Obstacle removal system

Abstract

An obstruction removal system is provided for capturing and removing obstructions, such as blood clots, from the vasculature. The obstruction removal system may include one or more engagement members connected to an elongate member, for example, at a distal end of the elongate member. The engagement members may have an asymmetric body shape, such as a "teardrop" shape, and / or an asymmetric cell configuration between their proximal and distal portions. The engagement members may be comprised of multiple struts. One or more radiopaque markers may be connected to at least one strut having a "dogbone" shape. A mesh structure may be disposed on the interior or exterior of the engagement members to function as a filter. A support wire may be disposed internally to assist in maintaining the engagement members open. When multiple engagement members are used, each engagement member may be a different size.

Description

Technical Field

[0001] (Related Application) This application claims priority based on U.S. Provisional Application Serial No. 63 / 227,669, entitled Obstacle Removal System, filed on July 30, 2021, the entire contents of which are incorporated herein by reference.

Background Art

[0002] Described herein are devices for capturing and removing obstacles such as clots or other substances from the vascular system, as well as systems and methods related to such devices for delivering the device to a target region within the vascular system.

[0003] Accumulation of thrombus in the vascular system leads to the formation of clots. Once a clot is formed, the blood supply to the downstream region of the vascular system is restricted. The presence of thrombus in the neurovascular system can lead to stroke.

[0004] There is a need for an obstacle removal device that facilitates maximum mechanical capture of thrombus while limiting the risk of endothelial ablation caused by high friction between the device and the vessel wall, and reduces the likelihood that fragmented mass will remain in the vascular system.

Brief Description of Drawings

[0005] These and other aspects, features and advantages in which embodiments of the present invention are possible will become apparent and clear from the following description of embodiments of the present invention.

[0006] [Figure 1] Fig. 1 is a side view of an engaging member according to an exemplary embodiment.

[0007] [Figure 2] Fig. 2 is a side view of an engaging member according to an exemplary embodiment.

[0008] [Figure 3A]Figure 3A is a side view of a plurality of connected engaging members according to an exemplary embodiment.

[0009] [Figure 3B] Figure 3B is a side view of a plurality of connected engaging members according to an exemplary embodiment.

[0010] [Figure 4] Figure 4 is a plan view of the strut pattern of the engaging member according to an exemplary embodiment.

[0011] [Figure 5] Figure 4 is a plan view of the strut pattern of the engaging member according to an exemplary embodiment.

[0012] [Figure 6] Figure 6 is an enlarged view showing a structure for holding a radiopaque marker according to an exemplary embodiment.

[0013] [Figure 7] Figure 7 is an enlarged view showing a structure for holding a radiopaque marker according to an exemplary embodiment.

[0014] [Figure 8] Figure 8 is an enlarged view showing a radiopaque marker according to an exemplary embodiment.

[0015] [Figure 9] Figure 9 is an enlarged view showing a radiopaque marker according to an exemplary embodiment.

[0016] [Figure 10] Figure 10 is an enlarged view showing a radiopaque marker according to an exemplary embodiment.

[0017] [Figure 11] Figure 11 is an enlarged view of a radiopaque marker provided at the distal end of an engaging member according to an exemplary embodiment.

[0018] [Figure 12] FIG. 12 is a side view of a process for producing the radiopaque marker of FIG. 11 according to an exemplary embodiment.

[0019] [Figure 13] FIG. 13 is a side view of a process for producing the radiopaque marker of FIG. 11 according to an exemplary embodiment.

[0020] [Figure 14] FIG. 14 is a side view of a process for producing the radiopaque marker of FIG. 11 according to an exemplary embodiment.

[0021] [Figure 15] FIG. 15 is a side view of a process for producing the radiopaque marker of FIG. 11 according to an exemplary embodiment.

[0022] [Figure 16] FIG. 16 is a side view of an engagement member having a mesh structure inside thereof according to an exemplary embodiment.

[0023] [Figure 17] FIG. 17 is a side view of an engagement member having a mesh structure inside thereof according to an exemplary embodiment.

[0024] [Figure 18] FIG. 18 is a side view of an engagement member having a mesh structure between a plurality of engagement members according to an exemplary embodiment.

[0025] [Figure 19] FIG. 19 is a side view of an engagement member having a mesh structure engagement member behind it according to an exemplary embodiment.

[0026] [Figure 20] FIG. 20 is a side view of a mesh structure according to an exemplary embodiment.

[0027] [Figure 21] Figure 21 is a side view of a mesh structure according to an exemplary embodiment.

[0028] [Figure 22] Figure 22 is a side view of a mesh structure according to an exemplary embodiment.

[0029] [Figure 23] Figure 23 is a side view of an engaging member having a support wire inside according to an exemplary embodiment.

[0030] [Figure 24] Figure 24 is a side view of an engaging member having a support wire inside according to an exemplary embodiment.

[0031] [Figure 25A] Figure 25A is a side view of the first step for creating an engaging member according to an exemplary embodiment.

[0032] [Figure 25A] Figure 25A is a side view of the second step for creating an engaging member according to an exemplary embodiment.

[0033] [Figure 25A] Figure 25A is a side view of the third step for creating an engaging member according to an exemplary embodiment. [Overview of the project]

[0034] This specification describes an obstruction removal device that makes thrombi more easily captured mechanically while limiting the risk of endothelial abrasion caused by high friction between the device and the vessel wall, and reducing the likelihood of fragmented clumps remaining in the vascular system.

[0035] In one embodiment, the obstacle removal device may include an elongated member connected at or near the distal end of one or more engaging members. The one or more engaging members may have a compressed configuration when sheathed and / or constrained within the delivery device, and an expanded configuration when not sheathed and / or unconstrained.

