Patent Description:
Recent clinical studies have shown that mechanical thrombectomy is an increasingly effective method of acute obstruction removal from blood vessels. Acute obstructions can include clots, misplaced devices, migrated devices, large emboli and the like. An ischemic stroke can result if an obstruction lodges in the cerebral vasculature. A pulmonary embolism can result if the obstruction, such as a clot, originates in the venous system or in the right side of the heart and lodges in a pulmonary artery or branch thereof. Mechanical thrombectomy typically involves advancing a thrombectomy device or stentriever to the occlusive clot, engaging with the clot and retracting the clot into the safety of a proximally placed guide or sheath.

However, despite the benefits provided by mechanical thrombectomy devices, there are limitations. For example, there are a number of procedural challenges that can place undue tension or compression on the device components. In cases where access involves navigating the aortic arch (such as coronary or cerebral blockages) the configuration of the arch in some patients makes it difficult to position a stentriever. These difficult arch configurations are classified as either type <NUM> or type <NUM> aortic arches with type <NUM> arches presenting the most difficulty. The tortuosity challenge is even more severe in the arteries approaching the brain. For example, it is not unusual at the distal end of the internal carotid artery that the device will have to navigate a vessel segment with a <NUM>° bend, a <NUM>° bend and a <NUM>° bend in quick succession over a few centimeters of vessel. Delivering the device through the tortuous anatomy to the target location can apply compressive loading on the device components and joint between the distal section and the shaft. Moreover, dislodgement force of the obstruction in the vessel and retrieval through the tortuosity of the vasculature can place high tensile loading on the joint. Retrieval of the obstruction into the access catheter can also place high forces on the device components and proximal joint to the shaft.

These endovascular devices can be integrally formed with joint assemblies, often connecting a clot engaging portion to an elongated shaft. These assemblies can rely on adhesive bonds, weld bonds, or soldering. Adhesive can be applied to ensure the components maintain the correct position and orientation but increased joint strength and integrity can be desirable in some instances.

Moreover, as shown in <FIG>, current proximal mechanical bonds on dual stent mechanical thrombectomy devices generally include a stepped nitinol shaft <NUM>, an outer cage component <NUM> with full cylindrical proximal collar <NUM>, and an inner channel component <NUM> with partial C-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 the appropriate crossing profile (and maintain <NUM> (<NUM>") or <NUM> (<NUM>") microcatheter compatibility) the design of the outer cage collar component requires that the nitinol tubing raw material used to form this component has a maximum outer diameter that is smaller than the microcatheter inner diameter. Forming a similar proximal mechanical lock is problematic if a larger diameter nitinol tubing raw material is specified for the outer cage component.

There therefore exists a need for an endovascular device with a proximal joint compatible with varying sizes of raw material tubing that has sufficient integrity for effectively capturing an obstruction for safe retrieval from a patient. <CIT> describes clot retrieval devices for removing an occlusive clot from a blood vessel. The clot retrieval devices comprise an inner tubular member <NUM> comprising a generally cylindrical section of interconnected struts which is connected at its proximal end by a strut to a partial collar. The clot retrieval devices further comprise an outer member having a proximal collar. <CIT> describes clot retrieval devices for removing an occlusive clot from a blood vessel. <CIT> describes a clot retrieval system for removing an occlusive clot from a blood vessel.

The invention is defined in claims <NUM>, <NUM> and <NUM>.

The above and further aspects of this disclosure are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the disclosure. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.

Specific embodiments of the present disclosure are now described in detail with reference to the figures, wherein identical reference numbers indicate identical or functionality similar elements. The terms "distal" or "proximal" are used in the following description with respect to a position or direction relative to the treating physician. "Distal" or "distally" are a respect to a position or direction relative to the treating physician. "Distal" or "distally" are a position distant from or in a direction away from the physician. "Proximal" or "proximally" or "proximate" are a position near or in a direction toward the physician.

Accessing cerebral, coronary and pulmonary vessels involves the use of a number of commercially available products and conventional procedural steps. Access products such as stentrievers and thrombectomy devices are described elsewhere and are regularly used in endovascular procedures. See, for example <CIT>. It is assumed in the descriptions below that these products and methods are employed in conjunction with the device and methods of this disclosure and do not need to be described in detail.

