Catheter with distal braid termination

Abstract

An aspiration catheter is presented having a braid formed from a continuous knitting process and having a knitted distal tip design with a braid termination that engages a strand end. The braid terminations may include cannulas, straps, curls, or other types of connectors that secure paired ends of oppositely wound strands to each other at the distal circumference of the braid. The braid terminations may include radiopaque material to help visualize the distal end of the catheter during a procedure.

Description

Technical Field

[0001] The present invention generally relates to devices and methods for removing acute blockages from blood vessels during endovascular medical treatment. More specifically, the present invention relates to a retrieval catheter having an expandable tip into which one or more objects may be retrieved. Background Art

[0002] In the case of patients suffering from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI) and pulmonary embolism (PE), clot removal aspiration catheters and devices are often used in mechanical thrombectomy for endovascular intervention. It is particularly challenging to access the neurovascular bed using conventional techniques because the target vessels are small in diameter, distal to the insertion site, and highly tortuous. These catheters are typically of great length and must follow the configuration of the vessel in all branches and windings. Conventional devices are typically too large in size, lack the deliverability and flexibility required to traverse particularly tortuous vessels, or are unable to effectively remove clots when delivered to the target site.

[0003] Many existing designs of aspiration retrieval catheters are typically limited to, for example, 6Fr or an inner diameter between approximately 0.068"-0.074". Larger sizes require the use of larger guides or sheaths, which in turn require the closure of larger femoral access holes. Most physicians prefer to use an 8Fr guide / 6Fr sheath combination, and few physicians feel comfortable exceeding a 9Fr guide / 7Fr sheath combination.

[0004] In many existing aspiration catheters, the diameter of the catheter is consistent along the length of the catheter to the distal end of the catheter. This means that once at the target site, the clot can often be larger in size than the inner diameter of the aspiration catheter, and the clot must be compressed immediately before entering the catheter tip. This compression can lead to clot bunching and subsequent shearing during retrieval. Fibrin-rich, compacted clots may also aggregate in the fixed tip end of these catheters, making them more difficult to extract. This aggregation can also lead to shearing, where softer portions of the clot break away from the more compact areas.

[0005] Some aspiration catheters include a beveled opening to provide an elliptical shaped opening in an attempt to mitigate the potential for clot shearing. Aspiration catheters including expandable distal ends have been proposed, which may or may not have a beveled opening to further mitigate the potential for clot shearing.

[0006] In many examples, fixed tip catheters and those with expandable distal tips may have an underlying braid as the primary support framework. It is desirable to form the braided distal end of the catheter to achieve the needs during treatment while also having a scalable manufacturing process. Summary of the invention

[0007] The present disclosure as a whole relates to an aspiration catheter having a braid formed by a continuous braiding process and having a braided distal end design having a braid termination that engages the ends of the strands. These braid terminations may include sleeves, bands, crimps, or other types of connectors that secure the paired ends of the relatively wound strands to each other at the distal circumference of the braid. These braid terminations may include radiopaque material to help visualize the distal end of the catheter during a procedure.

[0008] An example catheter may include a braid, a plurality of braid terminations, an inner liner, and an outer jacket. The braid may extend through a distal section of the catheter and may include clockwise strands and counterclockwise strands. The plurality of braid terminations may each join a distal portion of the clockwise strand to a distal portion of the counterclockwise strand. The inner liner may be disposed within the braid. The outer jacket may be disposed over the braid.

[0009] The inner diameter of the distal section of the catheter can be expandable when the distal portion is unconstrained and compressible when the distal portion is constrained.

[0010] The plurality of braid terminations may each include a sleeve on a distal portion of the clockwise strands and on a distal portion of the counterclockwise strands.

[0011] The sleeve may include a curled B-shape having a flat surface and two curved surfaces opposite the flat surface. The sleeve may also include an end that terminates the curved surface between the distal portion of the clockwise strand and the distal portion of the counterclockwise strand.

[0012] The cannula may include a tubular shape having a lumen therethrough. The distal portion of the clockwise strand and the distal portion of the counterclockwise strand may extend into the lumen. The cannula may have an outer wall and an inner wall. The outer wall may be thicker than the inner wall.

[0013] The distal portions of the clockwise strands and the counterclockwise strands can each be oriented parallel to a longitudinal axis defined by the distal section of the catheter.

[0014] The distal portion of the clockwise strand and the distal portion of the counterclockwise strand can each be oriented orthogonal to a longitudinal axis defined by the distal section of the catheter.

[0015] The plurality of braid terminations may include a band joining a first pair of braid distal portions, joining a second pair of braid distal portions and extending between the first pair of braid distal portions and the second pair of braid distal portions. Each pair of distal portions may include a distal portion of a clockwise strand and a distal portion of a counterclockwise strand.

[0016] The plurality of braid terminations may each include a radiopaque material.

[0017] The braid may have a greater braid pattern density in the proximal section of the catheter compared to the braid pattern density in the distal section of the catheter.

[0018] The clockwise strands and / or the counterclockwise strands may include a radiopaque material. The clockwise strands and / or the counterclockwise strands may include a shape memory material.

[0019] The plurality of braid terminations may each include a laser weld.

[0020] The plurality of braid terminations may each include an adhesive.

