Patent Application
20240206897
The present technology relates generally to devices and methods for increasing or restoring patency to body lumens. Some embodiments of the present technology relate to devices and methods for removal of clot material from blood vessels and/or for treatment of atherosclerosis.
Blood vessels can become occluded by emboli, e.g., thrombi. For example, intracranial arteries can become occluded by thromboembolisms. Disruption of blood flow by the occlusion can prevent oxygen and nutrients from being delivered to tissues downstream of the occlusion. Deprivation of oxygen and nutrients to tissue distal to an occlusion can impair proper function of the tissue, and may result in cellular death. Cellular death increases with duration of the occlusion.
Blood flow can also be disrupted due to atherosclerosis, in which a build-up of plaque in the blood vessel reduces vessel patency and inhibits blood flow. In blood vessels in the brain, intracranial atherosclerotic disease (ICAD) can affect cerebral arteries and lead to strokes.
Many physicians currently perform thrombectomies (i.e. clot removal) with stents to resolve ischemic stroke. Typically, the physician deploys a stent or other mechanical thrombectomy device into the clot in an attempt to push the clot to the side of the vessel and and/or retrieve the clot to re-establish blood flow. However, in some instances, what appears to be occlusion due to a thrombus may in fact be a stenotic region of a blood vessel due to intracranial atherosclerotic disease (ICAD). In such cases, blood flow may be improved upon initial deployment of the thrombectomy device, only for the blood flow to again be occluded once the thrombectomy device is retracted and the walls of the vessel resume their narrowed state. In such instances, the physician may determine that blood flow disruption is due to ICAD only when multiple passes of a thrombectomy device are unsuccessful. Following this determination, the physician may then choose to dilate the stenotic region using either balloon angioplasty or an implant such as a balloon-mounted stent. This involves retracting and removing the thrombectomy device from the treatment site, then delivering a guide wire past the stenotic region, and finally delivering either an angioplasty balloon or a balloon-mounted stent delivery system over the guide wire to the treatment site. As such, this approach requires the physician to re-navigate to the treatment site after removing the thrombectomy device.
Examples of the present technology provide a single treatment system capable of deploying both a mechanical thrombectomy device (e.g., a stent retriever) and/or an angioplasty device (e.g., an angioplasty balloon, balloon-mounted stent, or other suitable device). For instance, a delivery catheter carrying the angioplasty device can be positioned at or adjacent the treatment site. The mechanical thrombectomy device can be delivered through the delivery catheter to the treatment site. In operation, once the thrombectomy device is deployed and the clinician determines that balloon angioplasty and/or stenting is needed, the delivery catheter of the angioplasty balloon and/or stent can be distally advanced over the thrombectomy device to the treatment site. The angioplasty balloon or stent is then used to open the stenosis at the treatment site without retraction of the stent retriever. In this manner, the push wire of the thrombectomy device can serve as a guidewire over which the delivery catheter (carrying the angioplasty device) is advanced. This configuration allows for a single treatment system that can separately and/or sequentially deploy a thrombectomy device and/or an angioplasty device without requiring re-navigation to the treatment site.
Additionally or alternatively, this configuration allows for initial delivery and deployment of a mechanical thrombectomy device and then, in the event that thrombus removal is unsuccessful (e.g., due to ICAD), an angioplasty balloon and/or stent catheter can be advanced over the pushwire of the mechanical thrombectomy device to the treatment site, where the angioplasty balloon and/or stent can be deployed to open the stenosis without requiring the mechanical thrombectomy device to be removed. A further benefit of this approach is that the mechanical thrombectomy device, while in an expanded state in apposition with the vessel wall, can maintain positioning at the stenosis, thereby allowing for blood flow while the angioplasty balloon and/or stent catheter is being delivered.
The present technology is illustrated, for example, according to various aspects described below. Various examples of aspects of the present technology are described as numbered clauses for convenience. These are provided as examples and do not limit the present technology. It is noted that any of the dependent clauses may be combined in any combination, and placed into a respective independent clause. The other clauses can be presented in a similar manner.
Additional features and advantages of the present technology are described below, and in part will be apparent from the description, or may be learned by practice of the present technology. The advantages of the present technology will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on illustrating clearly the principles of the present disclosure.
