Catheter with a distal braided termination

Abstract

Presented herein is an aspiration catheter having a braid formed from a continuous braiding process and having a braided distal tip design with a braid termination joining the strand ends. The braid termination may include a sleeve, band, crimp, or other type of connector that secures the ends of pairs of counter-wound strands to the distal circumference of the braid. The braid termination may include a radiopaque material to aid in visualization of the distal tip of the catheter during the procedure.

Description

[Technical Field]

[0001] The present invention relates generally to devices and methods for removing acute occlusions from blood vessels during intravascular medical procedures. More particularly, the present invention relates to a retrieval catheter having an expandable tip capable of retrieving an object or objects. [Background technology]

[0002] Clot retrieval aspiration catheters and devices are often used for mechanical thrombectomy to perform endovascular interventions when patients suffer from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Accessing neurovascular beds, in particular, is challenging with conventional techniques because the target vessels are small in diameter, distant from the insertion site, and highly tortuous. These catheters are often long and must follow the vascular anatomy at all its bifurcations and bends. Conventional devices often either have too large a profile, lack the deliverability and flexibility necessary to navigate particularly tortuous vessels, or are ineffective at removing clots once delivered to the target site.

[0003] Many existing designs for suction retrieval catheters, for example, are often limited to an inner diameter of 6 French, or approximately 0.068 to 0.074 inches. 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 8 French guide / 6 French sheath combination, and few would be comfortable with anything more than a 9 French guide / 7 French sheath combination.

[0004] In many existing aspiration catheters, the catheter diameter is consistent along the length of the catheter to the distal tip of the catheter. This means that once the target site is reached, the clot size is often larger than the inner diameter of the aspiration catheter and must be immediately compressed to otherwise enter the catheter port. This compression can lead to bunching up during retrieval and subsequent shearing of the clot. Tough, fibrin-rich clots can also become lodged in the tips of the fixed ports of these catheters, making them more difficult to extract. This clogging can also result in shearing, in which softer portions of the clot break away from the tougher regions of the clot.

[0005] Some aspiration catheters include a beveled opening to provide an oval opening in an attempt to reduce the likelihood of clot shearing. To further reduce the likelihood of clot shearing, aspiration catheters have been proposed that include an expandable distal end, which may or may not have a beveled opening. Summary of the Invention [Problem to be solved by the invention]

[0006] In many instances, fixed port catheters and catheters with expandable distal tips can have an underlying braid as the primary scaffold. It is desirable to shape the distal end of the catheter braid to achieve the needs during treatment while also having a scalable manufacturing process. [Means for solving the problem]

[0007] The present disclosure is generally directed to aspiration catheters having a braid formed from a continuous braiding process and having a braided distal tip design with a braid termination joining the strand ends. The braid termination may include a sleeve, band, crimp, or other type of connector that secures the ends of pairs of counter-wound strands to the distal circumference of the braid. The braid termination may include a radiopaque material to aid in visualization of the distal end of the catheter during the procedure.

[0008] An exemplary catheter may include a braid, multiple braid terminations, an inner liner, and an outer jacket. The braid may extend through a distal section of the catheter and may include clockwise and counterclockwise strands. Each of the multiple braid terminations may join a distal portion of a clockwise strand to a distal portion of a 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 may be expandable when the distal section is unconstrained and compressible when the distal section is constrained.

[0010] Each of the plurality of braid terminations may include a sleeve over a distal portion of the clockwise strands and over a distal portion of the counterclockwise strands.

[0011] The sleeve may include a crimped B-shape having a flat surface and two curved surfaces opposite the flat surface, and may further include ends terminating the curved surfaces between the distal portions of the clockwise and counterclockwise strands.

[0012] The sleeve may include a tubular shape having a lumen therethrough. A distal portion of the clockwise strand and a distal portion of the counterclockwise strand may extend within the lumen. The sleeve 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 and counterclockwise strands can each be oriented parallel to a longitudinal axis defined by the distal section of the catheter.

[0014] The distal portions of the clockwise and counterclockwise strands can each be oriented perpendicular to a longitudinal axis defined by the distal section of the catheter.

[0015] The plurality of braid terminations can 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, and each pair of distal portions can include a distal portion of a clockwise strand and a distal portion of a counterclockwise strand.

[0016] Each of the plurality of braid terminations may 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 and / or counterclockwise strands may include a radiopaque material. The clockwise and / or counterclockwise strands may include a shape memory material.

[0019] Each of the plurality of braid terminations may include a laser weld.

[0020] Each of the plurality of braid terminations may include an adhesive.

[0021] An exemplary method of constructing a catheter may include some or all of the following steps, which may be performed in various orders. The method may also include additional steps, including those yet to be developed, as will be understood by those skilled in the art. The method may include braiding clockwise and counterclockwise strands directly over a catheter liner disposed on a spool to form a braid, joining distal portions of the clockwise and counterclockwise strands to distal portions of the counterclockwise strands with braid terminations for some or all of the clockwise and counterclockwise strands, and heat-setting a distal segment of the braid to a larger diameter compared to the diameter of a proximal segment of the braid.

