Devices and methods for treating the lower extremity vasculature

Abstract

The present invention relates to apparatus and methods for treating the vasculature of the lower extremity, and discloses methods, apparatus and systems for diverting fluid flow from a first vessel including an occlusion to a second vessel. A prosthesis can be at least partially deployed in a fistula. Valvular insufficiency in a second vessel can be caused, for example, by cutting the valve with a reverse valvulotomy, inflating a balloon, expanding a stent, and filling the second vessel with a stent.

Description

[0001] This application is a divisional application of Chinese patent application 201580043307.2, filed on June 16, 2015, and entitled “Device and method for treating the lower limb vascular system”.

[0002] Incorporation by Reference

[0003] This application claims the benefit of priority to U.S. Patent Application No. 14 / 718,427, filed on May 21, 2015, U.S. Provisional Patent Application No. 62 / 136,755, filed on March 23, 2015, U.S. Provisional Patent Application No. 62 / 047,558, filed on September 8, 2014, and U.S. Provisional Patent Application No. 62 / 014,554, filed on June 19, 2014, each of which is incorporated herein by reference in its entirety. PCT Patent Application No. PCT / US2014 / 019607, filed on February 28, 2014, U.S. Patent Application No. 11 / 662,128, filed on January 3, 2008, U.S. Patent Application No. 12 / 297,498, filed on February 25, 2009 and published as U.S. Patent Application No. 8,439,963 on May 14, 2013, and U.S. Patent Application No. 13 / 791,185, filed on March 8, 2013, are also incorporated herein by reference in their entireties. Technical Field

[0004] The present application relates to methods and systems for use in percutaneous interventional procedures. In particular, the present application relates to methods and systems for providing or maintaining fluid flow through body passages such as heart chambers and blood vessels. Background Art

[0005] Minimally invasive percutaneous surgery or "key-hole" surgery is a surgical technique in which surgical devices are inserted into a patient's body cavity through a small hole cut in the skin. This form of surgery has become increasingly popular because it allows patients to endure less surgical discomfort while maintaining the benefits of traditional surgery. Patients treated with this technique are susceptible to lower levels of discomfort, the need for general anesthesia, trauma, and risk of infection, and their recovery time can be significantly reduced compared to traditional surgical procedures.

[0006] For example, keyhole surgery can be used for laparoscopic surgery and for the treatment of cardiovascular disease.In the treatment of cardiovascular disease, balloon angioplasty can be used as an alternative to open heart surgery for the treatment of partially occluded coronary arteries, in which a balloon catheter is inserted into an artery usually near the patient's groin and is guided to the patient's heart, and the balloon at the distal end of the catheter is expanded in the heart so that the occluded vessel widens or expands to help restore blood flow to the heart tissue. Tubular support devices (for example, stents) can be deployed at the position of obstruction to prevent future occlusion (restenosis) or collapse of blood vessels. For example, stents can be expandable metal mesh tubes carried on the balloon of a balloon catheter, or can be self-expanding. When the balloon expands, the expandable stent of the balloon expands so that the stent pushes the vessel wall. When the stent, for example, reaches its expanded position by plastic deformation or by means of a mechanical locking mechanism, the stent is arranged to keep its expanded shape, thereby forming a flexible stent or support in the blood vessel. The support structure (e.g., stent) supports and expands the vessel wall to maintain the path of blood flow through the vessel. Self-expanding stents are also available, which are maintained in a collapsed state for transportation through the artery by a suitably modified catheter, and which adopt an expanded state when deployed at the site of the blockage. For example, the catheter can include a retaining sleeve that maintains the stent in a compressed or unexpanded state. Once the sleeve is removed or withdrawn from the stent, the stent expands to support and expand the vessel wall.

[0007] Balloon angioplasty is not always an appropriate measure, for example, in acute cases and in cases of complete occlusion of a coronary artery. In these cases, the usual treatment is coronary artery bypass. Coronary artery bypass surgery is an open-chest procedure or an open-heart procedure, and typically involves grafting a piece of healthy blood vessel onto a coronary artery to bypass the blockage and restore blood flow to the coronary tissue. The healthy blood vessel is typically a vein obtained from the patient's leg or arm during the course of the bypass surgery. In order to perform the procedure, the patient's heart must be exposed by opening the chest, separating the sternum, and cutting the pericardium surrounding the heart, which results in significant surgical trauma.

[0008] Traditional coronary artery bypass surgery is not always an option. Certain patients are not suitable candidates for traditional coronary artery bypass surgery due to low expectations or high risk of recovery from the significant trauma caused by the surgery, high risk of infection, lack of healthy vessels for bypass grafts, significant comorbidities, and the expected long and complicated recovery time associated with open-heart surgery. For example, factors such as diabetes, age, obesity, and smoking can exclude a portion of candidate patients who truly need this treatment. Summary of the invention

[0009] The present application provides methods and systems for overcoming certain deficiencies and / or improving percutaneous methods and systems. For example, according to several embodiments, the methods and systems described herein can improve the targeting and positioning of therapeutic administration, which can advantageously provide treatment via percutaneous techniques to patients who are not suitable for more invasive surgery. Certain embodiments described herein can provide fluid flow in channels such as coronary and / or peripheral blood vessels by creating a bypass using minimally invasive percutaneous surgical techniques.

[0010] In some embodiments, a low-porosity prosthesis is implantable in a fistula between a first vessel and a second vessel to treat an occlusion in the first vessel by diverting blood flow from the first vessel to the second vessel. The prosthesis comprises or alternatively consists essentially of: a plurality of filaments woven together into a woven structure; 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 segment configured to anchor in the first vessel; a second longitudinal segment configured to anchor in the second vessel; and a third longitudinal segment between the first longitudinal segment and the second longitudinal segment. The first longitudinal segment is cylindrical and has a first diameter. The second longitudinal segment is frustoconical and gradually transitions to a second diameter that is greater than the first diameter. At least one of the first longitudinal segment and the second longitudinal segment has a porosity configured to direct blood flow through the lumen of the prosthesis without perfusing through the sidewalls of the prosthesis.

[0011] In some embodiments, a method of causing valvular insufficiency comprises the following steps or alternatively consists essentially of the following steps: forming a fistula between a first vessel and a second vessel. The first vessel may be an artery. The second vessel may be a vein. Forming the fistula comprises inserting a first catheter into the first vessel. The first catheter comprises an ultrasound emitting transducer and a needle configured to extend radially from the first catheter. Forming the fistula further comprises inserting a second catheter into the second vessel. The second catheter comprises an ultrasound receiving transducer. Forming the fistula further comprises emitting an ultrasound signal from the ultrasound emitting transducer, and extending a needle from the first catheter after the ultrasound signal is received by the ultrasound receiving transducer. Extending the needle comprises, leaving the first vessel, traversing the interstitial tissue between the first vessel and the second vessel, and entering the second vessel. The method further comprises deploying a prosthesis at least partially in the fistula. After deploying the implantable prosthesis, blood is diverted from the first vessel to the second vessel through the prosthesis. The method further comprises causing valvular insufficiency in the second vessel. Causing valvular insufficiency in the second vessel comprises cutting the valve with a reverse valvulome, and filling the second vessel with a stent.

[0012] The stent may comprise a covering or a graft. Filling the second vessel may comprise covering a collateral vessel of the second vessel. The stent may be separate from the prosthesis. The stent may be spaced apart from the prosthesis along the length of the second vessel. The stent may be integral with the prosthesis.

[0013] In some embodiments, a method of causing valvular insufficiency comprises the following steps or alternatively consists essentially of the following steps: forming a fistula between a first vessel and a second vessel. Forming the fistula comprises inserting a catheter into the vessel. The first catheter comprises a needle configured to extend radially from the first catheter. Forming the fistula further comprises extending the needle from the first catheter. The extending needle comprises, leaving the first vessel, traversing the interstitial tissue between the first vessel and the second vessel, and entering the second vessel. The method further comprises deploying a prosthesis at least partially in the fistula between the first vessel and the second vessel. After deploying the implantable prosthesis, blood is diverted from the first vessel to the second vessel through the prosthesis. The method further comprises causing valvular insufficiency in the second vessel. Causing valvular insufficiency in the second vessel comprises at least one of the following: cutting the valve with a reverse valvulotomy, inflating a balloon, expanding a temporary stent, and filling the second vessel with an implantable stent.

[0014] The implantable stent may include a covering or a graft. Filling the second vessel may include a collateral tube covering the second vessel. The implantable stent may be separate from the prosthesis. The implantable stent may be integral with the prosthesis. The first catheter may include an ultrasound emitting transducer. Forming the fistula may include inserting a second catheter into the second vessel, the second catheter including an ultrasound receiving transducer, emitting an ultrasound signal from the ultrasound emitting transducer, and extending a needle from the first catheter after the ultrasound signal is received by the ultrasound receiving transducer.

[0015] In some embodiments, a method of causing valvular regurgitation comprises or alternatively consists essentially of the following steps: deploying a prosthesis at least partially in a fistula between a first vessel and a second vessel. After deployment of the implantable prosthesis, blood is diverted from the first vessel to the second vessel through the prosthesis. The method further comprises causing valvular regurgitation in the second vessel.

[0016] Causing valvular regurgitation in the second vessel may include cutting the valve using a reverse valvulotomy. Causing valvular regurgitation in the second vessel may include filling the second vessel with a stent. The stent may include a covering or a graft. Filling the second vessel may include covering a collateral tube of the second vessel. The stent may be separate from the prosthesis. The stent may be spaced apart from the prosthesis along the length of the second vessel. The proximal segment of the stent may longitudinally overlap the distal segment of the prosthesis. The stent may be integral with the prosthesis. Causing valvular regurgitation in the second vessel may include cutting the valve using a reverse valvulotomy, and filling the second vessel with the stent. Causing valvular regurgitation in the second vessel may include at least one of expanding a balloon and expanding a temporary stent. Causing valvular regurgitation in the second vessel may include expanding the balloon. Causing valvular regurgitation in the second vessel may include expanding a temporary stent.

[0017] In some embodiments, an implantable prosthesis for treating an occlusion in a first vessel comprises: a plurality of filaments woven together into a woven structure; a proximal end; a distal end; a sidewall between the proximal end and the distal end; an inner cavity defined by the sidewall; and a porosity sufficient to direct fluid flow through the inner cavity without perfusing through the sidewall.

[0018] The porosity may be between about 0% and about 50%. The porosity may be between about 5% and about 50%. The prosthesis may be substantially free of graft material. The prosthesis may include a first longitudinal segment having the porosity and a second longitudinal segment having a second porosity different from the porosity. The second longitudinal segment may have parameters different from the first longitudinal segment. The parameters may include at least one of a braiding angle, a filament diameter, a filament material, a woven structure diameter, a woven structure shape, and a supplementary support structure. The prosthesis may further include a third longitudinal segment between the first longitudinal segment and the second longitudinal segment. The third longitudinal segment may have parameters different from at least one of the first longitudinal segment and the second longitudinal segment. The parameters may include at least one of a braiding angle, a filament diameter, a filament material, a woven structure diameter, a woven structure shape, and a supplementary support structure. The prosthesis may further include a supplementary support structure. The supplementary support structure may include a second plurality of filaments woven together into a second woven structure, the second plurality of filaments having parameters different from the plurality of filaments. The parameter may include at least one of a braid angle, a filament diameter, a woven structure diameter, and a filament material. The supplemental support structure may include a cut hypotube. The plurality of filaments may include filaments including a shape memory material (e.g., nitinol) and filaments including a biocompatible polymer (e.g., ) prosthesis.

[0019] In some embodiments, an implantable prosthesis for treating an occlusion in a first 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 segment configured to be anchored in the first body lumen; a second longitudinal segment configured to be anchored in the second body lumen; and a third longitudinal segment between the first longitudinal segment and the second longitudinal segment. At least one of the first longitudinal segment and the third longitudinal segment comprises a porosity sufficient to direct fluid flow substantially through the lumen without perfusing through the sidewall.

[0020] The porosity may be between about 0% and about 50%. The porosity may be between about 5% and about 50%. The prosthesis may be substantially free of graft material. The second longitudinal segment may have different parameters than the first longitudinal segment. The parameters may include at least one of a braiding angle, a filament diameter, a filament material, a diameter, a shape, and a supplemental support structure. The third longitudinal segment may include a second porosity different from the porosity. The first longitudinal segment may be an expandable balloon. The second longitudinal segment may be self-expanding. The prosthesis may include a plurality of filaments woven together into a woven structure. The plurality of filaments may include filaments including a shape memory material (e.g., nitinol) and filaments including a biocompatible polymer (e.g., ) of a prosthesis. The third longitudinal segment may have a parameter different from at least one of the first longitudinal segment and the second longitudinal segment. The parameter may include at least one of a braiding angle, a filament diameter, a filament material, a diameter, a shape, and a supplementary support structure. The prosthesis may further include a supplementary support structure. The first longitudinal segment may be generally cylindrical and may have a first diameter, the second longitudinal segment may be generally cylindrical and may have a second diameter greater than the first diameter, and the third longitudinal segment may be frustoconical and may gradually transition from the first diameter to the second diameter. The first longitudinal segment may be generally cylindrical and may have a first diameter, and the second and third longitudinal segments may be frustoconical and may gradually transition from the first diameter to a second diameter greater than the first diameter.

[0021] In some embodiments, an implantable prosthesis for treating an occlusion in a first vessel comprises: a plurality of filaments woven together into a woven structure; a proximal end; a distal end; a sidewall between the proximal and distal ends; an inner cavity defined by the sidewall; and a porosity between approximately 5% and approximately 50%.

[0022] The porosity may be configured to direct fluid flow substantially through the lumen.The prosthesis may include a first longitudinal segment having the porosity and a second longitudinal segment having a second porosity different from the porosity.

[0023] In some embodiments, a kit comprises a prosthesis and a fistula forming system. The kit may further comprise a device to disable a valve. In some embodiments, a kit comprises a prosthesis and a device to disable a valve. The kit may comprise a prosthesis delivery system including a prosthesis. In some embodiments, a method comprises deploying a prosthesis in a fistula between a first vessel and a second vessel. The device to disable a valve may comprise a reverse valvulotomy. The device to disable a valve may comprise a balloon. The device to disable a valve may comprise a venous stent. The venous stent may comprise a covering or a graft. The venous stent may be integral with the prosthesis.

[0024] In some embodiments, a method of diverting fluid flow from a first vessel to a second vessel comprises deploying a prosthesis at least partially in a fistula between the first vessel and the second vessel, wherein the first vessel comprises an occlusion. The prosthesis comprises a plurality of filaments woven together into a woven structure, the woven structure comprising a porosity of less than about 50%. After deployment of the implantable prosthesis, blood can be diverted from the first vessel to the second vessel through the prosthesis.

[0025] The first vessel may be an artery. The vascular passage may be a vein. The method may include expanding a fistula. The first vessel may be substantially parallel to the second vessel. Deploying a prosthesis may include allowing the prosthesis to self-expand. Deploying a prosthesis may include balloon-expanding the prosthesis. Deploying a prosthesis may include deploying a woven structure and deploying a supplementary support structure. Deploying the supplementary support structure may be before deploying the woven structure. Deploying the supplementary support structure may be after deploying the woven structure. The supplementary support structure may include a second plurality of filaments woven into a second woven structure. The supplementary support structure may include cutting a hypotube. The method may further include forming a fistula. Forming a fistula may include inserting a transmitting catheter into the first vessel and inserting a target catheter into the second vessel. The transmitting catheter may include an ultrasound transmitting transducer and a needle configured to extend radially from the transmitting catheter. The target catheter may include an ultrasound receiving transducer. Forming a fistula may include emitting an ultrasonic signal from an ultrasonic emitting transducer, performing at least one of the following during the emitting of the ultrasonic signal and until the ultrasonic signal is received by the ultrasonic receiving transducer: rotating the emitting catheter, and longitudinally moving the emitting catheter; and extending a needle from the emitting catheter after the ultrasonic signal is received by the ultrasonic receiving transducer, wherein the extending needle includes: leaving the second vessel, traversing the interstitial tissue between the first vessel and the second vessel, and entering the second vessel. The method may further include causing valve regurgitation in the second vessel. Causing valve regurgitation in the second vessel may include cutting the valve using a reverse valvulotomy. Causing valve regurgitation in the second vessel may include expanding a balloon. Causing valve regurgitation in the second vessel may include expanding a stent. Causing valve regurgitation in the second vessel may include filling the second vessel with a stent. The stent may include a covering or a graft. Filling the second vessel may include covering a collateral tube of the second vessel. The stent may be separate from the prosthesis. The stent may be spaced apart from the prosthesis along the length of the second vessel. The end of the stent may abut an end of the prosthesis. A portion of the stent may longitudinally overlap a portion of the prosthesis. The portion of the stent may be radially inward of the portion of the prosthesis. The method may include expanding the stent after deploying the prosthesis. The portion of the prosthesis may be radially inward of the portion of the stent. The method may include expanding the stent before deploying the prosthesis. The stent may be integral with the prosthesis.

[0026] In some embodiments, an implantable prosthesis for maintaining the patency of an anastomosis between an artery and a vein in a lower limb comprises: a first segment configured to reside in an artery of the lower limb, a second segment configured to reside in a vein of the lower limb, and a third segment longitudinally between the first segment and the second segment. The third segment is configured to maintain the patency of the anastomosis between the artery and the vein.

[0027] The first segment may be configured to attach to the wall of a lower extremity artery. The first segment may include a barb. The second segment may be configured to attach to the wall of a lower extremity vein. The second segment may include a barb. At least one of the first segment, the second segment, and the third segment may be self-expanding. At least one of the first segment, the second segment, and the third segment may be an expandable balloon. The length of the second segment may be greater than the length of the first segment. The second segment may be configured to disable the valve of the lower extremity vein. The second segment may be configured to cover the collateral tube of the lower extremity vein.

[0028] In some embodiments, a method of diverting fluid flow from a first vessel to a second vessel in a lower extremity includes forming an orifice between the first vessel and the second vessel, and dilating the orifice to form an anastomosis.

[0029] Forming an orifice may include pushing a wire from a first blood vessel into a second blood vessel. Forming an orifice may include traversing a needle from a first blood vessel into a second blood vessel. Expanding an orifice may include expanding an orifice using at least one balloon. Expanding an orifice may include utilizing multiple balloons with gradually larger diameters. A first balloon in a plurality of balloons may have a diameter of about 1.5 mm, and a last balloon in a plurality of balloons may have a diameter of about 3 mm. A plurality of balloons may include a first balloon with a diameter of about 1.5 mm, a second balloon with a diameter of about 2.0 mm, a third balloon with a diameter of about 2.5 mm, and a third balloon with a diameter of about 3.0 mm. Expanding an orifice using multiple balloons may include utilizing gradually larger balloon inflation pressures. The method may not include (e.g., without or exempt from) placing a prosthesis (e.g., without using a stent, a graft, a support frame, or other prosthesis). The position of the first vessel and the second vessel is maintained by the anatomical structure surrounding the first vessel and the second vessel. The method may further include placing a prosthesis in anastomosis. Placing the prosthesis in the anastomosis may include anchoring the prosthesis in at least one of a first vessel and a second vessel. The first vessel may include a lateral plantar artery. The second vessel may include a lateral plantar vein.

[0030] The methods summarized above and set forth in further detail below describe certain actions taken by a practitioner; however, it should be understood that they may also include instructions for those actions by another party. Thus, an action such as "causing a valve in the first vessel to regurgitate" includes "instructing the causing of a valve in the first vessel to regurgitate."

[0031] For the purpose of summarizing the present invention and the advantages that can be achieved, some goals and advantages are described herein. It is not necessary to achieve all of these goals and advantages according to any specific embodiment. In certain embodiments, the present invention can be embodied or performed in a manner that can achieve or optimize one advantage or a group of advantages without necessarily achieving other goals or advantages.

[0032] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will be apparent from the following detailed description with reference to the accompanying drawings, and the invention is not limited to any specific disclosed embodiment(s). The optional and / or preferred features described with reference to some embodiments may be combined with and incorporated into other embodiments. All references cited herein, including patents and patent applications, are incorporated herein by reference in their entirety. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] These and other features, aspects, and advantages of the present disclosure are described with reference to the accompanying drawings of certain embodiments, which are intended to illustrate certain embodiments and are not intended to limit the invention, wherein like reference numerals are used for like features, and wherein:

[0034] Figure 1 An example embodiment of a transmitting device that directs a signal from a first body cavity to a target device in a second body cavity is schematically illustrated.

[0035] Figure 2 It is along Figure 1 The cross section of the dashed line B–B is represented.

[0036] Figure 3 An example embodiment of a transmitting device is schematically illustrated.

[0037] Figure 4 An example embodiment of a target device is schematically illustrated.

[0038] Figure 5 Another example embodiment of a transmitting device is schematically illustrated.

[0039] Figure 6 Example embodiments of a centering device and / or a targeting device for transmission are schematically illustrated.

[0040] Figure 7 The prosthesis is schematically illustrated in position after a procedure such as arteriovenous arterialization.

