Proximal locking assembly design for dual stent mechanical thrombectomy device

Abstract

A mechanical locking assembly for an intravascular device is provided, comprising a shaft comprising a main body and an enlarged end portion, an inner channel component comprising a full collar formed on a proximal end of the inner channel component, and an outer cage component comprising a partial collar formed on the outer cage component, wherein the full collar of the inner channel component completely surrounds the outer cage component, and the partial collar of the outer cage component at least partially surrounds the shaft.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to intravascular devices and methods, and more particularly to forming a proximal mechanical locking assembly on a dual stent mechanical thrombectomy device. The invention similarly relates to intravascular junction assemblies that can be used as components of intravascular devices for removing vascular emboli. BACKGROUND

[0002] Recent clinical studies have shown that mechanical thrombectomy is an increasingly effective method for removing acute emboli from blood vessels. Acute emboli can include clots, malpositioned devices, migrated devices, large emboli, and the like. If the emboli are retained in the cerebral vasculature, it can result in ischemic stroke. If the emboli, such as a clot, originates from the venous system or the right side of the heart and is retained in the pulmonary artery or its branches, it can result in pulmonary embolism. Mechanical thrombectomy generally involves advancing a thrombectomy device or stent into the obstructing clot, engaging the clot, and withdrawing the clot into a safe position in a guide or sheath placed proximally.

[0003] However, despite the beneficial effects of mechanical thrombectomy devices, there are limitations. For example, there are many procedural challenges that can exert excessive tension or compression on the device components. In cases involving navigation of the aortic arch, such as coronary or cerebral blockages, the arch configuration of some patients makes it difficult to position the stent. These difficult arch configurations are classified as type 2 or type 3 aortic arches, with type 3 arches presenting the most difficulty. In the arteries approaching the brain, the tortuosity challenges are even more severe. For example, at the distal end of the internal carotid artery, the device will have to navigate through several centimeters of vessel with a 180° bend, a 90° bend, and a 360° bend in rapid succession, which is not uncommon. Delivering the device through the curved anatomy to the target location can exert compression loads on the device components as well as the junction between the distal segment and the shaft. In addition, the dislodging force of the emboli in the vessel and the withdrawal through the tortuous vasculature can exert high tension loads on the junction. The withdrawal of the emboli into the access catheter also exerts a great force on the proximal junction of the device components and shaft.

[0004] These intravascular devices can be integrally formed with a junction assembly that generally connects the clot engaging portion to the elongated shaft. These assemblies can rely on adhesive bonding, welded bonding, or brazing. Adhesives can be applied to ensure that the components remain in the correct position and orientation, but increased bonding strength and integrity can be needed in some cases.

[0005] Furthermore, as Figure 1As shown in the middle, the current proximal mechanical bond on a dual stent mechanical thrombectomy device typically includes a stepped nitinol shaft 10, an outer cage component 30 with a full cylindrical proximal collar 32, and an inner channel component 20 with a partial C-shaped collar. The three components are assembled such that a mechanical lock is formed so that the components cannot separate under tension without material deformation or failure. However, in order to maintain a proper cross profile (and maintain 0.021" or 0.017" microcatheter compatibility), the design of the outer cage collar component requires that the nitinol tubing stock used to form the component have a maximum outer diameter that is less than the inner diameter of the microcatheter. If a larger diameter nitinol tube stock is specified for the outer cage component, forming a similar proximal mechanical lock is problematic.

[0006] Accordingly, there is a need for an endovascular device having a proximal joint that is compatible with different sized stock tubing, that has sufficient integrity to effectively capture emboli for safe retrieval from a patient. SUMMARY

[0007] Various exemplary endovascular devices of the present disclosure that can address the needs described above are disclosed herein. The devices can be a joint assembly that can generally include 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 an endovascular device between a clot engaging portion and an elongate shaft. As such, the joint assembly allows for emboli capture by the clot engaging portion of the endovascular device while providing increased load support by the joint assembly. In another example, a joint assembly of a dual stent thrombectomy device has an inner channel component and an outer cage component including a proximal mechanical lock, with a shaft including a body and an enlarged end portion, 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 completely surround the partial collar of the outer cage component.

