Methods and systems for providing or maintaining fluid flow through body channel

Abstract

The invention provides a method and system for providing or maintaining fluid flow through a body channel. An apparatus includes a first end, a second end, an intermediate portion, and a graft material. The first end has a first end diameter. The second end portion has a second end diameter less than the first end diameter. The first end portion includes a first material. The second end portion includes a second material different from the first material. The intermediate portion is between the first end portion and the second end portion. The intermediate portion tapers between the first end portion and the second end portion. The graft material is bonded to at least the middle portion.

Description

[0001] This application is a divisional application. The filing date of the original application is February 28, 2014, the application number is 2014800129330, and the invention title is "Methods and Systems for Providing or Maintaining Fluid Flow Through a Body Passageway".

[0002] Incorporated by reference

[0003] U.S. Patent Application No. 13 / 791,185, filed on March 8, 2013; U.S. Provisional Patent Application No. 61 / 901,753, filed on November 8, 2013; U.S. Patent Application No. 11 / 662,128, filed on January 3, 2008; U.S. Patent Application No. 14 / 141,913, filed on December 27, 2013; and U.S. Patent Application No. 12 / 297,498, filed on February 25, 2009 - which is the national stage of PCT / GB2007 / 001430, filed on April 20, 2007, and published as U.S. Patent Application No. 8,439,963 on May 14, 2013 - are hereby incorporated by reference in their entirety. Background Technical Field

[0005] This application relates to methods and systems used in percutaneous interventional procedures. In particular, this application relates to methods and systems for providing or maintaining fluid flow through body passageways such as heart cavities and blood vessels.

[0006] Description of Related Fields

[0007] Minimally invasive percutaneous surgery or "key-hole" surgery is a surgical technique in which surgical devices are inserted through small incisions made in the skin into the patient's body cavity. This form of surgery has become increasingly popular because it subjects the patient to less surgical discomfort while maintaining the benefits of traditional surgery. Patients treated with this technique are exposed to lower levels of discomfort, the need for general anesthesia, the risks of trauma and infection, and their recovery time can be significantly reduced compared to traditional surgical procedures.

[0008] For example, keyhole surgery can be used in laparoscopic surgery and for treating cardiovascular diseases. In treating cardiovascular diseases, balloon angioplasty can be used as an alternative to open heart surgery for treating partially occluded coronary arteries. In balloon angioplasty, a balloon catheter is inserted into an artery, usually near the patient's groin, and guided to the patient's heart. At the distal portion of the catheter in the heart, the balloon is inflated to widen or expand the occluded blood vessel, thereby helping to restore blood flow to the heart tissue. A tubular support device (e.g., a stent) can be deployed at the occluded site to prevent future occlusion (restenosis) or collapse of the blood vessel. For example, a stent can be an expandable metal mesh tube carried on the balloon of a balloon catheter or can be self-expanding. When the balloon is inflated, the balloon-expandable stent expands so that the stent pushes against the blood vessel wall. When the stent reaches its expanded position, for example, by plastic deformation or by means of a mechanical locking mechanism, the stent is arranged to maintain its expanded shape, thereby forming an elastic stent or support in the blood vessel. This support structure (e.g., a stent) supports the blood vessel wall and expands the blood vessel wall to maintain a path for blood to flow through the blood vessel. Self-expanding stents can also be utilized, which are kept in a collapsed state for transportation through the artery by a suitably modified catheter and assume an expanded state when deployed at the occluded site. For example, the catheter can include a retaining sleeve that keeps the stent in a compressed or unexpanded state. Once the sleeve is removed or retracted from the stent, the stent expands to support and expand the blood vessel wall.

[0009] Balloon angioplasty is not always a suitable measure, for example, in acute cases and in situations where the coronary artery is completely occluded. In these cases, the usual treatment is coronary artery bypass. Coronary artery bypass surgery is an open-chest or open-heart procedure and generally involves grafting a piece of healthy blood vessel onto the coronary artery to bypass the occlusion and restore blood flow to the coronary tissue. The healthy blood vessel is usually a vein taken from the patient's leg or arm during the bypass surgery. To perform this procedure, the patient's heart must be exposed by opening the chest cavity, separating the breastbone, and cutting through the pericardium surrounding the heart, which results in significant surgical trauma.

[0010] Traditional coronary artery bypass surgery is not always an option. Some patients are not suitable candidates for traditional coronary artery bypass surgery due to low expectations or high risks of recovery from the significant trauma caused by the surgery, high risks of infection, lack of healthy blood vessels for use as bypass grafts, significant co-morbidities, and the expected long and complex recovery time associated with open-chest surgery. For example, factors such as diabetes, age, obesity, and smoking can exclude some candidate patients who truly need this treatment. Summary of the Invention

[0011] The present application provides methods and systems for overcoming certain deficiencies and / or improving percutaneous methods and systems. For example, according to several embodiments, the methods and systems described herein can improve the targeting and positioning of therapeutic administration, which can advantageously provide treatment to patients not suitable for more invasive procedures via percutaneous techniques. Certain embodiments described herein can provide fluid flow in conduits such as coronary and / or peripheral blood vessels by creating a bypass using minimally invasive percutaneous surgical techniques.

[0012] In some embodiments, a method of diverting fluid flow from a first conduit to a second conduit includes deploying a device in a third conduit between the first conduit and the second conduit. The device includes a first end, a second end, an intermediate portion, and graft material. The first end has a first end diameter. The second end has a second end diameter that is greater than the first end diameter. The intermediate portion is located between the first end and the second end. The intermediate portion tapers between the first end and the second end. The graft material is at least bonded to the intermediate portion. The method further includes expanding the first end against the sidewall of the first conduit and expanding the second end against the sidewall of the second conduit.

[0013] The first conduit can be an artery and the second conduit can be a vein. The first conduit can be a coronary artery and the second conduit can be a coronary vein. The method can further include expanding the third conduit. The first conduit can be a peripheral artery and the second conduit can be a peripheral vein. The method can further include expanding the third conduit. Expanding the third conduit can include expanding the intermediate portion. The first conduit can be substantially parallel to the second conduit. The intermediate portion can conform to an "S" shape. Expanding the first end and the second end can include self-expanding the first end and the second end. Expanding the first end and the second end can include balloon-expanding at least one of the first end and the second end. Expanding one of the first end and the second end can include self-expanding one of the first end and the second end and expanding the other of the first end and the second end can include balloon-expanding the other of the first end and the second end. The method can further include expanding the intermediate portion.

[0014] In some embodiments, a device includes a first end, a second end, an intermediate portion, and graft material. The first end has a first end diameter. The second end has a second end diameter that is less than the first end diameter. The intermediate portion is located between the first end and the second end. The intermediate portion tapers between the first end and the second end. The graft material is at least bonded to the intermediate portion.

[0015] At least one of the first end portion and the second end portion can be generally cylindrical. The first end portion can be generally cylindrical and the second end portion can be generally cylindrical. The first end portion can taper between a first end diameter and a middle portion or the second end portion can taper between a second end diameter and a middle portion. The first end portion can taper between a first end diameter and a middle portion and the second end portion can taper between a second end diameter and a middle portion. The first end portion can include a first type of material, the second end portion can include a second type of material, and the middle portion can include a third type of material. The first type of material can include a first cutting material, the second type of material can include a second cutting material, and the third type of material can include filaments. The first cutting material can include cobalt-chromium alloy, the second cutting material can include nitinol, and the filaments can include nitinol. The first type of material can include a cutting material, the second type of material can include a cutting material, and the third type of material can include filaments. The cutting material can include nitinol and the filaments can include nitinol. At least one of the first end portion, the second end portion, the middle portion, and the graft material can include a bioabsorbable material. At least some of the graft material can be external to the middle portion. At least some of the graft material can be internal to the middle portion. At least some of the graft material can be embedded within the middle portion. The device can be capable of maintaining or configured to maintain fluid flow between a first channel and a second channel, with the first end portion fixed within the first channel and the second end portion fixed within the second channel. The first channel can be substantially parallel to the second channel. The middle portion can conform to an "S" shape.

[0016] In some embodiments, the device includes a first end portion, a second end portion, a middle portion, and a graft material. The first end portion includes a first material. The second end portion includes a second material different from the first material. The middle portion is located between the first end portion and the second end portion. The graft material is at least bonded to the middle portion.

[0017] The first material may include nitinol and the second material may include cobalt chrome. The first material may include nitinol and the second material may include stainless steel. The first end may include cutting struts and the second end may include filaments. The first end may include cutting struts and the second portion may include cutting struts. The first material may include an alloy and the first end may include struts or filaments having a first thickness, and the second material may include an alloy and the second end may include struts or filaments having a second thickness different from the first thickness. The intermediate portion may include a third material. The third material may include nitinol. The intermediate portion may include filaments. The intermediate portion may include cutting struts. At least one of the first end and the second end may be generally cylindrical. At least one of the first end, the second end, the intermediate portion, and the graft material may include a bioabsorbable material. At least some of the graft material may be external to the intermediate portion. At least some of the graft material may be internal to the intermediate portion. At least some of the graft material may be embedded within the intermediate portion. The graft material may be bonded to at least one of the first end and the second end. The device may be capable of maintaining or configured to maintain fluid flow between a first channel and a second channel, with the first end fixed in the first channel and the second end fixed in the second channel. The first channel may be substantially parallel to the second channel. The intermediate portion may conform to an "S" shape.

[0018] In some embodiments, the device includes a support structure and a graft material. The support structure includes a first end, a second end, and an intermediate portion between the first end and the second end. At least one of the first end, the second end, and the intermediate portion includes cutting struts and at least one of the first end, the second end, and the intermediate portion includes filaments. The graft material is at least bonded to the intermediate portion.

[0019] The first end and the second end include cutting struts and the intermediate portion may include filaments. At least some of the graft material may be external to the intermediate portion. At least some of the graft material may be internal to the intermediate portion. At least some of the graft material may be embedded within the intermediate portion. The graft material may be bonded to at least one of the first end and the second end. The device may be capable of maintaining or configured to maintain fluid flow between a first channel and a second channel, with the first end fixed in the first channel and the second end fixed in the second channel. The first channel may be substantially parallel to the second channel. The intermediate portion conforms to an "S" shape.

[0020] The device can have a diameter between about 1 mm and about 12 mm (e.g., between 2 mm and 6 mm). The device can have a diameter between about 1 mm and about 10 mm (e.g., between 4 mm and 8 mm). The device can have a diameter between about 6 mm and about 25 mm (e.g., between 12 mm and 15 mm). The device can have a diameter between about 20 mm and about 50 mm (e.g., between 35 mm and 40 mm). The device can have a length between about 25 mm and about 150 mm (e.g., between 70 mm and 110 mm). The device can include filaments having a diameter between about 0.001 inches and about 0.01 inches (e.g., between 0.003 inches and 0.006 inches). The device can include struts having a diameter between about 0.001 inches and about 0.01 inches (e.g., between 0.003 inches and 0.006 inches).

[0021] In some embodiments, a device for providing or maintaining a fluid flow through at least one passageway in a human or animal body includes two end portions for securing the device in place and an intermediate portion that enables the end portions to move relative to each other. The end portions and the intermediate portion together define a path for the fluid flow through the device.

[0022] By moving the two end portions relative to each other, the device can respond to movement of one or more passageways in which the device is used. The intermediate portion can be flexible to allow relative movement of the end portions. In some embodiments, the device has varying or different flexibility along the length of the device or along a portion of the length of the device. For example, because the magnitude of the internal stress within the intermediate portion can be relatively low compared to the stress on a support structure (e.g., a stent) having uniform flexibility along its entire length, the device flexibility can reduce the likelihood of device failure due to fatigue.

[0023] The device can be configured to provide or maintain a fluid flow through a single passageway such as an occluded blood vessel. The intermediate portion can be capable of maintaining or configured to maintain a fluid flow between the proximal and distal portions of the occluded blood vessel. The intermediate portion can pass through a further passageway extending between the proximal and distal portions of the blood vessel, such as outside the blood vessel. The device can be configured to function as a bypass between the proximal and distal portions of a single blood vessel such as an artery or a vein.

[0024] The device can be configured to provide a fluid flow from an occluded blood passageway to another passageway. The passageways can be interconnected by an intermediate portion passing through a further passageway extending between the two passageways. The device can be configured to function as a shunt between two passageways such as between an artery and a vein.

[0025] In embodiments where the ends can move relative to each other by means of an intermediate portion, the device can be suitable for use in applications where the ends are fixed in separate channels that move relative to each other. Regardless of the relative movement of the ends, a path for fluid communication is maintained through the device, and the likelihood of fatigue failure of the device due to cyclic movement of the ends can be low compared to a support structure (e.g., a bracket) lacking such an intermediate portion.

[0026] One or both of the ends can expand diametrically to fix the device in place. For example, the expanded end can be expandable to meet with and press against the inner wall of the channel, thereby inhibiting or preventing substantial sliding or rotation of the end within the channel, and / or expanding the channel. For example, the intermediate portion can be diametrically expandable to expand the fluid flow path.

[0027] The device can be in the form of a tube that defines a lumen configured to act as a fluid flow path. In some embodiments, the tube can be liquid-tight to restrict fluid flow within the lumen of the tube. The tube can include, but is not limited to, polymeric materials such as biocompatible polymers like polytetrafluoroethylene (PTFE) or polyurethanes such as polycarbonate aromatic biostable thermoplastic polyurethane elastomers (e.g., ChronoFlex 80A and 55D medical grades, available from AdvanSource Biomaterials of Wilmington, Massachusetts).

[0028] The device can include a support structure that supports the ends. The support structure can support the intermediate portion, in which case the support structure can be flexible within the intermediate portion to allow the ends to move relative to each other.

[0029] When a support structure is provided, the support structure or a portion thereof can be embedded within the wall of the tube. Optionally or additionally, the structure or a portion of the structure can be located on the outside of the tube or within the lumen of the tube.

[0030] The support structure may include at least one mesh. For example, a single mesh may extend along the entire length of the device. In another example, each end of the device includes a mesh, in which case the mesh may stop short of the middle portion or may extend into the middle portion. When a mesh is present in the middle portion, the mesh may have a higher density or a smaller window size in the ends (e.g., a smaller spacing between the fine wires and / or struts of the mesh) than in the middle portion, so that the device is relatively more flexible in the middle portion than in the ends. By the absence of a mesh, or even when including a mesh having a substantially uniform or uniform density or window size (e.g., due to factors other than mesh density or window size), or by including a mesh having a non-uniform density, the device may be relatively more flexible in the middle portion than in the ends.

[0031] The at least one mesh may include biocompatible metal wires. For example, the metal wires may be stainless steel. Optionally or additionally, the at least one mesh may include a shape memory material, such as nitinol and / or cobalt chrome. When a shape memory material is used, at least a portion of the device may be self-expanding.

[0032] One or both ends may include protuberances or barbs configured and / or able to dig into or grip the inner wall of the channel, for example to prevent or reduce sliding or other movement of the end or each end relative to the channel.

[0033] The two ends may have different diameters so that when the channels have different diameters, the device can be manufactured to fit securely within a channel of variable diameter, or one end can be installed in a first channel and the other end in a second channel. The device may be configured for a specific application and / or for a specific patient.

[0034] In some embodiments, a method of diverting fluid flow from a first channel to a second channel (e.g., adjacent the first channel) includes forming a third channel between the first and second channels, providing a device having two ends and a middle portion, deforming the middle portion of the device to allow insertion of the device into the channels, and expanding the ends against the walls of the first and second channels to secure the device in the channels. The middle portion of the device may be bent to allow insertion of the device into the channels. The two ends and the middle portion may be configured to maintain or provide fluid flow through the device.

[0035] One or more ends of the device may be expanded by a balloon catheter. Optionally, or additionally, at least one end may be self-expanding, in which case the method may include providing the device in a retention sleeve and removing the retention sleeve to allow the at least one end to expand.

[0036] The method may further include expanding the intermediate portion to enlarge the third channel, thereby forming a larger path for fluid flow from the first channel to the second channel.

[0037] The methods described herein can be used in a number of surgical procedures and can be performed via minimally invasive (keyhole) techniques. The methods can be particularly suitable for treating coronary artery disease, e.g., by providing a shunt or bypass to divert arterial blood from an occluded coronary artery to a coronary vein (e.g., adjacent to the coronary artery) and / or by crossing an occlusion in a coronary artery by way of an artery leaving the proximal side of the occlusion, extending through subintimal tissue, external tissue, and / or a portion of the proximal vessel, and re-entering the coronary artery distal to the occlusion; suitable for peripheral vascular diseases such as severe limb ischemia, e.g., by providing a shunt or bypass to divert arterial blood from an occluded peripheral artery to a peripheral vein and / or by crossing an occlusion in a peripheral vessel by way of an artery leaving the proximal side of the occlusion, extending through subintimal tissue, external tissue, and / or a portion of the proximal vessel, and re-entering the vessel distal to the occlusion; and / or suitable for non-occluded vessels, e.g., by creating a shunt between a healthy artery and a healthy vein that can be used for dialysis access.

[0038] In some embodiments, a method of treating coronary artery disease includes diverting arterial blood from a coronary artery to a coronary vein by the methods described herein. In some embodiments, a method of treating severe limb ischemia includes diverting arterial blood from a peripheral artery to a peripheral vein by the methods described herein.

[0039] In some embodiments, a method of accessing a target vein includes inserting a needle into the target vein and inserting a guidewire through the needle into the target vein.

[0040] The target vein can be a proximal tibial vein. The method may further include advancing a catheter over a second guidewire. The guidewire may include an ultrasound receiving transducer. The method may further include advancing the guidewire in the direction of blood flow in the target vein. The method may further include inserting a guiding sheath into a second vein upstream of the target vein. The method may further include inserting a second guidewire into the second vein. The second guidewire may include an ultrasound receiving transducer. The method may further include at least one of the following: snaring (capturing) the guidewire with the second guidewire or a snare and snaring the second guidewire with the guidewire, and pulling the second guidewire in a direction opposite to the inflow of blood into the target vein. Snaring the guidewire may include injecting a contrast agent and visualizing using fluoroscopy. The method may further include advancing a catheter over the second guidewire. The catheter may include an ultrasound receiving transducer.

