Aspiration catheter with an expandable distal tip - Patents.com

Abstract

The aspiration catheter includes a catheter body having a proximal end, a distal end, and an aspiration lumen therebetween. The distal section, constituting the expandable distal tip of the aspiration catheter, includes a membrane and an expandable support structure, such as a scaffold, configured to radially expand the expandable distal tip. The expandable support structure may include support elements and other features that, in the expanded configuration, increase resistance to collapse of the expandable membrane under vacuum or negative pressure applied to aspirate a blood clot through the aspiration lumen.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent No. 63 / 324,540, filed March 28, 2022 (Attorney Docket No. 32016-730.101), U.S. Provisional Patent No. 63 / 327,326, filed April 4, 2022 (Attorney Docket No. 32016-730.102), and U.S. Provisional Patent No. 63 / 487,773, filed March 1, 2023 (Attorney Docket No. 32016-730.103), the entire contents of each of which are incorporated herein by reference.

[0002] FIELD OF THE DISCLOSURE This application relates generally to medical devices and methods for their use. More specifically, the present invention relates to an apparatus and method for removing blood clots from the brain and other vasculature of a patient. [Background technology]

[0003] Every year, millions of people around the world suffer from strokes caused by blood clots in the brain. If not fatal, these clots can lead to serious and permanent disabilities. Until recently, the only means of treating patients with symptoms of occlusive stroke was medicine, where tissue plasminogen activator (tPA) is given into the patient's veins to dissolve the clot and restore blood flow in the brain. However, because vascular thrombi (blood clots) tend to become more fibrous and / or hard over time, the effective time window for tPA is only a few hours after the clot is initially formed. Given the time involved in recognizing that an individual may be having a stroke, transporting them to the hospital, performing a diagnosis, and applying treatment, many patients' clots are mature enough not to respond to tPA, and thus, perhaps two-thirds or more of stroke victims have not benefited significantly from pharmaceutical treatment.

[0004] Advances in medical technology have led to the development of a variety of mechanical thrombectomy techniques in which blood clots are physically extracted from the brain. Mechanical thrombectomy has a major advantage over pharmaceutical treatments in that it can remove blood clots hours after the effective time frame for pharmaceutical treatment has elapsed and still provide benefit to the patient.

[0005] There are two main approaches to mechanical thrombectomy, which may be used independently or in combination with each other depending on patient characteristics and physician preference. The first is to use a catheter to apply a vacuum to the clot in a technique known as direct aspiration. The second is to use a stent retriever to capture and physically extract the thrombus, optionally in combination with applying a vacuum to the clot through a separate aspiration catheter.

[0006] Both mechanical thrombectomy approaches have their limitations. Stent retrievers are small and flexible enough to access, engage and capture most clots, but their ability to latch onto and remove clots varies and has limitations. In some cases, only a portion of the clot may be removed and debris from the procedure may be released downstream and cause secondary occlusion. Stent retrievers can also induce trauma to the vessel as they are typically pulled proximally in the expanded configuration, pulling the clot with them, potentially causing trauma to the vessel. The retriever struts scrape the endothelium from the vessel wall, creating an area more susceptible to future occlusion. Procedure time is also an issue with stent retrievers, in addition to delivery and extraction time, as they typically require significant time to settle and anchor into the clot before an initial removal attempt can be made. In the environment of blood-deprived brain tissue, differences in procedure times have highly clinically significant effects on successful outcome.

[0007] The effectiveness of an aspiration catheter depends on the catheter's ability to aspirate the clot through the catheter's lumen suction, and varies depending on the type, size, location of the clot, and the catheter lumen inner diameter through which the clot is extracted. Although larger inner diameter aspiration catheters are desired to reliably and consistently extract clots, at least some of the following continue to hinder such desirable designs: reduced catheter flexibility, inability to reach the desired anatomy and extract the clot, inability to resist collapse under vacuum, and / or inability of such catheters to access the vessel using current accessory access devices. Current aspiration catheters are limited in diameter by the size of the accessory devices, e.g., hemostatic valves, introducers, and guide membranes / catheters, used by physicians to introduce the aspiration catheter into the anatomy, and are also limited by their ability to navigate and reach the clot location. As a result, today, many aspiration catheters for neurovascular occlusive stroke, for example, typically have an inner diameter of about 0.072 inches. Because most blood clots tend to be significantly larger than the aspiration catheter size, the small size of conventional aspiration catheters presents challenges for successful aspiration due to their inability to aspirate the clot completely or at all upon the first vacuum attempt and without damaging or fragmenting the clot.

[0008] To improve aspiration power and still be able to fit within the access device, some neurovascular occlusion clot aspiration catheters for retrieving clots have been developed with larger lumen diameters, e.g., 0.088 inch aspiration catheters. However, these catheters tend to be bulkier and less deliverable, compromising their ability to reach many clot locations, and / or take longer to reach the clot location.

[0009] Due to their bulkiness, current aspiration catheters often have limited ability to navigate the tortuous anatomy of the brain and reach common target occluded compartments. Such catheters have very low success in reaching more distal clots due to the bulky size of these catheters and the highly tortuous neurovascular anatomy. Smaller aspiration catheters that are more deliverable and / or specifically designed to access more distal clots often fail to extract the clot due to lack of sufficient aspiration force at the tip due to small tip area and / or because the aspiration lumen of the smaller catheter is too small / narrow to absorb or extract the clot.

[0010] To improve deliverability and fit within accessory devices while maintaining the ability to retrieve larger clots, many clot aspiration catheters have expandable distal tips that provide a larger distal opening and a body of reduced size. While generally an improvement, such expandable tips can collapse when negative pressure (vacuum) is applied to retract the clot, thereby compromising their ability to extract the clot.

[0011] To reduce the risk of collapse, some expandable tips are reinforced with expandable metal and other scaffolding, but even with such reinforcing scaffolding, the expandable section of the aspiration catheter can still substantially deform or collapse in response to applied negative pressure (vacuum) in the expanded configuration and / or become more rigid, thereby compromising its deliverability and / or being susceptible to deformation or kinking when advanced into the anatomy in the delivery configuration, compromising the integrity of the aspiration lumen.

[0012] What is needed is a device that, in a delivery configuration, is flexible to improve deliverability thereby being able to reach clots in clot-containing anatomy such as the brain, in proximal and distal neural anatomy or other vascular anatomy; a device that is able to remove clots without fragmenting or substantially fragmenting the clot; a device that is able to remove clots without causing secondary occlusion; a device that is able to reliably remove clots without requiring the use of a stent retriever or other auxiliary device; a device that is able to reach the occlusion and retrieve the clot quickly; a device that does not scrape the vessel wall or otherwise induce trauma at any time during the procedure; a device that removes the clot during the first aspiration attempt; the device is capable of successfully retrieving a blood clot from a blood vessel, a device that can capture fragments broken off from the original clot, a device that, in an expanded configuration, resists deformation under vacuum and substantially maintains its aspiration lumen configuration in the expanded configuration when aspirating a clot, and / or a device that, in an expanded configuration, resists collapse even when exposed to high vacuum pressures during aspiration of a clot, a device that, in an as-delivered configuration, resists deformation or kinking when navigating vascular anatomy, a device that is collapsible to a smaller configuration after being expanded to an expanded configuration, and / or a device that has an expandable distal tip aspiration lumen, where the distal tip aspiration lumen is configured to maximize lumen area or configuration in the expanded configuration. The present invention will address at least some of these needs.

[0013] Related patents and applications include US 2022 / 0125450 and 18 / 156,921, which are commonly owned with this application and are incorporated by reference in their entireties. Other related patents and patent publications include US2015 / 0359547, WO2021 / 016213, US8858497, US2019 / 0328411, US8075510, US2018 / 235644, US2017 / 333060, US2011 / 152920, US2010 / 174290, US2011 / 160761, US2019 / 0381221, US2020 / 0121334, WO2019 / 115809, WO20 This includes US2019 / 212984, WO2018 / 132387, WO2016 / 113047, WO2020 / 079082, WO2020 / 099386, WO2017 / 074721, US2015 / 0305756, US2017 / 0265878, US2018 / 0193043, US10,231,751, US10,500,047, US2021 / 0153883, US10,792,056, and US2007 / 005103. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] US Patent Application Publication No. 2022 / 0125450 [Patent Document 2] U.S. Patent No. 18 / 156,921 Summary of the Invention [Means for solving the problem]

[0015] In a first aspect, the present invention provides an aspiration catheter, for example, but not limited to, a cerebral aspiration catheter, a coronary artery aspiration catheter, an arterial aspiration catheter, or a venous aspiration catheter, comprising a tubular catheter body having a proximal end, a distal end, and an aspiration lumen extending therebetween. The aspiration catheter has an expandable distal tip with a central passageway (or passageway) that is continuous with the aspiration lumen of the tubular catheter body. An expandable support structure is attached to, embedded within, or otherwise coupled to the expandable distal tip of the tubular catheter body. In some cases, the expandable support structure may be attached to the exterior or interior surface of the expandable membrane, but more frequently will be embedded or laminated within the expandable membrane, e.g., a polymeric membrane comprising one, two, three, or more layers and made of one, two, three, or more polymeric or other materials.

[0016] The phrase "distal tip" as used herein and in the claims refers to a length or region at the distal end of the aspiration catheter. The distal tip will typically be constructed differently than the proximal region or shaft of the aspiration catheter. In particular, the distal tip will typically be configured to expand from a small diameter, or from a low profile configuration, or from an as-delivered configuration, to a larger diameter, or from a larger configuration, or from an expanded configuration, or from a deployed configuration, or from an enhanced extraction configuration, which has a greater clot suction or clot extraction force when a vacuum is applied to the proximal end of the aspiration catheter and the distal tip engages a clot, and the expanded (or deployed) configuration of the distal tip remains substantially the same (or remains substantially expanded or deployed) when the vacuum is applied, thereby resisting collapse, and is typically balloon expandable, but sometimes self-expanding. In contrast, the proximal region or shaft will typically have a fixed diameter along its length. The fixed diameter of the proximal region or shaft may be constant or may vary along its length. The distal tip may be in a first clot extraction configuration in the delivery configuration, while the expanded configuration may be in a second clot extraction configuration, the second clot extraction configuration having a greater extraction force than the first clot extraction configuration. In other examples, the expanded configuration may be a clot extraction configuration or may be a preferred clot extraction configuration, typically having an improved clot extraction force. The distal tip typically terminates at the distal end of the aspiration catheter.

[0017] The support structure, typically in the form of a scaffold, is configured to allow radial expansion of the expandable membrane by application of a radially outward expansion, typically using a balloon or other expandable member, located within the support structure, and is configured to enhance the collapse resistance of the expandable membrane, i.e., resist or prevent collapse of the expandable membrane or prevent a reduction in the luminal configuration of the expandable membrane, after expansion of the expandable support scaffold to an expanded configuration when a distal tip is engaged with (or blocked or plugged with) a blood clot and a vacuum is applied through the suction lumen, or the support scaffold substantially maintains the expanded luminal configuration of the expandable membrane when a vacuum is applied to the proximal end of the suction lumen while engaged with a blood clot.

[0018] The support structure typically comprises a plurality of radially expandable rings arranged along a longitudinal axis with gaps therebetween (forming circumferential gaps between adjacent rings). The radially expandable rings typically comprise circular, square, rectangular, oval, spiral, or other looped ring elements configured to inelastically stretch (along their curved length) and allow circumferential expansion of the distal tip. Exemplary ring elements can be formed as serpentine, zigzag rings, boxes (square or rectangular), diamonds, or other patterns with bends that inelastically open in response to a radially outward force provided by a balloon or other expandable deployment member or structure. Exemplary rings may be open cell designs, closed cell designs, combinations of open and closed cell designs, or others. Exemplary ring designs may be formed from a tubular body, bent wire, a patterned sheet wound into a tubular shape, or printed, or others.

[0019] Exemplary open cell support structures may include serpentine and zigzag ring patterns with struts joined by crowns, the crowns having "bends" that open non-elastically to allow radial and circumferential ring expansion. All circular or circumferential rings may have an even or odd number of crowns and struts, but each side or face of the ring may have an even or odd number of crowns. Each ring (including the end rings) preferably has at least 14, 17, 12, 26, 30, 32, 34, 38, 40, 42, 60, 80, 100, 120, 140, 161, 160, 180, 200, or more crowns as counted on both sides / faces of the ring. For example, when a ring is referred to as having 14 crowns, the total number of crowns when counting both sides or faces of the ring is 14. Higher crown counts, such as 60, 80, 100, 120, 1400, 1600, 180, 200, and 400 and greater, are preferred when the support structure does not include additional support elements, or when the support structure cells in a ring, or cells in multiple rings, or cells in each ring, include fewer support elements, or at least some but not all support elements, as described below. Fewer crown counts, such as 14, 22, 26, 30, 32, 34, 38, 40, 42, 48, 60, and 80, are usually sufficient when the support structure includes at least some or a substantial number of support elements per ring, per at least some adjacent rings, or per each ring at the expandable tip. The number of crowns per ring, or per at least some adjacent rings, or per ring along the length of the expandable support structure is configured to allow the expandable support structure to expand to an expanded configuration.

[0020] It has been found that both (1) a greater number of crowns or other bends in the absence of a support element and (2) a fewer number of crowns in combination with a support element will improve the circularity of the rings in the distal tip and maximize the available aspiration lumen area in both the delivery and expanded configurations. The phrase "number of crowns or bends per ring" refers to the total number of crowns or bends as counted in a single 360° turn about each ring. The number "number of crowns or bends per ring" will usually be constant for each ring in an open cell support structure, but in some cases the number may vary from ring to ring. The improved circularity of the distal tip (expandable support structure and expandable membrane) in the expanded configuration can increase the aspiration lumen area, increase the vacuum force, and resist lumen collapse and deformation when a vacuum is applied to the proximal end of the aspiration lumen and the distal tip engages a clot (or the distal tip is blocked or plugged with a clot or other material). Additionally, the enhanced circularity resists deformation and / or kinking of the expandable distal tip in the delivery configuration when the catheter is advanced into the vasculature. Maximizing ring circularity may be further enhanced by having a small cell period and / or a small cell amplitude. In a preferred embodiment, the expandable support structure comprises a plurality of rings, at least some of the rings, and preferably substantially all of the rings, have multiple crowns, small cell periods, and small cell amplitudes, and are configured to have enhanced circumferential circularity.

[0021] For example, in a preferred ring pattern, e.g., a serpentine pattern, comprising struts joined by crowns, the ratio of (1) the number of bends, e.g., crowns, i.e., crowns per ring, to (2) the circumference (perimeter) of the ring measured in millimeters (mm) is typically at least 3 crowns or bends per mm of circumferential length, frequently at least 4 crowns or bends per mm of circumferential length, usually in the range of 3 to 18 crowns or bends per mm of circumferential length, typically 4 to 15 crowns or bends per mm of circumferential length, and most preferably in the range of 4 to 12 crowns or bends per mm of circumferential length. An increased number of crowns or bends per circumference (or in some cases in the majority of rings, or in other cases in multiple rings) or a high ratio of crowns or bends in each ring improves the circularity of the distal tip (including the expandable support structure and expandable membrane) in the expanded configuration, increases the aspiration lumen area, or maximizes the lumen area, improves vacuum force, and resists collapse of the distal tip when vacuum is applied to the proximal end of the aspiration lumen and the distal tip engages a clot (or is blocked by a clot or other material). Additionally, having a small cell period further improves circularity. Additionally, having a small cell amplitude may further improve circularity.

[0022] For example, in embodiments with a support structure that includes a support element, 40 crowns per ring in a 2 mm outer diameter expandable tip at delivery will typically be sufficient to maintain circularity after expansion, while 60, 80, 100, or more crowns per ring may be required to provide equivalent support using a support structure that does not include a support element. Thus, for example, the number of crowns per ring in a support structure at delivery with a 2 mm outer diameter that includes a support element will typically range from 30 to 75, preferably 40 to 75, more preferably 50 to 60. The range for rings without a support structure will be 60 to 150, preferably 70 to 120, more preferably 100 to 120. For embodiments including support elements, the ratio of the number of crowns to the circumference in mm will range from 3 to 10, preferably from 4 to 9, more preferably from 4.5 to 8, most preferably from 5 to 7, while for embodiments without support elements, the ratio of the number of crowns to the circumference (measured in mm) will range from 5 to 18, preferably from 6 to 12, more preferably from 8 to 12, most preferably from 10 to 12.

[0023] Exemplary closed cell support structures may comprise "box" structures joined end-to-end by links in a circular, spiral, or other pattern. Typically, the boxes are joined by circumferential links to form circular rings, which are in turn joined by axial links to form a support scaffold or other support structure. Alternatively, the circumferential links may be arranged in a spiral or spiral pattern, preferably forming a continuous series of rings without additional axial links or attachment points.

[0024] A box will typically be square, diamond, or rectangular, but the box may have any closed polygonal structure, including multiple straight (or sometimes curved) sides joined by bends. In some cases, circular and oval closed shapes may also be considered boxes within the scope of the invention. Such a box structure would be configured to stretch (expand) circumferentially when a radial opening force is applied to the inside of the support structure within the distal tip of the aspiration catheter.

[0025] In preferred embodiments, the expandable distal tip with the expandable support structure has an outer diameter of about 1 mm, 2 mm, 3 mm, 4 mm, or about 5 mm in the delivery configuration, or the expandable distal tip with the expandable support structure has an outer diameter ranging from 1 mm to 5 mm in the delivery configuration. In other embodiments, the distal tip with the expandable support structure has an outer diameter of about 7 mm, 8 mm, 9 mm, or about 10 mm in the delivery configuration. Typically, the distal tip has a cylindrical shape in the delivery configuration. In some other embodiments, the distal tip may have other shapes in the delivery configuration, such as a funnel, cone, oval, elliptical, or other shapes. In yet another embodiment where the distal tip comprises an expandable support structure, the distal tip has a cylindrical, oval, elliptical, conical, funnel, or other shape in the expanded configuration, and the distal tip outer diameter ranges from 2 mm to 10 mm, preferably from 3 mm to 8 mm, and more preferably from 3 mm to 7 mm in the expanded configuration. The outer diameter of the distal tip may vary along or about the circumference of the distal tip, or may be fixed or constant along or about the circumference of the distal tip.

[0026] In some cases, the scaffold or other support structure will also include support elements that will help support spaces that open within the support structure as it expands. For example, in a support structure that includes a serpentine ring with crowns and struts, as the rings expand, the struts will spread apart, leaving unsupported spaces or gaps between them. The gaps between adjacent rings will also be unsupported spaces both before and after the support structure is radially expanded. The membrane will lack support within those gaps, and both the circularity and / or crush strength (crush resistance) of the expanded distal tip will be reduced. In addition, such unsupported areas of the membrane will cause an increased risk of impaction (crushing or partial collapse of the membrane and / or expandable support structure) when a clot is engaged, particularly when the open distal tip is partially or totally occluded with a clot, or when negative pressure is applied to the aspiration lumen of the catheter when the expandable tip is delivered to the vasculature in the delivery configuration.

[0027] The support elements of the present invention will be configured to fill much of the open space within the rings. In contrast, the spaces or gaps between axially adjacent rings will preferably be free of support elements (although axial connections and other portions of support structure will typically be present in some embodiments, while in other embodiments the spaces or gaps between axially adjacent rings may be free of any support elements or attachment points and free of any portions of support structure). The spaces between adjacent rings should have a minimal number of support structures, if any, to enhance flexibility, especially in the unexpanded delivery configuration.

[0028] In one embodiment, in the unexpanded delivery configuration, the support elements of the present invention will cover or fill 50%-98%, preferably 65%-95%, more preferably 75%-95%, and most preferably 80%-95% of the unsupported area in each ring. In contrast, in the expanded configuration (i.e., after deployment within the vessel), the support elements of the present invention will cover or fill 10%-85%, preferably 15%-85%, more preferably 20%-85%, and more preferably 40%-85% of the unsupported area in each ring.

[0029] Preferred support elements are "cantilevered" from the rings and are configured to fill or support openings or gaps within the "axial width" of the rings while typically remaining outside the gaps and spaces between adjacent rings to support the distal tip after being radially expanded without significantly reducing the flexibility of the distal tip as it is advanced into the vasculature or while maintaining the flexibility of the distal tip as it is advanced into the vasculature. Exemplary support elements have a base (proximal) end and a free (distal) end. The base end is typically attached to one of the radially expandable rings (e.g., a ring structural element, e.g., a crown or strut), and the free end is often oriented toward the gap between adjacent rings and typically does not extend into the gap between adjacent rings in the delivery configuration. In a preferred embodiment, the expandable support structure comprises a plurality of support elements within each ring, each having a width, length, and thickness sufficient to support an unsupported space (or region) within the ring and prevent collapse or intrusion (partial collapse) of the unsupported region when a vacuum is applied to extract a clot engaged to the distal end of the aspiration catheter. In another embodiment, the expandable support structure comprises a plurality of circumferential rings, at least some of the rings comprising a plurality of support elements configured to resist collapse of the unsupported region or resist intrusion when a vacuum is applied to a proximal end and a clot is engaged to the distal end of the aspiration catheter. In yet another embodiment, the expandable support structure comprises a plurality of circumferential rings, at least some of the rings comprising at least some support elements configured to resist collapse of the unsupported region or resist intrusion when a vacuum is applied to a proximal end and a clot is engaged to the distal end of the aspiration catheter.

[0030] In some cases, the support elements may extend into the adjacent gaps between adjacent rings even prior to radial expansion of the distal tip, but preferably most or all of the support elements are configured to be recessed (or confined) within the axial width of the rings (or within the amplitude of the ring cells) prior to ring expansion, and will extend, protrude, or emerge further toward or into the adjacent gaps between adjacent rings as the distal tip is radially expanded (or only after or during radial expansion of the distal tip). It has been found that the presence of support structures in the gaps between adjacent rings prior to distal tip expansion will reduce tip flexibility during advancement into the vasculature prior to distal tip deployment. Such loss of flexibility is undesirable.

[0031] The use of such "cantilevered" support elements is for "support of the unsupported regions or gaps located within the ring axial width" that are deployed to improve support of the expandable membrane after deployment of the distal tip without increasing the stiffness of the distal tip during delivery (introduction and advancement) of the aspiration catheter into and through the patient's vasculature. The use of the support elements also allows for increased expansion of the distal tip while resisting collapse when a vacuum is applied to the proximal end of the aspiration lumen (thus increasing the available aspiration lumen diameter). In another example, the support elements deploy (or protrude or extend further) toward or into the gap between two adjacent rings as the distal tip is expanded (or after distal tip expansion) to improve support of the expandable membrane after deployment of the distal tip without increasing the stiffness of the distal tip during delivery (introduction and advancement) of the aspiration catheter into and through the patient's vasculature.

[0032] The support elements may have a variety of shapes and configurations, e.g., I, T, U, M, Z, curved, straight, or other shapes and configurations, and preferably support or improve support of the unsupported section of the expandable membrane without increasing the stiffness of the distal tip. The free end may have a flat, rounded, spherical, or other shape. The width of the support element may be the same or different along the length of the support element. The support element may be tapered, either increasing or decreasing in width in the direction from the attached proximal end to the free distal end.

[0033] In preferred cases, the dimensions of the support elements will preferably be selected to fill or occupy much of the unfilled space or gap within any given ring in the support structure (but typically not between adjacent rings) that may exist prior to expansion. For example, gaps between struts joined by crowns on the rings may be filled with support elements cantilevered from the inner curve of the crowns as illustrated in many embodiments herein. The cantilevered support elements can be patterned to fill virtually the entire space between the struts, leaving only cuts or very small separation lines between them. By maximizing the area of ​​the support elements prior to expansion, coverage of the gaps created after expansion is also maximized between the struts after the rings are expanded. In preferred embodiments, the width of the support elements at the attached base end is approximately equal to or greater than the width of the structural element (e.g., strut, crown, or link) relative to where the support element is attached.

[0034] The support element and the expandable support structure are typically formed from the same material, although in some cases they may be formed from different materials or types of materials, for example, (1) one may be formed from a metal and the other from a polymer, or (2) one may be formed from a metal or a polymer and the other from a different metal or a different polymer.

[0035] In another preferred embodiment, the support element is recessed into the space between the structural elements of the rings, e.g., into the space between the struts joined by crowns, such that the distal end of the support element, in the delivery configuration, does not extend substantially beyond the peaks of adjacent crowns or other structural elements into the gap between adjacent rings.

[0036] In particular embodiments, a support element may have one proximal end and one free end, two free distal ends, three free distal ends, or more.

[0037] In another embodiment, the support elements may have two or more proximal ends each attached to one or more structural elements on one ring (the same ring). Such support elements may have one, two, three, or more free distal ends.

[0038] In another embodiment, the support element may be bisected and have at least two proximal ends, each attached to a different structural element on a single ring. The proximal ends of the support elements may be attached to an axially inner or axially outer surface of the ring or of a structural element of the ring that includes a crown, strut, or link.

[0039] In a specific embodiment, the radially expandable ring is arranged within a cylindrical "shell" prior to expansion. The cylindrical shell is an imaginary space having an inner generally cylindrical surface, an outer generally cylindrical surface, and an annular volume therebetween, and the radially expandable ring will be sized and arranged to fit within this space prior to expansion. Typically, the support element will also be configured to fit within this imaginary cylindrical shell prior to expansion of the ring. The cylindrical shell may have a diameter greater than, equal to, or smaller than that of the tubular catheter body prior to expansion.

[0040] In a specific embodiment, the distal tip of the expandable support structure may be configured to expand into a cylindrical shape, a cone shape, or a combination thereof after expansion to the expanded configuration. In a preferred embodiment, the distal tip of the expandable support structure may be configured to expand from a cylindrical configuration to an expanded cylindrical configuration, to an expanded cone-shaped configuration, or to an expanded cone-shaped distal tip configuration when a vacuum is applied to the proximal end of the aspiration lumen to maximize or enhance suction force. In another embodiment, the distal tip of the expandable support structure may be configured to expand from a cylindrical configuration in the delivery configuration to a generally cylindrically shaped configuration after the expandable support structure is expanded into the expandable configuration, the expanded configuration being larger than the delivery configuration, or the expanded configuration being in the range of 1.1 to 4 times larger than the delivery configuration, preferably 1.3 to 3 times larger. In yet another embodiment, the distal tip of the expandable support structure is configured to expand from a cylindrical configuration to an expanded cone-shaped configuration at a proximal section of the distal tip and is continuously connected to the expanded cylindrical configuration distal to the expanded cone-shaped configuration. In yet another configuration, the expanded configuration may be a combination of a long cone-shaped proximal base (usually at least a short cone-shaped portion will be present at the proximal end) and a distal cylindrical portion attached to the proximal end of the shaft. Some specific configurations are illustrated in the figures.

[0041] In specific embodiments, the expandable support structure is configured to expand in response to expansion of a balloon catheter within the expandable support structure. The balloon catheter may be configured to be delivered with an aspiration catheter comprising the expandable support structure at its distal end, typically within the aspiration lumen of the aspiration catheter, such that after the distal end of the distal tip of the aspiration catheter is positioned adjacent to the clot, the balloon catheter is expanded to expand the expandable support structure to an expanded configuration, and then deflated and withdrawn out of the aspiration catheter prior to applying a vacuum to the proximal end of the aspiration catheter to extract the clot. In another embodiment, a balloon catheter is delivered to the distal end of the aspiration catheter after the aspiration catheter has been delivered and positioned adjacent to the clot, and the balloon catheter is advanced through the aspiration catheter until the balloon reaches or reaches the expandable distal tip section, then expanded to expand the distal tip section of the aspiration catheter, then deflated and removed from the aspiration catheter, and a vacuum is applied to the proximal end of the aspiration catheter to remove (extract) the clot. In another embodiment, the dilation catheter has an expandable member at its distal end that is expanded to expand an expandable distal tip comprising an expandable support structure (scaffold) and an expandable membrane, the distal tip being incorporated into or coupled to the distal end of the aspiration catheter, and the expandable member comprising a balloon, scaffold, cage, or other structure that is capable of expanding to expand the expandable support structure from a delivery configuration to an expanded configuration. The expandable member may be a polymer, metal, or other material, and is expandable from an as-delivered, crimped, or contracted configuration to an expanded configuration. The distal tip may be fully expanded along its entire length, but often only a portion of the length of the distal tip may be expanded by a balloon or other expandable member, depending on the patient anatomy or other circumstances. The portion of the distal tip that is expanded can be controlled by adjusting the length of the balloon present in the distal tip during expansion and / or by selecting expansion balloons having different lengths.