[0036] In one exemplary embodiment, only one engaging member may be directly or indirectly connected to the elongated member, such as at the distal end of the elongated member. In another exemplary embodiment, multiple engaging members (e.g., two, three, four, five, six, seven or more engaging members) may be directly or indirectly connected to the elongated member. In embodiments having multiple engaging members, only one of the engaging members, or one or more engaging members, may be connected to the elongated member.

[0037] In one exemplary embodiment, one or more engaging members may be positioned and connected on the wire or distal portion of the elongated member. In some exemplary embodiments, the proximal and distal ends of each engaging member may be connected to one another via connecting links such that each engaging member is rotatable relative to each other.

[0038] In one exemplary embodiment, one or more of the multiple engaging members may have different widths or diameters. In one exemplary embodiment, the width or diameter of each engaging member may decrease between the proximal and distal ends of the obstacle removal system.

[0039] In one exemplary embodiment, one or more engaging members may each have a plurality of struts defining a plurality of cells or openings when the one or more engaging members are expanded from a radially compressed configuration to a radially expanded configuration. The one or more engaging members may be formed from nitinol or a similar material and may be laser-cut from a tube or panel to achieve a desired contour shape.

[0040] In one exemplary embodiment, one or more engaging members may have an asymmetrical body shape and / or an asymmetrical cell configuration between the proximal and distal ends of the engaging member. One or more engaging members may have an overall "teardrop" shape, with their distal end expanding to a relatively large diameter in the radial direction and then tapering to the proximal end over the remaining proximal length.

[0041] In an exemplary embodiment in which each engaging member is composed of multiple struts, the struts may be tapered overall such that their width decreases towards the center of the engaging member. Therefore, the proximal struts may be tapered, becoming thicker near the center, in order to increase longitudinal rigidity without increasing radial force or follow force when tension is applied.

[0042] In one exemplary embodiment, one or more engaging members may include one or more radiopaque markers positioned around at least a portion of one or more struts. One or more of the struts may include one or more structural features or shapes that assist in holding the radiopaque markers in place, such as a "dogbone" strut shape having a central portion, a first projection extending distally from the central portion, and a second projection extending proximal to the central portion. The corners of the central portion may include protrusions such as bumps or ridges that function as stoppers to prevent the radiopaque markers from sliding off the struts.

[0043] In one exemplary embodiment, the mesh structure may be located inside the engaging member or outside the engaging member, adjacent to the engaging member, and functions as a filter for capturing small pieces of the embolus. The mesh structure may consist of a single braided wire or multiple braided wires.

[0044] In one exemplary embodiment, the engaging member may include one or more support wires. The one or more support wires can support the engaging member in its extended configuration.

[0045] In one exemplary embodiment, the thrombus-capturing engagement portion comprises a plurality of open cells and has a radially compressed configuration and a radially expanded configuration, the radially expanded shape forming a longitudinally asymmetric shape having a distal region with a larger diameter than the intermediate and proximal regions.

[0046] A method for removing an obstacle may include advancing one or more engaging members from the delivery catheter and engaging one or more engaging members with the obstacle.

[0047] A method for manufacturing an obstacle removal system may include forming one or more engaging members and connecting at least one of the one or more engaging members to an elongated member.

[0048] Another method for manufacturing an obstacle removal system may include providing an engaging member consisting of a plurality of struts, and coating one or more of the struts, or around them, with a radiopaque material. Embodiment

[0049] Specific embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention may be carried out in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these exemplary embodiments are provided to make this disclosure thorough and complete and to fully convey the scope of the invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the accompanying drawings are not intended to limit the invention. In the drawings, similar numbers refer to similar elements. Although different embodiments are described, features of each embodiment can be used interchangeably with other described embodiments. In other words, any of the features of each embodiment can be mixed and combined with each other, and embodiments should not necessarily be strictly construed as including only the illustrated or described features.

[0050] For the purposes of the technical terms described below, the terms blood clot, thrombus, embolus, and obstruction can be used synonymously. While an obstruction removal device is described, it can also be used to capture blood clots, thrombi, embolus, foreign bodies, or other substances. Engaging members on the device can engage with blood clots, thrombi, embolus, foreign bodies, obstructions, or other substances.

[0051] In this specification, when referring to a value, the terms "about" or "around" may be understood to mean within plus or minus 5% of the stated value.

[0052] The present invention may comprise an obstacle removal system comprising one or more engaging structures, such as one or more engaging members. The engaging structures, such as engaging members, are generally considered to be expandable structures having multiple openings, cells, or spaces of a size that, when in an expanded position, allow blood clots or similar components to engage with and / or enter the interior of the structure.

[0053] At least one of the engaging members may be connected directly or indirectly to the elongated member. One engaging member may be connected to the elongated member (e.g., the distal end of the elongated member), or multiple engaging members may be connected to the elongated member.

[0054] When multiple engaging members are used, adjacent engaging members may be connected to each other via connecting links so that each engaging member can rotate relative to the other engaging members. Such a configuration can provide a degree of freedom of movement and enhance the blood clot retrieval process.

[0055] Each engaging member may include multiple struts that define multiple cells or openings when the engaging member is expanded and radially enlarged. The engaging member may have an asymmetrical body shape and an asymmetrical cell configuration between its proximal and distal ends. Thus, the first portion of the engaging member may have a different size and / or cell size / layout than the second portion of the engaging member (for example, the distal half of the engaging member may have a different size and / or cell size / layout than the proximal half of the engaging member).

[0056] When multiple engaging members are used, one or more engaging members may have a different size from the other one or more engaging members. Therefore, the present invention may include multiple engaging members, each having a different size (e.g., width or diameter). The size of each engaging member may decrease between the proximal and distal ends of the obstacle removal system. Pairs of engaging members of similar size may be grouped together, so that each subsequent pair has a different size from the previous pair.

