Blockage Removal System

Abstract

To provide an obstruction removal device having one or more engaging members which can engage multiple portions of a clot.SOLUTION: The one or more engaging members have a collapsed, delivery state, and an expanded, deployed state, and in some embodiments can be locked to maintain a fixed configuration thereof.SELECTED DRAWING: Figure 22a

Description

Related Applications

[0001] This application claims priority to U.S. Provisional Application No. 62 / 426,106 (Entitled "Occlusion Removal System"), filed November 23, 2016, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] The present invention relates to devices used to capture and remove obstructions, such as blood clots and other obstructions, from the vascular system, and the delivery of these devices to target areas within the vascular system.

[0003] The accumulation of thrombi within the vascular system can lead to the formation of blood clots, which can result in the restriction of blood supply to downstream areas of the vascular system. When clots are present within the neurovasculature, these clots can lead to stroke.

[0004] Current techniques for removing clots utilize devices designed to retain and capture the clot, followed by withdrawal of the device to physically remove the captured clot from the body. Some of these devices may fail to capture the entire clot or may dislodge the clot, causing it to accumulate elsewhere and promoting clot fragmentation, which can lead to stroke risk. Additionally, some of these devices may promote endothelial denudation due to high friction between the device and the vessel wall. Furthermore, some of these devices collapse when encountering curves within the vessel, increasing the opportunity for the captured clot to break free and / or fragment.

[0005] A need exists for an obstruction removal device that reduces the likelihood of fragmented thrombus remaining lodged within the vasculature, while maximizing the likelihood of mechanical capture of the clot and limiting the risk of endothelial denudation. Summary of the Invention

[0006] In one embodiment of the present invention, an obstruction removal device is described having a proximal axial core structure, a distal dampening structure, and one or more engagement members attached to the distal dampening structure.

[0007] In another embodiment of the present invention, an obstruction removal device is described having a proximal structure, a distal structure, and one or more connected engagement members between the two structures.

[0008] In another embodiment of the present invention, an obstruction removal device is described having a proximal structure, a distal structure, and one or more connected engaging members between the two structures, at least one of the engaging members functioning as a filter.

[0009] In one implementation of the above-described embodiment, the engagement members are substantially similar to one another.

[0010] In another implementation of the above-described embodiment, some of the plurality of engagement members are not substantially similar to other engagement members.

[0011] In another implementation of the above-described embodiment, some of the plurality of engagement members actively engage the clot, and one or more of the remaining engagement members do not engage the clot.

[0012] In one embodiment, the obstruction removal device is housed within a delivery device and delivered via a catheter.

[0013] In another embodiment, the obstruction removal device is delivered directly via a catheter.

[0014] In another embodiment, the device is used to remove foreign bodies.

[0015] In one embodiment, the obstruction removal device includes a plurality of obstruction engaging members connected to respective linkages, the linkages connecting pairs of the engaging members to one another.

[0016] In one embodiment, the obstruction removal device includes a locking mechanism for locking one or more engagement members in an expanded and / or contracted configuration. In one embodiment, the device includes a hypodermic tube pusher and a shape control element located within the pusher and spanning the length of one or more engagement elements, the shape control element being used to contract and / or expand the engagement members or to hold the engagement members in a fixed or locked state. [Brief explanation of the drawings]

[0017] These and other aspects, features, and advantages of embodiments of the present invention will become apparent and clear from the following description of embodiments of the invention, which proceeds with reference to the accompanying drawings.

[0018] [Figure 1] FIG. 1 shows an engagement member used in an obstruction removal device.

[0019] [Figure 2] FIG. 2 is another view of an engagement member used in an obstruction removal device.

[0020] [Figure 3] FIG. 3 is an obstruction removal device according to one embodiment of the present invention.

[0021] [Figure 4] FIG. 4 is an obstruction removal device according to another embodiment of the present invention.

[0022] [Figure 5] FIG. 5 is an exploded view of the obstruction removal device shown in FIG.

[0023] [Figure 6] FIG. 6 is an enlarged view of the proximal engagement member of the obstruction removal device of FIGS.

[0024] [Figure 7]FIG. 7 is an obstruction removal device according to another embodiment of the present invention.

[0025] [Figure 8] FIG. 8 is an exploded view of the obstruction removal device shown in FIG.

[0026] [Figure 9] FIG. 9 shows one of the distal engagement members used in the device shown in FIGS.

[0027] [Figure 10] FIG. 10 illustrates a method of deploying the obstruction removal device described in the above embodiment. [Figure 11] FIG. 11 illustrates a method of deploying the obstruction removal device described in the above embodiments. [Figure 12] FIG. 12 illustrates a method of deploying the obstruction removal device described in the above embodiment.

[0028] [Figure 13] FIG. 13 shows the hypodermic tubing used to create the engagement members.

[0029] [Figure 14] FIG. 14 illustrates the process used to help shape the final engaging member. [Figure 15] FIG. 15 illustrates the process used to help shape the final shape of the engaging members. [Figure 16] FIG. 16 illustrates the process used to help shape the final shape of the engaging members.

[0030] [Figure 17] FIG. 17 shows an obstruction removal device that utilizes a hypodermic tube and a shape control that allows the engagement member to assume an expanded and / or contracted configuration. [Figure 18]FIG. 18 shows an obstruction removal device that utilizes a hypodermic tube and a shape control that allows the engagement member to assume an expanded and / or contracted configuration. [Figure 19] FIG. 19 shows an obstruction removal device that utilizes a hypodermic tube and a shape control that allows the engagement member to assume an expanded and / or contracted configuration.

[0031] [Figure 20] FIG. 20 shows a hypodermic tube used in the obstruction removal device of FIGS. 17-19. [Figure 21] FIG. 21 shows a hypodermic tube used in the obstruction removal device of FIGS. 17-19.

[0032] [Figure 22a] FIG. 22a illustrates an obstruction removal device that utilizes a retainer element that is used to hold the posts of the engagement members used in the obstruction removal device. [Figure 22b] FIG. 22b illustrates an obstruction removal device that utilizes a retainer element that is used to hold the posts of the engagement members used in the obstruction removal device. [Figure 23] FIG. 23 illustrates an obstruction removal device that utilizes a retainer element that is used to hold the posts of the engagement members used in the obstruction removal device.