[0041] In some embodiments, a device for treating valvular incompetence includes a proximal portion, a distal portion, and a longitudinal axis between the proximal portion and the distal portion. The distal portion may include at least one blade. The at least one blade may have a retracted position and an expanded position, in which the at least one blade is substantially parallel to the longitudinal axis in the retracted position and the at least one blade is not substantially parallel to the longitudinal axis in the expanded position. The at least one blade may include a sharp surface facing distally and configured to at least partially ablate the valve during advancement of the distal end of the device.

[0042] The at least one blade may include a plurality of blades. The plurality of blades may include three blades. The three blades may be circumferentially spaced apart by approximately 120 degrees. The proximal portion may include a handle configured to operate the at least one blade between the retracted position and the expanded position. The at least one blade may include a shape memory material. The handle may be configured to cause the at least one blade to self-expand from the retracted position to the expanded position. The handle may be configured to longitudinally compress and radially expand the at least one blade from the retracted position to the expanded position. A kit may include the device and a vascular dilatation device. The vascular dilatation device may include at least one of a tourniquet, a balloon, and a LeMaitre device.

[0043] In some embodiments, a method for treating valvular incompetence includes advancing a retrograde valvulotome in a direction opposite to the natural fluid flow in the blood vessel. During advancement of the retrograde valvulotome, at least one blade of the retrograde valvulotome at least partially ablates the valve.

[0044] The retrograde valvulotome may include at least one blade. The at least one blade may have a retracted position and an expanded position, in which the at least one blade is substantially parallel to the longitudinal axis in the retracted position and the at least one blade is not substantially parallel to the longitudinal axis in the expanded position. The at least one blade may include a sharp surface facing distally and configured to at least partially ablate the valve during advancement of the distal end of the device. The at least one blade may include a plurality of blades. The plurality of blades may include three blades. The three blades may be circumferentially spaced apart by approximately 120 degrees. The method may further include dilating the blood vessel and the valve within the blood vessel. Dilating the blood vessel and the valve within the blood vessel may include applying a tourniquet to a body portion containing the blood vessel. Dilating the blood vessel and the valve within the blood vessel may include dilating a balloon within the blood vessel. Dilating the blood vessel and the valve within the blood vessel may include dilating a LeMaitre device within the blood vessel.

[0045] In some embodiments, a method for achieving retrograde perfusion in a first blood vessel includes forming a fistula between the first blood vessel and a second blood vessel and inducing valvular incompetence in the first blood vessel.

[0046] The first blood vessel may include a vein and the second blood vessel may include an artery. Creating valvular insufficiency in the first blood vessel may include inflating a balloon across the valve to a pressure greater than about 10 atmospheres (atm) (about 1,013 kilopascals (kPa)). Creating valvular insufficiency in the first blood vessel may include deploying at least one stent across the valve. Creating valvular insufficiency in the first blood vessel may include inflating a cutting balloon. Creating valvular insufficiency in the first blood vessel may include percutaneous transluminal atherectomy. Creating valvular insufficiency in the first blood vessel may include excising the valve using ultrasound. Creating valvular insufficiency in the first blood vessel may include ablating the valve using a laser. Creating valvular insufficiency in the first blood vessel may include excising the valve using radiofrequency. Creating valvular insufficiency in the first blood vessel may include heating the valve. Creating valvular insufficiency in the first blood vessel may include at least one of advancing and retracting a catheter including a traumatic tip. Creating valvular insufficiency in the first blood vessel may include dilating the blood vessel and the valve within the blood vessel. Dilating the blood vessel and the valve within the blood vessel may include applying a tourniquet to a body part containing the blood vessel. Dilating the blood vessel and the valve within the blood vessel may include dilating a balloon within the blood vessel. Dilating the blood vessel and the valve within the blood vessel may include dilating a LeMaitre device within the blood vessel. Creating valvular insufficiency in the first blood vessel may include dilating the first blood vessel and the valve within the first blood vessel, advancing a guide wire through the blood vessel, and tracking a device over the guide wire. Dilating the first blood vessel and the valve within the first blood vessel may include applying a tourniquet to a body part containing the first blood vessel. Dilating the first blood vessel and the valve within the first blood vessel may include dilating a balloon within the first blood vessel. Dilating the first blood vessel and the valve within the first blood vessel may include dilating a LeMaitre device within the blood vessel. Creating a fistula between an artery and a vein may include accessing the vein. Accessing the vein may include inserting a needle into the vein and inserting a guide wire through the needle into the vein. The vein may be the proximal tibial vein. The method may further include advancing a catheter over a second guide wire. The guide wire may include an ultrasound receiving transducer. The method may further include advancing the guide wire in the direction of blood flow in the vein. The method may further include inserting a guiding sheath into a second vein upstream of the vein. The method may further include inserting a second guide wire into the second vein. The second guide wire may include an ultrasound receiving transducer. The method may further include at least one of: snaring a guide wire with the second guide wire or a snare and snaring the second guide wire with a guide wire, and pulling the second guide wire in a direction opposite to the inflow of blood into the vein. Snaring a guide wire may include injecting a contrast and visualizing using fluoroscopy. The method may further include advancing a catheter over the second guide wire. The catheter may include an ultrasound receiving transducer.Forming a fistula between a first blood vessel and a second blood vessel may include inserting a launching catheter into the second blood vessel, inserting a target catheter into the first blood vessel, emitting an ultrasonic signal from an ultrasonic transmitting transducer, rotating the launching catheter and longitudinally moving at least one of the launching catheters during and until the ultrasonic signal is received by an ultrasonic receiving transducer, and after the ultrasonic signal is received by the ultrasonic receiving transducer, extending a needle from the launching catheter. The launching catheter may include an ultrasonic transmitting transducer and a needle configured to radially extend from the launching catheter. The target catheter may include an ultrasonic receiving transducer. Extending the needle may include exiting the second blood vessel, passing through the interstitial tissue between the second blood vessel and the first blood vessel, and entering the first blood vessel. The ultrasonic transmitting transducer may include a directional transducer. The needle may be configured to radially extend from the launching catheter along a path aligned with the path of the directional transducer. The ultrasonic receiving transducer may include an omnidirectional transducer. Forming a fistula between a first blood vessel and a second blood vessel may include identifying a signal alignment peak on a display device. Identifying a signal alignment peak on a display device may include identifying a color indication that the signal alignment peak is greater than a threshold. Forming a fistula between a first blood vessel and a second blood vessel may include identifying an audible signal indication that the signal alignment is greater than a threshold. Forming a fistula between a first blood vessel and a second blood vessel may include inserting a launching catheter into the second blood vessel. The launching catheter includes a needle configured to radially extend from the launching catheter. Forming a fistula between a first blood vessel and a second blood vessel may further include inserting a target catheter containing a target device into the first blood vessel, expanding the target device, and extending a needle from the launching catheter. Extending the needle may include exiting the second blood vessel, passing through the interstitial tissue between the second blood vessel and the first blood vessel, and entering the first blood vessel, wherein during entering the first blood vessel, the needle pierces the target device. The target device may include a balloon. The balloon may include a polymer and a mesh at least partially embedded in the polymer. Expanding the target device may include inflating the balloon. The target device may include a mesh. Expanding the target device may include distally advancing a proximal portion of the mesh. Expanding the target device may include proximally retracting a distal portion of the mesh. Expanding the target device may include self-expanding the mesh. Forming a fistula between a first blood vessel and a second blood vessel may include inserting a guide wire across the fistula. Forming a fistula between a first blood vessel and a second blood vessel may include enlarging the fistula. Enlarging the fistula may include inflating a balloon. Forming a fistula between a first blood vessel and a second blood vessel may include deploying a prosthesis. After deploying the prosthesis, at least a first portion of the prosthesis may be in the first blood vessel and at least a second portion of the prosthesis may be in the second blood vessel. Deploying the prosthesis may include actuating a trigger handle. The prosthesis may include a stent graft. The stent graft may include a longitudinal portion having a frustoconical longitudinal cross-section. Deploying the prosthesis may include self-expanding the prosthesis. The method may further include expanding the prosthesis using a balloon. The method may further include applying a radiopaque clip to the outside of the skin near the fistula location.The method may further include measuring the distance between the first blood vessel and the second blood vessel.

[0047] In some embodiments, the target catheter for forming the fistula includes a proximal portion and a distal portion. The distal portion may include an expandable member and an ultrasonic receiving transducer adjacent to the expandable member.

[0048] The expandable member may include a balloon. The expandable member may include a mesh. The ultrasonic receiving transducer may include an omnidirectional transducer. The ultrasonic receiving transducer may be radially inward from the expandable member. The catheter may further include an inflation chamber in fluid communication with the expandable member and a proximal portion. The catheter may further include a pressure sensor configured to detect a puncture of the expandable member.

[0049] In some embodiments, a kit for achieving retrograde perfusion in a vein includes a device for disabling a valve and at least one selected from an emitting catheter, a target catheter, and a prosthesis delivery system.

[0050] The device for disabling the valve may include at least one of a reverse valve knife, a balloon, and a stent. The emitting catheter may include a needle configured to extend radially from the emitting catheter. The emitting catheter may include an ultrasonic emitting transducer. The kit further includes a guide wire. The emitting catheter may be configured to advance over the guide wire. The kit may further include an arterial guiding sheath. The kit may further include a second guide wire. The target catheter may be configured to advance over the second guide wire. The target catheter may include an ultrasonic receiving transducer. The ultrasonic emitting transducer may include an omnidirectional transducer. The target catheter may include a balloon. The kit may further include a third guide wire. The second guide wire may be configured to snare the third guide wire. The third guide wire may be configured to snare the second guide wire. The kit may further include a venous guiding sheath. The kit may further include a venous access needle. The kit may further include an access guide wire. The kit may further include at least one balloon. The at least one balloon may be configured to pre - dilate the fistula. The at least one balloon may be configured to dilate the blood vessel diameter. The at least one balloon may be configured to cause valvular insufficiency. The at least one balloon may be configured to apply a pressure greater than about 10 atm (about 1,013 kPa). The kit may further include a prosthesis delivery system. The kit may further include a device configured to stretch a blood vessel. The device configured to stretch a blood vessel may include at least one of a tourniquet, a balloon, and a LeMaitre device. The kit may further include a computing device configured to communicatively connect to at least one of the emitting catheter and the target catheter. The computing device may include a laptop computer. The computing device may include a tablet computer. The computing device may include a smart phone. The computing device may include a display device configured to display information about the relative positions of the emitting catheter and the target catheter. The computing device may include a speaker configured to emit information about the relative positions of the emitting catheter and the target catheter.

[0051] In some embodiments, a method of marking a fistula point includes applying a marker to skin adjacent to a fistula location. The marker may be visible under fluoroscopy.

[0052] The marker may include a clip. The marker may include a radiopaque material. The fistula may be between a first blood vessel and a second blood vessel. Applying the marker may be before deploying a prosthesis in the fistula.

[0053] In some embodiments, a method of causing valvular insufficiency of a blood vessel includes providing a retrograde valvulotome. When advancing the retrograde valvulotome in a direction opposite to the natural fluid flow in the blood vessel, at least one blade of the retrograde valvulotome at least partially excises the valve.

[0054] In some embodiments, a method of achieving retrograde perfusion in a first blood vessel includes providing a first system configured to create a fistula between the first blood vessel and a second blood vessel and providing a second device configured to cause valvular insufficiency in the first blood vessel.

[0055] In some embodiments, a method of forming a fistula in a first blood vessel includes inserting a transmitting catheter into a second blood vessel. The transmitting catheter includes an ultrasonic transmitting transducer and a needle configured to radially extend from the transmitting catheter. The method may further include inserting a target catheter including an ultrasonic receiving transducer into the first blood vessel, emitting an ultrasonic signal from the ultrasonic transmitting transducer, and rotating the transmitting catheter and longitudinally moving at least one of the transmitting catheter during and until the ultrasonic signal can be received by the ultrasonic receiving transducer. The method may further include, after the ultrasonic signal can be received by the ultrasonic receiving transducer, extending the needle from the transmitting catheter. Extending the needle may include exiting the second blood vessel, passing through interstitial tissue between the second blood vessel and the first blood vessel, and entering the first blood vessel.

[0056] The ultrasonic transmitting transducer may include a directional transducer. The needle may be configured to radially extend from the transmitting catheter along a path aligned with the path of the directional transducer. The ultrasonic receiving transducer may include an omnidirectional transducer.

[0057] In some embodiments, a kit for achieving retrograde perfusion in a vein includes a transmitting catheter, a target catheter, and a prosthesis delivery system.

[0058] The transmitting catheter may include a needle configured to radially extend from the transmitting catheter. The transmitting catheter may include an ultrasonic transmitting transducer. The target catheter may include an ultrasonic receiving transducer. The ultrasonic transmitting transducer may include an omnidirectional transducer.

[0059] The methods outlined above and described in further detail below describe certain actions taken by a practitioner; however, it should be understood that they may also include the direction of those actions by another party. Thus, an action such as "causing valvular insufficiency in a first blood vessel" includes "directing the causing of valvular insufficiency in a first blood vessel".

[0060] For purposes of summarizing the invention and the advantages that can be achieved, some objectives and advantages are described herein. Not necessarily all of these objectives and advantages need to be achieved in accordance with any particular embodiment. In some embodiments, the invention may be embodied or practiced in a manner that achieves or optimizes one advantage or a group of advantages without necessarily achieving other objectives or advantages.

[0061] All such embodiments are intended to be within the scope of the invention disclosed herein. With reference to the accompanying drawings, these and other embodiments will be apparent from the following detailed description, and the invention is not limited to any particular disclosed embodiment(s). Optional and / or preferred features described with reference to some embodiments may be combined with and incorporated into other embodiments. All references cited herein, including patents and patent applications, are incorporated by reference in their entirety. Brief Description of the Drawings

[0063] These and other features, aspects, and advantages of the present disclosure are described with reference to the drawings of certain embodiments, which are intended to illustrate certain embodiments and are not intended to limit the invention, where like reference numerals are used for like features, and where:

[0064] Figure 1 Schematically illustrates an exemplary embodiment of a transmitting device that guides a signal from a first body cavity to a target device in a second body cavity.

[0065] Figure 2 is a cross-sectional view along Figure 1 the dashed line B–B.

[0066] Figure 3 Schematically illustrates an exemplary embodiment of a transmitting device.

[0067] Figure 4 Schematically illustrates an exemplary embodiment of a target device.

[0068] Figure 5 Schematically illustrates another exemplary embodiment of a transmitting device.

[0069] Figure 6 Schematically illustrates an exemplary embodiment of a centering device and / or a target device for transmission.

[0070] Figure 7 Schematically illustrates a prosthesis in the proper position after a procedure such as arteriovenous arterialization.

[0071] Figure 8 is a side perspective view of an example embodiment of a device that provides a fluid flow.

[0072] Figure 9 Shows Figure 8 a device that serves as a shunt between two blood vessels.

[0073] Figure 10 is a side perspective view of another example embodiment of a device that provides a fluid flow.

[0074] Figure 11 is a side perspective view of yet another example embodiment of a device that provides a fluid flow.

[0075] Figure 12 is a side perspective view of yet another example embodiment of a device that provides a fluid flow.

[0076] Figure 13 is a side perspective view of yet still another example embodiment of a device that provides a fluid flow.

[0077] Figure 14A is a schematic side cross-sectional view of an example embodiment of an ultrasound-emitting catheter.

[0078] Figure 14B within circle 14B Figure 14A is an enlarged schematic side cross-sectional view of the distal portion of an ultrasound-emitting catheter.

[0079] Figure 15A is a schematic side view of an example embodiment of an ultrasound-targeting catheter.

[0080] Figure 15B within circle 15B Figure 15A is an enlarged schematic side cross-sectional view of an ultrasound-targeting catheter.

[0081] Figure 15C within circle 15C Figure 15A is an enlarged schematic side cross-sectional view of an ultrasound-targeting catheter.

[0082] Figure 16 is an example embodiment of a diagram for detecting catheter alignment.

[0083] Figure 17 is a schematic side view of an example embodiment of a prosthesis delivery system.

[0084] Figure 18 is a schematic side view of an example embodiment of a prosthesis.

[0085] Figure 19 is a schematic side view of another example embodiment of a prosthesis.

[0086] Figures 20A - 20H Schematically illustrates an exemplary embodiment of a method for implementing retrograde perfusion.

[0087] Figure 21 Is a schematic perspective view of an exemplary embodiment of an ultrasonic receiving transducer.

[0088] Figure 22 Is a schematic cross-sectional view of another exemplary embodiment of an ultrasonic receiving transducer.

[0089] Figure 23A Is a schematic perspective view of an exemplary embodiment of a valvulotome.

[0090] Figure 23B Is a schematic perspective view of an exemplary embodiment of a reverse valvulotome.

[0091] Figure 24 Is a schematic perspective view of an exemplary embodiment of a LeMaitre device. Detailed embodiments

[0092] Although certain embodiments and examples are described below, the present invention extends beyond the specifically disclosed embodiments and / or applications and their obvious variations and equivalents. The scope of the invention disclosed herein should not be limited by any of the specific embodiments (s) described below.

[0093] Minimally invasive surgery can provide a means for treating a wider range of patients, including those currently excluded from standard surgical techniques. One such procedure is percutaneous in-situ coronary vein arterialization (PICVA), which is a catheter-based coronary artery bypass procedure in which an occlusion in a diseased artery is "bypassed" by creating a passage between the coronary artery and an adjacent coronary vein. In this way, arterial blood is diverted into the venous system and can perfuse cardiac tissue in a retrograde manner (retrograde perfusion) and restore blood supply to ischemic tissue. Some exemplary devices and methods for performing procedures such as PICVA are described in PCT Publication No. WO 99 / 049793 and U.S. Patent Publication No. 2004 / 0133225, which are hereby incorporated by reference in their entirety.

[0094] The successful performance of minimally invasive procedures that redirect blood flow from a coronary artery to an adjacent vein has heretofore had a low success rate, often due to the inability to properly target the vein from the artery. Without proper systems and methods, these procedures (e.g., attempts to target the vein through a combination of fluoroscopy and an imaging ultrasound probe located at the distal tip of a catheter, such as those described in U.S. Patent Publication No. 2004 / 0133225) are often doomed to failure even before they begin. In fact, such an arrangement can be difficult to navigate, and the positioning of the adjacent vein can require considerable skill on the part of the clinician. In general, improvements in systems and methods for targeting, such as those using the catheters described herein, can enable procedures such as PICVA and transvascular surgeries. Without such improvements, such percutaneous techniques remain secondary compared to traditional open-heart surgeries and other types of bypass surgeries.

