Systems for creating percutaneous fistulas

Abstract

A method for percutaneous fistula creation includes percutaneously inserting a medical device into a target location having a first blood vessel and a second blood vessel. Then, a fastener is deployed via the medical device to the target location. The fastener is in a first configuration before the deployment and in a second configuration after the deployment. The fastener restricts relative movement between the first blood vessel and the second blood vessel when in the second configuration. An anastomosis is percutaneously created between the first blood vessel and the second blood vessel.

Description

Background Art

[0001] Vascular access is the lifeline that supports patients with end-stage renal disease. Traditionally, patients have three different options for vascular access - central catheters, grafts, or autologous fistulas established by surgery. Clinical studies have shown that autologous fistulas can provide the best long-term clinical results, so it is the preferred method for vascular access. Vascular surgeons carefully dissect appropriate veins and then anastomose them to nearby arteries to establish fistulas. Surgically established fistulas significantly increase blood flow in the veins, resulting in increased diameter and thickness, making them available for dialysis access. The Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend that the anastomosis be established distally because the vasculature will support the maximization of the number of veins available for dialysis access.

[0002] The anastomosis established percutaneously is a new medical progress in recent years. For example, a percutaneous method is disclosed in U.S. Patent No. 9,439,710 entitled "Intravascular Arterial and Venous Anastomosis and Tissue Welding Catheter", which is expressly incorporated herein by reference in its entirety. This type of percutaneous method eliminates the need for surgical dissection of veins and suturing them to arteries. Although clinical trials have shown positive results of percutaneous fistulas, known methods are generally limited to establishing upper arm fistulas due to anatomical limitations. The main anatomical limitations are that the blood vessels must be extremely close to each other (<2mm) and in the same vascular bundle. If there is too much interstitial tissue, resulting in dispersion forces or independent movement between the blood vessels, the currently available system may not be able to fuse the blood vessels together, which may result in aneurysmal sacs or uncontrolled bleeding between the arteries and veins.

[0003] Therefore, there is a need for improved methods and devices for securing target vessels together or limiting relative motion between target vessels. Summary of the invention

[0004] The present invention provides innovative systems, devices and methods that enable two blood vessels in separate tissue planes or vascular bundles to be secured together so that an anastomosis can be percutaneously established therebetween.

[0005] In some embodiments, a method of percutaneously establishing a fistula includes percutaneously inserting a medical device into a target location having a first blood vessel and a second blood vessel. Then, a fastener is deployed to the target location via the medical device. The fastener is in a first configuration before deployment and in a second configuration after deployment. The fastener restricts relative movement between the first blood vessel and the second blood vessel when in the second configuration. An anastomosis is percutaneously created between the first blood vessel and the second blood vessel.

[0006] The present invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention, together with additional features and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying illustrative drawings.

[0008] Figure 1 A simplified isometric illustration of two blood vessels located adjacent to each other separated by a layer of interstitial fascia.

[0009] Figure 2 Flowchart of a method for percutaneously creating a fistula according to an embodiment.

[0010] Figure 3 For similar Figure 1 A view of an introducer that has been inserted subcutaneously into one of the blood vessels.

[0011] Figure 4 For similar Figure 1 and 3 A view showing the bending needle passing through the Figure 3 Advancement of the lumen in the previously positioned introducer is shown.

[0012] Figure 4a For Figure 4 End view of the arrangement shown in .

[0013] Figure 5 For similar Figure 1 , 3 -4, illustrating one side of the flexible member being applied and secured to the skin to allow access to a blood vessel.

[0014] Figure 6 For similar Figures 3 to 5 A view in which each side of the flexible member has been secured to the skin of a blood vessel and the needle has been withdrawn.

[0015] Figure 6a For Figure 6 End view of the arrangement shown in .

[0016] Figure 7 To illustrate the use of the catheter system in Figure 6 and 6a An isometric view of an anastomosis created between two fixed blood vessels is shown.

[0017] Figure 8 An isometric view showing the fixed blood vessels connected by the created anastomosis after the catheter system has been removed.

[0018] Fig. 9 For similar Figure 3-6a , which shows an alternative method for fastening blood vessels together.

[0019] Figure 9b For Fig. 9 End view of the arrangement shown in .

[0020] Fig.10 For similar Figure 3-6a , which shows another alternative method for fastening blood vessels together.

[0021] Fig.10b For Fig.10 End view of the arrangement shown in .

[0022] Fig.11 An isometric view illustrating yet another system and method for securing a superficial blood vessel.

[0023] Fig.12 2 is a diagram illustrating yet another system and method for fixing a blood vessel.

[0024] Fig.13 Schematic plan view of an alternative system for securing two blood vessels together after an anastomosis has been created.

[0025] Fig.13a For Fig.13 An enlarged plan view of a portion of the distal tip of the device shown in FIG.

[0026] Fig.13b For fastening blood vessels together after establishing anastomosis Fig.13 and 13a A plan view of the clip of the device distribution is shown.

[0027] Fig.14 Flowchart of a method for percutaneously creating a fistula according to an embodiment.

[0028] Fig.15 Illustration of two adjacent vessels where a guidewire has been placed through the first vessel, across the fascial layer, and into the second vessel.

[0029] Fig.16 For similar Fig.15 A view of the dilator and sheath placed over the guidewire.

[0030] Fig.17 For similar Figure 15-16 , which shows the positioning of the sheath and guidewire to provide access to a second blood vessel.

[0031] Fig.18 To show the traced Fig.13 , 13a Schematic diagram of the device of 13a and 13b.

[0032] Fig.19 For similar Fig.18, in which the device has been positioned to establish an anastomosis at a desired site using its anastomotic catheter, with the sheath having been retracted into the first blood vessel.

[0033] Fig. 20 For similar Figure 18-19 , where the anastomotic catheter has established the anastomosis at the desired location.

[0034] Fig.21 For similar Figure 18-20 , wherein after establishment, the deployment device has been advanced forward through the anastomosis.

[0035] Fig. 22 For similar Figure 18-21 , in which the mechanical fixation implant has been flexed open such that the vessel wall and fascia are captured within the mechanical fixation device.