[0021] An example method of constructing a catheter may include some or all of the following steps, which may be performed in a variety of orders. As will be appreciated by those skilled in the relevant art, the method may also include additional steps, including those yet to be developed. The method may include: braiding clockwise strands and counterclockwise strands directly on a catheter liner disposed on a reel to form a braid; joining a distal portion of the clockwise strand to a distal portion of the counterclockwise strand via a braid termination for some or all of the clockwise strands and the counterclockwise strands; and heat setting a distal segment of the braid to a larger diameter than a diameter of a proximal segment of the braid.

[0022] Joining the distal portion of the clockwise strands to the distal portion of the counterclockwise strands through the braid termination for some or all of the clockwise and counterclockwise strands may also include crimping a sleeve around the distal portions of the clockwise and counterclockwise strands.

[0023] Joining the distal portion of the clockwise strands to the distal portion of the counterclockwise strands through the braid termination for some or all of the clockwise and counterclockwise strands may also include sliding a sleeve over the distal portion of the clockwise and counterclockwise strands.

[0024] The method may further include aligning distal portions of the clockwise strands and distal portions of the counterclockwise strands parallel to a longitudinal axis of the catheter.

[0025] The method may further include aligning distal portions of the clockwise strands and distal portions of the counterclockwise strands orthogonal to the longitudinal axis of the catheter.

[0026] Braiding the clockwise and counterclockwise strands directly onto the catheter liner disposed on the spool to form the braid may also include braiding the clockwise and counterclockwise strands to have a greater braid pattern density on a proximal segment of the braid than on a distal segment of the braid.

[0027] The method may further include joining distal portions of the clockwise strands to distal portions of the counterclockwise strands through a braid termination for some or all of the clockwise strands and the counterclockwise strands while the braid is directly on a catheter liner disposed on the spool.

[0028] The plurality of braid terminations may include laser welds.

[0029] The plurality of braid terminations may include an adhesive. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above aspects and further aspects of the present invention will be further discussed with reference to the following description and in conjunction with the accompanying drawings, in which similar numbers indicate similar structural elements and features in various figures. The accompanying drawings are not necessarily drawn to scale, but instead, emphasis is placed on illustrating the principles of the present invention. The accompanying drawings depict one or more specific implementations of the apparatus of the present invention by way of example only and not by way of limitation. It is expected that those skilled in the art will be able to conceive and combine elements from multiple drawings to better meet the needs of the user.

[0031] Figure 1 is an illustration of a distal portion of a catheter including an expandable distal section having a braid and a braid termination according to aspects of the present invention.

[0032] Figure 2A is an illustration of a distal portion of a catheter during a manufacturing step in which a pair of braid ends are positioned to facilitate formation of a braid termination in accordance with aspects of the present invention.

[0033] Figure 2B is an illustration of a distal portion of a catheter during a manufacturing step in which a sleeve is attached to a pair of braid ends in accordance with aspects of the present invention.

[0034] Figure 2C is an illustration of a distal portion of a catheter during a manufacturing step after which excess distal extensions of strands are removed in accordance with aspects of the present invention.

[0035] Figure 3A is an illustration of a sleeve of a braid termination according to aspects of the present invention.

[0036] Figure 3B is an illustration of a first example braid termination on a liner in accordance with aspects of the present invention.

[0037] Figure 4 is an illustration of a second example braid termination on a liner in accordance with aspects of the present invention.

[0038] Figure 5 is an illustration of a third example braid termination on a liner in accordance with aspects of the present invention.

[0039] Fig. 6A is an illustration of a fourth example braid termination on a liner in accordance with aspects of the present invention.

[0040] Figure 6B is an illustration of a distal portion of a braid including a braid termination configured similar to a fourth example braid termination on a liner in accordance with aspects of the present invention.

[0041] Figure 6C According to various aspects of the present invention, Figure 6B Illustration of the distal portion of a catheter showing the braid.

[0042] Fig. 7A is a perspective view illustration of a distal portion of a braid including a fifth example braid termination including bands each joining two pairs of strand ends in accordance with aspects of the present invention.

[0043] Figure 7B According to various aspects of the present invention Fig. 7A A side view illustration of the braid shown, wherein the view includes Fig. 7A Compared to longer braid segments.

[0044] Figure 8 is an illustration of a braid having sections of different braid pattern densities in accordance with aspects of the present invention.

[0045] 9A to 9C is an illustration of steps in manufacturing an example catheter according to aspects of the present invention.

[0046] Fig.10 is a flow chart of a method of constructing an example catheter according to aspects of the present invention.

[0047] Fig.11 is an illustration of a procedure utilizing an example catheter in accordance with aspects of the present invention. DETAILED DESCRIPTION

[0048] The present invention is not necessarily limited to the examples described, the configurations and details of which may vary. The terms "distal" and "proximal" are used throughout the foregoing description and refer to positions and directions relative to the treating physician. Similarly, "distal" or "toward the distal side" refers to a position away from the physician or in a direction away from the physician. Similarly, "proximal" or "toward the proximal side" refers to a position close to the physician or in a direction toward the physician. In addition, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the / said" include plural references.

[0049] As used herein, the term "about" or "approximately" for any numerical value or range indicates a suitable dimensional tolerance that allows a part or collection of components to achieve its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of ±20% of the value of the recited value, for example, "about 90%" may refer to a range of values ​​from 71% to 99%.

