Clot retrieval device with flexible collapsible frame

Abstract

The invention is entitled "Clot retrieval device with flexible collapsible frame." The invention provides a clot retrieval device including an inner inflatable member and an outer inflatable member, each inflatable member formed by a respective strut frame such that the outer inflatable member has larger cell openings than the inner inflatable member. The outer inflatable member can have multiple discrete body segments spaced apart relative to a longitudinal axis of the device. Adjacent discrete body segments can be joined by a pair of tapered connecting arms that are capable of bending at a small radius of curvature compared to the body segments. Some or all of the body segments can include radiopaque markers positioned to show a circumference of the respective body segment and slightly staggered relative to the longitudinal axis of the device such that the markers nest when the device is collapsed for delivery.

Description

TECHNICAL FIELD

[0001] The present invention relates to devices and methods for removing acute occlusions from blood vessels. More specifically, the present invention relates to removing occlusions from cerebral arteries in patients with acute ischemic stroke (AIS), from pulmonary arteries in patients with pulmonary embolism (PE), from coronary arteries or graft vessels in patients with myocardial infarction (MI), and from other peripheral arterial and venous vessels in which clots or other occlusions (e.g., malpositioned devices, migrated devices, large emboli) cause occlusion. BACKGROUND

[0002] Thrombotic embolism occurs when a partial or complete thrombus detaches from the vessel wall. This clot, now called an embolus, is subsequently transported along the direction of blood flow. If the clot lodges in the cerebral vasculature, it can cause an ischemic stroke. If the clot originates from the venous system or the right side of the heart and lodges in the pulmonary artery or its branches, it can cause a pulmonary embolism. Clots can also be released not in the form of an embolus, but rather form locally and occlude the vessel, a mechanism that is more common in the formation of coronary artery occlusions.

[0003] There are many access challenges that make it difficult to deliver a therapeutic device to a clot or other occlusion. In cases involving navigation of the aortic arch, such as for coronary or cerebral occlusions, the arch configuration of some patients makes it difficult to position a guide catheter. These difficult arch configurations are classified as type 2 or type 3 aortic arches, with type 3 arches presenting the greatest difficulty. In the arteries approaching the brain, tortuosity challenges are even more severe. For example, at the distal end of the internal carotid artery, the device will have to navigate segments of vessels with 180° bends, 90° bends, and 360° bends in rapid succession over a few centimeters of vessel, a situation that is not uncommon. In the case of pulmonary embolism, access can be obtained through the venous system and then through the right atrium and ventricle of the heart. The right ventricular outflow tract and pulmonary artery are delicate vessels that can be easily damaged by inflexible or high-profile devices. For these reasons, it is desirable for an occlusion retrieval device to be compatible with a delivery catheter that has a low profile and high flexibility.

[0004] The vasculature in the regions where clots can lodge is often delicate and fragile. For example, neurovascular vessels are fragile and are located in a soft tissue bed compared to similarly sized vessels elsewhere in the body. Excessive tension applied to these vessels can cause perforation and hemorrhage. Pulmonary vessels are larger than those of the cerebral vasculature, but are also of a fragile nature, particularly the higher order vessels.

[0005] Clots can include any of a range of morphologies and consistencies. Long strands of softer clot material can tend to stay at bifurcations or trifurcations, causing multiple vessels to be simultaneously occluded over a significant length. More mature and organized clot material can be more difficult to compress than softer, fresher clot material, and under blood pressure, it can cause the compliant vessels containing the material to dilate.

[0006] Clots can vary not only in shape and consistency, but also greatly in length, even within any one given region of anatomy. For example, the length of a clot occluding a middle cerebral artery in an ischemic stroke patient can range from a few millimeters to a few centimeters.

[0007] Stent-like clot retrievers are increasingly used to remove clots and other blockages from cerebral vessels of acute stroke patients. These stent-like clot retrievers are self-expanding devices that resemble stents attached to the end of a long shaft, which are advanced through a microcatheter and deployed across a clot blockage in order to capture and retrieve the clot blockage. They rely on a pinching mechanism to grasp the clot by capturing it between the self-expanding stent-like body and the vessel wall.

[0008] Typically, stent-like clot retrievers rely on their outward radial force (RF) to maintain their grasp on the clot. If the RF is too low, the stent-like clot retriever will lose its grasp on the clot, but if the RF is too high, the stent-like clot retriever can damage the vessel wall and can require excessive force to withdraw. Because clots vary in morphology from patient to patient, the RF required to grasp the clot also varies. Because vessel fragility and geometry also vary from patient to patient, the RF required to reduce the risk of vessel trauma also varies.

[0009] In some treatments, some known stent-like clot retriever designs can lose their grasp on the clot when withdrawn proximally around a bend in a tortuous vessel. This is often because the struts of the stent-like clot retriever are placed under tension as it retracts. This tension is caused by friction between the device and the vessel, and it increases if additional load is applied, such as that provided by the clot. At a bend, the struts on the outside of the bend are placed under higher tension than the struts on the inside. To achieve the lowest possible energy state, the outer surface of the stent moves toward the inner surface of the bend, which reduces the tension in the struts, but also reduces the expanded diameter of the stent-like clot retriever.

[0010] Some treatments rely on pinning the clot between a stent-like clot retriever and the vessel wall, and thus can not effectively constrain the clot when passing through a branch vessel or when entering a vessel larger than the fully inflated diameter of the stent-like clot retriever. Pinning the clot between a stent-like clot retriever and the vessel wall in order to remove the clot from the vessel also results in high shear forces against the sides of the clot as it is removed, potentially releasing fragments of the clot. If these fragments are not held by the device, they can be released, causing further obstruction in the distal vasculature.

[0011] In some treatments, the stent-like clot retriever can be shorter than the clot itself. A device shorter than the clot is less likely to restore flow through the occluded region upon deployment, and thus the pressure gradient across the clot remains a significant obstacle to its removal. Simply manufacturing such a device to be longer can make it difficult to track through tortuous anatomy and can cause trauma to the vasculature, taking more force to withdraw and potentially getting stuck and requiring surgical removal.

[0012] For many reasons, including some or all of the above limitations, physicians often need to use a clot retrieval device for multiple passes in order to completely remove an obstructive clot. However, each time the clot retrieval device is withdrawn, access to the target site is lost. The initial access step of placing a large bore catheter is not needed to be repeated, as it remains in place after the initial clot retrieval attempt. Only the step of accessing the clot site after placing the large bore catheter needs to be repeated. Thus, it is necessary to re-advance the guidewire and microcatheter to access and re-pass the clot, and then remove the guidewire and advance the clot retrieval device through the microcatheter. Navigating the guidewire and microcatheter to the clot can take a considerable amount of time, especially if the vessel is tortuous. This additional time and device manipulation both add to the risk to which the patient is exposed. SUMMARY

[0013] Examples disclosed herein generally include a clot retrieval device having an inner inflatable member and an outer inflatable member, each inflatable member formed by a respective strut frame, such that the outer inflatable member has larger cell openings than the inner inflatable member. The outer inflatable member can have a plurality of discontinuous body segments spaced apart relative to a longitudinal axis of the device. Adjacent discontinuous body segments can be joined by a pair of tapered connecting arms that are capable of bending at a small radius of curvature compared to the body segments. This small radius of curvature can have a range of values that depend on tortuosity of the vasculature in which the device is inflated. When the device is in a straight blood vessel, this radius of curvature will be approximately equal to 0 mm, and when the device is in a blood vessel with a 180 degree bend, this radius of curvature will be approximately equal to 0.5 mm. Some or all of the body segments can include radiopaque markers positioned to show a circumference of the respective body segment and slightly staggered relative to the longitudinal axis of the device, such that the markers nest when the device is collapsed for delivery.

