Catheter alignment apparatus and method

Abstract

To provide a method and a system for improving a transdermal method and a transdermal system.SOLUTION: A launching catheter for targeting a second vessel from a first vessel includes a catheter 4206 including a proximal portion and a distal portion 4204 including a needle opening and a flat, rectangular radiopaque marker 4210. The flat rectangular radiopaque marker disappears under fluoroscopy upon rotation and provides information about the rotational alignment of the launching catheter. The launching catheter includes a needle configured to extend through the needle opening. A method of registering the catheter includes rotating the catheter within the first blood vessel until the marker has a thickness (e.g., a minimum thickness) under fluoroscopy. The thickness 4234 indicates the rotational alignment of the catheter.SELECTED DRAWING: Figure 42B

Description

[Technical Field]

[0001] This application relates to methods and systems for use in percutaneous interventional surgery. In particular, this application relates to methods and systems for providing or maintaining fluid flow through bodily passageways such as heart chambers and blood vessels.

[0002] [Incorporated by reference] This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 743,107, filed October 9, 2018, U.S. Provisional Patent Application No. 62 / 817,217, filed March 12, 2019, and U.S. Provisional Patent Application No. 62 / 887,274, filed August 15, 2019, each of which is incorporated herein by reference in its entirety. [Background technology]

[0003] Minimally invasive percutaneous surgery, or "keyhole" surgery, is a surgical procedure in which surgical devices are inserted into a patient's body cavities through small incisions made in the skin. This form of surgery is becoming increasingly popular because it allows patients to endure less surgical discomfort while retaining the benefits of traditional surgery. Patients treated with such procedures experience less discomfort, the need for general anesthesia, less trauma, and less risk of infection, and recovery times can be significantly reduced compared to traditional surgical procedures.

[0004] Keyhole surgery can be used, for example, in laparoscopic surgery, to treat cardiovascular disease. When treating cardiovascular disease, balloon angioplasty, in which a balloon catheter is inserted into an artery, usually near the patient's groin, and guided to the patient's heart, where a balloon at the distal portion of the catheter is inflated to open or widen the blocked vessel and help restore blood flow to the heart tissue, can be used to treat partially blocked coronary arteries as an alternative to open-heart surgery. A tubular support device (e.g., a stent) can be deployed at the site of the blockage to prevent subsequent closure (restenosis) or collapse of the vessel. The stent can be, for example, an expandable metal mesh tube carried by the balloon of a balloon catheter, or it can be self-expanding. A balloon-expandable stent expands when the balloon is inflated, thereby pressing the stent against the wall of the vessel. Once the stent reaches its expanded position, it is configured to retain its expanded shape, for example, by plastic deformation or a mechanical locking mechanism, to form a resilient scaffold or support within the vessel. Support structures (e.g., stents) support the walls of blood vessels and expand them to maintain a path for blood flow through the vessel. Self-expanding stents are also available, which are held in a collapsed state by a suitably adapted catheter for delivery through the artery and assume an expanded state upon deployment at the site of the blockage. The catheter, for example, can have a retention sleeve that holds the stent in a compressed or unexpanded state. When the sleeve is removed from the stent, the stent expands to support and expand the walls of the vessel.

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

[0006] Conventional coronary artery bypass surgery is not always optional. Some patients are poor candidates for conventional coronary artery bypass surgery due to poor chances of recovery or high risk of significant trauma from the surgery, high risk of infection, lack of healthy blood vessels to use as a bypass graft, significant comorbidities, and the expected long and tedious recovery time associated with open-heart surgery. For example, factors such as diabetes, old age, obesity, and smoking may exclude some candidate patients who truly need such treatment. Summary of the Invention

[0007] The present application provides methods and systems that overcome certain deficiencies and / or improve percutaneous methods and systems. For example, according to certain embodiments, the methods and systems described herein may improve the targeting and localization of therapy administration and may advantageously allow percutaneous procedures to be performed on patients who are ineligible for more invasive procedures. Some embodiments described herein may provide fluid flow within passageways, such as coronary and / or peripheral vessels, by creating a bypass using minimally invasive percutaneous surgical techniques.

[0008] In some examples, a launch catheter for targeting a first blood vessel to a second blood vessel includes a catheter including a proximal portion and a distal portion including a flat radiopaque marker. The radiopaque marker can be rectangular. The catheter can include a needle opening. The catheter can include a needle configured to extend through the needle opening.

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

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

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

[0012] The ratio of the length of the marker to the width of the marker may be between 1 / 1 and 5 / 1.

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

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

[0015] In some examples, a launch catheter for targeting a first blood vessel to a second blood vessel includes a catheter including a proximal portion and a distal portion including a needle opening and a flat, rectangular radiopaque marker that disappears under fluoroscopy upon rotation to provide information regarding the rotational alignment of the launch catheter. The launch catheter further includes a needle configured to extend through the needle opening.

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

[0017] In some examples, a method of aligning a catheter includes rotating a catheter within a first blood vessel. The catheter includes a flat radiopaque marker. The rotation is performed until the marker reaches a thickness that indicates rotational alignment of the catheter. The thickness is visible under fluoroscopy. The thickness can be less than a certain value. The thickness can be indicated by a thin (e.g., minimally thick) line. The radiopaque marker can be rectangular.

[0018] The method can include rotating the catheter within the first blood vessel until the marker has a thickness (e.g., a minimal thickness) under fluoroscopy and abuts a side of the catheter. The method can further include longitudinally advancing the catheter until the marker is proximate to a second catheter within the second blood vessel. The second catheter can include a radiopaque feature visible under fluoroscopy. The radiopaque feature of the second catheter visible under fluoroscopy can include an expandable member. The expandable member can include a snare. The expandable member can include a mesh.

[0019] The method can further include extending the needle from the catheter after rotating the catheter. Extending the needle from the catheter can include exiting the first blood vessel and entering a second blood vessel different from the first blood vessel. Aligning the catheter can include aligning the needle. Extending the needle from the catheter can include traversing interstitial tissue between the first blood vessel and the second blood vessel.

[0020] The method can further include extending a guidewire through the needle and into the second blood vessel. The method can further include entangling the guidewire to a second catheter in the second blood vessel. Entangling the guidewire can include occluding an expandable member of the second catheter. The method can further include moving the second catheter to detect corresponding movement of the guidewire. The method can further include moving the second catheter to move the guidewire through the second blood vessel.

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

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

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

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

[0025] The expandable member can be coupled to the tubular body. The catheter system can further include a second tubular body. The expandable member can be coupled to the second tubular body. The expandable member can be configured to appose sidewalls of the blood vessel to occlude the blood vessel. The catheter system can further include a fluid injection port. The tubular body can include a fluid injection port. The catheter system can further include a second tubular body including a fluid injection port. The targeting system can include an ultrasound transducer. The targeting system can include an omnidirectional ultrasound transducer.

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

[0027] The tubular body may include a fluid injection port. The catheter system may further include a second tubular body including a fluid injection port. The catheter system may further include an expandable member. The expandable member may be coupled to the tubular body. The catheter system may further include a second tubular body. The expandable member may be coupled to the second tubular body. The expandable member may be configured to appose sidewalls of the blood vessel to occlude the blood vessel. The targeting system may include an ultrasound transducer. The targeting system may include an omnidirectional ultrasound transducer.

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

[0029] The tubular body may include a fluid injection port. The catheter system may further include a second tubular body including a fluid injection port. The expandable member may be coupled to the tubular body. The catheter system may further include a second tubular body. The expandable member may be coupled to the second tubular body. The expandable member may be configured to appose sidewalls of the blood vessel to occlude the blood vessel. The catheter system may further include a targeting system. The targeting system may include an ultrasound transducer. The targeting system may include an omnidirectional ultrasound transducer. A method of identifying a bifurcation may include inserting the catheter system into a first blood vessel, positioning the catheter system at a first position, expanding the expandable member to occlude the first blood vessel, and delivering a contrast agent to the first blood vessel. The contrast agent may pool near the expandable member. The method may further include reviewing the shape of the contrast agent within the first blood vessel under fluoroscopy.

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

[0031] The single catheter may include an expandable member and a fluid injection port. The first catheter may include an expandable member, and the second catheter may include a fluid injection port. Expanding the expandable member may include providing a fluid flow through the inflation lumen in fluid communication with the expandable member. Expanding the expandable member may include dilating the first blood vessel. The contrast agent may include at least one of an iodine-based contrast agent and a barium sulfate-based contrast agent. Delivering the contrast agent may include dilating the first blood vessel. Reviewing the shape of the contrast agent may include identifying the presence of at least one of a bifurcation and a branched blood vessel. The method may further include repositioning the catheter system if at least one of a bifurcation and a branched blood vessel is present. The method may further include extending a needle from another catheter in the second blood vessel if at least one of a bifurcation and a branched blood vessel is not present. Extending the needle can include exiting the second blood vessel, traversing interstitial tissue between the second blood vessel and the first blood vessel, and entering the first blood vessel. The method can further include advancing a guidewire through the needle. The catheter system can include a capture element configured to guide the guidewire into the guidewire lumen.

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

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

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

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

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

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

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

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

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

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

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

[0043] Advancing the bidirectional valvulotome proximate the valve can include advancing the bidirectional valvulotome in a direction against natural fluid flow. Advancing the bidirectional valvulotome proximate the valve can include advancing the bidirectional valvulotome in the direction of natural fluid flow. Advancing the bidirectional valvulotome proximate the valve can include advancing the bidirectional valvulotome proximal to the valve. Advancing the bidirectional valvulotome proximate the valve can include advancing the bidirectional valvulotome distal to the valve.

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

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

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

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

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

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

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

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

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

[0053] The porosity can be between about 0% and about 50%. The porosity can be between about 5% and about 50%. The prosthesis can be substantially free of graft material. The prosthesis can have a first longitudinal segment having the above-mentioned porosity and a second longitudinal segment having a second porosity different from the above-mentioned porosity. The second longitudinal segment can have parameters different from the first longitudinal segment. The parameters can include at least one of braid angle, filament diameter, filament material, weave diameter, weave shape, and secondary support structure. The prosthesis can further have a third longitudinal segment between the first longitudinal segment and the second longitudinal segment. The third longitudinal segment can have parameters different from at least one of the first longitudinal segment and the second longitudinal segment. The parameters can include at least one of braid angle, filament diameter, filament material, weave diameter, weave shape, and secondary support structure. The prosthesis can further include a secondary support structure. The secondary support structure can include a second plurality of filaments woven together into a second weave, the second plurality of filaments having different parameters than the first plurality of filaments. The parameters can include at least one of a braid angle, a filament diameter, a weave diameter, and a filament material. The secondary support structure can include a cut hypotube. The plurality of filaments can include filaments including a shape memory material (e.g., Nitinol) and a prosthesis including a biocompatible polymer (e.g., Dacron®, Kevlar®).

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

[0055] The porosity can be between about 0% and about 50%. The porosity can be between about 5% and about 50%. The prosthesis can be substantially free of graft material. The second longitudinal segment can have parameters different from the first longitudinal segment. The parameters can include at least one of braid angle, filament diameter, filament material, diameter, shape, and auxiliary support structure. The third longitudinal segment can have a second porosity different from the porosity. The first longitudinal segment can be balloon-expandable. The second longitudinal segment can be self-expanding. The prosthesis can include a plurality of filaments woven together into a woven structure. The plurality of filaments can include filaments including a shape-memory material (e.g., Nitinol) and a prosthesis including a biocompatible polymer (e.g., Dacron®, Kevlar®). The third longitudinal section can have parameters different from at least one of the first longitudinal section and the second longitudinal section. The parameters can include at least one of braid angle, filament diameter, filament material, diameter, shape, and ancillary support structures. The prosthesis can further include an ancillary support structure. The first longitudinal section can be substantially cylindrical and can have a first diameter, the second longitudinal section can be substantially cylindrical and can have a second diameter larger than the first diameter, and the third longitudinal section can be frustoconical and tapered from the first diameter to the second diameter. The first longitudinal section can be substantially cylindrical and can have a first diameter, and the second longitudinal section and the third longitudinal section can be frustoconical and tapered from the first diameter to a second diameter larger than the first diameter.

[0056] In some embodiments, an implantable prosthesis for treating an occlusion in a first blood vessel comprises a plurality of filaments woven 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, and a porosity of about 5% to about 50%.

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

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

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

[0060] The first blood vessel can be an artery. The duct can be a vein. The method can include enlarging the fistula. The first blood vessel can be substantially parallel to the second blood vessel. Deploying the prosthesis can include self-expanding the prosthesis. Deploying the prosthesis can include balloon-expanding the prosthesis. Deploying the prosthesis can include deploying a woven structure and deploying a secondary support structure. Deploying the secondary support structure can occur before deploying the woven structure. Deploying the secondary support structure can occur after deploying the woven structure. The secondary support structure can include a second plurality of filaments woven into a second woven structure. The secondary support structure can include a cut hypotube. The method can further include forming a fistula. Forming the fistula can include inserting a launch catheter into the first blood vessel and inserting a target catheter into the second blood vessel. The launch catheter can include an ultrasound transmitting transducer and a needle configured to extend radially from the launch catheter. The target catheter can include an ultrasound receiving transducer. Forming the fistula can include transmitting an ultrasound signal from the ultrasound transmitting transducer, at least one of rotating the launch catheter and longitudinally moving the launch catheter while transmitting the ultrasound signal until the ultrasound signal can be received by the ultrasound receiving transducer, and extending a needle from the launch catheter after receiving the ultrasound signal by the ultrasound receiving transducer, the extending the needle including exiting the first blood vessel, crossing interstitial tissue between the first blood vessel and the second blood vessel, and entering the second blood vessel. The method can further include disabling a valve in the second blood vessel. Disabling the valve in the second blood vessel can include ablating the valve using a retrograde valvulotome. Disabling the valve in the second blood vessel can include inflating a balloon.Disabling the valve in the second vessel can include expanding a stent. Disabling the valve in the second vessel can include lining the second vessel with a stent. The stent can comprise a covering or a graft. Lining the second vessel can include covering collateral vessels of the second vessel. The stent can be separate from the prosthesis. The stent can be spaced apart from the prosthesis along the length of the second vessel. Ends of the stent can abut ends of the prosthesis. A portion of the stent can longitudinally overlap a portion of the prosthesis. The portion of the stent can be radially inward of the portion of the prosthesis. The method can include expanding the stent after deploying the prosthesis. The portion of the prosthesis can be radially inward of the portion of the stent. The method can include expanding the stent before deploying the prosthesis. The stent can be integral with the prosthesis.

[0061] In some embodiments, an implantable prosthesis for maintaining patency of an anastomosis between an artery and a vein in a lower limb includes a first section configured to reside in an artery of the lower limb, a second section configured to reside in a vein of the lower limb, and a third section longitudinally disposed between the first and second sections, the third section configured to maintain patency of the anastomosis between the artery and the vein.

[0062] The first section can be configured to appose the wall of a lower limb artery. The first section can have barbs. The second section can be configured to appose the wall of a lower limb vein. The second section can have barbs. At least one of the first section, second section, and third section can be self-expanding. At least one of the first section, second section, and third section can be balloon-expandable. The length of the second section can be greater than the length of the first section. The second section can be configured to disable a valve in a lower limb vein. The second section can be configured to cover a collateral vessel of the lower limb vein.

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

[0064] Forming the hole can include pushing a wire from the first vessel into the second vessel. Forming the hole can include traversing a needle from the first vessel into the second vessel. Dilating the hole can include enlarging the hole using at least one balloon. Enlarging the hole can include using multiple balloons with progressively larger diameters. A first balloon of the multiple balloons can have a diameter of about 1.5 mm, and a final balloon of the multiple balloons can have a diameter of about 3 mm. The multiple balloons can include a first balloon having a diameter of about 1.5 mm, a second balloon having a diameter of about 2.0 mm, a third balloon having a diameter of about 2.5 mm, and a third balloon having a diameter of about 3.0 mm. Enlarging the hole with multiple balloons can include using progressively higher balloon inflation pressures. The method may not include (e.g., lack or eliminate) deploying a prosthesis (e.g., without using a stent, graft, scaffold, or other prosthesis). The positions of the first and second vessels can be substantially maintained by anatomical structures surrounding the first and second vessels. The method can further include positioning a prosthesis at the anastomosis. Positioning the prosthesis at the anastomosis can include placing the prosthesis within at least one of the first and second vessels. The first vessel can include the lateral plantar artery. The second vessel can include the lateral plantar vein.

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

[0066] The catheter may further include a guidewire sheath extending through the sheath and the expandable element. The proximal end of the expandable element may be coupled to the guidewire sheath. The expandable element may be configured to dilate a blood vessel upon deployment. The expandable element may be visible under fluoroscopy. The expandable element may include struts defining a plurality of cells. The struts may be deflectable upon contact with a needle. The catheter may further include an ultrasound receiving transducer. The ultrasound receiving transducer may be distal to the expandable element. The ultrasound receiving transducer may be longitudinally between the proximal end of the expandable element and the distal end of the expandable element. The ultrasound receiving transducer may be proximal to the expandable element. A method for capturing a guidewire can include inserting a catheter into a first blood vessel, expanding an expandable element to an expanded state in the first blood vessel, and extending a needle from a second blood vessel through interstitial tissue into the first blood vessel between a proximal end of the expandable element and a distal end of the expandable element. Extending the needle can include extending through one of the cells. The method can further include extending a guidewire through the needle and into the expandable element and collapsing the expandable element to a collapsed state. Collapsing the expandable element can include snare-ing the guidewire.

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

[0068] Collapsing the expandable element can include twisting the expandable element. Expanding the expandable element can include dilating the first blood vessel. Extending the needle can include targeting the expandable element under fluoroscopy. The method can further include proximally retracting the expandable element. Proximally retracting the expandable element can include routing a guidewire through the first blood vessel.

[0069] In some embodiments, a device for deploying a tubular structure includes, or consists essentially of, a handle body, a knob, and a slider. The handle body includes a first segment including a thread, a second segment longitudinally adjacent and proximal to the first segment, and a longitudinal slot. The second segment is unthreaded. The knob includes a thread. The knob is at a distal end of the first segment in a start position. The slider is operably connected to the knob. The slider is coupled to a sheath. The knob is configured to rotate proximally around the handle body of the first segment and to slide proximally along the handle body of the second segment. The slider is configured to retract the sheath proximally a first amount while rotating the knob, and to retract the sheath proximally a second amount while sliding the knob. The device is configured to fully deploy the tubular structure after the sheath is retracted the second amount.

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

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

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

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

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

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

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

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

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

[0079] In some embodiments, a method of accessing a lateral plantar vein of a subject comprises, or consists essentially of, placing a first tourniquet above the ankle of the leg, placing a needle in a dorsal medial plantar vein of the foot toward the toes of the leg, advancing a first guidewire into a first metatarsal vein of the foot, injecting a volume of contrast agent, and performing a venogram to image the plantar veins of the leg using fluoroscopy.

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

[0081] In some embodiments, a method of performing an ascending venography procedure comprises or consists essentially of injecting a volume of contrast agent into the venous vasculature through a first metatarsal vein.

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

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

[0084] The method may further include extending a guidewire through the needle into the second blood vessel and entangling the guidewire to a second catheter in the second blood vessel. Entangling the guidewire may include occluding an expandable member of the second catheter. The method may further include, after extending the guidewire, moving the second catheter and detecting corresponding movement of the guidewire to confirm entanglement of the guidewire in the second catheter. The method may further include moving the second catheter to move the guidewire through the second blood vessel. Moving the second catheter to move the guidewire through the second blood vessel may include exiting the second blood vessel at a location in the leg.

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

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

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

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

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

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

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

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

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

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

[0095] The system may further include an outer sheath. The snare structure and the valvulotome structure may be interchangeable in the outer sheath. The valvulotome structure may be proximal to the snare structure. The snare structure may be configured to extend from a distal end of the outer sheath. The valvulotome structure may be monolithic with the snare structure. The outer sheath may include a plurality of openings. The valvulotome structure may be configured to extend laterally from the outer sheath through the plurality of openings. The snare structure may include a plurality of cells configured to receive a guidewire. The snare structure may include a plurality of struts configured to snare the guidewire. The snare structure may include a plurality of wires configured to snare the guidewire. The valvulotome structure may be proximal to the snare structure. The valvulotome structure may be distal to the snare structure. The valvulotome structure may be monolithic with the snare structure. The snare structure can have a first diameter and the valvulotome structure can have a second diameter smaller than the first diameter. The snare structure can be configured to flip into the valvulotome structure upon application of a longitudinal force to the snare structure. The valvulotome structure can be separated from the snare structure. The valvulotome structure can be configured to snap into the snare structure. The snare structure can be configured to snap into the valvulotome structure. The valvulotome structure can include an expandable member configured to apply a radially outward force to the snare structure. The valvulotome structure can include a plurality of blades. The plurality of blades can include between two blades and eight blades. The plurality of blades can include three blades. The plurality of blades can include four blades. The plurality of blades can face proximally. The plurality of blades can face distally. The plurality of blades can face proximally and distally.

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

[0097] In some embodiments, a method of accessing a plantar vein of a subject includes placing the subject in a reverse Trendelenburg position, placing a first tourniquet on the leg above the knee, placing a second tourniquet on the leg above the ankle, injecting a quantity of contrast agent through a metatarsal vein, laying the subject flat after injecting the quantity of contrast agent through the metatarsal vein, creating a venogram to image the foot veins of the leg using fluoroscopy, selecting a plantar vein using the venogram, advancing a guidewire into the selected plantar vein, removing the second tourniquet, tracking a functional catheter over the guidewire, snare a second guidewire extending from the artery using the functional catheter, retracting the second guidewire from the foot, and tracking the second functional catheter over the second guidewire.

[0098] The metatarsal vein can be a dorsal metatarsal vein. The metatarsal vein can be a plantar metatarsal vein. The functional catheter can include a catheter for forming a fistula (e.g., a targeting catheter, a firing catheter). The second functional catheter can include a valve override device. The valve override device can include a valvulotome. The valve override device can include a cutting balloon. The valve override device can include an atherectomy device.

[0099] In some embodiments, a method of accessing a plantar vein of a subject includes injecting a volume of contrast agent through a metatarsal vein, creating a venogram to image the foot veins of the leg using fluoroscopy, selecting a plantar vein using the venogram, advancing a guidewire into the selected plantar vein, tracking a functional catheter over the guidewire, extending a second guidewire from the artery into the plantar vein, snare the second guidewire with the functional catheter, retracting the second guidewire from the foot, and tracking the second functional catheter over the second guidewire.

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

[0101] In some embodiments, a method of accessing a plantar vein of a subject includes injecting a volume of contrast agent through a metatarsal vein, creating a venogram to image the foot veins of the leg using fluoroscopy, selecting a plantar vein using the venogram, advancing a guidewire into the selected plantar vein, and tracking a functional catheter over the guidewire.

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

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

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

[0105] In some embodiments, a method of accessing a subject's tibial vein includes placing a first tourniquet above the knee of a leg, placing a second tourniquet above the ankle of the leg, injecting a volume of contrast agent through a metatarsal vein, performing a venogram to image the pedicle veins of the leg using fluoroscopy, selecting a tibial vein using the venogram, advancing a guidewire into the selected tibial vein, removing the second tourniquet, and tracking a functional catheter over the guidewire. The first tourniquet can be a different type than the second tourniquet.

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

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

[0108] In some embodiments, a method of positioning a catheter includes placing a catheter including a radiopaque marker in a blood vessel and rotating the catheter until a thickness of the radiopaque marker is minimized. Rotating the catheter can include producing a signal that the thickness is minimized.

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

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

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

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

[0113] In some embodiments, a method of positioning a catheter includes placing a first catheter in a first blood vessel and placing a catheter in a second blood vessel, the catheter including a radiopaque marker, the method further including rotating the catheter until a thickness of the radiopaque marker is minimized and generating a signal that the thickness is minimized.

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

[0115] It will be understood that the methods outlined above and described in more detail below describe some actions taken by a general practitioner, but may also include prescribing those actions to be taken by others. Thus, a measure such as "disabling a valve in a first blood vessel" includes "prescribing disabling a valve in a first blood vessel."

[0116] For purposes of outlining the invention and the advantages that may be achieved, certain objects and advantages are described herein. Not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment. In some embodiments, the invention may be embodied or performed in a manner that may achieve or optimize one advantage or group of advantages without necessarily achieving other objects or advantages.

[0117] All of these embodiments are intended to be within the scope of the invention(s) disclosed herein. These and other embodiments will become apparent from the following detailed description, which refers to the accompanying drawings, without limiting the invention to any particular disclosed embodiment(s). Any features and / or preferred features described with reference to some embodiments may be combined with and incorporated into other embodiments. All documents mentioned herein, including patents and patent applications, are incorporated by reference in their entirety.