[0057] The cells or openings of the engaging member may have a lower porosity (i.e., smaller cell size) at the distal end of the engaging member and a generally higher porosity (i.e., larger cell size) at the intermediate end of the engaging member. The generally higher porosity at the intermediate end may help the blood clot enter and be removed by the engaging member. Reducing the porosity at the distal end of the engaging member may prevent the blood clot from moving through the engaging member, potentially leading to retrieval failure.

[0058] The strut itself may have sections with different widths. The strut may be tapered overall so that its width decreases towards the middle of the engaging member (i.e., the strut may decrease in width from a first width at the proximal part of the engaging member towards the middle). Therefore, the strut near the center may be made thicker to increase rigidity when tension is applied. The distal strut may be tapered in the opposite direction to the taper of the proximal strut.

[0059] One or more engaging members may include one or more radiopaque markers. Each radiopaque marker may consist of a wire wound around the strut, a wire coil, a wound ribbon, a folded sheet around the strut, a hypo tube placed around the strut, beads, etc. Various methods for attaching the radiopaque markers to the strut include, but are not limited to, adhesive, welding, and melting.

[0060] The strut may include structural features or shapes useful for holding a radiopaque marker on the strut. One or more struts may include a "dogbone" shape having regions at their proximal and distal ends that are wider than adjacent regions of the strut. Projections at both ends of the central part of the strut can prevent the radiopaque marker from sliding off to the proximal or distal side.

[0061] The obstruction removal system may include a mesh structure capable of functioning as a filter to capture embolic fragments to prevent loss during the blood clot recovery process. The mesh structure may be at least partially within the engaging member, or it may be outside the engaging member but adjacent to it. The mesh structure may consist of a single braided wire, or it may consist of multiple braided wires of various shapes.

[0062] The obstacle removal system may include within one or more engagement members one or more structures that assist in expansion and prevent collapse, particularly when passing through tortuous vessels. The one or more structures may include one or more support wires disposed within one or more engagement members. The one or more support wires may be heat-set into a wide range of shapes, including a helical shape or a plurality of concentric ring shapes.

[0063] Specific examples of the embodiments are described below. However, it should be understood that any of the features in the embodiments can be mixed and combined with each other in any combination. Therefore, the present invention should not be limited to these embodiments, and a wider range of combinations are possible.

[0064] Figures 1 and 2 show engaging members 100 that may be used in various embodiments of the obstacle removal device 101. The systems and methods shown and / or described herein are available with various obstacle removal devices 101, and the exemplary embodiments shown in the figures should not be construed as limiting the scope. The systems and methods shown and / or described herein are available in combination with obstacle removal devices 101 shown and / or described, for example, in U.S. Patent Nos. 1,0729455, 1,0722254, 1,0709466, 9833252, 9770251, 9211132, and U.S. Patent Publication No. 2019 / 0046210, all of which are incorporated herein by reference in their entirety.

[0065] In one exemplary embodiment shown in the figure, the obstruction removal device 101 may include one or more distal engaging members 100 capable of engaging with thrombi or similar substances that may accumulate in the vascular system. The engaging members 100 can be deployed adjacent to the thrombus or embolus and then retracted proximal to capture the thrombus or embolus within the engaging members 100. The engaging members 100 may then be retracted further proximal into the delivery device 105 and removed from the patient.

[0066] The systems and methods shown and / or described herein are available with various delivery devices 105, and the exemplary embodiments shown in the figures should not be construed as limiting the scope. In non-limiting examples, exemplary embodiments of the delivery device 105 include, but are not limited to, a catheter, sheath, or tubular jacket having a continuous passage that allows passage of the obstacle removal device 101, and may include various tubular medical delivery devices.

[0067] As shown in Figure 1, an exemplary embodiment of the obstacle removal device 101 may include an elongated member 103 connected at or near the distal end of one or more engaging members 100. In some embodiments, the elongated member 103 may be a solid member. In other embodiments, the elongated member 103 may be tubular. For example, the elongated member 103 may include a lumen extending through at least a portion of its length. In some embodiments, the elongated member 103 may have a continuous lumen penetrating the elongated member 103, thereby functioning like a catheter (for example, it can be used as a conduit for an item to be deployed later). The elongated member 103 can be considered a pusher as it may be used to position the obstacle removal device 101 itself. An overhead delivery device 105 may be positioned above the elongated member 103 so as to allow both the elongated member 103 and one or more engaging members 100 to advance from and / or be retracted into the delivery device 105.

[0068] Each engaging member 100 has a collapsible configuration when sheathed within the delivery device 105, and can have an expanded configuration as shown in Figures 1 and 2 when not sheathed. Each engaging member 100 may be self-collapsed and self-expandable depending on whether an external force is applied to restrain it (as when sheathed within the delivery device 105) or whether no restraining force exists (as when not sheathed). Each engaging member 100 may be made of a shape memory material (e.g., nitinol) and can be heat-set to impart expandable shape memory. This allows the engaging member 100 to take on an expanded shape when released from the delivery device 105.

[0069] In one embodiment, only one engaging member 100 may be located at the distal end of the elongated member 103 and connected (directly or indirectly). In another embodiment, as shown in Figure 3A, multiple engaging members 100 may be located at the distal end of the elongated member 103 (note that although the elongated member 103 itself is not shown in Figure 3A, it may be connected to at least the nearest engaging member 100, and in some embodiments, it may be connected to multiple engaging members 100).