[0050] As used herein, the terms "tubular" and "tube" should be understood broadly and are not limited to structures that are right cylindrical or have a completely circular cross section or a uniform cross section throughout their length. For example, tubular structures or systems are generally illustrated as substantially right cylindrical structures. However, tubular systems may have tapered or curved outer surfaces without departing from the scope of the present invention.

[0051] Some design and manufacturing considerations for a braid-supported catheter may include, but are not limited to: effectively bonding the layers, meeting flexibility standards for aspiration procedures, having an atraumatic distal end for use in fragile vessels without causing substantial trauma, having sufficient hoop strength at the distal portion of the catheter to resist aspiration forces without collapsing, having a structure that is able to consistently and repeatably fold downward when advanced or retrieved through an outer guide and / or sheath and / or smaller vessels, and / or being able to elastically expand to better interact with and retain a clot when deployed distally through an outer guide and / or sheath and / or when a clot is ingested.

[0052] In some procedures, it may be desirable for the distal braid end to be atraumatic to mitigate the risk of trauma to the vessel by the cut braid end. The distal end of the braid may be covered by a polymer catheter end; however, it is desirable that the polymer end is flexible and itself atraumatic. An atraumatic distal braid end is desirable to mitigate the possibility of the braid end breaking through or deforming the polymer end without significantly increasing manufacturing cost or complexity. With these design considerations in mind, an example catheter is provided herein.

[0053] The present invention provides a braided tip design that facilitates the manufacturability of a catheter with a traumatic distal braid. The catheter may also include radiopaqueness in the braided tip. Some examples include an axial sleeve radiopaque braid termination. Some examples include a circumferential sleeve radiopaque braid termination. Some examples include a welded marker band segment braid termination. Some examples include a continuous braiding process.

[0054] The braid need not be formed as separate pieces, and the catheter may include one continuous braid. This braid transfer process may be easier for a continuous braid than for a braid formed in segments. A continuous braid catheter manufacturing process may reduce manufacturing costs compared to a segmented braid catheter manufacturing process. A higher braid pattern density (higher turns per inch, PPI) may be potentially easier to achieve for a continuous braid that does not have to be moved from one mandrel to another during manufacturing, compared to braid segments that are moved from one mandrel to another during manufacturing. If the braid clamps the first mandrel too tightly to allow transfer, it may be challenging to move the braid from one mandrel to another during manufacturing. This can be overcome by annealing or heat setting the wire to relax dislocations in the material structure; however, it may be beneficial to keep the wire in a processed state to prevent the material from being made more ductile by annealing.

[0055] The design herein can be used for an over-caliber clot retrieval catheter with a large internal lumen and a distal funnel end that can self-expand to a diameter greater than the diameter of the guide or sheath through which the coaxial delivery of the clot retrieval catheter passes. The design can have a proximal elongated body for the shaft of the catheter, and a distal end with an expansion braided support structure and an external polymer jacket to provide the end with a trauma-resistant property. The braided support can be designed so that the expansion capacity is variably concentrated in the axial portion of the terminal segment. The braid unit can easily collapse repeatedly for delivery and expansion in order to achieve good clot reception and suction resistance. The segment at the end can further expand beyond the free shape of the expanded deployment configuration when the clot is ingested. The braid and end design of the catheter can be flexible enough to traverse the highly tortuous areas of the anatomical structure, and when displaced in the blood vessel, can restore its shape to maintain the inner diameter of the lumen.

[0056] Access to various intravascular vessels (whether coronary, pulmonary or cerebral) involves well-known surgical procedures and the use of many conventional commercially available accessory products. These products, such as angiographic materials, mechanical thrombectomy devices, microcatheters and guidewires, are widely used in laboratories and medical procedures. When these products are used in conjunction with the apparatus and methods of the present invention described below, their functions and exact construction are not described in detail. In addition, although this specification is in many cases in the context of thrombectomy treatment of intracranial arteries, the present disclosure may also be applicable to other procedures and other body passages.

[0057] Specific examples of the present invention will now be described in detail with reference to the drawings, wherein like reference numerals indicate functionally similar or identical elements.

[0058] Figure 11 is an illustration of a distal portion of a catheter 100 including an expandable distal section 101 having a braid 120, a braid termination 130, an inner liner 115, and an outer jacket 160. The outer jacket 120 extends to a distal end 114 of the catheter 100, i.e., distal to the braid termination 130. The braid 120 includes counterclockwise braid strands 140 and clockwise braid strands 150 woven together to form the braid 120. The counterclockwise braid strands 140 curve in a counterclockwise direction CCW in a distal direction DD and as viewed from the distal end 114 of the catheter 100, and the clockwise braid strands 150 curve in a clockwise direction CW in a distal direction DD and as viewed from the distal end 114 of the catheter 100. The distal portion of the catheter 100 may define a longitudinal axis LL.

[0059] Figure 1 The distal portion of the catheter shown also includes a proximal or middle section 102 of the catheter 100, which is positioned in the proximal direction PD relative to the distal section 101. The distal section 101 can be open compared to the proximal or middle section 102, having a larger inner diameter ID at least at the distal end 114. When the distal section 101 is unconstrained, the inner diameter ID can be expandable. Compared with the braid pattern density of the distal section 101, the proximal or middle section 102 can have a larger braid pattern density (i.e., a higher PPI, a higher braid angle).

