Vascular obstruction object retrieval device with sliding cage clamping mechanism

Abstract

To provide a clot retrieval device.SOLUTION: The disclosed technology includes a clot retrieval device configured to retrieve a clot from a blood vessel and having a constrained delivery configuration and a clot engaging configuration. The device includes a first expandable framework having a first plurality of struts that form a first body and a second expandable framework having a second plurality of struts that form a second body, upon the clot retrieval device transitioning from the constrained delivery configuration to the clot engaging configuration. In the clot engaging configuration, the first body can be configured to move from a first position to a second position in relation to the second body. Upon moving from the first position to the second position, the clot retrieval device can pinch the clot between the first body and the second body.SELECTED DRAWING: Figure 1A

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 in mechanical clot removal for endovascular interventions, particularly when patients suffer from conditions such as acute ischemic stroke (AIS), myocardial infarction (MI), and pulmonary embolism (PE). Acute obstructions can include clots, misplaced or dislodged devices, large emboli, etc. 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 into emboli without being released, locally blocking a blood vessel; this mechanism is common in the formation of coronary artery blockages.

[0003] There are significant challenges associated with designing a clot retrieval device that can provide a high level of performance. First, there are many access challenges that make delivering the device 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.

[0004] The problem of tortuosity is even more severe in arteries approaching the brain. For example, it is not uncommon for a device to have to navigate several centimeters of vessel through sections of vessel with 180°, 90°, and 360° bends at the distal end of the internal carotid artery. 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 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 guide catheters that are as low-profile and flexible as possible.

[0005] Second, the vasculature in the area where a clot may be lodged is often fragile and delicate. For example, neurovascular vessels may be more fragile than similarly sized vessels in other parts of the body and may reside in soft tissue beds. Excessive tensile force applied to these vessels can result in perforation and bleeding. Pulmonary vessels may be larger than those in the cerebral vasculature, but they are also inherently more delicate, especially the more distal vessels.

[0006] Furthermore, clots can have a range of morphologies and consistencies. For example, clots can be difficult to grasp, and improper grasping can result in fragmentation that can lead to embolism. Long, string-like, softer clot material also tends to lodge at bifurcations or trifurcations, resulting in simultaneous occlusion of multiple vessels over significant lengths. More mature, organized clot material may be less compressible than softer, newer clots, and under the influence of blood pressure, it may distend flexible vessels within which it is lodged. Furthermore, clot properties can be significantly altered by the action of devices interacting with the clot. In particular, clot compression can cause dehydration of the clot, which can dramatically increase the clot's hardness and coefficient of friction.

[0007] Finally, conventional clot retrieval devices that use a clamping mechanism to capture the clot may require the delivery microcatheter to be forward after deployment of the clot retrieval device in order to effectively clamp the clot using the device. However, this may add an additional step in the procedure, which may make the procedure cumbersome and suboptimal. Due to the critical nature of such procedures, it may be important to capture the clot in a timely and effective manner.

[0008] To achieve a high level of success in removing the clot and restoring blood flow, a device must overcome the above challenges. Summary of the Invention [Means for solving the problem]

[0009] Clot retrieval devices are desirable for removing clots from cerebral arteries in patients with AIS, from native coronary or graft vessels in patients with MI, from pulmonary arteries in patients with PE, and from other peripheral arteries and veins where a clot has caused at least partial obstruction. The exemplary devices and methods presented herein may be suitable for at least some of such and / or similar procedures.

[0010] An exemplary clot retrieval device can have a constrained delivery configuration and a clot engagement configuration and can be configured to remove a clot from a blood vessel. The device can include a first expandable framework having a first plurality of struts forming a first body and a second expandable framework having a second plurality of struts forming a second body. In the clot engagement configuration, the first body can be configured to move from a first position to a second position relative to the second body.

[0011] The first body can have a first inner diameter and the second body can have a second inner diameter. The first inner diameter and the second inner diameter can be substantially equal.

[0012] When the first body is in the first position, the first plurality of struts and the second plurality of struts may be disengaged to form a plurality of clot-receiving spaces.

[0013] When the first body is in the second position, the first plurality of struts and the second plurality of struts can be engaged, and when the first body moves from the first position to the second position, the average cross-sectional area of ​​the multiple clot-receiving spaces decreases.

[0014] The first plurality of struts can include radially extending struts, and the second plurality of struts can include eyes, with the radially extending struts extending radially through the eyes. The eyelets and radially extending struts can be configured such that when the first body moves from the first position to the second position, the radially extending struts engage the eyelets to prevent movement of the first plurality of struts relative to the second plurality of struts beyond the second position. Each eyelet can be tapered.

[0015] The clot retrieval device can include a polymeric coating for engaging the first and second plurality of struts. The polymeric coating can be configured to not allow the first body to move from the first position to the second position.

[0016] At least one polymeric membrane may be affixed to the first plurality of struts and the second plurality of struts, the polymeric membrane being disposed between the first body and the second body.

[0017] When the first body is in the first position, the at least one polymeric membrane can be in a collapsed configuration, and when the first body is moved proximally to the second position, the at least one polymeric membrane can transition to an extended configuration.

[0018] The clot retrieval device can include a third expandable framework having a third framework of struts forming a third body, and the first body and the second body can at least partially surround the third body in the clot-engaging configuration.

[0019] The proximal end of the clot retrieval device can include a plurality of enlarged struts that form a collar.

[0020] The framework of the third strut may include at least one cut strut.

[0021] The third body can include a plurality of clot-receiving spaces. The plurality of clot-receiving spaces can be configured to engage a clot.

[0022] Another exemplary clot retrieval device can have a constrained delivery configuration and a clot engagement configuration and can be configured to remove a clot from a blood vessel. The device can include an inner expandable framework, an outer expandable framework, and a spring. The inner expandable framework can be secured to the pull wire and can include a first plurality of struts forming an inner body. The outer expandable framework can be secured to the pull wire and can include a second plurality of struts forming an outer body at least partially surrounding the inner body. The spring can be secured to a distal end of the pull wire and can have a compressed configuration and an extended configuration. In the clot engagement configuration, the inner body can be configured to move from a first position to a second position relative to the outer body, with the spring transitioning from the compressed configuration to the extended configuration.

[0023] The outer expandable framework can include a plurality of clot-receiving spaces configured to sandwich a clot between the inner body and the outer body when the inner body is moved from the first position to the second position.

[0024] An exemplary method of capturing a clot can include deploying a clot retrieval device adjacent to the clot, the clot retrieval device including a first expandable framework forming a first body and a second expandable framework forming a second body at least partially surrounding the first body. The method can further include moving the first body relative to the second body to sandwich at least a portion of the clot between the first body and the second body and capturing one or more fragments of the clot.

