Double-layer icad device

Abstract

The invention is entitled "Dual Layer ICAD Device". The invention provides a design that combines mechanical thrombectomy and stent implantation together to more effectively treat occlusive and stenotic lesions in the cerebral vasculature, the design features a dual layer of equipment. The outer layer consists of a deployable stent cage with large cell openings that can allow thrombus to pass through the openings into the inner layer of deployable capture segments. The clot capture segments can be configured to pinch and extract occlusions. The outer cage is configured to detach from the rest of the device and remain implanted as a stent to exert outward radial force to support and / or dilate a stenotic region. The device can have a distal debris protection element to prevent distal migration of elements released during the procedure.

Description

Technical Field

[0001] This invention relates generally to apparatus and methods for removing obstructions and treating cerebral vascular stenosis during endovascular medical treatment. More specifically, the invention relates to an apparatus that can be used as a standard clot retrieval device, while also having a removable element that can be retained implanted in the stenotic lesion if desired. Background Technology

[0002] Atherosclerosis is caused by lesions that narrow and reduce the space within the lumen of blood vessels in the vascular system. These lesions are typically composed of plaques, which can be fat, cholesterol, calcium, or other components of the blood. Severe occlusion or blockage can impede the flow of oxygenated blood to different organs and parts of the body, leading to other cardiovascular diseases such as heart attacks or strokes. Narrowing or stenosis of blood vessels can cause clots to form in situ and also increases the risk that clots and other emboli may become lodged in such locations, especially in neurovascular vessels that are already very small in diameter. Intracranial arteriosclerosis (ICAD) is the narrowing of arteries and vessels that supply blood to the brain and is a common approximation mechanism of ischemic stroke.

[0003] Treatment of vascular occlusion is well known in the art. Methods may include the use of drugs, such as anticoagulants or antiplatelet agents, and surgical procedures, such as surgical endarterectomy, angioplasty, and stent implantation. Recent successes in endovascular recanalization (ERT) have been driven by the further development of safe thrombectomy devices. Devices such as stent thrombectomy devices, direct aspiration systems, and other clot retrieval devices are strongly associated with better clinical outcomes. However, these devices are primarily designed to recanalize the vessel by removing and retrieving the occluded thrombus. If significant stenosis is also present at the site of occlusion, adequate recanalization may not occur, increasing the need for stent implantation.

[0004] Treatment methods for neurovascular conditions depend on several factors, including the degree of occlusion, the shape of the target occlusion site (i.e., the main trunk, branches, etc.), and the patient's overall condition. For these reasons, it may be unclear whether the occlusion is solely due to a blood clot or also involves stenosis. Identifying stenotic lesions during the treatment of stroke or transient ischemic attack can be challenging because it is difficult to distinguish them from clot- and other embolic occlusions via baseline angiography. This is especially true in the very small and tortuous vessels of the cerebral vascular system. In some cases, the stenotic lesion may not be identifiable before surgery. Therefore, physicians may need access to a variety of easily accessible treatment devices, including stent systems, that can be dynamically adapted based on diagnosis.

[0005] These challenges prolong the procedure, and in cases where both blood clots and stenosis are present, physicians often need to change catheters, devices, and guidewires after removing the clots. The need for multiple traversals and device deliveries during treatment increases the likelihood of ICAD lesions rupturing or releasing fragments. Such fragments can include, but are not limited to, blood clots, plaques, and other embolic debris. These fragments can lead to vascular occlusion, resulting in widespread stroke or death.

[0006] There is a persistent need to shorten the time from onset to surgery to reduce ongoing damage in ischemic stroke patients. Due to the difficulty in diagnosing ICAD, physicians may need to cross the lesion multiple times during treatment, further increasing the likelihood of rupture or further fragmentation and prolonging surgery. Therefore, systems and devices with improved performance remain needed to address endovascular occlusion, particularly ICAD lesions in neurovascular systems. Summary of the Invention

[0007] The aim of this design is to provide systems, devices, and methods that meet the aforementioned needs. The ability to perform mechanical thrombectomy and stent implantation using a single device or system such as the current design can significantly reduce procedure time, resulting in better clinical outcomes. This is especially true for stroke patients, where the degree of recovery is largely dependent on timing. Furthermore, in troublesome cases where the occlusion is thrombotic or atherosclerotic and clot retrieval is unsuccessful, the current design greatly improves surgical flexibility by allowing stent deployment immediately after capture attempts to maintain flow through the clot and support the lesion.

[0008] Generally, the system of this invention provides a dual-function device for addressing occlusions or blockages in blood vessels. The occlusion can be one or more of a clot, thrombus, lesion, or other embolism. The system can be deployed across the occlusion using a standard stent or thrombectomy device in a single microcatheter. The outer layer consists of a stent retainer with an open distal tip and a large unit opening that allows thrombi to pass through into the inner capture segment layer. The retainer can also use its radial force to expand the wall of the lesion for use as a temporary stent. The device can retract into the access catheter to retrieve aspirated thrombi from aspiration or access catheter. Multiple retrievals can be performed until satisfactory recanalization occurs. Once the blockage is cleared, the outer stent retainer can be removed from the patient or redeployed to the target and detached as a permanent stent implant.

[0009] Exemplary devices for removing obstructive occlusions from a patient's blood vessel and implanting a stent into the patient's blood vessel may include an internal capture segment capable of delivery from a microcatheter and an external stent retainer. Standard interventional techniques and commercially available assistive devices such as ingress catheters, balloon-guided catheters, and / or guidewires can be used to navigate the microcatheter to the target site in the neurovascular system. The capture segment is designed to retrieve obstructive clots or thrombi and may have an elongated body with a proximal end, a distal end, a collapsed delivery configuration, and a deployed configuration. The capture segment may include a strut frame or truss forming an external network of closure units. When the capture segment is deployed from the collapsed delivery configuration, at least a portion of this strut frame may be configured to engage the clot in a deployed state. In another configuration, the device may transition from a deployed deployment configuration to a partially restricted contracted configuration, wherein one or more portions of the occlusion may be compressed between the peaks of the strut frame of the capture segment when the device is pulled back into the external catheter. Aspiration applied during the procedure may facilitate removal of the clot from the vessel.