[0036] Fig.23 For similar Figure 18-22 , in which the delivery device has been retracted to position the mechanical fixation device.

[0037] Fig.24 For similar Figure 18-23 , in which the mechanical fixation device is fully engaged on one end of the anastomosis.

[0038] Fig.25 For similar Figure 18-24 , which shows a completed anastomosis, in which the mechanical fixation device holds the vessel wall and fascia so that the two vessels cannot be significantly separated after the remainder of the device has been withdrawn and the exit of the fascia remains open.

[0039] Fig.26 Schematic diagram illustrating an anastomosis with a mechanical fixation device in place.

[0040] Fig. 27 and 27a For the first configuration ( Fig. 27 ) and the second configuration ( Fig.27a ) is a schematic diagram of an actuator according to an embodiment. DETAILED DESCRIPTION

[0041] The present invention relates to various devices, systems and methods for securing a superficial blood vessel to an artery prior to establishing an anastomosis (or as part of an anastomosis). The primary mechanism of the systems and methods of the present invention is based on mechanical fixation of the blood vessel using fasteners, including sutures, slings, deformable members (including those composed of or other shape memory material structure) or other structural means. The fastener can be applied percutaneously outside one or both of the blood vessels or inside one or both of the blood vessels.

[0042] In some embodiments, a method of percutaneously establishing a fistula includes percutaneously inserting a medical device into a target location having a first blood vessel and a second blood vessel. Then, a fastener is deployed to the target location via the medical device. The fastener is in a first configuration before deployment and in a second configuration after deployment. The fastener restricts relative movement between the first blood vessel and the second blood vessel when in the second configuration. An anastomosis is percutaneously created between the first blood vessel and the second blood vessel.

[0043] In some embodiments, deploying a fastener can cause relative movement between the first and second blood vessels to place the sidewall of the first blood vessel into engagement with the sidewall of the second blood vessel. Similarly, in some embodiments, deploying a fastener can bring the first and second blood vessels together (in direct contact or sufficiently close proximity) and then restrict relative movement of the blood vessels to facilitate the creation of the anastomosis.

[0044] In some embodiments, the fastener may be a flexible member (e.g., a suture, a sling, or other filament-like structure) that is deployed via a medical device into a desired position relative to the first and second blood vessels. For example, in some embodiments, the flexible member may be deployed to surround at least a portion of each of the first and second blood vessels with a portion. In some embodiments, the method may optionally include applying a pulling force to the flexible member to move the sidewall of the first blood vessel into engagement with the sidewall of the second blood vessel. In some embodiments, the method may optionally include fixing a first end of the flexible member to a first portion of the skin outside the target location, and fixing a second end of the flexible member to a second portion of the skin outside the target location. Fixing may include forming a knot in the end, applying a fixing element to the end, or applying an adhesive to at least one of the ends.

[0045] In some embodiments, the medical device can be separated from the device (e.g., catheter assembly) for establishing a fistula. For example, in some embodiments, the medical device may include an introducer, a needle, or both an introducer and a needle. In some embodiments, the method optionally includes advancing the needle in a target position to facilitate the deployment of a flexible member. In some embodiments, advancing the needle includes changing the curvature of the needle. In some embodiments, inserting the medical device includes inserting the tip of the introducer. The needle is in the cavity of the introducer to maintain the needle in a first shape before deploying the flexible member. Advancing the needle includes moving the needle out of the cavity of the introducer. The needle is converted to a second shape when it moves out of the cavity. In some embodiments, the needle is constructed of a shape memory material. In some embodiments, the needle includes an alignment feature that is meshingly received in the cavity of the introducer. The alignment feature maintains the needle in the desired orientation (i.e., ensuring that the needle will bend in the desired direction when it advances). Similarly, in some embodiments, when the needle moves out of the cavity, the needle deforms around a predetermined bending axis. The alignment feature of the needle is aligned with the predetermined bending axis.

[0046] In some embodiments, the fastener may be a deformable member that is introduced via a medical device and deforms during deployment to restrict the movement of the blood vessels, move the blood vessels into a desired proximity to each other, and fasten the blood vessels together. In some embodiments, the deformable member is maintained in the lumen of the introducer to maintain it in a first shape before the deformable member is deployed. Deployment may include advancing the deformable member out of the lumen and surrounding a portion of each of the first blood vessel and the second blood vessel in the target location. The deformable member is converted to a second shape when it moves out of the lumen.

[0047] In some embodiments, the fastener may be a deformable member that fastens the first blood vessel to the second blood vessel from within the blood vessel. For example, in some embodiments, the fastener may be an implant clip deployed within the anastomosis. Therefore, in some embodiments, the anastomosis is performed before the implant clip is deployed, and includes positioning at least one of the distal ends of the medical device or the distal ends of the catheter assembly to engage the inner surface of the side wall of the first blood vessel. The piercing member is then extended through the side wall of the first blood vessel and the side wall of the second blood vessel to create a communication aperture between the first blood vessel and the second blood vessel. The deployment then includes releasing the implant clip within the communication aperture and moving a portion of the implant clip to fasten the side wall of the first blood vessel to the side wall of the second blood vessel.

[0048] In some embodiments, the medical device used to deploy fasteners can be the same device used to establish an anastomosis. For example, in some embodiments, a catheter assembly can establish an anastomosis (i.e., can create a communicating aperture between two blood vessels) and also deploy fasteners to fasten the sidewall of a first blood vessel to the sidewall of a second blood vessel.

[0049] In some embodiments, a system for establishing a percutaneous fistula includes a fastener, an introducer, and a catheter assembly. The fastener is configured to switch between a first configuration and a second configuration. The introducer is configured to facilitate the percutaneous deployment of the fastener to a target location having a first blood vessel and a second blood vessel. The introducer defines a cavity in which at least a portion of the fastener is movably disposed. When a portion of the fastener is in the cavity, the introducer maintains the fastener in the first configuration. When the fastener is deployed from the cavity to the target location, the fastener is configured to switch to the second configuration. The fastener is configured to limit relative movement between the first blood vessel and the second blood vessel when in the second configuration.

