Proximal Lock Assembly Design for a Dual Stent Mechanical Thrombectomy Device

Abstract

To provide a proximal mechanical locking assembly.SOLUTION: A mechanical locking assembly for an endovascular device comprises a shaft 100 comprising a main body 110 and an enlarged end 112, an inner channel component 118 comprising a full collar 122 formed on a proximal end of the inner channel component, and an outer cage component 130 comprising a partial collar 132 formed on the outer cage component, where the full collar of the inner channel component fully surrounds the outer cage component, and the partial collar of the outer cage component at least partially surrounds the shaft.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure generally relates to intravascular devices and methods, and more specifically to forming a proximal mechanical lock assembly on a dual stent mechanical thrombus removal device. The present disclosure also relates to an intravascular joint assembly that can be used as a component of an intravascular device for removing vascular occlusions.

Background Art

[0002] Recent clinical studies have shown that mechanical thrombectomy is an increasingly effective method for removing acute occlusions from blood vessels. Acute occlusions can include blood clots, mispositioned devices, displaced devices, large emboli, and the like. Ischemic stroke can result when an occlusion clogs the cerebral vasculature. Pulmonary embolism can result when an occlusion such as a blood clot occurs in the venous system or on the right side of the heart and lodges in the pulmonary artery or its branches. Mechanical thrombectomy typically involves advancing a thrombus removal device or stentriever to the occlusive blood clot location, engaging the blood clot, and retracting the blood clot into the safety device of a guide or sheath positioned proximally.

[0003] However, while there are benefits provided by mechanical thrombectomy devices, there are limitations. For example, there are numerous procedural challenges that can cause excessive tension or compression on the device components. When access involves navigating the aortic arch (such as in coronary artery occlusion or cerebral occlusion), the configuration of the aortic arch in some patients makes it difficult to position the stentriever. These difficult aortic arch configurations are classified as type II or type III aortic arches, with type III aortic arches presenting the greatest obstacle. The problem of tortuosity is even more severe in arteries approaching the brain. For example, it is not uncommon at the distal end of the internal carotid artery for the device to have to continuously progress over a few centimeters of blood vessel with vascular segments having 180° bends, 90° bends, and 360° bends. By delivering the device to the target location through a tortuous anatomical structure, there is a possibility of compressive loads being applied to the joints between the device components and between the distal portion and the shaft. Further, due to the displacement force of the occlusive material within the blood vessel and retrieval through the tortuosity of the vasculature, there is a possibility of large tensile loads being applied to the joints. When retrieving the occlusive material into the access catheter, there is also a possibility of large forces being applied to the proximal joints of the device components and the shaft.

[0004] These intravascular devices can often be integrally formed with a joint assembly that connects the clot-engaging portion to an elongate shaft. These assemblies can rely on adhesive bonding, welding, or soldering. The adhesive can be applied to ensure that the components maintain their correct position and orientation, but in some cases, it may be desirable to enhance the bonding strength and integrity.

[0005] Furthermore, as shown in FIG. 1, the current proximal mechanical coupling on the dual stent mechanical thrombectomy device generally includes a stepped nitinol shaft 10, an outer cage component 30 having a full cylindrical proximal collar 32, and an inner channel component 20 having a partial C-shaped collar. These three components are assembled such that a mechanical lock is formed so that these components cannot be separated under tension without material deformation or breakage. However, in order to maintain an appropriate cross-sectional profile (and to maintain 0.021-inch or 0.017-inch microcatheter compatibility), the design of the outer cage collar component requires that the nitinol tube raw material used to form this component have a maximum outer diameter that is smaller than the inner diameter of the microcatheter. Forming a similar proximal mechanical lock would be problematic if a larger diameter nitinol tube raw material were specified for the outer cage component. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] Accordingly, there is a need for an intravascular device having a proximal connector that is compatible with raw material tubes of various sizes and has sufficient integrity to effectively capture occlusions for safe retrieval from a patient. MEANS FOR SOLVING THE PROBLEMS