As noted above, it can be advantageous to provide a single treatment system capable of deploying both a mechanical thrombectomy device (e.g., a stent retriever) and an angioplasty device (e.g., an angioplasty balloon, balloon-mounted stent, or other suitable device) to an intravascular treatment site. This can be particularly beneficial in instances in which a treatment site may be either a lesion (e.g., a stenotic region of a blood vessel) or an occluded portion of a vessel due to a thrombus, as these two cases may be difficult to distinguish under conventional visualization and diagnostic techniques. Providing a single treatment system that can deploy a mechanical thrombectomy device and then, if mechanical thrombectomy is unsuccessful, deploy an angioplasty device, can reduce the complexity of interventional procedures and improve the success rate in restoring patency to the affected blood vessel.
The thrombectomy assembly 110 includes a thrombectomy device 112 (e.g., an expandable device such as a stent retriever) coupled to distal end portion of a core member 114. The core member 114 may include an elongate body, for example a wire, tube (e.g., a hypotube), combinations thereof, or other suitable structure for pushing, pulling, and/or otherwise manipulating the thrombectomy device 112. In operation, the thrombectomy device 112 can be deployed at or adjacent a thrombus in a blood vessel, and the thrombectomy device 112 can be configured to engage, interlock with, grasp, or otherwise facilitate capture and removal of the thrombus. The thrombectomy device 112 can then be proximally retracted to remove the thrombus from the blood vessel and restore blood flow therethrough.
The core member 114 can extend between the thrombectomy device 112 and the proximal portion 102a of the treatment system 100. Optionally, the thrombectomy assembly 110 further includes a microcatheter 116 which slidably receives the core member 114 therein. The microcatheter 116 can be configured to be positioned over the thrombectomy device 112 while the thrombectomy device 112 is in a low-profile, constrained configuration. To deploy the thrombectomy device 112, the microcatheter 116 can be proximally retracted relative to the thrombectomy device 112 (and/or the thrombectomy device 112 can be distally advanced relative to the microcatheter 116). Once the thrombectomy device 112 is positioned outside the microcatheter 116, the thrombectomy device may self-expand into the expanded, unconstrained configuration as shown in
The delivery catheter assembly 120 includes a delivery catheter 122 and an expandable member 124 carried by a distal portion of the delivery catheter 122. The expandable member 124 can be an angioplasty device configured to treat atherosclerosis. Examples of such devices include angioplasty balloons, balloon-mounted stents, self-expandable stents, or any other suitable angioplasty device. The delivery catheter 122 can include an inflation lumen (not shown in
As noted above, the treatment system 100 can include the microcatheter 116 and the delivery catheter 122. In some examples, the system 100 can additionally include a guide catheter 140, which can be sized and configured to slidably receive the delivery catheter 122 within its lumen. As such, the delivery catheter 122 can be slidably disposed within the lumen of the guide catheter 140, the microcatheter 116 can be slidably disposed within the lumen of the delivery catheter 122, and the core member 114 can be slidably disposed within the lumen of the microcatheter 116.
With continued reference to
According to some embodiments, the bodies of the catheters can be made from various thermoplastics, e.g., polytetrafluoroethylene (PTFE or TEFLON®), fluorinated ethylene propylene (FEP), high-density polyethylene (HDPE), polyether ether ketone (PEEK), etc., which can optionally be lined on the inner surface of the catheters or an adjacent surface with a hydrophilic material such as polyvinylpyrrolidone (PVP) or some other plastic coating. Additionally, either surface can be coated with various combinations of different materials, depending upon the desired results.
