Thrombectomy device and method

Abstract

To provide a thrombectomy device that includes several clot arrestors independently mounted on a support wire.SOLUTION: Clot arrestors have expandable frames that are eccentrically supported on a support wire and are arranged to allow a clot to pass into, and be captured by, one of the expandable frames. Furthermore, the clot arrestors can deform independently of one another such that retraction of the thrombectomy device through tortuous vasculature can stretch one clot arrestor without stretching another one of the clot arrestors to allow the clot to be retained by the unstretched clot arrestors.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This application claims priority to U.S. Patent Application No. 17 / 192,786, filed March 4, 2024, and U.S. Patent Application No. 17 / 532,891, filed November 22, 2021, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] The invention disclosed herein relates to a mechanical thrombus removal device (hereinafter, sometimes referred to as a thrombus removal device) used for treating ischemic stroke, and more particularly, to a thrombus removal device used in neurovascular thrombus removal procedures.

[0003] There are various devices to rescue the brain of patients with acute ischemic stroke. Among these, there are thrombectomy devices that are used to remove thrombi from the neurovasculature in the early stages to restore perfusion of the occluded artery. Known thrombectomy devices of this type include coil retriever devices, aspiration devices, and more recently, stent retriever devices.

[0004] Existing stent retriever devices are essentially self-expanding stents that can be deployed within a blood clot to dislodge it or to entangle the clot inside the stent's struts. The stent and clot are then mechanically integrated and withdrawn into a delivery catheter and removed from the patient. Critical factors in the ease of use and performance of a stent retriever device include visibility under fluoroscopy, the ability to capture or engage thrombus, and the ability to retain captured or engaged thrombus as the stent is retracted through tortuous vessels. Deficiencies in these factors can prolong procedure times and reduce clinical success rates. DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0005] Existing stent retriever devices have suboptimal visibility, thrombus engagement, and / or thrombus retention. Most current stent retriever devices are not easily visualized under fluoroscopy during the procedure due to their radiopaque construction. Additionally, most current stent retriever devices employ a one-piece stent body that prevents thrombus capture and engagement. For example, a one-piece stent body may roll over a hard thrombus, thereby bouncing off the thrombus without capturing or engaging the thrombus. Additionally, when the stent body is pulled around a bend in the vessel, the stent body may stretch over its entire length, causing trapped thrombus to become dislodged and lost as the stent body is pulled around the bend. [Means for solving the problem]

[0006] Hereinafter, a thrombus removal device according to the present invention will be described, which is intended to solve the problems of the conventional stent retriever device described above. In one form of the invention, the thrombus removal device includes a plurality of thrombus traps independently supported on a support wire, for example the support wire can have a proximal segment and a distal segment having a smaller diameter or less stiffness than the proximal segment to which the thrombus traps can be attached. More specifically, each of the thrombus traps can include an expandable frame and a stem that can couple the expansion frame to the support wires at a joint that can be a mechanical joint such as a radiopaque marker band that is crimped around the support wires and the stem, thereby allowing the joint to be viewed under fluoroscopy. Furthermore, the thrombus trap is independently supported on the support wire by each of the joints spaced apart longitudinally along the support wire. Therefore, even if a deformation load is applied to one of the expansion frames, the deformation load is not transferred to the other expansion frames. As a result, even if one of the expansion frames stretches and loses contact with the vessel wall when the device is pulled near a bent portion of the vessel, the other expansion frames do not stretch and lose contact with the vessel wall. Thus, the thrombus removal device according to the present invention can more effectively trap and retrieve thrombus from tortuous anatomical structures.

[0007] The expansion frame of the plurality of thrombus traps is eccentrically supported on the support wire. For example, the expansion frame is arranged such that when the thrombus trap is deployed in free space, the trap axis of the expansion frame is not aligned along the wire axis of the support wire, while when the thrombus trap is deployed in a blood vessel, the expansion frame abuts against the vessel wall and is urged (pressed) concentrically against the vessel wall. This aligns the trap axis with the central axis of the blood vessel, and urges (presses) the support wire radially outward toward the vessel wall. The support wire can then extend through the expansion frame in a state offset from the central axis of the blood vessel, for example, helically along the vessel wall, leaving the lumen of the blood vessel and the internal channel of the expansion frame open to receive the thrombus. Thus, the thrombus removal device of the present invention more effectively captures hard thrombus by allowing the hard thrombus to roll into and be captured in the internal channel, rather than rolling between the device and the vessel wall and being lost downstream.

[0008] In addition, the expansion frames of the multiple thrombus traps are supported non-concentrically on the support wire. For example, the expansion frames are arranged such that the trap axes of the expansion frames are not aligned with each other when the thrombus traps are deployed in free space, while when the thrombus traps are deployed in a blood vessel, the expansion frames abut against the blood vessel wall and are concentrically biased (pressed) against each other. The expansion frames tend to return to their undeformed, free state, and can obtain an outward pressing force by their elasticity. This outward pressing force can act on the blood vessel wall in different transverse (radial) directions because the expansion frames are non-concentric in the free state. Such a non-concentric expansion frame therefore allows for increased transverse (radial) force to be distributed around the vessel wall, which can effectively assist in capturing the thrombus as the thrombus removal device of the present invention is withdrawn through the vessel.

[0009] The thrombus trapping effect can be further enhanced by other features of the thrombus removal device of the present invention, such as a filter disposed at the distal end of the device or adjacent openings in an independently supported thrombus trap. The filter can be formed from a self-expanding web or mesh that traps thrombus while allowing blood to pass distally. The openings can be adjusted by varying the spacing of the joints, the shape of the expansion frame, or other variables. Such adjustments can provide ports for the passage of hard or soft thrombus trapped within the internal channel of the thrombus removal device. Methods of making a thrombus removal device according to the present invention and methods of using the thrombus removal device to remove a thrombus from a blood vessel are described further below.

[0010] The thrombus removal device can include a thrombus trap having a segmented structure. For example, the distal-most thrombus trap can have a segmented body including a proximal frame segment and a distal frame segment. The frame segments can be connected with a hinge-like connector between the frames. When an axial load is applied to the thrombus removal device (e.g., when the device is retracted within a vessel), the frame segments can tilt about the hinge. More specifically, during thrombus retrieval, the frame segments can tilt toward each other while being biased concentrically. This tilting action can cause the frame segments to push outwardly against soft thrombus that is covering and adhering to the vessel wall, and can separate the frame segments to allow harder thrombus to pass through the gap between the frame segments and into the lumens of the frame segments.

[0011] The summary of the present invention above is not an exhaustive listing of all aspects of the present invention. The present invention includes all apparatus and methods that can be implemented from all suitable combinations of the various aspects described in the summary above, the aspects disclosed in the detailed description below (details for implementing the invention), and the aspects specifically pointed out in the claims filed with this application. Such combinations have unique advantages not specifically described in the summary above.

[0012] The novel features of the invention are set forth with particularity in the claims appended hereto. For a better understanding of the features and advantages of the present invention, reference is made to the following detailed description that sets forth illustrative embodiments in which the principles of the invention are applied, and the accompanying drawings in which: [Brief description of the drawings]

[0013] [Figure 1] 1 is a plan view of a thrombus removal device according to an embodiment of the present invention.

[0014] [Diagram 2] 1 is a plan view of a distal portion of a thrombus removal device having multiple thrombus traps, according to an embodiment of the present invention.

[0015] [Diagram 3] 1 is a perspective view of a distal portion of a thrombus removal device having multiple thrombus traps according to an embodiment of the present invention.

[0016] [Figure 4] FIG. 13 is an end view showing multiple thrombus traps deployed in free space, according to an embodiment of the present invention.

[0017] [Diagram 5] 1 is an end view showing multiple thrombus traps deployed within a blood vessel, according to an embodiment of the present invention.

[0018] [Figure 6] FIG. 13 is a side view showing multiple thrombus traps deployed in free space, according to an embodiment of the present invention.

[0019] [Figure 7] FIG. 1 is a side view showing multiple thrombus traps deployed in a straight vessel, according to an embodiment of the present invention.

[0020] [Figure 8] FIG. 1 is a perspective view of a thrombus trap according to an embodiment of the present invention.

[0021] [Figure 9] FIG. 2 is a side view illustrating a thrombus trap according to an embodiment of the present invention.

[0022] [Figure 10] FIG. 1 is a perspective view of a thrombus trap according to an embodiment of the present invention.

[0023] [Figure 11] FIG. 1 is a perspective view showing a filter attached to a thrombus trap according to an embodiment of the present invention.

[0024] [Figure 12] 1 is a schematic diagram showing a thrombus removal device deployed in a curved vessel, according to an embodiment of the present invention.

[0025] [Figure 13] 1A-1C are schematic diagrams illustrating a thrombus removal device being pulled into a bend in a tortuous vessel, according to an embodiment of the present invention.

[0026] [Figure 14] 4 is a flow chart illustrating a method for manufacturing a thrombus removal device, in accordance with an embodiment of the present invention.

[0027] [Figure 15] 4 is a flow chart illustrating a method of removing a thrombus from a blood vessel using a thrombus removal device, in accordance with an embodiment of the present invention.

[0028] [Figure 16] 13 is a plan view of a distal portion of a thrombus removal device having multiple thrombus traps according to another embodiment of the present invention. FIG.

[0029] [Figure 17] FIG. 13 is a perspective view of a thrombus removal device including a support wire with one or more bends according to another embodiment of the present invention.

[0030] [Figure 18] 13 is a plan view showing a distal portion of a thrombus removal device having multiple thrombus traps deployed in free space according to another embodiment of the present invention. FIG.

[0031] [Figure 19] 13 is a plan view showing a distal portion of a thrombus removal device having multiple thrombus traps deployed within a blood vessel according to another embodiment of the present invention. FIG.

[0032] [Figure 20] FIG. 13 is a perspective view showing a distal-most thrombus trap of a thrombus removal device according to another embodiment of the present invention.

[0033] [Figure 21] 13 is a side view showing multiple thrombus traps deployed within a blood vessel according to another embodiment of the present invention. FIG.

[0034] [Figure 22] 13 is a side view showing multiple thrombus traps deployed within a blood vessel according to another embodiment of the present invention. FIG.

[0035] [Diagram 23] FIG. 2 is a perspective view showing a frame marker according to an embodiment of the present invention.

[0036] [Figure 24] FIG. 2 is a plan view showing a radiopaque coil attached to a support wire of a thrombus removal device, according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A thrombus removal device according to an embodiment of the present invention, namely a thrombus removal device having a thrombus trap attached independently and eccentrically to a support wire, is described below. The thrombus removal device according to the embodiment is suitable for use in the treatment of acute ischemic stroke, but may also be used in other applications, such as, but not limited to, the removal of thrombus from other blood vessels.

[0038] Although various embodiments are described with reference to the drawings, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details, such as specific configurations, dimensions, processes, etc., are shown in order to facilitate understanding of the embodiments. On the other hand, well-known processes and manufacturing techniques are not described in particular detail in order not to obscure the description. As used herein, references to "one embodiment," "an embodiment," or the like mean that a particular feature, structure, configuration, or characteristic being described is included in at least one embodiment. Thus, appearances of the phrases "one embodiment," "an embodiment," or the like in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.

[0039] The use of relative terms herein indicates relative positions or directions. For example, "distal" may indicate a first direction along the longitudinal axis of the support wire or thrombus trap. Similarly, "proximal" may indicate a second direction opposite the first direction. However, such terms are provided to establish a relative frame of reference and are not intended to limit the use or procedure of the thrombus removal device to the specific configurations described in the various embodiments below.