[0014] An example clot retrieval device has a collapsed configuration and an inflated configuration. The clot retrieval device is configured to remove a clot from a blood vessel. The clot retrieval device has an inner inflatable member and an outer inflatable member. The inner inflatable member has a first strut frame and the outer inflatable member has a second strut frame. The second frame at least partially radially surrounds the inner inflatable member.

[0015] The closed cells of the second frame of the outer inflatable member can be larger than the closed cells of the first frame of the inner inflatable member.

[0016] The outer inflatable member can have a first body segment and a second body segment connected by two connecting arms, with the first body segment positioned in a proximal direction relative to the second body segment. Each of the two connecting arms can respectively have a tapered shape that is wider at the arm proximate to the first proximal body segment and narrower at the arm proximate to the second distal body segment. As FIG. IB and FIG. 4C As shown, approximate values for the marker dimensions are as follows: the height "H" has a value of 0.075 mm, the strut width "W1" has a value of 0.16 mm, the strut width "W2" has a value of 0.08 mm, and the strut width "W3" has a value of 0.20 mm. Thus, the approximate percentage change in width between "W1" and "W2" is a decrease of 50%, and the approximate percentage change in width between "W2" and "W3" is an increase of 60%. The outer inflatable member can have additional body segments connected to the first body segment and / or the second body segment by additional connecting arms.

[0017] The outer expandable member can have at least two inlet mouths in the second frame, including a pair of inlet mouths between the first body segment and the second body segment. Each of the two inlet mouths between the first body segment and the second body segment can have a respective opening bounded by the first body segment, the second body segment, and the two connecting arms.

[0018] The first body segment can have at least two pairs of struts, each pair of struts terminating at a respective distal apex and forming a proximal boundary of a respective inlet mouth of the two inlet mouths.

[0019] The two connecting arms between the first body segment and the second body segment of the outer expandable member can extend substantially parallel to a longitudinal axis of the device.

[0020] The two connecting arms between the first body segment and the second body segment of the outer expandable member can be positioned about a circumference of the outer expandable member approximately 180° from one another.

[0021] The first body segment and the second body segment can be connected to one another only via the two connecting arms.

[0022] Each of the two connecting arms can be configured to bend with a curvature having a radius that is smaller than a radius of curvature of a majority of the struts of the first body segment and the second body segment when the clot retrieval device is pulled proximally through a tubular vasculature comprising an approximately 180° bend.

[0023] The outer expandable member can have three or more body segments, each body segment substantially similar in shape to the first body segment and the second body segment. The outer expandable member can include pairs of tapered connecting arms such that each respective pair of tapered connecting arms joins longitudinally adjacent body segments of the three or more body segments. The tapered connecting arms can be similar in shape and orientation to the connecting arms between the first body segment and the second body segment.

[0024] One or both of the first body segment and the second body segment can include four or more radiopaque markers positioned about a circumference of the respective body segment. Each of the four or more radiopaque markers can be offset from an adjacent radiopaque marker of the four or more radiopaque markers when the clot retrieval device is in the collapsed configuration. The markers can be offset from the adjacent radiopaque markers relative to a longitudinal axis of the device. Alternating ones of the four or more radiopaque markers can be aligned in a plane normal to the longitudinal axis when the clot retrieval device is in the collapsed configuration.

[0025] The first body segment can include a first set of four or more radiopaque markers. The second body segment can include a second set of four or more radiopaque markers. The first set of four or more radiopaque markers and the second set of four or more radiopaque markers can be spaced apart by approximately 8 millimeters in a direction of the longitudinal axis when the clot retrieval device is in the expanded configuration. The first set of four or more radiopaque markers and the second set of four or more radiopaque markers can be spaced apart by approximately 10 millimeters in a direction of the longitudinal axis when the clot retrieval device is in the collapsed configuration.

[0026] Each of the four or more radiopaque markers can include a radiopaque material positioned in an eyelet.

[0027] At least two of the four or more radiopaque markers can align with a respective one of the two connecting arms in a direction of the longitudinal axis.

[0028] Another example clot retrieval device can have a collapsed configuration and an expanded configuration. The clot retrieval device is configured to remove a clot from a blood vessel. The structure and function of this example clot retrieval device can be combined with the structure and features of the previous example clot retrieval devices.

[0029] An example clot retrieval device includes an inner expandable member having a first strut frame and an outer expandable member having a second strut frame. The second strut frame can form larger closed cells than the closed cells of the first frame of the inner expandable member. The second frame can at least partially radially surround the first frame of the inner expandable member.

[0030] An example clot retrieval device can include four or more radiopaque markers attached to the second strut frame and positioned to indicate a circumference of the outer expandable member. The radiopaque markers can be further positioned such that each of the radiopaque markers is offset relative to a longitudinal axis of the device from a respective circumferentially adjacent radiopaque marker when the clot retrieval device is in the collapsed configuration.

[0031] The outer expandable member can include discontinuous body segments spaced apart from each other in a direction of the longitudinal axis. The radiopaque markers can be positioned to indicate a circumference of a body segment of the discontinuous body segments.

[0032] An example clot retrieval device can include a first body segment and a second body segment, where the first body segment is positioned in a proximal direction relative to the second body segment. The outer expandable member can include two connecting arms joining the first body segment to the second body segment. Each of the two connecting arms can respectively have a tapered shape that is wider near the proximal first body segment and narrower near the distal second body segment. At least two of the four or more radiopaque markers can be aligned with a respective one of the two connecting arms in the direction of the longitudinal axis.

[0034] The outer expandable member can include two inlet mouths in the second frame. Each of the two inlet mouths can include a respective opening defined by the first body segment, the second body segment, and the two connecting arms.

[0035] The first body segment can include four or more radiopaque markers forming a first set of markers, and the second body segment can include a second set of four or more radiopaque markers positioned to indicate a circumference of the second body segment. The second set of radiopaque markers can be positioned such that each of the second set of radiopaque markers is offset relative to the longitudinal axis of the device from a respective adjacent radiopaque marker of the second set when the clot retrieval device is in the collapsed configuration. The markers of the first set of radiopaque markers can be similarly offset.

[0036] The two connecting arms can be positioned about 180° apart from each other around the circumference of the outer expandable member. BRIEF DESCRIPTION OF DRAWINGS

[0037] FIG. 1A An isometric view of an exemplary clot retrieval device according to aspects of the present disclosure is shown.

[0038] FIG. IB A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure. FIG. 1A

[0039] FIG. 2A A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure. FIG. 1A

[0040] A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure. FIG. 2B FIG. 2A A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure.

[0041] FIG. 2C FIG. 2A A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure.

[0042] FIG. 3A A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure. FIG. 1A FIG. 2A A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure.

[0043] FIG. 3B FIG. 3A A close-up view of a portion of the clot retrieval device shown, including a tapered strut according to aspects of the present disclosure.​​​​FIG. 3A A view of the clot retrieval device shown with the inner inflatable member of the clot retrieval device removed from view.

[0044] FIG. 3C A close-up view of a portion of the clot retrieval device shown including a tapered strut according to aspects of the present application. FIG. 3A A view of the clot retrieval device shown with the outer inflatable member of the clot retrieval device removed from view.