[0042] In a preferred embodiment, the expandable support structure at the distal tip of the aspiration catheter is formed from a deformable material, preferably a plastically deformable material. In a preferred embodiment, the expandable support structure is formed from a plastically deformable metal or metal alloy. In a specific embodiment, the expandable support structure is formed from a metallic material, including a stainless steel alloy, a cobalt chromium alloy, a platinum chromium alloy, or other metal or metal alloy.

[0043] The expanded shape of the support structure is typically determined by the shape of the balloon or other expansion structure; i.e., expansion of a cylindrical balloon within a plastically deformable support structure will impart a cylindrical shape to the distal tip, while expansion of a conical balloon will impart a conical shape to the distal tip.

[0044] In some less preferred embodiments, the expandable support structure may be configured to self-expand upon release from a radial constraint. The radial constraint may be positioned across the expandable support structure. In other embodiments, the radial constraint may be positioned within the expandable support structure (inner lumen) and configured to release the expandable support structure in vivo and allow the expandable support structure to expand. The expandable support structure, in one embodiment, is formed from a shape memory material, such as NiTi Nitinol or other shape memory material.

[0045] The support elements may have any one or more of a variety of shapes and attachment locations on the expandable structure. For example, the support elements may extend axially relative to the radially expandable rings toward or into the gaps between adjacent rings. In other examples, the support elements may extend circumferentially relative to the radially expandable rings, typically attached to the outwardly curved surface of the crowns (peaks) and extending circumferentially into the adjacent gaps. In other examples, the support elements may extend axially relative to the radially expandable rings into gaps contained within or bounded by the axial width of the rings, or contained within or bounded by the spaces of or between the structural elements of each ring, typically attached to the curved surface of the crowns. In still other examples, at least some of the support elements may comprise any one or more of linear and / or nonlinear sections and may have an extended tip (forming a contact pad, as discussed later herein) at the free end. In some examples, the support elements may branch into two or more sections in a direction toward the free end. The support elements may have the same or different lengths or widths. In some specific examples, the support elements may have a length equal to or less than the length of the adjacent strut length in the as-delivered configuration. In other examples, the support elements may have a length equal to or less than the ring cell amplitude in the as-delivered configuration, or less than one time the ring cell amplitude in the as-delivered configuration. In yet other examples, the support elements may have a length equal to or less than the length of the ring period in the as-delivered configuration. In other examples, the support elements may have a length greater than the ring cell amplitude only in the expanded configuration.

[0046] In some embodiments, the support element is attached to one or more of the axially inner crown region, the axially outer crown region, the struts, the central strut, or is attached to an axial or circumferential link.

[0047] In some preferred embodiments, at least some of the radially expandable rings comprise a serpentine, zigzag, box, diamond, or other pattern including struts joined by crowns, and at least some of the adjacent rings are joined at one or more locations by axial connections or attachment points, for example, using solder, bonding, or fused crowns on adjacent rings, or as patterned. Alternatively, at least some of the adjacent rings may be joined end-to-end in a helical arrangement without axial connections or attachment points, and preferably the amplitude on at least some of the rings is fixed within each ring. In preferred embodiments, at least two adjacent rings or at least some of the adjacent rings at the expandable support structure distal tip have no more than two connections or no more than two attachment points joining the at least two adjacent rings (or joining the at least some of the adjacent rings). In another embodiment, the expandable support structure comprises a plurality of circumferentially expandable rings including struts joined by crowns, where one or more adjacent rings are axially separated by gaps and are not disconnected, typically the one or more disconnected adjacent rings are held together by an expandable membrane located at the distal end of the distal tip of the aspiration catheter and attached to the one or more adjacent disconnected rings, providing the distal tip with enhanced flexibility in the as-delivery configuration and allowing the one or more rings to expand from the as-delivery configuration to the expanded configuration. In a preferred embodiment, the expandable support structure comprises a plurality of adjacent expandable rings, where along the length of the expandable structure adjacent rings have two or less connection or attachment points joining the adjacent rings, preferably adjacent rings have one connection or attachment point joining the adjacent rings, the length being the entire length of the expandable structure or a section along the axial length of the expandable structure, where the section comprises two or more rings. In a further preferred embodiment, the expandable support structure comprises a plurality of adjacent rings joined end-to-end in a helical arrangement, which in the delivery configuration enhances the flexibility of the aspiration catheter for navigating tortuous anatomy.Adjacent rings, in this embodiment, are not joined by links or attachment points on adjacent rings, and at least some adjacent rings each have a fixed (or constant or identical) ring cell amplitude, and preferably all at least some rings have a fixed (or constant or identical) ring cell amplitude. In this embodiment, at least some rings may be patterned in an open cell pattern, a closed cell pattern, or a combination of open and closed cell patterns along the length of the expandable scaffold.

[0048] Alternatively, in another embodiment, at least some of the adjacent rings in the expandable support structure may be joined end-to-end in a helical arrangement. Such a helical arrangement would typically comprise a "smooth" helix with no additional curves or bends, i.e., curves formed across a conical or cylindrical surface that would be straight if the surface were folded back into a flat surface. In other cases, one, two, three, or more additional bends, curves, or other second-order nonlinearities may be superimposed across the helical rings to enhance the flexibility of the expandable structures, particularly in their crimped or reduced diameter configuration during delivery. Such one, two, three, or more additional bends, curves, or other second-order nonlinearities may be formed from the expandable support structure or the non-expandable structure. In a specific preferred embodiment, the expandable support structure forms a helical coil.

[0049] In other preferred embodiments, the expandable membrane may comprise an elastic membrane or a non-elastic membrane (stretchable membrane). The elastic and / or non-elastic membrane may comprise one or more elastomers, polymeric materials, or other materials. In preferred embodiments, the expandable membrane is a NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft TM596-50A, NeuSoft NEU 455-55A, NeuSoft NEU 455-60A NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG 80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A Tecoflex TT-18095A, Elastollan S 50 A 15SPF Elastollan S 60 A 10W Elastollan S 60 A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane Rx50A, Texin RXT 70A, Chronoflex C 80A-Q, Chronoflex AL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex 00-30, Ecoflex 00-20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, Chronoprene, Chronocene, Chronosil, Polyethylene, e.g., LDPE, HDPE, Ultra HMWPE, or equivalent, Pebax, e.g., Pebax 2533, Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, or equivalent; nylon, e.g., nylon 12, nylon 6 / 6 or nylon 6; polyurethane, e.g., Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMart Ultra TPU72D, a fluoropolymer, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropene), poly(vinylidene fluoride-co-hexafluoropropene), fluorinated ethylene propylene, polychlorotrifluoroethylene ethylene, or the like, or combinations thereof, or other elastomers, polymers, or other materials.

[0050] In one embodiment, the expandable membrane comprises a polymeric elastic membrane, which may have isotropic properties, but in other cases may have anisotropic properties, e.g., the elastic membrane may have higher elasticity in the circumferential or radial direction than in the axial direction.

[0051] In some cases, the expandable membrane may be formed by heat shrinking over or on an expandable support structure, such as a scaffold. In other cases, the expandable membrane may be formed by laminating an expandable support structure, such as a support scaffold, between two or more layers of a polymeric material, such as an elastomeric material, an elastomer on the exterior of the expandable structure and a non-elastic / stretchable polymeric material on the interior surface, a stretchable / non-elastic material on both the exterior and interior surfaces of the expandable structure, or a stretchable material on the exterior surface of the expandable structure and an elastic material on the interior surface. For example, two layers of elastomer, one elastic and one stretchable, two layers, or both stretchable, may be bonded to each other over (squeezing) the expandable support structure, such as a support scaffold, such that there is a seal or bond between the two layers and the two layers are sandwiched, bonded to, and / or adhered to the scaffold or other expandable structure. In another embodiment, the expandable membrane comprises a polymer or other material configured to stretch and / or expand from an as-delivery configuration to an expanded configuration, the material configured to expand from the as-delivery configuration to a larger configuration ranging from 1.1 to 5 times larger than the as-delivery configuration. The expandable membrane has axial, radial, and / or circumferential stiffness and is configured to allow radial flexibility while maintaining axial pushability. The expandable membrane is configured to allow radial expansion of the expandable support structure and / or allow axial movement of the expandable support structure ring as the ring is expanded from the as-delivery configuration to the expanded configuration.

[0052] In a preferred embodiment, the aspiration catheter comprises a tubular catheter body having a proximal end, a distal end, and an aspiration lumen extending therebetween. The aspiration catheter has an expandable distal tip with a central passageway that is continuous with the aspiration lumen of the tubular catheter body, and comprises an expandable support structure, the expandable section being attached to or embedded within an expandable membrane. In one preferred embodiment, the expandable support structure is patterned from a tube, a bent wire, or a wound patterned sheet. The tube, the bent wire, or the wound sheet, in a preferred embodiment, is patterned such that the expandable support structure is expandable from a delivery configuration to an expanded configuration. In certain other preferred embodiments, the aspiration catheter comprises a tubular catheter body having a proximal end, a distal end, and an aspiration lumen extending therebetween. The aspiration catheter has an expandable distal tip with a central passageway that is continuous with the aspiration lumen of the tubular catheter body. The expandable support structure is attached to or embedded within the expandable distal tip of the tubular catheter body. The tubular catheter body may be reinforced with a reinforcing structure proximal to the expandable tip over at least a portion of its length by one or more of a coil, a scaffold, a scaffold with support features, or other means. In some cases, at least a portion of the catheter body reinforcing structure comprises one or more of a coil, a scaffold, or a braid that may be formed continuously with the expandable support scaffold or other expandable support structure of the expandable tip. In preferred embodiments, the reinforcing structure and the expandable scaffold or other expandable support structure are formed from patterned tubes. In other embodiments, the reinforcing structure and the expandable scaffold or other expandable support structure are formed from bent wires. In other cases, the reinforcing structure in the catheter body is formed separately from the support scaffold of the expandable distal tip and then bonded or spliced ​​together by one or more of soldering, fusing, bonding, or weaving the structures together and overlapping them at their interface over a length section.

[0053] In another embodiment, the aspiration catheter comprises a catheter body having a tubular proximal end, a distal end, and an aspiration lumen extending therebetween. The aspiration catheter has an expandable distal end with a central passageway that is continuous with the aspiration lumen of the tubular catheter body, the expandable distal end comprising an expandable support structure attached to or embedded within an expandable membrane. In one specific embodiment, the expandable distal end comprising the expandable support structure has a length ranging from 0.5 mm to 50 cm, preferably ranging from 1 cm to 25 cm, more preferably ranging from 2 cm to 10 cm. In yet another embodiment, the expandable distal end may have a length that spans substantially the length of the aspiration catheter. In a specific embodiment, the expandable distal end may have a length ranging from 50 cm to 150 cm. In a preferred embodiment, the expandable distal end comprises an expandable distal tip, the distal tip comprising a section of the expandable support structure attached to or embedded within an expandable membrane. In some specific embodiments, the expandable distal tip section comprises an expandable distal end section, hi certain other cases, the expandable distal tip is the same as the expandable distal end.

[0054] In other preferred embodiments, at least some of the multiple support elements may have their base ends attached to the struts, respectively. In other preferred embodiments, at least some of the multiple support elements may have their base ends attached to either the inner curved surface or the outer curved surface of the crown, respectively. The support elements may extend or be oriented axially, circumferentially, or at other angles or directions relative to the support scaffold or other expandable support structure, support scaffold ring, or structural elements of the scaffold ring.

[0055] In a second aspect, the present invention provides an aspiration catheter having an alternative expandable support structure design. The alternative aspiration catheter comprises a tubular catheter body having a proximal end, a distal end, and a lumen extending therebetween. The expandable support structure is attached to or incorporated into the distal end or tip of the tubular catheter body and has a central passageway that is continuous with the lumen of the tubular catheter body, the expandable support structure including an expandable membrane and an expandable scaffold or other expandable support structure configured to radially expand the expandable membrane. The expandable membrane is typically elastically expandable and the expandable scaffold or other expandable support structure is typically inelastically expandable, i.e., the scaffold plastically deforms to and maintains an expanded shape and size in response to radial expansion by a balloon or other radial expansion tool. In this manner, the expansion support structure "supports" the membrane in the expanded configuration.

[0056] In other cases, the membrane may be plastically or otherwise inelastically expandable while the support structure is elastic or inelastic, although such embodiments are generally not preferred.

[0057] The expandable support structure may comprise a plurality of radially expandable rings arranged along a longitudinal axis, at least some of which comprise "expandable cells" having bends that can plastically deform to allow radial opening of the rings. The cells may have "open" configurations, e.g., U-shaped cells in serpentine rings and V-shaped cells in zigzag rings, square, rectangular, or other regular or irregular polygonal shapes with one or more missing sides, and ω-shaped cells. Alternatively, the cells may have "closed" configurations, e.g., diamond-shaped, or box-shaped cells in box-enclosed rings, where the box shapes can be rectangular, square, or other regular or irregular polygonal shapes.

[0058] The support elements may be positioned inside or outside the open cells. For example, the base of the cantilevered support element may be attached to the inner curved surface of the crown and positioned between adjacent struts in a U-shaped, V-shaped, or ω-shaped open cell. Alternatively, the base of the cantilevered support element may be attached to the outer curved surface of the crown and extend away from the struts into the gap adjacent the U-shaped, V-shaped, or ω-shaped open cell.

[0059] The support elements may also be positioned on the inside or outside of a box or other closed cell. For example, the base of a cantilevered support element may be attached to the inside surface of the box and protrude into the interior space of the box. Alternatively, the base of a cantilevered support element may be attached to the outside of the box or on a circumferential joint that attaches the box or other closed cells together to form a ring.

[0060] Typically, at least one end of the support elements is attached to the struts or crowns of the radially expandable ring or at least one location on the ring. However, in some cases, at least some of the support elements may not be attached to the support scaffold or other expandable support structure, but are attached or bonded only to the expandable membrane such that they reinforce the V-shaped, ω-shaped, U-shaped, or square / box-shaped spaces between the struts and will improve the resistance of the expandable membrane to collapse under vacuum / negative pressure if the distal tip becomes blocked or plugged with a blood clot or other material.

[0061] In some cases, at least some of the support elements may extend circumferentially from the radially expandable ring into the cell space (V-shaped, ω-shaped, U-shaped, or square / box-shaped space). In a preferred embodiment, at least some of the support elements extend circumferentially from an outer crown region to an adjacent outer crown region in one direction or in two opposing directions. In another preferred embodiment, at least some of the support elements extend circumferentially from a strut to an adjacent strut in one direction or in two opposing directions. In other cases, at least some of the support elements extend axially from the radially expandable ring into and / or beyond the cell space (V-shaped, ω-shaped, U-shaped, or square / box-shaped space). In a preferred embodiment, the support features are configured to shorten when the expandable support structure is expanded to the expanded configuration such that the support feature length is equal to or less than the amplitude of the expandable ring cells, or such that the support features do not extend axially beyond the peaks of the adjacent crowns. In another preferred embodiment, the support features are configured to deploy or protrude further when the expandable support structure is expanded to the expanded configuration to provide improved support to the expandable membrane and to provide the expandable membrane with improved resistance to collapse when a vacuum is applied to the proximal end of the aspiration lumen.

[0062] In a preferred embodiment, the present invention provides an aspiration catheter having an expandable support structure design. The aspiration catheter comprises a tubular catheter body having a proximal end, a distal end, and a lumen extending therebetween. The expandable support structure is attached to or incorporated within the distal end (or distal tip) of the tubular catheter body and has a central passageway continuous with the lumen of the tubular catheter body, the expandable support structure including an expandable membrane and a support scaffold or other expandable support structure configured to radially expand the expandable membrane. The expandable support scaffold or other expandable support structure comprises a plurality of radially expandable rings arranged along a longitudinal axis, at least some of the radially expandable rings including struts joined by crowns and having a serpentine or zigzag or other open pattern forming a V-shaped, ω-shaped, U-shaped, or open square / box-shaped space therebetween. A number of support elements are positioned within the V-shaped, omega-shaped, U-shaped, or square-shaped space and in a delivery configuration and / or expanded configuration support a membrane within the V-shaped, omega-shaped, U-shaped, or open square / box-shaped space, the support scaffold or other expandable support structure resists collapse of the membrane within the space in an expanded membrane and scaffold or other expandable support structure configuration when a vacuum is applied to the proximal end of the aspiration lumen and the distal tip becomes blocked or embolized with a blood clot or other material, and the support scaffold or other expandable support structure is capable of contracting from the expanded configuration to a smaller configuration when the aspiration catheter is withdrawn into a guiding catheter having an inner lumen configuration smaller than the expanded configuration of the support scaffold or other expandable support structure.

[0063] In a preferred embodiment, the present invention provides an aspiration catheter having an expandable support structure design. The aspiration catheter comprises a tubular catheter body having a proximal end, a distal end, and a lumen extending therebetween. The expandable support structure is attached to the distal end (or distal tip) of the tubular catheter body and has a central passageway continuous with the lumen of the tubular catheter body, the expandable support structure including an expandable membrane and a support scaffold configured to radially expand the expandable membrane. The expandable support scaffold includes a plurality of radially expandable rings arranged along a longitudinal axis, at least some of the radially expandable rings including struts joined by crowns and having a serpentine or zigzag or open pattern forming cell spaces therebetween. A number of support elements are positioned within the cell space to support the membrane within the cell space in a delivery configuration and / or expanded configuration, the support elements resist collapse of the membrane within the space in an expanded membrane configuration when a vacuum is applied to the proximal end of the aspiration lumen and the distal tip becomes blocked or embolized with a blood clot or other material, and the support elements allow the expanded support structure to contract from the expanded configuration to a smaller configuration when the aspiration catheter is withdrawn into a guiding catheter having an inner lumen configuration smaller than the expanded configuration of the support structure.

[0064] In a third aspect, the invention provides a method for aspirating a blood clot from a patient's vasculature. The method includes positioning a distal end of an expandable support structure of any of the aspiration catheters as described within the patient's vasculature at or near the region of the clot. The expandable support structure is expanded, typically by balloon expansion (but alternatively by self-expansion), to engage the clot or engage the vessel wall adjacent the region of the clot. Negative pressure (vacuum) is applied to the proximal end of an aspiration lumen in the catheter body, aspirating the clot into the aspiration central passage of the expanded expandable structure.

[0065] In a preferred embodiment, the present invention provides a method for aspirating a blood clot from a patient's vasculature. The method includes positioning a distal tip of an expandable support structure of any of the aspiration catheters as described within the patient's vasculature at or near the blood clot. The expandable support structure is expanded, typically by balloon expansion, but alternatively by self-expansion, to an expanded configuration and engages the blood clot or engages the vessel wall adjacent the clot. A vacuum is applied to the proximal end of a lumen within the catheter body to aspirate the blood clot into a central passage of the expanded expandable structure, and at least a portion of the expandable support structure is optionally contracted from the expanded configuration to a smaller configuration prior to removal from the vasculature.

[0066] In a fourth aspect, the present invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and a lumen extending along a longitudinal axis. The distal tip has a proximal end embedded within or attached to the distal end of the tubular catheter body, and a central passage (aspiration lumen) longitudinally continuous with the lumen of the tubular catheter body. The distal tip is adapted to expand from an as-delivered configuration to a radially expanded configuration or from a radially contracted configuration to a radially expanded configuration in response to a radially outward expansion force applied within the distal tip section, the distal tip comprising an expandable membrane and an expandable support structure, such as a scaffold, the expandable scaffold or other expandable support structure comprising a plurality of rings spaced apart along the longitudinal axis with gaps therebetween. At least some of the rings comprise a malleable metal or metal alloy configured to plastically deform and circumferentially expand the scaffold or other expandable support structure in response to a radially outward expansion force applied from within the distal tip.

[0067] In some cases, the expandable membrane is attached to the inner and / or outer surface of the expandable scaffold or other expandable support structure. In other cases, the expandable scaffold or other expandable support structure is embedded within or in the expandable membrane, which comprises at least two membranes, one attached to the outer surface of the expandable scaffold or other expandable support structure and the other attached to the inner surface of the expandable scaffold or other expandable support structure. In other cases, the aspiration catheter comprises an expandable tip, which comprises an expandable membrane and an expandable support structure, such as a scaffold, which comprises a plurality of rings spaced apart along a longitudinal axis with gaps therebetween and within each of the rings, the rings comprising a structural element comprising struts and crowns. The expandable scaffold or other expandable support structure is embedded within or in an expandable membrane, the expandable membrane comprising at least one membrane that is softened and / or melted over an outer surface of the expandable scaffold or other expandable support structure and / or over an inner surface of the expandable scaffold or other expandable support structure, allowing the expandable membrane to protrude or flow into gaps present in the ring structural elements and between adjacent rings, and adheres to the rings and ring structural elements to provide a unified (integrally) expandable scaffold / membrane system that is expandable from a contracted or as-delivered configuration to a larger expanded configuration. The expandable membrane, in a preferred aspect, covers the exterior and / or interior surfaces of the expandable structure, where the covering comprises one or more of filling, flowing into, or protruding into at least some of the gaps present within each ring of the expandable scaffold or other expandable support structure and gaps present between adjacent rings of the expandable scaffold or other expandable support structure, the flowing membrane sufficiently adheres to the scaffold or other expandable support structure ring structural elements to provide a unified system (integrated system) capable of expanding from a delivery configuration to an expanded configuration as an integrated system.The expandable membrane, in preferred aspects, flows into gaps present between each of the rings in each of the ring structural elements, which comprise struts joined by crowns, and the one or more expandable membranes, in preferred aspects, cover the exterior and / or interior surface of the expandable scaffold or other expandable support structure, cover at least some side surfaces of the expandable scaffold structural element, and preferably cover substantially all side surfaces of the expandable scaffold structural element, and cover substantially all gaps between adjacent rings of the expandable scaffold or other expandable support structure. The expandable scaffold or other expandable support structure, in preferred aspects, comprises an exterior surface, an interior surface, and two side surfaces. In other aspects, the expandable scaffold or other expandable support structure is formed from a bent wire, which comprises an exterior surface and an interior surface.

[0068] In some cases, the scaffold or other expandable support structure has a delivery configuration or a radially contracted (e.g., crimped) delivery configuration and an expanded, deployed configuration. Typically, the radially contracted configuration has a maximum outer diameter in the range of 0.5 mm to 30 mm, usually 1.0 mm to 5 mm, more usually 2 mm to 5 mm, and the radially expanded configuration has a maximum outer diameter in the range of 1 mm to 60 mm, preferably 1.5 mm to 45 mm, more preferably 3 mm to 45 mm.

[0069] In some cases, the distal tip may be configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to a radially outward expansion force applied within at least a portion of the distal tip. In other cases, the distal tip is configured to expand from an initial cylindrical shape to an enlarged conical configuration in response to a radially outward expansion force applied within at least a portion of the distal tip. In preferred embodiments, the enlarged conical configuration terminates at a distal end of the distal tip and provides a maximum surface area for clot extraction.

[0070] In some cases, the tubular catheter body may have a working length from proximal to distal end in the range of 50 cm to 200 cm, an outer diameter in the range of 0.5 mm to 30 mm, and an inner lumen diameter of 0.25 mm to 25 mm.

[0071] In some cases, the distal tip may have a bending resistance in its initial radially contracted or delivered configuration, as measured by a 3-point flexure test (described in more detail below), of less than 1 N, preferably less than 0.5 N, more preferably less than 0.3 N, and most preferably less than 0.2 N. The distal tip may also have a collapse pressure (vacuum) in its radially expanded configuration of 0.5 atm or greater, preferably 0.75 atm or greater, more preferably at about 1 atm, and most preferably greater than 1 atm in its radially expanded configuration, once a vacuum is attached to the proximal end and a blood clot (or embolus) engages and blocks the open distal end of the distal tip. In other embodiments, the distal tip, in its initial radially contracted or delivered configuration, may have a bending resistance in the range of 0.1 N to 2 N, preferably in the range of 0.1 N to 0.5 N, more preferably in the range of 0.1 N to 0.35 N, and most preferably in the range of 0.1 N to 0.2 N.

[0072] Bending resistance is a measure of distal tip flexibility to navigate tortuous anatomy. Lower bending resistance indicates higher flexibility of the distal tip and better ability to navigate tortuous anatomy. Bending resistance of the distal tip (or any other part of the aspiration catheter) may be measured by a three-point bending test, e.g., "ASTM F2606 Standard Guide for Three-Point Bending of Balloon-Expandable Vascular Stents and Stent Systems" or equivalent. The catheter section is vertically rested on two lower static supports and a wedge is centered between them. The spacing between the two supports is 13 mm. The center of the supported catheter section is displaced by lowering a wedge held in the upper grip of an Instron tensile tester (Instron, Norwood, MA, USA) at a deflection rate of 5.0 mm / min while measuring the resistance force. The test is terminated when the displacement reaches 2 mm (approximately 15% of the span length). The three point bend resistance for that catheter section is equal to the maximum deflection force measured during the test.

[0073] A collapse pressure is a vacuum or negative pressure that, when applied to the proximal end of the catheter body lumen, will at least partially collapse the distal tip when the distal tip is completely occluded. By "at least partially collapse" is meant irreversible contraction (contraction that does not return after the applied vacuum is stopped) of more than 5%, more than 10%, or more than 15% of the distal tip inner lumen diameter or configuration. In a preferred embodiment, the distal tip inner lumen diameter or configuration comprising a plurality of expandable rings in an expanded (deployed) configuration under an applied vacuum is configured to cause the expandable rings in the expanded configuration to resist collapse when a vacuum is applied to the proximal end of the aspiration catheter and the distal tip becomes blocked or embolized with a blood clot or other material, or the rings are configured to resist collapse when in the expanded configuration of the rings under an applied vacuum and the tip engages a blood clot (or embolism) by contracting by no more than 5%, no more than 10%, or no more than 15% of any of the distal tip ring configurations, or preferably by contracting by no more than 10% of the expanded configuration under vacuum, or most preferably by contracting by no more than 5% of the expanded configuration under vacuum. In another embodiment, in an expanded deployed configuration, under a vacuum of about 1 atm, a distal tip inner lumen diameter or configuration comprising multiple expandable rings resists collapse by radially contracting by no more than 5% of any of the expandable rings, which radial contraction of no more than 5% is substantially reversible to the expanded configuration when the vacuum or negative pressure applied to the proximal end of the catheter body lumen with the central passage of the distal tip is removed or stopped (i.e., the distal tip inner lumen diameter or configuration expands to a larger expanded configuration).

[0074] In another embodiment, the present invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and a lumen extending along a longitudinal axis. A distal tip has a proximal end attached to the distal end of the tubular catheter body and a central passageway longitudinally continuous with the lumen (aspiration lumen) of the tubular catheter body. The distal tip is adapted to expand from an as-delivery configuration to a radially expanded configuration or from a radially contracted configuration to a radially expanded configuration in response to a radially outward expansion force applied within the distal tip, the distal tip comprising an expandable membrane and an expandable support structure such as a scaffold, the expandable scaffold or other expandable support structure comprising a plurality of rings spaced apart along the longitudinal axis with gaps therebetween. At least some of the rings comprise a malleable metal or metal alloy configured to plastically deform and circumferentially expand the scaffold or other expandable support structure in response to a radially outward expansion force applied from within the distal tip. In a preferred embodiment, the expandable tip, comprising an expandable membrane and an expandable scaffold or other expandable support structure, is configured to radially contract by no more than 15%, preferably no more than 10%, and more preferably no more than 5% of any of the expandable rings when a vacuum is applied to the proximal end of the aspiration lumen and the distal tip engages a blood clot (or embolus), and to passively expand (without an outward expansive force applied by the expandable member within the distal tip) when the applied vacuum is stopped (or removed), the expanded configuration being greater than the contracted configuration, preferably the expanded configuration being greater than the contracted configuration and substantially identical to the expanded configuration prior to the application of any vacuum. In another embodiment, the distal tip inner lumen diameter or configuration under a vacuum of about 1 atm radially contracts and resists collapse by no more than 15%, preferably no more than 10%, and more preferably no more than 5% in an expanded deployed configuration, and the radial contraction is substantially reversible (i.e., the distal tip inner lumen diameter or configuration expands to a larger configuration that is greater than the contracted configuration under vacuum) when the vacuum or negative pressure applied to the proximal end of the catheter body lumen using the central passage of the distal tip is removed or stopped.

