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 the priority of U.S. Patent Application No. 17 / 192,786, filed on March 4, 2024, and U.S. Patent Application No. 17 / 532,891, filed on November 22, 2021, the entire contents of which are incorporated herein by reference.

Background Art

[0002] The invention according to the present disclosure relates to a mechanical thrombectomy device (thrombectomy device: hereinafter, may be referred to as a thrombectomy device) used for treating ischemic stroke, and more particularly, to a thrombectomy device used for thrombectomy procedures in the neurovascular system.

[0003] There are various devices for saving the brains of patients with acute ischemic stroke. Among these, at an early stage, there is a thrombectomy device used to remove thrombi from the neurovascular system in order to restore perfusion of the occluded artery. As this type of thrombectomy device, a coil retriever device, a suction device, and recently a stent retriever device are known.

[0004] Existing stent retriever devices are basically self-expanding stents, which can be placed in a thrombus to push the thrombus away or entangle the thrombus inside the struts (posts) of the stent. After the stent and the thrombus are mechanically integrated, they are withdrawn into the delivery catheter and removed from the patient. Important factors in the ease of use and performance of stent retriever devices include visibility under fluoroscopy, the ability to capture or engage thrombi, and the ability to hold thrombi captured or engaged when the stent is drawn through tortuous blood vessels. Deficiencies in these factors can prolong the treatment time and reduce the clinical success rate.

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] Existing stent retriever devices are not optimal in terms of visibility, thrombus engagement, and / or thrombus retention. Most current stent retriever devices are radiopaque in structure and therefore not easily visible under fluoroscopy during the procedure. Furthermore, most current stent retriever devices employ a one-piece stent body that hinders the capture and engagement of thrombi. For example, the one-piece stent body may roll over a hard thrombus, causing it to bounce off without capturing or engaging with it. Additionally, when the stent body is pulled at a bend in the blood vessel, it may stretch along its entire length, potentially causing the captured thrombus to become dislodged and lost. [Means for solving the problem]

[0006] The following describes the thrombectomy device according to the present invention, which solves the problems of the existing stent retriever devices mentioned above. In one embodiment of the present invention, the thrombectomy device includes a plurality of thrombus capturers independently supported on a support wire. For example, the support wire may have a proximal segment and a distal segment having a smaller diameter or lower rigidity than the proximal segment, and the thrombus capturers can be attached to the distal segment. More specifically, each of the thrombus capture devices may include an expandable frame (hereinafter referred to as the expandable frame) and a stem, the stem of which the expandable frame can be connected to the support wire by a joint. The joint may be a mechanical joint such as a radiopaque marker band that is crimped around the support wire and the stem, thereby allowing the joint to be visualized under fluoroscopy. Furthermore, the thrombus capture device is independently supported on the support wire by each of the joints, which are arranged longitudinally at intervals along the support wire. Therefore, even if a deformable load is applied to one of the expansion frames, that load is not transmitted to the other expansion frames. As a result, for example, when the device is pulled near a bend in a blood vessel, even if one of the expansion frames stretches and loses contact with the blood vessel wall, the other expansion frames will not stretch and lose contact with the blood vessel wall. Accordingly, the thrombus removal device according to the present invention can more effectively capture and retrieve thrombi from tortuous anatomical structures.

[0007] In the plurality of thrombus traps, the expansion frame is eccentrically supported by the support wire. For example, when the thrombus trap is deployed in free space, the expansion frame is positioned so that the trap axis of the expansion frame is not aligned with the wire axis of the support wire, while when the thrombus trap is deployed in a blood vessel, the expansion frame abuts against the blood vessel wall and is biased (pressed) against the blood vessel wall so as to be concentric. This causes the trap axis to align with the central axis of the blood vessel, and the support wire can be biased (pressed) radially outward toward the blood vessel wall. The support wire can then be offset from the central axis of the blood vessel, for example, extending spirally along the blood vessel wall through the expansion frame, opening the lumen of the blood vessel and the internal channels of the expansion frame to receive thrombi. Therefore, with the thrombectomy device of the present invention, hard thrombi do not roll between the device and the blood vessel wall and are lost downstream, but instead roll into the internal channel and are captured. As a result, such hard thrombi can be captured more effectively.

[0008] Furthermore, the expansion frames in the plurality of thrombus trappers are supported non-concentrically by the support wires. For example, when the thrombus trappers are deployed in free space, the expansion frames are arranged so that the trapper axes of the expansion frames are not aligned with each other, while when the thrombus trappers are deployed in a blood vessel, the expansion frames come into contact with the blood vessel wall and are biased (pressed) concentrically with each other. Because the expansion frames try to return to their undeformed, free state, they can generate an outward pressing force through their elastic force. Since the expansion frames are non-concentric in their free state, this outward pressing force can act on the blood vessel wall in different transverse directions (radial directions). Therefore, such a non-concentric expansion frame can increase the transverse (radial) force distributed around the blood vessel wall, thereby effectively assisting in the capture of thrombi when the thrombectomy device according to the present invention is withdrawn through the blood vessel.

[0009] The thrombus capture effect can be further enhanced by other features of the thrombus removal device of the present invention, such as a filter located at the distal end of the device, or adjacent openings of independently supported thrombus capturers. The filter may be formed from a self-expanding web or mesh that captures thrombi while allowing blood to pass distally. The opening may be adjusted by changing the spacing of the joints, the shape of the expansion frame, or other variables. Such adjustments can provide a port through which hard or soft thrombi, which are captured within the internal channel of the thrombectomy device, can pass. A method for manufacturing a thrombectomy device according to the present invention, and a method for using the thrombectomy device to remove a thrombus from a blood vessel, will be described further later.

[0010] The thrombectomy device may include a thrombus capturer having a segmented structure. For example, the most distal thrombus capturer may have a segmented body including a proximal frame segment and a distal frame segment. The frame segments may be connected by hinges, such as connectors between the frames. When an axial load is applied to the thrombectomy device (e.g., when the device retracts within a blood vessel), the frame segments can tilt around the hinge. More specifically, while retrieving a thrombus, the frame segments can tilt relative to each other while being concentrically biased. This tilting motion allows the frame segments to press outward against soft thrombi that are covering and adhering to the vessel wall, and also separates the frame segments, making it easier for hard thrombi to enter the lumen of the frame segments through the gaps between them.

[0011] The summary of the present invention described above does not exhaustively list all aspects of the invention. The present invention includes all apparatus and methods that can be implemented from all preferred combinations of the various aspects described above, the aspects disclosed in the following detailed description (Modes for Carrying Out the Invention), and the aspects specifically indicated in the claims filed with this application. Such combinations have unique advantages not specifically described above.

[0012] Novel features of the present invention are described in particular in the claims appended herein. For a better understanding of the features and advantages of the present invention, it is helpful to refer to the following detailed description (Modes for Carrying Out the Invention) illustrating exemplary embodiments to which the principles of the present invention are applied, and to the accompanying drawings. [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view showing a thrombectomy device according to an embodiment of the present invention.

[0014] [Figure 2] A plan view showing a distal portion of a thrombus removal device having a plurality of thrombus capturers according to an embodiment of the present invention.

[0015] [Figure 3] A perspective view showing a distal portion of a thrombus removal device having a plurality of thrombus capturers according to an embodiment of the present invention.

[0016] [Figure 4] An end view showing a plurality of thrombus capturers deployed in free space according to an embodiment of the present invention.

[0017] [Figure 5] An end view showing a plurality of thrombus capturers deployed in a blood vessel according to an embodiment of the present invention.

[0018] [Figure 6] A side view showing a plurality of thrombus capturers deployed in free space according to an embodiment of the present invention.

[0019] [Figure 7] A side view showing a plurality of thrombus capturers deployed in a straight blood vessel according to an embodiment of the present invention.

[0020] [Figure 8] A perspective view showing a thrombus capturer according to an embodiment of the present invention.

[0021] [Figure 9] A side view showing a thrombus capturer according to an embodiment of the present invention.

[0022] [Figure 10] A perspective view showing a thrombus capturer according to an embodiment of the present invention.

[0023] [Figure 11] A perspective view showing a filter attached to a thrombus capturer according to an embodiment of the present invention.

[0024] [Figure 12] This is a schematic diagram showing a thrombectomy device deployed within a curved blood vessel according to an embodiment of the present invention.

[0025] [Figure 13] This is a schematic diagram showing how a thrombectomy device is drawn into a bend in a tortuous blood vessel according to an embodiment of the present invention.

[0026] [Figure 14] This is a flowchart showing a method for manufacturing a thrombectomy device according to an embodiment of the present invention.

[0027] [Figure 15] This flowchart shows a method for removing a thrombus from a blood vessel using a thrombectomy device according to an embodiment of the present invention.

[0028] [Figure 16] This is a plan view showing the distal portion of a thrombectomy device having multiple thrombus capturers according to another embodiment of the present invention.

[0029] [Figure 17] This is a perspective view showing a thrombectomy device, including a support wire with one or more bent portions, according to another embodiment of the present invention.

[0030] [Figure 18] This is a plan view showing the distal portion of a thrombectomy device having a plurality of thrombus capturers deployed in free space, according to another embodiment of the present invention.

[0031] [Figure 19] This is a plan view showing the distal portion of a thrombectomy device having a plurality of thrombus capturers deployed within a blood vessel, according to another embodiment of the present invention.

[0032] [Figure 20] This is a perspective view showing the most distal thrombus capturer of a thrombectomy device according to another embodiment of the present invention.

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

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

[0035] [Figure 23] This is a perspective view showing a frame marker according to an embodiment of this model.

[0036] [Figure 24] This is a plan view showing a radiopaque coil attached to a support wire of a thrombectomy device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0037] The following describes a thrombectomy device according to an embodiment of the present invention, namely a thrombectomy device having a thrombus capturer independently and eccentrically attached to a support wire. The thrombectomy device according to this embodiment is suitable for use in the treatment of acute ischemic stroke, but is not limited to this and can be used for other purposes such as thrombectomy from other blood vessels.