[0033] [Figure 24a] FIG. 24a shows an obstruction removal device with an engagement member that utilizes a hypodermic tube with a notch and a shape control with a ridge that is used to lock the engagement member. [Figure 24b] FIG. 24b shows an obstruction removal device with an engagement member that utilizes a hypodermic tube with a notch and a shape control with a ridge that is used to lock the engagement member. [Figure 25a]FIG. 25a shows an obstruction removal device with an engagement member that utilizes a hypodermic tube with a notch and a shape control with a ridge that is used to lock the engagement member. [Figure 25b] FIG. 25b shows an obstruction removal device with an engagement member that utilizes a hypodermic tube with a notch and a shape control with a ridge that is used to lock the engagement member. Detailed Description of the Invention

[0034] Specific embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like reference numerals indicate like elements.

[0035] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms as commonly defined in dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art, and will not be interpreted in an idealized or very formal sense unless explicitly defined herein.

[0036] For purposes of understanding the terminology described below, the terms "clot," "thrombus," "embolus," and "obstruction" may be used synonymously. Although an obstruction removal device is described, the device may also be used to capture a clot, thrombus, embolus, foreign body, or other object. The engagement members of the device may engage a clot, thrombus, embolus, foreign body, obstruction, or other object.

[0037] 1 and 2 illustrate engagement members 100 for use with the obstruction removal devices of the present invention. One or more engagement members are used as part of the obstruction removal device to engage thrombus that may have accumulated within the vasculature. The overall shape of the engagement members may include, but is not limited to, round, oval, elliptical, hourglass, spherical, basket, stent, counter, square, prismatic, and cage shapes. Each engagement member 100 has a number of struts 101 defining a number of cells or openings 102 and a pair of opposing holes 103, 104. For purposes of formality, hole 103 will be referred to as the distal hole and hole 104 will be referred to as the proximal hole.

[0038] Each engagement member may be uniquely configured with different struts, cells, cell sizes, materials, and / or shapes. The strut designs may have straight, wavy, sinusoidal, or zigzag patterns, or may have an asymmetrical design (i.e., a design in which the struts on one side of the engagement member are not a mirror image of the struts on the other side of the same engagement member). An asymmetrical strut design may help facilitate the rotational component of the member's progression through the vessel by shifting the engagement member's center of gravity from the engagement member's geometric center. This ease of rotation facilitates the engagement member, i.e., the obstruction removal device, to move easily through anatomy, particularly after engaging a clot and as the device is being withdrawn through the vasculature. This ease of rotation may also limit the amount of damage to the vessel wall due to high contact friction by limiting damage to specific sections of the vessel wall. The engagement members may have similar or unique designs on each end of the engagement member. This can be done by varying the strut and / or cell shape and / or cell density at each end, e.g., by increasing cell size at one end and decreasing cell size at the other, allowing for different properties and enhanced ability to engage clots or track engagement and obstruction removal devices deployed through the vessel.

[0039] FIG. 2 illustrates an engaging member 100 having multiple struts 101 of varying thickness. More specifically, multiple distal struts 101a branch off from the material defining the proximal bore 104, with one or more of these struts 101a branching off to form struts 101b. Struts 101b are shown with features 105 protruding from them. Feature 105 may be any interruption in the otherwise continuous surface of strut 101. Non-limiting examples include barbs, ridges, projections, spikes, prongs, nubs, etc. Struts 101b are then shown to merge with adjacent struts 101b to form thicker struts 101c, which then branch off to form additional struts 101d, again shown with features 105. These struts 101d then meet again to form thicker struts 101e, which are connected to define distal bores 103. Thus, in this particular embodiment, it can be seen that multiple struts are connected to each other to form a web of struts spanning from proximal bores 104 to distal bores 103.

[0040] Another strut configuration may utilize a single strut pattern, such as a continuous, helical strut configuration that runs between the proximal and distal ends of the engaging member or runs for a portion of the length from the proximal to the distal ends of the engaging member.

[0041] Each engagement member has a collapsed configuration when stored within the delivery device, and when not stored, has an expanded configuration as shown in Figures 1 and 2. Each engagement member is capable of self-collapse and self-expanding based on whether an external force is applied that constrains the expansion of the engagement member (as would be the case when stored within the delivery device) or if no constraining force is present (as would be the case when not stored).

[0042] The engaging members may be formed from Nitinol or a similar material and may be laser cut to achieve the contoured shape. Other materials and other cutting and / or machining processes are within the scope of the present invention.

[0043] Distal and proximal holes 103 and 104 on the distal and proximal ends, respectively, of the engaging members can facilitate placement of a common rod on which each engaging member is placed, and may also be fitted with separate connecting pieces for connecting the engaging members to multiple components of the obstruction removal device.

[0044] 3 shows an obstruction removal device 200 according to one embodiment of the present invention. The obstruction removal device includes a proximal core structure 201 at one end of the device, a distal cushioning structure 202 connected to the proximal core structure 201, and one or more engagement members 203 attached to the distal cushioning structure 202. In one embodiment, the device is pushed and / or pulled from the end of the core structure 201. A pusher may be located below the core structure, or the core structure itself may function as a pusher.

[0045] The core structure 201 may be formed from a variety of materials, including, but not limited to, Nitinol, stainless steel, cobalt chrome, or polymeric materials such as PTFE, Pebax, TPE, Engage, polyethylene, or other similar materials. The core structure configuration may include, but is not limited to, a coiled structure, a braided structure, or a combination coiled / braided structure.

[0046] The buffer structure 202 may be formed from a radiopaque material, including, but not limited to, platinum, tantalum, palladium, or other similar materials. While radiopaque materials may be used, radiopaque materials are preferred because they may facilitate easier imaging of the device during the device insertion procedure. An engagement member attached to a buffer structure formed from a radiopaque material aids in imaging of the device during the clot removal procedure. The engagement member may be attached to the buffer structure in several ways. For example, the buffer structure may have a threaded outer profile, with the hole in the engagement member having a corresponding receiving structure that is rotationally engaged with the threaded outer profile of the buffer structure. Alternatively, the buffer structure may have a non-threaded configuration, and the engagement member may be secured to the buffer structure by a heat treatment process, such as welding. Other mechanical means or other heat treatment processes may also be used to secure the engagement member to the buffer structure.

