Dual channel thrombectomy device

Abstract

The invention is entitled "Dual Channel Thrombectomy Device". A device for removing a clot from a blood vessel can have a dual layer with an inner inflatable member extending within an outer inflatable member. The inner inflatable member can be divided into one or more segments with a proximal segment having a clot pinching structure configured to pinch a clot between the pinching structure and the outer catheter. A distal flow passage segment of the inner member can be configured to form a flow passage through the clot to restore blood flow to the downstream vasculature. Struts of the outer inflatable member can form closed cells that are not fully circumferential in a proximal portion to allow the clot to pass inside the pinching structure and engage the pinching structure, and are fully circumferential in a distal portion to support the blood vessel for clot dissection. A protective element at a distal end of the device can prevent escape of clot debris.

Description

Technical Field

[0001] This disclosure relates throughout to apparatus and methods for removing acute blockages from blood vessels during endovascular medical treatment. More specifically, this disclosure relates to a clot retrieval device for removing clots from blood vessels. Background Technology

[0002] This disclosure relates to apparatus and methods for removing acute obstructions from blood vessels. Acute obstructions may include clots, misaligned devices, migrating devices, large emboli, etc. Thromboembolism occurs when a thrombus partially or completely detaches from the vessel wall. This clot (now called an embolism) then travels in the direction of blood flow. If the clot remains in the cerebral vascular system, it can cause ischemic stroke. If the clot originates in the venous system or the right side of the heart and remains in the pulmonary artery or its branches, it can cause pulmonary embolism. Clots may also not be released as emboli, but rather form locally and obstruct blood vessels; this mechanism is more common in the formation of coronary artery occlusions. The apparatus and methods described herein are particularly suitable for removing clots from cerebral arteries in patients with acute ischemic stroke (AIS), from pulmonary arteries in patients with pulmonary embolism (PE), from coronary arteries or graft vessels in patients with myocardial infarction (MI), and from other peripheral arteries and veins in which clots cause occlusion.

[0003] Numerous access challenges exist that can make device delivery to the target site difficult. In cases involving navigation of the aortic arch (such as in coronary artery or cerebral occlusion), the arch configuration in some patients makes positioning the guiding catheter challenging. The tortuousness challenge is even more pronounced in arteries near the brain. For example, at the distal end of the internal carotid artery, it is not uncommon for the device to have to navigate rapidly and continuously through several extremely tortuous segments of the vessel over a journey of only a few centimeters. In cases of pulmonary embolism, access can be obtained via the venous system and then through the right atrium and ventricle of the heart. The right ventricular outflow tract and pulmonary artery are fragile vessels that are easily damaged by inflexible or high-specification devices. For these reasons, it is desirable for clot retrieval devices to be as compatible as possible with thin and flexible access and support catheters.

[0004] The vascular system in the area where clots may become lodged is typically fragile and delicate. For example, neurovascular systems are more delicate than vessels of similar size in other parts of the body and are located in a bed of soft tissue. Excessive tension applied to these vessels can lead to perforation and bleeding. Pulmonary vessels are larger than those in the brain's vascular system, but they are also delicate, especially the more distal vessels.

[0005] Stent-supported clot retrieval devices are increasingly used to remove clots from cerebral blood vessels in patients with acute stroke. These devices typically rely on pinning mechanisms to capture the clot by trapping it between a self-expanding stent-like body and the vessel wall. This approach has several drawbacks.

[0006] Stent-type clot retrieval devices rely on their outward radial force to maintain their grip on the clot. This compressive force tends to dehydrate the clot, which in turn increases its coefficient of friction, making it more difficult to detach and remove from the vessel. If the radial force is too low, the stent-type clot retrieval device will lose its grip on the clot, while if the radial force is too high, the stent-type clot retrieval device may damage the vessel wall and require excessive force to withdraw. Therefore, stent-type clot retrieval devices with sufficient radial force to handle all clot types may result in vascular trauma and serious patient injury, while stent-type clot retrieval devices with appropriate radial force to remain non-invasive may not be effective in handling all clot types in thrombectomy cases. Pinning the clot between the stent-type clot retrieval device and the vessel wall also results in high shear forces against the sides of the clot when it is removed, potentially releasing clot fragments. If these fragments are not held by the device, they may be released, leading to further obstruction in the distal vascular system.

[0007] Because the way its strut elements are connected to each other causes the struts to be under tension during retraction, some conventional stent-type clot retrieval devices are not well designed to maintain their expanded shape when placed under tension in a vascular bend. This tension is caused by friction between the device and the vessel, and it increases if additional loads are applied (such as resistance provided by the clot). This can lead to loss of clot gripping as the stent-type clot retrieval device retracts proximally near the bend in a tortuous vessel, where the captured clot may escape. At the bend, the strut located on the outside of the bend is under higher tension than the strut on the inside. To obtain the lowest possible energy state, the outer surface of the clot retrieval device moves toward the inner surface of the bend, which reduces the tension in the struts but also reduces the expansion diameter of the device.

[0008] Furthermore, when attempting to remove long clots, conventional devices shorter than the clot are unlikely to restore flow through the occluded area upon deployment. Therefore, the pressure gradient across the clot remains a significant obstacle to its removal. Simply manufacturing such devices as longer ones could make them difficult to trace through tortuous anatomy and could traumatize the vascular system, requiring more force to withdraw and potentially jamming the device column, necessitating surgical removal.

[0009] In pursuit of surgical efficiency, devices with multiple bodies have also been used. Such devices may have an outer body capable of supporting the target vessel and an inner body for embedding and capturing clots. These devices engage well with and separate clots, but a larger and generally stiffer network of struts can potentially make it more difficult to retract the device and partially or completely re-insert the clot into the external catheter. Compression of the components of the outer body during this process may hinder or even loosen the inner body's grip on the captured clot, especially for longer clots or in cases where a grip is maintained between the device and the distal end of the external catheter through clamping action. The larger expansion shape of the outer body during partial or complete collapse of the device during retraction can cause the outer body struts to impact or deflect those of the inner body.

[0010] The effectiveness of the given device is also important because, for many reasons, physicians often need to make multiple passes to completely remove the embolism. Each time the clot retrieval device is withdrawn, the pathway to the target site is lost. Therefore, it may be necessary to reinstate the guidewire and microcatheter to approach and re-pass through the clot, and then remove the guidewire and allow the clot retrieval device to be advanced through the microcatheter. Navigating the guidewire and microcatheter to the clot can take a considerable amount of time, especially if the vessel is tortuous. The additional time and device manipulation increase the risk of complications to the patient, highlighting the importance of an effective and efficient device.

[0011] Any device needs to overcome the aforementioned challenges to deliver a high level of success in clot removal, restoration of blood flow, and promotion of good patient outcomes. The present invention is designed to provide an improved clot retrieval device that addresses these deficiencies. Summary of the Invention

[0012] This design pertains to a clot retrieval device for removing clots from a body's blood vessels. The device may have a strut frame forming an elongated internal body having a proximal end, a distal end, and a longitudinal axis. The elongated internal body may be divided into one or more segments extending distally from the proximal axis used to manipulate the device. The proximal segment may have a clot clamping structure that has a collapsed delivery configuration when constrained within an external catheter, an expanded clot engagement configuration when deployed at a target site, and a clot clamping configuration in which the clamping structure is at least partially constrained. When the device transitions from the engagement deployment configuration, the clot clamping structure may be configured to clamp and hold the clot when in the clot clamping configuration.

