 and the proximal end portion 102 of the device 100 is deployed within the artery 116, the diameter of the expanded distal end portion 104 is sufficient to hold the distal end portion 104 within the vein 118, and the diameter of the expanded proximal end portion 102 is sufficient to hold the proximal end portion 102 within the artery 116. Thus, the diameter of the proximal end portion 102 can be different from the diameter of the distal end portion 104. By selecting suitable diameters for the end portions 102, 104 and the intermediate portion 106, the device 100 can be fabricated to fit a particular anatomical structure and / or the anatomical structure of an individual patient.

[0365] As shown, for example, in FIG. 9, an exemplary procedure is described herein for positioning the device 100 of FIG. 8 to provide a shunt between an occluded artery 116 and a vein 118 (e.g., between a coronary artery 116 and a coronary vein 118, or between a peripheral artery 116 and a peripheral vein 118) to achieve retrograde perfusion of arterial blood.

[0366] A catheter can be inserted into the patient's arterial system, usually through a small incision made within the patient's groin region. The catheter is fed into the artery 116 and guided to a position upstream of the occlusion site at a location that is parallel or substantially parallel to the vein 118, e.g., proximate to the vein 118. A hollow needle is deployed from the catheter, passed through the wall of the artery 116, through the interstitial tissue 132 separating the artery 116 and the vein 118, and through the wall of the vein 118. This path of the needle creates an interconnecting passageway or opening 130, thereby enabling blood to flow between the artery 116 and the vein 118. The deployment of the needle can be guided, for example, by a transmitter (e.g., a directional ultrasonic transmitter) connected to the catheter within the artery 116 and a receiver (e.g., an omnidirectional ultrasonic receiver) connected to the catheter within the vein 118, or vice versa, by a receiver connected to the catheter within the vein 116 and a transmitter connected to the catheter within the artery 118, and also as described in U.S. Patent Application No. 11 / 662,128. Other methods of forming the opening 130 are also possible (e.g., using other types of guides as described herein from the vein to the artery, whether or not a directional ultrasonic guide is used).

[0367] Before withdrawing the hollow needle from the passageway 130, a guide wire (e.g., as described with respect to the guide wire 14 of FIG. 3) is inserted through the needle and into the vein 118. Next, the needle is retracted while leaving the guide wire in place within the artery 116, the passageway 130, and the vein 118. Next, the catheter carrying the needle can be withdrawn from the patient's body. The guide wire can be used to further guide the catheter into the interconnecting passageway 130 between the artery 116 and the vein 118.

[0368] The catheter carrying the non-expanded device 100 is guided by a guide wire, for example through a rapid exchange lumen or through lumen 110, and advances towards the interconnecting passage 130. The catheter can include, for example, a balloon catheter configured to expand at least a portion of the device 100 and / or a catheter configured to self-expand at least a portion of the device 100. The distal end portion 104 of the device 100 enters into the vein 118 through the interconnecting passage 130, and the proximal end portion 102 remains in the artery 116. The intermediate portion 106 of the device 100 is at least partially within the passage 130 and at least partially within the artery 116 and the vein 118. The intermediate portion 106 bends to take a curved configuration, i.e., an "S" shaped configuration, according to the anatomical structure of the corresponding site. By taking such a bend, the shape of the intermediate portion 106 extending optionally through the interconnecting passage 130 and into at least one of the passages 116, 118 can be made to conform at least to the shape of the interconnecting passage 130.

[0369] The distal end portion 104 of the device 100 is expanded to increase the diameter of the distal end portion 104 and to lodge the distal end portion 104 against the inner wall of the vein 118, for example by balloon inflation or by self-expansion. The catheter can be adapted to expand the intermediate portion 106 of the device 100, for example by balloon inflation, thereby widening, i.e., enlarging, the interconnecting passage 130 and obtaining blood flow (e.g., sufficient blood flow) from the artery 116 to the vein 118. The proximal end portion 102 of the device 100 is expanded to increase the diameter of the proximal end portion 102 and to lodge the proximal end portion 102 against the inner wall of the artery 116, for example by inflating a balloon or by self-expansion.

[0370] For example, after expanding the end portions 102, 104 of the device 100 by self-expansion and / or balloon expansion, the catheter and guide wire are withdrawn from the patient's body, regardless of whether the expansion after deployment is increased or not. In this way, as shown in FIG. 9, the device 100 is placed or fixed at a predetermined position within the vein 118, artery 116, and the interconnecting passage 130. In embodiments where the device 100 includes a stent graft, such a passage can be blocked by a graft that can form a fluid-tight passage between the artery 116 and the vein 118, thereby preventing or blocking the antegrade flow of blood within the vein 118, and the graft can be additional or alternative to the blocking material within the vein 118.

[0371] The catheter can be adapted to selectively expand the proximal end portion 102, the distal end portion 104, and / or the intermediate portion 106 of the device 100 individually or in combination, by means such as, for example, two or more separate inflatable balloons or balloon portions, a single balloon configured to expand all portions of the device 100 simultaneously, or a single balloon configured to expand one or more selected portions of the device 100. For example, the end portions 102, 104 can be self-expanding, and the intermediate portion 106 can be expanded by a balloon to expand the passageway 130. In some embodiments including balloon expansion, all or selected portions of the device 100 can be expanded simultaneously, for example, by a balloon extending over the entire length of the device 100, or selectively, by a plurality of longitudinally spaced balloons configured to selectively inflate selected portions of the device 100, and / or sequentially by one balloon or a plurality of balloons. In some embodiments including at least partial self-expansion, all or selected portions of the device 100 can be expanded, for example, by retracting proximally a sheath that covers or surrounds the device 100, whereby the device 100 can be deployed from distal to proximal as the sheath retracts proximally. It is also possible to deploy the device 100 from proximal to distal, and to first deploy the device 100 from the middle and then to both ends. In some embodiments, for example, embodiments in which the device 100 is at least partially conical or tapered, a conical or tapered balloon can be used to expand the device 100 at least partially. In some such embodiments, the portion of the balloon proximate to the vein 118 can have a larger diameter than the portion of the balloon proximate to the artery 116, such that, for example, the device 100 can be configured to change the diameter of the vein in response to any increase in pressure or blood flow within the vein 118.

[0372] The treatment can also include other steps. For example, before deploying the device 100, the balloon catheter can be guided into the interconnecting passage 130 and positioned such that the inflatable balloon portion of the catheter is within the interconnecting passage 130. When the balloon is inflated, the balloon presses against the wall of the interconnecting passage 130 to widen, i.e., expand, the interconnecting passage 130, facilitating subsequent insertion of the device 100.

[0373] FIG. 10 shows another device 134 that provides fluid flow through at least one passage. The device 134 has a mesh 136 and a polymeric tube 108. The mesh 136 is shown as being outside the polymeric tube 108, but as described herein, additionally or alternatively, it may be inside the polymeric tube and / or within the polymeric tube 108. As described with respect to the device 100, the device 134 has a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. In the embodiment shown in FIG. 10, the mesh 136 extends along the entire length of the device 134, including along the intermediate portion 106.

[0374] In some embodiments, the spacing of the filaments or struts of the mesh 136 varies along the length of the device 134. For example, the winding density of a woven filament mesh or a laminated filament mesh can be varied, and / or the window size pattern of a cut mesh can be varied.

[0375] In some embodiments, the spacing can be relatively small at the proximal end portion 102 and the distal end portion 104 and relatively large at the intermediate portion 106. In other words, the density of the mesh 136 or the window size can be relatively small at the intermediate portion 106 and relatively large at the end portions 102, 104. In some such embodiments, the intermediate portion 106 can be more flexible than the end portions 102, 104. The relatively rigid end portions 102, 104 can engage the passageway and be retained therein. The mesh 136 at the intermediate portion 106 may be subject to stresses such as repetitive stress during use, but due to the relatively high flexibility of the intermediate portion 106 resulting from the low density or window size, the intermediate portion 106 can flex in response to the stress, making it possible for the impact of the stress to be small. Accordingly, the risk of fatigue failure of the filaments or struts 138 of the device 134, particularly the mesh 136, can be reduced compared to a device having uniform flexibility along its entire length.

[0376] In some embodiments, the spacing can be relatively large at the proximal end portion 102 and the distal end portion 104 and relatively small at the intermediate portion 106. In other words, the density of the mesh 136 can be relatively high at the intermediate portion 106 (or the window size of the mesh 136 can be relatively small) and relatively small at the end portions 102, 104 (or the window size of the mesh 136 can be relatively large). In some such embodiments, the intermediate portion 106 can have sufficient radial rigidity to prevent or inhibit crushing of the passageway 130, but can still have sufficient flexibility to flex in response to stresses such as repetitive stress. The end portions 102, 104 can engage the passageway and be retained therein.

[0377] FIG. 11 shows another device, namely an implant or prosthesis 140, which provides for the flow of fluid through at least one passageway. As described with respect to device 100, device 140 has a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. Device 140 includes a polymeric tube 108 and a support structure having a first mesh 142 and a second mesh 144. The first mesh 142 extends from the proximal end portion 102 toward (e.g., into) the intermediate portion 106 and optionally into the distal end portion 104. The second mesh 144 extends from the distal end portion 104 toward (e.g., into) the intermediate portion 106 and optionally into the proximal end portion 102. Thereby, meshes 142, 144 overlap each other at least in the intermediate portion 106. Meshes 142, 144 can both be outside the tube 108, inside the tube 108, or embedded within the tube 108, or one mesh can be outside the tube 108, inside the tube 108, or embedded within the tube 108 while the other mesh is different, e.g., one mesh is inside the tube 108 and the other mesh is outside the tube 108. Meshes 142, 144 can be formed, for example, by braiding wires in a lattice configuration around or inside the polymeric tube 108, by placing cut tubes around or inside the polymeric tube 108, by being embedded within the polymeric tube 108, by combinations thereof, etc.

[0378] In some embodiments, the density of the meshes 142, 144 is relatively high at their respective end portions 102, 104 (i.e., the window sizes of the meshes 142, 144 are relatively small), and the density decreases (i.e., the window size increases) towards the intermediate portion 106. The combined braiding density (e.g., the braiding density of both meshes 142, 144 combined together) can be lower in the intermediate portion 106 than in the end portions 102, 104, i.e., the combined window size (e.g., the window sizes of both meshes 142, 144 combined together) can be larger in the intermediate portion 106 than in the end portions 102, 104. In some such embodiments, the intermediate portion 106 is relatively flexible compared to the end portions 102, 104. In some embodiments, the meshes 142, 144 do not extend into the intermediate portion, and the absence of the meshes can make the intermediate portion 106 relatively flexible compared to the end portions 102, 104. In some embodiments, as the window size increases (e.g., longitudinally along the tapered portion of the device 140), the density decreases, the coverage range of the mesh decreases, and / or the porosity increases because the width of the struts and / or filaments is substantially constant or does not increase at the same rate as the window size, thus potentially resulting in a change in flexibility along the longitudinal length.

[0379] The first mesh 142 and the second mesh 144 can include various materials, thereby making it possible to optimize the respective characteristics of each of the distal end portion 102 and the proximal end portion 104 of the device 140 for a specific use of the device 140. For example, the second mesh 144 at the distal end portion 104 of the device 140 can include a relatively flexible metal alloy to facilitate insertion into an interconnecting passage between two blood vessels, whereas the first mesh 142 at the proximal end portion 102 of the device 140 can include a relatively inelastic metal alloy to provide a high degree of resistance to the proximal end portion 104 to firmly retain the device 140 in place. The first mesh 142 and the second mesh 144 can have the same material composition (e.g., both include nitinol) but different wire diameters (gauges) or strut thicknesses.

[0380] FIG. 12 shows another device, namely an implant or prosthesis 150, that provides fluid flow through at least one passage. The device 150 has a support structure (e.g., a stent) 152 and a graft 154. As described with respect to the device 100, the device 150 has a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. The proximal end portion 102 has a cylindrical or substantially cylindrical portion, and the distal end portion 104 has a cylindrical or substantially cylindrical portion. The diameter of the proximal end portion 102 is smaller than the diameter of the distal end portion 104. In some embodiments, the diameter of the proximal end portion 102 is larger than the diameter of the distal end portion 104. The intermediate portion 106 has a tapered or frustoconical shape between the proximal end portion 102 and the distal end portion 104. The stent 152 can include filaments (e.g., woven, laminated), cut tubes or cut sheets, and / or combinations thereof.