[0038] Various embodiments are described with reference to the figures, but certain embodiments can be implemented without one or more of these specific details, or in combination with other known methods and configurations. The following description provides numerous specific details, such as specific configurations, dimensions, and processes, to facilitate understanding of the embodiments. On the other hand, well-known processes and manufacturing techniques are not described in particular detail to avoid obscuring the explanation. In this specification, references to "one embodiment," "embodiment," etc., mean that the specific features, structures, configurations, or characteristics described are included in at least one embodiment. Therefore, wherever the phrases "one embodiment," "embodiment," etc. appear throughout this specification, they do not necessarily refer to the same embodiment. Furthermore, specific features, structures, configurations, or characteristics can be combined in any suitable manner in one or more embodiments.

[0039] In this specification, the use of relative terms indicates relative position or direction. For example, “distal” may refer to a first direction along the longitudinal axis of the support wire or thrombus capturer. Similarly, “proximal” may refer to a second direction opposite to the first direction. However, such terms are provided to establish a relative reference frame and are not intended to limit the use or procedure of the thrombectomy device to the specific configurations described in the various embodiments below.

[0040] In one embodiment, the thrombectomy device includes a plurality of thrombus capturers attached to a support wire. Each thrombus capturer is attached independently. More specifically, each thrombus capturer includes an extension frame attached to the support wire independently of the extension frames of other thrombus capturers. Unlike conventional competing devices that stretch significantly when pulled at bends in tortuous vessels, the segmented configuration of the thrombectomy device allows the thrombus capturers to operate independently of each other. Therefore, stretching one thrombus capturer does not cause the others to stretch significantly. As a result, when the thrombectomy device is retracted around the bend, the thrombus catcher at the bend may stretch and lose contact with the vessel wall, but the thrombus hemostatic material distal to and proximal to the bend will not stretch and will maintain contact with the vessel wall. Therefore, even if the thrombus catcher at the bend loses engagement with the thrombus, the thrombus will move to other thrombus catchers in contact with the vessel wall, be captured, and held.

[0041] In one embodiment, the thrombus trap of the thrombectomy device is eccentrically supported on a support wire. When the thrombus trap is deployed into a blood vessel and positioned concentrically within that vessel, the support wire is pushed out from the center, thereby offset from the central axis of the blood vessel and extending through the expansion frame of the thrombus trap. This eccentric arrangement of the expansion frame and the offset of the support wire from the central axis make it easier for the thrombus to pass through the expansion frame and be captured by it. The unit stent body of existing stent retriever devices may not allow thrombus capture (instead, it allows the thrombus to roll between the stent body and the vessel wall while the device is being retracted). In contrast, the segmented thrombus catchers of the thrombectomy device according to this embodiment allow the thrombus to enter the gaps between the thrombus catchers and, as a result, be captured by the thrombus catchers.

[0042] In one embodiment, the thrombus capturer of the thrombectomy device is attached to a support wire by a joint that is highly visible under fluoroscopy. For example, each joint connecting the thrombus capturer to the support wire may include a radiopaque marker. Such a radiopaque marker indicates a specific position along the support wire relative to the thrombus capturer. Thus, the radiopaque marker improves the visibility of the thrombectomy device and provides the operator of the thrombectomy device with clues to understand where the thrombus is located relative to the thrombus capturer.

[0043] Figure 1 shows a plan view of a thrombectomy device according to an embodiment of this device. The thrombectomy device 100 is an intravascular tool that can be used to treat acute ischemic stroke. The thrombectomy device 100 includes a proximal working area 102 that the operator uses to advance, retract, and rotate the distal working area 104 of the device. More specifically, the thrombectomy device 100 includes a support wire 106 for the operator to push to advance the distal working area 104, pull to retract the distal working area 104, or twist to rotate the distal working area 104. The thrombectomy device 100 also includes a plurality of thrombus capturers 108 that can be advanced through a microcatheter and deployed from the microcatheter into a target anatomical structure. Once deployed into the target anatomical structure, the thrombus capturers 108 can capture, take in, engage with, or mechanically integrate with the thrombus. The thus captured thrombus is recovered from the patient by pulling a support wire 106 to retract the thrombus capturers 108 and the thrombus from the vascular system.

[0044] In one embodiment, the support wire 106 includes a proximal wire end 110 and a distal wire end 112, and extends longitudinally along the wire axis from the proximal wire end 110 to the distal wire end 112. The support wire 106 may be a flexible, elongated wire formed from an elastic material such as stainless steel or a superelastic nickel-titanium alloy. Thus, the wire axis of the support wire 106 may 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 shorter than the total length of the thrombectomy device 100. For example, the distal wire end 112 may be located distal to at least one of the thrombus capture devices 108 and proximal to at least one distal end of the thrombus capture device 108. Thus, the distance from the proximal wire end 110 (proximal device end 114) to the distal wire end 112 may be shorter than the distance from the proximal wire end 110 to the distal device end 116.

[0045] Figure 2 shows a plan view of the distal portion of a thrombectomy device having a plurality of thrombus traps according to an embodiment. These thrombus traps are independently attached to a support wire 106. More specifically, each thrombus trap 108 includes its own extension frame, and each extension frame of the thrombus trap 108 is connected to the support wire 106 at its respective position. For example, the first thrombus capturer 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 position 209 along the support wire 106. The second thrombus capturer 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 position 217 along the support wire 106. The thrombectomy device 100 may have more than two thrombus capturers 108. For example, a third thrombus capturer 218 has a third expansion frame 220 and a third stem 222 connecting the third expansion frame 220 to a support wire 106 at a third joint 224. The third joint 224 is located at a third position 225 along the support wire 106. The mounting positions of each thrombus capturer 108 can be spaced apart longitudinally along the support wire 106. For example, the first position 209, the second position 217, and the third position 225 are at different longitudinal positions on the support wire 106. This allows the thrombus capturer 108 to have expansion frames arranged in series longitudinally, and each expansion frame to be supported independently on the support wire 106 relative to the other expansion frames.

[0046] The sequentially arranged thrombus capturers 108 can have the same or different structures. For example, in the embodiment shown in Figure 2, the most proximal thrombus capturer, i.e., the first thrombus capturer 202, and the intermediate thrombus capturer, i.e., the second thrombus capturer 210, are identical in that the stems and joints of their extension frames have the same shape. In contrast, the most distal thrombus capturer 108, i.e., the third thrombus capturer 218, may have a different shape from the first thrombus capturer 202 and the second thrombus capturer 210. Some of these morphological differences are described below. One difference is the presence of one or more struts 230 extending distally from the extension frame to support the filter 232 at the distal device end 116. Thus, independently supported thrombus trappers 108 can be sized and shaped to provide engagement with each thrombus, thrombus capture, flexibility, or any other performance attributes.

[0047] Figure 3 shows a perspective view of the distal portion of a thrombectomy device having multiple thrombus capture devices according to an embodiment. The support wire 106 supporting the thrombus trapper 108 has a proximal segment 302 and a distal segment 304. The proximal segment 302 is proximal to the thrombus trapper 108 and extends over the proximal working area 102, while the distal segment 304 extends through one or more of the thrombus trapper 108 into the distal working area 104.

[0048] Each segment of the support wire 106 can be adapted to its purpose. For example, the proximal segment 302 may primarily function to transmit axial and rotational loads from the operator to the distal working area 104. Thus, the proximal segment 302 of the support wire 106 can have a proximal diameter 306 suitable for its function. As an 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 primarily function as a support for the thrombus capturer 108 rather than primarily functioning to transmit the working force. For this purpose, the distal segment 304 may have a distal diameter 308 smaller than the proximal diameter 306. For example, the distal diameter 308 can be set to 0.004 inches to 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 small diameter of the distal segment 304 is also beneficial for other purposes. Firstly, the smaller diameter allows the distal segment 304 of the support wire 106 to be flexible, enabling it to undulate and spirally along the target anatomical structure and the internal dimensions of the thrombus capturer 108, as will be described later. Secondly, since the distal segment 304 extends through the thrombus capturer 108, the smaller diameter allows for a smaller packing ratio when advancing the thrombectomy device 100 through the microcatheter. A smaller packing ratio makes it easier to deliver the device through the microcatheter to the target anatomical structure.

[0049] The structure of the support wire 106 described above can be realized by a single wire. For example, the proximal segment 302 and the distal segment 304 can be formed by grinding a single wire at a discontinuous position between the proximal wire end 110 and the distal wire end 112, or by tapering the wire in any other way. As an example, a single wire may be 0.018 inches at the proximal wire end 110, tapering distally along its length, and having diameters of 0.010 inches, 0.006 inches, and 0.0045 inches at different positions along the wire length. The taper may be uniform or introduced at discontinuous positions to form multiple wire segments, each with a different diameter.

[0050] In one embodiment, the support wire 106 is formed by joining a plurality of wire segments. For example, the proximal segment 302 may be a first wire having its distal end at the first position 209. Similarly, the support wire 106 may include a second wire having its proximal end at the first position 209. The first wire may have a larger diameter than the second wire, as described above. Such wire segments can be joined by joints. For example, the first joint 208 that attaches the first thrombus capturer 202 to the support wire 106 can also connect the ends of multiple wire segments to form a single support wire 106.

[0051] Each joint of the thrombectomy device 100 can be formed using mechanical means, thermal means, or adhesive means. For example, the first joint 208 may include a marker band that is mechanically crimped around the support wire 106 and the first stem 206 of the first thrombus capturer 202 to attach the thrombus capturer to the support wire 106. The marker band may 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 may include a tail portion positioned adjacent to the support wire 106 and inside the marker band. When the marker band is crimped, the support wire 106 and the stem can be crimped together to secure the first thrombus capturer 202 to the support wire 106. In one embodiment, the marker band, the thrombus capturer, and the support wire 106 may be fixed to each other with adhesive to form the first joint 208.

[0052] The aforementioned joints may be formed by other means. For example, any joint between the thrombus capturer and the support wire 106 can be formed using laser welding, soldering, or brazing. Joints by mechanical, thermal, or adhesive means can fix the radiopaque marker 310 to the support wire 106 while providing adequate radiopaqueness. For example, a tungsten rod may be bonded to the support wire 106 at a first position 209. Such a thrombectomy device 100 includes a radiopaque marker at a joint along the support wire 106.

