Blood clot retrieval device for removing blood clots from blood vessels

Abstract

To provide a clot retrieval device for removing a clot from a blood vessel.SOLUTION: The device can include a collapsed configuration and an expanded configuration. The device can include an inner expandable body with a framework of struts. The device can include an outer expandable body with a framework of struts that at least partially radially surround the inner expandable body. A distal portion of the outer expandable body extends in the deployed configuration towards the outer expandable body to a greater extent than the inner expandable body, where closed cells of the distal portion distally taper and are smaller than cells proximal thereto in the outer expandable body. The plurality of closed cells of the distal portion can include a pair of axially aligned smaller diamond shaped cells formed by struts of the distal portion and positioned along upper and lower regions of the distal portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to devices and methods for removing blockages from blood vessels during intravascular medical procedures. [Background technology]

[0002] Clot retrieval devices are used for mechanical clot removal for endovascular interventions, particularly when patients suffer from acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Acute obstructions can include clots, misplaced devices, dislodged devices, large emboli, and the like. Thromboembolism occurs when part or all of a clot detaches from the vessel wall. This clot (referred to herein as an embolus) is then carried in the direction of blood flow. Ischemic stroke can result when a clot lodges in the cerebral vasculature. Pulmonary embolism can result when a clot originates in the venous system or the right side of the heart and lodges in the pulmonary artery or its tributaries. Clots can also develop in the form of emboli, locally blocking blood vessels without being released; this mechanism is common in the formation of coronary artery blockages. Significant challenges exist in designing clot removal devices that can provide high levels of performance. First, there are many access challenges that make device delivery difficult. When access involves navigating the aortic arch (such as in coronary or cerebral occlusions), the shape of the aortic arch in some patients makes it difficult to position a guide catheter. These difficult aortic arch configurations are classified as Type II or Type III aortic arches, with Type III aortic arches presenting the greatest obstacles.

[0003] The problem of tortuosity is even more critical in arteries approaching the brain. For example, it is not uncommon at the distal end of the internal carotid artery for the device to have to progress continuously over several centimeters of blood vessel having 180° bends, 90° bends, and 360° bends. In the case of pulmonary embolism, access is through the venous system and then through the right atrium and right ventricle of the heart. The right ventricular outflow tract and pulmonary artery are delicate blood vessels that can be easily damaged by inflexible or high-profile devices. For these reasons, it is desirable for clot retrieval devices to be compatible with guide catheters that are as low-profile and flexible as possible.

[0004] Second, the vasculature within the region where a blood clot may be lodged is often fragile and delicate. For example, the blood vessels of the neurovascular bundle are more fragile than similarly sized blood vessels in other parts of the body and lie in a soft tissue bed. Excessive tensile forces applied to these blood vessels can result in perforation and bleeding. The pulmonary blood vessels are larger than those of the cerebrovascular system but are also inherently delicate, particularly the more distal pulmonary blood vessels.

[0005] Third, a blood clot can include any of a range of shapes and consistencies. Long, stringy, softer clot material tends to clog at bifurcations or trifurcations, such that multiple blood vessels may be occluded simultaneously over a significant length. More mature and organized clot material may be less compressible than softer, fresher clots and, under the action of blood pressure, can expand the flexible blood vessels in which it is lodged. Further, the inventors have discovered that the properties of a blood clot can be significantly altered by the action of a device that interacts with it. Specifically, compression of a blood clot causes dehydration of the blood clot, resulting in a dramatic increase in both the hardness and coefficient of friction of the blood clot. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] In order for any device to achieve a high level of success in removing blood clots and restoring flow, it is necessary to overcome the problems described above. Existing devices do not adequately address these problems, particularly those associated with vascular trauma and blood clot characteristics.

Means for Solving the Problems

[0007] It is an object of the present design to provide a device and method that meet the above needs. Therefore, it is desirable for a blood clot retrieval device to remove blood clots from the cerebral arteries of patients suffering from AIS, from the native coronary or graft vessels of patients suffering from MI, from the pulmonary arteries of patients suffering from pulmonary embolism, and from other peripheral arteries and veins where blood clots are causing occlusion.

[0008] In some embodiments, a blood clot retrieval device for removing blood clots from blood vessels is disclosed. The device can include a folded configuration and an expanded configuration. The device can include an inner expandable body having a framework of struts. The device can include an outer expandable body that forms closed cells larger than the closed cells of the inner expandable body and that at least partially radially surrounds the inner expandable body. The outer expandable body can include a distal scaffold zone having a plurality of struts that taper distally and have closed cells that are smaller than the cells of its proximal side within the outer expandable body. The plurality of closed cells of the distal scaffold zone include a first plurality of closed cells that are axially aligned and smaller Diamond shape shaped cells formed by the struts of the distal scaffold zone, a second plurality of closed cells that are larger than the cells of the first plurality of closed cells and radially separated, and each smaller Diamond shape shaped cell is located radially inside and distally of each of the second plurality of closed cells, and a third plurality of closed cells that are radially separated and located proximally of each of the second plurality of closed cells.