[0095] This application, in accordance with several embodiments, describes methods and systems that can be used during minimally invasive surgical procedures that can reduce the performance of traditional surgeries for treating diseases such as coronary artery disease and severe limb ischemia. For example, patients who might otherwise be ineligible for surgery such as coronary artery bypass surgery or peripheral artery bypass surgery can be treated, and the amount of surgical trauma, risk of infection, and / or recovery time can be reduced or significantly reduced compared to traditional surgeries.

[0096] Figure 1 An example embodiment of a transmitting device 10 that schematically illustrates the transmission of a guiding signal from a first body cavity 30 to a target device 20 in a second body cavity 35 is depicted. The transmitting device 10 includes a signal transmitter 12. The transmitting device 10 can include, for example, a catheter that includes an elongated flexible shaft portion and a tip portion, and can provide a conduit for administering treatment within a patient's body. The transmitting device 10 can be adapted to be positioned and moved through a first cavity or vessel 30 within a patient's body (e.g., a ventricle, coronary artery, coronary vein, peripheral artery, peripheral vein). The elongated portion of the transmitting device 10 includes an outer sheath 11 that encloses a space, which defines a lumen 13. The space within the lumen 13 can be appropriately partitioned or subdivided as needed to define passages for administering treatment, controlling the positioning of the transmitting device 10, etc. Such subdivision can be achieved, for example, longitudinally or concentrically in an axial manner.

[0097] The transmitting device 10 includes a signal transducer 12. The signal transducer 12 is configured to provide or transmit a signal 40 that is guided outward from the transmitting device 10. In Figure 1In the illustrated embodiment, the signal 40 is directed radially outward from the transmitting device 10 in a direction perpendicular to the longitudinal axis of the transmitting device 10. As mentioned in more detail below, in some embodiments, the direction of the signal 40 need not be perpendicular to the longitudinal axis of the transmitting device 10 and may be directed at an angle to the longitudinal axis of the transmitting device 10. The signal transducer 12 may thus form at least a part of the signal generating means.

[0098] The signal transducer 12 is connected to a signal transmitter 50. The signal transmitter 50 may be suitably selected from ultrasonic or suitable electromagnetic sources such as lasers, microwave radiation, radio waves, etc. In some embodiments, as described in further detail below, the signal transmitter 50 is configured to generate an ultrasonic signal which is forwarded to the signal transducer 12 which in turn directs the signal 40 out of the first body cavity 30 into the surrounding tissue.

[0099] The target device 20 is located within a neighboring second body cavity or blood vessel 32 (e.g., ventricle, coronary artery, coronary vein, peripheral artery, peripheral vein) within the patient's body. The first and second body cavities 30, 32 are separated by intervening tissue 34 - which is sometimes referred to as interstitial tissue or septum. The first and second body cavities 30, 32 are close to each other in a parallel manner for at least a portion of their respective lengths. For example, many veins and arteries in the body are known to travel parallel to each other for at least a portion of their total lengths.

[0100] The target device 20 may adopt an arrangement similar to that of the generating device 10. For example, the target device 20 may include a catheter comprising an elongate flexible rod-shaped portion and a tip portion. For another example, fine movement and positioning of the target device 20 within the body cavity 32 may be achieved. For yet another example, the target device 20 may include an outer sheath 21 enclosing a space-defining cavity 23. The cavity 23 may be suitably partitioned, for example, in the same manner as the transmitting device 10.

[0101] The target device 20 includes a receiving transducer 22 configured to receive the signal 40 from the transducer 12 of the transmitting device 10. The receiving transducer 22 forms at least a part of the signal detecting means. In use, when the receiving transducer 22 receives the signal 40 transmitted from the signal transducer 12, the receiving transducer 22 sends 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 audio display (e.g., beep or emit some other sound upon receipt of the signal), etc.

[0102] In this manner, the transmission and detection of the guided signal 40 can permit the orientation and positioning of the transmitting device 10 relative to the target device 20. In use, the transmitting device 10 and the target device 20 can be manipulated by a user of the system until the output display 61 indicates that the signal 40 is being received by the target device 40.

[0103] In some embodiments, the signal 40 comprises or is an ultrasonic signal. The signal 40 is directional and is transmitted by the signal transducer 12 in the shape of a narrow cone or arc (e.g., the width of the signal band increases as the distance from the signal transducer 12 increases). Thus, the alignment accuracy between the transmitting device 10 and the target device 20 depends not only on signal detection but also on the distance between the two devices - because the signal beam width is larger at greater distances. This level of error is referred to as "positional uncertainty". For positional uncertainty, there may be a certain level of tolerance; however, if the treatment is to be precisely guided, the amount of uncertainty should be reduced or minimized. For example, if the diameter d of the signal transducer 12 is 1 mm and the frequency of the ultrasonic signal is 30 MHz, the positional uncertainty x (e.g., the error magnitude on either side of the centerline) is 1 mm at a 5 mm vertical separation between the transmitting device 10 and the target device 20. For clinical applications, the positional uncertainty generally should not exceed approximately ±5 mm (for a total signal beam width of 10 mm at the receiving point). In some embodiments, the positional uncertainty is between approximately ±0.01 mm and approximately ±4.50 mm or between approximately ±0.1 mm and approximately ±2 mm. In some embodiments, the positional uncertainty does not exceed approximately ±1 mm.

[0104] The intensity of the signal 40 can be a factor in detection, and the signal intensity generally decreases as the distance between the transmitting device 10 and the target 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 ultrasonic signal, a significant decay of the signal can be expected when the transmitting device 10 and the target device 20 are separated by more than approximately 20 mm of solid tissue (e.g., intervening tissue 34). The density of the intervening tissue 34 can also have an effect on the decay of the signal 40 relative to the distance (e.g., denser tissue causes more signal decay compared to less dense tissue).

[0105] The frequency of the ultrasonic signal can also affect the thickness of the signal transducer, which is 0.075 mm at 30 MHz for a standard ultrasonic ceramic transducer (e.g., a piezoelectric transducer (PZT)).

[0106] Figure 2 is along Figure 1Cross-sectional view along the dashed line B–B. The correct orientation of the emitting device relative to the target device can be a factor in detection because the orientation line 41 can determine where the treatment will be applied. If the orientation signal 40 is associated with the device for delivering the treatment (e.g., offset parallel and longitudinally), the clinical need for precise placement of the treatment in the patient can be better served. For example, in this way, the user of the system can apply the treatment to the correct location by ensuring that the emitting device 10 and the target device 20 are correctly positioned via the transmission and reception of the signal 40. Figure 2 In the orientation line 41 not only indicates the direction in which the signal travels but also the path along which the treatment can be applied to the patient.

[0107] Figure 3 Schematically illustrates an example embodiment of the emitting device 10. The emitting device 10 includes a signal transducer 120 oriented at an oblique angle relative to the longitudinal axis of the emitting device 10. When the emitting device enters the body cavity 30, the signal 40 is transmitted at an angle with respect to the direction of travel (e.g., forward travel, lateral travel) of the emitting device 10 ( Figure 1 and 2 ). In some embodiments, the beam angle is approximately perpendicular to the longitudinal axis of the emitting device 10. In some embodiments, when 0° corresponds to the longitudinal axis of the emitting device 10 in the direction of travel, the beam angle is between approximately 20° and approximately 60° with respect to the perpendicular, between approximately 30° and approximately 50° with respect to the perpendicular, or approximately 45° with respect to the perpendicular.

[0108] The emitting device 10 includes a hollow needle or cannula 17, which is an example device for applying the treatment. During the travel of the emitting device 10, the hollow needle 17 is located within the cavity 13 of the emitting device 10 in an undeployed or retracted state. The hollow needle 17 can be deployed / extended from the emitting device 10 via a hole 16 in the outer sheath 11 at a time deemed appropriate by the user (e.g., after the signal 40 has been detected by the target device 20). The hole 16 can allow fluid communication between the cavity 13 and the body cavity 30 ( Figure 1 ). As Figure 3 illustrated in the example embodiment, the hollow needle 17 can travel along a path parallel to the direction of the signal 40. The hollow needle 17 can be used to pierce the intervening tissue 34 ( Figure 1 ). In some embodiments, the hollow needle 17 effects the overall transport through the intervening tissue 34 and in so doing causes the emitting device 10 to enter a second body cavity 32 ( Figure 2 ). If desired, the path through the intervening tissue 34 created by the hollow needle 17 can subsequently be widened to allow fluid communication between the first body cavity 30 and the second body cavity 32.

[0109] Treatment devices suitable for use in several embodiments may include, for example, devices and / or instruments selected from the following: cannulas, lasers, radiation-emitting devices, probes, drills, blades, wires, needles, suitable combinations thereof, and the like.

[0110] In some embodiments, the hollow needle 17 includes a sensor 19 that can help further determine the position information of the tip of the hollow needle 17 relative to the emitting device 10. In some embodiments, the sensor 19 is configured to detect changes in hydrostatic pressure. Other sensors suitable for use in the systems and methods described herein may include temperature sensors, oxygenation sensors, and / or color sensors.

[0111] Optionally, the hollow needle 17 may include an additional signal transducer 122. In Figure 3 the embodiment shown, the signal transducer 122 is located near the tip of the hollow needle 17 on the end of the guide wire 14. If desired, the signal transducer 122 may also or alternatively be located on the hollow needle 17. In use, the signal transducer 122 is driven with short transmit pulses that generate both directed and non-directed signal pulses. The signal pulses can be detected by a receiving transducer 22 mounted on the target device 20. The distance from the guide wire 14 or the hollow needle 17 to the receiving transducer 22 and thus to the target device 20 can be determined at least in part by the time based on the delay between the transmission of the signal pulse from the signal transducer 122 and the reception of the signal pulse on the receiving transducer 22.

[0112] Figure 4 Schematically illustrates an example embodiment of the target device 20. In Figure 4 the embodiment shown, the target device 20 is located within the body cavity 32. As mentioned above, the target device 20 includes a receiving transducer 22 for receiving the signal 40. The receiving transducer 22 can be unidirectional (e.g., only capable of receiving or configured to receive signals from one direction) or omnidirectional (e.g., capable of receiving or configured to receive signals from any direction). Arrow A shows the reverse direction of blood flow after arteriovenous arteriovenous fistula (also known as PICVA) has been achieved. The target device 20 includes an omnidirectional ultrasonic signal receiving transducer 60. An optional reflecting cone 601 can direct the signal 40 onto the disk-shaped receiving transducer 60. The acoustic window 602 can separate the reflecting cone 601 from the receiving transducer 60. In some embodiments, the omnidirectional ultrasonic signal receiving transducer can be obtained by positioning a flexible piezoelectric material such as a cylinder of polyvinylidene fluoride (PVDF) around the outer sheath of the target device 20. Thus, the cylinder can function in a manner similar or equivalent to the receiving transducer 60.

[0113] In Figure 4In the illustrated embodiments, the target device 20 includes an optional passageway 25 for administering an agent, such as a therapeutic agent, to a patient. In some embodiments, the passageway 25 functions as a conduit to permit the use of a blocking material 251 for at least partially occluding or blocking a body cavity 32. The blocking material 251 may be suitably selected from gel-based materials. The blocking material 251 may also or alternatively include an embolic forming member (e.g., a balloon, a self-expanding stent, etc.). The placement of the blocking material 251 may be guided by moving the target device 20. The presence of a guiding member 24 within the lumen 23 of the target device 20 permits the user to precisely manipulate the position of the target device 20 as desired.

[0114] Referring again to Figure 2 , the transmitting device 10 includes a signal transducer 12 that may optionally be oriented so that the signal 40 is transmitted at an angle non-perpendicular to the signal transducer 12. Figure 5 Schematically illustrates another exemplary embodiment of the transmitting device 10. In some embodiments, such as the transmitting device 10 shown in Figure 5 , the signal transducer is in the form of a signal transducer array 123. The signal transducer array 123 includes a plurality of signal transducer elements 124 that may be collectively oriented to at least partially define the signal beam width and the angle relative to the transmitting device 10. The smaller size of the elements 124 may enable the signal transducer 123 not to occupy a significant proportion of the lumen 13 of the transmitting device 10.

[0115] Figure 5 The embodiment shown in may be used for ultrasonic beam forming signals. Figure 5 Shows an array of signal transducer elements 124 respectively connected to a transmitter 50 via delay elements 51 that cause the signals to each element 124 to be delayed relative to one another. The delay elements may provide or ensure that the ultrasonic wave fronts from each element 124 are aligned to produce a beam of ultrasound 40 at a desired angle. For example, in some embodiments in which the signal 40 includes visible light, an array of LEDs may also or alternatively be used.

[0116] Figure 6 Schematically illustrates an exemplary embodiment of a centering device and / or target devices 10, 20 for transmission. To assist in the alignment process between the transmitting device 10 in the first body cavity 30 and the target device 20 in the second body cavity 32, one or both of the devices 10, 20 may include means for centering the respective devices within their body cavities.

[0117] In some embodiments, the centering device includes an inflatable bladder or balloon 111 that is located within lumens 13, 23 in an undeployed state and can be inflated when the devices 10, 20 reach a desired location within the patient. The balloon 111 can be disposed on the outer surface of the outer sheath 11, 21. The balloon 111 is in an annular shape such that it at least partially surrounds the devices 10, 20 in a toroidal or doughnut-like manner. The balloon 111 can be arranged such that it inflates on only one side or only two opposite sides of the devices 10, 20. As Figure 6 illustrated, the balloon 111 is deployed on one side of the delivery device 10.

[0118] In some embodiments, the centering device includes one or more ring structures 112 in an undeployed or retracted state that are located within recesses formed within lumens 13, 23 or within the outer sheath 11, 21. When the devices 10, 20 reach a desired location within the patient, the one or more ring structures 112 can expand radially outwardly from the devices 10, 20, thereby centering the devices 10, 20 within the body cavities 30, 32. The outward expansion of the ring structures 112 can be suitably achieved by the length of a compression wire—such as causing it to bow outwardly from the outer sheath 11, 21. A centering device employing this configuration can include a plurality of compressible lengths of wire or other suitable flexible material arranged in parallel with a radial space therearound at the edge of the outer sheath 11, 21. Compression of the plurality of wires can be caused via proximal and / or distal sliding members (not shown) located near the ends of the plurality of wires. The sliding members are capable of translational movement along the longitudinal axis of the devices 10, 20. As Figure 6 illustrated, the target device 20 includes a fully deployed centering device 112 that centers the target device 20 within the body cavity 32.

[0119] Other possible devices for centering the devices 10, 20 within the body cavities 30, 32 include, but are not limited to, expandable Chinese lantern devices, reversibly expandable stents, coils, helices, retractable probes or legs, combinations thereof, and the like.

[0120] In some embodiments, a centering device or other device (e.g., a balloon, a stand-off of different lengths, etc.) can be used to orient devices 10, 20 within body cavities 30, 32 rather than at or substantially at the center of the body cavity. For example, device 10 can be oriented near the wall of body cavity 30 where the needle 17 will exit the body cavity 30, which can provide a shorter ultrasound signal path and / or reduce error, for example, due to the needle 17 passing through the space within the lumen. For another example, device 10 can be oriented near the wall of body cavity 30 opposite the wall of body cavity 30 where the needle 17 will exit the body cavity 30, which can provide, for example, a rigid surface against which the needle 17 can push. For yet another example, device 20 can be oriented near the wall of body cavity 32 where the needle 17 will enter the body cavity 32, which can provide, for example, a shorter ultrasound signal path. Other device orientations that are not centered and not near the vessel wall are also possible (e.g., some fraction of a diameter away from the wall and / or center of the cavity, such as 1 / 2, 1 / 3, 1 / 4, etc.).

[0121] Examples

[0122] The methods and systems described herein illustrate specific applications in cardiovascular surgery according to several embodiments. Certain aspects are further illustrated by the following non-limiting examples, in which the system is used by a clinician to perform the procedure of percutaneous arterial venous connection (PICVA), thereby enabling retrograde perfusion of cardiac tissue after occlusion of the coronary artery.

[0123] The emitting device 10 is inserted into the occluded coronary artery by standard keyhole surgery techniques (e.g., advancing over a guidewire, advancing through a guiding catheter). The target catheter 20 is inserted into the coronary vein that travels parallel to the coronary artery by standard keyhole surgery techniques (e.g., advancing over a guidewire, advancing through a guiding catheter). The coronary vein is not occluded and, therefore, provides an alternative pathway for blood flow to the myocardium, effectively bypassing the occlusion in the coronary artery.

[0124] The emission catheter 10 includes a PZT ultrasonic transducer 12 (e.g., CTS Piezoelectric Products available from Albuquerque, New Mexico) oriented such that in this embodiment the ultrasonic beam is oriented at a 45° angle (relative to the longitudinal axis of the emission device), preferably in the direction of blood flow in the artery 30, but other angles up to about 90° are possible. The ultrasonic transducer 12 is activated and in this embodiment an ultrasonic signal 40 of 30 MHz is transmitted from the emission catheter 10, but other frequencies are possible. The target catheter 20 includes an omnidirectional ultrasonic receiving transducer 60. To assist in positioning both the emission catheter 10 and the target catheter 20, both catheters 10, 20 include centering or orienting means, in this embodiment in the form of an annular inflatable balloon 111, but other centering or orienting means or their absence are possible. When the emission catheter 10 is considered to be in a suitable position near the occlusion site within the coronary artery 30, the centering means 111 on the emission catheter 10 is deployed by the clinician. This can be determined via standard fluoroscopic imaging techniques and / or based on physical resistance. The target catheter 20 is then moved within the adjacent coronary vein 32 until the guided ultrasonic signal 40 is detected by the signal receiving transducer 60. To achieve a more precise alignment between the emission 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.