[0075] In another embodiment, the present invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and an aspiration lumen extending along a longitudinal axis. A distal tip has a proximal end attached to the distal end of the tubular catheter body and a central passageway longitudinally continuous with the aspiration lumen of the tubular catheter body. The distal tip is adapted to expand from an as-delivery configuration (or from a first extraction configuration) to a first radially expanded configuration in response to an outward radial expansion force applied within the distal tip, the first radially expanded configuration (the second extraction configuration or the extraction configuration) spanning 1.1 to 2 times the as-delivery configuration, the distal tip comprising one or more expandable membranes and an expandable scaffold comprising a plurality of expandable rings spaced apart along the longitudinal axis with gaps therebetween, the expandable rings comprising structural elements including struts joined by crowns. At least some of the rings comprise a malleable metal or metal alloy configured to plastically deform and circumferentially expand the scaffold or other expandable support structure in response to a radially outward expansion force applied from within the distal tip. The expandable tip, comprising one or more expandable membranes and an expandable scaffold comprising a plurality of expandable rings, is configured to radially contract to a first contracted configuration that is smaller than the first expanded configuration but larger than the as-delivered configuration, preferably the first contracted configuration is 15% or less, preferably 10% or less, more preferably 5% or less, smaller than the first expanded configuration when a vacuum is applied to the proximal end of the aspiration lumen or when the applied vacuum ranges from 0.75 atm to about 1 atm, and the expandable tip ... when the applied vacuum is removed or stopped. the expandable tip is configured to passively expand to a second expanded configuration when the distal tip is withdrawn into a guiding catheter that is positioned proximal to the distal tip within the patient anatomy, the expandable tip being configured to contract to a second contracted configuration when the distal tip is withdrawn into a guiding catheter that is positioned proximal to the distal tip within the patient anatomy, the expandable tip being configured to contract to a second contracted configuration when the second contracted configuration is less than the first contracted configuration and equal to or greater than the as-delivered configuration.In one embodiment, the expandable distal tip has a length ranging from 0.5 mm to 500 mm, preferably ranging from 1 cm to 50 cm, more preferably ranging from 1 cm to 25 cm. The one or more expandable membranes of the expandable distal tip, in one embodiment, extend proximally beyond the proximal end of the distal tip of the aspiration catheter. In another embodiment, the one or more expandable membranes of the expandable distal tip have approximately the same length as the expandable scaffold, both of which are incorporated into or attached to the distal end of the aspiration catheter at their proximal ends. In yet another embodiment, the one or more expandable membranes extend from the distal end of the distal tip to the proximal end of the aspiration catheter.

[0076] In some cases, a distal tip comprising an expandable scaffold or other expandable support structure has a minimum bend radius in its as-delivered or radially contracted configuration without deformation and / or twisting of 5 mm, preferably 3 mm, more preferably 2 mm, and preferably in its radially expanded configuration without deformation and / or twisting of 10 mm, preferably 6 mm, more preferably 2 mm. The minimum bend radius may be determined by bending the distal tip around a cylinder of known radius and observing whether the distal tip deforms and / or twists.

[0077] In some cases, the rings of the expandable scaffold or other expandable support structure, when measured longitudinally, span a length ranging from 0.25 mm to 500 mm or more, preferably ranging from 1 mm to 100 mm, more preferably ranging from 10 mm to 70 mm, and most preferably ranging from 20 mm to 50 mm.

[0078] In another embodiment, the present invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and an aspiration lumen extending along a longitudinal axis. The distal tip has a proximal end embedded within the distal end of the tubular catheter body and a central passageway longitudinally continuous with the aspiration lumen of the tubular catheter body. The distal tip is adapted to expand from an as-delivery configuration to a first radially expanded configuration in response to an outward radial expansion force applied to the distal tip, the first radially expanded configuration spanning 1.1 to 2 times the as-delivery configuration, the distal tip comprising one or more expandable membranes and an expandable scaffold comprising one or more expandable rings spaced apart along the longitudinal axis with gaps therebetween, the expandable rings comprising structural elements including struts joined by crowns. The one or more rings are comprised of a malleable metal or metal alloy (or alternatively formed from a shape memory metal alloy) configured to plastically deform and circumferentially expand the scaffold or other expandable support structure in response to an outward radial expansion force applied from inside the distal end or tip. In a specific embodiment, the expandable scaffold is comprised of one, two, or three expandable rings. In another specific embodiment, the expandable scaffold is comprised of one expandable ring.

[0079] In some cases, a distal tip comprising an expandable scaffold or other expandable support structure has a minimum bend radius in its as-delivered or radially contracted configuration without deformation and / or twisting of 5 mm, preferably 3 mm, more preferably 2 mm, and preferably in its radially expanded configuration without deformation and / or twisting of 10 mm, preferably 6 mm, more preferably 2 mm. The minimum bend radius may be determined by bending the distal tip around a cylinder of known radius and observing whether the distal tip deforms and / or twists.

[0080] In some cases, the rings of the expandable scaffold or other expandable support structure, when measured longitudinally, span a length ranging from 0.25 mm to 500 mm or more, preferably ranging from 1 mm to 100 mm, more preferably ranging from 10 mm to 70 mm, and most preferably ranging from 10 mm to 40 mm.

[0081] In some cases, the expandable scaffold or other expandable support structure comprises 1 ring to 800 or more rings, preferably 25 rings to 650 or more rings, more preferably 50 rings to 500 or more rings, spanning one or more expandable axial section lengths ranging from 0.2 mm to 50 cm, preferably 10 mm to 40 cm, more preferably 15 mm to 25 cm, the rings being arranged longitudinally from the distal end of the distal tip to the distal or proximal end of the aspiration catheter. In preferred embodiments, the expandable scaffold or other expandable support structure comprises or consists of a number of rings per mm of axial (longitudinal) scaffold or other expandable support structure length ranging from 2 rings / mm to 5 rings / mm in length, preferably 2.5 rings / mm to 4 rings / mm in length, more preferably 3 rings / mm to 4 rings / mm in length of axial (longitudinal) scaffold length.

[0082] In some cases or embodiments, the expandable support structure comprises a plurality of adjacent rings with a gap between adjacent rings, hi some embodiments, the gap between adjacent rings has a length measured in the longitudinal / axial direction in the range of 0.0125 mm to 0.25 mm, preferably in the range of 0.025 mm to 0.2 mm, and more preferably in the range of 0.05 mm to 0.17 mm.

[0083] In some cases, the axial length of the gap between adjacent rings (i.e., the gap length measured axially) may be constant. In other cases, the axial length of the gap between adjacent rings may be variable. For example, the gap length (or axial length) between at least some adjacent rings ranges from 0.05 mm to 0.2 mm. In another preferred embodiment, the plurality of adjacent rings spans at least a 3 mm segment along the length of the expandable structure, more preferably at least a 7 mm segment along the length of the expandable structure, and more preferably at least a 20 mm segment along the length of the expandable structure, and adjacent rings have a gap length adjacent adjacent rings that ranges from 0.05 mm to 0.2 mm.

[0084] In some cases, the distal tip has at least 2 rings per mm of axial length, preferably at least 3 rings per mm of length, typically 1.5 to 5 rings per mm of length, more typically 2 to 5 rings per mm of length, or more typically 3 to 4 rings per mm of length.

[0085] In some preferred cases, at least some of the adjacent rings are joined end-to-end in a helical arrangement. In other cases, at least some of the adjacent rings are planar, arranged in parallel, joined by axial links or other means, e.g., attachment points, and are not joined end-to-end. The parallel planes may be normal or inclined to the longitudinal axis of the distal tip in its delivery configuration. The adjacent rings may be joined, preferably, by a single axial link or attachment point, or no more than two axial links or no more than two attachment points. In some preferred cases, at least some of the adjacent rings of the expandable scaffold are joined end-to-end in a helical pattern or arrangement. In other cases, at least some of the adjacent rings of the expandable scaffold are planar, arranged in parallel, and joined by axial links or attachment points that join or connect structural elements on the adjacent rings. In this other case, the adjacent rings of the scaffold are not joined end-to-end in a helical arrangement. The parallel plane may be normal or inclined relative to the longitudinal axis of the distal tip in its delivery configuration. Adjacent rings may preferably be joined by a single axial link or attachment point, or by no more than two axial links or attachment points.

[0086] In other cases, at least some adjacent rings of the expandable scaffold are planar, arranged in parallel, and not connected to each other (not connected by a link, attachment point, or joined end-to-end in a helical arrangement). The parallel planes may be normal or inclined to the longitudinal axis of the distal tip in its as-delivered configuration. At least some adjacent rings are covered by one or more membranes that, in this case, adhere to the non-connected adjacent rings and hold them together, allowing at least some adjacent rings to expand from the as-delivered configuration to the expanded configuration. This allows for improved deliverability of the distal tip to navigate the vascular anatomy in the as-delivered configuration, and allows at least some rings to expand from the as-delivered configuration to the expanded configuration and resist collapse of the distal tip from the expanded configuration when a vacuum is applied to the proximal end of the aspiration lumen and a blood clot engages the distal end of the distal tip (or an embolism is blocked).

[0087] In some cases, at least some of the adjacent rings in the spiral and / or planar array may comprise non-linearity.

[0088] In some cases, all adjacent rings in the spiral and / or planar array are free of nonlinearity.

[0089] In some cases, at least some of the adjacent rings have a thickness ranging from 0.03 mm to 0.3 mm, preferably ranging from 0.05 mm to 0.25 mm, and more preferably ranging from 0.05 mm to 0.2 mm.

[0090] In some cases, the malleable metal is cobalt chrome, e.g., L-605, MP35N, Stellite 6B, ASTM F1537 / F799 Alloy 1, ASTM F1537 / F799 Alloy 2, stainless steels, e.g., 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L, and 420S, tantalum, niobium, tungsten, molybdenum, molybdenum, molybdenum alloys, e.g., molybdenum-rhenium (wherein the sum of the two constitutes up to 90%-100% and may contain one or more metals, e.g., boron, calcium, chromium, cobalt, copper, gold, iron, lead, magnesium, etc. , manganese, mercury, nickel, niobium, platinum, rare earth metals, silicon, silver, sulfur, tantalum, tin, titanium, tungsten, yttrium, zinc, and zirconium), platinum, platinum alloys, e.g., platinum-iridium, platinum-chromium, platinum-cobalt-chromium, magnesium, magnesium alloys, e.g., Mg-3A1-1Z, Mg-Zn-Se, and Mg-Zn-Cu, zinc, or the like, or others.

[0091] In some cases, the scaffold or other expandable support structure comprises a metal or metal alloy selected from the group consisting of Nitinol, superelastic Nitinol, or the like, or others. In such cases, the expandable support structure is constrained in a delivery configuration and allows the scaffold to expand to an expanded configuration when released from the constraint.

[0092] In some cases, the expandable membrane comprises one or more of an elastic membrane, and / or a non-elastic but stretchable membrane, and / or one or more plastically deformable membranes (the membranes may comprise one or more membranes comprising a polymer, an elastomer, or others as listed above).

[0093] In some cases, the elastic membrane may have isotropic properties. In other cases, the elastic membrane may have anisotropic properties. For example, the membrane may have higher elasticity in the circumferential direction than in the axial direction.

[0094] In some cases, the expandable membrane may comprise an elastic membrane, a non-elastic but extensible membrane, or other types of expandable materials. Suitable material examples are as listed above.

[0095] In some cases, the inelastic membrane may be configured to stretch or plastically deform as the scaffold or other expandable support structure expands, hi other cases, the inelastic membrane may be configured to unfold as the scaffold or other expandable support structure expands.

[0096] In some cases, the distal tip may be formed by heat shrinking a tubular membrane onto an expandable scaffold or other expandable support structure. In other cases, the distal tip may be formed by laminating an expandable scaffold or other expandable support structure between layers of a tubular membrane. For example, the layers may be bonded together such that there is a seal between the layers. In a preferred embodiment, one or more expandable membranes, when in a delivery configuration and expanded to an expanded configuration, flow to and cover at least some side surfaces of the structural elements of the expandable support structure and adhere to the structural elements sufficiently to provide a unified system. In yet another embodiment, polymer layers on an outer surface of the scaffold and on an inner surface of the scaffold may be bonded together and / or adhered to the scaffold structural elements such that there is a seal between the layers and / or adhesion to the structural elements to provide a unified integrated system expandable from the delivery configuration to the expanded configuration. In a preferred embodiment, the structural elements of the scaffold do not move or expand freely without moving or expanding the expandable membrane adjacent to the structural elements. In yet another example, the layers on the outer scaffold surface and the inner scaffold surface may be bonded to one another such that a seal exists between the layers. In yet another example, the layers on the outer scaffold surface and the inner scaffold surface may be bonded, attached, and / or adhered to one another to substantially eliminate (or fill) gaps between structural elements of the scaffold and provide a unified, expandable scaffold expandable from an as-delivered configuration to an expanded configuration. In yet another example, one or more layers on the outer surface of the scaffold or one or more layers on the inner surface of the scaffold are fused or laminated onto the structural elements of the scaffold, at least partially eliminating gaps between and adhering to the structural elements and providing the scaffold with the ability to expand as a unified system from an as-delivered configuration to an expanded configuration.

[0097] In some cases, the tubular membrane may be comprised of at least two membrane compartments, which may comprise a single type of material, at least two types of material, or three or more different material types.

[0098] In some cases, the at least two membrane compartments may cover at least the exterior surface of the expandable scaffold or other expandable support structure. In some cases, the at least two membrane compartments may cover at least the interior surface of the expandable scaffold or other expandable support structure. In some cases, the at least two membrane compartments both cover the interior and exterior surfaces of the expandable scaffold or other expandable support structure, with at least one membrane compartment of the at least two membrane compartments covering the exterior surface of the scaffold while at least a second membrane compartment covers the interior surface of the expandable scaffold.

[0099] In some cases, the tubular catheter body may be reinforced over at least a portion of its length by a catheter scaffold or other support structure, typically a flexible but non-expandable support structure. In specific examples, the catheter scaffold or other support structure may be formed contiguously with the expandable scaffold or other expandable support structure. For example, the catheter and support scaffolds may be patterned from the same tube or bent wire. In other cases, the catheter scaffold and the expandable scaffold may be formed from one or more bent wires, which typically span at least a portion of the non-expandable catheter scaffold and the expandable distal tip scaffold, respectively.

[0100] In some cases, the expandable scaffold may further comprise multiple cantilever or other support elements, each having a base end and a free end, the base end attached to one of the radially expandable rings and the free end extending toward or into an adjacent axial and / or circumferential gap.

[0101] In some cases, at least some of the multiple rings may include struts that are joined by bends (crowns), and at least some of the multiple support elements have their base ends attached to the struts, and at least some of the multiple support elements have their base ends attached to the bends (crowns).

[0102] In some cases, at least some of the multiple support elements may have their base ends attached to the inner surface of the ring, i.e., the inner bend of the crown.

[0103] In some cases, at least some of the multiple support elements may have their base ends attached to the outer surface of the ring, i.e., the outer surface of the crown or to an apex of the outer surface of the crown.

[0104] In some cases, at least some of the multiple support elements have a constant width over their distal portions. In some cases, at least some of the multiple support elements have a constant width over their entire lengths.

[0105] In some cases, at least some of the multiple support elements have variable widths across their distal portions.

[0106] In some cases, at least some of the multiple support elements have distal tips that extend into adjacent circumferential, axial, or other gaps.

[0107] In some cases, at least some of the multiple support elements have distal tips that terminate flush with the bend that joins the strut.

[0108] In some cases, at least some of the multiple support elements have distal tips that are recessed between adjacent bends that join the struts.

[0109] In a fifth aspect, the invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and a lumen extending along a longitudinal axis. The distal end comprises an expandable distal tip and a central passageway, typically longitudinally continuous with the lumen of the tubular catheter body. The distal tip is adapted to expand from a radially contracted or as-delivered configuration to a radially expanded configuration in response to a radially outward expansion force applied to the interior of the distal tip, the distal tip including a tubular membrane covering (e.g., adhered to, attached to, bonded to, or laminated with) the expandable scaffold or expandable support scaffold. The expandable scaffold or expandable support scaffold comprises a plurality of rings spaced apart along a longitudinal axis with gaps (extending between the rings) therebetween, at least some of the rings comprising circumferentially adjacent cells having bends (such as crowns) configured to unbend (such as expand) in response to a radially outwardly expanding force applied to the inside of the distal tip, allowing the rings to expand from a radially contracted or delivery configuration to a radially expanded configuration, the radially expanded configuration being larger than the contracted configuration. In some preferred cases, at least some adjacent rings of the expandable scaffold or expandable support scaffold are joined end-to-end in a helical arrangement, typically without axial connections or attachment points. In preferred cases, at least some adjacent rings of the expandable scaffold or expandable support scaffold have a fixed cell amplitude within each ring. In other cases, at least some adjacent rings of the expandable scaffold or expandable support scaffold have a fixed cell amplitude within at least some rings. In rare cases, at least some adjacent rings of the expandable scaffold or expandable support scaffold may have variable cell amplitudes within each ring or at least some of the rings, where at least some adjacent rings have a pitch angle relative to the longitudinal axis of the scaffold or distal tip as patterned or delivered within the range of 70°-89.9°, or 75°-89.9°, typically 80°-89.9°, more typically 84°-89.75°, and frequently 85°-88.5°.As used herein and illustrated in the drawings, a "pitch angle" will be an acute angle (0°-90°) and not an obtuse angle (90°-180°) formed by a ring with respect to the longitudinal axis of the distal tip of the aspiration catheter. In certain other cases, at least some adjacent rings of the expandable scaffold or expandable support scaffold are planar, arranged in parallel, and joined by one axial link or attachment point joining structural elements on adjacent rings. In rare cases, at least some adjacent rings are joined by no more than two axial links, no more than two attachment points joining structural elements on adjacent rings, or no more than one link and no more than one attachment point. The parallel plane may be normal or inclined with respect to the longitudinal axis of the distal tip in its delivery configuration.

[0110] In some cases, the cells may be arranged in any one or more of a box pattern, a diamond pattern, a sine wave pattern, a serpentine pattern, an omega wave pattern, a zigzag pattern, a square wave pattern, a rectangular wave pattern, a wavy pattern, a slotted pattern, an open cell pattern, a closed cell pattern, a combination of open and closed cells, a combination of patterns, or the like and the like.

[0111] In some cases, adjacent and / or non-adjacent rings have crowns that are in phase or out of phase.

[0112] In some cases, the cells may include struts that are joined by bends.

[0113] In some cases, at least some of the expandable cells on one or more rings of the expandable scaffold, or at least some of the expandable cells on at least some of the rings of the expandable scaffold, or at least some of the expandable cells on each ring of the expandable scaffold, or at least some of the circumferentially adjacent cells on at least some of the rings of the expandable scaffold, or at least some of the circumferentially adjacent cells on at least some of the adjacent rings of the expandable scaffold, or substantially all of the cells on the expandable scaffold, or all of the cells along the length of the scaffold that are less than the length of the scaffold, or all of the cells along the length of the scaffold have a cell period (the distance between like points on circumferentially adjacent cells measured in a contracted configuration) in the as-delivered configuration or in the as-patterned configuration within the range of 0.03 mm to 1.3 mm, preferably 0.04 mm to 0.8 mm, more preferably 0.05 mm to 0.5 mm, and most preferably 0.05 mm to 0.15 mm. Having a small cell period increases the circularity of the ring, or the circularity of the multiple rings, or the circularity of the expandable scaffold, thereby improving navigation of the expandable scaffold into the vasculature without distortion or kinking in the as-delivered configuration, and the improved circularity resists collapse of the expandable distal tip when a vacuum is applied to the proximal end of the aspiration catheter while the expandable distal tip is engaged (or embolized) with a clot when expanded to the expanded configuration. Additionally, having a small cell period increases (or improves) the suction area within the ring, or the multiple rings, or the expandable scaffold or expandable distal tip.

[0114] In some cases, circumferentially adjacent cells on at least one ring or at least some rings of the expandable scaffold (or at least some circumferentially adjacent cells on the same ring, or at least some circumferentially adjacent cells on at least some adjacent rings), or at least one ring or at least some rings or all rings of the expandable scaffold, in the as-delivered or as-patterned configuration, may have a peak-to-peak amplitude (longitudinal / axial ring width (axial width of the ring)) in the range of 0.05 mm to 1.2 mm, preferably 0.05 mm to 0.8 mm, more preferably 0.15 mm to 0.5 mm, and most preferably 0.15 mm to 0.35 mm. In a preferred embodiment, the cell amplitude of each cell on the same ring has the same length (is fixed or constant) in the as-delivered or as-patterned configuration. In another preferred embodiment, at least some adjacent rings have cell or ring amplitudes on at least some rings that are the same length. Having a small amplitude improves the flexibility of the expandable scaffold, thereby improving navigation of the expandable scaffold (or the expandable distal tip) when the aspiration catheter is advanced into the vasculature. Additionally, having a small amplitude further stiffens the expandable scaffold in the expanded configuration and resists collapse of the scaffold or an expandable membrane coupled to the scaffold when vacuum is applied to the proximal end of the aspiration catheter and the distal tip engages a clot.

[0115] In some cases, the circumferentially adjacent cells (or at least some of the circumferentially adjacent cells, or at least some of the circumferentially adjacent cells on at least some of the adjacent rings, or all of the cells on the expandable scaffold, or at least some of the cells in a ring, or all of the cells in at least some of the rings, or all of the cells in a ring of the expandable scaffold) may have a cell period vs. (peak-to-peak axial width of the ring) amplitude range as follows, when measured in the delivery configuration or in the as-patterned configuration, for all embodiments: In one embodiment, the cell period vs. (peak-to-peak axial width of the ring) amplitude ranges from 0.3:1 to 1.6:1. In other embodiments, the cell period vs. (peak-to-peak axial width of the ring) amplitude ranges from 0.4:1 to 1.5:1. In yet other embodiments, the cell period vs. (peak-to-peak axial width of the ring) amplitude ranges from 0.5:1 to 1.3:1. In yet other embodiments, the cell period vs. (peak-to-peak axial width of the ring) amplitude ranges from 0.6:1 to 1.2:1. In yet other cases, the cell period vs. (peak-to-peak axial width of the rings) amplitude ranges from 1:1 to 1.6:1. In yet other cases, the cell period vs. (peak-to-peak axial width of the rings) amplitude ranges from 0.3:1 to 1.2:1. In some other examples, circumferentially adjacent cells (or at least some cells on a ring, or on a plurality of rings, or on at least some of the rings, or all cells on at least one ring, or on at least some of the rings, or at least some of the rings of an expandable scaffold) may have a cell period and (peak-to-peak axial width of the rings) amplitude, as measured in the delivery configuration (or as measured in the as-patterned configuration), each having a length of 0.25 mm ± 0.2 mm, preferably each having a length of 0.25 mm ± 0.15 mm, and more preferably each having a length of 0.25 mm ± 0.1 mm. Having at least some cell periods and amplitude lengths within a ring or within multiple rings or within at least some of the rings that are within ±0.2 mm of each other improves the symmetry and / or occlusion of the rings of the expandable scaffold and resists deformation and / or kinking as the expandable scaffold navigates through the vasculature in its delivery configuration.

[0116] In some cases, each ring (or at least some of the rings) may include between 2 cells and 15 cells per mm of circumference, preferably, each ring (or at least some of the rings) may include between 3 cells and 10 cells per mm of circumference, and most preferably, each ring (or at least some of the rings) may include between 4 cells and 9 cells per mm of circumference.

[0117] In some cases, at least some of the rings in a scaffold or other expandable support structure may have a ratio of (1) the number of bends to (2) the circumference, typically in the range of 0.8 per mm to 15 per mm, preferably 1 per mm to 15 per mm, more preferably 2 per mm to 15 per mm, more preferably 3 per mm to 15 per mm, and most preferably 4 per mm to 12 per mm. Support structures having cantilevered or other support elements will typically have fewer bends per unit length of ring circumference.

[0118] The ratio of (1) the number of bends to (2) the circumference may be constant or variable across at least some of the rings across all or a portion of the scaffold or other expandable support structure.

[0119] In some cases, the ring may span a section of the distal tip having a length within the distal tip, measured longitudinally, within the range of 0.5 mm to 500 mm or more, usually 10 mm to 100 mm, more usually 10 mm to 40 mm.

[0120] In some cases, the ring may span a section of the distal tip having a length within the distal tip, measured in the longitudinal direction, of 0.5 mm to 500 mm or more, usually 10 mm to 100 mm, more usually 10 mm to 40 mm. In some cases, the scaffold is comprised of a single expandable ring that spans a length within the distal tip, measured in the longitudinal direction, of 0.1 mm to 0.5 mm, usually 0.15 mm to 0.35 mm, more usually 0.15 mm to 0.3 mm.

[0121] In some cases, the distal tip may have 1-10 rings per mm of distal tip length, usually 2-8 rings per mm of distal tip length, and more usually 3-5 rings per mm of distal tip length.

[0122] In preferred embodiments, the rings of the expandable support structure comprise flexures, e.g., crowns, and struts, the flexures having lengths measured along their arcs and the struts having axial lengths, and the ratio of the arc length of the flexures or crowns to the axial length of the struts ranges from 0.2:1 to 2:1, preferably 0.5:1 to 1.5:1, and more preferably 0.75:1 to 1.25:1. In specific preferred embodiments, the arc length of the crowns and the axial length of the struts connected to the crowns are each within the range of 0.05 mm to 0.25 mm, preferably 0.075 mm to 0.225 mm, more preferably 0.1 mm to 0.2 mm, preferably about 0.15 mm, or preferably 0.15±0.05 mm, e.g., 0.15±0.05 mm.

[0123] In some cases, at least some of the adjacent rings in the expandable distal tip may be formed from tubes or bent wires and joined end-to-end in a helical arrangement. For example, at least some of the adjacent rings may be joined with an absolute pitch angle relative to the longitudinal axis within the range of 70°-89.9°, or 75°-89.9°, typically 80°-89.9°, more typically 84°-89.75°, and frequently 85°-88.5°, when patterned or delivered. The absolute pitch angle may be constant or variable along at least some of the rings, or along the length of the expandable structure (or along the length of the expandable scaffold or other expandable support structure, the length of which is less than the length of the scaffold) or other expandable support structure. The absolute pitch angle of at least some of the adjacent rings may be constant or variable along the length of the expandable structure or other expandable support structure. The pitch angle is typically measured in the as-patterned configuration. Alternatively, the pitch angle may be measured in the as-delivered configuration. In preferred cases, at least some adjacent rings have no ties or attachment points between adjacent rings. In other preferred cases, at least some adjacent rings have fixed cell amplitudes within each ring or at least within adjacent rings. In rare cases, at least some adjacent rings may have attachment points or ties that connect to adjacent rings. In other rare cases, at least some adjacent rings may have variable cell amplitudes or variable ring amplitudes within each ring or within adjacent rings.

[0124] In other cases, at least some of the adjacent rings may be arranged as separate parallel planes and joined by axial connections or other means, such as crowns on the adjacent rings that are fused / soldered or otherwise joined together (attachment points). The separate parallel planes, when straightened, may be oriented perpendicular or at an angle to the longitudinal axis of the scaffold or other expandable support structure. In some cases, the separate adjacent rings are not joined together by connections or other means, but are held together by one or more expandable membranes that contain, cover, and / or embed the separate rings.

[0125] In some cases, at least some of the cells may comprise a malleable metal or metal alloy that is configured to plastically deform. The malleable metal may comprise a metal or metal alloy as previously identified in this application.

[0126] In some cases, the radially contracted configuration of the scaffold or other expandable support structure and / or distal tip may have a maximum diameter in the range of 0.5 mm to 30 mm, typically 1.3 mm to 5.5 mm, and the radially expanded configuration may have a minimum diameter in the range of 1 mm to 40 mm, typically 2 mm to 5.5 mm.

[0127] In some cases, the distal tip may be configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to a radially outward expansive force applied within the distal tip.

[0128] In some cases, the distal tip may be configured to expand from an initial cylindrical shape to an expanding conical configuration in response to a radially outward expansive force applied within (or applied from the inside out) the distal tip.