[0010] The stent retainer of the device may also have a collapse delivery configuration and a self-deployment configuration, and when in the self-deployment configuration, it can deploy to a greater radial extent than the capture segment. The retainer may include multiple interconnected struts formed as a network of large circumferential units. The units are large enough to provide minimal resistance to thrombi, clots, or other emboli migrating into the receiving space within the outer retainer. The stent retainer may also have one or more segments extending between its proximal and distal ends, wherein two or more of the struts are longitudinally aligned. In one example, the maximum radial dimension of the stent retainer when deployed may be approximately equal to the maximum radial dimension of the deployed capture segment. In one configuration, the struts of the stent retainer and the capture segment are longitudinally aligned, allowing thrombi to easily pass through the retainer and the capture segment. In some cases, the stent retainer may be two or more times the diameter of the capture segment. When the stent retainer is in the deployment configuration, its dimensions may also be set to have a maximum radial dimension greater than the maximum radial dimension of the target vessel, such that the stent retainer applies an outward radial force to the vessel during deployment to increase the local size of the lumen. This configuration allows the external retainer to provide expansion and support to the blood vessel as the captured segment and any released material are retrieved and withdrawn from the patient.

[0011] The stent retainer may be generally tubular in shape and configured to be at least partially eccentric to the capture segment. In one configuration, the stent retainer may have an open distal end with an open circumferential edge. The open edge may help restrain and retain the clot in which the device has been deployed. At its proximal end, the stent retainer may have a bushing or release point, wherein the retainer can be released from the remainder of the device and remain as a stent implant when the capture segment is removed. The capture segment of the device and the stent retainer may be delivered on a single actuable axis. In an alternative example, the retainer and the capture segment may be longitudinally movable independently of each other and may each have its own proximal axis for manipulating the retainer and capture segment within the patient's body.

[0012] Mechanical thrombectomy always carries the risk that fragments released during the procedure may migrate distally and become additional embolisms. Aspiration from one or more catheters is typically used to reverse the flow direction, but other protective measures may also be employed. In one aspect of current designs, a fragment protection element may be attached to a device tethered to and located distal to the capture section to act as a protective structure across the vessel lumen, thus occupying space and substantially preventing distal dislodgement of fragments. This element may be three-dimensional, having a depth and a surface area greater than the cross-section of the capture section of the device. The protection element may have a proximal connecting member, allowing it to float distal to the vessel in the remainder of the device or distal to the capture section within an external retainer. The protection element may have a collapse delivery condition and may be deployed to expand to a radial extent greater than the radial extent of the expanded capture segment. The fragment filter located at the distal end may take various porous forms, such as a mesh filter, a basket, a series of fibers or filaments, or a series of struts arranged in a volumetric pattern.

[0013] For example, a thrombectomy device capable of removing obstructions and treating stenotic lesions may have an external retainer and a retrieval device. The external retainer may be a generally tubular structure with a maximum radial dimension approximately equal to or greater than the maximum radial dimension of the retrieval device. The outer circumference of the retainer may have a grid of interconnected struts forming a network of closed units. The network of units may have a sufficiently low density to allow thrombi or fragments to be displaced and facilitated into the open internal receiving space of the retainer. When folded within a microcatheter, the external retainer may have a restricted delivery configuration. The retainer may also be constructed of a shape memory alloy to have a pre-defined deployment configuration. When deployed, the external retainer may be configured to apply an outward radial force to the vessel, wherein the maximum radial dimension of the lumen is less than the maximum radial dimension of the external retainer. In one example, the maximum radial dimension of the external retainer may be a diameter of approximately 6.0 mm.

[0014] The external retainer can also be opened to a larger radial diameter at the distal end to provide a maximum opening for improved retrieval capability. The external retainer can also be configured to be detachable from the rest of the device to remain implanted in a narrowed lesion. The implant will support the lesion and maintain the flow lumen through the blood vessel.

[0015] The retrieval device may be at least partially disposed within the lumen of an external retainer. The retrieval device may have a longitudinally extending elongated body with a proximal end, a distal end, and a plurality of struts that converge at an end junction to form adjacent segments along the length of the body. The retrieval device may have a restricted delivery configuration and a deployed configuration. The struts of the adjacent segments may be configured to engage at least a portion of the vascular obstruction in the deployed configuration and may be embedded, restrained, or compressed to obtain strong clamping of the clot or thrombus in the initial step of disengagement from the vessel.

[0016] The treatment device may have a first proximal axis for joint movement of the retrieval device and a second proximal axis enabling joint movement of the external retainer. Being located on separate axes allows the retrieval device and the external retainer to move independently of each other, and allows the retrieval device to be withdrawn spontaneously once a firm grip of the thrombus is achieved. Alternatively, a single axis may be used, in which the retrieval device and the external retainer are deployed and withdrawn together as a unit. Upon clot capture, the retrieval device may be withdrawn completely through the lumen of the external catheter, or it may be pulled back far enough to retain and compress a more robust thrombus within the tip of the external catheter or microcatheter for withdrawal in a sequential manner.

[0017] When the external retainer detaches and is released, the proximal struts of the external retainer can unfold from the detachment point, so that the retainer takes on a roughly tubular shape to engage the lesion and the vessel wall and place them side by side, and the retainer can remain in the blood vessel as an implanted stent.

[0018] In another embodiment, the device may also have a distal debris protection element that is fixedly connected to the distal end of the retrieval device via a shaft or other connecting element. The protection element prevents embolism and may be a distal mesh or support area spanning the luminal space. Fibers or filaments may be added to the support without affecting the device's profile or deliverability. Debris captured by the protection element is extracted from the patient along with the retrieval device.