[0041] Figure 8 is a side perspective view of an example embodiment of an apparatus for providing fluid flow.

[0042] Fig. 9 Shown is a shunt between two blood vessels Figure 8 equipment.

[0043] Fig.10 is a side perspective view of another example embodiment of an apparatus for providing fluid flow.

[0044] Fig.11 is a side perspective view of yet another example embodiment of an apparatus for providing fluid flow.

[0045] Fig.12 is a side perspective view of yet another example embodiment of an apparatus for providing fluid flow.

[0046] Fig.13 is a side perspective view of yet another example embodiment of an apparatus for providing fluid flow.

[0047] Fig.14A is a schematic side cross-sectional view of an example embodiment of an ultrasound transmitting catheter.

[0048] Fig. 14B is within circle 14B Fig.14A An enlarged schematic side cross-sectional view of a distal portion of an ultrasound emitting catheter.

[0049] Fig.15A is a schematic side view of an example embodiment of an ultrasound targeting catheter.

[0050] Fig. 15B is within circle 15B Fig.15A An enlarged schematic side cross-sectional view of an ultrasound target catheter.

[0051] Fig. 15C is within circle 15C Fig.15A An enlarged schematic side cross-sectional view of an ultrasound target catheter.

[0052] Fig.16 is an example embodiment of a diagram for detecting catheter alignment.

[0053] Fig.17 is a schematic side view of an example embodiment of a prosthesis delivery system.

[0054] Fig.18 is a schematic side view of an example embodiment of a prosthesis.

[0055] Fig.19 is a schematic side view of another example embodiment of a prosthesis.

[0056] Figures 20A-20H An example embodiment of a method of achieving retrograde perfusion is schematically illustrated.

[0057] Fig.21 is a schematic perspective view of an example embodiment of an ultrasound receive transducer.

[0058] Fig. 22 is a schematic cross-sectional view of another example embodiment of an ultrasound receive transducer.

[0059] Fig.23A is a schematic perspective view of an example embodiment of a valvulotome.

[0060] Fig. 23B is a schematic perspective view of an example embodiment of a reverse valvulotome.

[0061] Fig.24 is a schematic perspective view of an example embodiment of a LeMaitre device.

[0062] Fig.25A is a schematic side view of yet another example embodiment of a prosthesis.

[0063] Fig.25B is a schematic side view of yet another example embodiment of a prosthesis.

[0064] Fig.25C is a schematic side view of yet another example embodiment of a prosthesis.

[0065] Fig.26A and Fig.26B Another example embodiment of a method for achieving retrograde perfusion is schematically illustrated.

[0066] Fig. 27 Another example embodiment of a prosthesis and method for achieving retrograde perfusion is schematically illustrated.

[0067] Fig.28A and Fig.28B The arteries and veins of the foot are schematically illustrated separately.

[0068] Fig.29 An example embodiment of a stapling device is schematically illustrated.

[0069] Fig.30 An example embodiment of two blood vessels coupled by a stapling device is schematically illustrated.

[0070] Fig.31A An example embodiment of an arteriovenous fistula stent is schematically illustrated separate from an example embodiment of a venous stent.

[0071] Fig.31BAn example embodiment of an arteriovenous fistula stent including an integrated venous stent is schematically illustrated.

[0072] Fig.31C An example embodiment of a fistula stent comprising an integrated venous stent is schematically illustrated. DETAILED DESCRIPTION

[0073] Although certain embodiments and examples are described below, the invention extends beyond the specifically disclosed embodiments and / or applications and obvious variations and equivalents thereof. The scope of the invention disclosed herein should not be limited by any (one or more) specific embodiments described below.

[0074] Minimally invasive surgery can provide a means for treating a wider range of patients, including those currently excluded from standard surgical techniques. One such procedure is percutaneous in situ coronary venous arterialization (PICVA), which is a catheter-based coronary artery bypass procedure in which the occlusion in the diseased artery is "bypassed" by establishing a pathway between the coronary artery and the adjacent coronary vein. In this way, arterial blood is diverted to the venous system and can perfuse cardiac tissue in a retrograde manner (retrograde perfusion) and restore blood supply to ischemic tissue. Some example devices and methods for performing procedures such as PICVA are described in PCT Publication No. WO99 / 049793 and U.S. Patent Publication No. 2004 / 0133225, which are incorporated herein by reference in their entirety.

[0075] Successfully executing minimally invasive procedures that divert blood flow from coronary arteries to adjacent veins has a low success rate so far, often due to the inability to properly target veins from arteries. Due to the lack of appropriate systems and methods, such procedures (for example, attempting to target veins by a combination of X-ray fluoroscopy and an imaging ultrasound probe positioned on the distal end of a catheter, such as described in U.S. Patent Publication No. 2004 / 0133225) are often destined to fail even before starting. In fact, such an arrangement may be difficult to navigate, and the positioning of adjacent veins may require considerable skill with respect to clinicians. In general, improvements in systems and methods (such as those using catheters described herein) for targeting may be able to realize procedures such as PICVA and transvascular surgery generally. Without this improvement, such percutaneous techniques remain secondary for conventional open heart surgery and other types of bypass surgeries.

[0076] According to several embodiments, the present application describes methods and systems that can be used in minimally invasive surgical procedures that can reduce the performance of traditional surgery to treat conditions such as coronary heart disease and critical limb ischemia. For example, patients who may otherwise not be able to undergo surgery such as coronary artery bypass surgery or peripheral artery bypass surgery can be treated, and the amount of surgical trauma, infection risk, and / or recovery time can be reduced or significantly reduced compared to traditional surgery.

[0077] Figure 1 An example embodiment of a transmitting device 10 that directs a signal from a first body cavity 30 to a target device 20 in a second body cavity 35 is schematically illustrated. The transmitting device 10 includes a signal transmitter 12. The transmitting device 10 may include, for example, a catheter including an elongated flexible rod-shaped portion and a tip portion, and may provide a conduit for administering treatment within a patient's body. The transmitting device 10 may be suitable for positioning and moving through a first lumen or vessel 30 (e.g., a ventricle, a coronary artery, a coronary vein, a peripheral artery, a peripheral vein) within a patient's body. The elongated portion of the transmitting device 10 includes an outer sheath 11 that surrounds a space that defines an inner cavity 13. The space within the inner cavity 13 may be appropriately divided or subdivided as needed to define pathways for administering treatment, controlling the positioning of the transmitting device 10, and the like. For example, such subdivision may be achieved longitudinally or concentrically in an axial manner.

[0078] The transmitting device 10 includes a signal transducer 12. The signal transducer 12 is configured to provide or emit a signal 40 directed outwardly from the transmitting device 10. Figure 1 In the embodiment shown in , the signal 40 is directed radially outward from the transmitting device 10 in a direction perpendicular to the longitudinal axis of the transmitting device 10. As mentioned in more detail below, in some embodiments, the direction of the signal 40 need not be perpendicular to the longitudinal axis of the transmitting device 10 and may be directed at an angle to the longitudinal axis of the transmitting device 10. The signal transducer 12 may thus form at least a part of the signal generating means.

[0079] The signal transducer 12 is connected to a signal transmitter 50. The signal transmitter 50 may be appropriately selected from an ultrasound source or a suitable electromagnetic source, such as a laser, microwave radiation, radio waves, etc. In some embodiments, as described in further detail below, the signal transmitter 50 is configured to generate an ultrasound signal, which is forwarded to the signal transducer 12, which in turn directs the signal 40 out of the first body cavity 30 into the surrounding tissue.

[0080] The target device 20 is located in an adjacent second body cavity or vessel 32 (e.g., a ventricle, a coronary artery, a coronary vein, a peripheral artery, a peripheral vein) in the patient's body. The first body cavity 30 and the second body cavity 32 are separated by an intervening tissue 34, which is sometimes referred to as interstitial tissue or a septum. The first body cavity 30 and the second body cavity 32 are positioned adjacent to each other in a parallel manner for at least a portion of their respective lengths. For example, it is known that many veins and arteries of the body extend parallel to each other for at least a portion of their total lengths.

[0081] The target device 20 may adopt an arrangement similar to that of the launch device 10. For example, the target device 20 may include a catheter including an elongated flexible rod-shaped portion and a tip portion. For another example, fine movement and positioning of the target device 20 within the body cavity 32 may be achieved. For yet another example, the target device 20 may include an outer sheath 21 that surrounds a space and defines an inner cavity 23. The inner cavity 23 may be appropriately divided, for example, as with the launch device 10.

[0082] The target device 20 includes a receiving transducer 22 configured to receive a signal 40 from the transducer 12 of the transmitting device 10. The receiving transducer 22 constitutes at least a part of the signal detection means. In use, when the receiving transducer 22 receives the signal 40 transmitted from the signal transducer 12, the receiving transducer 22 transmits the received signal to the 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 may be a visual display, an audio display (e.g., beeps or emits some other sound upon receiving a signal), etc.

[0083] In this manner, the transmission and detection of directed signals 40 may allow for navigation and positioning of the transmitting device 10 relative to the target device 20. In use, the transmitting device 10 and the target device 20 may be manipulated by a user of the system until the output display 61 indicates that the signal 40 is being received by the target device 40.

[0084] In some embodiments, the signal 40 comprises an ultrasonic signal 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 (e.g., the width of the signal band increases as the distance from the signal transducer 12 increases). Therefore, the alignment accuracy between the transmitting device 10 and the target device 20 depends not only on the signal detection, but also on the distance between the two devices-because the signal beam width is larger at a greater distance. This level of error is called "position uncertainty". There may be a certain level of tolerance for position uncertainty; however, if the treatment is to be accurately guided, the amount of uncertainty should be reduced or minimized. For example, if the diameter d of the signal transducer 12 is 1 mm and the frequency of the ultrasonic signal is 30 MHz, the position uncertainty x (e.g., the error margin on either side of the centerline) is 1 mm at a 5 mm vertical spacing between the transmitting device 10 and the target device 20. For clinical applications, the position uncertainty (for a total signal beam width of 10 mm at the receiving point) should generally not exceed about ±5 mm. In some embodiments, the position 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 position uncertainty does not exceed about ±1 mm.

[0085] The strength of the signal 40 can be a factor in the detection, and as the distance between the transmitting device 10 and the target device 20 increases, the signal strength generally decreases. The distance is determined in part by the amount of intervening tissue 34 between the devices 10, 20. For example, if the signal 40 is an ultrasound signal, a significant decay of the signal can be expected when the transmitting device 10 and the target device 20 are separated by more than about 20 mm of solid tissue (e.g., intervening tissue 34). The density of the intervening tissue 34 can also have an effect on the decay of the signal 40 relative to the distance (e.g., denser tissue decays the signal more than less dense tissue).

[0086] The frequency of the ultrasonic signal may also affect the thickness of the signal transducer, which for a standard ultrasonic ceramic transducer (eg, piezoelectric transducer (PZT)) is 0.075 mm at 30 MHz.

[0087] Figure 2 It is along Figure 1The cross section of the dotted line B-B of FIG. The correct orientation of the transmitting device relative to the target device can be a factor in the detection because the orientation line 41 can determine where the treatment will be applied. If the pointing signal 40 is associated with the device used to deliver the treatment (e.g., parallel and longitudinally offset), the clinical need for precise placement of the treatment in the patient can be better utilized. For example, in this way, the user of the system can apply the treatment to the correct location by ensuring that the transmitting device 10 and the target device 20 are correctly positioned via the transmission and reception of the signal 40. Figure 2 The directional lines 41 in indicate not only the direction of signal travel but also the path along which therapy may be administered to the patient.

[0088] Figure 3 An exemplary embodiment of a transmitting device 10 is schematically illustrated. The transmitting device 10 comprises a signal transducer 120 oriented at an oblique angle relative to the longitudinal axis of the transmitting device 10. When the transmitting device enters the body cavity 30 ( Figure 1 and 2 ), the signal 40 is sent at an angle along the direction of travel (e.g., forward travel, lateral travel) of the transmitting device 10. In some embodiments, the beam angle is approximately perpendicular to the longitudinal axis of the transmitting device 10. In some embodiments, when 0° corresponds to the longitudinal axis of the transmitting device 10 in the direction of travel, the beam angle is between about 20° and about 60° from the vertical, between about 30° and about 50° from the vertical, or about 45° from the vertical.

[0089] The launch device 10 includes a hollow needle or cannula 17, which is an example means for administering treatment. During the travel of the launch device 10, the hollow needle 17 is located in an undeployed or retracted state within the lumen 13 of the launch device 10. The hollow needle 17 can be deployed / extended from the launch device 10 via an orifice 16 in the outer sheath 11 at a time deemed appropriate by the user (e.g., after the signal 40 is detected by the target device 20). The orifice 16 can allow fluid communication between the lumen 13 and the body cavity 30 ( Figure 1 ).like Figure 3 As shown in the exemplary embodiment of FIG. 4 , the hollow needle 17 can travel along a path parallel to the direction of the signal 40. The hollow needle 17 can be used to pierce the intervening tissue 34 ( Figure 1 In some embodiments, the hollow needle 17 makes an integral passage through the intervening tissue 34 and in doing so allows the launch device 10 to enter the second body cavity 32 ( Figure 2 If desired, the path created by the hollow needle 17 through the intervening tissue 34 can subsequently be widened to allow fluid communication between the first body cavity 30 and the second body cavity 32.

[0090] Treatment devices suitable for use in several embodiments may include, for example, devices and / or instruments selected from the following group: cannulas, lasers, radiation emitting devices, probes, drills, blades, wires, needles, suitable combinations thereof, and the like.

[0091] In some embodiments, the hollow needle 17 includes a sensor 19, which can help further determine the position information of the tip of the hollow needle 17 relative to the transmitting device 10. In some embodiments, the sensor 19 is configured to detect changes in the static pressure of the fluid. Other sensors suitable for use in the systems and methods described herein may include temperature sensors, oxygenation sensors, and / or color sensors.

[0092] Optionally, the hollow needle 17 may include an additional signal transducer 122. Figure 3 In the embodiment shown in , the signal transducer 122 is located near the tip of the hollow needle 17 on the end of the guide wire 14. If desired, the signal transducer 122 may also or alternatively be located on the hollow needle 17. In use, the signal transducer 122 is driven with a short transmit pulse that produces a directional signal and a non-directional signal pulse. The signal pulses can be detected by a receiving transducer 22 mounted on the target device 20. The distance from the guide wire 14 or hollow needle 17 to the receiving transducer 22 and therefore to the target device 20 can be determined at least in part by the time based on the delay between the transmission of the signal pulse from the signal transducer 122 and the reception of the signal pulse on the receiving transducer 22.

[0093] Figure 4 An example embodiment of a target device 20 is schematically illustrated. Figure 4 In the embodiment shown in , the target device 20 is located in the body cavity 32. As mentioned above, the target device 20 includes a receiving transducer 22 for receiving the signal 40. The receiving transducer 22 can be unidirectional (e.g., only able to receive signals from one direction) or omnidirectional (e.g., able to receive signals from any direction). Arrow A shows the reverse direction of blood flow after arteriovenous arterialization (also known as PICVA) has been achieved. The target device 20 includes an omnidirectional ultrasonic signal receiving transducer 60. An optional reflective cone 601 can direct the signal 40 to the disc-shaped receiving transducer 60. The acoustic window 602 can separate the reflective 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 polyvinyl difluoride (PVDF) around the outer sheath of the target device 20. In this way, the cylinder can function in a similar or equivalent manner to the receiving transducer 60.

[0094] exist Figure 4In the embodiment illustrated in the figure, the target device 20 includes an optional passage 25 for administering a medicament such as a therapeutic agent to a patient. In some embodiments, the passage 25 acts as a conduit to allow the application of a blocking material 251, which is used to at least partially block or occlude the body cavity 32. The blocking material 251 can be appropriately selected from a gel-based substance. The blocking material 251 can also or alternatively include an embolization member (e.g., a balloon, a self-expanding stent, etc.). The placement of the blocking material 251 can be guided by moving the target device 20. The presence of a guide member 24 in the lumen 23 of the target device 20 can allow the user to precisely manipulate the position of the target device 20 as needed.

[0095] Refer again Figure 2 , the transmitting device 10 includes a signal transducer 12 that can optionally be oriented so that the signal 40 is transmitted at an angle that is non-perpendicular to the signal transducer 12. Figure 5 Another exemplary embodiment of a transmitting device 10 is schematically illustrated. In some embodiments, for example, Figure 5 In the transmitter device 10 shown in FIG. 1 , the signal transducer is in the form of a signal transducer array 123. The signal transducer array 123 includes a plurality of signal transducer elements 124 that may be collectively oriented to at least partially define a signal beam width and angle relative to the transmitter device 10. The smaller size of the elements 124 may allow the signal transducer 123 to not occupy a significant proportion of the inner cavity 13 of the transmitter device 10.

[0096] Figure 5 The embodiment shown in can be used for ultrasound beamforming signals. Figure 5 An array of signal transducer elements 124 are shown connected to the transmitter 50 respectively via delay elements 51, which allow the signals to each element 124 to be delayed relative to each other. The delay elements can provide or ensure that the ultrasound wave front from each element 124 is aligned to produce a beam of ultrasound 40 at a desired angle. For example, in some embodiments where the signal 40 includes visible light, an array of LEDs can also or alternatively be used.

[0097] Figure 6 Schematically illustrated are example embodiments of a centering device 10 and / or a targeting device 20 for launch. To aid the alignment process between a launch device 10 in a first body cavity 30 and a targeting device 20 in a second body cavity 32, one or both of the devices 10, 20 may include means for centering the respective device within their body cavities.

[0098] In some embodiments, the centering device includes an expandable sac or balloon 111, which is located in the inner cavity 13, 23 when not deployed and can be expanded when the device 10, 20 reaches the desired position in the patient. The balloon 111 can be disposed on the outer surface of the outer sheath 11, 21. The balloon 111 is annular in shape so that it at least partially surrounds the device 10, 20 in a toroidal or doughnut-like manner. The balloon 111 can be arranged so that it expands on only one side or only two opposite sides of the device 10, 20. Figure 6 As shown in , the balloon 111 is deployed on one side of the launching device 10.

[0099] In some embodiments, the centering device includes one or more ring structures 112 in an undeployed or retracted state located in the inner cavity 13, 23 or in a recess made in the outer sheath 11, 21. When the device 10, 20 reaches the desired position in the patient, the one or more ring structures 112 can expand radially outward from the device 10, 20, thereby centering the device 10, 20 in the body cavity 30, 32. The outward expansion of the ring structure 112 can be appropriately achieved by compressing a certain length of wire, for example, so that it is bent outward from the outer sheath 11, 21 into an arc shape. A centering device using this structure may include multiple compressible lengths of wire or other suitable flexible materials arranged in parallel at radial spatial intervals around the periphery of the outer sheath 11, 21. Compression of the multiple wires can be caused by a sliding member (not shown) positioned proximally and / or distally near the ends of the multiple wires. The sliding member is capable of moving translationally along the longitudinal axis of the device 10, 20. As Figure 6 As illustrated in , the targeting device 20 includes a fully deployed centering arrangement 112 that allows the targeting device 20 to be centered within the body cavity 32 .

[0100] Other possible means of centering the device 10, 20 within the body lumen 30, 32 include, but are not limited to, an expandable Chinese lantern-shaped device, a reversibly expandable stent, a coil, a helix, a retractable stylet or legs, combinations thereof, and the like.

[0101] In some embodiments, a centering device or other device (e.g., a balloon, a metal stand-off with different lengths, etc.) can be used to orient the device 10, 20 within the body cavity 30, 32 rather than in the center of the body cavity or substantially in the center of the body cavity. For example, the device 10 can be oriented close to the wall of the body cavity 30, and the needle 17 will leave the body cavity 30 at the wall of the body cavity 30, for example, because the needle 17 passes through the intraluminal space, which can provide a shorter ultrasound signal path and / or reduce errors. For another example, the device 10 can be oriented close to the wall of the body cavity 30 opposite to the wall of the body cavity 30, where the needle 17 will leave the body cavity 30, which can, for example, provide a solid surface for the needle 17 to push against. For yet another example, the device 20 can be oriented close to the wall of the body cavity 32, where the needle 17 will enter the body cavity 32, which can, for example, provide a shorter ultrasound signal path. Other device orientations that are not centered nor close to the vessel wall are possible (eg, some fraction of the diameter away from the wall and / or center of the lumen, such as 1 / 2, 1 / 3, 1 / 4, etc.).

[0102] Example

[0103] The methods and systems described herein demonstrate specific application in cardiovascular surgery according to several embodiments. Certain aspects are further illustrated by the following non-limiting example, in which the system is used by a clinician to perform a PICVA procedure, thereby enabling retrograde perfusion of cardiac tissue after occlusion of a coronary artery.

