Rotating frame type thrombus removal device

Abstract

To provide a device for removing a clot from a vessel.SOLUTION: The device for removing a clot from a vessel can have dual layers where an inner expandable body runs within an outer expandable body. The device can have a collapsed delivery configuration, an expanded deployed configuration, and a clot pinching configuration. The inner and outer bodies can be a plurality of cells formed by a network of struts. Openings of the cells align when the device is deployed into the clot, where the radial force from the expanding bodies urges respective portions of the clot through the openings. The inner and outer bodies can be configured to be selectively translatable relative to each other, so that the respective portions of the clot in the cell openings can be compressed and gripped when the translation transitions the device to the clot pinching configuration. The translation can be maintained to pinch the clot as the clot is retrieved from the patient.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to devices and methods for removing acute occlusions from blood vessels during intravascular medical procedures. More specifically, the present disclosure relates to a clot retrieval device for removing blood clots from blood vessels.

Background Art

[0002] The present disclosure relates to devices and methods for removing acute occlusions from blood vessels. Acute occlusions can include blood clots, misplaced devices, migrated devices, large emboli, and the like. Thromboembolism occurs when part or all of a blood clot detaches from the vessel wall. This blood clot (herein referred to as an embolus) is then carried in the direction of blood flow, which can cause numerous complications. Ischemic stroke can result when a blood clot lodges in the cerebral vasculature. Pulmonary embolism can result when a blood clot forms in the venous system or on the right side of the heart and lodges in the pulmonary artery or its branches. Blood clots can also develop in the form of emboli without being released and locally occlude blood vessels, a mechanism that is common in the formation of coronary artery obstructions. The devices and methods herein are particularly suitable for removing blood clots from the major cerebral arteries of patients suffering from acute ischemic stroke (AIS), from the pulmonary arteries of patients suffering from pulmonary embolism (PE), from native or transplanted coronary vessels of patients suffering from myocardial infarction (MI), and from other peripheral arteries and veins where blood clots are causing occlusions.

[0003] There are many challenges related to access that can make it difficult to deliver a device to the target site. When access involves navigating the aortic arch (such as in coronary artery occlusion or cerebral occlusion), the shape of the aortic arch in some patients makes it difficult to position a guide catheter. The problem of tortuosity is even more severe in arteries approaching the brain. At the distal end of the internal carotid artery, it is not uncommon for a device to have to advance through a vascular segment with several bends in succession over a movement of only a few centimeters. In the case of pulmonary embolism, access can be obtained 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 a clot retrieval device to be compatible with access catheters and support catheters that are as low-profile and flexible as possible.

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

[0005] Stent-like clot retrieval devices are increasingly being used to remove clots from the cerebral blood vessels of acute stroke patients. These devices often rely on a pinning mechanism that grips the clot by capturing it between a self-expanding stent-like body and the vessel wall. This approach has many drawbacks.

[0006] The stent-like blood clot retriever maintains its gripping force on the blood clot during retraction, depending on its outward radial force. This compressive force tends to dehydrate the blood clot, which in turn can increase its coefficient of friction and make it more difficult to expel and remove the blood clot from the blood vessel. If the radial force is too small, the stent-like blood clot retriever loses its gripping force on the blood clot, but if the radial force is too large, the stent-like blood clot retriever may damage the blood vessel wall and may require an overly strong force to withdraw. Thus, a stent-like blood clot retriever having a radial force sufficient to handle all blood clot types may cause vascular trauma and serious patient injury, and a stent-like blood clot retriever having a radial force appropriate to maintain non-traumaticity may not be able to effectively handle all blood clot types in diverse thrombectomy situations. Pinching the blood clot between the stent-like blood clot retriever and the blood vessel wall also results in high shear forces on the sides of the blood clot when the blood clot is removed, and in some cases, fragments of the blood clot will be released. If these fragments are not retained by the device, they can migrate and cause further occlusion in the distal vasculature.

[0007] Certain conventional stent-like blood clot retriever designs also do not hold their expanded shape well when placed under tension within the curvature of a blood vessel due to the way their strut elements are connected to each other, such that the struts remain under tension even during retraction. This tension is due to the friction between the device and the blood vessel and increases when additional loading, such as loading due to resistance provided by the blood clot, is present. This can result in a decrease in the gripping force on the blood clot when the stent-like blood clot retriever is withdrawn proximally around the curvature of a tortuous blood vessel, with the potential for the captured blood clot to slip out. At the curvature, the struts on the outside of the curvature are placed under higher tension than the struts on the inside. To achieve the lowest possible energy state, the outer surface of the blood clot retrieval device moves towards the inner surface of the curvature, thereby reducing the tension in the struts but also decreasing the expanded diameter of the device.

[0008] Furthermore, when attempting to remove a long blood clot, conventional devices that are shorter than the blood clot are highly likely to be unable to restore the flow through the occluded area during deployment. As a result, the pressure gradient across the entire blood clot remains a significant obstacle to blood clot removal. Simply making such a device longer makes it difficult to track through tortuous anatomical structures, can cause trauma to the vasculature, requires more force to withdraw, and in some cases may render the device immovable, potentially necessitating surgery to remove it.

[0009] The steerability of a given device is also important for many reasons, as physicians often need to make multiple passes to completely remove an occlusion. Each time the blood clot retrieval device is withdrawn, access to the target site is lost. Therefore, it may be necessary to re-advance the guidewire and microcatheter to access the blood clot, re-cross it, then remove the guidewire and advance the blood clot retrieval device through the microcatheter. Guiding the guidewire and microcatheter to the blood clot can be quite time-consuming, especially if the blood vessels are tortuous. This additional time and device manipulation increase the risk of complications to which the patient is exposed, highlighting the importance of an effective and efficient device.

[0010] When determining the treatment efficiency in this environment, in many cases, a device having a number of bodies is preferred. Such a device may have an outer body that can be scaffolded to the target blood vessel and an inner body for enclosing and capturing blood clots. These devices can function well in engaging with and expelling blood clots, but having a larger and in many cases more rigid network of struts can make it more difficult in some cases to retract the device and partially or fully fold it to re-sheath the device within the outer catheter. Since these devices are designed such that blood clots are typically required to move through the outer member, the outer member may not have a very strong gripping force on the peripheral region of the blood clot. Due to the larger expanded shape of the outer body, as a result, when the device is partially or fully folded during retraction, the outer body struts may collide with or deflect the struts of the inner body.

Summary of the Invention

Problems to be Solved by the Invention

[0011] In order for any device to achieve a high level of success in removing blood clots, restoring blood flow, and facilitating good patient outcomes, it is necessary to overcome the problems described above. The present design aims to provide an improved blood clot retrieval device that addresses the above deficiencies.