[0019] This invention also provides a method for combining mechanical thrombectomy and stent implantation. The method may include some or all of the following steps, and these steps do not necessarily have to be in the order cited. Access to the patient's vascular system can be achieved using conventionally known techniques. An access catheter and a microcatheter with a hollow internal lumen are guided to a target site in a cerebral blood vessel where an obstructive thrombus is lodged in a narrow region. Delivered via the microcatheter is a self-deploying external retainer, sized to apply radial force to the wall of the target vessel when deployed. The external retainer may have multiple large units around its circumference and a disengagement point located at its proximal end. A deployable capture portion is provided with the external retainer, the maximum radial dimension of which, when deployed, is smaller than the maximum radial dimension of the external retainer. In an alternative example, the maximum radial dimension of the capture portion when deployed may be the same as or similar to the maximum radial dimension of the external retainer. In yet another alternative, the maximum radial dimension of the capture portion when deployed may be slightly larger than the maximum radial dimension of the external retainer, such that the external retainer will restrain the capture segment when fully deployed. The debris protection element can also be fixedly connected to or connected via a shaft or wire to the distal end of the capture section.

[0020] Aspiration can be applied via one or more catheters used in the procedure. The microcatheter can be advanced across the thrombus using guidewires and standard techniques, the introduced device, and the deployed external retainer and capture segment for deployment within the vessel. The endpoint of the device can be marked during the procedure using radiopaque markers, coatings, or other options known in the art, either along the length of the device or at the proximal and distal ends of the external retainer. The circumferentially oriented units of the external retainer are porous to allow for the displacement and reception of thrombi and lesion fragments within the retainer. The capture segment can be deployed to clamp and capture the thrombus. The external retainer and the capture segment with the captured thrombus can then be aspirated back into the inlet catheter.

[0021] The external retainer and capture segment can be repeatedly advanced through the thrombus to allow for additional capture attempts to clear the vessel as needed. Once the thrombus has been cleared, the external retainer and capture segment can be redeployed to the narrowed area at the target site. The external retainer can then be detached to remain in the vessel as an implanted stent, thereby protecting the flow lumen and dilating the vessel.

[0022] Alternatively, an external retainer may be first released and implanted, and then the captured segment and the captured thrombus may be aspirated back into the inlet catheter and removed from the patient.

[0023] This method may also incorporate the step of positioning a distal fragment protection element near the distal end of the device. The fragment protection element may be securely connected to the distal end of the retrieval device via a tethered shaft or other connecting element. The protection element may remain in place during surgery and deployment of the stent retainer as an implant to prevent embolism until it is removed along with the capture segment.

[0024] 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

[0025] The above and other aspects of the invention will be further discussed with reference to the accompanying drawings, in which like numbers indicate the same structural elements and features in the various figures. The drawings are not necessarily drawn to scale; rather, the focus 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. It is expected that those skilled in the art will be able to conceive of and combine elements from the various drawings to better meet the needs of the user.

[0026] Figure 1 It is a dual-purpose thrombectomy and stent implantation device according to various aspects of the present invention;

[0027] Figure 2 According to various aspects of the present invention Figure 1 Detailed view of the device;

[0028] Figure 3 The invention illustrates aspects thereof. Figure 1 The external retainer of the device shown;

[0029] Figure 4 This illustrates implantation into a target blood vessel according to various aspects of the invention. Figure 1 The external retainer of the device shown;

[0030] Figure 5 The invention illustrates aspects thereof. Figure 1 The device shown includes a capture segment and debris protection elements;

[0031] Figure 6 The invention illustrates aspects thereof. Figure 5 Frontal outline view;

[0032] Figure 7 Another dual-purpose thrombectomy and stent implantation device according to various aspects of the present invention is shown;

[0033] Figure 8 The following diagram illustrates deployment in a blood vessel with occlusive thrombi and stenotic regions according to various aspects of the invention. Figure 7The apparatus shown;

[0034] Figure 9 Another dual-purpose thrombectomy and stent implantation device according to various aspects of the present invention is shown;

[0035] Figure 10 Another dual-purpose thrombectomy and stent implantation device according to various aspects of the present invention is shown;

[0036] Figures 11A to 11E Alternative configurations of fragment protection elements according to various aspects of the present invention are shown;

[0037] Figures 12A to 12D The procedure steps for using an apparatus for performing combined mechanical thrombectomy and stent implantation surgery according to various aspects of the present invention are shown;

[0038] Figure 13 and Figure 14 This is a flowchart outlining a method for performing mechanical thrombectomy and stent implantation procedures using the device, according to various aspects of the present invention. Detailed Implementation

[0039] Specific examples of the invention will now be described in detail with reference to the accompanying drawings, wherein like reference numerals indicate functionally similar or identical elements. The object of the invention is to provide a system or apparatus that offers physicians the advantage of operational flexibility to accommodate complications or unknown situations during endovascular surgery, such as when the occluded vessel has blood clots or potential stenosis areas not detected during angiography. These improvements allow for safer and faster access to complex areas of intracranial arteries to remove occlusions and reduce operative time.

[0040] Approaching various intracranial vessels (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 angiographic materials, rotary valves, 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 systems and methods of the present invention described below. While this specification is primarily in the context of treating intracranial arteries, the system and apparatus can also be used in other bodily pathways.

[0041] Switch to the attached image. Figure 1A device 100 is shown that may include an internal capture segment 110 and an external stent retainer 210, the internal capture segment having a collapsed delivery configuration and an expanded deployment configuration, the external stent retainer at least partially overlapping the internal capture segment 110 longitudinally. The external stent retainer 210 is also radially deployable, and its maximum radial dimension when deployed may be less than, similar to, or greater than the maximum radial dimension of the capture segment 110. The device may have a proximal elongated shaft 64 that allows for user manipulation. The device can be delivered to the target site for mechanical thrombectomy using standard techniques with a guide sheath, access catheter, microcatheter, or other delivery system (not shown). The device may also include a debris protection element 310, which can be deployed distal to the capture segment to provide a physical barrier against any debris that may be released during the procedure.

[0042] A disengagement point 214 may be provided for the device 100 near the proximal end of the support retainer 210. The disengagement point may be remotely actuated by the user to detach the support retainer from the rest of the device. Any method may be deployed to achieve disengagement, allowing the support retainer to be physically detached from the rest of the system or device.