[0381] The parameters of the stent 152 may be uniform or substantially uniform over a portion and / or multiple portions, or may vary within a portion and / or between multiple portions. For example, the stent 152 may include a cut tube or cut sheet at the proximal end portion 102, the stent 152 may include a cut tube or cut sheet at the distal end portion 102, and the stent 152 may include filaments (e.g., woven or laminated) at the intermediate portion 106. Some such embodiments can provide excellent retention by the proximal end portion 102 and distal end portion 104, and excellent flexibility of the intermediate portion 106 (e.g., size of the third passage and adaptability to dynamic stress).

[0382] The stent 152 can include various materials in various portions. For example, the stent 152 can include cobalt chromium and / or tantalum at the proximal end portion 102, the stent 152 can include nitinol at the distal end portion 104, and the stent 152 can include nitinol at the intermediate portion 106. Some such embodiments can provide excellent retention and / or wall juxtaposition by the device 150 in each deployment region (e.g., the proximal end portion 102 that engages the arterial wall, the distal end portion 104 that engages the venous wall, and the intermediate portion 106 that engages the sidewall of the passage between the artery and the vein). In some embodiments where the distal end portion 104 is self-expanding, the distal end portion 104 can be adapted by changing the vascular diameter, for example, by further self-expansion (e.g., when the venous diameter increases due to an increase in pressure or blood flow).

[0383] Combinations of the material and type of the support structure are also conceivable. For example, the stent 152 may include a cut tube or cut sheet including cobalt chromium and / or tantalum at the proximal portion, the stent 152 may include a cut tube or cut sheet including nitinol at the distal end portion 104, and the stent 152 may include filaments including nitinol at the intermediate portion 106.

[0384] In an embodiment, the stent 152 has at least a portion including a cut tube or a cut sheet, and the cut patterns may be the same. For example, the cut patterns may be the same at the proximal end portion 102 and the distal end portion 104, but are proportional to the change in diameter. In some embodiments, the window size or the strut density is uniform or substantially uniform within the portions 102, 104, 106, within two or more of the portions 102, 104, 106, and / or from one end of the stent 152 to the other end of the stent 152. In an embodiment where the stent 152 has at least one portion including a filament, the winding may be the same. For example, the winding may be the same at the proximal end portion 102 and the distal end portion 104, but changes with the change in diameter. In some embodiments, the winding density or the porosity is uniform or substantially uniform within the portions 102, 104, 106, within two or more of the portions 102, 104, 106, and / or from one end of the stent 152 to the other end of the stent 152. In an embodiment where the stent 152 has at least one portion including a cut tube or a cut sheet and at least one portion including a filament, the cut pattern and the winding may be configured to obtain a uniform or substantially uniform density. For example, as described herein, non-uniformity is also conceivable.

[0385] The graft 154 can include a material and an attachment to the stent 152 as described for the tube 108. The graft 154 generally forms a liquid-tight passage for at least a portion of the device 150. The graft 154 is shown as being only around the intermediate portion 106, but may extend along the entire length of the device 150 or may partially overlap within at least one of the cylindrical end portions 102, 104.

[0386] FIG. 13 shows another device 160 that provides a flow of fluid through at least one passageway. The device 160 has a support structure (e.g., a stent) and a graft 164. As described with respect to device 100, device 160 has a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. The proximal end portion 102 has a tapered or frustoconical portion, and the distal end portion 104 has a tapered or frustoconical portion. The diameter of the proximal end of the proximal end portion 102 is smaller than the diameter of the distal end of the distal end portion 104. In some embodiments, the diameter of the proximal end of the proximal end portion 102 is larger than the diameter of the distal end of the distal end portion 104. The intermediate portion 106 has a tapered or frustoconical shape between the proximal end portion 102 and the distal end portion 104. In some embodiments, the inclination angles of portions 102, 104, 106 are the same or substantially the same (e.g., as shown in FIG. 13). In some embodiments, the inclination angle of at least one portion is sharper than that of at least one other portion, i.e., narrower than that of at least one other portion. The frustoconical proximal end portion 102 and distal end portion 104 can enable better retention within the body passageway, for example, because arteries taper as they move away from the heart and veins taper as they move towards the heart, and the end portions 102, 104 can be configured to at least partially correspond to such anatomical tapers.

[0387] FIG. 12 shows an apparatus 150 having a first cylindrical or linear portion, a conical or tapered portion, and a second cylindrical or linear portion. FIG. 13 shows an apparatus 160 having one or more conical or tapered sections (e.g., the entire apparatus 160 is conical or tapered, or has a plurality of conical or tapered sections). In some embodiments, a combination of apparatuses 150, 160 may be contemplated. For example, the apparatus may have a cylindrical or linear portion, and the remaining portion of the apparatus may have a conical or tapered portion. In some such embodiments, the apparatus can have a length of from about 1 cm to about 10 cm (e.g., about 5 cm), a cylindrical or linear portion having a diameter of from about 1 mm to about 5 mm (e.g., about 3 mm) and a length of from about 0.5 cm to about 4 cm (e.g., about 2 cm), and a conical or tapered portion having a diameter that tapers from the diameter of the cylindrical or linear portion to a diameter of from about 3 mm to about 10 mm (e.g., about 5 mm) and a length of from about 1 cm to about 6 cm (e.g., about 3 cm). Such an apparatus may not have another subsequent cylindrical or conical portion.

[0388] As described above with respect to support structure 152, support structure 162 can include filaments (e.g., braids, laminates), cut tubes or cut sheets, the same material, different materials, and combinations thereof.

[0389] Graft 164 can include materials and attachment to stent 162 as described for tube 108. Graft 164 generally forms a liquid-tight passage for at least a portion of apparatus 160. Graft 164 is shown as being only around intermediate portion 106, but may extend the entire length of apparatus 160 or may partially overlap within at least one of frustoconical end portions 102, 104.

[0390] In some embodiments, a combination of device 150 and device 160 may be contemplated. For example, the proximal end portion 102 can be cylindrical or substantially cylindrical (such as in device 150), and the distal end portion 104 can be tapered or frustoconical (such as in device 160), and the proximal end portion 102 has a diameter larger than the distal end of the distal end portion 104. In another example, the proximal end portion 102 can be tapered or frustoconical (such as in device 160), and the distal end portion 104 can be cylindrical or substantially cylindrical (such as in device 150), and the proximal end of the proximal end portion 102 has a diameter larger than the distal end portion 104. In each example, the intermediate portion 106 can have a tapered or frustoconical shape between the proximal end portion 102 and the distal end portion 104.

[0391] Exemplary deployment devices for the implantable devices described herein are described in U.S. Patent Application No. 12 / 545,982, filed August 24, 2009, and U.S. Patent Application No. 13 / 486,249, filed June 1, 2012, the entire contents of each of those U.S. patent applications being incorporated herein by reference. The device generally has a handle with a trigger that can be actuated by a user at the proximal end and, at the distal end, a combination of tubular members configured to be pushed and / or pulled upon actuation of the trigger to release the device. Other delivery devices may also be contemplated. The delivery device can have a portion slidable over a guidewire (e.g., manipulated between an artery and a vein by a tissue crossing needle) and / or be trackable through the lumen of a catheter.

[0392] Although several embodiments and examples have been shown and described in detail herein, various combinations, sub-combinations, modifications, variations, substitutions, and omissions of the specific features and aspects of those embodiments can be contemplated, some of which are described herein by way of example only.

[0393] Devices, such as stents, meshes, support structures of the devices, etc., can be self-expanding. For example, the mesh can include a shape memory material such as Nitinol that is capable of returning to a preset shape after being deformed. In some embodiments, the stent may be fabricated in the desired shape in the expanded form and can be compressed to fit inside a sleeve for delivery to a vascular site through a catheter. To deploy and expand the stent, the sleeve is withdrawn from the stent to allow the shape memory material to return to its preset shape, thereby enabling the stent to be placed in the passageway and, if the stent has sufficient radial strength, to expand the passageway. The use of a balloon catheter is not required to expand a fully self-expanding stent but can be used, for example, to enhance or optimize deployment.

[0394] The device can have one or more self-expanding portions and one or more portions that can be expanded by deformation, for example, using a balloon catheter. For example, in the embodiment shown in FIG. 11, the first mesh 142 may include stainless steel that can be expanded by a balloon catheter, and the second mesh 144 may include Nitinol for self-expanding upon expansion.

[0395] With respect to any of the embodiments described herein, the polymeric tube 108 having grafts 154, 164 can include any suitable compliant or flexible polymer such as PTFE, silicone, polyethylene terephthalate (PET), polycarbonate-based aromatic biopersistent thermoplastic polyurethane elastomers (e.g., ChronoFlex C® 80A and 55D medical grades available from AdvanSource Biomaterials, Wilmington, Massachusetts), polyurethanes, combinations thereof, etc. The polymeric tube 108 can include biodegradable polymers, bioabsorbable polymers or biocompatible polymers (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycolic lactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.). The polymer can be in tube form before interacting with a support structure (e.g., a stent), or can be formed on, inside and / or around a support structure (e.g., a stent). For example, the polymer can include spun fibers, dip coatings, combinations thereof, etc. In some embodiments, for example, where the device is to be deployed in a single blood vessel, the tube can be omitted from the device. In some such embodiments, the middle portion of the stent can have a mesh with a low winding density or a high window size, while the end portions of the stent have a mesh with a higher winding density or a lower window size, and the mesh is generally tubular so as to define a path for fluid flow through the center of the mesh. In some embodiments, the polymeric tube 108 has a lip (e.g., including the same material or different materials), and the lip can help form a liquid-tight seal between the polymeric tube 108 and the body passageway. The seal can be angled, for example, for angled positioning of the polymeric tube 108 between body passageways. In some embodiments, the polymeric tube 108 can extend longitudinally beyond the support structure in at least one direction, and the extending portion is supported by the support structure.

[0396] The mesh can comprise any suitable material such as nickel, titanium, chromium, cobalt, tantalum, platinum, tungsten, iron, manganese, molybdenum, combinations thereof (e.g., nitinol, cobalt chromium, stainless steel), etc. The mesh can comprise a biodegradable polymer, a bioabsorbable polymer or a biocompatible polymer (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycolic lactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.) and / or glass, and may be without metal. As previously described with reference to, for example, FIG. 11, various materials may be used in some portions of the mesh or within the same mesh. For example, the mesh 114 at the distal end portion 104 of the device 100 and the mesh 112 at the proximal end portion 102 may comprise different materials. In another example, the mesh 112 and / or the mesh 114 may comprise a metal alloy (e.g., comprising cobalt, chromium, nickel, titanium, combinations thereof, etc.) combined with various types of metal alloys (e.g., a shape memory alloy combined with a non-shape memory alloy, a first shape memory alloy combined with a second shape memory alloy different from the first shape memory alloy, a clad material (e.g., comprising a core comprising a radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc.)), and / or a non-metallic material such as a polymer (e.g., polyester fiber), carbon, and / or bioabsorbable glass fiber. In some embodiments, at least one of the meshes 112, 114 comprises nitinol and stainless steel. The nitinol can enable some self-expansion (e.g., partial self-expansion and / or full self-expansion), in which case the mesh can be further expanded using, for example, a balloon.

[0397] Although generally shown in FIGS. 8, 10, and 11 as a woven filament mesh, any other structure that can provide the desired degree of elasticity may also be used. For example, layers of filaments wound in opposite directions can be melted at both ends of the filaments to provide an expandable structure. In another example, a metal sheet can be cut (e.g., laser cut, chemically etched, plasma cut, etc.) to form perforations and then heat set within a tubular former, or a metal tube (e.g., a hypodermic tube) can be cut (e.g., laser cut, chemically etched, plasma cut, etc.) to form perforations. The cut tube (including the cut sheet wound into a tube) can be heat set to provide an expanded form.