[0050] In some embodiments, the fastener comprises a deformable member having a first substantially linear shape when in its first configuration and a second curved shape when in its second configuration. The deformable member is configured to surround at least a portion of each of the first and second blood vessels when in its second configuration. In some embodiments, the deformable member may be a needle or a fixation device. In some embodiments, when the deformable member is converted from its first configuration to its second configuration, the deformable member is configured to deform about a predetermined bending axis. The deformable member comprises an alignment feature that is meshingly received within the lumen of the introducer and aligned with the predetermined bending axis.

[0051] In some embodiments, the deformable member is a needle and the fastener includes a flexible member attached to the needle. The flexible member is configured to be advanced via the needle into the target location. The flexible member is configured to surround at least a portion of each of the first and second blood vessels to secure the first blood vessel to the second blood vessel. The flexible member can be, for example, a suture or a sling.

[0052] In certain embodiments, the system for establishing percutaneous fistula comprises a catheter assembly, an implant fixture and an actuator. The catheter assembly has a distal tip and a proximal base, wherein the distal tip can be axially movable relative to the proximal base. The proximal base and the distal tip are configured to clamp the sidewall of the first blood vessel and the sidewall of the second blood vessel, and produce anastomosis between the first blood vessel and the second blood vessel. The implant clip is configured to be removably placed in the catheter assembly. The implant clip is configured to be deployed in the anastomosis, so that the sidewall of the first blood vessel is fastened to the sidewall of the second blood vessel. The actuator is in the catheter assembly, and is configured to deploy at least a portion of the implant clip to the anastomosis. The actuator is configured to release the implant clip from the catheter assembly.

[0053] In some embodiments, the implant clip has a first portion and a second portion, and a clamping volume is defined between the first portion and the second portion. The implant clip is configured to be disposed within the anastomosis to receive the sidewall of the first blood vessel and the sidewall of the second blood vessel within the clamping volume. In some embodiments, the implant clip is configured to deform from a first configuration to a second configuration to apply a clamping force to the sidewall of the first blood vessel and the sidewall of the second blood vessel.

[0054] In certain embodiments, actuator is configured to move the first part of implant clip away from the second part of implant clip, to deploy the first part of implant clip to anastomosis. In certain embodiments, actuator is configured to maintain the second part of implant clip in catheter assembly when the first part of implant clip is deployed. Actuator is also configured to release the second part of implant clip from catheter assembly after the first part of implant clip is deployed.

[0055] In some embodiments, the actuator comprises an expandable element configured to move the first portion of the implant clip away from the second portion of the implant clip. In some embodiments, the expandable element is an inflatable member.

[0056] In certain embodiments, the method for percutaneously establishing a fistula includes advancing a catheter assembly having an actuator, a distal tip, a proximal base and containing an implant clip in a distal direction percutaneously in a target position until the distal tip of the catheter assembly passes through a first blood vessel and enters a second blood vessel, and the proximal base of the catheter assembly is in the first blood vessel. The distal tip then moves in a proximal direction relative to the proximal base to clamp the side wall of the first blood vessel and the side wall of the second blood vessel. Energy is transmitted to at least one of the proximal base or the distal tip to generate a communicating aperture between the first blood vessel and the second blood vessel. The actuator of the catheter assembly is manipulated to deform the implant clip so that the first part of the implant clip is moved outside the catheter assembly while the second part of the implant clip is maintained in the catheter assembly. The catheter assembly is then moved in a proximal direction so that the first part of the implant clip is positioned to contact the side wall of the second blood vessel. The actuator is manipulated to release the second part of the implant clip from the catheter assembly so that the second part of the implant clip is placed in contact with the side wall of the first blood vessel. The catheter assembly is then removed from the target location, leaving the implant clip within the target location.

[0057] In some embodiments, a system for establishing a percutaneous fistula includes a length of material that can take a curved and straight configuration; an introducer configured to facilitate the percutaneous entry of a length of material into a surgical site close to a pair of adjacent blood vessels, and a catheter device having relative tissue clamping and cutting surfaces configured to clamp the vessel wall tissue therebetween and cut and anastomose by the clamped vessel wall tissue. The length of material may include a curved needle that can be maintained in a straight configuration for percutaneous delivery to the surgical site. The introducer may include an instrument with a clamping surface for holding and manipulating the proximal end of the curved needle. The introducer may include a main needle with a cavity disposed therethrough. The curved needle and the main needle cavity are keyed to ensure the proper orientation of the curved needle when advancing through the cavity. For example, the length of material also includes a length of suture attached to the curved needle, or a ring formed by one of a superelastic shape memory material and / or an absorbable elastic material.

[0058] The catheter device may include a relatively movable sliding distal tip and a proximal portion, one of the opposing tissue gripping and cutting surfaces disposed on the sliding distal tip and the other of the opposing tissue gripping and cutting surfaces disposed on the proximal portion.

[0059] In some embodiments, a system for establishing a percutaneous fistula may include a catheter device having relative tissue gripping and cutting surfaces configured to grip vessel wall tissue therebetween and cut and anastomose by gripping the vessel wall tissue; an implant comprising a deployable gripping member disposed on the catheter device; and a deployment member movable to separate the implant from the catheter device and to deploy the implant at a surgical site. The catheter device may include a relatively movable sliding distal tip and a proximal portion, wherein one of the relative tissue gripping and cutting surfaces is disposed on the sliding distal tip, and the other of the relative tissue gripping and cutting surfaces is disposed on the proximal portion. The implant is disposed on the catheter device proximal to the sliding distal tip, and may include relative arms that can move relative to each other between a closed orientation and an open orientation. The deployment member includes a swivel that can move distally to a position disposed between the relative arms of the implant to move the relative arms toward its open orientation, and thereby separate the implant from the catheter device.

[0060] In some embodiments, a method for establishing a percutaneous fistula includes the steps of selecting an appropriate surgical site having each of a first blood vessel and a second blood vessel in close proximity to each other, fastening the first and second blood vessels together using a mechanical fastener, and establishing an anastomosis between the first and second blood vessels. The mechanical fastener includes a curved needle, and the fastening step includes inserting the curved needle percutaneously into the surgical site, and positioning the curved needle to extend around each of the two blood vessels and thereby fasten them together. The curved needle is inserted through the lumen of the main needle. The curved needle is also attached to a length of suture, and the curved needle is used to advance the length of suture so that the length of suture is wrapped around the first and second blood vessels, and the method also includes securing the end of the length of suture to a portion of the skin, and tightening the suture to approximate and hold the blood vessels in place.