[0118] These and other features, aspects and advantages of the present disclosure will be described with reference to drawings of several embodiments, which are intended to illustrate several embodiments but not to limit the invention, and in which like reference numerals are used for like features. [Brief explanation of the drawings]

[0119] [Figure 1] 1A-1C are schematic diagrams illustrating an exemplary embodiment of a launch device for directing a signal from a first body cavity to a target device in a second body cavity. [Figure 2] FIG. 2 is a cross-sectional view taken along the dotted line BB in FIG. [Figure 3] 1A and 1B are schematic diagrams illustrating an exemplary embodiment of a launcher; [Figure 4] 1A and 1B are schematic diagrams illustrating an exemplary embodiment of a launcher; [Figure 5]FIG. 10 is a schematic diagram of another exemplary embodiment of a launcher. [Figure 6] 1A and 1B are schematic diagrams illustrating exemplary embodiments of a centering device for a launcher and / or targeting device. [Figure 7] 1A and 1B are schematic diagrams showing a prosthesis in place following a procedure such as arterial-venous arterialization. [Figure 8] 1 is a side perspective view of an exemplary embodiment of an apparatus for providing a fluid flow; [Figure 9] FIG. 9 shows the device of FIG. 8 used as a shunt between two blood vessels. [Figure 10] FIG. 10 is a side perspective view of another exemplary embodiment of an apparatus for providing a fluid flow. [Figure 11] FIG. 10 is a side perspective view of yet another exemplary embodiment of an apparatus for providing a fluid flow. [Figure 12] FIG. 10 is a side perspective view of yet another exemplary embodiment of an apparatus for providing a fluid flow. [Figure 13] 10 is a side perspective view of yet another exemplary embodiment of an apparatus for providing a fluid flow. FIG. [Figure 14A] 1 is a schematic side cross-sectional view of an exemplary embodiment of an ultrasound emitting catheter. [Figure 14B] 14B is an enlarged schematic side cross-sectional view of a distal portion of the ultrasound emitting catheter of FIG. 14A within circle 14B. [Figure 15A] 1 is a schematic side elevational view of an exemplary embodiment of an ultrasound targeting catheter. [Figure 15B] 15B is an enlarged schematic side cross-sectional view of the ultrasound targeted catheter of FIG. 15A within circle 15B. [Figure 15C] 15C is an enlarged schematic side cross-sectional view of the ultrasound targeted catheter of FIG. 15A within circle 15C. [Figure 16] 10A-10C illustrate an exemplary embodiment of a graph for detecting catheter alignment. [Figure 17] 1 is a schematic side elevation view of an exemplary embodiment of a prosthesis delivery system. [Figure 18]1 is a schematic side elevational view of an exemplary embodiment of a prosthesis. [Figure 19] FIG. 10 is a schematic side elevational view of another exemplary embodiment of a prosthesis. [Figure 20A] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20B] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20C] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20D] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20E] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20F] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20G] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 20H] 1A-1C are diagrams illustrating an exemplary embodiment of a method for performing retrograde perfusion. [Figure 21] 1 is a schematic perspective view of an exemplary embodiment of an ultrasonic receiving transducer. [Figure 22] 1 is a schematic cross-sectional view of another exemplary embodiment of an ultrasonic receiving transducer. [Figure 23A] 1 is a schematic perspective view of an exemplary embodiment of a valvulotome. [Figure 23B] 1 is a schematic perspective view of an exemplary embodiment of a retrograde valvulotome. [Figure 24] 1 is a schematic perspective view of an exemplary embodiment of a LeMaitre device; [Figure 25A] FIG. 10 is a schematic side elevational view of yet another exemplary embodiment of a prosthesis. [Figure 25B] FIG. 10 is a schematic side elevational view of yet another exemplary embodiment of a prosthesis. [Figure 25C] FIG. 10 is a schematic side elevational view of yet another exemplary embodiment of a prosthesis. [Figure 26A] 1A-1C are diagrams illustrating another exemplary embodiment of a method for performing retrograde perfusion. [Figure 26B] 1A-1C are diagrams illustrating another exemplary embodiment of a method for performing retrograde perfusion. [Figure 27] 10A-10C are diagrams illustrating another exemplary embodiment of a prosthesis and a method for performing retrograde perfusion. [Figure 28A] FIG. 1 is a schematic diagram of the arteries of the leg. [Figure 28B] FIG. 1 is a schematic diagram of leg veins. [Figure 29] 1A-1C are schematic diagrams illustrating exemplary embodiments of an anastomosis device. [Figure 30] 1A-1C are schematic diagrams illustrating an exemplary embodiment of two blood vessels joined by an anastomosis device. [Figure 31A] 1A-1C are schematic diagrams illustrating an exemplary embodiment of an arteriovenous fistula stent separate from an exemplary embodiment of a venous stent. [Figure 31B] 1A-1C are schematic diagrams illustrating an exemplary embodiment of an arteriovenous fistula stent with an integrated venous stent. [Figure 31C] 1A-1C are schematic diagrams illustrating an exemplary embodiment of a fistula stent with an integrated venous stent. [Figure 32A] 11A-11C illustrate an exemplary method and apparatus for identifying and avoiding bifurcations 1104 in a percutaneous bypass procedure. [Figure 32B] 11A-11C illustrate an exemplary method and apparatus for identifying and avoiding bifurcations 1104 in a percutaneous bypass procedure. [Figure 32C] 11A-11C illustrate an exemplary method and apparatus for identifying and avoiding bifurcations 1104 in a percutaneous bypass procedure. [Figure 32D] 11A-11C illustrate an exemplary method and apparatus for identifying and avoiding bifurcations 1104 in a percutaneous bypass procedure. [Figure 33A] 1A-1C are diagrams illustrating schematically an exemplary procedure in which the following connection of a first blood vessel and a second blood vessel with a needle traversing interstitial tissue may be performed. [Figure 33B]1A-1C are diagrams illustrating schematically an exemplary procedure in which the following connection of a first blood vessel and a second blood vessel with a needle traversing interstitial tissue may be performed. [Figure 34A] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 34B] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 34C] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 34D] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 34E] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 34F] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 35A] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 35B] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 35C] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 35D] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 35E] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 35F] 1A-1C illustrate exemplary procedures that may be performed while a guidewire is in a blood vessel. [Figure 36A] 1A-1C illustrate an exemplary method for promoting retrograde perfusion of blood through veins to the toes. [Figure 36B] 1A-1C illustrate an exemplary method for promoting retrograde perfusion of blood through veins to the toes. [Figure 36C] 1A-1C illustrate an exemplary method for promoting retrograde perfusion of blood through veins to the toes. [Figure 36D] 1A-1C illustrate an exemplary method for promoting retrograde perfusion of blood through veins to the toes. [Figure 37A] 10A-10C illustrate an example of a valve disabler device in a radially expanded state. [Figure 37B] FIG. 37B is a flattened side view of the valve disabler of FIG. 37A. [Figure 37C] FIG. 37C is a close-up view of a flattened side view of the valve disabler of FIG. 37A in the area identified by circle 37C in FIG. 37B. [Figure 37D] FIG. 37B is an end view of the valve disabler device of FIG. 37A flattened as shown in FIG. 37B. [Figure 37E] FIG. 37B is an end view of the valve disabler device of FIG. 37A in a radially contracted state. [Figure 37F] FIG. 37B is a side view of the valve disabler device of FIG. 37A in a radially contracted state. [Figure 37G] 37B is another side view of the valve disabler device of FIG. 37A circumferentially rotated in a radially contracted state as compared to FIG. 37F. [Figure 37H] FIG. 37B is a side view of the valve disabler device of FIG. 37A in a radially expanded state. [Figure 37I] FIG. 37B is another side view of the valve disabler device of FIG. 37A radially expanded and circumferentially rotated as compared to FIG. 37H. [Figure 37J] 37J is a cross-sectional end view of the valve deactivation device of FIG. 37A in a radially expanded state taken along line 37J-37J of FIG. 37H. [Figure 37Ki] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Kii] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Li] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Lii] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Mi]37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Mii] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Ni] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 37Nii] 37B illustrates an exemplary procedure that may be performed using the valve disabler of FIG. 37A. [Figure 38A] 1A and 1B are schematic diagrams illustrating examples of the distal end of a catheter.

[0120] [Figure 38B] 38B illustrates an exemplary procedure that may be performed using the distal end of the catheter of FIG. 38A. [Figure 38C] 38B illustrates an exemplary procedure that may be performed using the distal end of the catheter of FIG. 38A. [Figure 38D] 38B illustrates an exemplary procedure that may be performed using the distal end of the catheter of FIG. 38A. [Figure 38Ei] 1A and 1B show examples of the distal end of a catheter. [Figure 38Eii] 1A and 1B show examples of the distal end of a catheter. [Figure 38F] FIG. 1 illustrates an example of a portion of a catheter. [Figure 38G] FIG. 10 shows another example of a portion of a catheter. [Figure 39A] 1 is a perspective view of an example portion of a target catheter. [Figure 39B] FIG. 39B is a side view of the target catheter of FIG. 39A in a first state. [Figure 39C] FIG. 39B is a side view of the target catheter of FIG. 39A in a second state. [Figure 39D] 39B is a schematic diagram illustrating an exemplary method of using the target catheter of FIG. 39A. [Figure 39E] 39B is a schematic diagram illustrating an exemplary method of using the target catheter of FIG. 39A. [Figure 39F]39B is a schematic diagram illustrating an exemplary method of using the target catheter of FIG. 39A. [Figure 39G] 39B is a schematic diagram illustrating an exemplary method of using the target catheter of FIG. 39A. [Figure 39H] 39B is a schematic diagram illustrating an exemplary method of using the target catheter of FIG. 39A. [Figure 39I] 39B is a schematic diagram illustrating an exemplary method of using the target catheter of FIG. 39A. [Figure 40A] 1 is a perspective view of an exemplary handle for deploying a tubular structure. [Figure 40B] FIG. 40B is an enlarged perspective cross-sectional view of a portion of the handle of FIG. 40A. [Figure 40C] FIG. 40B is a perspective view of the handle of FIG. 40A in an unfolded state. [Figure 40D] FIG. 40B is an enlarged perspective cross-sectional view of a portion of the handle of FIG. 40A in an unfolded state. [Figure 41A] 1 is a perspective view of an exemplary handle for deploying a tubular structure. [Figure 41B] FIG. 41B is an enlarged perspective, partially transparent view of a portion of the handle of FIG. 41A. [Figure 41C] 41B illustrates an exemplary method of operating the handle of FIG. 41A. [Figure 41Di] 41B illustrates an exemplary method of operating the handle of FIG. 41A. [Figure 41Dii] 41B illustrates an exemplary method of operating the handle of FIG. 41A. [Figure 41Ei] 41B illustrates an exemplary method of operating the handle of FIG. 41A. [Figure 41Eii] 41B illustrates an exemplary method of operating the handle of FIG. 41A. [Figure 41Eiii] 41B illustrates an exemplary method of operating the handle of FIG. 41A. [Figure 42A] FIG. 1 is a plan view of an exemplary embodiment of a launcher; [Figure 42B] 42B is a schematic top, side, and distal end perspective view of the distal portion of the launch device of FIG. 42A. [Figure 42Bi]1 is a schematic side view of an exemplary radiopaque marker. [Figure 42C] FIG. 42B is a schematic enlarged plan view of a distal portion of the launch device of FIG. 42A. [Figure 42Ci] 1 illustrates an exemplary catheter including a profile attached to a needle. [Fig. 42Cii] 1 illustrates an exemplary catheter including a profile attached to a needle. [Figure 42Ciii] 1 illustrates an exemplary catheter including a profile attached to a needle. [Figure 42D] FIG. 42B is a schematic side view of a distal portion of the launch device of FIG. 42A.

[0121] [Figure 43A] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43B] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43C] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43D] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43E] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43F] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43G] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43H] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43Hi] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43K] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43L] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43M] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43N] 42B is a schematic diagram illustrating an exemplary method of using a launcher including the distal portion of the launcher of FIG. 42A. [Figure 43Oi] FIG. 10 illustrates an example of an implementation of alignment using software. [Figure 43Oii] FIG. 10 illustrates an example of an implementation of alignment using software. [Figure 43Oiii] FIG. 10 illustrates an example of an implementation of alignment using software. [Figure 43Oiv] FIG. 10 illustrates an example of an implementation of alignment using software. [Figure 43Ov] FIG. 10 illustrates an example of an implementation of alignment using software. [Figure 43Ovi] FIG. 10 illustrates an example of an implementation of alignment using software. [Figure 44A] FIG. 1 is a schematic diagram illustrating an exemplary foot anatomy. [Figure 44B] FIG. 1 is a schematic diagram illustrating an exemplary foot anatomy. [Figure 44C] FIG. 1 is a schematic diagram illustrating an exemplary foot anatomy. [Figure 44D] FIG. 1 is a schematic diagram illustrating an exemplary foot anatomy. [Figure 44E] FIG. 1 is a schematic diagram illustrating an exemplary foot anatomy. [Figure 44F] FIG. 1 is a schematic diagram illustrating an exemplary foot anatomy. [Figure 45] FIG. 1 illustrates exemplary components of a kit that may be used for pedal access. [Figure 46A]1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46B] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46C] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46D] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46E] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46F] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46G] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46H] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46I] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46J] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 46K] 1A-1D illustrate an exemplary procedure for performing ascending venography. [Figure 47A] FIG. 1 is a perspective view of a portion of an exemplary cutting snare system. [Figure 47Bi] FIG. 1 is a side view of another exemplary cutting snare system. [Figure 47Bii] FIG. 1 is a side view of another exemplary cutting snare system. [Figure 47Ci] FIG. 1 is a side view of another exemplary cutting snare system. [Fig. 47Cii] FIG. 1 is a side view of another exemplary cutting snare system. [Figure 47Ciii] FIG. 1 is a side view of another exemplary cutting snare system. [Figure 47Civ] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Di] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Dii] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Diii] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Div] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Dv] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Ei] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Eii] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Eiii] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Eiv] FIG. 1 is a side view of another exemplary cutting snare system. [Figure 47Fi] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Fii] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Gi] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Gii] FIG. 10 is a side view of yet another exemplary cutting snare system. [Figure 47Giii] FIG. 10 is a side view of yet another exemplary cutting snare system. DETAILED DESCRIPTION OF THE INVENTION

[0122] Although several embodiments and examples are described below, the invention extends beyond the specifically disclosed embodiments and / or uses thereof and obvious modifications and equivalents thereof. The scope of the invention(s) disclosed herein is not intended to be limited by any particular embodiment(s) described below.

[0123] Minimally invasive procedures can provide access to a wider range of patient treatments, including those currently excluded from standard surgical procedures. One such procedure is percutaneous in situ coronary venous arterialization (PICVA), a catheter-based coronary artery bypass procedure in which a blockage in an affected artery is "bypassed" by creating a channel between the coronary artery and an adjacent coronary vein. In this way, arterial blood can be diverted into the venous system, perfusing cardiac tissue in a retrograde manner (retrograde perfusion), restoring blood supply to ischemic tissue. Some exemplary devices and methods for performing PICVA-like procedures are described in PCT Publication No. WO 99 / 049793 and U.S. Patent Application Publication No. 2004 / 0133225, both of which are incorporated herein by reference in their entireties.

[0124] To date, minimally invasive procedures for diverting blood flow from a coronary artery to an adjacent vein have had low success rates, often due to an inability to properly target the vein from the artery. Without appropriate systems and methods, such procedures (e.g., attempts to target veins using a combination of X-ray fluorescence and an imaging ultrasound probe positioned at the distal tip of a catheter, as described, for example, in U.S. Patent Application Publication No. 2004 / 0133225) often fail before they even begin. Indeed, such configurations can be difficult to navigate, and the limited location of the adjacent vein can require significant skill on the part of the clinician. Improvements in targeting systems and methods, such as the catheter-based systems and methods described herein, can enable procedures such as PICVA and transvascular procedures in general. Without such improvements, such percutaneous procedures will remain marginal to traditional open-heart surgical procedures and other types of bypass procedures.

[0125] This application describes, according to some embodiments, methods and systems useful in minimally invasive surgery that can reduce the workload of traditional surgery to treat conditions such as coronary heart disease and critical limb ischemia. For example, patients who would otherwise be unable to undergo surgery such as coronary artery bypass surgery or peripheral artery disease bypass surgery can be treated, and the degree of surgical trauma, risk of infection, and / or recovery time can be reduced or significantly reduced compared to traditional surgery.

[0126] FIG. 1 schematically illustrates an exemplary embodiment of a launching device 10 for directing a signal from a first body cavity 30 to a targeting device 20 in a second body cavity 35. The launching device 10 includes a signal transmitter 21. The launching device 10 may comprise, for example, a catheter having an elongated, flexible, rod-like portion and a tip portion, and may provide a conduit for delivering a treatment within a patient's body. The launching device 10 may be adapted for positioning and movement through a first body cavity or vessel 30 (e.g., a heart chamber, a coronary artery, a coronary vein, a peripheral artery, or a peripheral vein) within a patient's body. The elongated portion of the launching device 10 includes an outer sheath 11 enclosing a space that defines a lumen 13. The space within the lumen 13 may be appropriately segmented or subdivided as needed to define channels for delivering a treatment, controlling the positioning of the launching device 10, and the like. Such subdivision may be achieved, for example, axially, longitudinally, and concentrically.

[0127] The launcher 10 includes a signal transducer 12. The signal transducer 12 is configured to provide or emit a signal 40 that is directed outward from the launcher 10. In the embodiment shown in FIG. 1, the signal 40 is directed radially outward from the launcher 10 in a direction perpendicular to the longitudinal axis of the launcher 10. As will be described in more detail below, in some embodiments, the direction of the signal 40 need not be perpendicular to the longitudinal axis of the launcher 10, but can be directed at an angle relative to the longitudinal axis of the launcher 10. The signal transducer 12 can thereby form at least a portion of a signal generating means.

[0128] The signal transducer 12 is connected to a signal transmitter 50. The signal transmitter 50 may suitably be selected from an ultrasound or suitable electromagnetic source such as a laser, microwave radiation / illumination, radio waves, etc. In some embodiments, as described in further detail below, the signal transmitter 50 is configured to generate an ultrasound signal that is relayed to the signal transducer 12, which then directs the signal 40 from the first body cavity 30 into the surrounding tissue.

[0129] Targeting device 20 is positioned within an adjacent second body cavity or vessel 32 (e.g., a heart chamber, coronary artery, coronary vein, peripheral artery, peripheral vein) within the patient's body. First body cavity 30 and second body cavity 32 are separated by intervening tissue 34, sometimes referred to as interstitial tissue or a septum. First body cavity 30 and second body cavity 32 lie next to and parallel to one another along at least a portion of their respective lengths. For example, it is known that many of the veins and arteries in the body run parallel to one another along at least a portion of their entire lengths.

[0130] Targeting device 20 may be considered to be similar in configuration to launching device 10. For example, targeting device 20 may include a catheter having an elongated, flexible rod-like portion and a tip portion. In another example, fine movement and positioning of targeting device 20 within body cavity 32 may be achieved. In yet another example, targeting device 20 may include an outer sheath 21 surrounding a space that defines lumen 23. Lumen 23 may be suitably compartmentalized, for example, as in launching device 10.

[0131] The target device 20 includes a receiving transducer 22 configured to receive a signal 40 from the transducer 12 of the launcher 10. The receiving transducer 22 forms at least a part of a signal detection means. In use, upon receiving a signal 40 transmitted from the signal transducer 12, the receiving transducer 22 transmits the received signal to a signal detector 60. The signal detector 60 is configured to provide an output reading to a user of the system, for example, via an output display 61. The output display 61 may be a visual display, an audible display (e.g., beep or make some other sound upon receipt of a signal), etc.

[0132] In this manner, transmission and detection of directional signal 40 allows for manipulation and positioning of launcher 10 relative to target device 20. In use, launcher 10 and target device 20 can be manipulated by a user of the system until output display 61 indicates that signal 40 is being received by target device 40.

[0133] In some embodiments, the signal 40 includes or is an ultrasound 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 signal band widens with increasing distance from the signal transducer 12). Therefore, the accuracy of alignment between the launching device 10 and the target device 20 depends not only on signal detection but also on the distance between the two devices, since the signal beam width increases with increasing distance. This level of error is referred to as "position uncertainty." While there may be a certain tolerance level for position uncertainty, the degree of uncertainty should be reduced or minimized if treatment is to be accurately guided. For example, if the diameter d of the signal transducer 12 is 1 mm and the frequency of the ultrasound signal is 30 MHz, the position uncertainty x (e.g., the error limit on either side of the centerline) is 1 mm at a 5 mm vertical separation between the launching device 10 and the target device 20. For clinical applications, position uncertainty generally should not exceed about ±5 mm (for a total signal beamwidth of 10 mm at the point of reception). In some embodiments, 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, position uncertainty does not exceed about ±1 mm.

[0134] The strength of the signal 40 can be a factor in detection, with signal strength generally decreasing as the distance between the launching device 10 and the targeting device 20 increases. This distance is determined in part by the amount of intervening tissue 34 between the devices 10, 20. By way of example, if the signal 40 is an ultrasound signal, significant degradation of the signal can be expected if the launching device 10 and the targeting 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 affect the degradation of the signal 40 over distance (e.g., denser tissue degrades the signal more than less dense tissue).

[0135] The frequency of the ultrasonic signal can also affect the thickness of the signal transducer, which for a standard ultrasonic ceramic transducer (e.g., a piezoelectric transducer (PZT)) is 0.075 mm at 30 MHz.

[0136] FIG. 2 is a cross-sectional view taken along dotted line BB in FIG. 1. The correct orientation of the launcher relative to the target device can be a factor in detection, as the orientation line 41 can define where the treatment is to be administered. The clinical need for precise placement of treatment on the patient can be better served when the directional signal 40 is coupled to the treatment delivery means (e.g., parallel and longitudinally offset). For example, in this manner, a system user can administer treatment at the correct location by ensuring that the launcher 10 and target device 20 are properly positioned by transmitting and receiving the signal 40. The orientation line 41 in FIG. 2 indicates not only the direction of signal travel but also the path along which the treatment may be administered to the patient.

[0137] FIG. 3 schematically illustrates an exemplary embodiment of a launcher 10. The launcher 10 includes a signal transducer 120 oriented at an oblique angle relative to the longitudinal axis of the launcher 10. The signal 40 is transmitted at an angle relative to the direction of travel (e.g., forward travel, transverse travel) of the launcher 10 as it enters the body cavity 30 (FIGS. 1 and 2). In some embodiments, the beam angle is approximately perpendicular to the longitudinal axis of the launcher 10. In some embodiments, the beam angle is between about 20 degrees and about 60 degrees relative to normal, between about 30 degrees and about 50 degrees relative to normal, or about 45 degrees relative to normal, where 0 degrees corresponds to the longitudinal axis of the launcher 10 in the direction of travel.

[0138] Launching device 10 includes a hollow needle or cannula 17, which is an exemplary means for administering treatment. During advancement of launching device 10, hollow needle 17 is positioned in an undeployed or retracted state within lumen 13 of launching device 10. Hollow needle 17 can be deployed / expanded from launching device 10 via hole 16 in outer sheath 11 at a time deemed appropriate by the user (e.g., when signal 40 is detected by targeting device 20). Hole 16 can allow fluid communication between lumen 13 and body cavity 30 (FIG. 1). As shown by the exemplary embodiment of FIG. 3, hollow needle 17 can be advanced along a path that is parallel to the direction of signal 40. Hollow needle 17 can be used to puncture intervening tissue 34 (FIG. 1). In some embodiments, hollow needle 17 traverses the entire intervening tissue 34, allowing launching device 10 to access second body cavity 32 (FIG. 2). If desired, the pathway created by passage of hollow needle 17 through intervening tissue 34 can later be widened to allow fluid communication between first body cavity 30 and second body cavity 32 .

[0139] Therapeutic procedures suitable for use in some embodiments may include, for example, devices and / or instruments selected from the group consisting of cannulas, lasers, radiation emitting devices, probes, drills, blades, wires, needles, suitable combinations thereof, and the like.

[0140] In some embodiments, hollow needle 17 includes a sensor 19 that can help further determine positional information of the tip of hollow needle 17 relative to launch device 10. In some embodiments, sensor 19 is configured to detect changes in hydrostatic pressure. Other sensors suitable for use in the systems and methods described herein can include a temperature sensor, an oxygenation sensor, and / or a color vision sensor.

[0141] Optionally, hollow needle 17 can include an additional signal transducer 122. In the embodiment shown in FIG. 3, signal transducer 122 is positioned at one end of guidewire 14 near the tip of hollow needle 17. Signal transducer 122 can additionally or alternatively be positioned on hollow needle 17, if desired. In use, signal transducer 122 is driven by a short transmit pulse that generates a directional or non-directional signal pulse. The signal pulse can be detected by receiving transducer 22 attached to target device 20. The distance from guidewire 14 or hollow needle 17 to receiving transducer 22, and therefore target device 20, can be a time determined at least in part based on the delay between transmission of the signal pulse from signal transducer 122 and receipt of the signal pulse at receiving transducer 22.