[0125] After receiving the transmitted signal 40, the clinician can determine that both the emission catheter 10 and the target catheter 20 are rotationally and longitudinally correctly positioned within their respective blood vessels 30, 32 to allow the start of the arteriovenous connection procedure. The target catheter 20 can be used to occlude blood flow within the coronary vein 32 by administering a gel occlusion material 251 via a passage 25 in the target catheter 20. The occlusion material 251 can be administered at a downstream position within the coronary vein 32 relative to the position of the receiving signal transducer 60 based on venous blood flow.

[0126] The clinician can then initiate a veno-arterial connection by deploying the hollow needle 17 from the delivery catheter 10 substantially along a path that is parallel to and close to the path taken by the ultrasound signal 40 through the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, or the hollow needle 17 can cross a path that intersects the ultrasound signal path at a point within the coronary vein 32. The hollow needle 17 optionally includes a sensor 19 near its tip that is configured to detect changes in hydrostatic pressure or Doppler flow such that as the hollow needle 17 passes between the two blood vessels 30, 32, the user can monitor the transition from arterial pressure to venous pressure. Optionally, the hollow needle 17 includes a guidewire 14 within the lumen or bore of the hollow needle 17 during deployment. Once the hollow needle 17 and the guidewire 14 have passed through the intervening tissue 34, the hollow needle 17 can be retracted into the lumen 13 of the delivery catheter 10, leaving the guidewire 14 in place. In some embodiments, once the hollow needle 17 has passed through the intervening tissue 34, the user can separately pass the guidewire 14 through the lumen or bore of the hollow needle 17 and then retract the needle 17 into the delivery catheter 10.

[0127] The clinician withdraws the delivery catheter 10 from the patient, leaving the guidewire 14 in place. A further catheter device is then slid along the guidewire 14. Figure 7 Schematically illustrates a prosthesis 26 such as an expandable stent 26 in place after a procedure such as arteriovenous arterialization. Further details regarding possible prostheses including stents and stent-grafts are provided below. The stent 26 can be deployed to widen a perforation in the intervening tissue 34 between the coronary artery 30 and the coronary vein 32, where the interrupted arrow A indicates the direction of blood flow through the stent 26 between the first and second body cavities 30, 32 (e.g., arterial blood is thus diverted into the venous system and can retrograde perfuse myocardial tissue). The stent 26 can occlude upward flow in the cavity 32, forcing blood flow in the cavity 32 to be in the same direction as the blood flow in the cavity 30. The graft material of the stent 26 can form a fluid-tight cavity between the cavities 30 and 32. The target catheter 20 is withdrawn from the patient, leaving the occluding material 251 in place. Optionally, further occlusion or suturing can be inserted into the coronary vein to inhibit or prevent reversal of arterial blood flow, as described in further detail herein.

[0128] Although the specific examples described above relate to cardiovascular surgery, the methods and systems described herein can have far-reaching applications in other forms of surgery. For example, any surgery involving the need to direct a treatment from one body cavity (e.g., for treating peripheral arterial disease) towards another adjacent body cavity can be considered. Thus, applications in the fields of neurosurgery, urology, and general vascular surgery are also possible. Treatments of this type are not limited to creating a passageway between body cavities. For example, the methods and systems described herein can also be used in guiding techniques such as catheter ablation, non-contact mapping of the ventricles, delivering drugs to precise regions of the body, and the like.

[0129] Certain techniques for effectively bypassing an occlusion in an artery via a percutaneous procedure have been described above. These techniques include establishing a passageway or channel between a first channel and a second channel adjacent to the first channel to interconnect the first channel and the second channel via a third channel, where the first channel can be, for example, an artery, vein, or ventricle upstream of the occlusion, and the second channel can be an artery, vein, or ventricle. A fluid such as blood can be diverted from the first channel to the second channel via the interconnecting third channel. In embodiments where the first channel includes an artery and the second channel includes a vein, arterial blood can be perfused into the tissue in a retrograde manner (retrograde perfusion).

[0130] As described above, an interconnecting channel between a first body channel and a second body channel can be established, for example, by deploying a needle from a first catheter located within the first channel such that the needle traverses the interstitial tissue or septum between the first channel and the second channel. A second catheter can be located within the second channel to provide a target device for receiving signals, such as ultrasonic 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, thereby ensuring that the needle is deployed in the correct position and orientation to create a channel for fluid flow between the first channel and the second channel.

[0131] To provide or maintain blood flow through the interconnecting channel or passageway, a structure containing a lumen can be inserted into the channel to support the interstitial tissue and / or to inhibit or prevent closure of the channel. For example, as described herein, a tube can include a stent that is expanded in the passageway using a balloon catheter or self-expanding. A catheter for delivering such a structure, such as a balloon catheter or a catheter allowing self-expansion, can be guided to the passageway via a guide wire deployed in the channel by the first catheter.

[0132] As the heart beats, passageways such as arteries, veins, and ventricles can pulsate, for example due to movement of the heart wall, movement of the peripheral limbs, and / or fluctuations in pressure within the passageways themselves. Such pulsations can cause movement of the passageways relative to one another, which can impose stresses on structures within the interconnecting passageways therebetween. Such stresses can be greater compared to the stresses experienced by structures within a single passageway. The stresses can cause premature failure of the structures, for example by fatigue failure of stent struts. Failure of the structures can lead to damage to interstitial tissue and / or occlusion of the interconnecting passageways, which can result in significant complications or complete failure of treatment.

[0133] Figure 8 Illustrated is a device or implant or prosthesis 100 for providing or maintaining fluid flow through at least one passageway. Device 100 includes a first or proximal portion 102, a second or distal portion 104, and an intermediate portion 106 between proximal portion 102 and distal portion 104. The device includes a bore or lumen 110 for passage of fluid through the device 100. Device 100, for example at least the intermediate portion 106 of device 100, includes a flexible polymeric tube 108. Flexible polymeric tube 108 can at least partially define lumen 110.

[0134] Device 100 includes 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 in the outer wall of tube 108 near the proximal portion 102 of device 100. In some embodiments, at least a portion of mesh 114, such as wires or struts, is embedded in the outer wall of tube 108 near the distal portion 104 of device 110. Meshes 112, 114 can include biocompatible metals such as stainless steel and / or shape memory materials such as nitinol or cobalt chromium.

[0135] Wire meshes 112, 114 can stiffen ends 102, 104, respectively. In some embodiments in which the intermediate portion 106 does not include a mesh, the intermediate portion 106 can be relatively flexible compared to ends 102, 104, and / or ends 102, 104 can have relatively high radial rigidity.

[0136] In some embodiments, the ends 102, 104 of the device 100 are diametrically expandable. For example, the wire meshes 112, 114 may have a smaller diameter after being formed or manufactured as compared to the channel, such as a blood vessel, in which the device 100 will be deployed. When the device 100 is in a suitable position within the channel, the ends 102, 104 can expand or deform outwardly so that the respective diameters of the ends 102, 104 increase, for example to abut the inner sidewalls of the channel. The ends 102, 104 are configured to maintain the expanded diameter indefinitely, for example by plastic deformation of the material (e.g., wires, struts) of the meshes 112, 114 and / or by providing a locking mechanism arranged to mechanically lock the meshes 112, 114 in the expanded position. The intermediate portion 106 of the device 100 may be diametrically expandable, for example via plastic deformation of the tube 108.

[0137] Figure 9 Show Figure 8 The device 100, which is deployed to provide a fluid flow path between a first channel 116 and a second channel 118. The channels 116, 118 may include coronary blood vessels, such as the coronary artery 116 and the coronary vein 118, or vice versa. The channels 116, 118 may include peripheral blood vessels (e.g., blood vessels in the extremities), such as the femoral artery or other peripheral arteries 116 and the femoral vein or other peripheral veins 118, or vice versa. The ends 102, 104 and the intermediate portion 106 of the device 100 have been expanded to contact and push against the inner walls of the channels 116, 118. The distal portion 104 of the device 100 is located within the second channel 118, and the proximal portion 102 of the device 100 is located within the first channel 116. The intermediate portion 106 extends through an opening surgically formed between the channels 116, 118 or an interconnecting channel 130.

[0138] The expanded ends 102, 104 of the device 100 are resilient and impart an outward radial force on the inner walls of the channels 116, 118. Due to the radial rigidity of the ends 102, 104 of the device 100, the ends 102, 104 remain or are fixed in their respective proper positions within the channels 116, 118. The sliding of the device 100 within the channels 116, 118 is thus prevented or reduced. In this way, the ends 102, 104 of the device 100 can fix or mount the device 100 in place, during use, while providing or maintaining fluid flow ( Figure 8 ) through the lumen 110 of the tube 108. In this way, the device 100 can act as a shunt between the first channel 116 and the second channel 118.

[0139] 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 the combination of the first channel 116, the second channel 118, and the interconnecting channel 130( Figure 9 ). In response to relative movement of the channels 116, 118, the flexible middle portion 106 can cause the end portions 102, 104 of the device 100 to move relative to each other.

[0140] In embodiments where the middle portion 106 does not include a wire mesh but includes a flexible polymeric material tube 108, the middle portion 106 may not be prone to damage due to, for example, mesh fatigue caused by cyclic or other stresses imparted by relative movement through the channels 116, 118.

[0141] The middle portion 106 of the device 100 has sufficient elasticity to maintain the expansion of the interconnecting channel 130 so that the interconnecting channel 130 remains open to provide or maintain a blood flow path from the artery 116 to the vein 118 via the lumen 110 of the tube 108( Figure 8 ). Blood flow from the artery 116 to the vein 118 via the interconnecting channel 130 can thus 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 channel 130 to provide a path for fluid communication through the device 100.

[0142] The proximal portion 102 and the distal portion 104 of the device 100 are arranged such that, when the device 100 is deployed with the distal portion 104 in the vein 118 and the proximal portion 102 in the artery 116, for example as Figure 9 shown, the diameter of the expanded distal portion 104 is sufficient to hold the distal portion 104 within the vein 118, and the diameter of the expanded proximal portion 102 is sufficient to hold the proximal portion 102 within the artery 116. The diameter of the proximal portion 102 can thus be different from the diameter of the distal portion 104. By selecting suitable diameters for the end portions 102, 104, and the middle portion 106, the device 100 can be customized for certain anatomical structures and / or the anatomical structure of an individual patient.

[0143] An example process for positioning Figure 8 the device 100 to provide a shunt between an occluded artery 116 and vein 118 (e.g., a coronary artery 116 and a coronary vein 118, or a peripheral artery 116 and a peripheral vein 118) to effect retrograde perfusion of arterial blood will now be described, for example as Figure 9 shown.

[0144] A catheter can be inserted into a patient's arterial system via a small hole typically cut in the patient's groin area. The catheter is supplied to artery 116 and directed to a location upstream of the occlusion site, such as at a site near and parallel or substantially parallel to vein 118. A hollow needle is deployed from the catheter, through the wall of artery 116, through the interstitial tissue 132 separating artery 116 and vein 118, and through the wall of vein 118. The path of the needle creates an interconnecting channel or opening 130 that permits blood to flow between artery 116 and vein 118. Deployment of the needle can be directed by a transmitter (e.g., a directional ultrasound transmitter) connected to the catheter in artery 116 and a receiver (e.g., an omnidirectional ultrasound receiver) connected to the catheter in vein 118, or vice versa, such as described herein and in U.S. Patent Application No. 11 / 662,128. Other methods of forming opening 130 are possible (e.g., with or without directional ultrasound guidance, using other types of guidance such as described herein, from vein to artery, etc.).

[0145] Before the needle is withdrawn from channel 130, a guide wire (e.g., such as the guide wire 14 described with respect to Figure 3 is inserted through the hollow needle and into vein 118. The needle is then retracted, leaving the guide wire in place in artery 116, channel 130, and vein 118. The catheter carrying the needle can then be withdrawn from the patient's body. The guide wire can be used to direct further catheters to the interconnecting channel 130 between artery 116 and vein 118.

[0146] A catheter carrying device 100 in a non-expanded state is advanced toward interconnecting channel 130, directed by the guide wire, such as by a rapid exchange lumen or through lumen 110. For example, the catheter can include a balloon catheter configured to expand at least a portion of device 100 and / or a catheter configured to permit at least a portion of device 100 to self-expand. The distal portion 104 of device 100 passes through interconnecting channel 130 and into vein 118, leaving the proximal portion 102 in artery 116. The intermediate portion 106 of device 100 is at least partially within channel 130 and at least partially within artery 116 and vein 118. The intermediate portion 106 bends to assume a curved or "S" - shaped configuration, depending on the anatomy of the site. Adopting such a curvature enables the shape of the intermediate portion 106 extending through interconnecting channel 130 and optionally into at least one of channels 116, 118 to conform to the shape of at least interconnecting channel 130.

[0147] For example, the distal portion 104 of the device 100 expands after balloon inflation or by self-expansion, thereby increasing the diameter of the distal portion 104 and fixing the distal portion 104 against the inner wall of the vein 118. The catheter may be adapted to expand the intermediate portion 106 of the device 100 - for example, by balloon inflation - so that the interconnecting channel 130 can be widened or enlarged to obtain blood flow (e.g., sufficient blood flow) from the artery 116 to the vein 118. For example, the proximal portion 102 of the device 100 expands after balloon inflation or by self-expansion, thereby increasing the diameter of the proximal portion 102 and fixing the proximal portion 102 against the inner wall of the artery 116.

[0148] After the ends 102, 104 of the device 100 expand, for example, due to self-expansion and / or balloon inflation, and with or without improved expansion after deployment, the catheter and guidewire are withdrawn from the patient's body. In this way, the device 100 is fixed or mounted in place within the vein 118, artery 116, and interconnecting channel 130, as Figure 9 shown. In embodiments in which the device 100 includes a stent graft, the graft that can form a fluid-tight channel between the artery 116 and the vein 118 may inhibit or prevent antegrade blood flow in the vein 118 because such a channel is blocked, which can exclude or replace the occluding agent in the vein 118.

[0149] The catheter can be adapted to selectively dilate, either alone or in combination, the proximal portion 102, the distal portion 104, and / or the intermediate portion 106 of the device 100, for example, by providing two or more separately inflatable balloons or balloon portions, a single balloon configured to simultaneously dilate all portions of the device 100, or a single balloon configured to dilate one or more selected portions of the device 100. For example, the ends 102, 104 can be self-expanding, and the intermediate portion 106 can be dilated by a balloon to enlarge the passageway 130. In some embodiments including balloon dilation, all or selected portions of the device 100 can be simultaneously dilated, for example, by a balloon extending through the entire length of the device 100 or by multiple balloons longitudinally spaced to selectively inflate selected portions of the device 100, and / or by successive dilation of a balloon or multiple balloons. In some embodiments including at least partial self-expansion, all or selected portions of the device 100 can be dilated, for example, by proximal retraction of a sheath over or around the device 100, which can cause the device 100 to deploy from the distal end to the proximal end as the sheath is proximally retracted. It is also possible for the device 100 to deploy from the proximal end to the distal end and for the device 100 to deploy first in the middle and then at both ends. In some embodiments, for example, in embodiments where the device 100 is at least partially conical or tapered, a conical or tapered balloon can be used to at least partially dilate the device 100. In certain such embodiments, the portion of the balloon closer to the vein 118 can have a larger diameter than the portion of the balloon closer to the artery 116, such that the device 100 can be adapted to a changed vein diameter due to any increase in pressure or blood flow in the vein 118.

[0150] Other steps can be included in the process. For example, prior to deployment of the device 100, the balloon catheter can be directed to and positioned within the interconnecting passageway 130 such that the inflatable balloon portion of the catheter is located within the interconnecting passageway 130. After balloon inflation, the balloon pushes against the walls of the interconnecting passageway 130 to widen or enlarge the interconnecting passageway 130 to facilitate subsequent insertion of the device 100.

[0151] Figure 10 Another device 134 is illustrated that provides fluid flow through at least one channel. The device 134 includes a mesh 136 and a polymeric tube 108. The mesh 136 is shown outside the polymeric tube 108, but as described herein, it can also or alternatively be on the inside of the polymeric tube and / or within the polymeric tube 108. As described with respect to the device 100, the device 134 includes a proximal portion 102, a distal portion 104, and an intermediate portion 106. In Figure 10 the illustrated embodiment, the mesh 136 extends along the entire length of the device 134 including along the intermediate portion 106.

[0152] In some embodiments, the spacing of the filaments or struts of the mesh 136 changes along the length of the device 134. For example, the winding density of a woven or laminated filamentous mesh can change and / or the window size pattern of a cut mesh can change.

[0153] In some embodiments, the spacing can be relatively small in the proximal portion 102 and the distal portion 104, and the spacing can be relatively large in the intermediate portion 106. In other words, the density and window size of the mesh 136 can be relatively low in the intermediate portion 106, and the density and window size of the mesh 136 can be relatively high at the ends 102, 104. In certain such embodiments, the intermediate portion 106 can be flexible compared to the ends 102, 104. The relatively rigid ends 102, 104 can be engaged and fixed in the channel. Although the mesh 136 in the intermediate portion 106 can be subjected to stresses such as cyclic stresses, in use, the relatively high flexibility of the intermediate portion 106 due to the low density or window size results in a lower impact of the stress because the intermediate portion can bend in response to the stress. The risk of fatigue failure of the device 134 and specifically the filaments or struts 138 of the mesh 136 can thus be reduced compared to a device having uniform flexibility along its entire length.

[0154] In some embodiments, the spacing can be relatively large in the proximal portion 102 and the distal portion 104, and the spacing can be relatively small in the intermediate portion 106. In other words, the density of the mesh 136 can be relatively high in the intermediate portion 106 (or the window size of the mesh 136 can be relatively small), and the density of the mesh 136 can be relatively low at the ends 102, 104 (or the window size of the mesh 136 can be relatively large). In certain such embodiments, the intermediate portion 106 can have a radial strength sufficient to inhibit or prevent collapse of the channel 130, yet still be flexible enough to bend in response to stresses such as cyclic stresses. The ends 102, 104 can be engaged and fixed in the channel.