[0025] Moving the first body relative to the second body to pinch at least a portion of the clot between the first body and the second body can include applying tension to a pull wire, the pull wire being in mechanical communication with the first body.

[0026] The method may further include simultaneously retracting the first body and the second body.

[0027] The clot retrieval device can further include a third expandable framework having a third plurality of struts forming a third body. The first body and the second body can at least partially surround the third body. In such a configuration, the method can further include retracting the third body proximally to engage the first body and the third body. [Brief explanation of the drawings]

[0028] [Figure 1A] FIG. 1 is a side view of an exemplary clot retrieval device in a clot engaging configuration in accordance with the present disclosure. [Figure 1B] 1B is an additional side view of the clot retrieval device of FIG. 1A from a different perspective in accordance with the present disclosure. [Figure 1C] 1C is a cross-sectional view of the shaft of the clot retrieval device of FIGS. 1A and 1B in accordance with the present disclosure. FIG. [Figure 1D] FIG. 1C is an enlarged view of a pull wire joined to a first plurality of struts of the clot retrieval device of FIGS. 1A and 1B in accordance with the present disclosure. [Figure 1E]FIG. 1C is an enlarged view of the radially extending struts and eyelets of the clot retrieval device of FIGS. 1A and 1B in accordance with the present disclosure. [Figure 1F] 1A and 1B when transitioned to a clot clamping configuration, according to the present disclosure. FIG. [Figure 1G] FIG. 1C is an additional side view of a clot retrieval device in the clot clamping configuration shown in FIG. 1F according to the present disclosure. [Figure 2A] 12 is a side view of an additional exemplary clot retrieval device in a clot engaging configuration according to the present disclosure. [Figure 2B] 2B is a cross-sectional view of a proximal portion of the clot retrieval device of FIG. 2A in accordance with the present disclosure. [Figure 2C] 2B illustrates an example of a third body of the clot removal device of FIG. 2A in accordance with the present disclosure. [Figure 2D] 2B illustrates an example of a third body of the clot removal device of FIG. 2A in accordance with the present disclosure. [Figure 2E] 2B illustrates an example of a third body of the clot removal device of FIG. 2A in accordance with the present disclosure. [Figure 2F] 2B is an additional side view of the clot retrieval device of FIG. 2A in accordance with the present disclosure. [Figure 2G] 2B illustrates an exemplary third collar portion of the clot removal device of FIG. 2A in accordance with the present disclosure. [Figure 3A] 10A-10C show additional exemplary clot retrieval devices having a spring in a compressed configuration according to the present disclosure. [Figure 3B] FIG. 3B illustrates the clot retrieval device of FIG. 3A with the spring in an extended configuration, in accordance with the present disclosure. [Figure 4] FIG. 1B is a flow diagram outlining a method for capturing a blood clot using the blood clot retrieval device of FIGS. 1A-1G. [Figure 5] FIG. 2C is a flow diagram outlining a method for capturing a blood clot using the blood clot retrieval device of FIGS. 2A-2G. DETAILED DESCRIPTION OF THE INVENTION

[0029] The designs and functionality described in this application are intended to be exemplary in nature and are not intended to limit the disclosure in any way. Those skilled in the art will recognize that the teachings of the disclosure may be embodied in a variety of suitable forms, including those disclosed herein and additional forms known to those skilled in the art.

[0030] While specific embodiments of the present disclosure have been illustrated and described, it will be apparent from the foregoing description that various changes can be made therein without departing from the spirit and scope of the present disclosure. For example, while the embodiments described herein refer to particular features, the present disclosure includes embodiments having different combinations of 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, where like reference numbers indicate identical or functionally similar elements.

[0031] The terms "distal" or "proximal" are used in the following description with reference to a position or direction relative to the treating physician. "Distal" or "distally" is a position away from the physician or a direction away from the physician. "Proximal" or "proximally" or "near" is a position closer to the physician or a direction toward the physician.

[0032] In the following description, numerous specific details are set forth. However, it should be understood that examples of the disclosed technology may be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure an understanding of this description. References to "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," "particular embodiments," "various embodiments," "one example," "example," "some examples," "particular examples," "various examples," and the like, indicate that, although embodiment(s) and / or example(s) of such disclosed technology may include a particular feature, structure, or characteristic, not all embodiments necessarily include the particular feature, structure, or characteristic. Furthermore, repeated use of phrases such as "in one embodiment" does not necessarily refer to the same embodiment, example, or implementation, although it may.

[0033] "Comprising" or "containing" or "including" or "having" means that at least the specified compound, element, particle, structure, or method step is present in a composition or device or method, but does not exclude the presence of other compounds, materials, particles, method steps, or structures, even if they have the same function as the name.

[0034] Throughout this specification and claims, the following terms have at least the meaning explicitly associated therewith, unless the context clearly dictates otherwise. The term "or" is intended to mean an inclusive "or." Furthermore, the terms "a," "an," and "the" are intended to mean one or more unless otherwise specified or unless the singular form is clearly intended from the context.

[0035] Unless otherwise specified, the use of ordinal adjectives such as "first," "second," "third," etc. to describe general objects merely indicates that different instances of similar objects are being referred to and is not intended to imply that the objects so described should be in a given order in time, space, ranking, or in any other manner.

[0036] As used herein, the term "about" or "approximately" with respect to any numerical value or range of values ​​indicates a suitable dimensional tolerance that enables a portion of a component or a collection of components to function in accordance with its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value, for example, "about 90%" may refer to a range of values ​​of 71% to 99%.

[0037] As discussed herein, a "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. As an example, the animal can be a laboratory animal (e.g., rats, dogs, pigs, monkeys, etc.) specifically selected to have certain characteristics similar to humans.

[0038] Accessing various blood vessels within the vasculature, whether coronary, pulmonary, or cerebral, involves well-known procedural steps and the use of numerous conventional, commercially available accessory products. These products, such as angiographic contrast agents and guidewires, are widely used in diagnostic and medical procedures. When these products are used with the systems and methods of the present disclosure in the following description, their function and exact configuration will not be described in detail.

[0039] The disclosed technology generally can include a clot removal device having a sliding cage (e.g., a first body) and an outer cage (e.g., a second body) radially surrounding the sliding cage. The pull wire can be secured to the sliding cage such that, when tension is applied to the pull wire, the sliding cage can be displaced proximally and independently of the outer cage. When the sliding cage is displaced proximally, the sliding cage and the outer cage can sandwich the clot. In some cases, the clot removal device can further include an inner channel (e.g., a third body). The outer cage and the sliding cage can radially surround the inner channel. When tension is applied, the inner channel can move proximally and independently of the outer cage and the sliding cage. The sliding cage can then move proximally relative to the outer cage and independently of the outer cage. In such a configuration, the sliding cage and the outer cage can further sandwich the clot, thereby further incorporating the clot within the clot removal device. Therefore, efficient and effective removal of blood clots from blood vessels can be achieved.