[0007] This specification discloses various exemplary intravascular devices of the present disclosure that can address the above needs. The device can generally be a joint assembly that includes a shaft, an outer cage component including an outer cage collar and an outer cage proximal strut, and an inner channel component including an inner channel collar and an inner channel proximal strut. The joint assembly can be integrally joined to the intravascular device between the clot engaging portion and the elongate shaft. In this way, the joint assembly enables the capture of occlusions by the clot engaging portion of the intravascular device having increased load support provided by the joint assembly. In another example, the joint assembly of a dual stent thrombus removal device has an inner channel component and an outer cage component including a proximal mechanical lock, a shaft including a body and an enlarged end, a full collar formed on the inner channel component, and a partial collar formed on the outer cage component. The partial collar of the outer cage component can at least partially surround the shaft, and the full collar of the inner channel component can fully surround the partial collar of the outer cage component.

[0008] In another example, the joint assembly includes a joint assembly for an intravascular device and has a shaft including a body and an enlarged end, a proximal strut including strut slots and at least one strut slit, and a lock collar having a distal surface and at least one collar pin protruding from the lock collar near the distal surface of the collar, wherein the strut slots engage the enlarged end of the shaft and the proximal strut is configured such that the strut slit bends to lock and engage at least one collar pin.

[0009] In one example, a joint assembly for an intravascular device can include a shaft having a body and an enlarged end portion, a lock collar, a first proximal strut including a first slot, and a second proximal strut including a second slot, each of the first and second slots engaging the enlarged end portion of the shaft, and the lock collar at least partially covering the enlarged end portion of the shaft, the first and second slots of the first and second proximal struts. In some embodiments, at least a portion of this enlarged end portion is received within both of the proximal strut slots. In some embodiments, this enlarged end portion of the shaft defines a shaft step together with the body of the shaft. In some embodiments, the lock collar restrains the first proximal strut and the second proximal strut such that the first strut slot and the second strut slot cannot disengage from the enlarged end portion of the shaft when the joint assembly is under a compressive or tensile load.

Brief Description of the Drawings

[0010] The foregoing and further aspects of the present disclosure will be further considered with reference to the following description in conjunction with the accompanying drawings, in which like numerals in the various drawings indicate like structural elements and features. The drawings are not necessarily to scale, and instead, emphasis is placed on illustrating the principles of the present disclosure. The figures depict one or more implementations of the apparatus of the present invention by way of example and not limitation.

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DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific embodiments of the present disclosure are hereinafter described in detail with reference to the drawings, and the same reference numerals indicate the same or functionally similar elements. The terms "distal" or "proximal" are used in the following description with respect to the position or direction relative to the treating physician. "Distal" or "distally" means a position away from the physician or a direction away from the physician. "Proximal" or "proximally" or "adjacent" means a position close to the physician or a direction towards the physician.

[0012] The term "about" or "approximately" used herein for any numerical value or range of numerical values indicates an acceptable tolerance of suitable dimensions that enables a part of a component or a set of components to function in accordance with its intended purpose described herein. More specifically, "about" or "approximately" can refer to a range of values of ±20% of the recited value. For example, "about 90%" can refer to a range of values from 71% to 99%.

[0013] Accessing the brain, coronary arteries, and pulmonary veins involves the use of a number of commercially available products and conventional treatment procedures. Access products such as stent retrievers and thrombus removal devices are described elsewhere and are commonly used in endovascular procedures. For example, see U.S. Patent Publication No. 2015 / 0164523, which is hereby incorporated by reference in its entirety as if fully set forth herein. In the following description, these products and methods are assumed to be used in conjunction with the devices and methods of the present disclosure and need not necessarily be described in detail.

[0014] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure, or the application or use of the present disclosure. The description of the present disclosure is often in the context of treating vascular occlusions, but the present disclosure may also be used in other body passages as described herein.