[0155] Figure 11Illustrated is another device or implant or prosthesis 140 that provides fluid flow through at least one channel. As described with respect to device 100, device 140 includes a proximal portion 102, a distal portion 104, and an intermediate portion 106. Device 140 includes a polymeric tube 108 and a support structure that includes a first mesh 142 and a second mesh 144. The first mesh 142 extends from the proximal portion 102 toward (e.g., into) the intermediate portion 106 and optionally into the distal portion 104. The second mesh 144 extends from the distal portion 104 toward (e.g., into) the intermediate portion 106 and optionally into the proximal portion 102. The meshes 142, 144 thus overlap each other at least at the intermediate portion 106. Both meshes 142, 144 can 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 differently on the outside of the tube 108, on the inside of the tube 108, or embedded within the tube 108 (e.g., one mesh is inside the tube 108 and one mesh is outside the tube 108). The meshes 142, 144 can be formed, for example, by winding wire in a grid configuration around or inside the polymeric tube 108, by placing cut tube around or inside the polymeric tube 108, by being embedded within the polymeric tube 108, combinations thereof, and the like.

[0156] In some embodiments, the density of the meshes 142, 144 is relatively high in their respective ends 102, 104 (or the window size of the meshes 142, 144 is relatively small) and decreases in density (or increases in window size) toward the intermediate portion 106. The total winding density (e.g., the combined winding density of both meshes 142, 144) can be lower in the intermediate portion 106 than in the ends 102, 104, or the total window size (e.g., the combined window size of both meshes 142, 144) can be larger in the intermediate portion 106 than in the ends 102, 104. In certain such embodiments, the intermediate portion 106 is relatively flexible compared to the ends 102, 104. In some embodiments, the meshes 142, 144 do not extend into the intermediate portion and there is no mesh such that the intermediate portion 106 is relatively flexible compared to the ends 102, 104. In some embodiments, as the window size increases (e.g., longitudinally along a tapered portion of 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 in proportion to the window size, which can provide a change in flexibility along the longitudinal length.

[0157] The first and second meshes 142, 144 may comprise different materials, which for a particular application of the device 140 may optimize the performance of each of the respective distal and proximal portions 102, 104 of the device 140. For example, the second mesh 144 at the distal portion 104 of the device 140 may comprise a relatively flexible metal alloy to facilitate insertion through the interconnecting channel between two blood vessels, while the first mesh 142 at the proximal portion 102 of the device 140 may comprise a relatively inelastic metal alloy to provide a high degree of elasticity at the proximal portion 104 to securely fix the device 140 in place. The first and second meshes 142, 144 may comprise the same material composition (e.g., both comprise nitinol) but different wire diameters (gauges) or strut thicknesses.

[0158] Figure 12 Another device or implant or prosthesis 150 is illustrated that provides fluid flow through at least one channel. 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 portion 102, a distal portion 104, and an intermediate portion 106. The proximal portion 102 includes a cylindrical or substantially cylindrical portion and the distal portion 104 includes a cylindrical or substantially cylindrical portion. The diameter of the proximal portion 102 is less than the diameter of the distal portion 104. In some embodiments, the diameter of the proximal portion 102 is greater than the diameter of the distal portion 104. The intermediate portion 106 has a tapered or frustoconical shape between the proximal portion 102 and the distal portion 104. The stent 152 may comprise filaments (e.g., woven, layered), cut tubes or plates, and / or combinations thereof.

[0159] The parameters of the stent 152 may be uniform or substantially uniform across one portion and / or across multiple portions, or may vary within one portion and / or across multiple portions. For example, the stent 152 at the proximal portion 102 may comprise a cut tube or plate, the stent 152 at the distal portion 102 may comprise a cut tube or plate, and the stent 152 at the intermediate portion 106 may comprise filaments (e.g., woven or layered). Certain such embodiments may provide good fixation through the good flexibility (e.g., adaptability to the third channel size and dynamic stress) of the proximal portion 102, the distal portion 104, and the intermediate portion 106.

[0160] The stent 152 may include different materials in different portions. For example, the stent 152 at the proximal portion 102 may include chromium cobalt and / or tantalum, the stent 152 at the distal portion 104 may include nitinol, and the stent 152 at the intermediate portion 106 may include nitinol. Some such embodiments may provide good fixation and / or apposition (e.g., the proximal portion 102 engages the sidewall of the artery, the distal portion 104 engages the sidewall of the vein, and the intermediate portion 106 engages the sidewall of the channel between the artery and the vein) through the device 150 in each deployment region. In some embodiments where the distal portion 104 is self-expanding, the distal portion 104 may adapt, for example, by further self-expanding due to a changed vessel diameter (e.g., if the vein diameter increases due to increased blood pressure or blood flow).

[0161] Combinations of support structure materials and types are also possible. For example, the stent 152 at the proximal portion may include a cut tube or plate containing chromium cobalt and / or tantalum, the stent 152 at the distal portion 104 may include a cut tube or plate containing nitinol, and the stent 152 at the intermediate portion 106 may include filaments containing nitinol.

[0162] In embodiments where the stent 152 includes at least a portion containing a cut tube or plate, the cutting pattern may be the same. For example, the cutting pattern may be the same in the proximal portion 102 and the distal portion 104, but the diameters are proportionally changed. In some embodiments, the window 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 where the stent 152 includes at least a portion containing filaments, the winding may be the same. For example, the winding may be the same in the proximal portion 102 and the distal portion 104, but changes due to the change in diameter. In some embodiments, the winding density or porosity is uniform or substantially uniform within the portions 102, 104, 106, within two or more of the portions 102, 104, 106, and / or from one end of the stent 152 to the other end of the stent 152. In embodiments where the stent 152 includes at least a portion containing a cut tube or plate and at least a portion containing filaments, the cutting pattern and the winding may be configured to result in a uniform or substantially uniform density. Non-uniformity is also possible, such as described herein.

[0163] As described with respect to tube 108, graft 154 may include material and be attached to stent 152. Graft 154 generally forms a fluid-tight passage for at least a portion of device 150. Although the illustration is only around middle portion 106, graft 154 may extend the entire length of device 150, or may partially overlap into at least one of cylindrical ends 102, 104.

[0164] Figure 13 Another device 160 is illustrated that provides fluid flow through at least one channel. Device 160 includes a support structure (e.g., a stent) and graft 164. As described with respect to device 100, device 160 includes a proximal portion 102, a distal portion 104, and a middle portion 106. Proximal portion 102 includes a tapered or frustoconical portion, and distal portion 104 includes a tapered or frustoconical portion. The diameter of the proximal end of proximal portion 102 is less than the diameter of the distal end of distal portion 104. In some embodiments, the diameter of the proximal end of proximal portion 102 is greater than the diameter of the distal end of distal portion 104. Middle portion 106 has a tapered or frustoconical shape between proximal portion 102 and distal portion 104. In some embodiments, the angles of inclination of portions 102, 104, 106 are the same or substantially the same (e.g., as Figure 13 illustrated). In some embodiments, the angle of inclination of at least one portion is sharper or narrower than at least one other portion. The frustoconical proximal portion 102 and distal portion 104 may provide better fixation in a body passage, e.g., because arteries tend to taper with distance from the heart and veins tend to taper with distance toward the heart, and ends 102, 104 may be configured to at least partially correspond to such anatomical tapering.

[0165] Figure 12 Device 150 is illustrated that includes a first cylindrical or straight portion, a conical or tapered portion, and a second cylindrical or straight portion. Figure 13Illustrated is device 160, which includes one or more conical or tapered portions (e.g., the entire device 160 is conical or tapered or includes multiple conical or tapered portions). In some embodiments, a combination of devices 150, 160 is possible. For example, for the remainder of the device, the device can include cylindrical or straight portions and conical or tapered portions. In certain such embodiments, the length of the device can be between about 1 cm and about 10 cm (e.g., about 5 cm), which includes cylindrical or straight portions and conical or tapered portions, the diameter of the cylindrical or straight portion being between about 1 mm and about 5 mm (e.g., about 3 mm) and the length being between about 0.5 cm and about 4 cm (e.g., about 2 cm), the diameter of the conical or tapered portion increasing from the diameter of the cylindrical or straight portion to a diameter between about 3 mm and about 10 mm (e.g., about 5 mm) and the length being between about 1 cm and about 6 cm (e.g., about 3 cm). Such a device can be without another cylindrical or conical portion thereafter.

[0166] As described above with respect to support structure 152, support structure 162 can include filaments (e.g., woven, layered), cut tubes or plates, the same material, different materials, and combinations thereof.

[0167] As described with respect to tube 108, graft 164 can include material and be attached to stent 162. Graft 164 generally forms a liquid-tight passage for at least a portion of device 160. Although illustrated as only surrounding intermediate portion 106, graft 164 can extend the entire length of device 160 or can partially overlap into at least one of frustoconical ends 102, 104.

[0168] In some embodiments, a combination of device 150 and device 160 is possible. For example, proximal portion 102 can be cylindrical or substantially cylindrical (e.g., as in device 150), distal portion 104 can be tapered or frustoconical (e.g., as in device 160), and proximal portion 102 has a greater diameter than the distal end of distal portion 104. For another example, proximal portion 102 can be tapered or frustoconical (e.g., as in device 160), distal portion 104 can be cylindrical or substantially cylindrical (e.g., as in device 150), and the proximal end of proximal portion 102 has a greater diameter than distal portion 104. In each embodiment, intermediate portion 106 can have a tapered or frustoconical shape between proximal portion 102 and distal portion 104.

[0169] Examples of the portable devices described herein, the deployment devices, are described in U.S. Patent Application No. 12 / 545,982, filed on August 24, 2009, and U.S. Patent Application No. 13 / 486,249, filed on June 1, 2012, the entire content of each of which is incorporated herein by reference. The devices generally include a combination of a handle having a user-actuable trigger at the proximal end and a tubular member at the distal end configured to push and / or pull to deploy the device after actuation of the trigger. Other delivery devices are also possible. The delivery device may include a portion slidable over a guide wire (e.g., a guide wire for manipulating a tissue-piercing needle between arteries and veins) and / or may be advanceable through the lumen of a catheter.

[0170] Although certain embodiments and examples are shown or described in detail herein, different combinations, sub-combinations, improvements, variations, substitutions, and omissions of the specific features and aspects of those embodiments are possible, some of which will now be described only by way of example.

[0171] Devices, such as the stent of the device, the mesh of the device, the support structure of the device, etc., may be self-expanding. For example, the mesh may include a shape memory material, such as nitinol, which is capable of returning or configured to return to a pre-set shape after undergoing deformation. In some embodiments, the stent may be manufactured in such a shape that is desired in the expanded configuration and is compressible for mounting within a sleeve for transportation to a vascular site on a catheter. To deploy and expand the stent, the sleeve is withdrawn from the stent to allow the shape memory material to return to the pre-set shape, which may fix the stent in the passage, and if the stent has sufficient radial strength, it may expand the passage. The use of a balloon catheter is not required to expand a fully self-expanding stent, but may be used, for example, to improve or optimize deployment.

[0172] The device may include one or more self-expanding portions and one or more portions expandable by deformation, such as using a balloon catheter. For example, in Figure 11 the embodiment shown, the first mesh 142 may include stainless steel expandable by a balloon catheter, and the second mesh 144 may include nitinol that is self-expanding after deployment.

[0173] Regarding any of the embodiments described herein, the polymer tubes 108 containing the grafts 154, 164 may include any suitable compliant or flexible polymer, such as PTFE, silicone, polyethylene terephthalate (PET), polyurethane such as polycarbonate aromatic bio-durable thermoplastic polyurethane elastomer (e.g., ChronoFlex Medical grade 80A and 55D, available from AdvanSource Biomaterials, Wilmington, Massachusetts, combinations thereof, etc. The polymeric tube 108 can include biodegradable, bioabsorbable, biocompatible polymers (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycolic-lactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.). The polymer can be in the form of a tube before interacting with a support structure (e.g., a stent), or can be formed on, in, and / or around a support structure (e.g., a stent). For example, the polymer can include spun fibers, dip coatings, combinations thereof, etc. In some embodiments, e.g., when the device is deployed in a single blood vessel, the device can omit the tube. In certain such embodiments, the middle portion of the stent can include a mesh with a low winding density or large window size, while the ends of the stent include a mesh with a higher winding density or smaller window size, and the mesh is generally tubular to define a path for fluid flow through the center of the mesh. In some embodiments, the polymeric tube 108 includes an edge (e.g., including the same or different materials), which can help form a liquid-tight seal between the polymeric tube 108 and the body passage. The seal can be angled, e.g., to account for the angled placement of the polymeric tube 108 between body passages. In some embodiments, the polymeric tube 108 can longitudinally extend in at least one direction beyond the support structure, and the extended portion is not supported by the support structure.

[0174] The mesh can include any suitable material, such as nickel, titanium, chromium, cobalt, tantalum, platinum, tungsten, iron, manganese, molybdenum, combinations thereof (e.g., nitinol, cobalt chrome, stainless steel), etc. The mesh can include biodegradable, bioabsorbable, or biocompatible polymers (e.g., polylactic acid (PLA), polyglycolic acid (PGA), polyglycolic-lactic acid (PLGA), polycaprolactone (PCL), polyorthoesters, polyanhydrides, combinations thereof, etc.) and / or glass, and can be devoid of metal. For example, as previously described with respect to Figure 11As described, different materials can be used for portions of the mesh or within the same mesh. For example, the mesh 114 at the distal portion 104 of the device 100 and the mesh 112 at the proximal portion 102 can include different materials. For another embodiment, the mesh 112 and / or the mesh 114 can include a metal alloy (e.g., including cobalt, chromium, nickel, titanium, combinations thereof, etc.) in combination with different types of metal alloys (e.g., a shape memory alloy in combination with a non-shape memory alloy, a first shape memory alloy in combination with a second shape memory alloy different from the first shape memory alloy, a clad material (e.g., including a core that includes a radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc.)) and / or non-metallic materials such as polymers (such as polyester fibers), carbon, and / or bioabsorbable fiberglass. In some embodiments, at least one of the meshes 112, 114 includes nitinol and stainless steel. The nitinol can allow for some self-expansion (e.g., partial and / or full self-expansion), and the mesh can then be further expanded, for example, using a balloon.

[0175] Although generally illustrated as a woven filament mesh in Figure 8 、 10 and 11, any other structure that provides the desired degree of elasticity can be used. For example, layers of filaments wound in opposite directions can be fused at the filament ends to provide an expandable structure. For another embodiment, a metal plate can be cut (e.g., laser cut, chemically etched, plasma cut, etc.) to form perforations and then heat set into a tubular shape, or a metal tube (e.g., a hypotube) can be cut (e.g., laser cut, chemically etched, plasma cut, etc.) to form perforations. The cut tube (including a cut plate rolled into a tube) can be heat set to impart an expanded configuration.

[0176] Filaments, threads, or ribbons that can be woven or knitted, or layered or otherwise arranged are typically elongated and have a cross-section that is circular, oval, square, rectangular, etc. Example non-woven filaments can include 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 attachment to an expandable loop). Example knitting patterns include one-over-one-under-one, one-over-two-under-two, two-over-two-under-two, and / or combinations thereof, but other knitting patterns are possible. At filament crossings, the filaments can be helically wrapped, cross in a sliding relationship, and / or combinations thereof. The filaments can be loose (e.g., held together by weaving) and / or include weld points, joining elements such as sleeves, and / or combinations thereof. The ends of the filaments can be bent back, curled (e.g., with ends curled of a radiopaque material that can also act as a radiopaque marker, the radiopaque material such as titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, etc.), twisted, ball welded, attached to a loop, combinations thereof, and so on. The woven ends can include filament ends and / or filaments bent back, and can include open cells, fixed or unfixed filaments, weld points, adhesives, or other means of fusion, radiopaque markers, combinations thereof, and so on. The parameters of the filaments can be uniform or substantially uniform throughout a portion and / or throughout multiple portions, or can vary within a portion and / or throughout multiple portions. For example, the proximal portion 102 can include a first parameter and the distal portion 104 can include a second parameter different from the first knitting pattern. For another embodiment, the proximal portion 102 and the distal portion 104 can each include a first parameter and the intermediate portion 106 can include a second parameter different from that parameter. For yet another embodiment, at least one of the proximal portion 102, the distal portion 104, and the intermediate portion 106 can include both a first parameter and a second parameter different from the first parameter. Filament parameters can include, for example, filament type, filament thickness, filament material, filament number, weaving pattern, layering, winding direction, pitch, angle, crossing type, filament joining or lack thereof, filament end treatment, woven end treatment, layering end treatment, number of layers, presence or absence of weld points, radiopacity, knitting pattern, density, porosity, filament angle, knitting diameter, winding diameter, and shape setting.

[0177] Tubes or plates can be cut to form strut or pore (cell) patterns, where struts are the portions of the tube or plate remaining after cutting, and pores or perforations or windows are the portions cut away. Tubes (e.g., Hypotubes) can be cut directly, or plates can be cut and then rolled into tubes. The tube or plate can be shaped before or after cutting. The tube or plate can be welded or otherwise joined to itself, to another tube or plate, to filaments, to graft materials, etc. Cutting can be by laser, chemical etchant, plasma, combinations thereof, etc. Example cutting patterns include helical spiral, weave-like, coil, single loop, continuous loop, open cell, closed cell, combinations thereof, etc. In embodiments that include continuous loops, flex connectors, non-flex connectors, and / or combinations thereof can be used to join the loops. In embodiments that include continuous loops, loop connectors (e.g., flex, non-flex, and / or combinations thereof) can cross ring peaks, ring valleys, middle portions of struts, and / or combinations thereof (e.g., peak-peak, valley-valley, middle-middle, peak-valley, peak-middle, valley-middle, valley-peak, middle-peak, middle-valley). The tube or plate or portions thereof can be ground or polished before or after cutting. For example, internal ridges can be formed to assist fluid flow. The parameters for cutting the tube or plate can be uniform or substantially uniform throughout a portion and / or throughout multiple portions, or can vary within a portion and / or throughout multiple portions. For example, the proximal portion 102 can include a first parameter and the distal portion 104 can include a second parameter different from the first parameter. For another example, the proximal portion 102 and the distal portion 104 can each include a first parameter and the middle portion 106 can include a second parameter different from that parameter. For another example, at least one of the proximal portion 102, the distal portion 104, and the middle portion 106 can include both a first parameter and a second parameter different from the first parameter. Cutting tube or plate parameters can include, for example, radial strut thickness, circumferential strut width, strut shape, pore shape, cutting pattern, cutting type, material, density, porosity, tube diameter, and shaping.