[0040] 1A and 1B show side views of an exemplary clot retrieval device 100 in a clot engaging configuration. The clot retrieval device 100 can include a first expandable framework 102 and a second expandable framework 104. The first expandable framework 102 can include a first plurality of struts 106, and the second expandable framework 104 can include a second plurality of struts 108.

[0041] The first expandable framework 102 and the second expandable framework 104 may be collapsible within a constraining sheath (e.g., a microcatheter) sized to traverse a clot or other obstruction. The clot retrieval device 100 may be positioned proximate to a clot within a blood vessel. Optionally, the clot retrieval device 100 may traverse the clot such that a portion of the clot removal device 100 is anterior relative to the clot. The first expandable framework 102 and the second expandable framework 104 may each be configured to self-expand upon release from the constraining sheath. Upon release, the clot retrieval device 100 may transition from a constrained delivery configuration to a clot engaging configuration, such that the clot retrieval device 100 may be used to facilitate clot removal, blood flow restoration, and / or fragmentation protection.

[0042] Upon transitioning to the clot-engaging configuration, the first plurality of struts 106 of the first expandable framework 102 can expand to form a first body 110. Similarly, the second plurality of struts 108 of the second expandable framework 104 can expand to form a second body 112. The second body 112 can at least partially radially surround the first body 110. Optionally, the second body 112 can completely radially surround the first body 110.

[0043] Both the first expandable framework 102, including the first plurality of struts 106, and the second expandable framework 104, including the second plurality of struts 108, are preferably fabricated from materials capable of automatically recovering their shape upon release from a constrained delivery configuration. Superelastic or pseudoelastic materials, such as nitinol or alloys with similar properties, are particularly suitable. The materials can have a high recoverable strain sufficient to elastically collapse and expand as described herein. The materials can be in many forms, such as wire, strip, sheet, or tube. A particularly suitable manufacturing process is to laser cut a nitinol tube, then heat treat and electropolish the resulting structure to create the framework of struts and connecting elements. For example, the first expandable framework 102 and the second expandable framework 104 can each be laser cut from a nitinol tube having an outer diameter of approximately 0.40 millimeters. The first and second expandable frameworks 102, 104 can be any of a range of shapes as would be understood by one of ordinary skill in the art following the teachings disclosed herein. The first and second expandable frameworks 102, 104 can be visualized under fluoroscopy by the addition of alloying elements or by various other coatings or marker bands. For example, the first and second expandable frameworks 102, 104 can include materials and / or markers having radiopaque materials, including, but not limited to, barium sulfate, bismuth subcarbonate, barium oxychloride, gold, tungsten, platinum, iridium, tantalum, and alloys thereof. Specifically, in some examples, the first and second expandable frameworks 102, 104 can include radiopaque markers having an iridium alloy, more specifically, a platinum-iridium alloy.

[0044] 1A and 1B, in the clot-engaging configuration, the first body 110 and the second body 112 can each have a substantially cylindrical shape. Further, the first body 110 can have a first inner diameter 134, and the second body 112 can have a second inner diameter 136. The first inner diameter 134 can be approximately the same as the second inner diameter 136 so that the first body 110 and the second body 112 can be substantially aligned with each other. By way of example, the first inner diameter 134 of the first body can be approximately 4.75 millimeters, and the second inner diameter 136 can be approximately 5 millimeters. Because the first body 110 and the second body 112 have substantially equal inner diameters 132, 134, the first body 110 can apply an outward force to the second body 112 in the clot-engaging configuration.

[0045] 1A and 1B show the first body 110 and the second body 112 in a first position. The first plurality of struts 106 can form a first plurality of scaffold segments 138a having closed cells, and the second plurality of struts 108 of the second body 112 can form a second plurality of scaffold segments 138b also having closed cells. The first plurality of scaffold segments 138a and the second plurality of scaffold segments 138b can be substantially aligned with one another. Gaps can be formed between each scaffold segment of the first and second plurality of scaffold segments 138a, 138b. Such gaps can be clot-receiving spaces 120 configured to receive a blood clot. A portion of the blood clot can enter such clot-receiving space 120 and thereby be captured by the clot retrieval device 100 when the first body 110 moves from a first position to a second position relative to the second body 112, as discussed further herein.

[0046] The distal ends of first body 110 and second body 112 can form a distal basket 122. Distal basket 122 can have a substantially conical shape and can reduce and / or prevent captured clot fragments from migrating from clot retrieval device 100.

[0047] As further shown in FIGS. 1C and 1D , the proximal end of the clot retrieval device 100 can include a shaft 132 including a pull wire 114 surrounded by an outer sheath 116. As shown in FIG. 1D , a proximal strut of the first plurality of struts 106 can be secured to the pull wire 114. The pull wire 114 can be made of stainless steel, MP35N, Nitinol, or other materials with a suitably high modulus and tensile strength. The pull wire 114 preferably has a solid core, but can also have a hollow core. The first plurality of struts 106 of the first body 110 can be secured to the pull wire 114 at a junction 130 via welding, bonding, by being cut from an adjacent tube, or by other attachment means. The junction 130 can be made approximately at the location of the attachment of the proximal strut of the first plurality of struts 106 to the pull wire 114. Such a joint 130 can inhibit unintended movement of the first body 110 beyond a desired position as it moves relative to the second body 112, as discussed further herein. The second plurality of struts 108 of the second body 112 can be joined to the outer sheath 116 by welding, bonding, or the second body 112 can be formed using the same nitinol or other material tube as the outer sheath 116. Because the first body 110 and the second body 112 are affixed to separate portions of the shaft 132 (e.g., the pull wire 114 and the outer sheath 116, respectively), the first body 110 and the second body 112 can move independently of one another when tension is applied to the pull wire 114, as discussed further herein.

[0048] FIG. 1E shows an enlarged view of the substantially aligned first and second bodies 110, 112, including optional radially extending struts 126 and eyelets 124 to constrain the range of sliding movement between the first and second bodies 110, 112. As shown, the second body 112 can radially surround the first body 110, such that the second plurality of struts 108 are outboard of the first plurality of struts 106. The second plurality of struts 108 can further include one or more eyelets 124, and the first plurality of struts 106 can include one or more radially extending "connector" struts each extending through a respective eyelet 124. Each eyelet 124 can have an elongated opening or an opening of an alternative shape. By way of example, the eyelets 124 can be substantially oval, circular, rectangular, etc. In some examples, the eyelets 124 can be substantially tapered.

