Suction catheter with expandable distal tip

Abstract

The aspiration catheter includes a catheter body having a proximal end, a distal end, and an aspiration lumen between the proximal end and the distal end. A distal section of an aspiration catheter comprising an expandable distal tip includes a membrane and an expandable support structure, such as a stent, configured to radially expand the expandable distal tip. The expandable support structure may include support elements and other features that increase resistance to collapse of the expandable membrane upon application of a vacuum or negative pressure to aspirate clots through the aspiration lumen in the expanded configuration.

Description

[0001] Cross-references

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 324,540 filed on March 28, 2022 (32016-730.101), U.S. Provisional Application No. 63 / 327,326 filed on April 4, 2022 (32016-730.102), and U.S. Provisional Application No. 63 / 487,773 filed on March 1, 2023 (Agent Docket No. 32016-730.103), the entire contents of each of which are incorporated herein by reference. Background Art

[0003] 1. Field of the Invention :The present application generally relates to medical devices and methods of using the same. More specifically, the present invention relates to devices and methods for removing clots from the brain and other vasculature of a patient.

[0004] Every year, millions of people around the world suffer strokes caused by blood clots in the brain. Even if not fatal, these clots can cause severe and permanent disability. Until recently, the only way to treat patients who presented with symptoms of an occlusive stroke was with medication, in which the patient was given an intravenous injection of tissue plasminogen activator (tPA) to dissolve the clot and restore blood flow in the brain. However, because vascular thrombi (clots) tend to become more fibrotic and / or hardened over time, the window of efficacy of tPA is only a few hours after the clot first forms. Given the time required to identify that an individual may have had a stroke, get them to a hospital, and perform the diagnosis and administer treatment, many patients' clots are too mature to respond to tPA, leaving perhaps two-thirds or more of stroke victims without significant help from medical treatment.

[0005] Advances in medical technology have led to the development of various mechanical thrombectomy procedures, in which a blood clot is physically removed from the brain. Mechanical thrombectomy offers a significant advantage over medical therapy in that it can remove a clot hours after the window of efficacy of medical therapy has passed and still provide benefit to the patient.

[0006] There are two main approaches to mechanical thrombectomy, which can be used alone or in combination with each other, depending on patient characteristics and physician preference. The first is to apply a vacuum to the clot using a catheter, a technique called direct aspiration. The second is to capture and physically extract the clot using a stent retriever, optionally combined with applying a vacuum to the clot via a separate aspiration catheter.

[0007] Both mechanical thrombectomy approaches have their limitations. While stent retrievers are small and flexible enough to approach most clots, thereby engaging and capturing the clot, their ability to capture and remove the clot varies and is limited. In some cases, only a portion of the clot can be removed, and debris generated by the procedure may be released downstream, causing secondary occlusions. Stent retrievers can also be traumatic to the vessel as they are typically towed proximally in an expanded configuration, pulling the clot along with it but potentially causing trauma to the vessel. The retriever struts can scrape the endothelium on the vessel wall, creating areas that are more susceptible to future occlusions. Procedural time is also an issue with stent retrievers as, in addition to delivery and retrieval time, they often require considerable time to stabilize and secure the clot before the first removal attempt can be made. In the ischemic brain tissue environment, differences in procedural time can have very important clinical implications for successful outcomes.

[0008] The effectiveness of an aspiration catheter depends on the ability of the catheter to aspirate the clot using a vacuum through the catheter's aspiration lumen, and varies depending on the type, size, location of the clot and the inner diameter of the catheter lumen through which the clot is removed. Although a larger inner diameter aspiration catheter is needed to successfully and consistently remove a clot, at least some of the following still hinder this desired design, such as reduced catheter flexibility, inability to reach the desired anatomical structure to remove the clot, inability to resist collapse under vacuum, and / or inability of such a catheter to enter a blood vessel using current accessory access devices. The diameter of current aspiration catheters is limited by the size of the accessory devices (e.g., hemostatic valves, introducers, and guide membranes / catheters) that the physician uses to introduce the aspiration catheter into the anatomical structure, and is limited by its ability to pass through and reach the location of the clot. Therefore, many aspiration catheters currently used for neurovascular occlusive stroke, for example, typically have an inner diameter of about 0.072 inches. Since most clots tend to be much larger than the aspiration catheter size, the small size of conventional aspiration catheters poses a challenge to successful aspiration as they fail to aspirate the clot completely on the first vacuum aspiration attempt, or fail to aspirate the clot at all, and are unable to disrupt or fragment the clot.

[0009] In order to enhance suction and still fit within an access device, some neurovascular occlusive clot aspiration catheters for clot retrieval have been developed with larger lumen diameters, such as 0.088" aspiration catheters. However, these catheters tend to be bulkier and have poorer delivery capabilities, affecting their ability to reach many clot locations and / or taking longer to reach a clot location.

[0010] Due to their bulk, current aspiration catheters are often limited in their ability to traverse the tortuous anatomy of the brain to reach commonly targeted occluded segments. Due to the bulk of these catheters and the highly tortuous neurovascular anatomy, these catheters are unable to successfully reach even more distal clots. Smaller aspiration catheters designed specifically for easier delivery and / or access to more distal clots are often unable to retrieve clots due to insufficient suction force at the tip due to the smaller tip area, and / or because the aspiration lumen of the smaller catheter is too small / too narrow to aspirate or retrieve the clot.

[0011] To improve delivery capabilities and accommodate accessory devices while maintaining the ability to retrieve larger clots, many clot aspiration catheters have an expandable distal tip that provides a larger distal opening and a smaller body size. While an improvement overall, such an expandable tip may collapse when negative pressure (vacuum) is applied to aspirate the clot, thereby compromising its ability to retrieve the clot.

[0012] To reduce the risk of collapse, some expandable tips have been reinforced with expandable metal and other stents, but even with such reinforced stents, the expandable segment of the aspiration catheter may still deform or collapse significantly in the expanded configuration due to the applied negative pressure (vacuum), and / or become stiffer, thereby compromising its delivery ability, and / or be prone to deformation or kinking when advanced into the anatomical structure in the delivery configuration, thereby compromising the integrity of the aspiration lumen.

[0013] What is needed is: a device that is flexible in its delivery configuration to enhance delivery to reach clots in anatomical structures containing clots, such as the brain in proximal and distal neuroanatomy or other vascular anatomy; a device that is capable of removing clots without fragmenting the clot or substantially fragmenting the clot; a device that is capable of removing clots without causing secondary occlusions; a device that is capable of reliably removing clots without the use of stent retrievers or other auxiliary devices; a device that is capable of reaching an occlusion and quickly retrieving a clot; a device that does not scrape or otherwise traumatize the vessel wall at any point during the procedure; a device that successfully retrieves a clot during the first aspiration attempt; and a device that is capable of reliably removing a clot without the use of a stent retriever or other auxiliary device. A device that can capture debris that has broken off from an original clot; a device having an expandable distal tip that resists deformation in an expanded configuration so as to substantially maintain the aspiration lumen configuration in the expanded configuration under vacuum to aspirate a clot, and / or a device having an expandable tip that resists collapse in an expanded configuration even when exposed to high vacuum pressures during aspiration of a clot; a device that resists deformation or kinking in a delivery configuration when traversing vascular anatomy; a device that can be retracted to a smaller configuration after expansion to an expanded configuration; and / or a device having an expandable distal tip aspiration lumen, wherein the distal tip aspiration lumen is configured to maximize lumen area or configuration in the expanded configuration. The present invention will meet at least some of these needs.

[0014] 2. Background technology list . Related patents and applications include US2022 / 0125450 and 18 / 156,921, which are commonly owned with this application, and the entire disclosures of which are incorporated herein by reference. Other related patents and patent disclosures 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 19 / 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. Summary of the invention

[0015] In the first aspect, the present invention provides a kind of suction catheter (such as but not limited to brain suction catheter, coronary artery suction catheter, arterial suction catheter or venous suction catheter), it comprises a tubular catheter body with a suction cavity extending between a proximal end, a distal end and a proximal end and a distal end. The suction catheter has an expandable distal tip, and the expandable distal tip has a central channel (or channel) connected to the suction cavity of the tubular catheter body. An expandable support structure is attached to the expandable distal tip of the tubular catheter body, embedded in the expandable distal tip of the tubular catheter body or otherwise coupled to the expandable distal tip of the tubular catheter body. In some cases, the expandable support structure can be attached to the outer surface or inner surface of an expandable membrane, but more commonly it will be embedded or laminated in the expandable membrane, and the expandable membrane is such as a polymer membrane comprising one, two, three or more layers and composed of one, two, three or more polymer materials or other materials.

[0016] The phrase "distal tip" used herein and in the claims refers to the length or area at the distal end of the suction catheter. The distal tip will typically be constructed to be different from the proximal region or shaft of the suction catheter. In particular, the distal tip will typically be constructed to expand from a small diameter or from a low profile structure or from a delivered structure or from a delivered structure to a large diameter or a larger structure or an expanded structure or an expanded structure, or an enhanced removal structure, when a vacuum is applied at the proximal end of the suction catheter and the distal tip engages with the clot, it has a greater clot suction force or clot removal force, wherein the expansion (or expansion) structure of the distal tip remains substantially the same (or remains substantially expanded or expanded) when a vacuum is applied, thereby resisting collapse, typically, it is balloon expandable but sometimes self-expanding. In contrast, the proximal region or shaft typically has a fixed diameter along its length. The fixed diameter of the proximal region or shaft can be constant or can vary along its length. The distal tip in the delivery configuration can be a first clot retrieval configuration, while the distal tip in the expanded configuration can be a second clot retrieval configuration, wherein the second clot retrieval configuration has a greater retrieval force than the first clot retrieval configuration. In other examples, the expanded configuration can be the clot retrieval configuration, or can be a preferred clot retrieval configuration because it typically has enhanced clot retrieval force. The distal tip typically terminates at the distal end of the aspiration catheter.

[0017] The support structure is typically in the form of a stent and is configured to allow radial expansion of the expandable membrane, typically by applying radial outward expansion placed within the support structure using a balloon or other expandable member, and, particularly when the distal tip engages with a clot (or is blocked or obstructed by a clot) and a vacuum is applied through a suction lumen, the support structure is configured to enhance the resistance to collapse of the expandable membrane, that is, to resist or prevent collapse of the expandable membrane or reduce the lumen structure of the expandable membrane after the expandable support stent is expanded to the expanded structure, or when a vacuum is applied at the proximal end of the suction lumen while engaging with a clot, the support stent substantially maintains the expanded lumen structure of the expandable membrane.

[0018] The support structure typically includes a plurality of radially expandable rings arranged along the longitudinal axis, with gaps (forming circumferential gaps between adjacent rings) between the plurality of radially expandable rings. The radially expandable rings typically will include circular, square, rectangular, elliptical, spiral or other annular ring elements, wherein the annular ring elements are configured to non-elastically elongate (along their bending lengths) to allow distal tip circumferential expansion. Exemplary ring elements can be formed as serpentine, serrated rings, box-shaped (square or rectangular), diamond or other patterns, which include a curved portion that is not elastically opened in response to a radially outward force provided by a balloon or other expandable deployment member or structure. Exemplary rings can be an open cell design, a closed cell design, a combination of open and closed cell designs or other. Exemplary ring designs can be formed by a tubular body, a curved line, a patterned sheet rolled into a tubular shape, or formed by printing or other.