[0129] In some cases, circumferentially adjacent cells in at least some of the rings in the distal tip may have round, oval, elliptical, flat, or generally flat outer and / or inner surfaces that define "facets" in the polygonal structure. In those cases, the rings may have a first radius from the axial centerline of the ring to the circumferential center of each facet and a second radius from the axial centerline of the ring to the circumferential edge of each facet, the length of the first radius being 97%-99.9%, preferably 98%-99.7%, more preferably 98.5%-99.5%, and most preferably 99%-99.5% of the length of the second radius in the expanded configuration. This provides the expandable distal tip with one or more of the following: an enlarged inner lumen configuration (or a maximum inner lumen configuration); an improved aspiration lumen area; maximizing the aspiration lumen area in the expanded configuration; resisting collapse under vacuum when the distal tip is engaged with a clot (or blocked or embolized with a clot or other material) in the expanded configuration; improving deliverability of the aspiration catheter distal tip; and improving deformation or kink resistance of the expandable distal tip in the delivery configuration when navigating the vasculature. In a preferred case, the expandable tip has a "circularity" (as defined below with respect to FIG. 16) in the expanded configuration ranging from 97% to 99.9%, preferably ranging from 98% to 99.5%, and more preferably ranging from 98.5% to 99.5%. In another preferred case, the circularity of the expandable tip is greater than 97%, preferably greater than 98%, more preferably greater than 98.5%, and most preferably greater than 90% in the expanded configuration. The circularity of the expandable distal tip refers to the inner lumen configuration. Alternatively, the circularity of the expandable distal tip measures the circumference of the distal tip.

[0130] In some cases, the tubular catheter body may have a length from proximal to distal end in the range of 50 cm to 200 cm, an outer diameter in the range of 0.5 mm to 30 mm, and an inner lumen diameter of 0.25 mm to 25 mm. In one embodiment, the expandable distal tip length ranges from 0.5 mm to 50 cm. In another embodiment, the expandable distal tip length is the same as the distal tip length. In other embodiments, the expandable distal tip comprises substantially the entire length of the catheter tubular body. In yet another embodiment, the expandable distal tip is comprised of an expandable scaffold (or expandable support scaffold) coated with or embedded in one or more polymeric materials, the expandable scaffold comprising one circumferential ring comprising a plurality of struts joined by crowns, the ring being expandable from an as-delivered configuration to an expanded configuration, the ring resisting collapse when a vacuum is applied to the proximal end of the aspiration lumen and the distal end of the distal tip is against a blood clot or is embolized. In certain other cases, the expandable scaffold comprises 2, 3, 4, or 5 circumferential rings.

[0131] In some cases, the expandable distal tip may further comprise multiple support elements, each having a proximal end and a free end, with the proximal end attached to one of the radially expandable rings and the free end extending axially and / or circumferentially relative to the distal tip toward or into an adjacent gap. For example, at least some of the multiple rings may comprise struts that are joined by bends, and at least some of the multiple support elements may have their proximal ends attached to the struts, and / or at least some of the multiple support elements may have their proximal ends attached to the bends.

[0132] In other cases, at least some of the multiple support elements may have their base ends attached to an inner surface of the ring (or a structural element of the ring) and / or attached to an outer surface of the ring (or a structural element of the ring).

[0133] In some cases, at least some of the multiple support elements may have a constant width across their distal portions or along their entire length. In other cases, at least some of the multiple support elements may have a variable width across their distal portions or along their length. In other cases, at least some of the multiple support elements may have a larger width at their bases and a constant width along the remaining length of the support elements. In preferred embodiments, the width of the support elements is greater than the width of adjacent struts, crowns, or ring sections. Having a support element width greater than adjacent structural elements allows for contraction of the expandable scaffold or other expandable support structure after expansion of the scaffold to the expanded configuration when the scaffold is withdrawn into a guiding catheter that has a smaller inner lumen than the expanded configuration of the expandable scaffold.

[0134] In some cases, at least some of the multiple support elements may have distal tips that extend toward and / or into adjacent circumferential and / or axial gaps.

[0135] In some cases, at least some of the multiple support elements may have distal tips that terminate flush with the adjacent bends or crowns that join the struts.

[0136] In some cases, at least some of the multiple support elements have distal tips that are recessed between adjacent bends that join the struts in the delivery configuration, and the support elements protrude further toward or into the adjacent gap.

[0137] In yet another aspect, the present invention provides a method for aspirating a blood clot from a patient's vasculature, comprising positioning a distal tip of any one of the aspiration catheters described herein at a region of a blood clot in the patient's vasculature. The distal tip is expanded from an as-delivery configuration to its radially expanded configuration, engaging the vessel wall adjacent the region of the blood clot or engaging the blood clot, and negative pressure is applied to the proximal end of a lumen within the catheter body to aspirate the blood clot into a central passage (aspiration lumen) of the expanded expandable support structure. The expanded configuration has a greater suction force than the as-delivery configuration under the same applied vacuum. The suction force is in the range of 1.1 to 10 times greater, preferably in the range of 1.5 to 6 times greater, and more preferably in the range of 1.8 to 6 times greater, in the expanded configuration than the suction force of the as-delivery configuration.

[0138] In some cases, at least a portion of the expandable scaffold or other expandable support structure remains at least partially unexpanded after expansion of another portion of the expandable scaffold. The at least partially unexpanded portion may have a variety of shapes, for example, a conical shape, an oval shape, an oblong shape, a flat shape, or other shapes. In certain other cases, at least one section of the expandable scaffold or other expandable support structure remains unexpanded after expansion of another adjacent section of the expandable scaffold or other expandable support structure to an expanded configuration.

[0139] In yet another aspect, the invention provides a method for aspirating a blood clot from a patient's vasculature, comprising positioning a distal tip of any one of the aspiration catheters described herein at a region of a blood clot in the patient's vasculature. At least a section of the distal tip is expanded from an as-delivery configuration (a contracted configuration) to its radially expanded configuration to engage the vessel wall adjacent the region of the blood clot or to engage the blood clot, and negative pressure is applied to the proximal end of the lumen within the catheter body to aspirate the blood clot into the central passage of the expanded expandable structure. In other embodiments, the blood clot is aspirated in the contracted (as-delivery) configuration without expanding the distal tip to the expanded configuration.

[0140] In some cases, a section or other portion of an expandable scaffold or other expandable support structure remains at least partially unexpanded after expansion of another portion of the expandable scaffold.

[0141] In yet another aspect, the present invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and a lumen extending along a longitudinal axis. An expandable coil comprising continuous helical windings is disposed along the longitudinal axis, the expandable coil comprising undulating bends and struts, the continuous windings having gaps therebetween, the continuous windings being inclined at an acute pitch angle relative to the longitudinal axis. A jacket is disposed about the expandable coil. In preferred embodiments, the acute pitch angle ranges from 70° to 89.9°, typically 80° to 89.75°, and more typically 82° to 89.75° degrees relative to the longitudinal axis in the patterned or delivery configuration. In preferred cases, at least some of the continuous windings are free of links or attachment points joining the adjacent windings. In yet another preferred case, at least some of the adjacent windings have a fixed cell amplitude within each winding or within at least some adjacent windings.

[0142] In some cases, the expandable scaffold or other expandable support structure is comprised of an expandable coil comprising a plurality of adjacent expandable rings joined end-to-end in a helical arrangement, each ring comprising a structural element comprising struts joined by crowns, the expandable coil having an acute pitch angle relative to a longitudinal axis when patterned or delivered ranging from 70° to 89.9°, preferably ranging from 80° to 89° degrees. The expandable coil is expanded from an as-delivered or contracted configuration to an expanded configuration by an expandable support structure, e.g., a balloon catheter, which is radially expanded within the interior of the expandable coil, the expandable coil being said to be balloon expandable.

[0143] In some cases, the expandable coil may be configured to be expanded by an expandable support structure that is radially expanded within the expandable coil. For example, the expandable coil may be balloon expandable.

[0144] In some cases, the coil may be formed, at least in part, from a malleable metal or metal alloy. In certain other examples, the coil may be formed, at least in part, from a malleable metal or metal alloy.

[0145] In certain other cases, the coil may be formed from a shape memory metal or alloy, and the expandable distal tip is constrained in a delivery configuration and expands to a larger expanded configuration when released. Examples of shape memory alloys include nickel titanium alloys or others.

[0146] In some cases, at least a proximal portion of the tubular catheter body may be non-expandable.

[0147] In some cases, at least a proximal portion of the tubular catheter body may be radially expandable.

[0148] In some cases, the expandable coil may be attached to a stiffening member at the proximal section of the catheter body.

[0149] In some cases, the expandable coil and the reinforcing member may be formed from a continuous wire or tube.

[0150] In some cases, adjacent rings may be joined at an acute pitch angle in the patterned or delivered configuration relative to the longitudinal axis in the range of 70° to 89.9°, preferably in the range of 80° to 89.9°, more preferably in the range of 85° to 89°, and most preferably in the range of 86° to 89°.

[0151] In some cases, the expandable coil may be attached to, integrated within, or coupled to the distal end of the tubular catheter body. In certain other cases, the expandable coil may extend from the distal end to the proximal end, i.e., the proximal end, of the tubular catheter body. The expandable coil may be attached to the proximal end of the tubular catheter body in some cases.

[0152] In some cases, the expandable coil is embedded or laminated within an expandable membrane or embedded or laminated within a tubular catheter body.

[0153] In some cases, the expandable coil may have a crimped delivery configuration and an expanded deployed configuration.

[0154] In some cases, the expandable coil's crimped delivery configuration has a maximum outer diameter in the range of 0.5 mm to 30 mm, and the expanded deployed configuration has a maximum outer diameter in the range of 1.5 mm to 40 mm.

[0155] It is to be understood that all features and aspects of the apparatus and methods of the invention described herein may be arranged in different combinations and are covered by the claims, even if specific embodiments or examples are not provided in a particular combination. Features described in whole or in part in all paragraphs, examples, embodiments, figures, and other aspects as described herein may be combined in ways not specifically described and may be part of the invention. [Brief description of the drawings]

[0156] [Figure 1] FIG. 1 illustrates a first system constructed in accordance with the principles of the present invention, comprising: (1) an aspiration catheter having an expandable distal tip; and (2) a distal tip dilation catheter.

[0157] [Figure 1A]FIG. 1A illustrates a second system constructed in accordance with the principles of the present invention, comprising (1) an aspiration catheter having an expandable distal tip, and (2) a distal tip dilation catheter.

[0158] [Figure 1A-1] FIG. 1A-1 is a detailed view of the area defined by boundary line 1A-1-1A-1 of FIG. 1A.

[0159] [Figure 1A-2] FIG. 1A-2 is a detailed view of the area defined by boundary line 1A-2-1A-2 of FIG. 1A.

[0160] [Figure 1B] FIG. 1B illustrates the system of FIG. 1A as it is introduced to a target location within the cerebral vasculature via the femoral artery.

[0161] [Figure 2A] 2A is a detailed view of an example of an expandable distal tip of an aspiration catheter of the system of FIG. 1 shown in a non-expanded configuration (or as-delivered configuration) with a portion of a covering (or laminated) membrane removed or broken to expose the expandable support scaffold or other expandable support structure. A reinforcing coil, which is continuously connected to the expandable support scaffold or other expandable support structure proximal end, is formed to be continuously connected to the expandable support scaffold proximal end as shown. The expandable distal tip configuration and the non-expandable proximal section (reinforcing coil) configuration of FIG. 2A have the same delivery configuration (or have the same outer diameter profile) in this example.

[0162] [Figure 2B] 2B is an "unfolded" view of an embodiment of an expandable support scaffold or other expandable support structure of the expandable distal tip of the aspiration catheter of the system of FIG 1. A reinforcing structure is shown that is formed contiguous with the expandable support structure proximal end.

[0163] [Figure 2C]FIG. 2C is a detailed view of an adjacent pair of circumferentially expandable support rings of the expandable distal tip of the aspiration catheter of the system of FIG. 1, showing the support elements in most, but not all, cells and the links joining adjacent rings.

[0164] [Figure 3A] 3A-3D illustrate a support scaffold or other expandable support structure embodiment of the expandable distal tip of the aspiration catheter of FIGS. 2A-2C shown in an alternative expanded configuration. [Figure 3B] 3A-3D illustrate a support scaffold or other expandable support structure embodiment of the expandable distal tip of the aspiration catheter of FIGS. 2A-2C shown in an alternative expanded configuration. [Figure 3C] 3A-3D illustrate a support scaffold or other expandable support structure embodiment of the expandable distal tip of the aspiration catheter of FIGS. 2A-2C shown in an alternative expanded configuration. [Figure 3D] 3A-3D illustrate a support scaffold or other expandable support structure embodiment of the expandable distal tip of the aspiration catheter of FIGS. 2A-2C shown in an alternative expanded configuration.

[0165] [Figure 3E] FIG. 3E illustrates a support scaffold (or scaffolding) or other expandable support structure similar to that shown in FIG. 2A shown in an unexpanded configuration (or as-delivered configuration) with a reduced distal configuration relative to a proximal section having a larger configuration to facilitate introduction over a guidewire for improved deliverability into the vasculature.

[0166] [Figure 4A] FIG. 4A is a "unfolded" view of an embodiment of a support scaffold or other expandable support structure having helically arranged circumferential support rings constructed in accordance with the principles of the present invention.

[0167] [Figure 4B] FIG. 4B is a detailed view of adjacent circumferential support rings of the expandable distal tip of the support scaffold of FIG. 4A.

[0168] [Figure 4C] FIG. 4C is an image of the support cell space of FIG. 4A embedded within a polymeric tubular shell (one or more membranes) in an unexpanded configuration (as-delivered configuration).

[0169] [Figure 4D] FIG. 4D is an image of the supporting scaffold and polymeric tubular shell (one or more membranes) of FIG. 4C after the integrated membrane / expandable scaffold has been radially expanded by a balloon from an as-delivered configuration to an expanded configuration.

[0170] [Figure 5A] FIG. 5A is a "unfolded" view of another embodiment of a support scaffold having helically arranged circumferential support rings constructed in accordance with the principles of the present invention.

[0171] [Figure 5B] FIG. 5B is a detailed view of adjacent circumferential support rings of the expandable distal tip of the support scaffold of FIG. 5A.

[0172] [Figure 6A] FIG. 6A is a "unfolded" view of a further embodiment of a support scaffold having helically arranged circumferential support rings constructed in accordance with the principles of the present invention.

[0173] [Figure 6B] FIG. 6B is a detailed view of adjacent circumferential support rings of the expandable distal tip of the support scaffold of FIG. 6A.

[0174] [Figure 7-1] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-2] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-3] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-4] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-5] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-6] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-7] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-8] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention. [Figure 7-9] 7A-7AR-2 illustrate various alternative embodiments of geometries, scaffolding designs, and connection locations and shapes for the support elements of the present invention.

[0175] [Figure 8] FIG. 8 is an “unfolded” view of a further embodiment of a support scaffold having adjacently linked circumferential support rings with different frequencies or numbers of crowns, gap widths, cell periodicities, cell amplitudes, and embodiments of differently configured support elements constructed in accordance with the principles of the present invention.

[0176] [Figure 9A] FIG. 9A is an unfolded view of an alternative embodiment of a support scaffold having helically arranged circumferential support rings without support elements, constructed in accordance with the principles of the present invention.

[0177] [Figure 9B]FIG. 9B is a detailed view of adjacent circumferential support rings of the expandable distal tip of the support scaffold of FIG. 9A.

[0178] [Figure 9C] FIG. 9C illustrates an alternative embodiment of a support scaffold of the present invention having discrete support pads (or islands) located between the struts of a serpentine support ring.

[0179] [Figure 10-1] 10A-10G illustrate an exemplary use of the system of FIG. 1 to advance and expand (deploy) an aspiration catheter within a patient's vasculature in accordance with the principles of the present invention. [Figure 10-2] 10A-10G illustrate an exemplary use of the system of FIG. 1 to advance and expand (deploy) an aspiration catheter within a patient's vasculature in accordance with the principles of the present invention.

[0180] [Figure 11A] Figure 11A is a detailed view of an expandable distal tip of an alternative embodiment of an aspiration catheter of the present invention having a support scaffold comprising multiple rings, shown in an unexpanded configuration with a portion of the covering membrane removed or destroyed. Figure 11 also shows a transition ring comprising an expandable section and a non-expandable section (in this embodiment, a coil). It also shows the expandable scaffold and the non-expandable coil formed continuously from the same tube or bent wire.

[0181] [Figure 11B] FIG. 11B is an "unfolded" view of the support scaffold at the expandable distal tip of the aspiration catheter of the system of FIG. 11A, showing the transition from the expandable scaffold at the distal tip to a non-expandable support scaffold formed as a helical coil within the body of the aspiration catheter.

[0182] [Figure 11C]Figure 11C is a detailed view of an individual cell of the support scaffold of the expandable distal tip of the aspiration catheter of the system of Figure 11A, showing the recessed support elements and the filled pattern configuration in the patterned (or delivered) configuration. Figure 11C also shows the arc length of the crown, which is approximately the same length as the axial length of the strut.

[0183] [Figure 11D] FIG. 11D is a close-up "unfolded" view of the support scaffolding of the expandable distal tip of the aspiration catheter of the system of FIG. 11A, showing details of the flush distal termination ring.

[0184] [Figure 11E] 11E and 11F are alternative detailed views of an embodiment of a transition region between an expandable scaffold supporting the distal tip of an aspiration catheter of the present invention and a fixed diameter reinforcing structural shaft region of the aspiration catheter of the present invention. [Figure 11F] 11E and 11F are alternative detailed views of an embodiment of a transition region between an expandable scaffold supporting the distal tip of an aspiration catheter of the present invention and a fixed diameter reinforcing structural shaft region of the aspiration catheter of the present invention.

[0185] [Figure 11G] 11G and 11H illustrate recessed and protruding cantilevered support elements of the present invention. [Figure 11H] 11G and 11H illustrate recessed and protruding cantilevered support elements of the present invention.

[0186] [Figure 11I] 11I and 11J illustrate example helical support structures comprising two and three nested continuous helical rings, respectively. [Figure 11J] 11I and 11J illustrate example helical support structures comprising two and three nested continuous helical rings, respectively.

[0187] [Figure 12A] 12A-12D illustrate the support scaffolding of the expandable distal tip of the aspiration catheter of FIGS. 11A-11C shown in an alternative expanded configuration (deployed). [Figure 12B] 12A-12D illustrate the support scaffolding of the expandable distal tip of the aspiration catheter of FIGS. 11A-11C shown in an alternative expanded configuration (deployed). [Figure 12C] 12A-12D illustrate the support scaffolding of the expandable distal tip of the aspiration catheter of FIGS. 11A-11C shown in an alternative expanded configuration (deployed). [Figure 12D] 12A-12D illustrate the support scaffolding of the expandable distal tip of the aspiration catheter of FIGS. 11A-11C shown in an alternative expanded configuration (deployed).

[0188] [Figure 12E] FIG. 12E illustrates a support scaffold similar to that shown in FIG. 12A shown in an unexpanded configuration with a reduced diameter tip to facilitate introduction over a guidewire with improved deliverability into the vasculature.

[0189] [Figure 13-1] 13A-13G illustrate the use of the system of FIG. 1A to advance and deploy the aspiration catheter of FIGS. 11A-11D within a patient's vasculature, in accordance with the principles of the present invention. [Figure 13-2] 13A-13G illustrate the use of the system of FIG. 1A to advance and deploy the aspiration catheter of FIGS. 11A-11D within a patient's vasculature, in accordance with the principles of the present invention.

[0190] [Figure 14A] 14A and 14B illustrate how a "pitch angle," as referred to herein, may be determined as an acute angle. [Figure 14B] 14A and 14B illustrate how a "pitch angle," as referred to herein, may be determined as an acute angle.

[0191] [Figure 14C] 14C-14E ​​illustrate distal tip support scaffolds with varying pitch angles and varying gap lengths between rings. [Figure 14D] 14C-14E ​​illustrate distal tip support scaffolds with varying pitch angles and varying gap lengths between rings. [Figure 14E] 14C-14E ​​illustrate distal tip support scaffolds with varying pitch angles and varying gap lengths between rings.

[0192] [Figure 15A] 15A-15C are detailed exemplary drawings illustrating different bending patterns that may be utilized within the radially expandable distal tip ring of the present invention. [Figure 15B] 15A-15C are detailed exemplary drawings illustrating different bending patterns that may be utilized within the radially expandable distal tip ring of the present invention. [Figure 15C] 15A-15C are detailed exemplary drawings illustrating different bending patterns that may be utilized within the radially expandable distal tip ring of the present invention.

[0193] [Figure 15D] 15D and 15E are side and perspective views of a radially expandable distal tip ring of the present invention having a repeating omega shaped cell pattern. [Figure 15E] 15D and 15E are side and perspective views of a radially expandable distal tip ring of the present invention having a repeating omega shaped cell pattern.

[0194] [Figure 16] FIG. 16 illustrates how the faceted outer surface of a radially expandable distal tip ring of the present invention approaches a circular circumference as a measure of circularity.

[0195] [Figure 17]FIG. 17 identifies various features that may be used to define the rings of the helical radially expandable distal tip scaffolding or structure of the present invention.

[0196] [Figure 18] 18A-18C show side, perspective, and "unfolded" views of an expandable scaffold comprising multiple laterally oriented, axially connected (or joined), expandable rings.

[0197] [Figure 19] FIG. 19 identifies various characteristics that can be used to define the structure of an expandable scaffold comprising multiple laterally oriented, axially linked (or joined), expandable rings, such as those shown in FIGS. 18A-18C.

[0198] [Figure 20A] 20A and 20B show side and "unfolded" views of an expandable scaffold comprising multiple parallel axially linked (or joined) expandable rings that are tilted relative to the longitudinal axis of the scaffold. [Figure 20B] 20A and 20B show side and "unfolded" views of an expandable scaffold comprising multiple parallel axially linked (or joined) expandable rings that are tilted relative to the longitudinal axis of the scaffold.

[0199] [Figure 21] FIG. 21 is a "unfolded" view of an expandable scaffold having compartments with in-phase and out-of-phase aligned cells.

[0200] [Figure 22] FIG. 22 is a "unfolded" view of an expandable scaffold comprising multiple rings with gaps between them having varying lengths.

[0201] [Figure 23A] FIG. 23A is an "unfolded" view of an expandable scaffold comprising multiple rings with gaps between them arranged in a helical pattern.

[0202] [Figure 23B] FIG. 23B is a detailed illustrative view of the rings of FIG. 23A showing that each ring has a serpentine pattern.

[0203] [Figure 23C] 23C-23E are rotated side views of the expandable scaffold of FIG. 23A. [Figure 23D] 23C-23E are rotated side views of the expandable scaffold of FIG. 23A. [Figure 23E] 23C-23E are rotated side views of the expandable scaffold of FIG. 23A.

[0204] [Figure 24A] FIG. 24A is an "unfolded" view of an expandable scaffold comprising multiple rings, with gaps between them, arranged in a spiral pattern, each ring having a first curved shape in the unfolded pattern.

[0205] [Figure 24B] FIG. 24B is a detailed view of the rings of FIG. 24A showing that each ring has a serpentine pattern.

[0206] [Figure 24C] 24C-24E are rotated side views of the expandable scaffold of FIG. 24A. [Figure 24D] 24C-24E are rotated side views of the expandable scaffold of FIG. 24A. [Figure 24E] 24C-24E are rotated side views of the expandable scaffold of FIG. 24A.

[0207] [Figure 25A] FIG. 25A is an "unfolded" view of an expandable scaffold comprising multiple rings arranged in a spiral pattern with gaps between them, each ring having a second curved shape in the unfolded pattern.

[0208] [Figure 25B]FIG. 25B is a detailed illustrative view of the rings of FIG. 25A showing that each ring has a serpentine pattern.

[0209] [Figure 25C] 25C-25E are rotated side views of the expandable scaffold of FIG. 25A. [Figure 25D] 25C-25E are rotated side views of the expandable scaffold of FIG. 25A. [Figure 25E] 25C-25E are rotated side views of the expandable scaffold of FIG. 25A.

[0210] [Figure 26] FIG. 26 is a "unfolded" view of a ring pattern with S-shaped expandable elements joined by non-extensible circumferential links shown prior to expansion.

[0211] [Figure 27] FIG. 27 is an "unfolded" view of a ring pattern with bent wires having integrated cantilevered support elements.

[0212] [Figure 28] 28A and 28B are "unfolded" views of the closed cell box ring pattern shown in its unexpanded and expanded configurations, respectively.

[0213] [Figure 29] 29A and 29B are "unfolded" views of the closed cell box ring pattern shown in its unexpanded and expanded configurations, respectively, further comprising cantilevered support elements recessed between circumferentially adjacent box elements in the unexpanded configuration.

[0214] [Diagram 30]30A and 30B are "unfolded" views of an alternative closed cell box ring pattern shown in its unexpanded and expanded configurations, respectively, which further comprises cantilevered support elements recessed between circumferentially adjacent box elements in the unexpanded configuration.

[0215] [Diagram 31] 31A-31C illustrate an exemplary method for embedding a radially expandable support scaffold or other structure within a polymeric membrane.

[0216] [Diagram 32] FIG. 32 is a cross-sectional view of a distal tip region fabricated by the method of FIGS. 31A-31C shown in a radially expanded configuration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0217] Detailed Description of the Invention 1, a system 10 for removing blood clots from a patient's vasculature, typically the cerebral vasculature, comprises an aspiration catheter 12 and a distal tip dilation catheter 14, typically an inflatable balloon catheter. The aspiration catheter 12 has an expandable distal tip 18 at the distal end of a tubular body 22 and a proximal hub 20 at the proximal end of the tubular body. The tubular body 22 has an aspiration lumen extending from its distal end to its proximal end, with a luer fitting / connector 24 configured to be attached to a syringe or other vacuum or negative pressure source of the type typically found in a hospital or other medical treatment facility. By applying negative pressure to the luer fitting / connector 24, blood clots can be aspirated into the open distal end of the expandable distal tip 18, as described in more detail below. The drawings of system 10 show a proximal hub 20 having a luer fitting / connector 24 that is connected to a guidewire lumen (not shown), which in this embodiment is also the same lumen as the aspiration lumen. The guidewire is typically removed prior to attaching luer fitting / connector 24 to a vacuum pump to maximize aspiration power. In another embodiment, system 10 may be adapted to have a proximal hub similar to proximal hub 30, in which luer fitting / connector 32 would be connected to a guidewire lumen (not shown), while luer fitting / connector 34 would be connected to a vacuum pump.

[0218] The distal tip dilatation catheter 14 includes a balloon or other expandable member 26 at the distal end of a shaft 28. A proximal hub 30 is attached to the proximal end of the shaft 28 and includes a first luer connector 32 and a second luer connector 34. The first luer connector 32 is connected to a guidewire lumen (not shown), which extends the entire length of the shaft 28, allowing the catheter 14 to be advanced over a guidewire or microcatheter to a target location within the patient's brain or other vasculature. The second luer connector 34 is configured to connect to a balloon inflation lumen (not shown) within the shaft 28, which allows the expandable distal tip 18 of the aspiration catheter 12 to expand adjacent a target clot within the patient's vasculature, as will be described in more detail below.

[0219] 1A illustrates a second exemplary suction catheter 112 suitable for use with the distal tip dilatation catheter 14 of FIG. 1. The suction catheter 112 has a similar structure to that of the suction catheter 12, including an expandable distal tip 118 at the distal end of a tubular body 122 and a proximal hub 120 at the proximal end of the tubular body. The tubular catheter body 122 has an aspiration lumen extending from its distal end to its proximal end, and a luer fitting 124 at the proximal end of the tubular body 122 is configured to be attached to a vacuum pump or negative pressure source of the type typically found in a hospital or other medical treatment facility. By applying negative pressure to the luer fitting / connector 124, blood clots engaged at the distal tip can be aspirated into the open distal end of the expandable distal tip 118, as described in more detail below. The drawing of the suction catheter 112 shows a proximal hub 120 having a luer fitting / connector 124 that is connected to a guidewire lumen (not shown), which in this embodiment is also the same lumen as the suction lumen. The guidewire is typically removed prior to attaching the luer fitting / connector 24 to a vacuum pump. In another embodiment, the suction catheter 124 may be adapted to have a proximal hub similar to the proximal hub 30 of FIG. 1, in which the luer fitting / connector 32 would be connected to the guidewire lumen (not shown), while the luer fitting / connector 34 would be connected to a vacuum pump.