[0178] In some embodiments, the perforations can provide a mesh having a relatively flexible middle portion and relatively rigid ends. The support structure can alternatively be an open-cell foam disposed within the tube.

[0179] The filaments of a stent, stent graft, or a portion thereof, and / or the struts of a cutting stent, stent graft, or a portion thereof can be surface modified, for example to carry drugs such as thrombogenic modifiers, fluid flow modifiers, antibiotics, etc. The filaments of a stent, stent graft, or a portion thereof, and / or the struts of a cutting stent, stent graft, or a portion thereof can be at least partially covered with a coating including a drug, such as a thrombogenic modifier, a fluid flow modifier, an antibiotic, etc., embedded within a polymer layer or a series of polymer layers, and the polymer layer can be the same as or different from the polymer tube 108.

[0180] The filaments of a stent, a stent graft, or a portion thereof, and / or the thickness (e.g., diameter) of the struts of a cutting stent, a stent graft, or a portion thereof can be between about 0.0005 inches and about 0.02 inches, between about 0.0005 inches and about 0.015 inches, between about 0.0005 inches and about 0.01 inches, between about 0.0005 inches and about 0.008 inches, between about 0.0005 inches and about 0.007 inches, between about 0.0005 inches and about 0.006 inches, between about 0.0005 inches and about 0.005 inches, between about 0.0005 inches and about 0.004 inches, between about 0.0005 inches and about 0.003 inches, between about 0.0005 inches and about 0.002 inches, between about 0.0005 inches and about 0.001 inches, between about 0.001 inches and about 0.02 inches, between about 0.001 inches and about 0.015 inches, between about 0.001 inches and about 0.01 inches, between about 0.001 inches and about 0.008 inches, between about 0.001 inches and about 0.007 inches, between about 0.001 inches and about 0.006 inches, between about 0.001 inches and about 0.005 inches, between about 0.001 inches and about 0.004 inches, between about 0.001 inches and about 0.003 inches, between about 0.001 inches and about 0.002 inches, between about 0.002 inches and about 0.02 inches, between about 0.002 inches and about 0.015 inches, between about 0.002 inches and about 0.01 inches, between about 0.002 inches and about 0.008 inches, between about 0.002 inches and about 0.007 inches, between about 0.002 inches and about 0.006 inches, between about 0.002 inches and about 0.005 inches, between about 0.002 inches and about 0.004 inches, between about 0.002 inches and about 0.003 inches, between about 0.003 inches and about 0.02 inches, between about 0.003 inches and about 0.015 inches, between about 0.003 inches and about 0.01 inches, between about 0.003 inches and about 0.008 inches, between about 0.003 inches and about 0.007 inches, between about 0.003 inches and about 0.006 inches, between about 0.003 inches and about 0.005 inches, between about 0.003 inches and about 0.004 inches, between about 0.004 inches and about 0.02 inches, between about 0.004 inches and about 0.015 inches, between about 0.004 inches and about 0.01 inches, between about 0.Between about 0.004 inches and about 0.008 inches, between about 0.004 inches and about 0.007 inches, between about 0.004 inches and about 0.006 inches, between about 0.004 inches and about 0.005 inches, between about 0.005 inches and about 0.02 inches, between about 0.005 inches and about 0.015 inches, between about 0.005 inches and about 0.01 inches, between about 0.005 inches and about 0.008 inches, between about 0.005 inches and about 0.007 inches, between about 0.005 inches and about 0.006 inches, between about 0.006 inches and about 0.02 inches, between about 0.006 inches and about 0.015 inches, between about 0.006 inches and about 0.01 inches, between about 0.006 inches and about 0.008 inches, between about 0.006 inches and about 0.007 inches, between about 0.007 inches and about 0.02 inches, between about 0.007 inches and about 0.015 inches, between about 0.007 inches and about 0.01 inches, between about 0.007 inches and about 0.008 inches, between about 0.008 inches and about 0.02 inches, between about 0.008 inches and about 0.015 inches, between about 0.008 inches and about 0.01 inches, between about 0.01 inches and about 0.02 inches, between about 0.01 inches and about 0.015 inches, or between about 0.015 inches and about 0.02 inches. Other thicknesses are possible, including thicknesses greater than or less than the identified thicknesses. Filaments and / or struts incorporating certain materials (e.g., biodegradable materials, materials with lower resilience, etc.) can be thicker than the identified thicknesses.

[0181] For example, the thickness of the filaments and / or struts can be based on at least one of the following: the size of the device or device part (e.g., diameter and / or length), porosity, radial strength, material, the number of filaments and / or struts, cutting pattern, weaving pattern, layering pattern, etc. For example, a larger filaments and / or struts thickness (e.g., greater than about 0.006 inches) can be used for large devices or device parts for treating large blood vessels such as coronary vessels, a medium filaments and / or struts thickness (e.g., between about 0.003 inches and about 0.006 inches) can be used for medium-sized devices or device parts for treating medium-sized blood vessels such as peripheral vessels, and a small filaments and / or struts thickness (e.g., less than about 0.003 inches) can be used for small devices or device parts for treating small blood vessels such as veins and neurovascular vessels.

[0182] The inner diameter or outer diameter of the stent, stent graft, or the first end, second end, intermediate portion, or sub-portions thereof, e.g., considering the filament or strut thickness, can be between about 1 mm and about 12 mm, between about 1 mm and about 10 mm, between about 1 mm and about 8 mm, between about 1 mm and about 6 mm, between about 1 mm and about 4 mm, between about 1 mm and about 2 mm, between about 2 mm and about 12 mm, between about 2 mm and about 10 mm, between about 2 mm and about 8 mm, between about 2 mm and about 6 mm, between about 2 mm and about 4 mm, between about 4 mm and about 12 mm, between about 4 mm and about 10 mm, between about 4 mm and about 8 mm, between about 4 mm and about 6 mm, between about 6 mm and about 12 mm, between about 6 mm and about 10 mm, between about 6 mm and about 8 mm, between about 8 mm and about 12 mm, between about 8 mm and about 10 mm, or between about 10 mm and about 12 mm. Some such diameters may be suitable for treating, e.g., coronary vessels. The inner diameter or outer diameter of the stent, stent graft, or a portion thereof, e.g., considering the filament or strut thickness, can be between about 1 mm and about 10 mm, between about 1 mm and about 8 mm, between about 1 mm and about 6 mm, between about 1 mm and about 4 mm, between about 1 mm and about 2 mm, between about 2 mm and about 10 mm, between about 2 mm and about 8 mm, between about 2 mm and about 6 mm, between about 2 mm and about 4 mm, between about 4 mm and about 10 mm, between about 4 mm and about 8 mm, between about 4 mm and about 6 mm, between about 6 mm and about 10 mm, between about 6 mm and about 8 mm, or between about 8 mm and about 10 mm. Some such diameters may be suitable for treating, e.g., veins. The inner diameter or outer diameter of the stent, stent graft, or a portion thereof, e.g., considering the filament or strut thickness, can be between about 6 mm and about 25 mm, between about 6 mm and about 20 mm, between about 6 mm and about 15 mm, between about 6 mm and about 12 mm, between about 6 mm and about 9 mm, between about 9 mm and about 25 mm, between about 9 mm and about 20 mm, between about 9 mm and about 15 mm, between about 9 mm and about 12 mm, between about 12 mm and about 25 mm, between about 12 mm and about 20 mm, between about 12 mm and about 15 mm, between about 15 mm and about 25 mm, between about 15 mm and about 20 mm, or between about 20 mm and about 25 mm. Some such diameters may be suitable for treating, e.g., peripheral vessels.The inner or outer diameter of a stent, stent graft, or a portion thereof, e.g., considering filament or strut thickness, can be between about 20 mm and about 50 mm, between about 20 mm and about 40 mm, between about 20 mm and about 35 mm, between about 20 mm and about 30 mm, between about 30 mm and about 50 mm, between about 30 mm and about 40 mm, between about 30 mm and about 35 mm, between about 35 mm and about 50 mm, between about 35 mm and about 40 mm, between about 40 mm and about 50 mm. Some such diameters may be suitable for treating, e.g., the aortic blood vessel. Other diameters are also possible, including diameters greater than or less than the identified diameters. The diameter of the device can refer to the diameter of the first end, second end, or middle portion, each of which can be in an expanded or unexpanded form. When all parts of the device are in an expanded or unexpanded form, the diameter of the device can refer to the average diameter of the device.

[0183] The length of a stent, stent graft, or the first end, second end, middle portion, or a sub - portion thereof can be between about 5 mm and about 150 mm, between about 5 mm and about 110 mm, between about 5 mm and about 70 mm, between about 5 mm and about 50 mm, between about 5 mm and about 25 mm, between about 5 mm and about 20 mm, between about 5 mm and about 10 mm, between about 10 mm and about 150 mm, between about 10 mm and about 110 mm, between about 10 mm and about 70 mm, between about 10 mm and about 50 mm, between about 10 mm and about 25 mm, between about 10 mm and about 20 mm, between about 20 mm and about 150 mm, between about 20 mm and about 110 mm, between about 20 mm and about 70 mm, between about 20 mm and about 50 mm, between about 20 mm and about 25 mm, between about 25 mm and about 150 mm, between about 25 mm and about 110 mm, between about 25 mm and about 70 mm, between about 25 mm and about 50 mm, between about 50 mm and about 150 mm, between about 50 mm and about 110 mm, between about 50 mm and about 70 mm, between about 70 mm and about 150 mm, between about 70 mm and about 110 mm, or between about 110 mm and about 150 mm. Other lengths are also possible, including lengths greater than or less than the identified lengths.

[0184] The porosity of the stent, stent graft, or the first end, second end, intermediate portion, or sub-portions thereof can be between about 5% and about 95%, between about 5% and about 50%, between about 5% and about 25%, between about 5% and about 10%, between about 10% and about 50%, between about 10% and about 25%, between about 25% and about 50%, between about 50% and about 95%, between about 50% and about 75%, between about 50% and about 60%, between about 60% and about 95%, between about 75% and about 90%, between about 60% and about 75%, and combinations thereof. The density of the stent can be the reciprocal of the porosity of the stent. The porosity of the portion of the stent covered by the graft can be about 0%. For certain portions of the stent, the porosity can vary depending on the purpose. For example, the intermediate portion can have a low porosity to increase fluid flow through the device, while the ends can have a lower porosity to increase flexibility and wall attachment.

[0185] The radial strength or pressure resistance of the stent, stent graft, or the first end, second end, intermediate portion, or sub-portions thereof can be between about 0.1 N / mm and about 0.5 N / mm, between about 0.2 N / mm and about 0.5 N / mm, between about 0.3 N / mm and about 0.5 N / mm, between about 0.1 N / mm and about 0.3 N / mm, between about 0.1 N / mm and about 0.2 N / mm, between about 0.2 N / mm and about 0.5 N / mm, between about 0.2 N / mm and about 0.3 N / mm, or between about 0.3 N / mm and about 0.5 N / mm.

[0186] Certain parameter values of the stent, stent graft, or the first end, second end, intermediate portion, or sub-portions thereof can be related (e.g., proportional). For example, the ratio of the thickness of the struts or filaments to the diameter of the portion of the device containing the struts or filaments can be between about 1:10 and about 1:250, between about 1:25 and about 1:175, or between about 1:50 and about 1:100. For another embodiment, the ratio of the length of the device or portion thereof to the diameter of the device or portion thereof can be between about 1:1 and about 50:1, between about 5:1 and about 25:1, or between about 10:1 and about 20:1.

[0187] Portions of the device may include radiopaque materials. For example, stents, stent grafts, or filaments and / or struts of the first end, second end, intermediate portion, or sub-portions thereof may include titanium, tantalum, rhenium, bismuth, silver, gold, platinum, iridium, tungsten, combinations thereof, etc. (e.g., at least partially made of). For another embodiment, filaments and / or struts of a stent, stent graft, or portion thereof may include a material having a density greater than about 9 grams per cubic centimeter (e.g., at least partially made of). Separate radiopaque markers may be attached to certain components of the device. For example, radiopaque markers may be added to the proximal end of the device or its components (e.g., proximal components of the intermediate portion, proximal components of the distal portion), the distal end of the device or its components (e.g., distal components of the intermediate portion, distal components of the proximal portion), and / or other components. For example, radiopaque markers between the ends of the device may be used to demarcate transitions between materials, portions, etc. The radiopacity may vary along the length of the device. For example, the proximal portion may have a first radiopacity (e.g., due to the distal portion material and / or separate markers) and the distal portion may have a second radiopacity different from the first radiopacity (e.g., due to the distal portion material and / or separate markers).

[0188] In some embodiments, the device includes a polymer tube and does not provide a support structure. The intermediate portion of such a device may be relatively more flexible than the ends by, for example, reducing the wall thickness of the polymer tube within the intermediate portion.

[0189] When a mesh or other support structure is provided in combination with the polymer tube, the support structure may be located around the outside of the tube, within the bore of the tube, or embedded within the tube wall. More than one support structure may be provided, in which case each support structure may have a different position relative to the tube.

[0190] One or both ends of the device may include fixation elements such as hooks, bosses, or barbs configured to grip or hold the inner wall of the blood vessel. In the absence of fixation elements, the radial force of the ends after dilation may be sufficient to grip or hold the inner wall of the blood vessel.

[0191] There need not be a clearly defined transition between the intermediate portion and the ends. For example, the mesh type, material, wall thickness, flexibility, etc. may change gradually from the ends towards the intermediate portion or from the intermediate portion towards the ends.

[0192] For example, as described with respect to devices 134, 140, the flexibility of the device can increase gradually when moving from the end towards the middle portion. The change in flexibility can be due to a change in mesh density (e.g., winding density, window size), tube thickness, or other factors. The flexibility of the device can be uniform or substantially uniform along the entire length of the support structure (e.g., stent), or along certain portions of the support structure (e.g., along the entire end, along the entire middle portion, along one end and middle portion but not along the other end, etc.).

[0193] Although the devices described herein may be particularly suitable for use as transvascular shunts in percutaneous procedures, the devices can be used in many other medical applications. For example, the devices can be used in angioplasty for treating occluded blood vessels having a tortuous or kinked path, or where the blood vessel may be subject to deflection or deformation at or near the location of the stent. For example, the stent can also be used during a percutaneous procedure to repair a damaged blood vessel during an aortic graft procedure or after a perforation. In some such cases, in response to movement of the blood vessel, the middle portion of the device can cause the device to conform to the shape and deformation of the blood vessel, which has a reduced risk of fatigue failure while maintaining the ends mounted or fixed in place. For another embodiment, the device can be used to form a shunt between a healthy artery and a healthy vein for access for dialysis and / or drug administration (e.g., intermittent infusion for cancer treatment, which can damage blood vessels).

[0194] Referring again to Figure 4 and 7 , the occlusion material 251 can be used to help inhibit or prevent the backflow of arterial blood. As will now be described in further detail, additional or other methods and systems can be used to inhibit or prevent the backflow of arterial blood, or, in other words, to inhibit or prevent the arterial blood that is now flowing into the vein from flowing in the vein in the normal pre-procedure direction of blood flow such that oxygenated blood bypasses downstream tissues such as the foot.

[0195] In the absence of treatment, peripheral vascular disease (PVD) can progress to critical limb ischemia (CLI), which is characterized by deep chronic pain and extensive tissue loss that limits angioplasty options and frequently leads to amputation. It is estimated that CLI has an incidence of approximately 50 - 100 / 100,000 / year and is associated with a mortality rate of up to 20% at 6 months after onset.

[0196] Interventional radiologists have actively attempted to treat CLI by attempting to open chronic total occlusions (CTOs) or by bypassing the CTO using products such as the Medtronic Pioneer catheter in the subintimal space, which tunnels a wire into the subintimal space near the CTO and then attempts to re-enter the vessel distal to the occlusion. Once the wire is in place, the user can optionally create a wider access and then place a stent to provide a bypass catheter across the occlusion. If the wire can cross the occlusion, conventional approaches for treating PAD such as percutaneous transluminal angioplasty (PTA), stenting, and drug-eluting balloons (DEBs) can also be or optionally used in the treatment of CLI.

[0197] From the amputee - coalition.org website, the following are some statistics regarding CLI issues:

[0198] ● In the United States, nearly two million people live with limb loss.

[0199] ● Among those living with limb loss, the main contributing factors are:

[0200] o Vascular diseases (54%) (including diabetes and peripheral artery disease (PAD)),

[0201] o Trauma (45%), and

[0202] o Cancer (less than 2%).

[0203] ● In the United States, approximately 185,000 amputations occur each year.

[0204] ● In 2007, hospital costs associated with amputations totaled over $6.5 billion.

[0205] ● The survival rate after amputation varies based on many factors. Those who have had an amputation due to vascular diseases (including PAD and diabetes) face a reported 30 - day mortality rate between 9% and 15% and long - term survival rates of 60% at 1 year, 42% at 3 years, and 35% - 45% at 5 years.

[0206] ● Almost half of those who have lost a limb due to vascular disorders will die within 5 years. This is higher than the 5 - year mortality rate experienced by those with colorectal cancer, breast cancer, and prostate cancer.

[0207] ● Up to 55% of diabetics who have had a lower - limb amputation will need to have a second leg amputated within 2 to 3 years.

[0208] Since the early twentieth century, CLI has been treated surgically by open femoral vein arterialization. Over the years, many small series of clinical trials using such open femoral approaches have been published, as summarized by Lu et al. in their 2006 meta-analysis article titled "Meta-analysis of the clinical effectiveness of venous arterialization for salvage of critically ischemic limbs" in the European Journal of Vascular and Endovascular Surgery, Volume 31, pages 493-499. The article had the following results and conclusions:

[0209] ● Results:

[0210] o A total of 56 studies were selected for the review. No randomized controlled trials (RCTs) were identified.

[0211] Seven patient series including 228 patients met the selection criteria. The overall 1-year foot preservation was 71% (95% CI: 64%-77%) and the 1-year secondary patency was 46% (95% CI: 39%-53%). Most patients who avoided major amputation experienced successful wound healing, disappearance of rest pain, and absence of serious complications.

[0212] ● Conclusions:

[0213] o Based on limited evidence, venous arterialization is considered a viable alternative before major amputation in patients with "inoperable" chronic severe limb ischemia.