[0019] Exemplary open cell support structures can include serpentine and zigzag ring patterns comprising struts connected by crowns, wherein the crowns include a "bend" that opens non-elastically to allow radial and circumferential ring expansion. Although each circular or circumferential ring can have an even or odd number of crowns and struts, each side or face of the ring can 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 is 14 when counting both sides or faces of the ring. When the support structure does not include additional support elements, or when the support structure unit within a ring, or a unit within a plurality of rings, or a unit within each ring includes several support elements or includes at least some but not all support elements, a higher number of crowns of 60, 80, 100, 120, 1400, 1600, 180, 200 and 400 and above is preferred, as described below. When the support structure includes at least some or a large number of support elements per ring, per at least some adjacent rings, or per ring of the expandable tip, a lower number of crowns (such as 14, 22, 26, 30, 32, 34, 38, 40, 42, 48, 60 and 80) is generally sufficient. 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 (1) a greater number of crowns or other bends in the absence of a support element and (2) a smaller number of crowns in combination with a support element will enhance the roundness of the rings in the distal tip in both the delivery configuration and the expansion configuration, thereby maximizing the available aspiration lumen area. The phrase "the number of crowns or bends per ring" refers to the total number of crowns or bends counted around a single 360° rotation of each ring. Although the "number of crowns or bends per ring" will generally be constant for each ring in an open cell support structure, in some cases, the number may vary from ring to ring. The enhanced roundness of the distal tip (expandable support structure and expandable membrane) in the expansion configuration can increase the aspiration lumen area, increase vacuum force, and resist lumen collapse and deformation when a vacuum is applied at the proximal end of the aspiration lumen and the distal tip engages a clot (or when the distal tip is blocked or clogged by a clot or other material). In addition, the enhanced roundness resists deformation and / or kinking of the expandable distal tip in the delivery configuration as the catheter is advanced into the vascular system. By having a small cell period and / or a small cell amplitude, the maximized circularity of the ring can be further enhanced. In a preferred example, the expandable support structure includes a plurality of rings, wherein at least some of the rings (preferably substantially all of the rings) are configured to have a large number of crowns, small cell periods, and small cell amplitudes to have enhanced circumferential circularity.

[0021] In a preferred ring pattern (e.g., such as a serpentine pattern) comprising struts connected by crowns, the ratio of (1) the number of bends (e.g., crowns) per ring to (2) the circumference (outer edge) of the ring measured in millimeters (mm) is typically at least 3 crowns or bends per mm of circumferential length, often 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 or a high ratio of crowns or bends to circumferential length in each ring (or in some cases in a majority of rings or in other cases in multiple rings) improves the roundness of the distal tip (including the expandable support structure and the expandable membrane) in the expanded configuration, increases the suction chamber area or maximizes the chamber area, enhances the vacuum force, and resists collapse of the distal tip when vacuum is applied to the proximal end of the suction chamber and the distal tip engages with a clot. In addition, when vacuum is applied at the proximal end of the suction chamber and the distal tip engages with a clot (or is blocked by a clot or other material), the number of crowns or a high ratio of crowns to circumferential length increases the resistance to collapse of the distal tip including the expandable membrane and the expandable support structure. In addition, having a small unit period further enhances roundness. In addition, having a small unit amplitude can further enhance roundness.

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

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

[0024] Although the box will typically be square, diamond or rectangular, the box may have any closed polygonal structure comprising a plurality of straight sides (sometimes curved sides) connected by bends. In some cases, circular and elliptical closed shapes may also be considered as boxes within the scope of the present invention. Such a box structure will be configured to elongate (expand) circumferentially when a radial opening force is applied inside the support structure in the distal tip of the aspiration catheter.

[0025] In a preferred example, the expandable distal tip including 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 structure, or the expandable distal tip including the expandable support structure has an outer diameter in the range of 1 mm to 5 mm in the delivery structure. In other examples, the distal tip including the expandable support structure has an outer diameter of about 7 mm, 8 mm, 9 mm or about 10 mm in the delivery structure. Typically, the distal tip has a cylindrical shape in the delivery structure. In some other examples, the distal tip can have other shapes in the delivery structure, such as funnel-shaped, conical, rectangular, elliptical or other shapes. In yet another example, the distal tip includes an expandable support structure, wherein the distal tip has a cylindrical shape, a rectangular shape, an elliptical shape, a conical shape, a funnel shape or other shapes in the extended structure, wherein the outer diameter of the distal tip in the extended structure ranges from 2 mm to 10 mm, preferably ranges from 3 mm to 8 mm, and more preferably ranges from 3 mm to 7 mm. The outer diameter of the distal tip may vary along the length of the distal tip or around the circumference of the distal tip, or may be fixed or constant along the length of the distal tip or around the circumference of the distal tip.

[0026] In some cases, stent or other support structure will also include support elements, which will help support the space opened in the support structure when the support structure expands. For example, in a support structure including a serpentine ring comprising a crown and a pillar, when the ring expands, the pillar will separate and leave an unsupported space or gap therebetween. Before and after the support structure radially expands, the gap between adjacent rings will also be an unsupported space. The film will lack support in those gaps, and the roundness and / or compressive strength (compression resistance) of the distal tip of the expansion will all be reduced. In addition, when negative pressure is applied to the suction chamber of the catheter when engaging a clot, particularly when the distal tip of the opening is partially or completely blocked by the clot, or when the expandable tip is delivered to the vascular system in the delivery structure, this unsupported region of the film will face a greater risk of invagination (film and / or expandable support structure collapse or partial collapse).

[0027] The support elements of the present invention will be configured to fill as much open space as possible within the rings. In contrast, the spaces or gaps between axially adjacent rings will preferably be free of support elements (although in some examples there are typically axial links and other portions of support structure, and in other examples, the spaces or gaps between axially adjacent rings may be free of any support elements or attachment points and free of any portion of support structure). The spaces between adjacent rings should have the minimum number of support structures, if any, to enhance flexibility, particularly in unexpanded delivery configurations.

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

[0029] The preferred support element will be "overhanging" from the ring and configured to fill or support the opening or gap within the "axial width" of the ring, usually remaining outside the gap and space between adjacent rings, so as to support the distal tip after the distal tip is radially expanded without significantly reducing the flexibility of the distal tip when it is advanced into the vascular system, or without reducing the flexibility of the distal tip when it is advanced into the vascular system, or while maintaining the flexibility of the distal tip when it is advanced into the vascular system. An exemplary support element has a base end (proximal end) and a free end (distal end). The base end is usually attached to one of the radially expandable rings (e.g., attached to a ring structural element, such as a crown or a strut), and the free end is usually toward the gap between adjacent rings, and usually does not extend into the gap between adjacent rings in the delivery structure. In a preferred example, the expandable support structure includes a plurality of support elements within each ring, each of which has a width, length and thickness sufficient to support the unsupported space (or area) within the ring to prevent the unsupported area from collapsing or invagination (partial collapse) when a vacuum is applied to remove the engaged clot at the distal end of the suction catheter. In another example, the expandable support structure includes a plurality of circumferential rings, at least some of which include a plurality of support elements configured to resist collapse or invagination of unsupported areas when a vacuum is applied at the proximal end and the clot engages the distal end of the aspiration catheter. In yet another example, the expandable support structure includes a plurality of circumferential rings, at least some of which include at least some support elements configured to resist collapse or invagination of unsupported areas when a vacuum is applied at the proximal end and the clot engages the distal end of the aspiration catheter.

[0030] In some cases, the support elements may extend into adjacent gaps between adjacent rings even before the distal tip is radially expanded, 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 unit) before the rings are expanded, and to extend further, protrude further, or emerge toward or into adjacent gaps between adjacent rings when the distal tip is radially expanded (or only after the distal tip is radially expanded, or during the distal tip radial expansion). It has been found that the presence of support structures in the gaps between adjacent rings before the distal tip is expanded will reduce the flexibility of the tip during advancement in the vasculature before the distal tip is deployed. This loss of flexibility is undesirable.

[0031] Such "cantilevered" support elements are used as "support for unsupported areas or gaps within the axial width of the rings," and are deployed to enhance support for the expandable membrane after the distal tip is deployed 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 support elements also allows for increased expansion of the distal tip (thereby increasing the available aspiration lumen diameter) while resisting collapse when a vacuum is applied at the proximal end of the aspiration lumen. In another example, as the distal tip is expanded (or after the distal tip is expanded), the support element is deployed toward (or protrudes, or further extends) the gap between two adjacent rings, or deployed into the gap between two adjacent rings, to enhance support for the expandable membrane after the distal tip is deployed 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 element can have a variety of shapes and configurations, such as I, T, U, M, Z, curved, straight or other shapes and configurations to support or enhance the support of the unsupported segment of the expandable membrane, preferably without increasing the stiffness of the distal tip. The free end can have a flat shape, a circle, a sphere or other shape. The width of the support element can be the same or different along the length of the support element. The support element can be tapered, and its width increases or decreases in the direction from the attached base end to the free distal end.

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

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

[0035] In another preferred example, the support element is recessed into the space between structural elements of the ring, for example, the space between struts connected by crowns, so that in the delivery structure, the distal end of the support element does not substantially extend beyond the peaks of adjacent crowns or other structural elements and into the gaps between adjacent rings.

[0036] In specific examples, the support element may have a base end and a free end, two free distal ends, three free distal ends, or more.

[0037] In another example, the support element may have two or more base ends, each base end being attached to one or more structural elements on a ring (the same ring). Such a support element may have one, two, three or more distal free ends.

[0038] In another example, the support element can be divided into two parts to have at least two base ends, each base end is attached to a different structural element on a single ring. The base end of the support element can be attached to the axial inner surface or the axial outer surface of the ring, or to the axial inner surface or the axial outer surface of the structural element of the ring (including the crown, strut or connecting rod).

[0039] In a specific example, the radially expandable ring is arranged in a cylindrical "envelope" prior to expansion. The cylindrical envelope is a virtual space having an inner generally cylindrical surface and an outer generally cylindrical surface and an annular volume therebetween, wherein the radially expandable ring is sized and arranged to be located within the space prior to expansion. Typically, the support element is also configured to be located within the virtual cylindrical envelope prior to the ring expansion. The diameter of the cylindrical envelope may be greater than, equal to, or less than the diameter of the tubular catheter body prior to expansion.

[0040] In a specific example, the distal tip of the expandable support structure can be configured to expand into a cylinder, a cone, or a combination thereof after expanding to an extended structure. In a preferred example, the distal tip of the expandable support structure can be configured to expand from a cylindrical structure to an extended cylindrical structure, an extended conical structure, or an extended conical distal tip structure to maximize or enhance the suction force when a vacuum is applied at the proximal end of the suction chamber. In another example, the distal tip of the expandable support structure can be configured to expand from a cylindrical structure in a delivery structure to a substantially cylindrical structure after the expandable support structure is expanded to an expandable structure, wherein the extended structure is larger than the delivery structure, or wherein the extended structure is larger than the delivery structure in a range of 1.1 to 4 times, preferably 1.3 to 3 times. In yet another example, the distal tip of the expandable support structure is configured to expand from a cylindrical structure to an extended conical structure at the proximal segment of the distal tip, and is continuously connected to an extended cylindrical structure located distal to the extended conical structure. In still other configurations, the expanded configuration may be a combination of a long tapered proximal base (typically with at least a short tapered portion at the proximal end) and a distal cylindrical portion attached to the proximal end of the shaft.A number of specific configurations are shown in the figures.