[0013] The clot clamping structure can take various forms, such as a flat pattern arranged in an undulating or spiral manner. In one example, the clamping structure comprises an array of adjacent segments. These segments can be segments with a low strut density, abutted by a high-density ring, or vary in shape at different longitudinal locations such that the radial forces exerted by at least two adjacent segments within the clot are different from each other. In another example, the clamping structure may have a series of clot receiving holes. These holes may consist of one or more flexible struts extending between the coronal portions, such that when the struts are compressed, these holes can shrink portions of the clot within the holes. These patterns allow a microcatheter or external catheter to be advanced over the proximal end of the clamping structure to compress and hold the clot located between the catheter tip and at least a portion of the struts of the clamping structure as the device transitions from an inflatable deployment configuration to a partially constrained clot clamping configuration.

[0014] The more distal segment of the device's elongated internal body can be a porous internal channel, which can be securely connected to the distal end of the clot clamping structure. The internal channel may include a tubular body composed of multiple struts defining closed orifices around a longitudinal axis. These orifices and struts can be designed to penetrate the clot and apply radial force to form a lumen through the clot, and to restore flow to a radially expanded configuration upon deployment. These orifices can also allow portions of the clot to escape compression by displacing through the orifice openings, thereby reducing the radial force applied to the vessel wall, minimizing vascular trauma, and reducing tensile disturbance to the distal vascular bed.

[0015] The device may have dual expandable members, whereby the characteristics of the inner and outer members can be customized independently of each other. In one example, an outer retainer with an inner elongated body is provided. The outer retainer may be coaxial with or radially offset from the inner elongated body. The outer retainer may expand to a greater extent than the inner elongated body and is configured to be juxtaposed with and support the target vessel wall. The inner elongated body may be substantially disposed within the lumen of the outer retainer. The radial expansion difference between the inner body and the outer retainer defines a receiving space between them in which the clot can be received.

[0016] Similar to the internal elongated members, the external retainer may also have one or more segments. The retainer may have a proximal first support segment with a strut frame, thereby forming one or more longitudinally arranged proximal expandable bodies. The proximal expandable bodies may be made of non-circumferential closed apertures forming one or more support arms spaced apart around a longitudinal axis, such that a large circumferential gap exists between adjacent arms. For example, the first support segment of the external retainer may have two support arms that are diametrically opposed and spaced 180 degrees apart.

[0017] The external retainer may also have a distal second stent segment with a strut frame forming one or more longitudinally arranged distal expandable bodies. Similar to the first stent segment, the second stent segment may have a network of obturators around a longitudinal axis. The perforations in the distal expandable bodies of the second stent segment may be fully circumferential to support the vessel at all clock positions. A distal segment of an elongated internal body and porous internal channels may be disposed within the lumen of the second stent segment.

[0018] The occlusion apertures of the first and second stent segments of the external retainer may be larger than the apertures of the internal body. Therefore, the external retainer can be configured to expand within the occluded clot in the blood vessel, allowing the clot to migrate into its receiving space when the retainer expands.

[0019] To increase device flexibility, the expandable bodies of the first and second stent segments can be hinged to each other, allowing them to flex independently as the device advances or retracts through bends in the vascular system. Additionally, the orifice of each expandable body of the first and second stent segments may have a strut forming at least one distal vertex, which is not connected to an adjacent closed orifice.

[0020] In another example, the clot retrieval device may have a two-layer configuration, wherein an inner elongated body is disposed within a porous outer body. The inner elongated body may have a proximal clot engagement element having a constrained delivery configuration, an expanded clot engagement deployment configuration, and at least a partially constrained clot clamping configuration. The distal side of the clot engagement element may be a tubular internal channel having the constrained delivery configuration and the expanded deployment configuration. Upon expansion, the tubular internal channel may utilize radial forces to restore blood flow in the occluded vessel.

[0021] The clot bonding element may have a strut frame configured to exert an outward radial force on the clot when it expands to the deployment configuration. The amplitude of the outward force may vary along the length of the clot bonding element. In one case, the radial force follows a generally sinusoidal waveform pattern. The amplitude of the waveform pattern may be approximately equal at the peaks, or it may differ at the proximal or distal ends to obtain a stronger grip on the clot portion. For example, the amplitude of the peaks may decrease along the length of the clot bonding element, making them higher at the proximal end and lower at the distal end.

[0022] The device may also have a longitudinal axis extending centrally through the proximal clot-binding element and the distal tubular internal channel. The struts of the clot-binding element may be flat or planar, such that when deployed to the expanded state, the pattern is aligned with or around the axis. In one example, the struts of the element may be formed in a planar pattern twisted around the axis in a spiral or helical shape. In a separate example, the struts may form multiple adjacent segments with high strut density regions and low strut density regions or longitudinally asymmetrical regions, such that the radial forces applied by two adjacent segments are different from each other to maintain better clot gripping. In additional cases, adjacent struts of the clot-binding element may be bent or twisted in the same or different directions to change the radial force, such that when the clot-binding element moves to the clot clamping configuration, the captured clot is compressed and clamped.

[0023] In a two-layer device configuration, the outer body surrounding the inner elongated body can be a porous outer body having a non-circumferential proximal segment and a fully circumferential distal segment connected to the proximal segment. The outer body can be designed such that, when deployed from the delivery catheter, it expands to a greater radial extent than the radial expansion of the inner elongated body. When folded inside the catheter, the radial dimension of the outer body can be equal to or greater than the radial dimension of the inner body.

[0024] The proximal and distal segments of the porous external body may each have one or more expandable bodies. Each expandable body may have multiple struts forming an obturator. These holes are typically larger than, for example, the holes of the elongated internal body, allowing the expandable external body to apply radial forces to the clot and target vessel while providing a scaffold that will not impede the passage of the clot and its capture by the internal body. Each expandable body of the proximal and distal segments may have struts joined together at at least one distal apex, which is not connected to another adjacent obturator, thereby enhancing flexibility by allowing each body to flex independently and respond to local forces. Other portions of the expandable body may have converging regions where the struts intersect with intermediate connecting struts or connecting arms that engage adjacent bodies.

[0025] The risk of embolism during clot retrieval using this device can be reduced by providing a distal fragment protection element attached to one or both of the internal elongated member or the external retainer. The protection element may consist of a mesh or stent area spanning the lumen of the vessel toward the distal end of the device. The element can be three-dimensional due to its depth and surface area. In some cases, fibers or filaments are used to provide an added stent within the element with minimal impact on the device profile or deliverability. A stent combining a fragment protection element with both the internal and external members provides a more effective filter than using a single member alone.

[0026] In one example, the distal portion of the internal elongated body may have multiple struts configured as fragment protection elements in a volumetric pattern around the longitudinal axis. The distal portion of the internal elongated body may also have a bulging or expanding strut frame.

[0027] In alternative examples, the fragment protection element may be attached to or be part of the distal portion of the external retainer or component. The end of the external retainer may also taper through a series of distal crown supports. The crown supports of the external component may be constructed in a generally conical shape, such that the external component acts as a natural barrier surrounding the protection element, necking distally. The supports may also be circumferentially crossed to occupy a larger cross-sectional area, or have strands in the mesh or braid to increase coverage.