[0060] The illustrated catheter 100 includes a funnel-end design that can be configured to collapse and expand during use. The distal end of the clockwise braid strand 150 fixed at the braid termination 130 cannot be moved away from the distal end of the counterclockwise braid strand 140 fixed at the same braid termination 130. This can reduce the possibility that the braid end can move to a position that protrudes through the outer jacket 120 compared to a similar braid lacking a braid termination 130. Movement of the strands 140, 150 during radial expansion / compression of the tip 114 or lateral bending of the catheter 100 when passing through a tortuous vessel can apply forces to the braid strands 140, 150, and the termination 130 can inhibit the braid strands 140, 150 from protruding through the outer jacket 120 because these forces are on the braid strands 140, 150.

[0061] The outer jacket 160 can include one or more layers and can vary in composition over the length of the catheter 100. In some examples, the outer jacket 160 can be more flexible in the distal section 101 of the catheter 100 as compared to the more proximal section 102 of the catheter.

[0062] The braid termination 130 may include a radiopaque material. The visibility of the distal end 114 of the catheter 100 may be further enhanced by installing a composite wire such as NiTi DFT with 10-40% platinum or tantalum filler on the distal side of the braid, below the outer jacket 160. The presence of a 60-90% NiTi tube on a 10-40% platinum core allows the braid 120 to have shape memory properties while also having visibility under fluoroscopy. The NiTi DFT 20Pt strands 140, 150 may give a denser braid pattern (100 to 170 PPI) of proximal portion 102 axial visibility, however, increased radiopacity may be desired where the density of the braid 120 is reduced to allow for the end collapsibility of the funnel design. The radiopaque braid termination 130 may give visibility of the distal end 114 of the catheter 100. A short length of tungsten-filled radiopaque jacket material may be added to enhance visibility at the distal end 114 of the catheter 100 .

[0063] Figure 2A is an illustration of the distal portion of the catheter 100 during a manufacturing step in which a pair of distal portions 154 , 144 of the strands 140 , 150 are positioned to facilitate the formation of the braid termination 130 .

[0064] Figure 2B 1 is an illustration of the distal portion of the catheter 100 during a manufacturing step, wherein the sleeve 132 is attached to a pair of distal portions 144, 154 of the strands 140, 150. The sleeve 132 may be crimped to hold the distal portions 144, 154 together. Additionally or alternatively, the braid termination 130 may include an adhesive, solder, and / or laser welding to join the distal portions 144, 154 and / or secure the sleeve 132 in place. The sleeve 132 may be made of a radiopaque material to facilitate visualization of the distal portion of the catheter 100 near the distal end 114.

[0065] Figure 2C is an illustration of the distal portion of a catheter during a manufacturing step after which excess distal extensions of the distal portions 144, 154 of the strands 140, 150 are removed.

[0066] The braid 120 may include a first segment 121 extending from a distal end of the braid 120 in a proximal direction PD, and the braid 120 may include a second segment 122 extending from the first segment 121 in a proximal direction. The first braid segment 121 may be positioned in a distal section 101 of the catheter. The second braid segment 122 may be positioned in a proximal or middle section of the catheter 102. The second braid segment 122 may have a greater braid pattern density than the first braid segment 121.

[0067] Figure 3Ais an illustration of a first example sleeve 132 of a first example braid termination 130. The first example sleeve 132 has a B-shape. The B-shape has a flat surface 134 and two crimped surfaces 135 opposite the flat surface 134. The sleeve 132 also has two ends 133 terminating the crimped surfaces 135.

[0068] Figure 3B 1 is an illustration of a first example braid termination 130 on a liner 115. The first example sleeve 132 is oriented so that the flat surface 134 faces outward and the curved surface 135 faces inward, so that the flat surface 134 faces the jacket 160 and the curved surface 135 faces the liner 115. Alternatively, the flat surface 134 can face inward and the curved surface 135 can face outward. The end 133 of the sleeve 132 is positioned between the distal portion 153 of the clockwise strand 150 and the distal portion 143 of the counterclockwise strand 140.

[0069] The clockwise strands 150 and the counterclockwise strands 140 may overlap each other at the distal braid junction 129. The distal braid junction 129 is located in the proximal direction relative to the sleeve 132. Following the braid pattern of the first braid segment 121, the distal braid junction 129 may be a location where the clockwise strands 150 and the counterclockwise strands 140 would have overlapped if it were not for the sleeve 132. The distal portions 143, 153 of the strands 140, 150 are parallel to the longitudinal axis LL ( Figure 1 ). The strand ends 142 , 152 are oriented on the distal side of the B-shaped sleeve 132 .

[0070] The B-shaped sleeve 132 can be produced by folding a flat sheet of material or by extrusion. The sleeve 132 can have a material similar to the braid 120 to allow easy welding to fix the position. More preferably, the sleeve 132 is made of a radiopaque material such as platinum iridium or tungsten so that if installed on the SS or NiTi braid 120, the distal end 114 of the catheter is highly visible.

[0071] The B-shaped sleeve 132 may have a width of about 0.0005" (inch) to about 0.002" and a length of about 0.006" to about 0.020", more preferably about 0.001" to about 0.0015" and about 0.008" to about 0.012". The sleeve 132 may be slid over the strands 140, 150 after the strands 140, 150 are cut from the continuous spool or crimped over the strands 140, 150 before the strands 140, 150 are cut from the continuous spool. The B-shaped sleeve 132 may be secured in place by crimping, adhesives, welding, and / or solder.