[0398] Filaments or wires or ribbons that can be configured in a woven or knitted or layered or otherwise manner are generally elongated and have a cross-section such as circular, oval, square, rectangular, etc. Exemplary non-woven filaments can have a first filament layer wound in a first direction and a second filament layer wound in a second direction, and at least a portion of the filament ends can be joined together (e.g., by joining to an expandable ring). Exemplary knitting patterns include one over one, one over two, two over two, and / or combinations thereof, although other knitting patterns are also possible. At filament intersections, the filaments can be wound spirally, can intersect in a sliding relationship, and / or can be a combination thereof. The filaments can be in a loose state (e.g., joined together by a weave), and / or can be joined elements such as welds, sleeves, and / or combinations thereof. The ends of the filaments can be bent back, crimped to a ring (e.g., end crimping 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, combinations thereof, etc. The woven ends can include filament ends and / or bent-back filaments and can have continuous bubbles, fixed or unfixed filaments, welds, adhesives or other fusing means, radiopaque markers, combinations thereof, etc. The parameters of the filaments can be uniform or substantially uniform over a portion and / or multiple portions, or can vary within a portion and / or between multiple portions. For example, the proximal end portion 102 can have a first parameter, and the distal end portion 104 can have a second parameter different from the first knitting pattern. In another example case, the proximal end portion 102 and the distal end portion 104 can each have a first parameter, and the intermediate portion 106 can have a second parameter different from the first parameter. In yet another example case, at least one of the proximal end portion 102, the distal end portion 104, and the intermediate portion 106 can have both a first parameter and a second parameter different from the first parameter.The filament parameters can include, for example, filament type, filament thickness, filament material, amount of filament, weave pattern, layering, winding direction, pitch, angle, crossing type, filament bonding or lack thereof, filament end treatment, weave end treatment, layering end treatment, amount of layers, presence or absence of welds, radiopacity, braiding pattern, density, porosity, filament angle, braiding diameter, winding diameter, and shape setting.

[0399] The tube or sheet can be cut to form a strut pattern or a cell pattern, where the strut is the portion of the tube or sheet remaining after cutting, and the cell or perforation or window is the separated portion. The tube (e.g., hypodermic tube) can be cut directly, or the sheet can be cut and then wound to form a tube. The tube or sheet can be in the shape set before cutting or in the shape set after cutting. The tube or sheet can be welded or otherwise joined to itself, to another tube or sheet, to a filament, to a graft material, etc. Cutting can be done by a laser, a chemical etching solution, a plasma, a combination thereof, etc. Exemplary cut patterns include a helical spiral, a woven pattern, a coil pattern, individual ring patterns, continuous ring patterns, continuous bubble patterns, discrete bubble patterns, combinations thereof, etc. In embodiments including continuous rings, the rings can be connected using flexible connectors, non-flexible connectors, and / or combinations thereof. In embodiments including continuous rings, the connectors of the rings (e.g., flexible, non-flexible, and / or combinations thereof) intersect the peaks of the rings, the valleys of the rings, the middle portions of the struts, and / or combinations thereof (e.g., peak to peak, valley to valley, middle to middle, peak to valley, peak to middle, valley to middle, valley to peak, middle to peak, middle to valley). The tube or sheet or section can be ground and / or polished before cutting or after cutting. For example, internal ridges can be formed to assist fluid flow. The parameters of the cut tube or cut sheet can be uniform or substantially uniform over a portion and / or multiple portions, or can vary within a portion and / or between multiple portions. For example, the proximal end portion 102 can have a first parameter, and the distal end portion 104 can have a second parameter different from the first parameter. In another example, the proximal end portion 102 and the distal end portion 104 can each have a first parameter, and the middle portion 106 can have a second parameter different from the first parameter. In yet another example, at least one of the proximal end portion 102, the distal end portion 104, and the middle portion 106 can have both a first parameter and a second parameter different from the first parameter.Cut tube parameters or sheet parameters can include, for example, radial strut thickness, circumferential strut width, strut shape, cell shape, cut pattern, cut type, material, density, porosity, tube diameter, and shape settings.

[0400] In some embodiments, perforations may result in a mesh having a relatively flexible middle portion and a relatively rigid end portion. Alternatively, the support structure may be a continuous foam disposed within the tube.

[0401] The filaments of the stent, the stent graft, or a part thereof, and / or the struts of the cut stent, the stent graft, or a part thereof can have a surface modified to carry agents such as, for example, a thrombosis modifier, a fluid flow modifier, an antibiotic, etc. The filaments of the stent, the stent graft, or a part thereof, and / or the struts of the cut stent, the stent graft, or a part thereof can be at least partially covered by a coating containing agents such as, for example, a thrombosis modifier, a fluid flow modifier, an antibiotic, etc., embedded in one polymer layer or a series of polymer layers that may be the same as or different from the polymer tube 108.

[0402] The thickness (e.g., diameter) of the filaments of a stent, a stent graft, or a portion thereof, and / or the struts of a cut stent, a stent graft, or a portion thereof is from about 0.0005 inches to about 0.02 inches, from about 0.0005 inches to about 0.015 inches, from about 0.0005 inches to about 0.01 inches, from about 0.0005 inches to about 0.008 inches, from about 0.0005 inches to about 0.007 inches, from about 0.0005 inches to about 0.006 inches, from about 0.0005 inches to about 0.005 inches, from about 0.0005 inches to about 0.004 inches, from about 0.0005 inches to about 0.003 inches, from about 0.0005 inches to about 0.002 inches, from about 0.0005 inches to about 0.001 inches, from about 0.001 inches to about 0.02 inches, from about 0.001 inches to about 0.015 inches, from about 0.001 inches to about 0.01 inches, from about 0.001 inches to about 0.008 inches, from about 0.001 inches to about 0.007 inches, from about 0.001 inches to about 0.006 inches, from about 0.001 inches to about 0.005 inches, from about 0.001 inches to about 0.004 inches, from about 0.001 inches to about 0.003 inches, from about 0.001 inches to about 0.002 inches, from about 0.002 inches to about 0.02 inches, from about 0.002 inches to about 0.015 inches, from about 0.002 inches to about 0.01 inches, from about 0.002 inches to about 0.008 inches, from about 0.002 inches to about 0.007 inches, from about 0.002 inches to about 0.006 inches, from about 0.002 inches to about 0.005 inches, from about 0.002 inches to about 0.004 inches, from about 0.002 inches to about 0.003 inches, from about 0.003 inches to about 0.02 inches, from about 0.003 inches to about 0.015 inches, from about 0.003 inches to about 0.01 inches, from about 0.003 inches to about 0.008 inches, from about 0.003 inches to about 0.007 inches, from about 0.003 inches to about 0.006 inches, from about 0.003 inches to about 0.005 inches, from about 0.003 inches to about 0.004 inches, from about 0.004 inches to about 0.02 inches, from about 0.004 inches to about 0.015 inches, from about 0.004 inches to about 0.01 inches, from about 0.004 inches to about 0.008 inches, from about 0.004 inches to about 0.007 inches, from about 0.004 inches to about 0.006 inches, from about 0.004 inches to about 0.005 inches, from about 0.005 inches to about 0.0.02 inches, from about 0.005 inches to about 0.015 inches, from about 0.005 inches to about 0.01 inches, from about 0.005 inches to about 0.008 inches, from about 0.005 inches to about 0.007 inches, from about 0.005 inches to about 0.006 inches, from about 0.006 inches to about 0.02 inches, from about 0.006 inches to about 0.015 inches, from about 0.006 inches to about 0.01 inches, from about 0.006 inches to about 0.008 inches, from about 0.006 inches to about 0.007 inches, from about 0.007 inches to about 0.02 inches, from about 0.007 inches to about 0.015 inches, from about 0.007 inches to about 0.01 inches, from about 0.007 inches to about 0.008 inches, from about 0.008 inches to about 0.02 inches, from about 0.008 inches to about 0.015 inches, from about 0.008 inches to about 0.01 inches, from about 0.01 inches to about 0.02 inches, from about 0.01 inches to about 0.015 inches, or from about 0.015 inches to about 0.02 inches. Other thicknesses may also be considered, including thicknesses greater than or less than the specified thickness. Filaments and / or struts containing some materials (e.g., biodegradable materials, materials with low resilience, etc.) may be thicker than the specified thickness.

[0403] The thickness of the filament and / or strut can be based on, for example, at least one of the device or device part size (e.g., diameter and / or length), porosity, radial strength, material, amount of filament and / or strut, cut pattern, weave pattern, layering pattern, etc. For example, a large device or device part used to treat a large blood vessel such as a coronary blood vessel may be useful with a greater filament and / or strut thickness (e.g., greater than about 0.006 inches), an intermediate-sized device or device part used to treat an intermediate-sized blood vessel such as a peripheral blood vessel may be useful with an intermediate-sized filament and / or strut thickness (e.g., from about 0.003 inches to about 0.006 inches), and a small device or device part used to treat a small blood vessel such as a vein and a neurovascular vessel may be useful with a small filament and / or strut thickness (e.g., less than about 0.003 inches).

[0404] The inner diameter or outer diameter of a stent, stent graft, or a first end portion, second end portion, middle portion, or sub - portion of a stent can be, for example, when taking into account the thickness of filaments or struts, about 1 mm to about 12 mm, about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 6 mm, about 1 mm to about 4 mm, about 1 mm to about 2 mm, about 2 mm to about 12 mm, about 2 mm to about 10 mm, about 2 mm to about 8 mm, about 2 mm to about 6 mm, about 2 mm to about 4 mm, about 4 mm to about 12 mm, about 4 mm to about 10 mm, about 4 mm to about 8 mm, about 4 mm to about 6 mm, about 6 mm to about 12 mm, about 6 mm to about 10 mm, about 6 mm to about 8 mm, about 8 mm to about 12 mm, about 8 mm to about 10 mm, or about 10 mm to about 12 mm. Some such diameters may be suitable for treating, for example, coronary blood vessels. The inner diameter or outer diameter of a stent, stent graft, or a portion of a stent can be, for example, when taking into account the thickness of filaments or struts, about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 6 mm, about 1 mm to about 4 mm, about 1 mm to about 2 mm, about 2 mm to about 10 mm, about 2 mm to about 8 mm, about 2 mm to about 6 mm, about 2 mm to about 4 mm, about 4 mm to about 10 mm, about 4 mm to about 8 mm, about 4 mm to about 6 mm, about 6 mm to about 10 mm, about 6 mm to about 8 mm, or about 8 mm to about 10 mm. Some such diameters may be suitable for treating, for example, veins. The inner diameter or outer diameter of a stent, stent graft, or a portion of a stent can be, for example, when taking into account the thickness of filaments or struts, about 6 mm to about 25 mm, about 6 mm to about 20 mm, about 6 mm to about 15 mm, about 6 mm to about 12 mm, about 6 mm to about 9 mm, about 9 mm to about 25 mm, about 9 mm to about 20 mm, about 9 mm to about 15 mm, about 9 mm to about 12 mm, about 12 mm to about 25 mm, about 12 mm to about 20 mm, about 12 mm to about 15 mm, about 15 mm to about 25 mm, about 15 mm to about 20 mm, or about 20 mm to about 25 mm. Some such diameters may be suitable for treating, for example, peripheral blood vessels.The inner diameter or outer diameter of a stent, stent graft, or a portion of a stent, for example, considering the thickness of filaments or struts, can be about 20 mm to about 50 mm, about 20 mm to about 40 mm, about 20 mm to about 35 mm, about 20 mm to about 30 mm, about 30 mm to about 50 mm, about 30 mm to about 40 mm, about 30 mm to about 35 mm, about 35 mm to about 50 mm, about 35 mm to about 40 mm, or about 40 mm to about 50 mm. Some such diameters may be suitable for treating, for example, the aorta. Other diameters including diameters larger or smaller than the specified diameter can also be considered. The diameter of the device can indicate the diameter of the first end portion, the second end portion, or the intermediate portion, each of which may be in an expanded form or a non-expanded form. The diameter of the device can indicate the average diameter of the device when all parts of the device are in an expanded form or a non-expanded form.