[0009] In some embodiments, the first plurality of closed cells can include a shape different from that of the second plurality of cells. The second plurality of closed cells can include a shape different from that of the third plurality of closed cells.

[0010] In some embodiments, the distal scaffold zone can be a protective strut structure that includes at least 12 closed cells between the first plurality of closed cells, the second plurality of closed cells, and the third plurality of closed cells.

[0011] In some embodiments, the first plurality of closed cells can include a pair of axially aligned smaller Diamond shape shaped cells formed by struts in the distal portion and positioned along the upper and lower regions of the distal scaffold zone.

[0012] In some embodiments, each Diamond shape shaped cell can have an optimum fit diameter of approximately 1.2 mm.

[0013] In some embodiments, the second plurality of closed cells can include at least 4 cells.

[0014] In some embodiments, at least 4 cells can have an optimum fit diameter of approximately 1.6 mm.

[0015] In some embodiments, each of at least 4 cells can Diamond shape share only one common edge with one of the smaller

[0016] shaped cells. In some embodiments, each of at least 4 cells can be pentagonal.

[0017] In some embodiments, the third plurality of radially separated cells can include at least 5 radially separated cells proximal to the second plurality of cells.

[0018] In some embodiments, the struts of the distal scaffold zone are connected to the inner expandable body.

[0019] In some embodiments, the struts of the distal scaffold zone form a mesh-like structure.

[0020] In some embodiments, the distal scaffold zone can have a porosity greater than the porosity provided by the plurality of struts of the outer expandable body on its proximal side.

[0021] In some embodiments, a clot retrieval device for removing clots from blood vessels is disclosed. The device can include a folded configuration and an expanded configuration. The device can include an inner expandable body having a framework of struts. The device can include an outer expandable body having a framework of struts that at least partially radially surrounds the inner expandable body. The distal portion of the outer expandable body extends distally towards the outer expandable body to a greater extent in the deployed configuration, and the closed cells of the distal portion taper distally and are smaller than the cells on its proximal side within the outer expandable body. The plurality of closed cells of the distal portion are formed by the struts of the distal portion and include a pair of axially aligned smaller Diamond shape shaped cells positioned along the upper and lower regions of the distal portion.

[0022] In some embodiments, the distal portion is a protective strut structure that can include at least 12 closed cells of the plurality of closed cells.

[0023] The plurality of closed cells of the distal portion can include at least four radially separated larger cells, and each smaller Diamond shape shaped cell is radially inward and distally of at least four radially separated larger cells.

[0024] In some embodiments, at least four radially separated larger cells can have an optimum fit diameter of approximately 1.6 mm.

[0025] Each of the at least four radially separated larger cells shares only one common edge with one of the smaller Diamond shape shaped cells.

[0026] In some embodiments, each of the at least four radially separated larger cells forms a pentagon.

[0027] The plurality of closed cells in the distal portion can include at least five radially separated cells proximal to the at least four radially separated larger cells.

[0028] In some embodiments, the framework of the struts of the outer expandable body can include a plurality of discontinuous expandable members spaced apart from adjacent expandable members, and each expandable strut can form at least some struts and closed cells that terminate at a radially separated distal apex without connection to an adjacent closed cell.

[0029] In some embodiments, the device can include a plurality of blood clot inlet openings between respective expandable bodies, and blood clots can pass through the plurality of blood clot inlet openings and enter the device.

[0030] In some embodiments, each member can include at least four radiopaque markers equally radially separated about the longitudinal axis of the outer expandable body.

[0031] In some embodiments, the at least four radiopaque markers are approximately 10 mm apart in the folded configuration.

[0032] In some embodiments, at least four radiopaque markers are spaced approximately 8 mm apart in the expanded configuration.

[0033] In some embodiments, the radiopaque markers of at least four radiopaque markers can include a radiopaque material positioned within the eyelet.

[0034] The radiopaque markers of at least four radiopaque markers can include at least one of barium sulfate, bismuth subcarbonate, barium oxychloride, gold, tungsten, platinum, iridium, tantalum, or an alloy of these materials.

[0035] In some embodiments, the device can include at least three expandable members spaced longitudinally apart.

[0036] In some embodiments, the plurality of closed cells in the distal portion form a distal mesh, the inner expandable body can include a closed distal portion, the distal portion of the outer expandable body is closed, and the distal portions of the outer and inner expandable bodies are configured together to prevent distal exit of blood clots or blood clot fragments from the device.

[0037] In some embodiments, the outer expandable body is expandable to a greater radial extent than the inner expandable body so as to define a blood clot receiving space disposed eccentrically about the longitudinal axis of the outer tubular body.

[0038] In some embodiments, the outer expandable body can include a closed distal portion.

[0039] In some embodiments, the plurality of distal struts of the closed distal portion are helical.

[0040] In some embodiments, the plurality of distal struts of the closed distal portion extend perpendicular to the longitudinal axis of the outer expandable body.

[0041] In some embodiments, the plurality of distal struts of the closed distal portion are configured in a raised or flared pattern.

[0042] In some embodiments, the outer and inner expandable bodies are each a monolithic structure.