[0043] At least some or more of the capture segment 110 and the support retainer 210 may be made of nitinol or another shape memory material with sufficient elastic strain capacity, such that the device 100 does not exceed its elastic limit when it is in a collapsed delivery configuration within the delivery system. This strain capacity allows the device to be effectively “spring-loaded” within the microcatheter or delivery system, enabling it to self-deploy to engage the clot when deployed from the distal end of the delivery system.

[0044] By adding alloying elements or including radiopaque markers or coatings, components of device 100 can be made visible under fluoroscopic examination. For example, the device may have a distal radiopaque coil 67 and a proximal radiopaque coil 66 that are located near the end of the capture segment during thrombectomy.

[0045] Figure 2 yes Figure 1 A side view of the device. At least some portions of the clot-catching segment 110 and the filter element 314 may reside within the lumen of the support holder 210. The catching segment may be a stent retriever, and the longitudinal axis 228 of the catching segment 110 may coincide with or be offset from the longitudinal axis 228 of the support holder 210. The distal end 218 of the support holder may be an open end, or its profile may be tapered. If open, there is no distal connection point between the support holder 210 and the catching segment 110. This allows the catching segment to move radially upon contact with the clot.

[0046] The filter element 314 of the clot capture segment 110, stent retainer 210, and fragment protection element 310 may have a collapsed configuration for delivery and an expanded configuration for clot retrieval, flow restoration, and fragment protection. The elongated shaft 64 of the device may be a tapered wire and may be constructed from stainless steel, MP35N, nitinol, or other materials with sufficiently high tensile strength and modulus to allow for responsiveness and consistent traceability of the device in the blood vessel.

[0047] The stent retainer 210, the clot capture segment 110, and the distal portion of the fragment filter element 314 together define a three-dimensional protective structure to substantially prevent clots or clot fragments from dislodging from the distal side of the device. The fragment filter element 314 can take any of a variety of forms and can have a structure with surfaces that can be configured as clot-blocking surfaces. In one example, the fragment filter may have a spoke arrangement formed by a combination of struts 316. In other cases, the strut frame may be covered with a fibrous mesh or braid that allows fluid in the blood vessel to pass through but prevents distal migration of larger solids. This protective structure prevents clots or clot fragments that have entered the internal capture segment 110 or the receiving space 220 between the internal clot capture segment and the external stent retainer frame 210 from dislodging.

[0048] Figure 3 It shows Figure 1 The example shown features an externally deployable support retainer 210. This retainer may have a distal end 218, a proximal end 216, and a proximal shaft 212 that allows manipulation. In one example, the support retainer 210 may have a series of interconnecting struts 229, 230, 231 that define a generally tubular structure around a longitudinal axis 228. Some struts 230 may terminate at a crown without a distal connecting element, while other struts 231 may terminate at a joint. The support retainer 210 may also have connecting arm struts 229 that define an outer surface generally parallel to the longitudinal axis 228. The struts may form an external circumferential network of a closed unit through which one or more blocks can be radially displaced inward to enter a receiving space 220.

[0049] The distal end 218 of the stent retainer 210 may be defined by a series of coronal or distal undulating struts 226. The undulating struts may open with a large radius of curvature to achieve non-traumatic contact with the vessel wall. The struts at the proximal end 216 of the stent retainer may taper to a disengagement point 214 on the proximal axis 212. The disengagement point may be configured to allow the stent retainer to disengage from the rest of the device for use as a stent in the patient, such as for implantation of ICAD lesions.

[0050] The disengagement point 214 of the stent retainer 210 may have one or more bushings, partial bushings, or sheaths that may be fitted over the stepped feature of the shaft 212, such that they form a mechanical lock that prevents the connector from disintegrating during tension or compression. Alternatively, the bushings may be fitted over a notch on the capture portion 110. To disengage the stent retainer, the disengagement point may be actuated mechanically, electrically, or otherwise, allowing the stent retainer to support a narrowed area. Once released from the disengagement point, the stent retainer is held in place in the blood vessel by an outward radial force applied to the vessel wall.

[0051] In another example, the support retainer may be a support having multiple elastic metal strands formed in a braided or mesh pattern. The strands or struts of the support may extend longitudinally and be woven in a predominantly helical configuration, with the central axis or centerline of the resulting tubular structure serving as a common axis. A first set of strands may be wound in one direction while being axially displaced relative to each other. A second set of strands may be wound in a direction opposite to the first set of strands while also being axially displaced relative to each other.

[0052] When an element is described and visualized as a tubular structure in the accompanying drawings and is generally shown as a substantially straight cylindrical structure, the terms "tubular" and "tube" should be interpreted broadly as used herein. They are not intended to be limited to structures that are perfect cylinders or have a perfectly circular cross-section or a uniform cross-section over their entire length.

[0053] The stent retainer 210 can be configured such that it unfolds to a predetermined outer diameter upon deployment and possesses sufficient radial force to well embed into the lesion while displacing the thrombus into the receiving space. Low-level support in the stent retainer can be achieved by minimizing the possible surface contact area between the interconnected retainer struts 224 and the thrombus or lesion. In one example, a less dense network of cells with fewer struts can be utilized. In another example, the struts of the retainer structure can be bent radially inward toward the longitudinal centerline or axis of the device in an oscillating periodic manner to achieve a localized reduction in force and contact area with the thrombus. This localized reduction can also be achieved by having multiple axial and / or radial alignments between the distal end 218 and the proximal end 216 of the retainer.

[0054] The raw materials for the stent retainer 210 can be in various forms, such as wire, strip, sheet, or tube. The deployable body of the stent retainer can be made of a material that can automatically recover its shape once released from a high-strain delivery configuration. Hyperelastic shape memory materials such as nitinol or alloys with similar properties are particularly suitable. These materials have sufficient elastic strain capacity to ensure that the retainer does not exceed its elastic limit when constrained in a collapsed delivery configuration within a microcatheter or externally inserted catheter. This elastic strain capacity allows the retainer to be effectively spring-loaded within the external catheter, enabling it to self-deploy when deployed from the distal end of the external catheter. In a standalone configuration, the frame can be constructed of wire, allowing the use of non-hyperelastic materials such as stainless steel alloys, as the wires will move freely and independently of each other.