As noted above, the thrombectomy assembly 110 includes a thrombectomy device 112 coupled to a distal end portion of a core member 114 (e.g., a pushwire, hypotube, or other suitable elongate manipulation member). In some embodiments, the core member 114 is coupled to the thrombectomy device 112 at a connection point 118. In various embodiments, the connection point 118 can take any suitable form, such as a snap-fit engagement, a crimped tubular member, a laser weld, etc. Optionally, the connection point 118 can be radiopaque to facilitate visualization under fluoroscopy. As shown in
The thrombectomy device 112 can be, for example, an expandable member, a self-expandable stent, basket, mesh, filter, or other suitable structure. In various embodiments, the thrombectomy device 112 can have a low-profile state for delivery through the microcatheter 116 and an expanded state when it is released from the microcatheter 116 or otherwise deployed at the treatment site. In the expanded state, the thrombectomy device 112 can have a radially outermost dimension that is greater than that of the core member 114. For example, the thrombectomy device 112 can have a radially outermost dimension sized and configured to permit the thrombectomy device 112 to come into contact with the vessel wall at the treatment site.
In various examples, the thrombectomy device 112 can include one or more radiopaque markers 113 to facilitate visualization under fluoroscopy. In some implementations, providing a plurality of radiopaque markers 113 allows a clinician to determine visually the thrombectomy device 112 is expanded radially when deployed within a blood vessel. For example, by arranging radiopaque markers 113 along various struts, wires, or other structures within the thrombectomy device 112, the individual radiopaque markers 113 may be radially closer together when the thrombectomy device 112 is in its low-profile, constrained state, and the individual radiopaque markers 113 may be radially separated from one another when the thrombectomy device 112 assumes the expanded state. In some examples, the radiopaque markers 113 can be disposed at a distal end portion of the thrombectomy device 112. The radiopaque markers 113 can include marker bands, coils, or other structures made of radiopaque material such as platinum, platinum-iridium, gold, or other suitable material.
The thrombectomy device 112 can have a low-profile, constrained or compressed configuration (not shown in
In some embodiments, the thrombectomy device 112 may comprise an open cell framework or body and a coupling region extending proximally from the body. In some embodiments, a distal portion 115 of the thrombectomy device 112 can be generally tubular (e.g., cylindrical), and the 117 proximal portion of the thrombectomy device 112 tapers proximally to the connection point 118. The proximal taper to the coupling region can permit a small-diameter coupling region to serve as an attachment point for the thrombectomy device 112 even though a distal portion of the thrombectomy device 112 has a significantly larger diameter than the coupling region. Additionally or alternatively, the proximal taper can facilitate resheathing of the thrombectomy device 112, such as by proximally retracting the thrombectomy device 112 into a surrounding catheter. In some embodiments, the thrombectomy device 112 is a mesh structure formed of a superelastic material (e.g., Nitinol) or other resilient or self-expanding material configured to self-expand when released from the microcatheter 116. For example, in some embodiments the thrombectomy device 112 may be a stent and/or stentriever, such as Medtronic's Solitaire™ Revascularization Device, Stryker Neurovascular's Trevo® ProVue™ Stentriever, or other suitable devices. In other embodiments, the thrombectomy device 112 may include a plurality of braided filaments. Examples of a suitable expandable member 210 include any of those disclosed in U.S. Pat. No. 7,300,458, filed Nov. 5, 2007, U.S. Pat. No. 8,940,003, filed Nov. 22, 2010, U.S. Pat. No. 9,039,749, filed Oct. 1, 2010, and U.S. Pat. No. 8,066,757, filed Dec. 28, 2010, each of which is incorporated by reference herein in its entirety.
In some embodiments, some or all of the thrombectomy device 112 is formed by drawn-filled tube (“DFT”) wires having a radiopaque core (e.g., platinum, tantalum, gold, tungsten, etc.) surrounded by a superelastic material (e.g., Nitinol, a cobalt-chromium alloy, etc.). The radiopaque core may comprise about 5% to about 50% (e.g., 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%) of the total-cross-sectional area of the individual wires.