[0015] As shown in FIG. 2, an example of a joint assembly can include a shaft 100, an inner channel component 118 including a full-color 122 formed on a proximal end of the inner channel component 118, and an outer cage component 130 including a partial-color 132 formed on the outer cage component 130. The shaft 100 can include a body 110 and an enlarged end 112. In some embodiments, the full-color 122 of the inner channel component 118 can completely surround the partial-color 132 of the outer cage component 130. The partial-color 132 of the outer cage component 130 can at least partially surround the shaft 100. In some examples, the partial-color 132 of the outer cage component 130 can have a C-shaped cross-section over at least a portion of its length, such that the partial-color only partially surrounds a portion of the shaft with the partial-color 132 having a C-shaped cross-section. In some examples, the outer cage component and the inner channel component can each include integrally joined proximal struts, respectively. The diameter of the color 122 of the inner channel component 118 can range from about 0.021 inches to about 2 inches (e.g., 0.025 inches, 0.030 inches, 0.075 inches, 0.15 inches, 0.45 inches, 0.1 inches, 0.5 inches, 0.8 inches, 1.5 inches, 1.75 inches). Similarly, the diameter of the color 132 of the outer cage component 130 can range from about 0.001 inches to about 0.021 inches (e.g., 0.019 inches, 0.017 inches, 0.015 inches, 0.013 inches, 0.011 inches, 0.009 inches, 0.007 inches, 0.005 inches, 0.003 inches, 0.001 inches). The diameter of the color 132 of the outer cage component 130 can be measured based on the outer perimeter of a circle including the arc of the C-shaped color 132.

[0016] As shown in FIG. 3, a previously disclosed joint assembly can include a shaft 40 including a body 42 and an enlarged step 44, a proximal strut 48 engaged with the shaft 40, and a lock collar 46 that receivably engages at least a portion of the body 42 and at least a portion of the proximal strut 48 to lock the assembly in a predetermined position. The joint assembly can further include a proximal strut slot 49. Excessive tension can cause sufficient tensile stress on the shaft to disengage the proximal strut from the enlarged step of the shaft, thereby deforming the enlarged end portion. As a result, during removal of an occlusion or when pulled proximally around a bend in a tortuous blood vessel, the joint device of a stent delivery or thrombus removal device may become disengaged or may allow a captured blood clot to escape.

[0017] FIGS. 4-5 illustrate an alternative joint assembly embodiment according to the present disclosure. This joint assembly can include a shaft 200 having a body 210 and an enlarged end 212. In this embodiment, inner channel components such as an inner channel collar 230 and a proximal strut 218 are integrally joined to each other, and the inner channel collar 230 is attached to an outer cage proximal strut 220 by any suitable means. The outer cage proximal strut 220 may be on the distal side of the shaft 200 and at the proximal end of the stent delivery. The inner channel collar 230 can have the same diameter as the raw material tubing from which it is cut. This eliminates the need for separate outer cage and inner channel components to achieve mechanical locking between components within the assembly. In some embodiments, the outer cage proximal strut 220 can engage the inner channel collar 230 such that the inner channel collar 230, the shaft 200, and the outer cage proximal strut 220 are locked and engaged by a friction fit. The friction fit engagement can prevent the outer cage proximal strut 220 from disengaging from the enlarged end 212 of the shaft 200 when the joint assembly is integrally formed within an intravascular device and the intravascular device is under load.

[0018] The proximal strut 220 of the outer cage 220 can further include a strut slot 222 having an opening in which a portion of the enlarged end 212 of the shaft 200 can be positioned. When the enlarged end 212 of the shaft 200 is positioned within the slot 222 of the proximal strut 220 of the outer cage, the inner channel collar 230 is positioned to at least partially surround the enlarged end 212 of the shaft 200 and the slot 222 of the proximal strut 220 of the outer cage, and can effectively fix the enlarged end 212 within the slot 222.