[0104] The launch catheter 10 is inserted into the occluded coronary artery by standard keyhole surgical techniques (e.g., tracking on a guidewire, tracking through a guide catheter). The target catheter 20 is inserted into the coronary vein that runs parallel to the coronary artery by standard keyhole surgical techniques (e.g., tracking on a guidewire, tracking through a guide catheter). The coronary vein is not occluded and, therefore, provides an alternative pathway for blood flow to the myocardium, effectively bypassing the occlusion in the coronary artery.

[0105] The transmitting catheter 10 includes a PZT ultrasonic transducer 12 (e.g., available from CTS Piezoelectric Products of Albuquerque, New Mexico, USA), which is oriented so that a directional ultrasonic beam is transmitted at a 45° angle (relative to the longitudinal axis of the transmitting device) in this example, preferably in the direction of blood flow in the artery 30, but other angles including about 90° are also possible. The ultrasonic transducer 12 is activated and a 30 MHz directional ultrasonic signal 40 is transmitted from the transmitting catheter 10 in this example, but other frequencies are also possible. The target catheter 20 includes an omnidirectional ultrasonic receiving transducer 60. To assist in positioning both the transmitting catheter 10 and the target catheter 20, both catheters 10, 20 include a centering or orienting device, which in this example is in the form of an annular expandable balloon 111, but other centering or orienting devices are also possible or the lack of a centering or orienting device is also possible. When the transmitting catheter 10 is considered to be in a suitable position near the occlusion site in the coronary artery 30, the centering device 111 on the transmitting catheter 10 is deployed by the clinician. This can be determined via standard fluoroscopic imaging techniques and / or according to physical resistance. The target catheter 20 then moves in the adjacent coronary vein 32 until the guided ultrasonic signal 40 is detected by the signal receiving transducer 60. In order to enable more precise alignment to be achieved between the transmitting catheter 10 and the target catheter 20, the centering device 111 on the target catheter 20 can be deployed before or after the signal 40 is detected.

[0106] After receiving the transmitted signal 40, the clinician can determine that both the transmitting catheter 10 and the target catheter 20 are properly positioned rotationally and longitudinally within their respective blood vessels 30, 32 to allow the arterial-venous connection procedure to be initiated. The target catheter 20 can be used to occlude blood flow within the coronary vein 32 via the application of the gel occluding material 251 through the passage 25 in the target catheter 20. The occluding material 251 can be applied at a location in the coronary vein 32 downstream of venous blood flow relative to the location of the receiving signal transducer 60.

[0107] The clinician can then start the venous-arterial connection by deploying the hollow needle 17 from the transmitting catheter 10 substantially along a path, wherein the path is parallel to and close to the path taken by the ultrasound signal 40 through the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, or the hollow needle 17 can pass through a path that intersects the ultrasound signal path at a point within the coronary vein 32. The hollow needle 17 optionally includes a sensor 19 near its tip, which is configured to detect changes in hydrostatic pressure or Doppler flow, so that when the hollow needle 17 passes between the two vessels 30, 32, the user can monitor the transition from arterial pressure to venous pressure. Optionally, the hollow needle 17 includes a guide wire 14 in the hole or lumen of the hollow needle 17 during deployment. Once the hollow needle 17 and the guide wire 14 pass through the intervening tissue 34, the hollow needle 17 can be retracted into the lumen 13 of the transmitting catheter 10, leaving the guide wire 14 in place. In some embodiments, once the hollow needle 17 has passed through the intervening tissue 34 , the user may separately pass the guidewire 14 through the bore or lumen of the hollow needle 17 and then retract the needle 17 into the launching catheter 10 .

[0108] The clinician withdraws the launch catheter 10 from the patient, leaving the guidewire 14 in place. A further catheter device is then slid over the guidewire 14. Figure 7 Schematically illustrated is a prosthesis 26 (such as an expandable stent 26) in place after a procedure such as arterial-venous arterialization. Further details about possible prostheses including stents and stent grafts are provided below. Stent 26 can be deployed to widen the perforations in the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, wherein the intermittent arrow A represents the blood flow direction of the stent 26 between the first and second body cavities 30, 32 (e.g., arterial blood is thus turned to the venous system and can retrogradely perfuse myocardial tissue). Stent 26 can block the upward flow in the body cavity 32, forcing the blood flow in the body cavity 32 to be in the same direction as the blood flow in the body cavity 30. The graft material of stent 26 can form a liquid-tight cavity between the body cavity 30 and the body cavity 32. The target catheter 20 is withdrawn from the patient, leaving the blocking material 251 in place. Optionally, further blocking or suturing can be inserted into the coronary vein to inhibit or prevent the reversal of arterial blood flow, as described in further detail herein.

[0109] Although the specific examples described above are about cardiovascular surgery, the methods and systems described herein can have far-reaching applications in other forms of surgery. For example, any surgery involving the need to guide treatment from one body cavity (e.g., for the treatment of peripheral arterial disease) toward another adjacent body cavity can be considered. Therefore, applications in the fields of neurosurgery, urology, and general vascular surgery are also possible. This type of treatment is not limited to forming pathways between body cavities. For example, the methods and systems described herein can also be used in guiding technologies such as catheter ablation, non-contact mapping of the ventricles, delivery of drugs to precise areas of the body, and the like.

[0110] Some techniques for effectively bypassing occlusions in arteries through percutaneous surgery are described above. These techniques include establishing a passage or channel between a first channel and a second channel near the first channel to interconnect the first channel and the second channel through a third channel, wherein the first channel is such as an artery, vein or ventricle upstream of the occlusion, and the second channel is such as an artery, vein or ventricle. Fluids such as blood can be diverted from the first channel to the second channel via the interconnected third channel. In embodiments where the first channel includes an artery and the second channel includes a vein, arterial blood can be perfused into the tissue in a retrograde manner (retrograde perfusion).

[0111] As described above, an interconnecting channel between a first body passage and a second body passage can be established by, for example, deploying a needle outwardly from a first catheter located within the first passage so that the needle passes through interstitial tissue or a septum between the first passage and the second passage. A second catheter can be located in the second passage, thereby providing a target device that receives a signal (e.g., an ultrasound signal) transmitted from the first catheter. By monitoring the received signal, the position of the first catheter relative to the second catheter can be determined, thereby ensuring that the needle is deployed in the correct position and orientation to establish a channel for fluid flow between the first passage and the second passage.

[0112] In order to provide or maintain blood flow through the interconnected channels or passages, a structure comprising an inner cavity can be inserted into the channel to support interstitial tissue and / or to inhibit or prevent channel closure. For example, as described herein, the tube can include a stent that expands or self-expands in the passage using a balloon catheter. A catheter (e.g., a balloon catheter or a catheter that allows self-expansion) that delivers the structure can be guided to the passage by a guidewire deployed by a first catheter in the passage.

[0113] Channels such as arteries, veins, and ventricles can pulsate as the heart beats, for example due to movement of the heart wall, peripheral limbs, and / or fluctuations in pressure within the channel itself. This pulsation can cause the channels to move relative to each other, which can impose stress on the structures in the interconnected channels therebetween. This stress may be large compared to the stress experienced by the structure in a single channel. For example, due to fatigue failure of stent struts, stress can cause premature failure of the structure. The failure of the structure may result in damage to interstitial tissue and / or occlusion of the interconnected channels, which may result in significant complications or complete failure of treatment.

[0114] Figure 8 A device or implant or prosthesis 100 for providing or maintaining fluid flow through at least one channel is illustrated. The device 100 includes a first or proximal portion 102, a second or distal portion 104, and an intermediate portion 106 between the proximal portion 102 and the distal portion 104. The device includes a hole or lumen 110 for fluid to pass through the device 100. The device 100, such as at least the intermediate portion 106 of the device 100, includes a flexible polymer tube 108. The flexible polymer tube 108 can at least partially define the lumen 110.

[0115] The device 100 includes 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 in the outer wall of the tube 108 near the proximal portion 102 of the device 100. In some embodiments, at least a portion of the mesh 114 (e.g., wires or struts) is embedded in the outer wall of the tube 108 near the distal portion 104 of the device 110. The meshes 112, 114 may include a biocompatible metal (such as stainless steel) and / or a shape memory material (such as nitinol or chrome cobalt).

[0116] Wire meshes 112, 114 may stiffen ends 102, 104, respectively. In some embodiments where middle portion 106 does not include a mesh, middle portion 106 may be relatively flexible compared to ends 102, 104, and / or ends 102, 104 may have a relatively high radial stiffness.

[0117] In certain embodiments, the end 102,104 of device 100 is expandable along diameter.For example, wire mesh 112,114 can have smaller diameter compared with the passage (such as blood vessel) in which device 100 will be deployed after formation or manufacture.When device 100 is in a suitable position in passage, end 102,104 can expand or deform outwardly, so that the respective diameter of end 102,104 increases, for example, with the inner side wall of adjacent passage.For example, by the plastic deformation of the material (for example, wire, pillar) of mesh 112,114 and / or by providing the locking mechanism that is arranged to mechanically lock mesh 112,114 in the expanded position, end 102,104 is configured to maintain the diameter of expansion indefinitely (indefinitely).The middle part 106 of device 100 can be expandable along diameter, for example, via the plastic deformation of pipe 108.

[0118] Fig. 9 Show Figure 8 The device 100 is configured to provide a fluid flow path between a first channel 116 and a second channel 118. The channels 116, 118 may include coronary vessels, such as coronary arteries 116 and coronary veins 118, or vice versa. The channels 116, 118 may include peripheral vessels (e.g., vessels in the limbs), such as femoral arteries or other peripheral arteries 116 and femoral veins or other peripheral veins 118, or vice versa. The ends 102, 104 and the middle portion 106 of the device 100 have been expanded to contact and push against the inner walls of the channels 116, 118. The distal portion 104 of the device 100 is located in the second channel 118, and the proximal portion 102 of the device 100 is located in the first channel 116. The middle portion 106 extends through an opening or interconnecting channel 130 surgically formed between the channels 116, 118.

[0119] The expanded ends 102, 104 of the device 100 are resilient and impart an outward radial force to the inner walls of the passages 116, 118. Due to the radial rigidity of the ends 102, 104 of the device 100, the ends 102, 104 are held or anchored in place within the respective passages 116, 118. Sliding of the device 100 within the passages 116, 118 is thus prevented or reduced. In this manner, the ends 102, 104 of the device 100 can anchor or secure the device 100 in place, in use, while providing or maintaining fluid flow ( Figure 8 ). In this way, the device 100 can act as a shunt between the first channel 116 and the second channel 118.

[0120] The middle portion 106 of the device 100 may be flexible, for example, allowing the middle portion 106 to form an 'S' shape (eg, a shape formed by the combination of the first channel 116, the second channel 118, and the interconnecting channel 130) Fig. 9 In response to relative movement of the channels 116 , 118 , the flexible middle portion 106 can allow the ends 102 , 104 of the device 100 to move relative to each other.

[0121] In embodiments where the intermediate portion 106 does not comprise a wire mesh but rather comprises a tube 108 of a flexible polymer material, the intermediate portion 106 may be less susceptible to damage due to mesh fatigue, such as from cyclic or other stresses imparted by relative movement through the channels 116 , 118 .

[0122] The middle portion 106 of the device 100 has sufficient elasticity to maintain the expansion of the interconnecting channel 130 so that the interconnecting channel 130 remains open to provide or maintain a blood flow path from the artery 116 to the vein 118 via the lumen 110 of the tube 108 ( Figure 8 ). Blood flow from artery 116 to vein 118 via interconnecting channel 130 can thus be provided or maintained through lumen 110 of tube 108. Device 100 at least partially supports artery 116, vein 118, and interconnecting channel 130, thereby providing a path for fluid communication through device 100.

[0123] The proximal portion 102 and the distal portion 104 of the device 100 are arranged so that, when the device 100 is deployed with the distal portion 104 in the vein 118 and the proximal portion 102 in the artery 116, for example, Fig. 9 , the diameter of the expanded distal portion 104 is sufficient to maintain the distal portion 104 within the vein 118, and the diameter of the expanded proximal portion 102 is sufficient to maintain the proximal portion 102 within the artery 116. The diameter of the proximal portion 102 can therefore be different than the diameter of the distal portion 104. By selecting appropriate diameters for the end portions 102, 104 and the middle portion 106, the device 100 can be customized for certain anatomies and / or the anatomies of individual patients.

[0124] We will now describe the Figure 8 The device 100 is used to provide a shunt between an occluded artery 116 and vein 118 (e.g., a coronary artery 116 and a coronary vein 118, or a peripheral artery 116 and a peripheral vein 118) to achieve retrograde perfusion of arterial blood, such as Fig. 9 As shown in .

[0125] The catheter can be inserted into the patient's arterial system via a small orifice usually cut in the patient's groin area. The catheter is supplied to the artery 116 and guided to a position upstream of the occlusion site, for example, at a position close to and parallel to or substantially parallel to the vein 118. The hollow needle is deployed from the catheter, through the wall of the artery 116, through the interstitial tissue 132 that separates the artery 116 and the vein 118, and through the wall of the vein 118. The path of the needle establishes an interconnecting channel or opening 130, which allows blood to flow between the artery 116 and the vein 118. The deployment of the needle can be guided by a transmitter (e.g., a directional ultrasound transmitter) coupled to the catheter in the artery 116 and a receiver (e.g., an omnidirectional ultrasound receiver) coupled to the catheter in the vein 118, or vice versa, for example as described herein and in U.S. Patent Application No. 11 / 662,128. Other methods of forming the opening 130 are also possible (e.g., from vein to artery, with or without directional ultrasound guidance, with guidance of other types such as described herein, etc.).

[0126] Before the needle is withdrawn from channel 130, a guide wire (e.g., Figure 3 A guide wire 14 (described above) is inserted through the hollow needle and into the vein 118. The needle is then retracted, leaving the guide wire in place in the artery 116, the passage 130, and the vein 118. The catheter carrying the needle can then be withdrawn from the patient's body. The guide wire can be used to guide a further catheter to the interconnecting passage 130 between the artery 116 and the vein 118.

[0127] A catheter carrying the device 100 in a non-expanded state is advanced toward the interconnecting channel 130, guided by a guidewire, such as by a rapid exchange lumen or guided through the lumen 110. For example, the catheter may include a balloon catheter configured to expand at least a portion of the device 100 and / or a catheter configured to allow self-expansion of at least a portion of the device 100. The distal portion 104 of the device 100 passes through the interconnecting channel 130 and enters the vein 118, leaving the proximal portion 102 in the artery 116. The middle portion 106 of the device 100 is at least partially in the channel 130 and at least partially within the artery 116 and the vein 118. The middle portion 106 is curved to adopt a curved or "S" shaped configuration, depending on the anatomical structure of the site. Such a curvature can be adopted so that the shape of the middle portion 106 extending through the interconnecting channel 130 and optionally entering at least one of the channels 116, 118 is consistent with the shape of at least the interconnecting channel 130.

[0128] For example, the distal portion 104 of the device 100 expands after balloon inflation or by self-expansion, thereby increasing the diameter of the distal portion 104 and anchoring the distal portion 104 against the inner wall of the vein 118. The catheter can be adapted to expand the middle portion 106 of the device 100, such as by inflation of a balloon, so that the interconnecting channels 130 can be widened or enlarged to obtain blood flow (e.g., sufficient blood flow) from the artery 116 to the vein 118. For example, the proximal portion 102 of the device 100 expands after balloon inflation or by self-expansion, thereby increasing the diameter of the proximal portion 102 and anchoring the proximal portion 102 against the inner wall of the artery 116.

[0129] After the ends 102, 104 of the device 100 are expanded, for example due to self-expansion and / or balloon expansion, and with or without improved expansion after deployment, the catheter and guidewire are withdrawn from the patient's body. In this manner, the device 100 is anchored or secured in place within the vein 118, artery 116, and interconnecting channel 130, such as Fig. 9 In embodiments where device 100 includes a stent graft, the graft, which can form a fluid-tight passage between artery 116 and vein 118, can inhibit or prevent antegrade flow of blood in vein 118 because such passage is blocked, which can be in addition to or in place of an occlusive agent in vein 118.

[0130] The catheter can be adapted to selectively expand the proximal portion 102, the distal portion 104, and / or the middle portion 106 of the device 100, either individually or in combination, such as by providing two or more separately inflatable balloons or balloon portions, a single balloon configured to simultaneously expand all portions of the device 100, or a single balloon configured to expand one or more selected portions of the device 100. For example, the ends 102, 104 can be self-expanding, and the middle portion 106 can be expanded by a balloon to enlarge the passage 130. In some embodiments that include balloon expansion, all or selected portions of the device 100 can be expanded simultaneously, such as by a balloon passing through the entire length of the device 100 or by multiple balloons that are longitudinally spaced to selectively expand selected portions of the device 100, and / or can be expanded sequentially by a balloon or multiple balloons. In some embodiments that include at least partial self-expansion, all or selected portions of the device 100 can be expanded, such as by proximal retraction of a sheath on or around the device 100, which can result in the device 100 being deployed from distal to proximal as the sheath is retracted proximally. Deployment of the device 100 from proximal to distal and deployment of the device 100 first in the middle and then at both ends are also possible. In some embodiments, such as in embodiments where the device 100 is at least partially conical or tapered, a conical or tapered balloon can be used to at least partially expand the device 100. In some such embodiments, the portion of the balloon proximal to the vein 118 can have a larger diameter than the portion of the balloon proximal to the artery 116, such as so that the device 100 can adapt to a changed vein diameter due to any increase in pressure or blood flow in the vein 118.

[0131] Other steps may be included in the procedure. For example, prior to deployment of the device 100, a balloon catheter may be guided to the interconnecting channel 130 and positioned so that the expandable balloon portion of the catheter is located in the interconnecting channel 130. After the balloon is inflated, the balloon pushes against the walls of the interconnecting channel 130 to widen or expand the interconnecting channel 130 to facilitate subsequent insertion of the device 100.

[0132] Fig.10 Another device 134 is illustrated that provides fluid flow through at least one channel. Device 134 includes a mesh 136 and a polymer tube 108. Mesh 136 is shown as being outside of polymer tube 108, but as described herein, it may also or alternatively be on the inside of the polymer tube and / or within the polymer tube 108. As described with respect to device 100, device 134 includes a proximal portion 102, a distal portion 104, and a middle portion 106. Fig.10 In the illustrated embodiment, the web 136 extends along the entire length of the device 134 , including along the intermediate portion 106 .

[0133] 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 or layered filament mesh can be varied and / or the window size pattern of the cut mesh can be varied.

[0134] In some embodiments, the spacing may be relatively small in the proximal portion 102 and the distal portion 104, and the spacing may be relatively large in the middle portion 106. In other words, the density or window size of the mesh 136 may be relatively low in the middle portion 106, and the density or window size of the mesh 136 may be relatively high in the ends 102, 104. In some such embodiments, the middle portion 106 may be flexible compared to the ends 102, 104. The relatively rigid ends 102, 104 may be engaged and anchored in the channel. Although the mesh 136 in the middle portion 106 may be subjected to stresses such as cyclic stresses, in use, the relatively high flexibility of the middle portion 106 due to the low density or window size makes the effects of stresses lower because the middle portion can bend in response to stresses. The risk of fatigue failure of the device 134 and, in particular, the filaments or struts 138 of the mesh 136 may therefore be reduced compared to a device having uniform flexibility along its entire length.

[0135] In some embodiments, the spacing can be relatively large in the proximal portion 102 and the distal portion 104, and the spacing can be relatively small in the middle portion 106. In other words, the density of the mesh 136 can be relatively high in the middle portion 106 (or the window size of the mesh 136 can be relatively small), and the density of the mesh 136 can be relatively low in the ends 102, 104 (or the window size of the mesh 136 can be relatively large). In some such embodiments, the middle portion 106 can have a radial strength sufficient to inhibit or prevent the channel 130 from collapsing, yet still be flexible enough to bend in response to stress (such as cyclic stress). The ends 102, 104 can be joined and anchored in the channel.

[0136] Fig.11Another device or implant or prosthesis 140 that provides fluid flow through at least one channel is illustrated. As described with respect to device 100, device 140 includes a proximal portion 102, a distal portion 104, and a middle portion 106. Device 140 includes a polymer tube 108 and a support structure including a first mesh 142 and a second mesh 144. The first mesh 142 extends from the proximal portion 102 toward (e.g., into) the middle portion 106, and optionally into the distal portion 104. The second mesh 144 extends from the distal portion 104 toward (e.g., into) the middle portion 106, and optionally into the proximal portion 102. The meshes 142, 144 thus overlap each other at least at the middle portion 106. Both meshes 142, 144 may be on the outside of tube 108, on the inside of tube 108, or embedded within tube 108, or one mesh may be on the outside of tube 108, on the inside of tube 108, or embedded within tube 108 while the other mesh is variously on the outside of tube 108, on the inside of tube 108, or embedded within tube 108 (e.g., one mesh is inside tube 108 and one mesh is outside tube 108). Meshes 142, 144 may be formed, for example, by winding wire in a grid configuration around or inside polymer tube 108, by placing cut tubes around or inside polymer tube 108, by being embedded in polymer tube 108, combinations thereof, or the like.