Means for Solving the Problems

[0012] The disclosed design for a clot retrieval device solves these problems by providing a dual-layer device in which the inner and outer members work cooperatively to capture the entire clot along the entire length of the device. This design can feature a deployed configuration in which both the inner and outer members have large cell openings that are aligned to allow an applied radial force to displace the clot through the openings when the device is expanded. One of the members can then be translated relative to the other, causing the aligned cell openings to close and compressively sandwich the clot between the opposing edges of the cells of the inner and outer members. This action improves the device's grip on the clot during all stages of retrieval, allowing for safer and more efficient blood flow restoration.

[0013] The device can have a collapsed delivery configuration when constrained within an outer catheter and an expanded, clot-engaging deployment configuration when deployed at a target site. The device can have an elongate shaft for independent manipulation. The shaft can connect to a framework of struts forming an expandable member extending distally from the shaft. The elongate shaft can feature a first shaft and a second shaft that is translatable and / or rotatable relative to the first shaft. These shafts can be used by a user to control and activate the function of the expandable member during a procedure.

[0014] The expandable member may have a bilayer structure having an inner body connected to a second shaft and an outer body connected to a first shaft. The bodies may enclose a substantially tubular inner lumen and a longitudinal axis extending therethrough. The properties of the inner and outer bodies may be adjusted independently of one another. The outer body may be coaxial with the inner body or may be radially offset from the inner body. The inner body may be disposed substantially within the lumen of the outer body.

[0015] The inner body can have a plurality of cells and can be translatable relative to the outer body about a longitudinal axis. The outer body can also have a plurality of closed cells and can have a radial size that is larger than the radial size of the inner body when in an expanded deployment configuration and can be configured to support juxtaposed to the wall of the target vessel. The outer body can also be translatable relative to the inner body about a longitudinal axis. By translation, the device can be transitioned between an expanded deployment configuration and a blood clot clamping configuration.

[0016] The cells of the inner and outer bodies of the expandable member may be substantially equal in size or they may be sized differently such that there is some overlap between the cell boundaries. When deployed into an expanded configuration across a blood clot at the target site, the struts of the cells of the inner and outer bodies engage the blood clot by exerting a radial force to compress the blood clot against the vessel wall and can dig into the blood clot. The cells of the inner and outer bodies can be aligned such that as a result of this compression, at least a portion of the blood clot is biased to move radially inwards towards the inner tubular lumen through the cells. The radial force exerted by the outer member may be greater than, less than, or in other examples, substantially equal to the radial force exerted by the inner member.

[0017] The cells of the inner body and the cells of the outer body may offset when the user translates the inner body or the outer body relative to each other, such as by using the first shaft and the second shaft. The translation may be linear along the longitudinal axis, a rotation about an axis, or a combination thereof. The translation can compress and clamp a blood clot between struts of the offset cells of the body when transitioning the device from an expanded configuration with relative movement extended to a blood clot clamping configuration. This clamping within the cells contracts each portion of the blood clot so that it is firmly held when the device is retracted from the target site. The relative translation between the inner body and the outer body can also be maintained when the blood clot is withdrawn, such that the device remains in the blood clot clamping configuration and the gripping force is not lost.

[0018] The translation of the parallel movement of the inner body and the outer body for the blood clot clamping structure can be actuated via the first shaft and the second shaft of the device. For example, the first shaft can have an elongated tubular body having an internal lumen and a slot passing through a wall thickness substantially equal to its distal end. The second shaft may be a cylindrical member disposed within the lumen of the first shaft, such that the two shafts are movable relative to each other. An index pin can extend radially outward from the outer surface of the second shaft, thereby engaging a slot within the first shaft and configured to move within the extent of that slot. The index pin and the slot can be sized such that the circumferential rotation and / or axial movement of the pin (and thus the inner shaft and the inner body) is guided over the entire length of the slot. The orientation of the slot may, for example, be parallel to the longitudinal axis, or the axis of the slot may be oriented to form an angle with the longitudinal axis of the device. Then, when the user pushes or pulls the elongated body of the inner shaft along the axis of the shaft, the index pin can receive movement along the slot axis, enabling rotation and translation of the inner shaft and inner body relative to the outer shaft and outer body. This movement can offset the cells of the inner body and the cells of the outer body in order to clamp and firmly grip the blood clot. This process may also be reversed to transition the device from the blood clot clamping configuration back to the deployed configuration expanded from it.

[0019] In another example, the inner body may have an inner support arm joined to the second shaft, and the outer body may have an outer support arm joined to the first shaft. These support arms may be formed at an angle such that they can be twisted about the longitudinal axis. Then, the tangential force on the inner support arm or the outer support arm can affect the relative twist on the inner body and / or the outer body of the device when the outer catheter or the access catheter is advanced over the device. This relative twist can cause the translation necessary to clamp and firmly grip the blood clot.

[0020] In another example, a device for treating a blood clot or occlusion within a body vessel may have a tubular inner lumen configured about a longitudinal axis. The device may have an inner body comprising a constrained delivery configuration, an expanded deployment configuration, and a plurality of struts forming a porous inner blood clot scaffold section. An outer body may be disposed about the inner body and may share the constrained delivery configuration and the expanded deployment configuration. The outer body may also be porous by a plurality of interconnected struts forming an outer blood clot scaffold section. A slender shaft may extend proximal to the inner and outer bodies to enable a user to control and manipulate the device.

[0021] The struts of the scaffold sections of the inner and outer bodies may form rings of open cells or closed cells. The cells may be of substantially equal size or of different sizes. The cells of the inner body may align with the cells of the outer body when the device is delivered from the constrained delivery configuration and expands to the deployment configuration at the target site. Expansion of the scaffold struts may exert an outward radial force on the blood clot or occlusion, driving the struts of the scaffold section into the blood clot and promoting movement and protrusion of portions of the blood clot radially inwardly through the openings of the aligned cells and toward the inner tubular lumen.

[0022] The inner body and the outer body may be translatable relative to each other about the longitudinal axis. This translation may be activated by the user through the operation of an elongate shaft. The shaft may have a first shaft attached to the outer body that surrounds a second shaft connected to the inner body such that the first shaft and the second shaft are translatable relative to each other. In this way, when the user translates and / or rotates the inner second shaft while stably holding the outer first shaft, the inner body translates and / or rotates relative to the outer body. Similarly, when the user translates and / or rotates the first shaft while maintaining the position of the second shaft, the outer body translates and / or rotates relative to the inner body. Depending on the configuration of the first shaft and the second shaft, the relative translation may be a linear motion, a rotation about the longitudinal axis, or a combination of the two. The translation of the bodies offsets the inner body cell and the outer body cell in which the blood clot protrudes, thereby compressing the blood clot between the opposing edges of the respective cells.