[0022] For some or all of the clockwise and counterclockwise strands, joining the distal portion of the clockwise strand to the distal portion of the counterclockwise strand with the braid termination may further include crimping a sleeve around the distal portion of the clockwise strand and the distal portion of the counterclockwise strand.

[0023] For some or all of the clockwise and counterclockwise strands, joining the distal portions of the clockwise strands to the distal portions of the counterclockwise strands with the braid terminations may further include sliding a sleeve over the distal portions of the clockwise and counterclockwise strands.

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

[0025] The method may further include aligning a distal portion of the clockwise strand and a distal portion of the counterclockwise strand orthogonally to a longitudinal axis of the catheter.

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

[0027] The method may further include joining a distal portion of the clockwise strand to a distal portion of the counterclockwise strand with a braid termination for some or all of the clockwise and counterclockwise strands, while the braid is directly over the 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 explanation of the drawings]

[0030] The above and further aspects of the present invention will be further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in the various drawings. The drawings are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the present invention. The figures depict one or more implementations of devices of the present invention by way of example only, and not by way of limitation. It is expected that one skilled in the art will be able to conceive and combine elements from multiple drawings to better suit the needs of a user. [Figure 1] 1 is an illustration of a distal portion of a catheter including an expandable distal segment having a braid and a braid termination, according to an aspect of the invention. [Figure 2A] 1 is an illustration of a distal portion of a catheter during a manufacturing process in which a pair of braid ends are positioned to facilitate the formation of a braid termination, according to an aspect of the present invention. [Figure 2B] 1 is an illustration of a distal portion of a catheter during manufacturing, with a sleeve attached to a pair of braided ends, according to an aspect of the present invention. [Figure 2C] 1 is an illustration of a distal portion of a catheter during a manufacturing process after excess distal extensions of strands have been removed, according to an aspect of the present invention. [Figure 3A] 1 is an illustration of a braid termination sleeve according to an aspect of the present invention. [Figure 3B] 1 is an illustration of a first exemplary braid termination on a liner, according to an embodiment of the present invention. [Figure 4] 10 is an illustration of a second exemplary braid termination on a liner, according to an embodiment of the present invention. [Figure 5] 10 is an illustration of a third exemplary braid termination on a liner, according to an embodiment of the present invention. [Figure 6A] 10 is an illustration of a fourth exemplary braid termination on a liner, according to an embodiment of the present invention. [Figure 6B]10 is an illustration of a distal portion of a braid including a braid termination configured similarly to a fourth exemplary braid termination on a liner, according to an embodiment of the present invention. [Figure 6C] 6C is an illustration of a distal portion of a catheter including the braid shown in FIG. 6B, according to an embodiment of the present invention. [Figure 7A] FIG. 10 is a perspective view of a distal portion of a braid including a fifth exemplary braid termination including bands each joining two pairs of strand ends, according to an embodiment of the present invention. [Figure 7B] 7B is a profile view of the braid shown in FIG. 7A, this view including a longer segment of the braid compared to FIG. 7A, according to an embodiment of the present invention. [Figure 8] 1 is an illustration of a braid having sections of different braid pattern densities, according to an embodiment of the present invention. [Figure 9A] 1 is an illustration of an exemplary catheter manufacturing process according to an aspect of the present invention. [Figure 9B] 1 is an illustration of an exemplary catheter manufacturing process according to an aspect of the present invention. [Figure 9C] 1 is an illustration of an exemplary catheter manufacturing process according to an aspect of the present invention. [Figure 10] FIG. 1 is a flow diagram of a method for constructing an exemplary catheter, in accordance with aspects of the present invention. [Figure 11] 1 is an illustration of an exemplary catheter-based procedure, in accordance with aspects of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention is not necessarily limited to the examples described, which may vary in configuration and details. The terms "distal" and "proximal" are used throughout the foregoing description and are intended to refer to a location and direction relative to the treating physician. Thus, "distal" or "distally" refers to a location away from or a direction away from the physician. Similarly, "proximal" or "proximally" refers to a location closer to or a direction toward the physician. Furthermore, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0032] As used herein, the terms "about" or "approximately" in connection with any numerical value or range of values ​​indicates a suitable dimensional tolerance that enables a portion of a component or a collection of components to function for its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value; for example, "about 90%" may refer to a range of values ​​of 71% to 99%.

[0033] As used herein, the terms "tubular" and "pipe / tube" are intended to be broadly construed and are not limited to structures having a right cylindrical or strictly circular cross section, or to structures having a uniform cross section along their entire length. For example, a tubular structure or tubular system is generally illustrated as a substantially right cylindrical structure. However, a tubular system may have a tapered or curved outer surface without departing from the scope of the present invention.

[0034] Some design and manufacturing considerations for braided support catheters may include, but are not limited to, effectively bonding the layers together, meeting flexibility criteria for aspiration procedures, having an atraumatic distal end for use in fragile vessels without causing significant trauma, having sufficient hoop strength in the distal portion of the catheter to resist aspiration forces without collapsing, having a structure that can be consistently and repeatably collapsed when advanced or retrieved through an outer guide and / or sheath and / or smaller vessels, and / or being able to elastically expand when deployed distally through an outer guide and / or sheath and / or when a clot is ingested for better interaction with and retention of the clot.