[0061] Another step in the method described above is the step of securing the second end of the length of suture to the second portion of the skin. The mechanical fastener comprises a loop of material that can be deformed into a linear configuration. The step of establishing the anastomosis occurs before or after the step of fastening the first and second blood vessels together using the mechanical fastener. The mechanical fastener may comprise an implant disposed on a catheter device adapted to perform the step of establishing the anastomosis. The step of fastening the first and second blood vessels together comprises deploying the implant from the catheter device. An additional step comprises, after deployment from the catheter, moving an arm on the implant from an open position to a closed position to clamp the blood vessel wall at the surgical site adjacent to the newly formed anastomosis.

[0062] The term "about" when used in conjunction with a reference number designation means the reference number designation plus or minus up to 10% of the reference number designation. For example, "about 100" means 90 to 110.

[0063] As used herein, the term "group" may refer to a plurality of features or a single feature and a plurality of parts. For example, when reference is made to a group of walls, the group of walls may be considered to be one wall having parts, or the group of walls may be considered to be a plurality of different walls. Thus, an integrally constructed article may include a group of walls or structural components. Such a group of walls or structural components may include, for example, a plurality of parts that are continuous or discontinuous with each other. A group of walls or structural components may also be made from a plurality of articles that are produced separately and later joined together (e.g., via welding, adhesives, or any suitable method).

[0064] As used herein, the term "flexible" or "flexibility" refers to the resistance of an object to deflection, deformation, and / or displacement by an applied force, and is generally understood to be the opposite of the "stiffness" of an object. For example, a fastening member (e.g., a suture, a sling, a deformable loop, or a clip) having greater stiffness is more resistant to deflection, deformation, and / or displacement when exposed to a force than a fastening member having a lower stiffness. Similarly, a fastening member having a higher stiffness may be characterized as being more rigid than a fastening member having a lower stiffness. Flexibility may be characterized according to the amount of force applied to an object and the resulting distance that a first portion of the object is deflected, deformed, and / or displaced relative to a second portion of the object by the force.

[0065] Stiffness (and therefore flexibility) is a broad property of an object to describe, and thus depends on the material from which the object is formed, as well as certain physical properties of the object (e.g., cross-sectional shape, thickness, boundary conditions, etc.). For example, the stiffness of an object can be increased or decreased by selectively including in the object a material having a desired elastic modulus, flexural modulus, and / or hardness. In addition, the stiffness (and therefore flexibility) of an object constructed from a polymer can be affected, for example, by the chemical composition and / or arrangement of the monomers within the polymer. For example, the stiffness of an object can be reduced by reducing the chain length and / or number of branches within the polymer. The stiffness of an object can also be reduced by including a plasticizer in the polymer, which creates gaps between the polymer chains.

[0066] As used in this specification, the specific words selected to describe one or more embodiments and optional elements or features are not intended to limit the present invention. For example, spatially relative terms--for example, "under ... ", "under ... ", "lower part", "above", "upper part", "near side", "distal side", etc.--can be used to describe the relationship between an element or feature and another element or feature as illustrated in the figure. These spatially relative terms are intended to cover the different positions (that is, translation placement) and orientations (that is, rotation placement) of the device in use or operation in addition to the position and orientation shown in the figure. For example, if the device in the figure is turned upside down, then the element described as "under" other elements or features or "under" other elements or features will become "above" other elements or features or "on" other elements or features "above". Therefore, the term "under ... " can cover both the position and orientation of the upper and lower parts. The device can be oriented in other ways (for example, rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein can be interpreted accordingly. Likewise, descriptions of movement along (translation) and about (rotation) various axes include various spatial device positions and orientations.

[0067] Similarly, unless the context indicates otherwise, geometric terms such as "parallel," "perpendicular," "circular," or "square" are not intended to require absolute mathematical precision. Rather, such geometric terms allow for variations due to manufacturing or equivalent functions. For example, if an element is described as "circular" or "substantially circular," such description still encompasses components that are not precisely circular (e.g., are slightly oblong or are one of many-sided polygons).

[0068] Figure 1 is a simplified illustration of a target location T for establishing a fistula. The target location includes a first blood vessel 1 (usually a vein) and a second blood vessel 2 (usually an artery) separated by a layer 3 of interstitial fascia. Blood vessels 1 and 2 are superficially disposed beneath a layer of skin 4. Specifically, oftentimes, vein 1 is superficial relative to the surface of skin 4, and artery 2 is deeper, with the interstitial fascia layer separating the two blood vessels. Because the interstitial fascia layer 3 establishes a sliding plane between blood vessels 1, 2, and allows the blood vessels to move independently of each other, it may be necessary to fix the blood vessels before establishing an anastomosis therebetween.

[0069] Figure 2 Flow chart of a method 40 for percutaneous fistula creation according to an embodiment. Figure 3-8 , which depicts the creation of a fistula at a target location T. Although the method 40 is described as being performed using a medical device (or introducer) 110 and a catheter assembly 160, in other embodiments, the method 40 is not limited to being performed using a medical device (or introducer) 110 and a catheter assembly 160. Figure 3-8Rather, the specific instruments and devices shown in the drawings may be used to perform the process, and any suitable instruments and devices of the type shown and described herein may be used. Figure 3-5 The use of introducer 110 to create a fistula is shown, but in other embodiments, method 40 may use forceps (e.g., Fig.11 226) shown in FIG.

[0070] The method 40 includes, at 42, percutaneously inserting a medical device into a target location having a first blood vessel and a second blood vessel. The medical device can be any suitable medical device of the type shown and described herein. For example, referring to Figure 3-5 , the medical device may include an introducer 110 and / or a needle 120. As shown, the introducer 110 includes a distal tip 112 and a proximal hub 114, and defines a lumen 111 therethrough. The distal tip 112 includes an inclined surface 113, which may pierce, expand, and / or displace body tissue during insertion. In addition, the inclined surface 113 may guide the exit path of the needle 120 (see Figure 4 and 4a ) to ensure that the needle 120 is properly positioned during its deployment. In some embodiments, the proximal hub 114 may include one or more alignment marks (or indicators) 115.