With continued reference to
The delivery catheter 122 also defines a delivery lumen 123 which is sized and configured to receive the thrombectomy assembly 110 therein. For instance, the delivery lumen 123 can have a lumen diameter that is greater than an outer diameter of the microcatheter 116. The thrombectomy device 112 can be configured to be received within the delivery lumen 123, for example while in an at least partially constrained, low-profile configuration. In the illustrated example, the proximal taper at the proximal portion 117 of the thrombectomy device 112 can facilitate the collapse and resheathing of the thrombectomy device 112 within the delivery catheter lumen 123. For instance, the delivery catheter 122 can be introduced into the anatomy over the proximal end of the core member 114 of the thrombectomy device 112, and the delivery catheter 122 can then be distally advanced to the treatment site. As the delivery catheter 122 is distally advanced relative to the thrombectomy device 112 (and/or the thrombectomy device 112 is proximally retracted relative to the delivery catheter 122), a distal end 125 of the delivery catheter 122 contacts the proximal portion 117 of the thrombectomy device 112. As the distal end 125 of the delivery catheter 122 continues to be advanced distally, the thrombectomy device 112 is moved into the lumen 123 of the delivery catheter 122 and assumes a low-profile, constrained configuration.
The expandable member 124 can take the form of a compliant, resilient member mounted to an exterior surface 127 of the delivery catheter 122, for example extending circumferentially around the exterior surface 127 of the delivery catheter 122. In the illustrated example, the expandable member 124 is a generally cylindrical body with tapering proximal and distal portions 129a and 129b. However, the particular shape and configuration of the expandable member 124 can vary, and may assume any suitable form. The length, outermost diameter in the expanded state, and/or shape of the expandable member 124 can be selected depending on the anatomy of the treatment site (e.g. vessel diameter, length of lesion, etc.). In some instances, the expandable member 124 can be a balloon that includes one or more cutting or scoring elements (e.g., blades, wires, etc.) disposed on the balloon surface to enhance displacement of plaque at the treatment site. Additionally or alternatively, the expandable member 124 can include or have disposed thereon one or more liners, coatings, therapeutic agents (e.g., antithrombogenic coatings or drugs, antirestenotic coatings or drugs), etc.
In use, the expandable member 124 can be selectively expanded at a treatment site (e.g., a stenotic region of a blood vessel) to restore patency. The radially outward force of the expandable member 124 can be sufficient to dislodge and/or compress plaque or other buildup at the vessel site, such that after removal of the expandable member 124, the blood vessel lumen is wider than before the intervention. In some examples, the expandable member 124 can be or include a permanent implant, such as a tubular stent. For instance, a tubular stent can be mounted over a balloon and retained in a compressed configuration until the balloon is expanded (e.g., via inflation via delivery of saline through inflation lumen 126), at which point the balloon expansion forces the stent into an expanded state and into apposition with the vessel wall. The stent (or other suitable implant) can remain in the expanded state and in apposition with the vessel wall even after the balloon is collapsed (e.g., by withdrawing saline from the balloon via the inflation lumen 126). In various examples, the stent can be a tubular mesh formed of a laser-cut tube or sheet, braided wires or filaments, combinations thereof, or any other suitable technique. The length, outermost diameter in the expanded state, radially outward force, and/or shape of such a tubular stent can be selected depending on the anatomy of the treatment site (e.g. vessel diameter, length of lesion, etc.).
In operation, the thrombectomy assembly 110 may first be advanced intravascularly to the treatment site, for instance with the thrombectomy device 112 radially constrained within a surrounding microcatheter. The thrombectomy device 112 can then be deployed (e.g., by proximally retracting the microcatheter) such that it expands into apposition with the vessel wall. This expansion may result in improvement or restoration of blood flow through the treatment site. However, if retraction of the thrombectomy device 112 causes blood flow to again become impeded and/or no thrombus material is removed with retraction of the thrombectomy device 112, this can indicate that the stenosis is due to ICAD rather than a thrombus. In such a scenario, the clinician may leave the thrombectomy device 112 in position at or near the treatment site (optionally re-positioning the thrombectomy device 112 so that it is in an expanded configuration at the stenosis, thereby permitting blood flow therethrough). The delivery catheter assembly 120 can then be slidably advanced in a distal direction over the core member 114 of the thrombectomy assembly 110 until the expandable member 124 carried by the delivery catheter 122 is positioned at or adjacent the treatment site. In this approach, the core member 114 of the thrombectomy assembly 110 effectively serves as a guidewire for distal advancement of the delivery catheter assembly 120 to the treatment site. As a result of this distal advancement of the delivery catheter 122 over the thrombectomy device 112, the thrombectomy device 112 can be urged into a low-profile, radially constrained state within the lumen of the delivery catheter 122. The expandable member 124 can then be deployed (i.e., radially expanded into apposition with the vessel wall at the stenotic region), thereby increasing patency of the blood vessel. Finally, the delivery catheter assembly 120 and the thrombectomy assembly 110 can each be removed by proximally retracting these assemblies and withdrawing them from the body.