[0137] In some embodiments, the density of the meshes 142, 144 is relatively high in their respective ends 102, 104 (or the window size of the meshes 142, 144 is relatively small) and decreases in density (or increases in window size) toward the middle portion 106. The total winding density (such as the winding density of both meshes 142, 144 combined) can be lower in the middle portion 106 than in the ends 102, 104, or the total window size (e.g., the window size of both meshes 142, 144 combined) can be larger in the middle portion 106 than in the ends 102, 104. In some such embodiments, the middle portion 106 is relatively flexible compared to the ends 102, 104. In some embodiments, the meshes 142, 144 do not extend into the middle portion, and the absence of the mesh can make the middle portion 106 relatively flexible compared to the ends 102, 104. In some embodiments, as the window size increases (e.g., longitudinally along the tapered portion of the device 140), because the width of the struts and / or filaments remains substantially constant or constant or does not increase in the same proportion as the window size, the density decreases, the mesh coverage decreases, and / or the porosity increases, which can provide a change in flexibility along the longitudinal length.

[0138] The first mesh 142 and the second mesh 144 may comprise different materials, which may allow the performance of each of the respective distal portion 102 and proximal portion 104 of the device 140 to be optimized for a specific application of the device 140. For example, the second mesh 144 at the distal portion 104 of the device 140 may comprise a relatively flexible metal alloy to facilitate insertion through an interconnecting passage between two blood vessels, while the first mesh 142 at the proximal portion 102 of the device 140 may comprise a relatively inelastic metal alloy to provide a high degree of elasticity at the proximal portion 104 to securely anchor the device 140 in place. The first mesh 142 and the second mesh 144 may comprise the same material composition (e.g., both comprise Nitinol) but comprise different wire diameters (gauges) or strut thicknesses.

[0139] Fig.12 Another device or implant or prosthesis 150 that provides fluid flow through at least one channel is illustrated. Device 150 includes a support structure (e.g., a stent) 152 and a graft 154. As described with respect to device 100, device 150 includes a proximal portion 102, a distal portion 104, and a middle portion 106. Proximal portion 102 includes a cylindrical or generally cylindrical portion, and distal portion 104 includes a cylindrical / cylindrical or generally cylindrical / cylindrical portion. The diameter of proximal portion 102 is less than the diameter of distal portion 104. In some embodiments, the diameter of proximal portion 102 is greater than the diameter of distal portion 104. Middle portion 106 has a conical or frustoconical / frustoconical shape between proximal portion 102 and distal portion 104. Stent 152 can include filaments (e.g., woven, layered), cut tubes or plates, and / or combinations thereof.

[0140] The parameters of the stent 152 can be uniform or substantially uniform across a portion and / or across multiple portions, or can vary within a portion and / or across multiple portions. For example, the stent 152 at the proximal portion 102 can include a cut tube or plate, the stent 152 at the distal portion 102 can include a cut tube or plate, and the stent 152 at the middle portion 106 can include filaments (e.g., woven or layered). Certain such embodiments can provide good anchoring through good flexibility (e.g., adaptability to third channel size and dynamic stress) of the proximal portion 102 and the distal portion 104 and the middle portion 106.

[0141] The stent 152 can include different materials in different portions. For example, the stent 152 at the proximal portion 102 can include chromium cobalt and / or tantalum, the stent 152 at the distal portion 104 can include nitinol, and the stent 152 at the middle portion 106 can include nitinol. Certain such embodiments can provide good anchoring and / or wall attachment (apposition) by the device 150 in each deployment area (e.g., the proximal portion 102 engages the side wall of the artery, the distal portion 104 engages the side wall of the vein, and the middle portion 106 engages the side wall of the passage between the artery and the vein). In some embodiments where the distal portion 104 is self-expanding, due to a changing vessel diameter (e.g., if the vein diameter increases due to an increase in blood pressure or blood flow), the distal portion 104 can adapt, for example, by further self-expanding.

[0142] Combinations of support structure materials and types are also possible. For example, the stent 152 at the proximal portion may include a cut tube or plate containing chromium cobalt and / or tantalum, the stent 152 at the distal portion 104 may include a cut tube or plate containing nitinol, and the stent 152 at the intermediate portion 106 may include a filament containing nitinol.

[0143] In embodiments where the stent 152 includes at least a portion comprising a cut tube or plate, the cutting pattern may be the same. For example, the cutting pattern may be the same in the proximal portion 102 and the distal portion 104, but in proportion to the change in diameter. In some embodiments, the window size or strut density is uniform or substantially uniform within portions 102, 104, 106, within two or more of portions 102, 104, 106, and / or from one end of the stent 152 to the other end of the stent 152. In embodiments where the stent 152 includes at least a portion comprising a filament, the winding may be the same. For example, the winding may be the same in the proximal portion 102 and the distal portion 104, but may change due to a change in diameter. In some embodiments, the winding density or porosity is uniform or substantially uniform within portions 102, 104, 106, within two or more of portions 102, 104, 106, and / or from one end of the stent 152 to the other end of the stent 152. In embodiments where stent 152 includes at least a portion comprising cut tubes or sheets and at least a portion comprising filaments, the cutting pattern and winding can be configured to result in a uniform or substantially uniform density. Non-uniformity is also possible, such as described herein.

[0144] As described with respect to tube 108, graft 154 may include material and be attached to stent 152. Graft 154 generally forms a fluid-tight passageway for at least a portion of device 150. Although illustrated only around mid-section 106, graft 154 may extend the entire length of device 150, or may partially overlap into at least one of cylindrical ends 102, 104.

[0145] Fig.13 Another device 160 for providing fluid flow through at least one channel is illustrated. Device 160 includes a support structure (e.g., a stent) and a graft 164. As described with respect to device 100, device 160 includes a proximal portion 102, a distal portion 104, and an intermediate portion 106. Proximal portion 102 includes a tapered or frustoconical portion, and distal portion 104 includes a tapered or frustoconical portion. The diameter of the proximal end of proximal portion 102 is smaller than the diameter of the distal end of distal portion 104. In some embodiments, the diameter of the proximal end of proximal portion 102 is larger than the diameter of the distal end of distal portion 104. Intermediate portion 106 has a tapered or frustoconical shape between proximal portion 102 and distal portion 104. In some embodiments, the angles of inclination of portions 102, 104, 106 are the same or substantially the same (e.g., as shown in FIG. 1 ). Fig.13 ). In some embodiments, the angle of inclination of at least one portion is sharper or narrower than at least one other portion. The frustoconical proximal and distal portions 102, 104 can allow for better anchoring in a body passage, for example because arteries tend to taper with distance from the heart and veins tend to taper with distance toward the heart, and the ends 102, 104 can be configured to taper at least in part to correspond to such anatomical tapers.

[0146] Fig.12 An apparatus 150 is illustrated that includes a first cylindrical or straight portion, a conical or tapered portion, and a second cylindrical or straight portion. Fig.13Device 160 is illustrated, which includes one or more conical or tapered portions (e.g., the entire device 160 is conical or tapered or includes multiple conical or tapered portions). In some embodiments, combinations of devices 150, 160 are possible. For example, for the remainder of the device, the device may include a cylindrical or straight portion and a conical or tapered portion. In some such embodiments, the length of the device may be between about 1 cm and about 10 cm (e.g., about 5 cm), which includes a cylindrical or straight portion and a conical or tapered portion, the cylindrical or straight portion having a diameter between about 1 mm and about 5 mm (e.g., about 3 mm) and a length between about 0.5 cm and about 4 cm (e.g., about 2 cm), the conical or tapered portion increasing in diameter from the diameter of the cylindrical or straight portion to a diameter between about 3 mm and about 10 mm (e.g., about 5 mm) and a length between about 1 cm and about 6 cm (e.g., about 3 cm). Such a device may lack another cylindrical or conical part thereafter.

[0147] As described above with respect to support structure 152, support structure 162 may include filaments (eg, woven, layered), cut tubes or sheets, the same material, different materials, and combinations thereof.

[0148] As described with respect to tube 108, graft 164 may include material and be attached to stent 162. Graft 164 generally forms a fluid-tight passage for at least a portion of device 160. Although illustrated as surrounding only mid-portion 106, graft 164 may extend the entire length of device 160, or may partially overlap at least one of frustoconical end portions 102, 104.

[0149] In some embodiments, a combination of the device 150 and the device 160 is possible. For example, the proximal portion 102 may be cylindrical or substantially cylindrical (e.g., as in the device 150), the distal portion 104 may be conical or frustoconical (e.g., as in the device 160), and the proximal portion 102 may have a larger diameter than the distal end of the distal portion 104. For another example, the proximal portion 102 may be conical or frustoconical (e.g., as in the device 160), the distal portion 104 may be cylindrical or substantially cylindrical (e.g., as in the device 150), and the proximal end of the proximal portion 102 may have a larger diameter than the distal portion 104. In each example, the intermediate portion 106 may have a conical or frustoconical shape between the proximal portion 102 and the distal portion 104.

[0150] Example deployment devices of the implantable devices described herein are described in U.S. Patent Application No. 12 / 545,982 filed on August 24, 2009 and U.S. Patent Application No. 13 / 486,249 filed on June 1, 2012, the entire contents of each of which are incorporated herein by reference. The device typically includes a handle with a user-actuated trigger at the proximal end and a combination of tubular members configured to push and / or pull to release the device after the trigger is actuated at the distal end. Other delivery devices are also possible. The delivery device may include a slidable portion on a guide wire (e.g., a guide wire that has been navigated between an artery and a vein through a needle that traverses tissue) and / or may be trackable through the lumen of a catheter.

[0151] Although certain embodiments and examples are shown or described herein in detail, various combinations, sub-combinations, modifications, variations, substitutions and omissions of the specific features and aspects of those embodiments are possible, some of which will now be described by way of example only.

[0152] Devices, such as stents of the device, meshes of the device, support structures of the device, etc., can be self-expanding. For example, the mesh can include a shape memory material, such as nitinol, which can return to a preset shape after undergoing deformation. In some embodiments, the stent can be manufactured to a desired shape in an expanded configuration and be compressible to fit within a sleeve for transport to a vascular site on a catheter. In order to deploy and expand the stent, the sleeve is withdrawn from the stent to allow the shape memory material to return to a preset shape, which can anchor the stent in the channel and, if the stent has sufficient radial strength, this can expand the channel. The use of a balloon catheter does not require expansion of a fully self-expanding stent, but can be used, for example, to improve or optimize deployment.

[0153] The device may include one or more self-expanding portions and one or more portions that are expandable by deformation, such as using a balloon catheter. Fig.11 In the embodiment shown in FIG. 1 , the first mesh 142 may include stainless steel that is expandable via a balloon catheter, and the second mesh 144 may include nitinol that self-expands after deployment.

[0154] With respect to any of the embodiments described herein, the polymer tube 108 containing the graft 154, 164 may include any suitable compliant or flexible polymer, such as PTFE, silicone, polyethylene terephthalate (PET), a polyurethane such as polycarbonate aromatic biodurable thermoplastic polyurethane elastomer (e.g., ChronoFlex 80A and 55D medical grade, available from AdvanSource Biomaterials of Wilmington, Massachusetts), combinations thereof, and the like. The polymer tube 108 may include a biodegradable, bioabsorbable or biocompatible polymer (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycolic acid-lactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.). The polymer may be in the form of a tube before interacting with a support structure (e.g., a stent), or may be formed on, in and / or around a support structure (e.g., a stent). For example, the polymer may include spun fibers, dip coatings, combinations thereof, and the like. In some embodiments, for example, when the device is to be deployed in a single blood vessel, the device may omit the tube. In some such embodiments, the middle portion of the stent may include a mesh having a low winding density or a large window size, while the ends of the stent include a mesh having a higher winding density or a smaller window size, the mesh being generally tubular to define a path for fluid flow through the center of the mesh. In some embodiments, the polymeric tube 108 includes an edge (e.g., including the same or different material) that can help form a fluid-tight seal between the polymeric tube 108 and the body passage. The seal can be angled, for example to account for the angled placement of the polymeric tube 108 between the body passage. In some embodiments, the polymeric tube 108 can extend longitudinally in at least one direction beyond the support structure, and the portion that extends beyond is not supported by the support structure.

[0155] The mesh may include any suitable material, such as nickel, titanium, chromium, cobalt, tantalum, platinum, tungsten, iron, manganese, molybdenum, combinations thereof (e.g., nitinol, chrome cobalt, stainless steel), and the like. The mesh may include a biodegradable, bioabsorbable, or biocompatible polymer (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycolic acid-lactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.) and / or glass, and may lack metal. For example, as described above with respect to Fig.11As described, different materials can be used for portions of the mesh or within the same mesh. For example, the mesh 114 at the distal portion 104 of the device 100 and the mesh 112 at the proximal portion 102 can include different materials. For another example, the mesh 112 and / or the mesh 114 can include a metal alloy (e.g., including cobalt, chromium, nickel, titanium, combinations thereof, and the like) in combination with different types of metal alloys (e.g., a shape memory alloy in combination with a non-shape memory alloy, a first shape memory alloy in combination with a second shape memory alloy different from the first shape memory alloy, a clad material (e.g., including a core containing 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 mesh 112, 114 includes nitinol and stainless steel. Nitinol may allow for some self-expansion (eg, partial and / or complete self-expansion), and the mesh may then be further expanded, for example, using a balloon.

[0156] Although in Figure 8 , 10 1 and 11 are generally illustrated as woven filament meshes, but any other structure that can provide the desired elasticity can be used. For example, the filament layers wound in opposite directions can be fused at the ends of the filaments to provide an expandable structure. For another example, a metal sheet can be cut (e.g., laser cutting, chemical etching, plasma cutting, etc.) to form perforations, and then heat-set in a tubular shape, or a metal tube (e.g., a hypotube) can be cut (e.g., laser cutting, chemical etching, plasma cutting, etc.) to form perforations. A cut tube (including a cut sheet rolled into a tube) can be heat-set to impart an expansion configuration.

[0157] Can be woven or braided, or layered or otherwise arranged filament or wire or band are normally elongated and have cross sections such as circle, oval, square, rectangle.Example nonwoven filament can comprise the first filament layer that is wound with the first direction and the second filament layer that is wound with the second direction, and at least some filament ends are coupled together (for example, by being coupled to expandable ring).Example braiding pattern comprises one on one below one / one-on-one-under-one, one on two below two / one-on-two-under-two, two on two below two / two-on-two-under-two, and / or its combination, but other braiding patterns are also possible.At the filament intersection, filament can be wrapped in spiral shape, cross with sliding relation, and / or its combination. The filaments can be loose (e.g., held together by weaving) and / or include welding points, coupling elements such as sleeves, and / or combinations thereof. The ends of the filaments can be bent backward, curled (e.g., curled ends of radiopaque materials with which radiopaque markers can also be used, such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc.), twisted, ball welded, coupled to rings, combinations thereof, and the like. The weaving end can include filament ends and / or backward-bending filaments, and can include open cells, fixed or unfixed filaments, welding points, adhesives, or other means of fusion, radiopaque markers, combinations thereof, and the like. The parameters of the filaments can be uniform or substantially uniform throughout a portion and / or throughout multiple portions, or can vary within a portion and / or throughout multiple portions. For example, the proximal portion 102 can include a first parameter and the distal portion 104 can include a second parameter that is different from the first braiding pattern. For another example, the proximal portion 102 and the distal portion 104 can each include a first parameter and the middle portion 106 can include a second parameter that is different from the parameter. For another example, at least one of the proximal portion 102, the distal portion 104 and the middle portion 106 can include both a first parameter and a second parameter that is different from the first parameter. The filament parameters can include, for example, filament type, filament thickness, filament material, filament quantity, weaving pattern, layering, winding direction, pitch, angle, cross type, filament coupling or its lack, filament end treatment, weaving end treatment, layered end treatment, the number of layers, the presence or absence of welding points, non-transmissive linearity, braiding pattern, density, porosity, filament angle, braiding diameter, winding diameter and shape settings.

[0158] The tube or plate can be cut to form a pillar or perforated pattern, and the pillar is the part of the tube or plate remaining after cutting, and the perforation or perforation or window is the part cut off. The tube (for example, a hypotube) can be cut directly, or the plate can be cut and then rolled into a tube. The tube or plate can be shaped before or after cutting. The tube or plate can be welded or otherwise coupled to itself, to another tube or plate, to a filament, to a transplant material, etc. The cutting can be by laser, chemical etchant, plasma, its combination and the like. Example cutting patterns include helical spiral, woven type, coil, single ring, continuous ring, perforation, obturator, its combination, etc. In the embodiment comprising a continuous ring, a flex connector, a non-flex connector and / or its combination coupling ring can be used. In embodiments comprising continuous rings, the ring connectors (e.g., flexed, non-flexed, and / or combinations thereof) may traverse the ring peaks, the ring valleys, the middle portions of the pillars, and / or combinations thereof (e.g., peak-peak, valley-valley, middle-middle, peak-valley, peak-middle, valley-middle, valley-peak, middle-peak, middle-valley). The tube or plate or portion thereof may be ground or polished before or after cutting. For example, internal ridges may be formed to aid fluid flow. The parameters of the cut tube or plate may be uniform or substantially uniform throughout a portion and / or throughout multiple portions, or may vary within a portion and / or throughout multiple portions. For example, the proximal portion 102 may include a first parameter, and the distal portion 104 may include a second parameter different from the first parameter. For another example, the proximal portion 102 and the distal portion 104 may each include a first parameter, and the middle portion 106 may include a second parameter different from the parameter. For another example, at least one of the proximal portion 102, the distal portion 104, and the middle portion 106 may include both a first parameter and a second parameter different from the first parameter. Cutting tube or plate parameters may include, for example, radial strut thickness, circumferential strut width, strut shape, opening shape, cut pattern, cut type, material, density, porosity, tube diameter, and shape settings.

[0159] In some embodiments, the perforations may provide a mesh having a relatively flexible middle portion and relatively rigid ends.The support structure may instead be an open cell foam disposed within the tube.

[0160] The stent, filaments of a stent graft or a portion thereof, and / or the struts of a cut stent, stent graft or a portion thereof may be surface modified, for example, to carry a drug such as a thrombosis modifier, a fluid flow modifier, an antibiotic, etc. The stent, filaments of a stent graft or a portion thereof, and / or the struts of a cut stent, stent graft or a portion thereof may be at least partially covered with a coating including a drug such as a thrombosis modifier, a fluid flow modifier, an antibiotic, etc., for example, embedded in a polymer layer or a series of polymer layers, which may be the same or different than the polymer tube 108.

[0161] The thickness (e.g., diameter) of the filaments of a stent, stent graft, or a portion thereof and / or the struts of a cut stent, stent graft, or a portion thereof can be between about 0.0005 inches and about 0.02 inches, between about 0.0005 inches and about 0.015 inches, between about 0.0005 inches and about 0.01 inches, between about 0.0005 inches and about 0.008 inches, between about 0.0005 inches and about 0.007 inches, between about 0.0005 inches and about 0.006 inches, between about 0.0005 inches and about 0.005 inches, between about 0.0005 inches and about 0.004 inches, between about 0.0005 inches and about 0.006 ... inch and about 0.003 inch, between about 0.0005 inch and about 0.002 inch, between about 0.0005 inch and about 0.001 inch, between about 0.001 inch and about 0.02 inch, between about 0.001 inch and about 0.015 inch, between about 0.001 inch and about 0.01 inch, between about 0.001 inch and about 0.008 inch, between about 0.001 inch and about 0.007 inch, between about 0.001 inch and about 0.006 inch, between about 0.001 inch and about 0.005 inch, between about 0.001 inch and about 0.004 inch, between about 0.001 inch and about 0.006 inch, between about 0.001 inch and about 0.005 inch, between about 0.001 inch and about 0.004 inch, between about 0.001 inch and about 0.006 inch, between about 0.001 inch and about 0.006 inch, between about 0.001 inch and about 0.005 inch, between about 0.001 inch and about 0.006 ... 0.001 inch and about 0.003 inch, between about 0.001 inch and about 0.002 inch, between about 0.002 inch and about 0.02 inch, between about 0.002 inch and about 0.015 inch, between about 0.002 inch and about 0.01 inch, between about 0.002 inch and about 0.008 inch, between about 0.002 inch and about 0.007 inch, between about 0.002 inch and about 0.006 inch, between about 0.002 inch and about 0.005 inch, between about 0.002 inch and about 0.004 inch, between about 0.002 inch and about 0.003 ...3 inch and about 0.004 inch 0.003 inches and about 0.02 inches, between about 0.003 inches and about 0.015 inches, between about 0.003 inches and about 0.01 inches, between about 0.003 inches and about 0.008 inches, between about 0.003 inches and about 0.007 inches, between about 0.003 inches and about 0.006 inches, between about 0.003 inches and about 0.005 inches, between about 0.003 inches and about 0.004 inches, between about 0.004 inches and about 0.02 inches, between about 0.004 inches and about 0.015 inches, between about 0.004 ...1 inches, between about 0.003 inches and about 0.008 inches, between about 0.003 inches and about 0.007 inches, between about 0.003 inches and about 0.006 inches, between about 0.003 inches and about 0.005 inches, between about 0.003 inches and about 0.004 inches, between about 0.004 inches and about 0.02 inches, between about 0.004 inches and about 0.015 inches, between about 0.0040.004 inches and about 0.008 inches, between about 0.004 inches and about 0.007 inches, between about 0.004 inches and about 0.006 inches, between about 0.004 inches and about 0.005 inches, between about 0.005 inches and about 0.02 inches, between about 0.005 inches and about 0.015 inches, between about 0.005 inches and about 0.01 inches, between about 0.005 inches and about 0.008 inches, between about 0.005 inches and about 0.007 inches, between about 0.005 inches and about 0.006 inches, between about 0.006 inches and about 0.02 inches, between about 0.006 inches and about 0.015 inches, between about 0.006 inches and about 0.01 inches Between about 0.01 inches, between about 0.006 inches and about 0.008 inches, between about 0.006 inches and about 0.007 inches, between about 0.007 inches and about 0.02 inches, between about 0.007 inches and about 0.015 inches, between about 0.007 inches and about 0.01 inches, between about 0.007 inches and about 0.008 inches, between about 0.008 inches and about 0.02 inches, between about 0.008 inches and about 0.015 inches, between about 0.008 inches and about 0.01 inches, between about 0.01 inches and about 0.02 inches, between about 0.01 inches and about 0.015 inches, or between about 0.015 inches and about 0.02 inches. Other thicknesses are also possible, including thicknesses greater than or less than the thicknesses identified. Filaments and / or struts comprising certain materials (e.g., biodegradable materials, materials with lower restoring forces, etc.) may be thicker than the thickness identified.

