Embolism retrieval system and embolism retrieval method

Abstract

A system for embolus retrieval and a method for using the system. The system includes a thrombus retrieval device having multiple foliate extensions, and a collection unit configured to transition between a folded state when isolated within an outer lumen and an expanded state when it emerges from the outer lumen, wherein the thrombus retrieval device can be taken into the collection unit when the collection unit is in the expanded state. The system may optionally include a distal capture device.

Description

Technical Field

[0001] Related Applications This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 469,460, filed on May 29, 2023, the content of which is hereby incorporated by reference in its entirety.

[0002] Technical Field The present invention relates to a system for retrieving emboli from a living blood vessel. Certain embodiments of the present invention relate to a catheter system including an embolus retrieval device for releasing and collecting an embolic substance, a collection unit for collecting the embolus retrieval device, and a distal capture device for capturing a thrombus or a part thereof during a retrieval procedure.

Background Art

[0003] Occlusion of an arterial blood vessel supplying blood to an organ such as the brain may cause conditions such as stroke and death. Therefore, removing the substance occluding the blood vessel to restore blood supply to the organ represents the first line of treatment in such cases.

[0004] To mechanically remove thrombus substances from small blood vessels, two general methods are utilized: the distal approach and the proximal approach.

[0005] In the distal approach, the distal end of the retrieval device (usually equipped with a distal basket or snare) passes through the occlusion and is positioned on the distal side thereof. Thereafter, the device is withdrawn (in the proximal direction) with the distal end engaged with the thrombus substance.

[0006] In the proximal approach, the distal end of the retrieval device (equipped with a grasper or aspirator) contacts the proximal side of the thrombus, and then the thrombus is pulled in the proximal direction through the blood vessel and finally removed outside the body. An example of a device utilizing the proximal approach is the Penumbra device manufactured by Penumbra and disclosed in EP1799128.

[0007] A third, more commonly used approach involves opening a stent-like retrieval device within the thrombus, pressing the thrombotic material against the arterial wall, and retrieving the device along with the compressed thrombotic material.

[0008] While these approaches can be used to remove at least partially the thrombotic material blocking an artery, such removal can often increase the risk of embolic fragmentation and the release of thrombotic debris. Furthermore, current approaches have the added limitation of being less effective at capturing and removing the entire embolus (J Neuroimaging 2021, Sep;31(5):912~924.doi:10.1111 / jon.1288).

[0009] Therefore, having a system that can remove occlusive substances from biological blood vessels, such as blood vessels, without the limitations mentioned above is extremely advantageous. [Overview of the Initiative]

[0010] According to one aspect of the present invention, a system for embolus retrieval is provided, comprising: a thrombus retrieval device having a plurality of leaf-like extensions; and a collection unit configured to transition between a folded state when isolated within an outer tube and an expanded state when extending from the outer tube, wherein the thrombus retrieval device is capable of being taken into the collection unit when the collection unit is in the expanded state.

[0011] According to an embodiment of the present invention, the collection unit transitions to a funnel shape when it extends from the outer tube.

[0012] According to an embodiment of the present invention, the plurality of leaf-like extensions are attached to the distal portion of the elongated body.

[0013] According to embodiments of the present invention, the plurality of leaf-like extensions unfold radially outward when they extend from the outer tube.

[0014] According to an embodiment of the present invention, the extended portion folds relative to the extended body when it extends distally, and unfolds radially outward when the extended body is retracted proximal.

[0015] According to an embodiment of the present invention, the leaf-like extension is concave.

[0016] According to embodiments of the present invention, the leaf-like extension includes a distal tip that curves inward.

[0017] According to embodiments of the present invention, the collection unit is formed from a wire mesh or a laser-cut or etched foil.

[0018] According to embodiments of the present invention, the collection unit is coated with a polymer material such as polyurethane, PTFE, or silicone.

[0019] According to embodiments of the present invention, the system further comprises a distal capture device.

[0020] According to embodiments of the present invention, the distal capture device is attached to the distal end of the thrombectomy device or can be delivered via the thrombectomy device.

[0021] According to embodiments of the present invention, the distal capture device can be delivered via the guidewire lumen of the extension.

[0022] According to embodiments of the present invention, the distal capture device, when extended, takes the shape of an umbrella, parachute, flower, spiral, or ball. According to embodiments of the present invention, the extended body is deliverable via the collection unit.