[0035] In some procedures, it may be desirable for the distal braid end to be atraumatic to reduce the risk of a severed braid end traumatizing the vessel. The distal end of the braid may be covered by a polymer catheter tip, but it is desirable for the polymer tip to be flexible and itself atraumatic. An atraumatic distal braid end is desirable to reduce the likelihood of the braid end puncturing or deforming the polymer tip without significantly increasing manufacturing cost or complexity. Exemplary catheters are presented herein with these design considerations in mind.

[0036] Presented herein are braid tip designs to facilitate the manufacturability of catheters with atraumatic distal braids. The catheters may also include radiopacity at the braid 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.

[0037] The braid need not be formed in separate pieces; the catheter may include one continuous braid. The braid transfer process may be easier for a continuous braid compared to a braid transfer process for a segmented braid. A continuous braided catheter manufacturing process may reduce manufacturing costs compared to a segmented braided catheter manufacturing process. Higher braid pattern densities (higher picks per inch, PPI) can potentially be more easily achieved for a continuous braid, which does not need to be transferred from one mandrel to another during manufacturing, compared to a braid segment that is transferred from one mandrel to another during manufacturing. Transferring a braid from one mandrel to another during manufacturing can be difficult if the braid grips the first mandrel too tightly to allow transfer. 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 the processed state to prevent annealing from making the material more ductile.

[0038] The designs herein can be utilized for ultra-large-caliber clot retrieval catheters with a large internal lumen and a distal funnel-shaped tip that can self-expand to a diameter larger than the diameter of the guide or sheath through which the catheter is coaxially delivered. The design can have a proximal elongate body for the catheter shaft and a distal tip with an expandable braided support structure and an outer polymer jacket to provide atraumatic relief to the tip. The braided support can be designed so that its expansion capacity is variably concentrated within the axial portion of the tip section. The braided cells can easily and repeatedly collapse for delivery and expand for good clot acceptance and resistance under suction. The tip section can have the ability to further expand beyond the free shape of the expanded, deployed configuration when capturing a clot. The catheter braid and tip design can be sufficiently flexible to navigate highly tortuous areas of the anatomy and recover its shape and maintain the inner diameter of the lumen when displaced within the vessel.

[0039] Accessing various vessels within the vasculature, whether coronary, pulmonary, or cerebral, involves well-known procedural steps and the use of numerous 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 with the devices and methods of the present invention in the following description, their function and exact configuration will not be described in detail. Additionally, while these descriptions often relate to thrombectomy treatment in intracranial arteries, the present disclosure can be adapted to other procedures and other body passageways as well.

[0040] Specific embodiments of the present invention will now be described in detail with reference to the Figures, where like reference numbers indicate functionally similar or identical elements.

[0041] 1 is a diagram 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 the distal end 114 of the catheter 100, 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 are curved in a counterclockwise direction CCW in the distal direction DD when viewed from the distal end 114 of the catheter 100, and the clockwise braid strands 150 are curved in a clockwise direction CW in the distal direction DD when viewed from the distal end 114 of the catheter 100. The distal portion of the catheter 100 may define a longitudinal axis LL.

[0042] 1 also includes a proximal or mid-section 102 of the catheter 100 located in a proximal direction PD relative to the distal section 101. The distal section 101 may be flared and have a larger inner diameter ID, at least at the distal end 114, compared to the proximal or mid-section 102. The inner diameter ID may be expandable when the distal section 101 is unconstrained. The proximal or mid-section 102 may have a larger braid pattern density (i.e., higher PPI, higher braid angle) compared to the braid pattern density of the distal section 101.

[0043] The illustrated catheter 100 includes a funnel tip design that can be configured to collapse and expand during use. The distal end of the clockwise braid strand 150, which is secured to the braid termination 130, cannot move away from the distal end of the counterclockwise braid strand 140, which is secured to the same braid termination 130. This can reduce the likelihood that the braid end may move into 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 through lateral bends of the catheter 100 when navigating tortuous vessels can apply forces to the braid strands 140, 150, and the termination 130 can prevent the braid strands 140, 150 from protruding through the outer jacket 120 due to these forces being on the braid strands 140, 150.

[0044] The outer jacket 160 may include one or more layers and may vary in composition over the length of the catheter 100. In some embodiments, the outer jacket 160 may be more flexible in the distal section 101 of the catheter compared to the more proximal section 102 of the catheter 100.