[0049] 1F and 1G show side views of the clot retrieval device 100 in a clot clamping configuration in which the first body 110 moves (e.g., slides) from a first position as shown in FIGS. 1A and 1B relative to the second body 112 to a second position. The pull wire 114 can be pulled proximally to apply tension. The tension can move the first body 110 from the first position ( FIGS. 1A and 1B ) to the second position ( FIGS. 1F and 1G ) relative to the second body 112. Thus, the first body 110 can slide from the first position to the second position relative to the second body 112 such that the first body 110 and the second body 112 engage with each other. For example, the first body 110 can slide less than about 5 millimeters relative to the second body 112. Optionally, the first body 110 can slide less than about 4 millimeters relative to the second body 112. Optionally, first body 110 can slide less than about 2 millimeters relative to second body 112. Optionally, first body 110 can slide less than about 0.5 millimeters relative to second body 112. When first body 110 moves from the first position to the second position, and device 100 includes one or more radially extending struts 126 passing through respective eyelets 124, as shown in FIG. 1E, radially extending struts 126 can engage with eyelets 124, causing first body 110 and second body 112 to engage with one another. Furthermore, eyelets 124 can limit radially extending struts 126 from moving too far in the proximal direction, thereby preventing first body 110 from moving beyond the second position relative to second body 112.

[0050] Additionally or alternatively, the first expandable framework 102 and the second expandable framework 104 can be coated with a polymeric coating (e.g., parylene) to temporarily hold the first body 110 in a first position relative to the second body 112. When the pull wire 114 is pulled proximally, the polymeric coating can prevent the first body 110 from moving from the first position to the second position relative to the second body 112. Suction can be applied to remove particles from the immobilized polymeric coating.

[0051] Additionally or alternatively, the shape memory effect of the first body 110 and the second body 112 can be used to cause automatic displacement of the first body 110 after a predetermined time has elapsed. For example, the second plurality of struts 108 of the second expandable framework 104 can be locally heat treated to raise the austenite finish temperature to a range above typical body temperature during a stroke or other critical physical event. The second plurality of struts 108 expand when re-sheathed and can then be heated to the austenite finish temperature by an electric current. Upon reaching the austenite finish temperature, the first body 110 can automatically move (e.g., slide) from a first position to a second position relative to the second body 112, and the blood clot can be trapped between the first body 110 and the second body 112.

[0052] The pull wire 114 can be pulled proximally to cause the first body 110 to move (e.g., slide) proximally until a proximal strut of the first plurality of struts 106 encounters a junction 130 positioned near the shaft 132. Thus, the junction 130 can function as a mechanism for preventing undesired movement beyond the second position. As the first body 110 moves from the first position to the second position, the average cross-sectional area of ​​the plurality of clot-receiving spaces 120 can decrease (e.g., at least partially close). For example, when the first plurality of scaffold segments 138a slide relative to the second plurality of scaffold segments 138b such that the first plurality of scaffold segments 138a are disposed across the clot-receiving spaces 120, the plurality of clot-receiving spaces 120 can at least partially close. A clot can thereby be trapped between the first body 110 and the second body 112. Because clamping can increase the gripping force of clot retrieval device 100 compared to other clot retrieval devices, clamping the clot can prevent the clot from migrating from clot retrieval device 100, particularly upon retraction of clot retrieval device 100, especially for fibrin-rich clots. Thus, clot retrieval device 100 can ensure effective and efficient removal of the clot from the patient.

[0053] 1F and 1G, the clot retrieval device 100 can include a polymer membrane 128 disposed between the first body 110 and the second body 112. The polymer membrane 128 (e.g., an elastic membrane) can be configured to transition from a collapsed configuration when the first body 110 is in the first position such that the first body 110 and the second body 112 disengage into an extended configuration as the first body 110 moves from the first position to the second position. The polymer membrane 128 can thereby function to limit lateral movement of the first body 110 relative to the second body 112 in addition to, or as an alternative to, the radially extending struts 126 and eyelets 124 shown in FIG. 1E. The polymer membrane 128 can be formed by threading microfibers through the eyelets 124 of the second body 112 and / or by hooking the polymer membrane 128 within the eyelets 124. Polymer membrane 128 can prevent a clot from migrating out of clot retrieval device 100 once the clot is sandwiched between first body 110 and second body 112. While Figures 1F and 1G show polymer membrane 128 in one location, it is contemplated that clot retrieval device 100 can include additional polymer membranes 128 in multiple locations. For example, clot retrieval device 100 can include a first polymer membrane proximate distal basket 122 and a second polymer membrane proximate shaft 132.

[0054] 2A shows an additional exemplary clot retrieval device 200. As discussed above with reference to the clot retrieval device 100 shown in FIGS. 1A-1G, the clot retrieval device 200 may similarly comprise a first expandable framework 102 including a first plurality of struts 106 and a second expandable framework 104 including a second plurality of struts 108. When the clot retrieval device 200 is deployed from a constraining sheath (e.g., a microcatheter) and transitions from a constrained delivery configuration to a clot-engaging configuration, the first plurality of struts 106 of the first expandable framework 102 may self-expand to form a first body 110, and the second plurality of struts 108 of the second expandable framework 104 may self-expand to form a second body 112. The first body 110 and the second body 112 may be substantially cylindrical. Additionally, the first body 110 and the second body 112 can have substantially equal inner diameters 134, 136. Thus, as described above, the multiple scaffold sections 138a, 138b of the first body 110 and the second body 112 can be substantially aligned with one another.

[0055] 1A-1G , the clot retrieval device 200 can further include a third expandable framework 202 having a third plurality of struts 204. When the clot retrieval device 200 is deployed from the constraining sheath, the third plurality of struts 204 of the third expandable framework 202 can self-expand to form a third body 206. The third body 206 can be substantially porous. Furthermore, the third body 206 can also be substantially cylindrical and have an inner diameter 238 that is smaller than the inner diameters 134 and 136 of the first and second bodies 110 and 112. This allows the first and second bodies 110 and 112 to radially surround the third body 206. Optionally, the third body 206 can have an inner diameter 238 that is approximately half (½) the size of the inner diameter 134 of the first body 110 and the inner diameter 136 of the second body 112. Optionally, the third body 206 can have an inner diameter 238 that is approximately three-quarters (¾) the size of the inner diameter 134 of the first body 110 and the inner diameter 136 of the second body 112. The third expandable framework 202 can preferably be fabricated from a material that can automatically recover its shape when released from a constrained delivery configuration. Superelastic or pseudoelastic materials, such as nitinol or alloys with similar properties, are particularly suitable. The material can have a high recoverable strain sufficient to elastically collapse and expand as described herein. The material can be in many forms, such as a wire, strip, 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 connecting elements. Optionally, the third expandable framework 202 can be laser cut from the nitinol tube.