[0405] The length of a stent, stent graft, or the first end portion, the second end portion, the intermediate portion, or a sub-portion of a stent can be about 5 mm to about 150 mm, about 5 mm to about 110 mm, about 5 mm to about 70 mm, about 5 mm to about 50 mm, about 5 mm to about 25 mm, about 5 mm to about 20 mm, about 5 mm to about 10 mm, about 10 mm to about 150 mm, about 10 mm to about 110 mm, about 10 mm to about 70 mm, about 10 mm to about 50 mm, about 10 mm to about 25 mm, about 10 mm to about 20 mm, about 20 mm to about 150 mm, about 20 mm to about 110 mm, about 20 mm to about 70 mm, about 20 m to about 50 mm, about 20 mm to about 25 mm, about 25 mm to about 150 mm, about 25 mm to about 110 mm, about 25 mm to about 70 mm, about 25 m to about 50 mm, about 50 mm to about 150 mm, about 50 mm to about 110 mm, about 50 mm to about 70 mm, about 70 mm to about 150 mm, about 70 mm to about 110 mm, or about 110 mm to about 150 mm. Other lengths including lengths longer or shorter than the specified length can also be considered.

[0406] The porosity of a stent, a stent graft, or a first end portion, a second end portion, an intermediate portion, or a sub-portion of a stent can be from about 5% to about 95%, from about 5% to about 50%, from about 5% to about 25%, from about 5% to about 10%, from about 10% to about 50%, from about 10% to about 25%, from about 25% to about 50%, from about 50% to about 95%, from about 50% to about 75%, from about 50% to about 60%, from about 60% to about 95%, from about 75% to about 90%, from about 60% to about 75%, and combinations thereof. The density of the stent can be inversely proportional to the porosity of the stent. The porosity of a portion of the stent covered by the graft can be about 0%. The porosity can vary depending on the purpose of some parts of the stent. For example, the intermediate portion may have a low porosity to increase the flow of fluid through the device, while the end portion may have a lower porosity to increase flexibility and wall juxtaposition.

[0407] FIG. 25A is a schematic side elevation view of yet another exemplary embodiment of a prosthesis 500. The prosthesis or stent or device 500 comprises and / or consists essentially of a plurality of filaments 502 woven into a woven structure. The stent 500 may be without a graft material, as will be described in more detail below.

[0408] The filament 502, which can also be described as a wire, ribbon, strand, etc., can be configured in a woven, braided, layered, or otherwise intersecting manner. The filament 502 is generally elongated and has a cross-section such as circular, oval, square, rectangular, etc. An exemplary non-woven filament can have a first filament layer wound in a first direction and a second filament layer wound in a second direction, and at least a portion of the filament ends are joined together (e.g., by being joined to an expandable ring). Exemplary woven patterns include one above one (e.g., as shown in FIG. 25A), one above two, two above two, and / or combinations thereof, although other woven patterns are also possible. At the intersections of the filaments 502, the filaments 502 can be wound spirally, can intersect in a sliding relationship, and / or can be a combination thereof. The filaments 502 can be in a loose state (e.g., joined together by a weave) and / or can include joining elements such as welds, sleeves, and / or combinations thereof. The ends of the filament 502 can be turned back and crimped to a ring (e.g., end crimping with a radiation-impermeable material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc., which can also act as a radiopaque marker), twisted, ball welded, joined, combinations thereof, etc. The woven ends can include the ends of the filaments 502 and / or the turned-back filaments 502 and can have continuous bubbles, fixed or unfixed filaments 502, welds, adhesives or other fusing means, radiopaque markers, combinations thereof, etc.

[0409] The stent 500 has open, uncoated regions between the pores 504 or filaments 502. The porosity of the stent 500 can be calculated as the outer surface area of the pores 504 divided by the total outer surface area of the stent 500. The porosity can be affected by parameters such as, for example, the number of filaments 502, the braiding angle 506, the size (e.g., diameter) of the filaments 502, and combinations thereof.

[0410] The porosity of the stent 500 can be less than about 50% (e.g., the covered area is slightly larger than the open area), about 0% (e.g., there is little open area) to about 50%, about 0% to about 45%, about 0% to about 40%, about 0% to about 35%, about 0% to about 30%, about 0% to about 25%, about 0% to about 20%, about 0% to about 15%, about 0% to about 10%, about 0% to about 5%, about 5% to about 50%, about 5% to about 45%, about 5% to about 40%, about 5% to about 35%, about 5% to about 30%, about 5% to about 25%, about 5% to about 20%, about 5% to about 15%, about 5% to about 10%, about 10% to about 50%, about 10% to about 45%, about 10% to about 40%, about 10% to about 35%, about 10% to about 30%, about 10% to about 25%, about 10% to about 20%, about 10% to about 15%, about 15% to about 50%, about 15% to about 45%, about 15% to about 40%, about 15% to about 35%, about 15% to about 25%, about 15% to about 20%, about 20% to about 50%, about 20% to about 45%, about 20% to about 40%, about 20% to about 35%, about 20% to about 25%, about 25% to about 50%, about 25% to about 45%, about 25% to about 40%, about 25% to about 35%, about 30% to about 50%, about 30% to about 45%, about 30% to about 40%, about 30% to about 35%, about 35% to about 50%, about 35% to about 45%, about 35% to about 40%, about 40% to about 50%, about 40% to about 45%, about 45% to about 50% and combinations thereof.

[0411] In some embodiments where the porosity is less than about 50%, under normal vascular pressure (e.g., pressure loss across the blood vessel, pressure loss from the inlet to the outlet), it can be made impossible for blood to perfuse through the sidewalls of the stent 500. In certain such embodiments, the blood flowing into the proximal end of the stent 500 can be directed through the lumen of the stent 500 towards the distal end of the stent 500 without using (e.g., substantially without using, without comprising, substantially without comprising) a graft material, but still without causing blood loss or substantial blood loss through the sidewalls of the stent 500. In contrast, in certain so-called "flow diverting stents", the porosity is specifically designed to be greater than about 50% to ensure perfusion to the outlet.

[0412] The density of the stent 500 can be inversely proportional to the porosity (for example, the outer surface area of the filament 502 divided by the total outer surface area of the stent 500). The density of the stent 500 can be from 100% minus the value of the porosity shown above.

[0413] The filament 502 is at a braiding angle 506 with respect to an axis perpendicular to the longitudinal axis of the stent 500 (for example, indicated by the exemplary dashed line in FIG. 25A). The braiding angle 506 can be in the range just over 90 degrees to just under 180 degrees. The braiding angle 506 can be an acute angle or an obtuse angle. In some embodiments, the braiding angle 506 is about 90 degrees to about 180 degrees, about 120 degrees to about 180 degrees, about 150 degrees to about 180 degrees, about 160 degrees to about 180 degrees, about 170 degrees to about 180 degrees, about 160 degrees to about 170 degrees, about 165 degrees to about 175 degrees, combinations thereof, etc. In some embodiments, the closer the braiding angle 506 is to 180 degrees, the greater the radial strength of the stent 500. An apparatus 500 with greater radial strength can assist in opening or maintaining an opening of a fistula (formed as described herein). Other factors such as the diameter of the filament 502, the material of the filament 502, the number of filaments 502, etc. can also affect the radial strength.

[0414] All of the filaments 502 may be the same, or some of the filaments 502 may have different parameters (for example, material, dimensions, combinations thereof, etc.). In some embodiments, some of the filaments 502 include a shape memory material (for example, including nitinol), and other filaments 502 include another material (for example, including aramid fibers (for example, Kevlar (registered trademark)), Dacron (registered trademark), biocompatible polymers, etc.). The shape memory material can provide a mechanical structure, and the other material can provide a low porosity (for example, due to the thick sidewall dimensions).

[0415] Figure 25B is a schematic side elevation view of yet another exemplary embodiment of the prosthesis 520. The prosthesis or stent or device 520 includes and / or consists essentially of a first plurality of filaments 522 woven together in a first weave structure and a second plurality of filaments 524 woven together in a second weave structure. The stent 520 may be without a graft material, as described in more detail herein. The first plurality of filaments 522 may be similar to the filaments 502 of the stent 500 described with respect to FIG. 25A. In some embodiments, the filaments 522 may not have sufficient radial force to open and maintain a fistula and / or juxtapose the arterial and / or venous sidewalls. In certain such embodiments, the filaments 524 may function as an auxiliary support structure to provide radial force. The filaments 524 may be radially outside the filaments 522 (e.g., as shown in FIG. 25B), radially inside the filaments 522, and / or integrated with the filaments 522 (e.g., such that the first and second weave structures are not readily separable). The filaments 524 may be of the same or different material, the same or different thickness, etc. as the filaments 522, and / or the filaments 524 may be woven with the same or different parameters (e.g., braiding angle) than the filaments 522 such that the filaments 524 obtain a greater radial force. The filaments 524 may be joined to the filaments 522 (e.g., to form a single deployable stent 520) or may be deployed separately. For example, if the filaments 522 are deployed after the filaments 524 are deployed, the filaments 524 may maintain the fistula open and the filaments 522 may be expanded substantially without reacting within the lumen formed by the filaments 524. In another example, if the filaments 524 are deployed after the filaments 522 are deployed, the filaments 524 may act as an expansion force against the portions of the filaments 522 that require an expansion force.

[0416] Although FIG. 25B shows the prosthesis 520 as including a second textile structure, the auxiliary support structure can additionally or alternatively include a helical coil, a cut hypodermic tube, combinations thereof, and the like. The determination of the porosity of the prosthesis 520 can be based primarily on the porosity of the first textile structure such that the auxiliary support structure can be designed to primarily provide a radial force (e.g., a force sufficient to open or keep open a fistula).

[0417] Although shown as uniform or substantially uniform over the length of the stent 500, the parameters of the stent 500 and the filaments 502 can vary over the length of the stent 500, as described, for example, with respect to FIG. 25C. Uniformity can have advantages such as reduced manufacturing cost, reduced need for precise placement, and / or others. Non-uniformity can allow for specialization or customization for specific properties and / or functions along various lengths and / or can have other advantages.

[0418] FIG. 25C is a schematic side elevation view of yet another exemplary embodiment of the prosthesis 540. The prosthesis or stent or device 540 comprises and / or consists essentially of a plurality of filaments 542 woven into a textile structure. The stent 540 may be without a graft material, as described in more detail herein. The stent 540 has a first longitudinal section or segment or portion 544 and a second longitudinal section or segment or portion 546. For example, parameters such as porosity (e.g., as shown in FIG. 25B), braiding angle, braiding type, parameters of the filaments 542 (e.g., diameter, material, etc.), the presence of an auxiliary support structure (e.g., an auxiliary support structure), stent diameter, stent shape (e.g., cylindrical, frustoconical), combinations thereof, etc. may be different between the first longitudinal section 544 and the second longitudinal section 546. The porosity may vary depending on the purpose of a particular portion of the stent 540. For example, the first longitudinal section 544 can be configured to be placed in an artery and a fistula and have a low porosity (e.g., less than about 50% as described with respect to the stent 500 of FIG. 25A), which can increase the flow of fluid through the stent 500. On the other hand, the second longitudinal section can be configured to be placed in a vein and have a higher porosity, which can improve flexibility and wall juxtaposition.

[0419] In some embodiments, the stent comprises and / or consists essentially of a low-porosity fabric configured to divert flow from an artery to a fistula, and has a first longitudinal section that does not comprise an auxiliary support structure; a second longitudinal section that comprises and / or consists essentially of a low-porosity fabric configured to divert blood flow through the fistula, and comprises an auxiliary support structure configured to open and maintain the fistula; and a third longitudinal section that comprises and / or consists essentially of a low-porosity fabric configured to divert flow from the fistula to a vein. In certain such embodiments, the first longitudinal section can be configured as stent 500 of FIG. 25A, and the third longitudinal section can be configured as stent 500 of FIG. 25A or stent 540 of FIG. 25C.

[0420] The difference between the first longitudinal section 544 and the second longitudinal section 546 can be imparted during manufacture (e.g., by braiding parameters, shaping, etc.) and / or in situ (e.g., during and / or after deployment (e.g., by stent packing)).