[0041] In a specific example, the expandable support structure is configured to expand in response to the expansion of a balloon catheter within the expandable support structure. The balloon catheter can be configured to be delivered together with an aspiration catheter including an expandable support structure at the distal end, typically within the aspiration lumen of the aspiration catheter, wherein after the distal end of the distal tip of the aspiration catheter is positioned near the clot, the balloon catheter is expanded to expand the expandable support structure to the expanded structure, and then the balloon catheter is deflated and withdrawn from the aspiration catheter before applying a vacuum at the proximal end of the aspiration catheter to remove the clot. In another example, after the aspiration catheter is delivered to the clot and positioned near the clot, the balloon catheter is delivered to the distal end of the aspiration catheter, wherein the balloon catheter is advanced through the aspiration catheter until the balloon reaches the expandable distal tip segment or reaches the expandable distal tip, and then the balloon is expanded to expand the distal tip segment of the aspiration catheter, and then deflated and removed from the aspiration catheter, and a vacuum is applied at the proximal end of the aspiration catheter to remove (remove) the clot. In another example, the expansion catheter has an expandable member at the distal end of the catheter, the expandable member expands to expand an expandable distal tip including an expandable support structure (stent) and an expandable membrane, wherein the distal tip is incorporated into or coupled to the distal end of the suction catheter, wherein the expandable member includes a balloon, stent, cage or other expandable structure so that the expandable support structure is expanded from a delivery structure to an expanded structure. The expandable member can be a polymer material, a metal material or other material, wherein the member can be expanded from a delivery structure, a curled structure or a deflated structure to an expanded structure. Although the distal tip can be fully expanded along its entire length, depending on the patient's anatomical structure or other conditions, typically only a portion of the length of the distal tip can be expanded by a balloon or other expandable member. The portion of the distal tip expansion can be controlled by adjusting the length of the balloon present in the distal tip during expansion and / or selecting an expansion balloon with a different length.

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

[0043] The expanded shape of the support structure will generally be determined by the shape of the balloon or other expansion structure, that is, expansion of a cylindrical balloon within a plastically deformable support structure will cause the distal tip to assume a cylindrical shape, while expansion of a conical balloon will cause the distal tip to assume a conical shape.

[0044] In some less preferred examples, the expandable support structure can be configured to self-expand when released from a radial constraint. The radial constraint can be positioned on the expandable support structure. In other examples, the radial constraint can be positioned within the expandable support structure (lumen) and configured to release the expandable support structure in vivo to allow the expandable support structure to expand. In one example, the expandable support structure is formed of a shape memory material (such as NiTi nitinol or other shape memory material).

[0045] The support element can have one or more of a variety of shapes and attachment locations on the expandable structure. For example, the support element can extend to the radially expandable ring in the axial direction, extending toward the gap between adjacent rings, or extending into the gap between adjacent rings. In other examples, the support element can extend to the radially expandable ring in the circumferential direction, typically attached to the outwardly curved surface of the crown (peak), extending circumferentially into the adjacent gap. In other examples, the support element can extend to the radially expandable ring in the axial direction, enter the gap contained in the axial width of the ring or enter the gap defined by the axial width of the ring, or be contained in the space between each ring or the structural element of the ring or defined by the space, typically attached to the curved surface of the crown. In further other examples, at least some support elements may include any one or more of linear and / or nonlinear segments, and may have an extended tip (forming a contact pad discussed below) at the free end. In some examples, the support element can branch into two or more segments in the direction toward the free end. The support element can have the same or different lengths or widths. In some specific examples, the length of the support element can be equal to or less than the length of the adjacent pillars in the delivery structure. In other examples, the length of the support element can be equal to or less than the ring unit amplitude in the delivery configuration, or less than 1 times the ring unit amplitude in the delivery configuration. In yet another example, the length of the support element can be equal to or less than the length of the ring period in the delivery configuration. In other examples, the length of the support element can be greater than the ring unit amplitude only in the expanded configuration.

[0046] In some examples, the support element is attached to one or more of the axially inner crown region, the axially outer crown region, the struts, the intermediate struts, or to the axial or circumferential links.

[0047] In some preferred examples, at least some of the radially expandable rings include a serpentine, zigzag, box, diamond or other pattern including struts connected by crowns, and at least some of the adjacent rings are connected at one or more locations, such as by welding, bonding or fusing the crowns on the adjacent rings or by axial links or attachment points as patterned. Alternatively, at least some of the adjacent rings can be connected end-to-end in a spiral arrangement without axial links or attachment points, and preferably, the amplitude on at least some of the rings is fixed within each ring. In a preferred example, at least two adjacent rings or at least some of the adjacent rings at the distal tip of the expandable support structure have no more than two links or two attachment points connecting the at least two adjacent rings (or connecting the at least some of the adjacent rings). In another example, a plurality of circumferentially expandable rings are included, the plurality of circumferentially expandable rings comprising struts connected by crowns, wherein one or more adjacent rings are axially separated by gaps and are not connected, typically one or more adjacent unconnected rings are located at the distal end of the distal tip of the aspiration catheter, and are held together by an expandable membrane attached to one or more adjacent unconnected rings, thereby providing enhanced flexibility to the distal tip in the delivery structure and allowing one or more rings to expand from the delivery structure to the expansion structure. In a preferred example, the expandable support structure includes a plurality of adjacent expandable rings, wherein along the length of the expandable structure, the adjacent rings have two or fewer connectors or attachment points connecting the adjacent rings, preferably the adjacent rings have one connector or attachment point connecting the adjacent rings, wherein the length is the entire length of the expandable structure, or a segment along the axial length of the expandable structure, wherein the segment includes two or more rings. In another preferred example, the expandable support structure includes a plurality of adjacent rings, which are connected end-to-end in a spiral arrangement to enhance the flexibility of the aspiration catheter, thereby passing through tortuous anatomical structures in the delivery structure. Adjacent rings in this example are not connected by connecting rods or attachment points on adjacent rings, and at least some of the adjacent rings each have a fixed (or constant or the same) ring unit width, preferably, all of the at least some rings have a fixed (or constant or the same) ring unit width. In this example, at least some of the rings can be patterned as an open cell pattern, a closed cell pattern, or a combination of open and closed cell patterns along the length of the expandable stent.

[0048] Alternatively, in another example, at least some of the adjacent rings in the expandable support structure can be connected end-to-end in a spiral arrangement. This spiral arrangement typically will include a "smooth" spiral without additional curves or bends, i.e., a curve formed on a conical or cylindrical surface, which will become a straight line if the surface is unfolded into a plane. In other cases, one, two, three or more additional bends, curves or other secondary nonlinear portions can be superimposed on the spiral ring to enhance the bendability of the expandable structure, particularly in the curling or diameter reduction configuration during delivery. This one, two, three or more additional bends, curves or other secondary nonlinear portions can be formed by an expandable support structure or a non-expandable structure. In a specific preferred example, the expandable support structure forms a spiral coil.

[0049] In other preferred examples, the expandable membrane may include an elastic membrane or an inelastic membrane (stretchable membrane). The elastic membrane and / or the inelastic membrane may include one or more elastomers, polymer materials or other materials. In a preferred example, the expandable membrane is selected from 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 50A 15SPF, Elastollan S 60A 10W, Elastollan S 60A 10WH, Pellethane 2103-70A, Pellethane 70A, Pellethane2363-80A, 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 TPU60A, ResMart Ultra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMartUltra TPU 95A, Ecoflex00–30, Ecoflex 00–20, Ecoflex 5A, Dragon Skin 20, Pebax2533, Pebax3033, chronoprene, chronothane, chronosil, polyethylene (such as LDPE, HDPE, UltraHMWPE, etc.), Pebax (such as Pebax 2533, Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533、Pebax 7233, etc.), nylon (such as nylon 12, nylon 6 / 6 or nylon 6), polyurethane (such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMart Ultra TPU 72D), fluoropolymer (such as PTFE, poly (vinylidene fluoride-co-hexafluoropropylene), poly (vinylidene fluoride-co-hexafluoropropylene), fluorinated ethylene propylene, polychlorotrifluoroethylene, etc., or combinations thereof, or other elastomers, polymers or other materials.

[0050] In one example, the expandable membrane is formed of a polymer elastic membrane, which may be isotropic, but may be anisotropic in other cases, for example, the elastic membrane may be more elastic in the circumferential or radial direction than in the axial direction.

[0051] In some cases, the expandable film can be formed by heat shrinking on an expandable support structure (such as a stent) or heat shrinking to an expandable support structure (such as a stent). In other cases, the expandable film can be formed by laminating an expandable support structure (such as a support stent) between two or more layers of polymer materials (such as elastomeric materials, elastomers on the outer surface and non-elastic / stretchable polymer materials on the inner surface of the expandable structure, stretchable / non-elastic materials on the outer surface and inner surface of the expandable structure, or stretchable materials on the outer surface and elastic materials on the inner surface of the expandable structure). For example, two layers of elastomers, two layers of an elastic layer and a stretchable layer, or two layers of both stretchable layers can be mutually bonded (sandwiched) on an expandable support structure (such as a support stent) so that the two layers are sealed or bonded, and the two layers are sandwiched on the stent or other expandable structures, bonded and / or adhered to the stent or other expandable structures. In another example, the expandable film includes a polymer or other material that is configured to stretch and / or expand to an expanded structure from a delivery structure, wherein the material is configured to expand from the delivery structure to a larger structure that is 1.1 to 5 times the delivery structure. The expandable membrane is configured to have axial, radial and / or circumferential stiffness to allow radial flexibility while maintaining axial thrust transmission. 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 when the ring is expanded from the delivery configuration to the expanded configuration.

[0052] In a preferred example, the suction catheter comprises a tubular catheter body, which has a proximal end, a distal end and a suction chamber extending between the proximal end and the distal end. The suction catheter has an expandable distal tip, which has a central channel connected to the suction chamber of the tubular catheter body, and the expandable segment comprising an expandable support structure is attached to the expandable membrane or embedded in the expandable membrane. In a preferred example, the expandable support structure is patterned from a tube, a curved line or a rolled-up patterned sheet. The tube, the rolled-up sheet or the curved line in the preferred example are patterned as the expandable support structure, and the expandable support structure can be expanded from the delivery structure to the expanded structure. In some other preferred examples, the suction catheter comprises a tubular catheter body, which has a proximal end, a distal end and a suction chamber extending between the proximal end and the distal end. The suction catheter has an expandable distal tip, which has a central channel connected to the suction chamber of the tubular catheter body. The expandable support structure is attached to the expandable distal tip of the tubular catheter body or embedded in the expandable distal tip of the tubular catheter body. The tubular catheter body can be reinforced with a reinforcement structure on at least a portion of its length (near the expandable tip) by one or more of a coil, a stent, a stent with a support feature or other device. In some cases, at least a portion of the catheter body reinforcement structure includes one or more of a coil, a stent or a braid, which can be continuously formed with the expandable support stent or other expandable support structure of the expandable tip. In a preferred example, the reinforcement structure and the expandable stent or other expandable support structure are formed by a patterned tube. In other examples, the reinforcement structure and the expandable stent or other expandable support structure are formed by a curved line. In other cases, the reinforcement structure in the catheter body can be formed separately from the support stent of the expandable distal tip, then by welding, fusing, bonding or braiding the structure together, overlapping them at their interface on the length segment in one or more coupling or linking together.

[0053] In another example, the suction catheter comprises a tubular catheter body having a proximal end, a distal end and a suction chamber extending between the proximal end and the distal end. The suction catheter has an expandable distal end having a central channel connected to the suction chamber of the tubular catheter body, and the expandable distal end comprises an expandable support structure attached to or embedded in an expandable membrane. In a specific example, the range of the length of the expandable distal end including the expandable support structure is 0.5mm to 50cm, preferably 1cm to 25cm, and more preferably 2cm to 10cm. In yet another example, the length of the expandable distal end can substantially span the length of the suction catheter. In a specific example, the range of the length of the expandable distal end can be 50cm to 150cm. In a preferred example, the expandable distal end comprises an expandable distal tip, wherein the distal tip comprises a segment of an expandable support structure attached to or embedded in an expandable membrane. In some specific examples, the expandable distal tip segment comprises an expandable distal end segment. In some other examples, the expandable distal tip is identical to the expandable distal end.