[0072] Figure 41 is an illustration of a second example braid termination 230 on the liner 115. The second example braid termination 230 includes a second example sleeve 232 having a tubular shape with a lumen 236 therethrough. The distal portion 153 of the clockwise strand 150 and the distal portion 143 of the counterclockwise strand 140 extend into the lumen 236. The distal portions 143, 153 of the strands 140, 150 are parallel to the longitudinal axis LL ( Figure 1 ). The strand ends 142 , 152 are oriented on the distal side of the O-shaped sleeve 232 .

[0073] The sleeve 232 has a flat outer wall 234 and a flat inner wall 235. The O-shaped sleeve 232 can have a width of about 0.0005" to about 0.002" and a length of about 0.006" to about 0.020", more preferably a width of about 0.001" to about 0.0015" and a length of about 0.008" to about 0.012". After the strands 140, 150 are cut from the continuous spool, the O-shaped sleeve 232 can be slid over the distal segments 143, 153 of the strands 140, 150. The O-shaped sleeve 232 can be fixed in place by crimping, adhesive, welding and / or solder.

[0074] Figure 5 1 is an illustration of a third example braid termination 330 on the liner 115. The third example braid termination 330 includes a third example sleeve 332 having a tubular shape with a lumen 336 therethrough. The distal portion 153 of the clockwise strand 150 and the distal portion 143 of the counterclockwise strand 140 extend into the lumen 336. The distal portions 143, 153 of the strands 140, 150 are parallel to the longitudinal axis LL ( Figure 1 ). The strand ends 142 , 152 are oriented on the distal side of the variable thickness O-shaped sleeve 132 .

[0075] The sleeve 332 has a flat outer wall 334 and a flat inner wall 335. The outer wall 334 is thicker than the inner wall 335. The variable thickness O-shaped sleeve 332 has a variable wall thickness to enhance visibility under fluoroscopy. After the strands 140, 150 are cut from a continuous spool, the variable thickness O-shaped sleeve 332 can be slid over the distal segments 143, 153 of the strands 140, 150. The variable thickness O-shaped sleeve 232 can be fixed in place by crimping, adhesive, welding and / or solder.

[0076] Fig. 6A1 is an illustration of a fourth example braid termination 430 on a liner 115. The fourth example braid termination 430 includes a fourth example sleeve 432 having a tubular shape having a lumen 436 therethrough. The distal portion 153 of the clockwise strand 150 and the distal portion 143 of the counterclockwise strand 140 extend into the lumen 436. The strand ends 152, 142 are oriented on opposite sides of the sleeve 432 (the clockwise side of the sleeve 432 and the counterclockwise side of the sleeve 432). The distal portions 143, 153 of the strands 140, 150 are orthogonal to the longitudinal axis LL ( LL ) defined by the distal portion of the catheter 100. Figure 1 ). The sleeve 432 has a flat outer wall 434 and a flat inner wall 435.

[0077] Figure 6B is an illustration of a distal portion of braid 120 including a braid termination 430 configured similar to fourth example braid termination 430 on liner 115 . Figure 6B The illustrated braid 120 is otherwise configured similarly to the braid 120 illustrated in the previous figures.

[0078] The sleeve design may be oriented with a circumferential opening so that the opening is more closely aligned with the direction of the braid strands 140 , 150 , thereby allowing for an atraumatic finishing of the braid termination 430 .

[0079] The braid termination 430 forms a distal hoop 125 similar to a design in which each braid strand is folded back at the distal braid end so that each strand has a clockwise segment and a counterclockwise segment extending from the braid distal end 114, as described in U.S. patent application Ser. No. 117 / 518,428, filed on Nov. 3, 2021, and which is incorporated herein by reference as if set forth in its entirety (see hoop 230 shown throughout U.S. patent application Ser. No. 17 / 518,428). Figure 6B The illustrated hoop 125 can reduce the likelihood of the braid ends 142, 152 migrating during use through the polymer encapsulation of the outer jacket 160 and other polymer encapsulation at the distal end 114 of the catheter 100. The braid termination 430 can also allow the braid 120 to be more easily continuously formed compared to a braid having strands that fold back at the distal end.

[0080] Figure 6C is an illustration of the distal portion of a catheter, which includes Figure 6B The braid 120 shown, the braid termination 430 configured similarly to the fourth example braid end 430, the liner 115, and the braid termination 430 configured similarly to the fourth example braid end 430. Figure 1The outer jacket 160 of the outer jacket 160 is shown. The braid 120 can be woven on the inner liner 115, and the outer jacket 160 can be applied to the braid 120 and the inner liner 115.

[0081] The atraumatic design of the fourth example braid termination 430 can reduce the likelihood of the strand ends 142, 152 protruding through a very low durometer outer jacket 160 (such as Neusoft 42A, RezAlloy 40A, Chronoprene 40A, etc.).

[0082] Fig. 7A 1 is a perspective view illustration of a distal portion of braid 120 and a fifth example braid termination 530 including bands 532 each joining two pairs of strand ends near distal braid junction 129. Bands 532 are preferably radiopaque.

[0083] As shown, the distal portion of the braid 120 may include eight clockwise strands 150 and eight counterclockwise strands 140, thereby forming eight pairs of strand ends near eight distal braid junctions 129. As shown, the catheter may include four bands 532, each of which joins two pairs of strands 140, 150 near the distal braid junctions 129.