[0028] A method for removing an occlusive clot from a blood vessel using a clot retrieval device may include the step of providing an external catheter having a tubular body and a bushing located at a distal end of the external catheter. A clot retrieval device may also be provided having an elongated shaft that mates with an expandable element capable of transitioning from a collapsed delivery configuration to an expanded deployment configuration. The clot retrieval device may have an inner body having a proximal clot clamping element connected to a more distal flow channel element. An outer body may be arranged around the inner body, wherein a non-circumferential first stent segment engages with a fully circumferential second stent segment. The second stent segment may have a pivoting or hinged connection to the first stent segment to allow the device to adapt to sharp bends in the vascular system.

[0029] This method may involve delivering a clot retrieval device in a collapsed configuration to a target occlusion, such as when the clot retrieval device is folded or restrained within a microcatheter. The microcatheter can be guided to the target site using a guidewire or other techniques generally known in the art via a guide catheter or intermediate catheter. The microcatheter can be advanced through the clot and then withdrawn to expose the clot retrieval device and allow it to expand within the clot. A gap in the non-circumferential first stent segment allows at least a portion of the clot to be exposed to the internal clot clamping element. Similarly, the radial force from the expansion of the fully circumferential second stent segment can partially displace the clot through a large external orifice, allowing the clot to engage with a flow channel element. Expansion of the flow channel element can open a path to at least partially restore blood flow, thereby enabling vascular recanalization.

[0030] To continue the method for removing the clot, the clot retrieval device is held firmly in position as the external catheter is advanced along its slender axis, such that the liner of the external catheter engages with the expandable element to clamp at least a portion of the clot in a compression manner between the liner and the clamping element. Once the user feels resistance indicating that the clot has been clamped and is being held, the external catheter, along with the clot retrieval device and the captured clot, can be withdrawn from the blood vessel while maintaining relative positioning so that the liner remains engaged with the expandable element of the clot retrieval device. The clot retrieval device and the clamped clot can then be completely removed from the patient.

[0031] In many cases, after some or all of the occluded clot has been retrieved, contrast agent can be injected via an external catheter to allow for a more comprehensive assessment of vascular patency. If emboli remain in the vessel, additional clearance can be achieved using a thrombectomy device. Any remaining device can then be removed from the patient once adequate recanalization of the target vessel is observed. The device disclosed herein provides a means of minimizing the number of catheter advances required to treat a patient, thereby reducing the likelihood of vascular injury and associated vascular anatomical risks when multiple passes are necessary.

[0032] Other aspects and features of this disclosure will become apparent to those skilled in the art after viewing the following detailed description in conjunction with the accompanying drawings. Attached Figure Description

[0033] The foregoing and other aspects of the invention will be further discussed with reference to the following description and the accompanying drawings, wherein similar reference numerals indicate functionally similar or identical elements. The drawings are not necessarily drawn to scale; rather, the emphasis is on illustrating the principles of the invention. The drawings depict one or more specific embodiments of the device of the invention by way of example only and not by way of limitation.

[0034] Figure 1 An isometric view of a clot retrieval device according to various aspects of the present invention;

[0035] Figure 2 Another view of a clot retrieval device according to various aspects of the present invention is shown;

[0036] Figure 3 The invention illustrates aspects thereof. Figure 2 The external retainer of the clot retrieval device;

[0037] Figure 4 The invention illustrates aspects thereof. Figure 2 Another view of the external holder of the clot retrieval device;

[0038] Figure 5 The invention illustrates aspects thereof. Figure 2The slender internal body of the clot retrieval device;

[0039] Figure 6 An enlarged view of the strut structure of the block clamping structure of the elongated internal body according to various aspects of the present invention;

[0040] Figure 7 An alternative elongated internal body of the clot retrieval device according to various aspects of the present invention is shown;

[0041] Figure 8 A view of another alternative elongated internal body of the clot retrieval device according to various aspects of the present invention;

[0042] Figure 9 Another alternative elongated internal body of the clot retrieval device according to various aspects of the invention is shown;

[0043] Figure 10 An exemplary graph of the radial force applied along the block clamping structure by the axial position according to various aspects of the present invention;

[0044] Figures 11a to 11c are a series of views illustrating the use of a clot retrieval device at a target location according to various aspects of the present invention;

[0045] Figure 11d continues the series of Figures 11a to 11c, illustrating the interaction between the external conduit and the clamping structure in the clot clamping configuration according to various aspects of the invention;

[0046] Figure 11e continues the series of Figures 11a to 11c, showing the withdrawal of a clot from the blood vessel when clamped in a clot-clamping configuration according to various aspects of the invention; and

[0047] Figures 12 to 13 A flowchart outlining the method of using the system according to various aspects of the present invention. Detailed Implementation

[0048] The purpose of the design disclosed in this invention is to create a clot retrieval device that can more effectively and efficiently remove emboli from the vascular system while maintaining a high level of deliverability and flexibility during surgery. The design may have an external expandable member within which an internal expandable member extends. The devices disclosed in this invention share a common theme of a two-layer configuration, wherein the internal member has clot clamping and trapping capabilities and the external member provides minimal interference with these capabilities. Both members may be directly or indirectly connected to an elongated shaft, and a distal mesh or support constructed at the distal end of the device prevents clot fragments from escaping. This distal mesh may be attached to the shaft, the internal or external members, or multiple of them.

[0049] This double-layered construction is designed to allow lumps to enter through large openings or gaps in the outer expandable member and reside in a receiving space positioned between the two expandable members. At least a portion of the inner member may have a denser support than the outer member, thereby preventing lumps from entering its lumen and thus creating flow channels on the lumps once the device is deployed.

[0050] Both the internal and external expandable components are advantageously made of a material that can automatically recover its shape once released from a high-strain delivery configuration. This material can take many forms, such as wires, strips, sheets, or tubes. A suitable manufacturing process could be laser-cutting of the nitinol tubes, followed by heat setting and electropolishing of the resulting structure to form the strut frame and connecting elements. As described herein, a range of designs are envisioned for each of these elements, and any of these elements can be combined with any other element; however, to avoid repetition, they are not shown in any possible combinations.

[0051] Specific examples of the invention will now be described in detail with reference to the accompanying drawings. While this specification is in the context of mechanical thrombectomy in many cases, these designs are also applicable to other surgical procedures and other bodily pathways.

[0052] Accessing various blood vessels within the vascular system to achieve clot formation (whether coronary, pulmonary, or cerebral) involves well-known surgical procedures and the use of many routinely available commercially available accessory products. These products, such as angiography materials, rotary valves, delivery catheters, and guidewires, are widely used in laboratory and medical procedures. Their function and exact construction are not described in detail when used in conjunction with the disclosure of the present invention as described below.

[0053] See Figure 1 The clot retrieval device 100 may have an elongated shaft 6 and an expandable structure constructed at the distal end of the elongated shaft 6, the expandable structure having internal and external components. These components may be an external retainer 210 and an elongated internal body 110 to capture clots and facilitate the restoration of blood flow through the clot after the clot retrieval device 100 has been deployed at the target site. The external retainer 210 may be a stent structure with large orifices through which the clot can pass and enter a receiving space 9 defined by an annular region between the elongated internal body 110 and the external retainer. A fragmentation protection element 14 may be positioned near the tapered end 218 of the external retainer 210 near the distal end 4 of the device 100. The external retainer 210 and the elongated internal body 110 may have a collapsed configuration for delivery within the microcatheter and an expandable configuration for clot retrieval, flow restoration, and fragmentation protection.