[0162] For example, the thickness of the filaments and / or struts can be based on at least one of the following: device or device portion size (e.g., diameter and / or length), porosity, radial strength, material, number of filaments and / or struts, cut pattern, weave pattern, layering pattern, and the like. For example, larger filament and / or strut thicknesses (e.g., greater than about 0.006 inches) can be used for large devices or device portions used to treat large vessels such as coronary vessels, medium filament and / or strut thicknesses (e.g., between about 0.003 inches and about 0.006 inches) can be used for medium devices or device portions used to treat medium vessels such as peripheral vessels, and small filament and / or strut thicknesses (e.g., less than about 0.003 inches) can be used for small devices or device portions used to treat small vessels such as veins and neurovascular vessels.

[0163] The inner or outer diameter of the stent, stent graft, or the first end, the second end, the middle portion, or a sub-portion thereof, e.g., taking into account filament or strut thickness, can be between about 1 mm and about 12 mm, between about 1 mm and about 10 mm, between about 1 mm and about 8 mm, between about 1 mm and about 6 mm, between about 1 mm and about 4 mm, between about 1 mm and about 2 mm, between about 2 mm and about 12 mm, between about 2 mm and about 10 mm, between about 2 mm and about 8 mm , between about 2 mm and about 6 mm, between about 2 mm and about 4 mm, between about 4 mm and about 12 mm, between about 4 mm and about 10 mm, between about 4 mm and about 8 mm, between about 4 mm and about 6 mm, between about 6 mm and about 12 mm, between about 6 mm and about 10 mm, between about 6 mm and about 8 mm, between about 8 mm and about 12 mm, between about 8 mm and about 10 mm, or between about 10 mm and about 12 mm. Certain such diameters may be suitable for treating, for example, coronary vessels. For example, consider filament or strut thickness, the inner diameter or outer diameter of stent, stent graft or its part can be between about 1mm and about 10mm, between about 1mm and about 8mm, between about 1mm and about 6mm, between about 1mm and about 4mm, between about 1mm and about 2mm, between about 2mm and about 10mm, between about 2mm and about 8mm, between about 2mm and about 6mm, between about 2mm and about 4mm, between about 4mm and about 10mm, between about 4mm and about 8mm, between about 4mm and about 6mm, between about 6mm and about 10mm, between about 6mm and about 8mm, or between about 8mm and about 10mm.Some such diameter can be suitable for treatment, for example, vein. For example, consider filament or strut thickness, the inner diameter or outer diameter of stent, stent graft or its part can be between about 6mm and about 25mm, between about 6mm and about 20mm, between about 6mm and about 15mm, between about 6mm and about 12mm, between about 6mm and about 9mm, between about 9mm and about 25mm, between about 9mm and about 20mm, between about 9mm and about 15mm, between about 9mm and about 12mm, between about 12mm and about 25mm, between about 12mm and about 20mm, between about 12mm and about 15mm, between about 15mm and about 25mm, between about 15mm and about 20mm, or between about 20mm and about 25mm.Some such diameter can be suitable for treatment, for example, peripheral vessels.For example, considering the thickness of filaments or struts, the inner diameter or outer diameter of a stent, stent graft, or a portion thereof can be between about 20mm and about 50mm, between about 20mm and about 40mm, between about 20mm and about 35mm, between about 20mm and about 30mm, between about 30mm and about 50mm, between about 30mm and about 40mm, between about 30mm and about 35mm, between about 35mm and about 50mm, between about 35mm and about 40mm, between about 40mm and about 50mm. Some such diameters may be suitable for treatment, for example, of the aorta. Other diameters are also possible, including diameters greater than or less than the diameter confirmed. The diameter of a device may refer to the diameter of a first end, a second end, or a middle portion, each of which may be in an expanded or unexpanded form. When all parts of a device are in an expanded or unexpanded form, the diameter of a device may refer to the average diameter of the device.

[0164] The length of the stent, stent graft, or the first end, the second end, the middle portion, or a sub-portion thereof can be between about 5 mm and about 150 mm, between about 5 mm and about 110 mm, between about 5 mm and about 70 mm, between about 5 mm and about 50 mm, between about 5 mm and about 25 mm, between about 5 mm and about 20 mm, between about 5 mm and about 10 mm, between about 10 mm and about 150 mm, between about 10 mm and about 110 mm, between about 10 mm and about 70 mm, between about 10 mm and about 50 mm, between about 10 mm and about 25 mm, between about 5 mm and about 20 mm, between about 5 mm and about 10 mm, between about 10 mm and about 20 mm, between about 20 mm and about 25 mm. 100mm, between about 25mm and about 70mm, between about 25mm and about 50mm, between about 20mm and about 250mm, between about 25mm and about 150mm, between about 25mm and about 110mm, between about 25mm and about 70mm, between about 25mm and about 50mm, between about 50mm and about 150mm, between about 50mm and about 110mm, between about 50mm and about 70mm, between about 70mm and about 150mm, between about 70mm and about 110mm, or between about 110mm and about 150mm. Other lengths are also possible, including lengths greater or less than the lengths identified.

[0165] The porosity of the stent, stent graft, or first end, second end, middle portion, or sub-portion thereof can be between about 5% and about 95%, between about 5% and about 50%, between about 5% and about 25%, between about 5% and about 10%, between about 10% and about 50%, between about 10% and about 25%, between about 25% and about 50%, between about 50% and about 95%, between about 50% and about 75%, between about 50% and about 60%, between about 60% and about 95%, between about 75% and about 90%, between about 60% and about 75%, and combinations thereof. The density of the stent can be the inverse of the porosity of the stent. The porosity of the stent portion covered by the graft can be about 0%. For certain portions of the stent, the porosity can vary with purpose. For example, the middle section may have low porosity to increase fluid flow through the device, while the ends may have lower porosity to increase flexibility and wall adhesion.

[0166] Fig.25A is a schematic side view of yet another example embodiment of a prosthesis 500. The prosthesis or stent or device 500 includes and / or consists essentially of a plurality of filaments 502 woven together into a woven structure. The stent 500 may be free of graft material, as described in further detail below.

[0167] The filaments 502, which may also be described as wires, strips, strands, etc., may be woven, braided, layered, or otherwise arranged in a cross-wise manner. The filaments 502 are typically elongated and have a cross-section of a circle, an ellipse, a square, a rectangle, etc. Example nonwoven filaments may include a first filament layer wound in a first direction and a second filament layer wound in a second direction, with at least some of the filament ends coupled together (e.g., by coupling to an expandable loop). Example woven patterns include one above one below one / one-up-one-below-one (e.g., in Fig.25A), one on two under two / one-over-two-under-two, two on two under two / two-over-two-under-two, and / or its combination, but other weaving patterns are also possible. At the intersection of filament 502, filament 502 can be wrapped in spiral shape, cross with sliding relationship, and / or its combination. Filament 502 can be loose (for example, kept together by weaving) and / or include welding points, coupling elements such as sleeves, and / or its combination. The end of filament 502 can be bent backward, curled (for example, curled with the end of the radiopaque material that can also serve as a radiopaque marker, the radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc.), twisted, ball welded (ball weld), coupled to a ring, its combination and the like. The braided ends may include filament 502 ends and / or bent-back filaments 502, and may include open cells, fixed or non-fixed filaments 502, welds, adhesives, or other means of fusion, radiopaque markers, combinations thereof, and the like.

[0168] Stent 500 includes pores 504 or open, uncovered areas between filaments 502. The porosity of stent 500 can be calculated as the outer surface area of ​​pores 504 divided by the total outer surface area of ​​stent 500. Porosity can be affected by parameters such as, for example, the number of filaments 502, the braid angle 506, the size (e.g., diameter) of filaments 502, and combinations thereof.

[0169] The porosity of the stent 500 can be less than 50% (e.g., slightly more covered than open), between about 0% (e.g., almost no open area) and about 50%, between about 0% and about 45%, between about 0% and about 40%, between about 0% and about 35%, between about 0% and about 30%, between about 0% and about 25%, between about 0% and about 20%, between about 0% and about 15%, between about 0% and about 10%, between about 0% and about 5%, between about 5% and about 50%, between about 5% and about 45%, between about 0 ... Between about 5% and about 40%, between about 5% and about 35%, between about 5% and about 30%, between about 5% and about 25%, between about 5% and about 20%, between about 5% and about 15%, between about 5% and about 10%, between about 10% and about 50%, between about 10% and about 45%, between about 10% and about 40%, between about 10% and about 35%, between about 10% and about 30%, between about 10% and about 25%, between about 10% and about 20%, between about 10% and about 15% between about 15% and about 50%, between about 15% and about 45%, between about 15% and about 40%, between about 15% and about 35%, between about 15% and about 35%, between about 15% and about 25%, between about 15% and about 20%, between about 20% and about 50%, between about 20% and about 45%, between about 20% and about 40%, between about 20% and about 35%, between about 20% and about 35%, between about 20% and about 25%, between about 25% and about 50%, between about 20% and about 45%, between about 20% and about 40%, between about 20% and about 35%, between about 20% and about 35%, between about 20% and about 25%, between about 25% and about 50%, between about Between approximately 25% and approximately 45%, between approximately 25% and approximately 40%, between approximately 25% and approximately 35%, between approximately 25% and approximately 35%, between approximately 30% and approximately 50%, between approximately 30% and approximately 45%, between approximately 30% and approximately 40%, between approximately 30% and approximately 35%, between approximately 35% and approximately 50%, between approximately 35% and approximately 45%, between approximately 35% and approximately 40%, between approximately 40% and approximately 50%, between approximately 40% and approximately 45%, between approximately 45% and approximately 50%, and combinations thereof.

[0170] In some embodiments where the porosity is less than about 50%, blood cannot perfuse through the sidewalls of stent 500 under normal vascular pressures (e.g., the pressure drop across the vessel, the pressure drop from the afferent vessel to the efferent vessel). In certain such embodiments, blood flowing into the proximal end of stent 500 can be directed through the lumen of stent 500 to the distal end of stent 500 without (e.g., substantially without, none, substantially none) graft material and still without blood loss or substantial blood loss through the sidewalls of 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 efferent vessels.

[0171] The density of scaffold 500 can be the inverse of the porosity (eg, the external surface area of ​​filaments 502 divided by the total external surface area of ​​scaffold 500). The density of scaffold 500 can be 100% minus the porosity value provided above.

[0172] The filaments 502 are arranged relative to an axis perpendicular to the longitudinal axis of the stent 500 (e.g., as in Fig.25A 506). The braiding angle 506 can range from just more than 90° to just under 180°. The braiding angle 506 can be an acute angle or an obtuse angle. In some embodiments, the braiding angle 506 is between about 90° and about 180°, between about 120° and about 180°, between about 150° and about 180°, between about 160° and about 180°, between about 170° and about 180°, between about 160° and about 170°, between about 165° and about 175°, combinations thereof, and the like. In some embodiments, the closer the braiding angle 506 is to 180°, the greater the radial strength of the stent 500. The device 500 with greater radial strength can help keep a fistula (e.g., formed as described herein) open or patency. Other factors can also affect radial strength, such as filament 502 diameter, filament 502 material, number of filaments 502, etc.

[0173] The filaments 502 may all be identical, or some of the filaments 502 may have different parameters (e.g., material, size, combinations thereof, and the like). In some embodiments, some of the filaments 502 include a shape memory material (e.g., including nitinol), while other filaments 502 include another material (e.g., including aramid fibers (e.g., ), Biocompatible polymers, etc.). Shape memory materials can provide mechanical structure, while other materials can provide low porosity (e.g., by being thick in the dimensions of the sidewalls).

[0174] Fig.25B 5 is a schematic side view of yet another example embodiment of a prosthesis 520. The prosthesis or stent or device 520 includes and / or consists essentially of a first plurality of filaments 522 woven together into a first woven structure and a second plurality of filaments 524 woven together into a second woven structure. The stent 520 may be free of graft material, as described in further detail herein. The first plurality of filaments 522 may be similar to the first plurality of filaments 522 and the second plurality of filaments 524. Fig.25A In some embodiments, filaments 522 may lack sufficient radial force to maintain fistula opening and / or adhere to the sidewalls of an artery and / or vein. In some such embodiments, filaments 524 may serve as a supplemental support structure that provides radial force. Filaments 524 may be radially outward of filaments 522 (e.g., as in Fig.25B ), radially inward filaments 522, and / or integrated with filaments 522 (e.g., so that the first and second woven structures are not easily separated). Filaments 524 can be the same or different materials as filaments 522, the same or different thicknesses as filaments 522, etc., and / or filaments 524 can be woven using the same or different parameters (e.g., braiding angles) as filaments 522, resulting in filaments 524 having greater radial forces. Filaments 524 can be coupled to filaments 522 (e.g., in a single deployable stent 520) or deployed separately. For example, if filaments 524 are deployed and then filaments 522 are deployed, filaments 524 can prop open fistulas and allow filaments 522 to expand in the lumen established by filaments 524 without substantial counterforce. For another example, if filaments 522 are deployed and then filaments 524 are deployed, filaments 524 can act as an expansion force on a portion of filaments 522 when an expansion force is needed.

[0175] Despite Fig.25B 520 is illustrated as including a second woven structure, but the supplemental support structure may additionally or alternatively include a helical coil, a cut hypotube, combinations thereof, and the like. The determination of the porosity of the prosthesis 520 may be primarily based on the porosity of the first woven structure, such that the supplemental support structure may be primarily designed to provide radial force (e.g., sufficient to keep the fistula open or patent).

[0176] Although illustrated as being consistent or substantially consistent across the length of stent 500, the parameters of stent 500 and filaments 502 may vary across stent 500, such as with respect to Fig.25C Uniformity may reduce manufacturing costs, reduce the need for precise placement, and / or have other advantages. Non-uniformity may allow specialization or customization for specific properties and / or functions along different lengths, and / or have other advantages.

[0177] Fig.25C 540 is a schematic side view of yet another example embodiment of a prosthesis 540. The prosthesis or stent or device 540 includes and / or consists essentially of a plurality of filaments 542 woven together into a woven structure. The stent 540 may be free of graft material, as described in further detail herein. The stent 540 includes a first longitudinal segment or section or portion 544 and a second longitudinal segment or section or portion 546. Porosity (e.g., as in Fig.25B ), braid angle, braid type, filament 542 parameters (e.g., diameter, material, etc.), the presence of supplemental support structures (e.g., supplemental support structures 544), stent diameter, stent shape (e.g., cylindrical, frustoconical), combinations thereof, etc., can be different between the first longitudinal segment 524 and the second longitudinal segment 546. The porosity can be changed depending on the purpose of certain portions of the stent 540. For example, the first longitudinal segment 544, which can be configured for placement in an artery and fistula, can have a low porosity (e.g., less than about 50%, as shown in FIG. Fig.25A The stent 500 described herein may have a second longitudinal segment that may be configured for placement in a vein and may have a higher porosity to increase flexibility and wall attachment.

[0178] In some embodiments, the stent comprises a first longitudinal segment comprising and / or consisting essentially of a low-porosity woven member configured to divert flow from an artery into a fistula and having no supplemental support structure, a second longitudinal segment comprising and / or consisting essentially of a low-porosity woven member configured to divert blood flow through a fistula and comprising a supplemental support structure configured to prop open a fistula, and a third longitudinal segment comprising and / or consisting essentially of a low-porosity woven member configured to divert flow from a fistula into a vein. In some such embodiments, the first longitudinal segment may be configured to Fig.25A The bracket 500, and the third longitudinal section can be configured as Fig.25A Bracket 500 or Fig.25C The bracket 540.

[0179] The difference between the first longitudinal segment 544 and the second longitudinal segment 546 can be imparted during manufacturing (e.g., due to braiding parameters, shape setting, etc.) and / or in the field (e.g., during and / or after deployment (e.g., by stent packaging)).

[0180] Other variations between the first longitudinal segment 544 and the second longitudinal segment 546 as described herein (e.g., including laser cut portions, additional longitudinal segments, etc.) are also possible. In some embodiments, the stent comprises a first longitudinal segment comprising and / or consisting essentially of a low-porosity woven member configured to divert flow from an artery into a fistula, a second longitudinal segment comprising and / or consisting essentially of a low-porosity laser-cut portion configured to be placed in a fistula to divert blood through the fistula and / or prop up a fistula, and a third longitudinal segment comprising and / or consisting essentially of a low-porosity woven member configured to divert flow from a fistula into a vein. In certain such embodiments, the first longitudinal segment may be configured to Fig.25A The bracket 500, and the third longitudinal section can be configured as Fig.25A Bracket 500 or Fig.25C The bracket 540.

[0181] Fig. 27 An example embodiment of a prosthesis 720 is schematically illustrated and described below with respect to Fig. 27 The prosthesis 720 is further described in detail in the anatomy of FIG. The prosthesis 720 includes a first longitudinal segment 722, a second longitudinal segment 724, and a third longitudinal segment 726 between the first longitudinal segment 722 and the second longitudinal segment 724. The porosity of the prosthesis 720 can allow fluid to flow substantially through the lumen of the prosthesis 720 without substantially perfusing through the sidewalls, for example due to the low porosity woven structure, even when there is a substantial lack of graft material.

[0182] In embodiments where the prosthesis 720 is used in a peripheral vascular system, the first longitudinal segment 722 may be described as an arterial segment, the second longitudinal segment 724 may be described as a venous segment, and the third longitudinal segment 726 may be described as a transition segment. The first longitudinal segment 722 is configured to attach to the sidewall of the artery 700 or another body lumen. For example, for some peripheral arteries, the first longitudinal segment 722 may have an expanded diameter between about 2 mm and about 4 mm (e.g., about 3 mm). The second longitudinal segment 724 is configured to attach to the sidewall of the vein 702 or another body lumen. For example, for some peripheral veins, the second longitudinal segment 724 may have an expanded diameter between about 5 mm and about 7 mm (e.g., about 6 mm). In some embodiments, instead of attaching to the sidewall of the vein 702 as in Fig. 27 , the second and third longitudinal segments 724, 726 may have a frusto-conical shape that tapers from a smaller diameter of the first longitudinal segment 722 to a larger diameter.

[0183] The length of the prosthesis 720 can be configured or sized to anchor the prosthesis 720 in the artery 700 and / or vein 702 (e.g., sufficient to block or prevent longitudinal movement or migration of the prosthesis 720) and span the interstitial tissue T between the artery 700 and the vein 702. For example, for some peripheral arteries, the length of the first longitudinal segment 722 in the expanded or deployed state can be between about 20 mm and about 40 mm (e.g., about 30 mm). For another example, for some peripheral veins, the length of the second longitudinal segment 724 in the expanded or deployed state can be between about 10 mm and about 30 mm (e.g., about 20 mm). For yet another example, for some peripheral vascular systems, the length of the third longitudinal segment 726 in the expanded or deployed state can be between about 5 mm and about 15 mm (e.g., about 10 mm). The total length of the prosthesis 720 in the expanded or deployed state can be between about 30 mm and about 100 mm, between about 45 mm and about 75 mm (e.g., about 60 mm). Although the interstitial tissue T is illustrated as being approximately 2 mm thick, other dimensions are possible, depending on the specific anatomy of the deployment site.Other dimensions of the prosthesis 720, first longitudinal section 722, and / or second longitudinal section 724, for example as described herein, are also possible.