[0071] Reference again Figure 3 , the introducer 110 is positioned beside the artery 2. The introducer 110 can be positioned using ultrasound guidance or other suitable visualization techniques so that it is positioned close to the artery 2 and is at a desired depth relative to the artery 2, as shown. In some embodiments, the distal tip 112 may include a radiopaque marker that can be used to measure the insertion depth. In other embodiments, the introducer 110 may include a scale mark to provide a depth indicator. The introducer 110 may also have other features to improve its echogenicity, such as a rough surface or coating. In addition, the introducer 110 is oriented so that the inclined surface 113 on the distal end 112 faces the artery 2. In order to promote the proper orientation of the introducer 110, there are visual features on the axle or marks (e.g., alignment marks 115) on the axle and / or the axle for guiding the physician. These features may be included in molded features on the pinwheel axle or ink marks on the axle and / or the axle. Therefore, in some embodiments, the method optionally includes rotating the introducer at 43 to align the inclined surface toward the blood vessel.

[0072] refer to Figure 2 The method includes deploying a fastener to a target location via a medical device at 44. The fastener is in a first configuration before deployment and in a second configuration after deployment. The fastener restricts relative movement between the first blood vessel and the second blood vessel when in the second configuration. As described above, in some embodiments, the medical device may be (or include) a needle for deploying the fastener. As described in Figure 4 As shown in FIG. 1 , in some embodiments, the medical device includes both an introducer 110 and a needle 120. After positioning the introducer 110, the curved needle 120 is advanced through the lumen 111 ( Figure 3 In some embodiments, the curved needle 120 is constructed of a resilient shape memory material, such as that commonly available under the trade name The nickel-titanium alloy of the mark is arranged so that it can pass through the linear guide 110. Therefore, the advancement of the needle causes the curvature of the needle 120 to change. In other embodiments, the curved needle 120 may be constructed of an elastic material having sufficient rigidity to maintain a linear configuration when in the cavity 111 and to return to a curved configuration after deployment. In some embodiments, when the needle 120 moves out of the cavity 111, the needle 120 is configured to deform or bend around a predetermined bending axis. In this way, when the second (or deployed configuration), the needle 120 may be directional and / or may also have a predetermined radius of curvature. Therefore, in some embodiments, the curved needle 120 has one or more alignment features, such as an elliptical shape or other means, so that it is keyed to the inner cavity 111 of the introducer 110 to ensure that when the introducer 110 is present, the surrounding artery 2 is bent in the correct orientation. The curved needle 120 is advanced using appropriate imaging guidance (such as ultrasound guidance) until it leaves the skin 4 (on the opposite side of the blood vessels 1 and 2). Figure 5 ).

[0073] In some embodiments, the fastener may be a flexible member, such as a suture, a sling, or a filament-like structure. Figure 5 , in some embodiments, the suture 130 is coupled to (or included as part of) the end of the needle 120. Thus, as the needle advances, the suture 130 (and the needle 120) surround at least a portion of each of the first blood vessel 1 and the second blood vessel 2. Similarly stated, deploying the flexible member may include wrapping (or partially wrapping) the flexible member around one or both of the blood vessels. Once the curved needle 120 has been pulled through the skin surface 4, it is cut off (or otherwise removed) from the suture 130. In some embodiments, the method includes fastening (or fixing) the first end 131 of the suture 130 to a first portion of the skin 4 outside the target location. The method may also optionally include fastening (or fixing) the second end 132 of the suture 130 to a second portion of the skin 4 outside the target location. The end of the suture (or any flexible member described herein) may be fastened to the skin by any suitable mechanism. For example, such as Figure 6 and 6a As shown, the ends of the suture may be secured using knot 133. In other embodiments, other suitable securing methods may be used, such as adhesives or mechanical fasteners.

[0074] As described above, after the fastener is deployed (i.e., when in its second configuration), the fastener restricts relative movement between the first and second blood vessels. In this way, the blood vessels can be in a fixed position for establishing an anastomosis. In other embodiments, deploying the fastener can also include moving the first and / or second blood vessels. In this way, the two blood vessels can be moved into close enough proximity to each other to facilitate percutaneous creation of a fistula. In some embodiments, the first and second blood vessels can be moved into contact with each other (directly or through a nominal interstitial tissue layer). For example, referring to Figure 6 and 6a In some embodiments, after the first end 131 of the suture 130 is secured to the skin 4, tension is applied to the suture 130. This tension and fixation holds the artery 2 and vein 1 together, as in Figure 6 This creates a suture loop 130 under tension, which holds the vein 1 and artery 2 together, as shown in FIG. Figure 6 and 6a Typically, the suture 130 is left in place for a suitable period of time, such as 1-2 weeks, so that the anastomosis has time to heal and stabilize. The suture material 130 may comprise a dissolving type of material, such as polylactic-co-glycolic acid or polyglycolic acid, or alternatively, a non-dissolving material that is later removed.

[0075] Reference again Figure 2 The method includes percutaneously creating an anastomosis between a first blood vessel and a second blood vessel at 45. The anastomosis can be created by any suitable device, such as any of the catheter assemblies disclosed, for example, in applicant's prior U.S. Patent Nos. 9,138,230; 9,439,710; 9,439,728; 9,452,015; and 9,474,562, all of which are expressly incorporated herein by reference in their entirety. As an example, Figure 7 and 8 Generally, a method for establishing an anastomosis between blood vessels 1, 2, which have been fastened together using a flexible member in a manner similar to that described above, is described. Specifically, the anastomosis is created using a catheter assembly 160 having a central lumen that can be tracked over a guidewire 180 from blood vessel 1 (typically a vein) into an adjacent blood vessel 2 (typically an artery). The catheter assembly 160 has a distal tip 161, a proximal base 162, and a sliding element 163, about which the distal tip 161 can move relative to the proximal base 162. The distal and proximal elements 161, 162 each have two parallel opposing surfaces and are separated by the sliding element 163. The opposing parallel surfaces are typically disposed at a shallow angle relative to the lumen axis, such as Figure 7As shown, to increase the surface area between them. The placement angle is generally between 15 and 45 degrees, with the preferred angle being about 23 degrees. The catheter assembly is positioned so that the sliding distal tip 161 is positioned in the blood vessel 2 and the proximal portion 162 is positioned in the blood vessel 1. With the distal element 161 in the artery 2, the distal element 161 is retracted relative to the proximal element 162. As the elements 161, 162 slide toward each other, the vessel wall is captured between the relative parallel surfaces of the elements. Energy is applied to the catheter elements to ablate the tissue captured between the elements by modifying the collagen matrix in the surrounding tissue, and the vessel wall is sealed together along the circumference. The ablated tissue between the two blood vessels establishes anastomosis between them, and the catheter is removed, leaving a completed anastomosis 13 ( Figure 8 ). The methods and inventions described herein may be utilized before or after placement and activation of a catheter, as described in more detail herein.