[0056] As discussed above with respect to clot retrieval device 100, first body 110 can include a first plurality of scaffold segments 138a, and second body 112 can include a second plurality of scaffold segments 138b. The first and second plurality of scaffold segments 138a, 138b can be substantially aligned with one another. Gaps can be formed between each scaffold segment of the first plurality of scaffold segments 138a, 138b and the second plurality of scaffold segments 138a, 138b. Such gaps can be clot-receiving spaces 120 configured to receive at least a portion of a clot when clot retrieval device 200 transitions to the clot clamping configuration, as described further herein. The configuration of third body 206 can similarly create additional clot-receiving spaces 230, as discussed further herein.

[0057] The distal end of clot retrieval device 200 can include a distal basket 122. Distal basket 122 can have a substantially conical shape and can mitigate displacement of captured fragments of the clot from clot retrieval device 200.

[0058] 2B , the plurality of expanded struts 208 a, 208 b can be formed from the shaft 216 of the first body 110. For example, the shaft 216 of the first body 110 can be a tube (e.g., a nitinol tube), and the two expanded struts 208 a, 208 b can be formed (e.g., laser cut) from such a tube. The shaft 216 of the first body 110 can be a hollow tube sized to receive the pull wire 114. Thus, the pull wire 114 can extend through the shaft 216 of the first body 110. The plurality of expanded struts 208 a, 208 b can facilitate improved clamping when the clot retrieval device 200 is transitioned to the clot clamping configuration. Optionally, if effective clamping is not achieved when the clot retrieval device 200 transitions to the clot clamping configuration, multiple expanded struts 208a, 208b can be used to allow re-expansion of the third body 206 to stabilize the clot. The shaft 222 of the second body 112 can surround the shaft 216 of the first body 110 and the pull wire 114. The shaft 222 of the second body 112 can be a tube (e.g., a nitinol tube). The proximal strut 224 of the second body 112 can extend from the distal end of the shaft 222 of the second body 112. The proximal strut 224 can be the proximal-most strut of the second expandable framework 104. The proximal end of the shaft 218 of the third body 206 can be anchored to the distal end of the pull wire 114. The shaft 218 of the third body 206 can be a solid core tube. The shaft 218 of the third body 206 can be secured to the pullwire 114, forming a joint 220 (e.g., a weld joint) where the shaft 216 of the first body 110 forms the expanded struts 208a, 208b. The proximal strut 226 of the third body 206 can extend from the distal end of the shaft 218 of the third body 206. The proximal strut 226 can be the proximal-most strut of the third expandable framework 202.

[0059] 2C-2E illustrate various configurations of the third body 206. In FIGS. 2C-2E, the third plurality of struts 204 can be configured to form a substantially cylindrical body of interconnected struts. The third plurality of struts 204 can be interconnected to one another such that the third plurality of struts form a majority of closed cells. The third plurality of struts 204 can be configured to form closed cells of different sizes. Optionally, the closed cells can be sized depending on the content of the captured clot (e.g., based on how soft and / or fibrin-rich the captured clot is). As shown in FIGS. 2C-2E, the third body 206 can further include a plurality of clot-receiving spaces 230. The size of each clot-receiving space 230 can be based on the configuration of the third plurality of struts 204. Optionally, as shown in FIGS. 2C and 2E, the third plurality of struts 204 can include at least one sectioned strut 204a. The cut struts can form open cells. Such open cells can form larger clot-receiving spaces 230, thereby facilitating migration of the clot into third body 206. Optionally, third plurality of struts 204 can include multiple cut struts 204a such that the majority of the cells are open cells. Third body 206 can serve two primary functions. For example, third body 206 can facilitate the passage of blood so that there is at least partial blood flow through the vessel when a clot is captured and extracted by clot retrieval device 200. Furthermore, when clot retrieval device 200 is deployed, the clot can become partially incorporated into clot-receiving spaces 120 of first body 110 and second body 112. As the third body 206 moves (e.g., slides) relative to the first body 110 and the second body 112, the third body 206 can interact with the clot, thereby promoting further incorporation of the clot between the first body 110 and the second body 112 before forming a clamp.

[0060] 2F shows an additional side view of clot retrieval device 200. As shown in FIG. 2F, first body 110 can include a first collar portion 210, second body 112 can include a second collar portion 212, and third body 206 can include a third collar portion 214. Respective collar portions 210, 212, 214 can facilitate moving (e.g., sliding) third body 206 relative to first body 110 and second body 112, and subsequently moving (e.g., sliding) first body 110 relative to second body 112 to clamp at least a portion of the clot. The pull wire 114 can be fixed to the third body 206 and can be threaded through each of the collar portions 210, 212, 214 so that when the pull wire 114 is pulled proximally, the clot retrieval device 200 can move (e.g., slide) from a first position to a second position, and subsequently from the second position to a third position.

[0061] 2G illustrates an exemplary third collar portion 214. Third collar portion 214 may be disposed to couple expanded struts 208 a, 208 b. Third collar portion 214 may be laser cut with a specific design to facilitate clamping of the clot as clot retrieval device 200 moves from the first position to the second position, and subsequently from the second position to the third position.

[0062] To clamp a clot using clot retrieval device 200, pull wire 114 can be pulled proximally. Such tension can cause third body 206 to move (e.g., slide) relative to first body 110 and second body 112, as indicated by first arrow 232, transitioning clot retrieval device 200 from a first position to a second position. For example, third body 206 can slide less than about 5 millimeters relative to first body 110 and second body 112. Optionally, third body 206 can slide less than about 4 millimeters relative to first body 110 and second body 112. Optionally, third body 206 can slide less than about 2 millimeters relative to first body 110 and second body 112. Optionally, third body 206 can slide less than about 0.5 millimeters relative to first body 110 and second body 112.

[0063] As third body 206 moves relative to first body 110 and second body 112, at least a portion of the clot may be trapped between third body 206 and first body 110 and second body 112, displacing a portion of the clot into first body 110 and second body 112. Additionally, as third body 206 moves from the first position to the second position, third body 206 may engage first body 110 when third collar portion 214 engages first collar portion 210. When third collar portion 214 and first collar portion 210 are engaged, a pulling force may be transmitted to first body 110, thereby enabling further displacement.

[0064] Thereafter, first body 110 can move (e.g., slide) relative to second body 112 such that clot retrieval device 200 transitions from the second position to a third position, as indicated by second arrow 234. For example, first body 110 can slide less than about 5 millimeters relative to second body 112. Optionally, first body 110 can slide less than about 4 millimeters relative to second body 112. Optionally, first body 110 can slide less than about 2 millimeters relative to second body 112. Optionally, first body 110 can slide less than about 0.5 millimeters relative to second body 112.