[0054] The internal and external components are preferably made of hyperelastic or pseudoelastic materials, such as nitinol or another such alloy with high recoverable strain. Shaft 6 may be a tapered spool and may be made of stainless steel, MP35N, nitinol, or other materials with suitable high modulus and tensile strength. Shaft 6 and device 100 may have indicator strips or markings to indicate to the user during insertion when the distal end of the device approaches the end of the microcatheter, or to mark the end of the device during surgery. These indicator strips may be formed by printing, removing, or masking areas of the shaft used for coating, or by using radiopaque elements visible under fluoroscopy, so that they are visually distinguishable from the rest of the shaft.

[0055] Shaft 6 may be coated with a material or have a polymer sheath to reduce friction and thrombosis. The coating or sheath may consist of a polymer, a low-friction lubricant such as silicone, or a hydrophilic / hydrophobic coating. The coating may also be applied to the outer cage 210 and the elongated inner body 110.

[0056] The dual-layer multi-diameter device 100 shown throughout the various figures of this disclosure has several advantages. The inner body 110, with a smaller radial dimension, can be securely embedded in the target clot to hold it firmly at a steep opening angle, while the outer retainer 210, with a larger radial dimension, can remain in contact with and juxtaposed to the vessel wall and prevent the clot from migrating distally as the device retracts proximally into the vessel with a gradually increasing diameter.

[0057] Figure 2 It shows Figure 1 A top view of a composite device 100 having dual internal and external expandable members. Both the inner body 110 and the outer retainer 210 can be integral structures, with the outer retainer configured to substantially enclose the inner body. The aperture of the outer retainer 210 serves as an inlet for the clot and allows the outer retainer to apply force to the clot in a direction substantially parallel to the direction of the clot being pulled out of the blood vessel (i.e., substantially parallel to the longitudinal axis 8) upon retraction. This means that the outward radial force applied to the vascular system can be kept to a minimum. By configuring the outer retainer 210 to facilitate the clot's movement across the receiving space 9, the device can more effectively detach the clot from the vessel wall. The outer retainer 210 may also have a closed distal end 218 defining a surface configured to serve as a clot fragment blocking surface together with the fragment protection element 14.

[0058] The elongated internal body may have multiple regions to provide both strong gripping and strong opening force for the clot, thereby forming a lumen to restore flow upon deployment. The elongated internal body 110 may have a proximal clot clamping segment 120 that provides strong gripping of the clot for the critical initial step of detaching the clot from the blood vessel, allowing the external retainer 210 to be constructed with low radial force.

[0059] The distal segment of the elongated internal body 110 may be a porous internal channel 130 configured to form a flow lumen through at least a portion of the clot. This flow lumen reduces the pressure gradient across the clot, thereby facilitating its separation and removal. The porous internal channel 130 may be tubular in shape and have a customizable diameter upon expansion to reduce the risk of reperfusion injury. This constrained blood flow through the lumen ensures that the pressure applied to the vessel is below normal immediately after flow is restored, thereby reducing the risk of bleeding in the vascular bed. Full perfusion can then be restored by removing the device and the trapped clot.

[0060] The external retaining structure 210 may be a plurality of struts forming an expandable body configured to expand to a diameter greater than the radial dimension of the internal body 110 upon release from the restraint sheath (such as a microcatheter). Figure 3 As shown. A proximal expandable body 216 may be disposed around the clot-holding or clamping segment 120 of the inner body 110, and a distal expandable body 217 may be disposed around the porous internal channel 130. Proximal, the outer retainer 210 may have a support arm 222 that engages with the shaft 6 at the proximal joint 212 and expands radially to form the proximal expandable body 216. The support arm 222 may have a tapered profile as shown to ensure a gradual transition in rigidity from the shaft 6 to the clot-jointing expandable body. The support arm 222 may be oriented to form a closed-cell network at discrete locations around the longitudinal axis 8 of the device 100, such that there is a large circumferential gap between adjacent arms. For example, as shown, two sets of arms 222 may be largely diametrically opposed to each other at approximately 180 degrees, or three sets of arms may be spaced 120 degrees apart.

[0061] The proximal portion of the external retainer 210 may have an expandable body 216 with an aperture that is not fully circumferential around the device, thus providing a support level lower than that of the distal expandable body 217. A portion of the clot may pass through the gap between the aperture and the support arm 222 of the proximal expandable body 216, such that they are engaged by the clot clamping structure 120. The not fully circumferential aperture in the proximal expandable body 216 results in a lower surface contact area and radial force, which allows the clot to more easily protrude into the gap within that segment of the device. When the device is retracted into the external conduit, the clot clamping structure 120 maintains a firm grip on the clot without interfering with impacts from the support of the arm 222 of the external retainer 210. The support arm 222 may also have bends or crowns that will move away from or at least not offset in the same direction as the clot clamping element, such that the support arm does not shear a portion of the clot when the proximal portion of the device is partially restrained by the external conduit.

[0062] One or more proximal expandable bodies 216 can be connected to the nearest body of the distal expandable body 217 via connecting struts 233. In one example, these connecting struts 233 can be generally straight struts extending parallel to the central longitudinal axis 8 of the device. In other examples, these connecting struts 233 can have multiple struts constructed in one or more holes, or can include curved or helical arms. An inlet 214 can be formed in the region between adjacent expandable bodies 216, 217, through which a lump or portion of a lump can pass and enter the receiving space 9 between the elongated inner body 110 and the outer retainer 210.

[0063] The distal portion of the outer retainer 210 may have a tapered end 218 that slides radially downward in a substantially tapered profile to the distal engagement 213. The taper and convergence of the struts at the tapered end 218 reduces the aperture of the opening between the struts to form a debris trapping area. These struts may be distal coronal struts 237 connected to the distal inflatable body 217 via connecting struts 234, such as… Figure 3 As shown. The distal coronal portion 237 may protrude and bulge or expand, so that the end of the external retainer 210 is non-invasive to the blood vessel using it. The struts forming the bulge or expansion may not be parallel to those of adjacent portions of the external retainer, thus forming a joint or hinge through which the tapered end 218 can be bent or flexed around the distal expandable body 217. The junction 213 may be a twisted or coiled assembly of fibrous struts, which may have or be endowed with radiopaque properties to mark the end of the device 100 during surgery.

[0064] The distal expandable body 217 can then be connected via one or more connecting arms 234, which can extend from the proximal joint 239 to the distal joint 240, such as... Figure 4 Seen in a side view of the external retainer 210. Connecting arms 234 may be generally straight and extend parallel to the longitudinal axis 8 of the device 100. In other cases, these connecting arms may be multiple struts constructed in one or more holes, or may have a curved or helical profile. The area between the distal expandable bodies 217 may define an inlet 214 through which the clump can pass and enter the receiving space 9. The connecting arms 234 between the distal expandable members 217 may be substantially aligned with the connecting struts 233 between the proximal expandable body 216 and the distal expandable body 217 to align with the neutral axis of the body during bending.

[0065] The proximal expandable body 216 and distal expandable body 217 of the external retainer 210 may have a series of interconnected struts to form closed orifices, wherein some struts, such as coronal struts 232, terminate at a coronal or distal vertex 236, wherein no distal connecting element is connected to any adjacent closed orifice, and other body struts, such as 242, terminate at a body joint 244. The distal vertex 236 may be offset from the longitudinal axis 8 of the device 100 and may be close to the cylindrical plane defined by the external retainer 210 during expansion. The coronal struts 232 engaged at the distal vertex 236 may be substantially bent to maximize the offset and spacing between vertices, thereby achieving a desired balance between the clot support and device flexibility. Allowing the free vertices 236 to lack distal connections at some joints provides greater bending flexibility to the device. This is because, in addition to the bending of the struts forming each orifice, the vertices themselves can be bent to accommodate bending in the vascular system and have some ability to respond to clot forces.