[0043] In some embodiments, the outer expandable body can include at least two longitudinally spaced expandable members connected by one or more struts configured as longitudinal hinges between the spaced expandable members, and each expandable member can include a plurality of radially separated radiopaque markers.

[0044] In some embodiments, each marker is positioned at a junction between at least two connecting struts of the respective expandable member.

[0045] In some embodiments, each member can include at least four radiopaque markers equally radially separated about the longitudinal axis of the outer expandable body.

[0046] In some embodiments, the device can include at least three longitudinally spaced expandable members.

[0047] In some embodiments, the radiopaque marker can include a radiopaque material positioned within an eyelet.

[0048] In some embodiments, the radiopaque marker can include at least one of barium sulfate, bismuth subcarbonate, barium oxychloride, gold, tungsten, platinum, iridium, tantalum, or an alloy of these materials.

[0049] In some embodiments, the diameter of the flow path in the expanded configuration is less than 50% of the diameter of the outer expandable body in the expanded configuration along the longitudinally extending blood clot receiving space between the inner expandable body and the outer expandable body.

[0050] In some embodiments, the device can include a shaft extending proximally proximal to the proximal end of the inner and / or outer expandable body.

[0051] In some embodiments, the device can include struts at the distal portion connected to the inner expandable body.

[0052] Other aspects and features of the present disclosure will become apparent to those skilled in the art by considering the following detailed description in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0053] The foregoing and further aspects of the present disclosure will be further considered in conjunction with the following description of the accompanying drawings, in which like numerals in the various drawings indicate like structural elements and features. The drawings are not necessarily to scale, and instead emphasis is placed on illustrating the principles of the present disclosure. The figures depict one or more implementations of the device of the invention by way of illustration and not limitation. Those skilled in the art are expected to be able to envision and combine elements from the plurality of figures to better suit the desires of the user.

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DETAILED DESCRIPTION OF THE INVENTION

[0054] Specific embodiments of the present disclosure are described in detail herein with reference to the drawings, where like reference numerals indicate functionally similar or identical elements. The embodiments address many of the deficiencies associated with conventional catheters, such as inefficient blood clot removal and inaccurate deployment of the catheter to the target site.

[0055] Accessing various blood vessels within the vasculature, regardless of whether they are coronary, pulmonary, or cerebral vessels, involves well-known procedural steps and the use of numerous conventional commercially available accessory products. These products, such as angiographic substances and guidewires, are widely used in diagnostic and medical procedures. When these products are used in conjunction with the systems and methods of the present disclosure in the following description, their functions and exact configurations are not described in detail.

[0056] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and use thereof. Although the description of the present disclosure is often in the context of treating intracranial arteries, the present disclosure can also be used in other body conduits as described above.

[0057] Specific embodiments of the present disclosure have been illustrated and described, and it will be apparent from the above description that various changes can be made without departing from the spirit and scope of the present disclosure. For example, while the embodiments described herein refer to specific features, the present disclosure includes embodiments having combinations of different features. The present disclosure also includes embodiments that do not include all of the specific features described. Specific embodiments of the present disclosure are hereinafter described in detail with reference to the drawings, and the same reference numerals indicate the same or functionally similar elements. The terms "distal" or "proximal" are used in the following description with respect to the position or direction relative to the treating physician. "Distal" or "distally" means a position away from or a direction away from the physician. "Proximal" or "proximally" or "adjacent" means a position close to or a direction toward the physician.

[0058] Accessing the brain, coronary arteries, and pulmonary veins involves the use of a number of commercially available products and conventional treatment procedures. Access products such as guidewires, guide catheters, angiography catheters, and microcatheters are described elsewhere and are routinely used in catheterization procedures. In the following description, these products and methods are assumed to be used in conjunction with the devices and methods of the present disclosure and need not necessarily be described in detail. The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and use thereof. The description of the present disclosure is in many cases in the context of treating intracranial arteries, but the present disclosure may also be used in other body conduits as described above. A common theme throughout many of the disclosed designs is that the device comprises an outer expandable member within which an inner expandable member extends, both members being directly or indirectly connected to an elongate shaft, and having a distal net or scaffold configured to prevent the escape of blood clot fragments formed at the distal end of the device, which is a double-layer structure. This distal net can be attached to any one or some of the shaft, the inner member, or the outer member. As described throughout this document, a range of designs is envisioned for each of these elements, and any of these elements is intended to be used with any other element, but for the sake of avoiding repetition, these elements are not shown in all possible combinations.