[0421] For example, other differences between the first longitudinal section 544 and the second longitudinal section 546 described in this specification (including, for example, laser cut portions, further longitudinal sections, etc.) are also conceivable. In some embodiments, the stent comprises a low-porosity woven body configured to divert flow from an artery to a fistula, and / or consists essentially of such a woven body, a first longitudinal section disposed in the fistula and configured to divert blood through the fistula and / or maintain the fistula open by diverting blood through the fistula, and / or consisting essentially of such a laser cut portion, a second longitudinal section, and a third longitudinal section comprising a low-porosity woven body configured to divert flow from the fistula to a vein, and / or consisting essentially of such a woven body. In certain such embodiments, the first longitudinal section can be configured as the stent 500 of FIG. 25A, and the third longitudinal section can be configured as the stent 500 of FIG. 25A or the stent 540 of FIG. 25C.

[0422] FIG. 27 schematically shows an exemplary embodiment of a prosthesis 720. With respect to the anatomical structure of FIG. 27, this prosthesis 720 will be described in more detail below. The prosthesis 720 has 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 can be such that even when substantially lacking a graft material, for example, by a low-porosity woven structure, fluid can flow substantially through the lumen of the prosthesis 720 without substantially flowing through the sidewalls.

[0423] In an embodiment where the prosthesis 720 is used in the peripheral vascular system, the first longitudinal section 722 can be described as an arterial section, the second longitudinal section 724 can be described as a venous section, and the third longitudinal section 726 can be described as a transition section. The first longitudinal section 722 is configured to juxtapose the side wall of the artery 700 or another lumen. For example, in the case of some peripheral arteries, the first longitudinal section 722 can have an expanded diameter of about 2 mm to about 4 mm (e.g., about 3 mm). The second longitudinal section 724 is configured to juxtapose the side wall of the vein 702 or another lumen. For example, in the case of some peripheral veins, the second longitudinal section 724 can have an expanded diameter of about 5 mm to about 7 mm (e.g., about 6 mm). In some embodiments, the second longitudinal section 724 and the third longitudinal section 726 can have a shape that includes a frustoconical shape that tapers from a smaller diameter to a larger diameter than the first longitudinal section 722, rather than being substantially cylindrical as shown in FIG. 27.

[0424] The length of the prosthesis 720 can be configured or sized to span the interstitial tissue T between the artery 700 and / or vein 702 such that (e.g., sufficient to prevent or inhibit movement or dislocation of the prosthesis 720 in the longitudinal direction) the prosthesis 720 is placed within the artery 700 and / or vein 702. For example, in the case of some peripheral arteries, the length of the first longitudinal section 722 in the expanded or deployed state can be from about 20 mm to about 40 mm (e.g., about 30 mm). In another example, in the case of some peripheral veins, the length of the second longitudinal section 724 in the expanded or deployed state can be from about 10 mm to about 30 mm (e.g., about 20 mm). In yet another example, in the case of some peripheral vascular systems, the length of the third longitudinal section 726 in the expanded or deployed state can be from about 5 mm to about 15 mm (e.g., about 10 mm). The overall length of the prosthesis 720 in the expanded or deployed state can be from about 30 mm to about 100 mm, from about 45 mm to about 75 mm (e.g., about 60 mm). Although the thickness of the interstitial tissue T is shown as about 2 mm, other dimensions may be considered depending on the specific anatomical structure of the deployed position. For example, other dimensions of the prosthesis 720, the first longitudinal section 722 and / or the second longitudinal section 724 described herein may also be considered.

[0425] The third longitudinal section 726 has a frustoconical or tapered shape that expands from a smaller diameter of the first longitudinal section 722 to the second longitudinal section 724. The transition points between the longitudinal sections 722, 724, 726 may or may not be clearly distinguishable. For example, it can also be stated that the transition section includes a part of the first longitudinal section 722 and the third longitudinal section 726, or it can also be stated that the third longitudinal section 726 includes a cylindrical portion having the same diameter as the first longitudinal section 722. The longitudinal sections 722, 724, 726 may be different from the shapes and dimensions described above and / or may be different in other respects (e.g., material, pattern, etc.). For example, one or more portions may be cylindrical, frustoconical, etc. as shown in FIGS. 12, 13 and 27 and described herein.

[0426] The first longitudinal section 722 and / or the third longitudinal section 726 can have a relatively high radial force, for example, a force configured to create and maintain a fistula opening, and the second longitudinal section 724 can have 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 braiding angle, etc. In some embodiments, the second longitudinal section 724 comprises a self-expanding stent, a woven stent with a low braiding angle, etc. Combinations of laser-cut stents, woven stents, different cut patterns, different woven patterns, etc. are described in more detail herein. In some embodiments, the longitudinal sections 722, 724, 726 can be integral or separate. The second longitudinal section 724 can be relatively flexible while having, for example, a relatively low radial force, thereby helping the second longitudinal section 724 to flex with the anatomical structure during a blood flow pulse.

[0427] In some embodiments, the second longitudinal section 724 and / or the third longitudinal section 726 can comprise some graft materials (including, for example, silicone). The graft material can block or prevent flow through the sidewall of the prosthesis 720 and / or can be used to carry a drug. For example, the graft material may or may not occlude the pores of a portion of the prosthesis 720 depending on the purpose of the graft material.

[0428] The proximal end and / or the distal end of the prosthesis 720 can be non-traumatic, for example, by having end treatments, low braiding angles, small filament diameters, combinations thereof, etc.

[0429] The radial strength or compression resistance of a stent, a stent graft, or a first end portion, a second end portion, an intermediate portion, or a sub-portion of a stent can be from about 0.1 N / mm to about 0.5 N / mm, from about 0.2 N / mm to about 0.5 N / mm, from about 0.3 N / mm to about 0.5 N / mm, from about 0.1 N / mm to about 0.3 N / mm, from about 0.1 N / mm to about 0.2 N / mm, from about 0.2 N / mm to about 0.5 N / mm, from about 0.2 N / mm to about 0.3 N / mm, or from about 0.3 N / mm to about 0.5 N / mm.

[0430] The values of some parameters of a stent, a stent graft, or a first end portion, a second end portion, an intermediate portion, or a sub-portion of a stent can be related (e.g., proportional) to each other. For example, the ratio of the thickness of a strut or filament to the diameter of the device portion having the strut or filament can be from about 1:10 to about 1:250, from about 1:25 to about 1:175, or from about 1:50 to about 1:100. In another example, the ratio of the length of a device or a device portion to the diameter of the device or the device portion can be from about 1:1 to about 50:1, from about 5:1 to about 25:1, or from about 10:1 to about 20:1.

[0431] The device portion can include a radiopaque material. For example, the filaments and / or struts of a stent, stent graft, or the first end portion, second end portion, intermediate portion, or sub-portion of a stent can include (e.g., be at least partially made from) titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, and combinations thereof. In another example case, the filaments and / or struts of a stent, stent graft, or a portion of a stent can include (e.g., be at least partially made from) a material having a density greater than about 9 grams per cubic centimeter. Separate radiopaque markers can be attached to some portions of the device. For example, the radiopaque markers can be added to the proximal end of the device or device portion (e.g., the proximal portion of the intermediate portion, the proximal portion of the distal portion), the distal end of the device or device portion (e.g., the distal portion of the intermediate portion, the distal portion of the proximal portion), and / or other portions. The radiopaque markers between the ends of the device can be useful, for example, to distinguish transition portions such as between materials, portions, etc. The radiopacity can vary along the length of the device. For example, the proximal portion can have a first radiopacity (e.g., due to the distal portion material and / or a separate marker), and the distal portion can have a second radiopacity different from the first radiopacity (e.g., due to the distal portion material and / or a separate marker). An expandable member such as a balloon can be filled with a radiopaque fluid. An expandable member such as a balloon can include a radiopaque marker coupled and / or integrated therewith (e.g., on the outer surface of the expandable member).

[0432] In some embodiments, the device has a polymeric tube and no support structure is provided. The intermediate portion of such a device can be made relatively more flexible than the end portions, for example, by reducing the wall thickness of the polymeric tube within the intermediate portion.

[0433] When a mesh or other support structure is provided in combination with a polymeric tube, the support structure can be positioned around the outside of the tube, within the lumen of the tube, or embedded within the wall of the tube. More than one support structure can be provided, and in that case, the respective support structures can be positioned differently with respect to the tube.

[0434] One or both of the end portions of the device can have retention elements such as hooks, projections, or returns configured to capture or grip the inner wall of a blood vessel. The radial force of the expanded end portion can be sufficient to capture or grip the inner wall of the blood vessel without using the retention elements.

[0435] There need not be a well-defined transition between the intermediate portion and the end portion. For example, the mesh type, material, thickness, flexibility, etc. can vary gradually from the end portion towards the intermediate portion or from the intermediate portion towards the end portion.

[0436] The flexibility of the device can increase gradually as it moves from the end portion towards the intermediate portion, as described, for example, with respect to devices 134, 140. The change in flexibility can be due to a change in mesh density (e.g., winding density, window size), tube thickness, or other factors. The flexibility of the device can be uniform or substantially uniform over the entire length of the support structure (e.g., stent) or over some portions of the support structure (e.g., over the entire end portion, over the entire intermediate portion, over one end portion and the intermediate portion but not the other end portion, etc.).

[0437] The devices described herein can be particularly suitable for use as transvascular shunts in percutaneous surgery and can be used for many other medical applications. For example, the devices can be used for the treatment of occluded blood vessels having a tortuous or angulated path or for angioplasty where the blood vessel may be subject to bending or deformation at or near the location of the stent. The stent can also be used, for example, in aortic graft procedures or for the repair of damaged blood vessels after puncture during percutaneous procedures. In some such cases, the intermediate portion of the device can enable the device to conform to the shape of the blood vessel and deform in response to the movement of the blood vessel, while the end portions are fixed or retained in place, reducing the risk of fatigue failure. In another example case, the device can be used to form a shunt for dialysis access and / or access for drug administration (e.g., intermittent injection for cancer treatment which may damage the blood vessel) between a healthy artery and a healthy vein.

[0438] Referring again to FIGS. 4 and 7, the block material 251 can help prevent or impede retrograde arterial blood flow. As will be described in more detail herein, additional methods and systems or other methods and systems can be used to prevent or impede retrograde arterial blood flow, that is, in other words, to prevent or impede the flow of arterial blood flowing into the vein from flowing in the normal pre-treatment direction of blood flow within the vein, thereby bypassing oxygenated blood downstream of tissues such as the foot.

[0439] Without treatment, peripheral vascular disease (PVD) can progress to critical limb ischemia (CLI), which is characterized by severe chronic pain and extensive tissue loss, which limits the options for revascularization and often leads to amputation. CLI is estimated to have an incidence of about 50 - 100 cases per 100,000 per year and is associated with a mortality rate of 20% within 6 months of onset.

[0440] Interventional radiologists have actively attempted to treat CLI by bypassing the CTO within the subintimal space using products such as the Medtronic Pioneer catheter, either by attempting to fully open a chronic total occlusion (CTO) or by passing a wire within the subintimal space adjacent to the CTO and then attempting to re-enter the vessel distal to the occlusion. Once the wire is in place, the user can optionally create a wider channel and then place a stent to result in a bypass conduit that traverses the occlusion. Conventional approaches such as percutaneous transluminal angioplasty (PTA), stenting, and drug-eluting balloons (DEB) for treating PAD can be used for CLI treatment additionally or alternatively when the wire can cross the occlusion.

[0441] According to the website of amputee-calition.org, some statistics regarding the problem of CLT are as follows: There are nearly 2 million amputees in the United States of America. Among the amputees, the main causes are as follows: Vascular diseases (54%) (diabetes and peripheral artery disease (PAD)), Trauma (45%), and Cancer (less than 2%). Approximately 185,000 amputations are performed each year in the United States of America. The hospitalization costs associated with amputation exceeded a total of $6.5 billion in 2007. The survival rates after amputation vary based on various factors. Those who have undergone amputation due to vascular diseases (including PAD and diabetes) have been reported to have a 30-day mortality rate of 9% - 15%, and the long-term survival rates are 60% at 1 year, 42% at 3 years, and 35% - 45% at 5 years. Nearly half of those who have lost a limb due to dysvascular disease die within 5 years. This is higher than the 5-year mortality rate suffered by those with colorectal cancer, breast cancer, and prostate cancer. Among those with diabetes who have undergone lower limb amputation, up to 55% may require amputation of the other leg within 2 - 3 years.