[0066] When the microcatheter retracts during device deployment, the outer retainer 210 expands and contacts the vessel wall. This contact provides stability to the device 100 and minimizes torsion when any helical portions of the inner elongated body 110 and clamping segment 120 disengage within the vessel. This facilitates uniform deployment and expansion of the device 100 within the embolus or clot.

[0067] The expansion of the external retainer 210 can cause compression and / or displacement of the clot during expansion, depending on the level of support provided by the strut. When the expandable body provides a high level of support, the clot can be compressed. Alternatively, when the expandable body provides an escape path or opening, the expandable body will push the clot toward the opening. The clot itself can have many degrees of freedom and can move in many different directions. By providing an external retainer 210 with a length substantially the same as or longer than the length of the occluded clot, many of the clot's available degrees of freedom of movement are removed. An inlet opening 214 is provided in the external retainer 210 to guide the main degrees of freedom of movement available to the clot, so that the expansion of the external retainer pushes the clot into the receiving space 9. This allows the clot to be retrieved without excessive compression. This is advantageous because compression of the clot can lead to its dehydration, which in turn increases the clot's frictional properties and stiffness, making it more difficult to detach and remove from the vessel. If the clot can easily migrate inward through the holes or gaps in the proximal portion of the external retainer as it expands outward toward the vessel wall, this compression can be avoided.

[0068] Another advantage of using a self-expanding body is that, due to the volumetric properties and stiffness of the target clot, resistance during deployment across the clot can cause device 100 to initially expand only to a portion of its free expansion diameter. This gives the outer retainer 210 the ability to expand further to a larger diameter while retracting, allowing it to remain in contact with the vessel wall as it retracts into the progressively larger and more proximal vessel.

[0069] Figure 5 Showing from Figure 2 The device 100 has an internal elongated body 110. The bulk-jointed clamping segment 120 and the porous internal channel 130 can be integrally formed from a single strip or tube of a shape memory material such as nitinol, and then laser-cut to form a strut pattern. Alternatively, they can be formed independently and subsequently attached to allow the two components to have different shapes. The internal body 110 may also have a proximal joint or transition section between the proximal end 121 of the clamping portion 120 and the elongated shaft 6 on which the device is mounted.

[0070] The elongated inner body 110 can be configured to expand to a diameter smaller than that of the smallest vessel it is intended to be used in. When the inner body is non-conical, this diameter is typically less than 50% of the diameter of the expanded outer retainer, and in some cases can be as low as 20% or less of the outer retainer diameter. This allows portions of the inner body to be constructed from very small volumes of material, as it only needs to expand to a fraction of the diameter of the outer retainer, and is therefore highly flexible in both collapsed and expanded states. This flexibility advantageously allows the inner body to be displaced in one direction by a portion of the clot and in another direction by another portion of the clot.

[0071] The clot clamping segment 120 can be an engaging element in the proximal region of the inner elongated body 110 of the device 100. The clamping segment 120 is designed to facilitate clot removal by expanding between the clot and the vessel wall to engage with the clot over a significant surface area and with minimal clot compression. Overall clot compression is minimized because the segment can be configured with a high-compression ring and a deep strut embedding, with areas of minimal clot compression and low radial force distributed throughout. A portion of the clot may protrude into the low-compression area and be clamped between the catheter tip and the device strut. Clamping is achieved by advancing a microcatheter or external catheter forward over the proximal end 121 of the clamping segment 120 until a portion of the clot is compressed between the catheter tip and the coronal or strut of the clamping segment. This clamping facilitates clot removal because it increases the device's grip on the clot (specifically, fibrin-rich clots). The clamping also reduces detachment force by elongating the clot during the detachment process by separating it from the vessel wall. During the retraction of the clot into the microcatheter or external catheter, clot retention can be improved by controlling the proximal end of the clot and preventing the clot from obstructing lateral branch vessels.

[0072] Distal to the clot clamping segment 120, the internal channel 130 may be generally tubular, planar, or some other shape, wherein the diameter of the lumen structure is smaller than the diameter of the peripheral portion of the external retainer 210. In one example, the distal internal channel 130 may be transformed from the distal end 122 of the clot clamping segment to form a cylindrical shape, such that the radial dimension of this segment is smaller than or larger than the radial dimension of the proximal clamping segment 120 in the illustrated expansion configuration. This allows for the formation of a flow channel across a very long clot without over-compressing the clot or causing the internal channel 130 to engage with the vessel wall. The internal channel 130 may be formed integrally with the clamping segment or may be formed separately and connected via a bushing or other mechanical connector. In other cases, the internal channel 130 may have a non-cylindrical cross-section, its diameter may be non-uniform, and it may have a custom strut pattern to provide areas with different radial forces or flexibility.

[0073] In another example, the shape could be essentially tubular and have, for example, a... Figure 5 The plurality of struts shown are spaced apart from and converge toward the axis 8 of the device. The struts form holes 132 that are configured to engage the clot in their expanded state and define a flow lumen through the clot. When expanded, the holes 132 can interpenetrate the clot and provide additional gripping to facilitate initial clot separation, while also supporting the flow lumen through the clot to prevent fragment release.

[0074] The distal end 136 of the internal channel 130 can be converted into a debris protection structure 14 or connected to it via a tether or shaft. The debris protection structure 14 can be a plurality of struts constructed in a volumetric pattern, woven or tangled mesh filter, or basket or conical shape to prevent or collect debris traveling distally from the device. Structure 14 can also be a spherical or similarly shaped bundle of fibers, and in its expanded state, at least a portion of the debris protection structure has a radial dimension larger than that of the flow channel 130 and the clamping segment 120, and can be dimensionally similar to the diameter of the target blood vessel. The distal end of the debris protection element 14 can have a radiation-impermeable coil element 16, which can be laser-cut from the same tubing used in the construction of the internal channel 130 during processing.

[0075] The internal elongated body 110 and the external retainer 210 can engage proximally at axis 6 and distally during assembly to minimize tension between components during use. The struts of the clot clamping segment 120, the internal channel 130, or both can be extended and shortened such that the length of the internal body and the external retainer are substantially the same when loaded into a microcatheter and when freely expanding at the target site. The closed-hole design along the internal body and external retainer of the coil element 16 allows the device to accommodate small length differences through stretching without imposing significant tensile or compressive forces on the connector. Length differences can occur, for example, when the device expands, collapses, or is deployed in a small blood vessel.

[0076] Figure 6 It shows Figure 5 Enlarged and magnified views of the clot clamping segment 120 of the internal elongated body 110. Alternative segment 145 may be formed by overlapping struts, forming an intermediate crown 147 at a local apex. Segments of low-density grooves 146 may extend between and be defined by consecutive segments 145, wherein longitudinally extending bridging struts apply a lower level of support and reduced radial force compared to those generated by the segments 145. The overlapping of the struts allows each segment 145 to twist relative to its adjacent ring when the clamping portion 120 expands or contracts, but each twist cancels out the next, resulting in minimal overall twist in the clamping portion at the distal end 122 relative to the proximal end 121. This minimal twist helps ensure that the grip on the clamped clot is not lost.