[0059] For example, both the inner expandable member and the outer expandable member are desirably made of a material that can automatically recover its shape when released from a significantly distorted delivery configuration. Superelastic materials such as nitinol or alloys with similar properties are particularly suitable. The material can be in many forms such as wire or strip or sheet or tube. A particularly suitable manufacturing process is to laser cut a nitinol tube and then heat treat and electropolish the resulting structure to create a framework of struts and connection elements. This framework can be made into any of a wide variety of shapes as disclosed herein and can be visualized under fluoroscopy through the addition of alloying elements (such as platinum, etc.) or through various other coatings or marker bands. The inner expandable member may, in some cases, form a generally tubular structure and is ideally configured to expand to a diameter smaller than the diameter of the smallest blood vessel it is intended to be used in. This diameter is typically less than 50% of the diameter of the outer expandable member and can be reduced to 20% or less of the outer member diameter. A variety of different distal scaffold zone designs are disclosed, some of which incorporate strut elements from the framework of the outer and / or inner expandable members and some of which incorporate thin wires or fibers to provide additional scaffold while minimizing the impact on the overall device profile or delivery ability. Suitable materials ideally have a high tensile strength such that very thin wires or fibers with sufficient integrity for manufacturability and use can be produced, such as, for example, polymer materials such as UHMWPE, aramid, LCP, PET, or PEN, or metals such as tungsten, MP35N, stainless steel, or nitinol.

[0060] Figure 1 shows one embodiment of a blood clot retrieval device 100 having an outer expandable member 102 and an inner expandable member 103 to facilitate the restoration of blood flow through a blood clot immediately after the device 100 is deployed at the occlusion site. As shown, member 102 can include four expandable members proximal to the distal portion. However, any number of expandable members is contemplated. For example, FIG. 2 shows a modified device 100' having fewer (e.g., two as shown) expandable member portions of member 102. FIG. 3 shows a side view of device 100 without a proximal shaft. Device 100 has an elongated shaft 106 having a distal end that extends into the artery and a proximal end that extends outside the artery. Members 102 and 103 have a folded configuration for delivery and an expanded configuration for blood clot retrieval, blood flow restoration, and fragmentation protection. Member 103 can have a generally tubular body portion.

[0061] Member 103 is configured to self-expand to a diameter larger than the diameter of member 102 upon release from a restraining sheath (e.g., a microcatheter). Expansion of member 102 can cause compression and / or displacement of the blood clot during expansion. When the expandable body provides a high level of scaffold, the blood clot is compressed. When the expandable body provides an escape route or an opening, the expanding body biases the blood clot toward the opening. However, if the expandable body provides only a moderate scaffold, the blood clot is displaced, but because the blood clot has many degrees of freedom, it can move in various different directions and thus cannot be controlled. By providing a tubular expandable body whose length is substantially greater than the length of the occlusive blood clot, many of the degrees of freedom of movement available to the blood clot are removed.

[0062] Members 102 and 103 can specifically have a folded configuration for delivery and an expanded configuration for blood flow recovery and fragmentation protection. Members 102 and 103 can be joined at their proximal and distal ends during assembly to minimize the tension within members 102 and 103 during use. In other embodiments, member 103 may not be connected to the distal end of member 103 at all, or may be constrained within member 102 without being fixedly attached. In other embodiments, member 103 can have a non-cylindrical cross-section, may have a non-uniform diameter, and may have a strut pattern adjusted to provide different radial force or flexibility regions. The length of member 102 may be substantially the same as the length of member 103 in a freely expanded configuration and a loaded folded configuration.

[0063] Member 103 may have an elastic or superelastic or shape memory metal structure and may have a polished surface such as an electropolished surface. Member 103 may be configured to provide a flow lumen or flow path (e.g., having a generally cylindrical cross-section) through device 100 to facilitate the recovery of blood flow passing through the blood clot during deployment. In one embodiment, member 103 is configured to provide a scaffold in the flow path through the blood clot to prevent the detachment of fragments. Otherwise, the detached fragments may clog the distal vascular structure. Member 103 can include one or more connected struts 131 configured to contact the blood clot when first deployed within the target blood vessel within the blood clot. Contact of one or more struts 131 with the blood clot provides additional grip and assists in the initial removal of the blood clot from the blood vessel when device 100 is retracted.

[0064] The distal end of member 103 can include an expandable portion formed from an expanded strut 110 having a diameter larger than the diameter of member 103. These expanded struts 110 can be connected to a coil portion 118 (see, e.g., FIG. 8) that can be laser cut from a tube that can also cut member 103. Coil 118 can also be configured to accommodate small length differences by stretching without applying significant tensile or compressive forces to device 100. Coil 118 can be formed from a stainless steel material, a polymer, or a more radiopaque metal such as gold or platinum, or an alloy of such materials. Coil 118 can be replaced by the longitudinal length of an elastic material such as a low modulus polymer or elastomer. The distal end of coil 118 can be joined to the distal collar 109 of member 102 (e.g., by an adhesive, soldering, welding, or brazing process). In some embodiments, struts 110 can be capable of elongating during loading, such that the lengths of members 102, 103 may be equal when fully loaded within the microcatheter. The length difference between member 102 and member 103 can still occur when device 100 is deployed within a small blood vessel or during the loading or deployment process.