[0053] The radiopaque markers facilitate the visualization of the thrombectomy device under fluoroscopy. The locations of the aforementioned joints and radiopaque markers 310 can be used as clues for the operator to understand the relative placement of the thrombus capturer and the thrombus within the target anatomical structure. For example, if the radiopaque marker 310 of the first joint 208 is located proximal to the first expansion frame 204, the operator can retract the thrombectomy device 100 to retract the first joint 208 so that it passes over the thrombus and 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 position 217 along the support wire 106. This allows the operator to retract the thrombectomy device 100 to retract the second joint 216 so that it passes over the thrombus and enters the second expansion frame 212. Similarly, another radiopaque marker 310 can be placed at the third joint 224 at a third position 225 along the support wire 106. This allows the operator to retract the thrombectomy device 100 to retract the third joint 224 so that it passes over the thrombus and the thrombus enters the third expansion frame 220.

[0054] By positioning the radiopaque marker 310 closer to the interior of each of the aforementioned extension frames, various advantages can be obtained. Firstly, as mentioned above, these locations provide the operator with clear feedback on the relative position between the marker, the longitudinally aligned thrombi, and the interior of each expansion frame. Secondly, by positioning the marker band proximal to the expansion frame rather than at the same longitudinal position as the expansion frame, the expansion frame can contract to a non-expanded state distal to the radiopaque marker 310 without surrounding the marker. More specifically, the radiopaque marker 310 does not contribute to the contraction diameter of the expansion frame because its joint is proximal to the expansion frame. In other words, the joint does not increase the contraction diameter. As a result, this relative positional relationship between the marker and the expansion frame is favorable for the thrombectomy device 100's puncturing ratio (smaller contour in the non-expanded state) and contributes to improved delivery of the thrombectomy device via the microcatheter.

[0055] Figure 4 shows an end view of a plurality of thrombus traps deployed in free space according to an embodiment. Each thrombus capturer 108 is independently attached to a support wire 106 and has an extension frame that is eccentrically supported by this support wire. The support wire 106 includes a wire axis 402 that extends longitudinally through the wire body. As previously mentioned, since the support wire 106 is flexible, the wire axis 402 can have straight segments and curved segments. However, for modeling purposes, the wire axis 402 may be shown as linear (Figure 3) and represented as a single point in the end view of Figure 4.

[0056] Each thrombus capturer 108 has a capturer axis 404 that is radially offset from the wire axis 402. As described below, the thrombus capturer 108 can be formed by laser cutting a three-dimensional expandable structure from a cylindrical tube, thereby allowing the expandable frame of the thrombus capturer 108 to have a circular cross-sectional shape (contour), as shown in Figure 4. The centers of these cross-sectional shapes define each capturer axis 404 that extends longitudinally through the thrombus capturer 108. Because the capturer axes 404 are radially spaced from the wire axis 402, the thrombus capturer 108 is eccentrically supported on the support wire 106. More specifically, the stem of the thrombus capturer 108 is attached to the support wire 106 at the wire axis 402, but the extension frame of the thrombus capturer 108 is eccentrically supported relative to the support wire 106.

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

[0058] The radial planes of the thrombus capturers 108 may be uniformly or non-uniformly distributed around the support wire 106. In the embodiment shown in Figure 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 approximately 60°, the angle between the second radial plane 410 and the third radial plane 414 in the counterclockwise direction is approximately 60°, and the angle between the third radial plane 414 and the first radial plane 406 in the counterclockwise direction is approximately 240°. In other words, the angles between circumferentially adjacent thrombus capturers 108 are not equal, and the thrombus capturers 108 are not uniformly oriented with respect to the support wire 106. In contrast, radial planes can be uniformly distributed if the angles between all circumferentially adjacent thrombus traps 108 are equal. In a typical case, the angle between radial planes is 360° divided by the number of thrombus traps 108. For example, if there are three thrombus traps 108, and the angles between the first, second, and third planes are 120°, the expansion frames will be uniformly distributed around the support wire 106. In other words, the non-uniform distribution is illustrative, and it can be seen that radial planes can be uniformly distributed around the support wire 106 if the angles between radial planes are equal.

[0059] Figure 5 shows an end view of a plurality of thrombus traps deployed within a blood vessel according to an embodiment. As mentioned above, Figure 4 illustrates the eccentrically supported expansion frame. This Figure 4 shows a state in which the capture axis of the thrombus capturer 108 does not coincide when the distal working area 104 is naturally expanded in free space, for example, in a space where no external force is applied to the expansion frame. In contrast, Figure 5 shows the action of a thrombus capturer 108, which is independently and eccentrically supported, when it is deployed in a blood vessel 502.

[0060] When the non-concentrically supported expansion frame is constrained by the vessel wall 504 of the vessel 502, the vessel wall 504 presses the expansion frame radially inward, moving the thrombus trapper 108 toward concentric support. More specifically, considering 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 bends toward a concentric arrangement of the eccentrically supported expansion frame. However, in the illustrated example, the expansion frame is not perfectly concentric. This can actually be the case because the elasticity of the support wire 106 acts individually on each thrombus trapper 108 as a result of the independently supported structure, pressing the thrombus trapper 108 in different directions relative to the wire axis 402. Thus, when multiple thrombus trappers 108 are deployed within the blood vessel 502, as highlighted in Figure 5, the expansion frame is pressed against the blood vessel wall 504 in different oblique directions, as indicated by the force vector 506.

[0061] It is important to note that the cross-sections of the first thrombus capturer 202, the second thrombus capturer 210, and the third thrombus capturer 218 shown in Figure 5 are actually superimposed at different positions in the longitudinal direction. Therefore, the cross-sections of the support wire 106 shown in Figure 5 are at different longitudinal positions from each other. This understanding indicates that by deploying the thrombus capturer 108 into an occluded space such as a blood vessel 502, the support wire 106 is forced to be biased into a non-linear shape that is not located at the center (central axis) of the space. More specifically, when the thrombus capturer 108 is deployed into the blood vessel 502 with its expansion frame in contact with the blood vessel wall 504, the support wire 106 extends through one or more expansion frames at a position offset from the central axis 510 of the blood vessel 502. The effects of this independently eccentrically supported configuration of the thrombus capturer 108 will be further explained below.

[0062] Figure 6 shows a side view of a plurality of thrombus capturers deployed in free space according to an embodiment. As previously mentioned, each thrombus capturer 108 includes a stem 602 that connects each expansion frame 604 to a support wire 106 by its respective joint 606. The stems 602, expansion frames 604, and joints 606 can be individually labeled, for example, as first, second, and third, as previously mentioned, but in Figures 6 and 7, these characteristic symbols are uniformly labeled to generalize these features. In a natural state without any load (external force), the support wire 106 may extend through one or more of the extension frames 604 and be arranged linearly (straight). For example, the support wire 106 completely passes through the proximal and intermediate extension frames 604 in Figure 6 and terminates at the proximal end of the distal extension frame 604. The joints 606 are spaced longitudinally along the support wire 106, and the stems 602 are separated from each other. This allows the extension frame 604 to be supported independently by the support wire 106. Furthermore, the extension frame 604 is eccentrically supported by the support wire 106. This is evident from the fact that the capture shaft 404 is radially offset (vertically offset in the side view) from the wire shaft 402.

[0063] Figure 7 shows a side view of a plurality of thrombus traps deployed within a linear (straight-shaped) blood vessel according to the embodiment. When the distal operating area 104 is deployed within the blood vessel 502, the blood vessel wall 504 applies a deformation load 702 to the thrombus capturer 108. In this case, the deformation load 702 is a radial load, which moves the capturer axis to align radially. The deformation load 702 may also be an axial load (Figure 13) that causes stretching of one or more extension frames 604. In any case, as a result of the thrombus capturer 108 being independently supported by longitudinally spaced joints 606, the deformation load 702 applied to one extension frame 604 is not transmitted to the other extension frames 604. Rather, the extension frames 604 flex independently of each other. In Figure 7, it is shown that, in this regard, the proximal and distal extension frames 604 move downward, while the intermediate extension frame 604 moves upward. This independent movement of the extension frames 604 causes the capturer axis 404 to align linearly.

[0064] As the expansion frame 604 aligns within the blood vessel, the support wire 106 bends into a non-linear shape. More specifically, the proximal segment 302 of the support wire 106 may remain linear, for example, straight, but given that the capture axis 404 is positioned eccentrically with respect to the wire axis 402, as the capture axis 404 moves closer to the center, for example, to coincide with the central axis 510 of the blood vessel 502, the distal segment 304 of the support wire 106 supporting the expansion frame 604 may take on a non-linear, for example, curved shape. More specifically, the wire axis 402 is pressed in a direction away from the center (central axis) (e.g., radially outward toward the blood vessel wall 504), and consequently the support wire 106 may take on a curved shape different from the linear shape of the proximal segment 302.

[0065] In one embodiment, the support wire 106 extends along the inner wall of each expansion frame 604 through each thrombus capturer 108. For example, as shown in Figure 5, the support wire 106 within each expansion frame 604 is positioned along the inner wall of the expansion frame 604 and is circumferentially offset from the position where the primary force vector 506 acts on the vessel wall 504. The support wire 106 can extend in a wavy manner along the vessel wall 504. In the side view of Figure 7, this is illustrated by a path that curves vertically in the longitudinal direction of the support wire 106. Such a wavy path has peaks and valleys where the support wire 106 is pressed against the vessel wall 504 by the deformation load 702. These peaks and valleys may coincide with internal channels of the expansion frame 604, and for example, 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 pressed against the inner wall of the expansion frame 604 when biased away from the central axis 510 of the vessel 502.

[0066] Tertiarily, the undulating path of the support wire 106 may become a spiral path. More specifically, when the thrombus capturers 108 are arranged non-concentrically around the wire axis 402, the deformation load 702 causes the expansion frames 604 to move independently in different directions, aligning them with each other and biasing them to align with the vascular lumen. The connections to the support wire 106, for example, each joint 606, are also biased in different directions. As a result, the support wire 106 at one joint 606 may be biased to the vascular 502 at a first radial position, for example, at 0 degrees; at another joint 606, at a second radial position, for example, at 120 degrees; and at yet another joint 606, at a third radial position, for example, at 240 degrees. Furthermore, as the support wire 106 extends longitudinally through each of these radial joints 606, it can take on a helical structure. Specifically, the support wire 106 can spiral along the vessel wall 504 when the expansion frame 604 and each joint 606 are in contact with the vessel wall 504. In this way, the support wire 106 can undulate distally while in contact with the vessel wall 504 at one or more peaks or valleys, and can also spiral distally while continuously in contact with the vessel wall 504 along the length of the distal segment 304 of the support wire 106.