[0019] As shown in FIG. 6, an exemplary joint assembly can include a shaft 300, a first proximal strut 320, a lock collar 330, and a second proximal strut 340. The first and second proximal struts 320, 340 are on the distal side of the shaft 300 but at the proximal end of the stent delivery device. In some embodiments, the shaft 300 can include a body 310 and an enlarged end 312. The enlarged end 312 can include an upper end 314 and a lower end 316. In some embodiments, the first proximal strut 320 can include a first strut slot 322. In some embodiments, the second proximal strut 340 can include a second strut slot 342. In some embodiments, the first slot 322 can engage the upper end 314 of the enlarged end 112 of the shaft 100. As shown in FIG. 7, the second slot 342 can engage the lower end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the lock collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first strut slot 322 of the first proximal strut 320, and the second strut slot 342 of the second proximal strut 340. In some embodiments, at least a portion of the enlarged end 112 is received within the first proximal strut slot 322, within the second strut slot 342 of the second proximal strut 340, or within both the first slot 322 and the second slot 342. In some embodiments, the enlarged end 312 of the shaft 300 defines a shaft step 313 with the body 310 of the shaft 300. In some embodiments, the proximal strut further includes a tail 324.

[0020] As shown in FIG. 8, in some embodiments, an exemplary joint assembly can include a shaft 400, a proximal strut 420, and a lock collar 430. The proximal strut 420 is distal to the shaft 400 but proximal to the proximal end of the stent delivery. In some embodiments, the shaft 400 can include a body 410 and an enlarged end 412. In some embodiments, as shown in FIG. 9, the proximal strut 420 can include a slot 422 and / or a strut slit 424. In some embodiments, the slot 422 can engage the enlarged end 412 of the shaft 400. As shown in FIG. 10, the lock collar 430 can include a distal surface 434 and a collar pin 432 near the distal surface of the lock collar 430. FIG. 11 shows that when the shaft 400 is pulled inside the lock collar 430, the collar pin 432 can lock into the strut slit 424 of the proximal strut 420, forming a mechanical lock. The proximal strut 420 can include a flexible material, such that it can bend to allow the strut slit 424 to engage the collar pin 432. In this proposed design, the collar will be locked in place, and this mechanical lock will add the tensile strength of the overlay for advancement and retrieval, and the use of a UV adhesive may no longer be necessary. During assembly, the operator simply needs to place the proximal strut 420 on the enlarged end 412 of the shaft 400 and pull both through the lock collar 430, and the flexible nitinol strut will lock into place with the collar pin 432. The lock collar 430 constrains the proximal strut slot 422 against the enlarged end 412, such that the proximal strut slot 422 maintains engagement with the enlarged end 412 under a tensile load up to a force of about 2N to 15N (e.g., 3N, 4N, 5N, 6N, 7N, 8N, 9N, 10N, 11N, 12N, 13N, 14N).

[0021] In some embodiments, the coupling assembly can be of any suitable size and shape that is compatible with a microcatheter used for neurovascular device delivery. The proximal strut slot can be of any suitable shape for engaging the enlarged end. For example, suitable shapes for the proximal strut slot can include substantially square, substantially rectangular, substantially circular, and the like. Both the inner channel component and the outer cage component can be of any suitable shape for covering or sealing at least a portion of the proximal strut slot and the enlarged end of the shaft. Suitable shapes for the outer cage component can include substantially partially cylindrical, substantially partially elliptical cylindrical, and the like. Suitable shapes for the inner channel component can include substantially cylindrical, substantially elliptical cylindrical, and the like. The body and the enlarged end of the shaft can be of any suitable size and shape for engaging the proximal strut and for being at least partially received within the inner channel component and the outer cage component. Suitable shapes for the body can include substantially cylindrical, substantially elliptical cylindrical, and the like. Suitable shapes for the enlarged end can include substantially cylindrical, substantially elliptical cylindrical, and the like. In some embodiments, the coupling assembly can be sized to be compatible with a microcatheter having an inner diameter of 0.027 inches or less (e.g., 0.026 inches, 0.024 inches, 0.022 inches, 0.019 inches, 0.017 inches, 0.015 inches, 0.013 inches, 0.011 inches, 0.009 inches, 0.007 inches, 0.005 inches, 0.003 inches, 0.001 inches), preferably 0.021 inches or less (e.g., 0.019 inches, 0.017 inches, 0.015 inches, 0.013 inches, 0.011 inches, 0.009 inches, 0.007 inches, 0.005 inches, 0.003 inches, 0.001 inches).