[0070] All of the engagement members 100 may be positioned and connected on the wire or distal portion of the elongated member 103. Alternatively, the proximal and distal ends of each engagement member 100 may be connected to one another via a connecting link (for example, an axis or pin having a flared end positioned within each engagement member 100). One advantage of the latter configuration is that each engagement member 100 can rotate independently of the other engagement members 100. This independent rotation allows each engagement member 100 to move with some degree of freedom, which can improve the blood clot retrieval procedure.

[0071] In some exemplary embodiments, the connecting link allows for some degree of sliding movement relative to each engaging member 100 (for example, a shaft or pin with a flared end is slightly longer than the retaining structure), thereby further improving the independence of movement of each engaging member 100. Further information relating to such connecting structures is provided in U.S. Patent No. 9,211,132 (which is incorporated herein by reference in its entirety).

[0072] Each of the engaging members 100 may have a plurality of struts 102 that define a plurality of cells or openings 104A to 104D when the engaging member 100 is expanded from a radially compressed configuration to a radially expanded configuration. The engaging members 100 can be formed from nitinol or a similar material and may be laser-cut from a tube or panel to achieve a desired contour shape. Other materials and other cutting and / or machining processes may also be included within the scope of the present invention.

[0073] In one embodiment, the engaging member 100 may be configured to have an asymmetrical body shape and an asymmetrical (i.e., longitudinally asymmetrical) cell configuration between the proximal and distal portions of the engaging member 100. In other words, the first portion of the engaging member 100 does not have to have the same size or cell size / layout as the second portion of the engaging member 100. In one exemplary embodiment, the distal half of the engaging member 100 may have a different size or cell size / layout than the proximal half of the engaging member 100. In another exemplary embodiment, the distal quarter of the engaging member 100 may have a different size or cell size / layout than the proximal three-quarters of the engaging member 100. Various other configurations can be utilized in different embodiments to suit different applications.

[0074] Figures 3A and 3B show multiple engaging members 100 connected to one another. Figure 3A shows an exemplary embodiment having four engaging members 100. Figure 3B shows an exemplary embodiment having six engaging members 100. It should be understood that the number of engaging members 100 shown in the various exemplary embodiments shown in the figures does not mean limiting the range, as more or fewer engaging members 100 can be used in different embodiments to suit different applications. For example, some exemplary embodiments may have fewer than three engaging members 100, five engaging members 100, or six or more engaging members 100.

[0075] In the illustrated exemplary embodiment, the engaging members 100 are arranged linearly, and each engaging member 100 is shown in an unfolded configuration. It should be understood that during delivery and / or unfolding, the engaging members 100 may not be arranged linearly, such as when passing through tortuous blood vessels.

[0076] Figure 3A shows an exemplary embodiment in which the engaging members 100 are substantially the same size. However, in some embodiments, one or more engaging members 100 may be larger or smaller than one or more of the remaining engaging members 100. Figure 3B shows an exemplary embodiment in which the width or diameter of the engaging members 100 decreases between the proximal and distal ends. In some embodiments, the reverse configuration may be used in which the width or diameter of the engaging members 100 increases between the proximal and distal ends. Thus, the proximal engaging member 100 may be wider or larger in diameter than the distal engaging member 100, and the central engaging member 100 between the proximal and distal engaging members 100 may be wider or larger in diameter than the distal engaging member 100 and narrower in width or diameter than the proximal engaging member 100.

[0077] Continuing to refer to Figure 3B, it can be seen that the multiple engaging members 100 may include pairs of engaging members 100 having substantially similar widths or diameters. In the illustrated exemplary embodiment, the distal pair of engaging members 100 is wider or larger in diameter than the central pair of engaging members 100, and the central pair of engaging members 100 is wider or larger in diameter than the proximal pair of engaging members 100. In different embodiments, various other configurations in which the width or diameter increases or decreases may be utilized. For example, in some embodiments, the width or diameter of the engaging members 100 may decrease and then increase, and vice versa.

[0078] The body shape and cells of the radially expanded engagement member 100 are best shown in Figures 1 and 2, while Figure 4 and Figure 5, showing a slightly modified design, show the engagement member 100 in a flattened configuration (i.e., as if the engagement member 100 were radially compressed, cut open, and laid flat). Figures 4 and 5 can be considered as shapes formed during the manufacturing process of the engagement member 100 (e.g., a laser-cut sheet), and as shapes prior to the manufacturing process taken to radially expand that shape.

[0079] As can be seen from these figures, the main body shape of the engaging member 100 may have an overall "teardrop" shape, where its distal end 113 expands to a relatively large diameter in the radial direction, and then tapers to the proximal end 111 over the remaining proximal length. In one embodiment, the strut 102 of the engaging member 100 expands to its maximum distal diameter in the first quarter of its length from the distal end, and then tapers in diameter over the remaining three-quarters of its length in the proximal direction. The desired expanded shape can be achieved, for example, by shaping or heat-setting the engaging member on a mandrel that forces it to take on the desired shape and diameter during expansion.

[0080] In one exemplary embodiment, the engaging member 100 may have a length of about 3 mm when expanded, and a tapered shape in which the radial diameter decreases towards the proximal end, with a maximum radial diameter of about 2 mm along a length of about 1 mm from the distal end. In another exemplary embodiment, the engaging member 100 may have a length of about 6 mm when expanded, and a tapered shape in which the radial diameter decreases towards the proximal end, with a maximum radial diameter of about 3 mm along a length of about 2 mm. Thus, from several embodiments, it should be understood that the maximum diameter of the engaging member 100 is equal to about 25% to 75% of its length. In one exemplary embodiment, the maximum radial diameter of the engaging member 100 may be equal to about 66% of its length. In another exemplary embodiment, the maximum diameter of the engaging member may be equal to about 50% of its length.