[0047] FIG. 4 illustrates an obstruction removal device 300 according to another embodiment of the present invention. The obstruction removal device 300 includes a proximal structure 301 connected to one or more engagement members 303. There may be a distal structure 302 attached to a distal-most engagement member (labeled 306 for clarity; the distal-most engagement member 306 may be structurally the same as or different from the other engagement members 303). The one or more engagement members 303 are connected to the proximal structure such that the one or more engagement members 303 are rotatable independently of the proximal structure 301. The one or more engagement members 303 may be coupled to one another such that they are rotatable independently of one another, as described in more detail below. Preferably, the obstruction removal device 300 is pushed / pulled from one end of the proximal structure 301, and thus the terms proximal structure and distal structure are used relative to the pushing / pulling end. While five engagement members are shown in the figure, fewer or more engagement members may be used. As with all of the embodiments described herein, the engagement member 303 is constructed from one or more posts 101, as described above.

[0048] FIG. 5 is an exploded view of the embodiment of the obstruction removal device 300 of FIG. 4. The proximal structure 301 may include a core wire 307 positioned inside a coil 309, which may be positioned inside a tube 310. The core wire 307 has a flared end 308. The core wire 307 may be formed of nitinol or a similar material, although other materials are within the scope of the present invention. The coil 309 may be formed of tantalum or other radiopaque material, although radiolucent materials may be used. The tube 310 may be formed of PET or other polymeric material, although non-polymeric materials may be used as well. The proximal structure also includes another coil 311, preferably spaced more open than the coil 309 and formed of a similar material. The coil 311 is positioned between the core wire 307 and its outer core 309, supporting the central core wire 307 within the coil 309. Proximal structure 301 is connected to a proximal engaging member 302, which in turn may be connected to another engaging member if more than one engaging member is used in the obstruction removal device.

[0049] The distal structure 302 includes a monofilament 315 positioned inside a coil 316. Alternatively, multiple monofilaments may be bonded together to form the monofilament structure 315. The monofilament 315 may be formed from a stretch-resistant polymer such as Engage, although other materials may be used. The coil 316 may be formed from tantalum or other radiopaque materials, although radiolucent materials may also be used. An adhesive (preferably a UV-curable adhesive) 317 is used on both ends of the coil structure 316 to hold the monofilament 315 together within the coil 316. In one embodiment, the distal structure can function as a guidewire.

[0050] The distal structure 302 may be connected to the distal-most engagement member 306. This distal structure may be radiopaque to aid in imaging the device during deployment. In the embodiment of FIG. 5, the coil of the distal structure 302 fits within the bore 103 of the distal-most engagement member 306, and a retention piece 312 fits on the other end, holding the distal portion 302 together with the engagement member 306. The retention piece is welded within the bore 103 structure. The engagement member 306 is still rotatable. The retention piece may be a tubular structure and may be made from nitinol, although similar materials could be used. To aid in imaging, the retention piece may be made from nitinol filled with a radiopaque material. Alternatively, the retention piece may be coated with a radiopaque material to aid in imaging the device during the procedure. Alternatively, the retention piece may be made from a radiopaque material.

[0051] The connection mechanism used to connect the engaging members together is shown in Figures 5 and 6. Figure 6 shows the connection structure of the engaging member 303 connected to the proximal structure 301 of the obstruction removal device.

[0052] The connection mechanism includes a link 313 having two flared ends 314 and a retaining piece 312. The link 313 may be formed from stainless steel, although similar materials may be used. The flared ends extend into opposing holes 103, 104 of the connecting members, and the retaining piece 312 fits next to the flared end 314 to retain the link 313 within the holes of the connecting members. This connection structure is used to connect the connecting members when more than one connecting member is used in the obstruction removal device. The retaining piece 312 is welded to the hole, and the link is held within the holes of the connecting members, but is rotatable. Multiple connecting members may be independently rotatable.

[0053] 5 and 6, engaging member 303 is connected to proximal structure 301. Flared end 308 of core wire is positioned to pass through hole 104 in engaging member 303, and retaining piece 312 is positioned outside core wire 307 to secure proximal structure 301 to engaging member 303. Retaining piece 312 is also welded within hole 104. A smaller, gapped coil 311 is positioned within the distal end of coil 309 and serves to aid in centering core wire 307 within coil 309.

[0054] In one embodiment, the connecting piece 313 is placed within the bore structure, and the retaining piece 312 is welded within the bore on the outside of the connecting piece. The flared end 313 may then be laser welded onto the end of the connecting piece. In another embodiment, the retaining piece 312 is welded within the bore, the connecting piece is placed within it, and the flared end is laser welded. While laser welding is mentioned, other similar heat treatment techniques may be used as well. This procedure may also be used on the end of the core wire 307 to form the flared end 308 and connect the proximal-most engaging member 303 to the proximal portion 301 of the device. In one embodiment, this procedure may be used on the end of the coil 316 when connecting the distal portion of the device to the distal-most engaging member 306.

[0055] Each engagement member has a rotating component, and this rotational ability can assist in capturing the thrombus and maneuvering it through the vessel. This can also help limit the amount of endothelial denudation that may occur as the device is pushed and / or pulled through the vessel by helping to limit any excessive force due to high contact friction between the struts and the vessel wall. The engagement members may also be configured with a more rounded, smoother profile (as shown), eliminating any sharp edges on the engagement members that promote denudation due to high contact friction. Furthermore, the spacing between the engagement members results in less material coming into physical contact with the vessel than other designs that utilize, for example, a longer, single-piece clot engagement unit. Having less material in contact with the vessel also serves to limit endothelial denudation during the clot removal procedure.