[0022] Suitable materials for forming the shaft, proximal strut, and collar preferably have a high tensile strength such that they can create sufficient integrity for manufacturability and use, such as, for example, polymeric materials such as UHMWPE, aramid, LCP, PET, or PEN, or metals such as tungsten, MP35N, stainless steel, or nitinol. The proximal strut slot can be of any suitable shape for engaging the enlarged end.

[0023] In some embodiments, any of the above-described joint assemblies can be integrally joined to an intravascular device between the blood clot engaging portion and the elongate shaft. Examples of intravascular devices can include stent retrievers, thrombus removal devices, coil retrievers, equivalents now known or later discovered, or combinations thereof.

[0024] The descriptions contained herein are examples of embodiments of the present disclosure and are not intended to limit the scope of the present disclosure in any way. As described herein, the present disclosure contemplates numerous variations and modifications of the joint assembly, such as, for example, various positionings of the shaft, proximal strut, and collar, the use of any of a number of materials for each element or member, and the incorporation of additional elements or members. These modifications will be apparent to those skilled in the art to which the present disclosure pertains and are intended to be within the scope of the following claims.

[0025] 〔Embodiments〕 (1) A proximal mechanical lock assembly for a thrombus removal device, a shaft including a body and an enlarged end, an inner channel component including a full collar formed on the proximal end of the inner channel component, an outer cage component including a partial collar formed on the outer cage component, and A proximal mechanical lock assembly in which the partial color of the outer cage component at least partially surrounds the shaft and the full color of the inner channel component fully surrounds the partial color of the outer cage component. (2) The proximal mechanical lock assembly according to embodiment 1, wherein the enlarged end portion of the shaft defines a shaft step together with the body of the shaft. (3) The proximal mechanical lock assembly according to embodiment 1, wherein the full color of the inner channel component is substantially cylindrical. (4) The proximal mechanical lock assembly according to embodiment 1, wherein the partial color of the outer cage component is C-shaped. (5) The proximal mechanical lock assembly according to embodiment 1, wherein the diameter of the outer cage component is from about 0.533 mm to about 50.8 mm (about 0.021 inches to about 2 inches).

[0026] (6) The proximal mechanical lock assembly according to embodiment 1, wherein the diameter of the inner channel component is from about 0.025 mm to about 0.533 mm (about 0.001 inches to about 0.021 inches). (7) A method of forming a proximal mechanical lock assembly for a thrombus removal device, providing a shaft including a body, an inner channel component including a full color formed on a proximal end portion of the inner channel component, and an outer cage component including a partial color formed on the outer cage component, positioning the outer cage component at least partially around the shaft, positioning the inner channel component at least partially around the outer cage component, such that the shaft, the inner channel component, and the outer cage component are mechanically locked. (8) The method according to embodiment 7, wherein the shaft further includes an enlarged end portion. (9) The method according to embodiment 7, wherein the enlarged end portion of the shaft defines a shaft step together with the body of the shaft. (10) The method according to embodiment 9, wherein the overall color of the inner channel component is substantially cylindrical.

[0027] (11) The method according to embodiment 7, wherein the partial color of the outer cage component is C-shaped. (12) The method according to embodiment 7, wherein the diameter of the outer cage component is from about 0.533 mm to about 50.8 mm (about 0.021 inches to about 2 inches). (13) The method according to embodiment 7, wherein the diameter of the inner channel component is from about 0.025 mm to about 0.533 mm (about 0.001 inches to about 0.021 inches). (14) A proximal mechanical lock assembly for a thrombus removal device, a shaft including a body and an enlarged end portion, an inner channel component including a proximal collar, an outer cage component including a proximal strut, the proximal strut including a slot opening therethrough, wherein the enlarged end portion is positioned within the slot opening of the outer cage component, and the proximal collar of the inner channel component at least partially surrounds the enlarged end portion and the slot opening. (15) The proximal mechanical lock assembly according to embodiment 14, wherein the inner channel component is curved.