[0220] In contrast to the aspiration catheter of FIG. 1, the expandable scaffold 118 of the aspiration catheter 112 is typically connected or attached or joined at its proximal end to a non-expandable reinforcing structure, such as a coil 128, typically a helical ribbon, which may be formed integrally (or continuously) with the helical expandable scaffold 118. The reinforcing coil 128 may be formed from the same balloon-expandable scaffold material (e.g., malleable metal, including metal or metal alloy) as the expandable scaffold at the distal tip 118, but the reinforcing coil will not typically be radially expandable by a distal tip expansion catheter (such as a balloon catheter) because the reinforcing coil is not configured with a wavy pattern, including bends and struts, or otherwise to allow for radial expansion, as described in more detail herein below. In some cases, the reinforcing coil 128 will typically have the same thickness as the thickness of the expandable scaffold at the distal tip 118. Similarly, the reinforcing coil 128 will typically have an absolute pitch angle similar to the pitch angle of the expandable scaffold, preferably ranging from 80° to 89.9° relative to the longitudinal axis in the as-patterned or as-delivered configuration. In some other cases, the reinforcing coil 128 will have an absolute pitch angle ranging from 70° to 89.9°, preferably ranging from 80° to 89.9°, relative to the longitudinal axis in the as-patterned or as-delivered configuration. In some cases, the reinforcing coil 128 will typically have a width ranging from approximately the same width as the expandable rings of the expandable scaffold to three times the width of the expandable rings of the expandable scaffold at the expandable tip 118. In some other cases, the reinforcing coil 128 will have a width ranging from 0.05 mm to 0.25 mm and a gap ranging from 0.025 mm to 0.25 mm. In some embodiments, the gap between the coils is fixed. In other embodiments, the gap between the coils is variable. In some cases, the reinforcing coil 128 is integrally formed from the same tube or bent wire that forms the expandable scaffolding of the expandable tip 118. The tube or bent wire is patterned to form multiple adjacent ribbons, rings, or turns that are continuously joined end-to-end in a helical arrangement, typically patterned by a laser, bent wire, or other means.In other cases, the reinforcing coil 128 is formed from a bent wire to form a plurality of adjacent turns joined end-to-end in a helical arrangement. In this example, the expandable scaffold of the expandable tip 118 is formed from the same tube as the coil 128, the expandable scaffold is formed from a tube patterned to form a plurality of adjacent rings joined end-to-end in a helical arrangement, each ring comprising structural elements with struts joined by crowns, the expandable coil scaffold having an absolute pitch angle ranging from 70° to 89.9°, or preferably ranging from 80° to 89°. For example, the distal tip expandable scaffold 118 may be encased in an expandable membrane comprising one or more membranes, which may be elastic and / or inelastic, but stretchable, membranes (allowing expansion) that cover the expandable scaffold 118 and extend from the distal end of the distal tip to at least the proximal end of the expandable scaffold. In some cases, the expandable membrane extends proximally to the proximal end of the expandable scaffold and covers at least a section of the reinforcing coil 128, or in some cases extends proximally and covers substantially the entire length of the reinforcing coil 128, while in certain other cases the reinforcing coil 128 may be coated with one or more elastic and / or inelastic (resistant to expansion) membranes that are different from the one or more membranes that cover the expandable scaffold 118. In some cases, the one or more expandable membranes that cover the expandable scaffold are attached to the inner and / or outer surface of the expandable scaffold. In other cases, the expandable scaffold is laminated to, embedded in, or coated by one or more expandable membranes that cover the outer surface and / or cover the inner surface of the expandable scaffold. In some cases, the expandable scaffold is covered by at least two membranes, one membrane attached to an outer surface of the expandable scaffold and another membrane attached to an inner surface of the expandable scaffold.In other cases, the aspiration catheter comprises an expandable tip, the expandable tip comprising an expandable membrane and an expandable support structure, such as a scaffold, the expandable scaffold comprising a plurality of rings spaced apart along a longitudinal axis with gaps between them and within each of the rings, the rings comprising structural elements comprising struts and crowns, the expandable scaffold being embedded in or within one or more expandable membranes covering the scaffold, the expandable membrane comprising at least one membrane softened and / or melted over an outer surface of the expandable scaffold and / or over an inner surface of the expandable scaffold, allowing the one or more expandable membranes to soften or melt and protrude or flow into gaps present within each ring (each ring structural element) and between the rings, the material adhering to the rings (ring structural elements) to provide an integrally expandable scaffold / membrane system, expandable from a contracted or delivery configuration to a larger expanded configuration. The expandable membrane, in preferred aspects, covers the exterior and / or interior surface of the expandable support structure or scaffold and covers at least some of the gaps present within each ring of the expandable scaffold and gaps present between adjacent rings of the expandable scaffold, wherein the covering comprises one or more of: coating, providing a fluid seal at, filling, flowing into, flowing onto, or protruding into, or adhering to, embedded in, or laminated to the exterior surface of the scaffold, the interior surface of the scaffold, and / or gaps between the exterior and interior surfaces of the scaffold, wherein the covering membrane sufficiently adheres to the scaffold ring structural elements to provide an integrated system capable of cooperatively expanding as an integrated system from a delivered configuration to an expanded configuration.The expandable membrane, in preferred aspects, covers at least a portion, preferably covers a majority, and most preferably covers all of, i.e., flows into gaps present between each of the rings in each of the ring structural elements comprising struts joined by crowns, and one or more expandable membranes, in preferred aspects, cover the exterior and / or interior surface of the expandable scaffold, cover at least some side surfaces of the expandable scaffold structural element, preferably cover substantially all side surfaces of the expandable scaffold structural element, and cover substantially all gaps between adjacent rings of the expandable scaffold. The expandable scaffold, in preferred aspects, comprises an exterior surface, an interior surface, and two side surfaces. In other aspects, the expandable scaffold is formed from a bent wire comprising an exterior surface and an interior surface. In certain other cases, the reinforcing coil material 128 may be formed of a different material than the expandable scaffold material 118, for example, formed of a shape memory metal material or formed of other malleable metal or metal alloy material, and then attached to the expandable scaffold proximal end by soldering, or by abutting or interlacing (nesting or interleaving) the two material ends and covering and holding them together with one or more membranes. The one or more membranes covering the coil 128 can be the same as the one or more membranes covering the expandable scaffold 118. In another example, at least one membrane covering the coil 128 is the same membrane that covers the expandable scaffold 118, typically with at least the inner surface membrane covering both the expandable scaffold 118 and the reinforcing coil 128. The expandable coil scaffold 118 may be formed from a tube forming a plurality of circumferentially expandable rings, including struts, including structural elements, joined by crowns. Similarly, the reinforcing non-expandable coil 128 may also be formed from the same tube forming a helical ribbon. The expandable scaffold rings, structural elements, struts, and crowns, and the helical ribbon of the reinforcing coil each have an outer surface, an inner surface, and at least two side surfaces.In other embodiments, the expandable coil scaffold and the reinforcing non-expandable coil may alternatively be formed from bent wire to form the expandable coil 118 and the reinforcing coil 128.

[0221] The catheter body 122 includes two additional regions: an intermediate region 130, typically reinforced with a helical ribbon, and a proximal region 132, typically reinforced with a braid. The intermediate region 130 will have an "intermediate" flexibility between that of the flexible regions 118 and 128 and that of the stiffer and more pushable proximal region 132. The distal end of the proximal region 132 is connected to the proximal end of the intermediate region 130 by overlapping their ends and covering the joint 1A-1 with a first adhesive jacket 140, the adhesive jacket comprising one or more films that are heated sufficiently to soften and / or melt the material, which flows into or protrudes into the metal structure gaps sufficiently to adhere to the metal structure and hold the two structures, regions, or sections together, and the distal end of the intermediate region 130 is connected to the reinforcing coil 128 by nesting their ends (intertwining their ends) and covering the joint 1A-2 with a second adhesive jacket 142, the adhesive jacket comprising one or more films that are heated sufficiently to soften and / or melt the material, which flows into or protrudes into the metal structure gaps sufficiently to adhere to the metal structure and hold the two structures, regions, or sections together. The adhesive jackets may be the same or different. 1A-1 and 1A-2, the outer adhesive jackets 140 and 142 typically overlap some nested or intertwined coils at the coiled region junction 1A-2 or at a section longer than junction 1A-2, or overlap a distance, preferably a short distance, above the overlapped junction 1A-1 of the coiled region / braided region of the proximal region 132. The intermediate region 130 is typically formed integrally with or continuous with the regions 128 and 118, and is typically a helical coil having a different pitch angle, width, and gap from the helical coil of the region 128, configured to provide better pushability. In other embodiments, the regions 128 and 130 are formed to have the same pitch angle, width, and gap between the coils, and the combined regions 128 and 130 are spliced ​​to the braided proximal shaft 132.In yet another embodiment, the intermediate region 130 is formed from a different metal, e.g., a shape memory metal or metal alloy, e.g., Nitinol, and is formed as a coil with a pitch angle, coil width, and gap between the coils to improve the flexibility and pushability of the intermediate region 130. The expandable scaffold of region 118 is preferably formed from a tube, but can also be formed from a bent wire. Region 128 is preferably formed from the same tube that forms the expandable region 118 in an integrated manner. Region 130 is typically formed from the same tube that forms region 128 and / or region 118, but can also be formed from a different material or tube or bent wire. In a preferred embodiment, the expandable scaffold of region 18 is patterned from a tube that forms a structural element having an outer surface, an inner surface, and a side surface, the structural element comprising struts joined by crowns to form a plurality of adjacent rings expandable from a crimped configuration to an expanded configuration. Regions 128 and 130 are preferably formed from a tube, preferably the same tube, and in an integrated manner form expandable scaffold region 118, with region 128 formed in the form of a helical coil. The reinforcing structure is typically a coil, although other types of reinforcing structures, e.g., scaffolds, support scaffolds, may be substituted for the coils in region 128, and are typically formed contiguous with the expandable support scaffold of region 118. In other cases, region 118 may be formed from a shape memory alloy, e.g., a nickel titanium alloy, and is constrained in a delivery configuration before being released to expand from the delivery configuration to the expanded configuration.

[0222] FIG. 1B illustrates the system of FIG. 1 as it is introduced to a target location with a clot C in the cerebral vasculature CV via the femoral artery FA. A guidewire GW is introduced through a sheath (not shown) into the femoral artery FA. The aspiration catheter 12 of FIG. 1 or FIG. 1A is introduced over the guidewire GW and advanced through the guiding catheter and / or guiding sheath (not shown) through the femoral artery FA, ​​through the aorta A, e.g., into the target cerebral artery CA until the expandable distal tip 18 is positioned adjacent to or engages the target clot C. The distal tip dilation catheter 14 is then advanced over the guidewire, through the hemostatic valve HV, and the expandable member 26 is advanced until it is located within the expandable distal tip 18. The expandable member 26 is then expanded, typically by inflation, to expand the distal tip 18 so that its outer surface generally engages the clot and / or seals against and / or expands toward the inner wall of the cerebral artery at a location adjacent the clot C. The geometry of the expanded distal tip 18 can be varied, as described hereinafter, and the catheter 14 is then removed, and in all cases a vacuum pump or negative pressure will be applied through the proximal hub 20 to pull the clot C into the aspiration catheter 12 so that it may be removed from the vasculature.

[0223] 2A-2C, the structure of the expandable distal tip 18 of the aspiration catheter 12 in FIG. 1 will be described in further detail. The expandable distal tip 18 includes both an expandable support scaffold 38 and an expandable membrane 40. As described above, the expandable membrane 40 will typically comprise one or more of an elastic or extensible inelastic polymer membrane with the support scaffold 38 embedded or laminated therein and covering the scaffold. The support membrane typically flows, protrudes or otherwise adheres to the support scaffold structural element to provide an integrated expandable scaffold membrane system. The support scaffold 38 typically comprises a metal or metal alloy, typically formed from a malleable metal or metal alloy, and the scaffold is configured for balloon expansion, but may otherwise be configured for self-expansion after release from restraint.

[0224] The support scaffold 38 includes a plurality of radially expandable circumferential support rings 42, each ring separated from an adjacent ring by a gap. The rings typically include a wavy pattern, e.g., a serpentine, box, or zigzag pattern, including struts 48 joined by crowns 50, and adjacent rings 42 may be connected by one axial link 46. While the support scaffold 38 shows a vertical ring having approximately 90° relative to the longitudinal axis, the support scaffold 38 may alternatively be formed of a plurality of rings having an acute pitch angle, the pitch angle preferably ranging from 70° to 89.9° relative to the longitudinal axis when patterned or configured for delivery (not shown). In a preferred embodiment, adjacent rings are joined by one link, or no more than one link, or no more than two links (not shown). The links can have a variety of shapes, e.g., offset linear (as shown) or other types of shapes linear or non-linear, e.g., U, M, Z, S, or other shapes. In another example (not shown), at least some adjacent rings are not joined together, but are held together by a membrane that covers, is affixed onto, is coated over, or is melted over at least some of the rings, allowing the rings to be held together in the as-delivered configuration and to expand from the as-delivered configuration to the expanded configuration. Adjacent rings are typically joined by one or more connections, but alternatively, sometimes structural elements on adjacent rings are soldered or fused or otherwise attached together to join adjacent rings in one or more locations. Alternatively (not shown), the support scaffold 38 may be formed from an expandable coil comprising a plurality of adjacent expandable rings (or turns) joined end-to-end in a helical arrangement, each ring comprising structural elements including struts joined by support elements and crowns, the expandable coil having an acute pitch angle relative to the longitudinal axis in the patterned or delivered configuration ranging from 70° to 89.9°, preferably ranging from 80° to 89°.The expandable rings of the expandable coil of the support scaffold are joined end-to-end in a helical arrangement and typically are not otherwise joined (such as by a link or by attaching a structural element or attachment point on an adjacent ring). In some limited cases, at least some of the rings of the expandable coil may be joined by one or more links or by attaching a structural element on an adjacent ring, typically on a ring at the proximal end of region 118 of FIG. 1A, to provide support. In a preferred embodiment, the expandable coil is expanded from an as-delivered or contracted configuration to an expanded configuration by an expandable support structure radially expanded within the interior of the expandable coil, e.g., a balloon catheter, and the expandable coil is said to be balloon expandable. Alternatively, the support scaffold may be formed from a bent wire forming a plurality of adjacent turns joined end-to-end in a helical arrangement. The expandable coil may be formed from a tubular body and patterned into the expandable coil with a plurality of circumferentially expandable rings. In preferred embodiments, gaps exist between at least some of the rings of the expandable scaffold, and preferably gaps exist between all adjacent rings of the expandable scaffold. As shown in these figures, the gaps between adjacent rings are typically fixed (FIGS. 2A, 2B, and 2C), although in some cases the gaps may have a variable axial length (not shown).

[0225] In an exemplary embodiment of the invention, the support elements 52 of the expandable scaffold 38 are located between adjacent pairs of struts 48 and have a base end 56 attached to the inner radius of the crown 50, which joins the adjacent support members facing opposite axial directions to the struts. In this manner, the support elements 52 reinforce the region of the expandable membrane 40 that spans the struts 48. Furthermore, the support element 52 length, in this preferred embodiment, is equal to or less than the ring period, thereby not extending into the interstitial region between adjacent rings (as shown). This improves the deliverability of the scaffold and reinforces the region of the expandable membrane. The support element 52 length is greater than 1 / 2 the length of adjacent struts, which is equal to or less than the adjacent ring period (as shown). This provides balance between the reinforced regions of the expandable membrane and improves the deliverability of the scaffold. The support elements 52, in this embodiment, have an axial length, a base, and a free end that terminates at or prior to the beginning of the gap region between the rings (as shown). In more rare cases, the support element length may extend beyond the peak of the adjacent crown and into the gap region between the rings (not shown). In this preferred embodiment, the support elements 52 in each ring have the same length. In this preferred embodiment, the support elements 52 in at least some of the rings or within the entire length of the scaffold have the same length (as shown). However, the support elements in a ring may have different lengths (not shown), or the support elements on adjacent rings may have different lengths (not shown), or the support elements on at least some of the rings are different (not shown). In some embodiments, the width of the support elements 52 is the same within each ring and also within multiple rings (as shown). However, the width of the support elements may vary within a ring or within multiple rings (not shown). In a preferred embodiment, the width of the support element 52 is approximately the same as the width of an adjacent structural element, e.g., an adjacent crown or column. Alternatively, the width of the support element 52 is equal to or greater than the width of an adjacent structural element, e.g., an adjacent crown or column. In yet another embodiment, the width of the support element 52 is greater than the width of an adjacent structural element, e.g., an adjacent crown or column.In yet other embodiments, the width of the support element 52 is less than the width of an adjacent structural element, e.g., adjacent crown or strut. In some cases, the width along the length of the support element or along the structural element, e.g., strut or crown, may vary. In such embodiments, the width is the average of the maximum and minimum widths of the support element or along the length of the structural element. The support elements 52 each have a base end 56 that is attached / connected to the radially expandable circumferential support ring 42. The base ends 56 typically have the same width as the rest of the support element (as shown), although in other embodiments, the base may have a width greater than the support element width. The support elements each have a free end 58 that extends into the area between adjacent struts. The free ends 58 may have a rounded shape (as shown), or in other embodiments, a flat shape (not shown), a T-shape (not shown), or other shapes or configurations. Although the support elements 52 are shown attached to the inner radius or wall of the crown 50 and are linear, in other embodiments the support elements are attached elsewhere on the support ring 42, e.g., attached to struts, and may be linear or non-linear. In this embodiment, at least some of the support elements are connected to each radially expandable circumferential support ring 42. In this embodiment, at least some of the support elements are connected to at least some of the radially expandable circumferential support rings 42. In this embodiment, at least some of the support elements are connected to substantially all of the radially expandable circumferential support rings 42. In this embodiment, at least some of the radially expandable circumferential support rings, each ring comprising a plurality of cells, each cell comprising struts joined by a crown, and at least one support element is connected to each cell on at least some of the expandable rings (as shown). In this embodiment, at least one radially expandable circumferential ring, the ring comprising a plurality of cells, each cell comprising struts joined by a crown, and at least one support element is connected to each cell on the expandable ring (as shown).In this embodiment, at least one radially expandable circumferential ring, the ring comprising a plurality of cells, each cell comprising struts joined by crowns, and at least some of the support elements connected to at least some of the cells on the expandable ring (as shown in FIG. 2C). In this embodiment, at least some radially expandable circumferential support rings, the ring comprising a plurality of cells, each cell comprising struts joined by crowns, and at least some of the support elements connected to at least some of the cells on the expandable ring (as shown). Various attachment locations and support member geometries are described with reference to FIGS. 7A-7AR-2 herein below.

[0226] Typically, but not necessarily, the support scaffold 38 will be laser cut from a metal tube, for example in a "unrolled" pattern as shown in FIG. 2B. The pattern includes a helical coil 44 (helical coil 128 in FIG. 1A) patterned continuously from the same tube that formed the expandable scaffold, the helical coil 44 intended to support at least a portion of the one or more membranes 22, as best seen in FIG. 2A. The reinforcing coil has a length ranging from 1 mm to 100 cm, preferably ranging from 1 cm to 50 cm, more preferably ranging from 1 cm to 25 cm. The reinforcing coil has an acute pitch angle, width, and thickness as discussed above. The helical coil will have gaps between the coils ranging from 0.01 mm to 0.25 mm. The one or more membranes 22 may be the same or different from the one or more expandable membranes 40. In one embodiment, the at least one membrane 40 extends from the distal end of the distal tip to a proximal region, which is approximately the proximal end of the coil 44. In another embodiment, the at least one membrane 22 is formed, coated, or covers at least a portion of the coil length, preferably covering the entire length of the coil 44. In this case, the membrane 22 is formed from a stiffer material to provide improved support (reinforcement) to the coil region 128 of FIG. 1A. The at least one membrane 22 and the at least one membrane 44 would typically be spliced, fused, or attached (as shown) at the interface of the expandable scaffold 38 and the reinforcing coil 44 in this case. The reinforcing coil 44 may have a length to extend the entire length of the tubular body 122 of FIG. 1A, but more typically will extend only over a shorter transition region at the distal end of the tubular body. The proximal portion of the tubular body 122 may typically have a braid or other form of reinforcement.

[0227] As shown in Figures 1 and 2A-2C, the expandable distal tip 18 and the support scaffold 38 of the aspiration catheter are in their unexpanded configuration (or delivery configuration), which is suitable for introduction through the patient's vasculature to the target clot location. Also, as shown in Figure 2A, the expandable scaffold 38 and the reinforcing coil 44 connected to the proximal end of the expandable scaffold have the same inner and / or outer diameter, or have the same configuration, delivery configuration, to facilitate introduction through the patient's vasculature. Alternatively (not shown), the expandable scaffold section 38 can have a delivery configuration that is smaller than the delivery configuration of the reinforcing coil section connected to the proximal end of the scaffold, to improve the deliverability of the aspiration catheter. However, once at the target clot location, the expandable distal tip 18 and the support structure 38 will expand and engage the clot or the wall of the blood vessel adjacent to the clot, as described in more detail with reference to Figures 10A-10G herein below. The support elements in Figures 2A-2C, comprising at least one support element contained within each cell on a ring or contained within at least some cells on a ring, form a circumferential shell around the scaffold circumference along a scaffold length or along the entire length of the scaffold. The circumferential shell typically has a fixed axial length, width, shape, number of support elements per ring, pitch angle, and / or geometry (as shown) and expands from an as-delivered configuration to an expanded configuration, providing support to one or more expandable membranes and resisting collapse of the one or more expandable membranes after a vacuum is applied to the proximal end of the aspiration catheter and the distal tip is blocked or plugged with a clot or other material. In this example, the support elements are contained within each cell on a ring or within each ring amplitude, preferably within the spaces of struts joined by crowns on the same ring, the amplitude comprising the axial distance between two adjacent peaks on the same ring.In some cases, the support elements may have varying lengths, widths, shapes, missing support elements (one or more cells in a ring have no support elements), pitch angles, and / or geometries within a ring or along at least some of the rings, where the different widths, lengths, shapes, missing support elements, or geometries maintain sufficient support for the expandable one or more membranes and, in the expanded configuration, prevent collapse of the at least one or more membranes under vacuum if the distal tip becomes blocked or embolized with a blood clot or other material.

[0228] As shown in Figures 3A-3D, the expandable distal tip 18 (shown without an expandable membrane) may be expanded into a variety of different geometries. In many cases, the expanded geometry will be generally cylindrical 38a, as shown in Figure 3A, or may have a conical tip terminating in a generally cylindrical distal end (not shown). In other cases, the expanded geometry may be generally conical 38b, with the base of the cone forming an enlarged distal opening for receiving the clot, as shown in Figure 3B. In still other cases, the expanded geometry may combine expanding and tapering conical sections 38c and 38d, as shown in Figures 3C and 3D. Typically, the different expansion geometries will be imparted by the shape of the expandable balloon 26, i.e., the support scaffold 38 will be malleable and will assume the expanded shape of the expansion balloon. In other cases, however, the support scaffold 38 may also be elastic or superelastic, such as those shown in Figures 3A-3D, and may be preformed by heat treatment or otherwise into the desired expanded geometry when unconstrained.

[0229] Now referring to FIG. 3E, in some cases, the unexpanded or delivery diameter (configuration) of the support scaffold 38e may be reduced to facilitate initial introduction over the guidewire. In particular, the support scaffold 38e may have an unexpanded (delivery) reduced diameter (configuration) relative to the coil support region 44e diameter (configuration), which represents the diameter (configuration) of the tubular body (not shown). As shown in FIG. 3A-3D, the proximal end of the expandable scaffold is typically connected continuously to form a non-expandable support structure, such as a coil (as shown in FIG. 3A-3D), a helical coil (as shown in FIG. 3E), or a non-expandable scaffold (not shown), or other support or reinforcing structure (not shown). As shown in FIG. 3A-3E, the distal end or turn of the reinforcing coil is connected to the proximal end ring of the expandable scaffold on the crown peak (as shown). Alternatively (not shown), the distal end of the reinforcing coil may be connected to the proximal end ring in at least one location, at least two locations, or at least three locations, where the locations on the ring may be on the crown peaks, on the crown troughs, and / or on the struts. The distal end of the reinforcing coil may typically be connected to the proximal end ring of the expandable scaffold by an axial link (as shown). The axial link may be linear, non-linear, offset, or have a variety of shapes, e.g., U, M, W, Z, or S. Alternatively, the distal end of the coil may be connected to one or more locations on the proximal end ring without a direct link (not shown). In this example, the reinforcing coil has an acute pitch angle of about 90° relative to the longitudinal axis in the patterned or delivered configuration. Alternatively, the pitch angle may alternatively range from 70° to 89.9° relative to the longitudinal axis in the patterned or delivered configuration. The reinforcing coil in Figures 3A-3D shows the reinforcing coil turns not connected by links. In certain other embodiments, the reinforcing coil may have one or more links connecting at least some adjacent turns of the coil and improving support of the reinforcing coil region. Alternatively, at least some adjacent turns may be joined by solder points on the adjacent turns or by other means.3A-3E show an expandable scaffold comprising expandable rings, where adjacent rings are connected by at least one link. In an alternative embodiment (not shown), the expandable scaffold of 3A-3E may be formed from circumferentially expandable rings, where at least some adjacent rings are not joined or are otherwise connected (by links or other means) and the adjacent rings are held together by one or more membranes that laminate the expandable scaffold between layers of tubular membrane. In a preferred embodiment, the distal end ring of the expandable scaffold preferably has flush ends and a pitch angle of about 90° relative to the longitudinal axis in the as-patterned or as-delivered configuration (as shown). In some other embodiments (not shown), the distal end ring of the expandable scaffold may have a tapered end. The tapered end ring may be configured by controlling the pitch angle on the end ring and / or by increasing the amplitude of at least some of the cells (or decreasing the amplitude of at least some of the cells) to achieve a desired distal end taper. The end rings may have the same cell amplitude, cell period, and / or cell width on at least some of the cells in the end ring, or may have different cell amplitudes, different cell period, and / or different cell widths on at least some of the cells in the end ring.

[0230] 4A-4D, the support scaffold 60 pattern includes support elements 68 attached to the outer curved walls of the crowns 66 that join adjacent struts 64. In contrast to the pattern of FIGS. 2A-2C, the support elements 68 do not extend between adjacent struts 64, but rather extend into the gaps or open spaces between adjacent radially expanding circumferential support rings 62. The second difference is that the support rings 62 are joined continuously end-to-end to form a helical pattern. FIG. 4C is an image showing the expandable region of the aspiration catheter, with the scaffold pattern of FIGS. 4A and 4B in a radially constricted configuration (or as-delivered configuration) suitable for delivery. FIG. 4D is an image of the same structure shown in FIG. 4C after it has been balloon expanded to an expanded configuration, preferably its fully expanded configuration suitable for aspiration. The distal end ring is configured (as shown) to have flush ends with an approximately 90° pitch angle relative to the longitudinal axis in the as-patterned or as-delivered configuration. The end and immediately adjacent rings may be configured in a variety of ways. The ring adjacent to the end ring is truncated and connected to the end ring along its circumferential path, as shown in FIG. 4A in this embodiment. The end ring and the ring adjacent to the end ring may have different acute (or 90°) pitch angles (as shown). Alternatively, the pre-end and end rings may also have the same or different cell amplitudes, cell periodicity, structural element widths, and / or number of crowns. The expandable scaffold 60 pattern has a pitch angle of about 86°. The pitch angle may range from 70° to 89.9°, preferably 80° to 89°, relative to the longitudinal axis in the as-patterned or as-delivered configuration in other embodiments. It is important to note that even if the support elements extend into the interstitial regions (or other spaces) between adjacent rings, these support elements typically do not extend into the adjacent ring regions, thereby maintaining enhanced deliverability of the expandable scaffold section into the vascular anatomy.

[0231] 5A and 5B, a support scaffold 70 having a helical pattern similar to that of scaffold 60 comprises multiple radially expandable circumferential support rings 72 including struts 74 and crowns 76. Support elements 78 differ from support elements 68 in that they have bifurcated end support disks. The support elements form a circumferential contour around the scaffold circumference along a scaffold length or along the entire length of the scaffold. The circumferential contour typically has a fixed axial length, width, shape, and / or geometry (as shown) and expands from an as-delivered configuration to an expanded configuration to provide support to and resist collapse of the one or more expandable membranes after a vacuum is applied to the proximal end of the aspiration catheter and the distal tip is blocked or plugged with a clot or other material. In this example, the support element base is at the crown peak region. The support elements extend axially over each ring amplitude or over at least some of the ring amplitudes, where the amplitude is the axial distance between two adjacent peaks on the same ring. In some cases, the support elements may have varying lengths, widths, shapes, or geometries within the ring or along at least some of the rings, and the different widths, lengths, shapes, or geometries continue to provide support to the expandable one or more membranes under vacuum and prevent collapse in the expanded configuration of at least one or more membranes. As shown in Figures 5A, 4A, and 6A, the proximal end ring of the expandable scaffold consists of an expandable section (shown) and a non-expandable section (truncated), defining the transition between the expandable scaffold and the reinforcing coil. The first non-expandable reinforcing coil section may be attached to one or more locations on an adjacent expandable ring and / or adjacent reinforcing coil turns, or may remain unjoined except for being joined to adjacent turns in a helical pattern.