[0081] As shown in the figure, the cells 104C that constitute the open space of the engaging member 100 may be configured to have a generally low porosity (i.e., smaller cell size) in the distal part of the engaging member 100 and a generally high porosity (i.e., larger cell size) in the intermediate part. In some embodiments, the generally high porosity of the cells 104C may also be present in the proximal part. Because the porosity in the intermediate part is generally high, blood clots may easily enter the engaging member 100.

[0082] By reducing the void ratio in the distal portion, blood clots become less likely to move through the engaging member 100, potentially increasing the chances of successful retrieval. In addition, this cell and strut pattern may allow for greater flexibility in the middle portion of the engaging member 100, so that the engaging member 100 can bend well to conform to the curves within the blood vessel, while being less likely to be negatively affected or twisted, thus reducing its ability to capture and release distal blood clots.

[0083] A larger proximal porosity (i.e., larger proximal cells) results in a smaller strut area along the proximal portion of the device, thus reducing the resistance to crushing when the engaging member 100 is retracted. Furthermore, an overall tapered shape (for example, the overall diameter of the engaging member 100 increases from the proximal end to the distal end) may allow for smoother expansion and crushing of the engaging member 100 during delivery and / or deployment from the delivery device 105, thereby assisting in blood clot retrieval procedures.

[0084] The void ratio described above can be adjusted by increasing or decreasing the number and / or size of each cell. As an example, in the patterns shown in Figures 1 to 3, the engaging member 100 may have a length of approximately 3 mm. The first plurality of cells 104A (e.g., 4 cells) at the distal end of the engaging member 100 have a cell size / diameter of approximately 0.5 mm. The second plurality of cells 104B (e.g., 4 cells) adjacent to the proximal side of the first plurality of cells 104A have a cell size / diameter of approximately 0.9 mm. The third plurality of cells 104C (e.g., 4 cells) adjacent to the proximal side of the second plurality of cells 104B have a cell size / diameter of approximately 2 mm. 3 A fourth set of cells 104D (e.g., four cells) adjacent to the proximal side of the set of cells 104C has a cell size / diameter of approximately 1.5 mm.

[0085] The size / diameter values ​​described herein are illustrative and should not be interpreted as limiting the range. As stated above and as shown in the figures, the first (most distal) plurality of cells 104A may have a smaller size / diameter than the second plurality of cells 104B, the second plurality of cells 104B may have a smaller size / diameter than the third plurality of cells 104C, and the third plurality of cells 104C may have a larger size / diameter than the fourth plurality of cells 104D. Thus, it can be seen that the size / diameter of cells 104A, 104B, 104C, and 104D may increase first from the distal end of the engaging member 100 and then decrease again at the proximal end.

[0086] To put it another way as a function of length, in the exemplary embodiment described above, the size / diameter of the first (most distal) plurality of cells 104A may be equal to about 17% of the length of the engaging member 100, the size / diameter of the second plurality of cells 104B may be equal to about 30% of the length of the engaging member 100, the size / diameter of the third plurality of cells 104C may be equal to about 66% of the length of the engaging member 100, and the size / diameter of the fourth plurality of cells 104D may be equal to about 50% of the length of the engaging member 100.

[0087] Relatively speaking, in one exemplary embodiment, the first (most distal) plurality of cells 104A may be about 55% of the size / diameter of the second plurality of cells 104B, the second plurality of cells 104B may be about 45% of the size / diameter of the third plurality of cells 104C, and the third plurality of cells 104C may be about 133% of the size / diameter of the fourth plurality of cells 104D.

[0088] As another example, in the patterns shown in Figures 1 to 3, the engaging member 100 can have a length of approximately 6 mm. The first plurality of cells 104A (e.g., 4 cells) at the distal end of the engaging member 100 have a cell size / diameter of approximately 10 mm. The second plurality of cells 104B (e.g., 4 cells) adjacent to the proximal side of the first plurality of cells 104A have a cell size / diameter of approximately 15 mm. The third plurality of cells 104C (e.g., 4 cells) adjacent to the proximal side of the second plurality of cells 104B have a cell size / diameter of approximately 70 mm. The fourth plurality of cells 104D (e.g., 4 cells) adjacent to the proximal side of the third plurality of cells 104C have a cell size / diameter of approximately 20 mm.

[0089] To put it another way as a function of length, in the exemplary embodiment described above, the size / diameter of the first (most distal) plurality of cells 104A may be equal to about 166% of the length of the engaging member 100, the size / diameter of the second plurality of cells 104B may be equal to about 250% of the length of the engaging member 100, the size / diameter of the third plurality of cells 104C may be equal to about 1166% of the length of the engaging member 100, and the size / diameter of the fourth plurality of cells 104D may be equal to about 333% of the length of the engaging member 100.

[0090] Furthermore, the void ratio and performance characteristics of the engaging member 100 can be adjusted by increasing or decreasing the width of each strut 102 portion. The strut may be tapered overall, for example, so that its width decreases towards the center of the engaging member 100. Specifically, the strut 102 may decrease in width distally from a first width at the proximal part of the engaging member 100 forming cell 104D toward the middle part of the engaging member 100 forming cell 104C. Similarly, the strut 102 may decrease in width proximal from a first width at the distal part of the engaging member 100 forming cell 104A toward the middle part of the engaging member 100 forming cell 104C.