[0045] FIG. 4A A linear view of the outer inflatable member of the clot retrieval device cut and flattened along the centerline shown. FIG. 2B and FIG. 3B A linear view of the outer inflatable member of the clot retrieval device cut and flattened along the centerline shown.

[0046] FIG. 4B A close-up view of a portion of the clot retrieval device shown including a tapered strut according to aspects of the present application. FIG. 4A

[0047] A close-up view of a portion of the clot retrieval device shown including a tapered strut according to aspects of the present application. FIG. 4C FIG. 4B A close-up view of a portion of the clot retrieval device shown including a tapered strut according to aspects of the present application.

[0048] FIG. 5A A plan view of the distal end of the clot retrieval device shown. FIG. 1A

[0049] A view of the clot retrieval device shown with the inner inflatable member of the clot retrieval device removed from view. FIG. 5B FIG. 5A A view of the clot retrieval device shown with the outer inflatable member of the clot retrieval device removed from view.

[0050] FIG. 5C FIG. 5A A view of the clot retrieval device shown with the outer inflatable member of the clot retrieval device removed from view.

[0051] FIG. 6A An isometric view of another example clot retrieval device according to aspects of the present application is shown.

[0052] FIG. 6B A close-up view of a portion of the clot retrieval device shown including a tapered strut according to aspects of the present application. FIG. 6A

[0053] A close-up view of a portion of the clot retrieval device shown including a tapered strut according to aspects of the present application. FIG. 7A FIG. 6A A plan view of the first side of the clot retrieval device shown.

[0054] FIG. 7B FIG. 7A A view of the clot retrieval device shown with the inner inflatable member of the clot retrieval device removed from view. ​​​​​

[0055] FIG. 7C A view of the clot retrieval device is shown with the outer inflatable member of the clot retrieval device removed from the illustration. FIG. 7A

[0056] FIG. 8A A plan view of the second side of the clot retrieval device is shown, which is viewed at 90° from the first side view shown. FIG. 6A FIG. 7A

[0057] FIG. 8B A view of the clot retrieval device is shown with the outer inflatable member of the clot retrieval device removed from the illustration. FIG. 8A

[0058] FIG. 8C A view of the clot retrieval device is shown with the outer inflatable member of the clot retrieval device removed from the illustration. FIG. 8A

[0059] FIG. 9 A linear view of the outer inflatable member of the clot retrieval device is shown cut and flattened along the centerline shown. FIG. 7B FIG. 8B

[0060] FIG. 9 A plan view of the distal end of the clot retrieval device is shown. FIG. 4B

[0061] A view of the clot retrieval device is shown with the outer inflatable member of the clot retrieval device removed from the illustration. FIG. 4C FIG. 4B

[0062] A view of the clot retrieval device is shown with the outer inflatable member of the clot retrieval device removed from the illustration. FIG. 4B FIG. 4C A view of a portion of the outer inflatable member is shown as indicated.

[0063] FIG. 4B A view of a portion of the outer inflatable member is shown as indicated.

[0064] A view of a portion of the outer inflatable member is shown as indicated. FIG. 4C FIG. 10A A view of a portion of the outer inflatable member is shown as indicated.

[0065] A view of a portion of the outer inflatable member is shown as indicated. FIG. 10B A view of a portion of the outer inflatable member is shown as indicated.

[0066] FIG. 10A A view of a portion of the outer inflatable member is shown as indicated.​​​​​​​​FIG. 10C side view of a portion of the expandable member shown.

[0067] FIG. 10A and FIG. 11A are radiographic images of exemplary clot retrieval devices according to aspects of the present application.

[0068] FIG. 11B illustrations of alternative distal portions of exemplary clot retrieval devices according to aspects of the present application. DETAILED DESCRIPTION

[0069] The specific embodiments of the present application now will be described in detail below. Identical reference numerals are used throughout the drawings and terminology indicating directions such as distal, proximal, front, back, etc., relate to the embodiment as it is shown. 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.

[0070] 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 guide wires, guide catheters, angiographic catheters, and microcatheters are described elsewhere and are commonly used in catheterization laboratory procedures. These products and methods are assumed to be used in conjunction with the devices and methods of the present application in the following description and do not need to be described in detail.

[0071] The following detailed description is merely exemplary in nature and is not intended to limit the application or the application and uses of the application. Although the description of the application is in many instances in the context of treating intracranial arteries, the application can also be used in other body passageways as previously described.

[0072] FIG. 11AThe distal portion of an exemplary clot retrieval device 100 in an expanded configuration is shown. The clot retrieval device 100 generally extends to define a longitudinal axis AA and has at its distal end a distal coil 108, an outer expandable member 102 and an inner expandable member 103 extending proximally from the distal coil 108 and coaxially, and a proximal coil 104 extending proximally from the outer expandable member 102 and the inner expandable member 103. The device 100 may include additional features such as an elongated shaft 106, a sleeve 105, and an indicator strip 107. The device 100 may include a distal engagement or retainer 109 for engaging the distal coil 108 to the outer expandable member 102 and the inner expandable member 103. The device 100 may include a proximal engagement or retainer 112 for engaging the proximal coil 104 to the outer expandable member 102 and the inner expandable member 103. The joints 109, 112 can be configured to be used with a clot retrieval device having two expandable layers 102, 103, such as the clot retrieval device described in U.S. Patent 10,390,850, the entire contents of which are incorporated herein by reference.

[0073] FIG. 12A It shows FIG. 12B A close-up of a portion of the clot retrieval device shown, which includes a tapered support bar according to an aspect of the invention.

[0074] FIG. 12A A plan view of the first side of the clot retrieval device 100 is shown. FIG. 13A As shown FIG. 13B The diagram shows a view of the clot retrieval device 100, with the internal expandable member 103 removed for illustrative purposes. FIG. 14 As shown FIG. 1A The diagram shows a view of the clot retrieval device 100, in which the external expandable member 102 has been removed for illustrative purposes. FIG. IB A plan view of the second side of the clot retrieval device 100 is shown, the second side being from... FIG. 1A The first side view shown is viewed at 90°. FIG. 2A As shown FIG. 2B The diagram shows a view of the clot retrieval device 100, with the internal expandable member 103 removed for illustrative purposes. FIG. 2A As shown FIG. 2C The diagram shows a view of the clot retrieval device 100, in which the external expandable member 102 has been removed for illustrative purposes. FIG. 2A It shows along FIG. 3A and FIG. 2A The line BB shown is a linear view of the external expandable member 102 cut and flattened. FIG. 3B As shown FIG. 3A A close-up of a portion of the externally expandable member 102 shown.FIG. 3C A close-up view of a portion of the outer inflatable member 102 is shown. FIG. 3A A close-up view of a portion of the outer inflatable member 102 is shown. FIG. 4A A plan view of the distal end of the clot retrieval device 100 is shown. FIG. 2B A close-up view of a portion of the outer inflatable member 102 is shown. FIG. 3B A view of the clot retrieval device 100 is shown with the inner inflatable member 103 removed for illustrative purposes. FIG. 4B A view of the clot retrieval device 100 is shown with the outer inflatable member 102 removed for illustrative purposes. FIG. 4A A view of the clot retrieval device 100 is shown with the outer inflatable member 102 removed for illustrative purposes.