[0040] In one aspect of the embodiment, the thrombus removal device includes a plurality of thrombus traps attached to a support wire, each thrombus trap being independently attached, more particularly, each thrombus trap including an expansion frame that is attached to the support wire independently of the expansion frames of the other thrombus traps. Unlike competing devices that stretch significantly when pulled around bends in tortuous vessels, the segmented configuration of the thrombus removal device allows the thrombus traps to operate independently of each other, so stretching one thrombus trap does not stretch the other thrombus traps significantly. As a result, when the thrombus removal device is retracted around the bent portion, even if the thrombus trap at the bent portion stretches and loses contact with the vessel wall, the thrombus hemostatic material distal and proximal to the bent portion does not stretch and maintains contact with the vessel wall. Therefore, even if the thrombus trap at the bent portion loses engagement with the thrombus, the thrombus will move to, be captured, and held by the other thrombus traps that are in contact with the vessel wall.

[0041] In one aspect of the embodiment, the thrombus trap of the thrombus removal device is eccentrically supported on the support wire. When the thrombus trap is deployed into a vessel and into a concentric relationship therewith, the support wire is pushed off-center and is thereby offset from the central axis of the vessel and is able to extend through the expansion frame of the thrombus trap. This eccentric positioning of the expansion frame and the off-center positioning of the support wire facilitates passage of the thrombus through the expansion frame and allows it to be captured by the expansion frame. The unitary stent bodies of existing stent retriever devices may not allow thrombus capture (instead allowing the thrombus to roll between the stent body and the vessel wall while the device is retracted), whereas the segmented thrombus traps of embodiment thrombus removal devices allow thrombus to enter gaps between the thrombus traps and thereby be captured by the thrombus traps.

[0042] In one aspect of the embodiment, the thrombus trap of the thrombus removal device is attached to the support wire by a joint that is highly visible under fluoroscopy. For example, each joint connecting a thrombus trap to a support wire can include a radiopaque marker. Such a radiopaque marker indicates a particular location along the support wire relative to the thrombus trap. Thus, the radiopaque marker improves visibility of the thrombus removal device and provides a clue to the operator of the thrombus removal device to understand where the thrombus is located relative to the thrombus trap.

[0043] FIG. 1 shows a plan view of a thrombus removal device according to an embodiment. The thrombus removal device 100 is an intravascular tool that can be used to treat acute ischemic stroke. The thrombus removal device 100 includes a proximal working region 102 that an operator uses to advance, retract, and rotate a distal working region 104 of the device. More specifically, the thrombus removal device 100 includes a support wire 106 that an operator uses to push to advance the distal working region 104, pull to retract the distal working region 104, or twist to rotate the distal working region 104. The thrombus removal device 100 also includes a plurality of thrombus traps 108 that can be advanced through the microcatheter and deployed from the microcatheter into the target anatomical structure. Once deployed into the target anatomical structure, the thrombus traps 108 can trap, entrap, engage, or mechanically integrate with the thrombus. The thrombus thus trapped is retrieved from the patient by pulling the support wire 106 to retract the thrombus traps 108 and thrombus from the vasculature.

[0044] In one embodiment, the supporting wire 106 includes a proximal wire end 110 and a distal wire end 112 and extends longitudinally along a wire axis from the proximal wire end 110 to the distal wire end 112. The supporting wire 106 may be a flexible, elongated wire formed from a resilient material, such as stainless steel or a superelastic nickel-titanium alloy. This allows the wire axis of the supporting wire 106 to have one or more straight or curved segments between the proximal wire end 110 and the distal wire end 112. The length of the support wire 106 may be less than the overall length of the thrombus removal device 100. For example, the distal wire end 112 may be located distal to at least one of the thrombus traps 108 and proximal to the distal end of at least one of the thrombus traps 108. Thus, the distance from the proximal wire end 110 (proximal device end 114) to the distal wire end 112 may be less than the distance from the proximal wire end 110 to the distal device end 116.

[0045] 2 shows a plan view of a distal portion of a thrombus removal device having multiple thrombus traps, according to an embodiment, that are independently attached to a support wire 106. More specifically, each thrombus trap 108 includes a respective expansion frame, and each expansion frame of the thrombus trap 108 is connected to the support wire 106 at a respective location. For example, the first thrombus trap 202 has a first expansion frame 204 and a first stem 206 that connects the first expansion frame 204 to the support wire 106 at a first joint 208. The first joint 208 is at a first location 209 along the support wire 106. The second thrombus trap 210 has a second expansion frame 212 and a second stem 214 that connects the second expansion frame 212 to the support wire 106 at a second joint 216. The second joint 216 is at a second location 217 along the support wire 106. The thrombus removal device 100 can have more than two thrombus traps 108. For example, the third thrombus trap 218 has a third expansion frame 220 and a third stem 222 that connects the third expansion frame 220 to the support wire 106 at a third joint 224. The third joint 224 is at a third location 225 along the support wire 106. The attachment location of each thrombus trap 108 can be spaced longitudinally along the support wire 106. For example, the first location 209, the second location 217, and the third location 225 are at different longitudinal locations on the support wire 106. This allows the thrombus traps 108 to be arranged in series with the expansion frames longitudinally, with each expansion frame being independently supported on the support wire 106 relative to the other expansion frames.

[0046] Sequential thrombus traps 108 can have the same or different structures. For example, in the embodiment shown in FIG. 2, the most proximal thrombus trap, i.e., first thrombus trap 202, and the middle thrombus trap, i.e., second thrombus trap 210, are identical in that the stems and joints of their expansion frames have the same shape. In contrast, the most distal thrombus trap 108, i.e., third thrombus trap 218, can have a different shape than the first thrombus trap 202 and the second thrombus trap 210. Some of these geometric differences are described below, one difference is the presence of one or more struts 230 extending distally from the expansion frame to support a filter 232 at the distal device end 116. In this manner, the independently supported thrombus traps 108 can be sized and shaped to provide respective thrombus engagement, thrombus capture, flexibility, or any other performance attribute.

[0047] FIG. 3 shows a perspective view of a distal portion of a thrombus removal device having multiple thrombus traps, according to an embodiment. The support wire 106, which supports the thrombus traps 108, has a proximal segment 302 and a distal segment 304. The proximal segment 302 extends proximally of the thrombus traps 108 and onto the proximal working region 102, and the distal segment 304 extends through one or more of the thrombus traps 108 and into the distal working region 104.

[0048] Each segment of the support wire 106 can be adapted for its purpose. For example, the proximal segment 302 can function primarily to transfer axial and rotational loads from the operator to the distal working region 104. Thus, the proximal segments 302 of the support wire 106 can have a proximal diameter 306 appropriate for their function. By way of example, the proximal diameter 306 can be set in the range of 0.010 inches to 0.020 inches (e.g., 0.018 inches). In contrast, the distal segment 304 may not function primarily to transmit actuation forces, but rather may function primarily as a support for the thrombus trap 108. To that end, the distal segment 304 may have a distal diameter 308 that is smaller than the proximal diameter 306. For example, the distal diameter 308 may be between 0.004 inches and 0.010 inches (e.g., 0.0045 inches). Thus, the proximal segment 302 of the support wire 106 may have a larger diameter than the distal segment 304 of the support wire 106. The smaller diameter of the distal segment 304 is also useful for other purposes. First, the smaller diameter can provide flexibility to the distal segment 304 of the support wire 106, allowing it to undulate and spiral along the inner dimensions of the target anatomy and the thrombus trap 108, as described below. Second, because the distal segment 304 extends through the thrombus trap 108, the smaller diameter allows for a smaller packing ratio when advancing the thrombus removal device 100 through a microcatheter. This smaller packing ratio allows the device to be more easily delivered through a microcatheter to the target anatomy.

[0049] The support wire 106 configurations described above can be achieved with a single wire. For example, a single wire can be ground or otherwise tapered at discrete locations between the proximal wire end 110 and the distal wire end 112 to form the proximal and distal segments 302 and 304. As an example, a single wire can be 0.018 inches at the proximal wire end 110 and tapered distally along its length to have diameters of 0.010 inches, 0.006 inches, and 0.0045 inches at different locations along the wire length. The taper can be uniform or can be introduced at discrete locations to form multiple wire segments having respective diameters.

[0050] In one embodiment, the supporting wire 106 is formed by joining multiple wire segments. For example, the proximal segment 302 can be a first wire having a distal end at the first location 209. Similarly, the supporting wire 106 can include a second wire having a proximal end at the first location 209. The first wire can have a larger diameter than the second wire, as previously described. Such wire segments may be joined by a joint. For example, the first joint 208 that attaches the first thrombus trap 202 to the support wire 106 may join the ends of multiple wire segments to form a unitary support wire 106.

[0051] Each joint of the thrombus removal device 100 can be formed using mechanical, thermal, or adhesive means. For example, the first joint 208 can include a marker band that is mechanically crimped around the support wire 106 and the first stem 206 of the first thrombus trap 202 to attach the thrombus trap to the support wire 106. The marker band can be a tubular sleeve formed from platinum iridium, stainless steel, gold, tungsten, or other radiopaque material. Such a marker band can provide a radiopaque marker 310. The first stem 206 can include a tail portion that is disposed inside the marker band adjacent to the support wire 106. When the marker band is crimped, the support wire 106 and stem can be crimped to secure the first thrombus trap 202 to the support wire 106. In one embodiment, the marker band, the thrombus trap, and the support wire 106 may be secured together with an adhesive to form the first joint 208 .

[0052] The joints described above may be formed in other ways, for example any joint between the thrombus trap and the support wire 106 may be formed using a laser welded, soldered, or brazed joint. Joints by mechanical, thermal, or adhesive means can secure the radiopaque markers 310 to the support wire 106 while providing adequate radiopacity. For example, a tungsten rod may be adhered to the support wire 106 at the first location 209. Such a thrombus removal device 100 includes radiopaque markers at the joints along the support wire 106.

[0053] The radiopaque markers facilitate visualization of the thrombus removal device under fluoroscopy. The locations of the joints and radiopaque markers 310 can be used as cues to the operator to understand the relative placement between the thrombus trap and the thrombus within the target anatomy. For example, if the radiopaque marker 310 of the first joint 208 is proximal to the first expansion frame 204, the operator can retract the thrombus removal device 100 to retract the first joint 208 past the thrombus so that the thrombus enters the interior of the first expansion frame 204. Similarly, another radiopaque marker 310 can be placed at the second joint 216 at a second location 217 along the support wire 106. This allows the operator to retract the thrombus removal device 100 and retract the second joint 216 past the thrombus so that it is inside the second expansion frame 212. Similarly, another radiopaque marker 310 can be placed at the third joint 224 at a third location 225 along the support wire 106. This allows the operator to retract the thrombus removal device 100 and retract the third joint 224 past the thrombus so that it becomes interior to the third expansion frame 220.

[0054] Locating the radiopaque markers 310 proximally rather than internally of each expansion frame provides several advantages. First, as previously mentioned, these positions provide clear feedback to the operator as to the relative positions between the markers, the longitudinally aligned thrombus, and the interior of each expansion frame. Second, by placing the marker bands proximally rather than longitudinally at the same location as the expansion frame, the expansion frame can collapse to its unexpanded state distal to and without surrounding the radiopaque markers 310. More specifically, the radiopaque markers 310 do not contribute to the collapsed diameter of the expansion frame because the joints are proximal to the expansion frame, i.e., the joints do not increase the collapsed diameter. As a result, this relative location of the markers to the expansion frame favors the puncture ratio (smaller unexpanded profile) of the thrombectomy device 100 and contributes to improved delivery of the thrombectomy device through a microcatheter.

[0055] FIG. 4 illustrates an end view of multiple thrombus traps deployed in free space, according to an embodiment. Each thrombus trap 108 has an extension frame that is independently attached to and eccentrically supported on a support wire 106. The support wire 106 includes a wire axis 402 that extends longitudinally through the wire body. As previously mentioned, because the support wires 106 are flexible, the wire axis 402 can have straight and curved segments. However, for modeling purposes, the wire axis 402 is sometimes shown as straight (FIG. 3) and is represented as a single point in the end view of FIG. 4.