The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Although the description of the disclosure is in many cases in the context of treatment of blood vessel occlusions, the disclosure may also be used in other body passageways as described herein.

An example of a joint assembly, as illustrated in <FIG>, can have a shaft <NUM>, an inner channel component <NUM> comprising a full collar <NUM> formed on proximal end of the inner channel component <NUM>, and an outer cage component <NUM> comprising a partial collar <NUM> formed on the outer cage component <NUM>. The shaft <NUM> can include a main body <NUM> and enlarged end <NUM>. In some embodiments, the full collar <NUM> of the inner channel component <NUM> can fully surround the partial collar <NUM> of the outer cage component <NUM>. The partial collar <NUM> of the outer cage component <NUM> can at least partially surround the shaft <NUM>. In some examples, the partial collar <NUM> of the outer cage component <NUM> can be C-shaped in cross section over at least a portion of its length such that the partial collar only partially surrounds the shaft in the portion of the partial collar <NUM> having the C-shaped cross section. In some examples, the outer cage component and the inner channel component can each respectively include an integrally joined proximal strut. The diameter of the collar <NUM> of the inner channel component <NUM> can range from about <NUM> (<NUM> inches) to about <NUM> (<NUM> inches) (e.g. <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches)). Similarly, the diameter of the collar <NUM> of the outer cage component <NUM> can range from about <NUM> (<NUM> inches) to about <NUM> (<NUM> inches) (e.g. <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches)). The diameter of the collar <NUM> of the outer cage component <NUM> can be measured based on the outer perimeter of a circle including the arc of the C-shaped collar <NUM>.

As shown in <FIG>, a previously disclosed joint assembly can include a shaft <NUM> including a main body <NUM> and an enlarged step <NUM>, a proximal strut <NUM> engaging with shaft <NUM>, and a locking collar <NUM> engagingly receiving at least a portion of main body <NUM> and at least a portion of proximal strut <NUM> to lock the assembly into place. It may further include a proximal strut slot <NUM>. Undue tension can elicit sufficient tensile stress on the shaft to cause the proximal strut to disengage from the enlarged step of the shaft, thereby causing the enlarged end to deform. This can result in disassembly of the joint device of the stentriever or thrombectomy device during dislodgement of the obstruction or as it is withdrawn proximally around a bend in a tortuous vessel, or the potential escape of the captured clot. <FIG> show an alternative joint assembly embodiment in accordance with this disclosure. This joint assembly can include a shaft <NUM> with a main body <NUM> and an enlarged end <NUM>. In this embodiment, inner channel collar <NUM> and the inner channel component such as proximal strut <NUM> are integrally joined to each other and the inner channel collar <NUM> is attached to the outer cage proximal strut <NUM> by any suitable means. The outer cage proximal strut <NUM> can be distal of the shaft <NUM> and at the proximal end of the stentriever. The inner channel collar <NUM> can have the same diameter as the raw material tubing from which it is cut. This removes the need for separate outer cage and inner channel components to achieve the mechanical lock between components in the assembly. In some embodiments, the outer cage proximal strut <NUM> can engage the inner channel collar <NUM> such that the inner channel collar <NUM>, shaft <NUM>, and outer cage proximal strut <NUM> are lockingly engaged by friction-fit. The friction-fit engagement can prevent the outer cage proximal strut <NUM> from disengaging from the enlarged end <NUM> of the shaft <NUM> when the joint assembly is integrally formed into an endovascular device and the endovascular device is under load.

The proximal strut <NUM> of the outer cage <NUM> can further include a strut slot <NUM> having an opening in which a portion of the enlarged end <NUM> of the shaft <NUM> can be positioned. When the enlarged end <NUM> of the shaft <NUM> is positioned in the slot <NUM> of the proximal strut <NUM> of the outer cage, the inner channel collar <NUM> can be positioned to at least partially surround the enlarged end <NUM> of the shaft <NUM> and the slot <NUM> of the proximal strut <NUM> of the outer cage to effectively secure the enlarged end <NUM> within the slot <NUM>.