[0055] In one example, a nitinol tube or sheet can be laser-cut and then heat-set to form a framework of struts and connecting members. This tubular structure can be heat-treated on a mandrel to a suitable temperature to structurally impart stress relief, causing the tube to conform to the shape of the mandrel. In these ways, the elastic properties of the stent braid can be controlled, allowing the stent to facilitate the implantation process and maintain stiffness and strength throughout the implant's desired lifespan. The winding of the braided strands can also be dense enough to provide a stable configuration that supports the entire inner diameter of the vessel during implantation.

[0056] The stent retainer 210 may be bare metal, or the material may be coated with a non-pharmacological coating, such as silicon carbide, carbon, and titanium nitrides and oxides. The coating may be hydrophilic or have additives that effectively enhance the lubricity of the mesh braid of the stent implantation device 112 to achieve more non-invasive navigation of the vascular system. In another example, the coating may be a hydrogel or contain soluble particles in a polymer matrix that soften or completely dissolve upon exposure to an aqueous medium such as blood. In other cases, the stent has been coated with a biodegradable drug-eluting coating designed to inhibit restenosis. For example, these may be antiplatelet agents or anticoagulants. These agents are eluted from the matrix of the coating upon exposure to an aqueous medium and help prevent the implanted stent 128 from forming potential lesions that could lead to future clot formation.

[0057] Interconnecting struts 224 can be formed as a single structure or as a combination of substructures. The distal coronal or undulating strut 226 can have an open profile. The receiving space 220 in the lumen of the stent retainer can be manufactured large enough that there is sufficient space when a thrombus is pushed through the unit or by the circumference of the unit, without significantly compressing the unit and changing the coefficient of friction.

[0058] In most cases, the device is strictly intended for use in thrombectomy. However, in approximately 40% of cases involving certain patient populations, it may be desirable to implant a stent to support and dilate the targeted stenosis. Following recanalization, the disengagement point can be configured to release the stent retainer from the remainder of the device. The outward radial force provided by the stent retainer against the vessel wall allows the vessel to remain stationary and can be used to provide local support or even dilate the vessel to maintain the fidelity of the luminal flow path. Once the stent retainer has been implanted as a stent, the remainder of the device, including the capture segment 110 and the fragmentation protection element 310, can be removed from the patient.

[0059] Figure 4 An example of a stent retainer 210 is shown, which is implanted in a blood vessel 20 to expand a narrowed region 50. The radial dimension of the stent retainer can be selected to customize the applied radial force, such that the radial dimension 26 of the vessel lumen 22 in the lesion is restored to a certain percentage of the nominal radial dimension 24 of the unaffected region adjacent to the lesion. This percentage may depend on the amount of plaque accumulated in the lesion. The friction generated by the radial force applied by the deployed stent retainer can hold the stent in a longitudinal position within the blood vessel.

[0060] The capture segment 110 may have a proximal elongated body 124 and a distal filter element 314 for debris protection, such as Figure 5 As shown. The elongated body may have a proximal end 116, a distal end 118, a longitudinal axis 122, and a proximal axis 112. When deployed, the longitudinal axis 122 may or may not coincide with the longitudinal axis 228 of the stent retainer. The elongated body may be of various shapes and may have tapered segments, open segments, and open or closed ends. The elongated body may be configured to have an unfolded diameter in the range of about 1.5 mm to 5.0 mm. The elongated body may have a strut 120 or a deployable frame of the coronal portion configured to clamp and remove occlusive clots. The strut may have a bend forming a neck constriction region, allowing different longitudinal segments of the elongated body to apply varying radial forces to the clot. The variable radial forces allow the elongated body to establish a stronger clamping force on the clot between segments, thereby making it easier for the clot to initially disengage from the vessel wall. The filter element can be radially unfolded to a greater extent compared to the elongated body 124 in deployment condition.

[0061] In another example, when deployed to a configuration, the elongated body 124 of the capture segment 110 may have a generally tubular shape positioned around a longitudinal axis 112 and may be configured to apply a strong radial force to open a flow lumen through the clot. This smaller flow path restricts initial flow, allowing blood supply to be gradually restored to the affected area, thus reducing the risk of reperfusion injury. Alternatively, the elongated body 124 of the capture segment 110 may have a planar structure that may oscillate periodically or extend in a helical manner around the longitudinal axis 112. Constructed in this way, the elongated body can expand and contract in response to the forces of thrombectomy and clamp or compress the clot between adjacent peaks of the structure to extract the clot from the vessel.

[0062] Figure 6 It is in a deployment configuration. Figure 5 The example shown is an end view of the capture segment 110 and the fragment protection element 310. In one configuration, at least a portion of the fragment protection element can be deployed to a greater extent than the clot capture segment to provide a downstream surface to intercept released clot fragments. In the example shown, the fragment protection element may have a frame of struts 316 arranged in a spoke-like pattern extending radially outward from the central fragment protector hub 320 to form a physical barrier, thereby preventing distal migration of debris caused by thrombectomy. The strut frame may have a flexible or rigid construction, or the struts may be configured to hinge or fold around a plane to occupy more space downstream of the capture segment. The hub may be a simple tubular member extending distally from the capture segment, or it may be a coiled wire harness or mesh. The struts 316 of the frame may have open or protruding segments and may be constructed with overlapping helical patterns to enhance fragment protection.

[0063] Similar to some previous examples, this invention discloses an additional design with a dual deployable member for thrombectomy and stent implantation. Figure 7 The diagram illustrates an apparatus having a first internal deployable member 110 that can be used as a clot-catching segment 110 and a second external deployable member 210 that can be used as a stent. The internal member may be a stent thrombectomy device substantially disposed within the lumen of the external member. The internal member may have a deployable frame of a strut or coronal portion configured to clamp and remove occlusive clots. The characteristics of the internal and external members can be customized independently of each other. For example, in a design where both members include connecting struts, the shape and porosity level of the internal member strut frame 120 may be completely different from the shape and porosity level of the external member interconnecting strut 224. Thus, the stiffness and radial force of the internal member can be configured to clamp the clot, while the external member is configured to support the vessel.