[0077] The longitudinal length of the bridging struts in the low-density grooves 146 between the rings of the struts 145 can vary. For example, when used in the middle cerebral artery, the longitudinal spacing can be approximately 3 mm to 6 mm. This spacing allows the clot to protrude between the struts, where the clot engages with a clamping segment in an expanded deployment configuration. The total length and / or number of the ring segments 145 and the groove segments 146 can be optimized for the desired length and density for optimal embedding in the clot. The bridging struts 144 between the ring segments 145 can be straight and parallel to the axis 8 of the device for better pushability, thus ensuring that the device can be delivered through tortuous anatomical structures.

[0078] The struts in the clamping segment 120 may also have one or more bends 148 at various axial locations along their length. The "dog-leg" shape formed by these bends 148 in the struts 144 may be repeated around the segment in the circumferential or radial direction to form holes. The angle formed by the bends 148 or the length of the struts 144 may vary in appropriate locations, or different struts in the pattern may have different widths, allowing for higher expansion forces in various segments to improve adhesion to the aggregate in the expanded deployment configuration. This structure can be prepared by laser-cutting nitinol raw material and heat-setting it to achieve the desired profile during expansion.

[0079] Figure 7 Another example of an elongated internal body 110 is shown, having a distal internal channel 130 and a proximal engaging element configured as a clot-jointing clamping segment 120. When fully expanded, the clamping segment 120 may have the same or different radial dimensions as the internal channel 130, but the two structures may be integrally formed such that there is no significant stiffness transition at the distal end 122 of the clamping segment. A fragment protection element 14 may be formed or otherwise attached to the distal end 136 of the internal channel 130 and is configured to change to a size greater than the expanded radial dimensions of both the clot clamping segment 120 and the internal channel when the device 100 is deployed across the clot.

[0080] and Figure 5 Compared to the previous configuration, the clamping segment 120 may have more densely spaced segments 145 along its length. As discussed, the segment 120 may have strut rings 145 and regions 146 with low radial force and strut density. When advancing the microcatheter or external catheter, having adjacent segments 145 closely spaced together at certain axial locations of the clamping segment 120 can increase the clamping effect between the rings in the clot clamping configuration.

[0081] During retraction, clamping of fibrin-rich clots may be lost, or the clot may contain erythrocyte-rich "soft" segments that are not fully grasped on the proximal clamping segment 120. In these cases, the strut of the distal porous internal channel 130 can provide engagement with the clot and retrieve the clot back to the microcatheter or external catheter through the enlarged diameter vessel, through bends and branches. Furthermore, the expanded orifice and / or strut of the fragment protection element 14 engages with any released fragments or ungrasped clot segments with minimal shear.

[0082] See Figure 8 Another internal elongated body 110 is shown, which has some structural features similar to the other devices described above. The internal elongated body 110 can be attached proximally to the shaft 6. This connection can be a bushing or some other axial constraint that allows at least partial relative rotation between the outer retainer 210 and the internal body. During surgery, a radiopaque marker (not shown) can also be used at this location to mark the proximal termination point of the expandable portion of the device 100.

[0083] The internal body 110 may have a proximal clumping element 120 and a more distal tubular internal channel 130. A three-dimensional mesh-like structure or basket may be formed from threads or fibers as a debris protection element 14, which is held at the distal end 136 of the distal internal channel 130 and within the external retainer 210. The threads or fibers may be randomly coiled and / or twisted to occupy space within the structure, or they may be shaped into a specific pattern.

[0084] The clumping bonding element 120 may have struts forming a plurality of adjacent segments 152, wherein the different shapes of the adjacent segments result in unequal radial forces generated by consecutive adjacent segments. Some struts may have bends 148 (such as... Figure 6 (As shown), this configuration allows adjacent struts 144 to compress the clot when the clot-attaching element transitions from an expanded deployment configuration to a partially constrained clot-clamping configuration. The struts in portions of adjacent segments 152 may overlap at an angle to the longitudinal axis 8 of the device, thus allowing them to slide relative to each other in different directions when positioned in or moving through bends in the vascular system. Additionally, portions of adjacent segments 152 may have the characteristic of collapsing along certain planes or varying their length in the axial or radial directions. This difference in strut length ensures variation in the radial force applied to the clot by the clamping segment 120, achieving good clot gripping while facilitating clot retrieval associated with the microcatheter or external catheter.

[0085] exist Figure 9In another example of the illustrated device 100, the strut pattern of the clumping clamping segment 120 of the internal elongated member 110 can be formed by laser-cutting a generally flat two-dimensional sheet and wrapping the resulting flat pattern around a cylindrical mandrel before heat setting. The centerline of the device can then be formed into a spiral or coiled pattern around the longitudinal axis 8, similar to the process of wrapping a strip around a cylinder. At the proximal end, the clumping clamping structure 120 can be connected to the shaft 6. The internal channel 130 connected at the distal end 122 of the clumping clamping segment 120 can also be a flat pattern with a curved or irregular cross-section, or a generally tubular shape as shown in other disclosed examples.

[0086] When deployed across the clot, portions of the clot can migrate through the inlets 214 and holes of the expandable bodies 216, 217 of the outer retainer 210, or the space between the expandable bodies, and into the receiving space 9 or the device. Here, the clot can protrude into areas of low strut density and also into the central lumen of the spiral pattern of the clot clamping structure 120. The gaps and lower supports of the proximal expandable body 216 facilitate entry into the spiral of the clot clamping structure 120. As the device 100 subsequently retracts, and as the outer conduit advances distally to change the device from an expanded deployment configuration to a partially constrained clot clamping configuration, the spiral improves gripping and separation performance and facilitates the clot clamping action. Such effects can be increased if the clot clamping structure 120 of the device 100 is constructed of two or more spiral coiling components.

[0087] The spiral shape also allows portions of the clot clamping structure 120 to elongate under tension, thereby stretching portions of the clot during dissection. The proximal end of the clot can be clamped and restrained on the clot clamping structure 120, while the distal end of the clot can be positioned on the internal channel 130 to embed and open a flow channel. If the distal end of the clot remains adhered to the vessel, the internal channel 130 and the external retainer 210 can remain stationary, while the clot clamping segment 120 expands in some segments and contracts in other segments in response to clot forces. This action helps to peel the clot from the vessel wall during the procedure and reduces dissection forces.

[0088] Fragment protection element 14 can be connected to the distal end 136 of the internal channel 130 via a tether or shaft 134. Protection element 14 can be a volumetric pattern that expands to a radial dimension larger than the radial dimension at any point along the elongated internal body 110. The element can be shaped like a conical basket, a mesh element, or a bundle of fibers, occupying sufficient space to prevent clots or thrombus fragments from passing distally.

[0089] When the components are in an expanded deployment configuration and a clinker clamping configuration, the exact shape and configuration of the strut network and adjacent segments 152 of the clinker clamping element 120 will determine the radial force applied at different axial locations along the structure. The force can vary, for example, in a generally sinusoidal waveform pattern 124, where locally varying peaks 126 determine the force amplitude 128 at that location. A sample curve of the radial force varying along the axial position of the clinker clamping element 120 is shown in... Figure 10 The diagram illustrates this concept. The amplitude 128 can be repeated at patterned distances such that it is relatively equal along the length of the engaging element 120, or it can decrease along its length such that the force is lower at the distal end 122 and higher at the proximal end 121, where the initial gripping of the clamp allows the clot to disengage. The graph shows how, for example, a segment 145 embedded in the clot can have a higher radial force than the low-density grooved segments 146 between the rings. The effectiveness of the radial force increase region can be increased by maximizing the angle of the strut relative to the longitudinal axis of the vessel, which allows the segment 145 to grip the clot rather than slip over it. These regions with different radial forces allow the device 100 to maintain gripping of the clot in the region of peak 126 while applying much less compression to the clot between peaks, which helps to minimize the total force required to retract the clot.