[0075] As described in greater detail with respect to FIG. 4C and FIG. 4B The outer inflatable member 102 can include tapered struts 129, 130 that join the body segments 126, 127, 128. The shape of the tapered struts 129, 130 is configured to provide flexibility to the outer inflatable member 102 to facilitate withdrawal of the device 100 from tortuous blood vessels when the occlusion is at least partially defined by the outer inflatable member 102. Additionally or alternatively, the shape of the tapered struts 129, 130 is configured to promote circumferential apposition of the outer inflatable member 102 to the vessel wall as the device 100 is withdrawn through tortuous vasculature when the occlusion is at least partially defined by the outer inflatable member 102.

[0076] As described in greater detail with respect to FIG. 5A and FIG. 5B The outer inflatable member 103 can include interleaved radiopaque markers positioned to facilitate visualization of the device 100 during treatment while also maintaining a low profile collapsed configuration of the outer inflatable member 102 to facilitate collapsing the device 100 across a clot or other occlusion.

[0077] With reference to FIG. 5A collectively, the outer inflatable member 102 and the inner inflatable member 103 can be collapsed into a restraining sheath (e.g., a microcatheter) sized to traverse a clot or other occlusion. The outer inflatable member 102 and the inner inflatable member 103 are each configured to self-expand upon release from the restraining sheath. In the expanded configuration, the device 100 can facilitate clot retrieval, flow restoration, and / or dissection protection.

[0078] Both the inner expandable member 102 and the outer expandable member 103 are preferably made of a material that is capable of automatically recovering its shape once released from the collapsed delivery configuration. Super-elastic or pseudo-elastic materials such as Nitinol or similar alloys are particularly suitable. The material can have a high recoverable strain sufficient to elastically collapse and expand as described herein. The material can be in a variety of forms such as wire or strip or sheet or tube. A particularly suitable manufacturing process is laser cutting of a Nitinol tube followed by heat setting and electropolishing of the resulting structure to form the framework of struts and connecting elements. The framework can be any of a large range of shapes as understood by those of skill in the relevant art in light of the teachings disclosed herein. The framework can be made visible under fluoroscopy by the addition of alloying elements or by a variety of other coatings or marker bands. For example, the framework can include materials and / or markers with radio-opaque materials including but not limited to barium sulfate, bismuth subcarbonate, barium chloro- oxide, gold, tungsten, platinum, iridium, tantalum, and alloys thereof. In particular, in some examples, the framework can include radio-opaque markers with iridium alloys, and more particularly platinum-iridium alloys.

[0079] The inner expandable member 103 is preferably configured to expand to a diameter D2 that is less than the diameter of the smallest blood vessel in which it is intended to be used. This diameter D2 is typically less than 50% of the diameter Dl of the outer expandable member 102, and can be as low as 20% or less of the outer member diameter Dl.

[0080] The distal support frame region can incorporate strut elements from the framework of the outer expandable member 102 and / or the inner expandable member 103, such as the expanded portion 110 of the inner expandable member 103 and the distal portion 128 of the outer expandable member 102. The strut geometry of the distal support frame region can be shaped as shown herein or as described with respect to a compatible stent-like clot retriever, including but not limited to as disclosed in U.S. Patent 10,390,850. The distal support frame region can also include fine wires or fibers to provide additional support frame with minimal impact on the overall device profile or delivery capabilities. Suitable materials desirably have a high tensile strength so that ultra-fine wires or fibers with sufficient integrity for manufacturability and use can be produced, such as polymeric materials like UHMWPE, aramid, LCP, PET, or PEN or metals like tungsten, MP35N, stainless steel, or Nitinol.

[0081] In each of the expanded and collapsed configurations, the inner and outer expandable members 102, 103 define respective tubular bodies. Preferably, the tubular bodies are coaxial about a longitudinal axis A-A. When the inner and outer expandable members 102, 103 are in the expanded configuration, the device 100 includes a receiving space 111 within the outer expandable member 102 and outside the inner expandable member 103. The device 100 and the receiving space 111 are sized, shaped, and otherwise configured to allow the clot to be at least partially confined within the receiving space during a clot removal treatment. The interior of the inner expandable member 103, when expanded, is configured to provide a flow path through which blood can flow when the device 100 is expanded through the clot.

[0082] During a clot removal treatment, the length of the outer expandable member 102 can be about as long or longer than the length of the occlusive clot to remove many of the degrees of freedom of freedom of movement available to the clot. The outer member 102 includes an inlet opening 222 that is sized, shaped, and otherwise configured to provide a primary degree of freedom of movement available to the clot, and thus expansion of the outer member 102 pushes the clot into the receiving space 111. The outer member 102 has a plurality of inlet mouths 122 to receive the clot. In this way, the inlet mouths 122 allow portions of the clot to enter the receiving space 111 of the outer member 102, and thus allow the clot to be retrieved without being overly compressed. This is advantageous because the inventors have found that compression of the clot dehydrates it, which in turn increases the frictional properties of the clot and increases its stiffness, all of which make the clot more difficult to dislodge and remove from the blood vessel. This compression can be avoided if the clot migrates inward through the struts of the outer member 102 as the support frame migrates outward toward the vessel wall.

[0083] The inlet mouths 122 can further allow the outer member 102 to apply force to the clot in a direction that is substantially parallel to the direction in which the clot is pulled from the blood vessel, i.e., substantially parallel to the central axis of the blood vessel, when retracted. This means that outward radial forces applied to the vasculature can be kept to a minimum, which in turn means that the action of the clot retrieval device 100 on the clot does not serve to increase the force required to move the clot out of the blood vessel, thereby protecting delicate cerebral blood vessels from harmful radial and tensile forces.

[0084] The outer expandable member 102 includes a proximal strut 120 that is connected to the proximal collar 112 at its proximal end and to the proximal body segment 126 at its distal end. The proximal strut 120 can have a tapered profile or otherwise be configured to provide a gradual stiffness transition from the shaft 106 to the tubular body of the outer expandable member 102.

[0085] The proximal body section 126 is connected to the intermediate body section 127 by two connecting arms 129 extending from a proximal junction 139 to a distal junction 140. The intermediate body section 127 is in turn connected to the distal body section 128 by two connecting arms 130 extending from a proximal junction 141 to a distal junction 142. The region between the intermediate body section 127 and the distal body section 128 includes two inlet mouths 122 through which a clot can pass and into the receiving space 111 defined by the region between the inner member 102 and the outer member 103.

[0086] As FIG. 5C and FIG. 5A shown in greater detail, each of the connecting arms 129 can have a tapered profile tapering in width from a wider dimension Wl at the respective proximal junction 139, 141 to a narrower width W2 near the respective distal junction 140, 142. At the distal junctions 140, 142, the connecting arms 129, 130 can expand to a width W3 that is wider than the narrower width W2 to accommodate the branching distal struts 170. The connecting arms 129, 130 can have a substantially uniform height H (thickness). The height H can be consistent with the strut thickness of the majority of the outer expandable member 102.

[0087] In one example, as FIG. IB and FIG. 4C shown, approximate values for the dimensions are as follows: the height H has a value of about 0.075 mm, the proximal strut width Wl has a value of about 0.16 mm, the distal strut width W2 has a value of about 0.08 mm, and the bifurcated strut width W3 has a value of about 0.20 mm. Thus, the approximate percentage change in width between the proximal width Wl and the distal width W2 is a decrease of 50%, and the approximate percentage change in width between the distal width W2 and the bifurcated width W3 is an increase of 60%.

[0088] The tapered shape of the connecting arms 129, 130 can be configured to flex to reduce the withdrawal force around a vessel curvature compared to a similar configuration of a stent-like clot retriever device having non-tapered connecting arms. The arms 129, 130 can be configured to flex with a curvature having a greater curvature (smaller radius of curvature) compared to the majority of the struts within the outer expandable member 102 (see radius r as shown in FIG. 4A .