[0056] Each thrombus trap 108 has a trap axis 404 that is radially offset from the wire axis 402. As described below, the thrombus traps 108 can be formed by laser cutting a three-dimensional expandable structure from a cylindrical tube, such that the expanding frame of the thrombus traps 108 can have a circular cross-sectional shape (profile), as shown in FIG. The centers of these cross-sectional shapes define respective trap axes 404 extending longitudinally through the thrombus trap 108. Because the trap axes 404 are radially spaced from the wire axis 402, the thrombus trap 108 is eccentrically supported on the support wire 106. More specifically, the stem of the thrombus trap 108 is attached to the support wire 106 at the wire axis 402, while the expansion frame of the thrombus trap 108 is eccentrically supported relative to the support wire 106.

[0057] In one embodiment, the eccentrically supported expansion frame is oriented radially about the wire axis 402. Each thrombus trap 108 can have a respective radial plane that includes the wire axis 402 and a respective trap axis 404. For example, a first radial plane 406 extends radially from the wire axis 402 through a first trap axis 408 of the first thrombus trap 202. Similarly, a second radial plane 410 extends radially from the wire axis 402 through a second trap axis 412 of the second thrombus trap 210, and a third radial plane 414 extends radially from the wire axis 402 through a third trap axis 416 of the third thrombus trap 218. The radial planes may be angularly offset from one another around the support wire 106. For example, the radial planes may be disposed radially in different directions from the wire axis 402 such that the expansion frames are non-concentrically supported on the support wire 106 relative to one another. The non-concentric distribution of the expansion frames is evident from the capture axes becoming non-coaxial when viewed distally.

[0058] The radial planes of the thrombus traps 108 may be uniformly or non-uniformly distributed around the support wire 106. In the embodiment shown in FIG. 4, the radial planes are non-uniformly distributed around the support wire 106. More specifically, the angle between the first radial plane 406 and the second radial plane 410 in the counterclockwise direction is about 60°, the angle between the second radial plane 410 and the third radial plane 414 in the counterclockwise direction is about 60°, and the angle between the third radial plane 414 and the first radial plane 406 in the counterclockwise direction is about 240°. That is, the angles between circumferentially adjacent thrombus traps 108 are not equal, and the thrombus traps 108 are not uniformly oriented with respect to the support wire 106. In contrast, the radial planes may be uniformly distributed when the angles between all circumferentially adjacent thrombus traps 108 are equal. In the general case, the angle between the radial planes is 360° divided by the number of thrombus traps 108. For example, if there are three thrombus traps 108, and the angle between the first plane, the second plane, and the third plane is 120°, the expansion frame is uniformly distributed with respect to the support wire 106. Thus, it is understood that the non-uniform distribution is exemplary and that the radial planes may be uniformly distributed around the support wire 106 when the angles between the radial planes are equal.

[0059] FIG. 5 illustrates an end view of multiple thrombus traps deployed within a blood vessel, according to an embodiment. FIG. 4 illustrates an eccentrically supported expansion frame, as previously described, in which the capture axes of the thrombus capture devices 108 do not align when the distal working region 104 is naturally expanded in free space, e.g., in a space where no external force is applied to the expansion frame. In contrast, FIG. 5 illustrates the effect of an independently eccentrically supported thrombus trap 108 when deployed in a blood vessel 502.

[0060] When the non-concentrically supported expansion frame is restrained by the vessel wall 504 of the vessel 502, the vessel wall 504 presses the expansion frame radially inward, moving the thrombus trap 108 in a concentrically supported direction. More specifically, given that the radial strength of the vessel wall 504 is greater than the stiffness of the distal segment 304 of the support wire 106, the support wire 106 flexes the eccentrically supported expansion frame toward a concentric arrangement. However, in the illustrated example, the expansion frame is not perfectly concentric, which may be the case in practice because the elasticity of the support wires 106 acts individually on each thrombus trap 108 as a result of their independently supported construction, urging the thrombus trap 108 in different directions relative to the wire axis 402. Thus, as shown in the enhanced illustration of FIG. 5, when multiple thrombus traps 108 are deployed within a blood vessel 502, the expansion frame is forced against the vessel wall 504 in different diagonal directions, as indicated by the force vectors 506.

[0061] It should be noted that the cross sections of the first thrombus trap 202, the second thrombus trap 210, and the third thrombus trap 218 shown in Figure 5 are actually overlapped at different longitudinal positions, and therefore the cross sections of the support wire 106 shown in Figure 5 are at different longitudinal positions. This realization indicates that deployment of the thrombus trap 108 in an occluded space, such as a blood vessel 502, forces the support wires 106 into a non-linear shape that is not centered (central axis) in the space. More specifically, when the thrombus trap 108 is deployed in the blood vessel 502 with the expansion frame against the vessel wall 504, the support wires 106 will extend through one or more expansion frames at a location offset from the central axis 510 of the blood vessel 502. The advantages of such an independently eccentrically supported thrombus trap 108 configuration are described further below.

[0062] 6 illustrates a side view of multiple thrombus traps deployed in free space, according to an embodiment. As previously discussed, each thrombus trap 108 includes a respective stem 602 that couples a respective extension frame 604 to the support wire 106 by a respective joint 606. Although the stems 602, extension frames 604, and joints 606 may be individually labeled, e.g., first, second, and third, as previously discussed, in FIGS. 6-7, these characteristic references are uniformly labeled and are provided as a generalization of these features. In a natural, unloaded state, the support wires 106 may be arranged linearly, extending through one or more of the expansion frames 604. For example, the support wires 106 pass completely through the proximal and middle expansion frames 604 in FIG. 6 and terminate at the proximal end of the distal expansion frame 604. The joints 606 are spaced longitudinally along the support wires 106 such that the stems 602 are separated from one another such that the expansion frame 604 is independently supported by the support wires 106. Additionally, the expansion frame 604 is eccentrically supported on the support wires 106. This is evident from the fact that the capture axis 404 is radially offset (vertically offset in side view) from the wire axis 402.

[0063] FIG. 7 shows a side view of multiple thrombus traps deployed in a linear (straight) blood vessel, according to an embodiment. When the distal working region 104 is deployed within a blood vessel 502, the vessel wall 504 applies a deformation load 702 to the thrombus trap 108. In this case, the deformation load 702 is a radial load, causing the trap axis to move into radial alignment. The deformation load 702 may also be an axial load (FIG. 13) that causes stretching of one or more expansion frames 604. In any event, as a result of the thrombus traps 108 being independently supported at longitudinally spaced joints 606, the deformation load 702 applied to one expansion frame 604 is not transferred to the other expansion frames 604. Rather, the expansion frames 604 flex independently of one another. 7, in this regard, the proximal and distal extension frames 604 are shown moving downward while the middle extension frame 604 moves upward. Such independent movement of the extension frames 604 causes the capture axis 404 to become linearly aligned.

[0064] As the expansion frame 604 aligns within the vessel, the support wire 106 bends into a non-linear shape. More specifically, the proximal segment 302 of the support wire 106 may remain straight, e.g., straight, but considering that the trap axis 404 is eccentrically positioned relative to the wire axis 402, the distal segment 304 of the support wire 106 supporting the expansion frame 604 may become non-linear, e.g., curved, as the trap axis 404 becomes more central, e.g., aligned with the central axis 510 of the vessel 502. More specifically, the wire axis 402 becomes biased away from the center (e.g., radially outward toward the vessel wall 504), which may cause the support wire 106 to assume a curved shape that differs from the straight shape of the proximal segment 302.

[0065] In one embodiment, the support wires 106 extend through each thrombus trap 108 along the inner wall of the respective expansion frame 604. For example, as shown in FIG. 5 , the support wires 106 in each expansion frame 604 are positioned along the inner wall of the expansion frame 604 and are circumferentially offset from the location where the primary force vector 506 acts on the vessel wall 504. The support wire 106 may undulate along the vessel wall 504. This is illustrated in the side view of FIG. 7 by the curved path of the support wire 106 along its length. Such an undulating path has peaks and valleys where the support wire 106 is forced against the vessel wall 504 by the deformation load 702. These peaks and valleys may correspond to the interior channels of the expansion frame 604, e.g., the support wire 106 may have peaks or valleys on the inner wall of the expansion frame 604. In one embodiment, the support wire 106 is forced against the inner wall of the expansion frame 604 as it is urged away from the central axis 510 of the vessel 502.

[0066] Tertially, the undulating path of the support wire 106 may become a helical path. More specifically, when the thrombus traps 108 are arranged non-concentrically around the wire axis 402, the deformation load 702 moves the expansion frames 604 independently in different directions, aligning them with each other and with the vessel lumen. The connections to the support wires 106, e.g., each joint 606, may then be biased in different directions. This may allow the support wires 106 at one joint 606 to be biased to the vessel 502 at a first radial position, e.g., 0 degrees, another joint 606 to be biased to the vessel 502 at a second radial position, e.g., 120 degrees, and yet another joint 606 to be biased to the vessel 502 at a third radial position, e.g., 240 degrees. As the supporting wire 106 extends longitudinally through each of these radially located joints 606, it may assume a helical configuration. Specifically, the supporting wire 106 may spiral along the vessel wall 504 as the expansion frame 604 and respective joints 606 contact the vessel wall 504. In this manner, the supporting wire 106 may undulate distally while contacting the vessel wall 504 at one or more peaks or valleys, and may also spiral distally while contacting the vessel wall 504 continuously over the length of the distal segment 304 of the supporting wire 106.

[0067] The serpentine or helical support wire 106 provides several performance advantages. First, the offset of the support wires 106 from the vessel wall 504 causes each expansion frame 604 to press against the same vessel with a different directional force vector 506. The support wires 106 generate a reaction load to the deformation load 702 applied to the expansion frame 604 by the vessel wall 504, and this reaction load acts on the vessel wall 504 as a force vector 506. When the thrombus trap 108 is deployed within the blood vessel 502, the support wires 106 are biased in different directions away from the central axis 510 of the blood vessel 502. Accordingly, the reaction load is directed in a direction opposite to these biasing forces. Thus, the expansion frame 604 is subjected to a force vector 506 in which the support wires 106 press against the vessel wall 504, thereby providing a higher radial force to the vessel wall 504 when the expansion frame 604 is deployed within the blood vessel.

[0068] A second advantage of the undulating or helical support wire 106 is the clearance available for thrombus capture. When the thrombus trap 108 is deployed within the blood vessel 502, the support wires 106 are offset to the periphery of the expansion frame 604 and the blood vessel 502, thereby keeping the central lumen, e.g., the inner channel of the expansion frame 604, completely open to the passage of thrombus. 7, when the expansion frames 604 are expanded and abut the vessel wall 504, the support wires 106 run along the vessel wall 504 at different circumferential positions of each expansion frame 604. Gaps 704 exist between adjacent expansion frames 604, which can provide openings through which thrombus can enter the central lumen of the thrombus removal device 100. This central lumen can then provide a volume of space formed radially inward from the vessel wall 504 and the inner wall of the expansion frames 604. A centrally located support wire 106 (e.g., a support wire 106 aligned with the central axis 510 of the blood vessel 502) may prevent thrombus from entering the central lumen and may deflect thrombus radially outward, which may then roll between the outer surface of the expansion frame 604 and the vessel wall 504 and not be captured. In contrast, the circumferentially offset support wires 106 maximize the central lumen volume for receiving thrombus without blocking the central lumen, and the thrombus can migrate completely into the central lumen to be captured by the expansion frame 604 in the process of being pulled through the vessel 502, rather than diverting outward.

[0069] In addition to using circumferentially offset support wires 106 to open the central lumen of the device to receive thrombus, the gap 704 between the expansion frames 604 can also be adjusted to improve thrombus capture. More specifically, the opening between the distal frame end 706 of one expansion frame 604 and the proximal frame end 708 of the adjacent expansion frame 604 functions as a channel or port for introducing thrombus into the central lumen of the device. The gap 704 can be sized to ensure that a thrombus, e.g., a hard thrombus rolling between the expansion frame 604 and the vessel wall 504, will fit into the gap 704 when aligned longitudinally with respect to the gap 704. The distance between the distal frame end 706 of one expansion frame 604 and the proximal frame end 708 of the adjacent expansion frame 604 can be in the range of 10-20 mm, particularly 15 mm, to accommodate most hard thrombus, although it can of course be set at a different longitudinal distance depending on the range of thrombus sizes to be captured.