[0091] In other words, the proximal strut may be tapered, becoming thicker as the strut 102 approaches the maximum outer diameter of the engaging member 100, and increasing longitudinal stiffness without increasing radial force or follow-through force when tension is applied. The distal strut 102 may return to a closed tube and form a tapered pattern in the opposite direction to the proximal strut. The decrease in stiffness at this position causes the strut 102 to bend inward from the distal closed portion, and the engaging member 100 no longer faces the vessel wall as a whole, so that the distal filter occupies more lumen space. The large central opening allows thrombi to be absorbed by the engaging member 100 and captured by the distal end 113. The flexible proximal strut 102 can be held open in a parachute shape when tension is applied due to the radial and longitudinal stiffness imbalance between the proximal end 111 and the distal end 113.

[0092] As shown in Figures 1 and 2, the engaging member 100 may include one or more radiopaque markers 106. These markers 106 may be composed of a radiopaque material positioned around a portion of one or more struts 102. Various types of radiopaque materials known in the art can be utilized. Non-limitingly, for example, the radiopaque material may be composed of tungsten, platinum-iridium (90% platinum and the remainder iridium), gold, or similar materials.

[0093] The radiopaque material may be a wire, wire coil, wound ribbon, folded sheet, or hypo tube arranged around the strut 102, as shown in Figures 1-2, wound around the strut 102. Figures 9-10 show exemplary embodiments of markers 106A arranged around the strut 102. If necessary, any of these forms of radiopaque markers 106, 106A may be further attached via adhesive, welding, or melting to form beads. In another embodiment, the radiopaque material may consist of a solid member that has been cut open (for example, the material has been cut horizontally and opened like a bivalve shell), and the radiopaque material may be fixed to the strut 102 by attaching the member to the strut 102 and closing the opening with adhesive or welding.

[0094] Non-wire markers, such as sheets or hypotubes, may be designed with the smallest possible amount of material to reduce the amount of bending of the strut 102 within the catheter. Markers made of thin sheet material can be wrapped around the strut such that the marker is one layer outside the hypotube and two or more layers inside the hypotube, thereby increasing the size of the marker without excessively bending the strut away from the catheter liner to the extent that it could cause shortening or plastic deformation of the strut.

[0095] The strut 102 may also include one or more structural features or shapes useful for holding the radiopaque marker 106 in place. An example of such structural feature is the “dogbone” strut shape 104E shown in Figures 4 and 5. This shape 104E forms a region that is wider than adjacent regions at the proximal and distal ends of the strut 102. The expanded shape 104E may further have a greater width at the proximal and distal ends than at the intermediate portion. This may be a shape that is rectangular overall with protrusions 104F, such as “bumps,” that are wider at both ends, or a tapered hourglass shape that is expanded at both ends. The expanded proximal and distal ends allow a radiopaque material, such as a radiopaque wire, to be wrapped around the intermediate portion and prevented from sliding off the shape 104E to the proximal or distal side.

[0096] Figure 6 is an enlarged view of an exemplary embodiment of the strut shape 104E shown in Figures 4 and 5. As shown in Figure 6, the strut shape 104E may consist of a central portion, a distal projection extending distally from the distal side of the central portion, and a proximal projection extending proximally from the proximal side of the central portion. The widths of both the distal and proximal projections may be smaller than the width of the central portion to which they extend. As shown in Figure 6, the corners of the central portion may include projections 104F, such as bumps or ridges, which function as stoppers to prevent the marker 106 from sliding off the strut shape 104E.

[0097] One further advantage of increasing the width of strut shape 104E is that it can be displayed as a relatively large marker area in visualization techniques without requiring a relatively large amount of radiopaque material. In other words, the radiopaque material can be maintained as a thin layer over a larger surface area and is well visible, so no further radiopaque material is required to increase the compressed size or other performance characteristics of the device. For example, strut shape 104E may have a length of about 0.2 mm, a middle width of about 0.005 mm, and an end width of about 0.007 mm.

[0098] Furthermore, as shown in Figures 4 and 5, the strut shapes 104E may be radially offset from each other in a configuration in which the engaging member 100 is radially compressed, so that the markers 106 do not come into contact with each other. For example, two shapes 104E may be longitudinally offset from each other (e.g., the two lower struts in Figure 4), or they may be placed between two radially adjacent struts that do not have such structures 104E (e.g., the three upper struts in Figure 4).

[0099] Figures 7 and 8 show examples of other structural shapes, in which the diameter of region 104G of strut 102 may be smaller than the diameters of the portions adjacent to the proximal and distal sides of strut 102. A radiopaque material, such as a radiopaque wire, may be wrapped around the reduced-diameter region 104G, thereby maintaining a relatively small shape for the radiopaque marker 106.

[0100] In the case of a single engaging member 100 or a distal engaging member 100 connected to multiple proximal engaging members 100, the distal end may include a radiopaque marker 110 as shown in Figure 11. The distal end may, but is not limited to, be made of a radiopaque material such as platinum.

[0101] Figures 12 to 15 show an example of the process for creating an exemplary embodiment of the radiopaque marker 110. First, a metal wire 110A (e.g., stainless steel) having an expansion or ball 110B at one end may be created, as shown in Figure 12. For example, the wire length is about 0.040 inches to about 0.045 inches, the outer diameter is about 0.004 inches, and the outer diameter of the expansion 110B is about 0.0011 inches. The wire 110A may be fed through the distal opening of the engaging member 100 such that the expansion 110B is located proximal inside the engaging member 100, as shown in Figure 13.

[0102] As shown in Figure 14, a hollow cylinder or marker tube 110C is fed onto the wire 110A. The marker tube 110C may, but is not limited to, be made of a radiopaque material such as an alloy of 90% platinum and 10% iridium. In one example, it may have an outer diameter of approximately 0.015 inches, a length of 0.11 inches, a wall thickness of 0.003 inches, and an inner diameter of approximately 0.006 inches. A UV adhesive fillet may be applied to the distal surfaces of the enlarged section 110B and the marker band 110C to form a smooth surface.