[0076] There are several alternative devices and methods that can be used to achieve similar results as the embodiments and methods discussed above within the parameters of the present invention. For example, Fig. 9 and 9b As shown, not as Figure 4-8 In other embodiments, suture 130 (or any other suitable flexible member) may be placed through the top or upper wall of artery 2. This approach may help prevent the tension applied by the suture from narrowing or collapsing the arterial lumen. In this case, the anastomotic catheter (see Figure 7 ) is positioned proximal or distal to suture 130.

[0077] Figure 7 Yet another variation is described, in which instead of attaching the suture 130 to the skin 4 via two separate fixing points, the suture is placed around the vein 1 through a small skin incision 15. Through the incision 15, the two free ends of the suture 130 are joined by means of a knot 133 or other suitable fastening method. This method may be indicated when the blood vessels 1, 2 are too deep and sufficient tension cannot be applied to the suture using the above method to close the blood vessels.

[0078] Although medical devices Figures 3 to 5 1 and 120, but in other embodiments, the medical device for deploying the fasteners may be any suitable medical device. For example, in some embodiments, the method 40 need not be performed using an introducer. For example, in some cases, if the blood vessels 1 and 2 are sufficiently superficial, such as Fig.11As shown, then the introducer 110 may not be necessary and a standard curved suture needle 225 may be used. In such methods, the physician may insert the distal end of the needle 225 directly through the skin 4 using the distal end of a suitable instrument 226 (e.g., forceps) for gripping and manipulating the proximal end of the needle, and manipulate the needle 225 to the indicated position around the blood vessels 1, 2. The suture 130 may then be secured in place as needed when the anastomosis is established and established.

[0079] Although the fasteners are shown and described above as flexible members, such as sutures or slings, in other embodiments, the fasteners may have any suitable rigidity. For example, in some embodiments, the fasteners may have sufficient rigidity to maintain their shape, thereby applying a force (or limiting relative movement between a first blood vessel and a second blood vessel) without being fastened (or fixed) to the skin separately. In other words, in some embodiments, the fasteners may be rings, clips, or clamps that do not have to be tied together. For example, Fig.12 According to an embodiment, a fastener 335 is shown. The fastener 335 is a ring that can be used to achieve fixation of the blood vessels 1, 2. Instead of using sutures to fasten the blood vessels, according to the methods described herein, the ring 335 can be advanced through the introducer 110 or any other suitable medical device (in Fig.12 In some embodiments, the ring 335 is made of a superelastic shape memory material (such as ) so that as it is advanced out of a medical device (e.g., an introducer), it assumes its deployed circular configuration to bend around a blood vessel. In this way, fastener 335 is a deformable member that is maintained in a first shape (e.g., linear) prior to deployment and transitions to a second shape (e.g., curved) when deployed. Ring 11 may also be made of an absorbable material (e.g., polylactic acid). In some embodiments, the leading edge 336 of the ring is beveled so that it can dissect tissue as it is advanced. Although a sharp lancet point may be used, it may be preferred to have a slightly rounded edge to prevent it from piercing one or both of the blood vessels. In some embodiments, fastener 335 has an alignment feature that helps maintain proper orientation of fastener 335 within a medical device (e.g., introducer 110) to ensure that the ring bends in the correct direction.

[0080] Although the method 40 described above includes a medical device (e.g., introducer 110, needle 120, and / or needle 225) to deploy fasteners that are separate from a catheter assembly (e.g., catheter assembly 160) that forms a communicating aperture or anastomosis between two blood vessels, in other embodiments, a single device may be used to establish an anastomosis and deploy fasteners. In addition, although the method 40 described above includes placing fasteners outside of a blood vessel, in other embodiments, the method may include fastening a blood vessel by placing the fasteners in contact with the inner sidewall of the blood vessel. For example, Fig.13 ,13a 13b shows a delivery catheter 460 and an implant clip 440 that allows for internal fixation of the vessel after the anastomosis is established. The catheter assembly 460 is capable of establishing anastomosis similar to the catheters discussed in conjunction with previously disclosed embodiments, and is also capable of deploying an implant clip 440 that is designed to clamp the vessel wall together internally. Although these two functions are described in conjunction with a single catheter 460, in other embodiments, two separate catheters may be used to achieve the same function.

[0081] The catheter assembly 460 is constructed in a manner similar to the catheter assembly 160 previously described herein, having a proximal portion 462 into which the clip 440 is placed, and a sliding distal tip 461. As described above, the distal and proximal elements have two parallel opposing surfaces between which the vessel wall can be clamped. At least one of the parallel surfaces includes a heater or other energy transfer element. Therefore, when the vessel wall is captured between the opposing parallel surfaces of the elements, energy is applied to at least one of the distal tip 461 or the proximal base 462 to ablate the tissue captured between the elements by modifying the collagen matrix in the surrounding tissue, and the vessel wall is sealed together along the circumference. The ablated tissue between the two vessels establishes anastomosis between them, and the catheter is removed, leaving a completed anastomosis 13 ( Fig.26 ). In addition to including parallel surfaces (and / or energy transfer elements), the proximal portion 462 includes a septum 464 within which the implant clip 440 can be removably disposed. The septum 464 defines a volume within the implant clip 440, maintaining and defining a side opening (or slot) 465 through which the implant clip 440 can be deployed. The septum 464 can also maintain the longitudinal and rotational orientation of the implant clip 440 before the implant clip 440 is released from the catheter assembly 460.