[0056] In one embodiment, the proximal portion 301 of the obstruction removal device may comprise means for detaching the engagement member from the obstruction removal device. The detachment means may be provided on a portion of the proximal portion 301 that contacts the engagement member 303 (the most proximal engagement member) and may comprise electrolytic, mechanical, thermal, or other means known in the art for inducing severing and / or disassembly of the linkage.

[0057] One or more of the engaging members actively engage the clot, while others may be located further distal to the clot or proximal to the clot, depending on the size of the clot and the number of engaging members used on the device. Due to potential variations in the individual shape or configuration of each engaging member, as well as the number of engaging members used in the obstruction removal device compared to the size of the clot, one or more of the engaging members may be located distal to the clot and have a dense cell configuration that acts as a filter to trap any clot that may become dislodged when the obstruction removal device is used to capture the clot.

[0058] The one or more engagement members acting as a filter may have a mesh configuration that spans the entire engagement member or may be located on one specific side of the engagement member to maximize the chance of capturing loosened thrombus without displacing the thrombus. In one embodiment, the one or more engagement members acting as a filter have a dense cell configuration on a more distal portion of the member to capture thrombus dislodged from the intersection of the clot with the more proximal engagement member. This arrangement may be useful when the more proximal engagement member intersects with the clot and multiple portions of the clot become soaked and softened. The more distal engagement member having a filter configuration can particularly capture soaked and softened thrombus that may accumulate in the bloodstream. The engagement members acting as filters may be formed from nitinol, stainless steel, or similar materials.

[0059] Alternatively, they may be formed from laser-cut polymers. Alternatively, these engagement members, which function as filters, may have a reverse-braided configuration, other cage lattices, or other configurations known in the art of embolism protection devices. One or more engagement members may also be constructed from or coated with a thrombogenic material to aid in clot retrieval procedures by promoting adhesion between the engagement member and the thrombus. Alternatively, non-thrombogenic materials or coatings may be used to aid in the breakdown of portions of the clot that come into contact with the engagement member. This may be useful, for example, in retrieval procedures involving entrapment of large clots.

[0060] Figures 7 and 8 illustrate another embodiment of an obstruction removal device utilizing one or more engagement members that function as a filter to capture dislodged thrombus during a clot removal procedure. Figure 7 illustrates an obstruction removal device having a proximal portion 401 and a distal portion 402. The proximal portion includes a plurality of engagement members 303. The distal portion includes engagement members 407 and 408. Distal engagement members 407 and 408 generally have a high-density cell configuration that functions as a filter to capture dislodged thrombus that may be scraped off during the clot removal procedure described above. The high-density cell configuration is due to the inner and outer structures used to form the engagement members, as shown in Figure 8.

[0061] As shown in FIG. 8, the two distal engagement members 407 and 408 are each comprised of an inner structure 409 and an outer structure 410, with the inner structure nested within the outer structure. The inner structure 409 and outer structure 410, including the distal engagement members 407 and 408, may be formed from laser-cut nitinol or a similar material. The proximal and distal portions 401 and 402 are configured similarly to the embodiment shown in FIGS. 4-5, as are the linkages between each of the engagement members; this filter engagement member configuration may be applied to any of the engagement members present in any of the provided obstruction removal device embodiments.

[0062] The cell patterns may be slightly offset in the inner and outer structures to create a denser cell profile when the inner structure is nested within the outer structure. As shown in FIG. 9, the distal portion 510 of the engagement member 408 has a denser cell profile than the proximal portion 511 to capture dislodged thrombus that may escape during a clot removal procedure. This arrangement may be useful when the more proximal engagement member intersects the clot, immersing and softening portions of the clot. The more distal engagement member with a filter configuration can capture the immersed and softened thrombus that may accumulate in the bloodstream. While FIGS. 7 and 8 show two engagement members with inner and outer configurations that function as filters, more or fewer engagement members may have this filter configuration.

[0063] In one embodiment for delivery of the devices described above, the obstruction removal device is housed within a delivery device, and the delivery device is delivered via a catheter. In one example, the delivery device may be a microcatheter. The delivery device is delivered to the side of the obstruction and then retracted. Retraction of the delivery device ejects the obstruction removal device from the delivery device, causing the engagement member to expand upon retraction of the delivery device.

[0064] Alternatively, the obstruction removal device may be pushed outward from the delivery device, which then allows the engagement members to expand. Depending on the number of engagement members on the obstruction removal device, the size of the clot, and the location of delivery relative to the obstruction, some members may be located further distal to the obstruction and / or proximal to the proximal end. The obstruction removal device may be steerable via a core wire. Once the obstruction removal device engages the obstruction, the delivery device is pulled to a point just past the distal end of the catheter, after which the catheter is withdrawn. Alternatively, the obstruction removal device may be withdrawn from the vasculature by retracting the delivery device into the catheter and then withdrawing the catheter, or by withdrawing the delivery device and / or the obstruction removal device through the catheter. Alternatively, the catheter may be withdrawn as a whole to remove the delivery device and the obstruction removal device. In other embodiments, the delivery device may be a hypodermic tube.

[0065] In an alternative embodiment, the device may be delivered directly via a catheter without being housed within a delivery device.

[0066] 10-12 illustrate one embodiment of a specific method for deploying an obstruction removal device. In this embodiment, a delivery device 602 is delivered through the vasculature 600 to the side of a clot 601. The obstruction removal device 603 is pushed through the delivery device toward the side of the clot. While this particular embodiment shows the obstruction removal device positioned midway through the clot, the device may be positioned within the clot or at a location proximal or distal to the location of the clot. Depending on the size of the clot and the number of engagement members used in the obstruction removal device, some engagement members may be located further beyond the distal end of the clot or proximal to the proximal end. The delivery device 602 is then retracted, allowing the engagement members of the obstruction removal device to expand and cross multiple portions of the clot. The obstruction removal device 603 may be manipulated by the operator from the proximal portion 604 of the device. Once the obstruction removal device has secured the clot, it is retracted as described above. Suction may also be used to assist in the clot / obstruction removal procedure. Figures 10-12 show a specific example for illustration. It is contemplated that other delivery methods, such as pushing the obstruction removal device from the delivery device, are within the scope of the present invention.