[0045] The braid termination 130 may include a radiopaque material. Visibility of the distal end 114 of the catheter 100 can be further enhanced by attaching a composite wire, such as NiTi DFT, filled with 10-40% platinum or tantalum, distal to the braid, under the outer jacket 160. The presence of a 60-90% NiTi tube on a 10-40% platinum core may allow the braid 120 to have shape-memory properties while still being visible under fluoroscopy. The NiTi DFT 20 Pt strands 140, 150 can provide a denser braid pattern (100-170 PPI) for shaft visibility in the proximal section 102, but additional radiopacity may be desirable if the braid 120 density is reduced to allow tip collapsibility for a funnel design. The radiopaque braid termination 130 can provide visibility of the distal tip 114 of the catheter 100. To enhance visibility at the distal end 114 of the catheter 100, a short length of tungsten-filled radiopaque jacket material can be added.

[0046] FIG. 2A is a view of the distal portion of catheter 100 during the manufacturing process, with the pair of distal portions 154, 144 of strands 140, 150 positioned to facilitate the formation of braid termination 130.

[0047] 2B is a view of the distal portion of catheter 100 during manufacturing, with sleeve 132 attached to the pair of distal portions 144, 154 of strands 140, 150. Sleeve 132 may be crimped to hold distal portions 144, 154 together. Additionally or alternatively, braid termination 130 may include adhesive, solder, and / or laser welds to join distal portions 144, 154 and / or secure sleeve 132 in place. Sleeve 132 may be made of a radiopaque material to facilitate visualization of the distal portion of catheter 100 near distal end 114.

[0048] FIG. 2C is a view of the distal portion of the catheter during the manufacturing process, after which excess distal extensions of distal portions 144, 154 of strands 140, 150 have been removed.

[0049] The braid 120 may include a first segment 121 extending in the proximal direction PD from a distal end of the braid 120, and the braid 120 may include a second segment 122 extending proximally from the first segment 121. The first braided segment 121 may be positioned within the distal section 101 of the catheter. The second braided section 122 may be positioned within the proximal or intermediate section of the catheter 102. The second braided segment 122 may have a greater braid pattern density than the first braided segment 121.

[0050] 3A is a diagram of a first exemplary sleeve 132 of a first exemplary braid termination 130. The first exemplary sleeve 132 has a B-shape. The B-shape has a flat surface 134 and two curved surfaces 135 opposite the flat surface 134. The sleeve 132 also has two ends 133 that terminate at the curved surfaces 135.

[0051] 3B is a diagram of a first exemplary braid termination 130 on a liner 115. The first exemplary sleeve 132 is oriented with the flat surface 134 facing outward and the curved surface 135 facing inward, such that the flat surface 134 faces the jacket 160 and the curved surface 135 faces the liner 115. Alternatively, the flat surface 134 may face inward and the curved surface 135 may 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.

[0052] The clockwise strands 150 and counterclockwise strands 140 can overlap each other at a distal braid junction 129. The distal braid junction 129 is positioned proximally relative to the sleeve 132. The distal braid junction 129 can be at a position where the clockwise strands 150 and counterclockwise strands 140 would otherwise overlap relative to the sleeve 132, according to the braid pattern of the first braid segment 121. Distal portions 143, 153 of the strands 140, 150 are parallel to a longitudinal axis LL ( FIG. 1 ) defined by the distal portion of the catheter 100. The strand ends 142, 152 are oriented distal to the B-shaped sleeve 132.

[0053] The B-shaped sleeve 132 can be manufactured by folding a flat sheet of material or by extrusion. The sleeve 132 can be of a material similar to the braid 120 to allow for easy welding to secure it in place. More preferably, the sleeve 132 is made from a radiopaque material such as platinum iridium or tungsten so that the catheter distal tip 114 is highly visible when mounted on the SS or NiTi braid 120.

[0054] The B-shaped sleeve 132 may have a width of about 0.0005 inches (inch) to about 0.002 inches and a length of about 0.006 inches to about 0.020 inches, more preferably a width of about 0.001 inches to about 0.0015 inches and a length of about 0.008 inches to about 0.012 inches. The sleeve 132 may be slid onto the strands 140, 150 after cutting the strands 140, 150 from a continuous spool, or may be crimped onto the strands 140, 150 before cutting the strands 140, 150 from a continuous spool. The B-shaped sleeve 132 may be secured in place by crimping, adhesive, welding, and / or soldering.

[0055] 4 is a diagram of a second exemplary braid termination 230 on the liner 115. The second exemplary braid termination 230 includes a second exemplary sleeve 232 having a tubular shape with a lumen 236 therethrough. The distal portions 153 of the clockwise strands 150 and the distal portions 143 of the counterclockwise strands 140 extend within the lumen 236. The distal portions 143, 153 of the strands 140, 150 are parallel to the longitudinal axis LL (FIG. 1) defined by the distal portion of the catheter 100. The strand ends 142, 152 are oriented distal to the O-shaped sleeve 232.

[0056] The sleeve 232 has a flat outer wall 234 and a flat inner wall 235. The O-shaped sleeve 232 may have a width of about 0.0005 inches to about 0.002 inches and a length of about 0.006 inches to about 0.020 inches, more preferably a width of about 0.001 inches to about 0.0015 inches and a length of about 0.008 inches to about 0.012 inches. The O-shaped sleeve 232 may be slid over the distal segments 143, 153 of the strands 140, 150 after the strands 140, 150 are cut from a continuous spool. The O-shaped sleeve 232 may be secured in place by crimping, adhesive, welding, and / or soldering.