[0103] Finally, as shown in Figure 15, the distal end of the wire 110A may be welded to form a second distal enlargement 110D on the distal side of the marker tube 110C, thereby maintaining the marker tube 110C at the distal end of the engaging member 100.

[0104] When the nitinol marker band is welded to the distal end of the stent liver, a slack of 0.005 inches to less than 0.015 inches may occur in the nitinol wire, allowing for smooth marker tracking and connection within the microcatheter. UV adhesive may be further applied to the marker tube 110C and distal expansion 110D as needed, which is useful for creating a smooth surface.

[0105] The obstacle removal device 101 may also consist of a mesh structure 120, which may be configured within the engaging member 100 as shown in Figures 16-17, or adjacent to the engaging member 100 outside of it as shown in Figures 18-19. The mesh structure 120 assists in retaining such embolic fragments by acting as an additional filter to capture them, minimizing the possibility of these fragments being lost during the blood clot retrieval procedure.

[0106] The mesh structure 120 can consist of a single or multiple braided wires, such as a nitinol wire or a stretch-filled tube having a nitinol outer layer and a radiopaque inner core. The mesh structure 120 can be shaped to expand into a desired three-dimensional shape, such as a spherical shape, a tapered ellipse shape, a disc shape, a cylindrical shape, or various other shapes. The mesh structure 120 may be a completely enclosed shape (e.g., spherical), or it may have an opening that forms a concave, cup-shaped, or similar shape. In such a concave shape, it may be desirable to position the concave opening distally to facilitate the capture of the embolism.

[0107] Figure 16 shows an example of an embodiment of an engaging member 100 having an expandable three-dimensional mesh structure 120 inside. The distal and proximal ends of the mesh structure 120 may be internally connected to the distal and proximal ends of the engaging member 100, so that both structures 100 and 120 expand together. Therefore, the mesh structure 120 may assist in the expansion of the engaging member 100 and assist in resistance to crushing.

[0108] Although the mesh structure 120 in the embodiment shown in Figure 16 is depicted as having a longitudinally symmetrical shape (for example, an ellipse with tapered ends), the mesh structure 120 may instead have a longitudinally asymmetrical shape, similar to the engaging member 100 shown in Figure 1.

[0109] Figure 17 shows another exemplary embodiment in which the mesh structure 120 is located only in a portion of the interior of the engaging member 100, specifically in the distal portion or distal half only. However, in some embodiments, the mesh structure 120 may be located only in the proximal portion or proximal half instead.

[0110] In the exemplary embodiment shown in Figure 17, the mesh structure 120 may be enlarged into an overall rounded cylindrical shape, but various different shapes are possible. By positioning the mesh structure 120 distally, the intermediate and proximal parts of the engaging member 100 are freed up, making it easier for the embolus to enter the inside of the engaging member 100, while also enabling more effective capture of the embolus.

[0111] Figures 18-19 show exemplary embodiments in which the mesh structure 120 may be positioned outside the engaging member 100. For example, the mesh structure 120 may be positioned proximal to the engaging member 100 and, if necessary, distal to another engaging member 100. The distal end of the mesh structure 120 may be connected to the proximal end of the engaging member 100, and the two structures may be rotatable relative to each other if necessary.

[0112] Furthermore, the mesh structure 120 may have a uniform void size / porosity along its length, or it may have different void sizes after expansion. For example, as shown in Figure 20, the distal end may have a smaller void size, and as shown in Figure 21, the intermediate section may have a smaller void size than the proximal or distal end.

[0113] As an example, the void size can be varied by using different braiding patterns along the mesh structure 120. For instance, in the embodiments shown in Figures 20 and 21, the braiding patterns can be switched to increase the area with a different PPI ("Picks per inch"). Alternatively, as shown in Figure 22, a portion of the mesh structure 120 can be co-braided to reduce the void ratio in different areas (e.g., the middle of the figure).

[0114] In another example, the mesh structure 120 may be partially shaped to achieve different porosities with the same or different braiding patterns, such that when the mesh structure 120 is expanded, regions are created that expand or contract more in the longitudinal direction.

[0115] In another example, the porosity of a desired region can be reduced by removing or trimming parts of the mesh structure. This is particularly useful when creating a concave or cup-shaped mesh structure 120.

[0116] The engaging member 100 may also include one or more support structures within its structure, which may improve expansion and assist in resistance to collapse, particularly around highly curved portions of blood vessels. As previously mentioned, it may be supported by any of the mesh structures 120.

[0117] As shown in Figures 23-24, the engaging member 100 may include one or more support wires 130. Such one or more support wires 130 can be used instead of or in addition to the mesh structure 120. One or more support wires 130 may be heat-set to an expanded three-dimensional shape equal to or larger than the inner diameter of the engaging member 100, so as to push the engaging member 100 radially outward. The shape of the one or more support wires 130 when expanded may vary in different embodiments and should not be construed as being limited by the exemplary embodiments shown in the figures. In one exemplary embodiment, one or more support wires 130 may be expanded in a helical or coiled shape.

[0118] One or more support wires 130 may form various different shapes. For example, the wires 130 may form an overall helical shape, as shown in Figures 23 and 24. Alternatively, one or more support wires 130 may form one or more discrete circular shapes oriented perpendicular to the axis of the engaging member 100.

[0119] Figures 25A to 25C show an exemplary method for forming the engaging member 100. One or more fasteners 140 may be used as shown. First, an initial shape is formed by weaving wire or using a tubular member such as a hypo tube. Then, one or more fasteners 140 may be placed inside the initial tubular shape to form the asymmetric shape described herein. As an example, a taper may be formed by placing fasteners 140 inside either end of the tubular member before heat-setting it to the final expanded shape as shown in Figures 25A and 25B.