[0089] The connecting arm 129 between the proximal body segment 126 and the intermediate body segment 127 of the outer inflatable member 102 can be substantially aligned with the connecting arm 130 between the intermediate body segment 127 and the distal body segment 128 to align the neutral axis of the body segments 126, 127, 128 during bending. In another embodiment, the connecting arm 129 between the proximal body segment 126 and the intermediate body segment 127 can be aligned at an angle, such as 90°, to the connecting arm 130 between the intermediate body segment 127 and the distal body segment 128.

[0090] As shown in more detail in FIGS. 1 1 A and 1 1 B, the proximal body segment 126 includes interconnected struts, with certain struts, such as strut 143, terminating at a distal apex 133 without a distal connecting element, and other struts, such as 144, terminating at junctions 145, 146. The intermediate body segment 127 includes interconnected struts, with certain struts, such as strut 147, terminating at a distal apex 134 without a distal connecting element, and other struts, such as strut 148, terminating at junctions 171. FIG. 4B FIGS. 1A-5C As shown in more detail in FIGS. 1 1 A and 1 1 B, the proximal body segment 126 includes interconnected struts, with certain struts, such as strut 143, terminating at a distal apex 133 without a distal connecting element, and other struts, such as 144, terminating at junctions 145, 146. The intermediate body segment 127 includes interconnected struts, with certain struts, such as strut 147, terminating at a distal apex 134 without a distal connecting element, and other struts, such as strut 148, terminating at junctions 171.

[0091] One or more of the body segments 126, 127, 128 can include a marker band or radiopaque feature, such as a gold or platinum marker or coil. In the illustrated embodiment, oval markers 121, 125 are shown secured in eyelets on the struts on the proximal body segment 126, the intermediate body segment 127, and the distal body segment 128. The markers 125 on the distal body segment 128 can be positioned to indicate to a user the position of the distal body segment 128, and thus the distal portion of the device 100, to aid in deployment accuracy of the device 100. The distal body segment 128 can include a single marker 125 indicating the position of the distal body segment 128, or a plurality of markers indicating the circumference of the distal body segment 128. Each of the proximal body segment 126 and the intermediate body segment 127 can include a plurality of oval markers 121 positioned circumferentially around the respective body segment 126, 127 to indicate to a user the inflated circumference CI and / or position of the respective body segment 126, 127 during treatment (where the circumference CI is the diameter D1 multiplied by π). In the illustrated embodiment, each of the proximal body segment 126 and the intermediate body segment 127 includes four markers 121 positioned approximately equidistant around the circumference CI of the outer inflatable member 102.

[0092] FIG. IB FIG. 4C is shown when the device 100 is constrained by a microcatheter or sheath, along with the outer inflatable member 102 inflated to the inflated circumference CI. The outer inflatable member 102 is shown in a straightened configuration, with the proximal body segment 126, the intermediate body segment 127, and the distal body segment 128 aligned along a common axis. FIG. IB FIG. 4C ​​​The line B-B shown is cut, laid flat, and collapsed to the outer inflatable member 102 corresponding to a height C2 of the circumference of the outer inflatable member 102. As FIG. 11B As shown in greater detail, the markers 121 on each of the proximal body segment 126 and the intermediate body segment 127 are staggered, offset (i.e., positioned at different distances from the proximal collar 112) in the direction of the longitudinal axis A-A to facilitate the collapse of the height C (circumference) of the outer inflatable member 102. Each of the respective markers 121 is connected to an elongate segment 172 shaped to nest the adjacent marker 121 between a junction (e.g., junction 141) and the respective connected marker 121. The elongate segments 172 and markers 121 are positioned circumferentially in an alternating fashion.

[0093] The struts in the body segments 126, 127, 128 can be configured such that during loading, the crowns or junctions (e.g., junctions 145 and 150 and other similarly shaped junctions) are not aligned at the same distance from the proximal collar. During loading or recapping, typically a higher force than the struts is needed to load the junctions (crowns) into the sheath, so if multiple crowns are loaded at the same time, the user can notice an increase in the loading force. By offsetting the crowns with alternative struts 144 and 151 having different lengths, the loading force can be reduced and the user’s perception improved.

[0094] The distal end of the distal body segment 128 includes a strut forming a tapered shape terminating at the distal junction 109, defining a closed end distal to the outer member 102. In FIG. 2B The distal body segment 128 is viewed in plan from the distal end of the device 100, with the inner inflatable member 103 removed in FIG. 3B The outer inflatable member 102 is removed in FIG. 4A The distal end of the distal body segment 128 can include a distal frame as shown herein, or an alternative distal frame that can be used with a stent-like clot retriever. The tapered portion of the distal body segment 128 is shaped and otherwise configured to prevent the outflow of clots or clot fragments that have entered the receiving space 111 between the inner member 102 and the outer member 103. The inflated distal strut 110 of the inner member 103 acts as an additional three-dimensional filter in conjunction with the closed end of the outer member 102 to further prevent the outflow of clots or clot fragments. In certain embodiments, this distal segment can include fiber attachment points (such as eyelets or other fiber attachment features), and fibers can be connected to the distal segment at these attachment points to form a distal mesh.

[0095] As FIG. 4B , FIG. 2B andFIG. 3B As shown in more detail, the inner expandable member 103 is configured to self-expand to a diameter D2 upon release from a restraining sheath, such as a microcatheter, that is larger than the expanded diameter Dl of the outer expandable member 102 and smaller than the diameter of the blood vessel in which the device 100 is configured to treat. The inner tubular member 103 comprises a more dense, smaller open cell support frame compared to the outer expandable member 102. The inner tubular member 103 is configured to provide a flow lumen through the device 100 to facilitate immediate restoration of blood flow past the clot upon deployment. Additionally or alternatively, the inner tubular member 103 is configured to frame the flow lumen through the clot to prevent release of debris that can otherwise lodge in the distal vasculature. The inner tubular member 103 comprises connected struts 131 that can contact the clot when initially deployed in the target blood vessel within the clot. Contact of the struts 131 of the inner tubular member 103 with the clot can provide additional grip and assist with initial displacement of the clot from the blood vessel upon retraction of the device.

[0096] The inner expandable member 103 comprises a generally cylindrical segment of interconnected struts 131 that is connected at its proximal end to the proximal junction 112 by struts 138 (or multiple struts). The distal end of the inner expandable member 103 comprises an expandable segment formed by expansion struts 110 that is of a larger diameter D2 than the main body segment of the inner tubular member 103. These expansion struts 110 are connected to a coil segment 118, which in this embodiment is laser cut from a tube from which the inner expandable member 103 is also cut during processing.

[0097] The shaft 106 can comprise a tapered spool and can be made of stainless steel, MP35N, Nitinol, or other materials with suitably high modulus and tensile strength. The shaft 106 can have indicator bands 107 on the shaft to indicate to the user when the distal end of the device is approaching the end of the microcatheter during insertion. These bands are positioned so that when they approach the microcatheter hub or hemostasis valve, they indicate that the distal tip of the device is approaching the end of the microcatheter. These indicator bands can be formed by printing or removing or masking areas of the shaft coating so that these areas are visually distinguished from the rest of the shaft. The indicator bands 107 can additionally be recessed below the surface of the shaft 106 to provide tactile feedback to the user as they approach the microcatheter.