[0023] A method for treating a patient having a blood clot occluding a blood vessel using the disclosed device may include delivering a blood clot retrieval device across the blood clot. The device may have a folded delivery configuration and an expanded deployment configuration, an elongate shaft for controlling the device, and an expandable element distal to the elongate shaft. The folded delivery configuration allows the blood clot retrieval device to be delivered through a catheter having a relatively small bore, such as a microcatheter, before expanding at the target site when the catheter is withdrawn.

[0024] The expandable element may have an inner body including a plurality of cells and an outer body including a plurality of cells and expandable to a radial size larger than the inner body in the deployed state. The inner body and the outer body may be configured to translate relative to each other about the longitudinal axis between the deployment configuration and the blood clot clamping configuration.

[0025] The elongated shaft may have a first shaft connected to the outer body and a second shaft connected to the inner body. The translation of the outer body and the inner body can be achieved, for example, by configuring the first shaft and the second shaft to be selectively movable relative to each other. The method may then include the step of using the second shaft to selectively impart motion to the outer body relative to the inner body or to the inner body relative to the outer body by means of the first shaft. This motion can be linear, curved, rotational, a combination of these, or another suitable profile.

[0026] Another step may include restricting the range of translation of the first shaft and the second shaft relative to each other. The limiting function can assist in preventing the user from moving the inner body and the outer body beyond the design limits, and an increase in the offset of the cells of the body can result in weakening the gripping force on the blood clot or shearing the blood clot. The limitation can be achieved by using a slot, a sleeve, a cam / follower, or other suitable device as a physical stopper to prevent further translation of the shaft.

[0027] A further step may include deploying the blood clot retrieval device into an expanded deployment configuration such that the cells of the inner body are aligned and exposed with the cells of the outer body. When expanded, both the inner body and the outer body exert an outward radial force on the blood clot, sandwich the blood clot against the vessel wall, and bias at least a portion of the blood clot radially inwardly through the openings in the cells of the inner body and the outer body. When each portion of the blood clot protrudes through the cell opening, the user can translate one of the inner body or the outer body relative to the other to transition the device from the expanded deployment configuration to sandwich the blood clot between the cell struts of the inner body and the struts of the cells of the outer body. The sandwiched blood clot is compressed and firmly held between the cells, and the blood clot retrieval device can be withdrawn from the blood vessel while the gripping force is maintained by maintaining the relative translation between the inner body and the outer body. The blood clot retrieval device and the sandwiched blood clot can then be retrieved from the patient, either independently or by pulling the device and the blood clot into an outer catheter or an intermediate catheter.

[0028] In many cases, after retrieving some or all of the occlusive blood clot, a contrast agent can be injected through the outer catheter so that a more complete assessment of vessel patency can be made. If an occlusion remains within the blood vessel, additional passageways can be formed by the blood clot retrieval device. Then, once it is confirmed that the target blood vessel has been successfully reopened, all remaining devices can be removed from the patient. The devices of the present disclosure provide a means for minimizing the number of catheter advancements required to treat a patient, thereby reducing the potential for blood vessel injury and the risk of associated vessel dissection, even when multiple passageways are required.

[0029] Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art upon consideration of the following detailed description in conjunction with the accompanying figures.

Brief Description of the Drawings

[0030] These and further aspects of the present invention will be further discussed with reference to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate functionally similar or identical elements. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. The figures depict one or more implementations of devices of the present invention, by way of example only, and not by way of limitation.

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[0031] The goal of the disclosed design is to create a clot retrieval device capable of more effectively and efficiently removing clots of a wide range of compositions within the vasculature while maintaining a high level of deliverability and flexibility during the procedure. This design can have an outer expandable body with an inner expandable body extending therethrough. The disclosed devices share a common theme of a double-layered structure, with the outer and inner bodies having large cell openings that allow portions of the clot to move into the openings via radial force. One of the outer or inner members is then translated relative to the other body, causing the previously aligned cell openings to close, clamping the portion or portions of the clot internally. These clamping designs increase the retention security of the clot retrieval device.

[0032] Both the inner and outer expandable members are desirably made from a material that can automatically recover its shape when released from a significantly strained delivery configuration. The material can come in many forms, such as wire, strip, sheet, or tube. A suitable manufacturing process can be laser cutting a nitinol tube, then heat treating and electropolishing the resulting structure to create a framework of struts and connecting elements. As described, a range of designs is contemplated for each of these elements, and it is intended that any of these elements can be used with any other element, although to avoid repetition, these elements are not shown in all possible combinations.

[0033] Here, specific examples of the present invention will be described in detail with reference to the drawings. Although these descriptions are often related to mechanical thrombectomy treatment, the present design can be similarly adapted to other procedures and other body passages.

[0034] Regardless of whether it is a coronary vessel, a pulmonary vessel, or a cerebral vessel, accessing various vessels within the vasculature to reach a blood clot involves well-known procedural steps and the use of many conventional commercially available accessory products. These products, such as angiographic materials, rotary hemostatic valves, delivery access catheters, and guidewires, are widely used in examination institutions and medical procedures. If these or similar products are used in conjunction with the disclosure of the present invention in the following description, their functions and exact configurations will not be described in detail.

[0035] Referring to FIG. 1, the blood clot retrieval device 100 may have an elongated shaft 6 and an expandable member 101 configured at the distal end of the elongated shaft. The expandable member 101 may have an inner body 110 and an outer body 210 that are expandable from a delivery configuration that is folded or constrained at the target site of vascular occlusion to an expanded deployment configuration. The delivery method may be, for example, through a microcatheter or through some other outer catheter, depending on the access requirements of the target location. The occlusion may be a thrombus (blood clot), atherosclerotic plaque, or any other occlusion that impedes blood flow within the vessel.

[0036] The outer body 210 may have a generally tubular shape extending from the connection portion at the proximal end 212 to the elongated shaft 6 and the distal end 213. The inner body 110 may also have a substantially tubular profile and may extend through the interior of the outer body 210. The inner body 110 may also be connected to the elongated shaft, but need not share a connection with the outer body 210. In other words, both bodies may be fixedly connected to the shaft, but need not necessarily share the same connection point at the proximal end 112 of the inner body. Then, depending on the particular shaft design, the inner body 110 and the outer body 210 may be selectively translatable relative to each other such that a portion of a blood clot or occlusion can be clamped and captured. This blood clot clamping configuration may be activated, for example, by rotation or linear translation of the inner body 110 relative to the outer body 210. This clamping facilitates removal of the blood clot, particularly in the case of a fibrin-rich blood clot, by increasing the gripping force of the device on the blood clot. This clamping may also reduce the expulsion force by stretching the blood clot and thereby pulling the blood clot away from the vessel wall during the expulsion process. Retention of the blood clot therebetween may be improved during retrieval into the microcatheter or outer catheter by controlling the proximal end of the blood clot and preventing its proximal end from snagging on a collateral vessel.