[0142] FIG. 4 schematically illustrates an exemplary embodiment of a targeting device 20. In the embodiment illustrated in FIG. 4, the targeting device 20 is positioned within a body cavity 32. As described above, the targeting device 20 includes a receiving transducer 22 that receives a signal 40. The receiving transducer 22 can be unidirectional (e.g., capable of receiving signals from only one direction) or omnidirectional (e.g., capable of receiving signals from any direction). Arrow A indicates reverse blood flow after arterial-venous angiogenesis (also known as PICVA) has been performed. The targeting device 20 includes an omnidirectional ultrasound signal receiving transducer 60. An optional reflecting cone 601 can direct the signal 40 onto the disk-shaped receiving transducer 60. An acoustically transparent window 602 can separate the reflecting cone 601 from the receiving transducer 60. In some embodiments, an omnidirectional ultrasonic signal receiving transducer may be obtained by positioning a cylinder of flexible piezoelectric material, such as polyvinyl difluoride (PVDF), around the outer sheath of targeting device 20. In that way, the cylinder may act in a manner similar or equivalent to receiving transducer 60.

[0143] In the embodiment shown in FIG. 4, targeting device 20 includes an optional channel 25 for use in administering an agent, such as a therapeutic agent, to a patient. In some embodiments, channel 25 functions as a conduit to allow application of a blockage material 251 that acts to at least partially occlude or obstruct body cavity 32. Blockage material 251 may be suitably selected from gel-based materials. Blockage material 251 may additionally or alternatively include an embolic element (e.g., a balloon, a self-expanding stent, etc.). Placement of blockage material 251 may be guided by movement of targeting device 20. The presence of guide member 24 within lumen 23 of targeting device 20 may allow a user to precisely manipulate the position of targeting device 20 as desired.

[0144] Referring again to FIG. 2 , the launcher 10 includes a signal transducer 12 that can optionally be oriented so that the signal 40 is transmitted at an angle other than perpendicular to the signal transducer 12. FIG. 5 schematically illustrates another exemplary embodiment of the launcher 10. In some embodiments, for the exemplary launcher 10 shown in FIG. 5 , the signal transducer is in the form of a single-transducer array 123. The signal transducer array 123 includes a plurality of signal transducer elements 124 that can be oriented collectively to at least partially define a signal beamwidth and angle for the launcher 10. The smaller size of the elements 124 can allow the signal transducer array 123 to not occupy a significant portion of the lumen 13 of the launcher 10.

[0145] The embodiment shown in Figure 5 may be useful for ultrasound beamforming signal transmission. Figure 5 shows an array of signal transducer elements 124 separately connected to a transmitter 50 via delays 51, which allow the signals for each element 124 to be delayed relative to each other. The delays may provide or ensure that the ultrasound waveforms from each element 124 are aligned to generate an ultrasound beam 40 at a desired angle. In some embodiments, for example, where the signal 40 comprises visible light, an array of LEDs may additionally or alternatively be used.

[0146] 6 schematically illustrates an exemplary embodiment of a centering device for launching device 10 and / or targeting device 20. To aid in the process of aligning launching device 10 in first body cavity 30 and targeting device 20 in second body cavity 32, one or both of devices 10, 20 may include means for centering each device within its respective body cavity.

[0147] In some embodiments, the centering means comprises an inflatable bladder or balloon 111 that is positioned within the lumen 13, 23 when in an undeployed state and that can be inflated once the device 10, 20 reaches a desired location within the patient's body. The balloon 111 can be disposed on the exterior surface of the outer sheath 11, 21. The balloon 111 can be annular in shape so as to at least partially surround the device 10, 20 in a toroidal or donut-like fashion. The balloon 111 can be positioned to inflate on only one side of the device 10, 20 or on two opposing sides. As shown in FIG. 6, the balloon 111 is deployed on one side of the launch device 10.

[0148] In some embodiments, the centering means includes one or more loop structures 112 that, when in an undeployed or contracted state, are positioned within the lumen 13, 23 or within a recess formed in the outer sheath 11, 21. When the device 10, 20 reaches a desired location within the patient's body, the one or more loop structures 112 can expand radially outward from the device 10, 20, thereby centering the device 10, 20 within the body cavity 30, 32. Outward expansion of the loop structures 112 can be suitably achieved, for example, by compressing a length of wire so that it bows outward from the outer sheath 11, 21. A centering device employing this configuration can have multiple compressible lengths of wire or other suitable flexible material arranged in parallel, radially spaced apart positions around the circumference of the outer sheath 11, 21. Compression of the multiple wires can be facilitated by sliding members (not shown) positioned proximally and / or distally near both ends of the multiple wires. The sliding member is translatable along the longitudinal axis of the devices 10, 20. As shown in Figure 6, the targeting device 20 includes a fully deployed centering means 112 that allows the targeting device 20 to be centered within the body cavity 32.

[0149] Other possible means of centering the devices 10, 20 within the body lumens 30, 32 include, but are not limited to, expandable lantern devices, reversibly expandable stents, coils, helices, extendable probes or legs, combinations thereof, and the like.

[0150] In some embodiments, centering or other means (e.g., balloons, metal standoffs of various lengths, etc.) can be used to orient the device 10, 20 within the body cavity 30, 32 at or substantially off-center within the body cavity. For example, the device 10 can be oriented proximate the wall of the body cavity 30 where the needle 17 exits the body cavity 30, which can, for example, create a shorter ultrasound signal path and / or reduce errors due to the needle 17 traversing the intraluminal space. In another example, the device 10 can be oriented proximate the opposite wall of the body cavity 30 where the needle 17 exits the body cavity 30, which can, for example, create a firm surface for the needle 17 to press against. In yet another example, the device 20 can be oriented proximate the wall of the body cavity 32 where the needle 17 enters the body cavity 32, which can, for example, create a shorter ultrasound signal path. Other device orientations are also contemplated that are not located centrally or proximal to the vessel wall (e.g., only a portion of the diameter away from the wall and / or center of the lumen, such as 1 / 2, 1 / 3, 1 / 4, etc.).

[0151] example The methods and systems described herein, according to some embodiments, find particular utility in cardiovascular surgery. Some aspects are further illustrated by the following non-limiting example, in which the system is used by a clinician performing a connection of an artery to a vein (PICVA) to allow retrograde perfusion of cardiac tissue after occlusion of a coronary artery.

[0152] A launch catheter 10 is inserted into the blocked coronary artery using standard keyhole surgical techniques (e.g., tracking over a guidewire, tracking inside a guide catheter). A target catheter 20 is inserted into a coronary vein running parallel to the coronary artery using standard keyhole surgical techniques (e.g., tracking over a guidewire, tracking inside a guide catheter). The coronary vein is unobstructed, thus providing an alternative channel for blood flow to the myocardium, effectively bypassing the blockage in the coronary artery.

[0153] The launch catheter 10 includes a PZT ultrasound transducer 12 (available, for example, from CTS Piezoelectric Products of Albuquerque, New Mexico) oriented to transmit a directional ultrasound beam, in this example at a 45-degree angle (relative to the longitudinal axis of the launch device), preferably in the direction of blood flow within the artery 30, although other angles, including approximately 90 degrees, are contemplated. The ultrasound transducer 12 is activated, and in this example, a 30 MHz directional ultrasound signal 40 is transmitted from the launch catheter 10, although other frequencies are also contemplated. The target catheter 20 includes an omnidirectional ultrasound receiving transducer 60. To aid in determining the position of both the launch catheter 10 and the target catheter 20, both catheters 10, 20 include a centering or orienting means, in this example in the form of an annular inflatable balloon 111, although other centering or orienting means, or none at all, are contemplated. The centering means 111 on the launch catheter 10 is deployed by the clinician once the launch catheter 10 is deemed to be in the proper location near the site of the blockage within the coronary artery 30. This can be determined by standard fluoroscopic imaging and / or physical resistance. The target catheter 20 is then moved into the adjacent coronary vein 32 until a directional ultrasound signal 40 is detected by the signal-receiving transducer 60. To allow for more precise alignment of the launch catheter 10 and the target catheter 20, the centering means 111 on the target catheter 20 can be deployed before or after the signal 40 is detected.

[0154] Upon receiving the transmitted signal 40, the clinician can be confident that the launch catheter 10 and target catheter 20 are correctly positioned both rotationally and longitudinally within their respective blood vessels 30, 32 so that the arterial-venous connection procedure can begin. The target catheter 20 can be used to block blood flow within the coronary vein 32 by application of a gel blocking material 251 through a channel 25 in the target catheter 20. The blocking material 251 can be applied at a location within the coronary vein 32 that is downstream in terms of venous blood flow from the location of the signal-receiving transducer 60.

[0155] The clinician can then initiate the arterial-venous connection by deploying the hollow needle 17 from the launch catheter 10 substantially along a path parallel to and near 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 traverse a path that interrupts the path of the ultrasound signal at a point within the coronary vein 32. The hollow needle 17 optionally includes a sensor 19 near its tip configured to detect changes in hydrostatic pressure or Doppler flow to allow a user to monitor the transition from arterial to venous pressure as the hollow needle 17 passes through the two blood vessels 30, 32. The hollow needle 17 optionally includes a guidewire 14 within its lumen or lumen upon deployment. Once the hollow needle 17 and guidewire 14 have traversed the intervening tissue 34, the hollow needle 17 can be retracted back into the lumen 13 of the launch catheter 10, leaving the guidewire 14 in place. In some embodiments, once hollow needle 17 has traversed intervening tissue 34 , the user can separately thread guidewire 14 through the lumen or lumen of hollow needle 17 and retract needle 17 into launch catheter 10 .

[0156] The clinician withdraws the launch catheter 10 from the patient, leaving the guidewire 14 in place. An additional catheter device is then slid along the guidewire 14. FIG. 7 schematically illustrates a prosthesis 26, such as an expandable stent 26, in place, following a procedure such as arterial-venous revascularization. Further details regarding possible prostheses, including stents and stent-grafts, are provided below. The stent 26 can be deployed to open a perforation in the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, where the intervening arrow A indicates the direction of blood flow through the stent 26 between the first and second body lumens 30 and 32 (e.g., allowing arterial blood to be diverted into the venous system for retrograde perfusion of myocardial tissue). The stent 26 blocks upstream flow within the body lumen 32, forcing blood flow within the body lumen 32 in the same direction as blood flow within the body lumen 30. The graft material of stent 26 can form a fluid-tight lumen between body lumen 30 and body lumen 32. Target catheter 20 is withdrawn from the patient, leaving block material 251 in place. Optionally, as described in further detail herein, additional blocks or sutures can be inserted into the coronary vein to block or prevent backflow of arterial blood.

[0157] While the specific examples discussed above relate to cardiovascular surgery, the methods and systems described herein may have broad application in other surgical procedures. For example, any procedure involving the need to direct a treatment from one body cavity to another adjacent body cavity (e.g., for the treatment of peripheral arterial disease) may be considered. As such, applications in the fields of neurosurgery, urological surgery, and general vascular surgery may also be considered. The type of treatment need not limit the creation of a channel between body cavities. For example, the methods and systems described herein may be used to guide techniques such as catheter ablation, non-contact mapping of cardiac chambers, and drug delivery to precise body regions.

[0158] Several techniques for effectively bypassing an arterial blockage via percutaneous surgery have been described above. These techniques involve creating a channel or passageway between a first passageway, such as an artery, vein, or heart chamber upstream of the blockage, and a second passageway, such as an artery, vein, or heart chamber adjacent to the first passageway, and interconnecting the first and second passageways through a third passageway. Fluid, such as blood, can be diverted from the first passageway to the second passageway through the interconnecting third passageway. In embodiments where the first passageway includes an artery and the second passageway includes a vein, arterial blood can be perfused retrogradely into the tissue (retrograde perfusion).

[0159] As described above, an interconnecting passage between a first and a second body cavity passage can be created, for example, by deploying a needle outward from a first catheter positioned within the first passage, whereby the needle traverses the interstitial tissue, i.e., septum, between the first and second passages. A second catheter can be positioned in the second passage, providing a targeting device that receives signals, e.g., ultrasound signals, transmitted from the first catheter. By monitoring the received signals, the position of the first catheter relative to the second catheter can be determined to ensure that the needle is deployed in the correct position and orientation to create a passage for fluid flow between the first and second passages.

[0160] To provide or maintain blood flow through interconnected passages or channels, a structure having a lumen can be inserted into the passage to support interstitial tissue and / or inhibit or prevent the passage from closing. The tube can include, for example, a stent that is expanded within the channel using a balloon catheter, or a self-expanding stent, as described herein. A catheter for delivering the structure, e.g., a balloon catheter or a self-expanding catheter, can be guided within the channel by a guidewire deployed within the passage by a first catheter.

[0161] Passageways, such as arteries, veins, and heart chambers, can pulsate as the heart beats due to, for example, heart wall movement, peripheral limb movement, and / or fluctuations in pressure within the passageways themselves. This pulsation can cause the passageways to move relative to one another, which can place stresses on structures within the interconnecting passageways between them. This stress can be greater than the stress experienced by structures within a single passageway. The stresses can lead to premature failure of the structures, for example, through fatigue failure of stent struts. Failure of the structures can result in damage to interstitial tissue and / or occlusion of interconnecting passageways, which can lead to significant complications or complete failure of the treatment.

[0162] 8 illustrates a device, i.e., implant, or prosthesis 100 for providing or maintaining fluid flow through at least one passageway. The device 100 has a first or proximal end portion 102, a second or distal end portion 104, and an intermediate portion 106 between the proximal and distal end portions 102, 104. The device has an internal lumen 110 through which fluid passes through the device 100. The device 100, for example, at least the intermediate portion 106 of the device 100, includes a flexible polymer tube 108. The flexible polymer tube can at least partially define the lumen 110.

[0163] Device 100 has a support structure (e.g., at least one stent) including mesh 112 and mesh 114. In some embodiments, at least a portion of mesh 112 is embedded within the outer wall of vessel 108 adjacent to proximal end portion 102 of device 100. In some embodiments, at least a portion of mesh 114, e.g., wires or struts, is embedded within the outer wall of vessel 108 adjacent to distal end portion 104 of device 100. Meshes 112, 114 can comprise a biocompatible metal, such as stainless steel, and / or a shape memory material, such as nitinol or cobalt chrome.

[0164] The wire meshes 112, 114 can stiffen the end portions 102, 104, respectively. In some embodiments where the intermediate portion 106 does not include a mesh, the intermediate portion 106 can be relatively flexible compared to the end portions 102, 104 and / or the end portions 102, 104 can have a relatively high radial stiffness.

[0165] In some embodiments, the end portions 102, 104 of the device 100 are diametrically expandable. For example, the wire mesh 112, 114, after formation or manufacture, may have a smaller diameter than the passageway, e.g., blood vessel, within which the device 100 is deployed. Once the device 100 is in place within the passageway, the end portions 102, 104 may be expanded, i.e., deformed outward, thereby increasing the diameter of each end portion 102, 104 and abutting, e.g., the interior sidewall of the passageway. The end portions 102, 104 are configured to be maintained at the expanded diameter indefinitely by plastic deformation of the material (e.g., wire, struts) of the mesh 112, 114 and / or by means of a locking mechanism arranged to mechanically lock the mesh 112, 114 in the expanded position. The intermediate portion 106 of the device 100 may be diametrically expandable, e.g., by plastic deformation of the tube 108.

[0166] Figure 9 shows the device 100 of Figure 8 deployed to provide a fluid flow path between a first passageway 116 and a second passageway 118. The passageways 116, 118 can include coronary blood vessels, such as a coronary artery 116 and a coronary vein 118, or vice versa. The passageways 116, 118 can include peripheral blood vessels (e.g., blood vessels in the limbs), such as a femoral artery or other peripheral artery 116 and a femoral vein or other peripheral vein 118, or vice versa. The end portions 102, 104 and the intermediate portion 106 of the device 100 expand to meet and press against the interior walls of the passageways 116, 118. The distal end portion 104 of the device 100 is positioned within the second passageway 118, and the proximal end portion 102 of the device 100 is positioned within the first passageway 116. The intermediate portion 106 extends through a surgically formed opening or interconnecting passageway 130 between the passageways 116 and 118.

[0167] The enlarged end portions 102, 104 of the device 100 are resilient and exert an outward radial force against the inner walls of the passageways 116, 118. The radial rigidity of the end portions 102, 104 of the device 100 holds or locks the end portions 102, 104 in place within their respective passageways 116, 118, thereby preventing or reducing migration of the device 100 within the passageways 116, 118. In this manner, the end portions 102, 104 of the device 100 can lock or secure the device 100 in place while providing or maintaining fluid flow through the lumen 110 of the tube 108 ( FIG. 8 ) during use. In this manner, the device 100 can act as a shunt between the first passageway 116 and the second passageway 118.

[0168] The middle portion 106 of the device 100 can be flexible, for example, allowing the middle portion 106 to form an "S" shape formed by combining the first passageway 116, the second passageway 118, and the interconnecting passageway 130 (FIG. 9). The flexible middle portion 106 can allow the end portions 102, 104 of the device 100 to move relative to one another in response to relative movement of the passageways 116, 118.

[0169] In embodiments in which the intermediate portion 106 does not include a wire mesh but does include the flexible polymer material of the tube 108, the intermediate portion 106 may be less susceptible to damage due to mesh fatigue due to, for example, cyclic or other stresses imparted by relative movement of the passages 116, 118.

[0170] The intermediate portion 106 of the device 100 has sufficient elasticity to maintain the expansion of the interconnecting passage 130 so that the interconnecting passage 130 remains open to provide or maintain a path for blood flow from the artery 116 to the vein 118 by way of the lumen 110 of the tube 108 (FIG. 8). Blood flow from the artery 116 to the vein 118 by way of the interconnecting passage 130 can thereby be provided or maintained through the lumen 110 of the tube 108. The device 100 at least partially supports the artery 116, the vein 118, and the interconnecting passage 130 to provide a path for fluid communication through the device 100.

[0171] The proximal end portion 102 and the distal end portion 104 of the device 100 are configured such that when the distal end portion 104 of the device 100 is deployed within a vein 118 and the proximal end portion 102 of the device 100 is deployed within an artery 116, for example, as shown in FIG. 9 , the diameter of the expanded distal end portion 104 is sufficient to retain the distal end portion 104 within the vein 118, and the diameter of the expanded proximal end portion 102 is sufficient to retain the proximal end portion 102 within the artery 116. Thus, the diameter of the proximal end portion 102 can be different from the diameter of the distal end portion 104. By selecting appropriate diameters for the end portions 102, 104 and intermediate portion 106, the device 100 can be tailored to fit a particular anatomy and / or the anatomy of an individual patient.

[0172] For example, as shown in FIG. 9, an exemplary procedure will now be described in which the device 100 of FIG. 8 is positioned to provide a shunt between an occluded artery 116 and vein 118 (e.g., between a coronary artery 116 and a coronary vein 118, or between a peripheral artery 116 and a peripheral vein 118) to achieve retrograde perfusion of arterial blood.

[0173] A catheter can be inserted into the patient's arterial system through a small incision, usually made in the patient's groin area. The catheter is fed into the artery 116 and guided to a location upstream of the blockage, for example, adjacent to, parallel to, or substantially parallel to, the vein 118. A hollow needle is deployed from the catheter, through the wall of the artery 116, through the interstitial tissue 132 separating the artery 116 and vein 118, and through the wall of the vein 118. This path of the needle creates an interconnecting passageway or opening 130, allowing blood to flow between the artery 116 and vein 118. Needle deployment can be guided, for example, by a transmitter (e.g., a directional ultrasound transmitter) connected to a catheter in artery 116 and a receiver (e.g., an omnidirectional ultrasound receiver) connected to a catheter in vein 118, as described herein, or vice versa, by a receiver connected to a catheter in vein 116 and a transmitter connected to a catheter in artery 118, as in U.S. Patent Application No. 11 / 662,128. Other methods of forming opening 130 are also contemplated (e.g., using other types of guides as described herein, from vein to artery, with or without directional ultrasound guidance, etc.).

[0174] Before withdrawing the hollow needle from the passageway 130, a guidewire (e.g., as described with respect to guidewire 14 in FIG. 3) is threaded through the needle and inserted into the vein 118. The needle is then retracted, leaving the guidewire in place within the artery 116, passageway 130, and vein 118. The catheter carrying the needle can then be withdrawn from the patient's body. The guidewire can be used to further guide the catheter into the interconnecting passageway 130 between the artery 116 and vein 118.

[0175] A catheter carrying device 100 in an unexpanded state is advanced toward interconnecting passage 130, guided by a guidewire, e.g., via a rapid exchange lumen or through lumen 110. The catheter may include, for example, a balloon catheter configured to expand at least a portion of device 100 and / or a catheter configured to self-expand at least a portion of device 100. Distal end portion 104 of device 100 passes through interconnecting passage 130 and into vein 118, while proximal end portion 102 remains in artery 116. An intermediate portion 106 of device 100 is at least partially within passage 130 and at least partially within artery 116 and vein 118. Intermediate portion 106 bends to assume a curved or "S"-shaped configuration depending on the local anatomy. Such curvature allows the shape of the intermediate portion 106, which extends through the interconnecting passage 130 and optionally into at least one of the passages 116, 118, to conform to the shape of at least the interconnecting passage 130.

[0176] The distal end portion 104 of the device 100 is expanded, for example, by balloon inflation or by self-expansion, to increase the diameter of the distal end portion 104 and position the distal end portion 104 against the inner wall of the vein 118. The catheter can be adapted to expand the intermediate portion 106 of the device 100, for example, by balloon inflation, thereby widening or enlarging the interconnecting passageway 130 to allow blood flow (e.g., sufficient blood flow) from the artery 116 to the vein 118. The proximal end portion 102 of the device 100 is expanded, for example, by balloon inflation or by self-expansion, to increase the diameter of the proximal end portion 102 and position the proximal end portion 102 against the inner wall of the artery 116.

[0177] After expanding the end portions 102, 104 of the device 100, for example by self-expansion and / or balloon expansion, with or without augmented post-deployment expansion, the catheter and guidewire are withdrawn from the patient's body. In this manner, the device 100 is left in place or secured within the vein 118, artery 116, and interconnecting passageway 130, as shown in FIGURE 9. In embodiments in which the device 100 comprises a stent graft, the graft can form a fluid-tight passage between the artery 116 and the vein 118, thereby blocking such passageway and thereby inhibiting or preventing antegrade flow of blood within the vein 118, and the graft can be in addition to or instead of a blocking material within the vein 118.

[0178] The catheter can be adapted to selectively expand the proximal end portion 102, distal end portion 104, and / or intermediate portion 106 of device 100, individually or in combination, by action of, for example, two or more separate inflatable balloons or balloon portions, a single balloon configured to expand all portions of device 100 simultaneously, or a single balloon configured to expand one or more selected portions of device 100. For example, end portions 102, 104 can be self-expanding, while intermediate portion 106 can be expanded by a balloon to enlarge passageway 130. In some embodiments involving balloon expansion, all or selected portions of device 100 can be expanded, for example, simultaneously by a balloon spanning the entire length of device 100, by multiple balloons spaced longitudinally to selectively expand selected portions of device 100, and / or sequentially by a single balloon or multiple balloons. In some embodiments involving at least partial self-expansion, all or selected portions of device 100 can be expanded, for example, by proximally retracting a sheath covering or surrounding device 100, thereby deploying device 100 from distal to proximal as the sheath is retracted proximally. Proximal-to-distal deployment of device 100 is also possible, as well as intermediate and then end-to-end deployment. In some embodiments, for example, in which device 100 is at least partially conical or tapered, device 100 can be at least partially expanded using a conical or tapered balloon. In some such embodiments, the portion of the balloon proximal to vein 118 can be larger in diameter than the portion of the balloon proximal to artery 116, so that, for example, device 100 can be adapted to change the diameter of the vein with any increase in pressure or blood flow within vein 118.

[0179] The procedure may also include other steps. For example, prior to deploying device 100, a balloon catheter may be guided into interconnecting passageway 130 and positioned so that the inflatable balloon portion of the catheter is within interconnecting passageway 130. When the balloon is inflated, it presses against the walls of interconnecting passageway 130, widening or expanding interconnecting passageway 130 to facilitate subsequent insertion of device 100.

[0180] 10 illustrates another device 134 for providing fluid flow through at least one passageway. The device 134 includes a mesh 136 and a polymer tube 108. While the mesh 136 is shown as being on the exterior of the polymer tube 108, it may additionally or alternatively be on the interior of the polymer tube and / or within the polymer tube 108, as described herein. As described with respect to the device 100, the device 134 includes a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. In the embodiment illustrated in FIG. 10, the mesh 136 extends along the entire length of the device 134, including along the intermediate portion 106.