[0065] When the first body 110 moves from the second position to the third position, the first body 110 engaged with the third body 206 can engage with the second body 112 to reduce (e.g., at least partially close) the average cross-sectional area of ​​the plurality of clot-receiving spaces 120. This can further sandwich at least a portion of the clot. A portion of the clot can be sandwiched between the first body 110 and the second body 112, and further between the third body 206. Thus, a portion of the clot can move further within the third body 206. Thus, a portion of the clot can move further into the clot-receiving space 230 of the third body 206. Upon transitioning to the third position, the expanded struts 208a, 208b can again be retracted into the sheath when the first collar portion 210 engages with the second collar portion 212. When first collar portion 210 is engaged with second collar portion 212, a pulling force can be transmitted to second body 112. Thus, first body 110, second body 112, and third body 206, including the captured clot or portion thereof, can be simultaneously removed from the patient's vasculature.

[0066] Optionally, clot retrieval device 200 can include a seal that allows clot retrieval device 200 to maintain clamping even when the physician stops applying tension. For example, clot retrieval device 200 can include a seal disposed proximate weld joint 220. The seal can use friction to maintain clot retrieval device 200 in place. Thus, the seal can create sufficient static friction to prevent clot removal device 200 from displacing when the physician stops applying tension, while ensuring that static friction is not too high for a user to overcome during manipulation of clot retrieval device 200 and removal of clot retrieval device 200 from the patient during clot retrieval.

[0067] 3A and 3B show a further exemplary clot retrieval device 300. The clot retrieval device 300 can have a constrained delivery configuration and a clot engagement configuration and can be configured to remove a clot (e.g., a thrombus) T from a blood vessel. The clot removal device 300 can be in the constrained delivery configuration when the clot removal device 300 is positioned within a constraining sheath (e.g., a microcatheter). When the constraining sheath is retracted, the clot removal device 300 can transition to the clot engagement configuration. The clot retrieval device 300 can include an inner expandable framework 302 and an outer expandable framework 304. The inner expandable framework 302 can include a plurality of inner struts 306 that self-expand to form an inner body 310 when the clot retrieval device 300 transitions from the constrained delivery configuration to the clot engagement configuration. Similarly, outer expandable framework 304 may include a plurality of outer struts 308 that self-expand to form outer body 312 when clot retrieval device 300 transitions from a constrained delivery configuration to a clot engaging configuration. Inner expandable framework 302 and outer expandable framework 304 may preferably be fabricated from a material that can automatically recover its shape when released from a constrained delivery configuration, and further include additional properties as described above with reference to first expandable framework 102 and second expandable framework 104.

[0068] The inner body 310 and the outer body 312 can have different inner diameters 330, 332 and / or configurations. For example, the inner body 310 can have an inner diameter 330 that is smaller than the inner diameter 332 of the outer body 312, such that the outer body 312 can radially surround the inner body 310. Optionally, the inner diameter 330 of the inner body 310 can be approximately half the size of the inner diameter 332 of the outer body 312. Optionally, the inner diameter 330 of the inner body 310 can be approximately three-quarters the size of the inner diameter 332 of the outer body 312. As shown in FIG. 3A , the different diameters 330, 332 and configurations of the inner body 310 and the outer body 312 can form multiple clot-receiving spaces 320 configured to engage a blood clot T. For example, the outer body 312 can include multiple scaffold sections. A clot-receiving space 320 can be formed between each scaffold section 338 of the multiple scaffold sections. Additionally, inner body 310 may have a substantially "S" waveform. Such an "S" waveform may facilitate clamping and capturing a clot as inner body 310 moves relative to outer body 312, and, once the clot is captured, may facilitate preventing the captured clot from migrating out of clot retrieval device 300.

[0069] The inner body 310 and the outer body 312 can each be secured to a pull wire 314. The pull wire 314 can include a first stop 322 and a second stop 324 at a proximal end 326 of the pull wire. The first stop 322 can be disposed distally relative to the second stop 324.

[0070] The spring 316 may be affixed to the distal end 318 of the pull wire 314. The spring 316 may be configured to transition between a compressed configuration and an extended configuration upon actuation. The spring 316 may be configured to maintain a centered position of the inner body 310 within the outer body 312. In the previously illustrated clot retrieval devices 100, 200, the first body 110 has an inner diameter 134 that is approximately equal to the second body 112, so that the outward force from the first body 110 to the second body 112 causes the first body 110 to be centered within the second body 112. As shown in FIGS. 3A and 3B, if the inner body 310 has an inner diameter 330 that is substantially smaller than the outer body 312, a distal portion of the inner body 310 can deflect radially relative to the outer body 312, but the spring 316 prevents the distal portion from deflecting. The spring 316 can further function to hold the device 300 in the first position when the pull wire 314 is not under tension.

[0071] 3A , clot retrieval device 300 can be positioned proximate to clot T. At least a portion of clot retrieval device 300 can traverse clot T such that a distal end of clot retrieval device 300 can be forward relative to clot T. Pull wire 314 can be pulled proximally to move (e.g., slide) inner body 310 from a first position to a second position relative to outer body 312.

[0072] 3B shows the clot retrieval device 300 transitioning to a clot clamping configuration as the inner body 310 moves from a first position to a second position. The pull wire 314 can be pulled proximally until the first stop 322 approaches and / or engages the second stop 324 (e.g., is at or within a predetermined distance of the second stop 324), which can then serve as an indicator of when to stop applying tension to the pull wire 314 and / or when to gradually reduce the amount of tension being applied to the pull wire 314. Pulling the pull wire 314 proximally can activate the spring 316, transitioning the spring 316 from a compressed configuration to an extended configuration. The transition of the spring 316 to the extended configuration allows the inner body 310 to move from the first position to the second position. Such movement from the first position to the second position can reduce (e.g., at least partially close) the average cross-sectional area of ​​the clot-receiving space 320, thereby sandwiching the clot T between the inner body 310 and the outer body 312. Once the clot T is sandwiched between the inner body 310 and the outer body 312, the inner body 310 and the outer body 312, including the clot T, can be retracted into a constraining sheath (e.g., a microcatheter), after which the clot retrieval device 300 can be removed from the patient.

[0073] 4 shows a flow diagram outlining a method 400 of capturing a clot using the clot retrieval device 100 shown in FIGS. 1A-1G. The method 400 may include deploying 402 the clot retrieval device 100 in proximity to a clot. As discussed herein, the clot retrieval device 100 may include a first expandable framework 102 and a second expandable framework 104. Upon deployment of the clot retrieval device 100, the clot retrieval device 100 may transition from a constrained delivery configuration to a clot-engaging configuration, wherein the first expandable framework 102 expands to form a first body 110, while the second expandable framework 104 expands to form a second body 112 that radially surrounds the first body 110. The first body 110 and the second body 112 may have substantially the same inner diameters 134, 136 such that the first body 110 and the second body 112 are substantially radially aligned with one another.