[0067] The wavy or spiral support wire 106 offers several performance advantages. Firstly, the offset of the support wire 106 from the vessel wall 504 causes each expansion frame 604 to be pressed against the vessel with force vectors 506 in different directions. The support wire 106 generates a reaction load to the deformation load 702 applied from the vessel wall 504 to the expansion frame 604, and this reaction load acts on the vessel wall 504 as a force vector 506. When the thrombus trapper 108 is deployed into the blood vessel 502, the support wire 106 is biased in different directions so as to move away from the central axis 510 of the blood vessel 502. Consequently, its reaction load is directed in the opposite direction to these biasing forces. Therefore, a force vector 506 acts on the expansion frame 604, causing the support wire 106 to press against the blood vessel wall 504, thus allowing the expansion frame 604 to exert a high radial force on the blood vessel wall 504 when deployed into the blood vessel.

[0068] A second advantage of the undulating or spiral support wire 106 is the effective clearance (gap) for trapping thrombi. When the thrombus capturer 108 is deployed into the blood vessel 502, the support wire 106 is offset to the periphery of the expansion frame 604 and the blood vessel 502, thereby keeping the central lumen, for example, the internal channel of the expansion frame 604, completely open to the passage of the thrombus. Referring further to Figure 7, when the expansion frame 604 is expanded and contacts the vessel wall 504, the support wire 106 runs along the vessel wall 504 at different circumferential positions on each expansion frame 604. A gap 704 exists between adjacent expansion frames 604, and this gap can become an opening from which a thrombus can enter the central lumen of the thrombectomy device 100. This central lumen can provide a volume of space formed radially inward from the inner walls of the vessel wall 504 and the expansion frame 604. A centrally located support wire 106 (e.g., a support wire 106 that coincides with the central axis 510 of the vessel 502) may prevent a thrombus from entering the central lumen and may deflect the thrombus radially outward. A thrombus that has deflected outward may then roll between the outer surface of the dilation frame 604 and the vessel wall 504 and may not be captured. In contrast, the circumferentially offset support wire 106 maximizes the volume of the central lumen that can receive the thrombus without obstructing it. The thrombus can then move completely into the central lumen so that it is captured by the expansion frame 604 in the process of being pulled through the vessel 502, rather than deviating outward.

[0069] In addition to using a circumferentially offset support wire 106 to open the central lumen of the device that accepts thrombi, the thrombus capture performance can also be improved by adjusting the gap 704 between the expansion frames 604. 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 drawing thrombi into the central lumen of the device. The gap 704 can be set to a size that ensures a thrombus, such as a hard thrombus rolling between the expansion frame 604 and the vessel wall 504, enters the gap 704 when it is 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 around 15 mm, to accommodate most hard thrombi, but it can of course be set to a different distance longitudinally depending on the range of thrombus sizes to be captured.

[0070] In one embodiment, the gap 704 between a pair of extension frames 604 may differ in size or shape from the gap 704 between other pairs of extension frames 604. For example, the length of the gap 704 between the most proximal and intermediate extension frames 604 in Figure 7 may differ from the length of the gap 704 between the intermediate extension frame 604 and the most distal extension frame 604 in Figure 7 (e.g., it can be shorter than the length of the gap 704 in Figure 7). Similarly, the structure of the extension frame 604 can have different shapes, such that the gap 704 between the most proximal extension frame 604 and the intermediate extension frame 604 in Figure 7 has a different shape from the gap 704 between the intermediate extension frame 604 and the most distal extension frame 604 in Figure 7. Variations in the length and / or shape of such gaps can provide openings that can adapt to accommodating more or less different thrombus types. For example, a shorter and wider proximal opening may be suitable for capturing hard thrombi, while a longer and narrower distal opening may be suitable for capturing soft thrombi.

[0071] Figure 8 shows a perspective view of a thrombus capture device according to one embodiment. As described above, each thrombus capturer 108 has components as an expansion frame 604 and a stem 602. The expansion frame 604 includes a distal frame end 706 and a proximal frame end 708. These frame ends define the openings of the expansion frame 604 to the internal channel 812, for example, a proximal opening into the cylindrical interior of the expansion frame 604 and a distal opening into the cylindrical interior. The expansion frame 604 may include at least one frame cell ring 802. The frame cell ring 802 may be configured to expand and contract. Geometrically, the expansion frame 604 may resemble a stent. For example, the frame cell ring 802 may be formed into a cylindrical expandable structure having two or more cells connected to each other in the circumferential direction and having an “open” or “closed” cell pattern. Such a cell pattern includes one or more slots, struts, or links 820 to form an expandable structure having proximal and / or distal openings for trapping thrombi. Similar to stents, the thrombus trapper 108 can be formed by laser cutting the cell pattern from a metal tube. As an example, the expansion frame 604 may be a self-expanding structure formed from a shape memory alloy, such as a nickel-titanium tube. However, unlike stents, the radial force of the expansion frame 604 is required to act to maintain a secondary structural shape that should accommodate thrombus trapping rather than to act as a support for opening atherosclerotic lesions.

[0072] Furthermore, unlike the stent support, the thrombus capturer 108 may include a stem 602 extending proximal to the expansion frame 604. More specifically, the stem 602 may extend proximal to the proximal stem end 804 from the proximal ring end 803 (proximal frame end 708) of the frame cell ring 802. The proximal stem end 804 may define the proximal position of the thrombus capturer 108, just as the distal frame end 706 may define the distal position or distal end of the thrombus capturer 108. Neither the distal nor proximal end of the thrombus capturer 108 is directly connected to an adjacent thrombus capturer. In other words, the thrombus capturer 108 is an independent unit freely suspended from the support wire 106.

[0073] In one embodiment, the stem 602 includes one or more branched 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 proximal from the expansion 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 branched 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 branched branches can act like tails, pulling the expansion frame 604 while connecting the frame cell ring 802 to the support wire 106. The shape of these branched branches can transmit forces (e.g., tensile forces) to the expansion frame 604 during operation, contributing to the capture of thrombi.

[0074] The aforementioned branching can have a structure that branches one or more times between the proximal stem end 804 and the proximal frame end 708 to transmit tensile force, and connects to each of the proximal ring ends 803. More specifically, the stem 602 can extend proximal from each proximal apex of the expandable ring structure. This ensures that the tensile force transmitted from the support wire 106 to the expandable frame 604 via the branching of each stem is uniformly distributed around the proximal frame end 708. Such uniform distribution of tensile force can reduce the tilt of the expandable frame 604 during device retrieval, and thus can reduce vascular damage and / or thrombus loss.

[0075] Some of the branching branches of the stem 602 may define passages 810 to internal channels 812 of the extension frame 604. For example, a pair of branching branches may diverge near the proximal stem end 804 and extend distally toward the proximal ring end 803. These pair of branching branches continue along the proximal end of the frame cell ring 802 at the proximal ring end 803 and converge to a link 820 between two adjacent frame cells. Thus, the branching and converging branches can form an “eye”-shaped passage 810 that provides a proximal opening to the internal channel 812. More specifically, a closed negative space between two arcuate branches can provide the passage 810. Similarly, other passages can be defined between the branches of the stem 602 on the opposite side of the capturer structure. These other passages are separated from the illustrated passage 810 by the branches but may open into the same internal channel 812. Thus, the passages of the thrombus capturer 108 provide ports from which a thrombus can enter and be captured in the expansion frame 604.

[0076] Figure 9 shows a side view of the thrombus capture device according to the embodiment. In this side view, the boundary between the expansion frame 604 distal to the proximal ring end 803 and the stem 602 proximal to the proximal ring end 803 can be seen. The internal channel 812 provides volume within the expansion frame 604. The stem 602 extends proximal from the expansion frame 604 to a joint 606 at the proximal stem end 804, which connects the thrombus trapper 108 to a support wire 106. The branches of the stem 602 can branch out to connect to different proximal ring ends 803. The branches of the stem 602 also form a passage 810, which has a passage plane 902 as shown in the side view of Figure 9. The passage plane 902 is a plane that contains a closed negative space between the branches defining the passage 810, as described above. In one embodiment, the mouth plane 902 extends obliquely with respect to the support wire 106. For example, while the support wire 106 includes a wire axis extending in the longitudinal direction, the mouth plane 902 may be positioned obliquely with respect to the wire axis, neither parallel nor perpendicular.

[0077] The angle of the opening plane 902 relative to the wire axis 402 (e.g., the oblique angle mentioned above) can facilitate the capture of thrombi. For example, by angling the opening plane 902, a lateral opening can be provided through which thrombi can pass more easily. Such oblique angles are one factor that influences the size of the gap 704 (see Figure 7) between adjacent extension frames 604. As mentioned above, the size of the gap 704 can affect the type of thrombus captured and how easily the thrombus is captured. For example, the angled opening plane 902 can provide an introduction of sufficient size for a rigid thrombus to roll more easily into the internal channel 812.

[0078] Figure 10 shows a perspective view of a thrombus capture device according to an embodiment. As mentioned above, the thrombus capturer 108 in the thrombectomy device 100 can have various shapes. In one embodiment, one or more of the extension frames 604 include a plurality of struts 230 extending distal to the frame cell ring 802. The strut 230 can extend distally from the distal end of the frame cell ring 802. For example, the strut 230 can extend from the peaks 1004 or valleys 1006 of the cell pattern at the distal end. The strut 230 may branch at the distal frame end 706 to extend to multiple ends, as shown in the figure. Alternatively, the strut 230 may be a single segment, for example, a linear columnar projection having a single proximal end at the frame cell ring 802 and a single distal end at the distal frame end 706.

[0079] Figure 11 shows a perspective view of a filter to be attached to a thrombus capture device according to an embodiment. The thrombectomy device 100 may include a filter 232 for capturing thrombi passing distal to 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 extending distally from the frame cell ring 802. The filter 232 may have a shape that converges distally. More specifically, the filter 232 may extend distally from the proximal filter end 1102 to the distal filter end 1104, and the proximal filter end 1102 may have a larger transverse dimension than the distal filter end 1104. The convergent shape of the filter 232 may form a closure structure for capturing a thrombus or portion of a thrombus that crosses the lumen of the blood vessel 502 and passes distal to the expansion frame 604.