[0023] This invention successfully overcomes the shortcomings of currently known configurations by providing a device for effectively and non-traumatically retrieving occlusions such as thrombi from biological blood vessels such as arteries.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0025] The present invention is described herein by way of example only and with reference to the accompanying drawings. While referring in detail to the drawings, it is emphasized that the details shown are for purposes of illustration and are intended to provide a description of the preferred embodiments of the present invention and to provide the most useful and readily understood explanation of the principles and conceptual aspects of the invention. In this regard, no attempt has been made to show structural details more than is necessary for a basic understanding of the invention, and the description taken together with the drawings will make apparent to those skilled in the art how some forms of the invention may be actually embodied.

Brief Description of the Drawings

[0026] [Figure 1A-1C] Figures 1A to 1F are diagrams showing the complete system of the present system / kits and its individual components. Figure 1A is a diagram showing the complete system of the present system / kits, Figure 1B is a diagram showing the guide wire of the present system / kits, and Figure 1C is a diagram showing the outer tube of the collection part of the present system / kits. [Figure 1D-1F] Figure 1D is a diagram showing the collection part of the present system / kits, Figure 1E is a diagram showing the recovery device of the present system / kits, and Figure 1F is a diagram showing the distal capture device of the present system / kits in a deployed state. [Figure 2] Figures 2A to 2E are diagrams showing the use of the present system when collecting embolic substances from blood vessels. [Figure 3] Figures 3A to 3H are diagrams showing exemplary embodiments of a distal protection device that can be used in the present system. [Figure 4] A diagram showing the force applied to the collection part.

Best Mode for Carrying Out the Invention

[0027] The present invention relates to a system that can be used to retrieve occlusions from a living blood vessel. The present invention is particularly useful for retrieving emboli from cerebral blood vessels.

[0028] The principles and operations of the present invention will be better understood by reference to the drawings and the accompanying description.

[0029] Before describing at least one embodiment of the present invention in detail, it should be understood that the use of the present invention is not limited to the details described in the following description. The present invention is capable of other embodiments or of being practiced or carried out in various ways. It should also be understood that the terminology and phraseology used herein are for the purpose of description only and should not be regarded as limiting.

[0030] In order to effectively remove an occlusion from an artery, it is necessary to effectively penetrate, engage / fix, release from the blood vessel, and not release particles into the blood flow, and minimize the stimulation / damage to the blood vessel wall.

[0031] US9987027 by the present inventor discloses a catheter that is effective in penetrating, engaging, releasing, and retrieving thrombus substances while minimizing damage to the blood vessel wall.

[0032] In experimenting with some prototype devices, the present inventor noticed that while the catheter design is very effective in releasing and collecting embolic substances from an occluded artery, in some cases, when pulled back into a larger blood vessel (e.g., the carotid artery), the inward radial force acting on the device decreases due to the increase in blood vessel diameter, and the engagement between the embolic substance and the retrieval device may be impaired.

[0033] The orientation of the retrieval device's lamellae facilitates penetration of the occluding thrombus, and when retracted posteriorly, resistance from the thrombus causes the lamellae to open, resulting in the scooping up of thrombotic material.

[0034] Once the thrombus is retrieved, the catheter is pulled back to the collection section (funnel), which is designed to contact the blood vessel wall at its distal opening, allowing the lamellae and thrombus to be drawn to the center and collected in the funnel without fragmentation or loss of the thrombus.

[0035] The distal capture device ensures that any fragments of thrombus that may form are captured and collected in the funnel when the distal capture device is retracted posteriorly.

[0036] Accordingly, according to one aspect of the present invention, a system and kit are provided for removing (removing and optionally recovering) an obstruction in a biological blood vessel. As used herein, the term “biological blood vessel” refers to any blood vessel capable of supporting the flow of biological material. The blood vessel may be a natural blood vessel or a synthetic blood vessel implanted in the body. Examples of blood vessels include blood vessels such as veins and arteries, lymphatic vessels, urinary tract blood vessels such as the urethra and ureters, the vas deferens, salivary ducts, and bile ducts. An obstruction is any blockage (embolism) that restricts the flow within a blood vessel, caused by the local accumulation of material, and examples include atherosclerotic embolus, migraines, biological stones, and foreign bodies.

[0037] This system comprises three components that function together to collect and retrieve embolic material from the body's blood vessels. These components include a retrieval device that has an elongator and multiple leaf-like extensions arranged around the distal portion of the elongator to deliver them to the body's blood vessels.