[0064] The receiving openings of the external retainer 210 can be large, providing minimal resistance to clot movement relative to the retainer. The clot can be locally compressed as the external stent retainer deploys, and the receiving openings allow the thrombus or debris to bypass compression by displacing into the internal receiving space 220 of the retainer. This reduces the radial force exerted on the vessel by the stent retainer in the stenotic region, meaning less force is required to retrieve the thrombus, which in turn results in less vascular trauma and tension on the distal vascular bed. The radial force of the retainer can act strongly at the small diameter, similar to compressing a spring, to displace the thrombus. The radial force can be weaker at the larger diameter, gently pressing on the lesion and vessel wall.

[0065] The distal end 118 of the internal component capturing segment 110 may extend distally to the distal end 218 of the external retainer 210. The applied suction may push the clot proximally to engage the strut frame 120 of the captured segment.

[0066] The internal and external components can be delivered from the same microcatheter 70 and guided through the lumen of the guide catheter or entry catheter 30 to the target site in the patient's blood vessel. The device may have separate axes that allow independent movement of the internal and external components. A first proximal axis 112 enables articulation of the capture segment 110, and a second proximal axis 212 enables articulation of the stent retainer 210. Having separate axes allows the user to adapt, for example, to a slightly different axial position for grasping the clot than the axial position most effective for restoring the flow path. Using separate axes allows clot retrieval independent of stent retainer deployment. After clot retrieval, the physician may choose to leave the stent retainer in place for a short period to assess the risk of vessel re-occlusion before deciding whether to remove and deploy the stent retainer as an implant. If the physician chooses not to deploy the stent retainer, it can be reinserted and removed from the patient.

[0067] Figure 8 It shows the deployment within a portion of the blood vessel 20. Figure 7The device includes a portion having an occlusive thrombus 40 lodged in a stenotic lesion 50. When the maximum radial dimension of the target lesion is less than the maximum radial dimension of the stent retainer 210, the retainer can be configured to apply an outward radial force when deployed within the lesion. The external retainer can expand the lesion as the capture segment 110 unfolds to clamp the thrombus. A radiopaque marker or coil 67 can mark the distal end of the device, allowing the user to adjust the longitudinal position of the capture segment using a second proximal axis 212, independent of the radial force applied by the external retainer. The stent retainer can begin to compress and displace the thrombus through the unit formed by the strut as the strut 224 unfolds. The large unit allows the thrombus to avoid compression by displacing a large portion of the thrombus through a unit opening in the stent retainer wall. The thrombus can also be aspirated through the open distal tip of the retainer.

[0068] Figure 9 Another example of a two-layer device is shown, wherein the distal end 118 of the elongated body 124 of the capture segment 110 longitudinally overlaps the proximal end 216 of the support retainer 210. As in other examples, the support retainer may have a plurality of interconnected struts 224 forming an external circumferential network of closed units. The capture segment 110 may be secured to a common shaft 64 at its proximal end 116, while the support retainer 210 may be secured distally to the shaft 64 at a disengagement point 214. The proximal capture segment 110 may be extended to approximately equal to or less than the maximum radial dimension 114 of the maximum radial dimension 222 of the distal support retainer. In another configuration, the capture segment 110 may be extended to slightly larger than the maximum radial dimension 114 of the maximum radial dimension 222 of the support retainer 210, such that the capture segment is radially constrained by the support retainer.

[0069] The maximum radial dimension of the support retainer when deployed can be at least 20% larger than the maximum radial dimension of the deployed capture segment. In other cases, the support retainer can be two or more times the diameter of the capture segment. The support retainer can have a network of interconnecting struts 224 that form large closed units, thereby providing a smaller radial force along the distal length of the device.

[0070] The capture segment may be a frame of struts 120 organized into a series of adjacent segments. The struts may be organized into closed units, or may include one or more bends or undulations along their length, such that they engage different portions of the clot or thrombus. Units and / or bends may have different dimensions at different longitudinal segments of the capture segment. In one example, a segment of the capture segment may consist of struts 120 and units in a flat pattern, which is then configured into a wave-like or undulating shape 312 when viewed from the side. Alternatively, adjacent segments may be longitudinally aligned to cause the struts of the segment to collapse when subjected to longitudinal tensile or compressive loads. Such variations in the radial force applied by the capture segment may embed or compress the clot between different portions of the strut frame. Interpenetration or compression may also occur when the device is later pulled back and collapsed into the intermediate or inlet catheter after capturing the clot. Compression action may be useful for enhancing the device's grip on fibrin-rich clots. The contraction action can also lengthen the clot and pull it away from the wall of the lesion or blood vessel, thereby reducing the removal force required.

[0071] The device may have a fragment protection element 310 downstream of the capture segment 110 and located inside the stent holder 210. The filter element 314 of the fragment protection element 310 provides physical protection against any embolism caused by the clot retrieval procedure. A flexible connecting member 312 can connect the filter element 314 to the distal end 118 of the capture segment, meaning the longitudinal position of the protection element is controlled by the proximal capture segment axis 112.

[0072] exist Figure 10 In another example of the clot retrieval and stent implantation device 200 shown, a deployable external retainer may also be configured to engage with and retrieve the clot. The device may have an external retainer 210 having a structure that engages and captures the occlusive clot when deployed from a delivery configuration to a deployment configuration. The external retainer may have a proximal end 216, a distal end 218, and a shaft 212 for articulation of the device. A disengagement point 214 may be located at the junction of the distal ends of the shaft, and the proximal end of the external retainer may be configured to disengage the external retainer for implantation as a stent.

[0073] The external retainer 210 may have a series of interconnecting struts 224, forming an external circumferential network of large closed units. The interconnecting struts may include connecting members extending through the interior of the external retainer to provide additional surfaces for capturing and clamping clots. The struts may be shape memory alloys such as nitinol, allowing them to expand to a desired maximum radial dimension 222 when deployed in the vessel. The interconnecting struts are cut in a manner to engage and clamp clots during standard thrombectomy. During this engagement, the clot may be partially located within the unit openings of the interconnecting struts 224 and partially within the receiving space of the external retainer or the internal lumen 220.