[0008] In another example, a joint assembly for an endovascular device includes a shaft including a body and an enlarged end portion, a proximal strut including a strut slot and at least one strut slit, and a locking collar having a distal face and at least one collar pin protruding from the locking collar proximate the distal face of the collar, wherein the strut slot engages the enlarged end portion of the shaft, and wherein the proximal strut is configured to allow the strut slit to flex to lockingly engage the 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, a locking collar, a first proximal strut including a first slot, and a second proximal strut including a second slot, wherein each of the first and second slots engage the enlarged end of the shaft, and wherein the locking collar at least partially covers the enlarged end of the shaft and the first and second slots of the first and second proximal struts. In some embodiments, at least a portion of the enlarged end is received in both proximal strut slots. In some embodiments, the enlarged end of the shaft defines a shaft step with the body of the shaft. In some embodiments, the locking collar constrains the first and second proximal struts such that the first and second strut slots cannot disengage the enlarged end of the shaft when the joint assembly is under compression or tensile load. BRIEF DESCRIPTION OF DRAWINGS

[0010] The above aspects and additional aspects of the present disclosure will be further discussed with reference to the following description and drawings,

[0011] In the drawings, like numbers refer to like elements throughout. The drawings, which are not necessarily to scale, depict one or more embodiment(s) of the application. The embodiments presented are by way of example only and are not intended to limit the scope of the invention.

[0012] Figure 1 A configuration of an example prior art mechanical locking assembly is shown;

[0013] Figure 2 A perspective view of an example mechanical locking assembly of the present disclosure is shown;

[0014] Figure 3 A configuration of an example prior art joint assembly is shown;

[0015] Figure 4 A configuration of an example joint assembly of the present disclosure is shown;

[0016] Figure 5 A side view of a locking collar of an example joint assembly according to the present disclosure is shown;

[0017] Figure 6 A configuration of an example joint assembly of the present disclosure is shown;

[0018] Figure 7 An alternative configuration of an example joint assembly of the present disclosure is shown;

[0019] Figure 8 A side view of an example joint assembly of the present disclosure is shown;

[0020] Figure 9 A top view of an example joint assembly of the present disclosure is shown;

[0021] Figure 10 A side view of a locking collar of an example joint assembly according to the present disclosure is shown; and

[0022] Figure 11 A side view of an alternative configuration of an example joint assembly of the present disclosure is shown. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to specific implementations of the present disclosure, one or more examples of which are illustrated in the figures. The same or like elements are referred to with the same or like reference numbers. The terms "distal" or "proximal" are used in the following description with respect to the position or orientation relative to the treating physician. "Distal" or "distally" is the position away from the physician or in the direction away from the physician. "Proximal" or "proximally" or "proximate" is the position close to the physician or in the direction toward the physician.

[0024] As used herein, the term "about" or "approximately" with reference to any numerical or range of values indicates suitable dimensional tolerances that allow the components or elements to function for their intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of values ±20% of the recited value, for example "about 90%" can refer to a range of values from 71% to 99%.

[0025] Access to cerebral, coronary, and pulmonary vessels involves the use of a number of commercially available products and routine procedural steps. Access products such as stents and thrombectomy devices are described elsewhere and are frequently used in intravascular procedures. See, e.g., U.S. Patent Publication 2015 / 0164523, which is hereby incorporated by reference in its entirety as if fully set forth herein. These products and methods are assumed to be used in conjunction with the devices and methods of the present disclosure in the following description and do not need to be described in detail.

[0026] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Although the description of the present disclosure is in many instances presented in the context of treating vascular blockages, the present disclosure can also be used in other body passageways as described herein.

[0027] As Figure 2As shown, an example of a connector assembly may have a shaft 100, an inner channel component 118, and an outer retainer component 130. The inner channel component includes a full bushing 122 formed on a proximal end of the inner channel component 118, and the outer retainer component includes a partial bushing 132 formed on the outer retainer component 130. The shaft 100 may include a body 110 and an enlarged end 112. In some embodiments, the full bushing 122 of the inner channel component 118 may completely surround the partial bushing 132 of the outer retainer component 130. The partial bushing 132 of the outer retainer component 130 may at least partially surround the shaft 100. In some examples, the cross-section of the partial bushing 132 of the outer retainer component 130 may be C-shaped over at least a portion of its length, such that the partial bushing only partially surrounds the shaft in the portion of the partial bushing 132 having a C-shaped cross-section. In some examples, the outer retainer component and the inner channel component may each each include an integrally joined proximal strut. The diameter of the bushing 122 of the internal 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 bushing 132 of the external retainer 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 bushing 132 of the external retainer component 130 can be measured based on the outer perimeter of a circle that includes the arc of the C-shaped bushing 132.