[0080] In one embodiment, the filter 232 includes a web or mesh structure. For example, the filter 232 is formed from a polymer or metal filament that is woven in a web-like manner or woven into a mesh-like manner having a structure that converges distally, such as a cone. The web or mesh structure of the filter 232 may have porosity (porosity) that allows blood to pass through while capturing thrombi or portions of thrombi flowing 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, but the filter 232 may instead 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 (pore density). For example, the filter 232 can be formed from a polymer film having one or more pores formed through the film to allow blood flow. Such a filter 232 can be freely suspended from 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 extension frame 604. In one embodiment, the strut 230 converges to a single point (see Figure 16). The freely suspended and / or internally supported filter 232 can contract and expand within the target anatomy during delivery of the device (thrombectomy device) to prevent distal migration of the thrombus.

[0082] The thrombus capture device 108 includes a coil tip 1108. The coil tip 1108 extends distally from the filter 232 and is formed to be flexible and non-traumatic to the vessel wall 504. Furthermore, the coil tip 1108 is radiopaque, which can improve the visibility of the distal end of the thrombus capturer 108. For example, the coil tip 1108 may be formed from stainless steel, platinum-iridium, or other radiopaque metal or material that is visible under fluoroscopy. In one embodiment, the coil tip 1108 is joined to the filter 232 and / or strut 230 of the extension frame 604 by a joint provided by mechanical, thermal, or adhesive means. Such a joint may employ, for example, an adhesive, which adheres the filter 232 to the coil tip 1108.

[0083] Although filter 232 is shown as part of the most distal thrombus capturer 108 (e.g., see Figure 2), it can be seen that any thrombus capturer 108 in the thrombectomy device 100 may include its respective filter 232. Furthermore, any of the thrombus capturers 108 (most proximal, intermediate, most distal, etc.) may have distal ends converging to their respective distal ends 1106. More specifically, any and all of the extension frames 604 may close their distal ends by employing cage-like or filter-like structures that capture thrombi moving distally. For any of the thrombus trapping structures described herein, the distal shape of each thrombus trapping may be the same as or different from that of other thrombus trapping structures.

[0084] Figure 12 shows a schematic diagram of a thrombectomy device deployed in a curved blood vessel according to an embodiment. This diagram visually illustrates the advantages of the eccentrically supported expansion frame 604 and the undulating support wire 106, as described above. When the thrombectomy device 100 is deployed into the blood vessel 502, each thrombus capturer 108 is attached to the support wire 106 by a stem extending from the joint 606, so that it has a different clocking (angle) with respect to the central axis 510 of the blood vessel 502. For example, in the illustrated embodiment, the thrombectomy device 100 has four thrombus capturers 108, and each joint 606 and stem has a clocking that is 90 degrees counterclockwise different from the adjacent stem. Specifically, the most proximal thrombus capturer 108 has its stem at a position of 0 degrees with respect to the central axis 510 (at the bottom of the vessel wall 504), the second thrombus capturer 210 adjacent to the most proximal thrombus capturer 108 has its stem at a position of 90 degrees (90° counterclockwise with respect to the central axis 510), the third thrombus capturer 218 adjacent to the second thrombus capturer 210 has its stem at a position of 180 degrees, and the most distal thrombus capturer 108 adjacent to the third thrombus capturer 218 has its stem at a position of 270 degrees. As previously mentioned, the distal segment 304 of the support wire 106 is connected to the thrombus trapper 108 by joint 606, so as to undulate or spiral along and / or around the central axis 510. More specifically, the support wire 106 is pressed against the vessel wall 504 at the positions of each joint, which are 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 the central lumen of the vessel 502 and the internal channel 812 of the expansion frame 604, allowing the thrombus to be captured to effectively move into the internal channel 812 through the gap 704 between the thrombus trappers 108 (see Figure 7).

[0085] Figure 13 is a schematic diagram showing how the thrombectomy device according to the embodiment is drawn into a bend in a tortuous blood vessel. As mentioned above, this diagram visually illustrates the advantages of the independently mounted thrombus capturer 108. The expansion frames 604 are connected to the support wires 106, but they are not directly connected to one another. Therefore, the independently supported thrombus trappers 108 have degrees of freedom relative to each other, so that local deformation of an individual expansion frame 604 occurs without overall deformation of one or more other expansion frames 604. In other words, deformation of one expansion frame 604 does not necessarily affect the other expansion frames 604.

[0086] In one embodiment, when the thrombectomy device 100 is deployed into a tortuous blood vessel 502, one or more thrombus capturers 108 may be drawn over the bends in the blood vessel. More specifically, the support wire 106 is retracted through the blood vessel 502 to retrieve the thrombus capturer 108 (and the thrombus captured by the thrombus capturer), and such retraction of the support wire 106 may cause a deformation load 702 to be applied to one of the expansion frames 604. As mentioned above, the deformation load 702 may have a radial component, but when the thrombus trapper is pulled beyond the bend, it may have an axial component that stretches the expansion frame 604 located at this bend. More specifically, as shown in Figure 13, the tension caused by the proximal load applied to the joint 606 of the deformed thrombus trapper 108 and the distal load applied by the resistance force against the vessel wall 504 can stretch the thrombus trapper 108. Such a deformable load 702 can increase the length of the stretched extension frame 604 and simultaneously decrease its diameter. As a result of the decrease in diameter, the extension frame 604 may lose contact with the vessel wall 504. However, since the other thrombus catchers 108 are independently attached to the support wire 106, they remain unstretched despite the stretching of the thrombus catcher 108 at the bend. Therefore, the other thrombus catchers 108 do not lose contact with the vessel wall 504. In other words, the deformation of the thrombus catcher 108 is localized (minimized) to the thrombus catcher 108 at the bend, while the vessels 502 proximal and distal to this bend are protected by the adjacent thrombus catchers 108. As a result, thrombi 1302 pushed out from the extended thrombus capturer 108, or thrombi 1302 that detach in the vascular lumen and flow downstream, can be captured by adjacent thrombus capturers 108. Therefore, such independently mounted thrombus capturers 108 make it possible to efficiently capture the entire thrombus 1302 and efficiently recover the thrombus from the target anatomical structure.

[0087] Figure 14 shows a flowchart of the manufacturing method of the thrombectomy device according to the embodiment. The methods described herein are provided as examples, and those skilled in the art may carry out such methods by performing alternative and / or additional manufacturing steps to provide the aforementioned thrombectomy device 100.

[0088] In step 1402, the support wire 106 is formed. In one embodiment, the support 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 position 209. As previously mentioned, the support wire 106 may 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 may have a smaller diameter than the proximal segment 302. Thus, the support wire 106 may have a rigidity shape that decreases distally.

[0089] In one embodiment, instead of grinding the support wire 106 (or in addition to grinding), the support wire 106 can be formed from a plurality of wire segments joined at individual positions. The wire segments can be joined using joints 606 by mechanical, thermal, or adhesive means. The distal wire segments may have a smaller diameter than the proximal wire segments to provide a rigid shape that decreases distally.

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

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

[0092] In step 1408, radiopaque markers 310 are attached to the first position 209 and / or second position 217 of the support wire 106. The radiopaque markers 310 can be mechanically coupled to the stem 602 of the extension frame 604 and the support wire 106. For example, the radiopaque markers 310 can be marker bands that are crimped around the stem 602 and the support wire 106. Alternatively, the radiopaque markers 310 can be radiopaque particles, ink, or other structures that are bonded to the support wire 106 with an adhesive to provide the operator with feedback on the position of the joint 606.

[0093] Figure 15 shows a flowchart illustrating a method for removing a thrombus from a blood vessel using a thrombectomy device according to an embodiment. In step 1502, the thrombectomy device 100 is introduced into the blood vessel 502 containing the thrombus 1302. First, the guidewire passes through the blood vessel 502, traversing a target area within the narrowed vessel that is at least partially occluded by the thrombus 1302. The microcatheter can be tracked along the guidewire so that its distal end is positioned distal to the thrombus 1302. Once the microcatheter reaches the desired position, the guidewire is retracted and removed from the microcatheter. Next, the thrombectomy device 100 is advanced through the lumen of the microcatheter until its distal end 1106 is located near or distal to the distal end of the microcatheter. When the thrombectomy device 100 is introduced into the blood vessel 502, the microcatheter can hold the thrombus catcher 108 in a constrained state. That is, the lumen of the microcatheter has a smaller diameter than the thrombus catcher 108 in its expanded state, and therefore the expanded frame 604 can be introduced into the blood vessel 502 through the microcatheter in its unexpanded state.

[0094] In step 1504, the aforementioned multiple thrombus capture devices 108 are deployed. As the microcatheter is retracted and forward pressure is applied to the support wire 106 of the thrombectomy device 100, the thrombus capture devices 108 are deployed so that they come into contact with the vessel wall 504 of the vessel 502 from the distal end of the microcatheter. Specifically, the expansion frame 604 of the thrombus capture device 108 can move into an expanded state (Figure 1). In this expanded state, the expansion frame 604 adheres tightly to the vessel wall 504. Since the expansion frames 604 are eccentrically supported by the support wires 106, when the expansion frames 604 deform into a concentric arrangement within the blood vessel (Figure 12), each expansion frame 604 is pressed against the blood vessel wall 504 in a different transverse direction. When the non-concentrically supported expansion frames 604 are in an off-center arrangement, the support wires 106 are shifted away from the center and towards the blood vessel wall 504. Specifically, the support wires 106 extend through the blood vessel 502 in an offset state from the central axis 510 of the blood vessel 502.

[0095] After expanding the thrombus capture device 108, the thrombus removal device 100 should be left in place for several minutes so that the thrombus 1302 engages with the expansion frame 604. Next, in step 1506, the support wire 106 is pulled to retract the thrombectomy device 100, further engaging, capturing, or taking in the thrombus 1302 with the expansion frame 604. The support wire 106 is withdrawn until the thrombus capturer 108 and the captured thrombus 1302 are removed from the target vascular system.

[0096] Figure 16 shows a plan view of the distal portion of a thrombectomy device equipped with multiple thrombus capturers according to another embodiment. The distal operating region 104 of the thrombectomy device 100 has several features that are interchangeable with those of the previously described embodiment. Such features are not described again in order to simplify the explanation with respect to Figure 16.