[0057] 5 is a diagram of a third exemplary braid termination 330 on the liner 115. The third exemplary braid termination 330 includes a third exemplary sleeve 332 having a tubular shape with a lumen 336 therethrough. The distal portions 153 of the clockwise strands 150 and the distal portions 143 of the counterclockwise strands 140 extend within the lumen 336. The distal portions 143, 153 of the strands 140, 150 are parallel to the longitudinal axis LL (FIG. 1) defined by the distal portion of the catheter 100. The strand ends 142, 152 are oriented distal to the variable thickness O-shaped sleeve 132.

[0058] 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-sleeve 332 has a variable wall thickness for improved visibility under fluoroscopy. The variable thickness O-sleeve 332 may be slid over the distal segments 143, 153 of the strands 140, 150 after the strands 140, 150 are cut from a continuous spool. The variable thickness O-sleeve 232 may be secured in place by crimping, adhesive, welding, and / or soldering.

[0059] 6A is a diagram of a fourth exemplary braid termination 430 on the liner 115. The fourth exemplary braid termination 430 includes a fourth exemplary sleeve 432 having a tubular shape with a lumen 436 therethrough. The distal portions 153 of the clockwise strands 150 and the distal portions 143 of the counterclockwise strands 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 perpendicular to the longitudinal axis LL (FIG. 1) defined by the distal portion of the catheter 100. The sleeve 432 has a flat outer wall 434 and a flat inner wall 435.

[0060] 6B is a view of a distal portion of braid 120 including a braid termination 430 configured similarly to the fourth exemplary braid termination 430 on liner 115. Braid 120 shown in FIG. 6B is otherwise configured similarly to braid 120 shown in the previous figure.

[0061] The sleeve design may be oriented with the openings in a circumferential direction so that the openings more closely align with the direction of the braid strands 140 , 150 , thus allowing for an atraumatic finish to the braid termination 430 .

[0062] The braid termination 430 forms a distal hoop 125 similar to the 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 No. 17 / 518,428, filed November 3, 2021, which is incorporated herein by reference as if set forth in its entirety (see hoop 230 shown throughout U.S. Patent Application No. 17 / 518,428). The hoop 125 shown in FIG. 6B may reduce the likelihood of the braid ends 142, 152 migrating through the polymeric encapsulation of the outer jacket 160 and other polymeric encapsulations at the distal end 114 of the catheter 100 during use. Braid termination 430 may also allow braid 120 to be more easily formed continuously compared to braids having strands that are folded back at the distal end.

[0063] Figure 6C is a diagram of a distal portion of a catheter including the braid 120 shown in Figure 6B, a braid termination 430 configured similarly to the fourth exemplary braid termination 430, an inner liner 115, and an outer jacket 160 configured similarly to the outer jacket 160 shown in Figure 1. The braid 120 can be woven over the inner liner 115, and the outer jacket 160 can be applied over the braid 120 and the inner liner 115.

[0064] The atraumatic design of the fourth exemplary braid termination 430 may 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.

[0065] 7A is a perspective view of a distal portion of braid 120 and a fifth exemplary braid termination 530 including bands 532 each joining two pairs of strand ends near distal braid junction 129. Bands 532 are preferably radiopaque.

[0066] As shown, the distal portion of the braid 120 may include eight clockwise strands 150 and eight counterclockwise strands 140 that form eight pairs of strand ends near eight distal braid junctions 129. As shown, the catheter may include four bands 532 that each join two pairs of strands 140, 150 near the distal braid junctions 129.

[0067] The catheter 100 may include an even number of clockwise strands 150, an even number of counterclockwise strands 140, and half the number of bands 532 as the even number of strands 140, 150, such that each band 532 joins two pairs of strand ends. Alternatively, the catheter 100 may include a number of clockwise strands 150 that is 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, such that each band 532 joins three pairs of strand ends. Alternatively, the catheter may include a mix of bands joining only two pairs of strand ends and bands joining only three pairs of strand ends. The catheter 100 may include three bands 532, four bands 532, or five bands 532 for most catheter sizes disclosed herein. The catheter 100 may include more bands 532 for a denser braid 120 and / or a larger diameter catheter, as will be appreciated by those skilled in the art.

[0068] A circular or preferably flat braid 120 can be woven onto the liner 115 through a continuous braiding process. Flat braids are easier to laser weld to the marker bands due to increased surface area contact, but the ends of a circular braid can be flattened using a press tool to aid in the laser welding process. The distal segment 121 of the braid 120 can be flared through a heat-setting or annealing process. The braid 120 can be cut near the distal braid junction 129. A band 532 can be laser welded to the distal portion of the braid strands 140, 150 before reflow.

[0069] FIG. 7B is a profile view of the braid shown in FIG. 7A, which includes a longer section of the braid compared to FIG. 7A.