[0181] 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 vary, and / or the window size pattern of a cut mesh can vary.

[0182] In some embodiments, the spacing can be relatively small at the proximal and distal end portions 102, 104 and relatively large at the intermediate portion 106. In other words, the density or fenestration size of the mesh 136 can be relatively small at the intermediate portion 106 and relatively large at the end portions 102, 104. In some such embodiments, the intermediate portion 106 can be more flexible than the end portions 102, 104. The relatively stiff end portions 102, 104 can engage and remain within a passageway. While the mesh 136 in the intermediate portion 106 may be subjected to stresses, such as cyclic stresses, during use, the relatively high flexibility of the intermediate portion 106 due to its lower density or fenestration size allows the intermediate portion 106 to flex in response to the stress and thus experience a smaller impact. Therefore, the risk of fatigue failure of the device 134, and particularly of the filaments or struts 138 of the mesh 136, can be reduced compared to a device having uniform flexibility along its entire length.

[0183] In some embodiments, the spacing can be relatively large at the proximal and distal end portions 102, 104 and relatively small at the intermediate portion 106. In other words, the density of the mesh 136 can be relatively high (or the window size of the mesh 136 can be relatively small) at the intermediate portion 106 and relatively small (or the window size of the mesh 136 can be relatively large) at the end portions 102, 104. In some such embodiments, the intermediate portion 106 can have sufficient radial stiffness to inhibit or prevent collapse of the passageway 130, yet still be flexible enough to flex in response to stress, such as cyclic stress. The end portions 102, 104 can engage and reside within the passageway.

[0184] 11 illustrates another device, i.e., implant or prosthesis 140, that provides for fluid flow through at least one passageway. As described with respect to device 100, device 140 has a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. Device 140 comprises a polymer tube 108 and a support structure having a first mesh 142 and a second mesh 144. First mesh 142 extends from proximal end portion 102 toward (e.g., into) intermediate portion 106 and, optionally, into distal end portion 104. Second mesh 144 extends from distal end portion 104 toward (e.g., into) intermediate portion 106 and, optionally, into proximal end portion 102. Meshes 142, 144 thereby overlap one another at least at intermediate portion 106. The meshes 142, 144 can both be on the outside of the tube 108, on the inside of the tube 108, or embedded within the tube 108, or one mesh can be on the outside of the tube 108, on the inside of the tube 108, or embedded within the tube 108, while the other mesh is on a different side of the tube 108, on the inside of the tube 108, or embedded within the tube 108 (e.g., one mesh is on the inside of the tube 108 and the other mesh is on the outside of the tube 108). The meshes 142, 144 can be formed, for example, by braiding wire in a lattice configuration around or inside the polymer tube 108, by placing cut tubes around or inside the polymer tube 108, by being embedded within the polymer tube 108, combinations thereof, etc.

[0185] In some embodiments, the density of the meshes 142, 144 is relatively high at their respective end portions 102, 104 (i.e., the window size of the meshes 142, 144 is relatively small) and decreases in density (i.e., the window size increases) toward the middle portion 106. The overall braid density (e.g., the braid density of both meshes 142, 144 joined together) can be lower in the middle portion 106 than in the end portions 102, 104, i.e., the overall window size (e.g., the window size of both meshes 142, 144 joined together) can be larger in the middle portion 106 than in the end portions 102, 104. In some such embodiments, the middle portion 106 is relatively flexible compared to the end portions 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 end portions 102, 104. In some embodiments, as the window size increases (e.g., longitudinally along the tapered portion of the device 140), the density decreases, the mesh coverage decreases, and / or the porosity increases because the width of the struts and / or filaments remains substantially constant or constant or does not increase at the same rate as the window size, which can result in changes in flexibility along the longitudinal length.

[0186] The first mesh 142 and the second mesh 144 can comprise different materials, which can allow the respective properties of each distal end portion 102 and proximal end portion 104 of the device 140 to be optimized for a particular application of the device 140. For example, the second mesh 144 at the distal end portion 104 of the device 140 can comprise a relatively flexible metal alloy to facilitate insertion into an interconnecting passage between two blood vessels, while the first mesh 142 at the proximal end portion 102 of the device 140 can comprise a relatively inelastic metal alloy to provide a high degree of resistance to the proximal end portion 104 to securely hold the device 140 in place. The first mesh 142 and the second mesh 144 can have the same material composition (e.g., both comprising Nitinol) but different wire diameters (gauges) or strut thicknesses.

[0187] FIG. 12 illustrates another device, i.e., implant or prosthesis 150, that provides fluid flow through at least one passageway. The device 150 includes a support structure (e.g., a stent) 152 and a graft 154. As described with respect to the device 100, the device 150 includes a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. The proximal end portion 102 includes a cylindrical or substantially cylindrical portion, and the distal end portion 104 includes a cylindrical or substantially cylindrical portion. The diameter of the proximal end portion 102 is smaller than the diameter of the distal end portion 104. In some embodiments, the diameter of the proximal end portion 102 is larger than the diameter of the distal end portion 104. The intermediate portion 106 has a tapered or frustoconical shape between the proximal end portion 102 and the distal end portion 104. The stent 152 can include filaments (e.g., woven, layered), cut tubes, or cut sheets, and / or combinations thereof.

[0188] The parameters of the stent 152 may be uniform or substantially uniform across a portion and / or multiple portions, or may vary within a portion and / or between multiple portions. For example, the stent 152 may comprise a cut tube or cut sheet at the proximal end portion 102, the stent 152 may comprise a cut tube or cut sheet at the distal end portion 102, and the stent 152 may comprise filaments (e.g., woven or layered) at the intermediate portion 106. Some such embodiments may provide superior placement by the proximal end portion 102 and the distal end portion 104, and superior flexibility of the intermediate portion 106 (e.g., adaptability to third passageway sizes and dynamic stresses).

[0189] The stent 152 can include different materials in different portions. For example, the stent 152 can include cobalt chromium and / or tantalum in the proximal end portion 102, the stent 152 can include nitinol in the distal end portion 104, and the stent 152 can include nitinol in the intermediate portion 106. Some such embodiments can provide superior placement and / or wall apposition by the device 150 in each deployment region (e.g., the proximal end portion 102 engaging the sidewall of the artery, the distal end portion 104 engaging the sidewall of the vein, and the intermediate portion 106 engaging the sidewall of the passageway between the artery and the vein). In some embodiments in which the distal end portion 104 is self-expanding, the distal end portion 104 can adapt by changing the vessel diameter, for example, by further self-expanding (e.g., if the vein diameter increases due to increased pressure or blood flow).

[0190] Combinations of support structure materials and types are also contemplated. For example, the stent 152 may comprise a cut tube or sheet comprising cobalt chromium and / or tantalum in the proximal portion, the stent 152 may comprise a cut tube or sheet comprising nitinol in the distal end portion 104, and the stent 152 may comprise a filament comprising nitinol in the intermediate portion 106.

[0191] In embodiments, the stent 152 has at least a portion comprising a cut tube or sheet, and the cut pattern may be the same. For example, the cut pattern may be the same in the proximal end portion 102 and the distal end portion 104, but varies proportionally with the change in diameter. In some embodiments, the fenestration size or strut density is uniform or substantially uniform within the portions 102, 104, 106, within two or more of the portions 102, 104, 106, and / or from one end of the stent 152 to the other end of the stent 152. In embodiments in which the stent 152 has at least one portion comprising a filament, the number of turns may be the same. For example, the number of turns may be the same in the proximal end portion 102 and the distal end portion 104, but varies with the change in diameter. In some embodiments, the winding density or porosity is uniform or substantially uniform within sections 102, 104, 106, within two or more of sections 102, 104, 106, and / or from one end of stent 152 to the other end of stent 152. In embodiments in which stent 152 has at least one section comprising cut tube or sheet and at least one section comprising filament, the cut pattern and windings may be configured to achieve a uniform or substantially uniform density. Non-uniformities are also possible, for example, as described herein.

[0192] The graft 154 may include materials such as those described for the tube 108 and attachment to the stent 152. The graft 154 generally forms a fluid-tight passageway through at least a portion of the device 150. Although the graft 154 is shown as being only around the mid-section 106, it may extend the entire length of the device 150 or may overlap partially within at least one of the cylindrical end sections 102, 104.

[0193] FIG. 13 illustrates another device 160 for providing fluid flow through at least one passageway. The device 160 includes a support structure (e.g., a stent) and a graft 164. As described with respect to the device 100, the device 160 includes a proximal end portion 102, a distal end portion 104, and an intermediate portion 106. The proximal end portion 102 includes a tapered or frustoconical portion, and the distal end portion 104 includes a tapered or frustoconical portion. The diameter of the proximal end of the proximal end portion 102 is smaller than the diameter of the distal end of the distal end portion 104. In some embodiments, the diameter of the proximal end of the proximal end portion 102 is larger than the diameter of the distal end of the distal end portion 104. The intermediate portion 106 includes a tapered or frustoconical shape between the proximal end portion 102 and the distal end portion 104. In some embodiments, the bevel angles of portions 102, 104, 106 are the same or substantially the same (e.g., as shown in FIG. 13 ). In some embodiments, the bevel angle of at least one portion is sharper, i.e., narrower, than at least one other portion. The frustoconical proximal and distal end portions 102, 104 can enable better placement within a body passageway because, for example, arteries taper away from the heart and veins taper toward the heart, and end portions 102, 104 can be configured to at least partially correspond to such anatomical tapers.

[0194] Figure 12 shows a device 150 having a first cylindrical or straight portion, a conical or tapered portion, and a second cylindrical or straight portion. Figure 13 shows a device 160 having one or more conical or tapered sections (e.g., the entire device 160 is conical or tapered or has multiple conical or tapered sections). In some embodiments, combinations of devices 150, 160 are possible. For example, a device may have a cylindrical or straight portion and the remainder of the device may have a conical or tapered portion. In some such embodiments, the device can have a length of about 1 cm to about 10 cm (e.g., about 5 cm) and have a cylindrical or straight portion having a diameter of about 1 mm to about 5 mm (e.g., about 3 mm) and a length of about 0.5 cm to about 4 cm (e.g., about 2 cm), and a conical or tapered portion having a diameter that gradually increases from the diameter of the cylindrical or straight portion to a diameter of about 3 mm to about 10 mm (e.g., about 5 mm) and a length of about 1 cm to about 6 cm (e.g., about 3 cm). Such devices may not have a separate cylindrical or conical portion following them.

[0195] As described above with respect to support structure 152, support structure 162 can include filaments (eg, woven, layered), cut tubes or sheets, the same material, different materials, and combinations thereof.

[0196] The graft 164 may include materials such as those described for the tube 108 and attachment to the stent 162. The graft 164 generally forms a fluid-tight passageway through at least a portion of the device 160. Although the graft 164 is shown as being only around the mid-section 106, it may extend the entire length of the device 160 or may overlap partially within at least one of the frusto-conical end sections 102, 104.

[0197] In some embodiments, a combination of device 150 and device 160 may be contemplated. For example, proximal end portion 102 may be cylindrical or substantially cylindrical (e.g., as in device 150), and distal end portion 104 may be tapered or frustoconical (e.g., as in device 160), with proximal end portion 102 having a larger diameter than the distal end of distal end portion 104. In another example, proximal end portion 102 may be tapered or frustoconical (e.g., as in device 160), and distal end portion 104 may be cylindrical or substantially cylindrical (e.g., as in device 150), with the proximal end of proximal end portion 102 having a larger diameter than the distal end portion 104. In each example, intermediate portion 106 may have a tapered or frustoconical shape between proximal end portion 102 and distal end portion 104.

[0198] Exemplary deployment devices for the implantable devices described herein are described in U.S. Patent Application No. 12 / 545,982, filed August 24, 2009, and U.S. Patent Application No. 13 / 486,249, filed June 1, 2012, the entire contents of each of which are incorporated herein by reference. The device generally has a handle with a user-actuable trigger at its proximal end and a combination of tubular members at its distal end configured to be pushed and / or pulled upon actuation of the trigger to release the device. Other delivery devices are also contemplated. The delivery device may have a portion slidable over a guidewire (e.g., manipulated between an artery and a vein by a tissue-crossing needle) and / or may be trackable through a lumen of a catheter.

[0199] While several embodiments and examples have been shown or described in detail herein, various combinations, subcombinations, modifications, variations, substitutions and omissions of specific features and aspects of those embodiments are possible, some of which are described herein by way of example only.

[0200] The device, e.g., the stent of the device, the mesh of the device, the support structure of the device, etc., can be self-expanding. For example, the mesh can include a shape-memory material, such as nitinol, that can return to a preset shape after being deformed. In some embodiments, the stent can be fabricated into a desired shape in its expanded configuration and can be compressed to fit inside a sleeve for delivery to a vascular site through a catheter. To deploy and expand the stent, the sleeve is retracted from the stent, allowing the shape-memory material to return to its preset shape, thereby depositing the stent within the passageway and, if the stent has sufficient radial strength, enlarging the passageway. The use of a balloon catheter is not required to expand a fully self-expanding stent, but can be used, for example, to enhance or optimize deployment.

[0201] The device can have one or more self-expanding portions and one or more portions that are expandable by deformation, for example, with a balloon catheter. For example, in the embodiment shown in Figure 11, the first mesh 142 can comprise stainless steel that is expandable with a balloon catheter, and the second mesh 144 can comprise nitinol to self-expand upon expansion.

[0202] For any of the embodiments described herein, the polymer tube 108 carrying the graft 154, 164 can comprise any suitable compliant or flexible polymer, such as PTFE, silicone, polyethylene terephthalate (PET), polyurethanes such as polycarbonate-based aromatic biodurable thermoplastic polyurethane elastomers (e.g., ChronoFlex C® 80A and 55D Medical Grade, available from AdvanSource Biomaterials, Inc., Wilmington, Massachusetts), combinations thereof, etc. The polymer tube 108 can comprise a biodegradable, bioabsorbable, or biocompatible polymer (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycollactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.). The polymer can be in tubular form prior to interacting with the support structure (e.g., a stent), or can be formed on, within, and / or around the support structure (e.g., a stent). For example, the polymer can comprise spun fibers, dip coatings, combinations thereof, etc. In some embodiments, the device may omit the tube, for example, if the device is to be deployed within a single blood vessel. In some such embodiments, the middle portion of the stent may have a mesh with a lower winding density or a larger fenestration size, while the end portions of the stent have a mesh with a higher winding density or a smaller fenestration size, and the mesh is generally tubular to define a path for fluid flow through the center of the mesh. In some embodiments, the polymer tube 108 has a lip (e.g., comprising the same or a different material), which can help form a fluid-tight seal between the polymer tube 108 and the body passageway. The seal may be angled, for example, for angled positioning of the polymer tube 108 between the body passageways. In some embodiments, the polymer tube 108 may extend longitudinally beyond the support structure in at least one direction, with the extending portion being supported by the support structure.

[0203] The mesh can comprise any suitable material, such as nickel, titanium, chromium, cobalt, tantalum, platinum, tungsten, iron, manganese, molybdenum, combinations thereof (e.g., nitinol, cobalt chromium, stainless steel), etc. The mesh can comprise a biodegradable, bioabsorbable, or biocompatible polymer (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycollactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.) and / or glass, and can be metal-free. As discussed above with reference to FIG. 11 , for example, different materials can be used in several portions of the mesh or within the same mesh. For example, mesh 114 at distal end portion 104 and mesh 112 at proximal end portion 102 of device 100 can comprise different materials. For another example, mesh 112 and / or mesh 114 may comprise various types of metal alloys (e.g., a shape memory alloy combined with a non-shape memory alloy, a first shape memory alloy combined with a second shape memory alloy different from the first shape memory alloy, a metal alloy (e.g., including cobalt, chromium, nickel, titanium, combinations thereof, etc.) combined with a cladding material (e.g., including a core comprising a radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc.)), and / or a non-metallic material such as a polymer (e.g., polyester fiber), carbon, and / or bioabsorbable glass fiber. In some embodiments, at least one mesh 112, 114 comprises nitinol and stainless steel. Nitinol may allow for some self-expansion (e.g., partial and / or complete self-expansion), in which case the mesh may be further expanded, for example, using a balloon.

[0204] While generally shown in Figures 8, 10, and 11 as a woven filament mesh, any other structure capable of providing the desired degree of elasticity can be used. For example, layers of counter-wound filaments can be fused at both ends of the filaments to provide an expandable structure. In another example, a metal sheet can be cut (e.g., laser cut, chemically etched, plasma cut, etc.) to form perforations and then heat-set into a tubular former, or a metal tube (e.g., hypotube) can be cut (e.g., laser cut, chemically etched, plasma cut, etc.) to form perforations. Cut tubes (including cut sheets rolled into tubes) can be heat-set to provide an expanded configuration.

[0205] The filaments, wires, or ribbons, which can be woven, braided, layered, or otherwise configured, are generally elongated and have a cross-section that is circular, oval, square, rectangular, etc. Exemplary nonwoven filaments can have a first layer of filaments wound in a first direction and a second layer of filaments wound in a second direction, with at least some of the filament ends joined together (e.g., by bonding to an expandable ring). Exemplary braid patterns include one over one, two over one, two over two, and / or combinations thereof, although other braid patterns are also contemplated. At filament intersections, the filaments can be helically wound, can cross in a sliding relationship, and / or combinations thereof. The filaments can be loose (e.g., held together by braiding), and / or can be joined by a weld, sleeve, or other joining element, and / or combinations thereof. The ends of the filaments can be recurved, crimped into rings (e.g., end crimped with a radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc., which can also act as radiopaque markers), twisted, ball welded, combinations thereof, etc. The woven ends can include filament ends and / or recurved filaments and can have open cells, secured or unsecured filaments, welds, adhesives or other fusing means, radiopaque markers, combinations thereof, etc. The filament parameters can be uniform or substantially uniform across a portion and / or multiple portions, or can vary within a portion and / or between multiple portions. For example, the proximal end portion 102 can have first parameters and the distal end portion 104 can have second parameters that differ from the first braid pattern. As another example, the proximal end portion 102 and the distal end portion 104 may each have a first parameter, and the intermediate portion 106 may have a second parameter that is different from the first parameter. As yet another example, at least one of the proximal end portion 102, the distal end portion 104, and the intermediate portion 106 may have both a first parameter and a second parameter that is different from the first parameter.Filament parameters can include, for example, filament type, filament thickness, filament material, amount of filaments, weave pattern, layering, winding direction, pitch, angle, cross type, filament bonding or lack thereof, filament end treatment, weave end treatment, layered end treatment, amount of layers, presence or absence of welds, radiopacity, braid pattern, density, porosity, filament angle, braid diameter, winding diameter, and shape setting.

[0206] The tube or sheet can be cut to form a strut or cell pattern, with the struts being the portions of the tube or sheet that remain after cutting and the cells, perforations, or windows being the cut-out portions. The tube (e.g., hypotube) can be cut directly, or the sheet can be cut and then rolled into a tube. The tube or sheet can be in a set shape before cutting or after cutting. The tube or sheet can be welded or otherwise bonded to itself, another tube or sheet, a filament, a graft material, etc. Cutting can be done with a laser, a chemical etchant, a plasma, combinations thereof, etc. Exemplary cut patterns include helical spirals, woven braids, coils, individual rings, continuous rings, open-celled cells, closed-celled cells, combinations thereof, etc. In embodiments involving continuous rings, the rings can be connected using flexible connectors, non-flexible connectors, and / or combinations thereof. In embodiments including continuous rings, the connectors of the rings (e.g., flexible, inflexible, and / or combinations thereof) intersect the peaks of the rings, the valleys of the rings, the intermediate portions of the struts, and / or combinations thereof (e.g., peak to peak, valley to valley, intermediate to intermediate, peak to valley, peak to intermediate, valley to intermediate, valley to peak, intermediate to peak, intermediate to valley). The tubes, sheets, or sections may be ground and / or polished before or after cutting. Internal ridges may be formed, for example, to aid in fluid flow. The parameters of the cut tubes or sheets may be uniform or substantially uniform across a portion and / or multiple portions, or may vary within a portion and / or between multiple portions. For example, the proximal end portion 102 may have a first parameter and the distal end portion 104 may have a second parameter that is different from the first parameter. As another example, the proximal end portion 102 and the distal end portion 104 may each have a first parameter, and the intermediate portion 106 may have a second parameter that is different from the first parameter. As yet another example, at least one of the proximal end portion 102, the distal end portion 104, and the intermediate portion 106 may have both a first parameter and a second parameter that is different from the first parameter.Cut tube or sheet parameters may include, for example, radial strut thickness, circumferential strut width, strut shape, cell shape, cut pattern, cut type, material, density, porosity, tube diameter, and shape settings.

[0207] In some embodiments, the perforations may result in a mesh having a relatively flexible middle portion and relatively stiff end portions. Alternatively, the support structure may be an open-cell foam disposed within the tube.

[0208] The filaments, stent-grafts, or portions thereof of a stent, and / or struts, stent-grafts, or portions thereof of a cut stent may be surface modified to carry a drug such as, for example, a thrombosis modifier, a fluid flow modifier, an antibiotic, etc. The filaments, stent-grafts, or portions thereof of a stent, and / or struts, stent-grafts, or portions thereof of a cut stent may be at least partially covered by a coating including a drug such as a thrombosis modifier, a fluid flow modifier, an antibiotic, etc. embedded in, for example, a polymer layer or a series of polymer layers that may be the same as or different from the polymer tube 108.

[0209] The thickness (e.g., diameter) of the filaments of the stent, stent graft, or portion thereof, and / or struts of the cut stent, stent graft, or portion thereof, may be from about 0.0005 inches to about 0.02 inches, from about 0.0005 inches to about 0.015 inches, from about 0.0005 inches to about 0.01 inches, from about 0.0005 inches to about 0.008 inches, from about 0.0005 inches to about 0.007 inches, from about 0.0005 inches to about 0.006 inches, from about 0.0005 inches to about 0.005 inches, or from about 0.0005 inches to about 0.004 inches. about 0.0005 inches to about 0.003 inches, about 0.0005 inches to about 0.002 inches, about 0.0005 inches to about 0.001 inches, about 0.001 inches to about 0.02 inches, about 0.001 inches to about 0.015 inches, about 0.001 inches to about 0.01 inches, about 0.001 inches to about 0.008 inches, about 0.001 inches to about 0.007 inches, about 0.001 inches to about 0.006 inches, about 0.001 inches to about 0.005 inches, about 0.001 inches to about 0.004 inches, about 0.001 inches to about 0.003 inches, about 0.001 inches inches to about 0.002 inches, about 0.002 inches to about 0.02 inches, about 0.002 inches to about 0.015 inches, about 0.002 inches to about 0.01 inches, about 0.002 inches to about 0.008 inches, about 0.002 inches to about 0.007 inches, about 0.002 inches to about 0.006 inches, about 0.002 inches to about 0.005 inches, about 0.002 inches to about 0.004 inches, about 0.002 inches to about 0.003 inches, about 0.003 inches to about 0.02 inches, about 0.003 inches to about 0.015 inches, about 0.003 inches to about 0.01 inches, 0.003 inches to about 0.008 inches, about 0.003 inches to about 0.007 inches, about 0.003 inches to about 0.006 inches, about 0.003 inches to about 0.005 inches, about 0.003 inches to about 0.004 inches, about 0.004 inches to about 0.02 inches, about 0.004 inches to about 0.015 inches, about 0.004 inches to about 0.01 inches, about 0.004 inches to about 0.008 inches, about 0.004 inches to about 0.007 inches, about 0.004 inches to about 0.006 inches, about 0.004 inches to about 0.005 inches, about 0.005 inches to about 0.0.02 inches, about 0.005 inches to about 0.015 inches, about 0.005 inches to about 0.01 inches, about 0.005 inches to about 0.008 inches, about 0.005 inches to about 0.007 inches, about 0.005 inches to about 0.006 inches, about 0.006 inches to about 0.02 inches, about 0.006 inches to about 0.015 inches, about 0.006 inches to about 0.01 inches, about 0.006 inches to about 0.008 inches, about 0.006 inches to about 0.007 inches The thickness may be about 0.007 inches to about 0.02 inches, about 0.007 inches to about 0.015 inches, about 0.007 inches to about 0.01 inches, about 0.007 inches to about 0.008 inches, about 0.008 inches to about 0.02 inches, about 0.008 inches to about 0.015 inches, about 0.008 inches to about 0.01 inches, about 0.01 inches to about 0.02 inches, about 0.01 inches to about 0.015 inches, or about 0.015 inches to about 0.02 inches. Other thicknesses are contemplated, including thicknesses greater or less than those specified. Filaments and / or struts comprising some materials (e.g., biodegradable materials, low resilience materials, etc.) may be thicker than those specified.