[0070] In one embodiment, the gap 704 between a pair of expansion frames 604 may be different in size or shape than the gap 704 between another pair of expansion frames 604. For example, the length of the gap 704 between the proximal-most and middle expansion frames 604 in FIG. 7 may be different from the length of the gap 704 between the middle and distal-most expansion frames 604 in FIG. 7 (e.g., may be shorter than the length of the gap 704 in FIG. 7). Similarly, the structure of the expansion frames 604 can have different shapes, such that the gap 704 between the proximal-most expansion frame 604 and the intermediate expansion frame 604 in FIG. 7 is a different shape than the gap 704 between the intermediate expansion frame 604 and the distal-most expansion frame 604 in FIG. 7. Varying the length and / or shape of such gaps may provide adaptable openings to accommodate more or less of different clot types, for example, a shorter and wider proximal opening may be suitable for capturing harder clots, while a longer and narrower distal opening may be suitable for capturing softer clots.

[0071] FIG. 8 shows a perspective view of a thrombus trap according to one embodiment. As previously discussed, each thrombus trap 108 has components as an extension frame 604 and a stem 602. The extension frame 604 includes a distal frame end 706 and a proximal frame end 708. These frame ends define openings to the interior channel 812 of the extension frame 604, e.g., a proximal opening to the cylindrical interior of the extension frame 604 and a distal opening to the cylindrical interior. The expansion frame 604 can include at least one frame cell ring 802. The frame cell ring 802 can be configured to expand and contract. Geometrically, the expansion frame 604 can resemble a stent. For example, the frame cell ring 802 can include two or more cells circumferentially connected to one another and formed into a cylindrical expandable structure having an "open" or "closed" cell pattern. Such a cellular pattern includes one or more slots, struts, or links 820 to form an expandable structure with proximal and / or distal openings for trapping a thrombus. Similar to a stent, the thrombus trap 108 can be formed by laser cutting the cellular pattern from a metal tube. As an example, the expansion frame 604 can be a self-expanding structure formed from a shape memory alloy, such as a nickel-titanium tube. However, unlike a stent, the radial force of the expansion frame 604 is required to act to maintain a secondary structural shape that is responsive to trapping a thrombus, rather than acting as a support to open an arteriosclerotic lesion.

[0072] Also, unlike a stent support, the thrombus trap 108 can include a stem 602 extending proximally from the expansion frame 604. More specifically, the stem 602 can extend proximally from the proximal ring end 803 (proximal frame end 708) of the frame cell ring 802 to a proximal stem end 804. The proximal stem end 804 can define the proximal location of the thrombus trap 108, just as the distal frame end 706 can define the distal location or end of the thrombus trap 108. Neither the distal end nor the proximal end of the thrombus trap 108 is directly connected to an adjacent thrombus trap. That is, the thrombus trap 108 is a free-hanging entity suspended from the support wire 106.

[0073] In one embodiment, the stem 602 includes one or more branches extending from the proximal stem end 804 to the proximal frame end 708. The stem 602 may be a single straight wire segment extending proximally from the extension frame 604 to the joint 606 of the support wire 106, as modeled in Figures 6 and 7. However, in one embodiment, the stem 602 includes multiple branches extending between the joint 606 of the proximal stem end 804 and the proximal ring end 803 of the frame cell ring 802. These branches can act like tails connecting the frame cell ring 802 to the support wire 106 while pulling the extension frame 604. The shape of the branches can transfer forces (e.g., pulling forces) to the extension frame 604 during operation and contribute to thrombus capture.

[0074] The aforementioned branching branches can have a structure that branches one or more times between the proximal stem end 804 and the proximal frame end 708 to connect to each of the proximal ring ends 803 for transmitting the pulling force. More specifically, the stem 602 can extend proximally from each proximal apex of the expandable ring structure. This allows the pulling force transmitted from the support wire 106 to the expansion frame 604 via each stem branching branch to be uniformly distributed around the proximal frame end 708. Such uniform distribution of the pulling force can reduce tilting of the expansion frame 604 during device retrieval, thus reducing vascular damage and / or thrombus loss.

[0075] Some of the branched branches of the stem 602 may define an access 810 to an internal channel 812 of the expansion frame 604. For example, a pair of branched branches may branch near the proximal stem end 804 and extend distally toward the proximal ring end 803. These pair of branched branches continue along the proximal end of the frame cell ring 802 at the proximal ring end 803 and converge at a link 820 between two adjacent frame cells. Such diverging and converging branches can form an "eye" shaped passage 810 that provides a proximal opening to an interior channel 812. More specifically, a closed negative space between two arcuate branches can provide the passage 810. Similarly, another port can be defined between the branches of the stem 602 on the opposite side of the trap structure. This other port can be separated from the illustrated port 810 by a branch, but can open into the same interior channel 812. The port of the thrombus trap 108 thus provides a port through which thrombus can enter and be trapped in the expansion frame 604.

[0076] 9 shows a side view of the thrombus trap according to the embodiment. In this side view, the division (boundary) between the expansion frame 604 located distal to the proximal ring end 803 and the stem 602 located proximal to the proximal ring end 803 can be confirmed. The interior channel 812 provides a volume within the expansion frame 604. The stem 602 extends proximally from the expansion frame 604 to a joint 606 at the proximal stem end 804, which connects the thrombus trap 108 to the support wire 106. The branches of the stem 602 can branch off to connect to different proximal ring ends 803. Additionally, the branches of the stem 602 form an aperture 810 having an aperture plane 902, shown in side view in Figure 9. The aperture plane 902 is a plane that includes the closed negative spaces between the branches that define the aperture 810, as previously described. In one embodiment, the mouth plane 902 extends in an oblique direction relative to the support wire 106. For example, while the support wire 106 includes a longitudinally extending wire axis, the mouth plane 902 may be disposed in an oblique direction that is neither parallel nor perpendicular to the wire axis.

[0077] The angle of the oral plane 902 relative to the wire axis 402 (e.g., the oblique angle discussed above) can promote capture of the thrombus. For example, angling the oral plane 902 can provide a lateral opening through which the thrombus can more easily pass. Such oblique angles are one factor that influence the size of the gap 704 (see FIG. 7) between adjacent expansion frames 604. As previously discussed, the size of the gap 704 can influence the type of thrombus that is captured and how easily the thrombus is captured. For example, the angled mouth plane 902 can provide a large enough lead-in for a hard thrombus to roll more easily into the interior channel 812.

[0078] FIG. 10 shows a perspective view of the thrombus trap according to the embodiment. As previously mentioned, the thrombus trap 108 in the thrombus removal device 100 can have a variety of shapes. In one embodiment, one or more of the expansion frames 604 include a plurality of struts 230 that extend distally of the frame cell ring 802. The struts 230 can extend distally from the distal end of the frame cell ring 802. For example, the struts 230 can extend from peaks 1004 or valleys 1006 of the cell pattern at the distal end. Struts 230 may be bifurcated, as shown, to extend to multiple ends at the distal frame end 706. Struts 230 may also be integral segments, such as straight posts, having a single proximal end at the frame cell ring 802 and a single distal end at the distal frame end 706.

[0079] FIG. 11 shows a perspective view of a filter to be attached to a thrombus trap according to an embodiment. The thrombus removal device 100 can include a filter 232 for capturing thrombus passing distally of the expansion frame 604. In one embodiment, the filter 232 is coupled to the frame cell ring 802. For example, the filter 232 is attached to a strut 230 that extends distally from the frame cell ring 802. The filter 232 can have a distally converging shape. More specifically, the filter 232 can extend distally from a proximal filter end 1102 to a distal filter end 1104, and the proximal filter end 1102 can have a larger transverse dimension than the distal filter end 1104. The converging shape of the filter 232 can form a closure structure to capture a thrombus or a portion of a thrombus that traverses the lumen of the blood vessel 502 and passes distal to the expansion frame 604.

[0080] In one embodiment, filter 232 includes a web or mesh structure. For example, filter 232 is formed from polymeric or metallic filaments woven into a web or knitted into a mesh having a distally converging structure, such as a cone shape. The web or mesh structure of the filter 232 may have a porosity that allows blood to pass while trapping thrombus or portions of thrombus that flow distal to the expansion frame 604. In one embodiment, the web or mesh structure is formed from a shape memory material such as a nickel-titanium alloy, although the filter 232 may alternatively be formed from other materials or metals such as stainless steel.

[0081] The filter 232 may be formed from a thin sheet material having a predetermined porosity (hole density). For example, the filter 232 may be formed from a polymeric film having one or more holes formed therethrough to allow blood flow. Such a filter 232 may be free hanging at the proximal filter end 1102. More specifically, there may be no internal frame to support the filter 232. Alternatively, the filter 232 may be supported by one or more struts 230 extending distally from the expansion frame 604. In one embodiment, the struts 230 converge to a point (see FIG. 16). The freely suspended and / or internally supported filter 232 can contract during delivery of the device (thrombus removal device) and expand within the target anatomy to prevent distal migration of the thrombus.

[0082] The thrombus trap 108 includes a coil tip 1108. The coil tip 1108 extends distally from the filter 232 and is configured to be flexible and atraumatic to the vessel wall 504. The coil tip 1108 can also be radiopaque to improve visibility of the distal end of the thrombus trap 108. For example, the coil tip 1108 can be formed from stainless steel, platinum-iridium, or other radiopaque metals or materials that are visible under fluoroscopy. In one embodiment, the coil tip 1108 is bonded to the filter 232 and / or struts 230 of the expansion frame 604 by mechanical, thermal, or adhesive bonds. Such bonds may employ, for example, an adhesive, which bonds the filter 232 to the coil tip 1108.

[0083] While the filter 232 is shown as being part of the distal-most thrombus trap 108 (see, e.g., FIG. 2), it is understood that any of the thrombus traps 108 in the thrombus removal device 100 can include a respective filter 232. Additionally, any of the thrombus traps 108 (proximal-most, middle, distal-most, etc.) can have distal ends that converge to a respective distal end 1106. More specifically, any and all of the expansion frames 604 can close their distal ends by employing a cage-like or filter-like structure that traps distally migrating thrombus. For any of the thrombus trap configurations described herein, the distal geometry of each thrombus trap may be the same or different relative to the other thrombus traps.

[0084] 12 shows a schematic diagram of an embodiment of a thrombectomy device deployed in a curved vessel, which visually illustrates the benefits of the eccentrically supported expansion frame 604 and undulating support wires 106, as previously described. When the thrombus removal device 100 is deployed within the blood vessel 502 , each thrombus trap 108 is attached to the support wire 106 by a stem extending from a joint 606 such that it has a different clocking (angle) relative to the central axis 510 of the blood vessel 502 . For example, in the illustrated embodiment, the thrombus removal device 100 has four thrombus traps 108, each with a joint 606 and stem clocked 90 degrees differently counterclockwise from the adjacent stem. Specifically, the most proximal thrombus trap 108 has a stem at 0 degrees (at the bottom of the vessel wall 504) relative to the central axis 510, the second thrombus trap 210 adjacent to the most proximal thrombus trap 108 has a stem at 90 degrees (90 degrees counterclockwise about the central axis 510), the third thrombus trap 218 adjacent to the second thrombus trap 210 has a stem at 180 degrees, and the most distal thrombus trap 108 adjacent to the third thrombus trap 218 has a stem at 270 degrees. As previously described, the distal segment 304 of the support wire 106 is connected to the thrombus trap 108 by the joint 606 along and / or in a serpentine or spiral manner about the central axis 510. More specifically, the support wire 106 is pressed against the vessel wall 504 at each joint location that is alternately clocked relative to the central axis 510. This allows the support wire 106 to extend through the expansion frame 604 offset from the central axis 510 of the vessel 502. This offset position opens up the central lumen of the vessel 502 and the interior channel 812 of the expansion frame 604, effectively allowing the captured thrombus to move through the gaps 704 (see FIG. 7 ) between the thrombus traps 108 and into the interior channel 812.