[0067] The engagement members may all be the same size, all different sizes, or some engagement members may be different sizes from one another. In one embodiment, the diameter range of the spherically shaped engagement members may be between 1-12 millimeters. In another embodiment, a diameter range of 3-6 millimeters is used.

[0068] The engagement member is formed from hypotubing that has been laser cut into a specific pattern based on the shape of the cells 102 and struts 101. This hypotubing 700 is shown in FIG. 13. The hypotubing is heat-treated; in one embodiment, the hypotubing may be heat-set at 530-550 degrees Celsius for five minutes. The hypotubing is then quenched in water and allowed to cool. An expansion plunger 702 is then inserted and used to expand a section of the hypotubing (see FIG. 14). The expanded hypotubing is then heat-set to this expanded shape. In one embodiment, the hypotubing is heat-set at 530-550 degrees Celsius for three minutes. The expanded hypotubing is then quenched in water. Depending on the size of the engagement member, the expansion plunger and subsequent heat-treatment process may be performed on multiple sections of the engagement member, with each section being heat-set after expansion. An inflation pin 704 is then inserted into the hypotube to assist in the expansion of the hypotube walls (see FIG. 15). The inflated hypotube 700 is placed into a fixture. The fixture includes two plates 706, 708. A threaded rod connects the two plates, which have nuts attached to the outside. To further expand the hypotube, the nuts are tightened, applying pressure to the two plates simultaneously. Once the proper shape is set, the inflated hypotube can be heat treated (in one embodiment, at 530-550 degrees for 5 minutes) and then quenched to set the shape of the engagement members.

[0069] The engagement members are then removed, etched, and electropolished to set the final shape of the members. The obstruction removal device is then assembled with one or more capture members. Although the engagement members are heat cured and processed to assume an expanded shape, they maintain a high shape memory due to factors such as material properties and strut thickness. Thus, the engagement members assume an expanded shape when unconstrained (i.e., not contained within a delivery device), and a contracted shape similar to the initial shape of the hypodermic tube when constrained (i.e., contained within a delivery device).

[0070] In some of the above-described embodiments of the obstruction removal device, the engagement members are self-expandable when released from a delivery device (e.g., a microcatheter) and self-collapseable when retracted within the delivery device. In some embodiments and situations, it may be useful to have a locking mechanism for locking one or more engagement members in the expanded and / or collapsed configuration. Neurovascular vessels are small and complexly tortuous. When an obstruction removal device and associated engagement members are used to remove blood clots within neurovascular vessels, the geometry of the vessel may prevent the engagement members from fully opening or may cause the engagement members to prematurely collapse after retaining the blood clot when the device is pulled back through the vascular system for evacuation outside the patient's vasculature. A locking feature that locks the engagement members in the expanded configuration would address these issues.

[0071] For purposes of the illustration of the figures detailed below, unless otherwise specified, anything on the left side of the drawing will be considered to be distal (or the direction of further placement into the vasculature) and anything on the right side will be considered to be proximal (or the direction in which vascular access is gained).

[0072] 17 is generally similar to the above-described embodiment, but further includes a mechanism for manipulating or maintaining the shape of the engagement members 802a-802d in the expanded position. The device 800 includes multiple engagement members 802a-802d (e.g., four members) connected to one another to form a linear configuration. The most proximal engagement member 802d is connected to the distal end of an elongated pusher 806.

[0073] The manipulation mechanism is controlled by a shape-controlling member 808 that is connected to the distal end of distal engagement member 802d, extends through each of engagement members 802a-802d, extends through a passage within pusher 806, and terminates at or near the proximal end of pusher 806. In this embodiment, the physician pulls on shape-controlling member 808 to pull engagement members 802a-802d against the distal end of pusher 806, thereby maintaining the expanded configuration of the engagement members.

[0074] Preferably, the pusher is an elongated body having a diameter suitable for passage through a catheter or sheath and further includes a lumen or passageway for housing shape control portion 808. Similar to the previously described embodiment best shown in FIG. 1, each of engagement members 802a-802d includes proximal and distal openings 103 and 104 that are aligned with one another along the longitudinal axis of device 800 and that are aligned with the passageway of pusher 806. Each engagement member 802a-802d also includes a tubular element 804a-804d (e.g., a metal hypodermic tube) connected only to the distal or "left" end of each engagement member (alternatively, only to the proximal end of each engagement member) but not to the other side of engagement member 802a-802d. The tubular elements 804a-804d are aligned with one another so that their own internal passages connect between the proximal and distal openings of each of the engagement members 802a-804d. In this embodiment, the passages are created through the pusher, the engagement members 802a-802d, and the tubular elements 804a-804d. Various techniques can be used to connect the tubular elements 804a-804d to the engagement members 802a-802d, including adhesive bonding, soldering, or mechanical screws.

[0075] Shape control section 808 passes through this path, which includes threading through the lumen of the pusher, engagement members 802a-802d, and tubular elements 804a-804d. The distal end of shape control section 808 is attached to distal cap 810 at the distal end of distal-most engagement member 802a. Gluing, welding, or mechanical screw concepts may also be used to achieve this attachment, and preferably cap 810 has a diameter larger than the diameter of the distal opening of distal engagement member 802d. Alternatively, shape control section 808 may be mechanically attached directly to the distal end of distal engagement member 802a.

[0076] Shape control 808 is movable separately from pusher 806 because the control is disposed within the lumen of the pusher, allowing a user to independently and separately move control 808 longitudinally relative to pusher 806. Pusher 806 is used to control the position of the entire obstruction removal device, including attached / coupled engagement members 802a-802d, while control 808 is used to control the shape of engagement members 802a-802d. Preferably, shape control 808 is a wire, flexible rod, or similar elongated element having a length extending between the distal end of the device and at least the proximal end of the device.