[0028] (16) A coupling assembly for an intravascular device, a shaft including a body and an enlarged end portion, the enlarged end portion having an upper end portion and a lower end portion, a first proximal strut including a first slot, the first slot engaging the upper end portion of the enlarged end portion of the shaft, A second proximal strut including a second slot, the second slot engaging with a lower end portion of the enlarged end portion of the shaft, the second proximal strut; A joint assembly comprising the enlarged end portion of the shaft, the first slot of the first proximal strut, and a lock collar at least partially covering the second slot of the second proximal strut. (17) The joint assembly according to embodiment 16, wherein at least a portion of the enlarged end portion is received within both the first strut slot and the second strut slot. (18) The joint assembly according to embodiment 16, wherein the collar restrains the first proximal strut and the second proximal strut such that the first strut slot and the second strut slot cannot disengage from the enlarged end portion of the shaft when the joint assembly is attached to a blood clot retrieval device and the blood clot retrieval device is under load. (19) A joint assembly for an intravascular device, A shaft including a body and an enlarged end portion, A proximal strut including a strut slot and at least one strut slit, A lock collar having a distal surface and at least one collar pin protruding from the lock collar near the distal surface of the collar, The strut slot engages with the enlarged end portion of the shaft, The proximal strut is configured to bend to allow the strut slit to lock and engage with the at least one collar pin. A joint assembly. (20) The joint assembly according to embodiment 19, wherein the proximal strut includes a flexible material.

Claims

**Claim 1** A proximal mechanical lock assembly for a thrombus removal device, comprising a shaft including a body and an enlarged end, an inner channel component including a full-color collar formed on a proximal end of the inner channel component, an outer cage component including a partial-color collar formed on the outer cage component, wherein the partial-color collar of the outer cage component at least partially surrounds the shaft, and the full-color collar of the inner channel component fully surrounds the partial-color collar of the outer cage component, the proximal mechanical lock assembly further comprising a proximal strut integrally joined to the outer cage component, a proximal strut integrally joined to the inner channel component, wherein the proximal strut integrally joined to the outer cage component extends outwardly beyond the proximal strut integrally joined to the inner channel component, and the outer side is farther from the longitudinal axis than the inner side in a plane perpendicular to the longitudinal axis of the shaft. **Claim 2** The proximal mechanical lock assembly according to claim 1, wherein the enlarged end of the shaft defines a shaft step together with the body of the shaft. **Claim 3** The proximal mechanical lock assembly according to claim 1, wherein the full-color collar of the inner channel component is cylindrical. **Claim 4** The proximal mechanical lock assembly according to claim 1, wherein the partial-color collar of the outer cage component is C-shaped in a cross-section perpendicular to the longitudinal axis of the shaft. **Claim 5** The proximal mechanical lock assembly according to claim 1, wherein the diameter of the outer cage component is from 0.533 mm to 50.8 mm (0.021 inch to 2 inches). **Claim 6** The proximal mechanical lock assembly according to claim 1, wherein the diameter of the inner channel component is from 0.025 mm to 0.533 mm (0.001 inch to 0.021 inch). **Claim 7** The proximal mechanical lock assembly according to claim 1, wherein the diameter of the inner channel component is from 0.533 mm to 50.8 mm (0.021 inch to 2 inches), and the diameter of the outer cage component is from 0.025 mm to 0.533 mm (0.001 inch to 0.021 inch). **Claim 8** The proximal mechanical lock assembly according to claim 1, integrally joined to the thrombus removal device.

9. The proximal strut integrally joined to the outer cage component extends distally from the distal end of the partial collar of the outer cage component, and the proximal strut integrally joined to the inner channel component extends distally from the distal end of the full collar of the inner channel component. The proximal mechanical lock assembly according to claim 1.

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