[0442] CLIs have been surgically treated by venous arterialization of the open limb since the early 1900s. A small series of clinical trials using open limb surgical approaches, such as those outlined in the 2006 meta-analysis paper titled "Meta-analysis of the clinical effectiveness of venous arterialization for salvage of critically ischemic limbs" by Lu et al. (European Journal of Vascular and Endovascular Surgery, vol. 31, pp. 493-499), have been published over the years. The above paper has reached the following results and conclusions: Results: A total of 56 trials were selected for comprehensive review. There were no identified randomized controlled trials (RCTs). Seven patient groups including 228 patients met the selection criteria. The overall limb salvage at 1 year was 71% (95% CI: 64% - 77%), and the secondary patency rate at 1 year was 46% (95% CI: 39% - 53%). Most of the patients who avoided major amputation healed their wounds successfully, had no rest pain, and had no serious complications. Conclusions: Based on limited evidence, venous arterialization can be considered a viable alternative before performing major amputation on patients with "non-operable" chronic severe ischemic limbs.

[0443] Among other diseases described herein, the methods and systems described herein can create a fistula between an artery and a vein (AV) within the below-the-knee (BKT) vasculature using an endovascular minimally invasive approach. Such methods may be suitable for patients who (i) have a clinical diagnosis of symptomatic severe limb ischemia as defined by Rutherford 5 or 6 (severe ischemic ulcer or overt gangrene), (ii) are evaluated by a vascular surgeon and an interventionist and determined to be not amenable to surgical or endovascular treatment, and / or (iii) have a clear benefit from major amputation.

[0444] In some embodiments, the system or kit optionally includes one or more of the following components: a first ultrasonic catheter (e.g., an arterial catheter, an emitting catheter having a needle, etc.), a second ultrasonic 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 7Fr (approximately 2.3 mm) delivery system)). The system or kit optionally further includes an ultrasonic system, a control system (e.g., a computer). Some users may already have a suitable ultrasonic system that can be connected to the ultrasonic catheter(s). The catheters and prostheses described above can be used in the system or kit, and details of other, additional, and / or modified, possible components will be described below.

[0445] FIG. 14A is a schematic side cross-sectional view of an exemplary embodiment of an ultrasonic emission catheter 170 having a needle 172 (e.g., a first ultrasonic catheter, an arterial catheter (e.g., when extending a needle from an artery into a vein), a venous catheter (e.g., when extending a needle from a vein into an artery)). The catheter 170 is disposed within an artery with the needle 172 retracted inside the lumen of the catheter 170. The catheter 170 can track over a guide wire (e.g., a 0.014-inch (approximately 0.36 mm) guide wire) and / or be placed through a sheath within an artery (e.g., the femoral artery) and advanced to a total occlusion site in the artery (in the tibial artery). The catheter 170 has a handle 174 having a pusher ring 176. By advancing the pusher ring 176 longitudinally or distally, the needle 172 can advance out of the lumen of the catheter 170 into the vein as described herein. Other mechanisms for advancing the needle 172 are also conceivable (e.g., rotary, electric, etc.). Before, after, and / or while advancing the needle, a guide wire (e.g., a 0.014-inch (approximately 0.36 mm) guide wire) can be placed through the needle 172 (as described with respect to the guide wire 14 of FIG. 3), which can be referred to as a crossing wire.

[0446] FIG. 14B is an enlarged schematic side cross-sectional view of the distal portion of the ultrasonic emission catheter 170 within circle 14B of FIG. 14A. When advanced or launched, the needle 172 extends radially outward from the lumen 173 of the catheter 170. In some embodiments, the lumen 173 terminates proximate to an ultrasonic transmitter 178. The needle 172 can extend along a path that aligns with (e.g., is parallel to) the path of the directed ultrasonic signal transmitted by the ultrasonic transmitter 178. FIG. 14B also shows a lumen 175 that can be used to accommodate a guide wire for tracking the catheter 170 to a desired location.

[0447] FIG. 15A is a schematic side view of an exemplary embodiment of an ultrasonic target catheter 180 (e.g., a second ultrasonic catheter, an arterial catheter (e.g., when extending a needle from a vein into an artery), a venous catheter (e.g., when extending a needle from an artery into a vein)). FIG. 15B is an enlarged schematic side cross-sectional view of the ultrasonic target catheter 180 within circle 15B of FIG. 15A. FIG. 15C is an enlarged schematic side cross-sectional view of the ultrasonic target catheter 180 within circle 15C of FIG. 15A. The catheter 180 can track on a guide wire (e.g., a 0.014-inch (about 0.36 mm) guide wire) and / or be placed through a sheath into a vein (e.g., the femoral vein) and advanced to a point proximal to and / or parallel to the distal end of the catheter 170 (e.g., at the tibial artery) and / or to an occlusion within an artery. The catheter 180 has an ultrasonic receiving transducer 182 (e.g., an omnidirectional ultrasonic receiving transducer) that can act as a target in the vein to align the needle 172 of the catheter 170. The catheter 180 can be left in place or can be made stationary or substantially stationary, while the catheter 170 rotates and moves longitudinally to obtain a good or optimal ultrasonic signal indicating that the needle 172 is aligned with the catheter 180 and in the direction of the catheter 180.

[0448] Catheters 170 and 180 may be connected to a computer-executed transceiver software and to an ultrasonic transceiver controlled by the computer-executed transceiver software. As described in more detail herein, catheter 170 has a flat ultrasonic transmitter 178 or a directional ultrasonic transmitter 178 configured to transmit an ultrasonic signal having a small angular spread or a tight beam (e.g., a small beam width) in the direction of the path of needle 172 when advancing from lumen 173 of catheter 170. Catheter 180 has an omnidirectional (360-degree) ultrasonic receiver 182 configured to act as a target for the ultrasonic signal transmitted by directional transmitter 178 of catheter 170. Catheter 170 rotates until a peak ultrasonic signal indicating that needle 172 is aligned with catheter 180 is displayed such that when needle 172 extends (e.g., by advancing ring 176 of handle 174 longitudinally), needle 172 can exit the artery in which catheter 170 is located, pass through interstitial tissue, and proceed into the vein in which catheter 180 is located.

[0449] FIG. 16 is an exemplary embodiment of a graph for detecting catheter alignment that can be displayed on a display device (e.g., a laptop, tablet computer, smartphone, combination thereof, etc.) of an ultrasonic system. The graph in FIG. 16 shows that a signal transmitted from a transmitting catheter within a vein is being received by a receiving catheter within the vein. The second frequency envelope on the right side 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 within the artery in both the rotational and longitudinal directions, for example, until the second envelope is maximized, which indicates that the catheters are accurately oriented.

[0450] FIG. 17 is a schematic side elevation view of an exemplary embodiment of a prosthesis (e.g., a stent, a stent graft) delivery system 190. In some embodiments, the delivery system 190 is a 7Fr (approximately 2.3 mm) delivery system. FIG. 18 is a schematic side elevation view of an exemplary embodiment of a prosthesis (e.g., a stent, a stent graft) 200. In FIG. 17, the prosthesis (e.g., prosthesis 200, other prostheses described herein, etc.) is in a compressed or crimped state proximate to the distal end 192 of the delivery system 190. In some embodiments, the prosthesis 200 includes a shape memory stent covered by a graft material as described above, for example. When the crossover wire extends from the artery to the vein, as described herein, for example, as a result of advancing through the needle 172, the delivery system 190 can advance over the crossover wire. The prosthesis 200 can be deployed from the delivery system 190, for example, by grasping the trigger handle 194 of the delivery system 190 and retracting the prosthesis 200 proximally and / or advancing it distally into the outer cover sheath. The prosthesis 200 can create a flow path through the interstitial tissue between the artery and the vein. Other types of delivery systems and prostheses are also contemplated.

[0451] Referring again to FIG. 17, some non-limiting exemplary dimensions of the delivery system 190 are presented. The travel distance 196 of the trigger handle 194 can be, for example, from about 0.4 inches (approximately 1 cm) to about 12 inches (approximately 30 cm), from about 1 inch (approximately 2.5 cm) to about 8 inches (approximately 20 mm), or from about 2 inches (approximately 5 cm) to about 6 inches (approximately 15 mm) (e.g., about 2 inches (approximately 5 cm)). In some embodiments, the travel distance 196 of the trigger handle 194 is at least as long as the length of the prosthesis 200 that is deployed (e.g., in a radially expanded state). In some embodiments, a transmission or other mechanism may be used to shorten the travel distance 196 of the trigger handle 194 to less than the length of the prosthesis 200 that is deployed (e.g., in a radially expanded state). The distance 196 can be adjusted based on, for example, at least one of the length of the prosthesis 200 that is deployed, the degree to which the deployed prosthesis 200 is collapsed, the deployment mechanism (e.g., whether the outer sheath is retracted proximally, the prosthesis 200 is pushed distally forward, or both are done, whether the delivery system 190 includes a transmission mechanism, etc.), combinations thereof, and the like. The length 197 of the outer sheath or catheter portion can be, for example, from about 40 inches (approximately 1020 mm) to about 50 inches (approximately 1270 mm), from about 46 inches (approximately 1170 mm) to about 47 inches (approximately 1190 mm), or from about 46.48 inches (approximately 1180 mm) to about 46.7 inches (approximately 1186 mm). The overall length 198 of the delivery system 190 from the proximal tip to the distal tip can be, for example, from about 40 inches (approximately 1000 mm) to about 60 inches (approximately 1500 mm). The lengths 197 and 198 can be adjusted based on, for example, at least one of the length of the prosthesis 200 that is deployed, the degree to which the deployed prosthesis 200 is collapsed, the patient's height, the location of the occlusion being treated, combinations thereof, and the like. In some embodiments, it is advantageous that handling or management by the user can be made easier, for example, by separating the trigger handle 194 from the vascular access point by about 10 cm to about 30 cm (e.g., at least about 20 cm).In some such embodiments, the length 197 may be from about 120 cm to about 130 cm (e.g., in the case of an anterograde approach) or from about 150 cm to about 180 cm (e.g., in the case of a contralateral approach).

[0452] Referring again to FIG. 18, some non-limiting exemplary dimensions of the prosthesis 200 are presented, at least in accordance with the compressed state. The thickness 201 of the structural strut can be, for example, from about 0.05 mm to about 0.5 mm or from about 0.1 mm to about 0.2 mm (e.g., about 0.143 mm). The spacing 202 between the struts of the structural strut can be, for example, from about 0.005 mm to about 0.05 mm or from about 0.01 mm to about 0.03 mm (e.g., about 0.025 mm). The thickness 203 of the connecting strut can be, for example, from about 0.05 mm to about 0.5 mm or from about 0.1 mm to about 0.2 mm (e.g., about 0.133 mm). The longitudinal length 204 of the structural component can be, for example, from about 1 mm to about 5 mm or from about 2.5 mm to about 3 mm (e.g., about 2.8 mm). The longitudinal length 205 between the structural components can be, for example, from about 0.25 mm to about 1 mm or from about 0.5 mm to about 0.6 mm (e.g., about 0.565 mm). The length 206 of the struts within the structural component, including all portions wound back and forth, can be, for example, from about 25 mm to about 100 mm or from about 65 mm to about 70 mm (e.g., about 67.62 mm). The overall longitudinal length of the prosthesis 200 can be, for example, from about 25 mm to about 150 mm or from about 50 mm to about 70 mm (e.g., about 62 mm). As described herein, a wide variety of laser cut stents, woven stents, and combinations thereof, including various dimensions, are also contemplated. The struts described herein can include portions that are not cut from wire or filament, or hypotube or sheet.

[0453] The proximal end and / or distal end of the prosthesis 200 may optionally have a ring 210. The ring 210 can, for example, assist in placing the prosthesis 200 within an artery and / or vein. The circumferential width 211 of the ring 210 can be, for example, from about 0.25 mm to about 1 mm or from about 0.5 mm to about 0.75 mm (e.g., 0.63 mm). The longitudinal length 212 of the ring 210 can be, for example, from about 0.25 mm to about 2 mm or from about 0.5 mm to about 1 mm (e.g., 0.785 mm). In some embodiments, the ratio of the overall length of the prosthesis 200 to the longitudinal length 212 of the ring 210 can be from about 50:1 to about 100:1 (e.g., about 79:1). The dimensions 211, 212 of the ring 210 can be adjusted, for example, based on at least one of strut thickness, the diameter of the prosthesis (e.g., relative to a blood vessel), the overall length of the prosthesis, material, shape setting characteristics, combinations thereof, and the like.