[0077] Because shape control 808 is connected to distal cap 810, pushing control 808 applies a distal force against cap 810 (or the tip of distal engaging member 802a, if such a cap is not used). Because tubular elements 804a-804d are secured only to the left or distal side of the engaging member, tubular elements 804a-804d release contact with the proximal ends of the engaging member and move distally, as shown in FIG. 18 , as engaging members 802a-804d become oval or elongated. Conversely, pulling or retracting control 808 creates an opposite proximal force against cap 810 (or distal engaging member 802a, if such a cap is not used), causing engaging members 802a-802d to radially expand toward a spherical shape until the free or proximal ends of tubular elements 804a-804d contact the interior proximal surfaces of the engaging member. This prevents any further expansion by the engagement members 802a-802d or further proximal movement by the shape control unit 808. In this manner, the attached tubular elements 804a-804d function to resist excessive expansion of the engagement members 802a-802d. In one embodiment, the tubular elements 804a-804d are attached to only one end of the engagement members 802a-802d (e.g., the left or distal end of the engagement member), and further, the particular attached end may be constructed of a dense, weighted material that provides some resistance to movement in a particular direction. For example, the tubular elements 804a-804d are attached to the distal ends of the engagement members 802a-802d, and the distal end of each engagement member is weighted to naturally resist natural forces due to movement through the vasculature that would tend to collapse the retraction member. Thus, even if the user does not use the shape control to expand or collapse the engagement member, the presence of the tubular element causes the engagement member to naturally resist changes in shape.

[0078] While in use inside a patient, shape control 808 can be used to prevent collapse of engagement members 802a-802d, particularly through curved or tortuous areas. However, it may be desirable for the user to also have the ability to collapse engagement members 802a-802d during withdrawal of device 800 (e.g., into a sheath or catheter).

[0079] In one embodiment, control 808 includes a collet or other locking feature at its proximal end that allows a user to lock the position of the control relative to pusher 806 and also lock the shape of the engagement members. Other embodiments may omit the locking feature and instead rely on the user applying force to control 808 to manipulate engagement members 802a-802d to form and maintain a particular shape.

[0080] Figure 19 shows an alternative embodiment of device 801 that is generally similar to device 800 described above. However, tubular elements 804a-804d are instead secured to the proximal (or right) ends of engaging members 802a-802d instead of the distal (or left) ends of engaging members 802a-802d as shown in Figure 18. In this embodiment, pushing control 808 similarly collapses engaging members 802a-802d, while pulling control 808 similarly expands the engaging members.

[0081] In one embodiment, push tube 806 is a tapered nitinol hypodermic tubing having an inner diameter of approximately 0.004 inches and an outer diameter of approximately 0.015 inches, and shape control element 808 is a wire with an outer diameter of approximately 0.003 inches. The wire can be made from a variety of materials, including metals, fibers, and polymers such as nitinol, stainless steel, Vectran, Kevlar, PET, and polypropylene. These sizes may be increased or decreased based on the size of the obstruction removal device, and these sizes are provided for illustrative purposes only. Shape control element 808 can also take the form of a wire, hypodermic tubing, or other element. The proximal end of shape control element 808 can also include a handle or similar user interface to allow for easier manipulation by the user.

[0082] In one embodiment, the tubular elements 804a-804d are radiopaque to aid in imaging. Radiopaque materials such as platinum, tantalum, palladium, or gold can be used. Imaging is useful because it allows a physician to determine whether the engagement members are collapsed or expanded based on the relative positions of the tubular elements to one another. As shown in FIGS. 18-19, when the engagement members are collapsed, the tubular elements 804a-804d are spaced apart and in a spaced-apart configuration. By utilizing imaging techniques when the tubular elements are radiopaque, a physician can visualize the spaced-apart tubular element configuration shown in FIG. 20 and confirm that the engagement members are collapsed. In contrast, when the retraction members are expanded (as shown in FIG. 17), the tubular elements 804a-804d are relatively close together, forming a continuous straight line, as shown in FIG. 21, confirming that the engagement members are expanded. In this way, the physician can use imaging to confirm whether the engagement members are collapsed or expanded.

[0083] Other embodiments may utilize coil elements spanning the length of each engagement member 802a-802d in place of the tubular elements 804a-804d. The advantage of coil elements is that they can be attached to both ends of the engagement members, and the coil's ability to expand and contract allows the engagement members to collapse or expand. Alternatively, coil elements may be used like the tubular elements 804a-804d of FIGS. 17-21, with one end of the coil fixed to the engagement member 802a-802d and the other end free.

[0084] As discussed above, the presence of the coil or tubular element is beneficial because it naturally resists collapse of the engagement member. Thus, the coil or hypodermic tube can be considered a tensioning member that helps resist collapse of the engagement member. However, one embodiment may omit the coil or tubular element and instead utilize control unit 808 as the sole mechanism for controlling the shape of the engagement element. This embodiment allows the user to control the shape of the engagement member, but there is no "locking" mechanism to prevent the engagement member from being excessively radially expanded by shape control unit 808.

[0085] 22a, 22b, and 23 show a device 803 that is generally similar to the above-described embodiments 800 and 801. However, rather than relying on a user to maintain the position of the shape control or a separate collet mechanism to lock the shape control 808 (and thus lock the engagement members 802a-802d in a particular shape), the control 808 includes a locking element 812 that can engage or latch with a portion of the engagement members to lock the engagement members in a particular shape.

[0086] Similar to the embodiment of FIGS. 17-21, this system utilizes a proximal pusher 806 and a shape control 808 that passes through the pusher 806, across a series of engaging members 802a-802d, and exits the distal end of the pusher. The control 808 is configured as star-shaped retaining members 812a-812d and includes multiple (e.g., four) fasteners that are each secured to the control within the engaging members 802a-802d (i.e., each engaging member has a retainer therein). The shape control 808 is connected to the distal end of the distal cap element or to the distal-most engaging member 802a such that pushing the control 808 causes the engaging members to collapse, while pulling the control 808 causes the engaging members to expand. Because the retaining members 812a-812d are secured to the control, displacement of the shape control 808 also displaces the retainers. In this embodiment, the retaining member provides a backstop mechanism that limits how far control portion 808 can be withdrawn proximally, thereby also limiting the shape and radial expansion of engagement members 802a-802d.