[0090] When advancing the microcatheter or external catheter to increase clamping of the clot, the user can feel the clamping resistance and stop advancing the catheter, or alternatively, advance a fixed distance above the proximal end 121 of the engagement element 120 and the more proximal expandable body 216 of the external retainer 210. The lower level of the support in the proximal expandable body 216 of the external retainer 210 allows the relative tension between the engagement element 120 and the catheter to be maintained, so that the clamping between the engagement element and the catheter does not deteriorate during clot retraction.

[0091] Figures 11a to 11e and Figure 12 and Figure 13The flowchart illustrates the method of use of the design disclosed in this invention. A guidewire 11 and a microcatheter 13 are inserted and guided through the vascular system 40 and advanced through the occlusive clot 20 using conventionally known techniques. When the microcatheter 13 is positioned distal to the occlusive clot 40, the guidewire 11 can be removed from the vessel 40 to allow the clot retrieval device 100 to be advanced through the microcatheter. The device 100 is advanced in a collapsed configuration until the distal end of the device reaches the distal end of the microcatheter. The microcatheter 13 can be retracted while the device 100 is held in position using the shaft 6 to deploy the clot retrieval device onto the clot 20, preferably in such a manner that the distal end of the device is positioned distal to the clot, as shown in FIG11b. The device 100 expands such that the external retainer 210 can engage with the occlusive clot 20 and allow the clot to pass radially inward. The clot clamping segment 120 and the porous internal channel 130 can expand to embed into the clot and provide flow channels to restore blood flow in a controlled manner. Once the controlled flow has been stabilized through the internal channel 130, the device 100 may be allowed to remain within the clot 20 for a period of time if necessary.

[0092] Figure 11c shows the clot 20 engaged with the device during retrieval of the microcatheter 13. Advancement of the catheter causes the liner 12 to compress the clot 20 between the coronal 147 of segment 145 and the bridging strut 144 of the low-density groove segment 146, as shown in Figure 11d. Depending on the conditions, clamping engagement may also be affected by an intermediate catheter or other external catheter. The clot may be partially located in the device's inlet opening 214 and also partially located in the receiving space 9 defined by the area between the inner body 110 and the outer retainer 210. Clot fragments may be captured in the distal closed conical end 218 of the outer retainer 210 and the fragment protection element 14 to prevent fragment release into the bloodstream. Flow occlusion, aspiration, and other standard techniques may be used during this procedure.

[0093] The relative tension between the device and the microcatheter can be maintained by the user during dissociation and retraction to ensure that the clamping of the clot is maintained, as shown in Figure 11e. While the use of a microcatheter or intermediate catheter to clamp the clot is described as providing additional beneficial effects when used with the present invention, all embodiments described herein can also be used to dissociate and retrieve the clot without the use of catheter clamping (if desired). The distal closed end of the external retainer 210 of the device 100 and the expanded fragment protection element 14 prevent the release of trapped clot fragments into the bloodstream.

[0094] Figure 12 and Figure 13This diagram illustrates the steps of a method for performing a thrombectomy using such a device. The steps can be implemented using any of the exemplary devices or by suitable alternatives described herein and known to those skilled in the art. The method may have some or all of the steps described, and in many cases, the steps may be performed in a different order than that disclosed below.

[0095] See Figure 12 The method 1200 outlined herein, step 1210 may involve providing an external catheter, which may have a tubular body and a liner at its distal end. Depending on the circumstances, the external catheter may be a microcatheter, an intermediate catheter, or any other suitable sheath known to those skilled in the art, with a diameter adapted to achieve clamping of the device, as previously described.

[0096] Step 1220 provides a clot retrieval device having a collapsed delivery configuration, an expanded deployment configuration, and an expandable element. A proximal axis can be used to manipulate the device during surgery. The expandable element may have an inner body and an outer body, the outer body being expandable to a greater radial extent than the inner body. The inner body may have a proximal clamping element and a distal flow channel element. The outer body may have a non-circumferential first support segment disposed around the clamping element and a fully circumferential second support segment surrounding the flow channel element and connected distal to the first support segment. The non-circumferential first support segment allows portions near the clot to easily pass inward through a gap in the outer body to engage with the proximal clamping element of the inner body.

[0097] Step 1230 may involve delivering a clot retrieval device in a collapsed delivery configuration to the occluded vessel via a microcatheter. In cases of intracranial occlusion, multiple access routes are possible, including direct insertion into the carotid artery, brachial artery approach, or femoral artery approach. Once access to the arterial system is established using conventional and well-known techniques, a guide catheter or long sheath (not shown as part of Figures 11a-11e) is typically placed as close as possible to the occluded clot. For example, in the case of middle cerebral artery occlusion, the guide catheter may be placed in the internal carotid artery proximal to the carotid siphon. The microcatheter may then be advanced through the clot with or without a guidewire. Once the tip of the microcatheter has been advanced through the clot and to the distal end of the clot, the guidewire (if used) may be removed, and the clot retrieval device is advanced through the microcatheter until it reaches the distal end.

[0098] Then, in step 1240, the microcatheter can retract, allowing the clot retrieval device to expand within either side of the clot. This step may also involve the expansion of the stent region of the outer body within the clot to apply compressive forces, thereby pushing the clot through the inlet orifice and into the space between the inner and outer bodies. When the outer body is deployed into the expanded deployment configuration, at least a portion of the clot can radially pass through the circumferential gap in the non-circumferential first stent segment and contact at least a portion of the clamping element. Due to the larger orifice opening in the outer body and the gap in the non-circumferential first stent segment, clot compression can be controlled and minimized. Minimizing compression on the clot reduces the forces applied radially outward to the vessel wall, which in turn reduces the frictional forces to be overcome when retracting the clot.

[0099] See also Figure 13 Method 1300 may include step 1310, which inhibits clot migration into the flow channel element to allow blood flow through the flow channel element in an expanded deployment configuration. Because the device can be configured with a two-part long internal body, the expansion of the flow channel element during device deployment creates a flow channel through the clot, thereby restoring flow to the distal vascular bed and reducing the pressure gradient across the clot. This reduction in pressure gradient decreases the force required to detach the clot from the vessel wall and retract it proximally. Additionally, the flow channel allows the device to remain safely in place and remain in position for a period of time before withdrawal. This dwell time allows the distal vascular bed to be gently perfused with fresh, oxygenated blood, rather than being exposed to sudden transient spikes in pressure and flow, as in cases where the clot is immediately removed or the device compresses the clot so much that a very large flow channel is formed during deployment.

[0100] While firmly maintaining the position of the clot retrieval device, step 1320 may involve advancing an external conduit along an elongated axis such that the bushing of the external conduit engages with an expandable element to clamp at least a portion of the clot in a compressed form using a clamping element. This can be accomplished by suction via the external conduit and / or guide conduit to help maintain a firm grip on the clot and prevent fragment loss. However, the design disclosed in this invention, which firmly grips the clot and securely houses it within the receiving space, has the additional beneficial effects of a distal fragment protection element and a support area. The protection element may be spaced apart from the distal end of the internal member, thus being optimally positioned to capture any fragments released from the clot during retraction.