[0065] Members 102 and 103 are preferably made of a superelastic or pseudoelastic material such as nitinol or another such alloy having a high recoverable strain. The shaft 106 may be a tapered wire shaft and may be made of stainless steel, MP35N, nitinol, or other materials suitably having a high elastic modulus and tensile strength. The shaft 106 may have an indicator band 107 to indicate when the distal end of the device 100 is approaching the end of the microcatheter during insertion. The shaft 106 can have a coil 104 adjacent to its distal end and proximal to the members 102, 103. The coil 104 may be metallic and may be formed of stainless steel, or a more radiopaque material such as, for example, platinum or gold, or an alloy of such materials. In another embodiment, the coil 104 may be coated with a low friction material or may have a polymer jacket positioned on the outer surface of the coil 104. Adjacent to the coil 104, a sleeve 105 may be positioned on the shaft 106. The sleeve 105 may be polymeric and may be positioned over the tapered portion of the shaft 106. The sleeve 105 can be made radiopaque by adding a filling material such as tungsten or barium sulfate. However, other radiopaque materials are contemplated including, but not limited to, bismuth subcarbonate, barium oxychloride, gold, platinum, iridium, tantalum, or an alloy of any of these materials. The sleeve 105 and the shaft 106 may be coated with a material that reduces friction and thrombogenicity. The coating may include a polymer, a low friction lubricant such as silicone, a hydrophilic or hydrophobic coating. This coating may also be applied to the members 102 and the member 103.

[0066] Figure 4A shows a side view of the member 102, and Figure 4B shows a plan view of the member 102. An inlet opening 122 is provided in the member 102, whereby the inlet 122 can provide the main degree of freedom of movement available to the blood clot, so that upon expansion of the member 102, the blood clot is biased into the receiving space 111. The member 102 can have a plurality of inlet openings 122 for receiving the blood clot. The inlet opening 122 may be configured to allow a portion of the blood clot to enter the receiving space 111, and thus be able to recover the blood clot without being overly compressed. This is advantageous because the inventors have discovered that compression of the blood clot dehydrates the blood clot, but then the frictional properties of the blood clot increase and its rigidity increases, all of which make it more difficult for the blood clot to detach from and be removed from the blood vessel. This compression can be avoided when the blood clot moves inward through the wall of the member 102 as the porous structure moves outward toward the blood vessel wall.

[0067] The inlet opening 122 can also provide an additional benefit in that when the member 102 is retracted, the member 102 can apply a force to the blood clot in a direction substantially parallel to the direction in which the blood clot is pulled from the blood vessel (i.e., substantially parallel to the central axis of the blood vessel). This means that the outward radial force applied to the vasculature can be minimized, and thus the action of the blood clot retrieval device 100 on the blood clot will not increase the force required to remove the blood clot from the blood vessel, and as a result, protect the delicate cerebral blood vessels from harmful radial and tensile forces.

[0068] As shown, member 102 can include a proximal strut 120 that is connected to a collar 112 at its proximal end and to a first expandable member 126 at its distal end, which is more clearly shown in FIG. 6 at section B-B. The strut 120 may have a tapered profile to ensure a gradual stiffness transition from the shaft 106 to the blood clot engaging portion of the device. Member 126 can be connected to a second expandable member 127 by a plurality of connection arms 129 that can extend from a proximal joint 139 to a distal joint 140. The arms 129 can include generally linear struts that extend parallel to the central axis of the device. In other embodiments, these connection arms may comprise a plurality of struts configured in one or more cells, or may comprise curved or helical arms. The region between the first expandable member and the second expandable member includes two inlet openings 122 through which a blood clot can pass and enter a receiving space 111 defined by the region between the inner and outer members.

[0069] Member 127 can then be connected to a third expandable member 128 by a connection arm 130 that extends from a proximal joint 141 to a distal joint 142. The arm 130 can include generally linear struts that extend parallel to the central axis of the device 100. In other examples, the arm 130 may comprise a plurality of struts configured in one or more cells, or may comprise curved or helical arms. The region between members 127 and 128 can include one or more inlet openings 122 through which a blood clot can pass and enter the receiving space 111 defined by the region between members 102 and 103. The arm 129 between members 126 and 127 can be substantially aligned with the arm 130 between members 127 and 128 to align the neutral axes of members 126, 127, and 128 during flexion. In other examples, the arm 129 between members 126 and 127 may be aligned at an angle, such as 90 degrees, with the arm 130 between members 127 and 1

[0070] In some embodiments, member 126 can include interconnected struts such as strut 143 that terminates at crown 133 without a distal connection element, and other struts such as 144 that terminate at junctions 145 and 146. The struts within the expandable member can be configured such that during loading, multiple crowns (e.g., crowns 145, 150) are not aligned at the same distance from the proximal collar 112. During loading or re-sheathing, generally more force may be required to load the crowns into the sheath than the struts. Thus, if multiple crowns are loaded simultaneously, the user may notice an increase in the loading force. By offsetting the crowns (e.g., crowns 145, 150) by making alternative struts 144 and 151 different lengths, the loading force can be reduced and the perception for the user is improved. Similarly, the second expandable member 127 can include interconnected struts such as strut 147 that terminates at crown 134 without a distal connection element, and other struts (e.g., strut 148) that terminate at junctions. Similarly, the third expandable member 128 can include interconnected struts such as strut 152 that terminates at crown 135 without a distal connection element, and other struts that terminate at junctions. FIG. 7 shows a cross-sectional view of section C-C of FIG. 3 that more clearly shows member 128 and its struts (e.g., strut 152) and crown 135. As shown, fewer or more expandable members 126, 12, 128 may be included in member 102.