[0074] Similar to the prior designs disclosed in this specification, the retrieval and stent implantation device 200 may have a fragment protection element 310, which may be deployed near the distal end of the external retainer to provide a physical barrier to prevent downstream migration of debris released during clot retrieval. The fragment protection element may be connected to the shaft 212 via a flexible connecting member 312. The connecting member may be an extension of the shaft 212, or may itself have struts or an undulating corrugated pattern that helps to hold the clot as it unfolds and contracts under retrieval force.

[0075] Once the desired level of recanalization is achieved in a retrieval attempt using device 200, the physician may wish to further treat the stenotic area, such as an ICAD lesion. The device can be cleaned with saline or other media and reintroduced to the target site using a thrombectomy delivery system or other suitable methods known in the art. As it is advanced through the lesion, the external retainer 210 can be deployed and subsequently released via actuation release point 214. The maximum diameter or radial dimension 222 of the external retainer at deployment can be designed to minimize the chronic outward force exerted on the stenosis, which is important for typically fragile neurovascular vessels. In one example, the maximum diameter of the deployed external retainer may be configured to be approximately 2.5 mm, but in other examples it may be up to 4.0 mm. Once implanted as a stent, shaft 212 can be pulled to traction the connecting member 312 and retrieve the fragment protection element 310 from the patient.

[0076] The outer retainer 210 and the capture segment 110 shown in the accompanying drawings and discussed herein are used to illustrate a single aspect of the invention. Of course, the invention is applicable to outer retainers and capture segments of various shapes and sizes, and can be made from a single segment or from multiple segments.

[0077] Figures 11A to 11E Various alternative designs for the construction of the debris protection element 310 are shown. The debris protection feature can be formed by attaching a shaped wire or support strip 316. The wire or support strip can have various shapes or orientations to better cover the open end of the support holder when the device is deployed. Figure 11A , Figure 11C and Figure 11D In some of the examples shown, the wires or struts are organized into a three-dimensional structure, wherein the wires or struts flare radially outward to form a shape equal to or larger than the cross-section of the internal deployable capture segment of the device. The wires or struts may be an interconnecting network, or they may form a spoke-like arrangement extending from the common hub 320 of the debris protector. Figure 11B and Figure 11EIn another set of examples shown, the threads or struts are combined together to form an interwoven fiber filter mesh 318. The mesh may be woven with an organized pattern, or the threads or fibers may be entangled into bundles.

[0078] Figures 12A to 12D One possible sequence of use of the apparatus as disclosed herein is shown. Figure 12A An example of a device for navigating to a target vessel 40 within a neurovascular system is shown. The delivery system can access the site using an access catheter 30, and the device can be loaded into a microcatheter 70 for deployment. The target site can be an occluded vessel as shown, wherein the obstructive clot 40 is lodged in the lumen 22 of the vessel, which is also narrowed due to an intracranial stenosis in the form of a lesion 50 formed by the accumulation of atherosclerotic plaques.

[0079] The microcatheter 70 can be advanced until it is positioned distal to the clot 40. Once in place, the microcatheter can be withdrawn proximally, allowing the stent retainer 210 and the capture portion 110 to deploy within the clot and on either side of the clot, as... Figure 12B As shown. The deployment of the stent retainer displaces the clot and dilates the lumen 22 of the vessel 20, allowing flow to be restored. The strut of the capture segment 110 engages with and holds the clot.

[0080] exist Figure 12C In this process, capture segment 110 has begun to aspirate clot 40 proximally from the target vessel 20. Aspiration may be accompanied by suction from a separate aspiration catheter or from a guiding or access catheter 30 to help maintain a firm grip on the clot and prevent fragment loss and migration. The capture segment may have adjacent segments of varying shapes, such that the force applied to the clot is variable as the capture segment is retrieved back into the access catheter. Variations in force between adjacent segments can result in a tightening action, which is more effective in maintaining grip on particularly firm or irregular clot morphologies. In some cases, the stent retainer 210 will be withdrawn into the access catheter 30 as a unit along with the capture segment 110, or, when using multiple axes, they can be manipulated and positioned individually. Alternatively, the device can be held in place and at least partially re-inserted by advancing the access catheter distally.

[0081] In cases where a narrowed area has been identified, the user can disengage the stent retainer 210 as an implant in the lesion 50, such as... Figure 12DAs shown. After the occlusive clot has been safely removed, if the device is not yet in place, it can be pushed back across the stenosis to align the stent retainer with the lesion in the vessel. The outer diameter of the stent retainer and the shape of the outer retainer frame are selected to provide an effective amount of support to the target vessel 20, thereby maintaining a reconstructed flow path across the narrowed stenotic region. For example, the desired flow path diameter in the stent region is achieved when the first diameter of the constricted portion of the vessel containing the lesion increases to 75% of the second diameter in the portion of the vessel adjacent to the first diameter. At the end of the procedure, the remaining portion of the double-layer device can be withdrawn from the patient.

[0082] Figure 13 and Figure 14 Each of these is a flowchart of a methodological step that includes performing a mechanical thrombectomy. These methodological steps can be implemented by any of the devices and / or equipment described herein.

[0083] See Figure 13 The method 1300 outlined herein, in step 1310, involves access to a patient's blood vessel using conventionally known techniques, and the positioning of an access catheter and microcatheter with a hollow internal lumen within a neurovascular vessel containing a stenotic lesion and an occlusive clot. The access catheter may be an external guiding sheath or aspiration catheter as described herein, or alternatives known to those skilled in the art. A double-layered thrombectomy and stent implantation device may be positioned within the microcatheter. In step 1320, the device may have a self-deploying external retainer comprising multiple large unit openings and disengagement points configured to release the external retainer from the remainder of the device for stent implantation. In step 1330, a second layer may include an internal capture segment within the external retainer, the maximum radial dimension of which is less than, equal to, or slightly larger than the maximum radial dimension of the external retainer, depending on the application. The capture segment may have a deployable network of struts for clamping and removing the clot from the vessel.