[0184] The third longitudinal segment 726 comprises a truncated cone or conical shape that expands from the smaller diameter of the first longitudinal segment 722 to the second longitudinal segment 724. The transition points between the longitudinal segments 722, 724, 726 may be distinct or not. For example, the transition segment may be considered to include a portion of the first longitudinal segment 722 and the third longitudinal segment 726, or the third longitudinal segment 726 may be considered to include a cylindrical portion having the same diameter as the first longitudinal segment 722. The longitudinal segments 722, 724, 726 may differ in the shapes and sizes described above, and / or in other ways (e.g., materials, types, etc.). For example, one or more portions may be cylindrical, truncated cone, etc., as in Fig.12 , Fig.13 and Fig. 27 Illustrated in and described in this article.

[0185] The first longitudinal section 722 and / or the third longitudinal section 726 can include relatively high radial forces, for example, configured to keep fistulas open, while the second longitudinal section 724 can include relatively low radial forces. In some embodiments, the first longitudinal section 722 and / or the third longitudinal section 726 include balloon expandable stents, woven stents with high braiding angles, and / or the like. In some embodiments, the second longitudinal section 724 includes self-expanding stents, woven stents with low braiding angles, and / or the like. Laser cutting stents, woven stents, different cutting patterns, different weaving patterns, and combinations of the like are further described in detail herein. In some embodiments, the longitudinal sections 722, 724, 726 can be integrated or separated. The second longitudinal section 724 can be relatively soft, for example, include relatively low radial forces, which can help the second longitudinal section 724 to bend with the anatomical structure during the pulsation of blood flow.

[0186] In some embodiments, the second longitudinal segment 724 and / or the third longitudinal segment 726 may contain some graft material (e.g., containing silicone). The graft material may block or prevent blood flow through the sidewalls of the prosthesis 720, and / or may be used to carry drugs. For example, depending on the purpose of the graft material, the graft material may or may not block or substantially block the micropores of multiple portions of the prosthesis 720.

[0187] The proximal and / or distal ends of the prosthesis 720 can be atraumatic, for example, including terminal treatments, low braid angles, small filament diameters, combinations thereof, and the like.

[0188] The radial strength or compressive strength of the stent, stent graft, or first end, second end, middle portion, or sub-portions thereof can be between about 0.1 N / mm and about 0.5 N / mm, between about 0.2 N / mm and about 0.5 N / mm, between about 0.3 N / mm and about 0.5 N / mm, between about 0.1 N / mm and about 0.3 N / mm, between about 0.1 N / mm and about 0.2 N / mm, between about 0.2 N / mm and about 0.5 N / mm, between about 0.2 N / mm and about 0.3 N / mm, or between about 0.3 N / mm and about 0.5 N / mm.

[0189] Certain parameter values ​​of a stent, stent graft, or first end, second end, middle portion, or sub-portion thereof can be associated (e.g., proportional). For example, the thickness of a strut or filament to the diameter of the device portion containing the strut or filament can be between about 1:10 and about 1:250, between about 1:25 and about 1:175, or between about 1:50 and about 1:100. For another example, the length of a device or portion thereof to the diameter of the device or portion thereof can be between about 1:1 and about 50:1, between about 5:1 and about 25:1, or between about 10:1 and about 20:1.

[0190] Parts of the device may include radiopaque materials. For example, the filaments and / or struts of a stent, stent graft, or first end, second end, middle portion, or sub-portion thereof may include titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, combinations thereof, and the like (e.g., at least partially made thereof). For another example, the filaments and / or struts of a stent, stent graft, or portion thereof may include a material having a density greater than about 9 g / cm3 (e.g., at least partially made thereof). A separate radiopaque marker may be attached to certain components of the device. For example, a radiopaque marker may be added to the proximal end of the device or its components (e.g., the proximal end component of the middle portion, the proximal end component of the distal portion), the distal end of the device or its components (e.g., the distal end component of the middle portion, the distal end component of the proximal portion), and / or other components. For example, radiopaque markers between the ends of the device may be used to demarcate transitions between materials, portions, etc. The radiopaqueness may vary across 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).

[0191] In some embodiments, the device comprises a polymer tube and no support structure is provided.The middle portion of such a device may be relatively more flexible than the end portions by, for example, reducing the wall thickness of the polymer tube in the middle portion.

[0192] When a mesh or other support structure is provided in conjunction with a polymeric tube, the support structure may be located around the outside of the tube, in the inner bore of the tube, or embedded in the tube wall. More than one support structure may be provided, in which case each support structure may have a different position relative to the tube.

[0193] One or both of the ends of the device may include an anchoring element such as a hook, protuberance or barb configured to grab or grip the inner wall of the blood vessel. In the absence of an anchoring element, the radial force of the expanded end may be sufficient to grab or grip the inner wall of the blood vessel.

[0194] There need not be a clearly defined transition between the middle portion and the end portions. For example, the mesh type, material, wall thickness, flexibility, etc. may change gradually from the end portions towards the middle portion or from the middle portion towards the end portions.

[0195] For example, as described with respect to devices 134, 140, the flexibility of the device can increase gradually when moving from the end toward the middle portion. The change in flexibility can be due to changes 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 along the entire length of the support structure (e.g., stent), or along certain portions of the support structure (e.g., along the entire end, along the entire middle portion, along one end and the middle portion but not along the other end, etc.).

[0196] Although the device described herein can be particularly suitable for use as a shunt through a blood vessel in a percutaneous procedure, the device can be used in many other medical applications. For example, the device can be used in angioplasty to treat an occluded blood vessel with a tortuous or kinked path, or wherein the vessel may be subjected to deflection or deformation at or near the position of the stent. For example, the stent can also be used to repair damaged blood vessels in an aortic transplantation procedure or after a perforation during a percutaneous procedure. In some such cases, in response to the movement of the vessel, the middle portion of the device can allow the device to conform to the shape of the blood vessel and deform, and have a reduced risk of fatigue failure, while keeping the end fixed or anchored in place. For another example, the device can be used to form a shunt between a healthy artery and a healthy vein for dialysis entry and / or entry of drug administration (for example, intermittent injection of cancer treatment, which may damage the vessel).

[0197] Refer again Figure 4 and Figure 7 , occlusive material 251 can be used to help inhibit or prevent the reversal of arterial blood flow. As will now be described in further detail, additional or other methods and systems can be used to inhibit or prevent the reversal of arterial blood flow, or, in other words, to inhibit or prevent arterial blood flow that now flows into a vein from flowing in the normal pre-procedure direction of blood flow in the vein, thereby causing oxygenated blood to bypass downstream tissues such as the foot.

[0198] In the absence of treatment, peripheral vascular disease (PVD) may progress to critical limb ischemia (CLI), which is characterized by profound chronic pain and massive tissue loss that limits revascularization options and frequently leads to amputation. CLI is estimated to have an incidence of approximately 50-100 per 100,000 per year and is associated with a mortality rate as high as 20% at 6 months after onset.

[0199] Interventional radiologists have actively attempted to treat CLI by attempting to open chronic total occlusions (CTOs) or by bypassing CTOs in the subintimal space using products such as the Medtronic-Pioneer catheter, which tunnels a wire into the subintimal space near the CTO and then attempts to re-enter the vessel distal to the occlusion. Once the wire is in place, the user can optionally create a wider pathway and then place a stent to provide a bypass catheter across the occlusion. If the wire is able to pass the occlusion, conventional approaches to treating PAD such as percutaneous transluminal angioplasty (PTA), stenting, and drug eluting balloons (DEB) can also or alternatively be used in CLI treatment.

[0200] From amputee-coalition.org, here are some statistics on the CLI problem:

[0201] Nearly two million people in the United States suffer from limb loss.

[0202] Among those who endure limb loss, the main causes are:

[0203] Vascular disease (54%) (including diabetes and peripheral arterial disease (PAD)),

[0204] Trauma (45%), and

[0205] Cancer (less than 2%).

[0206] In the United States, approximately 185,000 amputations occur each year.

[0207] In 2007, hospital costs related to amputations totaled more than $6.5 billion.

[0208] Survival rates after amputation vary based on many factors. Those who have an amputation due to vascular disease (including PAD and diabetes) face 30-day mortality rates reported to be between 9% and 15% and long-term survival rates of 60% at 1 year, 42% at 3 years, and 35%-45% at 5 years.

[0209] Almost half of people who lose a limb to vascular disease will die within 5 years. This is higher than the 5-year mortality rate experienced by people with colorectal cancer, breast cancer, and prostate cancer.

[0210] Up to 55% of people with diabetes who have a lower limb amputation will require a second leg amputation within 2 to 3 years.

[0211] Since the early twentieth century, CLI has been surgically treated by open-leg venous arterialization. Over the years, many small series of clinical trials using such open-leg surgical approaches have been published, as summarized by Lu et al. in a 2006 meta-analysis article entitled "Meta-analysis of the clinical effectiveness of venous arterialization for salvage of critically ischemic limbs" in European Journal of Vascular and Endovascular Surgery, Volume 31, Pages 493-499. The article has the following results and conclusions:

[0212] ·result:

[0213] A total of 56 studies were selected for comprehensive review. No randomized controlled trials (RCTs) were identified. Seven patient series matching the selection criteria included 228 patients. Full 1-year foot preservation was 71% (95% CI: 64%-77%) and 1-year secondary patency was 46% (95% CI: 39%-53%). Most patients who avoided major amputation experienced successful wound healing, absence of rest pain, and absence of major complications.

[0214] ·in conclusion:

[0215] Based on limited evidence, venous arterialization is considered a viable alternative before major amputation in patients with “inoperable” chronic critical lower limb ischemia.

[0216] Among other diseases described herein, the methods and systems described herein can be used to establish an arteriovenous (AV) fistula in the below-the-knee (BTK) vasculature using an endovascular minimally invasive surgical approach. Such methods can be suitable for patients who: (i) have a clinical diagnosis of symptomatic critical limb ischemia as defined by Rutherford 5 or 6 (severe ischemic ulcers or symptomatic gangrene); (ii) have been evaluated by a vascular surgeon and interventionist and determined that surgical or endovascular treatment is not possible; and / or (iii) have a clear indication for major amputation.

[0217] In some embodiments, the system or kit optionally includes one or more of the following components: a first ultrasound catheter (e.g., an arterial catheter, a transmitting catheter containing a needle, etc.); a second ultrasound catheter (e.g., a venous catheter, a target catheter, etc.); and a prosthesis (e.g., a nitinol stent graft coated in a delivery system (e.g., a 7Fr (approximately 2.3mm) delivery system)). The system or kit optionally further includes an ultrasound system, a control system (e.g., a computer). Some users may already have a suitable ultrasound system that can be connected to (one or more) ultrasound catheters. The catheters and prostheses described above can be used in the system or kit, and details of other, additional and / or modified possible components are described below.

[0218] Fig.14A 1 is a schematic side cross-sectional view of an example embodiment of an ultrasound emitting catheter 170, which includes a needle 172 (e.g., a first ultrasound catheter, an arterial catheter (e.g., if the needle extends from an artery into a vein), a venous catheter (e.g., if the needle extends from a vein into an artery)). The catheter 170 is placed into the artery, with the needle 172 inside the lumen of the catheter 170 in a retracted state. The catheter 170 can be advanced over a guidewire (e.g., a 0.014 inch (approximately 0.36 mm) guidewire) and / or placed through a sheath in an artery (e.g., a femoral artery) and advanced until the point of complete occlusion of the artery (in the tibial artery). The catheter 170 includes a handle 174 including a pusher ring 176. Longitudinal or distal advancement of the pusher ring 176 can advance the needle 172 out of the lumen of the catheter 170, out of the artery and into the vein, as described herein. Other advancement mechanisms for the needle 172 are also possible (e.g., rotating, motorized, etc.). Before, after, and / or during advancement of needle 172, a guide wire (e.g., a 0.014 inch (approximately 0.36 mm) guide wire) may be placed through needle 172 (e.g., as described with respect to Figure 3 The guide wire 14 is described above), and the guide wire can be referred to as a crossing wire.

[0219] Fig. 14B It is within circle 14B Fig.14A FIG. 1 is an enlarged schematic side cross-sectional view of a distal portion of an ultrasound transmitting catheter 170 of FIG. After advancement or firing, the needle 172 extends radially outward from the lumen 173 of the catheter 170. In some embodiments, the lumen 173 ends proximal to the ultrasound transmitting device 178. The needle 172 can extend along a path that is aligned with (e.g., parallel to) the path of a directed ultrasound signal emitted by the ultrasound transmitting device 178. Fig. 14B Also shown is a lumen 175 which may be used to accommodate a guidewire for tracking catheter 170 to a desired location.

[0220] Fig.15A is a schematic side view of an example embodiment of an ultrasound target catheter 180 (eg, a second ultrasound catheter, an arterial catheter (eg, if a needle extends from a vein into an artery)), a venous catheter (eg, if a needle extends from an artery into a vein). Fig. 15B It is within circle 15B Fig.15A An enlarged schematic side cross-sectional view of an ultrasound target catheter 180 is shown. Fig. 15C Is within circle 15C Fig.15A 1. An enlarged schematic side cross-sectional view of an ultrasound target catheter 180. The catheter 180 can be advanced over a guidewire (e.g., a 0.014 inch (approximately 0.36 mm) guidewire) and / or placed through a sheath in a vein (e.g., a femoral vein) and advanced until close to and / or parallel to the distal end of the catheter 170 and / or the point of occlusion in the artery (e.g., in the tibial vein). The catheter 180 includes an ultrasound receiving transducer 182 (e.g., an omnidirectional ultrasound receiving transducer) that can act as a target in the vein for aligning the needle 172 of the catheter 170. The catheter 180 can stay in place or remain stationary or substantially stationary while the catheter 170 is rotated or moved longitudinally to obtain a good or optimal ultrasound signal indicating that the needle 172 is aligned with the catheter 180 and in the direction of the catheter 180.

[0221] The catheters 170, 180 can be connected to an ultrasonic transceiver that is connected to and controlled by a computer running transceiver software. As described in further detail herein, the catheter 170 includes a flat or designated ultrasonic transmitter 178 that is configured to transmit an ultrasonic signal having a low angular spread or a tight beam (e.g., a small beam width) in the direction of the needle 172 path after being advanced from the lumen 173 of the catheter 170. The catheter 180 includes an omnidirectional (360 degree) ultrasonic receiver 182 that is configured to act as a target for the ultrasonic signal emitted by the directional transmitter 178 of the catheter 170. The catheter 170 is rotated until a peak ultrasonic signal is displayed, which indicates that the needle 172 is aligned with the catheter 180, so that after the needle 172 is extended (e.g., by longitudinally advancing the ring 176 of the handle 174), the needle 172 can leave the artery in which the catheter 170 resides, pass through interstitial tissue, and enter the vein in which the catheter 180 resides.

[0222] Fig.16 is an example embodiment of a diagram for detecting catheter alignment, as may be displayed on a display device of an ultrasound system (eg, a screen of a laptop computer, tablet computer, smartphone, combinations thereof, and the like). Fig.16The diagram in FIG. 1 shows that the signal originating from the transmitting catheter in the artery has been received by the receiving catheter in the vein. The second frequency envelope from the right is the received signal. The distance from the left side of the illustrated screen to the leading edge of the second frequency envelope can represent the distance between the catheters. The operator can move the catheter in the artery rotationally and longitudinally, for example, until the second envelope is maximal, which indicates that the catheter is correctly oriented.

[0223] Fig.17 is a schematic side view of an example embodiment of a prosthesis (eg, stent, stent graft) delivery system 190. In some embodiments, the delivery system 190 is a 7 Fr (approximately 2.3 mm) delivery system. Fig.18 is a schematic side view of an example embodiment of a prosthesis (eg, stent, stent graft) 200. Fig.17 In the embodiment of the present invention, a prosthesis (e.g., prosthesis 200, other prostheses described herein, etc.) is in a compressed or curled state near the distal end 192 of the delivery system 190. In some embodiments, the prosthesis 200 includes a shape memory stent covered with a graft material, such as described above. Once the traversing wire extends from the artery to the vein, the delivery system 190 can be advanced on the traversing wire, such as due to being advanced through the needle 172 as described herein. The prosthesis 200 can be deployed from the delivery system 190, such as by squeezing the trigger handle 194 of the delivery system 190, retracting the outer cover sheath proximally and / or advancing the prosthesis 200 distally. The prosthesis 200 can establish a flow path between the artery and the vein and through the interstitial tissue. Other types of delivery systems and prostheses are also possible.

[0224] Refer again Fig.17, some non-limiting example dimensions of the delivery system 190 are provided. The travel distance 196 of the trigger handle 194 can be, for example, between about 0.4 inches (about 1 cm) and about 12 inches (about 30 cm), between about 1 inch (about 2.5 cm) and about 8 inches (about 20 cm), or between about 2 inches (about 5 cm) and about 6 inches (about 15 cm) (e.g., about 2 inches (about 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 to be deployed (e.g., in the radially expanded state). In some embodiments, a transmission mechanism or other mechanism can be employed to reduce the travel distance 196 of the trigger handle 194 to be less than the length of the prosthesis 200 to be deployed (e.g., in the radially expanded state). For example, the distance 196 can be adjusted based on at least one of the following: the length of the prosthesis 200 to be deployed, the degree of foreshortening of the prosthesis 200 to be deployed, the deployment mechanism (e.g., whether the outer sheath is retracted proximally, whether the prosthesis 200 is pushed forward distally, or both, 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, between about 40 inches (about 1020 mm) and about 50 inches (about 1270 mm), between about 46 inches (about 1170 mm) and about 47 inches (about 1190 mm), or between about 46.48 inches (about 1180 mm) and about 46.7 inches (about 1186 mm). The total length 198 of the delivery system 190 from the proximal end to the distal end can be, for example, between about 40 inches (about 1000 mm) and about 60 inches (about 1500 mm). The lengths 197, 198 can be adjusted, for example, based on at least one of the following: the length of the prosthesis 200 to be deployed, the degree of foreshortening of the prosthesis 200 to be deployed, the height of the patient, the location of the occlusion being treated, combinations thereof, and the like. In some embodiments, spacing the trigger handle 194 from the vascular access point, for example, between about 10 cm and about 30 cm (e.g., at least about 20 cm) can advantageously provide a user with simpler handling or management. In certain such embodiments, the length 197 can be between about 120 cm and about 130 cm (e.g., for an antegrade approach) or between about 150 cm and about 180 cm (e.g., for a contralateral approach).

[0225] Refer again Fig.18, some non-limiting example dimensions of the prosthesis 200 are provided, depending on the environment at least in the compressed state. The thickness 201 of the structural struts can be, for example, between about 0.05 mm and about 0.5 mm or between about 0.1 mm and about 0.2 mm (e.g., about 0.143 mm). The spacing 202 between the struts of the structural struts can be, for example, between about 0.005 mm and about 0.05 mm or between about 0.01 mm and about 0.03 mm (e.g., about 0.025 mm). The thickness 203 of the connecting struts can be, for example, between about 0.05 mm and about 0.5 mm or between about 0.1 mm and about 0.2 mm (e.g., about 0.133 mm). The longitudinal length 204 of the structural member can be, for example, between about 1 mm and about 5 mm or between about 2.5 mm and about 3 mm (e.g., about 2.8 mm). The longitudinal length 205 between the structural components can be, for example, between about 0.25 mm and about 1 mm or between about 0.5 mm and about 0.6 mm (e.g., about 0.565 mm). The length 206 of the struts within the structural components (including all portions that are wound back and forth) can be, for example, between about 25 mm and about 100 mm or between about 65 mm and about 70 mm (e.g., about 67.62 mm). The total longitudinal length of the prosthesis 200 can be, for example, between about 25 mm and about 150 mm or between about 50 mm and about 70 mm (e.g., about 62 mm). As described herein, many laser cut stents, woven stents, and combinations thereof, including various sizes, are possible. The struts described herein can include wires or filaments or portions that are not cut from a hypotube or plate.

[0226] The proximal and / or distal ends of the prosthesis 200 may optionally include a ring 210. For example, the ring 210 may help anchor the prosthesis 200 in an artery and / or vein. The circumferential width 211 of the ring 210 may, for example, be between about 0.25 mm and about 1 mm or between about 0.5 mm and about 0.75 mm (e.g., about 0.63 mm). For example, the longitudinal length 212 of the ring 210 may be between about 0.25 mm and about 2 mm or between about 0.5 mm and about 1 mm (e.g., about 0.785 mm). In some embodiments, the ratio of the total length of the prosthesis 200 to the longitudinal length 212 of the ring 210 may be between about 50:1 and about 100:1 (e.g., about 79:1). The dimensions 211, 212 of the ring 210 may be adjusted, for example, based on at least one of the following: strut thickness, diameter of the prosthesis (e.g., relative to the vessel), total length of the prosthesis, material, shape setting properties, combinations thereof, and the like.