[0210] The thickness of the filaments and / or struts can be based on, for example, at least one of the device or device portion size (e.g., diameter and / or length), porosity, radial strength, material, amount of filaments and / or struts, cut pattern, weave pattern, layering pattern, etc. For example, larger filament and / or strut thicknesses (e.g., greater than about 0.006 inches) may be useful for larger devices or device portions used to treat larger vessels such as coronary vessels, intermediate filament and / or strut thicknesses (e.g., from about 0.003 inches to about 0.006 inches) may be useful for medium-sized devices or device portions used to treat medium-sized vessels such as peripheral vessels, and small filament and / or strut thicknesses (e.g., less than about 0.003 inches) may be useful for smaller devices or device portions used to treat smaller vessels such as veins and neurovasculature.

[0211] The inner or outer diameter of a stent, stent graft, or first end portion, second end portion, intermediate portion, or sub-portion of a stent, taking into account, for example, the thickness of the filaments or struts, can be about 1 mm to about 12 mm, about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 6 mm, about 1 mm to about 4 mm, about 1 mm to about 2 mm, about 2 mm to about 12 mm, about 2 mm to about 10 mm, about 2 mm to about 8 mm, about 2 mm to about 6 mm, about 2 mm to about 4 mm, about 4 mm to about 12 mm, about 4 mm to about 10 mm, about 4 mm to about 8 mm, about 4 mm to about 6 mm, about 6 mm to about 12 mm, about 6 mm to about 10 mm, about 6 mm to about 8 mm, about 8 mm to about 12 mm, about 8 mm to about 10 mm, or about 10 mm to about 12 mm. Some such diameters may be suitable, for example, for treating coronary vessels. The inner or outer diameter of a stent, stent graft, or portion of a stent, taking into account, for example, the thickness of the filaments or struts, can be about 1 mm to about 10 mm, about 1 mm to about 8 mm, about 1 mm to about 6 mm, about 1 mm to about 4 mm, about 1 mm to about 2 mm, about 2 mm to about 10 mm, about 2 mm to about 8 mm, about 2 mm to about 6 mm, about 2 mm to about 4 mm, about 4 mm to about 10 mm, about 4 mm to about 8 mm, about 4 mm to about 6 mm, about 6 mm to about 10 mm, about 6 mm to about 8 mm, or about 8 mm to about 10 mm. Some such diameters may be suitable, for example, for treating a vein. The inner or outer diameter of a stent, stent graft, or portion of a stent, taking into account, for example, the thickness of the filaments or struts, can be about 6 mm to about 25 mm, about 6 mm to about 20 mm, about 6 mm to about 15 mm, about 6 mm to about 12 mm, about 6 mm to about 9 mm, about 9 mm to about 25 mm, about 9 mm to about 20 mm, about 9 mm to about 15 mm, about 9 mm to about 12 mm, about 12 mm to about 25 mm, about 12 mm to about 20 mm, about 12 mm to about 15 mm, about 15 mm to about 25 mm, about 15 mm to about 20 mm, or about 20 mm to about 25 mm. Some such diameters may be suitable, for example, for treating peripheral blood vessels.The inner or outer diameter of a stent, stent-graft, or portion of a stent, taking into account, for example, the thickness of the filaments or struts, can be about 20 mm to about 50 mm, about 20 mm to about 40 mm, about 20 mm to about 35 mm, about 20 mm to about 30 mm, about 30 mm to about 50 mm, about 30 mm to about 40 mm, about 30 mm to about 35 mm, about 35 mm to about 50 mm, about 35 mm to about 40 mm, or about 40 mm to about 50 mm. Some such diameters may be suitable for treating, for example, the aorta. Other diameters, including diameters larger or smaller than the specified diameters, are also contemplated. The diameter of the device may refer to the diameter of the first end portion, the second end portion, or the intermediate portion, each of which may be in the expanded or unexpanded configuration. The diameter of the device may refer to the average diameter of the device when all portions of the device are in the expanded or unexpanded configuration.

[0212] The length of the stent, stent graft, or first end portion, second end portion, intermediate portion, or sub-portion of the stent may be from about 5 mm to about 150 mm, from about 5 mm to about 110 mm, from about 5 mm to about 70 mm, from about 5 mm to about 50 mm, from about 5 mm to about 25 mm, from about 5 mm to about 20 mm, from about 5 mm to about 10 mm, from about 10 mm to about 150 mm, from about 10 mm to about 110 mm, from about 10 mm to about 70 mm, from about 10 mm to about 50 mm, from about 10 mm to about 25 mm, from about 10 mm to about 2 The length may be about 0 mm, about 20 mm to about 150 mm, about 20 mm to about 110 mm, about 20 mm to about 70 mm, about 20 mm to about 50 mm, about 20 mm to about 25 mm, about 25 mm to about 150 mm, about 25 mm to about 110 mm, about 25 mm to about 70 mm, about 25 mm to about 50 mm, about 50 mm to about 150 mm, about 50 mm to about 110 mm, about 50 mm to about 70 mm, about 70 mm to about 150 mm, about 70 mm to about 110 mm, or about 110 mm to about 150 mm. Other lengths, including lengths longer or shorter than those specified, are also contemplated.

[0213] The porosity of a stent, stent graft, or first end portion, second end portion, intermediate portion, or sub-portion of a stent can be about 5% to about 95%, about 5% to about 50%, about 5% to about 25%, about 5% to about 10%, about 10% to about 50%, about 10% to about 25%, about 25% to about 50%, about 50% to about 95%, about 50% to about 75%, about 50% to about 60%, about 60% to about 95%, about 75% to about 90%, about 60% to about 75%, and combinations thereof. The density of the stent can be inversely proportional to the porosity of the stent. The porosity of a portion of the stent covered by a graft can be about 0%. The porosity can be varied depending on the purpose of certain portions of the stent. For example, the middle section may have a low porosity to increase fluid flow through the device, while the end sections may have a lower porosity to increase flexibility and wall apposition.

[0214] 25A is a schematic side elevational view of yet another exemplary embodiment of a prosthesis 500. The prosthesis or stent or device 500 comprises and / or consists essentially of a plurality of filaments 502 woven together in a woven structure. The stent 500 may be free of graft material, as will be described in more detail below.

[0215] The filaments 502, which may also be described as wires, ribbons, strands, etc., can be woven, braided, layered, or otherwise configured in a cross-sectional manner. The filaments 502 are generally elongated and have a cross-section that is circular, oval, square, rectangular, etc. An exemplary nonwoven filament can have a first layer of filaments wound in a first direction and a second layer of filaments wound in a second direction, with at least some of the filament ends joined together (e.g., by bonding to an expandable ring). Exemplary weave patterns include one above one (e.g., as shown in FIG. 25A ), two above one, two above two, and / or combinations thereof, although other weave patterns are also possible. At the intersections of the filaments 502, the filaments 502 can be spirally wound, can intersect in a sliding relationship, and / or combinations thereof. The filaments 502 can be loose (e.g., held together by weaving), and / or can include joining elements such as welds, sleeves, etc., and / or combinations thereof. The ends of the filament 502 can be cambered, crimped into a ring (e.g., end crimped with a radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc., which can also act as radiopaque markers), twisted, ball welded, bonded, combinations thereof, etc. The woven ends can include ends of the filaments 502 and / or cambered filaments 502, and can have open cells, secured or unsecured filaments 502, welds, adhesives or other fusing means, radiopaque markers, combinations thereof, etc.

[0216] The stent 500 has pores 504 or open, uncovered areas between the filaments 502. The porosity of the stent 500 can be calculated as the external surface area of ​​the pores 504 divided by the total external surface area of ​​the stent 500. The 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 the filaments 502, and combinations thereof.

[0217] The porosity of the stent 500 may be less than about 50% (e.g., slightly more covered area than open area), about 0% (e.g., almost no open area) to about 50%, about 0% to about 45%, about 0% to about 40%, about 0% to about 35%, about 0% to about 30%, about 0% to about 25%, about 0% to about 20%, about 0% to about 15%, about 0% to about 10%, about 0% to about 15%. up to about 5%, about 5% to about 50%, about 5% to about 45%, about 5% to about 40%, about 5% to about 35%, about 5% to about 30%, about 5% to about 25%, about 5% to about 20%, about 5% to about 15%, about 5% to about 10%, about 10% to about 50%, about 10% to about 45%, about 10% to about 40%, about 10% to about 35%, about 10% to about 30%, about 10% to about 25% , about 10% to about 20%, about 10% to about 15%, about 15% to about 50%, about 15% to about 45%, about 15% to about 40%, about 15% to about 35%, about 15% to about 25%, about 15% to about 20%, about 20% to about 50%, about 20% to about 45%, about 20% to about 40%, about 20% to about 35%, about 20% to about 25%, about 25% to about 50%, about 25 % to about 45%, about 25% to about 40%, about 25% to about 35%, about 30% to about 50%, about 30% to about 45%, about 30% to about 40%, about 30% to about 35%, about 35% to about 50%, about 35% to about 45%, about 35% to about 40%, about 40% to about 50%, about 40% to about 45%, about 45% to about 50%, and combinations thereof.

[0218] In some embodiments, porosity less than about 50% can prevent blood from perfusing through the sidewall of stent 500 under normal vascular pressures (e.g., pressure loss across the vessel, pressure loss from afferent to efferent). In certain such embodiments, blood entering the proximal end of stent 500 can be directed to the distal end of stent 500 through the lumen of stent 500 without graft material (e.g., substantially without, without, or substantially without) graft material, yet still without blood loss or substantial blood loss through the sidewall of stent 500. In contrast, in certain so-called "flow diverting stents," porosity is specifically designed to be greater than about 50% to ensure perfusion to the efferent duct.

[0219] The density of the stent 500 can be inversely proportional to the porosity (e.g., the external surface area of ​​the filaments 502 divided by the total external surface area of ​​the stent 500). The density of the stent 500 can be 100% minus the porosity value given above.

[0220] The filaments 502 are at a braid angle 506 relative to an axis perpendicular to the longitudinal axis of the stent 500 (e.g., as shown by an exemplary dashed line in FIG. 25A ). The braid angle 506 can range from just greater than 90 degrees to just less than 180 degrees. The braid angle 506 can be acute or obtuse. In some embodiments, the braid angle 506 is between about 90 degrees and about 180 degrees, between about 120 degrees and about 180 degrees, between about 150 degrees and about 180 degrees, between about 160 degrees and about 180 degrees, between about 170 degrees and about 180 degrees, between about 160 degrees and about 170 degrees, between about 165 degrees and about 175 degrees, combinations thereof, and the like. In some embodiments, the closer the braid angle 506 is to 180 degrees, the greater the radial strength of the stent 500. A device 500 with greater radial strength can assist in opening or maintaining a stoma (e.g., formed as described herein) Other factors, such as the diameter of the filaments 502, the material of the filaments 502, the number of filaments 502, etc., can also affect radial strength.

[0221] All of the filaments 502 may be the same, or some filaments 502 may have different parameters (e.g., material, dimensions, combinations thereof, etc.). In some embodiments, some filaments 502 include a shape memory material (e.g., including Nitinol) and other filaments 502 include a different material (e.g., including aramid fibers (e.g., Kevlar®), Dacron®, biocompatible polymers, etc.). The shape memory material can provide the mechanical structure, while the other material can provide low porosity (e.g., by having thicker sidewall dimensions).

[0222] FIG. 25B is a schematic side elevational view of yet another exemplary 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 in a first weave structure and a second plurality of filaments 524 woven together in a second weave structure. The stent 520 may be free of graft material, as described in more detail herein. The first plurality of filaments 522 may be similar to the filaments 502 of the stent 500 described with respect to FIG. 25A. In some embodiments, the filaments 522 may not have sufficient radial strength to hold a fistula open and / or appose the sidewalls of an artery and / or vein. In certain such embodiments, the filaments 524 may function as an auxiliary support structure to provide radial force. Filaments 524 can be radially outward of filaments 522 (e.g., as shown in FIG. 25B ), radially inward of filaments 522, and / or integral to filaments 522 (e.g., so that the first and second woven structures are not easily separable). Filaments 524 can be the same or a different material as filaments 522, the same or a different thickness as filaments 522, etc., and / or filaments 524 can be braided with the same parameters as filaments 522 or with different parameters (e.g., braid angle) so that filaments 524 achieve greater radial force. Filaments 524 can be joined to filaments 522 (e.g., into a single deployable stent 520) or deployed separately. For example, if filaments 522 are deployed after filaments 524, filaments 524 can hold the stoma open and allow filaments 522 to expand substantially unopposed within the lumen formed by filaments 524. In another example, if filament 524 is deployed after filament 522 is deployed, filament 524 can act as an expansion force on the portion of filament 522 where expansion force is required.

[0223] Although shown in Figure 25B as including a second woven structure, the auxiliary support structure may additionally or alternatively include a helical coil, cut hypotubes, combinations thereof, etc. The determination of the porosity of the prosthesis 520 may be based primarily on the porosity of the first woven structure, such that the auxiliary support structure may be designed to primarily provide radial force (e.g., sufficient force to open or maintain a stoma).

[0224] Although shown as uniform or substantially uniform along the length of stent 500, parameters of stent 500 and filament 502 may vary along stent 500, as described, for example, 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 particular properties and / or functions along various lengths, and / or may have other advantages.

[0225] FIG. 25C is a schematic side elevational view of yet another exemplary embodiment of a prosthesis 540. The prosthesis, stent, or device 540 comprises and / or consists essentially of a plurality of filaments 542 woven together in a woven structure. The stent 540 may be free of graft material, as described in further detail herein. The stent 540 has a first longitudinal section, segment, or portion 544 and a second longitudinal section, segment, or portion 546. For example, parameters such as porosity (e.g., as shown in FIG. 25B ), braid angle, braid type, parameters of the filaments 542 (e.g., diameter, material, etc.), presence of secondary support structures (e.g., secondary support structures), stent diameter, stent shape (e.g., cylindrical, frustoconical), or combinations thereof, may differ between the first longitudinal section 544 and the second longitudinal section 546. The porosity may vary depending on the purpose of a particular portion of the stent 540. For example, the first longitudinal section 544 may be configured for placement in arteries and fistulas and may have a low porosity (e.g., less than about 50%, as described with respect to the stent 500 of FIG. 25A) to enhance fluid flow through the stent 500, while the second longitudinal section may be configured for placement in veins and may have a higher porosity to enhance flexibility and wall apposition.

[0226] In some embodiments, a stent has a first longitudinal section comprising and / or consisting essentially of a low-porosity woven structure configured to divert blood flow from an artery to a fistula without an additional support structure, a second longitudinal section comprising and / or consisting essentially of a low-porosity woven structure configured to divert blood flow through a fistula with an additional support structure configured to hold the fistula open, and a third longitudinal section comprising and / or consisting essentially of a low-porosity woven structure configured to divert blood flow from the fistula to a vein. In certain such embodiments, the first longitudinal section can be configured as stent 500 of FIG. 25A, and the third longitudinal section can be configured as stent 500 of FIG. 25A or as stent 540 of FIG. 25C.

[0227] The difference between the first longitudinal section 544 and the second longitudinal section 546 can be imparted during manufacturing (e.g., by braiding parameters, shape setting, etc.) and / or in situ (e.g., during and / or after deployment (e.g., by stent packing)).

[0228] For example, other variations between the first longitudinal section 544 and the second longitudinal section 546 described herein are also contemplated (e.g., including laser cuts, additional longitudinal sections, etc.). In some embodiments, the stent has a first longitudinal section comprising and / or consisting essentially of a low-porosity woven structure configured to divert flow from an artery to a fistula, a second longitudinal section comprising and / or consisting essentially of low-porosity laser cuts configured to be positioned at the fistula and to divert blood through the fistula and / or to keep the fistula open, and a third longitudinal section comprising and / or consisting essentially of a low-porosity woven structure configured to divert flow from the fistula to a vein. In certain such embodiments, the first longitudinal section can be configured as stent 500 of FIG. 25A, and the third longitudinal section can be configured as stent 500 of FIG. 25A or as stent 540 of FIG. 25C.

[0229] FIG. 27 schematically illustrates an exemplary embodiment of a prosthesis 720, which is described in further detail below with respect to the anatomy of FIG. 27. The prosthesis 720 has a first longitudinal section 722, a second longitudinal section 724, and a third longitudinal section 726 between the first longitudinal section 722 and the second longitudinal section 724. The porosity of the prosthesis 720, even when substantially devoid of graft material, can allow fluid to flow substantially through the lumen of the prosthesis 720 without substantially perfusing through the sidewalls, for example, due to a low-porosity woven structure.

[0230] In embodiments in which the prosthesis 720 is used in the peripheral vasculature, the first longitudinal section 722 can be described as an arterial section, the second longitudinal section 724 can be described as a venous section, and the third longitudinal section 726 can be described as a transition section. The first longitudinal section 722 is configured to appose the sidewall of the artery 700 or another cavity. For example, for some peripheral arteries, the first longitudinal section 722 can have an expanded diameter of about 2 mm to about 4 mm (e.g., about 3 mm). The second longitudinal section 724 is configured to appose the sidewall of the vein 702 or another cavity. For example, for some peripheral veins, the second longitudinal section 724 can have an expanded diameter of about 5 mm to about 7 mm (e.g., about 6 mm). In some embodiments, the second longitudinal section 724 and the third longitudinal section 726 may have a shape that includes a frustoconical shape tapering from the smaller diameter of the first longitudinal section 722 to the larger diameter, rather than being substantially cylindrical as shown in FIG.

[0231] The length of the prosthesis 720 can be configured or sized to place the prosthesis 720 within the artery 700 and / or vein 702 and span the interstitial tissue T between the artery 700 and the vein 702 (e.g., sufficiently to inhibit or prevent longitudinal migration or dislocation of the prosthesis 720). For example, for some peripheral arteries, the length of the first longitudinal section 722 in the expanded or deployed state can be about 20 mm to about 40 mm (e.g., about 30 mm). In another example, for some peripheral veins, the length of the second longitudinal section 724 in the expanded or deployed state can be about 10 mm to about 30 mm (e.g., about 20 mm). In yet another example, for some peripheral vasculature, the length of the third longitudinal section 726 in the expanded or deployed state can be about 5 mm to about 15 mm (e.g., about 10 mm). The overall length of the prosthesis 720 in the expanded or deployed state can be about 30 mm to about 100 mm, about 45 mm to about 75 mm (e.g., about 60 mm). The thickness of the interstitial tissue T is shown as about 2 mm, although other dimensions are contemplated depending on the particular anatomical structure of the deployment location. For example, other dimensions of the prosthesis 720, first longitudinal section 722, and / or second longitudinal section 724 described herein are also contemplated.

[0232] The third longitudinal section 726 has a frustoconical or tapered shape that expands from the smaller diameter of the first longitudinal section 722 to the second longitudinal section 724. The transition points between the longitudinal sections 722, 724, 726 may be distinct or indistinct. For example, the transition section may be described as including a portion of the first longitudinal section 722 and the third longitudinal section 726, or the third longitudinal section 726 may be described as including a cylindrical portion having the same diameter as the first longitudinal section 722. The longitudinal sections 722, 724, 726 may differ in shape and dimensions from those described above and / or may differ in other respects (e.g., material, pattern, etc.). For example, one or more portions may be cylindrical, frustoconical, etc., as shown in FIGS. 12, 13, and 27 and described herein.

[0233] The first longitudinal section 722 and / or the third longitudinal section 726 can have a relatively high radial force, e.g., a force configured to keep a fistula open, and the second longitudinal section 724 can have a relatively low radial force. In some embodiments, the first longitudinal section 722 and / or the third longitudinal section 726 comprise a balloon-expandable stent, a woven stent with a high braid angle, or the like. In some embodiments, the second longitudinal section 724 comprises a self-expanding stent, a woven stent with a low braid angle, or the like. Combinations of laser-cut stents, woven stents, different cut patterns, different weave patterns, and the like are described in more detail herein. In some embodiments, the longitudinal sections 722, 724, 726 can be unitary or separate. The second longitudinal section 724 can be relatively flexible, for example, with a relatively low radial force, which can help the second longitudinal section 724 flex with the anatomical structure during a blood flow pulse.

[0234] In some embodiments, the second longitudinal section 724 and / or the third longitudinal section 726 can comprise a graft material (including, for example, silicone). The graft material can block or prevent flow through the sidewall of the prosthesis 720 and / or can be used to carry drugs. For example, the graft material may or may not occlude or substantially occlude the pores of portions of the prosthesis 720, depending on the purpose of the graft material.

[0235] The proximal and / or distal ends of the prosthesis 720 can be made atraumatic by, for example, having end treatments, a low braid angle, a small filament diameter, combinations thereof, and the like.

[0236] The radial strength or compressive resistance of a stent, stent graft, or a first end portion, second end portion, intermediate portion, or sub-portion of a stent can be about 0.1 N / mm to about 0.5 N / mm, about 0.2 N / mm to about 0.5 N / mm, about 0.3 N / mm to about 0.5 N / mm, about 0.1 N / mm to about 0.3 N / mm, about 0.1 N / mm to about 0.2 N / mm, about 0.2 N / mm to about 0.5 N / mm, about 0.2 N / mm to about 0.3 N / mm, or about 0.3 N / mm to about 0.5 N / mm.

[0237] The values ​​of some parameters of a stent, stent-graft, or first end portion, second end portion, intermediate portion, or sub-portion of a stent can be related (e.g., proportional). For example, the ratio of strut or filament thickness to the diameter of the device portion containing the struts or filaments can be about 1:10 to about 1:250, about 1:25 to about 1:175, or about 1:50 to about 1:100. In other examples, the ratio of device or device portion length to device or device portion diameter can be about 1:1 to about 50:1, about 5:1 to about 25:1, or about 10:1 to about 20:1.

[0238] Portions of a device can include a radiopaque material. For example, the filaments and / or struts of a stent, stent-graft, or first end portion, second end portion, intermediate portion, or sub-portion of a stent can include (e.g., be at least partially made of) titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, combinations thereof, or the like. As another example, the filaments and / or struts of a stent, stent-graft, or portion of a stent can include (e.g., be at least partially made of) a material having a density greater than about 9 grams per cubic centimeter. Separate radiopaque markers can be attached to portions of a device. For example, radiopaque markers can be applied to the proximal end of a device or device portion (e.g., proximal portion of an intermediate portion, proximal portion of a distal portion), the distal end of a device or device portion (e.g., distal portion of an intermediate portion, distal portion of a proximal portion), and / or other portions of a device or device portion. Radiopaque markers between the ends of the device can be useful, for example, to distinguish transitions between materials, sections, etc. Radiopacity can vary along the length of the device. For example, the proximal section can have a first radiopacity (e.g., due to the distal section material and / or a separate marker), and the distal section can have a second radiopacity (e.g., due to the distal section material and / or a separate marker) that is different from the first radiopacity. An expandable member, such as a balloon, can be filled with a radiopaque fluid. An expandable member, such as a balloon, can include radiopaque markers bonded to and / or integrated therewith (e.g., on the outer surface of the expandable member).

[0239] In some embodiments, the device comprises a polymer tube and no support structure is provided, and the middle portion of such a device can be made relatively more flexible than the end portions, for example, by reducing the wall thickness of the polymer tube within the middle portion.

[0240] When a mesh or other support structure is provided in combination with a polymeric tube, the support structure can be positioned around the outside of the tube, positioned within the lumen of the tube, or embedded within the wall of the tube. Two or more support structures can be provided, where each support structure may be in a different position relative to the tube.

[0241] One or both of the end portions of the device can have retention elements, such as hooks, protrusions, or barbs, configured to capture or grasp the inner wall of a blood vessel. The radial force of the end portions after expansion can be sufficient to capture or grasp the inner wall of a blood vessel without the use of retention elements.

[0242] There need not be a well-defined transition between the middle and end portions: for example, the mesh type, material, wall thickness, flexibility, etc. may vary gradually from the end portion to the middle portion, or from the middle portion to the end portion.

[0243] The flexibility of the device may gradually increase moving from the end portions toward the middle portion, as described for devices 134, 140, for example. The change in flexibility may be due to changes in mesh density (e.g., winding density, fenestration size), tube thickness, or other factors. The flexibility of the device may be uniform or substantially uniform throughout the entire length of the support structure (e.g., a stent), or over several portions of the support structure (e.g., over the entire end portion, over the entire middle portion, over one end portion and the middle portion but not the other end portion, etc.).

[0244] The devices described herein may be particularly suited for use as transvascular shunts in percutaneous procedures and may be used in many other medical applications. For example, the devices may be used in angioplasty procedures to treat blocked blood vessels with tortuous or twisted paths, or when the blood vessel may bend or deform at or near the location of the stent. Stents may also be used to repair damaged blood vessels, for example, in aortic graft procedures or after perforation during percutaneous procedures. In some such cases, a midsection of the device may allow the device to conform to the shape of the blood vessel and deform in response to the vessel's movements, while remaining fixed or anchored in place by the end sections, reducing the risk of fatigue failure. In another example, the device may be used to form a shunt between a healthy artery and a healthy vein for dialysis access and / or access for drug administration (e.g., intermittent injections of cancer treatments, which may damage blood vessels).