[0071] In some embodiments, the expandable member of member 102 may include one or more markers 125 having a radiopaque material such as, but not limited to, radiopaque materials such as gold, tungsten, tantalum, platinum, or alloys containing these or other elements of large atomic numbers. Polymer materials (e.g., polyurethane, pebax, nylon, polyethylene, etc.) containing radiopaque fillers such as barium sulfate, bismuth subcarbonate, barium oxychloride, gold, tungsten, platinum, iridium, tantalum, alloys of these materials, and / or adhesives filled with radiopaque fillers may also be used. In this regard, marker 125 may be included as an eyelet on the strut throughout member 102. Marker 125 may be positioned to indicate to the user the distal end of the body of member 102 in order to assist with the accuracy of deployment. The distal end of member 102 may include a circumferential ring of struts 123 connected to a series of struts 124 that can terminate at a distal junction point 109 that can include a color. In some embodiments, member 102 can terminate with a closed distal end, and in other aspects, the distal end of member 102 may be open or not necessarily closed. In some embodiments, struts 124 may generally have a conical shape as shown. In some embodiments, struts 124 may be generally configured in a plane, which may be inclined or perpendicular to the longitudinal axis of device 100. Struts 124 and 149 can taper to a width narrower than that of the more proximal struts, including the body of the expandable member (e.g., members 126, 127, 128, etc.), and thus can create a gradual transition in the rigidity of the device in both the expanded and folded states.

[0072] FIG. 5 is an enlarged view of section A-A of FIG. 1, more clearly showing exemplary marker 125 disposed on and shifted along member 126. The positions of marker 125 shown in FIG. 7 and throughout the present disclosure are merely exemplary, and it is understood that marker 125 may be included in other locations and other features of device 100. In some embodiments, marker 125 may be approximately 10 mm apart in the folded delivery configuration and approximately 8 mm apart in the expanded configuration. However, marker 125 is not so limited and can be separated as needed or required.

[0073] FIG. 8 shows an enlarged view of section D-D of FIG. 3, more clearly showing distal region 155, and FIG. 9 shows an enlarged isometric view of distal region 155 of device 100 in section E-E of FIG. 3 (which may also be referred to interchangeably herein as the distal scaffold zone). FIGS. 10A (end view) and 10B (isometric view) show only the distal region 155 of member 102, where the three-dimensional distal mesh of region 155 is configured to be generated by the strut framework of the fragment protection feature. As shown, the plurality of vertices or crowns 184 of distal region 155 shown in FIGS. 9-10C are provided connected to the plurality of proximal arms 182 thereof, which terminate at a junction proximate to color 109. Arms 182 may be shaped as needed or required, including generally arcuate or conical as shown. Preferably, arms 182 form a plurality of closed cells that progress gradually from a larger closed cell at or adjacent to the proximal end of region 155 to a smaller closed cell at or adjacent to the distal end thereof. In some embodiments, at least 12 closed cells may be provided within distal region 155 of device 100. The illustrated distal region 155 can include the closed distal end of member 102, which, together with the mesh formed by arms 182 and corresponding closed cells of region 155, can prevent the exit of blood clots or blood clot fragments that have entered the aforementioned receiving space 111 between members 102 and 103.

[0074] In some embodiments, smaller axially aligned Diamond shape cells 187 may be formed by arms 182 and positioned along upper and lower regions of the distal mesh. In some embodiments, at least two cells 187 are provided. Larger cells 189 may be positioned radially about the longitudinal axis L of the device 100 and radially inward of cells 187. In some embodiments, at least four cells 189 are provided joined at or adjacent to the junction proximate color 109. In some embodiments, cells 189 may be approximately 1.2 mm in size, this measurement being the size of the best fit diameter of a circle disposed within each cell (e.g., the illustrated cell 187 depicted in the plan view of FIG. 10C). In other embodiments, cells 189 may be larger (e.g., approximately 1.6 mm).

[0075] Cells 186 may also be provided proximal to cells 187, 189. In some embodiments, at least five cells 186 radially separated about axis L may be positioned proximal to cells l87, l89. Each of cells 186 can include struts common to cells 187, 189, and crown 184. In some embodiments, the proximal strut of each of cells 186 may be arcuate or otherwise curved. In some embodiments, the distal region 155 of FIGS. 9-10C shown may be a monolithic structure integrally formed with the region of its proximal member 102 (e.g., by laser machining from the same tube as the remainder of member 102). In some embodiments, a radiopaque coil 108 (e.g., formed of platinum, gold, alloy, etc.) may be positioned distal to the distal region 155 configured to couple to or with distal color 109.

[0076] FIG. 11A shows an enlarged isometric view of an exemplary marker 125, and FIG. 11B shows a side view of the marker 125. The illustrated marker 125 is generally formed of platinum-iridium, but as noted above, other radiopaque materials are contemplated as needed or required.