[0074] The method 400 may further include moving 404 (e.g., sliding) the first body 110 proximally relative to the second body 112 to sandwich at least a portion of the clot between the first body 110 and the second body 112, such that the clot removal device 100 transitions to a clot-clamping configuration. By way of example, tension may be applied to the pull wire 114 until the first body 110 encounters the junction 130. As the pull wire 114 is pulled proximally, the first body 110 may move proximally relative to the second body 112, thereby sandwiching at least a portion of the clot between the first body 110 and the second body 112.

[0075] The method 400 may further include capturing 406 one or more fragments of the clot.

[0076] Additionally, the method 400 can include simultaneously retracting the first body 110 and the second body 112 as the first body 110 and the second body 112 engage when the first body 110 moves relative to the second body 112. Similarly, once the first body 110 and the second body 112 are retracted into the constraining sheath, the constraining sheath can be removed from the patient's vasculature.

[0077] 5 shows a flow diagram outlining a method 500 of capturing a clot using the clot retrieval device 200 shown in FIGS. 2A-2F . The method 500 may include deploying 502 the clot retrieval device 200 in proximity to a clot. As discussed herein, the clot retrieval device 100 may include a first expandable framework 102, a second expandable framework 104, and a third expandable framework 202. Upon deployment of the clot retrieval device 200, the clot retrieval device 200 may transition from a constrained delivery configuration to a clot-engaging configuration, wherein the first expandable framework 102 expands to form a first body 110, while the second expandable framework 104 expands to form a second body 112 that radially surrounds the first body 110. The first body 110 and the second body 112 can have substantially the same inner diameters 134, 136 such that the first body 110 and the second body 112 can be substantially aligned with one another. Similarly, the third expandable framework 202 can expand to form the third body 206. The first body 110 and the second body 112 can radially surround the third body 206 such that the third body 206 can have a smaller inner diameter 238 compared to the first body 110 and the second body 112.

[0078] The method 500 may further include moving 504 (e.g., sliding) the third body 206 relative to the first body 110 and the second body 112 to sandwich at least a portion of the clot between the third body 206 and the first body 110 and the second body 112, such that the clot removal device 200 transitions to a clot-clamping configuration. Thus, at least a portion of the clot may move into the first body 110 and the second body 112. Moving the third body 206 relative to the first body 110 and the second body 112 may cause the third body 206 to engage with the first body 110.

[0079] The method 500 may further include moving 506 (e.g., sliding) the first body 110 proximally relative to the second body 112 to further pinch at least a portion of the clot between the third body 206 and the first and second bodies 110, 112. As the first body 110 moves relative to the second body 112, the average cross-sectional area of ​​the clot-receiving space 120 may decrease, thereby pinching at least a portion of the clot and preventing and / or mitigating migration of the captured portion of the clot rearwardly out of the clot retrieval device 200. Upon pinching the clot, at least a portion of the clot may migrate inside the third body 206. When at least a portion of the clot is within the third body 206, the likelihood of migration of the captured portion of the clot rearwardly out of the clot retrieval device 200 may be reduced.

[0080] The method 500 may further include capturing 508 one or more fragments of the clot.

[0081] Further, the method 500 can include simultaneously retracting the first body 110, the second body 112, and the third body 206. Once retracted into the delivery microcatheter, the delivery microcatheter can be removed from the patient's vasculature, thereby effectively and efficiently removing the clot from the patient's vasculature.

[0082] Specific examples and implementations of the disclosed technology have been described above with reference to block diagrams and flow diagrams according to embodiments of the disclosed technology. It will be understood that one or more blocks of the block diagrams and flow diagrams, as well as combinations of blocks in the block diagrams and flow diagrams, respectively, may be performed. Similarly, according to some examples or implementations of the disclosed technology, some blocks of the block diagrams and flow diagrams do not necessarily need to be performed in the order presented, may be repeated, or need not necessarily be performed. It should also be understood that a reference to one or more method steps does not exclude the presence of additional or intervening method steps between those explicitly identified steps. Furthermore, method steps from one process flow diagram or block diagram can be combined with method steps from another process diagram or block diagram. These combinations and / or variations are contemplated herein.

[0083] [Embodiment] (1) A clot retrieval device configured to remove a clot from a blood vessel, the device comprising: a constrained delivery configuration and a clot engagement configuration; a first expandable framework including a first plurality of struts forming a first body; a second expandable framework including a second plurality of struts forming a second body at least partially surrounding the first body; A clot retrieval device, wherein in the clot engagement configuration, the first body is configured to move from a first position to a second position relative to the second body. (2) A clot retrieval device as described in embodiment 1, wherein the first body has a first inner diameter, the second body has a second inner diameter, and the first inner diameter and the second inner diameter are substantially equal. (3) A clot retrieval device as described in embodiment 1, wherein when the first body is in the first position, the first plurality of struts and the second plurality of struts are disengaged to form multiple clot receiving spaces. (4) A clot retrieval device as described in embodiment 3, wherein when the first body is in the second position, the first plurality of struts and the second plurality of struts are engaged, and when the first body moves from the first position to the second position, the average cross-sectional area of ​​the plurality of clot receiving spaces decreases. (5) The clot retrieval device of embodiment 1, wherein the first plurality of struts includes at least one radially extending strut, the second plurality of struts includes at least one eyelet, the at least one radially extending strut extending radially through the eyelet, and the at least one eyelet and the at least one radially extending strut are configured such that when the first body moves from the first position to the second position, the at least one radially extending strut engages with the at least one eyelet to prevent movement of the first plurality of struts beyond the second position relative to the second plurality of struts.

[0084] (6) A clot retrieval device as described in embodiment 5, wherein each eyelet is tapered. (7) The clot retrieval device of embodiment 1, further comprising a polymeric coating for engaging the first plurality of struts and the second plurality of struts, the polymeric coating being configured to prevent the first body from moving from the first position to the second position. (8) A clot retrieval device as described in embodiment 1, further comprising at least one polymer membrane attached to the first plurality of struts and the second plurality of struts, the polymer membrane being disposed between the first body and the second body. (9) A clot retrieval device as described in embodiment 8, wherein when the first body is in the first position, the at least one polymer membrane is in a folded configuration, and when the first body moves proximal to the second position, the at least one polymer membrane transitions to an extended configuration. (10) The clot retrieval device of embodiment 1, further comprising a third expandable framework including a third plurality of struts forming a third body, wherein the first body and the second body at least partially surround the third body in the clot engaging configuration.