In some implementations, the thrombectomy assembly 110 can initially be slidably disposed within the lumen 123 of the delivery catheter 122 of the delivery catheter assembly 120. The system 100 can then be advanced to an intravascular treatment site (e.g., a thrombus, a lesion, etc.). The treatment system 100 enables a clinician to perform one or both of a mechanical thrombectomy procedure (by deploying the thrombectomy device 112) and an angioplasty procedure (by deploying the expandable member 124). This can be particularly beneficial in instances in which a clinician is unable to definitively determine whether reduced blood flow observed in a patient is due to a thrombus or atherosclerosis. Example methods of using the treatment system 100 are described in more detail below.
As noted previously, in some instances a clinician may observe occluded blood flow downstream of the treatment site, and yet be unable to determine whether the treatment site is a lesion (e.g., a stenotic region of a blood vessel) or an occluded portion of a vessel due to a thrombus, as these two cases may be difficult to distinguish under conventional visualization and diagnostic techniques. Using the treatment system 100 of the present technology, a clinician may first attempt a thrombectomy procedure to remove a blood clot (if present). If the thrombectomy procedure is unsuccessful (e.g., blood flow is not improved or restored after one or more passes of the thrombectomy device 112 through the treatment site), the clinician may proceed with an angioplasty procedure using the expandable member 124. If, however, the thrombectomy procedure is successful (e.g., blood flow is improved after one or more passes of the thrombectomy device 112, indicating that a blood clot has been successfully removed from the treatment site), then the clinician may retract the treatment system 100 from the treatment site without deploying the expandable member 124.
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Although many of the embodiments are described herein with respect to devices, systems, and methods for treating a cerebral or intracranial embolism, other applications and other embodiments in addition to those described herein are within the scope of the technology. For example, the systems and methods of the present technology may be used to remove emboli from body lumens other than blood vessels (e.g., the digestive tract, etc.) and/or may be used to remove emboli from blood vessels outside of the brain (e.g., pulmonary, abdominal, cervical, or thoracic blood vessels, or peripheral blood vessels including those within the legs or arms, etc.). In addition, the systems and methods of the present technology may be used to remove luminal obstructions other than clot material (e.g., plaque, resected tissue, foreign material, kidney stones, etc.).
This disclosure is not intended to be exhaustive or to limit the present technology to the precise forms disclosed herein. Although specific embodiments are disclosed herein for illustrative purposes, various equivalent modifications are possible without deviating from the present technology, as those of ordinary skill in the relevant art will recognize. In some cases, well-known structures and functions have not been shown and/or described in detail to avoid unnecessarily obscuring the description of the embodiments of the present technology. Although steps of methods may be presented herein in a particular order, in alternative embodiments the steps may have another suitable order. Similarly, certain aspects of the present technology disclosed in the context of particular embodiments can be combined or eliminated in other embodiments. Furthermore, while advantages associated with certain embodiments may have been disclosed in the context of those embodiments, other embodiments can also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages or other advantages disclosed herein to fall within the scope of the present technology. Accordingly, this disclosure and associated technology can encompass other embodiments not expressly shown and/or described herein.
Throughout this disclosure, the singular terms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. Similarly, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the terms “comprising” and the like are used throughout this disclosure to mean including at least the recited feature(s) such that any greater number of the same feature(s) and/or one or more additional types of features are not precluded. Directional terms, such as “upper,” “lower,” “front,” “back,” “vertical,” and “horizontal,” may be used herein to express and clarify the relationship between various elements. It should be understood that such terms do not denote absolute orientation. Reference herein to “one embodiment,” “an embodiment,” or similar formulations means that a particular feature, structure, operation, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present technology. Thus, the appearances of such phrases or formulations herein are not necessarily all referring to the same embodiment. Furthermore, various particular features, structures, operations, or characteristics may be combined in any suitable manner in one or more embodiments.