[0085] 13 is a schematic diagram showing an embodiment of a thrombus removal device being pulled into a bend in a tortuous vessel, which visually illustrates the advantage of the independently attached thrombus trap 108, as previously described. The expansion frames 604 are connected to the support wires 106 but are not directly connected to each other. Thus, the independently supported thrombus traps 108 have degrees of freedom relative to each other such that local deformation of an individual expansion frame 604 occurs without global deformation of one or more of the other expansion frames 604. That is, deformation of one expansion frame 604 does not necessarily affect the other expansion frames 604.

[0086] In one embodiment, when the thrombus removal device 100 is deployed in a tortuous blood vessel 502, one or more thrombus traps 108 may be drawn across bends in the blood vessel. More specifically, the support wire 106 is retracted through the blood vessel 502 to retrieve the thrombus trap 108 (and the thrombus trapped by the thrombus trap), and such retraction of the support wire 106 can cause a deformation load 702 to be applied to one of the expansion frames 604. As previously discussed, the deformation load 702 may have a radial component, but when retracting the thrombus trap across a bend, it may have an axial component that stretches the expansion frame 604 located at the bend. More specifically, as shown in FIG 13, tension caused by a proximal load applied to the joint 606 of the deformed thrombus trap 108 and a distal load applied by a counter force against the vessel wall 504 may stretch the thrombus trap 108. Such deformation load 702 may cause the stretched expansion frame 604 to expand in length and, at the same time, to contract in diameter. As a result of the contraction in diameter, the expansion frame 604 may lose contact with the vessel wall 504. However, the other thrombus traps 108 remain unstretched despite the stretching of the thrombus trap 108 at the bend because they are independently attached to the support wire 106. Thus, the other thrombus traps 108 do not lose contact with the vessel wall 504. That is, the deformation of the thrombus trap 108 is localized (minimized) to the thrombus trap 108 at the bend, while the vessel 502 proximal and distal to the bend is protected by the adjacent thrombus traps 108. As a result, the thrombus 1302 pushed out from the extended thrombus trap 108 or detached in the blood vessel lumen and flowing downstream can be captured by the adjacent thrombus trap 108. Thus, such an independently attached thrombus trap 108 makes it possible to efficiently capture the entire thrombus 1302 and efficiently retrieve the thrombus from the target anatomical structure.

[0087] FIG. 14 shows a flowchart of a method for manufacturing a thrombus removal device according to an embodiment. The methods described herein are provided by way of example, and one of ordinary skill in the art may practice such methods using alternative and / or additional manufacturing steps to provide the above-described thrombus removal device 100.

[0088] In step 1402, the supporting wire 106 is formed. In one embodiment, the supporting wire 106 is manufactured by grinding a wire (e.g., a shape memory alloy wire) to form a distal segment 304 that transitions to a proximal segment 302 at a first location 209. As previously described, the supporting wire 106 can include multiple transitions to provide a wire that tapers continuously or stepwise from the proximal wire end 110 to the distal wire end 112. For example, the distal segment 304 can have a smaller diameter than the proximal segment 302. Thus, the supporting wire 106 can have a shape that decreases in stiffness in the distal direction.

[0089] In one embodiment, instead of (or in addition to) grinding the supporting wire 106, the supporting wire 106 can be formed from multiple wire segments that are joined at discrete locations. The wire segments can be joined using joints 606 by mechanical, thermal, or adhesive means. The distal wire segments can have a smaller diameter than the proximal wire segments to provide a distally decreasing stiffness profile.

[0090] In step 1404, a first thrombus trap 202 is attached to a first location 209 of the support wire 106. The first thrombus trap 202 can be attached to the support wire 106 by a joint 606 by mechanical, thermal, or adhesive means, such as a crimped marker band embedded in adhesive, as previously described. When attaching the first thrombus trap 202, the thrombus trap 108 is oriented to have the stem 602 of the first thrombus trap 202 extending from the support wire 106 at a first circumferential position (e.g., a first clocking) relative to the wire axis 402. With this clocking, the first thrombus trap 202 has a radial plane that extends in a first radial direction through the wire axis 402 and the trap axis 416.

[0091] In step 1406, a second thrombus trap 210 is attached to the support wire 106 at a second location 217. The second thrombus trap 210 can be attached to the support wire 106 by a joint 606 by mechanical, thermal, or adhesive means, such as a crimped marker band embedded in adhesive, as previously described. The second location 217 can be longitudinally offset from the first location 209 and can be located distal or proximal to the expansion frame 604 of the first thrombus trap 202. When attaching the second thrombus trap 210, the thrombus trap 108 is oriented to have the stem 602 of the second thrombus trap 210 extending from the support wire 106 at a second circumferential position (e.g., a second clocking) that is different from the first circumferential position. This clocking allows the second thrombus trap 210 to have a radial plane that extends in a second radial direction through the wire axis 402 and the trap axis 416 that is circumferentially offset from the first radial direction. Thus, the first thrombus trap 202 and the second thrombus trap 210 can be independently and eccentrically attached to the support wire 106. Additionally, the expansion frames 604 can be non-concentrically supported on the support wire 106 relative to each other.

[0092] In step 1408, a radiopaque marker 310 is attached to the support wire 106 at the first location 209 and / or the second location 217. The radiopaque marker 310 can mechanically couple the stem 602 of the expansion frame 604 to the support wire 106. For example, the radiopaque marker 310 can be a marker band that is crimped around the stem 602 and the support wire 106. The radiopaque marker 310 can also be radiopaque particles, ink, or other structures that are adhesively adhered to the support wire 106 to provide feedback to the operator of the position of the joint 606.

[0093] FIG. 15 shows a flowchart of a method for removing a thrombus from a blood vessel using the thrombus removal device according to the embodiment. In step 1502, the thrombus removal device 100 is introduced into a blood vessel 502 containing a thrombus 1302. First, a guidewire is passed through the blood vessel 502 to a target area within the narrow vessel that is at least partially occluded by the thrombus 1302. A microcatheter can be tracked over the guidewire such that the distal end of the microcatheter is located distal to the thrombus 1302. Once the microcatheter is in position, the guidewire is retracted and removed from the microcatheter. The thrombus removal device 100 is then advanced through the lumen of the microcatheter until the distal end 1106 of the thrombus removal device 100 is located near or distal to the distal end of the microcatheter. When the thrombus removal device 100 is introduced into the blood vessel 502, the microcatheter can hold the thrombus trap 108 in a constrained configuration. That is, the lumen of the microcatheter has a smaller diameter than the thrombus trap 108 in its expanded state, and thus the expansion frame 604 can be introduced into the blood vessel 502 through the microcatheter in an unexpanded state.

[0094] In step 1504, the multiple thrombus traps 108 described above are deployed. When forward pressure is applied to the support wire 106 of the thrombus removal device 100 while the microcatheter is being retracted, the thrombus traps 108 are deployed from the distal end of the microcatheter to abut against the vessel wall 504 of the blood vessel 502. Specifically, the expansion frame 604 of the thrombus trap 108 can transition to an expanded state (FIG. 1). In this expanded state, the expansion frame 604 is in close contact with the vessel wall 504. Because the expansion frames 604 are eccentrically supported on the supporting wires 106, when the expansion frames 604 deform into a concentric arrangement within the vessel (FIG. 12), each expansion frame 604 presses against the vessel wall 504 in a different transverse direction. The offset arrangement of the non-concentrically supported expansion frames 604 biases the supporting wires 106 off-center toward the vessel wall 504. Specifically, the supporting wires 106 will extend through the vessel 502 offset from the central axis 510 of the vessel 502.

[0095] After expanding the thrombus trap 108, the thrombus removal device 100 may be left in place for several minutes to allow the thrombus 1302 to engage the expansion frame 604. The support wire 106 is then pulled, at step 1506, to retract the thrombus removal device 100 to further engage, capture, or entrap the thrombus 1302 in the expansion frame 604. The support wire 106 is withdrawn until the thrombus trap 108 and entrapped thrombus 1302 are removed from the target vasculature.

[0096] 16 shows a top view of a distal portion of a thrombus removal device with multiple thrombus traps according to another embodiment. The distal working region 104 of the thrombus removal device 100 includes several features that are alternative to the previously described embodiments. Such features will not be repeated with respect to FIG. 16 for the sake of brevity.

[0097] In one embodiment, the distal working region 104 includes a plurality of thrombus traps 108 having longitudinally arranged successive expansion frames 604 (204, 212, 220). For example, the second expansion frame 212 is distal to the first expansion frame 204. Similarly, the third expansion frame 220 is distal to the second expansion frame 212. In the embodiment shown in FIG. 2, the thrombus traps 108 are arranged so that they do not overlap longitudinally, with each joint 606 of the thrombus traps 108 being located distal to the immediately proximal thrombus trap 108. However, as shown in FIG. 16, the thrombus traps 108 can be arranged so that they at least partially overlap longitudinally. For example, the second thrombus trap 210 is coupled to the support wire 106 by the second stem 214 at a location proximal to the distal frame end 706 of the first expansion frame 204. Specifically, the second stem 214 is attached to the support wire 106 at the second joint 216 that is proximal to the first expansion frame 204.

[0098] The overlap of the thrombus traps 108 is facilitated by an elongated stem 602 that extends proximally from the more distal extension frame 604 (220) and connects to the support wire 106 at a more proximal location than the more proximal extension frame 604 (212). This elongated stem 602 can increase the flexibility and mobility of the extension frame 604 (212) relative to the support wire 106. That is, although the extension frame 604 (212) is shown as being concentrically disposed along the support wire 106, it is hinged outwardly (radially) at joint 606 (216) to be non-concentrically (and eccentrically) supported relative to the support wire 106 (see FIG. 17 ).

[0099] Here, connecting the expansion frames 604 at joints 606 outside the internal channels 812 of adjacent expansion frames 604 (see FIG. 6 ) can contribute to an optimal packing ratio of the thrombus removal device 100 in addition to providing good elasticity and flexibility of the expansion frames 604 relative to the support wires 106. As previously discussed, locating the joint 606 on a support wire 106 that is not radially inward of the frame cell ring 802 allows the frame cell ring 802 to contract to a smaller dimension during delivery. That is, locating the joint 606 proximal to the expansion frame 604 (220) can improve the delivery of the thrombectomy device.

[0100] 16, one or more of the thrombus traps 108 of the thrombus removal device 100 can have a closed distal end. For example, the third thrombus trap 218 (the most distal thrombus trap) includes a plurality of struts 230 that project distally from the frame cell ring 802. The struts 230 can converge at the distal end 1106 to form a closed cage-like structure. More specifically, the cage-like structure formed by the struts 230 provides a funnel or cone-shaped profile that permits blood flow while providing some resistance to distal flow of a thrombus 1302 (see FIG. 13) through the blood vessel 502.

[0101] FIG. 17 shows a schematic diagram of a thrombus removal device including a support wire with one or more bends, according to an embodiment. The undulating and / or spiralling distal segment 304 (see FIG. 3) of the supporting wire 106 can include one or more bends 1702. Each bend 1702 results from a change in curvature of the supporting wire 106 along the wire axis 402 in the distal direction. The bend 1702 can coincide with the location where the thrombus trap 108 is attached to the support wire 106. For example, a wavy portion exists at the peak of the first location 209. The first location 209 is the location where the first thrombus trap 202 is attached to the support wire 106 by the first joint 208. Similarly, a wavy portion exists at the second location 217, which is the valley just distal to the peak. The second location 217 is the location where the second thrombus trap 210 is attached to the support wire 106 by the second joint 216.