[0037] The distal end 213 of the outer body 210 and the distal end 113 of the inner body 110 may form an annular profile about the axis 111 of the expandable member 101 to define the inner lumen 119 of the device 100. The distal end 213 of the outer body 210 may be planar with the distal end 113 of the inner member 110, or may form another shape with a mostly non-traumatic profile to avoid vessel trauma when deployed and expanded at the target site. In some examples, a flared or contoured end as shown may prove advantageous in situations where angled struts may provide a greater radial force or where the distal apex 236 on the final ring of the cell may be used to assist in expelling stubborn blood clots. The distal apex 236 may be offset from the longitudinal axis 111 of the device 100 and may be proximate to the cylindrical surface defined by the outer body 210 when expanded.

[0038] The inner body 110 and the outer body 210 are preferably made of a superelastic or pseudoelastic material, such as nitinol or another such alloy having a high recoverable strain. Some of all the elongate shafts 6 may be tapered wires, or may be made of stainless steel, MP35N, nitinol, or other materials having a moderately high modulus of elasticity and tensile strength. The advantage of using a self-expanding body with these materials is that, due to the volume characteristics and rigidity of the target blood clot, the device 100 can initially expand only to a fraction of its freely expanded diameter when the device is deployed over the entire blood clot due to the resistance. Thereby, the outer body 210 is given the ability to further expand to a larger diameter even while being retracted, such that the outer body can maintain contact with the vessel wall when being gradually retracted to a larger and more proximal vessel.

[0039] The shaft 6 and the device 100 may also have an indication band or marker for indicating to the user that the distal end of the device is approaching the end of the microcatheter during insertion, or for marking the distal portion of the device during the procedure. These indication bands can be formed by coating an area of the shaft for coating, or printing, removing, or masking a radiopaque element visible under fluoroscopy so as to be visually distinguishable from the rest of the shaft.

[0040] The shaft 6 may be coated with a material or may have a polymeric jacket to reduce friction and thrombus formation. The coating or jacket may consist of a polymer, a low-friction lubricant such as silicone, or a hydrophilic / hydrophobic coating. This coating may also be applied to part or all of the outer body 210 and the inner body 110.

[0041] The double-layer multi-diameter device 100, as shown in various figures throughout the present disclosure, has several advantages. Both the outer body 210 and the inner body 110 are self-expanding stent-like structures, and the outer diameter of the inner body is approximately equal to the inner diameter of the outer body in the free-expanded state. Thus, when the outer body 210 is constrained within a blood vessel and / or a blood clot, the inner body 110 is itself constrained by the outer body. In one example, the outer diameter of the inner body 110 is within 20% of the inner diameter of the outer body 210 in the free-expanded state. In a more preferred example, the outer diameter of the inner body 110 is within 10% of the inner diameter of the outer body 210 in the free-expanded state. In the most preferred example, the outer diameter of the inner body 110 is equal to or slightly larger than the inner diameter of the outer body 210 in the free-expanded state if the device must be disassembled so that the inner body is not constrained within the outer body.

[0042] This radial dimension of the outer body 210 can enable the outer body to maintain contact with the vessel wall and be juxtaposed with the vessel wall as the device is retracted proximally into a blood vessel with a gradually increasing diameter, and also prevent the blood clot from moving distally. The juxtaposition with the vessel wall can also reduce the axial force required to initially expel the blood clot from the blood vessel.

[0043] A side view of a composite device 100 having a double inner expandable body 110 and an outer expandable body 210 similar to that of FIG. 1 is shown in FIG. 2. Both the inner body 110 and the outer body 210 may be monolithic structures, and the outer body is configured to substantially surround the inner body therein. The cells 114 of the inner body 110 and the cells 214 of the outer body 210 function as inlets for blood clots and also enable the device to 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 when the device is retracted (i.e., substantially parallel to the longitudinal axis 111). This means that any outward radial force applied to the vasculature by the outer body 210 can be minimized. By configuring the outer body 210 to facilitate the blood clot crossing to the inner lumen 119, the device can more effectively disengage the blood clot from the blood vessel wall. The inner body 110 and the outer body 210 may also have open distal ends 113, 213 or may be configured with debris blocking elements (not shown) to prevent the distal movement of blood clot fragments or other debris during the procedure.

[0044] The cells 114 of the inner body 110 and the cells 214 of the outer body 210 can have various shapes. FIG. 2 shows cells having a mostly hexagonal shape, although some other polygon may be used. These cells of the inner and outer bodies can allow the device to accommodate small differences in length by stretching without applying significant tensile or compressive forces to the joints. The differences in length can occur, for example, when the device is expanded, folded, or deployed within a small blood vessel. The hexagonal configuration of the struts of the inner body cells 114 and the outer body cells 214 allows the cells to fully extend and contract such that the lengths of the inner body 110 and the outer body 210 can be substantially the same when loaded within a microcatheter and when freely expanded at the target site. However, the cell shape can have sufficient structural rigidity such that the device 100 can be advanced or retracted without overly extending and shortening the inner body 110 and the outer body 210.

[0045] The shapes of cells 114 and 214 can be selected so as not to significantly impair the ability to receive a blood clot that at least partially penetrates inside device 100. In many cases, the cells can be closed together with the vertices of inner body cell 114 joined to adjacent cells at inner junction 144 and outer body cell 214 joined at outer junction 244, as shown. In another example, there can be a combination of open cells and closed cells, where the open cells have a ring of struts that are discontinuous from a ring of axially adjacent cells.

[0046] Inner body 110 and outer body 210 can be configured to generate different radial forces upon expansion into a deployed configuration. This can be achieved by a plurality of ways such as different geometric shapes, materials, etc., or by heat setting with different residual strains. In one example, outer body 210 can have a radial force that is limited so as not to cause vascular trauma, and inner body 110 can have a higher radial force, such that a strong opening force can form a lumen through at least a portion of the blood clot to restore blood flow during deployment. A certain amount of restricted blood flow through the lumen can ensure that the pressure applied to the blood vessel immediately after blood flow recovery is lower than normal, thereby reducing the risk of bleeding in the vascular bed. Thereafter, complete perfusion can be restored by removing the device and the captured blood clot. In other examples, the radial force of outer body 210 and the radial force of inner body 110 may be substantially equal, or the outer body may have a greater radial force to pinch and twist each part of the blood clot as the bodies are translated.