[0245] 4 and 7, blocking material 251 can be used to help block or prevent backflow of arterial blood. As described in more detail herein, additional or other methods and systems can be used to block or prevent backflow of arterial blood, or, stated differently, to block or prevent arterial blood flow entering a vein from flowing in the normal pre-treatment direction of blood flow in the vein, thereby bypassing oxygenated blood to downstream tissue, such as the leg.

[0246] Without treatment, peripheral vascular disease (PVD) can progress to critical limb ischemia (CLI), which is characterized by severe chronic pain and extensive tissue loss that limits revascularization options and often leads to amputation. CLI has an estimated incidence of approximately 50-100 cases per 100,000 per year and is associated with a mortality rate of as much as 20% within 6 months of onset.

[0247] Interventional radiologists have actively attempted to treat CLI by attempting to completely open a chronic total occlusion (CTO) or by bypassing the CTO into the subintimal space using products such as the Medtronic Pioneer catheter, which attempts to thread a wire into the subintimal space proximal to the CTO and then re-enter the vessel distal to the occlusion. Once the wire is in place, the user can optionally place a stent to create a wider channel and then provide a bypass conduit through the occlusion. Traditional approaches such as percutaneous transluminal angioplasty (PTA), stenting, and drug-eluting balloons (DEBs) for treating PAD can additionally or alternatively be used to treat CLI if a wire can cross the occlusion.

[0248] According to the amputee-calition.org website, some statistics on the issue of CLT are as follows: There are nearly 2 million limb amputees in the United States. Among those with limb loss, the main causes are: vascular disease (54%) (diabetes and peripheral arterial disease (PAD)); trauma (45%), and Cancer (less than 2%). Approximately 185,000 amputations are performed in the United States each year. Hospital costs associated with amputations totaled more than $6.5 billion in 2007. Survival rates after amputation vary based on a variety of factors. Those undergoing amputation due to vascular disease (including PAD and diabetes) have a reported 30-day mortality rate of 9%-15%, with long-term survival rates of 60% at 1 year, 42% at 3 years, and 35%-45% at 5 years. Nearly half of those who lose a limb to dysvascular disease die within five years, a higher five-year mortality rate than those who suffer from colorectal, breast, and prostate cancer. Up to 55% of people with diabetes who have had a lower limb amputation will need another leg amputated within two to three years.

[0249] CLI has been treated surgically by open venous arterialization since the early 1900s. A small series of clinical trials using open surgical approaches, such as those outlined in a 2006 meta-analysis by Lu et al. entitled "Meta-analysis of the clinical effectiveness of venous arterialization for salvage of critically ischemiclimbs" (European Journal of Vascular and Endovascular Surgery, vol. 31, pp. 493-499), have been published over the years. The paper reached the following results and conclusions: result: A total of 56 studies were selected for comprehensive review. No randomized controlled trials (RCTs) were identified. Seven patient groups, including 228 patients, met the inclusion criteria. Overall limb salvage at 1 year was 71% (95% CI: 64% to 77%), and the 1-year secondary patency rate was 46% (95% CI: 39% to 53%). The majority of patients who avoided major amputation had successful wound healing, did not experience rest pain, and were free of serious complications. Conclusion: Based on limited evidence, venous arterialization can be considered a viable alternative before major amputation in patients with “inoperable” chronic critical limb ischemia.

[0250] Among other conditions described herein, the methods and systems described herein can create an arterial-venous (AV) fistula within the below-the-knee (BKT) vasculature using an endovascular, minimally invasive approach. Such methods may be appropriate for patients who (i) have a clinical diagnosis of symptomatic critical limb ischemia as defined by Rutherford 5 or 6 (critical ischemic ulcer or frank gangrene), (ii) are evaluated by a vascular surgeon and interventionist and determined not to be amenable to surgical or endovascular treatment, and / or (iii) have a clear preference for major amputation.

[0251] 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 launching catheter with a needle, etc.), a second ultrasound catheter (e.g., a venous catheter, a targeting catheter, etc.), and a prosthesis (e.g., a covered nitinol stent graft in a delivery system (e.g., a 7 Fr (approximately 2.3 mm) 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 the ultrasound catheter(s). The catheters and prostheses described above can be used in the system or kit, and other, additional, and / or modified possible components are described in detail below.

[0252] FIG. 14A is a schematic side cross-sectional view of an exemplary embodiment of an ultrasound-emitting catheter 170 (e.g., a first ultrasound catheter, an arterial catheter (e.g., for extending the needle from an artery into a vein), or a venous catheter (e.g., for extending the needle from a vein into an artery)) having a needle 172. The catheter 170 is placed in an artery with the needle 172 in a retracted position within the lumen of the catheter 170. The catheter 170 can be tracked over a guidewire (e.g., a 0.014 inch (approximately 0.36 mm) guidewire) and / or placed through a sheath within the artery (e.g., the femoral artery) and advanced to the point of total occlusion in the artery (e.g., in the tibial artery). The catheter 170 has a handle 174 with a pusher ring 176. Longitudinal or distal advancement of the pusher ring 176 can advance the needle 172 from the lumen of the catheter 170 out of the artery and into the vein, as described herein. Other mechanisms for advancing needle 172 are contemplated (e.g., rotary, motorized, etc.). A guidewire (e.g., a 0.014 inch (approximately 0.36 mm) guidewire) can be placed through needle 172 (e.g., as described with respect to guidewire 14 of FIG. 3) before, after, and / or during needle advancement; this guidewire can be referred to as a crossover wire.

[0253] Figure 14B is an enlarged, schematic, side cross-sectional view of the distal portion of ultrasound-emitting catheter 170 within circle 14B in Figure 14A. As needle 172 is advanced or launched, it extends radially outward from lumen 173 of catheter 170. In some embodiments, lumen 173 terminates proximate ultrasound transmitting device 178. Needle 172 can extend along a path that aligns with (e.g., parallel to) the path of the directional ultrasound signal transmitted by ultrasound transmitting device 178. Figure 14B also shows lumen 175, which can be used to house a guidewire that tracks catheter 170 to a desired location.

[0254] FIG. 15A is a schematic side view of an exemplary embodiment of an ultrasound targeted catheter 180 (e.g., a second ultrasound catheter, an arterial catheter (e.g., for extending a needle from a vein into an artery), or a venous catheter (e.g., for extending a needle from an artery into a vein)). FIG. 15B is an enlarged, schematic, side cross-sectional view of the ultrasound targeted catheter 180 within circle 15B of FIG. 15A. FIG. 15C is an enlarged, schematic, side cross-sectional view of the ultrasound targeted catheter 180 within circle 15C of FIG. 15A. The catheter 180 can be tracked 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., the femoral vein) and advanced to a point proximal to and / or parallel to the distal end of the catheter 170 (e.g., in the tibial artery) and / or to an occlusion in the artery. The catheter 180 has an ultrasound receiving transducer 182 (e.g., an omnidirectional ultrasound receiving transducer) that can act as a target in the vein to align the needle 172 of the catheter 170. The catheter 180 can be left in place, or can remain stationary or substantially stationary while the catheter 170 is rotated and moved longitudinally to obtain a good or optimal ultrasound signal that indicates that the needle 172 is aligned with the catheter 180.

[0255] The catheters 170, 180 may be connected to ultrasound transmitters and receivers that are connected to and controlled by computer-implemented transmitter and receiver software. As described in further detail herein, the catheter 170 has a flat or directional ultrasound transmitter 178 configured to transmit ultrasound signals having a small angular spread or tight beam (e.g., small beam width) in the direction of the path of the needle 172 upon advancement from the lumen 173 of the catheter 170. The catheter 180 has an omnidirectional (360-degree) ultrasound receiver 182 configured to act as a target for the ultrasound signals transmitted by the directional transmitter 178 of the catheter 170. Upon extending the needle 172 (e.g., by advancing the ring 176 of the handle 174 longitudinally), the catheter 170 is rotated until a peak ultrasound signal is displayed indicating that the needle 172 is aligned with the catheter 180 so that the needle 172 can advance out of the artery in which the catheter 170 resides, through the interstitial tissue, and into the vein in which the catheter 180 resides.

[0256] FIG. 16 is an exemplary embodiment of a graph for detecting catheter alignment as may be displayed on an ultrasound system display device (e.g., a laptop, tablet computer, smartphone, combinations thereof, etc.). The graph in FIG. 16 shows a signal emanating from a transmitting catheter in a vein being received by a receiving catheter in a vein. The second frequency envelope on the right is the received signal. The distance from the left side of the illustrated screen to the leading edge of the second frequency envelope may indicate the distance between the catheters. The operator may, for example, move the catheter within the artery both rotationally and longitudinally until the second envelope is maximized, indicating that the catheter is correctly oriented.

[0257] FIG. 17 is a schematic side elevation view of an exemplary embodiment of a prosthesis (e.g., stent, stent-graft) delivery system 190. In some embodiments, delivery system 190 is a 7 Fr (approximately 2.3 mm) delivery system. FIG. 18 is a schematic side elevation view of an exemplary embodiment of a prosthesis (e.g., stent, stent-graft) 200. In FIG. 17, a prosthesis (e.g., prosthesis 200, other prostheses described herein, etc.) is in a compressed or crimped state adjacent a distal end 192 of delivery system 190. In some embodiments, prosthesis 200 comprises a shape-memory stent covered by a graft material, e.g., as described above. Once the cross wires extend from the artery into the vein, delivery system 190 can be advanced over the cross wires, e.g., as a result of being advanced through needle 172, as described herein. The prosthesis 200 can be deployed from the delivery system 190 by, for example, squeezing a trigger handle 194 of the delivery system 190 to retract the prosthesis 200 proximally and / or advance it distally through an outer covering sheath. The prosthesis 200 can create a flow path between an artery and a vein through interstitial tissue. Other types of delivery systems and prostheses are also contemplated.

[0258] Referring again to FIG. 17 , some non-limiting exemplary dimensions of the delivery system 190 are provided. The travel distance 196 of the trigger handle 194 can be, for example, from about 0.4 inches (approximately 1 cm) to about 12 inches (approximately 30 cm), from about 1 inch (approximately 2.5 cm) to about 8 inches (approximately 20 mm), or from about 2 inches (approximately 5 cm) to about 6 inches (approximately 15 mm) (e.g., about 2 inches (approximately 5 cm)). In some embodiments, the travel distance 196 of the trigger handle 194 is at least as long as the length of the prosthesis 200 to be deployed (e.g., in a radially expanded state). In some embodiments, a gearing or other mechanism can be used to shorten the travel distance 196 of the trigger handle 194 to less than the length of the prosthesis 200 to be deployed (e.g., in a radially expanded state). Distance 196 can be adjusted based on, for example, at least one of the length of deployed prosthesis 200, the degree to which deployed prosthesis 200 is retracted, the deployment mechanism (e.g., whether the outer sheath is retracted proximally, the prosthesis 200 is pushed distally forward, or both, whether delivery system 190 includes a transmission, etc.), combinations thereof, etc. The length 197 of the outer sheath or catheter portion can be, for example, about 40 inches (approximately 1020 mm) to about 50 inches (approximately 1270 mm), about 46 inches (approximately 1170 mm) to about 47 inches (approximately 1190 mm), or about 46.48 inches (approximately 1180 mm) to about 46.7 inches (approximately 1186 mm). The overall length 198 of delivery system 190 from the proximal tip to the distal tip can be, for example, about 40 inches (approximately 1000 mm) to about 60 inches (approximately 1500 mm). Lengths 197, 198 can be adjusted based on, for example, at least one of the length of deployed prosthesis 200, the degree to which deployed prosthesis 200 is to be retracted, the height of the patient, the location of the occlusion being treated, combinations thereof, etc. In some embodiments, it may be advantageous to space trigger handle 194 from the vascular access point, for example, by about 10 cm to about 30 cm (e.g., at least about 20 cm), to allow for easier handling or management by a user.In some such embodiments, length 197 may be about 120 cm to about 130 cm (eg, for an antegrade approach) or about 150 cm to about 180 cm (eg, for a contralateral approach).

[0259] Referring again to FIG. 18, some non-limiting exemplary dimensions of the prosthesis 200 are provided, depending on the circumstances, at least in the compressed state. The thickness 201 of the structural struts can be, for example, about 0.05 mm to about 0.5 mm, or about 0.1 mm to about 0.2 mm (e.g., about 0.143 mm). The inter-strut spacing 202 of the structural struts can be, for example, about 0.005 mm to about 0.05 mm, or about 0.01 mm to about 0.03 mm (e.g., about 0.025 mm). The thickness 203 of the connecting struts can be, for example, about 0.05 mm to about 0.5 mm, or about 0.1 mm to about 0.2 mm (e.g., about 0.133 mm). The longitudinal length 204 of the structural components can be, for example, about 1 mm to about 5 mm, or about 2.5 mm to about 3 mm (e.g., about 2.8 mm). The longitudinal length 205 between structural components can be, for example, about 0.25 mm to about 1 mm, or about 0.5 mm to about 0.6 mm (e.g., about 0.565 mm). The length 206 of the strut within the structural component, including all portions that wrap around and around, can be, for example, about 25 mm to about 100 mm, or about 65 mm to about 70 mm (e.g., about 67.62 mm). The overall longitudinal length of the prosthesis 200 can be, for example, about 25 mm to about 150 mm, or about 50 mm to about 70 mm (e.g., about 62 mm). As described herein, a wide variety of laser-cut stents, woven stents, and combinations thereof, including various sizes, are contemplated. The struts described herein can include wire or filament, or portions not cut from hypotubes or sheets.

[0260] The proximal and / or distal ends of the prosthesis 200 may optionally include a ring 210. The ring 210 can, for example, aid in placement of the prosthesis 200 within an artery and / or vein. The circumferential width 211 of the ring 210 can be, for example, about 0.25 mm to about 1 mm, or about 0.5 mm to about 0.75 mm (e.g., 0.63 mm). The longitudinal length 212 of the ring 210 can be, for example, about 0.25 mm to about 2 mm, or about 0.5 mm to about 1 mm (e.g., 0.785 mm). In some embodiments, the ratio of the overall length of the prosthesis 200 to the longitudinal length 212 of the ring 210 can be about 50:1 to about 100:1 (e.g., about 79:1). The dimensions 211, 212 of the ring 210 can be adjusted based on, for example, at least one of strut thickness, diameter of the prosthesis (eg, relative to the vessel), overall length of the prosthesis, material, shape-setting characteristics, combinations thereof, and the like.

[0261] FIG. 19 is a schematic side elevation view of another exemplary embodiment of a prosthesis 220. The prosthesis 200 can have the shape of the prosthesis 220, for example, in a radially expanded state (e.g., upon deployment from a delivery system 190). FIG. 19 illustrates an exemplary shape of the prosthesis 220 having a first portion 221 and a second portion 225. The first portion 221 has a substantially cylindrical or frustoconical shape with a length 222 of about 15 mm to about 25 mm (e.g., about 21 mm) and a diameter 223 of about 2.5 mm to about 5 mm (e.g., about 3.5 mm). The second portion 225 has a substantially frustoconical or frustoconical shape with a length 226 of about 30 mm to about 50 mm (e.g., about 41 mm) and a widest diameter 227 of about 4 mm to about 10 mm, about 4 mm to about 7 mm (e.g., about 5.5 mm), etc. The taper angle of the second portion 225 away from the first portion 221 can be about 0.02 degrees to about 0.03 degrees (eg, about 0.024 degrees).

[0262] Further details regarding prostheses that can be used in accordance with the methods and systems described herein are provided in U.S. patent application Ser. No. 13 / 791,185, filed March 8, 2013, the entire contents of which are incorporated herein by reference.

[0263] 20A-20H generally illustrate an exemplary embodiment of a method for performing retrograde perfusion. The method is described with respect to the peripheral vasculature, such as the lower extremities, but can be adapted as needed for other body cavities (e.g., the heart, other peripheries, etc.). Some steps, such as anesthesia, incision of specific sites, suturing, etc., can be omitted for clarity. In some embodiments, the method can be performed from a vein to an artery (e.g., via an intravenous catheter, as described below).

[0264] Access to the femoral artery and femoral vein is gained. For example, using the Seldinger technique, an introducer sheath (e.g., a 7 French (approximately 2.3 mm)) is inserted into the femoral artery, and an introducer sheath (e.g., a 6 French (approximately 2 mm)) is inserted into the femoral vein. A guidewire (e.g., a 0.014 inch (approximately 0.36 mm), 0.035 inch (approximately 0.89 mm), or 0.038 inch (approximately 0.97 mm)) is inserted through the introducer sheath in the femoral artery and guided into the distal portion of the affected posterior or anterior tibial artery 300. A second guidewire (e.g., a 0.014 inch (approximately 0.36 mm), 0.035 inch (approximately 0.89 mm), or 0.038 inch (approximately 0.97 mm)) or snare is inserted through the introducer sheath in the femoral artery. In embodiments in which a snare is used, the third guidewire, fourth guidewire, etc. described herein are accurate even if the numbering is not sequential.

[0265] A venous access needle is inserted percutaneously into a target vein, for example, a tibial vein (e.g., the proximal tibial vein (PTV)). In some embodiments, the venous access needle may be ultrasound-guided. In some embodiments, contrast is injected (retrograde) into the saphenous vein on the side of the leg and then flows into the PTV. This flow path can be visualized using fluoroscopy, allowing the venous access needle to be guided by fluoroscopy rather than or in addition to ultrasound.

[0266] The target vein can be accessed proximally and distally (e.g., several inches or centimeters) below where the launch catheter 310 is to be placed. In some embodiments, the target vein can be in the ankle. Once the venous access needle is in the vein, a third guidewire (or a "second" guidewire, if a snare is used instead of a second guidewire) is inserted into the venous access needle and advanced antegrade through the target vein to the femoral vein. This access method can advantageously reduce problems caused by advancing a wire retrograde across a venous valve, as described in more detail below. The third guidewire is snared, for example, using fluoroscopic guidance, and pulled through the femoral venous sheath. The target catheter 320 is inserted into the femoral venous sheath over the snared third guidewire. As shown in FIG. 20A, the target catheter 320 is advanced over the third guidewire into the venous system until the target catheter 320 is adjacent to and / or parallel to the guidewire and / or adjacent to the occlusion 304 in the distal portion of the affected posterior or anterior tibial artery.

[0267] In some embodiments, the third guidewire may have an ultrasound receiving transducer (e.g., omnidirectional) attached to provide a target for the signal transmitted by the launch catheter 310, or the target catheter 320 may be tracked over the third guidewire, either of which may allow for the omission of several techniques (e.g., femoral vein access, introduction of a venous introducer sheath, insertion of a second guidewire, antegrade advancement of the third guidewire into the femoral vein, snaring of the third guidewire, and advancement of the target catheter 320 over the third guidewire).

[0268] In some embodiments, the PTV may be accessed directly using, for example, ultrasound, which may allow the target catheter 320 to be placed directly into the PTV using, for example, a small sheath, which may allow omission of several techniques (e.g., femoral vein access, introduction of a venous introducer sheath, insertion of a second guidewire, and antegrade advancement of a third guidewire up to the femoral vein).

[0269] In some embodiments, catheter 320 is not an over-the-wire catheter, but rather 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 accessing the PTV.

[0270] An ultrasound transducer generally has two electrodes capable of vibrating, with surfaces separated by a ceramic. Incoming or received ultrasound signal waveforms combine into a length-extension mode, as shown in FIG. 21. FIG. 21 is a schematic perspective view of an exemplary embodiment of an ultrasound receiving transducer 350. When the proximal or upper end 352 of the transducer 350 and the distal or lower end 354 of the transducer are conductive and electrically connect to a wire, the transducer can receive ultrasound signals. In some embodiments, the transducer 350 has a length 356 of about 0.1 mm to about 0.4 mm (e.g., about 0.25 mm). In some embodiments, the transducer 350 has an overlap length 358 of about 0.1 mm to about 0.3 mm (e.g., about 0.2 mm). In some embodiments, the transducer 350 has a diameter similar to, substantially similar to, or the same as the guidewire to which the transducer 350 is attached. In some embodiments, an array or series of laminates may enhance the signal reception capabilities of the transducer 350 .

[0271] In some embodiments, a guidewire having an ultrasound receiving transducer can include a piezoelectric film (e.g., including plastic), which can enhance the transducer's signal reception capabilities. FIG. 22 is a schematic cross-sectional view of another exemplary embodiment of an ultrasound receiving transducer 360. The ultrasound receiving transducer 360 shown in FIG. 22 includes an optional lumen 368. The ultrasound receiving transducer 360 includes a series of layers 362, 364, and 366. Layer 362 can include a polymer (e.g., polyvinylidene fluoride (PVDF)) layer. Layer 364 can include an inorganic (e.g., tungsten carbide) layer. Layer 366 can include a polymer (e.g., polyimide) layer. Layer 366 can have a thickness of about 25 micrometers (μm or microns) to about 250 μm (e.g., at least about 50 μm).

[0272] Launching catheter 310 is tracked over a guidewire within the femoral and tibial arteries proximal to and adjacent to occlusion 304, as shown in FIG. 20B. Catheter 310 may be more proximal to occlusion 304, depending on the suitability of the retroperfusion process in that portion of the anatomy. In some embodiments, catheter 310 may be positioned in the distal portion of the posterior or anterior tibial artery, for example, adjacent to catheter 320. In some embodiments, catheter 310 may be positioned within a few inches or centimeters of the ankle.

[0273] The launch catheter 310 transmits a directional ultrasound signal. As indicated by arrows 311, 312 in FIG. 20C, the launch catheter 310 is rotated and moved longitudinally until the signal is received by the target catheter 320. When the signal is received, alignment is indicated, whereby the vein is successfully accessed by extending a needle from the launch catheter 310, and a crossover needle 314 advances from the catheter 310 into the tibial artery 300 and into the tibial vein 302, as shown in FIG. 20D. The accuracy of the placement of the crossover needle 314 to form a fistula between the artery 300 and the vein 302 can be confirmed using, for example, contrast and fluoroscopy.

[0274] In some embodiments, the ultrasound signal can be used to determine the distance between the artery 300 and the vein 302. Referring again to Figure 16, the distance from the left side of the illustrated screen to the leading edge of the second frequency envelope can be used as an indication of the distance between the catheters.

[0275] 16, a display device can graphically show the signal alignment peaks to allow the user to determine the alignment position. In some embodiments, the signal alignment can change color, for example, from red to green, when it exceeds or falls below a threshold. In some embodiments, for example, an audible signal can be sent when the alignment signal exceeds a threshold, thereby allowing the user to maintain focus on the patient rather than nearly continuously monitoring the screen.

[0276] In some embodiments, a horizontal line on the screen can be moved to indicate the maximum signal, or peak, achieved to that point during the procedure. This line can be referred to as a "peak hold." If a greater signal value is achieved, the horizontal line moves to match the higher value. If manipulation cannot raise the peak above the horizontal line, this can indicate maximum alignment. If the signal peak drops below the horizontal line by a certain amount, the catheter has moved and can no longer be properly aligned. Because the alignment level indicated by the horizontal line was previously achieved during the procedure, the user knows that such alignment level can be achieved with further rotational and / or longitudinal manipulation.

[0277] A fourth guidewire 316 (e.g., 0.014 inches (approximately 0.36 mm)) (or a "third" guidewire if a snare is used instead of the second guidewire) is placed through the lumen of the crossing needle 314 of the catheter 310 in a retrograde (of the vein 302) direction on the leg side into the tibial vein 302, as shown in FIG. 20E. Outer cuff pressure can be applied over the needle intersection to reduce flow in the artery 300 to inhibit or prevent hematoma formation and / or to flood the vein to facilitate valve crossing. Leaving the guidewire 316 in place, the catheters 310, 320 can be advanced and extended out of the introducer sheath in the femoral artery, through the arterial tree, and into the tibial vein 302.

[0278] Several techniques for crossing the guidewire 316 from the artery 300 into the vein 302 may be used instead of or in addition to the directional ultrasound techniques described herein.

[0279] In some embodiments, a tourniquet can be applied to the leg, thereby increasing the diameter of the vein. In some embodiments, a blocking material (e.g., a blocking balloon, as described with respect to FIGS. 4 and 7) can be used to increase the diameter of the vein. For example, the vein can be enlarged by restricting venous flow. A larger vein diameter provides a larger target for the crossover needle 314, making the vein 300 more easily accessible by the crossover needle 314.