[0084] The catheter 100 may include an even number of clockwise strands 150, an equal even number of counterclockwise strands 140, and a number of bands 532 that is half the number of the even number of strands 140, 150, so that each band 532 engages two pairs of strand ends. Alternatively, the catheter 100 may include a number of clockwise strands 150 divisible by three, an equal number of counterclockwise strands 140, and a number of bands 532 that is one-third the number of strands 140, 150, so that each band 532 engages three pairs of strand ends. Alternatively, the catheter may include a mixture of bands that only engage two pairs of strand ends and bands that only engage three pairs of strand ends. For most catheter sizes disclosed herein, the catheter 100 may include three bands 532, four bands 532, five bands 532. As understood by those skilled in the relevant art, the catheter 100 may include more bands 532 for braids 120 of higher density and / or catheters of larger diameter.

[0085] A round or preferably flat braid 120 may be woven on the liner 115 by a continuous braiding process. A flat braid will be easier to laser weld to the marker band due to the increase in contact surface area, however, the ends of a round braid may be flattened with a pressing tool to aid in the laser welding process. The distal segment 121 of the braid 120 may be opened by a heat setting or annealing step. The braid 120 may be cut near the distal braid junction 129. The band 532 may be laser welded to the distal portion of the braid strands 140, 150 prior to reflow.

[0086] Figure 7B yes Fig. 7A A side view illustration of the braid shown, wherein the view includes Fig. 7A Compared to longer braid segments.

[0087] Figure 8 1 is a diagram of a braid 120 divided into sections with reduced braid pattern density PPI and braid angles in the distal direction DD. The braid may include sections with substantially uniform braid pattern density within those sections, and / or the braid may include sections with gradually transitioned braid pattern density. As shown, the braid 120 includes a first distal section 121 with the lowest braid pattern density, an intermediate section 122 with a transitional braid pattern density, and a nearest section 123 with the highest braid pattern density shown. The distal section has a low braid angle θ1 near the distal end of the braid 120, and the braid angle θ2 may increase toward the proximal side. The intermediate section may have a transition of braid angles θ2, θ3, and θ4 that increase toward the proximal side. The braid pattern density and braid angle θ4 of the nearest section 123 may be maintained to the proximal end of the braid 120, may increase toward the proximal side to facilitate the pushing of the catheter, or may vary according to other design considerations as understood by those skilled in the relevant art.

[0088] The braid 120 may also be considered to have segments based on an inner diameter ID. The distal segment 121 of the braid 120 may be preformed into a funnel shape having an inner diameter ID that tapers in the proximal direction. The proximal segment 124 of the braid 120 may include a middle segment 122 and a proximal-most segment 123, and may have a substantially uniform inner diameter ID.

[0089] Sixteen nitinol wires in a half diamond pattern of one wire on one wire may be joined at a braid termination 130 at the distal end of the braid 120. As will be appreciated by those skilled in the relevant art, several variations of braid patterns are possible and may be adapted to include a braid termination 130. For example, a herringbone braid pattern with one wire extending over and under two wires may provide better flexibility than a half diamond pattern of one wire on one wire. Another option is a full diamond pattern, where two wires extend together under and over a set of two wires, which may provide greater hoop strength. Another option is to reduce the number of hoops at the distal end to four or six. Another option is to increase the number of hoops at the distal end to ten or twelve. More wires may provide greater stiffness and greater compressive strength, while fewer wires may provide better flexibility but less compressive strength.

[0090] Typically, the PPI of the braid may be inversely related to the expandability of a particular section of the braid 120. The distal expandable section 121 of the braid may have a PPI that decreases in the distal direction, thereby allowing greater expansion capacity at the distal end of the braid 120. The second intermediate section 122 may have a PPI that decreases in the distal direction. Regions with larger PPIs may have greater flexibility, but limited expansion capacity. Similarly, regions with lower PPI values ​​may sacrifice hoop strength in exchange for significantly greater expansion capacity. The second intermediate section 122 may be configured to have a certain expansion capacity to accommodate clot ingestion, wherein the expansion is preferably less than the distal section 121. When a clot moves proximally through the catheter 100, the expansion capacity of the intermediate section 122 may be reduced in the proximal direction to help compress the ingested clot. The braid in the most proximal section 123 may be configured to facilitate pushing the catheter 100 through the vascular system, and may be configured to resist expansion when a clot passes through it.

[0091] The distal-most cell 126 may have a minimum cell angle corresponding to the maximum expansion capacity. The distal-most cell may have a cell angle of about 65° to about 125°, and more preferably about 110°. The braid angle of the distal expandable segment 121 may increase to about 130° proximally over the length 117 of the segment 121. The intermediate segment 122 may have a tubular profile with gradually increasing cell angles proximally (e.g., from about 105° distally (preferably 130°) and increasing to about 154° proximally) and PPI (from about 40° distally up to about 140°) to allow local expansion as an ingested clot passes through the segment and is further compressed. The braid density pattern at the proximal end of the intermediate segment 122 may be maintained in the most proximal braid segment 123.