[0098] A proximal coil 104 can extend from a distal portion of the shaft 106. The proximal coil 104 can be metallic and can be formed of stainless steel or a more radiopaque material such as platinum or gold or alloys of such materials. Additionally or alternatively, the coil can be coated with a low friction material or have a polymer jacket on the outer surface of the coil. Adjacent to the coil 104, a sleeve 105 can be positioned on the shaft 106. The sleeve 105 can comprise a polymer material and can be positioned over a tapered section of the shaft. The sleeve 105 can be made radiopaque by the addition of a filler material such as tungsten or barium sulfate. The sleeve 105 and shaft 106 can be coated with a material to reduce friction and thrombogenicity. The coating can consist of a polymer, a low friction lubricant such as silicone, a hydrophilic coating or a hydrophobic coating. The coating can also be applied to the outer member 102 and inner tubular member 103.

[0099] During assembly, the outer member 102 and inner tubular member 103 can be joined at the proximal junction 112 and distal junction 109. To minimize tension within the members 102, 103 during use, the length of the outer member 102 can be substantially the same as the length of the inner member 103 in the free expanded configuration and the collapsed, loaded configuration. The expansion struts 110 of the inner tubular member 103 elongate during loading so that the lengths of the inner and outer members are equal when fully loaded in a microcatheter. A length difference between the inner member 103 and the outer member 102 can still occur when the device is deployed in a small blood vessel or during the loading or deployment process. The coil 118 at the distal end of the inner tubular member 103 can accommodate the smaller length difference by stretching without the need to apply significant tensile or compressive forces to the device. In another embodiment, the coil 118 can be formed separately from the inner tubular member 103 and then assembled to the inner tubular member. The coil 118 can be formed of a stainless steel material, a polymer or a more radiopaque metal such as gold or platinum or alloys of such materials. The coil 118 can also be replaced with an elastic material of longitudinal length such as a low modulus polymer or elastomer.

[0100] In other embodiments, the inner member 103 can not be connected to the distal end of the outer member 102 at all or can be constrained within the outer member 102 without being fixedly attached. In other embodiments, the inner member 103 can have a non-cylindrical cross section, the diameter can be non-uniform, and can have a custom strut pattern to provide regions of different radial force or flexibility.

[0101] FIG. 4B An isometric view of another example clot retrieval device 200 is shown. As with the device 100 shown, FIG. 5A In contrast to the device 100 shown, FIG. 5BThe outer inflatable member 202 of the clot retrieval device 200 shown includes a plurality of intermediate body segments 227 instead of a single intermediate body segment 127. At least the proximal body segment 226 and the intermediate body segments 227 each include interconnected struts, with certain struts terminating in distal apices 233 without distal connection elements, and other struts terminating in junctions. FIG. 5C The device 200 shown includes three intermediate body segments 227. In accordance with the present disclosure, clot retrieval devices including the features described and shown herein can include one, two, three, four, five, or more intermediate body segments. The device 200 includes an inner inflatable member 203 that elongates to accommodate the additional intermediate body segments 227 of the outer inflatable member 202.

[0102] The device 200 can include a receiving space 211 between the outer inflatable member 202 and the inner inflatable member 203 that is structured similarly to FIG. 2C the receiving space 111 of the device 100 shown.

[0103] The device 200 can also include a proximal coil 204, a distal coil 208, a distal junction 209, and a proximal junction 212 that are structured similarly to FIG. 3C the corresponding components 104, 208, 209, 212 shown in FIG. 5C The device 200 can also include a sleeve, a shaft, and an indicator band that are structured similarly to the corresponding components 105, 106, 107 shown in

[0104] FIG. 6A A close-up view of a portion of the clot retrieval device 200 shown is shown. The portion includes tapered connection arms 230. The connection arms 230 can be shaped as shown and described with respect to FIGS. 1A-5C the tapered connection arms 129, 130 of the device 100 shown. FIG. 6A The connection arms 230 can engage the proximal body segment 226, the intermediate body segments 227, and the distal body segment 228, and can otherwise be structured in a similar manner to FIG. 6A the connection arms 129, 130 of the device 100 shown.

[0105] FIGS. 1A-5C A plan view of a first side of the clot retrieval device 200 is shown. FIGS. 1A-5C A plan view of a second side of the clot retrieval device 200 is shown. FIG. 1A A view of the clot retrieval device 200 shown is shown with the inner inflatable member 203 removed for illustrative purposes. FIG. 6B A view of the clot retrieval device 200 shown is shown with the outer inflatable member 202 removed for illustrative purposes. FIG. 6A A view of the clot retrieval device 200 shown is shown with the outer inflatable member 202 removed for illustrative purposes.

[0106] The outer inflatable member 202 of the device 200 can include a proximal strut 220 and a proximal body segment 226 structured similarly to the proximal strut 120 and the proximal body segment 126 of the device 100 shown. FIGS. 1A-5C The outer inflatable member 202 can include an inlet mouth 222 structured similarly to the inlet mouth 122 of the device 100 shown. FIGS. 1A-5C The outer inflatable member 202 can include a distal body segment 228 structured similarly to the distal body segment 128 of the device 100 shown. FIG. 7A The radiopaque markers 216, 221, 225 can be positioned and otherwise configured in a manner similar to the corresponding markers 116, 121, 125 of the device 100 shown. The outer inflatable member 202 can include an inlet mouth 222 structured similarly to the inlet mouth 122 of the device 100 shown. FIG. 7B The outer inflatable member 202 can include an inlet mouth 222 structured similarly to the inlet mouth 122 of the device 100 shown.

[0107] The inner inflatable member 203 can include distal crown struts 210, interconnected struts 231 in a tubular body portion, and a proximal connecting strut 234 similar to the corresponding struts 110, 131, 138 of the device 100 shown. FIG. 7A The inner inflatable member 203 can include distal crown struts 210, interconnected struts 231 in a tubular body portion, and a proximal connecting strut 234 similar to the corresponding struts 110, 131, 138 of the device 100 shown. FIG. 7C The inner inflatable member 203 can include an inner coil 218 structured similarly to the inner coil 118 of the device 100 shown.

[0108] FIG. 7A A plan view of a second side of the clot retrieval device is shown, the second side being viewed at 90° from the FIGS. 1A-5C A plan view of a second side of the clot retrieval device is shown, the second side being viewed at 90° from the FIGS. 1A-5C A plan view of a second side of the clot retrieval device is shown, the second side being viewed at 90° from the FIGS. 1A-5C A plan view of a second side of the clot retrieval device is shown, the second side being viewed at 90° from the FIGS. 1A-5C A view of the clot retrieval device 200 is shown, with the inner inflatable member 203 removed for illustrative purposes. FIGS. 1A-5C A view of the clot retrieval device 200 is shown, with the outer inflatable member 202 removed for illustrative purposes. FIGS. 1A-5C A view of the clot retrieval device 200 is shown, with the outer inflatable member 202 removed for illustrative purposes.

[0109] FIG. 8A A linear view of the outer inflatable member 202 is shown, cut and flattened along the FIG. 6A and FIG. 7A A linear view of the outer inflatable member 202 is shown, cut and flattened along the FIG. 8B A portion of the outer inflatable member 202 is structured as shown and further as shown. For example, the radiopaque markers 221 can be staggered as shown and as shown in greater detail in FIG. 8A A portion of the outer inflatable member 202 is structured as shown and further as shown. For example, the radiopaque markers 221 can be staggered as shown and as shown in greater detail in FIG. 8C A portion of the outer inflatable member 202 is structured as shown and further as shown. For example, the radiopaque markers 221 can be staggered as shown and as shown in greater detail in FIG. 8A A portion of the outer inflatable member 202 is structured as shown and further as shown. For example, the radiopaque markers 221 can be staggered as shown and as shown in greater detail in FIG. 9 and FIG. 7BThe arm 129 is shown in more detail below. The shape of the struts and joints of the external expandable member 202 is set and otherwise configured to correspond to... FIG. 8B and FIG. 9 The connectors and support bars shown are 144, 145, 146, 147, 150, and 151.