[0454] FIG. 19 is a schematic side elevation view of a prosthesis 220 in another exemplary embodiment. The prosthesis 200 can have, for example, the shape of the prosthesis 220 in a radially expanded state (e.g., when deployed from the delivery system 190). FIG. 19 shows an exemplary shape of a prosthesis 220 having a first portion 221 and a second portion 225. The first portion 221 has a substantially cylindrical or cylindrical shape having a length 222 of from about 15 mm to about 25 mm (e.g., about 21 mm) and a diameter 223 of from about 2.5 mm to about 5 mm (e.g., about 3.5 mm). The second portion 225 has a substantially frustoconical or frustoconical shape having a length 226 of from about 30 mm to about 50 mm (e.g., about 41 mm) and a widest diameter 227 of from about 4 mm to about 10 mm, from about 4 mm to about 7 mm (e.g., about 5.5 mm), etc. The taper angle of the second portion 225 away from the first portion 221 can be from about 0.02 degrees to about 0.03 degrees (e.g., about 0.024 degrees).

[0455] Further details regarding prostheses that can be used in accordance with the methods and systems described herein are set forth in U.S. Patent Application No. 13 / 791,185, filed March 8, 2013, which is hereby incorporated by reference in its entirety.

[0456] Figures 20A - 20H schematically illustrate exemplary embodiments of a method for performing retrograde perfusion. This method is described with respect to the peripheral vasculature such as the lower extremities, but can also be adapted as needed for other body cavities (e.g., the heart, other peripheries, etc.). Some steps such as anesthesia, incision and suturing at specific sites are clear and can be omitted. In some embodiments, the method can be performed from a vein to an artery (e.g., by the venous catheter described below).

[0457] Access to the femoral artery and femoral vein is obtained. For example, using the Seldinger technique, an introducer sheath (e.g., 7Fr (approximately 2.3 mm)) is inserted into the femoral artery and an introducer sheath (e.g., 6Fr (approximately 2 mm)) is inserted into the femoral vein. A guidewire (e.g., 0.014 inches (approximately 0.36 mm), 0.035 inches (approximately 0.89 mm), 0.038 inches (approximately 0.97 mm)) is inserted through the introducer sheath in the femoral artery and guided into the distal portion of the posterior tibial artery or anterior tibial artery 300 of the affected area. A second guidewire (e.g., 0.014 inches (approximately 0.36 mm), 0.035 inches (approximately 0.89 mm), 0.038 inches (approximately 0.97 mm)) or a snare is inserted through the introducer sheath in the femoral artery. In embodiments where a snare is used, the third guidewire, fourth guidewire, etc. described herein are accurate even if the numbering is not sequential.

[0458] A venous access needle is percutaneously inserted into a target vein, such as the tibial vein (e.g., the proximal tibial vein (PTV)). In some embodiments, the venous access needle may be guided under ultrasound. In some embodiments, a contrast agent is injected into the superficial vein on the foot side (retrograde), and then flowed into the PTV. This flow path can be captured using fluoroscopy so that the venous access needle can be guided by fluoroscopy instead of or in addition to ultrasound.

[0459] The target vein can be accessed proximally and distally (e.g., several inches or centimeters) below the location where the delivery catheter 310 is to be placed. In some embodiments, the target vein may be within the ankle. When the venous access needle is in the vein, a third guidewire (or the "second" guidewire if a snare is used instead of the second guidewire) is inserted into the venous access needle and advanced anterogradely in the target vein to the femoral vein. This access method is advantageously capable of reducing problems resulting from advancing the wire retrograde across a venous valve, which is described in detail below. The third guidewire is snared, for example, using a fluoroscopic guide and passed through the femoral vein sheath. The target catheter 320 is inserted into the femoral vein sheath through the snared third guidewire. As shown in FIG. 20A, the target catheter is advanced within the venous system over the third guidewire until the target catheter is proximal to and / or parallel to the guidewire and / or proximal to the occlusion 304 at the distal portion of the posterior tibial artery or anterior tibial artery of the affected area.

[0460] In some embodiments, the third guide wire may have an ultrasonic receiving transducer (e.g., omnidirectional) attached to provide a target for the signal transmitted by the launch catheter 310, or the target catheter 320 can be tracked over the third guide wire, either of which may obviate some techniques (e.g., femoral vein access, introduction of a venous introducer sheath, insertion of a second guide wire, antegrade advancement of the third guide wire to the femoral vein, snaring of the third guide wire, advancement of the target catheter 320 over the third guide wire).

[0461] In some embodiments, for example, direct access to the PTV using ultrasound may be possible, which may enable the target catheter 320 to be placed directly into the PTV using, for example, a small sheath, thereby obviating some techniques (e.g., femoral vein access, introduction of a venous introducer sheath, insertion of a second guide wire, antegrade advancement of the third guide wire to the femoral vein).

[0462] In some embodiments, the catheter 320 is not an over-the-wire catheter but includes a guide wire and an ultrasonic receiving transducer (e.g., omnidirectional). The catheter 320 can be inserted as the third guide wire, the second guide wire, or as a guide wire passing through a small sheath when accessing the PTV directly, as described above.

[0463] An ultrasonic transducer generally has two electrodes that can vibrate and have surfaces separated by ceramic. The incoming or received ultrasonic signal waveforms combine to form a length extension mode as shown in FIG. 21. FIG. 21 is a schematic perspective view of an exemplary embodiment of an ultrasonic receiving transducer 350. The proximal end or upper end 352 of the transducer 350 and the distal end or lower end 354 of the transducer are conductive, and when electrically connected to a wire, the transducer can receive ultrasonic signals. In some embodiments, the transducer 350 has a length 356 of about 0.1 mm to about 0.4 mm (e.g., about 0.25 mm). In some embodiments, the transducer 350 has an overlapping length 358 of about 0.1 mm to about 0.3 mm (e.g., about 0.2 mm). In some embodiments, the transducer 350 has a diameter that is the same as, substantially the same as, or the same as the guide wire to which the transducer 350 is attached. In some embodiments, the signal receiving ability of the transducer 350 may be enhanced by an array or a series of laminated plates.

[0464] In some embodiments, a guide wire having an ultrasonic receiving transducer can have a piezoelectric film (e.g., including plastic), thereby enhancing the signal receiving ability of the transducer. FIG. 22 is a schematic cross-sectional view of another exemplary embodiment of an ultrasonic receiving transducer 360. The ultrasonic receiving transducer 360 shown in FIG. 22 has an optional lumen 368. The ultrasonic receiving transducer 360 has a series of layers 362, 364, 366. Layer 362 may include a polymer (e.g., polyvinylidene fluoride (PVDF)) layer. Layer 364 may include an inorganic compound (e.g., tungsten carbide) layer. Layer 366 may include a polymer (e.g., polyimide) layer. Layer 366 may have a thickness of about 25 micrometers (μm or micron) to about 250 μm (e.g., at least about 50 μm).

[0465] As shown in FIG. 20B, the emission catheter 310 tracks on a guide wire within the femoral artery and the tibial artery proximal to the occlusion 304, proximate to the occlusion 304. The catheter 310 may be more proximal to the occlusion 304 depending on the suitability of the anatomical structure of that portion of the retrograde perfusion process. In some embodiments, the catheter 310 may be positioned in the distal portion of the posterior tibial artery or the 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.

[0466] The emission catheter 310 transmits a directional ultrasonic signal. As indicated by the arrows 311, 312 in FIG. 20C, the emission catheter 310 rotates and moves longitudinally until the signal is received by the target catheter 320. When the signal is received, this indicates alignment, whereby a needle extends from the emission catheter 310, enabling successful access to the vein. As shown in FIG. 20D, the crossing needle 314 advances from the catheter 310 and enters the tibial vein 302 from the tibial artery 300. The accuracy of positioning the crossing needle 314 to form a fistula between the artery 300 and the vein 302 can be confirmed, for example, using contrast agents and fluoroscopy.

[0467] In some embodiments, the ultrasonic signal can be used to determine the distance between the artery 300 and the vein 302. Referring again to FIG. 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 the distance between the catheters.

[0468] Referring again to FIG. 16, the display device can graphically show the signal alignment peak to enable the user to determine the alignment position. In some embodiments, the signal alignment can change the color, for example, from red to green when it exceeds or is less than a threshold value. In some embodiments, for example, when the alignment signal exceeds the threshold, an audible signal can be transmitted, thereby enabling the user to continue to focus on the patient rather than monitoring the screen substantially continuously.

[0469] In some embodiments, the horizontal line on the screen can move to show the maximum signal, i.e., the peak, achieved up to that point during the procedure. This line can be called "peak hold". When a larger signal value is achieved, the horizontal line moves to coincide with that higher value. If the peak cannot be pulled up beyond the horizontal line by operation, it may indicate the maximum alignment. When the signal peak drops below the horizontal line by a certain amount, the catheter is moving and the catheter can no longer be properly aligned. Since the alignment level indicated by the horizontal line has been achieved in advance during the procedure, the user can see that such an alignment level can be achieved by further rotational and / or longitudinal operations.

[0470] Place a fourth guidewire 316 (e.g., 0.014 inches (approximately 0.36 mm)) (or the "third" guidewire if a snare is used instead of the second guidewire) into the tibial vein 302 in a retrograde direction (of the vein 302) through the lumen of the crossing needle 314 of the catheter 310 as shown in FIG. 20E. Apply an outer cuff pressure from above the needle intersection to reduce the flow in the artery 300 to prevent or inhibit the formation of a hematoma and / or to distend the vein to facilitate crossing of the valve. Leave the guidewire 316 in place and move the catheters 310, 320, which can extend from an introducer sheath in the femoral artery and pass through the arterial tree into the tibial vein 302.

[0471] Instead of or in addition to the directional ultrasound technique described herein, some techniques for crossing guide wire 316 from artery 300 to vein 302 may be used.

[0472] In some embodiments, a tourniquet can be applied to the leg, thereby increasing the vein diameter. In some embodiments, a blocking material (e.g., a blocking balloon as described with respect to FIGS. 4 and 7) may be used to increase the vein diameter. For example, the vein can be expanded by stagnation of venous flow. The larger vein diameter can make the target of the crossing needle 314 larger, and the vein 300 can be more easily accessed by the crossing needle 314.

[0473] In some embodiments, a PTA balloon can be used within 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 proper alignment of the crossing needle 314 can be confirmed by the pressure drop of the PTA balloon. The PTA balloon can make the target of the crossing needle 314 larger by increasing the vein diameter, and the vein 300 can be more easily accessed by the crossing needle 314. The guide wire 316 can advance through the crossing needle 314 to the PTA balloon.

[0474] In some embodiments, the PTA balloon has a mesh (e.g., a woven mesh) embedded within the polymer of the balloon, for example. When a balloon without such a mesh is punctured, the balloon material may rupture and cause an embolism (e.g., fragments of the balloon are washed downstream). The mesh can help prevent tearing of the balloon material, thereby preventing or precluding the balloon material from causing an embolism. In some embodiments, a meshless balloon can be configured to snare a guidewire when folded, whether or not it is punctured (e.g., by entangling the guidewire in a fold of the balloon).

[0475] In some embodiments, two PTA balloons longitudinally spaced along the axis of the catheter can be used within the target vein, and the needle catheter can target one of the PTA balloons. When one of the PTA balloons is punctured by the crossing needle 314, the punctured PTA balloon no longer serves as a barrier for the contrast agent, so the contrast agent within the well between the balloons can be released. The release of the contrast agent can be monitored using fluoroscopy. The PTA balloons can be on the same catheter side or on different catheter sides.

[0476] In some embodiments, two PTA balloons longitudinally spaced along the axis of the catheter can be used within the target vein, and the needle catheter can target the space or well between the PTA balloons. When the well is punctured by the crossing needle 314, the contrast agent within the well can be disturbed. The disturbance of the contrast agent can be monitored using fluoroscopy. The PTA balloons can be on the same catheter side or on different catheter sides.