[0047] The device shaft 6 may be subdivided into two separate shafts, a first shaft 8 and a second shaft 7, which are coincident with each other and the longitudinal axis 111 of the device 100. Proximally, the device outer body 210 may have support arms 222 that join the first shaft 8 at a proximal junction and radiate outward in a conical fashion to the outer diameter of the body. The support arms 222 may have a tapered profile, as shown, to ensure a gradual stiffness transition from the first shaft 8 to the full tubular profile of the clot-engaging outer body 210. The support arms 222 may vary in number and placement at distinct locations around the longitudinal axis 111 of the device 100, such that small or large circumferential gaps exist between adjacent arms.

[0048] The inner body 110 can have inner support arms 122 that join the second shaft 7. Similar to the support arms 222 of the outer body 210, the inner support arms 122 can taper from the tubular portion of the inner body to the shaft 7 and can be parallel to the longitudinal axis 111, at an angle to the longitudinal axis 111, or twisted about the longitudinal axis 111. If formed with a twist about an axis, the support arms 122 can induce a twist on the inner body 110 of the device relative to the outer body 210 as they are retracted into the outer catheter. Alternatively, a suitable outer catheter can be advanced over the device so that it impinges on the support arms 122. This rotational twist can be another way to close previously aligned cells 114, 214 of the inner and outer bodies to grasp a clot in a clot-clamping configuration. Similarly, even if clamping has already been achieved between the cells of the inner body 110 and the cells of the outer body 210 by relative translation, the device can still be retracted into the outer catheter if desired to collide the inner support arms 122 and outer support arms 222 to further clamp the proximal portion of the clot, while the cells of the expandable body can maintain a secure grip on the clot without interference.

[0049] The support arm 122 may also have a bend or crown that biases movement in a direction away from or not at least the same as the blood clot clamping cell, such that the support arm does not shear each part of the blood clot even when the proximal portion of the device is partially constrained by the outer catheter. The bend or crown can also assist in providing a strong gripping force against the blood clot for the initial clinical step of disengaging the blood clot from the blood vessel, allowing the outer body 210 to be configured with a low radial force. The connection of the inner body cell 114 and the outer body cell 214 to the support arms 122, 222 can be substantially aligned to align the neutral axes of the inner and outer bodies during bending within the vascular structure.

[0050] The most distal portions of the inner body 110 and the outer body 210 may be open as shown, or alternatively, may have a tapered end that tapers radially with a substantially conical profile relative to the distal end 213. The tapering and convergence of the struts at the end can reduce the pore size of the cell openings between the struts to form a debris capture zone. In a further example, the distal end 213 of the outer body 210 may include a distal apex 236 that is raised or flared so as to be atraumatic to the blood vessel being used. The struts forming the raised or flare may not be parallel to the struts of the adjacent portion of the outer body 210. The distal end 213 may also be provided with radiopaque properties for marking the distal end of the device 100 during treatment.

[0051] Another example of a blood clot retrieval device 100 having a bilayer structure with an inner body 110 and an outer body 210 disposed about a longitudinal axis 111 is shown in FIG. 3. In this example, the cells 114 of the inner body 110 and the cells 214 of the outer body 210 may have an irregular shape, such that the struts have bends or extend in a curvilinear fashion that may not be an axial mirror image from one set or ring of cells to the next. In the figure, the rings of cells forming the device may be bounded by sinusoidal edges where they meet at the inner body junction 144 and the outer body junction 244. The sinusoidal edges mean that the magnitude (or amplitude) of the peaks and valleys of the radial force can vary along the length of the device 100. This irregular cell shape allows the device to provide acute angles and higher radial pressure (radial force per surface area) in various regions to assist in embedding and gripping the blood clot.

[0052] When each part of the blood clot contacts the device, the small surface area and radial force may allow a part of the blood clot to protrude through the inner body cells 114 and the outer body cells 214. For a given level of radial force, the radial pressure of the device can be increased by reducing the number of struts that make up the cell or strut width.

[0053] The elongate shaft 6 can be configured to allow the inner body 110 and the outer body 210 to be independently manipulated and / or translated. Translation can be, for example, linear translation along an axis, rotation of one body relative to the other, or some combination thereof. A user can transition the device 100 in a number of ways, from aligning the cells 114 of the inner body 110 with the cells 214 of the outer body 210 when in the expanded, deployed configuration, to being offset in the clot-clamping configuration. Examples of this change in orientation are shown in FIGS. 5 and 6, where FIG. 5 shows the cells initially aligned when the device is initially deployed within the target clot. As shown in FIG. 4, the device shaft 6 can be subdivided into two separate shafts that are coincident with each other and with the longitudinal axis 111 of the device 100. The shaft structure can be of a sufficiently rigid material or combination of materials to allow force transmission from the user at the proximal end external to the patient. The first shaft 8 may be connected to the proximal end 212 of the outer body 212, and the second shaft 7 may be connected to the proximal end 112 of the inner body 110. The first shaft 8 may have a tubular elongate body 320 such that the second shaft 7 may reside within the lumen 322 of the first shaft.

[0054] The clot clamping configuration of device 100 can be achieved by translation of inner body 110 relative to outer body 210, or alternatively, translation of outer body 210 relative to inner body 110. In the example shown in FIG. 4 , index pin 312 can extend radially from second shaft 7 and reside within slot 324 in elongate body 320 of first shaft 8. When the axis of slot 324 is aligned parallel to longitudinal axis 111 as shown, a user can push or pull one shaft relative to the other to induce linear translation within the body cell.

[0055] When the cells are aligned as shown in FIG. 5, for example, by stably holding the first shaft 8 while pushing the second shaft 7, linear translation along the axis 111 of the inner body 110 is caused, and the cells 114 of the inner body 110 are closed against the cells 214 of the outer body 210 together with the protruding blood clot. The translation results in a new orientation of the cells 114, 214 as seen in FIG. 6. The angled joints 144 formed by the struts 116 of the inner body 110 can function as a net during translation, gripping the protruding portion of the blood clot and sandwiching the protruding portion against the respective joints 244 formed by the struts 216 of the outer body 210. In an alternative example, by stably holding the second shaft 7 while pushing or pulling the first shaft 8, linear translation along the axis 111 of the outer body 210 is caused, the cells 214 of the outer body 210 are closed against the cells 114 of the inner body 110, and the protruding blood clot is sandwiched. It is also conceivable that both the first shaft 8 and the second shaft 7 are translated simultaneously in opposite directions to achieve the same function. The end portion of the slot 324 can limit the applied acceptable translation to prevent accidental shear or loss of gripping force on the captured blood clot. Partially re-sheathing the device 100 during retrieval with a microcatheter, intermediate catheter, or other external sheath can add additional clamping force on the protruding blood clot (in addition to the protruding blood clot between the cells of the inner body and the cells of the outer body) between the tip of the catheter or sheath and the proximal struts of the inner body 110 and the outer body 210.