[0082] The catheter assembly 460 is coupled to (or includes) an actuator 470. The actuator includes a deployment element 471. As described herein, the actuator 470 is configured to deploy at least a portion of the implant clip 440 to the anastomosis 13 and also release the implant clip 440 from within the catheter assembly.

[0083] The implant clip 440 is configured to be removably disposed within the catheter assembly 460 for later deployment within the anastomosis 13 (see Fig.26 ) to fasten the side wall of the first blood vessel to the side wall of the second blood vessel. The implant clip 440 has opposing arms 441 and 442 that are generally parallel to each other when the implant is deployed. More specifically, the implant clip 440 defines a clamping volume between the first arm 441 and the second arm 442. Fig.25As shown in , when the implant clip 440 is deployed, the first arm 44 is positioned in the first blood vessel 1 and the second arm 442 is positioned in the second vessel 2. Therefore, the side wall of the first blood vessel 1 and the side wall of the second blood vessel 2 are within the clamping volume. As shown, the opposing surfaces of the first arm 461 and the second arm 462 include a set of grooves, ridges or structures 443 to improve the grip between the implant clamp and the blood vessel wall. The arms 441, 442 are deployed so that they are each generally parallel to the axis of the blood vessel in which they are deployed and apply a pinching force to the blood vessel walls to bring them close to each other. In some embodiments, the implant clip 440 is configured to be moved from a first configuration (e.g., Fig.13b ) to a second configuration (e.g. Fig.24 ). When the implant clip 440 is in the first configuration, the first arm (or portion) 441 is spaced apart from the second arm (or portion) 442 by a first distance. When the implant clip 440 is in the second configuration, the first arm (or portion) 441 is spaced apart from the second arm (or portion) 442 by a second distance. The implant clip is configured to apply a clamping force to the sidewall of the first blood vessel 1 and the sidewall of the second blood vessel 2 when the implant clip is in the first configuration. In some embodiments, if only short-term fixation is required, the arms 461, 462 may be or other resorbable materials such as polylactic acid (PLA). Deployment of mechanical fixation implants utilizes the plastic or elastic deflection of the device to ensure that the vessel wall is captured within the clamping volume.

[0084] In some embodiments, the deployment and / or flexure of the implant fixture 440 is caused by the movement of the actuator 470. As shown, the actuator 470 can be advanced into the implant and in the space between the implant arms 461, 462, such as Fig.13a As shown. The deployment element 471 on the distal end of the actuator 470 can be engaged with the feature 463 on the inner portion of the implant 460. The engagement of the deployment element 471 and these features 463 can provide a dual purpose - the first is to help the implant clip 460 deployment, and the second is to provide fixation with the vessel wall, thereby ensuring that the implant is fastened to the blood vessel after deployment. In some embodiments, the deployment element 471 may be included in the spiral protrusion on the distal end of the shaft, and the feature 463 is included in the sawtooth of the engagement spiral protrusion on the inner surface of the arm 461, 462. In other embodiments, any suitable mechanism for engagement and deployment can be utilized.

[0085] Fig.14 Flow chart of a method 50 for percutaneously creating a fistula according to an embodiment. Figure 15-26 Schematic diagram of

[0086] Method 50 is described, which depicts the use of catheter assembly 460 and implant clip 440 to create a fistula. Although method 50

[0087] Although described as being performed using the catheter assembly 460 and the implant clip 440, in other embodiments, the method 50 is not limited to Figure 15-26 Rather, the specific instruments and devices shown in the drawings may be used to perform the process, and any suitable instruments and devices of the type shown and described herein may be used. Figure 15-26 The use of a single catheter assembly 460 to create a fistula and deploy the clip 440 is shown, but in other embodiments, the method 50 may be performed using multiple separate catheter assemblies.

[0088] Figure 15-17 Adjacent blood vessels 1, 2 are shown where an anastomosis is to be established. These figures illustrate certain operations that may be performed separately from (or prior to) performing method 50. In particular, guidewire 480 is shown, which has been placed through blood vessel (or vein) 1 and into blood vessel (or artery) 2. Fig.16 In the embodiment, the sheath 482 and the dilator 481 are then placed over the guide wire 480, through the vein 1, across the fascia layer 3, and into the artery 2. Then, as Fig.17 As shown, sheath 482 and guidewire 480 are positioned to provide access to artery 2.

[0089] refer to Fig.14 The method 50 includes advancing a catheter assembly having an actuator, a distal tip, a proximal base, and an implant clip percutaneously in a distal direction within a target location at 52 until the distal tip of the catheter assembly passes through a first blood vessel and enters a second blood vessel, and the proximal base of the catheter assembly is within the first blood vessel. The catheter assembly may be, for example, the catheter assembly 460 described herein. Fig.18 As shown, catheter 460 can be advanced over guidewire 480 through sheath 482. Fig.19 As shown, the sliding distal tip 461 has been advanced into the artery 2, while the proximal portion 462 remains in the vein 1. In this way, the positioning catheter assembly 460 is established at the desired position (or target location) through the walls of the vein and artery. In some embodiments, the method may optionally include retracting the sheath 482 into the vein.

[0090] The distal tip of the catheter is then moved in a proximal direction relative to the proximal base at 53 to clamp the side wall of the first blood vessel and the side wall of the second blood vessel. Fig. 20 As shown, the distal tip 461 has been retracted to clamp tissue at the surgical site between the distal tip 461 and the proximal portion 462 of the catheter 460. Energy is then transmitted to at least one of the proximal base or the distal tip at 54 to create a communicating aperture 13 between the first and second blood vessels in the manner described above in conjunction with the catheter assembly 160 to cut, form and weld the anastomosis 13 between the blood vessels 1, 2.

[0091] In some embodiments, the method may optionally include repositioning or moving the catheter to align or position the implant clip 440 and / or catheter septum 464 in a desired position relative to the opening 13 between the blood vessels. Fig.19 , after establishing the anastomosis 13, the catheter assembly 460 has been advanced distally through the anastomosis 13 while the sheath 882 maintains position. In some embodiments, the catheter assembly 460 includes an echogenic feature 466 that is used to aid visualization during positioning of the device.