[0110] FIG. 4B A plan view of the distal end of the clot retrieval device 200 is shown. FIG. 4C As shown FIG. 4B The diagram shows a view of the clot retrieval device 200, in which the internal expandable member 203 has been removed for illustrative purposes. FIG. 4B As shown FIG. 4C The diagram shows a view of the clot retrieval device 200, in which the external expandable member 202 has been removed for illustrative purposes.

[0111] FIG. 4B An exemplary external expandable member 302 is shown traversing a lumen with a 360° bend, having a radius of curvature rB at the apex of the bend. Because the external expandable member 302 closely follows the bend of the lumen, it has a radius of curvature approximately equal to the radius of curvature rB of the lumen. FIG. 4C As shown FIG. 10A A close-up of a portion of the external expandable member 302 shown. The external expandable member 302 includes a tapered connecting arm 330 between the main body segments 327, the tapered connecting arm being configured similar to... FIG. 10B The connecting arms 129, 130, and 230 of the devices 100 and 200 shown. FIG. 10A As shown in more detail, the external expandable member 302 has a curvature of radius rA at a narrow region of the connecting arm 330, which is smaller than the total radius of curvature rB of the external expandable member 302 surrounding the bend of the lumen. In other words, the connecting arm 330 provides a bending point for the external expandable member 302. The flexibility of the connecting arm 330 allows the body segment 327 to extend juxtaposed with the lumen (e.g., the lumen and / or vascular lumen shown) to a greater extent than a similarly structured external expandable member with a less flexible connecting arm. In one example, the external expandable member 302 may be configured to bend with a curvature of radius rA of approximately 0.5 mm or greater (including 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1.0 mm) at the narrow region of the connecting arm 330.

[0112] FIG. 10C An illustration of a portion of an exemplary expandable member with transmissive markings is shown. FIG. 10A It shows FIG. 11AA side view of a portion of the expandable member shown. The shapes of some or all of the markings 116, 121, 125, 216, 221, 225 of the apparatus shown and described herein may be similar to... FIG. 11B and FIG. 11A The marker shown.

[0113] FIGS. 1A-10C and FIG. 11B These are radiographic images of an exemplary clot retrieval device according to various aspects of the present invention. The radiopaque material in the distal coil, proximal coil, and marker appears dark in the radiographic images.

[0114] The dimensions of the clot retrieval device according to the teachings of this article can be configured to suit various treatment needs. Dimensions such as the total length L1 of the external expandable member, the working length L2 of the device, the diameter D1 of the external expandable member D1, and the diameter D2 of the internal expandable member can be configured as follows: FIG. 12A and FIG. 12B The measurement is performed as shown.

[0115] In an exemplary device, when freely expanding, the outer expandable member may have a total length L1 of approximately 34 mm, a working length L2 of approximately 22 mm, and a diameter D1 of approximately 5 mm. The diameter D2 of the tubular body of the inner expandable member may be measured to be smaller than the diameter of the outer expandable member, preferably approximately 1 mm, and more preferably approximately 1.22 mm. An exemplary device thus constructed can be suitable for treating blood vessels having a diameter between approximately 1.5 mm and approximately 5 mm. The outer expandable member of the exemplary device preferably comprises... FIG. 12A The device 100 shown has a similar proximal main body section 126, an intermediate main body section 127, and a distal main body section 128, with exactly one intermediate main body section and one distal main body section.

[0116] In another exemplary device, when freely expanding, the outer expandable member may have a total length L1 of approximately 49 mm, a working length L2 of approximately 37 mm, and a diameter D1 of approximately 5 mm. The diameter D2 of the tubular body of the inner expandable member may be measured to be smaller than the diameter of the outer expandable member, preferably approximately 1 mm, and more preferably approximately 1.22 mm. An exemplary device thus constructed can be suitable for treating blood vessels having a diameter between approximately 1.5 mm and approximately 5 mm. The outer expandable member of the exemplary device preferably comprises... FIG. 12A The device 200 shown has a similar proximal main body section 226, intermediate main body section 227 and distal main body section 228, with exactly three intermediate main body sections and a distal main body section.

[0117] In another exemplary device, when freely expanding, the outer expandable member may have a total length L1 of approximately 57 mm, a working length L2 of approximately 45 mm, and a diameter D1 of approximately 6.5 mm. The diameter D2 of the tubular body of the inner expandable member may be measured to be smaller than the diameter of the outer expandable member, preferably approximately 1 mm, and more preferably approximately 1.22 mm. An exemplary device thus constructed can be suitable for treating blood vessels having a diameter between approximately 1.5 mm and approximately 6.5 mm. The outer expandable member of the exemplary device preferably comprises... FIG. 12B The device 200 shown has a similar proximal main body section 226, intermediate main body section 227 and distal main body section 228, with exactly three intermediate main body sections and a distal main body section.

[0118] In some examples, the dimensions of the clot retrieval device according to the teachings herein may be configured such that markers on the main body sections shown herein (e.g., markers 121, 221 on main body sections 126, 127, 128, 226, 227, 228 shown herein) may be separated by approximately 10 mm in the longitudinal direction (in the direction of the longitudinal axis AA) from one or more markers on adjacent main body sections when the clot retrieval device collapses for clot delivery, and may be separated by approximately 8 mm in the longitudinal direction when the clot retrieval device expands freely.

[0119] FIG. 13A An alternative distal portion of an exemplary clot retrieval device is shown, which is described in more detail in a U.S. non-provisional patent application entitled “A CLOT RETRIEVAL DEVICE FOR REMOVING CLOT FROM A BLOOD VESSEL”, filed concurrently with this invention and the entire contents of which are incorporated herein by reference as if fully set forth herein.

[0120] In some examples, the clot retrieval device according to the teachings of this document may have alternative geometries suitable for clot retrieval. For example, the clot retrieval device may include, for instance, FIG. 13B The distal portion of the configuration shown. The external expandable member may include components configured similar to... FIGS. 2A-2C FIGS. 7A-7C FIGS. 1A-5C FIGS. 6A-10C FIGS. 6A-10C FIG. 14 FIG. 14 FIG. 14 The distal body portion 328 shown is the distal body portion. Alternatively, the distal portion of the clot retrieval device does not need to be configured to capture clot fragments and may, for example, have a large unit opening or be fully open. Furthermore, in some examples, the clot retrieval device does not need to include an internal body.

[0121] As discussed herein, a “patient” or “individual” can be a person or any animal. It should be understood that an animal can be any applicable type, including but not limited to mammals, veterinary animals, livestock, or pets. For example, an animal can be a laboratory animal specifically selected to have certain characteristics similar to humans (e.g., rats, dogs, pigs, monkeys, etc.).

[0122] As used herein, the term “about” or “approximately” for any numerical value or range indicates a suitable dimensional tolerance that allows a collection of parts or elements to achieve the intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of enumerated values ​​±20%, for example, “about 90%” may refer to a range of values ​​from 71% to 99%. A range may be expressed herein as “about” or “approximately” for one particular value and / or “about” or “approximately” for another particular value. Other exemplary embodiments when expressing such ranges include from one particular value and / or to another particular value.