[0056] Another example of using an index pin as a means for controlling the transition of device 100 into the clot-clamping configuration is shown in FIG. 7. As with the previous example, second shaft 7 can reside within lumen 322 of tubular first shaft 8 so that the shafts are translatable and rotatable relative to one another. Index pin 312 can extend radially from second shaft 7 and reside within slot 324 cut into elongated body 320 of first shaft 8 such that the axis of the slot forms angle 326 with respect to longitudinal axis 111. When the axis of slot 324 is aligned parallel to longitudinal axis 111 (see FIG. 4), a user can push or pull one shaft relative to the other to induce linear translation within the body cell. However, the angular slots as shown mean that a push / pull force on second shaft 7 relative to first shaft 8 results in both linear translation and angular rotation (see arrows in FIG. 7 ) of inner body member 110 relative to outer body member 210. A single push / pull force from the user is required for this actuation, as slot 324 guides the required movement of index pin 312. This movement transitions from the deployed state of inner body cell 114 and outer body cell 214 as shown in FIG. 8 to the clot-clamping configuration of the cells offset from axes 111 and 150 as shown in FIG. 9 .

[0057] In this method of activating the clot clamping configuration of device 100, it can be seen that the more acute the angle 326 of slot 324 in first shaft 8 relative to longitudinal axis 111, the greater the relative component of linear translation between cells 114 of inner body 110 and cells 214 of outer body 210. Similarly, a more obtuse angle 326 will result in a greater relative component of rotation of the bodies about axis 111.

[0058] An inner body 110 and an outer body 210 of device 100 in an extended deployment configuration, and more extensive views of those inner and outer bodies after being operated into a blood clot clamping configuration, are shown in FIGS. 10 and 11, respectively. The outer body 210 can expand and contact the blood vessel wall when the microcatheter is retracted during deployment of the device. The juxtaposition with the wall provides stability to the device 100 and also minimizes torsional twisting in the deployment between the outer body 210 and the inner body 110 when the device is sheath-exited within the blood vessel. Thereby, by clamping the blood clot against the blood vessel wall, uniform deployment and expansion of the device 100 within the occlusion or blood clot 20 is facilitated. When deployed, the radial force due to the expansion of the body about axis 111 will urge the blood clot 20 through the openings in cells 114, 214.

[0059] The expansion of the inner body 110 and the outer body 210 can cause compression and / or displacement of the blood clot during expansion, depending on the level of the scaffold support provided by the struts. When the expandable body provides a high level of scaffold, the blood clot can be compressed. Alternatively, when the expandable body provides an escape route or opening, the expanding body will urge the blood clot towards the opening. The blood clot itself can have a lot of degrees of freedom and can move in various different directions. When the device is sufficiently long, many of the degrees of freedom of movement available to the blood clot are eliminated. Thereby, the blood clot can be retrieved without excessive compression. This is advantageous because compression of the blood clot can dehydrate the blood clot, but in turn increases the frictional properties and stiffness, thereby making it more difficult to disengage and remove the blood clot from the blood vessel. This compression can be avoided when the body expands outwardly towards the blood vessel wall and the blood clot easily moves inwardly through the cells or easily moves through the gap between the proximal portions of the inner body 110 and the outer body 210.

[0060] When the blood clot clamping structure is activated by utilizing the relative displacement and / or rotation (arrows in FIG. 11) between the inner body 110 and the outer body 210, the struts 116 forming the inner body cell 114 are no longer aligned with the struts 216 forming the outer body cell 214 as shown in FIG. 11. The blood clot 20 is collided and compressed between the struts forming the cells, enabling clamping that firmly grips the area of the blood clot for expulsion from the initial blood vessel and subsequent retrieval.

[0061] FIGS. 12 and 13 show the steps of a method for performing a thrombus removal procedure using such a device. The steps of this method can be implemented by either an exemplary device described herein or a suitable alternative known to those skilled in the art. The method may have some or all of the described steps, but in many cases, each step can be performed in an order different from that disclosed below.

[0062] Referring to the method 1200 outlined in FIG. 12, step 1210 may include delivering a blood clot retrieval device across a target blood clot. The blood clot retrieval device can be delivered through a microcatheter or other suitable delivery catheter and may have a folded configuration during delivery and an expanded deployment configuration when the delivery catheter is retracted. An elongate shaft can be used to operate the device by the user. The expandable element may be attached to the distal end of the elongate shaft and may have an outer body extending along the longitudinal axis with a substantially tubular lumen. The inner body may be disposed axially within the lumen of the outer body and may be radially expandable within a range smaller than the outer body so as to be fully accommodated. The inner body and the outer body may be capable of translating along the longitudinal axis relative to each other and / or about the longitudinal axis so that the device transitions from the deployment configuration to clamp and grip the blood clot in the blood clot clamping configuration.

[0063] In many cases, the inner body can expand only to a slightly smaller outer diameter than the outer body and may be configured to generate a radial force that may be greater than, less than, or equal to the radial force generated by the outer body, allowing the inner and outer bodies to be tailored to the size, location, and composition of the target clot to increase the chances of first-pass success of the device.

[0064] Both the inner and outer bodies can be made from struts that form multiple cells. The cells can be any variety of shapes and sizes. In step 1220, the bodies can be configured so that, when expanded and deployed, the openings in the cells of both bodies are largely aligned both axially and circumferentially. The cells can have a large central opening, which allows the device to appose with the vessel wall when expanded, while the limited scaffolding provided by the struts can compress and embed the target clot. Portions of the nearby clot can then easily pass inward simultaneously through the gaps in the inner and outer body cells.

[0065] The device may be configured such that the elongate shaft is formed from a first shaft connected to the proximal end of the outer body and a second shaft connected to the proximal end of the inner body, as in step 1230. The second shaft may be coincident with the first shaft, for example, so that it may be selectively used to linearly translate or rotate the inner body independently of the outer body. Similarly, the first shaft may be used to linearly translate or rotate the outer body independently of the inner body.

[0066] Alternatively, some other mechanism can be utilized in this process to clamp the clot. For example, the proximal support arms of the inner or outer body can be formed at an angle to the longitudinal axis so that when the microcatheter or outer catheter is advanced into the support arms beyond the proximal end of the expandable body, a twist can be imparted onto one of the bodies relative to the other.