[0092] The method 50 also includes operating an actuator of the catheter assembly at 55 to deform the implant clip to move a first portion (or arm) of the implant clip outside the catheter assembly while maintaining a second portion (or arm) of the implant clip within the catheter assembly. Fig. 22 , implant clip 440 has been flexed and opened by actuator 470, so that the vessel wall and fascia can be captured in the mechanical fixing device. Specifically, the first part (or arm) 441 of implant clip 441 moves through the side opening 465 out of the catheter assembly 460. As described herein, in some embodiments, the first part 441 is deformable, to expand the size of the clamping volume, and the first part 441 is pushed outside the catheter assembly 460. As shown, the second part 442 remains fastened in the catheter assembly 460 (and / or the partition 464). For example, in some embodiments, the actuator 470 may include a holding or release element, which pushes the first arm 441 out of the catheter assembly 460 at the actuator 470, and the second arm 442 remains in place to engage the side wall of the second blood vessel (or artery) 2.

[0093] The catheter assembly is then moved in a proximal direction at 56 to position the first portion (or arm) of the implant clip in contact with the side wall of the second blood vessel. Fig.23 As shown, the catheter assembly 460 has been retracted (moved proximally) to position the implant clip 440 so that the first arm 461 is in contact with the side wall of the artery. Fig.24 In the embodiment of the present invention, after the anastomosis is formed, the catheter assembly 460 continues to move to fully engage the implant clip 440 with the vessel side wall on one side of the anastomosis for the purpose of fixing the vessel side walls together.

[0094] The method also includes manipulating the actuator to release the second portion (or arm) of the implant clip from the catheter assembly at 57 to place the second portion of the implant clip in contact with the side wall of the first blood vessel. In this way, the second arm of the implant clip can engage with the side wall of the first blood vessel. In addition, by releasing the second portion, the implant clip can return to its first configuration and apply a desired clamping force to the blood vessel side wall. Fig.25The anastomosis 13 is shown with the implant clip 440 holding the vessel wall and fascia so that the vein and artery cannot be significantly separated and the exit of the fistula remains open. Fig.26 Illustration of the anastomosis using a mechanical fixation device from different perspectives.

[0095] Therefore, although exemplary embodiments and methods according to the present invention have been shown and described, it should be understood that all terms used herein are descriptive and not limiting, and that many changes, modifications and substitutions may be made by those skilled in the art without departing from the spirit and scope of the present invention.

[0096] For example, although described as being applicable to the creation of an arteriovenous (AV) fistula, the present invention is applicable to any combination of blood vessels or tissues.

[0097] Although the actuator 470 is described as having a deployment element 471 that rotates or otherwise engages with the feature 443 of the implant clip 440, in other embodiments, the actuator may include an expandable deployment element. For example, Fig. 27 and 27a Schematic illustration of an actuator 570 for deploying and releasing an implant clip 540 is shown. The actuator 570 includes a deployment element 571 and a release element 572. The clip 540 is similar to the clip 440 described above and has a first portion (arm) 541 and a second portion (or arm) 572. In use, the actuator 570 is deployed by first expanding the deployment element 571 (e.g., Fig.27a In this way, the deployment element 571 can apply a force to the first portion 541 to deform (or move) the first portion 541 out of the catheter assembly, such as by Fig.27a BB in . During the positioning of the first portion 541 (and the clip) against the side wall of one of the blood vessels, the deployment element 571 can be maintained in its expanded configuration. When the first portion 541 is in the proper position against the side wall of the blood vessel, the deployment element 571 can be moved (e.g., proximally) to allow the implant clip to return to its first (or normally closed) configuration (not shown). The implant clip 540 can then be positioned so that the second portion 542 is in its desired position. The release element 572 can then be moved to release the implant clip into position.

Claims

1. A system for establishing a percutaneous fistula, comprising: a fastener configured to transition between a first configuration and a second configuration; an introducer configured to facilitate percutaneous deployment of the fastener to a target location having a first blood vessel and a second blood vessel, the introducer defining a lumen, at least a portion of the fastener being movably disposed within the lumen, the introducer maintaining the fastener in the first configuration when the portion of the fastener is within the lumen, the fastener being configured to transition to the second configuration when the fastener is deployed from the lumen to the target location, the fastener being configured to restrict relative movement between the first blood vessel and the second blood vessel when in the second configuration ； and a catheter assembly having a distal tip and a proximal base, the distal tip being axially movable relative to the proximal base, the proximal base and the distal tip being configured to clamp a sidewall of the first blood vessel and a sidewall of the second blood vessel and create an anastomosis between the first blood vessel and the second blood vessel; wherein the fastener comprises a deformable member having a first shape when in its first configuration, the first shape being substantially linear, the deformable member having a second shape when in its second configuration, the second shape being curved, the deformable member being configured to surround at least a portion of each of the first blood vessel and the second blood vessel when in its second configuration; as well as Wherein the deformable member is configured to clamp the first blood vessel and the second blood vessel together when in its second configuration.

2. The system of claim 1, wherein the deformable member is constructed of a shape memory material.

3. The system according to claim 1, in: The deformable member is configured to deform about a predetermined bending axis when the deformable member transitions from its first configuration to its second configuration; and The deformable member includes an alignment feature engagingly received within the lumen of the introducer, the alignment feature being aligned with the predetermined bending axis.

4. The system of claim 1, wherein the deformable member is constructed of a bioabsorbable material.

5. The system of claim 1, wherein the deformable member has a tapered tip.

6. The system according to claim 1, in: The deformable member is a needle; and The fastener includes a flexible member attached to the needle, the flexible member configured to be advanced via the needle within the target location, the flexible member configured to surround at least a portion of each of the first and second blood vessels to fasten the first blood vessel to the second blood vessel.

7. The system of claim 6, wherein the flexible member comprises one of a suture or a sling.

8. The system according to claim 1, in: The introducer includes a proximal hub and a distal tip, the distal tip including an inclined surface, the proximal hub including an indicator aligned with the inclined surface.

Images