[0087] As shown in detail in FIG. 22b, star-shaped retainers 812a-812d include passages 815 through which shape control 808 passes. Mechanical means, such as welding or adhesive bonding, can be used to connect the retainers to the control, or alternatively, the retainers can be integrally formed on shape control 808. The retainers include a plurality of curved, radial recesses, indentations, or slots 816, which contribute to the retainer's overall star-shaped shape. Additionally, retainer 812 includes a tapered proximal side and a flat distal side. Because retainers 812a-812d are positioned on shape control 808, retracting or pulling the control displaces retainers 812, allowing them to engage with the distal posts of their respective engagement members 812. The retainer recesses 816 are sized to engage with or partially capture the posts of the engagement members. Thus, pulling on control unit 808 causes retention members 812a-812d to contact the posts of the engagement members, causing the posts to be retained within slots / recesses 816 of retention members 812. Retention members 816 may be formed from a variety of materials, including nitinol, stainless steel, polymers, or radiopaque materials such as tantalum, platinum, palladium, or gold.

[0088] The recess 816 may be sized wider than the post or slightly larger than the size of the post to directly accommodate the post. Alternatively, the slot / recess 816 may include a tapered, conical proximal side generally similar to the inside of the engagement member 812 but curving in the opposite direction, allowing the two surfaces to interlock.

[0089] Device 803 can be configured so that the post locking function is permanent or temporary. For example, in a permanent locking design, the post is permanently locked by the retaining member, which also locks control 808. In a non-permanent / temporary locking design, the user applies sufficient force (e.g., by pressing control 808 with enough force to overcome the locking force) to release the post from recess 816 in retaining member 812 and unlock the system.

[0090] When shape control 808 is pulled proximally, retention members 812a-812d engage the proximal struts (or struts on the right side, as viewed from the perspective of the drawing) of engagement members 802a-802d, locking the engagement members in the expanded configuration, as shown in FIG. 23. This feature can also be used to lock the engagement members in a collapsed state; by pressing control 808, the retention members engage the distal (left side, as viewed from the perspective of the drawing) struts, collapsing the engagement members. The proximal and distal strut configurations, best shown in FIG. 1, are arranged in a bulbous, petal-like shape with five strut regions 101 emanating from holes 103 / 104. Retention member 812 also includes five recessed regions 816, each corresponding to one strut region. Other embodiments may utilize different strut patterns and different numbers of recesses 816 to accommodate different strut patterns.

[0091] It should be noted that the above-described embodiments of engagement members include those in which the engagement members are located along a common core member (e.g., FIG. 3 ), and further include those in which separate linking elements connect pairs of engagement members to one another (e.g., FIGS. 5-6 ). Either embodiment may be used with the locking or shape-changing features described above in connection with shape control 808. When a common core member (e.g., as shown in FIG. 3 ) is used across all engagement members, control 808 may be used at a predetermined location on the larger tubular structure shown, or the control may take the form of the common tubular core structure shown within which the various engagement members are disposed. When separate linking elements 313 are used to connect multiple pairs of engagement members to one another (e.g., as shown in FIG. 5 ), each linking element 313 may utilize a lumen that houses shape control 808.

[0092] Other embodiments may utilize retainers that are located partially around the periphery of the shape control (e.g., using only the top or bottom of retainers 812a-812d), in which case the retainers engage with only some of the posts. Additional embodiments may utilize only one retainer, such as a distal retainer that locks the distal engagement member or a proximal retainer that locks the proximal engagement member. While multiple retainers increase the locking force for each engagement member, a single retainer embodiment may simplify the locking action while providing some locking force for multiple engagement members.

[0093] In one embodiment, both collapse and expansion locking are possible, such that the engagement members can be locked in both expanded and collapsed states. In another embodiment, only collapse locking is possible. In another embodiment, only expansion locking is possible. The locking possibilities can be controlled based on various variables, including the position of the retainers 812a-812d within each engagement element 802a-802d, the size of each retainer, and the overall displacement of shape control 808. In one embodiment, a collet locking mechanism at the proximal end of shape control 808 may also be used in conjunction with the retainer concept to further augment the locking force that locks the engagement members.

[0094] 24a and 24b illustrate another embodiment of a clot removal device using a shape control 808 similar to that described in the previous embodiment, but using a different locking mechanism to maintain the position of the shape control 808. In particular, one or more extensions 818 are provided on the shape control 808 and can engage with or enter channels 820 (e.g., openings, grooves, or recesses) in the tubular pusher 806, thereby locking the shape control 808 in its longitudinal position. Preferably, the area of ​​the lumen opposite and adjacent to the channel 818 is shaped, e.g., beveled or ridged, to help bias or guide the extensions 818 into the channel 820. While one channel 820 is shown, two channels are also possible, with locking or detent positions arranged to maintain the engagement member 802 in either the collapsed or expanded position.

[0095] As with the other embodiments, shape control 808 is connected to the distal-most engagement member (or alternatively, the distal cap) such that pulling the control expands engagement member 802, while pushing the control collapses engagement member 802. To lock the engagement member in the expanded configuration, a user can pull or push control 808 so that extension 818 reaches and moves into channel 820, thereby locking the position of the engagement member.

[0096] 25a and 25b show an alternative locking embodiment in which a channel is not used. Instead, the extension 118 is constructed of a somewhat malleable material that allows it to be press-fit into the tip of the push tube, but prevents further withdrawal of the extension. Optionally, the extension may have a tapered distal end to facilitate entry into the push tool 806 but prevent withdrawal. The inner lumen of the push tool 806 may also be tapered so that its distal end is slightly larger than its more proximal section, preventing proximal movement of the extension 818 beyond a certain point and thus maintaining the extension 818's configuration. In one embodiment, once the engagement member 802 is locked, this configuration is permanent. In another embodiment, the user can remove the extension 818 from the retention structure and apply sufficient force to unlock the position of the engagement member.

[0097] While the immediately preceding embodiment functions only to lock the engagement members in the expanded configuration, other embodiments can also, or alternatively, utilize a distal tubular structure to lock the engagement members in the collapsed configuration. In these embodiments, a distal tube (e.g., similar to the distal tubular structure of FIG. 5) is connected to the tip of the distal-most engagement member, and this tubular structure utilizes the same retention mechanism as in FIGS. 24-25 to lock the extension along shape control 808. In this manner, the engagement members can be locked in either the expanded or collapsed configuration. Alternative embodiments can utilize only this distal retention structure, such that the engagement members are locked only in the collapsed state.