[0092] The braid 120 may have an expandable section having a relatively long (e.g., between about 5 mm and 10 mm) axial length 116 for clot management properties, such that a longer section can ingest and compress more clots. Alternatively, the length 116 may be kept shorter (e.g., between about 1 mm and 5 mm) to improve hoop strength and trackability. A braiding angle of 110° or less can provide radial expansion under compression, with lower angles providing greater expansion capabilities. Thus, the length 116 of the expansion zones 121, 122 can be customized by changing the distance while maintaining an angle of 125° or less. Alternatively, the expansion zones 121, 122 may have a variable braiding angle over at least a portion of the length 116.

[0093] Figures 9A to 9C is a diagram of the steps in manufacturing an example catheter. Fig.9AIn the embodiment, the braid 120 is woven directly onto the liner 115 and the reel 170. The braid 120 can be woven into sections with different PPIs, such as those disclosed elsewhere herein (e.g., Figure 8 ) or variations thereof as understood by those skilled in the relevant art. Fig. 9B In, a strip 172 is added to hold the braid 120 and the braid ends are cut. A braid terminator 132 is added. The strands 140, 150 may be cut in pairs, and sleeves 132, 232, 332, 432 or bands 532 may be attached to the distal portions 143, 153 of the paired strands 140, 150. In Fig. 9C In the embodiment, the distal section 121 of the braid 120 and the distal portion of the liner 115 can be expanded by positioning the inner hole of the funnel cone 174 on the reel 170. For ease of explanation, in Fig. 9C The funnel cone 174 is illustrated in cross section in FIG. Fig. 9B As shown, before or after adding the braid termination 132, or in Fig. 9C Before or after the distal portion of the braid 120 is expanded, a tensile load may be applied to straighten the braid 120. Once expanded, the distal segment 121 of the braid 120 may be annealed and / or heat-set by a laser or other method as understood by those skilled in the relevant art. Preferably, the liner 115 is shielded during annealing and / or heat-setting to prevent overheating.

[0094] exist Fig. 9C Following the steps shown, an outer jacket 160 and other features disclosed herein may be added to the catheter 100. The polymer of the jacket 160 and / or liner 115 may be reflowed. The reel 170 and funnel cone 174 may be removed.

[0095] Fig.10 6 is a flow chart of a method 600 of constructing an example catheter. The resulting catheter may be constructed similarly to catheter 100 disclosed elsewhere herein, variations thereof, and alternatives thereof, as will be appreciated by those skilled in the relevant art.

[0096] At step 602, the clockwise strands and counterclockwise strands can be directly braided on the catheter liner disposed on the reel so that these strands form a braid. The strands can be configured to be similar to the strands 140, 150 disclosed elsewhere herein, their variations and their substitutes, as understood by those skilled in the relevant art. The strands can be braided to have a braid pattern similar to those braid patterns disclosed elsewhere herein, their variations and their substitutes, as understood by those skilled in the relevant art. Braiding the clockwise strands and counterclockwise strands can be performed so that the braid has a greater braid pattern density on the proximal segment of the braid than on the distal segment of the braid.

[0097] At step 604, the distal portion of the clockwise strand can be joined to the distal portion of the counterclockwise strand by a braid termination for some or all of the clockwise and counterclockwise strands. The braid termination can be configured to be similar to the braid terminations 130, 230, 330, 430, 530 disclosed elsewhere herein, variations thereof, and alternatives thereof, as understood by those skilled in the relevant art. The sleeve can be curled around the distal portion of the clockwise strand and the distal portion of the counterclockwise strand. Additionally or alternatively, the sleeve can slide on the distal portion of the clockwise strand and the distal portion of the counterclockwise strand. The distal portion of the strand can be aligned parallel to and / or orthogonal to the longitudinal axis of the distal portion of the catheter. The distal portion of the clockwise strand can be joined to the distal portion of the counterclockwise strand by a braid termination for some or all of the clockwise and counterclockwise strands, while the braid is directly on the catheter lining disposed on the reel.

[0098] At step 606, the distal section of the braid may be heat set to a larger diameter than the diameter of the proximal section of the braid. The distal section may be heat set to a funnel shape. The distal section may be annealed. The distal section may be heat set to a shape using similar methods as disclosed herein to heat set the distal section 121 disclosed elsewhere herein, variations thereof, and alternatives thereof, as understood by those skilled in the relevant art. The shape of the distal section may be similar to the shape of the distal section 121 disclosed elsewhere herein, variations thereof, and alternatives thereof, as understood by those skilled in the relevant art.

[0099] Fig.11 is an illustration of a possible sequence of approaching an obstructing clot 40 using a large bore clot retrieval catheter 100 of the design disclosed herein. As the catheter 100 is collapsed within a guide sheath 30 or other outer catheter for delivery, the clot 40 can be approached. When the vasculature 10 becomes too narrow and / or tortuous to navigate further distally with the guide sheath 30, the catheter 100 can be deployed to advance further distally independently. The catheter 100 can be highly flexible so that it can traverse the M1, M2 or other tortuous regions of the neurovascular vessel to reach the obstructing clot.

[0100] The clot retrieval catheter 100 may have a flexible elongated body 110 that serves as a shaft with a large inner caliber (in some cases, may be 0.090 inches or more) and a distal tip section 101 having a collapsible support braid structure 120. The large caliber facilitates delivery of the catheter to the target site by a variety of methods. These methods may include over a guidewire, over a microcatheter, with a dilator / access tool, or by itself.