[0038] When extending from the delivery tube, the leaf-like extensions unfold outward and are positioned at a posterior (proximal) angle relative to the extension body. As the extensions advance through the occluding material and are retracted proximally, their leaf-like (inwardly concave) shape scoops up the occluding material.

[0039] The retrieval device can be configured as a catheter for use with a guidewire (GW) to remove material from a blood vessel. When configured as a catheter, the extension can include a longitudinal lumen sized to accept the guidewire (e.g., 0.014 inch, 0.018 inch, or 0.035 inch, or other guidewires). The lumen can be configured for use in an over-the-wire or rapid-exchange manner.

[0040] The extension of the retrieval device is 10–200 cm in length and 0.05–50 mm in width / diameter in a closed configuration (suitable for delivery within a 0.1–30 F sheath). The extension is preferably axial (rod or tube) in shape and can be manufactured from any biocompatible material, including alloys such as stainless steel and nitinol, or polymers such as polyimide (PI) and polyether block amide (PEBA) Pebax. The extension is preferably axially rigid to facilitate lodging of the distal portion (which carries the extension), but at the same time, it is flexible enough to easily pass through winding blood vessels (e.g., blood vessels in the brain) while ensuring safety. The rigidity of the extension (catheter) is in the same range as catheters commonly used to navigate biological blood vessels such as blood vessels.

[0041] The extension extends radially outward, preferably at an angle of 0 to 60 degrees toward the proximal end of the extension. The extension can be any shape (a combination of several shapes, including rectangles, triangles, ellipses, polygons, spirals, or simple or complex shapes with fractal properties) and any profile (circular, ellipses, rectangles). The extension can be connected directly to the extension device body or via a connecting element (e.g., a stem).

[0042] The axial stiffness of the stem portion of the extension can preferably be 0.1 to 100 grams (e.g., 10 to 90, 20 to 80, 30 to 70, 40 to 60) or more, depending on the location, type, size of the closure, the structure of the extension, and the material of the stem. The axial stiffness of the extension can also be 0.0 to 50 grams (e.g., 5 to 40, 10 to 30, 20 to 25) or more, depending on the location, type, size, and structure and material of the extension.

[0043] The extension and optionally the stem are preferably elastically deformable and are manufactured from elastomer materials such as thermoplastic elastomer (TPE), silicone, other plastics, or metal alloys such as nitinol. The elasticity is selected so that when the device is advanced distally to an occlusion (thrombus) in a biological blood vessel, the force exerted by the occlusion / thrombus mass causes the extension to fold relative to the extension. This allows the extension to remain within the thrombus mass without extending beyond the occlusion (e.g., thrombus) or extending distally. When the device is pulled proximal, the resistance force exerted by the occlusion (thrombus) mass causes the extension to extend outward (to an angle set by the stem or the vessel wall limit), allowing the device to engage / lock with the occluding material, release it from the vessel wall, and remove it.

[0044] Typical dimensions of the extended portion are 0.2 to 30 mm in length, 0.05 to 20 mm in width, and 0.03 to 3 mm in thickness, with a surface area of ​​0.01 to 600 mm² on one side.

[0045] The stem portion can have a length of 0.1 to 20 mm, a width of 0.02 to 20 mm, and a thickness of 0.03 to 3 mm.

[0046] Depending on the biological blood vessel, the size and type of occlusion, and the function of the device, any number of extensions can be mounted on the extension body. A typical number of extensions can be 1 to 20 or more. The extensions can be mounted in pairs, triplets, etc., on a fixed joint or a rotary joint.

[0047] The inner surface of the extension (the surface facing the extension) is preferably concave to increase the surface area and the resistance applied to the inner surface by the thrombus. Such a concave configuration also improves the extension's ability to collect (scoop up) occluding material. The outer surface of the extension is preferably convex to facilitate intravascular delivery and to remain in the occlusion folded in a "closed configuration" (arrow-shaped) when it enters the occlusion due to the resistance applied to the extension by the occluding material. While such configurations are preferred, it has also been considered that the inner and outer surfaces may have different contours (e.g., both sides flat).

[0048] Each extension can also be folded in half lengthwise to further improve penetration into the occluding material. Such folding can occur in response to the mechanical forces applied to the extension by the occluding material and the blood vessel wall during use.