[0098] This embodiment may be used within the link structure 313 (see FIG. 5) in embodiments in which multiple pairs of engagement members are connected via the link structure. In this embodiment, the link structure 313 also utilizes the configuration of FIGS. 24-25, and there are multiple extensions 818 along the control section 808 (e.g., four engagement members and four extensions, each functioning to lock an engagement member). The shape control section 808 is pushed / pulled so that the extensions 818 engage with the locking structures and lock the expanded and / or collapsed configurations of the engagement members. Multiple locking structures further increase the locking force required to maintain the engagement members in a particular shape, but increase the complexity of the locking mechanism. The advantage of a single locking mechanism (located on the push tool 806 or on the distal tubular structure connected to the distal or most distal engagement member) is that a single locking structure can be used to lock multiple engagement members while potentially allowing the user to unlock the engagement members by applying sufficient force. Generally, in most situations, it will be beneficial to the user to be able to selectively lock or unlock the shape of the engagement member, for example, locking the engagement member in an expanded shape to aid in clot retention, and then unlocking the engagement member to allow it to collapse and be placed into a sheath for withdrawal from the vasculature once the clot / obstruction removal procedure is complete.

[0099] In another embodiment, the locking mechanism is adjusted to allow the operator to use the diameter of the vessel to determine the appropriate diameter of the engagement member and lock the engagement member at the appropriate diameter. In this way, the operator can change the diameter based on changes in the anatomy (e.g., as the device moves from the smaller diameter M2 segment of the middle cerebral artery to the larger diameter M1 segment, the operator has the option of "anchoring" the device at the larger diameter corresponding to the larger size of the M1 segment).

[0100] In another embodiment, the locking mechanism is designed to allow for various resistances at the operator's discretion. If the operator feels that the resistance is too high when withdrawing the obstruction removal device, he or she can temporarily "relax" the locking mechanism, allowing for greater flexibility of the engagement members and reduced resistance. For example, the locking mechanism may have the flexibility to lower the resistance while still holding the engagement members in an expanded and / or collapsed configuration, or it may be "loosened" to lower the resistance.

[0101] In alternative embodiments, the devices described in the above embodiments may be used to extract foreign objects in addition to blood clots or other obstructions. Situations may arise where a foreign object, such as an embolic coil typically used to fill an aneurysm, breaks off or becomes dislodged from within the vasculature. The devices may be used to extract the foreign object using procedures similar to those used to remove the obstruction.

[0102] While the above-described embodiments disclose various mechanisms for locking the shape control portion in a longitudinal position, it should be understood that the term locking mechanism may, in some circumstances, also be interpreted to include the shape control portion and one or more distal structures secured to the distal end of the shape control portion and in contact with / engage with an engagement member.

[0103] Although the present invention has been described in the context of particular embodiments and applications, those skilled in the art can, in light of the present teachings, create additional embodiments and modifications without departing from the principles of the present invention as set forth in the claims or beyond its scope. Accordingly, the drawings and descriptions herein are provided by way of example to facilitate understanding of the present invention and should not be construed as limiting the scope of the present invention.

Claims

1. An obstruction removal device (800, 801, 803) comprising: a pusher (806) having a pusher lumen; at least one engaging member (802a, 802b, 802c, 802d), the most proximal engaging member of the at least one engaging member being coupled to the distal end of the pusher; an elongate element (808) positioned within the pusher lumen; at least one locking mechanism (804 or 812) disposed within the body of the at least one engagement member (802a, 802b, 802c, 802d); Including, In a first configuration, the elongate element is in a first position and the at least one engagement member is in a radially collapsed configuration; In a second configuration, the elongate element is in a second position different from the first position, the at least one locking mechanism prevents the elongate element from moving further distally from the second position relative to the pusher, and the at least one engaging member is in a radially expanded shape. Obstruction removal device.

2. The obstruction removal device of claim 1 , wherein the at least one engaging member comprises a plurality of posts defining multiple openings.

3. The obstruction removal device of claim 2 , wherein the locking mechanism includes at least one star-shaped retaining member (812) secured to the elongate element.

4. 2. The obstruction removal device of claim 1, wherein said elongate element extends from said pusher to a distal-most one of said at least one engaging member.

5. 5. The obstruction removal device of claim 4, wherein a proximal end of the elongate element extends beyond a proximal end of the pusher, the proximal end of the elongate element being configured to be pulled or pushed by a user.

6. further comprising a distal cap connected to a distal end of the elongate element; 5. The obstruction removal device of claim 4, wherein the distal cap is a distal cap having a diameter greater than the distal opening of the distal-most one of the at least one engaging member.

7. The obstruction removal device of claim 1 , wherein the locking mechanism comprises a fastener secured to the elongate element.

8. 10. The obstruction removal device of claim 1, further comprising a collet disposed near a proximal end of the pusher and configured for selective engagement with the elongate element to prevent movement of the elongate element relative to the pusher.

9. The obstruction removal device of claim 1 , wherein the at least one engaging member comprises a plurality of engaging members.

10. In the first configuration, each of the plurality of engagement members has a radially crushed shape; 10. The obstruction removal device of claim 9, wherein in said second configuration, each of said plurality of engaging members is in a radially expanded shape.

11. The obstruction removal device of claim 9 , wherein each of the plurality of engaging members has a plurality of posts defining a number of apertures.

12. 10. The obstruction removal device of claim 1, wherein the elongate element is longitudinally movable relative to the pusher to move the obstruction removal device between the first configuration and the second configuration.

13. In the first configuration, a portion of the elongate element is at a third position within the pusher lumen; The obstruction removal device of claim 1 , wherein in the second configuration, the portion of the elongate element is at a fourth position within the pusher lumen.

14. 2. The obstruction removal device of claim 1, wherein the elongate element has at least one extension and the pusher has a channel, and in the second configuration, the at least one extension is within the channel and in the first configuration, the at least one extension is not within the channel.

Images