[0067] The device can be delivered to the occluded blood vessel through a microcatheter in a collapsed delivery configuration. In the case of intracranial occlusions, various access routes are possible, including a direct stick to the carotid artery, a brachial approach, or femoral access. Once access to the arterial system is gained using conventional and well-understood techniques, a guide catheter or long sheath is typically placed as close as practical to the occlusive clot. For example, in the case of a middle cerebral artery occlusion, a guide catheter can be placed in the internal carotid artery proximal to the carotid siphon. The microcatheter can then be advanced throughout the clot, with or without the aid of a guidewire. Once the microcatheter tip has crossed the clot and advanced distally of the clot, the guidewire, if used, can be removed, and the clot retrieval device is advanced through the microcatheter until it reaches its distal end. The microcatheter can then be retracted, allowing the clot retrieval device to expand into and to either side of the occlusive clot.

[0068] Step 1240 includes deploying the clot retrieval device to an expanded, deployed configuration. Radial forces applied by the inner and outer bodies of the device can urge at least a portion of the clot radially inward through the aligned cell openings. Because the majority of the clot does not need to fully enter the inner lumen of the device, the applied radial pressure does not need to be very high, so clot compaction can be controlled and minimized. Minimizing clot compaction reduces the frictional forces that must be overcome to expel and retract the clot.

[0069] Continuing with reference to FIG. 13 , method 1300 may include step 1310 of translating the inner body relative to the outer body or the outer body relative to the inner body to compress and clamp at least a portion of the clot between the struts of the inner body cells and the struts of the outer body cells. Translation may be linear, rotational, or a combination of the two. Achieving translational motion may be achieved through a system having an inner shaft and an outer shaft, as previously described. Alternatively, advancing the outer catheter over a helically arranged proximal portion of the device may apply a tangential force to the helical portion of the device, causing it to twist and / or rotate relative to the other portions. Regardless, the relative translation serves to compress and clamp the clot between the struts of the inner body cells and the struts of the outer body cells. This step may be performed with the assistance of suction through the outer catheter and / or guide catheter to help maintain a firm grip on the clot and avoid loss of debris. If necessary during the procedure, reversing the process of step 1310 may transition the device from the clot clamping configuration back to the expanded deployed configuration.

[0070] When the microcatheter or other outer catheter is advanced to increase the grip on the clot, the user can feel the grip as resistance and stop the advancement of the catheter, or alternatively, advance it a fixed distance over the entire proximal end of the expandable body. A relatively low level of scaffolding in the expandable body allows the relative tension between the device and the catheter to be maintained so that the grip does not decrease during clot retraction.

[0071] In step 1320, the inner or outer shaft may be provided with features such as a pin in a slot or a cam and follower arrangement to limit the overall relative motion between the inner and outer bodies when transitioning to and from the clot clamping configuration. Limiting translation ensures that the clot is clamped but not sheared or fragmented.

[0072] In procedure 1330, a blood clot retrieval device having a clamped blood clot can be withdrawn from a blood vessel while maintaining the clamping between the cells of the inner body and the cells of the outer body. Along with suction, this engagement maintains a firm clamping grip on the blood clot as it is withdrawn through the bend and continuously larger blood vessel diameters.

[0073] In procedure 1340, the blood clot retrieval device and the clamped blood clot can be removed from the patient. Optionally, the device can be rinsed with saline and gently cleaned before being reloaded into the microcatheter. It can then be reintroduced into the vasculature to be redeployed to a further area of occlusive blood clot or when a further passage for complete recanalization is required.

[0074] The present invention is not necessarily limited to the described examples, which may vary in composition and detail. The terms "distal" and "proximal" are used throughout the foregoing description and are meant to refer to the position and direction with respect 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. Further, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" include plural referents.

[0075] 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 enables a component part or a 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%.

[0076] When describing the exemplary embodiments, technical terms are used for clarity. Each term is intended to have its broadest meaning as understood by those skilled in the art and is intended to include all technical equivalents that act in a similar manner to achieve a similar purpose without departing from the scope and spirit of the present disclosure. It should also be understood that the 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. Similarly, some steps of the method can be performed in an order different from that described herein without departing from the scope of the disclosed technology. For the sake of clarity and brevity, not all possible combinations are listed, and such variations are often obvious to those skilled in the art and are intended to be within the scope of the following claims.

[0077] 〔Embodiment〕 (1) A device for removing a blood clot from a blood vessel, having a constrained delivery configuration and an expanded deployment configuration, a first shaft, a second shaft, and a framework of struts forming an expandable member extending distally from the first shaft and the second shaft, wherein the expandable member has an inner tubular lumen and a longitudinal axis extending therethrough, an inner body connected to the second shaft, the inner body comprising a plurality of cells expandable about the longitudinal axis in the deployment configuration, an outer body connected to the first shaft, the outer body comprising a plurality of cells expandable more than the inner body in the deployment configuration, and the inner body and the outer body are translatable relative to each other about the longitudinal axis between the deployment configuration and the blood clot clamping configuration, wherein the cells of the inner body and the cells of the outer body are configured to clamp a blood clot located within the cells when in the blood clot clamping configuration. (2) A device as described in embodiment 1, wherein the cells of the inner body are approximately equal in size to the cells of the outer body. (3) The device of embodiment 1, wherein in the expanded, deployed configuration, the cells of the inner body are aligned with the cells of the outer body. (4) A device as described in embodiment 1, wherein the cells of the inner body and the outer body are configured to fit into the blood clot in the expanded, deployed configuration. (5) The device of embodiment 1, wherein the clot clamping configuration is achieved by translating the inner body relative to the outer body until at least a portion of the clot is compressed between the cells of the inner body and the cells of the outer body.

[0078] (6) A device as described in embodiment 1, wherein the first shaft comprises an elongate body, an inner lumen, and a slot adjacent its distal end. (7) The device of embodiment 6, wherein the second shaft is disposed within the lumen of the first shaft and includes an index pin extending radially from an outer surface of the second shaft, the index pin configured to engage with the slot of the first shaft. (8) The device of embodiment 7, wherein the axis of the slot forms an angle with the longitudinal axis such that linear translation of the second shaft relative to the first shaft causes rotation of the index pin within the slot. (9) A device as described in embodiment 1, wherein regions of the inner body and the outer body are configured to exert an outward radial force on the clot to urge the clot toward the inner tubular lumen. (10) A device for treating an occlusion in a body vessel, comprising: a tubular inner lumen configured about a longitudinal axis; an inner body having a constrained delivery configuration, an expanded deployed configuration, and a plurality of struts forming an inner clot scaffolding section; An outer body disposed around the inner body, the outer body comprising a constrained delivery configuration, an expanded deployment configuration, and a plurality of struts forming an outer blood clot scaffold assembly section. An elongated shaft extending proximally with respect to the inner body and the outer body. The inner body and the outer body are translatable relative to each other about the longitudinal axis between the deployment configuration and the blood clot clamping configuration. At least a portion of the blood clot is compressed between the struts of the inner body and the struts of the outer body when the inner body is in the blood clot clamping configuration. A device.