[0049] The distal portion (tip) of the extension is preferably curved inward to minimize trauma / damage to the blood vessel as the device moves within the vessel. To further reduce trauma and irritation to the vessel wall, the tip can be manufactured from a very soft material (softer than other parts of the foliate structure).

[0050] The inwardly curved tip also makes it easier to hook the extended portion onto the obstructing material.

[0051] The inner surface (and optionally the outer surface) of the extension may have surface-mounted protrusions arranged as an array of a specific size and distribution, thereby allowing the protrusions to engage with the repeating structure of the occlusion surface.

[0052] In the case of a thrombus, this repeating structure is a component of the fibrin network of the thrombus.

[0053] This system / kit has a funnel-shaped collection section (when deployed) that has the function of collecting the recovery device and the obstructing material together. The funnel section is positioned inside the outer tube and deploys (radially outward) when it extends from the outer tube (or when the tube is pulled backward to remove the cover). The funnel section has a distal opening for receiving the recovery device and the obstructing material. The distal opening can be closed by a traction wire or other mechanism known in the art.

[0054] The funnel section is fitted into an inner tube having a lumen for receiving the extension and the distal extension of the retrieval device. Such a lumen can also carry a traction wire used for optional closure of the distal opening.

[0055] The funnel section can be manufactured from cut tubing or wire mesh (nitinol or stainless steel (round or flat wire)), with dimensions ranging from 10 to 100 mm in length and 1 to 50 mm in diameter. The diameter range for round wire is 0.01 to 0.5 mm, and the thickness for flat wire is 0.01 to 0.5 mm, with a braiding density of 50 to 110 PPI (Picks Per Inch). The funnel section can be coated / covered with polymer materials such as polyurethane, PTFE, or silicone.

[0056] A vacuum source (e.g., pump, syringe) can be connected to the system and used to apply suction to the internal volume of the coated funnel section to assist in the collection of thrombus by the thrombus retrieval device.

[0057] When isolated within the outer tube, the funnel takes on a tubular shape limited by the size and shape of the lumen of the outer tube. The funnel is deployed by extending it out of the outer tube using an inner tube attached to the proximal end of the funnel. Once deployed, the funnel forms a funnel shape with a distal opening whose size is limited by the diameter of the lumen of the biological blood vessel.

[0058] This system / kit also includes a distal capture device, which serves as an additional safety measure to ensure complete thrombus retrieval. The retrieval and capture devices are positioned distal to the thrombus. The capture device acts as a barrier against fragmented or released material. The distal capture device can be delivered through the lumen of the elongator (e.g., 0.017 inches) or another dedicated lumen of the elongator and has a trap attached to a wire / rod for advancing the collection unit through the GW lumen.

[0059] When deployed, the trap of the distal capture device takes on any shape, including but not limited to pigtail, spherical, floral, parachute, net-like, spiral, or other shapes suitable for capturing embolic fragments.

[0060] The distal capture device can be fully retracted into the funnel or the distal opening of the funnel can be capped.

[0061] This system / kit can be used as follows: The outer tube, containing the collection unit and retrieval device, can be moved along the wire to navigate to a site near the occlusion. The retrieval device can then advance from the collection unit and enter and pass through the occlusion. The guidewire is then removed, and the distal capture device is advanced through the guidewire lumen and positioned at the distal site of the occlusion. The collection unit can then be deployed, and the retrieval device can be pulled proximally to collect the occluding material, with the capture device positioned to capture the upstream fragment. The retrieval device and distal capture device can then be pulled proximally into the collection unit, and the distal capture device can be pulled proximally to cover the distal opening of the collection unit. The entire system can then be retracted into the outer tube and taken out of the body.

[0062] The distal tip of the foliate projection can be curved inward to facilitate centering the retrieval device in the collection section. Centralization can also be achieved by adding an olive-shaped or foliate structure (a structure oriented in the opposite direction to the distal foliate structure) to the proximal end to center the proximal portion when the proximal portion of the device is retracted. The proximal foliate structure may include projections (leaves) designed to invert when retracted into the collection section. Friction between the projections and the inner surface of the collection section can be reduced by using a coating on the mesh funnel section, small mesh holes (0.01-0.5 mm wide), and various mesh wire profiles.

[0063] Because this device can be used in both large and small vessels, the collection section is designed to maintain a relatively low radial outward force while fully or partially deployed in the relatively small (distal) vascular system, allowing for full radial deployment in the larger proximal vascular system. This differs from stent retrievers, which require high radial forces.