[0232] 6A and 6B, support scaffold 80 comprises multiple radially expandable circumferential support rings 82 including struts 84 with helical patterns similar to those of scaffolds 60 and 70 and joined by crowns 86. Support elements 88 differ from support elements 68 and 78 in that they extend primarily in the circumferential direction, allowing adjacent support rings 82 to be positioned very closely together axially prior to expansion. In this embodiment, the support elements extend into substantially the entire gap between the rings, leaving small gaps between adjacent rings. This type of support element configuration provides one or more membranes with improved resistance to collapse when the membrane is expanded from the delivery configuration to the expanded configuration and a vacuum is applied to the proximal end of the aspiration catheter. On the other hand, such design configurations with small gaps are more suitable for biological structures that are not tortuous. In this and other embodiments, it is important to note the symmetry of the support elements within each ring, preferably within at least some of the rings, and more preferably along substantially the entire length of the scaffold. Such symmetry provides resistance to deformation and / or kinking when navigating the vasculature. It also provides improved resistance to expandable membrane collapse. In some cases, one or more support elements may be missing within one or more rings, providing an asymmetric support element pattern but maintaining resistance to expandable membrane collapse.

[0233] As previously shown, the support elements generally comprise linear structures having base ends attached to radially expandable circumferential support rings and free ends located in the spaces between adjacent struts, joined by crowns, or gaps between adjacent support rings. However, as shown in Figures 7A-7N, the geometry and attachment locations of the support elements may vary widely. As shown in Figure 7A, support element 104a has a base end attached to the inner radius or wall of crown 102 and a free end terminating in an oval contact pad 105a in the V-shaped, ω-shaped space between adjacent struts 100. The oval contact pad 105a has a major axis that is axially aligned. As shown in Figure 7B, support element 104b terminates in an oval contact pad 105b with a major axis that is circumferentially aligned.

[0234] Support element 104c in Fig. 7C is similar to the previously described support elements except that it terminates in a triangular contact pad 105c with a sharp tip oriented away from the attached crown. Support element 104d in Fig. 7D is similar to all of the previously described support elements except that it terminates in a triangular contact pad 105d with an enlarged base oriented away from the attached crown. Support element 104g shown in Fig. 7G has a base that is attached to the center of the inner wall of crown 102 and a circular contact pad 105g with a hole in its center that is circumferentially aligned with the attachment point.

[0235] Support elements with curved shafts are shown in Figures 7E, 7F, 7H, and 7I. Support element 104e shown in Figure 7E has an S-shaped shaft with a base end attached on one side of the outer curve of crown 102 and a circular contact pad 105e circumferentially aligned with the outermost point of the crown. Support element 104f shown in Figure 7F has a base attached to the outermost point on crown 102 and a circular contact pad 105f circumferentially aligned with the outermost point. Support element 104h shown in Figure 7H has a base attached to the outermost point of crown 102, a shaft with a simple 90° bend, and a circular contact pad 105h axially offset from the outermost point. Support elements 104i shown in Figure 7I have their base ends attached along the length of the strut 100 and circular contact pads 105i attached to their free ends. The shaft has a bend of approximately 120 degrees.

[0236] The support element 104j shown in FIG. 7J is similar to that shown in FIGS. 2A-2C, having a circular contact pad 105j at the free end of a linear shaft, but including a short cleft 106j formed in the crown 102j to allow for increased radial expansion.

[0237] In other embodiments, the support elements may have bends, bifurcations, multiple contact pads, and structural features to enhance their ability to support the expandable membrane in the area between adjacent posts and / or adjacent support rings. As shown in FIG. 7K, support element 104k is bifurcated in a Y-shape and has a pair of contact pads 105k. Support element 104l shown in FIG. 7L also has a bifurcation, with a pair of contact pads 105l and a third contact pad 106l located at the point of the bifurcation.

[0238] In yet other embodiments, the support elements may be formed as linked linear segments, optionally with contact pads at some or all of the junctions between the segments. For example, as shown in Figures 7M and 7N, support elements 104m and 104n each comprise a pair of linear segments with contact pads 105m and 105n, respectively, at the terminal free ends and inner contact pads 106m and 106n, respectively, at the junctions between the segments. The linear segments in support element 104m are attached at an angle of approximately 120°, while the linear segments in support element 104n are attached at a right angle (90°).

[0239] 7O-7R, various T-shaped support elements are illustrated having base ends attached to the inner surface of a U-shaped crown. The T-ends may extend into the gaps between adjacent rings, or may be flush with either of the rings, as shown in FIGS. 7O and 7P. Alternatively, the T-ends may be flush with the ring to which they are attached (FIG. 7Q), or may extend into the intermediate gap without contacting any of the rings (FIG. 7R). In some embodiments, the support elements in each ring extend in the same direction, as shown in FIG. 7O. Alternatively, the support elements in each ring may extend in opposing directions, as shown in FIG. 7P.

[0240] 7S, the support elements having base ends attached to the inner surface of the U-shaped crown may have unattached ends having different termination geometries that extend into the gaps between adjacent rings. For example, some of the terminations may include dampening or stop elements configured to engage adjacent rings and maintain a desired gap area therebetween.

[0241] 7T, the support elements, having base ends attached to the inside surface of the box- or U-shaped crown, may have recessed, unattached ends that essentially fill all of the space between adjacent struts on each ring (or that fill or cover substantially all of the space between adjacent struts on each ring in the as-patterned or as-delivered configuration). This is the preferred ring geometry, as shown in more detail in FIGS. 11A-11D, discussed in more detail below.

[0242] 7U-7Y and 7P, various support elements are illustrated having base ends that are attached to the outer surface of a U-shaped crown. The unattached ends (free ends) of the support elements may be T-shaped, L-shaped, angled, or have various other geometric shapes and will extend completely or partially into the gap elements between adjacent rings. The terminal ends may be flush with the adjacent rings, as shown in Figures 7O, 7U, 7W, 7X, and 7Y, or may not contact the adjacent rings, leaving an intermediate gap (Figure 7V).

[0243] 7Z-7AD, various support elements may be attached to one side of a crown and extend circumferentially toward an adjacent crown. A single lateral support element is shown in Figures 7Z, 7AB, and 7AC, while a pair of sliding lateral elements are shown in Figures 7AA and 7AD. The lateral elements may optionally extend across the outer surface of the adjacent crown, as shown in Figure 7AC.

[0244] As shown in Figures 7AE-7AP, the support elements may be formed as "lock and key" structures with straight or male elements slidably received within slotted or "clevis" members. Such support elements can accommodate circumferential and / or axial movement of adjacent ring elements as the scaffold is radially expanded. Such expandable or adaptable support elements may extend across an opening of a U-shaped cell (comprising a pair of struts joined by a crown), as shown in Figures 7AD and 7AE, or may extend from one ring to an adjacent ring, as shown in Figures 7AF-7AP. The base ends of the male and / or clevis elements may be attached to the inner or outer surface of the crown, the inner surface of the strut, may extend circumferentially, or may be inclined at an angle to the circumference. One or both of the male elements and the notch or clevis elements may have one or more bends. Although various geometries and combinations are shown in Figures 7AE-7AP, it should be understood that many other specific geometries may be utilized.

[0245] In some cases, the support elements may be formed between a pair of adjacent circumferential elements to form a single radially expandable ring, as shown in Figure 7AQ. Such a "double" ring structure may be formed helically, as separate parallel rings, or in any of the other configurations as shown herein.

[0246] 7AR, 7AR-1, and 7AR-2, a particular serpentine ring arrangement includes U-shaped cells with U-shaped support elements extending across the openings between adjacent crowns that are configured to expand from a crimped configuration, as shown in FIG. 7AR-1, to an expanded configuration, as shown in FIG. 7AR-2, as the ring is radially expanded.

[0247] FIG. 8 is an "unfolded" view of a further embodiment of a support scaffold 110 having adjacently connected radially expandable circumferential support rings 112 of different widths and differently configured support elements 114 constructed in accordance with the principles of the present invention. As with the previous embodiment, the support rings 112 are constructed with pairs of struts 115 joined by a crown 116. Support element 114a is a linear beam similar to support element 52 described with reference to FIGS. 2A-2D. Support element 114b has a single bend and is similar to support element 104m shown in FIG. 7M, but lacks a central contact pad between adjacent linear sections and is attached to struts 115 rather than crown 116. Support element 114c is a short straight beam with a distal contact pad. Support element 114d has a single bend and is similar to support element 104h in FIG. 7H. The scaffolding rings can have different numbers of crowns on adjacent rings, different cell periodicities on adjacent rings, support elements having different shapes, numbers, and frequencies on adjacent rings, different spacing between rings, and / or different ring amplitudes, as shown.

[0248] 9A and 9B, the support scaffold 120 comprises a plurality of radially expandable circumferential support rings 122 comprising struts 124 and crowns 126. Unlike the previous embodiment, there are no support elements attached to the support rings 122. Instead, the support rings 122 have a pattern that inherently provides enhanced support to the attached expandable membrane when used in an expandable distal tip of an aspiration catheter. More specifically, the support ring comprises serpentine or zigzag rings having a width W in the range of 0.1 mm to 1 mm, preferably 0.3 mm to 0.4 mm, a gap G between adjacent rings in the range of 0 mm to 1 mm, preferably 0.05 mm to 0.4 mm, crowns CS arranged along axial lines separated by intervals in the range of 0.1 mm to 1 mm, preferably 0.25 mm to 0.4 mm, and struts that diverge from the crowns at an angle α in the range of 0° to 90°, preferably 20° to 40° prior to expansion.

[0249] 9C illustrates a further alternative embodiment of the support scaffold 140 of the present invention having discrete support pads 150 located between the struts 144 of the serpentine radially expandable support ring 142. The struts 144 are joined by crowns 146 in a conventional manner, and adjacent support rings 142 are joined by links 147. The support pads 150 are attached to the membrane support member 152 in the V-shaped regions between adjacent struts 144, but are not otherwise attached to the remaining components of the expandable support structure 140. Preferably, but not necessarily, the support pads 150 may have a triangular shape that corresponds to the V-shaped regions in which they are attached. They may also have other shapes, such as circular, oval, or other rounded shapes.

[0250] 10A-10G, delivery of an aspiration catheter into a patient's vasculature will be described in accordance with the principles of the present invention. An aspiration catheter, for example, the aspiration catheter 12 shown in FIG. 1, is advanced to the area of ​​a blood clot C in a patient's blood vessel BV, typically a cerebral vessel, as shown in FIG. 10A. For convenience, only the expandable distal tip 18 of the aspiration catheter 12 is illustrated. As shown in FIGS. 10B and 10C, the balloon 26 of the distal dilatation catheter 14 is inflated, causing the catheter's expandable distal tip 18 to expand against the vessel wall. In some cases, the aspiration catheter 12 is first introduced over a guidewire into the blood vessel BV, and after the aspiration catheter is positioned, the distal tip dilatation catheter 14 is introduced. In other cases, the aspiration catheter 12 and the distal tip dilatation catheter 14 are introduced together or in tandem. After the distal tip 18 of the aspiration catheter 12 is expanded, the distal tip dilatation catheter 14 will be removed, as shown in FIG. 10D. After the clot has been aspirated, the aspiration catheter 12 is withdrawn through the sheath S (or guiding catheter), as shown in Figure 10E, causing the expanded distal tip 18 to be constricted (constricted) for removal, as shown in Figures 10F and 10G. Alternatively (not shown), the aspiration catheter is not withdrawn until the expandable tip proximal end reaches the distal end of the sheath, and then both the sheath and aspiration catheter are removed together as a unit.

[0251] 11A-11D, an alternative configuration of the expandable distal tip 18 of the aspiration catheter 12 will be described. The alternative expandable distal tip 218 of the aspiration catheter 12 includes both a support scaffold 238 and an expandable membrane 240. As described above, the expandable membrane 240 will typically comprise an elastic or inelastic (stretchable) polymeric membrane having the support scaffold 238 embedded or laminated therein. The support scaffold 238 will comprise a metal or metal alloy scaffold configured for balloon expansion, and will typically comprise a malleable metal, as described elsewhere herein.

[0252] The support scaffold 238 includes a plurality of radially expandable circumferential support rings 242. The rings 242 comprise a U-shaped or other shaped bent or cellular structure including struts 248 joined by crowns 250, with adjacent rings 242 connected end-to-end in a spiral pattern.

[0253] Each support element 252 has a base end 256 that is located between adjacent pairs of struts 248 and is attached to the inner radius of crown 250. The unattached end 258 (free end) of each support element 252 is recessed within the space between adjacent struts 248 but otherwise occupies most or all of the space between the adjacent struts prior to ring expansion.

[0254] Typically, but not necessarily, the support scaffold 238 will be laser cut from a metal alloy tube in an "unrolled" pattern, for example, as shown in Figures 11B and 11D. The pattern includes a coil support (reinforcement) region 244, which is intended to support at least the proximal portion of the tubular body 222, as best seen in Figure 11A. A short axial connection 246 may be provided at the transition between the support scaffold 238 and the coil support region 244 to provide stress relief between the highly flexible distal tip and the less flexible catheter shaft. The coil support region 244 may have a sufficient length to extend the entire length of the tubular body 222, but more typically will extend only over a shorter transition region at the distal end of the tubular body. The proximal portion of the tubular body 222 may have a braid or other form of reinforcement, as shown in Figure 1A.

[0255] As shown in Figures 11A-11D, the expandable distal tip 218 and the support scaffold 238 of the aspiration catheter 212 are in their unexpanded configuration, which is suitable for introduction through the patient's vasculature to the target clot location. However, once at the target clot location, the expandable distal tip 218 and the support structure 238 will be balloon expanded to engage the clot or the wall of the blood vessel adjacent to the clot, as described in more detail with reference to Figures 13A-13G herein below. As shown in Figure 11B, the proximal end of the expandable scaffold includes both an expandable section and a non-expandable section on the proximal end ring and is attached to the adjacent coil at at least one location (as shown). Alternatively, the terminal end may be attached to the adjacent expandable ring and / or adjacent non-expandable coil at one or more locations on the adjacent ring or turn by a link and / or attachment point. Alternatively, the proximal end ring of the expandable scaffold may be configured to be substantially non-expandable, having sections that are expandable and sections that are not expandable on the same ring, or configured to be fully expandable and separately attached proximally to a non-expandable structure.

[0256] As best seen in FIG. 11D , the distal end of the support scaffold 238 includes a termination ring 260 having an enlarged end 262 (enlarged amplitude) and a tapered end 264. The enlarged end 262 is attached to the distal end 266 of the final helical turn of these scaffolds 238. The enlarged end 262 is also attached to the tapered end 264 of the termination ring 260. In this manner, a transition is made between the helical orientation of the ring 242 and the “square” distal face 268 of the support scaffold 238. This “square” configuration precludes exposure of the free distal end of the ring to the vessel lumen as the aspiration catheter is advanced through the vasculature.

[0257] 11E and 11F are alternative detailed views of the transition region between the expandable scaffold 238 and the fixed diameter coil support region 244 of an aspiration catheter of the present invention. In both cases, a transverse link 246 provides stress relief between the transition between the support scaffold 238 and the coil support region 244. In FIG. 11F, the connection 247 between the support scaffold 238 and the coil support region 244 is thinned to create an inflection point and enhance bending.

[0258] 11G illustrates a preferred embodiment of the invention in which most or all of the support structures 252 remain recessed within the axial width of the ring prior to ring expansion and will emerge further into the gap after radial expansion of the distal tip. The axial width is defined by the distance between crowns 250 (as shown by lines 263), with the distal tip 258 of each tab-like support structure remaining between adjacent struts 248 until distal tip expansion.

[0259] Although support elements 252 preferably remain recessed, as shown in Figure 11G, distal tips 259 of cantilevered support elements of the present invention may also protrude into the gap area outside of line 263, as shown in Figure 11H, although such structures will generally not be as flexible as otherwise similar recessed structures.

[0260] As previously illustrated herein, exemplary helical support structures typically consist of a single helically wound serpentine, zigzag, or other ribbon with bends that allow for elongation in response to radial expansion of the associated ring. In other cases, as illustrated in Figures 11I and 11J, support structures 700 and 702 may have two, three, four, or more helically nested helical rings. As specifically illustrated in Figure 11I, support structure 700 includes first and second helically nested rings 710 and 712, respectively. As specifically illustrated in Figure 11J, support structure 702 includes first, second, and third helically nested rings 720, 722, and 724, respectively.

[0261] 12A-12D illustrate the support scaffold of the expandable distal tip of the aspiration catheter of FIGS. 11A-11C shown in an alternative expanded (deployed) configuration. The expanded distal tip scaffold can have a bell shape 238a (FIG. 12A), a conical shape 238b (FIG. 12B), a pear shape 238c (FIG. 12C), a rounded or arcuate conical shape 238d (FIG. 12D), and many other variations and combinations of shapes that taper radially outward in the distal direction.

[0262] FIG. 12E illustrates a support scaffold similar to that shown in FIG. 12A shown in an unexpanded configuration, with a reduced diameter tip 238e connected to a larger diameter distal shaft end 244e to facilitate introduction over a guidewire.

[0263] 13A-13G illustrate the steps of advancing and deploying the expandable distal tip 218 of the aspiration catheter of FIGS. 11A-11D within the vasculature of a patient in accordance with the principles of the present invention. The distal tip 218 is advanced to the region of a blood clot C in the patient's blood vessel BV, typically a cerebral vessel, as shown in FIG. 13A. For convenience, only the support scaffold 238 of the aspiration catheter's distal tip 218 is illustrated (without the expandable membrane 240). As shown in FIGS. 13B and 13C, the balloon 226 of the distal dilation catheter 214 is inflated, expanding the catheter's expandable distal tip 218 against the vessel wall. The aspiration catheter is typically first introduced over a guidewire into the blood vessel BV, and after the aspiration catheter is positioned, the distal tip dilation catheter 214 is introduced. In other cases, the aspiration catheter and the distal tip dilation catheter 214 may be introduced together or in tandem. After the aspiration catheter distal tip 218 has been expanded, the distal tip expansion catheter 214 will be removed, as shown in Figure 13D. After the clot has been aspirated, the aspiration catheter is removed through the sheath S, as shown in Figure 13E, narrowing the expanded distal tip 218 for removal, as shown in Figures 13F and 13G.

[0264] 14A and 14B illustrate how the "pitch angle" of a helical scaffold may be measured. FIG. 14A illustrates the "unfolded" pattern of an exemplary helical scaffold 300 in its crimped or pre-expanded configuration, while FIG. 14B illustrates the "unfolded" pattern of the same helical scaffold 300' in its radially expanded configuration. The pitch angle of the pre-expanded scaffold 300 is measured between a line L1 along the longitudinal axis of the scaffold and a line L2 drawn parallel to the rings 302 within the scaffold. The pitch angle α1 of the scaffold 300 in the pre-expanded or as-delivered configuration is typically 70°-89.9°, or more typically 80°-89.9, preferably 84°-89.9°, more preferably 85°-89°, and most preferably 86°-88°. The pitch angle α2 will exceed the pitch angle α1 for any given scaffold because as the scaffold expands radially, the pitch angle increases and approaches 90° as the scaffold is fully expanded.

[0265] 14C-14E ​​illustrate distal tip support scaffolds with varying pitch angles. Support scaffold 306, shown in its pre-expanded configuration, has a pitch angle of 87°. Support scaffold 308, shown in its pre-expanded configuration, has a pitch angle of 86°. Support scaffold 309, shown in its pre-expanded configuration, has a pitch angle of 85°.

[0266] 15A-15C are detailed views illustrating different bending patterns that may be utilized within the radially expandable distal tip ring of the present invention. A support ring 320 having a serpentine bending pattern is shown in FIG. 15A. A support ring 322 having a zigzag bending pattern is shown in FIG. 15B. A support ring 324 having a box-shaped (square-shaped) bending pattern is shown in FIG. 15C.

[0267] 15D and 15E are side and perspective views of a scaffold 330 having spirally arranged radially expandable rings 332 with a repeating omega shaped cell pattern.

[0268] 16 illustrates how the faceted outer surface of the radially expandable distal tip region of an aspiration catheter of the present invention approaches a circular circumference (achieving enhanced "roundness"). Cross-sectional views of an exemplary radially expandable distal tip region 340 are shown in a pre-expanded configuration (340) and a radially expanded configuration (340'). A circumferentially expanding ring 342 is embedded within a polymeric film 344 such that the outer surface of the radially expandable distal tip region forms several relatively flat facets 346 between the struts 348 of the scaffold 342.

[0269] In its pre-expanded configuration 340, the radially expandable distal tip region has a first radius r2 from the axial centerline C of the ring to the circumferential center of each facet 346 and a second radius R2 from the axial centerline C of the ring to the circumferential edge of each facet 346, the length of the first radius r2 being 80% to 99.9%, preferably 95% to 99.5%, more preferably 97.5% to 98.5%, and most preferably 98.5% to 99.5%, of the length of the second radius R2.

[0270] In its expanded configuration 340' (e.g., 50% or less, typically 100% or less, and sometimes 200% or less radial expansion), the radially expandable distal tip region has a first radius R1 from the ring's axial centerline C to the circumferential center of each strut 348 and a second radius r1 from the ring's axial centerline C to the circumferential edge of each facet 346, the length of the first radius being 75%-99%, preferably 97%-99%, often 98%-99%, and more typically 98.5% of the length of the second radius. A circularity in the expanded configuration of greater than 97% is preferred, greater than 98% is more preferred, and greater than 98.5% is most preferred.

[0271] FIG. 17 identifies various properties that may be used to configure the structure of a helical radially expandable distal tip ring of the present invention, along with the values ​​as shown in Table 1 below. [Table 1]

[0272] 18A-18C are side, perspective, and "unfolded" views of an expandable scaffold 360 comprising multiple laterally oriented, axially connected, expandable rings 362 joined by axial connections 364.

[0273] FIG. 19 identifies various properties that can be used to construct an expandable scaffold structure comprising multiple laterally oriented, axially connected, expandable rings, such as those shown in FIGS. 18A-18C, along with values ​​as shown in Table 2 below. [Table 2]

[0274] 20A and 20B show side and "unfolded" views of an expandable scaffold 380 comprising multiple parallel axially connected, expandable rings 382 joined by axial connections 384 inclined relative to the longitudinal axis of the scaffold at an acute pitch angle α3.

[0275] FIG. 21 is a “unfolded” view of an expandable scaffold 390 having sections 392 and 394 with in-phase and out-of-phase aligned cells, respectively.

[0276] FIG. 22 is a “unfolded” view of an expandable scaffold 400 comprising multiple rings 402 with gaps 404 between them having varying lengths.

[0277] 23A is an "unfolded" view of an expandable scaffold 500 comprising multiple rings 502 with gaps 504 between them arranged in a spiral pattern. The rings 502 are "smooth" or linear, without bends or curves, in the unfolded pattern. As shown in detail in FIG. 23B, the rings 502 will each be in a serpentine pattern. Although a simple serpentine pattern with struts 506 joined by crowns 508 is illustrated in FIG. 23B, the rings 502 may comprise any cell pattern described herein or otherwise known in the art.

[0278] Figures 23C-23E are rotated side views of the expandable scaffold 500 of Figure 23A. The view of scaffold 500 as shown in Figure 23D is rotated 90° in a first rotational orientation relative to the view in Figure 23C, while the view shown in Figure 23E is rotated 90° in the opposite rotational orientation. Because the rings 502 of scaffold 500 are "smooth," i.e., have no bends, the side view does not change as the scaffold is rotated about its longitudinal axis.

[0279] FIG. 24A is an "unfolded" view of an expandable scaffold 520 comprising multiple rings 522 with gaps 524 between them arranged in a spiral pattern, with each ring having a first curved shape in the unfolded pattern. Each ring 522 is non-linear and includes two curved or bent regions 532, one of which spans the ends that are joined, e.g., 534a and 534b, as the scaffold is rolled. As shown in detail in FIG. 24B, each of the rings 522 will be in a serpentine pattern. Although a simple serpentine pattern with struts 526 joined by crowns 528 is illustrated in FIG. 24B, the rings 522 may comprise any cell pattern described herein or otherwise known in the art.

[0280] 24C-24E are rotated side views of the expandable scaffold 520 of FIG. 24A. The view of scaffold 520 as shown in FIG. 24D is rotated 90° in a first rotational orientation relative to the view in FIG. 24C, while the view shown in FIG. 24E is rotated 90° in the opposite rotational orientation. Curves 532 in the rings 522 of scaffold 520 shift the observed tilt of each ring 522 from a rightward tilt as shown in FIG. 24D to a leftward tilt as shown in FIG. 24E.

[0281] FIG. 25A is an "unfolded" view of an expandable scaffold 540 comprising multiple rings 542 with gaps 544 between them arranged in a spiral pattern, with each ring having a second curved shape in the unfolded pattern. Each ring 542 is non-linear and includes three curved or bent regions 552 (one of which spans the ends 554a and 554b that are joined when the scaffold is rolled). As shown in the detailed view, FIG. 25B, each of the rings 542 will be in a serpentine pattern. Although a simple serpentine pattern with struts 546 joined by crowns 548 is illustrated in FIG. 25B, the rings 542 may comprise any cell pattern described herein or otherwise known in the art.

[0282] Figures 25C-25E are rotated side views of the expandable scaffold 540 of Figure 25A. The view of scaffold 540 as shown in Figure 25D is rotated 90° in a first rotational orientation relative to the view in Figure 25C, while the view shown in Figure 25E is rotated 90° in the opposite rotational orientation. The curves 552 within the rings 542 of scaffold 540 shift the observed tilt of each ring 542 back and forth as the scaffold is rotated about its longitudinal axis, as can be seen by comparing the images in Figures 25C, 25D, and 25E.

[0283] FIG. 26 is an “unfolded” view of the ring pattern, comprising rings 580 having S-shaped expandable elements 582 joined by non-extensible circumferential links 584, shown prior to expansion.

[0284] FIG. 27 is an “unrolled” view of the ring pattern with rings 590 formed from wire bent into a serpentine pattern with integrated cantilevered support elements 592 formed by tight U-shaped turns that are glued, soldered, welded or otherwise joined together to prevent separation.

[0285] Figures 28A and 28B are "unfolded" views of a ring pattern with closed cell box rings 600 shown in their unexpanded and expanded configurations, respectively. The boxes 602 within each ring stretch circumferentially from a rectangular unexpanded shape as shown in Figure 28A to a generally hexagonal elongated shape as shown in Figure 28B. Such stretching allows each ring to radially expand in response to an opening force provided by a balloon or other deployment tool.

[0286] Figures 29A and 29B are "unfolded" views of a ring 610 with closed cell boxes 612 shown in its unexpanded and expanded configurations, respectively. The rings 610 are similar to the rings 600 illustrated in Figures 28A and 28B (Figure 29A), except that they further comprise cantilevered support elements 614 that, in the unexpanded configuration, are recessed between the attached circumferential links 616 and the circumferentially adjacent box elements 612. The cantilevered support elements 614 remain within the spaces between adjacent expanded boxes and provide additional support for the surrounding membrane after the ring is radially expanded, as shown in Figure 29B (not shown).

[0287] Figures 30A and 30B are "unfolded" views of a ring 620 with an alternative closed cell box formed from side members 622 and cross members 624. The side members are initially formed into a U-shape when the ring is in an unexpanded configuration, as shown in Figure 30A. The U-shape elongates as the ring is radially expanded, as shown in Figure 30B.

[0288] 31A-31C illustrate an exemplary method for embedding a radially expandable support scaffold 630 within a polymer membrane 640 (one or more membranes formed from the same or different materials). The support scaffold 630 has a serpentine pattern with struts 632 having gaps 634 between them, as shown in FIG. 31A. The support scaffold 630 may be embedded within the polymer membrane 640 by first placing sheets 636 and 638 of a desired polymer or polymers across the exterior and interior surfaces of the ring 630, as shown in FIG. 31B. By applying heat and pressure to the polymer sheets, the polymer will flow into the gaps 634 and form a continuous polymer membrane matrix 640 having exterior and interior surfaces 642 and 644, respectively, as shown in FIG. 31C.