[0054] In other preferred examples, the base ends of at least some of the plurality of support elements may each be attached to a strut. In other preferred embodiments, the base ends of at least some of the plurality of support elements may each be attached to an inner or outer curved surface of the crown. The support elements may extend or be oriented axially, circumferentially, or at other angles or directions relative to the support stent or other expandable support structure, support stent ring, or structural elements of the stent ring.

[0055] In a second aspect, the present invention provides a kind of suction catheter with alternative expandable support structure design.Alternative suction catheter comprises tubular catheter body, and this tubular catheter body has proximal end, distal end and the cavity extending between proximal end and distal end.Expandable support structure is attached at the distal end or distal tip of tubular catheter body or is incorporated into the distal end or distal tip of tubular catheter body, and has the central passage connected with the cavity of tubular catheter body, and expandable support structure comprises expandable membrane and expandable support or other expandable support structure, and this expandable support or other expandable support structure is configured to make expandable membrane radial expansion.Expandable membrane is typically elastically expandable, and expandable support or other expandable support structure is typically non-elastic expandable, that is, support is plastically deformed to expand shape and size and keeps expand shape and size in response to the radial expansion caused by balloon or other radial expansion tools.Like this, in the expansion structure, the expansion support structure " supports " membrane.

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

[0057] The expandable support structure may include a plurality of radially expandable rings arranged along a longitudinal axis, wherein at least some of the radially expandable rings include "expandable cells" having bends that can be plastically deformed to allow the rings to open radially. The cells may have an "open" configuration, such as U-shaped cells in a serpentine ring and V-shaped cells in a zigzag ring; square, rectangular or other regular or irregular polygons with one or more missing sides; and Alternatively, the unit may have a "closed" configuration, such as a diamond or box-shaped unit in a box-shaped ring, where the box shape may be rectangular, square, etc. or other regular or irregular polygonal shapes.

[0058] The support element can be located inside or outside the open cell. For example, the base of the cantilever support element can be attached to the inner curved surface of the crown and located in a U-shaped, V-shaped or Alternatively, the base of the cantilever support element can be attached to the outer curved surface of the crown and extend away from the support to enter the U-shaped, V-shaped or In the gaps near the open cells.

[0059] The support element may also be located inside or outside the box or other enclosed unit. For example, the base of the cantilevered support element may be attached to the inner surface of the box and protrude into the interior space of the box. Alternatively, the base of the cantilevered support element may be attached to the outside of the box or to a circumferential connecting rod that attaches the box or other enclosed unit together to form a ring.

[0060] Typically, at least one end of the support element is attached to at least one location on a strut or crown or ring in a radially expandable ring. However, in some cases, at least some of the support elements may not be attached to a support stent or other expandable support structure, but may be attached or coupled only to the expandable membrane so that they will reinforce the V-shaped, shaped, U-shaped or square / box-shaped space to enhance the resistance of the expandable membrane to collapse under vacuum / negative pressure when the distal tip is blocked or clogged by clot or other material.

[0061] In some cases, at least some of the support elements can extend in the circumferential direction from the radially expandable ring to the cell space (V-shaped, In a preferred example, at least some of the support elements extend circumferentially from the outer crown region to the adjacent outer crown region in one direction or in two opposite directions. In another preferred example, at least some of the support elements extend circumferentially from the struts to the adjacent struts in one direction or in two opposite directions. In other cases, at least some of the support elements extend in the axial direction from the radially expandable ring to the cell space (V-shaped, U-shaped or square / box-shaped space). In a preferred example, the support feature is configured to shorten when the expandable support structure is expanded to the expanded configuration, so that the support feature length is equal to or less than the amplitude of the expandable ring unit, or the support feature does not extend axially beyond the peak of the adjacent crown. In another preferred example, the support feature is configured to further expand or protrude when the expandable support structure is expanded to the expanded configuration, thereby providing enhanced support for the expandable membrane and providing enhanced collapse resistance to the expandable membrane when a vacuum is applied at the proximal end of the suction chamber.

[0062] In a preferred example, the present invention provides an aspiration catheter with an expandable support structure design. The aspiration catheter includes a tubular catheter body having a proximal end, a distal end, and a cavity extending between the proximal end and the distal end. The expandable support structure is attached to or incorporated into the distal end (or distal tip) of the tubular catheter body, and has a central channel connected to the cavity of the tubular catheter body, and the expandable support structure includes an expandable membrane and a support stent or other expandable support structure, which is configured to allow the expandable membrane to expand radially. The expandable support stent or other expandable support structure includes a plurality of radially expandable rings arranged along the longitudinal axis, wherein at least some of the radially expandable rings include a serpentine or zigzag or other open open pattern, the pattern including struts connected by crowns, forming a V-shape, shaped, U-shaped or open square / box shaped spaces. Multiple support elements are positioned in V-shaped, shaped, U-shaped or square space to support the V-shaped, shaped, U-shaped or open square / box-shaped space, and wherein when a vacuum is applied at the proximal end of the aspiration cavity and the distal tip is blocked or clogged with clot or other material, the support stent or other expandable support structure resists collapse of the membrane in the space in the expansion membrane and the stent or other expandable support structure structure, and wherein when the aspiration catheter is withdrawn into a guide catheter having a smaller inner lumen structure than the expanded structure of the support stent or other expandable support structure, the support stent or other expandable support structure is able to shrink from the expanded structure to the smaller structure.

[0063] In a preferred example, the present invention provides a suction catheter with an expandable support structure design. The suction catheter includes a tubular catheter body having a proximal end, a distal end, and a cavity extending between the proximal end and the distal end. The expandable support structure is attached to the distal end (or distal tip) of the tubular catheter body and has a central channel connected to the cavity of the tubular catheter body, and the expandable support structure includes an expandable membrane and a support bracket, which is configured to radially expand the expandable membrane. The expandable support bracket includes a plurality of radially expandable rings arranged along the longitudinal axis, wherein at least some of the radially expandable rings include a serpentine or zigzag or open pattern, which includes struts connected by crowns, and unit spaces are formed between the struts. Multiple support elements are positioned in the cell spaces to support the membrane in the cell spaces in a delivery configuration and / or an expanded configuration, and wherein the support elements resist collapse of the membrane in the spaces in the expanded membrane configuration when a vacuum is applied at the proximal end of the aspiration lumen and the distal tip is clogged or blocked by a clot or other material, and wherein 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 guide catheter having a smaller lumen configuration than the expanded configuration of the support structure.

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

[0065] In a preferred embodiment, the present invention provides a method for aspirating a clot from a patient's vascular system. The method includes positioning the distal tip of an expandable support structure of any described aspiration catheter in the patient's vascular system at or near the clot. The expandable support structure is typically expanded by balloon expansion but alternatively expands to an expanded configuration by self-expansion to engage the clot or a vessel wall near the clot. A vacuum is applied to the proximal end of a lumen in the catheter body to aspirate the clot into a central channel 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 before removal from the vascular system.

[0066] In a fourth aspect, the present invention provides a kind of suction catheter, it comprises a tubular catheter body with a proximal end, a distal end and a cavity extending along the longitudinal axis. The distal tip has a distal end that is incorporated into the tubular catheter body or is attached to the proximal end of the distal end of the tubular catheter body and a central channel (suction cavity) that is longitudinally connected with the cavity of the tubular catheter body. The distal tip is suitable for expanding from a delivery structure to a radially expanded structure or from a radially contracted structure to a radially expanded structure in response to a radially outward expansion force applied in the distal tip segment, and the distal tip comprises an expandable membrane and an expandable support structure (such as a stent), wherein the expandable stent or other expandable support structures comprise a plurality of rings spaced apart along the longitudinal axis, with gaps between the plurality of rings. At least some of the rings comprise forgeable metal or metal alloy, which is configured to plastically deform in response to a radially outward expansion force applied from the distal tip to expand the stent or other expandable support structures circumferentially.

[0067] In some cases, the expandable membrane is attached to the inner and / or outer surface of the expandable stent or other expandable support structure. In other cases, the expandable stent or other expandable support structure is embedded in or within the expandable membrane, wherein the expandable membrane includes at least two membranes, one membrane is attached to the outer surface of the expandable stent or other expandable support structure, and the other membrane is attached to the inner surface of the expandable stent or other expandable support structure. In other cases, the aspiration catheter includes an expandable tip, wherein the expandable tip includes an expandable membrane and an expandable support structure, such as a stent, wherein the expandable stent or other expandable support structure includes a plurality of rings spaced apart along a longitudinal axis, with gaps between the plurality of rings and within each ring, wherein the rings include structural elements, the structural elements including struts and crowns. An expandable stent or other expandable support structure is embedded in or within an expandable membrane, wherein the expandable membrane includes at least one membrane, wherein at least one membrane softens and / or melts on the outer surface of the expandable stent or other expandable support structure and / or on the inner surface of the expandable stent or other expandable support structure, thereby allowing the expandable membrane to protrude or flow into gaps existing within the ring structure elements and gaps existing between adjacent rings, adhere to the rings and ring structure elements, and provide a unified (integrated) expandable stent / membrane system that can be expanded from a collapsed or delivery configuration to an expanded larger configuration. In a preferred aspect, the expandable membrane covers the outer surface and / or the inner surface of the expandable structure, and also covers, wherein covering includes filling, flowing or protruding into one or more of at least some gaps existing within each ring of the expandable stent or other expandable support structure and gaps existing between adjacent rings of the expandable stent or other expandable support structure, wherein the flow membrane is sufficiently adhered to the stent or other expandable support structure ring structure elements to provide a unified system (integrated system) that can be expanded from a delivery configuration to an expanded configuration as an integrated system. The expandable membrane of the preferred aspect flows into the gaps existing between each ring, within each ring, the structural element comprises struts connected by a crown, wherein one or more expandable membranes of the preferred aspect cover the outer surface and / or inner surface of the expandable stent or other expandable support structure, cover at least some side surfaces of the expandable stent structural element, preferably cover substantially all side surfaces of the expandable stent structural element, and cover substantially all gaps between adjacent rings of the expandable stent or other expandable support structure. The expandable stent or other expandable support structure of the preferred aspect comprises an outer surface, an inner surface and two side surfaces. In other aspects, the expandable stent or other expandable support structure is formed by a curved line comprising an outer surface and an inner surface.

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

[0069] In some cases, the distal tip can 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 a preferred example, the enlarged conical configuration terminates at the distal end of the distal tip, thereby providing a maximum area (cross-sectional area) for clot retrieval.

[0070] In some cases, the tubular catheter body can 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 in the range of 0.25 mm to 25 mm.

[0071] In some cases, the distal tip may have a bending resistance 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 in its initial radially contracted configuration or delivery configuration as measured by a three-point flex test (described in more detail below). When a vacuum is attached to the proximal end and a clot (or embolism) engages and blocks the open distal end of the distal tip, the distal tip may also have a collapse pressure (vacuum) equal to or greater than 0.5 atm, preferably equal to or greater than 0.75 atm, more preferably about equal to 1 atm in its radially expanded configuration, and most preferably has a collapse pressure (vacuum) greater than 1 atm in its radially expanded configuration. In other examples, the distal tip 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 in its initial radially contracted configuration or delivery configuration.

[0072] Bending resistance is a measure of the flexibility of the distal tip through tortuous anatomical structures. Lower bending resistance indicates higher flexibility and better ability of the distal tip through tortuous anatomical structures. The bending resistance of the distal tip (or any other part of the suction catheter) can be measured by a three-point flexure test (ASTM F2606 standard guide for three-point bending of balloon expandable vascular stents and stent systems or equivalents). A portion of the catheter is placed vertically on two lower static supports, with a wedge between them. The spacing of the two supports is 13mm. While measuring the resistance, the middle part of the supporting catheter portion is displaced by reducing the wedge in the upper fixture of the Instron tensile tester (Instron, Norwood, Massachusetts, USA) at a deflection rate of 5.0mm / min. When the displacement reaches 2mm (about 15% of the span length), the test ends. The three-point bending resistance of this catheter portion is equal to the maximum deflection force measurement value during the test.