[0097] In one embodiment, the distal operating region 104 includes a plurality of thrombus capturers 108 having longitudinally arranged 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 Figure 2, the thrombus capturers 108 are arranged so as not to overlap longitudinally, with each joint 606 of the thrombus capturer 108 located distal to the immediately proximal thrombus capturer 108. However, as shown in Figure 16, the thrombus capturers 108 can be arranged to overlap at least partially longitudinally. For example, the second thrombus capturer 210 is connected to the support wire 106 by a second stem 214 at a position 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 a second joint 216 located proximal to the first expansion frame 204.

[0098] The overlapping of the thrombus capturers 108 is facilitated by an elongated stem 602 that extends proximal from the more distal expansion frame 604(220) and connects to the support wire 106 at a position more proximal than the more proximal expansion frame 604(212). This elongated stem 602 can improve the flexibility and mobility of the expansion frame 604(212) relative to the support wire 106. In other words, although the expansion frame 604(212) is shown to be concentrically positioned along the support wire 106, it is hinged outward (radially) at the joint 606(216) and supported non-concentrically (and eccentrically) relative to the support wire 106 (see Figure 17).

[0099] Here, connecting the expansion frames 604 at a joint 606 located outside the internal channel 812 of the adjacent expansion frame 604 (see Figure 6) not only improves the elasticity and flexibility of the expansion frame 604 relative to the support wire 106, but also contributes to an optimal packing ratio for the thrombectomy device 100. As mentioned above, by positioning the joint 606 on the support wire 106, which is not located radially inward of the frame cell ring 802, the frame cell ring 802 can be contracted to a smaller size during delivery. In other words, by positioning the joint 606 proximal to the expansion frame 604(220), the delivery performance of the thrombectomy device can be improved.

[0100] Referring further to Figure 16, one or more of the thrombus traps 108 of the thrombectomy device 100 may have a closed distal end. For example, the third thrombus trap 218 (the most distal thrombus trap) includes several struts 230 projecting distally from the frame cell ring 802. The struts 230 can converge at their distal ends 1106 to form a closed cage-like structure. More specifically, the cage-like structure formed by the struts 230 has a funnel or conical shape that allows blood flow while providing some resistance to the distal flow of the thrombus 1302 (see Figure 13) through the blood vessel 502.

[0101] Figure 17 shows a schematic diagram of a thrombectomy device according to an embodiment, which includes a support wire having one or more bent portions. The undulating and / or spiral distal segments 304 (see Figure 3) of the support wire 106 may include one or more bends 1702. Each bend 1702 is caused by a change in the curvature of the support wire 106 along the distal wire axis 402. The bend 1702 may coincide with the position where the thrombus capturer 108 is attached to the support wire 106. For example, there is a undulation at the peak of the first position 209. The first position 209 is the position where the first thrombus capturer 202 is attached to the support wire 106 by the first joint 208. Similarly, there is a undulation at the second position 217, which is a trough immediately distal to this peak. The second position 217 is the position where the second thrombus capturer 210 is attached to the support wire 106 by the second joint 216.

[0102] The bend 1702 along the support wire 106 may be caused by the interaction between the thrombus capturer 108 and the vessel wall 504. For example, the helical path of the support wire 106 described above can pass through joint 606(208), and thus the bend 1702 is caused by the support wire 106 taking a specific shape to extend from one joint 606(208) to the other joint 216. Furthermore, the bend 1702 may also be caused by the direct action of the thrombus capturer 108 itself. For example, the thrombus capturer 108 may have a stem hole 1704 (see Figure 8) that passes near the stem 602 (e.g., the proximal stem end 804). The support wire 106 may be passed through the stem hole 1704 (Figure 8), in which case an angle may naturally occur between the stem 602 and the support wire 106 in the stem hole 1704. Furthermore, if the joint 606 is formed by crimping marker bands around the support wire 106 and stem 602, the joint 606 may generate a local bending moment in the support wire 106 at the stem hole 1704. When the support wire 106 bends due to this bending moment, a bend 1702 is created at the location of the joint 606. Thus, when deployed in free space or within a blood vessel 502, the thrombectomy device 100 may have a support wire 106 with a bent portion 1702 for each of the thrombus capturers 108 attached to the distal segment 304.

[0103] Figure 18 shows a plan view of the distal portion of a thrombectomy device having a plurality of thrombus capturers, according to an embodiment of the device, when deployed in free space. The thrombectomy device 100 includes a plurality of thrombus traps 108, each having an extension frame 604 (204, 212), attached to a support wire 106. 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. Since the thrombectomy device 100 is deployed in free space 1800 (e.g., not constrained by surrounding surfaces), the extension frames 604 (204, 212) of each thrombus trap 108 are non-concentric with each other.

[0104] In one embodiment, the second thrombus capturer 210 is the most distal thrombus capturer 1802. The most distal thrombus capturer 1802 has a second expansion frame 212, which may include a frame cell ring, as described above. As illustrated in Figure 11 above, the frame cell ring may support a filter (not shown) for capturing debris such as blood clots. Such a filter may be attached to the distal end of the distal end thrombus capturer 1802 and may include a mesh or web structure. Such a web structure has a higher surface area than the second expansion frame 212, allowing it to capture debris flowing downstream in the blood vessel 502.

[0105] One or more thrombus capturers 108 in the thrombectomy device 100 may have a segmented expansion frame 604(212). In one embodiment, the most distal thrombus capturer 1802 has a segmented (divided) body 1804. More specifically, the expansion frame is divided into a plurality of segments, and the segmented body 1804 has a proximal frame segment 1806 and a distal frame segment 1808. Each frame segment is connected by a hinge 1810 and can be separated from each other by gaps 1812 between segments at all positions other than the hinge 1810. The structure and function of such a segmented expansion frame 604(212) will be described further below.

[0106] Figure 19 shows a plan view of the distal portion of a thrombectomy device having a plurality of thrombus capturers according to an embodiment of the device, when deployed inside a blood vessel. When the thrombectomy device 100 is deployed into 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 Figure 19), the expansion frame 604 (204, 212) is biased (pressed) to be concentric with each other. Similar to the embodiment described above, when the thrombectomy device 100 is deployed into 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 curve 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 forced to be concentric in this way, the average amount of curvature 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 free space 1800.

[0107] In one embodiment, the thrombus trappers 108 are aligned concentrically with one another along the vessel wall 504. The extension frames 604(204,212) of the thrombus trappers 108 can be in close proximity to one another. More specifically, the distance between adjacent extension frames 604(204,212) (or between frame segments of the same extension frame 604(212)) can be minimized. As previously mentioned, the first thrombus capturer 202 has a distal frame end 706, and the second thrombus capturer 210 has a proximal frame end 708. These frame ends may be separated by a gap 704. The distal frame end 706 can be aligned with the proximal frame end 708 so as to minimize the gap 704. 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 opening at the proximal frame end 708 may be in the range of 1 to 10 mm (e.g., 1 to 5 mm).

[0108] The shape of the distal frame end 706 is the same as the contour of the proximal frame end 708, extends parallel to it, and / or can coincide with it. Here, the shapes of these frame ends are determined by the contour or shape of a virtual spline passing through the extended frame 604 (204, 212) at each end. For example, the shape of the distal frame end 706 can be determined by a virtual spline extending through the most distal point of each of the distal cells (e.g., cell tips) constituting the first thrombus capturer 202. Similarly, the shape of the proximal frame end 708 can be determined by a virtual spline extending through a strut defining the mouth of the second thrombus capturer 210. These shapes can closely coincide or coincide with each other, as indicated by their contours. More specifically, the first thrombus capturer 202 can be adjacent to the second thrombus capturer 210 without the thrombus capturers actually making contact. Therefore, each thrombus capturer 108 can coincide with or fit together with one another to approximate a continuous cylindrical body, even though gaps 704 may exist separating the segments of the body.

[0109] By positioning the thrombus capturer 108 and / or its segments in close proximity, the frame surface area capable of engaging with the thrombus along the vessel wall 504 can be maximized. However, as mentioned above, it is beneficial to ensure a pathway for the rigid thrombus to move from the vessel wall 504 toward the lumen of the thrombus capturer. In one embodiment, the struts constituting the cell at the distal frame end 706 of the first thrombus capturer 202 are designed to bend radially inward. More specifically, the frame cell has sufficient flexibility so that when a rigid thrombus is pressed against the distal frame end 706, the frame cell can be deformed radially inward. In other words, the distal end of the thrombus capturer 108 folds inward, allowing the rigid thrombus to pass through the lumen of the thrombus capturer 108. Therefore, by minimizing the axial distance between adjacent thrombus capturers 108 in this way, an overall structure is provided that allows hard thrombi to be captured within the thrombus capturer 108 while effectively capturing soft thrombi.

[0110] Figure 20 shows a perspective view of the most distal thrombus capture device of the thrombectomy device according to the embodiment. In the most distal thrombus capturer 1802, the segmented body 1804 may include frame segments that approach and match each other. For example, the proximal frame segment 1806 has a distal segment end 2002 that approaches and matches the proximal segment end 2004 of the distal frame segment 1808. The terminology and function of adjacent frame segments are substantially the same as those described above for adjacent thrombus trappers 108. More specifically, the distal segment end 2002 can be separated from the proximal segment end 2004 by a gap 1812 between segments, which is substantially the same as the gap 704 between the distal frame end 706 and the proximal frame end 708 described above. The gap 1812 between segments can separate the frame segments at all circumferential positions of the segmented body 1804, except for the position where the hinge 1810 connects the distal frame segment 1808 to the proximal frame segment 1806.

[0111] As is evident from the perspective view, the hinge 1810 is provided at the connection point between the tail portion 2008 of the distal frame segment 1808 and the frame cell ring at the distal end of the proximal frame segment 1806. The frame segments can be formed integrally (e.g., cut from a single metal tube), so 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] Figure 21 shows a side view of a plurality of thrombus traps deployed within a blood vessel according to an embodiment. When the thrombectomy device 100 is deployed into the blood vessel, the expansion frame 204 and frame segments 1806, 1808 can align concentrically with one another under inward pressure from the vessel wall 504 (see Figure 5). When no axial load is applied to the expansion frame 604 (204) via the support wire 106, the gaps 704 between adjacent thrombus traps 108 and the gaps 1812 between frame segments can be minimized. For example, adjacent contours of the expansion frame and frame segments can coincide with each other and be separated by gaps 704, 1812 between 1 and 10 mm (e.g., 1 and 5 mm). This allows the thrombus trap 108 to function as a continuous cylindrical structure that uniformly contacts the vessel wall 504 and locks in the thrombus.