[0079] (11) The struts of the scaffold assembly section of the inner body and the outer body form a ring of cells. The device according to embodiment 10. (12) The cells of the inner body are substantially equal in size to the cells of the outer body. The device according to embodiment 11. (13) In the expanded deployment configuration, the cells of the inner body are aligned with the cells of the outer body. The device according to embodiment 11. (14) The scaffold assembly sections of the inner body and the outer body are configured to exert an outward radial force on the blood clot to bias the blood clot radially inwardly toward the inner tubular lumen. The device according to embodiment 10. (15) The shaft includes a first shaft connected to the outer body and a second shaft connected to the inner body. The device according to embodiment 10.

[0080] (16) The first shaft and the second shaft are configured to translate the inner body relative to the outer body. The device according to embodiment 15. (17) The struts of the scaffold assembly section of the inner body (110) and the outer body (210) are configured to engage the blood clot in the expanded deployment configuration. The device according to embodiment 10. (18) A method for treating a patient having a blood clot occluding a blood vessel, comprising: delivering a blood clot retrieval device across the blood clot, the blood clot retrieval device comprising: a folded delivery configuration, an expanded deployment configuration, an elongate shaft, and an expandable element distal to the elongate shaft, the expandable element comprising: an inner body having a plurality of cells; an outer body extending longitudinally around the inner body along a longitudinal axis and having a plurality of cells, the outer body being expandable larger than the inner body in the deployment configuration; delivering, wherein the inner body and the outer body are configured to translate relative to each other about the longitudinal axis between the deployment configuration and a blood clot clamping configuration; deploying the blood clot retrieval device into the expanded deployment configuration such that the cells of the inner body and the cells of the outer body are aligned; applying a radial force by the device such that at least a portion of the blood clot is biased radially inwardly through the openings of the cells of the inner body and the outer body; translating the inner body relative to the outer body to compress and clamp at least a portion of the blood clot between the struts of the cells of the inner body and the struts of the cells of the outer body; withdrawing the blood clot retrieval device from the blood vessel while maintaining at least a portion of the relative translation between the inner body and the outer body to maintain the gripping force on the blood clot; removing the blood clot retrieval device and the clamped blood clot from the patient. (19) The elongate shaft includes a first shaft connected to the outer body and a second shaft connected to the inner body, the first shaft and the second shaft being configured to be selectively movable relative to each other. 19. The method of embodiment 18, wherein the first shaft selectively imparts movement to the outer body relative to the inner body, and the second shaft selectively imparts movement to the inner body relative to the outer body. (20) The method of embodiment 19, wherein the first shaft is configured to limit the range of translation of the second shaft.

Claims

1. A device for removing blood clots from a blood vessel, having a constrained delivery configuration and an expanded deployment configuration, comprising: a first shaft, a second shaft, and a framework of struts forming an expandable member extending distally from said first shaft and said second shaft, said expandable member having an inner tubular lumen and a longitudinal axis extending therethrough, an inner body connected to said second shaft, said inner body comprising a plurality of cells expandable about said longitudinal axis in said deployment configuration, an outer body connected to said first shaft, said outer body comprising a plurality of cells expandable larger than said inner body in said deployment configuration, said inner body and said outer body being translatable relative to each other about said longitudinal axis between said deployment configuration and a blood clot clamping configuration, said plurality of cells of said inner body and said plurality of cells of said outer body being configured to clamp a blood clot located within said plurality of cells when in said blood clot clamping configuration.

2. The device according to claim 1, wherein said plurality of cells of said inner body are substantially equal in size to said plurality of cells of said outer body.

3. The device according to claim 1, wherein in said expanded deployment configuration, said plurality of cells of said inner body are aligned with said plurality of cells of said outer body.

4. The device according to claim 1, wherein said plurality of cells of said inner body and said plurality of cells of said outer body are configured to engage with the blood clot in said expanded deployment configuration.

5. The device according to claim 1, wherein said blood clot clamping configuration is achieved by translating said inner body relative to said outer body until at least a portion of said blood clot is compressed between said plurality of cells of said inner body and said plurality of cells of said outer body.

6. The device according to claim 1, wherein said first shaft comprises an elongate body, an internal lumen, and a slot proximate its distal end.

7. The device according to claim 6, wherein said second shaft is disposed within said lumen of said first shaft and comprises an index pin extending radially from an outer surface of said second shaft, said index pin being configured to engage said slot of said first shaft.

8. The axis of the slot forms an angle with the longitudinal axis such that linear translation of the second shaft relative to the first shaft causes rotation of the index pin within the slot, the device of claim 7.

9. The regions of the inner body and the outer body are configured to exert an outward radial force on the blood clot to bias the blood clot toward the inner tubular lumen, the device of claim 1.

10. A device for treating an occlusion within a body vessel, An inner tubular lumen configured about a longitudinal axis, An inner body comprising a constrained delivery configuration, an expanded deployment configuration, and a plurality of struts forming an inner blood clot scaffold section, An outer body disposed about the inner body, the outer body comprising a constrained delivery configuration, an expanded deployment configuration, and a plurality of struts forming an outer blood clot scaffold section, An elongate shaft extending proximally with respect to the inner body and the outer body, The inner body and the outer body are translatable relative to each other about the longitudinal axis between the deployment configuration and the blood clot clamping configuration, At least a portion of the blood clot is compressed between the plurality of struts of the inner body and the plurality of struts of the outer body when the inner body is in the blood clot clamping configuration, The elongate shaft includes a first shaft connected to the outer body and a second shaft connected to the inner body, a device.

11. The plurality of struts of the inner blood clot scaffold section of the inner body and the plurality of struts of the outer blood clot scaffold section of the outer body form a ring of cells, the device of claim 10.

12. The cells of the inner body are sized to be substantially equal to the cells of the outer body, the device of claim 11.

13. In the expanded deployment configuration, the cells of the inner body are aligned with the cells of the outer body, the device of claim 11.

14. The inner blood clot scaffold section of the inner body and the outer blood clot scaffold section of the outer body are configured to exert an outward radial force on the blood clot to bias the blood clot radially inwardly toward the inner tubular lumen, the device of claim 10.

15. The device according to claim 10, wherein the first shaft and the second shaft are configured to translate the inner body relative to the outer body. **Claim 16** The device according to claim 10, wherein the plurality of struts of the inner blood clot scaffold assembly section of the inner body and the plurality of struts of the outer blood clot scaffold assembly section of the outer body are configured to engage the blood clot in the expanded deployment configuration.

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