[0028] like Figure 3 As shown, the previously disclosed connector assembly may include: a shaft 40, a proximal strut 48, and a locking bushing 46. The shaft includes a body 42 and an enlarging step 44. The proximal strut engages with the shaft 40, and the locking bushing engageably receives at least a portion of the body 42 and at least a portion of the proximal strut 48 to lock the assembly in place. It may also include a proximal strut slot 49. Excessive tension can induce sufficient tensile stress on the shaft to disengage the proximal strut from the enlarging step of the shaft, thereby deforming the enlarged end. This may cause the connector assembly of the stent or thrombectomy device to disassemble during embolization or when the curved portion retracts proximally around a tortuous vessel, or to capture potential clot escape.

[0029] Figures 4-5An alternative embodiment of the connector assembly according to this disclosure is shown. The connector assembly may include a shaft 200 having a body 210 and an enlarged end 212. In this embodiment, an inner channel bushing 230 and inner channel components such as a proximal support 218 are integrally engaged with each other, and the inner channel bushing 230 is attached to an outer retainer proximal support 220 by any suitable means. The outer retainer proximal support 220 may be located distal to the shaft 200 and at the proximal end of the support. The inner channel bushing 230 may have the same diameter as the raw material tube from which the inner channel bushing is cut. This eliminates the need for separate outer retainers and inner channel components to achieve mechanical locking between components in the assembly. In some embodiments, the outer retainer proximal support 220 may engage the inner channel bushing 230 such that the inner channel bushing 230, the shaft 200, and the outer retainer proximal support 220 are locked together by a friction fit. When the connector assembly is integrally formed into the intravascular device and the intravascular device is under load, the frictional engagement prevents the proximal support bar 220 of the external retainer from disengaging from the enlarged end 212 of the shaft 200.

[0030] The proximal strut 220 of the outer retainer 220 may also include a strut slot 222 with an opening in which a portion of the enlarged end 212 of the shaft 200 may be positioned. When the enlarged end 212 of the shaft 200 is positioned in the slot 222 of the proximal strut 220 of the outer retainer, the inner channel bushing 230 may be positioned at least partially around the enlarged end 212 of the shaft 200 and the slot 222 of the proximal strut 220 of the outer retainer to effectively secure the enlarged end 212 within the slot 222.

[0031] like Figure 6 As shown, an exemplary connector assembly may include a shaft 300, a first proximal support 320, a locking bushing 330, and a second proximal support 340. The first proximal support 320 and the second proximal support 340 are located distal to the shaft 300 but at the proximal end of the support. In some embodiments, the shaft 300 may include a body 310 and an enlarged end 312. The enlarged end 312 may include a top end 314 and a bottom end 316. In some embodiments, the first proximal support 320 may include a first support slot 322. In some embodiments, the second proximal support 340 may include a second support slot 342. In some embodiments, the first slot 322 may engage the top end 314 of the enlarged end 112 of the shaft 100. Figure 7As shown in FIG. 34, the second slot 342 can engage the bottom end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the locking collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first 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 in the first proximal strut slot 322, the second proximal strut slot 342 of the second proximal strut 340, or 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 comprises a tail 324.

[0032] As shown in FIG. 34, the second slot 342 can engage the bottom end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the locking collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first 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 in the first proximal strut slot 322, the second proximal strut slot 342 of the second proximal strut 340, or 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 comprises a tail 324. Figure 8 As shown in FIG. 34, the second slot 342 can engage the bottom end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the locking collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first 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 in the first proximal strut slot 322, the second proximal strut slot 342 of the second proximal strut 340, or 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 comprises a tail 324. Figure 9 As shown in FIG. 34, the second slot 342 can engage the bottom end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the locking collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first 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 in the first proximal strut slot 322, the second proximal strut slot 342 of the second proximal strut 340, or 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 comprises a tail 324. Figure 10 As shown in FIG. 34, the second slot 342 can engage the bottom end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the locking collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first 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 in the first proximal strut slot 322, the second proximal strut slot 342 of the second proximal strut 340, or 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 comprises a tail 324. Figure 11 As shown in FIG. 34, the second slot 342 can engage the bottom end 316 of the enlarged end 312 of the shaft 300. In some embodiments, the locking collar 330 can at least partially cover the enlarged end 312 of the shaft 300, the first 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 in the first proximal strut slot 322, the second proximal strut slot 342 of the second proximal strut 340, or 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 comprises a tail 324.