[0289] The distal tip, comprising scaffold 630 and polymer membrane matrix 640, is shown in its radially expanded configuration in Figure 32. The polymer matrix 640 is elastic, allowing the distal tip to stretch and thin as it is expanded. The polymer membrane would normally impart a radial closure force, but the expanded supporting scaffold 630 would have sufficient hoop strength (crush resistance) to hold the distal tip open against both the elastic force of the polymer membrane and the applied vacuum during clot aspiration.

[0290] Although certain aspects or examples of the present disclosure have been described in detail, variations and modifications and combinations of all or part of these aspects and examples will be apparent to those skilled in the art, including aspects, embodiments, or examples that are within the scope of the present invention and may not provide all the features and benefits described herein. It will be understood by those skilled in the art that the present disclosure extends beyond the specifically disclosed aspects, embodiments, or examples to other alternative or additional examples or embodiments and / or uses and their obvious modifications and equivalents. In addition, while some variations have been shown and described in various details, other modifications that fall within the scope of the present disclosure will be readily apparent to those skilled in the art based on the present disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the aspects, embodiments, and / or examples may be made and still fall within the scope of the present disclosure. It should therefore be understood that various features and aspects of the disclosed embodiments may be combined with or substituted for one another to form various aspects or examples of the present disclosure. It is therefore intended that the scope of the present disclosure disclosed herein should not be limited by the disclosed embodiments or examples described above. With respect to all of the embodiments and examples described above, any method steps need not be performed, for example, sequentially.

Claims

1. A catheter comprising: a tubular catheter body having a proximal end, a distal end and a lumen extending therebetween; a radially expandable distal tip at a distal end of the tubular catheter body, the expandable distal tip having a central passageway continuous with a lumen of the tubular catheter body, the expandable distal tip comprising a support structure coupled to a membrane, the support structure comprising: (a) a plurality of radially expandable circumferential rings arranged along a longitudinal axis with circumferential gaps therebetween; (b) a number of support elements, each support element having a proximal end and a free end, the proximal end attached to one of the radially expandable rings and the free end extending axially and / or circumferentially away from the one of the radially expandable rings; a radially expandable distal tip comprising: A catheter comprising:

2. The catheter of claim 1 , wherein at least some of the free ends of the support elements are recessed within the circumferential ring and do not protrude into the circumferential gap prior to radial expansion of the distal tip.

3. The catheter of claim 2 , wherein at least some of the free ends of the support elements protrude into the circumferential gap after expansion of the distal tip.

4. The catheter of claims 1-3, wherein at least some of the radially expandable circumferential rings comprise a serpentine or zigzag structure including struts joined by crowns, the base ends of the support elements being attached inside the crowns and the free ends being positioned between adjacent struts attached to the crowns.

5. The catheter of claims 1-4, wherein the radially expandable rings are cylindrically arranged within a cylindrical shell prior to expansion.

6. The catheter of claim 2 , wherein the support element is configured to fit within a cylindrical contour defined by the support structure prior to expansion.

7. The catheter of claims 1-6, wherein the distal tip has a diameter equal to or less than that of the tubular catheter body prior to expansion.

8. The catheter of claims 1-6, wherein the distal tip has a diameter greater than that of the tubular catheter body prior to expansion.

9. The catheter of claims 1-5, wherein the expandable support structure is configured to expand into a cylindrical shape, a cone shape, or a combination thereof after expansion.

10. The catheter of claims 1-9, wherein the expandable support structure is configured to expand in response to expansion of a balloon catheter within the expandable structure.

11. The catheter of claims 1-9, wherein the expandable support structure is configured to self-expand when released from a radial constraint.

12. The catheter of claims 1-11, wherein at least some of the support elements extend axially and / or circumferentially from the radially expandable ring into the circumferential gap.

13. The catheter of claims 1-12, wherein at least some of the support elements extend axially and / or circumferentially from the radially expandable ring into adjacent gaps between two struts.

14. The catheter of claim 13 , wherein at least some of the rings include expandable cells that extend circumferentially and accommodate radial expansion.

15. The catheter of claim 14 , wherein at least some of the expandable cells are open cells.

16. The catheter of claim 15, wherein the open cells are selected from the group consisting of U-shaped sections, V-shaped sections, and ω-shaped elements.

17. The catheter of claims 14-16, wherein at least some of the expandable cells are closed cells.

18. The catheter of claim 17 , wherein the closed cell is a box section.

19. The catheter of claims 14-18, wherein at least some of the support elements are positioned inside the expandable cells prior to expansion of the circumferential ring.

20. The catheter of claims 14-18, wherein at least some of the support elements are positioned outside the expandable cells prior to expansion of the circumferential ring.

21. The catheter of claims 1-20, wherein at least some of the support elements on at least some adjacent expandable rings extend axially and / or circumferentially, and wherein each of the at least some support elements is contained within one cell space on the ring.

22. The catheter of claims 1-20, wherein at least some of the support elements are on at least some adjacent expandable rings, and each support element is contained within a cell space, filling a majority or substantially all of the space within the cell space on at least some of the rings in a patterned or delivered scaffold configuration.

23. The catheter of claims 1-20, wherein at least some adjacent rings have a plurality of support elements on each ring, each of the support elements being contained within a cell space on at least some of the adjacent rings in a patterned or delivered scaffold configuration.

24. The catheter of claims 1-20, wherein there are at least some adjacent expandable rings, each ring comprising a plurality of expandable cells, most or all of the cells containing at least one support element.

25. 21. The catheter of claims 1-20, wherein there are at least some adjacent expandable rings, each ring comprising a plurality of expandable cells, at least half, a majority, or all of the cells containing at least one support element, the support elements having a symmetrical pattern on the at least some rings or along a scaffold length.

26. The catheter of claims 1-20, wherein there are at least some adjacent rings, each ring comprising a plurality of expandable cells, at least half, a majority or all of the cells containing at least one support element, and the support element segments connecting the base to the free ends have an average width or width that is equal to or greater than the average width or width of adjacent struts or adjacent crowns on the rings.

27. The catheter of claims 1-20, wherein there are at least some adjacent expandable rings, each ring comprising a plurality of expandable cells, at least half, a majority, or all of the cells containing at least one support element, the support elements having substantially the same shape, size, and / or configuration on at least some of the rings or along a scaffold length.

28. The catheter of claims 1-27, wherein at least some of the support elements comprise linear sections.

29. The catheter of claims 1-27, wherein at least some of the support elements comprise non-linear sections.

30. The catheter of claims 1-29, wherein at least some of the support elements include enlarged tips at the free ends.

31. The catheter of claims 1-30, wherein at least some of the support elements are bifurcated into two or more sections in a direction toward the free end.

32. The catheter of claims 1-31, wherein at least some of the radially expandable rings comprise a serpentine, zigzag, square, or omega pattern including struts joined by crowns.

33. The catheter of claims 1-32, wherein at least some of the adjacent rings are joined by axial connections and / or attachment points on the adjacent rings.

34. The catheter of claims 1-32, wherein at least some of the adjacent expandable rings are continuously joined end-to-end in a helical pattern.

35. 35. The catheter of claim 34, wherein at least some of the adjacent rings in the helical arrangement comprise nonlinearity.

36. 36. The catheter of claim 35, wherein all of the adjacent rings in the helical arrangement are free of nonlinearity.

37. 36. The catheter of claim 35, wherein at least some adjacent rings in the helical pattern are joined by one or more links or attachment points.

38. The catheter of claims 1-32, wherein at least some adjacent expandable rings have no axial connections or attachment points therebetween.

39. The catheter of any one of claims 1-38, wherein the membrane comprises an elastic membrane.

40. 40. The catheter of claim 39, wherein the membrane covers at least an outer surface of the expandable support structure.

41. The catheter of claims 39-40, wherein the membrane covers at least an inner surface of the expandable support structure.

42. The catheter of claims 39-41, wherein the membrane comprises one or more elastomers.

43. The one or more elastomers may be selected from the group consisting of NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft ＴＭ 596-50A, NeuSoft NEU 455-55A, NeuSoft NEU 455-60A NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG 80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A Tecoflex TT-18095A, Elastollan S 50 A 15SPF Elastollan S 60 A 10W Elastollan S 60 A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane Rx50A, Texin RXT 70A, Chronoflex C 80A-Q, Chronoflex AL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 43. The catheter of claim 42, wherein the polymer is selected from the group consisting of ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex 00-30, Ecoflex 00-20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, Clonoprene, Chronocene, Clonosyl, combinations thereof, or equivalents.

44. A catheter according to any one of claims 39-43, wherein the support structure is embedded within the elastomer by the application of heat and / or pressure.

45. A catheter according to any one of claims 39 to 44, wherein the elastic membrane has isotropic properties.

46. A catheter according to any one of claims 39 to 44, wherein the elastic membrane has anisotropic properties, the membrane being more elastic in the circumferential direction than in the axial direction.

47. The catheter of any one of claims 1-38, wherein the membrane comprises an inelastic membrane.

48. The one or more expandable membranes may be one or more polymers, such as polyethylene, such as LDPE, HDPE, Ultra HMWPE, or equivalents; Pebax, such as Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, or equivalents; Nylon, such as Nylon 12, Nylon 6 / 6, or Nylon 6; Polyurethane, such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64 ... 72D, a fluoropolymer, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropene), poly(vinylidene fluoride-co-hexafluoropropene), fluorinated ethylene propylene, polychlorotrifluoroethylene ethylene, or equivalents, or other polymers.

49. The catheter of claims 1-48, wherein the expandable membrane is formed on the expandable scaffold by heat shrinking.

50. The catheter of claims 1-48, wherein the expandable membrane is formed by laminating the expandable scaffold between two layers of the elastomer.

51. 51. The catheter of claim 50, wherein the two layers are bonded to one another such that a seal exists between the layers.

52. The catheter of claims 1-51, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter scaffolding comprising a helical coil.

53. 53. The catheter of claim 52, wherein the helical coil is formed contiguous with the expandable structure.

54. 54. The catheter of claim 53, wherein the helical coil comprises a plurality of turns joined end-to-end in a helical pattern.

55. A catheter as described in claims 52-54, wherein the distal turn of the helical coil is connected to the proximal turn of the helical expandable support structure by one or more links and / or attachment points.

56. A catheter as described in claims 52-55, wherein a distal end of a distal helical turn of the helical coil is attached to a proximally adjacent helical turn of the helical expandable structure.

57. The catheter of claims 52-56, wherein at least a portion of the helical coil is continuous with the expandable scaffold.

58. A catheter according to any one of claims 4-57, wherein at least some of the multiple support elements have their proximal ends attached to a strut.

59. A catheter according to any one of claims 4 to 57, wherein at least some of the multiple support elements have their proximal ends attached to the crown.

60. 1. A method for aspirating a blood clot from a patient's vascular system, the method comprising: Positioning a distal tip of an expandable support structure of a catheter according to any one of claims 1 to 60 in the patient's vasculature at the region of the clot; expanding the distal tip to engage the clot; applying negative pressure to a proximal end of a lumen within the catheter body to aspirate the clot into a central passage of the expanded distal tip; A method comprising:

61. A catheter comprising: a tubular catheter body having a proximal end, a distal end and a lumen extending therebetween; an expandable support structure at a distal end of the tubular catheter body and having a central passageway continuous with a lumen of the tubular catheter body, the expandable support structure including an expandable membrane and a supporting scaffold configured to radially expand the expandable membrane, the scaffold comprising: (a) a plurality of radially expandable rings arranged along a longitudinal axis, at least some of the radially expandable rings extending circumferentially and including expandable cells adapted for radial expansion; (b) a number of support elements attached at least at one location on or adjacent to at least some of the expandable cells on the radially expandable ring, at least some of the support elements extending into, from, or between the expandable cells and supporting the membrane when the membrane is expanded from a delivery configuration to an expanded configuration; an expandable support structure comprising: A catheter comprising:

62. 62. The catheter of claim 61, wherein the expandable cells comprise struts joined by crowns to form a V-shaped, U-shaped, omega-shaped, or box-shaped expandable element.

63. 63. The catheter of claim 61 or 62, wherein at least some of the adjacent rings are joined by axial connections.

64. 62. The catheter of claim 61, wherein at least some of the adjacent rings are continuously joined end-to-end in a helical pattern.

65. 65. The catheter of claim 64, wherein at least some of the adjacent rings in the helical pattern comprise non-linearity.

66. 65. The catheter of claim 64, wherein all of the adjacent rings in the helical arrangement are free of nonlinearity.

67. 67. The catheter of claims 61-66, wherein the radially expandable rings are cylindrically arranged within a cylindrical shell prior to expansion.

68. 67. The catheter of claim 66, wherein the cylindrical shell has a diameter equal to or less than that of the tubular catheter body prior to expansion.

69. 69. The catheter of claim 67 or 68, wherein the support element fits within the cylindrical shell.

70. The catheter of claims 61-66, wherein the expandable support structure is configured to expand into a cylindrical shape, a cone shape, or a combination thereof after expansion.

71. The catheter of claims 61-70, wherein the expandable support structure is configured to expand in response to expansion of a balloon catheter within the expandable structure.

72. The catheter of claims 61-70, wherein the expandable support structure is configured to self-expand upon release from a radial constraint.

73. The catheter of claims 61-72, wherein at least some of the support elements extend circumferentially from the radially expandable ring into the cell spaces.

74. The catheter of claims 61-73, wherein at least some of the support elements extend axially from the radially expandable ring into and / or beyond the cell spaces.

75. The catheter of claims 61-74, wherein at least some of the support elements comprise linear sections.

76. The catheter of claims 61-75, wherein at least some of the support elements comprise non-linear sections.

77. A catheter according to any one of claims 61-76, wherein at least some of the support elements include enlarged tips at their free ends.

78. A catheter as described in claims 61-77, wherein at least some of the support elements are bifurcated into two or more sections in a direction towards the free end.

79. A catheter as described in claims 61-78, wherein at least some of the support elements have two or more sections attached to the struts or crowns and joined together within the cell spaces.

80. The catheter of any one of claims 61-79, wherein the expandable membrane comprises an elastic membrane.

81. 81. The catheter of claim 80, wherein the elastic membrane comprises one or more elastomers.

82. The one or more elastomers may be selected from the group consisting of NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft ＴＭ 596-50A, NeuSoft NEU 455-55A, NeuSoft NEU 455-60A NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG 80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A Tecoflex TT-18095A, Elastollan S 50 A 15SPF Elastollan S 60 A 10W Elastollan S 60 A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane Rx50A, Texin RXT 70A, Chronoflex C 80A-Q, Chronoflex AL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 82. The catheter of claim 81, wherein the catheter is selected from the group consisting of ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex 00-30, Ecoflex 00-20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, Clonoprene, Chronocene, Clonosyl, combinations thereof, or the like.

83. A catheter as described in claims 80-82, wherein the elastic membrane has isotropic properties.

84. A catheter as described in claims 80-82, wherein the elastic membrane has anisotropic properties, the membrane being more elastic in the circumferential direction than in the axial direction.

85. 80. The catheter of claims 61-79, wherein the expandable membrane comprises a non-elastic but stretchable membrane.

86. The non-elastic membrane may be made of one or more polymers such as polyethylene, e.g., LDPE, HDPE, Ultra HMWPE, or equivalent; Pebax, e.g., Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, or equivalent; Nylon, e.g., Nylon 12, Nylon 6 / 6, or Nylon 6; Polyurethane, e.g., Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64 ... 72D, a fluoropolymer, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropene), poly(vinylidene fluoride-co-hexafluoropropene), fluorinated ethylene propylene, polychlorotrifluoroethylene ethylene, or equivalents, or other polymers.

87. The catheter of claims 61-86, wherein the expandable membrane is formed on the expandable scaffold by heat shrinking.

88. A catheter according to any one of claims 61-86, wherein the expandable membrane is formed by lamination between two layers of the elastomer.

89. 90. The catheter of claim 88, wherein the two layers are bonded to one another such that a seal exists between the layers.

90. A catheter according to any one of claims 61-89, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter scaffolding.

91. 91. The catheter of claim 90, wherein the catheter scaffolding is continuous with the scaffolding within the expandable structure.

92. 92. The catheter of claim 91, wherein at least a portion of the catheter scaffolding is continuous with the expandable scaffold.

93. 1. A method for aspirating a blood clot from a patient's vascular system, the method comprising: Positioning a distal tip of an expandable support structure of a catheter of any one of claims 61-92 in the region of the clot within the patient's vasculature; expanding the distal tip to engage the clot adjacent a region of the clot; applying negative pressure to a proximal end of a lumen within the catheter body to aspirate the clot into a central passage of the expanded expandable structure; A method comprising:

94. 1. A suction catheter comprising: a tubular catheter body having a proximal end, a distal end and a lumen extending along a longitudinal axis; a distal tip having a proximal end attached to the distal end of the tubular catheter body and a central passageway longitudinally continuous with a lumen of the tubular catheter body, the distal tip adapted to expand from a radially contracted configuration to a radially expanded configuration in response to a radially outward expansive force applied within the distal tip; Equipped with the distal tip includes an expandable membrane and an expandable support member; the expandable support member comprises a plurality of rings spaced along the longitudinal axis with circumferential gaps therebetween, at least some of the rings comprising a malleable metal or metal alloy configured to plastically deform and circumferentially expand the scaffold in response to an outward radial expansion force applied within the distal tip. catheter.

95. 95. The catheter of claim 94, wherein the expandable membrane covers or is attached to an inner and / or outer surface of the expandable support member.

96. 95. The catheter of claim 94, wherein the expandable support member is embedded within the expandable membrane.

97. A catheter according to any one of claims 94-96, wherein the support member has a crimped delivery configuration (as a delivery configuration) and an expanded deployed configuration.

98. A catheter as described in any one of claims 94-97, wherein the radially contracted configuration has a maximum outer diameter in the range of 0.5 mm to 30 mm, and the radially expanded configuration has a maximum outer diameter in the range of 1.3 mm to 40 mm.

99. A catheter as described in any one of claims 94-98, wherein the distal tip is configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to an outward radial expansion force applied within at least a portion of the distal tip.

100. A catheter as described in any one of claims 94-99, wherein the distal tip is configured to expand from an initial cylindrical shape to an expanding conical configuration in response to an outward radial expansion force applied within at least a portion of the distal tip.

101. The catheter of any one of claims 94-100, wherein the tubular catheter body has a length from the proximal end to the distal end in the range of 50 cm to 200 cm, an outer diameter in the range of 0.5 mm to 30 mm, and an inner lumen diameter of 0.25 mm to 25 mm.

102. 102. A catheter according to any one of claims 94-101, wherein the distal tip has, in its initial radially contracted configuration, a bending resistance of less than 1 N, preferably less than 0.5 N, more preferably less than 0.3 N, even more preferably less than 0.2 N, and, in its radially expanded configuration, a collapse pressure of 0.5 atm or greater, preferably 0.75 atm or greater, more preferably 1 atm or greater.

103. The catheter of claim 102, wherein the bending resistance is measured by a three-point flexure test as described herein.

104. 104. The catheter of claim 102 or 103, wherein the collapse pressure is applied to the proximal end of the catheter body lumen with a central passageway of the distal tip occluded.

105. A catheter according to any one of claims 94-104, wherein the distal tip has a minimum bend radius, without kinking, of 5 mm, preferably 3 mm, more preferably 2 mm in its radially contracted configuration, and a minimum bend radius, without kinking, of 10 mm, preferably 6 mm, more preferably 2 mm in its radially expanded configuration.

106. A catheter as described in any one of claims 94-105, wherein the rings of the support member span a length, measured in the longitudinal direction, in the range of 0.2mm to 200mm, preferably in the range of 1mm to 40mm, more preferably in the range of 10mm to 40mm.

107. The catheter of any one of claims 94-106, wherein the support member consists of between 5 and 100 longitudinally arranged rings.

108. A catheter as described in any one of claims 94-107, wherein the gaps between adjacent rings have a length in the range of 0.02mm to 0.3mm, preferably 0.05mm to 0.2mm, more preferably 0.05mm to 0.15mm, measured in the longitudinal direction when the support member is in a delivery configuration.

109. 109. The catheter of claim 108, wherein the length of the gap between adjacent rings is constant.

110. 109. The catheter of claim 108, wherein the length of the gap between adjacent rings is variable.

111. A catheter as described in any one of claims 94-110, wherein at least some of the plurality of rings include a bend configured to straighten in response to an outward radial expansion force applied within the distal tip, the straightening of the bend resulting in an increase in the circumference of the ring.

112. 112. The catheter of claim 111, wherein at least some of the bends comprise a U-shaped bend, a V-shaped bend, an omega-shaped bend, and a box-shaped bend.

113. A catheter as described in claim 111 or 112, wherein at least some of the rings comprise at least 2 bends per mm of circumferential length, preferably at least 3 bends per mm of circumferential length, typically 2 to 12 bends per mm of circumferential length, more typically 4 to 10 bends per mm of circumferential length.

114. The catheter of any one of claims 94-113, wherein at least some of the adjacent rings are continuously joined end-to-end in a helical pattern.

115. 115. The catheter of claim 114, wherein at least some of the adjacent rings in the helical pattern comprise non-linearity.

116. 115. The catheter of claim 114, wherein all of the adjacent rings in the helical pattern are free of nonlinearity.

117. The catheter of any one of claims 94-116, wherein at least some of the adjacent rings are joined by an axial connection.

118. 118. The catheter of claim 117, wherein at least some of the adjacent rings are joined by a single axial link, by two axial links, or by three or more axial links.

119. 118. The catheter of claim 117, wherein at least some of the adjacent rings are not formed contiguous but are joined to adjacent rings only by one or more axial connections.

120. The malleable metal may be cobalt chrome, e.g., L-605, MP35N, Stellite 6B, ASTM F1537 / F799 Alloy 1, ASTM F1537 / F799 Alloy 2. The catheter of any one of claims 94-119, comprising a metal or metal alloy selected from the group consisting of stainless steel, e.g., 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L, and 420S, tantalum, niobium, tungsten, molybdenum, platinum, platinum alloys, e.g., platinum-iridium, platinum-chromium, platinum-cobalt-chromium, magnesium, magnesium alloys, e.g., Mg-3A1-1Z, Mg-Zn-Se, and Mg-Zn-Cu, zinc, or the like, or others.

121. The catheter of any one of claims 101-112, wherein the tubular membrane comprises an elastic membrane.

122. 122. The catheter of claim 121, wherein the elastic membrane comprises one or more elastomers.

123. The one or more elastomers may be selected from the group consisting of NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft ＴＭ 596-50A, NeuSoft NEU 455-55A, NeuSoft NEU 455-60A NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG 80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A Tecoflex TT-18095A, Elastollan S 50 A 15SPF Elastollan S 60 A 10W Elastollan S 60 A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane Rx50A, Texin RXT 70A, Chronoflex C 80A-Q, Chronoflex AL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 123. The catheter of claim 122, wherein the catheter is selected from the group consisting of ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex 00-30, Ecoflex 00-20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3533, Clonoprene, Chronocene, Clonosyl, combinations thereof, or the like.

124. A catheter as described in claims 121-123, wherein the elastic membrane has isotropic properties.

125. A catheter as described in claims 121-123, wherein the elastic membrane has anisotropic properties, the membrane having higher elasticity in the circumferential direction than in the axial direction.

126. The catheter of any one of claims 94-125, wherein the tubular membrane comprises an inelastic membrane.

127. The non-elastic membrane may be made of one or more polymers such as polyethylene, e.g., LDPE, HDPE, Ultra HMWPE, or equivalent; Pebax, e.g., Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, or equivalent; Nylon, e.g., Nylon 12, Nylon 6 / 6, or Nylon 6; Polyurethane, e.g., Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64 ... 72D, a fluoropolymer, e.g., PTFE, poly(vinylidene fluoride-co-hexafluoropropene), poly(vinylidene fluoride-co-hexafluoropropene), fluorinated ethylene propylene, polychlorotrifluoroethylene ethylene, or equivalents, or other polymers.

128. 128. The catheter of claim 126 or 127, wherein the inelastic membrane is configured to plastically deform as the support member expands.

129. A catheter as described in claims 126-127, wherein the membrane is configured to unfold as the support member expands.

130. A catheter as described in any one of claims 94-129, wherein the distal tip is formed by heat shrinking the tubular membrane onto the expandable support member.

131. A catheter as described in claims 94-129, wherein the distal tip is formed by laminating the expandable support member between layers of the tubular membrane.

132. 132. The catheter of claim 131, wherein the layers are bonded to one another such that a seal exists between the layers.

133. A catheter as described in any one of claims 94-132, wherein the membrane comprises at least two membrane compartments.

134. The catheter of claim 133, wherein the at least two membrane compartments comprise a single type of material.

135. 135. The catheter of claim 134, wherein the at least two membrane sections comprise at least two types of material.

136. The catheter of any one of claims 133-135, wherein the at least two membrane sections cover at least an outer surface of the expandable support member.

137. The catheter of any one of claims 133-136, wherein the at least two membrane sections cover at least the inner surface of the expandable support member.

138. The catheter of any one of claims 136-137, wherein the at least two membrane sections cover both the inner and outer surfaces of the expandable support member.

139. A catheter as described in any one of claims 94-138, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter supporting member.

140. 140. The catheter of claim 139, wherein the catheter support member is continuous with the expandable support member.

141. 141. The catheter of claim 140, wherein the catheter support member and the expandable support member are patterned from the same tube.

142. 141. The catheter of claim 140, wherein the catheter supporting member and the expandable support member are formed from one or more bent wires that span at least a portion of the catheter supporting member and the expandable support member, respectively.

143. A catheter as described in claims 94-142, further comprising a number of support elements, each support element having a base end and a free end, the base end attached to one of the radially expandable rings and the free end extending into an adjacent circumferential gap.

144. 144. The catheter of claim 143, wherein at least some of the plurality of rings comprise struts joined by bends.

145. 145. The catheter of claim 144, wherein at least some of the multiple support elements have their base ends attached to a post.

146. 145. The catheter of claim 144, wherein at least some of the multiple support elements have their proximal ends attached to a bend.

147. 145. The catheter of claim 144, wherein at least some of the multiple support elements have their base ends attached to an inner surface of the ring.

148. 144. The catheter of claim 143, wherein at least some of the multiple support elements have their base ends attached to an outer surface of the ring.

149. A catheter according to any one of claims 143-148, wherein at least some of the multiple support elements have a constant width across their distal portions.

150. A catheter according to any one of claims 143-148, wherein at least some of the multiple support elements have variable widths across their distal portions.

151. A catheter according to any one of claims 143-150, wherein at least some of the multiple support elements have distal tips that extend into the adjacent circumferential gaps.

152. A catheter according to any one of claims 143-150, wherein at least some of the multiple support elements have distal tips that terminate flush with the bends that join the struts.

153. A catheter according to any one of claims 143-150, wherein at least some of the multiple support elements have distal tips that are recessed between adjacent bends that join the struts.

154. 1. A suction catheter comprising: a tubular catheter body having a proximal end, a distal end and a lumen extending along a longitudinal axis; a distal tip having a proximal end attached to the distal end of the tubular catheter body and a central passageway longitudinally continuous with a lumen of the tubular catheter body, the distal tip adapted to expand from a radially contracted configuration to a radially expanded configuration in response to a radially outward expansive force applied within the distal tip; Equipped with the distal tip includes a tubular membrane and an expandable support member; the expandable support member comprises a plurality of rings spaced along the longitudinal axis with circumferential gaps therebetween, at least some of the rings comprising circumferentially adjacent cells having bends configured to unbend and allow the rings to expand in response to an outward radial expansion force applied within the distal tip; Suction catheter.

155. 155. The catheter of claim 154, wherein the cells are arranged in any one or more of a serpentine pattern, an omega wave pattern, a zigzag pattern, and a square wave pattern.

156. 156. A catheter as described in claim 154 or 155, wherein the cells comprise struts joined by bends.

157. A catheter as described in any one of claims 154-156, wherein the circumferentially adjacent cells have a cell period (the distance between like points on circumferentially adjacent cells) in the range of 0.05 mm to 0.5 mm, preferably 0.1 mm to 0.4 mm, and more preferably 0.15 mm to 0.35 mm when in the support member in a delivery configuration.

158. A catheter as described in any one of claims 154-157, wherein the circumferentially adjacent cells have a peak-to-peak amplitude (width in the longitudinal direction) when in the support member in a delivery configuration in the range of 0.1 mm to 0.5 mm, preferably 0.15 mm to 0.4 mm, more preferably 0.15 mm to 0.35 mm.