[0120] Figure 25C shows the use of two separate fasteners 140A and 140B, where the first fastener 140A has a smaller diameter or width than the second fastener 140B. The use of multiple fasteners 140A and 140B may be desirable in situations where a single fastener 140 does not fit within the tubular member. In the embodiment shown in Figure 25C, the first fastener 140A may consist of a spacer plunger, and the second fastener 140B may consist of an expansion plate.

[0121] Clauses:

[0122] The embodiments are described in the following numbered clauses.

[0123] The method for removing an obstruction in paragraph 1 may include advancing one or more engaging members from the delivery catheter. Each of the one or more engaging members consists of a plurality of struts forming a plurality of open cells. One or more engaging members have a radially compressed configuration and a radially expanded configuration. The radially expanded configuration forms a longitudinally asymmetric shape having a distal region with a larger diameter than the intermediate and proximal regions. Furthermore, the method includes engaging the obstruction with one or more engaging members.

[0124] The method for manufacturing the obstacle removal system described in paragraph 2 may include forming one or more engaging members. Each of the one or more engaging members includes a plurality of struts and a plurality of open cells. The one or more engaging members have a radially expanded configuration and a radially compressed configuration. The radially expanded configuration forms a longitudinally asymmetric shape having a distal region with a larger diameter than the intermediate and proximal regions. Furthermore, the method includes connecting at least one of the one or more engaging members to an elongated member.

[0125] A method for manufacturing an obstacle removal system described in paragraph 3 may include providing an engaging member comprising a plurality of struts forming a plurality of open cells. At least one of the struts has an expanded region that forms a dogbone shape. Furthermore, the method includes applying a radiopaque material to the central portion of the dogbone shape.

[0126] A method for manufacturing an obstacle removal system, as described in paragraph 4, may include providing an engaging member comprising a plurality of struts forming a plurality of open cells. At least one of the struts has a reduced-width region. The method further includes coating the area around the reduced-width region with a radiopaque material.

[0127] A method for manufacturing an obstacle removal system in paragraph 5 may include providing an engaging member consisting of a plurality of struts forming a plurality of open cells, advancing a wire through the distal end of the engaging member, placing a radiopaque tube on the wire, and forming an enlargement at the distal end of the wire.

[0128] A method for manufacturing an obstacle removal system, as described in paragraph 6, may include providing an engaging member consisting of a plurality of struts forming a plurality of open cells, and connecting a mesh structure to an obstacle removal system or locating a mesh structure near an obstacle removal system.

[0129] The method described in paragraph 7, paragraph 6, wherein the mesh structure is at least partially connected inside the engaging member.

[0130] The method described in paragraph 8, item 6, wherein the mesh structure is positioned outside the engaging member.

[0131] A method for manufacturing an obstacle removal system, as described in paragraph 9, may further include providing an engagement consisting of a plurality of struts forming a plurality of open cells, and connecting a support wire within the obstacle removal system configured to expand into the interior of the engagement member.

[0132] It should be noted that any embodiments, features, or details described herein can be used in combination with each other. In other words, while certain features have been described individually, it is intended that any combination of these features can be combined with each other. Therefore, this specification includes embodiments having any combination of the features described herein.

[0133] While the present invention is described in relation to specific embodiments and uses, those skilled in the art can, in light of this teaching, generate additional embodiments and modifications without departing from or exceeding the spirit of the claimed invention. Therefore, it should be understood that the drawings and descriptions herein are presented as examples to facilitate understanding of the invention and should not be construed as limiting its scope.

Claims

1. An obstacle removal system, A long, slender member, The device comprises an engaging member having a plurality of open cells, the engaging member having a radially compressed configuration and a radially expanded configuration, wherein the radially expanded configuration has a longitudinally asymmetric shape in which the distal region has a larger diameter than the intermediate region and the proximal region. An obstacle removal system characterized in that the engaging member comprises a plurality of struts, at least one of the plurality of struts having a central portion, a proximal projection extending outward from the proximal end of the central portion, and a distal projection extending outward from the distal end of the intermediate region, wherein the central portion is narrower than the proximal projection and the distal projection.

2. The obstacle removal system according to claim 1, characterized in that the plurality of open cells have a lower porosity in the distal region than in the intermediate region.

3. The obstacle removal system according to claim 1, characterized in that the plurality of struts are tapered to a width reduced from the proximal or distal region of the engaging member.

4. The obstacle removal system according to claim 1, characterized in that at least one of the plurality of struts includes a region with reduced width, and further includes a radiopaque material disposed on the region with reduced width.

5. The obstacle removal system according to claim 1, further comprising a radiopaque material disposed on the intermediate region of at least one of the plurality of struts.

6. The obstacle removal system according to claim 1, characterized in that the engaging member has a radiopaque distal tip.

7. The obstacle removal system according to claim 6, characterized in that the radiopaque distal tip portion comprises a wire arranged around the distal end of the engaging member.

8. The obstacle removal system according to claim 1, further comprising a mesh structure connected to the engaging member.

9. The obstacle removal system according to claim 8, characterized in that the mesh structure is disposed within the engaging member.

10. The obstacle removal system according to claim 8, characterized in that the mesh structure is arranged adjacent to the outside of the engaging member.

11. The obstacle removal system according to claim 1, further comprising a support wire disposed within the engaging member.

12. The obstacle removal system according to claim 1, further comprising a second engaging member disposed distal to the engaging member, wherein the width of the second engaging member is smaller than the width of the engaging member.

13. The obstacle removal system according to claim 12, further comprising a third engaging member disposed distal to the second engaging member, wherein the width of the third engaging member is smaller than the width of the second engaging member.

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