[0077] FIG. 12 shows an enlarged view of an expandable member 127 in a folded configuration showing an exemplary laser cut pattern having enhanced visibility. It is understood that other expandable members of member 102 can follow the same or similar pattern. Member 12 may include three eyelet cutouts offset for marker 125. In other embodiments, member 12 may include four eyelet cutouts offset for marker 125. Fewer or more eyelet cutouts can be included as needed or required to incorporate marker 125. In those embodiments having four eyelet cutouts, each expandable member of member 102 can include four markers 125. In this regard, if member 102 had three expandable members, member 102 could include a total of at least 12 markers 125 offset throughout. If member 102 had four expandable members, at least 20 markers 125 may be included in member 102 offset throughout.

[0078] The present disclosure is not limited to the described embodiments, which can vary in configuration and detail. The terms "distal" and "proximal" are used throughout the foregoing description and are meant to refer to the position and direction relative to the treating physician. Thus, "distal" or "distally" refers to a position away from or a direction away from the physician. Similarly, "proximal" or "proximally" refers to a position near or a direction toward the physician.

[0079] In the description of the embodiments, technical terms are used for the sake of clarity. Each term is intended to have the broadest meaning understood by those skilled in the art and is intended to include all technical equivalents that act in a similar manner to achieve similar purposes. It should also be understood that a reference to one or more steps of a method does not exclude the presence of additional method steps or method steps intervening between those explicitly identified. Each step of the method can be performed in an order different from the order described herein without departing from the scope of the disclosed technology. Similarly, a reference to one or more components in a device or system should be understood not to exclude the presence of additional components or components intervening between those explicitly identified.

[0080] As used herein, "patient" or "subject" can be a human or any animal. It should be understood that the animal can be of any of a variety of applicable types, including but not limited to mammals, veterinary animals, livestock animals, or pet animals. By way of example, the animal can be an experimental animal (e.g., rat, dog, pig, monkey, etc.) specifically selected to have certain properties similar to humans.

[0081] As used herein, the term "about" or "approximately" with respect to any numerical value or range of numerical values indicates a tolerance of suitable dimensions that allows a component or collection of components to function in accordance with its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of values that are ±20% of the recited value. For example, "about 90%" can refer to a range of values from 71% to 99%. Ranges can be expressed herein as from one specific value of "about" or "approximately" to another specific value of "about" or "approximately". When representing such ranges, other exemplary embodiments also include from one specific value to another specific value.

[0082] As used herein, the terms "comprising", "containing", or "including" mean that at least the specified compound, element, particle, or method step is present in a composition, article, or method, but do not exclude the presence of other compounds, materials, particles, or method steps, even if they have the same function as the specified ones.

[0083] It should also be noted that in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0084] The descriptions contained herein are examples of the present disclosure and are not intended to limit the scope of the present disclosure in any way. Although specific embodiments of the present disclosure are described, various modifications can be made to the devices and methods without departing from the scope and spirit of the present disclosure. For example, the embodiments described herein refer to specific components, but the present disclosure may utilize various combinations of components to achieve the described functionality, utilize alternative materials to achieve the described functionality, combine components from various embodiments, combine components from various embodiments with known components, etc. The present disclosure contemplates replacing the component parts illustrated herein with other well-known commercially available products. Such modifications will be apparent to those skilled in the art in many cases and are intended to be within the scope of the following claims.

[0085] 〔Embodiments〕 (1) A blood clot retrieval device for removing blood clots from blood vessels, the device having a folded configuration and an expanded configuration, and an inner expandable body having a framework of struts, An outer expandable body comprising a framework of struts that forms closed cells larger than the closed cells of the inner expandable body and at least partially surrounds the inner expandable body radially, the outer expandable body comprising a distal scaffold zone having a plurality of struts that taper distally and have closed cells smaller than their proximal cells within the outer expandable body, and an outer expandable body, wherein the plurality of closed cells of the distal scaffold zone are a first plurality of closed cells that are smaller axially aligned cells formed by the struts of the distal scaffold zone Diamond shape in a shape, and a second plurality of closed cells that are larger than the cells of the first plurality of closed cells and are radially separated, each smaller Diamond shape a second plurality of closed cells in a shape, wherein each smaller cell is radially inside and distally of each of the second plurality of closed cells, [[ID=S12]]a third plurality of closed cells that are radially separated and proximal to each of the second plurality of closed cells, a blood clot collection device. (2) The device according to embodiment 1, wherein the first plurality of closed cells have a shape different from that of the second plurality of cells, and the second plurality of closed cells have a shape different from that of the third plurality of closed cells. (3) The device according to embodiment 1, wherein the distal scaffold zone is a protective strut structure having at least 12 closed cells between the first plurality of closed cells, the second plurality of closed cells, and the third plurality of closed cells. (4) The device according to embodiment 1, wherein the first plurality of closed cells are formed by struts in the distal portion and are a pair of axially aligned smaller Diamond shape cells in a shape positioned along the upper and lower regions of the distal scaffold zone. (5) The device according to embodiment 4, wherein each Diamond shape cell in a shape has an optimal fit diameter of approximately 1.2 mm.