[0064] Such functionality can be achieved by configuring the geometric shape of the collection section's braid to apply relatively low radial force in small vessels (e.g., inner diameter ID of 0.5–3.0 mm) and provide full deployment in larger vessel sizes (e.g., inner diameter ID of 3.0–7.0 mm).

[0065] Because the radial force applied by the collection unit is relatively low compared to a stent retriever, its function is limited to filling the vascular space while applying minimal force to the inner wall of the vessel, whether it is a small vessel partially open or a large vessel fully open.

[0066] In contrast to stent retrievers made by laser cutting, which are manufactured from metal tubing and thus apply radial force along the entire length of the device, braided devices can be configured with multiple parameters to control the radial force applied to the vessel wall. For example, the characteristics of the wire (flat or round, thickness, material type), the number of wires, and the braid configuration can be selected to apply a variable force along the length of the device.

[0067] The collection unit is designed to allow thrombus fragments to enter the capture device and to capture these fragments while applying minimal radial force to the blood vessel.

[0068] To this end, the braided structure has a relatively large "window" (opening) (<4 mm) on the proximal side to capture thrombus fragments, and a relatively small window (<1.5 mm) on the distal side to capture and hold thrombus fragments. The braid is formed as two cones connected at the base, forming a rhomboid cross-section. This design enables two main functions. (a) Minimize direct contact with blood vessels (only at the central maximum diameter). This minimizes the radial force applied to the blood vessel wall when the collection unit is retracted. (b) The geometric shape reduces the force applied to the vessel wall when the collection unit is pulled back. As shown in Figure 4, the force applied to the collection unit by the thrombus captured therein (B) and the blood flow are opposite to the force applied by the physician (A), and these opposing forces generate an inward radial force (c) that reduces friction between the collection unit and the vessel wall.

[0069] Referring here to the drawings, Figures 1A–3H show the system of the present invention, which is referred to herein as System 10. System 10 (assembled in Figure 1A) can be provided as a kit including some or all of the components shown in Figures 1B–1F.

[0070] System 10 includes an outer tube 12 (sheath) for housing the collection unit 14, the retrieval device 16, and the distal capture device 18 (for example, in a coaxial layout). System 10 is deliverable and deployable on the wire 20, as will be further described below.

[0071] When used for embolization in cerebral blood vessels, the outer tube 12 can have a length of 90 cm, an outer diameter of 8 F (0.105 inches) mm, and an inner diameter (diameter of the lumen 22) of 6.7 F (0.088 inches). The outer tube 12 can be manufactured from polymer using well-known methods.

[0072] The lumen 22 of the outer tube 12 can be used to deliver the collection section 14, which includes a funnel section 24 attached to the tube 26. The length of the funnel section when folded can be 10 to 30 mm, the diameter 0.017 to 0.027 inches, and the diameter of the distal end 28 when expanded can be 2 to 6 mm. The funnel section 24 can be manufactured from a 0.055 to 0.075 mm wire (nitinol or a combination of nitinol and other metals), braided at an angle of 105 to 135 degrees, and the braided wire has a cell size of 0.3 to 0.8 mm. The funnel section 24 can self-expand when it extends from the outer tube 12, or it can be manually expanded using a known method (e.g., a traction wire). The opening 30 of the distal end 28 is limited to the inner diameter of the blood vessel. The tube 26 is 100–125 cm long, with an outer diameter of 0.75–0.85 inches and an inner diameter of 0.58–0.72 inches (diameter of the lumen 32). The lumen 32 can be used to deliver a wire 20 (e.g., GW) or a distal capture device 18.

[0073] The retrieval device 16 includes a tube 17 with a plurality of extensions 19 attached to its distal portion 21. The tube 17 has a length of 150-160 cm, an outer diameter of 0.028-0.034 inches, and an inner diameter of 0.017-0.021 inches (diameter of the lumen 27 ("27" is not shown)).

[0074] Each extension 19 may include a leaf-shaped body 23 (3-6 mm in length, with a 1-3 mm wide inwardly concave middle section) and an inwardly curved end 25. The extensions 19 may be arranged in opposing pairs offset around the distal portion 21 (forming a spiral) or in other suitable configurations. The lumen 27 can be used to deliver the GW 20 or the capture device 18.