[0073] The collapse pressure is a vacuum or negative pressure that, when applied to the proximal end of the catheter body lumen, will cause the distal tip to at least partially collapse when the distal tip is completely blocked. "At least partially collapsed" refers to an irreversible contraction of more than 5%, more than 10%, or more than 15% of the distal tip lumen diameter or structure (contraction that does not subside after the application of vacuum is stopped). In a preferred example, the distal tip lumen diameter or structure comprising multiple expandable rings under an applied vacuum in an expanded (deployed) configuration is configured to resist collapse of the expandable rings in the expanded configuration when a vacuum is applied at the proximal end of the aspiration catheter and the distal tip is blocked or blocked by a clot or other material; or is configured to resist collapse by contracting no more than 5%, no more than 10%, or no more than 15% of any distal tip ring structure when the ring is under an applied vacuum in the expanded configuration and the tip engages with a clot (or embolism), or preferably by contracting no more than 10% of the expanded structure under vacuum, or most preferably by contracting no more than 5% of the expanded structure under vacuum. In another example, in an expanded deployed configuration, under a vacuum of approximately 1 atm, a distal tip lumen diameter or configuration comprising a plurality of expandable rings resists collapse by radially contracting no more than 5% of any of the expandable rings, wherein the radial contraction of no more than 5% is substantially reversible to the expanded configuration (i.e., the distal tip lumen diameter or configuration expands to a larger expanded configuration) when the vacuum or negative pressure applied at the proximal end of the catheter body lumen of the central channel having the distal tip is removed or ceased.

[0074] In another example, the present invention provides a kind of suction catheter, it comprises a tubular catheter body with a proximal end, a distal end and a cavity extending along the longitudinal axis. The distal tip has a proximal end attached to the distal end of the tubular catheter body and a central channel longitudinally connected to the cavity (suction cavity) of the tubular catheter body. The distal tip is suitable for expanding from a delivery structure to a radially expanded structure or from a radially contracted structure to a radially expanded structure in response to a radially outward expansion force applied in the distal tip, and the distal tip comprises an expandable membrane and an expandable support structure (such as a stent), wherein the expandable stent or other expandable support structures comprise a plurality of rings spaced apart along the longitudinal axis, with gaps between the plurality of rings. At least some of the rings comprise forgeable metal or metal alloy, which is configured to plastically deform in response to a radially outward expansion force applied from the distal tip to expand the stent or other expandable support structures circumferentially. In a preferred example, the expandable tip including an expandable membrane and an expandable stent or other expandable support structure is configured to radially contract no more than 15%, preferably no more than 10%, and more preferably no more than 5% of any expandable ring when a vacuum is applied to the proximal end of the aspiration lumen and the distal tip engages a clot (or embolism), and passively expands (without the need for an outward expansion force applied within the distal tip by the expandable member), wherein when the applied vacuum is stopped (or removed), the expanded configuration is greater than the contracted configuration, preferably wherein the expanded configuration is greater than the contracted configuration and is substantially the same as the expanded configuration prior to the application of any vacuum. In another example, under a vacuum of about 1 atm, the distal tip lumen diameter or configuration radially contracts no more than 15%, preferably no more than 10%, and more preferably no more than 5% in the expanded deployed configuration to resist collapse, wherein when the vacuum or negative pressure applied at the proximal end of the catheter body lumen having the central channel of the distal tip is removed or stopped, the radial contraction is substantially reversible (i.e., the distal tip lumen diameter or configuration expands to a larger configuration, greater than the contracted configuration under vacuum).

[0075] In another example, the present invention provides a suction catheter, which includes a tubular catheter body with a proximal end, a distal end and a suction chamber extending along the longitudinal axis. The distal tip has a proximal end attached to the distal end of the tubular catheter body and a central channel longitudinally connected to the suction chamber of the tubular catheter body. The distal tip is suitable for expanding from a delivery structure (or from a first removal structure) to a first radial expansion structure in response to a radially outward expansion force applied in the distal tip, wherein the range of the first radial expansion structure (second removal structure or removal structure) is 1.1 to 2 times that of the delivery structure, and wherein the distal tip includes one or more expandable membranes and an expandable stent, wherein the expandable stent includes a plurality of expandable rings spaced apart along the longitudinal axis, with gaps between the plurality of expandable rings, and wherein the expandable ring includes a structural element, which includes a strut connected by a crown. At least some of the rings include a forgeable metal or a metal alloy, which is configured to plastically deform in response to a radially outward expansion force applied from the distal tip, thereby expanding the stent or other expandable support structure circumferentially. An expandable tip including one or more expandable membranes and an expandable stent including a plurality of expandable rings are configured to radially contract to a first contracted structure, wherein the first contracted structure is smaller than the first expanded structure but larger than the delivery structure, preferably wherein when a vacuum is applied to the proximal end of the aspiration lumen, wherein the applied vacuum or when the applied vacuum ranges from 0.75 atm to about 1 atm, the first contracted structure is less than the first expanded structure by no more than 15%, preferably no more than 10%, and more preferably no more than 5% less than the first expanded structure, and wherein the expandable tip is configured to passively expand to a second expanded structure, wherein when the applied vacuum is removed or ceased, the second expanded structure is greater than the first contracted structure and equal to or less than the first expanded structure, wherein the expandable tip passively expands without the need for an outward expansion force to be applied within the distal tip by the one or more expandable membranes, and wherein the expandable tip is configured to contract to a second contracted structure, wherein when the distal tip is withdrawn into a guide catheter proximal to the distal tip in the patient's anatomy, the second contracted structure is less than the first contracted structure and equal to or larger than the delivery structure. In one example, the length of the expandable distal tip ranges from 0.5 mm to 500 mm, preferably ranges from 1 cm to 50 cm, and more preferably ranges from 1 cm to 25 cm. In one example, one or more expandable membranes of the expandable distal tip extend proximally beyond the proximal end of the distal tip of the suction catheter. In another example, one or more expandable membranes of the expandable distal tip have approximately the same length as the expandable stent, and both are incorporated into the distal end of the suction catheter or attached to the distal end of the suction catheter at its proximal end. In yet another example, one or more expandable membranes extend from the distal end of the distal tip to the proximal end of the suction catheter.

[0076] In some cases, the distal tip of an expandable stent or other expandable support structure has a minimum bending radius of 5 mm, preferably 3 mm, more preferably 2 mm without deformation and / or kinking in its delivery configuration or radially contracted configuration, and preferably, has a minimum bending radius of 10 mm, preferably 6 mm, more preferably 2 mm without deformation and / or kinking in its radially expanded configuration. The minimum bending radius can be determined by bending the distal tip around a cylinder of known radius and observing whether the distal tip deforms and / or kinks.

[0077] In some cases, the ring of the expandable stent or other expandable support structure spans a length measured in the longitudinal direction 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 example, the present invention provides a kind of suction catheter, it comprises a tubular catheter body with a proximal end, a distal end and a suction chamber extending along the longitudinal axis. The distal tip has a proximal end of the distal end of the tubular catheter body and a central channel longitudinally connected to the suction chamber of the tubular catheter body. The distal tip is suitable for expanding from a delivery structure to a first radial expansion structure in response to a radial outward expansion force applied to the distal tip, wherein the range of the first radial expansion structure is 1.1 to 2 times of the delivery structure, and wherein the distal tip comprises one or more expandable membranes and an expandable stent, wherein the expandable stent comprises one or more expandable rings spaced apart along the longitudinal axis, with a gap between these expandable rings, and wherein the expandable ring comprises a structural element, and the structural element comprises a pillar connected by a crown. One or more rings are made of forgeable metal or metal alloy (or alternatively formed by a shape memory metal alloy), which is configured to plastically deform in response to a radial outward expansion force applied from the distal end or the distal tip to expand the stent or other expandable support structure circumferentially. In a specific example, the expandable stent is composed of one, two or three expandable rings. In another specific example, the expandable stent is comprised of an expandable ring.

[0079] In some cases, the distal tip of the expandable stent or other expandable support structure has a minimum bending radius of 5 mm, preferably 3 mm, more preferably 2 mm without deformation and / or kinking in its delivery configuration or radially contracted configuration, and preferably has a minimum bending radius of 10 mm, preferably 6 mm, more preferably 2 mm without deformation and / or kinking in its radially expanded configuration. The minimum bending radius can be determined by bending the distal tip around a cylinder of known radius and observing whether the distal tip is deformed and / or kinked.

[0080] In some cases, the ring of the expandable stent or other expandable support structure spans a length measured in the longitudinal direction 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 stent or other expandable support structure consists of 1 ring to 800 rings or more, preferably 25 rings to 650 rings or more, more preferably 50 rings to 500 rings or more, spanning one or more expandable axial segment lengths ranging from 0.2 mm to 50 cm, preferably 10 mm to 40 cm, and more preferably 15 mm to 25 cm, arranged in the longitudinal direction from the distal end to the distal or proximal end of the distal tip of the aspiration catheter. In a preferred example, the expandable stent or other expandable support structure includes a plurality of rings per mm of axial (longitudinal) stent or other expandable support structure length or consists of a plurality of rings per mm of axial (longitudinal) stent or other expandable support structure length, ranging from 2 rings to 5 rings per mm of axial (longitudinal) stent length, preferably 2.5 rings to 4 rings per mm of axial (longitudinal) stent length, and more preferably 3 rings to 4 rings per mm of axial (longitudinal) stent length.

[0082] In some cases or in some examples, the expandable support structure includes a plurality of adjacent rings with gaps therebetween. In some examples, the gaps between adjacent rings have a length measured in the longitudinal / axial direction ranging from 0.0125 mm to 0.25 mm, preferably 0.025 mm to 0.2 mm, and more preferably 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 in the axial direction) can be constant. In other cases, the axial length of the gap between adjacent rings can be variable. For example, the length (or axial length) of the gap between at least some adjacent rings ranges from 0.05 mm to 0.2 mm. In another preferred example, a plurality of adjacent rings span at least a 3 mm segment along the length of the expandable structure, more preferably span at least a 7 mm segment along the length of the expandable stent, and more preferably span at least a 20 mm segment along the length of the expandable stent, wherein the gap length between adjacent rings 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 axial length, typically 1.5 to 5 rings per mm of axial length, and more typically 2 to 5 rings per mm of axial length, or more typically 3 to 4 rings per mm of axial length.

[0085] In some preferred cases, at least some of the adjacent rings are connected continuously end-to-end in a spiral arrangement. In other cases, at least some of the adjacent rings are planar, arranged in parallel, and connected by axial connecting rods or other devices (such as attachment points), and are not connected end-to-end. Parallel planes can be vertical or tilted relative to the longitudinal axis of the distal tip in its delivery structure. Adjacent rings can preferably be connected by a single axial connecting rod or attachment point, or by no more than two axial connecting rods or two attachment points. In some preferred cases, at least some of the adjacent rings of the expandable stent are connected continuously end-to-end in a spiral pattern or arrangement. In other cases, at least some of the adjacent rings of the expandable stent are planar, arranged in parallel, and connected by axial connecting rods or attachment points that connect or connect the structural elements on the adjacent rings. In this other case, the adjacent rings of the stent are not connected continuously end-to-end in a spiral arrangement. Parallel planes can be vertical or tilted relative to the longitudinal axis of the distal tip in its delivery structure. Adjacent rings may preferably be connected 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 stent are planar, arranged in parallel and are not connected to each other. (Not connected by connecting rods, attachment points, or connected end-to-end with a spiral arrangement). The parallel planes can be vertical or tilted relative to the longitudinal axis of the distal tip in its delivery structure. In this case, at least some adjacent rings are covered by one or more films, and the one or more films adhere to the unconnected adjacent rings, keep them together, and allow at least some adjacent rings to expand to the expanded structure from the delivery structure. This allows the delivery capability of the distal tip to be enhanced to pass through the vascular anatomy in the delivery structure, and allows at least some rings to expand to the expanded structure from the delivery structure, and when vacuum is applied at the proximal end of the suction chamber and the distal end of the distal tip is engaged by clots (or embolic blockages), the distal tip is resisted from collapsing in the expanded structure.