[0102] The bend 1702 along the support wire 106 can result from the interaction between the thrombus trap 108 and the vessel wall 504. For example, the helical path of the support wire 106 described above can pass through the joint 606 (208), and thus the bend 1702 results from the support wire 106 assuming a particular shape as it extends from one joint 606 (208) to the other joint 216. The bend 1702 may also be caused by a direct action of the thrombus trap 108 itself. For example, the thrombus trap 108 may have a stem hole 1704 (see FIG. 8 ) that passes near the stem 602 (e.g., the proximal stem end 804). The support wire 106 may be threaded through the stem hole 1704 ( FIG. 8 ), and an angle may naturally occur between the stem 602 and the support wire 106 at the stem hole 1704. Additionally, when the joint 606 is formed by crimping a marker band around the support wire 106 and stem 602, the joint 606 may create a local bending moment in the support wire 106 at the stem hole 1704. This bending moment causes the support wire 106 to bend, creating a bend 1702 at the location of the joint 606. In this manner, the thrombus removal device 100 can have a support wire 106 with a bend 1702 for each of the thrombus traps 108 attached to the distal segment 304 when deployed in free space or within the blood vessel 502.

[0103] FIG. 18 shows a top view of a distal portion of a thrombus removal device having multiple thrombus traps deployed in free space, according to an embodiment. The thrombus removal device 100 includes a plurality of thrombus traps 108 attached to the support wire 106 and having respective extension frames 604 (204, 212). For example, the thrombus traps 108 include a first thrombus trap 202 and a second thrombus trap 210 independently attached to the support wire 106. Because the thrombus removal device 100 is deployed in free space 1800 (e.g., unconstrained by surrounding surfaces), the extension frames 604 (204, 212) of each thrombus trap 108 are in a non-concentric relationship with each other.

[0104] In one embodiment, the second thrombus trap 210 is the most distal thrombus trap 1802. The most distal thrombus trap 1802 has a second expansion frame 212 and may include a frame cell ring of the expansion frame as previously described. As previously described in FIG. 11, the frame cell ring may support a filter (not shown) for trapping debris such as clots. Such a filter may be attached to the distal end of the distal thrombus trap 1802 and may include a mesh or web structure. Such a web structure may have a denser surface area than the second expansion frame 212, thereby allowing debris flowing downstream in the blood vessel 502 to be trapped in the filter.

[0105] One or more of the thrombus traps 108 in the thrombus removal device 100 can have a segmented expansion frame 604 (212). In one embodiment, the most distal thrombus trap 1802 has a segmented body 1804. More specifically, the expansion frame is divided into a number of segments, with the segmented body 1804 having a proximal frame segment 1806 and a distal frame segment 1808. Each frame segment is connected by a hinge 1810 and may be separated from one another by gaps 1812 between the segments at all locations other than the hinges 1810. The structure and function of such segmented expansion frames 604 (212) are described further below.

[0106] FIG. 19 shows a plan view of a distal portion of a thrombus removal device having multiple thrombus traps according to an embodiment, deployed within a blood vessel. When the thrombus removal device 100 is deployed in the blood vessel 502 with the expansion frame 604 (204, 212) facing the blood vessel wall 504 (the blood vessel wall is not shown in FIG. 19 ), the expansion frame 604 (204, 212) is biased (pressed) to be concentric with each other. As in the above-described embodiment, when the thrombus removal device 100 is deployed in the blood vessel 502 with the expansion frame 604 (204, 212) biased against the blood vessel wall 504, the support wire 106 is forced to undulate and extend along the blood vessel wall 504 at a position offset from the central axis of the blood vessel 502. When the expansion frame 604 (204, 212) is biased concentrically in this manner, the average amount of bending per unit of axial length of the support wire 106 may be greater than when the expansion frame 604 (204, 212) is in a non-concentric relationship in the free space 1800.

[0107] In one embodiment, the thrombus traps 108 are concentrically aligned with one another along the vessel wall 504. The expansion frames 604 (204, 212) of the thrombus traps 108 can be closely spaced from one another. More specifically, the distance between adjacent expansion frames 604 (204, 212) (or frame segments of the same expansion frame 604 (212)) can be minimized. As previously described, the first thrombus trap 202 has a distal frame end 706 and the second thrombus trap 210 has a proximal frame end 708. The frame ends may be separated by a gap 704. The distal frame end 706 may be matched to the proximal frame end 708 such that the gap 704 is minimized. Specifically, the gap 704 between the proximal frame end 708 and the distal frame end 706 may be less than 10 mm at one or more locations around the vessel wall 504. For example, the gap 704 between the frame tip at the distal frame end 706 and the mouth at the proximal frame end 708 may be within a range of 1-10 mm (e.g., 1-5 mm).

[0108] The contour of the distal frame end 706 may have the same shape as, run parallel to, and / or match the contour of the proximal frame end 708. Here, the contours of these frame ends are determined by the contour or shape of an imaginary spline passing through the extension frame 604 (204, 212) at each end. For example, the contour of the distal frame end 706 may be determined by an imaginary spline extending through the distal-most point of each of the distal cells (e.g., cell tips) that make up the first thrombus trap 202. Similarly, the contour of the proximal frame end 708 may be determined by an imaginary spline extending through the struts that define the mouth of the second thrombus trap 210. These contours may closely match or match each other, as shown by the contours. More specifically, the first thrombus trap 202 may be adjacent to the second thrombus trap 210 without the thrombus traps actually touching. Thus, each thrombus trap 108 can match or mate with one another to approximate a continuous cylindrical body, although there may be gaps 704 separating the body segments.

[0109] The thrombus traps 108 and / or segments of the thrombus traps 108 can be closely spaced to maximize the frame surface area available for engaging the thrombus along the vessel wall 504. However, as previously discussed, it is beneficial to provide a path for hard thrombus to travel from the vessel wall 504 toward the lumen of the thrombus trap. In one embodiment, the struts that make up the cells at the distal frame end 706 of the first thrombus trap 202 are adapted to flex radially inward. More specifically, the frame cells are sufficiently flexible such that when a hard thrombus presses against the distal frame end 706, the frame cells can deform radially inward. In other words, the distal end of the thrombus trap 108 folds inward, allowing the hard thrombus to pass through the lumen of the thrombus trap 108. Thus, minimizing the axial distance between adjacent thrombus traps 108 in this manner provides an overall structure that can effectively trap soft thrombus while still allowing hard thrombus to be trapped within the thrombus traps 108.

[0110] FIG. 20 shows a perspective view of the most distal thrombus trap of the thrombus removal device according to an embodiment. In the distal-most thrombus trap 1802, the segmented body 1804 can include frame segments that closely match one another. For example, the proximal frame segment 1806 has a distal segment end 2002 that closely matches a proximal segment end 2004 of the distal frame segment 1808. The terminology and function of adjacent frame segments are substantially similar to the description of adjacent thrombus traps 108 discussed above. More specifically, the distal segment end 2002 can be separated from the proximal segment end 2004 by an inter-segment gap 1812, which is substantially similar to the gap 704 between the distal frame end 706 and the proximal frame end 708 discussed above. The inter-segment gap 1812 can separate the frame segments at all locations circumferentially about the segmented body 1804, except where the hinge 1810 connects the distal frame segment 1808 to the proximal frame segment 1806.

[0111] As seen from the perspective view, the hinge 1810 is provided at a connection point between the tail portion 2008 of the distal frame segment 1808 and a frame cell ring at the distal end of the proximal frame segment 1806. The frame segments may be integrally formed (e.g., cut from a single metal tube), such that the hinge 1810 can function as a connector, link, or other connecting element between the proximal frame segment 1806 and the distal frame segment 1808.

[0112] FIG. 21 shows a side view of multiple thrombus traps deployed within a blood vessel, according to an embodiment. When the thrombus removal device 100 is deployed in a blood vessel, the expansion frame 204 and the frame segments 1806, 1808 can be concentrically aligned with each other under the inward pressure exerted by the vessel wall 504 (see FIG. 5). In the absence of an axial load on the expansion frame 604 (204) via the support wire 106, the gaps 704 between adjacent thrombus traps 108 and the gaps 1812 between the frame segments can be minimal. For example, adjacent contours of the expansion frame and frame segments can match each other and be separated by gaps 704, 1812 of between 1-10 mm (e.g., 1-5 mm). This allows the thrombus traps 108 to function as a continuous cylindrical structure that uniformly abuts against the vessel wall 504 to retain the thrombus.

[0113] FIG. 22 shows another side view of multiple thrombus traps deployed within a blood vessel according to an embodiment. When a deformation load is applied to the support wire 106 (e.g., an axial load to retract the support wire 106 and thrombus trap 108 through the blood vessel 502), the deformation load causes the frame segments of the segment body 1804 (see FIG. 20 ) and / or the independent thrombus traps 108 to tilt relative to one another. More specifically, the gaps 704 between adjacent thrombus traps 108 and / or the segment gaps 1812 between adjacent frame segments will increase. Such tilting due to the independently attached and / or hinged structures may occur due to flexibility due to the joints along the support wire 106 and / or the hinges 1810 between the frame segments.

[0114] The axial load retracting the support wires 106 described above acts in a distributed manner through the framework such that the individual frames and frame segments maintain their cylindrical shape and rock outward relative to one another, rather than stretching and becoming smaller in diameter. More specifically, the segments tilt but do not lose their contour. The constituent segments can splay outward to compress a thrombus within the vessel 502. Such tilted motion is particularly beneficial around bends in tortuous vessels. By limiting the axial extension of the segments as the thrombus removal device 100 is deployed around bends in tortuous vessels, the segments can maintain contact between the vessel wall 504 and each of the segments. Thus, the segments can maintain contact with the thrombus along the vessel wall 504 and better engage the thrombus.

[0115] The tilting action of the hinged frame segments, in addition to engaging the thrombus around a bend in the vessel, can provide an opening for hard thrombus to enter the lumen of the thrombus trap 108. More specifically, the widening gaps between the component segments allow hard thrombus to pass radially inward through the lumen. Thus, in conjunction with the above description, the thrombus removal device 100 can incorporate one or more thrombus traps 108 having a segmented body 1804, allowing each frame segment to be pulled (retracted) through the blood vessel 502 with minimal stretch and opening to trap harder thrombus while pushing softer thrombus outward with the same frame segment.

[0116] 20, as shown, one or more of the extension frames 604 may be attached with a number of frame markers 2010. The frame markers 2010 may improve the visibility of these attached extension frames 604. More particularly, the frame markers 2010 may provide visual feedback to the user under fluoroscopy to allow for the location of the thrombus trap 108 within the target anatomy. Such frame markers 2010 can be made from a radiopaque material such as platinum iridium. The frame markers 2010 may be located along the distal-most frame cell ring 802 (see FIG. 8 ) of the thrombus removal device 100. In one embodiment, the frame markers 2010 are attached to one or more of the struts at the distal end of each thrombus trap 108 of the thrombus removal device 100.

[0117] FIG. 23 shows a perspective view of a frame marker according to an embodiment. The frame markers 2010 can be formed by electroplating a radiopaque material onto the expansion frame 604. The frame markers 2010 can also be formed as bands that are pressure bonded to the expansion frame 604. In one embodiment, the frame marker 2010 includes a marker coil 2300. The marker coil 2300 may be formed from a radiopaque wire that is wound into a coil or coiled around the struts of the expansion frame 604. Such a wire may be wound, for example, with 5-10 turns around the struts of the distal thrombus trap 1802. Solder may be applied around the periphery of the marker coil 2300 to secure the coil to the struts of the thrombus trap 1802. Additionally, as shown, the coil may be soldered to provide a bulbous shape at both ends to provide an atraumatic surface that will not damage the vessel wall 504 during use.

[0118] FIG. 24 illustrates a top view of a radiopaque coil attached to a support wire of a thrombus removal device, according to an embodiment. The thrombus removal device 100 can include a radiopaque coil 2400 mounted on the support wire 106 proximal to the thrombus trap 108, in addition to a frame marker 2010 (see FIG. 20) on the distal-most thrombus trap 1802. The radiopaque coil 2400 provides visual feedback to the user under fluoroscopy to aid in locating the proximal region of the thrombus removal device 100. As previously mentioned, the support wire 106 can include a distal segment 304 that supports the thrombus traps 108, and a proximal segment 302 located proximal to the distal segment 304. More specifically, the proximal segment 302 is located proximal to the thrombus traps 108, and the distal segment 304 extends through the thrombus traps 108 (and at least one of the thrombus traps 108 is mounted on the distal segment 304).