[0214] In other diseases described herein, the methods and systems described herein can be used to create arteriovenous (AV) fistulas using minimally invasive endovascular surgical methods in the below-the-knee (BTK) vascular system. Such methods may be suitable for patients who: (i) have a clinical diagnosis of symptomatic severe limb ischemia as defined by Rutherford 5 or 6 (severe ischemic ulcers or symptomatic gangrene); (ii) have been evaluated by a vascular surgeon and an interventionist and determined that surgical or endovascular treatment is not possible; and / or (iii) are clearly indicated for major amputation.

[0215] 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, an emitting catheter containing a needle, etc.); a second ultrasound catheter (a venous catheter, a target catheter, etc.); and a prosthesis (e.g., a nitinol stent graft encapsulated in a delivery system (e.g., a 7Fr (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 details of other, additional, and / or modified possible components are described below.

[0216] Figure 14A is a schematic side cross-sectional view of an exemplary embodiment of an ultrasound emitting catheter 170, the ultrasound emitting catheter 170 including a needle 172 (e.g., a first ultrasound catheter, an arterial catheter (e.g., if the needle extends from an artery into a vein), a venous catheter (e.g., if the needle extends from a vein into an artery)). The catheter 170 is placed into an artery, and the needle 172 is in a retracted state inside the lumen of the catheter 170. The catheter 170 can be advanced over a guidewire (e.g., a 0.014-inch (approximately 0.36 mm) guidewire) and / or placed through a sheath in an artery (e.g., the femoral artery) and advanced until the point of complete occlusion of the artery (in the tibial artery). The catheter 170 includes a handle 174 that contains a pusher ring 176. Longitudinal or distal advancement of the pusher ring 176 can advance the needle 172 out of the lumen of the catheter 170, out of the artery, and into the vein, as described herein. Other propulsion mechanisms for the needle 172 are possible (e.g., rotational, motorized, etc.). Before, after, and / or during advancement of the needle 172, a guidewire (e.g., a 0.014-inch (approximately 0.36 mm) guidewire) can be placed through the needle 172 (e.g., as described for the guidewire 14 with respect to Figure 3 ), and this guidewire can be referred to as a crossing wire.

[0217] Figure 14B is within circle 14B Figure 14A an enlarged schematic side cross-sectional view of the distal portion of the ultrasound emitting catheter 170. After advancement or emission, the needle 172 extends radially outward from the lumen 173 of the catheter 170. In some embodiments, the lumen 173 ends near the ultrasound transmitting device 178. The needle 172 can extend along a path that is aligned (e.g., parallel to) the path of the directed ultrasound signal emitted by the ultrasound transmitting device 178. Figure 14B also shows a lumen 175 that can be used to accommodate a guidewire for advancing the catheter 170 to a desired location.

[0218] Figure 15A Schematic side view of an exemplary embodiment of an ultrasound target catheter 180 (e.g., a second ultrasound catheter, an arterial catheter (e.g., if a needle extends from a vein into an artery)), a venous catheter (e.g., if a needle extends from an artery into a vein). Figure 15B Within circle 15B Figure 15A Enlarged schematic side cross-sectional view of the ultrasound target catheter 180. Figure 15C Within circle 15C Figure 15A Enlarged schematic side cross-sectional view of the ultrasound target catheter 180. The catheter 180 can be advanced over a guide wire (e.g., a 0.014 inch (about 0.36 mm) guide wire) and / or placed through a sheath in a vein (e.g., the femoral vein) and advanced until it is near and / or parallel to the distal end of the catheter 170 and / or the point of occlusion in an artery (e.g., in the tibial vein). The catheter 180 includes an ultrasound receiving transducer 182 (e.g., an omnidirectional ultrasound receiving transducer), which can act as a target in the vein for aligning the needle 172 of the catheter 170. The catheter 180 can remain in place or be stationary or substantially stationary while the catheter 170 is rotated or moved longitudinally to obtain a good or optimal ultrasound signal indicating that the needle 172 is aligned with the catheter 180 and in the direction of the catheter 180.

[0219] The catheters 170, 180 can be connected to an ultrasound transceiver, which is connected to and controlled by a computer running transceiver software. As described in further detail herein, the catheter 170 includes a planar or directional ultrasound transmitter 178, which is configured to transmit an ultrasound signal with a low angular spread or a tight beam (e.g., a small beam width) in the direction of the path of the needle 172 after being advanced from the lumen 173 of the catheter 170. The catheter 180 includes an omnidirectional (360-degree) ultrasound receiver 182, which is configured to act as a target for the ultrasound signal transmitted by the directional transmitter 178 of the catheter 170. Rotate the catheter 170 until a peak ultrasound signal is displayed, which indicates that the needle 172 is aligned with the catheter 180, such that after the needle 172 is extended (e.g., by longitudinally advancing the loop 176 of the handle 174), the needle 172 can pass through the artery in which the catheter 170 resides, through interstitial tissue, and into the vein in which the catheter 180 resides.

[0220] Figure 16 Exemplary embodiment of a diagram for detecting catheter alignment, as can be displayed on a display device (e.g., the screen of a laptop, a tablet, a smartphone, a combination thereof, etc.) of an ultrasound system. Figure 16The figure therein shows that the signal from the delivery catheter in the artery has been received by the receiving catheter in the vein. The second frequency envelope from the right is the received signal. The distance from the left side of the illustrated screen to the leading edge of the second frequency envelope can represent the distance between the catheters. The operator can move the catheter in the artery both rotationally and longitudinally, for example until the second envelope is maximum, which indicates that the catheter is correctly oriented.

[0221] Figure 17 is a schematic side view of an exemplary embodiment of a prosthesis (e.g., a stent, a stent graft) delivery system 190. In some embodiments, the delivery system 190 is a 7Fr (approximately 2.3 mm) delivery system. Figure 18 is a schematic side view of an exemplary embodiment of a prosthesis (e.g., a stent, a stent graft) 200. In Figure 17 it, the prosthesis (e.g., prosthesis 200, other prostheses described herein, etc.) is in a compressed or coiled state near the distal end 192 of the delivery system 190. In some embodiments, the prosthesis 200 includes a shape memory stent covered with graft material, such as described above. Once the crossover wire extends from the artery to the vein, for example as described herein due to being advanced through the needle 172, the delivery system 190 can be advanced over the crossover wire. The prosthesis 200 can be deployed from the delivery system 190, for example by squeezing the trigger handle 194 of the delivery system 190, retracting the outer sheath proximally and / or advancing the prosthesis 200 distally. The prosthesis 200 can establish a flow path between the artery and the vein and through the interstitial tissue. Other types of delivery systems and prostheses are also possible.

[0222] Referring again to Figure 17, some non-limiting example dimensions of the delivery system 190 are provided. The travel distance 196 of the trigger handle 194 can be, for example, between about 0.4 inches (about 1 cm) and about 12 inches (about 30 cm), between about 1 inch (about 2.5 cm) and about 8 inches (about 20 cm), or between about 2 inches (about 5 cm) and about 6 inches (about 15 cm) (e.g., about 2 inches (about 5 cm)). In some embodiments, the travel distance 196 of the trigger handle 194 is at least as long as the length of the prosthesis 200 to be deployed (e.g., in a radially expanded state). In some embodiments, a transmission or other mechanism can be employed to reduce the travel distance 196 of the trigger handle 194 to be less than the length of the prosthesis 200 to be deployed (e.g., in a radially expanded state). For example, based on at least one of the following, the distance 196 can be adjusted: the length of the prosthesis 200 to be deployed, the degree of vertical deformation of the prosthesis 200 to be deployed, the deployment mechanism (e.g., whether the outer sheath is retracted proximally, whether the prosthesis 200 is pushed distally forward, or both, whether the delivery system 190 includes a transmission mechanism, etc.), combinations thereof, and the like. The length 197 of the outer sheath or catheter portion can be, for example, between about 40 inches (about 1,020 mm) and about 50 inches (about 1,270 mm), between about 46 inches (about 1,170 mm) and about 47 inches (about 1,190 mm), or between about 46.48 inches (about 1,180 mm) and about 46.7 inches (about 1,186 mm). The overall length 198 of the delivery system 190 from the proximal tip to the distal tip can be, for example, between about 40 inches (about 1,000 mm) and about 60 inches (about 1,500 mm). For example, based on at least one of the following, the lengths 197, 198 can be adjusted: the length of the prosthesis 200 to be deployed, the degree of vertical deformation of the prosthesis 200 to be deployed, the height of the patient, the location of the occlusion being treated, combinations thereof, and the like. In some embodiments, separating the trigger handle 194 from the vascular access point by, for example, between about 10 cm and about 30 cm (e.g., at least about 20 cm) can advantageously provide easier handling or management for the user. In certain such embodiments, the length 197 can be between about 120 cm and about 130 cm (e.g., for an antegrade approach) or between about 150 cm and about 180 cm (e.g., for a contralateral approach).

[0223] Referring again to Figure 18, some non-limiting example dimensions of the prosthesis 200 are provided, depending on the environment at least in the compressed state. The thickness 201 of the structural struts can be, for example, between about 0.05 mm and about 0.5 mm or between about 0.1 mm and about 0.2 mm (e.g., about 0.143 mm). The spacing 202 between the struts of the structural struts can be, for example, between about 0.005 mm and about 0.05 mm or between about 0.01 mm and about 0.03 mm (e.g., about 0.025 mm). The thickness 203 of the connecting struts can be, for example, between about 0.05 mm and about 0.5 mm or between about 0.1 mm and about 0.2 mm (e.g., about 0.133 mm). The longitudinal length 204 of the structural member can be, for example, between about 1 mm and about 5 mm or between about 2.5 mm and about 3 mm (e.g., about 2.8 mm). The longitudinal length 205 between structural components can be, for example, between about 0.25 mm and about 1 mm or between about 0.5 mm and about 0.6 mm (e.g., about 0.565 mm). The length 206 of the struts within the structural components, including all portions that are wound back and forth, can be, for example, between about 25 mm and about 100 mm or between about 65 mm and about 70 mm (e.g., about 67.62 mm). The total longitudinal length of the prosthesis 200 can be, for example, between about 25 mm and about 150 mm or between about 50 mm and about 70 mm (e.g., about 62 mm). As described herein, many laser cut struts, woven stents, and combinations thereof, including various sizes, are possible. The struts described herein may include wires or filaments or portions that are not cut from a hypotube or plate.

[0224] The proximal and / or distal ends of the prosthesis 200 may optionally include a ring 210. The ring 210 may, for example, help secure the prosthesis 200 in an artery and / or vein. The circumferential width of the ring 210 may, for example, be between about 0.25 mm and about 1 mm or between about 0.5 mm and about 0.75 mm (e.g., about 0.63 mm). The longitudinal length 212 of the ring 210 may, for example, be between about 0.25 mm and about 2 mm or between about 0.5 mm and about 1 mm (e.g., about 0.785 mm). In some embodiments, the ratio of the total length of the prosthesis 200 to the longitudinal length 212 of the ring 210 may be between about 50:1 and about 100:1 (e.g., about 79:1). The dimensions 211, 212 of the ring 210 may be adjusted, for example, based on at least one of the following: strut thickness, diameter of the prosthesis (e.g., relative to the vessel), total length of the prosthesis, material, shaping properties, combinations thereof, and the like.

[0225] Figure 19Is a schematic side view of another exemplary embodiment of the prosthesis 220. The prosthesis 200 may have the shape of the prosthesis 220, for example in a radially expanded state (e.g., after deployment from the delivery system 190). Figure 19 Illustrates an exemplary shape of the prosthesis 220 including a first portion 221 and a second portion 225. The first portion 221 has a generally cylindrical or cylindrical shape having a length 222 between about 15 mm and about 25 mm (e.g., about 21 mm) and a diameter 223 between about 2.5 mm and about 5 mm (e.g., about 3.5 mm). The second portion 225 has a generally frustoconical or frustoconical shape having a length 226 between about 30 mm and about 50 mm (e.g., about 41 mm) and a maximum diameter 227 between about 4 mm and about 10 mm, between about 4 mm and about 7 mm (e.g., about 5.5 mm), etc. The angle of taper of the second portion 225 away from the first portion 221 may be between about 0.02 degrees and about 0.03 degrees (e.g., about 0.024 degrees).

[0226] Further details regarding prostheses that may be used in accordance with the methods and systems described herein are described in U.S. Patent Application No. 13 / 791,185, filed March 8, 2013, which is hereby incorporated by reference in its entirety.

[0227] Figures 20A - 20H Schematically illustrates an exemplary embodiment of a method for achieving retrograde perfusion. The procedure will be described with respect to the peripheral vascular system such as the calf and may also be adapted for other body cavities (e.g., cardiac, other peripheral, etc.). For clarity, certain steps such as anesthesia, incision details, suturing, etc. may be omitted. In some embodiments, the procedure may be performed from vein to artery (e.g., using a venous catheter from below).

[0228] Obtain access to the femoral artery and femoral vein. For example, using the Seldinger technique, a guiding sheath (e.g., 7Fr (about 2.3 mm)) is inserted into the femoral artery and a guiding sheath (e.g., 6Fr (about 2 mm)) is inserted into the femoral vein. A guide wire (e.g., 0.014 inches (about 0.36 mm), 0.035 inches (about 0.89 mm), 0.038 inches (about 0.97 mm)) is inserted through the guiding sheath in the femoral artery and directed into the distal portion of the diseased artery 300 in the posterior tibial or anterior tibial. A second guide wire (e.g., 0.014 inches (about 0.36 mm), 0.035 inches (about 0.89 mm), 0.038 inches (about 0.97 mm)) or a snare is inserted through the guiding sheath in the femoral vein. In embodiments where a snare is used, the third guide wire, fourth guide wire, etc. described herein are exact - even if the numbering may not be consecutive.

[0229] Percutaneously insert a venous access needle into a target vein, such as the tibial vein (e.g., the proximal tibial vein (PTV)). In some embodiments, the venous access needle can be guided under ultrasound. In some embodiments, a contrast agent can be injected into the saphenous vein (retrograde) toward the foot, and then the contrast agent will flow into the PTV. This flow path can be captured using fluoroscopy so that the venous access needle can be guided not only by ultrasound but also by fluoroscopy in addition to or instead of ultrasound.

[0230] Proximal and distal (e.g., a few inches or centimeters) to where the emission catheter 310 may reside can be accessed into the target vein. In some embodiments, the target vein can be the mid-ankle. Once the venous access needle is in the vein, insert a third guidewire (or "second" guidewire, in which case a snare is used instead of the second guidewire) into the venous access needle and advance it anterogradely in the target vein until the femoral vein. This access method can advantageously reduce problems caused by retrograde advancement of a wire through a venous valve, which is described in further detail below. For example, use fluoroscopy to guide and snare the third guidewire and pull it through the femoral vein. Insert the target catheter 320 over the third guidewire that has been snared into the femoral vein sheath. The target catheter 320 is advanced over the third guidewire into the venous system until the target catheter is near and / or parallel and / or adjacent to the occlusion 304 in the distal portion of the diseased artery of the posterior tibial or anterior tibial, as Figure 20A shown.

[0231] In some embodiments, the third guidewire can include an ultrasound receiving transducer (e.g., omnidirectional) that is mounted to provide a target for the signal emitted by the emission catheter 310 or the target catheter 320 can be advanced over the third guidewire, either of which can allow for the omission of certain techniques (e.g., femoral vein access, introducing a venous guiding sheath, inserting a second guidewire, advancing the third guidewire anterogradely until the femoral vein, capturing the third guidewire, advancing the target catheter 320 over the third guidewire).

[0232] In some embodiments, direct access to the PTV can be achieved, for example, using ultrasound, which can allow the target catheter 320 to be placed directly into the PTV, for example, using a small sheath, which can allow for the omission of certain techniques (e.g., femoral vein access, introducing a venous guiding sheath, inserting a second guidewire, advancing the third guidewire anterogradely until the femoral vein).

[0233] In some embodiments, the catheter 320 is not an over-the-wire catheter but includes a guidewire and an ultrasound receiving transducer (e.g., omnidirectional). The catheter 320 can be inserted as the third guidewire - as discussed above, as the second guidewire, or as a guidewire through a small sheath when accessing the PTV directly.

[0234] An ultrasonic transducer typically includes two electrodes, the electrodes including surfaces separated by a vibratable ceramic. An incoming or received ultrasonic signal wave can be coupled into a length extension mode, as Figure 21 shown in. Figure 21 FIG. Figure 21 is a schematic perspective view of an exemplary embodiment of an ultrasonic receiving transducer 350. If the proximal or top end 352 and the distal or bottom end 354 of the transducer 350 are conductive and electrically connected to a wire, the transducer can receive ultrasonic signals. In some embodiments, the length of the transducer 350 is between approximately 0.1 mm and approximately 0.4 mm (e.g., approximately 0.25 mm). In some embodiments, the overlap length 358 of the transducer 350 is between approximately 0.1 mm and approximately 0.3 mm (approximately 0.2 mm). In some embodiments, the diameter of the transducer 350 is similar to, substantially similar to, or the same as the guide wire on which it is mounted. In some embodiments, a row or series of laminates can enhance the signal receiving ability of the transducer 350.

[0235] In some embodiments, a guide wire including an ultrasonic receiving transducer can include a piezoelectric film (e.g., including plastic), which can enhance the signal receiving ability of the transducer. Figure 22 FIG. Figure 22 is a schematic cross-sectional view of another exemplary embodiment of an ultrasonic receiving transducer 360. Figure 22 The ultrasonic receiving transducer 360 shown in FIG. Figure 22 includes an optional cavity 368. The ultrasonic receiving transducer 360 includes a series of layers 362, 364, and 366. Layer 362 can include a polymer (e.g., a polyvinylidene fluoride (PVDF)) layer. Layer 364 can include an inorganic compound (e.g., tungsten carbide) layer. Layer 366 can include a polymer (e.g., polyimide) layer. The thickness of layer 366 can be between approximately 25 micrometers (μm or microns) and approximately 250 μm (e.g., at least approximately 50 μm).