[0123] "Comprising," "containing," or "including" means that at least the named compound, element, particle, or method step is present in the composition, article, or method, but does not exclude the presence of other compounds, materials, particles, or method steps, even if the other such compounds, materials, particles, or method steps have the same function as the named ones.

[0124] It should also be noted that, unless the context clearly indicates otherwise, the singular forms “a” and “the” used in this specification and the appended claims include plural references.

[0125] In describing the examples, terminology is used for clarity. Each term is intended to be understood in the broadest sense as grasped by one skilled in the art, and includes all technical equivalents that operate in a similar manner to achieve similar purposes. It should also be understood that reference to one or more steps of a method does not preclude the presence of additional method steps or intermediate method steps between those explicitly identified steps. The steps of a method may be performed in an order different from that described herein without departing from the scope of the disclosed art. Similarly, it should be understood that reference to one or more components in an apparatus or system does not preclude the presence of additional components or intermediate components between those explicitly identified components.

[0126] The description contained herein is exemplary of the present disclosure, and is not intended to limit the scope, applicability or configuration of the disclosure in any way. Various modifications can also be made to the device and methodology described, and the generic principles and specific examples set forth herein apply to other devices and methods in the same field, and not just to the specifics described. For example, while examples described herein relate to particular components, the present disclosure encompasses other examples that implement the described functionality with various combinations of components, with alternative materials, with components of various examples combined, with components of various examples in combination with known components, etc. The present disclosure contemplates substitutions of other well-known and commercially available products for the constituent components shown herein. The scope of the appended claims should not be limited to the specific examples described hereinbefore.

Claims

1. A clot retrieval device, the clot retrieval device comprising a collapsed configuration and an expanded configuration and configured to remove a clot from a blood vessel, the device comprising: An internal expandable member, the internal expandable member including a first support frame; as well as An external expandable member includes a second support frame that forms a closed unit larger than the closed unit of the internal expandable member and at least partially radially surrounds the internal expandable member. The external expandable component includes a first main body section and a second main body section connected by two connecting arms. The first main body segment is positioned relative to the second main body segment along the proximal direction, and Each of the two connecting arms includes a tapered shape, which is wider near the first main body section and narrower near the second main body section. At least one of the first main body segment and the second main body segment includes four or more radiopaque markers circumferentially positioned around the respective main body segment, and wherein when the clot retrieval device is in the collapsed configuration, each of the radiopaque markers is offset and staggered along the longitudinal axis of the device.

2. The clot retrieval device according to claim 1, characterized in that, The external expandable member includes two inlet nozzles in the second support frame, each of the two inlet nozzles including a corresponding opening defined by the first body section, the second body section and the two connecting arms.

3. The clot retrieval device according to claim 2, characterized in that, The first main body segment includes two pairs of support bars, each pair of support bars terminating at a corresponding distal vertex and forming the proximal boundary of the corresponding inlet of the two inlet mouths.

4. The clot retrieval device according to claim 1, characterized in that, The two connecting arms extend substantially parallel to the longitudinal axis of the device.

5. The clot retrieval device according to claim 1, characterized in that, The two connecting arms are positioned about 180° apart from each other around the circumference of the external expandable member.

6. The clot retrieval device according to claim 1, characterized in that, The first main body segment and the second main body segment are connected to each other only via the two connecting arms.

7. The clot retrieval device according to claim 1, characterized in that, When the clot retrieval device is pulled proximally through a tubular vascular system comprising a bend of approximately 180°, each of the two connecting arms is configured to bend at a curvature having a radius smaller than the radius of curvature of most of the struts of the first and second main body sections. This small radius of curvature can have a range of values ​​depending on the tortuosity of the vascular system in which the device expands; when the device is in a straight blood vessel, the radius of curvature will be approximately 0 mm, and when the device is in a blood vessel with a 180-degree bend, the radius of curvature will be approximately 0.5 mm.

8. The clot retrieval device according to claim 1, characterized in that, The external expandable member comprises three or more main body segments, each main body segment having a shape substantially similar to the first main body segment and the second main body segment, and The external expandable member includes a pair of tapered connecting arms, such that each pair of corresponding tapered connecting arms engages longitudinally adjacent body segments of the three or more body segments.

9. The clot retrieval device according to claim 1, characterized in that, When the clot retrieval device is in the collapsed configuration, the alternating radiopaque markers among the four or more radiopaque markers are aligned in a plane orthogonal to the longitudinal axis.

10. The clot retrieval device according to claim 1, characterized in that, The first main body segment includes a first group of four or more radiopaque markers. The second main body segment includes a second group of four or more radiopaque markers. When the clot retrieval device is in the expanded configuration, the first group of four or more radiopaque markers and the second group of four or more radiopaque markers are spaced approximately 8 mm apart in the direction of the longitudinal axis. When the clot retrieval device is in the collapsed configuration, the first group of four or more radiopaque markers and the second group of four or more radiopaque markers are measured to be approximately 10 mm apart in the direction of the longitudinal axis.

11. The clot retrieval device according to claim 1, characterized in that, Each of the four or more radiopaque markers includes radiopaque material positioned within the aperture.

12. The clot retrieval device according to claim 1, characterized in that, At least two of the four or more radiopaque markers are aligned with the corresponding connecting arms of the two connecting arms in the direction of the longitudinal axis.

13. A clot retrieval device, the clot retrieval device comprising a collapsed configuration and an expanded configuration and configured to remove a clot from a blood vessel, the device comprising: An internal expandable member, the internal expandable member including a first support frame; as well as An external expandable member, the external expandable member comprising: A second support frame, the second support frame forming a closed unit larger than the closed unit of the internal expandable member and at least partially radially surrounding the internal expandable member, and Four or more radiopaque markers, attached to the second support frame and positioned to indicate the circumference of the external expandable member, and further positioned such that when the clot retrieval device is in the collapsed configuration, each of the radiopaque markers is offset and staggered along the longitudinal axis of the device. The external expandable member includes discontinuous body segments spaced apart from each other in the direction of the longitudinal axis, the discontinuous body segments including a first body segment and a second body segment, the first body segment being positioned relative to the second body segment in a proximal direction, the external expandable member including two connecting arms that engage the first body segment to the second body segment, and each of the two connecting arms including a tapered shape that is wider near the first body segment and narrower near the second body segment.

14. The clot retrieval device according to claim 13, characterized in that, The four or more radiopaque markers are positioned to indicate the circumference of the body segments in the discontinuous body segments.

15. The clot retrieval device according to claim 13, characterized in that, At least two of the four or more radiopaque markers are aligned with the corresponding connecting arms of the two connecting arms in the direction of the longitudinal axis.

16. The clot retrieval device according to claim 13, characterized in that, The external expandable member includes two inlet nozzles in the second support frame, each of the two inlet nozzles including a corresponding opening defined by the first body section, the second body section and the two connecting arms.

17. The clot retrieval device according to claim 13, characterized in that, The first main body segment includes the four or more radiopaque markers forming the first set of markers, and The second main body segment includes a second group of four or more radiopaque markers, the second group of four or more radiopaque markers being positioned to indicate the circumference of the second main body segment and further positioned such that when the clot retrieval device is in the collapsed configuration, each radiopaque marker in the second group is offset relative to the longitudinal axis of the device from its corresponding adjacent radiopaque marker in the second group.

18. The clot retrieval device according to claim 13, characterized in that, The two connecting arms are positioned about 180° apart from each other around the circumference of the external expandable member.

Images