[0070] FIG. 8 is a diagram of a braid 120 divided into sections having a decreasing braid pattern density PPI and braid angle in the distal direction DD. The braid may include sections having a substantially uniform braid pattern density within those sections, and / or the braid may include sections having a gradual transition in braid pattern density. As shown, the braid 120 includes a first distal segment 121 having the lowest braid pattern density, a middle section 122 having a transitional braid pattern density, and a proximal-most section 123 having the highest braid pattern density of those shown. The distal segment may have a low braid angle θ1 near the distal end of the braid 120, and the braid angle θ2 may increase proximally. The middle segment may have a transition of proximally increasing braid angles θ2, θ3, and θ4. The braid pattern density and braid angle θ4 of the most proximal section 123 may be maintained to the proximal end of the braid 120, may increase proximally to facilitate catheter pushability, or may vary according to other design considerations as will be understood by one skilled in the art.

[0071] Braid 120 may further be considered to have sections based on an inner diameter ID. Distal segment 121 of braid 120 may be preformed into a funnel shape with an inner diameter ID that tapers proximally. Proximal section 124 of braid 120 may include intermediate section 122 and proximal-most section 123 and may have a substantially uniform inner diameter ID.

[0072] Sixteen nitinol wires in a one-to-one half-diamond pattern may be joined at the braid termination 130 at the distal end of the braid 120. Several variations on the braid pattern are possible and can be adapted to include the braid termination 130, as will be understood by those skilled in the art. For example, a herringbone braid pattern with one wire extending over and under two other wires may provide better flexibility compared to a half-diamond pattern with one wire under and one over the other. Another option is a full diamond pattern with two wires extending together under and over a group of two wires, which may provide more 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 higher stiffness and higher compressive strength, while fewer wires may provide better flexibility but lower compressive strength.

[0073] Generally, the PPI of a braid may have an inverse relationship to the expandability of a particular section of the braid 120. The distal expansion segment 121 of the braid may have a PPI that decreases distally, allowing for greater expansion capacity at the distal end of the braid 120. The second intermediate section 122 may have a PPI that decreases distally. Regions with greater PPI may have greater flexibility but limited expansion capacity. Similarly, regions with lower PPI values ​​may sacrifice hoop strength for significantly greater expansion capacity. The second intermediate section 122 may be configured to have some ability to expand to accommodate clot ingestion, preferably with less expansion than the distal segment 121. The ability of the intermediate section 122 to expand may decrease proximally to help compress an ingested clot as it moves proximally through the catheter 100. The braid in the proximal-most section 123 may be configured to facilitate pushing the catheter 100 through the vasculature and to resist expansion as a blood clot passes therethrough.

[0074] The distal-most cells 126 can have the smallest cell angle corresponding to the greatest expansion capacity. The distal-most cells can have a cell angle of about 65° to about 125°, more preferably about 110°. The braid angle of the distal expansion segment 121 can increase proximally to about 130° over the length 117 of the segment 121. The mid-section 122 can have a tubular profile with a gradually increasing proximal cell angle (e.g., from about 105° (preferably 130°) distally to about 154° proximally) and PPI (from about 40° to about 140° distally) to allow for localized expansion as the ingested clot passes through the section and is further compressed. The braid density pattern at the proximal end of the mid-section 122 can be maintained in the proximal-most braid section 123.

[0075] The braid 120 may have an expandable section with a relatively long axial length 116 (e.g., about 5 mm to 10 mm) for clot management properties, since a longer section can entrap and compress more clot. Alternatively, the length 116 can be kept short (e.g., about 1 mm to 5 mm) to improve hoop strength and trackability. A braid angle of 110° or less may provide radial expansion under compression, with lower angles providing greater expansion capabilities. Thus, the length 116 of the expansion zones 121, 122 may be adjusted by changing the distance over which an angle of 125° or less is maintained. Alternatively, the expansion zones 121, 122 may have a variable braid angle over at least a portion of the length 116.

[0076] 9A-9C are diagrams of an exemplary catheter manufacturing process. In FIG. 9A, the braid 120 is woven directly onto the liner 115 and spool 170. The braid 120 may be woven with sections of different PPIs as disclosed elsewhere herein (e.g., FIG. 8), or variations thereof as will be understood by those skilled in the art. In FIG. 9B, tape 172 is added to hold the braid 120 in place, and the braid ends are cut. A braid termination 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, the distal segment 121 of the braid 120 and the distal portion of the liner 115 may be flared by positioning the inner hole of a funnel cone 174 over the spool 170. Funnel cone 174 is shown in cross section in FIG. 9C for illustrative purposes. A tensile load can be applied to straighten braid 120 before or after braid termination 132 is added as shown in FIG. 9B, or before or after the distal portion is flared in FIG. 9C. Once flared, distal segment 121 of braid 120 can be annealed and / or heat set by laser or other methods, as will be understood by those skilled in the art. Preferably, liner 115 is shielded from excessive heat during annealing and / or heat setting.

[0077] 9C, outer jacket 160 and other features disclosed herein may be added to catheter 100. The polymer of jacket 160 and / or liner 115 may be reflowed. Spool 170 and funnel cone 174 may be removed.