[0119] In one embodiment, the proximal segment 302 and the distal segment 304 are coupled to a radiopaque coil 2400 (see FIG. 24). As an example, the proximal segment 302 can have a distal end coupled to the radiopaque coil 2400 at a coil joint 2402. The distal segment 304 can also be coupled to the radiopaque coil 2400 at a coil joint 2402. For example, the coil joint 2402 may be formed by providing a solder joint between the radiopaque coil 2400, the proximal segment 302, and the distal segment 304. The distal segment 304 may extend distally through the radiopaque coil 2400. In one embodiment, the thrombus trap 108 is connected to the distal segment 304 at a first joint 208, and the distal segment 304 extends distally to a connection point with one or more additional thrombus traps 108 by a joint distal to the first joint 208.

[0120] The radiopaque coil 2400 may increase the visibility of the thrombectomy device 100 and may provide a stronger joint between the proximal and distal segments 302, 304. Additional joints may be formed along the radiopaque coil 2400. For example, solder joints may be formed at the intermediate and / or distal ends of the radiopaque coil 2400 connecting the radiopaque coil 2400 to the proximal segment 302 or the distal segment 304. The proximal segment 302 of such a supporting wire 106 may have a larger diameter than the distal segment 304 of the supporting wire 106, as previously described.

[0121] The method of taking in a thrombus using the thrombus removal device 100 shown in Figs. 18 to 24 can be the same as or similar to the method described above with reference to Fig. 15. Specifically, first, the thrombus removal device 100 is introduced into a blood vessel 502 containing a thrombus. In a free state, the thrombus traps 108 may shift to a non-concentric relationship with each other in order to maintain their shape, but when the thrombus traps 108 are deployed within the blood vessel 502, the expansion frame 604 (204, 212) of the thrombus traps 108 can be brought into contact with the blood vessel wall 504, and the blood vessel wall urges the expansion frame 604 (204, 212) to be concentric with each other due to its restraining force. The thrombus removal device 100 is then retracted, for example by pulling the support wires 106, to capture the thrombus in the expansion frame 604 (204, 212). As the thrombus removal device 100 is retracted, the individual thrombus traps and / or frame segments of the segmented body 1804 can tilt relative to one another. This tilting action limits the axial extension of the individual bodies, causing each constituent segment to press the thrombus outward, opening a wide gap in the lumen of the thrombus trap 108 to receive the hard thrombus. As a result, according to this method of catching a thrombus, it is possible to provide an excellent thrombus removal device 100 that can effectively catch a thrombus while minimizing the expansion of the frame structure.

[0122] Hereinafter, embodiments will be described according to the claims. In one embodiment, the thrombus removal device comprises: A supporting wire; a plurality of thrombus traps independently attached to the support wire; Each of the thrombus traps has an expansion frame eccentrically supported on the support wire; When the multiple thrombus traps are deployed within a blood vessel, the expansion frame is configured to abut against a vascular wall of the blood vessel and the support wire is configured to extend through one or more of the expansion frames at a position offset from a central axis of the blood vessel.

[0123] In one embodiment, a thrombus removal device includes: The expansion frames are supported by the support wires in a non-concentric manner with respect to each other, When the multiple thrombus traps are deployed within a blood vessel, the expansion frames press against the vessel wall in different transverse directions.

[0124] In one embodiment, a thrombus removal device includes: When the expansion frame abuts against the vessel wall, the support wire extends helically along the vessel wall.

[0125] In one embodiment, a thrombus removal device includes: Each of the thrombus traps includes a stem that connects the expansion frame to the support wire at a joint; and The joints are spaced longitudinally along the support wires such that a deformation load applied to one expansion frame is not transferred to the other expansion frame.

[0126] In one embodiment, a thrombus removal device includes: the deformation load is caused by retracting the support wire through the blood vessel; and The multiple thrombus capture devices are each independently attached to the support wire so that when one of the expansion frames is stretched or not in contact with the blood vessel wall due to the deformation load, the other expansion frames are not stretched or in contact with the blood vessel wall.

[0127] In one embodiment, a thrombus removal device includes: The plurality of thrombus traps include a first thrombus trap having a first expansion frame and a first stem; a second thrombus trap having a second expansion frame and a second stem; The second expansion frame is distal to the first expansion frame, and a second stem is coupled to the support wires at a respective joint proximal to the first expansion frame.

[0128] In one embodiment, a thrombus removal device includes: Additionally, a radiopaque marker is provided at the joint.

[0129] In one embodiment, a thrombus removal device includes: Each of the thrombus traps has a respective radial plane that includes a respective trap axis and a wire axis of the support wire, and the radial planes are angularly offset from one another about the support wire.

[0130] In one embodiment, a thrombus removal device includes: The radial planes are uniformly angularly distributed about the support wire.

[0131] In one embodiment, a thrombus removal device includes: Each of the expansion frames includes a frame cell ring coupled to the stem.

[0132] In one embodiment, a thrombus removal device includes: The stem includes a plurality of branches that extend between the joint and a proximal ring end of the frame cell ring to provide access to an interior channel of the expansion frame.

[0133] In one embodiment, a thrombus removal device includes: The through port has an opening plane that extends obliquely relative to the support wire.

[0134] In one embodiment, a thrombus removal device includes: One or more of the expansion frames include a plurality of struts that extend distally from the frame cell ring and converge at a distal tip.

[0135] In one embodiment, a thrombus removal device includes: Further included is a filter coupled to the frame cell ring.

[0136] In one embodiment, a thrombus removal device includes: The supporting wire is a proximal segment proximal to the plurality of thrombus traps; a distal segment extending through one or more of the plurality of thrombus traps; The proximal segment is straight and the distal segment is non-linear.

[0137] In one embodiment, a thrombus removal device includes: The distal segment includes one or more bends.

[0138] In one embodiment, a thrombus removal device includes: The one or more bends correspond to locations where the multiple thrombus traps are attached to the support wire.

[0139] In one embodiment, a thrombus removal device includes: The proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

[0140] The method according to one embodiment comprises the following steps a and b. Attach a first thrombus trap to a support wire, where the first thrombus trap includes a first expansion frame eccentrically supported on the support wire at a first location. b. Attach a second thrombus trap to the support wire, wherein the second thrombus trap includes a second expansion frame eccentrically supported on the support wire, and the first and second expansion frames are non-concentrically supported relative to one another on the support wire.

[0141] The method according to one embodiment further comprises the following steps. The support wire is ground to form a distal segment that transitions to a proximal segment at the first location, where the distal segment has a smaller diameter than the proximal segment.

[0142] The method according to one embodiment further comprises the following steps. A radiopaque marker is attached to the support wire at the first location.

[0143] A method for removing a thrombus from a blood vessel according to one embodiment comprises the following steps a to c. Introducing a mechanical thrombus removal device into a vessel containing a thrombus, where the thrombus removal device includes a support wire and a plurality of thrombus traps independently attached to the support wire, each of the thrombus traps including an expanding frame that is introduced into the vessel in an unexpanded state. b. deploying the plurality of thrombus traps and transitioning the expansion frame to an expanded state in abutment with a vessel wall of the blood vessel, wherein the expansion frame is eccentrically supported on the supporting wire such that the supporting wire extends through the blood vessel offset from a central axis of the blood vessel when the expansion frame abuts the vessel wall. c. Retracting the thrombus removal device and capturing the thrombus in the expansion frame.

[0144] In one embodiment, a method for removing a thrombus from a blood vessel comprises: The expansion frames are supported non-concentrically relative to one another on the support wires such that when the multiple thrombus traps are deployed, the expansion frames each press against the vessel wall in a different transverse direction.

[0145] In one embodiment, the thrombus removal device comprises: A supporting wire; a plurality of thrombus traps independently attached to the support wire, each having an expansion frame; When the thrombus removal device is deployed in free space, the expansion frames are non-concentric with respect to each other, whereas when the thrombus removal device is deployed within a blood vessel and the expansion frames are in abutment against the vessel wall of the blood vessel, the expansion frames are urged to be concentric with each other.

[0146] In one embodiment, a thrombus removal device includes: the plurality of thrombus traps includes a first thrombus trap proximal to a second thrombus trap; The first thrombus trap has a distal frame end and the second thrombus trap has a proximal frame end, the distal frame end being alignable with the proximal frame end.

[0147] In one embodiment, a thrombus removal device includes: The gap between the distal frame end and the proximal frame end when aligned is less than 10 mm.

[0148] In one embodiment, a thrombus removal device includes: The distal-most thrombus trap includes a frame cell ring and a filter coupled to the frame cell ring.

[0149] In one embodiment, a thrombus removal device includes: The supporting wire is a proximal segment located proximal to the plurality of thrombus traps; a distal segment extending through one or more of the plurality of thrombus traps; The proximal and distal segments are coupled to a radiopaque coil attached to the support wire.

[0150] In one embodiment, a thrombus removal device includes: The proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

[0151] In one embodiment, the thrombus removal device further comprises: A plurality of frame markers are provided attached to one or more of the expansion frames, the plurality of frame markers being radiopaque.

[0152] In one embodiment, a thrombus removal device includes: When the thrombus removal device is deployed within the blood vessel and the expansion frame abuts against the vessel wall, the support wire is urged to undulate along the vessel wall while being offset from the central axis of the blood vessel.

[0153] In one embodiment, the thrombus removal device comprises: A supporting wire; a first thrombus trap attached to the support wire and having a first expansion frame; a second thrombus trap attached to the support wire and having a second expansion frame; the second expansion frame of the second thrombus trap includes a segmented body having a proximal frame segment connected to a distal frame segment by a hinge; When the thrombus removal device is deployed in free space, the first expansion frame and the second expansion frame are non-concentric with each other, whereas when the thrombus removal device is deployed within a blood vessel and the first expansion frame and the second expansion frame abut against the vascular wall of the blood vessel, the first expansion frame and the second expansion frame are forced concentrically with each other.

[0154] In one embodiment, a thrombus removal device includes: the proximal frame segment having a distal segment end and the distal frame segment having a proximal segment end; The distal segment end is separated from the proximal segment end by a circumferential gap and the distal frame segment is connected to the proximal frame segment only by the hinge.

[0155] In one embodiment, a thrombus removal device includes: When a deformation load is applied to the support wire to retract the support wire through a blood vessel, the deformation load causes the distal and proximal frame segments of the segmented body to tilt about the hinge to increase the circumferential gap between the frame segments.

[0156] In one embodiment, a thrombus removal device includes: the first thrombus trap is located proximally relative to the second thrombus trap; The first thrombus trap has a distal frame end and the second thrombus trap has a proximal frame end, the distal frame end being alignable with the proximal frame end.

[0157] In one embodiment, a thrombus removal device includes: The gap between the distal frame end and the proximal frame end when aligned is less than 10 mm.

[0158] In one embodiment, a thrombus removal device includes: The second thrombus trap includes a frame cell ring and further comprises a filter coupled to the frame cell ring.

[0159] In one embodiment, a thrombus removal device includes: When the thrombus removal device is deployed within the blood vessel and the expansion frame abuts against the vessel wall, the support wire is urged to undulate along the vessel wall while being offset from the central axis of the blood vessel.

[0160] A method for removing a thrombus from a blood vessel according to one embodiment includes the following steps a to c. Introducing a mechanical thrombus removal device into the vessel containing the thrombus, where the thrombus removal device includes a support wire and a plurality of thrombus traps, each of which includes an expanding frame, the plurality of thrombus traps being independently attached to the support wire, and the expanding frames being non-concentric with respect to one another when the thrombus removal device is deployed in free space. b) deploying the plurality of thrombus traps within the blood vessel such that the expansion frames abut against a vessel wall of the blood vessel, the expansion frames being biased concentrically relative to one another; c. The thrombus removal device is retracted, trapping the thrombus in the expansion frame.