[0033] In some embodiments, the junction assembly can be any suitable size and shape to be compatible with a microcatheter for neurovascular device delivery. The proximal strut slot can be any suitable shape for engaging the enlarged end portion. For example, suitable shapes for the proximal strut slot can include a generally square shape, a generally rectangular shape, a generally circular shape, etc. Both the inner channel component and the outer cage component can be any suitable shape for covering or encasing at least a portion of the proximal strut slot and the enlarged end portion of the shaft. Suitable shapes for the outer cage component can include a generally partial cylindrical shape, a generally partial elliptical cylindrical shape, etc. Suitable shapes for the inner channel component can include a generally cylindrical shape, a generally elliptical cylindrical shape, etc. The main body and enlarged end portion of the shaft can be any suitable size and shape for engaging the proximal strut and being at least partially received in the inner channel component and the outer cage component. Suitable shapes for the main body can include a generally cylindrical shape, a generally elliptical cylindrical shape, etc. Suitable shapes for the enlarged end portion can include a generally cylindrical shape, a generally elliptical cylindrical shape, etc. In some embodiments, the junction 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) and preferably with a microcatheter having an inner diameter of 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).

[0034] Suitable materials for forming the shaft, proximal strut, and collar desirably have a high tensile strength so that sufficient integrity can be produced for manufacturing and use, such as polymeric materials like UHMWPE, aramid, LCP, PET, or PEN, or metals such as tungsten, MP35N, stainless steel, or nitinol. The proximal strut slot can be any suitable shape for engaging the enlarged end portion.

[0035] In some embodiments, any of the above junction assemblies can be integrally joined to an endovascular device between the clot engaging portion and the elongated shaft. Examples of endovascular devices can include a stent, a thrombectomy device, a coil retriever, equivalents now known or later discovered, or combinations thereof.

[0036] The description contained herein is exemplary of implementations of the present disclosure and is intended to be used in connection with claims to patent which are hereby incorporated by reference and which are set forth below. As described herein, the present disclosure contemplates many variations and modifications of the joint assembly, including, for example, different positioning of the shaft, proximal struts, and grommet, utilization of any of a number of materials for each element or member, incorporation of additional elements or members. These modifications will be apparent to an ordinary person having ordinary skill in the art to which the present disclosure pertains, and are intended to be within the scope of the following claims.

Claims

1. A proximal mechanical locking assembly for a thrombectomy device, comprising: a shaft comprising a main body and an enlarged end; an inner channel component comprising a full collar formed on a proximal end of the inner channel component; and an outer cage component comprising a partial collar formed on the outer cage component, wherein the partial collar of the outer cage component at least partially surrounds the shaft, and the full collar of the inner channel component completely surrounds the partial collar of the outer cage component.

2. The proximal mechanical locking assembly of claim 1, wherein the enlarged end of the shaft defines a shaft step with the main body of the shaft.

3. The proximal mechanical locking assembly of claim 1, wherein the full collar of the inner channel component is cylindrical.

4. The proximal mechanical locking assembly of claim 1, wherein the partial collar of the outer cage component is C-shaped.

5. The proximal mechanical locking assembly of claim 1, wherein the outer cage component has a diameter of 0.021 inches to 2 inches.

6. The proximal mechanical locking assembly of claim 1, wherein the inner channel component has a diameter of 0.001 inches to 0.021 inches.

7. A method of forming a proximal mechanical locking assembly for a thrombectomy device, comprising: providing a shaft comprising a main body, an inner channel component comprising a full collar formed on a proximal end of the inner channel component, and an outer cage component comprising a partial collar formed on the outer cage component; positioning the outer cage component at least partially around the shaft; and 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 of claim 7, wherein the shaft further comprises an enlarged end.

9. The method of claim 8, wherein the enlarged end of the shaft defines a shaft step with the main body of the shaft.

10. The method of claim 9, wherein the full collar of the inner channel component is cylindrical.

11. The method of claim 7, wherein the partial collar of the outer cage component is C-shaped.

12. The method of claim 7, wherein the outer cage component has a diameter of 0.021 inches to 2 inches.

13. The method of claim 7, wherein the inner channel component has a diameter of 0.001 inches to 0.021 inches.

14. A proximal mechanical locking assembly for a thrombectomy device, comprising: a shaft comprising a main body and an enlarged end; an inner channel component comprising a proximal collar; and an outer cage component comprising a proximal strut comprising a slot opening through the proximal strut, wherein the proximal collar of the inner channel component at least partially surrounds the shaft, and the slot opening of the proximal strut of the outer cage component completely surrounds the proximal collar of the inner channel component. wherein the enlarged end portion is positioned within the slot opening of the outer race component, and the proximal collar of the inner passage component at least partially surrounds the enlarged end portion and the slot opening.

15. The proximal mechanical locking assembly of claim 14, wherein the inner passage component is curved.

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