[0227] Fig.19is a schematic side view of another example embodiment of a prosthesis 220. Prosthesis 200 can have the shape of prosthesis 220, such as in a radially expanded state (eg, after deployment from delivery system 190). Fig.19 An example shape of a prosthesis 220 is shown that includes a first portion 221 and a second portion 225. The first portion 221 has a generally cylindrical or columnar shape having a length 222 between about 15 mm and about 25 mm (e.g., about 21 mm) and a diameter 223 between about 2.5 mm and about 5 mm (e.g., about 3.5 mm). The second portion 225 has a generally frustoconical or frustoconical shape having a length 226 between about 30 mm and about 50 mm (e.g., about 41 mm) and a maximum diameter 227 between about 4 mm and about 10 mm, between about 4 mm and about 7 mm (e.g., about 5.5 mm), etc. The angle of the taper of the second portion 225 away from the first portion 221 can be between about 0.02 degrees and about 0.03 degrees (e.g., about 0.024 degrees).

[0228] Further details regarding prostheses that may be used in accordance with the methods and systems described herein are described in U.S. Patent Application No. 13 / 791,185, filed on March 8, 2013, which is hereby incorporated by reference in its entirety.

[0229] Figures 20A-20H An example embodiment of a method of achieving retrograde perfusion is schematically illustrated. The procedure will be described with respect to the peripheral vascular system such as the calf, but may also be adapted to other body cavities (e.g., cardiac, other peripheral, etc.). Certain steps such as anesthesia, incision details, suturing, etc. may be omitted for clarity. In some embodiments, the procedure may be performed from a vein to an artery (e.g., using an intravenous catheter from below).

[0230] Access to the femoral artery and femoral vein is obtained. For example, using the Seldinger technique, an introducer sheath (e.g., 7Fr (approximately 2.3mm)) is inserted into the femoral artery and an introducer sheath (e.g., 6Fr (approximately 2mm)) is inserted into the femoral vein. A guide wire (e.g., 0.014 inch (approximately 0.36mm), 0.035 inch (approximately 0.89mm), 0.038 inch (approximately 0.97mm)) is inserted through the introducer sheath in the femoral artery and guided into the distal portion of the diseased artery 300 posterior to the tibial or anterior to the tibial. A second guide wire (e.g., 0.014 inch (approximately 0.36mm), 0.035 inch (approximately 0.89mm), 0.038 inch (approximately 0.97mm)) or a snare is inserted through the introducer sheath in the femoral vein. In an embodiment using a snare, the third guide wire, the fourth guide wire, etc. described herein are accurate - even if the numbering may not be continuous.

[0231] 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 can be guided under ultrasound. In some embodiments, contrast agent can be injected into the saphenous vein toward the foot (retrograde), and the contrast agent will then flow 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.

[0232] The target vein can be accessed proximally and distally (e.g., several inches or centimeters) below where the launching catheter 310 is likely to reside. In some embodiments, the target vein can be in the ankle. Once the venous access needle is in the vein, a third guidewire (or "second" guidewire, in which case a snare is used instead of the second guidewire) is inserted through the venous access needle and advanced antegrade in the target vein until it reaches the femoral vein. This method of entry can advantageously reduce problems caused by retrograde advancement of wires through venous valves, which are described in further detail below. For example, fluoroscopic guidance is used to snare the third guidewire and pull it through the femoral vein sheath. The target catheter 320 is inserted into the femoral vein sheath over the captured third guidewire. The target catheter 320 is advanced into the venous system over the third guidewire until the target catheter is adjacent to the guidewire in the distal portion of the diseased artery posterior or anterior tibial and / or parallel to the guidewire and / or adjacent to the occlusion 304, such as Fig. 20A As shown in .

[0233] In some embodiments, the third guidewire can include an ultrasound receiving transducer (e.g., omnidirectional) mounted to provide a target for the signal emitted by the transmitting catheter 310, or the target catheter 320 can be advanced over the third guidewire, either of which can allow for omission of certain techniques (e.g., femoral vein entry, introduction of a venous introducer sheath, insertion of a second guidewire, antegrade advancement of the third guidewire to the femoral vein, capture of the third guidewire, advancement of the target catheter 320 over the third guidewire).

[0234] In some embodiments, the PTV can be accessed directly, for example using ultrasound, which can allow the target catheter 320 to be placed directly into the PTV, for example using a small sheath, which can allow certain techniques to be omitted (e.g., femoral vein entry, introduction of a venous introducer sheath, insertion of a second guidewire, antegrade advancement of a third guidewire until the femoral vein).

[0235] In some embodiments, catheter 320 is not an over-the-wire catheter, but includes a guidewire and an ultrasound receiving transducer (e.g., omnidirectional). Catheter 320 can be inserted as a third guidewire, as a second guidewire, or as a guidewire through a small sheath when directly entering the PTV as discussed above.

[0236] Ultrasonic transducers typically include two electrodes comprising surfaces separated by a vibrating ceramic. An incoming or received ultrasonic signal wave can be coupled into a length-extending pattern such as Fig.21 As shown in . Fig.21 350. It is a schematic perspective view of an example embodiment of an ultrasound receiving transducer 350. If the proximal end or top end 352 of the transducer 350 and the distal end or bottom end 354 of the transducer are conductive and electrically connected to the wire, the transducer can receive ultrasonic signals. In some embodiments, the length 356 of the transducer 350 is between about 0.1mm and about 0.4mm (e.g., about 0.25mm). In some embodiments, the overlapping length 358 of the transducer 350 is between about 0.1mm and about 0.3mm (about 0.2mm). In some embodiments, the diameter of the transducer 350 is similar, substantially similar or identical to the guide wire to which it is mounted. In some embodiments, a row or a series of laminated materials can enhance the signal receiving capability of the transducer 350.

[0237] In some embodiments, a guidewire including an ultrasound receiving transducer may include a piezoelectric film (eg, including plastic) that may enhance the signal receiving capabilities of the transducer. Fig. 22 is a schematic cross-sectional view of another example embodiment of an ultrasound receive transducer 360 . Fig. 22The ultrasonic receiving transducer 360 shown in FIG. 3 includes an optional inner cavity 368. The ultrasonic receiving transducer 360 includes a series of layers 362, 364, and 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. The thickness of layer 366 may be between about 25 micrometers (μm or micrometers) and about 250 μm (e.g., at least about 50 μm).

[0238] The launch catheter 310 is advanced over the guidewires in the femoral and tibial arteries near and proximal to the occlusion 304, as shown in FIG. Fig. 20B . The catheter 310 may be closer to the occlusion 304, depending on the suitability of that portion of the anatomy for a retrograde perfusion procedure. In some embodiments, the catheter 310 may be disposed in a distal portion of the posterior tibial artery or the anterior tibial artery, such as near the catheter 320. In some embodiments, the catheter 310 may be disposed within a few inches or centimeters of the ankle.

[0239] The transmitting catheter 310 emits a directional ultrasound signal. Fig. 20C The launch catheter 310 is rotated and moved longitudinally as shown by arrows 311, 312 until a signal is received by the target catheter 320. Once the signal is received, indicating alignment, such that extension of the needle from the launch catheter 310 will result in successful entry into the vein, the traversing needle 314 is pushed out of the catheter 310, out of the tibial artery 300 and into the tibial vein 302, as shown in FIG. Fig.20D The accuracy of placement of the transverse needle 314 to form a fistula between the artery 300 and the vein 302 can be confirmed, for example, using contrast agents and fluoroscopy.

[0240] In some embodiments, the ultrasound signal can be used to determine the distance between the artery 300 and the vein 302. 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 indication of the distance between the catheters.

[0241] Refer again Fig.16 , the display device can graphically show the signal alignment peak to allow the user to determine the alignment position. In some embodiments, the signal alignment can change color above or below a threshold, such as from red to green. In some embodiments, for example, an audio signal can be emitted when the alignment signal crosses a threshold, which can allow the user to stay focused on the patient rather than monitoring the screen substantially continuously.

[0242] In some embodiments, a horizontal line on the screen may move up during the procedure to indicate the maximum signal value or peak value reached at that point. This line may be referred to as a "peak hold." If a larger signal value is reached, the horizontal line moves to match that higher value. If no manipulation is able to raise the peak value above the horizontal line, then that may indicate maximum alignment. If the signal peak drops a certain amount below the horizontal line, then the catheter may have moved and is no longer properly aligned. Because the alignment level represented by the horizontal line has previously been reached during the procedure, the user knows that such an alignment level can be reached by further rotational manipulation and / or longitudinal manipulation.

[0243] A fourth guidewire 316 (e.g., 0.014 inch (approximately 0.36 mm)) (or "third" guidewire, in which case a snare is used instead of the second guidewire) is placed through the lumen of the transverse needle 314 of the catheter 310 and into the tibial vein 302 in a retrograde direction (of the vein 302) toward the foot, as shown in FIG. Fig.20E . External sheath pressure may be applied above the needle traversal point to reduce flow in the artery 300, thereby inhibiting or preventing the formation of a hematoma, and / or to cause venous congestion to facilitate valve penetration. The catheters 310, 320 may be removed, leaving the guidewire 316 in place, extending from the introducer sheath in the femoral artery, through the arterial tree, and into the tibial vein 302.

[0244] Certain techniques for passing the guidewire 316 from the artery 300 to the vein 302 may be used instead of or in addition to the directed ultrasound techniques described herein.

[0245] In some embodiments, a tourniquet can be applied to the leg, which can increase the diameter of the vein. In some embodiments, an occlusive agent (e.g., Figure 4 and Figure 7 As discussed, occluding balloons, etc., can be used to increase the diameter of the vein. For example, venous flow can be reversed, causing the vein to expand. A larger vein diameter can create a larger target for the traversing needle 314, making it easier to enter the vein 300 using the traversing needle 314.

[0246] In some embodiments, a PTA balloon can be used in the target vein, and a needle catheter (e.g., Outback, available from Cordis) can target the PTA balloon under fluoroscopy. The traversing needle 314 can pierce the PTA balloon, and a decrease in the PTA balloon pressure can confirm proper alignment of the traversing needle 314. The PTA balloon can increase the diameter of the vein, creating a larger target for the traversing needle 314, making it easier to enter the vein 300 using the traversing needle 314. A guidewire 316 can be advanced through the traversing needle 314 and into the PTA balloon.

[0247] In some embodiments, the PTA balloon includes a mesh (e.g., a woven mesh) embedded in the polymer of the balloon, for example. When a balloon without such a mesh is punctured, the balloon material may rupture and cause an embolus (e.g., a piece of balloon floating downstream). The mesh can help limit tearing of the balloon material, which can inhibit or prevent the balloon material from causing an embolus.

[0248] In some embodiments, two PTA balloons spaced longitudinally along the axis of the catheter can be used in the target vein, and the needle catheter can target one of the PTA balloons. After piercing one of the PTA balloons by the traversing needle 314, the contrast agent in the well between the PTA balloons can be released because the pierced balloon no longer acts as a dam for the contrast agent. The release of the contrast agent can be monitored using fluoroscopy. The PTA balloons can be on the same catheter or on different catheters.

[0249] In some embodiments, two PTA balloons spaced longitudinally along the axis of the catheter can be used in the target vein, and the needle catheter can target the space or well between the PTA balloons. After piercing the well by the traversing needle 314, the contrast agent in the well can be disturbed. The interference of the contrast agent can be monitored by using fluoroscopy. The PTA balloons can be on the same catheter or on different catheters.

[0250] In some embodiments where the PTA balloon can be used in combination with an ultrasound target in a target vein, the PTA balloon catheter includes a PTA balloon and an ultrasound receiving transducer (e.g., omnidirectional). In some such embodiments, the transmitting catheter 310 can target the PTA balloon under fluoroscopy and / or can target the ultrasound receiving transducer, as described herein. The traversing needle 314 can pierce the PTA balloon, and the pressure reduction of the PTA balloon can confirm the proper alignment of the traversing needle 314. The PTA balloon can increase the diameter of the vein, creating a larger target for the traversing needle 314, making it easier to enter the vein 300 using the traversing needle 314. The guidewire 316 can be advanced through the traversing needle 314 and into the PTA balloon.

[0251] In some embodiments, a LeMaitre device (e.g., UnBalloon TMA Non-Occlusive Modeling Catheter (available from LeMaitre Vascular of Burlington, Massachusetts) can be used in a target vein. In some embodiments, the LeMaitre device can increase the diameter of the vein. A larger vein diameter can create a larger target for the traversing needle 314, making it easier to enter the vein 300 using the traversing needle 314. In some embodiments, the needle 314 can penetrate the LeMaitre device. In some such embodiments, the LeMaitre device can act as a mesh target (e.g., including a radiopaque material visible under fluoroscopy) for the traversing needle 314. The mesh of the LeMaitre device can be radially expanded by advancing the proximal portion of the mesh far away and / or retracting the distal portion of the mesh proximally (e.g., pushing the ends together like an umbrella) and / or by making the mesh self-expanding (e.g., in embodiments where at least some portions of the mesh include a shape memory material). In some embodiments, the LeMaitre device can grip the traversing wire to keep the traversing wire in the target vein as the LeMaitre device approaches.

[0252] In some embodiments, the launch catheter 310 may include a first magnet having a first polarity, and the target catheter 320 may include a second magnet having a second polarity. When the magnets are close enough to move one or both of the catheters 310, 320 by magnetic force, the traversing needle 314 may be advanced to establish a fistula between the artery 300 and the vein 302. In some embodiments, the first magnet may be aligned circumferentially with the traversing needle 314, and / or the launch catheter 310 may be magnetically shielded to provide rotational alignment. In some embodiments, the second magnet may be relatively thin longitudinally to provide longitudinal alignment. In some embodiments, the traversing needle 314 and / or the guidewire 316 may be magnetically pulled from the artery 300 to the vein 302, or vice versa. Some systems may include both ultrasound guidance and magnetic guidance. For example, ultrasound guidance may be used for initial alignment, and magnetic guidance may be used for precise alignment.

[0253] Refer again Figures 20A-20H , the prosthesis delivery system 330 carrying the prosthesis 340 is advanced over the guide wire 316 through the interstitial space between the artery 300 and the vein 300, and then enters the vein 300, as shown in FIG. Fig.20F In some embodiments, a separate PTA balloon catheter (e.g., approximately 2 mm) can be advanced over the guidewire 316 to pre-enlarge the fistula between the artery 300 and the vein 302 prior to introduction of the prosthesis delivery system 330. The use of a PTA balloon catheter can depend on, for example, the radial strength of the prosthesis 340.

[0254] The prosthesis 340 is activated by, for example, operating the trigger handle 194 ( Fig.17 ) is deployed from the prosthesis delivery system 330. In some embodiments, for example, if the prosthesis 340 fails to expand and / or advance, the prosthesis delivery system 330 can be removed and the PTA catheter (e.g., approximately 2 mm) can be advanced over the guidewire 316 to attempt to enlarge or further enlarge the fistula between the artery 300 and the vein 302. The deployment of the prosthesis 340 can then be reattempted (e.g., by self-expansion, balloon expansion, etc.). In some embodiments, the deployment of the prosthesis 340 can reshape the vessel, such as by expanding the diameter of the vessel by at least about 10%, at least about 20%, at least about 30%, or more, between about 0% and about 10%, between about 0% and about 20%, between about 0% and about 30%, or more. In embodiments where the prosthesis 340 is self-expanding, the degree of remodeling can change over time, such as the prosthesis 340 expanding when the vessel expands or the prosthesis 340 contracting when the vessel contracts.

[0255] Once the prosthesis 340 is deployed, as Figure 20G As shown in , a PTA catheter can be used to enlarge the fistula. The diameter of the PTA catheter (e.g., 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 can include (e.g., proximal or distal to the prosthesis 340) a PTA balloon catheter that can be used for one, several, or all of the optional PTA balloon catheter techniques described herein. In embodiments where the prosthesis includes a conical portion, the PTA balloon can include a conical portion. Once the prosthesis 340 is in place, the prosthesis delivery system 330 can be removed, as described herein. Fig. 20H An AV fistula is thus formed between artery 300 and vein 302. Confirmation of the placement of the various catheters 310, 320, 330 and prosthesis 340 may be confirmed under fluoroscopy using contrast injection throughout part or all of the procedure.

[0256] In some embodiments, a marker (e.g., a clip, a lancet, scissors, a pencil, etc.) can be applied to the skin (e.g., adhered to the skin, placed on top of it, etc.) to approximately mark the location of the fistula formed between the artery 300 and the vein 302 by the traversing needle 314 before the deployment of the prosthesis 340. In embodiments where the user uses a sphygmomanometer inflated on the fistula to avoid bleeding, the lack of blood flow can make visualization or even estimation of the fistula site difficult, and the marker can provide such identification. In embodiments where the sending catheter and the receiving catheter are removed after the fistula is formed, the crossing point may be difficult for the user to feel or determine, and the marker can provide such identification. If the fistula is to be enlarged, the midpoint of the enlargement balloon can preferably be aligned with the midpoint of the fistula (e.g., to increase or maximize the hole through the gap zone). In some embodiments, the marker can be visualized under fluoroscopy (e.g., including radiopaque material) to allow the user to see or remember the location of the fistula under fluoroscopy before the deployment of the prosthesis 340.

[0257] Once the prosthesis 340 is in place, an obstacle to blood flow through the vein 302 and into the foot is the valve in the vein. Maneuvering a guidewire through the venous valve may be challenging, for example because the pressure from the artery may not be sufficient to dilate the vein and make the valve incompetent. Applicants have discovered that the venous valve distal to the AV fistula can be disabled or rendered incompetent using one or more of a number of techniques such as a PTA catheter, a stent (e.g., a covered stent, a stent graft, etc.), and a valvulome, as described in further detail below. Disabling the venous valve can allow blood to flow from the femoral artery via retrograde perfusion, retrograde in the vein 302, and retrograde in the vein to the venules and capillaries distal to the venous circulation of the foot to provide oxygenated blood to the foot of a CLI patient.

[0258] In some embodiments, a high pressure PTA balloon catheter can be used to resuscitate venous valvular insufficiency (eg, when inflated to greater than about 10 atm (about 1013 kilopascals (kPa))).

[0259] In some embodiments, one or more stents may be placed across one or more venous valves to cause those valves to become incompletely closed. For example, such a stent should have sufficient radial force to keep the valve open. The stent may forcefully rupture the valve. In some embodiments, the stent comprises a covering or a graft. Some such embodiments are capable of covering the venous side tube. In some embodiments, the stent is bare or has no covering or graft. Some such embodiments are capable of reducing costs. The venous stent may extend along the length (e.g., the entire length) of the vein. For example, in some embodiments, the entire length of the PTV is in line with the covered stent, covering the venous side tube, interfering with the venous valve.

[0260] In some embodiments, the venous stent is separate from the fistula prosthesis. A separate venous stent may allow for more flexibility in some properties such as size (eg, length, diameter), material (eg, with or without a covering or graft), and other properties. Fig.31A An example embodiment of an arteriovenous fistula stent 340 is schematically illustrated as being separated from an example embodiment of a venous stent 342. The venous stent 342 may be spaced apart from the fistula stent 340 (e.g., as in Fig.31A ), close to the fistula stent 340, or overlapping, invaginated, or 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 embodiments where the fistula stent 340 and the venous stent 342 overlap, the placement of the venous stent 342 can first allow the proximal end of the venous stent 342 facing the direction of retrograde blood flow to be covered by the fistula stent 340 to reduce or eliminate blood flow interference that may occur due to the distal end of the venous stent 342. In embodiments where the fistula stent 340 and the venous stent 342 overlap, the placement of the venous stent 342 can secondly pass through the fistula stent 340 so that the two stents 340, 342 can share at least one deployment parameter (e.g., allowing the stent deployment device to be advanced over the same guidewire). The venous stent 342 can be deployed before or after the fistula stent 340. The venous stent 342 can have a length between about 2 cm and about 30 cm (e.g., about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, about 30 cm, ranges between such values, etc.).

[0261] In some embodiments, the venous stent is integrated with the fistula prosthesis. An integrated venous stent may allow for greater flexibility in some properties such as size (eg, length, diameter), material (eg, with or without a covering or graft), and other properties. Fig.31B An example embodiment arteriovenous fistula stent 344 including an integrated venous stent is schematically illustrated. Fig.31CAn example embodiment of a fistula stent 344 including an integrated venous stent is schematically illustrated. The stent 344 includes a first portion 346 configured to anchor in an artery, a second portion 350 configured to anchor in a vein and fill a length of the vein, and a third portion 348 longitudinally between the first portion 346 and the second portion 350. In embodiments where the first portion 346 and the second portion 350 have different diameters (e.g., as in Fig.31C ), the third portion 348 can be tapered. In some embodiments, a portion of the second portion 350 configured to fill a vein has different properties (e.g., diameter, material, radial strength, combinations thereof, and the like) than other portions of the second portion 350. The length of the second segment 350 can be greater than the length of the first segment 346. For example, the second segment 350 can have a length configured to fill a vessel (such as a PTV). The second section 350 can have a length between about 2 cm and about 30 cm (e.g., about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, about 30 cm, ranges between such values, etc.).