[0113] Figure 22 shows another side view of a plurality of thrombus traps deployed within a blood vessel according to the embodiment. When a deformable load (e.g., an axial load to retract the support wire 106 and thrombus catcher 108 through the blood vessel 502) is applied to the support wire 106, this deformable load causes the frame segments of the segment body 1804 (see Figure 20) and / or the independent thrombus catchers 108 to tilt relative to each other. More specifically, the gaps 704 between adjacent thrombus catchers 108 and / or the segment gaps 1812 between adjacent frame segments will widen. Such tilting due to independently mounted structures and / or hinged structures can be caused by the flexibility of the joint along the support wire 106 and / or the hinges 1810 between the frame segments.

[0114] The axial load that retracts the aforementioned support wire 106 acts in a distributed manner throughout the frame structure, causing the frame and individual frame segments to oscillate outward from one another while maintaining their cylindrical shape, rather than stretching and reducing the diameter of each frame and frame segment. More specifically, these segments tilt, but their contours do not collapse. These constituent segments can expand outward to press against the thrombus within the blood vessel 502. Such tilting motion is particularly beneficial around bends in tortuous vessels. When the thrombectomy device 100 is deployed around a bend in a tortuous vessel, contact between the vessel wall 504 and each component segment can be maintained by limiting the axial extension of the aforementioned component segments. Thus, these component segments can maintain contact with the thrombus along the vessel wall 504 and engage the thrombus more effectively.

[0115] The tilting motion of the hinged frame segments, in addition to engaging the thrombus around the bend of the blood vessel, can provide an opening for the rigid thrombus to enter the lumen of the thrombus trapper 108. More specifically, the widening gaps between the constituent segments allow the rigid thrombus to pass through the lumen radially inward. Thus, in conjunction with the above explanation, the thrombectomy device 100 incorporates one or more thrombus capturers 108 having segmented bodies 1804, which allows each frame segment to be withdrawn (retracted) through the blood vessel 502 with minimal stretching, and also allows the frame segment to open in order to capture hard thrombi while pressing soft thrombi outward with the frame segment.

[0116] Referring again to Figure 20, as shown in this figure, multiple frame markers 2010 can be attached to one or more of the extension frames 604. The frame markers 2010 can improve the visibility of these attached extension frames 604. More specifically, the frame markers 2010 can provide the user with visual feedback under fluoroscopy, allowing them to confirm the location of the thrombus capturer 108 within the target anatomical structure. Such flame markers 2010 can be fabricated from radiopaque materials such as platinum-iridium. The flame markers 2010 may be positioned along the most distal flame cell ring 802 (see Figure 8) of the thrombectomy device 100. In one embodiment, the flame markers 2010 are attached to one or more of the distal end struts of each thrombus capturer 108 of the thrombectomy device 100.

[0117] Figure 23 shows a perspective view of a frame marker according to an embodiment. The frame marker 2010 can be formed by plating (electrodeposition) a radiopaque material onto the extension frame 604. Alternatively, the frame marker 2010 can be formed as a band (strip) that is pressed onto the extension frame 604. In one embodiment, the frame marker 2010 includes a marker coil 2300. The marker coil 2300 can be formed from a radiopaque wire that is coiled or wound around the struts of the extension frame 604. Such a wire is wound, for example, around the struts of the distal end thrombus catcher 1802 in 5 to 10 turns. Solder may be applied around the marker coil 2300 to secure the coil to the struts of the thrombus catcher 1802. Furthermore, as shown in the figure, bulbous shapes may be provided at both ends of the coil by solder to form a non-traumatic surface that does not damage the vessel wall 504 during use.

[0118] Figure 24 shows a plan view of a radiopaque coil attached to a support wire of a thrombectomy device according to an embodiment. The thrombectomy device 100 may include a frame marker 2010 (see Figure 20) on the most distal thrombus capturer 1802, as well as a radiopaque coil 2400 mounted on the proximal support wire 106 of the thrombus capturer 108. The radiopaque coil 2400 provides visual feedback to the user under fluoroscopy, helping to confirm the position of the proximal region of the thrombectomy device 100. As previously mentioned, the support wire 106 may include a distal segment 304 that supports the thrombus trapper 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 trapper 108, and the distal segment 304 extends through the thrombus trapper 108 (and at least one of the thrombus trappers 108 is mounted on the distal segment 304).

[0119] In one embodiment, the proximal segment 302 and the distal segment 304 are connected to a radiopaque coil 2400 (see Figure 24). For example, the proximal segment 302 may have a distal end connected to the radiopaque coil 2400 at a coil joint 2402. The distal segment 304 can also be connected to the radiopaque coil 2400 by a coil joint 2402. For example, the coil joint 2402 may be formed by soldering the radiopaque coil 2400, the proximal segment 302, and the distal segment 304 together. The distal segment 304 may extend distally through the radiopaque coil 2400. In one embodiment, a thrombus capturer 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 capturers 108 by a joint distal to the first joint 208.

[0120] The radiopaque coil 2400 enhances the visibility of the thrombectomy device 100 and strengthens the joint between the proximal segment 302 and the distal segment 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 to connect the radiopaque coil 2400 to the proximal segment 302 or the distal segment 304. The proximal segment 302 of such a support wire 106 may have a larger diameter than the distal segment 304 of the support wire 106, as described above.

[0121] The method of removing thrombi using the thrombectomy device 100 shown in Figures 18 to 24 can be carried out using the same or a similar procedure as the method described in Figure 15 above. Specifically, first, the thrombectomy device 100 is introduced into the blood vessel 502 containing the thrombus. In a free state, the thrombus catcher 108 may be displaced from each other in a non-concentric relationship in order to maintain its shape, but when the thrombus catcher 108 is deployed inside the blood vessel 502, the expansion frame 604 (204, 212) of the thrombus catcher 108 can be brought into contact with the blood vessel wall 504, and this blood vessel wall biases the expansion frame 604 (204, 212) to be concentric with each other due to its restraining force. Next, the thrombectomy device 100 is retracted, for example by pulling the support wire 106, in order to capture the thrombus in the extension frame 604 (204, 212). As the thrombectomy device 100 is retracted, the independent thrombus catchers and / or the frame segments of the segmented body 1804 can tilt relative to each other. With this tilting motion, the axial extension of the individual body is restricted, and each constituent segment presses the thrombus outward, opening a wide gap in the lumen of the thrombus catcher 108 to receive the rigid thrombus. As a result, this method of thrombus uptake makes it possible to provide an excellent thrombectomy device 100 that minimizes the stretching of the frame structure and effectively uptakes the thrombus.

[0122] below, At the time of application Embodiments are described in accordance with the claims. A thrombectomy device according to one embodiment is: Support wire and This includes a plurality of thrombus traps independently attached to this support wire, Each of the thrombus capture devices has an extension frame that is eccentrically supported by the support wire, When the plurality of thrombus traps are deployed into a blood vessel, the expansion frame comes into contact with the blood vessel wall, and the support wire is configured to extend through one or more of the expansion frames at a position offset from the central axis of the blood vessel.

[0123] In a thrombectomy device according to one embodiment, The extension frame is supported by the support wires in a non-concentric manner, When the multiple thrombus traps are deployed into the blood vessel, the expansion frames each press against the vessel wall in different transverse directions.

[0124] In a thrombectomy device according to one embodiment, When the expansion frame is in contact with the blood vessel wall, the support wire extends spirally along the blood vessel wall.

[0125] In a thrombectomy device according to one embodiment, Each of the thrombus capture devices includes a stem that connects the extension frame to the support wire with a joint, The joints are arranged longitudinally along the support wires at intervals so that the deformation load applied to one extension frame is not transmitted to the other extension frame.

[0126] In a thrombectomy device according to one embodiment, The deformation load is caused by retracting the support wire through the blood vessel, and The plurality of thrombus traps are each independently attached to the support wire such that, when one of the expansion frames is stretched or not in contact with the vessel wall due to the deformation load, the other expansion frames are not stretched or are in contact with the vessel wall.

[0127] In a thrombectomy device according to one embodiment, The aforementioned multiple thrombus trappers are, A first thrombus capture device having a first expansion frame and a first stem, A second thrombus capture device having a second expansion frame and a second stem, The second extension frame is distal to the first extension frame, and the second stem is coupled to the support wire at each joint proximal to the first extension frame.

[0128] In a thrombectomy device according to one embodiment, Furthermore, the joint is equipped with a radiopaque marker.

[0129] In a thrombectomy device according to one embodiment, Each of the thrombus capture devices has a radial plane that includes the capture device axis and the wire axis of the support wire, and these radial planes are angularly offset from each other with respect to the support wire.

[0130] In a thrombectomy device according to one embodiment, The radial plane is distributed evenly in terms of angles with respect to the support wire.

[0131] In a thrombectomy device according to one embodiment, Each of the extension frames includes a frame cell ring coupled to the stem.

[0132] In a thrombectomy device according to one embodiment, The stem includes a plurality of branched branches, which extend between the joint and the proximal ring end of the frame cell ring, forming an opening to the internal channel of the extension frame.

[0133] In a thrombectomy device according to one embodiment, The aforementioned passage opening has a surface that extends obliquely with respect to the support wire.

[0134] In a thrombectomy device according to one embodiment, One or more of the extension frames include a plurality of struts that extend distal to the frame cell ring and converge at the distal tip.

[0135] In a thrombectomy device according to one embodiment, Furthermore, it includes a filter coupled to the frame cell ring.

[0136] In a thrombectomy device according to one embodiment, The aforementioned support wire is A proximal segment located more proximal to the aforementioned multiple thrombus traps, A distal segment extending through one or more of the plurality of thrombus traps, The proximal segment is linear, and the distal segment is non-linear.

[0137] In a thrombectomy device according to one embodiment, The distal segment includes one or more bent portions.