[0087] In some cases, at least some of the adjacent loops in the helical and / or planar arrangements can include nonlinear portions.

[0088] In some cases, all adjacent rings in a spiral and / or planar arrangement have no non-linear portions.

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

[0090] In some cases, the wrought metal includes a metal or metal alloy selected from the group consisting of: cobalt chromium, such as L-605, MP35N, Stellite 6B, ASTM F1537 / F799 Alloy 1, ASTM F1537 / F799 alloy 2; stainless steels such as 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L and 420S; tantalum; niobium; tungsten; molybdenum; molybdenum; molybdenum alloys such as molybdenum-rhenium, wherein the sum of molybdenum and rhenium is 90% to 100%, and molybdenum-rhenium may include one or more metals such as 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; platinum; platinum alloys such as platinum-iridium, platinum-chromium, platinum-cobalt-chromium; magnesium; magnesium alloys such as Mg-3A1-1Z, Mg-Zn-Se and Mg-Zn-Cu; zinc, etc. or others.

[0091] In some cases, the stent or other expandable support structure comprises a metal or metal alloy selected from nitinol, superelastic nitinol, etc. or others. In this case, the expandable support structure is constrained in the delivery configuration and released from the constraint to expand the stent to the expanded configuration.

[0092] In some cases, the expandable membrane includes one or more elastic membranes, and / or a non-elastic but stretchable membrane, and / or one or more plastically deformable membranes, wherein the membrane may include one or more membranes including polymers, elastomers, or other materials 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 be more elastic in the circumferential direction than in the axial direction.

[0094] In some cases, the expandable membrane may include an elastic membrane, a non-elastic but stretchable membrane, or other types of expandable materials. Examples of suitable materials are listed above.

[0095] In some cases, the inelastic membrane can be configured to stretch or plastically deform as the stent or other expandable support structure expands. In other cases, the inelastic membrane can be configured to expand as the stent or other expandable support structure expands.

[0096] In some cases, the distal tip can be formed by heat shrinking the tubular film on the expandable stent or other expandable support structure. In other cases, the distal tip can be formed by laminating the expandable stent or other expandable support structure between the layers of the tubular film. For example, the layers can be bonded to each other so that there is a seal between the layers. In a preferred example, one or more expandable membranes flow and cover at least some side surfaces of the structural elements of the expandable support structure, fully adhere to the structural elements to provide a unified system (integrated system) in the delivery structure and when expanded to the expansion structure. In another example, the polymer layers on the outer surface of the stent and the inner surface of the stent can be bonded to each other and / or adhere to the stent structural elements so that there is a seal between the layers, and / or adhere to the structural elements to provide a unified integrated system that can be expanded from the delivery structure to the expansion structure. In a preferred example, the structural elements of the stent cannot be freely moved or expanded without moving or expanding the expandable membrane adjacent to the structural elements. In another example, the layers on the outer surface of the stent and the inner surface of the stent can be bonded to each other so that there is a seal between the layers. In yet another example, the layers on the outer surface of the stent and the inner surface of the stent can be coupled, attached and / or adhered to each other, thereby substantially eliminating gaps between structural elements of the stent (or filling the gaps) and providing a unified expandable stent that can be expanded from a delivery configuration to an expanded configuration. In yet another example, one or more layers on the outer surface of the stent or one or more layers on the inner surface of the stent are melted or laminated to the structural elements of the stent, thereby at least partially eliminating gaps between the structural elements and adhering to the structural elements, thereby providing the stent with the ability to expand from a delivery configuration to an expanded configuration as a unified system.

[0097] In some cases, the tubular membrane can be composed of at least two membrane segments, wherein the at least two membrane segments can include a single type of material, at least two types of materials, or three or more different types of materials.

[0098] In some cases, at least two film segments can cover at least one outer surface of an expandable stent or other expandable support structure. In some cases, at least two film segments can cover at least one inner surface of an expandable stent or other expandable support structure. In some cases, at least two film segments cover both the inner and outer surfaces of an expandable stent or other expandable support structure, wherein at least one of the at least two film segments covers the outer surface of the stent and at least a second film segment covers the inner surface of the expandable stent.

[0099] In some cases, the tubular catheter body can be reinforced by a catheter stent or other support structure (typically a flexible but non-expandable support structure) over at least a portion of its length. In a specific example, the catheter stent or other support structure can be formed continuously with an expandable stent or other expandable support structure. For example, the catheter and the support stent can be patterned from the same tube or curved line. In other cases, the catheter stent and the expandable stent can be formed by one or more curved lines, each of which spans at least a portion of a typically non-expandable catheter stent and an expandable distal tip stent.

[0100] In some cases, the expandable stent may also include a plurality of cantilevered support elements or other support elements, each support element having a base end and a free end, wherein the base end is attached to one of the radially expandable rings and the free end extends toward or into an adjacent axial and / or circumferential gap.

[0101] In some cases, at least some of the multiple rings can include struts connected by a bend (crown), and the base ends of at least some of the multiple support elements are attached to the struts, and the base ends of at least some of the multiple support elements are attached to the bend (crown).

[0102] In some cases, the base ends of at least some of the plurality of support elements can be attached to the inner surface of the ring, ie, the inner curvature of the crown.

[0103] In some cases, the base ends of at least some of the plurality of support elements can be attached to the outer surface of the ring (ie, the outer surface of the crown) or the apex of the outer surface of the crown.

[0104] In some cases, at least some of the plurality of support elements have a constant width over a distal portion thereof. In some cases, at least some of the plurality of support elements have a constant width over an entire length thereof.

[0105] In some cases, at least some of the plurality of support elements have a variable width at a distal portion thereof.

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

[0107] In some cases, at least some of the plurality of support elements have distal tips that terminate flush with the bend of the connecting struts.

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

[0109] In a fifth aspect, the invention provides a kind of suction catheter, it comprises the tubular catheter body with proximal end, distal end and the cavity extending along longitudinal axis.The distal end comprises expandable distal tip and central channel, and wherein central channel is typically connected with the cavity of tubular catheter body longitudinally.The distal tip is suitable for expanding to radially expanded structure from radial contraction or delivery structure in response to the radially outward expansion force applied inside the distal tip, and the distal tip comprises the tubular membrane covering expandable stent or expandable support stent (for example, adhere to expandable stent or expandable support stent, be attached to expandable stent or expandable support stent, be bonded to expandable stent or expandable support stent or use expandable stent or expandable support stent lamination). The expandable stent or expandable support stent includes a plurality of rings spaced apart along the longitudinal axis, with gaps (extending between the rings) between the plurality of rings, and at least some of the rings include circumferentially adjacent units having a bend (such as a crown) that is configured to straighten (such as expansion) in response to a radially outward expansion force applied inside the distal tip to allow the ring to expand from a radially contracted or delivered structure to a radially expanded structure, wherein the radially expanded structure is greater than the contracted structure. In some preferred cases, at least some adjacent rings of the expandable stent or expandable support stent are continuously connected end-to-end in a spiral arrangement, typically without an axial connecting rod or attachment point. In a preferred case, at least some adjacent rings of the expandable stent or expandable support stent have a fixed unit amplitude in each ring. In other cases, at least some adjacent rings of the expandable stent or expandable support stent have a fixed unit amplitude in at least some rings. In rare cases, at least some adjacent rings of the expandable stent or expandable support stent may have a variable unit amplitude in each ring or in at least some rings. In this case, at least some adjacent rings are in the range of 70 ° to 89.9 ° or 75 ° to 89.90 in the patterned or delivery structure relative to the pitch angle of the longitudinal axis of the stent or distal tip, typically 80 ° to 89.9 °, more typically 84 ° to 89.75 °, and often 85 ° to 88.5 °. As used herein and as shown in the figure, "pitch angle" will be an acute angle (between 0 ° and 90 °) formed by the ring relative to the longitudinal axis of the distal tip of the suction catheter, rather than an obtuse angle (between 90 ° and 180 °). In some other cases, at least some adjacent rings of the expandable stent or expandable support stent are planar, arranged in parallel, and are connected by an axial connecting rod or attachment point connecting the structural elements on the adjacent rings. In rare cases, at least some adjacent rings are connected by no more than two axial connecting rods, no more than two attachment points connecting the structural elements on the adjacent rings, or no more than one connecting rod and no more than one attachment point. The parallel planes may be perpendicular or oblique relative to the longitudinal axis of the distal tip in its delivery configuration.

[0110] In some cases, the cells can be arranged in any one or more of a box pattern, a diamond pattern, a sinusoidal pattern, a serpentine pattern, an omega wave pattern, a sawtooth pattern, a square wave pattern, a rectangular wave pattern, a wavy pattern, a groove pattern, an open cell pattern, a closed cell pattern, a combination of open and closed cell patterns, a combination of patterns, or other patterns, etc.

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

[0112] In some cases, a unit may include struts connected by bends.

[0113] In some cases, in the delivery configuration or in the patterned configuration, at least some of the expandable cells on one or more rings of an expandable stent, or at least some of the expandable cells on at least some of the rings of an expandable stent, or at least some of the expandable cells on each ring of an expandable stent, or at least some of the circumferentially adjacent cells of at least some of the rings of an expandable stent, or at least some of the circumferentially adjacent cells of at least some of the adjacent rings of an expandable stent, or substantially all of the cells on an expandable stent, or all of the cells along the length of the stent (where the length is less than the length of the stent), or all of the cells along the length of the stent may have a cell period (the distance between similar points on circumferentially adjacent cells measured in the collapsed configuration) ranging from 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 enhances the circularity of the ring, the circularity of the plurality of rings, or the circularity of the expandable stent, thereby enhancing the passage of the expandable stent in the vasculature without deformation or kinking in the delivery configuration, and the enhanced circularity resists collapse of the expandable distal tip when a vacuum is applied at the proximal end of the aspiration catheter while the distal tip is engaged with (or blocked by) a clot when expanded to the expanded configuration. In addition, having a small cell period increases (or enhances) the aspiration area within the ring, within the plurality of rings, or within the expandable stent or the expandable distal tip.

[0114] In some cases, in a delivery configuration or a patterned configuration, circumferentially adjacent cells on at least one ring or at least some rings of an expandable stent (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, at least some rings, or all rings of an expandable stent may have a peak-to-peak amplitude (ring width in the longitudinal / axial direction (axial width of the ring)) ranging from 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 example, the cell amplitude of each unit on the same ring has the same length (i.e., fixed or constant) in the delivery configuration or the patterned configuration. In another preferred example, at least some adjacent rings have cell or ring amplitudes of the same length on the at least some rings. Having a small amplitude enhances the flexibility of the expandable stent, thereby enhancing the penetration of the expandable stent (or expandable distal tip) when the suction catheter is advanced into the vascular system. Additionally, having a small amplitude further enhances the expandable stent in the expanded configuration and resists collapse of the stent or an expandable membrane coupled to the stent when a vacuum is applied at the proximal end of the aspiration catheter and the distal tip engages a clot.