[0262] In some in situ bypass procedures, the saphenous vein is attached to an artery in the thigh and another artery in the calf, bypassing any blockages in the arteries. In some such procedures, the vein is not stripped from the patient, flipped lengthwise, and used as a prosthesis, but rather left in place so that blood flow is retrograde (to the valves of the vein). A standard valvulotomy can be placed into the saphenous vein from below and pushed to the top in a collapsed state, opened, and then pulled back in an open state, cutting the vein valve along the way. The cutting surface of such a valvulotomy faces backwards so that it cuts during retraction during these procedures. Fig.23A is a schematic perspective view of an example embodiment of a valvulotome 400 that may be used with such a procedure, including a proximally facing blade 402 .

[0263] In some embodiments of the methods described herein, access distal to the venous valve is unavailable, making it impossible to pull the valvulotome backward, but possible to push the reverse valvulotome forward as described herein. Fig. 23Bis a schematic perspective view of an example embodiment of a valvulotomy tool 410 that can be used with such a procedure. The reverse valvulotomy tool 410 includes one or more blades 412 (e.g., 2-5 blades (e.g., 3 blades)) facing forward or distally so that the valve can be cut when the reverse valvulotomy tool 410 is advanced distally. At least because retrograde access to the vein to be incapacitated was not previously considered a problem, there is no a priori motivation to reverse the direction of the blades of the valvulotomy tool to form the reverse valvulotomy tool 410 as described herein. The reverse valvulotomy tool 410 can be advanced over a guide wire 414, which can be manipulated into the vein for causing venous valve insufficiency. After a fistula is formed between an artery and a vein as described herein, the fluid flow in the vein is in a direction opposite to the natural or normal or pre-procedural direction of the fluid flow in the vein so as to push the reverse valvulotomy tool 410 in a direction opposite to the natural fluid flow but in the direction of the post-fistula fluid flow.

[0264] Other systems and methods can also be used to reconstruct valvular insufficiency in a vein (e.g., cutting balloons, atherectomy, laser ablation, ultrasonic ablation, heating, radiofrequency (RF) ablation, catheters with invasive or non-atraumatic tips that are advanced and / or retracted (e.g., introducer sheaths), combinations thereof, and the like).

[0265] It can also be challenging to traverse the venous valve in a retrograde manner prior to rendering such valvular regurgitation. Fig.24 420. It is a schematic perspective view of an example embodiment of a LeMaitre device 420, which can be used to radially expand veins and thus expand their valves. The LeMaitre device 420 includes expandable elliptical or elongated leaflets 422, such as a self-expanding nitinol mesh. In some embodiments, a PTA balloon catheter can be used to radially expand veins and thus radially expand their valves. In some embodiments, applying a tourniquet to a leg can radially expand veins and thus radially expand their valves. After radial expansion, a guide wire can be advanced through (one or more) stretched valves (e.g., by an expansion device such as the LeMaitre device) and a catheter (e.g., PTA, stent delivery, atherectomy, etc.) or other over-the-wire devices can be advanced on the guide wire.

[0266] Fig.26A and 26B Another example embodiment of a method for achieving retrograde perfusion is schematically illustrated. Referring again to Fig.20E, a fistula can be established between an artery 600 including an occlusion 604 and a vein 602 with a guidewire 606 extending therethrough using one or more of the techniques described herein and / or other techniques. A prosthesis delivery system carrying a prosthesis 620 is advanced over the guidewire 606 through the interstitial region between the artery 600 and the vein 602 and into the vein 602, as in Fig.26A In some embodiments, a separate PTA balloon catheter (e.g., approximately 2 mm) can be advanced over guidewire 606 to pre-enlarge the fistula between artery 600 and vein 602 prior to introduction of the prosthesis delivery system. The use of a PTA balloon catheter may depend, for example, on the radial strength of prosthesis 620. Prosthesis 620 may be Figures 25A-25C The stent 500, 520, 540 or its variations (e.g., as described with respect to Fig.25C ), the stent comprises uncovered and low porosity woven filaments configured to divert blood flow.

[0267] The flow diverting properties of the uncovered woven filaments may depend on certain hemodynamic properties of the vessel lumen. For example, if the occlusion 604 is not complete such that some pressure drop may occur between the lumen of the prosthesis 620 and the portion of the artery 600 between the occlusion 604 and the prosthesis 620, blood may be able to flow through the sidewalls of the prosthesis 620 rather than into the fistula. Referring again to Figure 4 As described with occluding material 251, occluding material 608 may optionally be provided in artery 600 to further occlude artery 600, which can prevent fluid dynamic effects that may cause and / or allow blood to flow through the side walls of prosthesis 620. For another example, a pressure drop between artery 600 and vein 602 may cause and / or allow blood to flow through the side walls of the prosthesis in the normal direction of venous blood flow rather than through the lumen of the prosthesis to achieve retrograde perfusion. Referring again to Figure 4 As described with occluding material 251, occluding material 610 may optionally be provided in vein 602 to occlude the portion of vein 602 downstream of the fistula under normal venous flow, which can prevent fluid dynamic effects that may cause and / or allow blood to flow through the side walls of prosthesis 620.

[0268] For example, by operating the trigger handle 194 ( Fig.17), deploying the prosthesis 620 from the prosthesis delivery system. In some embodiments, for example, if the prosthesis 620 cannot expand and / or advance, the prosthesis delivery system can be removed and the PTA catheter (e.g., approximately 2 mm) is advanced over the guidewire 620 to attempt to expand or further expand the fistula between the artery 600 and the vein 602. The deployment of the prosthesis 620 can then be retried (e.g., by self-expansion, balloon expansion, etc.). In some embodiments, the deployment of the prosthesis 620 can reshape the vessel, for example, expanding the diameter of the vessel as described herein. In embodiments where the prosthesis 620 is self-expanding, the degree of remodeling can change over time, for example, the prosthesis 620 expands when the vessel expands or the prosthesis 620 contracts when the vessel contracts. The prosthesis 620 can conform to the anatomical structure in which the prosthesis 620 is deployed. For example, in an expanded state on a surgical table or surface, the prosthesis 620 can be generally cylindrical, but the prosthesis 620 can conform to the diameter of the vessels and fistulas in which the prosthesis 620 is deployed such that the prosthesis can have different diameters in different longitudinal segments, tapers, non-cylindrical shapes, combinations thereof, and the like.

[0269] The prosthesis 620 includes a supplemental support structure (e.g., as described with respect to Fig.25B In some embodiments described herein, deployment of the prosthesis can include deploying a first woven structure and deploying a supplemental support structure before, during, and / or after deploying the first woven structure.

[0270] The fistula can optionally be enlarged using a PTA catheter before, during, and / or after deployment of the prosthesis 620. The diameter of the PTA catheter (e.g., about 3 mm to about 6 mm) can be selected based at least in part on the diameter of the artery 600, the diameter of the vein 602, the composition of the interstitial tissue, the properties of the prosthesis 620, combinations thereof, and the like.

[0271] Once the prosthesis 620 is in place, the prosthesis delivery system can be removed, such as in Fig.26B AV fistula is thereby formed between artery 600 and vein 602. Blood flows through the lumen of prosthesis 620 due to the hemodynamic effects of low porosity (e.g., less than about 50% porosity or other values ​​described herein) even though the prosthesis lacks or has no graft material. Fig.26B An embodiment is shown in which occlusive materials 608, 610 are not used.Once the prosthesis 620 is in place, the valve insufficiency in the vein can be rendered insufficient, for example, as described herein.

[0272] The prosthesis 620 includes two sets of multiple filaments that can be deployed separately (e.g., as described with respect to Fig.25BIn embodiments (as described in certain embodiments of the present invention), multiple filaments can be deployed at least partially simultaneously, deployed sequentially without an interventional step, or deployed sequentially with an interventional step (such as the PTA step described herein).

[0273] Fig. 27 Another example embodiment of a prosthesis 720 and a method for achieving retrograde perfusion is schematically illustrated. Although some sizes and even the example scale of "10 mm" are provided, the shapes, sizes, positional relationships, etc. of the features illustrated therein can be changed. The prosthesis 720 is positioned in the artery 700 including the occlusion 704, in the vein 702, and across the interstitial tissue T between the artery 700 and the vein 702. The prosthesis 720 can be positioned, for example, as described herein and / or using other methods. In some embodiments, the prosthesis 720 is delivered on a guidewire with an outer diameter of 2Fr (0.67 mm) by a delivery system with an inner diameter of 5Fr (1.67 mm).

[0274] In some embodiments, the porosity of the first longitudinal segment 722, the second longitudinal segment 724, and / or the third longitudinal segment 726, or one or more portions thereof, can be between about 0% and about 50% and range therebetween, e.g., as described herein. Blood flow from the artery 700 can be diverted into the vein 702 through the prosthesis 720, e.g., due to hemodynamic forces, such as a pressure difference between the artery 700 and the vein 702. The low porosity of the prosthesis 720 can allow fluid to flow substantially through the lumen of the prosthesis 720 without substantially perfusing through the sidewalls of the prosthesis 720. In some embodiments, the proximal and / or distal portions toward the end of the prosthesis 720 can be configured to adhere to the vessel sidewalls, e.g., have a lower porosity, because blood is unlikely to flow through those portions.

[0275] The techniques described herein may be useful for forming fistulas between two body cavities near the heart, in the periphery, or even in the lower extremities (plantar arches). Fig.28A and Fig.28B The artery and vein of the foot are schematically illustrated respectively. A fistula or anastomosis can be formed between two blood vessels of the foot. In one example, a passage from the artery to the vein is formed in the middle lateral plantar from the lateral plantar artery to the lateral plantar vein.

[0276] The artery supplying blood to the foot is occluded, and the subintimal space is calcified. The wire is pushed distally and crosses to the adjacent vein. The hole between the artery and the vein is enlarged using a 1.5mm balloon, for example because a small arteriovenous fistula should not cause any too large damage to the patient at or in this position. After the expansion, blood begins to flow from the artery to the vein without leakage. After such flow is confirmed, the further expansion of the space is performed using a larger balloon (2.0mm, 2.5mm, 3.0mm) with a greater pressure (e.g., 20-30atm). Even if there is no stent, graft, scaffolding, or other types of equipment placed, leakage is surprisingly minimal or non-existent. The procedure that does not include a prosthesis can reduce costs, procedural time, complexity, combinations thereof, and / or the like. The lateral plantar vein directly enters the venous arch of the forefoot, making it an outstanding candidate for supplying blood to this part of the foot. The patient had much pain in the foot before the procedure and no pain in the foot after the procedure, indicating that blood can be supplied retrogradely through the vein as described herein. The fistula or anastomosis maintenance device may optionally be omitted for certain situations, such as for hemodialysis situations where the distal or lower extremity arteries and veins may be described as "glued" in the surrounding tissue (e.g., the medial plantar lateral artery and vein).

[0277] In some cases, a fistula or anastomosis maintaining device may optionally be used.Several fistula maintaining devices are described herein. Fig.29 An example embodiment of an anastomotic device 800 is schematically illustrated. The anastomotic device includes a first segment 802, a second segment 804, and optionally a third segment 806 longitudinally between the first segment 802 and the second segment 804. The first segment 802 can be configured to be anchored in a first body cavity (e.g., a blood vessel, such as an artery or a vein). The first segment 802 may include an expandable member, a barb, etc. The second segment 804 can be configured to be anchored in a second body cavity (e.g., a blood vessel, such as an artery or a vein, which can be the opposite type of the first body cavity). The third segment 806 can be configured to span between the inner lumens of the first body cavity and the second body cavity. In some embodiments, the space between the inner lumens of the first body cavity and the second body cavity typically contains a vascular wall, so that the size of the third segment 806 can be very small or even omitted.

[0278] Some anastomotic devices are available and / or have been developed for treating holes in larger vessels (e.g., Spyder from Medtronic, CorLink from Johnson and Johnson, Symmetry from St. Jude Medical, PAS-Port from Cardica, and ROX Coupler from ROX Medical). Such devices may be suitable for use in the periphery or lower extremities, for example, if resized and / or reconfigured. Other devices are also possible.

[0279] Fig.30 Schematically illustrates an example embodiment of two blood vessels 902 and 904 coupled together using an anastomotic device 800 that spans the walls of the blood vessels 902 and 904. Blood vessel 902 is an artery, as schematically shown by having a thick wall, and blood vessel 904 is a vein. Other combinations of blood vessels and other body cavities are also possible. After a passage 906 is formed between a first blood vessel 902 and a second blood vessel 904, for example, as described herein (e.g., using a wire, a deployable needle, one or more balloons, etc.), the anastomotic device 800 is deployed. For example, the distal end of the anastomotic device 800 deployment system can reside in the first blood vessel 902 and partially extend through the passage 906. The first segment 802 of the anastomotic device 800 can be deployed through the passage 906 and in the second blood vessel 904. After deployment, the first segment 802 can self-expand, for example, to adhere to the wall of the second blood vessel 904. The third segment 806 of the anastomotic device 800 can be deployed through the passage 906. After deployment, the third segment 806 can self-expand, for example, to adhere to tissue around the passage 906 and maintain patency through the passage 906. The second segment 804 of the anastomotic device 800 can be deployed in the first blood vessel 902. After deployment, the second segment 804 can self-expand, for example, to adhere to the wall of the first blood vessel 902. One or more of the first segment 802, the second segment 804, and the third segment 806 can be expanded using a balloon. Different balloons or a series of balloons can be used for different segments 802, 804, 806 of the anastomotic device 800.

[0280] Although some exemplary embodiments have been disclosed in detail herein, this has been done by way of example and for illustrative purposes only. The above-described embodiments are not intended to be limiting with respect to the scope of the appended claims. The inventors contemplate that various substitutions, changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention as defined in the claims.

[0281] While the devices described herein may be used in applications where the fluid flowing through the device is a liquid such as blood, the devices may also or alternatively be used in applications such as tracheal or bronchial surgeries where the fluid is a gas such as air. In some embodiments, the fluid may contain solid matter, such as emboli or, in gastric surgery where the fluid includes food particles.

[0282] Although the present invention is susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and described in detail herein. However, it should be understood that the present invention is not limited to the specific forms or methods disclosed, but, on the contrary, the present invention covers all modifications, equivalents and alternatives falling within the spirit and scope of the various embodiments described and the appended claims. Any method disclosed herein does not have to be performed in the order described. The methods disclosed herein include certain actions taken by the practitioner; however, they may also include any third-party instructions for these actions, whether explicit or implicit. For example, actions such as "causing valvular insufficiency in the first vessel" include "instructions to cause valvular insufficiency in the first vessel". The ranges disclosed herein also include any and all overlaps, sub-ranges and combinations thereof. Language such as "up to", "at least", "greater than", "less than", "between", etc. include the numbers described. Numbers prefixed with terms such as "about" or "approximately" include the numbers described. For example, "about 10 mm" includes "10 mm". Terms or phrases prefixed with terms such as "substantially / generally" include the terms or phrases described. For example, "substantially parallel / generally parallel" includes "parallel".

Claims

1. A system for targeting a second channel from a first channel to achieve retrograde perfusion in the second channel, the system comprising: a first catheter configured to be inserted into a first vessel to form a fistula between the first vessel and a second vessel, the first vessel comprising an artery, the first catheter comprising a needle; a second catheter configured to be inserted into the second vessel, the second vessel comprising a vein, the second catheter comprising a non-occlusive expandable mesh, the expandable mesh comprising a radiopaque material; a guidewire configured to be advanced from the first vessel, through the needle and into the second vessel; a prosthesis configured to be tracked over the guidewire and expanded by a balloon such that the prosthesis is at least partially deployed within the fistula, wherein after deployment of the prosthesis, blood is diverted from the first vessel to the second vessel through the prosthesis; as well as a stent graft configured to be positioned in the second vessel such that the stent graft is configured to cover a collateral vessel of the second vessel and to relieve valvular regurgitation in the second vessel, the stent graft being separate from the prosthesis, wherein the needle is configured to extend radially outward from the first catheter, away from the first vessel, through interstitial tissue between the first vessel and the second vessel, into the second vessel, and penetrate the expandable mesh to confirm advancement of the needle into the second vessel, and Wherein the needle is configured to be aligned with the expandable mesh by rotating the first catheter within the first channel. 2 . The system of claim 1 , wherein the proximal segment of the stent-graft is configured to be positioned radially outward of the distal segment of the prosthesis.

3. The system of claim 1 further comprising a cutting balloon or a valvulome.

4. The system of claim 1, wherein the expandable mesh is configured to self-expand.

5. The system of any one of claims 1 to 4, wherein a proximal segment of the stent-graft is configured to longitudinally overlap a distal segment of the prosthesis.

6. The system of claim 1, wherein the expandable mesh is configured to close to grasp a distal portion of the guidewire.

7. The system of claim 1, wherein the expandable mesh is configured to close around the guidewire to grasp the guidewire in the second channel.

8. The system of claim 1, wherein the expandable mesh comprises one or more ring structures.

9. The system of claim 8, wherein the one or more ring structures are configured to expand radially outward from a distal segment of the prosthesis.

10. A system for targeting a second channel from a first channel to achieve retrograde perfusion in the second channel, the system comprising: a first catheter configured to be inserted into the first channel, the first catheter comprising a needle, the first channel comprising an artery, and the second channel comprising a vein; a second catheter configured to be inserted into the second passageway, the second catheter comprising a non-occlusive expandable mesh, wherein the expandable mesh comprises a radiopaque material; Prostheses; and Venous stents, wherein the needle is configured to be advanced radially outward from the first catheter in the first channel and into the second channel to form a fistula between the first channel and the second channel and to penetrate the expandable mesh in the second channel, wherein the prosthesis is configured to be deployed between the first passage and the second passage such that, after deployment of the prosthesis, a first portion of the prosthesis is located in the first passage, a second portion of the prosthesis is located in the second passage, and a third portion of the prosthesis is located in the fistula, wherein the venous stent comprises a proximal segment configured to overlap with the second portion of the prosthesis, wherein the venous stent is configured to fill the sidewall of the second channel, and Wherein the needle is configured to be aligned with the expandable mesh by rotating the first catheter within the first channel.

11. A system for targeting a second channel from a first channel to achieve retrograde perfusion in the second channel, the system comprising: a first catheter configured to be inserted into the first passage, the first catheter comprising a needle; a second catheter configured to be inserted into the second passageway, the second catheter comprising a non-occlusive expandable mesh, wherein the expandable mesh comprises a radiopaque material; Prostheses; and Venous stents, wherein the needle is configured to be advanced radially outward from the first catheter in the first channel and into the second channel to form a fistula between the first channel and the second channel and to penetrate the expandable mesh in the second channel, wherein the prosthesis is configured to be deployed between the first passage and the second passage such that, after deployment of the prosthesis, a first portion of the prosthesis is located in the first passage, a second portion of the prosthesis is located in the second passage, and a third portion of the prosthesis is located in the fistula, wherein the venous stent is separated from the third portion of the prosthesis, wherein the venous stent is configured to fill the sidewall of the second channel, and Wherein the needle is configured to be aligned with the expandable mesh by rotating the first catheter within the first channel.

12. A system for targeting a second channel from a first channel to achieve retrograde perfusion in the second channel, the system comprising: a first catheter configured to be inserted into the first passage, the first catheter comprising a needle; a second catheter configured to be inserted into the second passageway, the second catheter comprising a non-occlusive expandable mesh, wherein the expandable mesh comprises a radiopaque material; Prostheses; and Venous stents, wherein the needle is configured to be advanced radially outward from the first catheter in the first channel and into the second channel to form a fistula between the first channel and the second channel and to penetrate the expandable mesh in the second channel, wherein the prosthesis is configured to be deployed between the first passage and the second passage such that a first portion of the prosthesis is in the first passage, a second portion of the prosthesis is in the second passage, and a third portion of the prosthesis is in the fistula, wherein the venous stent is separated from the third portion of the prosthesis, and Wherein the needle is configured to be aligned with the expandable mesh by rotating the first catheter within the first channel.

13. The system of any one of claims 10 to 12, wherein the prosthesis comprises a stent graft configured to be expanded by a balloon.

14. The system of any one of claims 10 to 12, further comprising a cutting balloon or a valvulotome.

15. The system of any one of claims 10 to 12, further comprising a cutting balloon, wherein the first channel comprises an artery, wherein the second channel comprises a vein, wherein the prosthesis is configured to be expanded by a balloon, and wherein the needle is configured to be advanced through interstitial tissue after pushing the needle out of the first channel and before advancing the needle into the second channel.

16. The system of any one of claims 10 to 12, wherein the expandable mesh is configured to self-expand.

17. The system of any one of claims 10 to 12, further comprising a guidewire configured to be advanced from the first channel, through the needle, and into the second channel, wherein the expandable mesh is configured to close around the guidewire to hold the guidewire in the second channel.

18. The system of claim 17, wherein the expandable mesh is configured to close to grasp a distal portion of the guidewire.

19. The system of any one of claims 10 to 12, wherein the expandable mesh comprises one or more ring structures.

20. The system of claim 19, wherein the one or more ring structures are configured to expand radially outward from a distal segment of the prosthesis.

Images