[0101] In step 1330, the external catheter and clot retrieval device are withdrawn from the blood vessel in a coordinated manner, while maintaining engagement between the external catheter liner and the expandable element. This engagement, along with aspiration, maintains a firm grip on the clot as it is withdrawn through bends and along successive larger vessel diameters.

[0102] In step 1340, the clot retrieval device and the clamped clot can be removed from the patient. If necessary, the device can be rinsed and gently cleaned in saline and then reloaded into the microcatheter. It can then be reintroduced into the vascular system for redeployment to additional occluded clot segments, or if further access is required for complete recanalization.

[0103] The invention is not necessarily limited to the described examples, the configurations and details of which may vary. The terms “distal” and “proximal” are used throughout the foregoing description and refer to position and orientation relative to the treating physician. Similarly, “distal” or “towards distal” refers to a position away from the physician or in a direction away from the physician. Likewise, “proximal” or “towards proximal” refers to a position close to the physician or in a direction toward the physician. Furthermore, unless the context clearly indicates otherwise, the singular forms “an,” “a,” and “the / described” include plural references.

[0104] As used herein, the term “about” or “approximately” for any numerical value or range indicates a suitable dimensional tolerance that allows a collection of parts or components to achieve the intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of values ​​±20% of the listed values; for example, “about 90%” may refer to a range of values ​​from 71% to 99%.

[0105] In describing the example embodiments, terminology is used for clarity. Without departing from the scope and spirit of the invention, each term is intended to be contemplated for its broadest meaning as understood by one skilled in the art, and includes all technical equivalents that operate in a similar manner to achieve a similar purpose. It should also be understood that reference to one or more steps of the method does not preclude the presence of additional method steps or intermediate method steps between those explicitly identified steps. Similarly, some steps of the method may be performed in a different order than that described herein without departing from the scope of the disclosed technology. For clarity and brevity, not all possible combinations are listed, and such variations are generally obvious to one skilled in the art and are intended to fall within the scope of the following claims.

Claims

1. An apparatus for removing clots from a blood vessel, comprising: A strut frame forming an elongated internal body, the elongated internal body having a proximal end, a distal end, and a longitudinal axis, the elongated internal body comprising: A clot clamping structure comprising a constrained delivery configuration, an expanded clot engagement deployment configuration, and at least partially constrained clot clamping configuration, the clot clamping structure being configured to clamp the clot upon movement from the deployment configuration to the clot clamping configuration; and A porous internal channel, connected to the distal end of the clot clamping structure and comprising a tubular body configured to form a lumen through the clot and to restore flow upon deployment; and A strut frame forming an expandable tubular outer retainer, the outer retainer being capable of expanding to a greater extent than the radial direction of the elongated inner body to define a receiving space between the outer retainer and the elongated inner body, the outer retainer comprising: A first stent segment, comprising one or more proximal expandable bodies, each proximal expandable body including a plurality of non-circumferentially closed orifices forming one or more support arms spaced apart around the longitudinal axis, such that a large circumferential gap exists between adjacent arms, the clot clamping structure extending within the first stent segment; and The second stent segment includes one or more distally expandable bodies, the one or more distally expandable bodies including a plurality of fully circumferentially closed orifices located distal to the first stent segment, the porous internal channels extending within the second stent segment.

2. The apparatus of claim 1, wherein the struts of the porous internal channel define an internal body closed aperture, wherein the closed aperture of the first support segment and the second support segment of the external retainer is larger than the internal body closed aperture.

3. The apparatus of claim 1, wherein at least a portion of the porous internal channels is configured to interpenetrate the clumps when radially expanded into the deployment configuration.

4. The device of claim 1, wherein the first support segment comprises two support arms that are substantially diametrically opposed around the longitudinal axis.

5. The apparatus of claim 1, wherein each expandable body of the first support segment and the second support segment includes at least one distal vertex not connected to an adjacent closure.

6. The apparatus of claim 1, wherein the clot clamping structure comprises a plurality of adjacent segments, and wherein the plurality of adjacent segments are configured such that the radial forces applied by at least two adjacent segments are different from each other.

7. The apparatus according to claim 1, wherein the clot clamping structure comprises: A plurality of clot receiving holes, the plurality of clot receiving holes including a strut extending between the crowns, the strut being configured to clamp clots located in the clot receiving holes as the clot clamping structure moves from the expanded deployment configuration to the at least partially constrained clot clamping configuration.

8. The apparatus of claim 7, wherein the clot clamping configuration is achieved by advancing a conduit above the first support segment and the clot clamping structure until at least a portion of the clot is compressed between the end of the conduit and at least a portion of the strut of the clot clamping structure.

9. The apparatus of claim 1, wherein adjacent expandable bodies of the first support segment and the second support segment are hinged to each other.

10. A clot retrieval device for removing an occlusive clot from a blood vessel, comprising: An internal elongated body, the internal elongated body comprising: A proximal clot bonding element, the proximal clot bonding element comprising a constrained delivery configuration, an expanded clot bonding deployment configuration, and a at least partially constrained clot clamping configuration; and A distal tubular internal channel, connected to the distal end of the proximal clot-binding element and comprising a constrained delivery configuration and an expanded deployment configuration, the internal channel being configured to allow blood flow through the internal channel in the expanded deployment configuration; and A porous outer body comprising a non-circumferential proximal segment and a fully circumferential distal segment pivotally connected to the proximal segment, the outer body being capable of expanding to a greater extent than the radial extent of the inner elongated body; The proximal clot bonding element also includes a support frame configured to apply an outward radial force to the clot when expanded to the deployment configuration, the outward radial force varying along the length of the proximal clot bonding element in a generally sinusoidal waveform pattern. The non-circumferential proximal segment includes one or more proximal expandable bodies, each of which includes a plurality of non-circumferential closed holes. The non-circumferential closed holes form one or more support arms spaced apart around a longitudinal axis extending through the proximal clot bonding element and the tubular internal channel, such that a large circumferential gap exists between adjacent arms.

11. The apparatus of claim 10, wherein the amplitude of the waveform pattern is substantially equal along the length of the proximal clot bonding element.

12. The apparatus of claim 10, wherein the amplitude of the waveform pattern decreases along the length of the proximal clot bonding element, is higher at the proximal end of the proximal clot bonding element, and is lower at the distal end of the proximal clot bonding element.

13. The apparatus of claim 10, wherein the struts of the strut frame of the proximal clot bonding element are formed in a planar pattern arranged in a helical configuration around the longitudinal axis.

14. The apparatus of claim 10, wherein the proximal clot bonding element further comprises a plurality of adjacent segments, wherein the radial forces applied by at least two adjacent segments are different from each other.

15. The apparatus of claim 10, wherein the adjacent strut of the proximal clot engagement element includes at least one bend, the at least one bend being configured such that when the proximal clot engagement element moves into the clot clamping configuration, the adjacent strut compresses the clot.

16. The device of claim 10, wherein the distal segment of the outer body comprises one or more expandable bodies, the one or more expandable bodies comprising a plurality of support bars in a closed-hole configuration.

17. The apparatus of claim 16, wherein each of the one or more expandable bodies of the distal segment includes at least one distal vertex not connected to an adjacent closure.

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