[0280] In some embodiments, a PTA balloon can be used in the target vein, and a needle catheter (e.g., Outback, available from Cordis) can be targeted to the PTA balloon under fluoroscopy. The crossing needle 314 can puncture the PTA balloon, and a drop in pressure in the PTA balloon can confirm proper alignment of the crossing needle 314. The PTA balloon can increase the diameter of the vein, making the crossing needle 314 a larger target, making the vein 300 more easily accessible by the crossing needle 314. A guidewire 316 can be advanced through the crossing needle 314 to the PTA balloon.

[0281] In some embodiments, the PTA balloon has a mesh (e.g., a woven mesh) embedded within the balloon's polymer. If a balloon without such a mesh is punctured, the balloon material may break and cause embolism (e.g., fragments of the balloon may be swept downstream). The mesh can help limit tearing of the balloon material, thereby inhibiting or preventing the balloon material from causing embolism. In some implementations, a balloon without a mesh can be configured to snare a guidewire upon being collapsed (e.g., by entangling the guidewire infolds of the balloon), whether or not punctured.

[0282] In some embodiments, two PTA balloons spaced longitudinally along the catheter axis can be used within the target vein, and a needle catheter can target one of the PTA balloons. When one of the PTA balloons is punctured by the cross needle 314, the punctured PTA balloon no longer acts as a dam for the contrast agent, allowing the contrast agent in the well between the balloons to be released. The release of contrast agent can be monitored using fluoroscopy. The PTA balloons can be on the same catheter side or on different catheter sides.

[0283] In some embodiments, two PTA balloons spaced longitudinally along the catheter axis can be used within the target vein, and a needle catheter can target the space or well between the PTA balloons. Puncture of the well by the cross needle 314 can disturb the contrast agent within the well. The contrast agent disturbance can be monitored using fluoroscopy. The PTA balloons can be on the same catheter side or on different catheter sides.

[0284] In some embodiments where a PTA balloon may be used in combination with an ultrasound target within a target vein, a PA balloon catheter includes a PTA balloon and an ultrasound receiving transducer (e.g., omnidirectional). In some such embodiments, the launch catheter 310 can target the PTA balloon under fluoroscopy and / or target the ultrasound receiving transducer, as described herein. The crossing needle 314 can puncture the PTA balloon, and a drop in pressure in the PTA balloon can confirm proper alignment of the crossing needle 314. The PTA balloon can increase the diameter of the vein, thereby creating a larger target for the crossing needle 314 and making the vein 300 more accessible by the crossing needle 314. A guidewire 316 can be advanced through the crossing needle 314 to the PTA balloon.

[0285] In some embodiments, a LeMaitre device (e.g., the UnBalloon™ Non-Occlusive Modeling Catheter, available from LeMaitre Vascular, Inc., Burlington, Massachusetts) can be used within the target vein. In some embodiments, the LeMaitre device can increase the diameter of the vein. A larger diameter vein can provide a larger target for the crossing needle 314, making the vein 300 easier to access by the crossing needle 314. In some embodiments, the needle 314 can penetrate the LeMaitre device. In some such embodiments, the LeMaitre device can serve as a mesh target (e.g., comprising a radiopaque material visible under fluoroscopy) for the crossing needle 314. The mesh of the LeMaitre device can be radially expanded by distally advancing a proximal portion of the mesh and / or proximally retracting a distal portion of the mesh (e.g., by squeezing the ends together like an umbrella) and / or by allowing the mesh to self-expand (e.g., in embodiments in which at least a portion of the mesh comprises a shape-memory material). In some embodiments, the LeMaitre device can grip the crossover wire as it closes to hold the crossover wire within the target vein.

[0286] In some embodiments, the launch catheter 310 can include a first magnet having a first polarity, and the target catheter 320 can include a second magnet having a second polarity. When the magnets are close enough to cause a magnetic force to move one or both of the catheters 310, 320, the crossing catheter 314 can be advanced to create a fistula between the artery 300 and the vein 302. In some embodiments, the first magnet can be circumferentially aligned with the crossing needle 314, and / or the launch catheter 310 can be magnetically shielded to provide rotational alignment. In some embodiments, the second magnet can be relatively thin longitudinally to provide longitudinal alignment. In some embodiments, the crossing needle 314 and / or guidewire 316 can be magnetically pulled from the artery 300 to the vein 302, or vice versa. Some systems can have both ultrasound and magnetic guidance. For example, ultrasound guidance can be used for initial alignment, and magnetic guidance can be used for fine alignment.

[0287] 20A-20H , as shown in FIG. 20F , prosthesis delivery system 330 carrying prosthesis 349 is tracked over guidewire 316 through the interstitial space between artery 300 and vein 302. In some embodiments, a separate PTA balloon catheter (e.g., about 2 mm) can be tracked over guidewire 316 to pre-dilate the fistula between artery 300 and vein 302 prior to introducing prosthesis delivery system 330. The use of a PTA balloon catheter can depend, for example, on the radial force of prosthesis 340.

[0288] The prosthesis 340 is deployed from the prosthesis delivery system 330, for example, by manipulating the trigger handle 194 (FIG. 17). In some embodiments, for example, if the prosthesis 340 is unable to expand and / or advance, the prosthesis delivery system 330 can be removed and a PTA catheter (e.g., about 2 mm) can be advanced over the guidewire 316 to attempt to enlarge or further enlarge the fistula between the artery 300 and the vein 302. Deployment of the prosthesis 340 can then be attempted again (e.g., by self-expansion, balloon expansion, etc.). In some embodiments, deployment of the prosthesis 340 can remodel the vessel, expanding the vessel diameter 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 in which prosthesis 340 is self-expanding, the degree of remodeling may vary over time, eg, prosthesis 340 expands when the blood vessel expands and contracts when the blood vessel contracts.

[0289] As shown in FIG. 20G, once the prosthesis 340 is deployed, the fistula can be dilated with a PTA catheter. 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, a combination thereof, etc. In some embodiments, the prosthesis delivery system 330 can comprise a PTA balloon catheter (e.g., proximal or distal to the prosthesis 340) useful for one, more than one, or all of the optional PTA balloon catheterization techniques described herein. In embodiments in which the prosthesis has a conical portion, the PTA balloon can have a conical portion. Once the prosthesis 340 is in place, the prosthesis delivery system 330 can be removed, as shown in FIG. 20H. This creates an AV fistula between the artery 300 and the vein 302. Verification of placement of the venous catheters 310, 320, 330 and prosthesis 340 may be confirmed throughout part or all of the procedure under fluoroscopy using contrast injection.

[0290] In some embodiments, a marker (e.g., a clip, lancet, scissors, pencil, etc.) can be applied to the skin (e.g., glued, placed on, etc.) to generally mark the location of the fistula formed between the artery 300 and the vein 302 by the crossing needle 314 prior to deployment of the prosthesis 340. In embodiments using a blood pressure monitor that the user inflates over the fistula to avoid bleeding, the lack of blood flow can make visualizing or even assessing the fistula site difficult, and the marker can provide such identification. In embodiments in which the transmitting / receiving catheters are removed after fistula formation, the intersection point can be difficult for the user to feel or determine, and the marker can provide such identification. If the fistula is enlarged (e.g., to increase or maximize interstitial space penetration), it may be preferable to be able to align the midpoint of the dilation balloon with the midpoint of the fistula. In some embodiments, the marker can be visible under fluoroscopy (e.g., comprising a radiopaque material) to allow the user to locate and remember the location of the fistula under fluoroscopy before deploying the prosthesis 340.

[0291] Once the prosthesis 340 is in place, the only obstacle to blood flowing through the vein 302 to the foot is the valve within the vein. Maneuvering a guidewire across the venous valve can be difficult because, for example, pressure from the artery may be insufficient to dilate the vein and disable the valve. As described in further detail below, it has been discovered that venous valves distal to the AV fistula can be disabled or disabled using one or more of a variety of techniques, such as a PTA catheter, a stent (e.g., a covered stent, a stent graft, etc.), and a valvulotome. Disabling the venous valve can allow blood to flow distal to the venous circulation of the leg via retrograde perfusion from the femoral artery, retrograde flow within the vein 302, and retrograde flow within the venules and capillaries to supply oxygenated blood to the foot in CLI patients.

[0292] In some embodiments, a high pressure PTA balloon catheter can be used (eg, when inflated to greater than about 10 atm (approximately 1013 kilopascals (kPa))) to render the venous valves non-functional.

[0293] In some embodiments, one or more stents can be placed across one or more venous valves to disable those valves. For example, such a stent should have sufficient radial force to hold the valve open. The stent can forcefully tear the valve. In some embodiments, the stent includes a covering or graft. Certain such embodiments can cover venous collaterals. In some embodiments, the stent is bare, i.e., does not include a covering or graft. Certain such embodiments can reduce cost. The venous stent can extend along a length (e.g., the entire length) of the vein. For example, in some embodiments, the entire length of the PTV is lined with a covered stent that covers venous collaterals and tears venous valves.

[0294] In some embodiments, the venous stent is separate from the fistula prosthesis. A separate venous stent can allow for more flexibility with respect to characteristics such as dimensions (e.g., length, diameter), materials (e.g., with or without a covering or graft), and other properties. FIG. 31A schematically illustrates an exemplary embodiment of a venous stent 342 and an exemplary embodiment of a separate arteriovenous fistula stent 340. The venous stent 342 may be spaced apart from the fistula stent 340 (e.g., as shown in FIG. 31A ), abut the fistula stent 340, or overlap, nest, or be coaxial with the fistula stent 340 (e.g., the distal segment of the fistula stent 340 is at least partially inside the proximal segment of the venous stent 342, or the proximal segment of the venous stent 342 is at least partially inside the distal segment of the fistula stent 340). In embodiments where the fistula stent 340 and the venous stent 342 overlap, the venous stent 342 is first placed so that the proximal end of the venous stent 342, which faces the direction of retrograde blood flow, is covered by the fistula stent 340, reducing or eliminating blood flow disruption 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 venous stent 342 can then be placed over the fistula stent 340 (e.g., by tracking a stent deployment device over the same guidewire) so that both stents 340, 342 can share at least one deployment parameter. The venous stent 342 can be deployed before or after the fistula stent 340. The venous stent 342 can have a length of about 2 cm to about 30 cm (e.g., about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, about 30 cm, ranges between such values, etc.).

[0295] In some embodiments, the venous stent is integrated with the fistula prosthesis. An integrated venous stent can allow for greater flexibility with respect to characteristics such as dimensions (e.g., length, diameter), materials (e.g., with or without a covering or graft), and other properties. FIG. 31B schematically illustrates an exemplary embodiment of an arteriovenous fistula stent 344 with an integrated venous stent. FIG. 31C schematically illustrates an exemplary embodiment of a fistula stent 344 with an integrated venous stent. The stent 344 has a first portion 346 configured for placement within an artery, a second portion 350 configured for placement within and lining a length of a vein, and a third portion 348 longitudinally disposed between the first portion 346 and the second portion 350. In embodiments in which the first portion 346 and the second portion 350 have different diameters (e.g., as shown in FIG. 31C), the third portion 348 can be tapered. In some embodiments, the portion of second section 350 configured to line a vein has different properties (e.g., diameter, material, radial stiffness, combinations thereof, etc.) than other portions of second section 350. The length of second section 350 can be greater than the length of first section 346. For example, second section 350 can have a length configured to line a blood vessel such as the PTV. The second section 350 can have a length of about 2 cm to about 30 cm (e.g., about 2 cm, about 3 cm, about 4 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, about 10 cm, about 11 cm, about 12 cm, about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, about 30 cm, ranges between such values, etc.).

[0296] In some in situ bypass procedures, the saphenous vein is attached to an artery in the upper limb and another artery in the lower limb, bypassing any blockages in the artery. In some such procedures, the vein is peeled from the patient, longitudinally inverted, and left in place so that blood flow is retrograde (across the vein's valves) rather than used as a prosthesis. A standard valvulotome can be placed into the saphenous vein from below, advanced to the apex in a collapsed state, opened, and then pulled back in an open state, cutting the venous valves in the process. The cutting surface of such a valvulotome faces backward to cut when retracted during these procedures. FIG. 23A is a schematic perspective view of an exemplary embodiment of a valvulotome 400 having a proximally facing blade 402 that can be used in conjunction with such procedures.

[0297] In some embodiments of the methods described herein, distal access to the venous valve is unavailable, making it impossible to pull the valvulotome backward, but rather to push the retrograde valvulotome forward as described herein. FIG. 23B is a schematic perspective view of an exemplary embodiment of a valvulotome 410 that can be used with such a procedure. The retrograde valvulotome 410 has one or more blades 412 (e.g., two to five blades, e.g., three blades) that face forward or distally so as to be able to cut the valve as the retrograde valvulotome 410 advances distally. At least because retrograde access to an attenuated vein has not previously been recognized as a problem, there has previously been no motivation to reverse the direction of the valvulotome blades to create a retrograde valvulotome 410 as described herein. The retrograde valvulotome 410 can be tracked over the guidewire 414 and advanced into the vein to disable the venous valve. After creating a fistula between the artery and the vein as described herein, fluid flow within the vein is in the opposite direction to the original or normal or pre-procedure direction of fluid flow within the vein, and therefore pushing the retrograde valvulotome 410 is in the opposite direction to the original fluid flow, but in the direction of fluid flow after the fistula is created.

[0298] Other systems and methods for disabling valves in veins (e.g., cutting balloons, atherectomy, laser ablation, ultrasonic ablation, heating, radiofrequency (RF) ablation, catheters with advanced and / or retracted traumatic or non-traumatic tips (e.g., introducer sheaths), combinations thereof, etc.) may also be considered.

[0299] It can also be difficult to cross a valve in a vein retrogradely before disabling it. Figure 24 is a schematic perspective view of an exemplary embodiment of a LeMaitre device 420 that can be used to radially expand a vein and, therefore, its valve. The LeMaitre device 420 has expandable elliptical or oblong lobes 422, e.g., a self-expanding nitinol mesh. In some embodiments, a PTA balloon catheter can be used to radially expand the vein and, therefore, its valve. In some embodiments, the vein and, therefore, its valve can be radially expanded by applying a tourniquet to the leg. During radial expansion, a guidewire can be advanced through the expansion valve(s) (e.g., through an expansion device such as a LeMaitre device), and a catheter (e.g., PTA, stent delivery, atherectomy, etc. (e.g., directional, orbital, laser, etc.), etc.) or other over-the-wire device can be advanced over the guidewire.

[0300] 26A and 26B schematically illustrate another exemplary embodiment of a method for performing retrograde perfusion. Referring again to FIG. 20E , a fistula can be created between an artery 600 containing an occlusion 604 and a vein 602 by passing a guidewire 606 using one or more techniques described herein and / or other techniques. As shown in FIG. 26A , a prosthesis delivery system carrying a prosthesis 620 is tracked over the guidewire 606 through the interstitial space between the artery 600 and the vein 602. In some embodiments, a separate PTA balloon catheter (e.g., about 2 mm) can be tracked over the guidewire 606 to pre-dilate the fistula between the artery 600 and the vein 602 prior to introducing the prosthesis delivery system. The use of a PTA balloon catheter can depend, for example, on the radial force of the prosthesis 620. The prosthesis 620 can be the stents 500, 520, 540 of Figures 25A-25C or variations thereof (e.g., as described with respect to Figure 25C) that include uncoated, low-porosity woven filaments configured to divert blood flow.

[0301] The flow diversion characteristics of the uncoated woven filaments may depend on certain hemodynamic characteristics of the vascular lumen. For example, if the occlusion 604 is not complete, allowing some pressure loss between the lumen of the prosthesis 620 and the portion of the artery 600 between the occlusion 604 and the prosthesis 620, blood may potentially flow through the sidewall of the prosthesis 620 rather than through the fistula. Referring again to FIG. 4 and the description of the blocking material 251, a blocking material 608 may optionally be provided in the artery 600 to further occlude the artery 600, thereby preventing hemodynamic effects that may cause and / or enable blood flow through the sidewall of the prosthesis 620. In another example, a pressure loss between the artery 600 and the vein 602 may cause and / or enable blood flow through the sidewall of the prosthesis in the normal direction of blood flow in the vein, rather than through the lumen of the prosthesis to provide retrograde perfusion. Referring again to FIG. 4 and the description of the block material 251, the block material 610 can optionally be provided within the vein 602 to occlude a portion of the vein 602 downstream of the fistula that is under normal venous flow, thereby preventing hemodynamic effects that may cause and / or enable blood flow through the side wall of the prosthesis 620.

[0302] The prosthesis 620 is deployed from the prosthesis delivery system, for example, by manipulating the trigger handle 194 ( FIG. 17 ). In some embodiments, for example, if the prosthesis 620 is unable to expand and / or advance, the prosthesis delivery system can be removed and a PTA catheter (e.g., about 2 mm) can be advanced over the guidewire 620 to attempt to enlarge or further enlarge the fistula between the artery 600 and the vein 602. Deployment of the prosthesis 620 can then be attempted again (e.g., by self-expansion, balloon expansion, etc.). In embodiments in which the prosthesis 620 is self-expanding, the degree of remodeling can vary over time; for example, the prosthesis 620 expands as the blood vessel expands or contracts as the blood vessel contracts. The prosthesis 620 can resemble the anatomy into which it is deployed. For example, in an expanded state on a table or benchtop, the prosthesis 620 can be substantially cylindrical, but the prosthesis 620 can conform to the diameter of the blood vessel and the diameter of the fistula into which the prosthesis 620 is deployed, and the prosthesis can have different diameters in different longitudinal segments, tapered portions, non-cylindrical portions, combinations thereof, etc.

[0303] In some embodiments in which the prosthesis 620 includes a secondary support structure (e.g., as described with respect to FIG. 25B), deploying the prosthesis can include deploying the first woven structure and deploying the secondary support structure before, during, and / or after deploying the first woven structure.

[0304] Optionally, the fistula can be dilated with a PTA catheter before, during, and / or after deployment of 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 artery 600, the diameter of vein 602, the composition of the interstitial tissue, the properties of prosthesis 620, a combination thereof, etc.

[0305] Once the prosthesis 620 is in place, the prosthesis delivery system can be removed, as shown in FIG. 26B, thereby creating an AV fistula between the artery 600 and the vein 602. Even if the prosthesis lacks or does not include a graft material, blood will flow through the lumen of the prosthesis 620 due to the hemodynamic effects of low porosity (e.g., porosity less than about 50% or other values ​​described herein). FIG. 26B shows an embodiment without the use of blocking materials 608, 610. Once the prosthesis 620 is in place, the valves in the vein can be disabled, for example, as described herein.

[0306] In embodiments in which the prosthesis 620 includes two filaments that can be deployed separately (e.g., as described with respect to certain embodiments of FIG. 25B), the filaments can be deployed at least partially simultaneously, sequentially without an intervening step, or sequentially with an intervening step, such as a PTA step, as described herein.

[0307] FIG. 27 schematically illustrates another exemplary embodiment of a prosthesis 720 and a method for performing retrograde perfusion. While some dimensions and even an exemplary scale of "10 mm" are provided, the shape, size, and location of features shown in FIG. 27 may be varied. The prosthesis 720 is positioned within the artery 700, the vein 702, spanning the interstitial tissue T between the artery 700 and the vein 702, including the occlusion 704. The prosthesis 720 may be positioned, for example, as described herein and / or using other methods. In some embodiments, the prosthesis 720 is delivered over a guidewire having an outer diameter of 2 French (0.67 mm) through a delivery system having an inner diameter of 5 French (1.67 mm).

[0308] In some embodiments, the porosity of the first longitudinal section 722, the second longitudinal section 724, and / or the third longitudinal section 726, or one or more portions thereof, can be from about 0% to about 50%, and can vary in ranges therebetween, for example, as described herein. Blood flow from the artery 700 can be diverted through the prosthesis 720 into the vein 702 due to hemodynamic forces, such as a pressure differential 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 ends of the prosthesis 720, e.g., the proximal and / or distal portions having lower porosity, can be configured to appose the sidewalls of the blood vessel because blood is less likely to flow through these portions.

[0309] The techniques described herein can be useful for creating a fistula between two body cavities in the lower extremity, such as near the heart, in the periphery, or even in the plantar arch. Figures 28A and 28B show schematic diagrams of the arteries and veins of the foot, respectively. A fistula or anastomosis can be created between two blood vessels in the foot. In one example, an arterial-venous passage is created from the lateral plantar artery to the lateral plantar vein in the mid-lateral plantar.

[0310] The artery supplying the foot was occluded, and the subintimal space was calcified. A wire was advanced distally and crossed into the adjacent vein. The hole between the artery and vein was dilated using a 1.5 mm balloon, for example, because a small arteriovenous fistula should not cause significant damage (if any) to the patient at that location. After dilation, blood began to flow from the artery into the vein without leakage. After such flow was confirmed, further dilation of the space was performed using larger balloons (2.0 mm, 2.5 mm, 3.0 mm) at higher pressures (e.g., 20 atm-30 atm). Surprisingly, leakage was minimal or nonexistent, even without the placement of a stent, graft, scaffold, or other type of device. A prosthetic-free procedure can reduce cost, manufacturing time, complexity, or a combination thereof. The lateral plantar vein is an excellent candidate for supplying blood to that part of the foot because it directly connects to the venous arch of the forefoot. The patient had significant leg pain before the procedure, but after the procedure the leg pain was gone, indicating that blood supply by venous retrograde flow was now possible, as described herein. For certain situations, such as hemodialysis, where the distal or lower extremity arteries and veins can be described as "glued" to the surrounding tissue (e.g., the mid-lateral plantar arteries and veins), the fistula or anastomosis maintenance device may optionally be omitted.

[0311] In some situations, a fistula or anastomosis maintainer can optionally be used. Multiple fistula maintainers are described herein. FIG. 29 schematically illustrates an exemplary embodiment of an anastomosis device 800. The anastomosis device has a first section 802, a second section 804, and, optionally, a third section 806 longitudinally disposed between the first section 802 and the second section 804. The first section 802 can be configured for placement within a first body lumen (e.g., a blood vessel such as an artery or vein). The first section 802 can include expandable members, barbs, etc. The second section 804 can be configured for placement within a second body lumen (e.g., a blood vessel such as an artery or vein, which can be of the opposite type from the first body lumen). The third section 806 can be configured to span the lumen of the first and second body lumen. In some embodiments, the space between the lumen of the first body cavity and the second body cavity generally comprises a blood vessel wall, allowing the size of the third section 806 to be reduced or even eliminating the third section 806.

[0312] Several anastomosis devices are available and / or being developed for treating holes in larger vessels (e.g., Medtronic's Spyder, Johnson and Johnson's CorLink, St. Jude Medical's Symmetry, Cardica's PAS-Port, and ROX Medical's ROX Coupler). Such devices may be suitable for use in the distal or lower extremities, e.g., if resized and / or reconfigured. Other devices may also be considered.

[0313] FIG. 30 schematically illustrates an exemplary embodiment of two blood vessels 902 and 904 joined together by an anastomotic device 800 that spans the walls of the blood vessels 902, 904. The blood vessel 902 is an artery, as shown schematically by having a thick wall, and the blood vessel 904 is a vein. Other combinations of blood vessels and other body lumens are also contemplated. After a passageway 906 is formed between the first blood vessel 902 and the second blood vessel 904, the anastomotic device 800 is deployed, for example, as described herein (e.g., using a wire, an deployable needle, one or more balloons, etc.). For example, the distal end of the anastomotic device 800 deployment system can reside within the first blood vessel 902 and partially extend through the passageway 906. The first section 802 of the anastomotic device 800 can be deployed through the passageway 906 into the second blood vessel 904. Upon deployment, the first section 802 can self-expand, for example, to appose the walls of the second blood vessel 904. The third section 806 of the anastomotic device 800 can be deployed through the passageway 906. Upon deployment, the third section 806 can, for example, self-expand to appose tissues surrounding the passageway 906 and maintain patency through the passageway 906. The second section 804 of the anastomotic device 800 can be deployed within the first blood vessel 902. Upon deployment, the second section 804 can, for example, self-expand to appose the walls of the first blood vessel 902. One or more of the first section 802, second section 804, and third section 806 can be expanded using a balloon. Different balloons or series of balloons can be used for the different sections 802, 804, 806 of the anastomotic device 800.

[0314] 32A through 32D illustrate an exemplary method and apparatus for identifying and avoiding a bifurcation 1104 in a percutaneous bypass procedure. A first blood vessel 1000 (e.g., an artery) is occluded by an occlusion 1008. The occlusion 1008 may be partial or complete (e.g., causing critical limb ischemia). A percutaneous procedure, such as that described herein, can bypass the occlusion 1008 using a second blood vessel 1002 (e.g., a vein). A first catheter 1010 resides within the first blood vessel 1000. A second catheter 1020 resides within the second blood vessel 1002. The second blood vessel 1002 includes a bifurcation 1004 at a junction with a branch or collateral vessel 1006. The first catheter 1010 includes an ultrasound transmitter 1012 (e.g., a directional transmitter) configured to transmit a signal 1014 to an ultrasound receiver 1022 (e.g., omnidirectional reception) of a second catheter 1020 within the second blood vessel 1002, for example, as described herein. A needle 1016 ( FIG. 32D ) can extend from the first catheter 1010 toward the second blood vessel 1002. In the configuration shown in FIG. 32A , if the needle 1016 extends at the same angle as the signal 1014, for example, as described herein (e.g., FIG. 3 ), the needle 1016 can extend into the bifurcation 1004 and branch vessel 1006. Subsequent navigation of a guidewire through the lumen of the needle 1016 may disadvantageously enter the branch vessel 1006 rather than the second blood vessel 1002. Navigation into the branch vessel 1006 rather than the second blood vessel 1002 may be difficult to detect by a user.