[0161] In one embodiment, a method for removing a blood clot from a blood vessel comprises: The plurality of thrombus traps includes a first thrombus trap proximal to a second thrombus trap, the first thrombus trap having a distal frame end and the second thrombus trap having a proximal frame end, the distal frame end being alignable with the proximal frame end.

[0162] In one embodiment, a method for removing a blood clot from a blood vessel comprises: The distal-most thrombus trap includes a frame cell ring and further comprises a filter coupled to the frame cell ring.

[0163] In one embodiment, a method for removing a blood clot from a blood vessel comprises: The plurality of thrombus traps include a first thrombus trap attached to the support wire and having a first expansion frame; a second thrombus trap attached to the support wire and having a second expansion frame; The second expansion frame includes a segmented body having a proximal frame segment connected to a distal frame segment by a hinge.

[0164] In one embodiment, a method for removing a blood clot from a blood vessel comprises: When the thrombus removal device is deployed within the blood vessel and the expansion frame is in contact with the blood vessel wall, the support wire is forced to undulate along the blood vessel wall while being offset from the central axis of the blood vessel.

[0165] Each invention described in this specification is described based on these specific embodiments. Each embodiment can be modified in various ways without departing from the concept and scope of the present invention described in the claims. Therefore, the specification and drawings are not intended to limit the understanding of the present invention, but are intended to provide an illustrative understanding of the present invention.

Claims

1. 1. A mechanical thrombus removal device, comprising: A supporting wire; a plurality of thrombus traps independently attached to the support wire; Each of the thrombus traps has an expansion frame eccentrically supported on the support wire; A thrombus removal device configured such that when the multiple thrombus traps are deployed within a blood vessel, the expansion frame abuts against a vascular wall of the blood vessel and the support wire extends through one or more of the expansion frames at a position offset from a central axis of the blood vessel.

2. 2. The thrombus removal device of claim 1, The expansion frames are supported by the support wires in a non-concentric manner with respect to each other, When the plurality of thrombus traps are deployed in a blood vessel, the expansion frame presses against the blood vessel wall in different transverse directions.

3. 2. The thrombus removal device of claim 1, A thrombus removal device, wherein the support wire extends helically along the vessel wall when the expansion frame abuts the vessel wall.

4. 2. The thrombus removal device of claim 1, Each of the thrombus traps includes a stem that connects the expansion frame to the support wire at a joint; and A thrombus removal device, wherein the joints are spaced apart longitudinally along the support wire such that a deformation load applied to one of the expansion frames is not transmitted to the other of the expansion frames.

5. 5. The thrombus removal device of claim 4, the deformation load is caused by retracting the support wire through the blood vessel; and A thrombus removal device, wherein the multiple thrombus capture devices are each independently attached to the support wire so that when one of the expansion frames is stretched or not in contact with the blood vessel wall due to the deformation load, the other expansion frames are not stretched or in contact with the blood vessel wall.

6. 5. The thrombus removal device of claim 4, The plurality of thrombus traps include a first thrombus trap having a first expansion frame and a first stem; a second thrombus trap having a second expansion frame and a second stem; A thrombus removal device, wherein the second expansion frame is distal to the first expansion frame and a second stem is coupled to the support wires at a respective joint proximal to the first expansion frame.

7. 5. The thrombus removal device of claim 4, further comprising: The thrombectomy device includes a radiopaque marker at the joint.

8. 5. The thrombus removal device of claim 4, A thrombus removal device, wherein each of the thrombus traps has a respective radial plane that includes a respective trap axis and a wire axis of the support wire, and these radial planes are angularly offset from one another about the support wire.

9. 9. The thrombus removal device of claim 8, A thrombus removal device, wherein the radial planes are uniformly angularly distributed about the support wire.

10. 5. The thrombus removal device of claim 4, Each of the expansion frames includes a frame cell ring coupled to the stem.

11. 11. The thrombus removal device of claim 10, The stem includes a plurality of branches that extend between the joint and a proximal ring end of the frame cell ring to provide access to an interior channel of the expansion frame.

12. 12. The thrombus removal device of claim 11, The port has an aperture plane that extends obliquely relative to the support wire.

13. 11. The thrombus removal device of claim 10, The one or more expansion frames include a plurality of struts extending distally beyond the frame cell ring and converging at a distal tip.

14. 11. The thrombus removal device of claim 10, further comprising: A thrombus removal device comprising a filter coupled to the frame cell ring.

15. 11. The thrombus removal device of claim 10, The supporting wire is a proximal segment proximal to the plurality of thrombus traps; a distal segment extending through one or more of the plurality of thrombus traps; A thrombus removal device, wherein the proximal segment is straight and the distal segment is non-linear.

16. 16. The thrombus removal device of claim 15, The distal segment includes one or more bends.

17. 17. The thrombus removal device of claim 16, The one or more bends correspond to locations where the plurality of thrombus traps are attached to the support wire.

18. 16. The thrombus removal device of claim 15, The proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

19. A method comprising the steps of: a) and b) Attach a first thrombus trap to a support wire, wherein said first thrombus trap includes a first expansion frame eccentrically supported on said support wire at a first location. b) attaching a second thrombus trap to the support wire, wherein the second thrombus trap includes a second expansion frame eccentrically supported on the support wire, and wherein the first and second expansion frames are non-concentrically supported relative to one another on the support wire;

20. 20. The method of claim 19, further comprising the steps of: The support wire is ground to form a distal segment that transitions to a proximal segment at the first location, where the distal segment has a smaller diameter than the proximal segment.

21. 20. The method of claim 19, further comprising the steps of: A radiopaque marker is attached to the support wire at the first location.

22. A method for removing a blood clot from a blood vessel, comprising the steps of: Introducing a mechanical thrombus removal device into a vessel containing a thrombus, where the thrombus removal device includes a support wire and a plurality of thrombus traps independently attached to the support wire, each of the thrombus traps including an expansion frame that is introduced into the vessel in an unexpanded state. b) deploying the plurality of thrombus traps and transitioning the expansion frame to an expanded state abutting a vessel wall of the blood vessel, wherein the expansion frame is eccentrically supported on the supporting wire such that the supporting wire extends through the blood vessel offset from a central axis of the blood vessel when the expansion frame abuts the vessel wall. c) Retract the thrombus removal device, capturing the thrombus in the expansion frame.

23. 23. The method of claim 22, The method, wherein the expansion frames are non-concentrically supported relative to one another on the support wire such that when the multiple thrombus traps are deployed, the expansion frames each press against the vessel wall in a different transverse direction.

24. 1. A mechanical thrombus removal device, comprising: A supporting wire; a plurality of thrombus traps independently attached to the support wire, each having an expansion frame; A thrombus removal device, wherein when the thrombus removal device is deployed in free space, the expansion frames are non-concentric with each other, and when the thrombus removal device is deployed within a blood vessel and the expansion frames are in abutment against the vascular wall of the blood vessel, the expansion frames are urged to be concentric with each other.

25. 25. The thrombus removal device of claim 24, the plurality of thrombus traps includes a first thrombus trap proximal to a second thrombus trap; A thrombus removal device, wherein the first thrombus trap has a distal frame end and the second thrombus trap has a proximal frame end, the distal frame end being alignable with the proximal frame end.

26. 26. The thrombus removal device of claim 25, A thrombus removal device, wherein a gap between the distal frame end and the proximal frame end when aligned is less than 10 mm.

27. 25. The thrombus removal device of claim 24, further comprising: A thrombus removal device, wherein the distal most thrombus trap includes a frame cell ring and a filter coupled to the frame cell ring.

28. 25. The thrombus removal device of claim 24, The supporting wire is a proximal segment located proximal to the plurality of thrombus traps; a distal segment extending through one or more of the plurality of thrombus traps; The thrombectomy device, wherein the proximal and distal segments are coupled to a radiopaque coil attached to the support wire.

29. 29. The thrombus removal device of claim 28, The proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

30. 25. The thrombus removal device of claim 24, further comprising: A thrombus removal device comprising a plurality of frame markers attached to one or more of said expansion frames, said plurality of frame markers being radiopaque.

31. 25. The thrombus removal device of claim 24, A thrombus removal device, wherein when the thrombus removal device is deployed within the blood vessel and the expansion frame abuts against the blood vessel wall, the support wire is forced to undulate along the blood vessel wall while being offset from the central axis of the blood vessel.

32. 1. A mechanical thrombus removal device, comprising: A supporting wire; a first thrombus trap attached to the support wire and having a first expansion frame; a second thrombus trap attached to the support wire and having a second expansion frame; the second expansion frame of the second thrombus trap includes a segmented body having a proximal frame segment connected to a distal frame segment by a hinge; A thrombus removal device, wherein when the thrombus removal device is deployed in free space, the first expansion frame and the second expansion frame are non-concentric with each other, while when the thrombus removal device is deployed within a blood vessel and the first expansion frame and the second expansion frame abut against a vascular wall of the blood vessel, the first expansion frame and the second expansion frame are forced concentric with each other.

33. 33. The thrombus removal device of claim 32, the proximal frame segment having a distal segment end and the distal frame segment having a proximal segment end; The thrombus removal device, wherein the distal segment end is separated from the proximal segment end by a circumferential gap and the distal frame segment is connected to the proximal frame segment only by the hinge.

34. 34. The thrombus removal device of claim 33, A thrombus removal device, wherein when a deformation load is applied to the support wire to retract the support wire through a blood vessel, the distal frame segment and the proximal frame segment of the segmented body tilt about the hinge due to the deformation load to increase the circumferential gap between the frame segments.

35. 33. The thrombus removal device of claim 32, the first thrombus trap is located proximally relative to the second thrombus trap; A thrombus removal device, wherein the first thrombus trap has a distal frame end and the second thrombus trap has a proximal frame end, the distal frame end being alignable with the proximal frame end.

36. 36. The thrombus removal device of claim 35, A thrombus removal device, wherein a gap between the distal frame end and the proximal frame end when aligned is less than 10 mm.

37. 33. The thrombus removal device of claim 32, The second thrombus trap includes a frame cell ring, the thrombus removal device further comprising a filter coupled to the frame cell ring.

38. 33. The thrombus removal device of claim 32, A thrombus removal device, wherein when the thrombus removal device is deployed within the blood vessel and the expansion frame abuts against the blood vessel wall, the support wire is forced to undulate along the blood vessel wall while being offset from the central axis of the blood vessel.

39. A method for removing a blood clot from a blood vessel, comprising the steps of: Introducing a mechanical thrombus removal device into the vessel containing the thrombus, where the thrombus removal device includes a support wire and a plurality of thrombus traps, each of which includes an expanding frame, the plurality of thrombus traps being independently attached to the support wire, and the expanding frames being non-concentric with respect to one another when the thrombus removal device is deployed in free space. b) deploying the plurality of thrombus traps within the vessel such that the expansion frames abut against a vessel wall of the vessel, the expansion frames being biased concentrically relative to one another; c) Retract the thrombus removal device, trapping the thrombus in the expansion frame.

40. 40. The method of claim 39, The method, wherein the plurality of thrombus traps includes a first thrombus trap proximal to a second thrombus trap, the first thrombus trap having a distal frame end and the second thrombus trap having a proximal frame end, the distal frame end being alignable with the proximal frame end.

41. 40. The method of claim 39, The method, wherein the distal-most thrombus trap includes a frame cell ring and further comprises a filter coupled to the frame cell ring.

42. 40. The method of claim 39, The plurality of thrombus traps include a first thrombus trap attached to the support wire and having a first expansion frame; a second thrombus trap attached to the support wire and having a second expansion frame; The second expansion frame includes a segmented body having a proximal frame segment connected to a distal frame segment by a hinge.

43. 40. The method of claim 39, When the thrombus removal device is deployed within the blood vessel and the expansion frame is in abutment against the vessel wall of the blood vessel, the support wire is forced to undulate along the vessel wall while being offset from the central axis of the blood vessel.

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