[0085] (11) A clot retrieval device according to embodiment 10, wherein the third body is configured to move relative to the first body and the second body. (12) A clot retrieval device as described in embodiment 10, wherein the proximal end of the clot retrieval device includes a plurality of extended struts forming a collar portion. (13) A blood clot retrieval device as described in embodiment 10, wherein the third plurality of struts includes at least one cut strut. (14) A clot retrieval device as described in embodiment 10, wherein the third body includes a plurality of clot receiving spaces, and the plurality of clot receiving spaces are configured to engage the clot. (15) A clot retrieval device configured to remove a clot from a blood vessel, the device comprising: a constrained delivery configuration and a clot engagement configuration; an inner expandable framework including a plurality of inner struts secured to the pull wires and forming an inner body; an outer expandable framework including a plurality of outer struts attached to the pull wires and forming an outer body at least partially surrounding the inner body; a spring secured proximate a distal end of the pull wire, the spring having a compressed configuration and an extended configuration; A clot retrieval device, wherein in the clot engagement configuration, the inner body is configured to move from a first position to a second position relative to the outer body, and the spring transitions from the compressed configuration to the extended configuration.

[0086] (16) The clot retrieval device of embodiment 15, wherein the outer expandable framework includes a plurality of clot receiving spaces configured to sandwich the clot between the inner body and the outer body when the inner body moves from the first position to the second position. (17) A method for capturing a blood clot, the method comprising: deploying a clot retrieval device adjacent to the clot, the clot retrieval device including a first expandable framework forming a first body and a second expandable framework forming a second body at least partially surrounding the first body; moving the first body relative to the second body to sandwich at least a portion of the clot between the first body and the second body; capturing one or more fragments of the clot. (18) The method of embodiment 17, wherein moving the first body relative to the second body to pinch at least a portion of the clot between the first body and the second body comprises applying tension to a pull wire, the pull wire being in mechanical communication with the first body. 19. The method of claim 17, further comprising simultaneously retracting the first body and the second body. (20) The clot retrieval device further includes a third expandable framework including a third plurality of struts forming a third body, the first body and the second body at least partially surrounding the third body, and the method further includes: 18. The method of embodiment 17, further comprising retracting the third body proximally to engage the first body and the third body.

Claims

1. 1. A clot retrieval device configured to remove a clot from a blood vessel, the clot retrieval device comprising a constrained delivery configuration and a clot engagement configuration, the clot retrieval device comprising: a first expandable framework including a first plurality of struts forming a first body; a second expandable framework including a second plurality of struts forming a second body at least partially surrounding the first body; In the clot-engaging configuration, the first body is configured to move relative to the second body from a first position to a second position; the second position is a position where the first body is displaced proximally from the first position and independently of the second body; a first plurality of struts including at least one radially extending strut, said second plurality of struts including at least one eyelet, said at least one radially extending strut extending radially through said eyelet, said at least one eyelet and said at least one radially extending strut being configured such that when said first body moves from said first position to said second position, said at least one radially extending strut engages with said at least one eyelet to prevent movement of said first plurality of struts beyond said second position, relative to said second plurality of struts.

2. The clot retrieval device of claim 1 , wherein the first body has a first inner diameter and the second body has a second inner diameter, the first inner diameter and the second inner diameter being substantially equal.

3. The clot retrieval device of claim 1 , wherein when the first body is in the first position, the first plurality of struts and the second plurality of struts are disengaged to form a plurality of clot-receiving spaces.

4. 4. The clot retrieval device of claim 3, wherein when the first body is in the second position, the first plurality of struts and the second plurality of struts are engaged, and when the first body moves from the first position to the second position, the average cross-sectional area of ​​the plurality of clot receiving spaces decreases.

5. The first body includes a plurality of cells formed by the first plurality of supports, the second body includes a plurality of cells formed by the second plurality of struts; The clot retrieval device of claim 1 , wherein when in the first position, the plurality of cells of the first body overlap the plurality of cells of the second body, as viewed from a side.

6. A blood clot retrieval device as described in claim 1, wherein each of the at least one eyelet is tapered.

7. 2. The blood clot retrieval device of claim 1, further comprising a polymeric coating for engaging the first plurality of struts and the second plurality of struts, the polymeric coating configured to prevent the first body from being able to move from the first position to the second position.

8. 2. The blood clot retrieval device of claim 1, further comprising at least one polymer membrane affixed to the first plurality of struts and the second plurality of struts, the polymer membrane being disposed between the first body and the second body.

9. 9. The clot retrieval device of claim 8, wherein when the first body is in the first position, the at least one polymer membrane is in a collapsed configuration, and when the first body is moved proximal to the second position, the at least one polymer membrane transitions to an extended configuration.

10. 2. The clot retrieval device of claim 1, further comprising a third expandable framework including a third plurality of struts forming a third body, the first body and the second body at least partially surrounding the third body in the clot engaging configuration.

11. The clot retrieval device of claim 10 , wherein the third body is configured to move relative to the first body and the second body.

12. The clot retrieval device of claim 10 , wherein the proximal end of the clot retrieval device includes a plurality of enlarged struts forming a collar.

13. The clot retrieval device of claim 10 , wherein the third plurality of struts includes at least one severed strut.

14. The clot retrieval device of claim 10 , wherein the third body includes a plurality of clot-receiving spaces, the plurality of clot-receiving spaces configured to engage the clot.

15. 1. A clot retrieval device configured to remove a clot from a blood vessel, the clot retrieval device comprising a constrained delivery configuration and a clot engagement configuration, the clot retrieval device comprising: an inner expandable framework including a plurality of inner struts attached to the pull wires and forming an inner body, the inner body including a plurality of cells formed by the plurality of inner struts; an outer expandable framework including a plurality of outer struts attached to the pull wires and forming an outer body at least partially surrounding the inner body; a spring secured proximate a distal end of the pull wire, the spring having a compressed configuration and an extended configuration; the spring extends between a distal-most cell of the plurality of cells of the inner body and a distal end of the outer body; In the clot-engaging configuration, the inner body is configured to move from a first position to a second position relative to the outer body to transition the spring from the compressed configuration to the extended configuration; The second position is a position in which the inner body is displaced proximally from the first position and independently of the outer body.

16. 16. The clot retrieval device of claim 15, wherein the outer expandable framework includes a plurality of clot-receiving spaces configured to sandwich the clot between the inner body and the outer body when the inner body is moved from the first position to the second position.

17. 1. A clot retrieval device configured to remove a clot from a blood vessel, the clot retrieval device comprising a constrained delivery configuration and a clot engagement configuration, the clot retrieval device comprising: a first expandable framework including a first plurality of struts forming a first body; a second expandable framework including a second plurality of struts forming a second body at least partially surrounding the first body; at least one polymer membrane affixed to the first plurality of struts and the second plurality of struts, the polymer membrane being disposed between the first body and the second body; A clot retrieval device, wherein in the clot engaging configuration, the first body is configured to move proximally independently from the second body.

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