[0078] 10 is a flow diagram of a method 600 for constructing an exemplary catheter. The resulting catheter may be configured similarly to catheter 100, variations thereof, and alternatives thereof disclosed elsewhere herein, as will be understood by those skilled in the art.

[0079] In step 602, clockwise and counterclockwise strands may be braided directly onto the catheter liner disposed on the spool so that the strands form a braid. The strands may be configured similarly to the exemplary strands 140, 150, variations thereof, and alternatives thereof disclosed elsewhere herein, as will be understood by one of ordinary skill in the art. The strands may be braided to have a braid pattern similar to those disclosed elsewhere herein, variations thereof, and alternatives thereof, as will be understood by one of ordinary skill in the art. Braiding the clockwise and counterclockwise strands may be performed so that the braid has a greater braid pattern density on a proximal segment of the braid compared to a braid pattern density on a distal segment of the braid.

[0080] In step 604, the distal portion of the clockwise strand may 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 may be configured similarly to the braid terminations 130, 230, 330, 430, 530, variations thereof, and alternatives thereof disclosed herein, as will be understood by those skilled in the art. A sleeve may be crimped around the distal portion of the clockwise strand and the distal portion of the counterclockwise strand. Additionally or alternatively, the sleeve may be slid over the distal portion of the clockwise strand and the distal portion of the counterclockwise strand. The distal portions of the strands may be aligned parallel and / or perpendicular to the longitudinal axis of the catheter distal section. The distal portion of the clockwise strand may 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 above the catheter liner disposed on the spool.

[0081] In step 606, the distal section of the braid may be heat-set to a larger diameter compared to the diameter of the proximal segment of the braid. The distal segment may be heat-set to a funnel shape. The distal segment may be annealed. The distal segment may be heat-set to a shape using methodologies similar to those disclosed herein for heat-setting the distal segment 121, variations thereof, and alternatives thereof, as will be understood by one of ordinary skill in the art. The shape of the distal segment may be similar to the shape of the distal segment 121, variations thereof, and alternatives thereof, as will be understood by one of ordinary skill in the art.

[0082] 11 is a diagram of a possible sequence for accessing an occlusive clot 40 using a large-bore clot retrieval catheter 100 of the design disclosed herein. The clot 40 can be accessed with the catheter 100 collapsed within a guide sheath 30 or other outer catheter for delivery. For further distal navigation with the guide sheath 30, when the vasculature 10 is too narrow and / or tortuous, the catheter 100 can be deployed for further independent movement distally. The catheter 100 can be highly flexible to allow it to navigate M1, M2, or other tortuous regions of the neurovasculature to reach the occlusive clot.

[0083] The clot retrieval catheter 100 can have a flexible elongate body 110 that functions as a shaft with a large internal diameter (which in some cases can be 0.090 inches or larger), and a distal tip section 101 with a collapsible supporting braided structure 120. The large diameter facilitates delivery of the catheter to the target site by a variety of methods. These can include over a microcatheter, over a guidewire, with a dilator / access tool, or by itself.

[0084] In most cases, the design of the collapsible funnel tip can be configured to allow the catheter 100 to be delivered (and subsequently retrieved) through commonly sized outer sheaths and guides. For example, a standard 6 Fr sheath / 8 Fr guide typically has an inner lumen of less than 0.090 inches. Thus, the tip can be designed to have a collapsed delivery outer diameter of approximately 0.086 inches. The tip can self-expand once advanced to an unconstrained position distal to the distal end 32 of the guide sheath 30, reaching an expanded outer diameter as large as approximately 0.132 inches. Because the catheter can be independently delivered to distant occlusions, the tip section 101 must be ideally designed to resist collapse due to suction forces, have excellent lateral flexibility in both the expanded and collapsed states, have an atraumatic profile to prevent snagging at vessel bifurcations, and be adaptable to allow self-sizing when the tip needs to be advanced through vessels with smaller diameters than the tip and track calcified plaque without dislodging.

[0085] In describing exemplary embodiments, technical terminology is employed for the sake of clarity. Consequently, not all possible combinations have been listed; such variations will often be apparent to those skilled in the art and are intended to fall within the scope of the following claims. Each term is intended to have its broadest meaning as understood by those skilled in the art and is intended to include all technical equivalents that operate in a similar manner to achieve a similar purpose without departing from the scope and spirit of the present invention. It should also be understood that a reference to one or more steps of a method does not preclude the presence of additional or intervening method steps between those explicitly identified steps. Similarly, some steps of a method can be performed in a different order than described herein without departing from the scope of the disclosed technology.

[0086] [Embodiment] (1) A catheter, a braid extending through the distal section of the catheter, the braid including clockwise and counterclockwise strands; a plurality of braid terminations, each joining a distal portion of a clockwise strand to a distal portion of a counterclockwise strand; an inner liner disposed within the braid; an outer jacket disposed over the braid. (2) A catheter as described in embodiment 1, wherein the 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) A catheter as described in embodiment 1, wherein each of the plurality of braided terminations includes a sleeve over the distal portion of the clockwise strand and over the distal portion of the counterclockwise strand. (4) The catheter of embodiment 3, wherein the sleeve comprises a crimped B-shape including a flat surface and two curved surfaces opposite the flat surface. (5) The catheter of embodiment 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.