[0075] The distal capture device 18 may include a wire / rod 40 attached to the trap 42. As shown in Figures 3A–3H, the trap 42 can be any of several trap 42 designs, including but not limited to loops (Figure 3A), balls / nests (Figures 3B, 3E), flowers (Figures 3C, 3F), cones (Figure 3D), spirals (Figure 3G), and parachutes (Figure 3H). The trap 42 may include a soft tip 43 at its distal end.

[0076] The trap 42 has the function of capturing embolic fragments generated by the retrieval of occluding material. The trap 42 can be designed to self-deploy when it advances out of the tube 17 through the lumen (17). To this end, the trap 42 can be manufactured from one or more wires braided into a shape suitable for use as a trap. The trap 42 may also include an impermeable marker 44 ("44" is not shown in the drawing (Figure 3F)) for precise positioning relative to the retrieval device 16 and / or occlusion.

[0077] As described herein, this system / kit can be used to recover occlusive material from any blood vessel.

[0078] Figures 2A–2E show the use of system 10 in the middle cerebral artery.

[0079] The femoral or radial artery is punctured using the Seldinger technique, the carotid artery is catheterized, and a long sheath is advanced into the internal carotid artery on the side of the occlusion. System 10 is advanced coaxially with the guidewire 20 (Figure 2A), the collection unit 14 is advanced to the distal end of the sheath, and the retrieval device 16 is further advanced into the occluded thrombus (Figure 2B). The guidewire 20 is replaced with a distal capture device 18 that is advanced through the microcatheter of the retrieval device 16 and deployed distal to the occlusion (Figure 2C).

[0080] The collection unit 14 is deployed through the carotid artery sheath 12, and the retrieval device 16 and capture device 18 are retracted into the collection unit 14. Suction is optionally applied through the collection unit 14 and the sheath 12. Alternatively, a balloon-guided catheter (guide catheter with proximal balloon) can be used for retrieval instead of the sheath 12.

[0081] The collection unit 14, the retrieval device 16, and the capture device 18 (containing the captured embolic material) are retracted into the sheath 12 of the balloon guide catheter and removed from the patient's body.

[0082] The term "approximately" used here refers to a range of ±10%.

[0083] For clarity, it is understood that certain features of the present invention described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, although various forms of the present invention have been described in the description of one embodiment for the sake of brevity, they may also be applied separately or as appropriate subcombinations.

[0084] Although the present invention has been described in relation to its specific embodiments, it is obvious that many alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, it is intended to encompass all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

[0085] All publications, patents, and patent applications described herein are incorporated herein by reference in their entirety, as if explicitly and individually noted, when each individual publication, patent, or patent application is indicated to be incorporated herein by reference. Furthermore, any citation or identification of any reference in this application should not be construed as an acknowledgment that such reference is available as prior art of the present invention. Where section headings are used, they should not necessarily be construed as restrictive. Furthermore, any one of the priority documents of this application is incorporated herein by reference in its entirety.

Claims

1. A system for embolus retrieval, (a) A thrombus recovery device having multiple foliate extensions, (b) A collection unit configured to transition between a folded state when isolated within an outer tube and an expanded state when extended from the outer tube, The thrombus recovery device is capable of taking in the collection unit when the collection unit is in an expanded state. system.

2. The collection unit transitions to a funnel shape when it extends from the outer tube. The system according to claim 1.

3. The aforementioned multiple leaf-like extensions are attached to the distal portion of the elongated body. The system according to claim 1.

4. The aforementioned plurality of leaf-like extensions unfold radially outward when they extend from the outer tube. The system according to claim 1.

5. The extended portion folds relative to the extended body when it extends distally, and unfolds radially outward when the extended body is retracted proximal. The system according to claim 4.

6. The leaf-like extension is concave. The system according to claim 1.

7. The aforementioned leaf-like extension includes a distal tip that curves inward. The system according to claim 1.

8. The collection unit is formed from a wire mesh or a laser-cut or etched foil. The system according to claim 1.

9. The collection unit is coated with a polymer material such as polyurethane, PTFE, or silicone. The system according to claim 8.

10. Further equipped with a distal capture device, The system according to claim 3.

11. The distal capture device is attached to the distal end of the thrombus recovery device or is deliverable via the thrombus recovery device. The system according to claim 10.

12. The distal capture device can be delivered via the guide wire lumen of the extension. The system according to claim 11.

13. The distal capture device, when extended, takes the shape of an umbrella, parachute, flower, spiral, or ball. The system according to claim 10.

14. The extended body is deliverable via the collection unit. The system according to claim 3.

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