159. A catheter as described in any one of claims 154-158, wherein each ring has 3 to 10 cells per mm of circumference, preferably 3 to 7 cells per mm of circumference, and most preferably 3 to 5 cells per mm of circumference.

160. A catheter as described in claims 154-159, wherein at least some of the rings in the support member have a ratio of (1) the number of bends to (2) the circumferential length, said ratio being in the range of 2 per mm to 15 per mm, preferably 3 per mm to 12 per mm, more preferably 4 per mm to 12 per mm, and most preferably 5 per mm to 12 per mm.

161. The catheter of claim 160, wherein the ratio is constant over at least a portion of the support member.

162. The catheter of claim 161, wherein the ratio varies across at least a portion of the support member.

163. A catheter according to any one of claims 154-162, wherein the ring, in the delivery configuration, spans a length, measured longitudinally, in the range of 0.2 mm to 400 mm.

164. A catheter according to any one of claims 154-163, wherein the gap between adjacent rings, in the delivery configuration, is in the range of 0.025 mm to 0.35 mm, measured in the longitudinal direction.

165. A catheter according to any one of claims 154-164, wherein the distal tip has 2 to 5 rings per mm of length, preferably 3 to 4 rings per mm of length.

166. The catheter of any one of claims 154-165, wherein at least some of the adjacent rings are continuously joined end-to-end in a helical pattern.

167. 167. The catheter of claim 166, wherein at least some of the adjacent rings in the helical pattern comprise nonlinearity.

168. 167. The catheter of claim 166, wherein all of the adjacent rings in the helical pattern are free of nonlinearity.

169. A catheter as described in claims 154-168, wherein adjacent rings, in the delivery configuration, are joined at an acute pitch angle relative to the longitudinal axis within the range of 80° to 89.9°, preferably 85° to 89° degrees, and more preferably 86° to 88°.

170. 170. The catheter of claim 169, wherein the pitch angle is constant along the length of the expandable support member.

171. The catheter of claim 170, wherein the pitch angle varies along the length of the expandable support member.

172. The catheter of any one of claims 154-171, wherein at least some of the adjacent rings are joined by axial connections or attachment points.

173. A catheter according to any one of claims 154-172, wherein at least some of the cells comprise a malleable metal or metal alloy configured to plastically deform.

174. The malleable metal may be cobalt chrome, e.g., L-605, MP35N, Stellite 6B, ASTM F1537 / F799 Alloy 1, ASTM F1537 / F799 Alloy 2. The catheter of claim 173, comprising a metal or metal alloy selected from the group consisting of stainless steel, e.g., 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L, and 420S, tantalum, niobium, tungsten, molybdenum, platinum, platinum-iridium alloys, e.g., Pt-10Ir, Pt-20Ir, and Pt-30Ir, nitinol, superelastic nitinol, magnesium, magnesium alloys, e.g., Mg-3A1-1Z, Mg-Zn-Se, and Mg-Zn-Cu, zinc, or the like.

175. The catheter of claim 174, wherein the malleable metal comprises a molybdenum alloy, for example a molybdenum-rhenium alloy comprising 90% to 100% molybdenum and rhenium.

176. The catheter of claim 175, wherein the molybdenum-rhenium alloy further comprises one or more metals selected from the group consisting of boron, calcium, chromium, cobalt, copper, gold, iron, lead, magnesium, manganese, mercury, nickel, niobium, platinum, rare earth metals, silicon, silver, sulfur, tantalum, tin, titanium, tungsten, yttrium, zinc, and zirconium.

177. A catheter according to any one of claims 154-176, wherein the radially contracted configuration has a maximum diameter in the range of 0.5 mm to 30 mm, and the radially expanded configuration has a minimum diameter in the range of 1.3 mm to 40 mm.

178. A catheter as described in claims 154-176, wherein the distal tip is configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to an outward radial expansion force applied within the distal tip.

179. A catheter as described in claims 154-176, wherein the distal tip is configured to expand from an initial cylindrical shape to an expanding conical configuration in response to an outward radial expansion force applied within the distal tip.

180. A catheter as described in claims 154-179, wherein the circumferentially adjacent cells in at least some of the rings in the distal tip have flat outer surfaces that define facets in a polygonal structure.

181. The catheter of claim 180, wherein the ring has a first radius from an axial centerline of the ring to a circumferential center of each facet and a second radius from the axial centerline of the ring to a circumferential edge of each facet, the length of the first radius being 97% to 99.9%, preferably 98% to 99.5%, and more preferably 98.5% to 98.5% of the length of the second radius.

182. A catheter according to any one of claims 154-181, wherein the tubular catheter body has a length from the proximal end to the distal end in the range of 50 cm to 200 cm, an outer diameter in the range of 0.5 mm to 30 mm, and an inner lumen diameter of 0.25 mm to 25 mm.

183. The catheter of any one of claims 154-182, wherein the tubular membrane comprises an elastic membrane.

184. The catheter of claim 183, wherein the elastic membrane comprises one or more elastomers.

185. The one or more elastomers may be selected from the group consisting of NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft ＴＭ 596-50A, NeuSoft NEU 455-55A, NeuSoft NEU 455-60A NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG 80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A Tecoflex TT-18095A, Elastollan S 50 A 15SPF Elastollan S 60 A 10W Elastollan S 60 A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane Rx50A, Texin RXT 70A, Chronoflex C 80A-Q, Chronoflex AL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 185. The catheter of claim 184, wherein the catheter is selected from the group consisting of ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex 00-30, Ecoflex 00-20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, Clonoprene, Chronocene, Clonosyl, combinations thereof, or equivalents.

186. A catheter as described in claims 183-185, wherein the elastic membrane has isotropic properties.

187. A catheter as described in claims 183-186, wherein the elastic membrane has anisotropic properties, the membrane being more elastic in the circumferential direction than in the axial direction.

188. The catheter of any one of claims 154-187, wherein the tubular membrane comprises an inelastic membrane.

189. The non-elastic membrane may be made of one or more polymers such as polyethylene, e.g., LDPE, HDPE, Ultra HMWPE, or equivalent; Pebax, e.g., Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, or equivalent; Nylon, e.g., Nylon 12, Nylon 6 / 6, or Nylon 6; Polyurethane, e.g., Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64 ... The catheter of claim 188, comprising a material selected from the group consisting of 72D, a fluoropolymer, e.g., PTFE, poly(vinylidene fluoride-co-hexafluoropropene), poly(vinylidene fluoride-co-hexafluoropropene), fluorinated ethylene propylene, polychlorotrifluoroethylene ethylene, or equivalents, or other polymers.

190. 190. A catheter as described in claim 188 or 189, wherein the inelastic membrane is configured to plastically deform as the support member expands.

191. A catheter as described in claims 188-190, wherein the membrane is configured to unfold as the support member expands.

192. A catheter as described in claims 154-191, wherein the distal tip is formed by heat shrinking the tubular membrane onto the expandable support member.

193. A catheter as described in claims 154-191, wherein the distal tip is formed by laminating the expandable support member between layers of the tubular membrane.

194. The catheter of claim 193, wherein the layers are joined to one another such that a seal exists between the layers.

195. A catheter as described in any one of claims 154-194, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter supporting member.

196. 191. The catheter of claim 190, wherein at least a portion of the catheter support member is continuous with the expandable support member.

197. A catheter as described in claims 154-196, further comprising a number of support elements, each support element having a base end and a free end, the base end attached to one of the radially expandable rings and the free end extending into an adjacent axial and / or circumferential gap.

198. 200. The catheter of claim 197, wherein at least some of the plurality of rings include struts joined by bends.

199. The catheter of claim 198, wherein at least some of the multiple support elements have their base ends attached to a post.

200. The catheter of claim 198, wherein at least some of the multiple support elements have their base ends attached to a bend.

201. 200. The catheter of claim 197, wherein at least some of the multiple support elements have their base ends attached to an inner surface of the ring.

202. 200. The catheter of claim 197, wherein at least some of the multiple support elements have their base ends attached to an outer surface of the ring.

203. A catheter according to any one of claims 197-202, wherein at least some of the multiple support elements have a constant width across their distal portions.

204. A catheter according to any one of claims 197-202, wherein at least some of the multiple support elements have variable widths across their distal portions.

205. A catheter according to any one of claims 197-204, wherein at least some of the multiple support elements have distal tips that extend into the adjacent circumferential gaps.

206. A catheter according to any one of claims 197-204, wherein at least some of the multiple support elements have distal tips that terminate flush with the bends that join the struts.

207. A catheter according to any one of claims 197-204, wherein at least some of the multiple support elements have distal tips recessed between adjacent bends joining the struts.

208. 1. A method for aspirating a blood clot from a patient's vascular system, the method comprising: Positioning a distal tip of an aspiration catheter according to any one of claims 154-208 in the region of the clot within the patient's vasculature; expanding the distal tip to its radially expanded configuration to engage a vessel wall adjacent the region of the clot; applying negative pressure to a proximal end of a lumen within the catheter body to aspirate the clot into a central passage of the expanded expandable structure; A method comprising:

209. 209. The method of claim 208, wherein a portion of the expandable support member remains at least partially unexpanded after expansion of another portion of the expandable support member.

210. 1. A suction catheter comprising: a tubular catheter body having a proximal end, a distal end and a lumen extending along a longitudinal axis; an expandable coil comprising continuous helical turns disposed along a longitudinal axis, the expandable coil comprising undulating bends and struts, the continuous turns having gaps therebetween, the continuous turns being tilted at an acute pitch angle with respect to the longitudinal axis; a housing disposed around the expandable coil; The suction catheter comprises:

211. The catheter of claim 210, wherein at least some of the adjacent rings in the helical arrangement comprise nonlinearity.

212. The catheter of claim 210, wherein all of the adjacent rings in the helical arrangement are free of nonlinearity.

213. The aspiration catheter of any one of claims 210-212, wherein the expandable coil is configured to be expanded by an expandable support structure radially expanded within the expandable coil.

214. 214. The aspiration catheter of claim 213, wherein the expandable coil is balloon expandable.

215. The aspiration catheter of any one of claims 210-214, wherein the expandable coil is formed, at least in part, from a malleable metal or metal alloy.

216. The aspiration catheter of any one of claims 210-215, wherein at least a proximal portion of the tubular catheter body is non-expandable.

217. The aspiration catheter of any one of claims 210-215, wherein at least a proximal portion of the tubular catheter body is radially expandable.

218. The aspiration catheter of any one of claims 210-217, wherein the expandable coil is attached to a reinforcing member or structure within the proximal section of the catheter body.

219. The aspiration catheter of claim 218, wherein the expandable coil and the reinforcing member are formed from a continuous wire or tube.

220. 220. An aspiration catheter according to any one of claims 210-219, wherein adjacent rings are joined at an acute pitch angle relative to the longitudinal axis within the range of 85° to 89.9°, preferably 86° to 89° degrees, more preferably 86° to 88°.

221. The aspiration catheter of any one of claims 210-220, wherein the expandable coil is attached to a distal end of the tubular catheter body.

222. The aspiration catheter of any one of claims 210-221, wherein an expandable coil is embedded within the tubular catheter body.

223. The aspiration catheter of any one of claims 210-222, wherein the expandable coil has a crimped delivery configuration and an expanded deployed configuration.

224. 224. The aspiration catheter of any one of claims 210-223, wherein in the crimped delivery configuration, the expandable coil has a maximum outer diameter in the range of 0.5 mm to 30 mm, and in the expanded deployed configuration, the expandable coil has a maximum outer diameter in the range of 0.5 mm to 40 mm.

225. The suction catheter of any one of claims 210-224, wherein the tubular catheter body has a length from the proximal end to the distal end in the range of 50 cm to 200 cm, an outer diameter in the range of 0.5 mm to 30 mm, and an inner lumen diameter of 0.25 mm to 25 mm.

226. 226. The aspiration catheter of any one of claims 210-225, wherein the expandable coil has a bending resistance in its initial radially contracted configuration of less than 1 N, preferably less than 0.5 N, more preferably less than 0.3 N, and a collapse pressure in its radially expanded configuration of 0.5 atm or greater, preferably 0.75 atm or greater, more preferably 1 atm or greater.

227. 227. The aspiration catheter of claim 226, wherein the bending resistance is measured by a 3-point flexure test, the span length is 13 mm, and the maximum deflection is 2.0 mm.

228. 228. The catheter of claim 226 or 227, wherein the collapse pressure is applied to the proximal end of the catheter body lumen with the distal tip of the catheter body lumen occluded.

229. The aspiration catheter of any one of claims 210-228, wherein the expandable coil has a minimum bend radius, without kinking, of 5 mm, preferably 3 mm, more preferably 2 mm in its radially contracted configuration, and a minimum bend radius, without kinking, of 10 mm, preferably 6 mm, more preferably 2 mm in its radially expanded configuration.

230. 230. An aspiration catheter according to any one of claims 210-229, wherein the continuous turn of the expandable coil spans a length, measured in the longitudinal direction, in the range of 0.5 mm to 200 mm, preferably in the range of 1 mm to 80 mm, more preferably in the range of 10 mm to 40 mm.

231. The aspiration catheter of any one of claims 210-230, wherein the expandable coil is comprised of between 5 and 725 continuous helical turns.

232. 232. The aspiration catheter of any one of claims 210-231, wherein the gap between adjacent turns of the expandable coil has a length, measured in the longitudinal direction, in the range of 0 mm to 0.64 mm, preferably 0.025 mm to 0.2 mm, more preferably 0.05 mm to 0.15 mm.

233. 233. The aspiration catheter of claim 232, wherein the length of the gap between adjacent turns of the expandable coil is constant.

234. 233. The catheter of claim 232, wherein the length of the gap between adjacent turns of the expandable coil is variable.

235. An aspiration catheter according to any one of claims 210-234, wherein the expandable coil has at least 2 rings per mm of length, preferably at least 3 rings per mm of length, typically 2-5 rings per mm of length, more typically 3-5 rings per mm of length.

236. The malleable metal may be cobalt chrome, e.g., L-605, MP35N, Stellite 6B, ASTM F1537 / F799 Alloy 1, ASTM F1537 / F799 Alloy 2. The aspiration catheter of any one of claims 210-235, comprising a metal or metal alloy selected from the group consisting of stainless steel, e.g., 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L, and 420S, tantalum, niobium, tungsten, molybdenum, platinum, platinum-iridium alloys, e.g., Pt-10Ir, Pt-20Ir, and Pt-30Ir, nitinol, superelastic nitinol, magnesium, magnesium alloys, e.g., Mg-3A1-1Z, Mg-Zn-Se, and Mg-Zn-Cu, zinc, or the like.

237. 237. The aspiration catheter of claim 236, wherein the malleable metal comprises a molybdenum alloy, for example a molybdenum-rhenium alloy comprising 90% to 100% molybdenum and rhenium.

238. The catheter of claim 237, wherein the molybdenum-rhenium alloy further comprises one or more metals selected from the group consisting of boron, calcium, chromium, cobalt, copper, gold, iron, lead, magnesium, manganese, mercury, nickel, niobium, platinum, rare earth metals, silicon, silver, sulfur, tantalum, tin, titanium, tungsten, yttrium, zinc, and zirconium.

239. The aspiration catheter of any one of claims 210-238, wherein the outer covering comprises an elastic membrane.

240. 240. The aspiration catheter of claim 239, wherein the elastic membrane comprises one or more elastomers.

241. The one or more elastomers may be selected from the group consisting of NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft ＴＭ 596-50A, NeuSoft NEU 455-55A, NeuSoft NEU 455-60A NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG 80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A Tecoflex TT-18095A, Elastollan S 50 A 15SPF Elastollan S 60 A 10W Elastollan S 60 A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane Rx50A, Texin RXT 70A, Chronoflex C 80A-Q, Chronoflex AL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex 00-30, Ecoflex 00-20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, Clonoprene, Chronocene, Clonosyl, combinations thereof, or equivalents.

242. The aspiration catheter of claims 239-241, wherein the elastic membrane has isotropic properties.

243. An aspiration catheter as described in claims 239-242, wherein the elastic membrane has anisotropic properties, the membrane being more elastic in the circumferential direction than in the axial direction.

244. The aspiration catheter of any one of claims 210-243, wherein the outer covering comprises an inelastic membrane.

245. The non-elastic membrane may be made of one or more polymers such as polyethylene, e.g., LDPE, HDPE, Ultra HMWPE, or equivalent; Pebax, e.g., Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, or equivalent; Nylon, e.g., Nylon 12, Nylon 6 / 6, or Nylon 6; Polyurethane, e.g., Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64 ... 72D, a fluoropolymer, e.g., PTFE, poly(vinylidene fluoride-co-hexafluoropropene), poly(vinylidene fluoride-co-hexafluoropropene), fluorinated ethylene propylene, polychlorotrifluoroethylene ethylene, or equivalents, or other polymers.

246. 246. The aspiration catheter of claim 244 or 245, wherein the inelastic membrane is configured to plastically deform as the coil expands.

247. The aspiration catheter of any one of claims 244-246, wherein the membrane is configured to unfold as the coil expands.

248. The aspiration catheter of any one of claims 210-247, wherein the outer jacket is formed by heat shrinking the outer jacket onto the expandable coil.

249. An aspiration catheter as described in claims 210-247, wherein the outer jacket is formed by laminating the expandable coil between layers of the outer jacket.

250. 250. The aspiration catheter of claim 249, wherein the layers are joined to one another such that a seal exists between the layers.

251. The aspiration catheter of any one of claims 210-250, wherein the outer covering comprises at least two membrane compartments.

252. The aspiration catheter of claim 251, wherein the at least two membrane compartments comprise a single type of material.

253. The aspiration catheter of claim 251, wherein the at least two membrane compartments comprise at least two types of material.

254. The aspiration catheter of any one of claims 251-253, wherein the at least two membrane sections cover at least an outer surface of the expandable coil.

255. The aspiration catheter of any one of claims 251-253, wherein the at least two membrane compartments cover at least the inner surface of the expandable coil.

256. The aspiration catheter of any one of claims 251-253, wherein the at least two membrane compartments cover both the inner and outer surfaces of the expandable coil.

257. An aspiration catheter as described in claims 210-256, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter supporting member.

258. 258. The aspiration catheter of claim 257, wherein the catheter supporting member is continuous with the expandable coil.

259. The aspiration catheter of claim 258, wherein the catheter supporting member and the expandable coil are patterned from the same tube.

260. The aspiration catheter of claim 258, wherein the catheter supporting member and the expandable support member are formed from one or more bent wires and span at least a portion of the catheter supporting member and the expandable coil, respectively.

261. The aspiration catheter of claims 210-260, further comprising a number of support elements, each support element having a base end and a free end, the base end attached to one of the expandable coil turns and the free end extending into an adjacent circumferential gap.

262. 262. The aspiration catheter of claim 261, wherein at least some of the multiple support elements have a constant width across their distal portions.

263. 262. The aspiration catheter of claim 261, wherein at least some of the multiple support elements have variable widths over their distal portions.

264. 1. An aspiration catheter configured to resist kinking when delivered through a patient's vasculature, the aspiration catheter comprising: a tubular catheter body having a proximal end, a distal end and a lumen extending therebetween; a radially expandable distal tip at a distal end of the tubular catheter body, the radially expandable distal tip having a delivery radius and a central passageway continuous with a lumen of the tubular catheter body, the radially expandable distal tip comprising: (a) an expandable support structure comprising a plurality of radially expandable circumferential rings arranged along a longitudinal axis with circumferential gaps therebetween, at least some of the expandable rings comprising cells including struts joined by crowns arranged continuously end-to-end in a helical pattern; (b) a membrane covering an exterior surface of the expandable support structure; and a radially expandable distal tip comprising: Equipped with an outer surface area of ​​the membrane supported by cells has a radius R measured from a longitudinal axis of the expandable support structure; a flat facet in an outer surface of the membrane spanning a gap between circumferentially adjacent cells has a radius r measured from a longitudinal axis of the expandable support structure; the outer surface of the membrane maintains at least 97% circularity, measured as r / R×100, after the expandable support structure is radially expanded up to 200% from the delivery radius. Suction catheter.

265. The aspiration catheter of claim 264, wherein the outer surface of the membrane maintains at least 97% circularity, measured as r / R x 100, after the expandable support structure is radially expanded up to 100% from the delivery radius.

266. The aspiration catheter of claim 264, wherein the outer surface of the membrane maintains at least 97% circularity, measured as r / R x 100, after the expandable support structure is radially expanded up to 50% from the delivery radius.

267. The aspiration catheter of any one of claims 264-266, wherein the outer surface of the membrane maintains at least 98% circularity, measured as r / R x 100, after the expandable support structure is radially expanded from the delivery radius.

268. The aspiration catheter of any one of claims 264-266, wherein the outer surface of the membrane maintains at least 98.5% circularity, measured as r / R x 100, after the expandable support structure is radially expanded from the delivery radius.

269. An aspiration catheter as described in any one of claims 264-268, wherein in a spiral pattern, the circumferential rings arranged along the longitudinal axis have an acute pitch angle in the range of 70° to 89.9° when the radially expandable distal tip is at its delivery radius.

270. An aspiration catheter as described in any one of claims 264-268, wherein in a spiral pattern, the circumferential rings arranged along the longitudinal axis have an acute pitch angle in the range of 80° to 89° when the radially expandable distal tip is at its delivery radius.

271. An aspiration catheter as described in any one of claims 264-268, wherein in a spiral pattern, the circumferential rings arranged along the longitudinal axis have an acute pitch angle in the range of 85° to 88° when the radially expandable distal tip is at its delivery radius.

272. An aspiration catheter as described in any one of claims 264-271, wherein at least some of the circumferential rings arranged along the longitudinal axis in a helical pattern have a cell period within the range of 0.1 mm to 1.2 mm when the radially expandable distal tip is at its delivery radius.

273. An aspiration catheter as described in any one of claims 264-271, wherein at least some of the circumferential rings arranged along the longitudinal axis in a helical pattern have a cell period within the range of 0.15 mm to 0.4 mm when the radially expandable distal tip is at its delivery radius.

274. An aspiration catheter as described in any one of claims 264-271, wherein at least some of the circumferential rings arranged along the longitudinal axis in a helical pattern have a cell period within the range of 0.2 mm to 0.35 mm when the radially expandable distal tip is at its delivery radius.

275. The aspiration catheter of any one of claims 264-274, wherein at least some of the circumferential rings arranged along the longitudinal axis in a spiral pattern have a number of crowns within each ring in the range of 4 per mm of circumference to 15 per mm of circumference when the radially expandable distal tip is at its delivery radius.

276. The aspiration catheter of any one of claims 264-274, wherein at least some of the circumferential rings arranged along the longitudinal axis in a spiral pattern have a number of crowns within each ring in the range of 5 per mm of circumference to 15 per mm of circumference when the radially expandable distal tip is at its delivery radius.

277. An aspiration catheter as described in any one of claims 264-276, wherein at least some of the circumferential rings arranged along the longitudinal axis in a spiral pattern have a cell peak-to-peak distance (cell amplitude) within the ring when the radially expandable distal tip is at its delivery radius within the range of 0.05 mm to 0.35 mm.

278. An aspiration catheter as described in any one of claims 264-276, wherein at least some of the circumferential rings arranged along the longitudinal axis in a spiral pattern have a cell peak-to-peak distance (cell amplitude) within the ring when the radially expandable distal tip is at its delivery radius within the range of 0.1 mm to 0.25 mm.

279. An aspiration catheter as described in any one of claims 264-276, wherein at least some of the circumferential rings arranged along the longitudinal axis in a spiral pattern have a cell peak-to-peak distance (cell amplitude) within the ring when the radially expandable distal tip is at its delivery radius within the range of 0.1 mm to 0.2 mm.

280. 280. An aspiration catheter according to any one of claims 264-279, wherein the ratio of the arc length of the bend to the axial length of the strut is in the range of 0.2:1 to 2:

1.

281. An aspiration catheter as described in any one of claims 264-279, wherein the ratio of the arc length of the bend to the axial length of the strut is in the range of 0.5:1 to 1.5:

1.

282. 280. An aspiration catheter according to any one of claims 264-279, wherein the ratio of the arc length of the bend to the axial length of the strut is in the range of 0.75:1 to 1.25:

1.

283. An aspiration catheter as described in any one of claims 264-282, wherein at least some of the cells in each ring have no axial connection to axially adjacent rings.

284. An aspiration catheter according to any one of claims 264-282, wherein at least some of the rings have a constant peak-to-peak spacing of cells (cell amplitude) within the ring.

285. 285. The aspiration catheter of any one of claims 264-284, wherein the distal tip, in its delivery configuration, has a bending resistance of less than 1 N as measured by a 3-point flexure test.

286. 285. The aspiration catheter of any one of claims 264-284, wherein the distal tip, in its delivery configuration, has a bending resistance of less than 0.5 N as measured by a 3-point flexure test.

287. 285. The aspiration catheter of any one of claims 264-284, wherein the distal tip, in its delivery configuration, has a bending resistance of less than 0.3 N as measured by a 3-point flexure test.

288. 285. The aspiration catheter of any one of claims 264-284, wherein the distal tip, in its delivery configuration, has a bending resistance of less than 0.2 N as measured by a 3-point flexure test.

289. An aspiration catheter as described in any one of claims 264-288, wherein the distal tip has a collapse pressure (vacuum) of 0.5 atm or greater in its radially expanded configuration when a vacuum is attached to the proximal end of the aspiration lumen and the open distal end of the distal tip is blocked.

290. An aspiration catheter as described in any one of claims 264-288, wherein the distal tip has a collapse pressure (vacuum) of 0.75 atm or greater in its radially expanded configuration when a vacuum is attached to the proximal end of the aspiration lumen and the open distal end of the distal tip is blocked.

291. An aspiration catheter as described in any one of claims 264-288, wherein the distal tip has a collapse pressure (vacuum) of 1 atm in its radially expanded configuration when a vacuum is attached to the proximal end of the aspiration lumen and the open distal end of the distal tip is blocked.

292. The aspiration catheter of any one of claims 264-291, wherein the distal tip is configured to be expanded by a balloon catheter.

293. 300. The aspiration catheter of claim 292, wherein the distal tip is configured such that the balloon catheter can expand over all or a portion of the axial length of the distal tip.

294. The aspiration catheter of any one of claims 264-293, further comprising a number of support elements, each support element having a base end and a free end, the base end attached to one of the radially expandable rings, and the free end extending axially and / or circumferentially away from the one of the radially expandable rings.

295. 300. The catheter of claim 294, wherein at least some of the free ends of the support elements are recessed within the circumferential ring and do not protrude into the circumferential gap prior to radial expansion of the distal tip.

296. 300. The catheter of claim 295, wherein at least some of the free ends of the support elements protrude into the circumferential gap after expansion of the distal tip.

297. A catheter according to any one of claims 294-296, wherein the base end is attached to an inner radius of the crown of the cell and the free end extends between the struts of the cell.

298. A catheter described in any one of claims 294-296, wherein the support element is configured to fit within a cylindrical outer shell defined by the expandable support structure prior to expansion.

299. The catheter of any one of claims 264-298, wherein the membrane comprises an elastic membrane.

300. A catheter described in any one of claims 264-299, wherein the membrane covers at least an outer surface of the expandable support structure.

301. A catheter described in any one of claims 264-300, wherein the membrane covers at least the inner surface of the expandable support structure.

302. A catheter described in any one of claims 264-301, wherein the membrane comprises one or more elastomers.

303. The catheter of claim 299, wherein the expandable support structure is embedded or laminated within the elastic membrane.

304. An aspiration catheter as described in any one of claims 264-303, wherein at least some of the circumferential rings arranged along the longitudinal axis in the spiral pattern have both a cell period and a cell amplitude (peak-to-peak axial distance) of 0.25 mm ± 0.2 mm when measured in the delivery configuration.

305. An aspiration catheter as described in any one of claims 264-303, wherein at least some of the circumferential rings arranged along the longitudinal axis in the spiral pattern have both a cell period and a cell amplitude (peak-to-peak axial distance) of 0.25 mm ± 0.15 mm when measured in the delivery configuration.

306. An aspiration catheter as described in any one of claims 264-303, wherein at least some of the circumferential rings arranged along the longitudinal axis in the spiral pattern have both a cell period and a cell amplitude (peak-to-peak axial distance) of 0.25 mm ± 0.1 mm when measured in the delivery configuration.

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