[0087] (6) the sleeve comprises a tubular shape including a lumen therethrough; A catheter as described in embodiment 3, wherein the distal portion of the clockwise strand and the distal portion of the counterclockwise strand extend within the lumen. (7) The sleeve includes an outer wall and an inner wall, 7. The catheter of claim 6, wherein the outer wall is thicker than the inner wall. (8) A catheter as described in embodiment 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 embodiment 1, wherein the distal portion of the clockwise strand and the distal portion of the counterclockwise strand are each oriented perpendicular to a longitudinal axis defined by the distal section of the catheter. (10) The plurality of braid terminations 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; A catheter as described in embodiment 1, wherein each pair of distal portions includes a distal portion of a clockwise strand and a distal portion of a counterclockwise strand.

[0088] (11) A catheter as described in embodiment 1, wherein each of the plurality of braided terminal ends comprises a radiopaque material. (12) The catheter of embodiment 1, wherein the braid has a braid pattern density in the proximal section of the catheter that is greater than the braid pattern density in the distal section of the catheter. (13) The clockwise strand and / or the counterclockwise strand comprises a radiopaque material; A catheter as described in embodiment 1, wherein the clockwise strands and / or the counterclockwise strands comprise a shape memory material. (14) A catheter as described in embodiment 1, wherein each of the plurality of braided terminations includes a laser weld. (15) A catheter as described in embodiment 1, wherein each of the plurality of braided terminal ends comprises an adhesive.

[0089] (16) A method of constructing a catheter, comprising: braiding the clockwise and counterclockwise strands over a catheter liner disposed on a spool to form a braid; joining a distal portion of the clockwise strand to a distal portion of the counterclockwise strand with a braid termination for some or all of the clockwise strand and the counterclockwise strand; and heat setting a distal segment of the braid to a larger diameter compared to a diameter of a proximal segment of the braid. (17) The method of claim 16, wherein, for some or all of the clockwise and counterclockwise strands, joining the distal portion of the clockwise strand to the distal portion of the counterclockwise strand with the braid termination further comprises crimping 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 for some or all of the clockwise and counterclockwise strands, joining the distal portions of the clockwise and counterclockwise strands to the distal portions of the counterclockwise strands with the braid termination further comprises sliding a sleeve over the distal portions of the clockwise and counterclockwise strands. (19) The method of embodiment 16, further comprising aligning the distal portion of the clockwise strand and the distal portion of the counterclockwise strand parallel to a longitudinal axis of the catheter. (20) The method of embodiment 16, further comprising aligning the distal portion of the clockwise strand and the distal portion of the counterclockwise strand perpendicular to a longitudinal axis of the catheter.

Claims

1. A catheter comprising: a braid extending through the distal section of the catheter, the braid including clockwise and counterclockwise strands; a plurality of braid terminations, each joining a distal portion of a clockwise strand to a distal portion of a counterclockwise strand; an inner liner disposed within the braid; an outer jacket disposed over the braid.

2. The catheter of claim 1 , wherein the 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 over the distal portion of the clockwise strands and over the distal portion of the counterclockwise strands.

4. The catheter of claim 3 , wherein the sleeve comprises a crimped B-shape including a flat surface and two curved surfaces opposite the flat surface.

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

6. the sleeve comprises a tubular shape including a lumen therethrough; The catheter of claim 3 , wherein the distal portion of the clockwise strand and the distal portion of the counterclockwise strand extend within the lumen.

7. the sleeve includes an outer wall and an inner wall; The catheter of claim 6 , wherein the outer wall is thicker than the inner wall.

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

9. 10. The catheter of claim 1, wherein the distal portions of the clockwise strands and the counterclockwise strands are each oriented perpendicular to a longitudinal axis defined by the distal section of the catheter.

10. the plurality of braid terminations 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; The catheter of claim 1 , wherein each pair of distal portions includes a distal portion of clockwise strands and a distal portion of counterclockwise strands.

11. The catheter of claim 1 , wherein each of the plurality of braided 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 compared to a braid pattern density in the distal section of the catheter.

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

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

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

16. 1. A method of constructing a catheter, comprising: braiding the clockwise and counterclockwise strands over a catheter liner disposed on a spool to form a braid; joining a distal portion of the clockwise strand to a distal portion of the counterclockwise strand with a braid termination for some or all of the clockwise strand and the counterclockwise strand; and heat setting a distal segment of the braid to a larger diameter compared to a diameter of a proximal segment of the braid.

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

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

19. 17. The method of claim 16, further comprising aligning the distal portion of the clockwise strand and the distal portion of the counterclockwise strand parallel to a longitudinal axis of the catheter.

20. 17. The method of claim 16, further comprising aligning the distal portion of the clockwise strand and the distal portion of the counterclockwise strand orthogonally to a longitudinal axis of the catheter.

Images