[0101] In most cases, the design of the collapsible funnel tip can be configured so that the catheter 100 can be delivered (and retrieved) through a commonly sized outer sheath and guide. For example, a standard 6Fr sheath / 8Fr guide typically has an inner lumen of less than 0.090 inches. Thus, the tip can be designed with a collapsed delivery outer diameter of approximately 0.086 inches. The tip can be self-expanded once it is advanced to an unconstrained position distal to the distal end 32 of the guide sheath 30, and the expanded outer diameter can reach approximately 0.132 inches. Since the catheter can be independently delivered to a distal obstruction, the end segment 101 is ideally designed to resist collapse caused by suction forces, has excellent lateral flexibility in both the expanded and collapsed states, has an anti-traumatic profile to prevent vascular branch obstruction, and has adaptability to allow self-sizing when the tip needs to advance through a vessel having a diameter smaller than the tip and track past a calcified plaque without dislodging it.

[0102] In describing the example embodiments, terminology has been employed for the sake of clarity. Therefore, not all possible combinations are listed, and such variations are generally obvious to those skilled in the art and are intended to fall within the scope of the following claims. Without departing from the scope and spirit of the present invention, it is intended that each term contemplates its broadest meaning as understood by those skilled in the art, and includes all technical equivalents that operate in a similar manner to achieve similar purposes. It should also be understood that reference to one or more steps of a method does not exclude the presence of additional method steps or intermediate method steps between those explicitly identified steps. Similarly, some steps of the method may be performed in an order different from that described herein without departing from the scope of the disclosed technology.

Claims

1. A catheter, comprising: a braid extending through a distal section of the catheter and comprising clockwise strands and counterclockwise strands; a plurality of braid terminations, each of the plurality of braid terminations joining a distal portion of the clockwise strand to a distal portion of the counterclockwise strand; an inner lining, the inner lining being arranged in the braided fabric; and An outer jacket is arranged on the braid. 2 . The catheter of claim 1 , wherein an inner diameter of the distal section of the catheter is expandable when the distal section is unconstrained and compressible when the distal section is constrained. 3 . The catheter of claim 1 , wherein the plurality of braid terminations each include a sleeve on the distal portion of the clockwise strand and on the distal portion of the counterclockwise strand. 4 . The catheter of claim 3 , wherein the sleeve comprises a curled B-shape comprising a flat surface and two curved surfaces opposite the flat surface.

5. The catheter of claim 4, wherein the sleeve further comprises an end portion terminating the curved surface between the distal portion of the clockwise strand and the distal portion of the counterclockwise strand.

6. The catheter according to claim 3, wherein the cannula comprises a tubular shape including a lumen therethrough, and Wherein the distal portion of the clockwise strand and the distal portion of the counterclockwise strand extend into the lumen.

7. The catheter according to claim 6, wherein the sleeve comprises an outer wall and an inner wall, and The outer wall is thicker than the inner wall.

8. The catheter of claim 1, wherein the distal portion of the clockwise strand and the distal portion of the counterclockwise strand are each oriented parallel to a longitudinal axis defined by the distal section of the catheter.

9. The catheter of claim 1, wherein the distal portion of the clockwise strand and the distal portion of the counterclockwise strand are each oriented orthogonal to a longitudinal axis defined by the distal section of the catheter.

10. The catheter according to claim 1, wherein the plurality of braid terminations include a band engaging a first pair of braid distal portions, engaging a second pair of braid distal portions, and extending between the first pair of braid distal portions and the second pair of braid distal portions, and Each pair of distal portions includes a distal portion of a clockwise strand and a distal portion of a counterclockwise strand.

11. The catheter of claim 1 , wherein each of the plurality of braid terminations comprises a radiopaque material. 12 . The catheter of claim 1 , wherein the braid has a greater braid pattern density in a proximal section of the catheter than in the distal section of the catheter.

13. The catheter according to claim 1, wherein the clockwise strand and / or the counterclockwise strand comprises a radiopaque material, and Wherein the clockwise strands and / or the counterclockwise strands comprise shape memory material.

14. The catheter of claim 1, wherein each of the plurality of braid terminations comprises a laser weld.

15. The catheter of claim 1, wherein each of the plurality of braid terminations comprises an adhesive.

16. A method of constructing a catheter, the method comprising: braiding the clockwise strands and the counterclockwise strands directly onto a catheter liner disposed on a reel to form a braid; joining distal portions of the clockwise strands to distal portions of the counterclockwise strands via braid terminations for some or all of the clockwise strands and the counterclockwise strands; as well as The distal section of the braid is heat set to a larger diameter than the diameter of the proximal section of the braid.

17. The method of claim 16, wherein joining the distal portion of the clockwise strand to the distal portion of the counterclockwise strand via the braid termination for some or all of the clockwise strand and the counterclockwise strand further comprises curling a sleeve around the distal portion of the clockwise strand and the distal portion of the counterclockwise strand.

18. The method of claim 16, wherein joining the distal portion of the clockwise strand to the distal portion of the counterclockwise strand via the braid termination for some or all of the clockwise strand and the counterclockwise strand further comprises sliding a sleeve over the distal portion of the clockwise strand and the distal portion of the counterclockwise strand.

19. The method according to claim 16, further comprising: The distal portion of the clockwise strand and the distal portion of the counterclockwise strand are aligned parallel to a longitudinal axis of the catheter.

20. The method according to claim 16, further comprising: The distal portion of the clockwise strand and the distal portion of the counterclockwise strand are aligned orthogonal to a longitudinal axis of the catheter.

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