[0236] The emission catheter 310 advances over a guide wire in the femoral artery and the tibial artery near the occlusion 304 and proximal to the occlusion 304, as Figure 20B shown in. The catheter 310 can be closer to the occlusion 304, depending on the suitability at that part of the anatomy of the retrograde perfusion procedure. In some embodiments, the catheter 310 can be placed in the distal portion of the posterior tibial artery or the anterior tibial artery, e.g., adjacent to the catheter 320. In some embodiments, the catheter 310 can be placed within a few inches or centimeters of the ankle.

[0237] The emission catheter 310 emits a directional ultrasonic signal. As Figure 20CAs shown by arrows 311 and 312, rotate and move the emission catheter 310 longitudinally until the signal is received by the target catheter 320. Once the signal is received, this indicates alignment such that the extension of the stylet from the emission catheter 310 will result in successful entry into the vein. Advance the stylet 314 away from the emission catheter 310, away from the tibial artery 300, and into the tibial vein 302, as Figure 20D shown. The accuracy of placing the transverse stylet 314 to form a fistula between the artery 300 and the vein 302 can be confirmed, for example, using a reference object and fluoroscopy.

[0238] In some embodiments, ultrasonic signals 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.

[0239] Referring again to Figure 16 , the display device can graphically display the signal alignment peak to allow the user to determine the alignment position. In some embodiments, the signal alignment can change color above or below a threshold, for example, from red to green. In some embodiments, an audio signal can be emitted, for example, when the alignment signal crosses the threshold, which can allow the user to stay focused on the patient rather than continuously monitoring the screen substantially.

[0240] In some embodiments, the horizontal line on the screen can be moved up during the procedure to indicate the maximum signal value or peak at that point. This line can be referred to as "peak hold". If a greater signal value is reached, the horizontal line moves to match that higher value. If no manipulation can raise the peak above the horizontal line, then that can indicate maximum alignment. If the signal peak drops below the horizontal line by a certain amount, the catheter can be moved and is no longer properly aligned. Since the alignment level indicated by the horizontal line has been achieved previously during the procedure, the user knows that such an alignment level can be achieved by further rotational manipulation and / or longitudinal manipulation.

[0241] The fourth guide wire 316 (e.g., 0.014 inches (about 0.36 mm)) (or "third" guide wire, in which case a snare is used instead of the second guide wire) is placed through the lumen of the transverse stylet 314 of the catheter 310 and enters the tibial vein 302 in a retrograde direction (towards the foot), as Figure 20E shown. External cuff pressure can be applied above the stylet crossing point to reduce the flow in the artery 300 to inhibit or prevent the formation of a hematoma, and / or to congest the vein to facilitate valve crossing. The catheters 310 and 320 can be removed, leaving the guide wire 316 in place, extending from the guiding sheath in the femoral artery, through the arterial tree, and into the tibial vein 302.

[0242] Instead of or in addition to the directional ultrasound techniques described herein, certain techniques that pass a guide wire 316 from an artery 300 to a vein 302 may be used.

[0243] In some embodiments, a tourniquet may be applied to the leg, which may increase the vein diameter. In some embodiments, an occluding agent (e.g., an occluding balloon as discussed with respect to Figure 4 and 7 etc.) may be used to increase the vein diameter. For example, the venous flow may be reversed, causing the vein to expand. A larger vein diameter may create a larger target for the transseptal needle 314, making it easier to access the vein 300 using the transseptal needle 314.

[0244] In some embodiments, a PTA balloon may be used in the target vein, and a needle catheter (e.g., Outback, available from Cordis) may target the PTA balloon under fluoroscopy. The transseptal needle 314 may pierce the PTA balloon, and a decrease in the PTA balloon pressure may confirm proper alignment of the transseptal needle 314. The PTA balloon may increase the vein diameter, creating a larger target for the transseptal needle 314 and making it easier to access the vein 300 using the transseptal needle 314. The guide wire 316 may be advanced through the transseptal needle 314 and into the PTA balloon.

[0245] In some embodiments, the PTA balloon includes, for example, a mesh (e.g., a woven mesh) embedded in the polymer of the balloon. When piercing a balloon without such a mesh, the balloon material may rupture and cause an embolus (e.g., a floating balloon piece downstream). The mesh may help limit tearing of the balloon material, which may inhibit or prevent the balloon material from causing an embolus.

[0246] In some embodiments, two PTA balloons longitudinally spaced along the axis of the catheter may be used in the target vein, and a needle catheter may target one of the PTA balloons. After piercing one of the PTA balloons with the transseptal needle 314, a contrast agent in the cavity between the PTA balloons may be released because the pierced balloon no longer acts as a dam for the contrast agent. The release of the contrast agent may be monitored using fluoroscopy. The PTA balloons may be on the same catheter or on different catheters.

[0247] In some embodiments, two PTA balloons longitudinally spaced along the axis of the catheter may be used in the target vein, and a needle catheter may target the space or cavity between the PTA balloons. After piercing the cavity with the transseptal needle 314, the contrast agent in the cavity may be disrupted. The disruption of the contrast agent may be monitored using fluoroscopy. The PTA balloons may be on the same catheter or on different catheters.

[0248] In some embodiments in which the PTA balloon is used in combination with an ultrasound target in a target vein, the PTA balloon catheter includes a PTA balloon and an ultrasound receiving transducer (e.g., omni-directional). In some such embodiments, the delivery catheter 310 may target the PTA balloon and / or the ultrasound receiving transducer under fluoroscopy, as described herein. The crossover needle 314 may pierce the PTA balloon, and a reduction in the pressure of the PTA balloon may confirm proper alignment of the crossover needle 314. The PTA balloon may increase the vein diameter, creating a larger target for the crossover needle 314 and making it easier to access the vein 300 using the crossover needle 314. The guidewire 316 may be advanced through the crossover needle 314 and into the PTA balloon.

[0249] In some embodiments, the LeMaitre device (e.g., UnBalloon TM Non-Occlusive ModelingCatheter, available from LeMaitre Vascular of Burlington, Massachusetts) may be used in the target vein. In some embodiments, the LeMaitre device may increase the vein diameter. The larger vein diameter may create a larger target for the crossover needle 314 and make it easier to access the vein 300 using the crossover needle 314. In some embodiments, the needle 314 may be inserted into the LeMaitre device. In some such embodiments, the LeMaitre device may act as a reticular target for the crossover needle 314 (e.g., including radiopaque material visible under fluoroscopy). The reticulum of the LeMaitre device may be radially expanded by advancing the proximal portion of the reticulum distally and / or retracting the distal portion of the reticulum proximally (e.g., pushing the tip together like an umbrella) and / or by self-expanding the reticulum (e.g., in embodiments in which at least some components of the reticulum include shape memory material). In some embodiments, the LeMaitre device may grip the crossover wire to hold the crossover wire in the target vein as the LeMaitre device approaches.

[0250] In some embodiments, the launch catheter 310 may include a first magnet having a first polarity and the target catheter 320 may include a second magnet having a second polarity. When the magnets are close enough such that the magnetic force moves one or both of the catheters 310, 320, the transverse needle 314 may be advanced to create a fistula between the artery 300 and the vein 302. In some embodiments, the first magnet may be circumferentially aligned with the transverse needle 314, and / or the launch catheter 310 may be magnetically shielded to provide rotational alignment. In some embodiments, the second magnet may be longitudinally relatively thin to provide longitudinal alignment. In some embodiments, the transverse needle 314 and / or the guidewire 316 may be magnetically pulled from the artery 300 to the vein 302, or vice versa. Some systems may include both ultrasound guidance and magnetic guidance. For example, ultrasound guidance may be used for initial alignment and magnetic guidance may be used for precise alignment.

[0251] Referring again to Figures 20A - 20H , the prosthesis delivery system 330 carrying the prosthesis 340 advances on the guidewire 316 through the interstitial space between the artery 300 and the vein 300 and then into the vein 300, as Figure 20F shown. In some embodiments, a separate PTA balloon catheter (e.g., approximately 2 mm) may be advanced on the guidewire 316 to pre - dilate the fistula between the artery 300 and the vein 302 and then the prosthesis delivery system 330 may be introduced. The use of the PTA balloon catheter may depend, for example, on the radial strength of the prosthesis 340.

[0252] The prosthesis 340 is deployed from the prosthesis delivery system 330, for example, by operating the trigger handle 194 ( Figure 17 ). In some embodiments, for example, if the prosthesis 340 cannot be expanded and / or advanced, the prosthesis delivery system 330 may be removed and a PTA catheter (e.g., approximately 2 mm) may be advanced on the guidewire 316 to attempt to dilate or further dilate the fistula between the artery 300 and the vein 302. Then the deployment of the prosthesis 340 may be attempted again (e.g., by self - expansion, balloon dilation, etc.). In some embodiments, the deployment of the prosthesis 340 may remodel the blood vessel, for example, expanding the diameter of the blood vessel by at least about 10%, at least about 20%, at least about 30% or more, between about 0% and about 10%, between about 0% and about 20%, between about 0% and about 30% or more. In embodiments where the prosthesis 340 is self - expanding, the degree of remodeling may change over time, for example, the prosthesis 340 expands when the blood vessel dilates or the prosthesis 340 contracts when the blood vessel constricts.

[0253] Once the prosthesis 340 is deployed, as Figure 20GAs shown, the fistula can be enlarged using a PTA catheter. The diameter of the PTA catheter (e.g., from about 3 mm to about 6 mm) can be at least partially based on the following selections: the diameter of artery 300, the diameter of vein 302, the composition of the interstitial tissue, the characteristics of prosthesis 340, combinations thereof, and the like. In some embodiments, the prosthesis delivery system 330 can include a PTA balloon catheter (e.g., proximal or distal to prosthesis 340), which can be used for one, several, or all of the optional PTA balloon catheter techniques described herein. In embodiments where the prosthesis includes a conical portion, the PTA balloon can include a conical portion. Once prosthesis 340 is in place, the prosthesis delivery system 330 can be removed, as Figure 20H shown. An AV fistula is thus formed between artery 300 and vein 302. Confirmation of the placement of the various catheters 310, 320, 330 and prosthesis 340 can be confirmed under fluoroscopy using a contrast agent injection throughout part or all of the procedure.

[0254] In some embodiments, markers (e.g., clips, lancets, scissors, pencils, etc.) can be applied (e.g., adhered to, placed on, etc.) to the skin to approximately mark the location of the fistula formed between artery 300 and vein 302 by the transseptal needle 314, and then the prosthesis 340 can be deployed. In embodiments where the user uses a sphygmomanometer inflated over the fistula to avoid bleeding, the lack of blood flow can make visualization or even estimation of the fistula site difficult, and the marker can provide such identification. In embodiments where the sending and receiving catheters are removed after fistula formation, the transseptal point can be difficult for the user to sense or determine, and the marker can provide such identification. If the fistula is to be enlarged, the midpoint of the dilation balloon can preferably be aligned with the midpoint of the fistula (e.g., to increase or maximize the aperture through the interstitial space). In some embodiments, the marker can be visualized under fluoroscopy (e.g., including radiopaque materials) to allow the user to see or remember the location of the fistula under fluoroscopy and then deploy the prosthesis 340.

[0255] Once prosthesis 340 is in place, the obstacle to blood flow through vein 302 and into the foot is the valve in the vein. Manipulating a guide wire through the venous valve can be challenging, for example because the pressure from the artery may not be sufficient to distend the vein and render the valve incompetent. The applicant has found that one or more of a number of techniques such as PTA catheters, stents, and valvulotomes can be used to incapacitate or render incompetent the venous valves distal to the AV fistula, as described in further detail below. Incapacitating the venous valves can allow blood to flow retrograde from the femoral artery, in the vein 302 in a retrograde manner, and in the vein to the venule and to the capillaries in the distal part of the venous circulation of the foot to provide oxygenated blood to the foot of a CLI patient.

[0256] In some embodiments, a high-pressure PTA balloon catheter can be used to cause venous valve incompetence (e.g., when inflated to greater than about 10 atm (about 1,013 kPa)).

[0257] In some embodiments, one or more stents can be placed across one or more venous valves to cause incompetence of those valves. For example, such a stent should have sufficient radial force to keep the valve open.

[0258] In some in-situ bypass procedures, the saphenous vein is attached to an artery in the thigh and another artery in the calf, bypassing all blockages in the artery. In some such procedures, rather than being stripped from the patient, longitudinally flipped, and used as a prosthesis, the vein remains in place so that blood flow is retrograde (with respect to the valves of the vein). A standard valvulotome can be placed into the saphenous vein from below and advanced in a collapsed state to the top, opened, and then pulled back in an open state, cutting the venous valves along the path. The cutting face of such a valvulotome faces backward so that it cuts during retraction during these procedures. Figure 23A FIG. is a schematic perspective view of an exemplary embodiment of a valvulotome 400 that can be used with such a procedure, including a proximally facing blade 402.

[0259] In some embodiments of the methods described herein, an inlet distal to the venous valve is not available, such that pulling the valvulotome backward is not possible, but pushing the reverse valvulotome forward as described herein is possible. Figure 23B FIG. is a schematic perspective view of an exemplary embodiment of a valvulotome 410 that can be used with such a procedure. The reverse valvulotome 410 includes one or more forward or distally facing blades 412 (e.g., 2 - 5 blades (e.g., 3 blades)) such that the valve can be cut when the reverse valvulotome 410 is advanced distally. There is no a priori motivation to reverse the direction of the blades of the valvulotome to form the reverse valvulotome 410 as described herein, at least because retrograde access to the vein to be disabled was not previously considered a problem. The reverse valvulotome 410 can be advanced on a guidewire 414 that can be maneuvered into the vein for causing venous valve incompetence. After forming a fistula between an artery and a vein as described herein, fluid flow in the vein is in a direction opposite to the natural or normal or pre-operative direction of fluid flow in the vein, such that the reverse valvulotome 410 is pushed in a direction opposite to the natural fluid flow but in the direction of post-fistula fluid flow.

[0260] Other systems and methods can also be used to correct valvular insufficiency in veins (e.g., cutting balloons, percutaneous transluminal angioplasty, laser ablation, ultrasonic ablation, heating, radiofrequency (RF) ablation, catheters with traumatic or non-traumatic tips being advanced and / or retracted (e.g., guiding sheaths), combinations thereof, etc.).

[0261] Retrograde crossing of venous valves prior to correcting such valvular insufficiency can also be challenging. Figure 24 FIG. 5 is a schematic perspective view of an exemplary embodiment of a LeMaitre device 420 that can be used to radially dilate veins and thus their valves. The LeMaitre device 420 includes an expandable elliptical or elongated leaflet 422, such as a self-expanding nitinol mesh. In some embodiments, a PTA balloon catheter can be used to radially dilate veins and thus their valves. In some embodiments, applying a tourniquet to the leg can radially dilate veins and thus their valves. After radial dilation, a guidewire can be advanced through the stretched valve(s) (e.g., through a dilation device such as the LeMaitre device) and a catheter (e.g., PTA, stent delivery, percutaneous transluminal angioplasty, etc.) or other over-the-wire device can be advanced over the guidewire.

[0262] While some exemplary embodiments have been disclosed in detail herein, this has been by way of example and for purposes of illustration only. The above embodiments are not intended to be limiting with respect to the scope of the appended claims. The inventors contemplate that various substitutions, changes, and modifications can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims.

[0263] While the devices described herein can be used in applications where the fluid flowing through the device is a liquid such as blood, the devices can also or alternatively be used in applications such as tracheal or bronchial surgeries where the fluid is a gas such as air. In some embodiments, the fluid can contain solid matter, such as emboli or, in gastric surgeries, the fluid includes food particles.

[0264] Although the present invention is susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are described in detail herein. However, it should be understood that the present invention is not limited to the specific forms or methods disclosed, but rather, on the contrary, the present invention covers all modifications, equivalents, and alternatives falling within the spirit and scope of the various embodiments described and the appended claims. Any method disclosed herein need not be performed in the recited order. The methods disclosed herein include certain actions taken by a practitioner; however, they may also include any third-party direction of these actions, whether explicitly or implicitly. For example, an action such as "rendering incompetent a valve in a first blood vessel" includes "directing to render incompetent a valve in a first blood vessel". The scope disclosed herein also encompasses any and all overlaps, sub-ranges, and combinations thereof. Language such as "until", "at least", "greater than", "less than", "between", etc. includes the recited numbers. Terms such as "about" or "approximately" in front of a number include the recited number. For example, "about 10 mm" includes "10 mm". A term or phrase preceded by a term such as "substantially" includes the recited term or phrase. For example, "substantially parallel" includes "parallel".

[0265] The claims set forth several embodiments of the invention. These non-limiting claims identify certain arrangements of combinations of features disclosed herein, although other arrangements of combinations of features are also included within the scope of the invention.

Claims

1. A catheter system for targeting a second passageway from a first passageway, the system comprising: a first catheter configured to be inserted into the first passageway, the first catheter including a needle; and a second catheter configured to be inserted into the second passageway, the second catheter including an expandable device, the expandable device including a mesh; wherein the needle is configured to be advanced from the first catheter in the first passageway and into the second passageway to pierce the expandable device, and wherein at least one of the following can be monitored: a decrease in pressure of the expandable device and release of a contrast agent from the expandable device, which is attributable to the needle piercing the expandable device and confirms advancement of the needle into the second passageway.

2. The catheter system of claim 1, wherein the expandable device is configured to increase the diameter of the second passageway.

3. The catheter system of claim 1, wherein at least one of the following can be monitored under fluoroscopy: a decrease in pressure of the expandable device and release of a contrast agent from the expandable device.

4. The catheter system of claim 1, wherein the first catheter includes an ultrasonic transmitting transducer and the second catheter includes an ultrasonic receiving transducer.

5. The catheter system of claim 4, wherein the ultrasonic transmitting transducer is configured to be aligned with the ultrasonic receiving transducer.

6. The catheter system of claim 5, wherein the needle is configured to be advanced after alignment between the ultrasonic transmitting transducer and the ultrasonic receiving transducer.

7. The catheter system of claim 1, wherein the expandable device includes a balloon, and wherein the mesh is configured to limit tearing of the balloon after being pierced by the needle.

8. The catheter system of claim 1, wherein the expandable device is configured to expand by inflation.

9. The catheter system of claim 1, wherein the expandable device is configured to self-expand.

10. The catheter system of claim 1, wherein the expandable device is configured to expand after at least one of advancing the proximal portion of the expandable device distally and retracting the distal portion of the expandable device proximally.

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