[0138] In a thrombectomy device according to one embodiment, The one or more bent portions coincide with the positions where the plurality of thrombus capturers are attached to the support wire.

[0139] In a thrombectomy device according to one embodiment, The proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

[0140] A method according to one embodiment comprises the following steps a and b. a. A first thrombus capture device is attached to the support wire. Here, the first thrombus capture device includes a first expansion frame that is eccentrically supported on the support wire in a first position. b. A second thrombus capture device is attached to the support wire. Here, the second thrombus capture device includes a second expansion frame that is eccentrically supported on the support wire, and the first expansion frame and the second expansion frame are supported non-concentrically relative to the support wire.

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

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

[0143] One embodiment of a method for removing a thrombus from a blood vessel comprises the following steps a to c. a. A mechanical thrombectomy device is introduced into the blood vessel containing the thrombus. The thrombectomy device includes a support wire and a plurality of thrombus catchers independently attached to the support wire, each of which includes an expansion frame that is introduced into the blood vessel in an unexpanded state. b. The plurality of thrombus traps are deployed, and the expansion frame is moved to an expanded state in contact with the vessel wall of the vessel. Here, the expansion frame is supported eccentrically by the support wire such that when the expansion frame contacts the vessel wall, the support wire extends through the vessel offset from the central axis of the vessel. c. The thrombus removal device is retracted, and the thrombus is taken into the expansion frame.

[0144] In a method for removing a blood clot from a blood vessel according to one embodiment, The expansion frames are supported non-concentrically relative to the support wires such that when the plurality of thrombus traps are deployed, the expansion frames press against the vessel wall in different transverse directions.

[0145] A thrombectomy device according to one embodiment is: Support wire and This includes a plurality of thrombus traps, each independently attached to a support wire and having an extension frame, When the thrombectomy device is deployed in free space, the expansion frames are non-concentric with each other, whereas when the thrombectomy device is deployed inside a blood vessel and the expansion frames are in contact with the blood vessel wall, the expansion frames are biased to be concentric with each other.

[0146] In a thrombectomy device according to one embodiment, The plurality of thrombus capture devices include a first thrombus capture device proximal to the second thrombus capture device. The first thrombus capturer has a distal frame end, and the second thrombus capturer has a proximal frame end, and the distal frame end can be aligned to coincide with the proximal frame end.

[0147] In a thrombectomy device according to one embodiment, The gap between the distal frame end and the proximal frame end during the alignment is less than 10 mm.

[0148] In a thrombectomy device according to one embodiment, The most distal thrombus capture device includes a frame cell ring and a filter coupled to this frame cell ring.

[0149] In a thrombectomy device according to one embodiment, The aforementioned support wire is The 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 connected to a radiopaque coil attached to the support wire.

[0150] In a thrombectomy device according to one embodiment, The proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

[0151] In a thrombectomy device according to one embodiment, further, The extension frame comprises a plurality of frame markers attached to one or more of the extension frames, wherein the plurality of frame markers are radiopaque.

[0152] In a thrombectomy device according to one embodiment, When the thrombectomy device is deployed into the blood vessel and the expansion frame is brought into contact with the vessel wall, the support wire is biased to undulate along the vessel wall while being offset from the central axis of the blood vessel.

[0153] A thrombectomy device according to one embodiment is: Support wire and A first thrombus capture device, which is attached to the support wire and has a first expansion frame, A second thrombus capture device, which is attached to the support wire and has a second expansion frame, is provided, The second extension frame of the second thrombus capturer includes a segmented body having a proximal frame segment connected to a distal frame segment by a hinge, and moreover, When the thrombectomy device is deployed in free space, the first expansion frame and the second expansion frame are not concentric with each other, whereas when the thrombectomy device is deployed inside a blood vessel and the first expansion frame and the second expansion frame come into contact with the blood vessel wall, the first expansion frame and the second expansion frame are biased to be concentric with each other.

[0154] In a thrombectomy device according to one embodiment, The proximal frame segment has a distal segment end, and the distal frame segment has 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 solely by the hinge.

[0155] In a thrombectomy device according to one embodiment, When a deformation load is applied to the support wire to retract it through a blood vessel, the distal frame segment and the proximal frame segment of the segmented body tilt around the hinge due to the deformation load, thereby expanding the circumferential gap between these frame segments.

[0156] In a thrombectomy device according to one embodiment, The first thrombus capturer is located more proximal to the second thrombus capturer. The first thrombus capturer has a distal frame end, and the second thrombus capturer has a proximal frame end, and the distal frame end can be aligned to coincide with the proximal frame end.

[0157] In a thrombectomy device according to one embodiment, The gap between the distal frame end and the proximal frame end during the alignment is less than 10 mm.

[0158] In a thrombectomy device according to one embodiment, The second thrombus capture device includes a frame cell ring and further comprises a filter coupled to this frame cell ring.

[0159] In a thrombectomy device according to one embodiment, When the thrombectomy device is deployed into the blood vessel and the expansion frame is brought into contact with the vessel wall, the support wire is biased 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 comprises the following steps a to c. a. A mechanical thrombectomy device is introduced into the blood vessel containing the thrombus. The thrombectomy device includes a support wire and a plurality of thrombus catchers, each including an expansion frame, wherein the plurality of thrombus catchers are independently attached to the support wire, and the expansion frames are non-concentric with each other when the thrombectomy device is deployed in free space. b. The plurality of thrombus traps are deployed within the blood vessel, and the expansion frames are brought into contact with the blood vessel wall. At this point, the expansion frames are biased to be concentric with one another. c. The thrombus removal device is retracted, and the thrombus is taken into the expansion frame.

[0161] In a method for removing a thrombus from a blood vessel according to one embodiment, The plurality of thrombus capture devices include a first thrombus capture device proximal to the second thrombus capture device, the first thrombus capture device having a distal frame end, and the second thrombus capture device having a proximal frame end, and furthermore, the distal frame end can be aligned to coincide with the proximal frame end.

[0162] In a method for removing a thrombus from a blood vessel according to one embodiment, The most distal thrombus capturer includes a frame cell ring and further comprises a filter coupled to this frame cell ring.

[0163] In a method for removing a thrombus from a blood vessel according to one embodiment, The aforementioned multiple thrombus trappers are, A first thrombus capture device, which is attached to the support wire and has a first expansion frame, A second thrombus capture device, which is attached to the support wire and has a second expansion frame, is included, The second extension frame includes a segmented body having a proximal frame segment connected to a distal frame segment by a hinge.

[0164] In a method for removing a thrombus from a blood vessel according to one embodiment, When the thrombectomy device is deployed inside the blood vessel and the expansion frame is in contact with the blood vessel wall, the support wire is biased to undulate along the blood vessel wall of the blood vessel, offset from the central axis of the blood vessel.

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

Claims

1. A mechanical thrombectomy device, Support wire and This includes multiple thrombus traps that are eccentrically attached to this support wire, Of the aforementioned plurality of thrombus trappers, at least one thrombus trapper is: It has an extension frame with an inner wall that provides a central lumen extending from the proximal end to the distal end, and the support wire is connected to the proximal end of one thrombus capturer. When the plurality of thrombus traps are deployed in free space, the expansion frames of the plurality of thrombus traps are not concentric with each other, and the support wire extends from the proximal end to the distal end of one thrombus trap through the central lumen and along the inner wall of the expansion frame of that one thrombus trap. A thrombus trap in which, when the plurality of thrombus traps are deployed into a blood vessel, the expansion frames of the plurality of thrombus traps move in a direction in which they are pressed against the blood vessel wall and supported concentrically with each other, and the support wire is pressed against the inner wall of the expansion frame of one of the thrombus traps.

2. A thrombectomy device according to claim 1, A thrombus removal device wherein the support wire bends when the thrombus capturer is deployed into a blood vessel.

3. A thrombectomy device according to Claim 1, The plurality of thrombus capture devices include a first thrombus capture device proximal to the second thrombus capture device. A thrombus removal device in which the first thrombus capturer has a distal frame end, and the second thrombus capturer has a proximal frame end, and the distal frame end can be aligned to coincide with the proximal frame end.

4. A thrombectomy device according to claim 3, A thrombectomy device in which the gap between the distal frame end and the proximal frame end during alignment is less than 10 mm.

5. A thrombectomy device according to claim 3, A thrombus removal device in which the second thrombus capturer is equipped with a filter.

6. A thrombectomy device according to claim 1, The aforementioned support wire is The proximal segment located near the thrombus capture device, The thrombus capture device includes a distal segment extending through the central lumen, A thrombectomy device in which the proximal segment and the distal segment are connected to a radiopaque coil attached to the support wire.

7. A thrombectomy device according to claim 6, A thrombectomy device wherein the proximal segment of the support wire has a larger diameter than the distal segment of the support wire.

8. A thrombectomy device according to claim 1, The thrombus capture device comprises a stem extending from a joint in the support wire toward the proximal end of the expansion frame, and is a thrombus removal device.

9. A thrombectomy device according to claim 1, The thrombectomy device comprises a frame cell ring having an inner wall that provides a central lumen extending from the proximal end to the distal end, wherein the extension frame includes a frame cell ring.

10. A thrombectomy device according to claim 9, A thrombus removal device wherein, when the thrombus capturer is deployed into a blood vessel, the support wire is pressed against the inner wall of the frame cell ring.

11. A thrombectomy device according to claim 9, When the thrombectomy device is deployed in free space, the frame cell rings in the plurality of thrombus capturers become non-concentric with each other, A thrombectomy device in which, when deployed into a blood vessel, the frame cell rings of the plurality of thrombus capturers are biased by the blood vessel so that they are concentric with each other.

12. A thrombectomy device according to claim 1, The thrombectomy device is a cylindrical frame having an inner wall that provides a central lumen extending from the proximal end to the distal end, wherein the extension frame is a cylindrical frame.

13. A thrombectomy device according to claim 12, A thrombus removal device wherein, when the thrombus capturer is deployed into a blood vessel, the support wire is pressed against the inner wall of the cylindrical frame.

14. A thrombectomy device according to claim 12, When the thrombectomy device is deployed in free space, the cylindrical frames of the plurality of thrombus capturers become non-concentric with each other, A thrombectomy device in which, when deployed into a blood vessel, the cylindrical frames of the plurality of thrombus capturers are biased by the blood vessel so that they are concentric with one another.

Images