[0115] In some cases, circumferentially adjacent cells (or at least some circumferentially adjacent cells, or at least some circumferentially adjacent cells on at least some adjacent rings, or all cells on an expandable stent, or at least some cells within a ring, or all cells within at least some rings, or all cells within a ring of an expandable stent) can have the following range of cell period to (peak-to-peak axial width of the ring) amplitude ratios measured for all examples in a delivery configuration or patterned configuration: in one example, the cell period to (peak-to-peak axial width of the ring) amplitude ratio ranges from 0.3:1 to 1.6:1; in other examples ... The range of the amplitude ratio of period to (peak-to-peak axial width of the ring) is 0.4:1 to 1.5:1; in another example, the range of the amplitude ratio of unit period to (peak-to-peak axial width of the ring) is 0.5:1 to 1.3:1; in another example, the range of the amplitude ratio of unit period to (peak-to-peak axial width of the ring) is 0.6:1 to 1.2:1; in another example, the range of the amplitude ratio of unit period to (peak-to-peak axial width of the ring) is 1:1 to 1.6:1; in another example, the range of the amplitude ratio of unit period to (peak-to-peak axial width of the ring) is 0.3:1 to 1.2:1. In some other examples, circumferentially adjacent cells (or at least some cells on one ring or multiple rings or at least some rings, or all cells on at least one ring or at least some rings or at least some rings of the expandable stent) can have a cell period and (peak-to-peak axial width of the ring) amplitude measured in the delivery configuration (or measured in the patterned configuration) that each has a length of 0.25 mm ± 0.2 mm, preferably each has a length of 0.25 mm ± 0.15 mm, and more preferably each has a length of 0.25 mm ± 0.1 mm. Having the lengths of at least some cell periods and amplitudes within one ring or multiple rings or at least some rings within ± 0.2 mm of each other enhances the symmetry and / or compactness of the rings of the expandable stent against deformation and / or kinking when the expandable stent is passed through the vasculature in the delivery configuration.

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

[0117] In some cases, at least some of the rings in a stent or other expandable support structure can have a ratio of (1) the number of bends to (2) the circumference, wherein the ratio is typically in the range of 0.8 per mm to 15 per mm, preferably in the range of 1 per mm to 15 per mm, more preferably in the range of 2 per mm to 15 per mm, more preferably in the range of 3 per mm to 15 per mm, and most preferably in the range of 4 per mm to 12 per mm. Support structures having cantilevered support elements 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 can be constant or variable over at least some of the rings, over all or a portion of the stent or other expandable support structure.

[0119] In some cases, the loop may span a segment of the distal tip where the segment has a length measured in the longitudinal direction ranging from 0.5 mm to 500 mm or more, typically 10 mm to 100 mm, more typically 10 mm to 40 mm.

[0120] In some cases, the ring can span a segment of the distal tip having a length measured in the longitudinal direction in the range of 0.5 mm to 500 mm or more, typically 10 mm to 100 mm, more typically 10 mm to 40 mm. In some cases, the stent is comprised of an expandable ring spanning a length in the distal tip measured in the longitudinal direction in the range of 0.1 mm to 0.5 mm, typically 0.15 mm to 0.35 mm, more typically 0.15 mm to 0.3 mm.

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

[0122] In a preferred example, the ring of the expandable support structure includes a bend (e.g., a crown) and struts, wherein the bend has a length measurement along its arc and the struts have an axial length, wherein the ratio of the arc length of the bend or crown to the axial length of the struts ranges from 0.2:1 to 2:1, preferably from 0.5:1 to 1.5:1, and more preferably from 0.75:1 to 1.25:1. In a specific preferred example, the arc length of the crown and the axial length of the struts connected to the crown are both in the range of 0.05 mm to 0.25 mm, preferably from 0.075 mm to 0.225 mm, and more preferably from 0.1 mm to 0.2 mm, preferably about 0.15 mm, or preferably 0.15±0.05 mm, for example 0.15±0.05 mm.

[0123] In some cases, at least some of the adjacent rings in the expandable distal tip can be formed by a tube or a curved line, and are continuously connected end-to-end with a spiral arrangement. For example, at least some adjacent rings can be connected with an absolute pitch angle relative to the longitudinal axis, and the range of the absolute pitch angle is 70 ° to 89.9 °, or 75 ° to 89.9 °, typically 80 ° to 89.9 °, more typically 84 ° to 89.75 °, and often 85 ° to 88.5 ° (as in patterned or delivery structures). The absolute pitch angle can be constant or variable along at least some rings or along the length of the expandable support (or along the length of the expandable support, wherein the length is shorter than the length of the support, or along other expandable support structures) or other expandable support structures. The absolute pitch angle of at least some adjacent rings can be constant or variable along the length of the expandable support or other expandable support structures. The pitch angle is typically measured in a patterned structure. Alternatively, the above-mentioned pitch angle can be measured in a delivery structure. In a preferred case, at least some adjacent rings do not have a connecting rod or attachment point between adjacent rings. In other preferred cases, at least some of the adjacent rings have a fixed cell amplitude within each ring or within at least adjacent rings. In rare cases, at least some of the adjacent rings may have attachment points or connecting rods connecting adjacent rings. In other rare cases, at least some of the adjacent rings may have a variable cell amplitude or a variable ring amplitude 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 connected by axial connecting rods or by other means, such as crowns on adjacent rings that are fused / welded or otherwise connected together (attachment points). The separate parallel planes may be oriented vertically or at an angle relative to the longitudinal axis of the stent or other expandable support structure when straightened. In some cases, the separate adjacent rings are not connected together by connecting rods 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 include a wrought metal or metal alloy configured to be plastically deformed. The wrought metal may include the metals or metal alloys previously described in this application.

[0126] In some cases, the radially contracted structure of the stent or other expandable support structure and / or the distal tip can 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 structure can 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 can be configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to a radially outward expansion force applied within the distal tip.

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

[0129] In some cases, circumferentially adjacent cells of at least some of the rings in the distal tip may have circular, elliptical, rectangular, flat, or substantially flat outer and / or inner surfaces that define "facets" in a polygonal structure. In those cases, the ring may have 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, wherein in the expanded configuration, the length of the first radius is 97% to 99.9%, preferably 98% to 99.7%, more preferably 98.5% to 99.5%, and most preferably 99% to 99.5% of the length of the second radius. This provides the expandable distal tip with one or more of: an enlarged lumen configuration (or maximum lumen configuration), enhanced aspiration lumen area, maximized aspiration lumen area in the expanded configuration, resistance to collapse in the expanded configuration under vacuum when the distal tip engages a clot (or becomes blocked or occluded by a clot or other material), enhanced delivery capabilities of the aspiration catheter distal tip, and enhanced resistance to deformation or kinking of the expandable distal tip in the delivery configuration when traversing the vasculature. Preferably, the expandable tip in the expanded configuration has a "roundness" in the range of 97% to 99.9%, preferably in the range of 98% to 99.5%, and more preferably in the range of 98.5% to 99.5% (as described below with reference to Fig.16 In another preferred embodiment, the roundness of the expandable tip in the expanded configuration is greater than 97%, preferably greater than 98%, more preferably greater than 98.5%, and most preferably greater than 90%. The roundness of the expandable distal tip refers to the lumen configuration. Alternatively, the roundness of the expandable distal tip measures the outer circumference of the distal tip.

[0130] In some cases, the tubular catheter body can have a length ranging from 50cm to 200cm from the proximal end to the distal end, the tubular catheter body can have an outer diameter ranging from 0.5mm to 30mm, and the tubular catheter body can have an inner cavity diameter ranging from 0.25mm to 25mm. In one example, the length range of the distal tip can be expanded to 0.5mm to 50cm. In another example, the length of the distal tip can be expanded to be the same as the distal length. In other examples, the distal tip can be expanded to substantially include the entire length of the catheter tubular body. In yet another example, the distal tip can be expanded to be composed of an expandable stent (or an expandable support stent), which is covered with one or more polymer materials or embedded in one or more polymer materials, wherein the expandable stent includes a circumferential ring, the ring includes a plurality of pillars connected by a crown, and wherein the ring can be expanded from a delivery structure to an expanded structure, when a vacuum is applied at the proximal end of the suction chamber and the distal end of the distal tip is opposite to or blocked by a clot, the ring resists collapse. In some other cases, the expandable stent includes 2, 3, 4 or 5 circumferential rings.

[0131] In some cases, the expandable distal tip may also include a plurality of support elements, wherein each support element may have a base end and a free end, and wherein the base end is attached to one of the radially expandable rings and the free end extends toward or into an adjacent gap in an axial and / or circumferential direction toward the distal tip. For example, at least some of the plurality of rings may include struts connected by a bend, and the base ends of at least some of the plurality of support elements may be attached to the struts and / or the base ends of at least some of the plurality of support elements may be attached to the bend.

[0132] In other cases, the base ends of at least some of the plurality of support elements may be attached to an inner surface of the ring (or a structural element of the ring) and / or 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 on their distal portions or along their entire length. In other cases, at least some of the multiple support elements may have a variable width on 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 base and a constant width along the remaining length of the support element. In a preferred example, the width of the support element is greater than the width of an adjacent strut, crown, or ring segment. Having a larger support element width than adjacent structural elements allows an expandable stent or other expandable support structure to shrink after the stent is expanded to the expanded configuration when the stent is withdrawn into a guide catheter having a smaller lumen than the expanded configuration of the expandable stent.

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

[0135] In some cases, at least some of the plurality of support elements can have distal tips that terminate flush with an adjacent bend or crown of a connecting strut.

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

[0137] Still in other aspects, the present invention provides a method for aspirating clots from a patient's vascular system, the method comprising positioning the distal tip of any one of the aspiration catheters described herein in the patient's vascular system at the clot region. The distal tip is expanded to its radially expanded structure, or expanded to a radially expanded structure from a delivery structure to engage the vessel wall near the clot region, or to engage the clot, and negative pressure is applied to the proximal end of the cavity in the catheter body to aspirate the clot into the central channel of the expanded expandable support structure (suction cavity). Under the same applied vacuum, the expanded structure has a greater suction force than the delivery structure. The suction force in the expanded structure is 1.1 to 10 times greater than the suction force of the delivery structure, preferably 1.5 to 6 times greater, and more preferably 1.8 to 6 times greater.

[0138] In some cases, at least a portion of an expandable stent or other expandable support structure remains at least partially unexpanded after another portion of the expandable stent is expanded. The at least partially unexpanded portion can have a variety of shapes, such as conical, oval, rectangular, flat, or other shapes. In some other cases, at least one segment of an expandable stent or other expandable support structure remains unexpanded after another adjacent segment of the expandable stent or other expandable support structure is expanded to an expanded configuration.

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

[0140] In some cases, a segment or other portion of an expandable stent or other expandable support structure remains at least partially unexpanded after another portion of the expandable stent is expanded.

[0141] In other aspects, the present invention provides an aspiration catheter comprising a tubular catheter body having a proximal end, a distal end, and a cavity extending along a longitudinal axis. An expandable coil comprising continuous helical turns is arranged along the longitudinal axis, wherein the expandable coil comprises a wavy bend and a strut, and there are gaps between the continuous turns, wherein the continuous turns are inclined at an acute pitch angle relative to the longitudinal axis. The sheath is arranged around the expandable coil. In a preferred example, in a patterned or delivery configuration, the acute pitch angle ranges from 70° to 89.9°, typically 80° to 89.75°, and more typically 82° to 89.75° relative to the longitudinal axis. In a preferred example, at least some of the continuous turns do not have a connecting rod or attachment point connecting the adjacent turns. In another preferred example, at least some of the adjacent turns have a fixed unit amplitude within each turn or within at least some of the adjacent turns.