As shown in <FIG>, a joint assembly can include a shaft <NUM>, a first proximal strut <NUM>, a locking collar <NUM>, and a second proximal strut <NUM>. The first and second proximal struts <NUM>, <NUM> are distal of the shaft <NUM> but at the proximal end of the stentriever. The shaft <NUM> can include a main body <NUM> and an enlarged end <NUM>. The enlarged end <NUM> can include a top end <NUM> and a bottom end <NUM>. The first proximal strut <NUM> can include a first strut slot <NUM>. The second proximal strut <NUM> can include a second strut slot <NUM>. The first slot <NUM> can engage the top end <NUM> of the enlarged end <NUM> of the shaft <NUM>. As shown in <FIG>, the second slot <NUM> can engage the bottom end <NUM> of the enlarged end <NUM> of the shaft <NUM>. The locking collar <NUM> can at least partially cover the enlarged end <NUM> of the shaft <NUM>, first slot <NUM> of the first proximal strut <NUM>, and second strut slot <NUM> of the second proximal strut <NUM>. At least a portion of the enlarged end <NUM> may be received in the first proximal strut slot <NUM>, the second strut slot <NUM> of the second proximal strut <NUM>, or both the first slot <NUM> and the second slot <NUM>. The enlarged end <NUM> of the shaft <NUM> may define a shaft step <NUM> with the main body <NUM> of the shaft <NUM>. The proximal strut may further include a tail <NUM>.

As shown in <FIG>, a joint assembly can include a shaft <NUM>, a proximal strut <NUM>, and a locking collar <NUM>. The proximal strut <NUM> is distal of the shaft <NUM> but at the proximal end of the stentriever. The shaft <NUM> can include a main body <NUM> and an enlarged end <NUM>. The proximal strut <NUM> can include slot <NUM> and/or strut slits <NUM>, as shown in <FIG>. The slot <NUM> can engage the enlarged end <NUM> of the shaft <NUM>. As shown in <FIG>, locking collar <NUM> can include a distal face <NUM> and collar pins <NUM> near the distal face of locking collar <NUM>. <FIG> shows that the collar pins <NUM> can lock into strut slits <NUM> of the proximal strut <NUM> when the shaft <NUM> is pulled inside the locking collar <NUM>, forming a mechanical lock. Proximal strut <NUM> can include a flexible material such that its flexes to permit strut slits <NUM> to engage collar pins <NUM>. In this proposed design the collar will be locked in place, this mechanical lock will add extra tensile strength for advancement and retrieval, the use of UV glue may no longer be mandatory. During assembly, the operator need only place the proximal strut <NUM> over the enlarged end <NUM> of the shaft <NUM> and pull both through the locking collar <NUM>, and the flexible nitinol strut will lock in place on the collar pins <NUM>. The locking collar <NUM> constrains the proximal strut slot <NUM> relative to enlarged end <NUM> such that proximal strut slot <NUM> maintains engagement with enlarged end <NUM> under tensile load up to a force of from about 2N to 15N (e.g. 3N, 4N, 5N, 6N, 7N, 8N, 9N, 10N, 11N, 12N, 13N, 14N).

In some embodiments, the joint assembly can be any suitable size and shape to be compatible with microcatheters used for neurovascular device delivery. The proximal strut slot can be any suitable shape for engaging enlarged end. For example, suitable shapes for the proximal strut slot can include generally square, generally rectangular, generally circular, and the like. Both the inner channel component and the outer cage component can be any suitable shape for covering or enclosing at least a portion of the proximal strut slot and the enlarged end of shaft. Suitable shapes for outer cage component can include generally partially cylindrical, generally partially elliptical cylindrical, and the like. Suitable shapes for inner channel component can include generally cylindrical, generally elliptical cylindrical, and the like. Main body and enlarged end of shaft can be any suitable size and shape for engaging proximal strut and being received, at least partially, in the inner channel component and the outer cage component. Suitable shapes for main body can include generally cylindrical, generally elliptical cylindrical, and the like. Suitable shapes for enlarged end can include generally cylindrical, generally elliptical cylindrical, and the like. In some embodiments, the joint assembly can be sized to be compatible with microcatheters with an inner diameter of <NUM> (<NUM> inches) or less (e.g. <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches)), and preferably with a microcatheter having an inner diameter of <NUM> (<NUM> inches) or less (e.g. <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches)).

Suitable materials for forming the shaft, proximal strut, and collar ideally have a high tensile strength such that sufficient integrity for manufacturability and use can be produced, such as for example polymers 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.

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

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