[0315] FIG. 32B illustrates a first step of an exemplary method for diagnosing the presence and / or location of a bifurcation 1004. The expandable member 1024 is expanded, for example, by providing a fluid flow (e.g., saline, contrast, etc.) through an inflation lumen 1026 that is in fluid communication with the expandable member. In FIGS. 32A-32D, a second catheter 1020 includes an integral expandable member 1024 (e.g., including a balloon) and inflation lumen 1026. A separate catheter including an expandable member can be used in the second blood vessel 1002. Expansion of the expandable member 1024 occludes the second blood vessel 1002. As indicated by arrow 1027, blood still flows toward the expandable member 1020 from both the proximal end of the second blood vessel 1002 and the branch vessel 1006. The occlusion of the second blood vessel 1002 and the blood still flowing into the second blood vessel 1002 can dilate the second blood vessel 1002. The dilation of the second blood vessel 1002 can make the second blood vessel easier to target and / or puncture with the needle 1016.

[0316] 32C illustrates the introduction of a contrast agent 1028 into the second blood vessel 1002. The contrast agent 1028 can be delivered through an injection port integral with the second catheter 1020 and / or using a separate catheter within the second blood vessel 1002. The contrast agent 1028 can include a contrast agent or medium configured to improve fluoroscopy, including, for example, iodine-based, barium sulfate-based (e.g., in subjects with impaired renal function), combinations thereof, etc. The contrast agent 1028 can contribute to the dilation of the second blood vessel 1002. The contrast agent 1028 flows until it reaches the expandable member 1024, after which it begins to collect near the expandable member 1024. A portion of the contrast agent 1028 collects at the bifurcation 1004, allowing the presence and location of the bifurcation 1004 and / or branch vessels 1006 to be visualized under fluoroscopy. Without the expandable member 1024, the contrast agent 1028 would flow through the second vessel 1002 without revealing the bifurcation 1004 and / or branch vessel 1006. With knowledge of the angle of the needle 1016 and the position of the first catheter 1010, the user can determine whether the needle 1016 extends into the bifurcation 1004 and / or branch vessel 1006. This situation generally results in an ineffective bypass, so a different puncture site for creating the fistula can be selected.

[0317] In Figure 32D, the first catheter 1010 has been retracted a distance 1018. The ultrasound signal 1014 (Figure 32A) from the first catheter 1010 can be used to target the second catheter 1020. The procedure shown in Figures 32B and 32C can be repeated, for example, to search for another bifurcation. Once the user is satisfied that the needle 1016 has punctured the second blood vessel 1002 at a location without a bifurcation to inhibit or prevent advancement into the branch vessel but not into the second blood vessel 1002, the needle 1016 can be extended from the first catheter 1010, out of the first blood vessel 1000, through the interstitial tissue between the first blood vessel 1000 and the second blood vessel 1002, and into the second blood vessel 1002 at a location where the second blood vessel 1002 does not contain a bifurcation or branch vessel. The needle 1016 can be extended even when the expandable member 1024 is in an inflated or deflated state or when the second catheter 1020 is removed from the second blood vessel 1002. In some embodiments, a permanent occluder can be placed in the second blood vessel 1002, for example, as described herein (e.g., FIG. 4 ). A guidewire can be tracked through the lumen of the needle 1016, and other procedures described herein, such as fistula dilation, fistula prosthesis deployment, stent graft deployment, retrograde valvulotomy, etc., can be performed by tracking a catheter over the guidewire (e.g., through the first blood vessel 1000, through the fistula, and then through the second blood vessel 1002). In some embodiments, the devices and methods described herein can be used to guide a needle into a bifurcation and / or branch vessel, if desired by a user.

[0318] 33A and 33B schematically illustrate an exemplary procedure that may be performed following connection of a first blood vessel 1100 (e.g., an artery) and a second blood vessel 1102 (e.g., a vein) with a needle 1116 that traverses interstitial tissue 1101. The needle 1116 extends from a first catheter 1110 within the first blood vessel 1100. The first blood vessel 1100 is occluded by an occlusion 1108. In FIG. 33A, a guidewire 1118 extends through a lumen within the needle 1116 and can then be navigated through the second blood vessel 1102. The needle 1116 can be retracted upon placement of the guidewire 1118, and the first catheter 1110 can be retracted from the first blood vessel 1100. As shown in Figure 33B, a second catheter 1120 can be tracked over a guidewire 1118 through the first blood vessel 1100, through the interstitial tissue 1101, and into the second blood vessel 1102. In Figure 33B, the second catheter 1120 includes a balloon catheter including a balloon 1122 (e.g., a PTA balloon). Inflation of the balloon 1122 can enlarge a fistula formed between the first blood vessel 1100 and the second blood vessel 1102. The enlargement of the opening in the interstitial tissue 1101 and / or blood vessels 1100, 1102 can enhance subsequent procedures, such as placement of a prosthesis across the fistula.

[0319] 34A through 35F illustrate an exemplary procedure that can be performed when a guidewire 1118 is within a blood vessel 1102 (e.g., a vein). In FIG. 34A, a prosthesis 1124 is positioned across the interstitial tissue 1101 between a first blood vessel 1100 within a second blood vessel 1102. A deployment system for positioning the prosthesis 1124 may be tracked over the guidewire 1118. A catheter 1130A is tracked over the guidewire 1118 distal to the prosthesis 1124. As shown in FIG. 34B, the catheter 1130A can be tracked all the way toward the subject's heel 1103.

[0320] As shown in FIG. 34C, catheter 1130A is configured to deliver a first stent graft 1132A that can, for example, line second vessel 1102, disable a valve in second vessel 1102, occlude a branch vessel of second vessel 1102, etc., as described above. In FIG. 34D, catheter 1130A has been retracted, and another catheter 1130B is tracked over guidewire 1118. FIG. 34D also illustrates an example in which occlusion 1108 in first vessel 1100 can be terminated, which can be useful if another fistula is formed between first vessel 1100 and second vessel 1102 (e.g., to bypass occlusion 1108). Forming the second fistula can be the same or different from forming the first fistula (e.g., using at least one of ultrasound guidance, needle extension, and prosthesis deployment as described herein). In Figure 34E, catheter 1130B delivers second stent graft 1132B, which can at least partially overlap first stent graft 1132A in region 1133. In some embodiments, the distal end of second stent graft 1132B can be configured to overlap the proximal end of first stent graft 1132A. In some embodiments, the proximal end of first stent graft 1132A can be configured to overlap the distal end of second stent graft 1132B. In some embodiments, for example, when second stent graft 1132B is deployed first, the proximal end of first stent graft 1132A can be configured to overlap the distal end of second stent graft 1132B. The second stent graft 1132B may be longitudinally spaced apart from the first stent graft 1132A, for example, if the longitudinal spacing is sufficiently small that branch vessels and / or valves are unlikely to be present at that spacing.

[0321] In Figure 34F, the second stent graft 1132B at least partially overlaps the prosthesis 1124. In some embodiments, the proximal end of the second stent graft 1132A can be configured to overlap the distal end of the prosthesis 1124. In some embodiments, the distal end of the prosthesis can be configured to overlap the proximal end of the second stent graft 1132B. The second stent graft 1132B can be longitudinally spaced from the prosthesis 1124, for example, if the longitudinal spacing is small enough that branch vessels and / or valves are unlikely to be present at that location. Figure 34F also shows the catheter 1132B retracted from the vasculature. Although two stent grafts 1132A, 1132B are described in this example, one, two, three, or more stent grafts may be used depending, for example, on the length of the second vessel 1102 distal to the prosthesis 1124, the length of the stent grafts, the possibility or presence of branch vessels, etc.

[0322] FIG. 35A shows a second blood vessel 1102 distal to a first stent graft 1132A. The second blood vessel 1102 includes a first valve 1105A that inhibits or prevents blood 1111 from flowing distal to the first valve 1105A. In FIG. 35B, a catheter 1140 is tracked over a guidewire 1118 through the stent graft 1132A toward the first valve 1105A. The catheter 1140 includes a valve override device. In FIG. 35C, the catheter 1140 is shown including a retrograde valvulotome 1142, for example, as described herein, and a sheath 1144. Referring again to FIG. 35B, when the retrograde valvulotome 1142 is within the sheath 1144, the retrograde valvulotome 1142 is in a radially contracted state. As shown in Figure 35C, when the sheath 1144 is retracted proximally and / or the retrograde valvulotome 1142 is advanced distally, the retrograde valvulotome 1142 radially expands to a state configured to cut the valve upon distal advancement. In Figure 35D, one or more blades of the retrograde valvulotome 1142 cut or sever or sever the leaflets of the first valve 1105A, allowing blood 1111 to flow distally of the first valve 1105A.

[0323] Referring to FIG. 35E, after the first valve 1105A is disabled, the retrograde valvulotome 1142 can be radially compressed within the outer sheath 1144 to advance further distally without impacting the second vessel 1102. As shown in FIG. 35F, upon encountering the second valve 1105B, the retrograde valvulotome 1142 extends from the sheath 1144 and then advances distally to disable the second valve 1105B and allow blood 1111 to flow distal to the second valve 1105B. Use of the retrograde valvulotome 1142 can be repeated for as many valves in the second vessel 1102 as desired by the user. In some embodiments, the retrograde valvulotome 1142 can be used prior to placement of the stent grafts 1132A, 1132B. For example, but not limited to the bidirectional valvulotome 1300 described herein, valve override devices other than retrograde valvulotomes may also or alternatively be used.

[0324] 36A through 36D illustrate a method for promoting retrograde perfusion of blood through veins to the toes. In FIG. 36A , the illustrated vasculature includes a lateral plantar vein 1200, a deep plantar venous arch 1202, metatarsal veins 1204, and a medial plantar vein 1206. As indicated by arrow 1201, blood flow through the lateral plantar vein 1200 is opposite the normal direction of blood flow due to retrograde perfusion caused, for example, by a percutaneous bypass from an artery to a vein upstream of the lateral plantar vein 1200. Blood continues to flow through the vasculature, as indicated by arrow 1203, where it is joined by blood flowing away from the toes in the normal direction of blood flow through the metatarsal vein 1204, as indicated by arrow 1205. The medial plantar vein 1206 is configured to direct blood back toward the heart, thereby maintaining normal blood flow, as indicated by arrow 1207. As shown in Figure 36A, blood may flow preferentially, which is undesirable if the intended effect of retrograde perfusion is to perfuse oxygenated blood to the toes.

[0325] FIG. 36B shows an exemplary embodiment of a device that can be used to promote blood flow to the toes through the metatarsal veins 1204. A first catheter 1210 including a first expandable member 1212 (e.g., a balloon) can include a 6 French occlusion catheter including a three-way fitting. The expandable member 1212 is inflated within the lateral plantar vein 1200. A second catheter 1220, coaxial with the first catheter 1210, extends through the expandable member 1212, through the deep plantar venous arch 1202, and into the medial plantar vein 1206. The second catheter 1220 includes an expandable member 1222 (e.g., a balloon) that can be inflated within the medial plantar vein 1206. At that point, the medial planar vein 1206 is partially or completely occluded, and blood flow through the medial plantar vein 1206 is inhibited or prevented. As indicated by the persistence of arrow 1205, blood can continue to flow from the toes through the metatarsal veins 1204. Because the blood has no exit route, hydrostatic pressure can build up in the deep plantar venous arch 1202, which can disable valves and / or other structures configured to facilitate normal blood flow. If necessary, the first expandable member 1212 can allow retrograde perfusion blood to flow, which can further build pressure within the deep plantar venous arch 1202. Although blood flow normally flows counter to the direction of retrograde perfusion in the lateral plantar vein 1200, the expandable member 1212 can inhibit or prevent such flow.

[0326] In some embodiments, a device including a single catheter can be used to promote blood flow to the toes through the metatarsal veins 1204. The device can include a first expandable member and a second expandable member. For example, the device can include a dual balloon catheter having a first balloon and a second balloon distal to the first balloon.

[0327] The device can allow one of the first and second expandable members to expand independently of the other expandable member. For example, in some embodiments, the device can include at least a first lumen and a second lumen. The first lumen can be configured to expand the first expandable member independently of the second expandable member. The second lumen can be configured to expand the second expandable member independently of the first expandable member. The device can include a single lumen configured to expand both the first and second expandable members. The device can include one or more inflation ports configured to expand at least one of the first and second expandable members.

[0328] The device can be configured to adjust the distance between the expandable members before inflation of at least one of the expandable members. The device can allow the expandable members to isolate a patient-specific treatment area and promote retrograde perfusion of blood through the veins to the toes, as described herein. For example, the device can allow placement of a first expandable member in the lateral plantar vein 1200 and a second expandable member in the medial plantar vein 1206, and / or vice versa. The device can include one or more handles configured to control movement of various portions of the device. For example, the device can include a first handle for controlling movement of both the first and second expandable members. In some embodiments, the device can include a second handle configured to control movement of the first expandable member independently of the second expandable member. The second handle can allow the device to advance the first expandable member proximally relative to the second expandable member from a first position to a second position. After the first expandable member is advanced to the second position, the second handle can enable the device to advance the first expandable member distally to the first position.

[0329] The device can include an injection port configured to inject fluid into a treatment area defined by the first and second expandable members. For example, the treatment area can include the deep plantar venous arch 1202. After the first and second expandable members are inflated, blood flow through the medial plantar vein 1206 is inhibited or prevented. The injection port can then enable the device to inject fluid into the treatment area. The injection of fluid can increase hydrostatic pressure within the treatment area. The hydrostatic pressure increases because the inflated first and second expandable members prevent the injected fluid from flowing out of the treatment area through the medial plantar vein 1206 and / or the lateral plantar vein 1200. The injection port can be configured to sufficiently increase hydrostatic pressure within the treatment area so that the device can override valves and / or other structures. For example, the injection port can be sized to inject a sufficient amount of fluid to increase the hydrostatic pressure to promote blood flow to the toes.

[0330] 36C , blood flow is permitted through the expandable member 1212, as indicated by arrow 1201, but the expandable member 1212 inhibits normal blood flow in the deep plantar venous arch 1202. Pressure from the restricted flow builds up in the deep plantar venous arch 1202. The pressure buildup, in combination with blood flow from the lateral plantar vein 1200, can optionally cause backflow of blood into the metatarsal vein 1204, as indicated by arrow 1209.

[0331] In FIG. 36D , the first catheter 1210 and the second catheter 1220 have been removed. The elimination of normal vasculature in the deep plantar venous arch 1202 causes continued retrograde perfusion of blood through the metatarsal veins 1204, as indicated by the maintenance of arrows 1209. A small amount of oxygenated blood can flow through the medial plantar vein 1206. In some embodiments, the medial plantar vein 1206 can remain occluded using an expandable member 1222 (e.g., detachable from the catheter 1220) or a different occluder. In some embodiments, blood can flow through the plantar vein 1206 in a direction opposite to the normal blood flow.

[0332] 37A shows an example of a valve defeat device 1300 in a radially expanded state. The valve defeat device 1300 is configured to cut, resect, sever, or defeat the leaflets of a valve (e.g., a venous valve) upon retraction and / or advancement in the radially expanded state. The valve defeat device 1300 includes a proximal portion 1308, a distal portion 1306, and an intermediate portion 1302 between the proximal portion 1308 and the distal portion 1306. The proximal portion 1308 includes a tubular element. The distal portion 1306 includes a tubular portion. The device 1300 can be formed by cutting (e.g., laser cutting) hypotube, cutting a flat sheet and rolling it into a hypotube to form components of the device 1300, and then joining the components together, shape setting, combining thereof, etc. The tubing elements of the distal portion 1306 and / or the tubing elements of the proximal portion 1308 can comprise uncut portions of hypotubes or sheets.

[0333] The proximal portion 1308 can be coupled to a pusher element 1320. The pusher element can include a lumen configured for advancement over, for example, a guidewire. The device 1300 can be in a radially compressed state when confined within the sheath 1304 and in a radially expanded state when not confined within the sheath 1304. The device 1300 can be radially expanded by proximally retracting the sheath 1304 and / or by distally advancing the pusher element 1320, and thereby the device 1300. The device 1300 can be radially compressed by distally advancing the sheath 1304 and / or by proximally retracting the pusher element 1320, and thereby the device 1300. In the radially expanded state, the intermediate portion 1302 can be radially expanded, while the proximal portion 1308 and the distal portion 1306 do not radially expand (e.g., as shown in FIG. 37A ).

[0334] The intermediate portion 1302 can include a cut portion of a hypotube or sheet. The intermediate portion 1302 can include one or more struts 1316 extending between the proximal portion 1308 and the distal portion 1306. The intermediate portion 1302 can include from about 1 strut to about 8 struts (e.g., 1 strut, 2 struts, 3 struts (e.g., as shown in FIG. 37A), 4 struts, 5 struts, 6 struts, 7 struts, 8 struts, ranges between these values, etc.). The struts 1316 can be approximately equally spaced circumferentially, for example, to provide a uniform cut in any circumferential direction. For example, three struts 1316 can be spaced approximately 120° apart circumferentially. The struts 1316 can be unequally spaced circumferentially, for example, to provide more cut in a particular circumferential region. For example, the first strut 1316 may be circumferentially spaced approximately 135° from the second strut 1316, and may be circumferentially spaced approximately 135° from the third strut 1316, and the second strut 1316 may be circumferentially spaced approximately 90° from the third strut 1316.

[0335] The strut 1316 can include from about 1 to about 4 blades (e.g., 1 blade, 2 blades (e.g., as shown in FIG. 37A), 3 blades, 4 blades, ranges between these values, etc.). The strut 1316 shown in FIG. 37A includes a first blade 1312 and a second blade 1314. The first blade 1312 faces proximally and is configured to cut when the device 1300 is retracted proximally. The second blade 1314 faces distally and is configured to cut when the device 1300 is advanced distally. The proximal-facing blade 1312 and the distal-facing blade 1314 allow the device 1300 to defeat the valve when retracted proximally and / or advanced distally, providing flexibility as a bidirectional valvulotome. Other configurations are possible. For example, a first strut 1316 can include a proximally facing blade 1312, and a second strut 1316 can include a distally facing blade 1314. In another example, a first strut 1316 can include a plurality of proximally facing blades 1312, and a second strut 1316 can include a plurality of distally facing blades 1314. In another example, a first strut 1316 can include a proximally facing blade 1312 and a distally facing blade 1314, and a second strut 1316 can include zero blades, or no blades or a lack of blades. In another example, a first strut 1316 can include a proximally facing blade 1312 and a distally facing blade 1314, and a second strut 1316 can include a distally facing blade 1314. In another example, the first strut 1316 can include two proximally facing blades 1312 and one distally facing blade 1314 .

[0336] FIG. 37B is a flattened side view of the valve deactivation device 1300 of FIG. 37A. The device 1300 can be cut from a flat sheet that is wrapped around a hypotube. FIG. 37B provides an exemplary cut pattern that can be used to form the device 1300. The cut pattern shown in FIG. 37B can also be on a round hypotube. FIG. 37B provides some exemplary dimensions of the device 1300. The length 1340 of the distal portion 1306 can be about 0.1 mm to about 3 mm (e.g., about 0.1 mm, about 0.5 mm, about 1 mm, about 1.5 mm, about 2 mm, about 3 mm, ranges between these values, etc.). The distal portion 1306 can have a length 1340 configured to provide a stable joint for the distal end of the strut 1316. The circumferential length 1342 of the distal portion 1306 can be about 1.5 mm to about 5 mm (e.g., about 1.5 mm, about 2 mm, about 2.5 mm, about 3 mm, about 3.5 mm, about 4 mm, about 5 mm, ranges between these values, etc.)...

Claims

1. A device for disabling a valve in a blood vessel, comprising: a mesh structure having a plurality of interconnected struts and expandable from a compressed position within a delivery catheter to an expanded position within the blood vessel; a plurality of blades, each of the plurality of blades extending from a respective one of the plurality of struts; Equipped with the mesh structure is configured to move through the blood vessel in an expanded state, and the plurality of blades at least partially cut the valve to disable the valve. Device.

2. The plurality of blades are arranged at equal intervals in the circumferential direction around the mesh structure.

10. The apparatus of claim 1.

3. the plurality of blades includes four blades; 10. The apparatus of claim 1.

4. The plurality of blades are arranged at equal intervals of 90 degrees around the mesh structure in the circumferential direction.

4. The apparatus of claim 3.

5. a first blade of the plurality of blades is longitudinally offset along the mesh structure relative to a second blade of the plurality of blades; 10. The apparatus of claim 1.

6. The plurality of blades are integrally formed with the corresponding respective struts.

10. The apparatus of claim 1.

7. each of the plurality of blades extends circumferentially relative to a longitudinal axis of the mesh structure, such that the plurality of blades do not cut the blood vessel when the mesh structure is in the expanded state within the blood vessel; 10. The apparatus of claim 1.

8. Each of the plurality of blades has a curved shape.

10. The apparatus of claim 1.

9. the plurality of blades are configured to at least partially cut the valve to disable the valve when the mesh structure is moved proximally through the blood vessel.

10. The apparatus of claim 1.

10. the plurality of blades are configured to at least partially cut the valve to disable the valve when the mesh structure is moved distally through the blood vessel.

10. The apparatus of claim 1.

11. the plurality of blades are configured to at least partially cut the valve to disable the valve when the mesh structure is moved proximally through the blood vessel and when the mesh structure is pushed distally through the blood vessel.

10. The apparatus of claim 1.

12. the mesh structure is configured to self-expand from the compressed position to the expanded position.

10. The apparatus of claim 1.

13. the mesh structure comprises cut hypotubes; 10. The apparatus of claim 1.

14. The valve is a venous valve.

10. The apparatus of claim 1.

15. the delivery catheter and the mesh structure are movable relative to one another, and the mesh structure is moved from the delivery catheter to allow the mesh structure to expand from the compressed position to the expanded position.

10. The apparatus of claim 1.

16. further comprising the delivery catheter.

16. The apparatus of claim 15.

17. A device for disabling a valve in a blood vessel, comprising: a mesh structure having a plurality of interconnected struts and expandable from a compressed position within a delivery catheter to an expanded position within the blood vessel; a plurality of blades, each of the plurality of blades extending from a respective one of the plurality of struts; an elongated member extending from the mesh structure, the elongated member configured to be moved while the mesh structure is in an expanded state within the blood vessel such that the mesh structure is moved and the plurality of blades at least partially cut the valve, disabling the valve; and Equipped with Device.

18. The plurality of blades includes four blades, and the plurality of blades are equally spaced circumferentially around the mesh structure.

18. The apparatus of claim 17.

19. a first blade of the plurality of blades is longitudinally offset along the mesh structure relative to a second blade of the plurality of blades, and the plurality of blades are integrally formed with a corresponding one of the plurality of struts; 18. The apparatus of claim 17.

20. Each of the plurality of blades extends circumferentially relative to a longitudinal axis of the mesh structure, and is configured so as not to cut the blood vessel when the mesh structure is in the expanded state within the blood vessel, and each of the plurality of blades has a curved shape.

18. The apparatus of claim 17.

21. the plurality of blades are configured to at least partially cut the valve to disable the valve at least when the elongated member is pulled in a proximal direction and when the elongated member is pushed in a distal direction.

18. The apparatus of claim 17.

22. the elongated member comprises a hypotube and the mesh structure comprises a cut hypotube; 18. The apparatus of claim 17.

23. the valve is a venous valve and the blood vessel is a vein in the patient's leg; 18. The apparatus of claim 17.

24. the delivery catheter and the mesh structure are movable relative to one another, and the mesh structure is moved from the delivery catheter to allow the mesh structure to expand from the compressed position to the expanded position.

18. The apparatus of claim 17.

25. A device for disabling a valve in a blood vessel, comprising: a unitary structure extending along a longitudinal axis, the unitary structure including a plurality of interconnected struts, the unitary structure being expandable from a compressed position within a delivery catheter to an expanded position within the blood vessel; a plurality of blades, each extending from a respective one of the plurality of struts and substantially equally spaced circumferentially about the longitudinal axis in the expanded position; Equipped with the unitary structure is configured to be moved through the blood vessel in an expanded state, and the plurality of blades at least partially cut the valve to disable the valve. Device.

Images