[0477] In some embodiments where a PTA balloon can be used in combination with an ultrasonic target within a target vein, a PA balloon catheter has a PTA balloon and an ultrasonic receiving transducer (e.g., omnidirectional). In some such embodiments, the firing catheter 310 can target the PTA balloon under fluoroscopy, as described herein, and / or can target the ultrasonic receiving transducer. The crossover needle 314 can puncture the PTA balloon, and the proper alignment of the crossover needle 314 can be confirmed by the pressure drop of the PTA balloon. The ability of the PTA balloon to increase the vein diameter makes the target of the crossover needle 314 larger, and the vein 300 is more easily accessed by the crossover needle 314. The guidewire 316 can advance through the crossover needle 314 to the PTA balloon.

[0478] In some embodiments, a LeMaitre device (e.g., the UnBalloon™ Non - Occlusive Modeling Catheter available from LeMaitre Vascular, Inc., of Burlington, Massachusetts) can be used within the target vein. In some embodiments, the LeMaitre device can increase the vein diameter. A larger vein diameter can make the target for the crossing needle 314 larger, and the vein 300 is more accessible by the crossing needle 314. In some embodiments, the needle 314 can penetrate the LeMaitre device. In some such embodiments, the LeMaitre device can serve as a mesh target (e.g., including a radiopaque material visible under fluoroscopy) for the crossing needle 314. The mesh of the LeMaitre device can be radially expanded by advancing the proximal portion of the mesh distally and / or by retracting the distal portion of the mesh proximally (e.g., pushing both ends together like an umbrella) and / or by enabling the mesh to self - expand (e.g., in embodiments where at least a portion of the mesh includes a shape - memory material). In some embodiments, when closing, the LeMaitre device can grip the crossing wire to hold it within the target vein.

[0479] In some embodiments, the launch catheter 310 can comprise a first magnet having a first polarity, and the target catheter 320 can comprise a second magnet having a second polarity. When the magnets are close enough to the magnetic force that moves one or both of the catheters 310, 320, the crossing catheter 314 can be advanced to create a fistula between the artery 300 and the vein 302. In some embodiments, the first magnet can be circumferentially aligned with the crossing needle 314, and / or the launch catheter 310 can be magnetically shielded to perform alignment by rotation. In some embodiments, the second magnet can be relatively thin in the longitudinal direction to perform longitudinal alignment. In some embodiments, the crossing needle 314 and / or the guide wire 316 can be magnetically pulled from the artery 300 to the vein 302, or vice versa from the vein 302 to the artery 300. Some systems can have both an ultrasonic guide and a magnetic guide. For example, the ultrasonic guide can be used for initial alignment, and the magnetic guide can be used for precise alignment.

[0480] Referring again to FIGS. 20A - 20H, as shown in FIG. 20F, a prosthesis delivery system 330 carrying a prosthesis 349 tracks over the guide wire 316 through the gap space between the artery 300 and the vein 302. In some embodiments, prior to introducing the prosthesis delivery system 330, a separate PTA balloon catheter (e.g., about 2 mm) can be tracked over the guide wire 316 to pre - dilate the fistula between the artery 300 and the vein 302. The use of the PTA balloon catheter can be determined, for example, according to the radial force of the prosthesis 340.

[0481] The prosthesis 340 is deployed from the prosthesis delivery system 330, for example, by operating the trigger handle 194 (FIG. 17). In some embodiments, if the prosthesis 340 cannot be expanded and / or advanced, for example, the prosthesis delivery system 330 can be removed and a PTA catheter (e.g., about 2 mm) can be advanced over the guidewire 316 to attempt to dilate or further dilate the fistula between the artery 300 and the vein 302. Thereafter, deployment of the prosthesis 340 can be attempted again (e.g., by self-expansion, balloon expansion, etc.). In some embodiments, deployment of the prosthesis 340 can remodel the blood vessel to expand the diameter of the blood vessel by at least about 10%, at least about 20%, at least about 30% or more, about 0% to about 10%, about 0% to about 20%, about 0% to about 30% or more. In embodiments where the prosthesis 340 is self-expanding, the degree of remodeling can change over time. For example, the prosthesis 340 expands as the blood vessel expands and contracts as the blood vessel contracts.

[0482] As shown in FIG. 20G, when the prosthesis 340 is deployed, the fistula can be enlarged by a PTA catheter. The diameter of the PTA catheter (e.g., from about 3 mm to about 6 mm) can 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) useful for one, more, or all of the optional PTA balloon catheter techniques described herein. In embodiments where the prosthesis has a conical portion, the PTA balloon can have a conical portion. Once the prosthesis 340 is in place, the prosthesis delivery system 330 can be removed, as shown in FIG. 20H. Thereby, an AV fistula is formed between the artery 300 and the vein 302. Confirmation of the placement of the venous catheters 310, 320, 330 and the prosthesis 340 can be confirmed through part or all of the procedure under fluoroscopy using contrast agent injection.

[0483] In some embodiments, a marker (e.g., a clip, a lancet, forceps, a pencil, etc.) can be applied to the skin (e.g., adhered, placed on top, etc.) to generally mark the location of the fistula formed between the artery 300 and the vein 302 by the crossing needle 314 before deploying the prosthesis 340. In embodiments where the user uses a sphygmomanometer that inflates over the fistula to avoid bleeding, the lack of blood flow can make it difficult to visualize or even evaluate the fistula site, but such identification can be made by the marker. In embodiments where the transmit catheter / receive catheter is removed after fistula formation, the intersection may be difficult for the user to sense or judge, but such identification can be made by the marker. When the fistula is enlarged, it is preferable that the midpoint of the dilation balloon can be aligned with the midpoint of the fistula (e.g., to increase or maximize the interstitial space through-hole). In some embodiments, the marker can be visualized under fluoroscopy (e.g., including radiopaque line material) to enable the user to confirm and remember the location of the fistula under fluoroscopy before deploying the prosthesis 340.

[0484] Once the prosthesis 340 is in place, an obstacle to the blood flowing through the vein 302 to the foot is the valve within the vein. Manipulating a guidewire across the venous valve can be difficult, for example, because the pressure from the artery may be insufficient to dilate the vein and render the valve non-functional. As will be described in more detail below, it has been found that one or more of a variety of techniques, such as PTA catheters, stents (e.g., covered stents, stent grafts, etc.), and valvulotomy knives, can be used to incapacitate or render non-functional the venous valve distal to the AV fistula. By incapacitating the venous valve, it becomes possible to flow blood to the distal part of the venous circulation of the foot through retrograde perfusion from the femoral artery, retrograde flow within the vein 302, and retrograde flow within the vein into the venules and capillaries to supply oxygenated blood to the foot in CLI patients.

[0485] In some embodiments, a high-pressure PTA balloon catheter can be used to inactivate venous valves (e.g., when inflated to exceed about 10 atm (approximately 1013 kilopascals (kPa))).

[0486] In some embodiments, one or more stents can be placed across one or more venous valves to inactivate those valves. For example, such a stent should have a radial force sufficient to keep the valve open. The stent can forcibly tear the valve. In some embodiments, the stent comprises a coating or a graft. Certain such embodiments can cover venous collateral vessels. In some embodiments, the stent is bare, i.e., does not comprise a coating or a graft. Certain such embodiments can reduce costs. The venous stent can extend along a length of the vein (e.g., the entire length). For example, in some embodiments, the entire length of the PTV is lined with a covered stent that covers the venous collateral vessels and tears the venous valve.

[0487] In some embodiments, the venous stent is separate from the fistula prosthesis. A separate venous stent can allow for greater flexibility with respect to characteristics such as dimensions (e.g., length, diameter), materials (e.g., with or without a coating or graft), and other characteristics. FIG. 31A schematically shows an exemplary embodiment of an arteriovenous fistula stent 340 separate from an exemplary embodiment of a venous stent 342. The venous stent 342 is spaced from the fistula stent 340 (e.g., as shown in FIG. 31A), and may abut, overlap, be nested, or be coaxial with the fistula stent 340 (e.g., the distal segment of the fistula stent 340 is at least partially inside the proximal segment of the venous stent 342, or the proximal segment of the venous stent 342 is at least partially inside the distal segment of the fistula stent 340). In an embodiment where the fistula stent 340 and the venous stent 342 overlap, first, due to the placement of the venous stent 342, the proximal end of the venous stent 342 facing the direction of retrograde blood flow is covered by the fistula stent 340, and blood flow interruption that may occur at the distal end of the venous stent 342 can be reduced or eliminated. In an embodiment where the fistula stent 340 and the venous stent 342 overlap, next, the venous stent 342 can be placed through the fistula stent 340 such that the two stents 340, 342 can share at least one deployment parameter (e.g., by tracking a stent deployment device on the same guide wire). The venous stent 342 can be deployed before or after the fistula stent 340. The venous stent 342 can have a length of about 2 cm to 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.).

[0488] In some embodiments, the venous stent is integral with the fistula prosthesis. The integrated venous stent can allow for further flexibility with respect to characteristics such as dimensions (e.g., length, diameter), materials (e.g., with or without a coating material or graft), and other characteristics. FIG. 31B schematically shows an exemplary embodiment of an arteriovenous fistula stent 344 with an integrated venous stent. FIG. 31C schema...

Claims

1. 1. An apparatus for diverting blood flow from a first blood vessel to a second blood vessel and maintaining blood flow in the first blood vessel, comprising: A stent structure extending along the length from the proximal end to the distal end and embedded within the graft. Equipped with The stent structure comprises: a first segment extending from the proximal end and configured to be anchored to the first blood vessel, a window, allowing a first portion of blood flow to flow through the window into the first segment and out of the first segment distally into the first vessel, thereby maintaining blood flow in the first vessel. The first segment; a second segment extending from the distal end and configured to be disposed within the second blood vessel, the second segment is configured to receive a second portion of the blood flow from the first segment and direct the second portion of the blood flow through the second segment distally out of the distal end into the second blood vessel. the second segment; a third segment disposed between the first segment and the second segment, when the stent structure is in an expanded state, the third segment has a tapered diameter that expands to a diameter of the second segment. the third segment; Including, Device.

2. the second segment comprises a graft covering; 2. The apparatus of claim 1.

3. the first segment includes a flange; 3. Apparatus according to claim 1 or 2.

4. the first segment has a first diameter and is configured to overlap a stent graft to stretch the vessel, and the second segment tapers from the first diameter to a second diameter, such that the device is configured to stretch the vessel in a tapered manner to provide laminar blood flow through the device.

4. Apparatus according to any one of claims 1 to 3.

5. 1. An apparatus for diverting blood flow from a first blood vessel to a second blood vessel and maintaining blood flow in the first blood vessel, comprising: A stent structure extending along its length from the proximal end to the distal end and embedded within the graft. Equipped with The stent structure comprises: a first segment extending from the proximal end and configured to be anchored to the first blood vessel, a fenestration that allows blood to flow into the first segment and through the fenestration to a distal portion of the first vessel; Including, The first segment; a second segment extending from the distal end and configured to be disposed within the second blood vessel and configured to allow blood to flow into the first segment, through the second segment, and into the second blood vessel; the second segment; a third segment disposed between the first segment and the second segment, when the stent structure is in an expanded state, the third segment has a tapered diameter that expands to a diameter of the second segment. the third segment; Including, Device.

6. the first segment includes a flap configured to open radially outward; 6. Apparatus according to any one of claims 1 to 5.

7. the first segment is deployable separately from the second segment; 7. Apparatus according to any one of claims 1 to 6.

8. the first segment comprises a bifurcation configured to be disposed within a branch vessel of the first vessel.

8. Apparatus according to any one of claims 1 to 7.

9. the first segment includes a plurality of slits configured to open upon bending of the first segment; 9. Apparatus according to any one of claims 1 to 8.

10. At least a portion of the stent structure is uncovered.

10. Apparatus according to any one of claims 1 to 9.

11. the first segment comprises a graft covering; 11. Apparatus according to any one of claims 1 to 10.

12. The first segment or the second segment is at least partially cylindrical.

12. Apparatus according to any one of claims 1 to 11.

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