[0084] The device may also have additional components that facilitate endovascular surgery. In step 1340, a fragment protection element may be positioned distal to the capture segment to occupy space across the vessel lumen and prevent distal dislodgement of fragments released during the procedure. The protection element may be attached to the capture segment using a flexible shaft or wire and may take any of a variety of forms suitable for this purpose that are familiar to those skilled in the art. Additionally, another step 1350 may involve adding one or more radiopaque markers to key points on the device so that they are easily visible under fluoroscopic examination during the procedure. For example, markers may be added to the proximal and distal ends of the device to mark the distal treatment point during the procedure.

[0085] refer to Figure 14In the method 1400 outlined herein, in step 1410, a microcatheter is advanced from the inlet catheter toward and through the occlusive clot, and the external retainer and capture segment are withdrawn to unfold from the microcatheter. The large unit of the external retainer displaces the thrombus into the internal receiving space. In step 1420, the capture segment unfolds to engage and clamp the clot. Step 1420 may also include a step of retracting the thrombectomy and stent implantation device with the captured clot proximally back into the lumen of the microcatheter and / or inlet catheter for removal from the patient. If additional capture attempts are required to adequately clear the vessel, the aforementioned steps may be repeated as needed.

[0086] To treat narrowed areas in a blood vessel, the user can redeploy the external retainer and capture segment to the target site and align them with the lesion, as shown in step 1430. The detachment point can be actuated to retain the deployed external retainer as an implanted stent in the blood vessel. In steps 1440 and 1450, the remaining portion of the device (including the capture segment) can be withdrawn into the access catheter and removed from the patient.

[0087] 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.

[0088] "Comprising," "containing," or "including" means that at least the named compound, element, particle, or method step is present in the composition, article, or method, but does not exclude the presence of other compounds, materials, particles, or method steps, even if the other such compounds, materials, particles, or method steps have the same function as the named ones.

[0089] In describing the example embodiments, terminology is used for clarity. It is intended that each term 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 a method does not exclude the presence of additional method steps or intermediate method steps between those explicitly identified steps. Some steps of the method may be performed in an order different from that described herein without departing from the scope of the disclosed art. Similarly, it should be understood that reference to one or more components in an apparatus or system does not exclude the presence of additional components or intermediate components between those explicitly identified components. For clarity and brevity, not all possible combinations are listed.

[0090] 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 ±20% of the enumerated values, for example, “about 90%” may refer to a range of values ​​from 71% to 99%.

[0091] The description contained herein is an example of embodiments of the invention and is not intended to limit the scope of the invention in any way. While specific examples of the invention have been described, various modifications may be made to the apparatus and methods without departing from the scope and spirit of the invention. For example, while the examples described herein relate to specific components, the invention includes other examples such as using various combinations of components to achieve the function, using alternative materials to achieve the function, combining components of the various examples, combining components of the various examples with known components, etc. The invention contemplates replacing the components shown herein with other well-known and commercially available products. These modifications will generally be apparent to those skilled in the art to which this invention pertains and are intended to fall within the scope of the following claims.

Claims

1. A device for treating occlusive and stenotic lesions in the vasculature, the device comprising: a capture segment comprising: an elongated body; a proximal end; a distal end; a collapsed delivery configuration; and an expanded deployed configuration; and a stent holder comprising a collapsed delivery configuration and an expanded deployed configuration; wherein the stent holder is configured to be detached from the device to remain implanted in the lesion upon removal of the capture segment from the lesion, wherein the device further comprises a debris protection element at the distal end of the capture segment, the debris protection element comprising: a connecting member; and a distal debris filter expandable to at least the same radial dimension as the capture segment in the expanded deployed configuration, wherein the connecting member connects the debris protection element to the capture segment, and wherein the connecting member is in an undulating wave pattern.

2. The device of claim 1, wherein the stent holder is a stent.

3. The device of claim 1, wherein the capture segment is a stentriever configured to engage one or more portions of an occlusive thrombus upon movement from the collapsed delivery configuration to the expanded deployed configuration.

4. The device of claim 1, wherein the stent holder and the capture segment share a common proximal shaft.

5. The device of claim 1, wherein the stent holder further comprises a plurality of interconnected struts forming an outer circumferential network of closed cells.

6. The device of claim 5, wherein at least two of the plurality of interconnected struts are longitudinally aligned.

7. The device of claim 1, wherein the capture segment comprises a strut framework forming an outer network of closed cells, wherein at least a portion of the strut framework is configured to embed and compact at least a portion of a thrombus in the expanded deployed configuration as the capture segment is pulled back into an outer catheter.

8. The device of claim 1, wherein the stent holder is configured to exert an outward radial force to expand within a lesion upon deployment.

9. The device of claim 1, wherein a first proximal shaft enables articulation of the capture segment, and a second proximal shaft enables articulation of the stent holder.

10. A device for treating occlusive thrombus and stenotic regions in the vasculature, the device comprising: a proximal shaft; and an outer holder comprising: a generally tubular structure having a collapsed delivery configuration, an expanded deployed configuration, and a maximum radial dimension; wherein the outer holder is configured to exert an outward radial force to expand within a stenotic region upon deployment; wherein the outer holder is further configured to be detached from the device to remain implanted in the stenosis, wherein the device further comprises a distal debris protection element fixedly connected to the proximal shaft by a connecting member, and wherein the connecting member is in an undulating wave pattern.

11. The device of claim 10, wherein a maximum radial dimension of the expanded outer cage is about 6.0 mm in diameter in the expanded deployed state.

12. The device of claim 10, wherein a distal end of the outer cage flares to a radial dimension greater than the maximum radial dimension of the outer cage.

13. The device of claim 10, wherein the outer cage is an implantable stent.

14. The device of claim 10, wherein the outer cage further comprises a structure of interconnected struts.

15. The device of claim 14, wherein the interconnected struts of the outer cage are configured to engage at least a portion of the thrombus in the expanded deployed configuration.

16. The device of claim 14, wherein the interconnected struts of the outer cage are configured to embed and compact at least a portion of the thrombus in the expanded deployed configuration.

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