[0086] (6) The device according to embodiment 4, wherein the second plurality of closed cells comprises at least four cells. (7) The device according to embodiment 6, wherein the at least four cells have an optimum fit diameter of approximately 1.6 mm. (8) Each of the at least four cells shares only one common edge with one of the smaller Diamond shape shaped cells. The device according to embodiment 6. (9) Each of the at least four cells is pentagonal. The device according to embodiment 6. (10) The device according to embodiment 6, wherein the third plurality of radially separated cells includes at least five radially separated cells proximal to the second plurality of cells.

[0087] (11) A blood clot retrieval device for removing a blood clot from a blood vessel, the device comprising a folded configuration and an expanded configuration, and an inner expandable body having a framework of struts, an outer expandable body having a framework of struts that at least partially surrounds the inner expandable body radially, a distal portion of the outer expandable body extending towards the outer expandable body to a greater extent than the inner expandable body in a deployed configuration, the closed cells of the distal portion tapering distally and being smaller than the cells on its proximal side within the outer expandable body, the plurality of closed cells of the distal portion being formed by the struts of the distal portion and including a pair of axially aligned smaller Diamond shape shaped cells positioned along an upper region and a lower region of the distal portion. A blood clot retrieval device. (12) The device according to embodiment 11, wherein the distal portion is a protective strut structure comprising at least twelve of the plurality of closed cells. (13) The plurality of closed cells of the distal portion includes at least four radially separated larger cells, each smaller Diamond shapeThe device according to embodiment 11, wherein the shaped cells are radially inner and distal to the at least four radially separated larger cells. (14) The device according to embodiment 13, wherein the at least four radially separated larger cells have an optimally fitting diameter of approximately 1.6 mm. (15) Each of the at least four radially separated larger cells of the device according to embodiment 13 shares only one common edge with one of the smaller Diamond shape shaped cells.

[0088] (16) The device according to embodiment 13, wherein each of the at least four radially separated larger cells is pentagonal. (17) The device according to embodiment 13, wherein the plurality of closed cells in the distal portion includes at least five radially separated cells proximal to the at least four radially separated larger cells. (18) The framework of the struts of the outer expandable body of the device according to embodiment 11 comprises a plurality of discontinuous expandable members spaced apart from adjacent expandable members, each expandable strut forming at least some struts and closed cells that terminate at a radially separated distal apex without connection to an adjacent closed cell, and each member comprising at least four radiopaque markers equally radially separated about the longitudinal axis of the outer expandable body. (19) The device according to embodiment 18, wherein the at least four radiopaque markers are spaced approximately 10 mm apart in the folded configuration. (20) The device according to embodiment 18, wherein the at least four radiopaque markers include at least one of barium sulfate, bismuth subcarbonate, barium oxychloride, gold, tungsten, platinum, iridium, tantalum, or an alloy of these materials.

Claims

1. A clot retrieval device for removing clots from blood vessels, the device comprising a folded configuration and an expanded configuration, and an inner expandable body comprising a framework of struts, an outer expandable body forming closed cells larger than the closed cells of the inner expandable body and comprising a framework of struts that at least partially radially surrounds the inner expandable body, the outer expandable body comprising a distal scaffold zone having a plurality of struts that taper distally and have closed cells smaller than the cells proximal thereto within the outer expandable body, wherein the plurality of closed cells of the distal scaffold zone comprise a first plurality of closed cells that are axially aligned smaller diamond-shaped cells formed by the struts of the distal scaffold zone, a second plurality of closed cells that are larger than the cells of the first plurality of closed cells and are radially separated, each smaller diamond-shaped cell being radially outside and proximal to each of the second plurality of closed cells, a third plurality of closed cells that are radially separated and are proximal to each of the first plurality of closed cells and each of the second plurality of closed cells, a clot retrieval device.

2. wherein the first plurality of closed cells have a different shape from the second plurality of cells, the device according to claim 1, wherein the second plurality of closed cells have a different shape from the third plurality of closed cells.

3. The device according to claim 1, wherein the total number of the first plurality of closed cells, the second plurality of closed cells, and the third plurality of closed cells is at least 12.

4. the device according to claim 1, wherein the first plurality of closed cells are a pair of axially aligned smaller diamond-shaped cells formed by struts in the distal portion and positioned along the upper and lower regions of the distal scaffold zone.

5. The device according to claim 4, wherein each diamond-shaped cell has an optimum fit diameter of approximately 1.2 mm.

6. The device according to claim 4, wherein the second plurality of closed cells comprise at least 4 cells.

7. The device according to claim 6, wherein the at least 4 cells have an optimum fit diameter of approximately 1.6 mm.

8. The device according to claim 6, wherein each of said at least four cells shares only one common edge with one of said smaller diamond-shaped cells. **Claim 9** The device according to claim 6, wherein each of said at least four cells is pentagonal. **Claim 10** The device according to claim 6, wherein said third plurality of radially separated cells includes at least five radially separated cells proximal to said second plurality of cells.

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