[0142] In some cases, an expandable stent or other expandable support structure is comprised of an expandable coil, wherein the expandable coil comprises a plurality of adjacent expandable rings continuously connected end to end in a spiral arrangement, wherein each ring comprises a structural element comprising struts connected by a crown, and wherein the expandable coil has an acute pitch angle in a range of 70° to 89.9°, preferably in a range of 80° to 89°, relative to the longitudinal axis in a patterned or delivery configuration. The expandable coil is expanded from a delivery configuration or a collapsed configuration to an expanded configuration by an expandable support structure (such as a balloon catheter) that is radially expanded inside the expandable coil, wherein the expandable coil is referred to as balloon-expandable.

[0143] In some cases, the expandable coil can be configured to expand via an expandable support structure that expands radially within the interior of the expandable coil. For example, the expandable coil can be balloon expandable.

[0144] In some cases, the coil may be at least partially formed from a wrought metal or metal alloy. In some other examples, the coil may be formed from a wrought metal or metal alloy.

[0145] In some other cases, the coil can be formed of a shape memory metal or shape memory alloy, wherein the expandable distal tip is constrained in a delivery configuration and released to expand to a larger expanded configuration. Examples of shape memory alloys include Nitinol or others.

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

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

[0148] In some cases, the expandable coil can be attached to a reinforcement member in the proximal section of the catheter body.

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

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

[0151] In some cases, the expandable coil can be attached to, incorporated into, or coupled to the distal end of the tubular catheter body. In some other cases, the expandable coil can extend from the distal end to the proximal end of the tubular catheter body, or to the proximal end of the tubular catheter body. In some cases, the expandable coil can be attached to the proximal end of the tubular catheter body.

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

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

[0154] In some cases, the maximum outer diameter of the coiled delivery configuration of the expandable coil ranges from 0.5 mm to 30 mm, and the maximum outer diameter of the expanded deployed configuration ranges from 1.5 mm to 40 mm.

[0155] It should be understood that all features and aspects of the apparatus and method of the present invention described herein can be arranged in different combinations, and even if no specific embodiment or example of a specific combination is provided, these features and aspects are covered by the claims. Features described in whole or in part in all paragraphs, examples, embodiments, drawings and other aspects set forth herein can be combined in a manner not specifically described and can be part of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0156] Figure 1 A first system constructed in accordance with the principles of the present invention is shown, the first system comprising (1) an aspiration catheter having an expandable distal tip and (2) a distal tip expansion catheter.

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

[0158] Figure 1A-1 Is Figure 1A Detailed view of the area defined by boundary line 1A-1 to 1A-1.

[0159] Figure 1A-2 Is Figure 1A Detailed view of the area defined by boundary line 1A-2 to 1A-2.

[0160] Figure 1B Shows Figure 1A A system is introduced via the femoral artery into a target location in the cerebral vasculature.

[0161] Figure 2A is shown in a non-expanded configuration (or in a delivery configuration) Figure 1 A detailed view of an example of an expandable distal tip of an aspiration catheter of a system of the invention, wherein a portion of a covering (or laminating) film is removed or detached to expose an expandable support stent or other expandable support structure. As shown, the reinforcement coil is continuously connected to the proximal end of the expandable support stent or other expandable support structure and is formed to be continuously connected to the proximal end of the expandable support stent. Figure 2A The expandable distal tip configuration and the non-expandable proximal segment (reinforced coil) configuration in this example have the same delivery configuration (or have the same outer diameter profile).

[0162] Figure 2B yes Figure 1 An "expanded" view of an example of an expandable support stent or other expandable support structure at the expandable distal tip of an aspiration catheter of a system of the invention. A reinforcement structure formed continuously with the proximal end of the expandable support structure is shown.

[0163] Figure 2C yes Figure 1 Detailed view of an adjacent pair of circumferentially expandable support rings at the expandable distal tip of an aspiration catheter of a system of FIG. 1 , showing support elements within most (but not all) cells and connecting rods connecting adjacent rings.

[0164] FIG. 3A to FIG. 3D An alternative expandable configuration is shown. FIG. 2A to FIG. 2C An example of a support stent or other expandable support structure at an expandable distal tip of an aspiration catheter.

[0165] Figure 3E The same as shown in a non-expanded configuration (or delivery configuration) having a reduced tip configuration relative to a proximal section having a larger configuration to facilitate introduction over a guidewire to enhance deliverability into the vasculature. Figure 2A A similar support bracket (or bracket) or other expandable support structure as shown in .

[0166] Figure 4Ais an example of an “expanded” view of a support stent or other expandable support structure having a helically arranged circumferential support ring constructed in accordance with the principles of the present invention.

[0167] Figure 4B yes Figure 4A Detailed view of the adjacent circumferential support ring supporting the expandable distal tip of the stent.

[0168] Figure 4C is a polymeric tubular envelope (one or more membranes) incorporated in an unexpanded configuration (such as in a delivery configuration) Figure 4A An image of the support unit space.

[0169] Figure 4D The integrated membrane / expandable stent is shown after radial expansion from the delivery configuration to the expanded configuration by a balloon. Figure 4C Image of a support stent and a polymer tubular envelope (one or more membranes).

[0170] Figure 5A is an "expanded" view of another example of a support stent having a helically arranged circumferential support ring constructed in accordance with the principles of the present invention.

[0171] Figure 5B yes Figure 5A Detailed view of the adjacent circumferential support ring supporting the expandable distal tip of the stent.

[0172] Fig. 6A is an "expanded" view of another example of a support stent having a helically arranged circumferential support ring constructed in accordance with the principles of the present invention.

[0173] Figure 6B yes Fig. 6A Detailed view of the adjacent circumferential support ring supporting the expandable distal tip of the stent.

[0174] Figures 7A to 7AR-2 Various alternative examples of support element geometries, bracket designs, and connection locations and shapes of the present invention are shown.

[0175] Figure 8 is an "expanded" view of another example of a support bracket constructed according to the principles of the present invention, which has adjacent linked circumferential support rings, with different numbers of crowns, gap widths, unit periods, frequencies of unit amplitudes, and different construction examples of the support elements of the circumferential support rings.

[0176] Fig. 9A is an "expanded" view of an alternative example of a support stent constructed in accordance with the principles of the present invention having a helically arranged circumferential support ring without support elements.

[0177] Fig. 9B yes Fig. 9A Detailed view of the adjacent circumferential support ring supporting the expandable distal tip of the stent.

[0178] Fig. 9C An alternative example of a support stent of the present invention is shown having discrete support pads (or islands) located between the struts of a serpentine support ring.

[0179] Figures 10A-10G A method for advancing and expanding (deploying) an aspiration catheter in a patient's vasculature according to the principles of the present invention is shown. Figure 1 Exemplary use of the system.

[0180] Fig.11A Detailed view of an expandable distal tip of an alternative example of an aspiration catheter of the present invention having a support stent comprising a plurality of rings shown in a non-expanded configuration with a portion of the covering membrane removed or detached. FIG. 11 also shows a transition ring comprising an expandable portion and a non-expandable portion (a coil in this example). It also shows that the expandable stent and the non-expandable coil are continuously formed from the same tube or curved wire.

[0181] Fig. 11B yes Fig.11A A "deployed" view of a support stent at an expandable distal tip of an aspiration catheter of the system, showing the transition from the expandable stent at the distal tip to a non-expandable support stent formed as a helical coil in the body of the aspiration catheter.

[0182] Fig. 11C yes Fig.11A Detailed view of the individual cells of the support stent at the expandable distal tip of the aspiration catheter of the system, showing the recessed support elements and the compressed pattern configuration in the patterned configuration (or delivery configuration). Fig. 11C It is also shown that the arc length of the crown is about the same length as the axial length of the strut.

[0183] Fig.11D yes Fig.11A A magnified “expanded” view of the support stent at the expandable distal tip of the aspiration catheter of the system, showing details of the flush distal end ring.

[0184] Fig.11E and Fig.11F is an alternate detailed view illustration of a transition region between an expandable stent supporting the distal tip of an aspiration catheter of the present invention and a fixed diameter reinforcement structure shaft region of an aspiration catheter of the present invention.

[0185] Fig.11G and Fig.11H Recessed and protruding cantilever support elements of the present invention are shown.

[0186] Fig.11I and Fig.11J Exemplary helical support structures comprising two and three nested continuous helical rings are shown, respectively.

[0187] FIG. 12A to FIG. 12D The diagram is shown in an alternative expanded configuration (expanded) FIG. 11A to FIG. 11C A support stent is provided at the expandable distal tip of the aspiration catheter.

[0188] Fig.12E The non-expanded configuration is shown in FIG. Fig. 12A The stent is similar to the stent shown in FIG, but has a reduced diameter at the tip to facilitate enhanced deliverability over a guidewire into the vasculature.

[0189] Figure 13A-13G A device for advancing and deploying in the vasculature of a patient according to the principles of the present invention is shown. Figures 11A-11D Suction catheter Figure 1A use of the system.

[0190] Fig.14A and Fig. 14B It is shown how the "pitch angle" described herein may be determined as an acute angle.

[0191] Figure 14C-14E Distal tip support stents with different pitch angles and different inter-annular gap lengths are shown.

[0192] Figure 15A-Figure 15C are detailed exemplary views showing different bending patterns that may be used with the radially expandable distal tip ring of the present invention.

[0193] Fig.15D and Fig.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] Fig.16 It is shown how the faceted outer surface of the radially expandable distal tip ring of the present invention approaches a circular outer edge as a measure of roundness.

[0195] Fig.17 Various features of the rings that may be used to define the stent or structure of the helical, radially expandable distal tip of the present invention are identified.

[0196] 18A to 18C are side, perspective, and "expanded" views of an expandable stent comprising a plurality of laterally oriented, axially linked (or connected) expandable rings.

[0197] Fig.19Various features that can be used to define the structure of an expandable stent comprising a plurality of transversely oriented, axially linked (or connected) expandable rings, such as Figures 18A-18C The expandable ring shown in .

[0198] Fig. 20A and Fig. 20B is a side view and a "deployed" view of an expandable stent comprising a plurality of parallel, axially linked (or connected) expandable rings that are inclined relative to the longitudinal axis of the stent.

[0199] Fig.21 is an “expanded” view of an expandable stent having segments with cells aligned in-phase and out-of-phase.

[0200] Fig. 22 is an “expanded” view of an expandable stent comprising a plurality of rings with gaps of varying lengths between the rings.

[0201] Fig.23A is a “deployed” view of an expandable stent comprising a plurality of rings arranged in a spiral pattern with gaps between the rings.

[0202] Fig. 23B yes Fig.23A Detailed exemplary view of the rings showing that each ring has a serpentine pattern.

[0203] FIG. 23C to FIG. 23E yes Fig.23A Rotated side view of the expandable stand.

[0204] Fig.24A is a “deployed” view of an expandable stent comprising a plurality of rings arranged in a helical pattern with gaps therebetween, wherein a single ring has a first curved shape in the deployed pattern.

[0205] Fig. 24B yes Fig.24A A detailed view of the rings, showing that each ring has a serpentine pattern.

[0206] FIG. 24C to FIG. 24E yes Fig.24A Rotated side view of the expandable stand.

[0207] Fig.25A is a “deployed” view of an expandable stent comprising a plurality of rings arranged in a helical pattern with gaps therebetween, wherein a single ring has a second curved shape in the deployed pattern.

[0208] Fig.25B yes Fig.25A Detailed exemplary view of the rings showing that each ring has a serpentine pattern.

[0209] FIG. 25C to FIG. 25E yes Fig.25A Rotated side view of the expandable stand.

[0210] Fig.26 is an "expanded" view of an annular pattern comprising S-shaped expandable elements connected by non-expandable circumferential links shown prior to expansion.

[0211] Fig. 27 is an “unfolded” view of an annular pattern comprising curved lines with integrated cantilevered support elements.

[0212] Fig.28A and Fig.28B "Expanded" views of the closed cell box ring pattern shown in its non-expanded and expanded configurations, respectively.

[0213] Fig.29A and Fig.29B "Expanded" views of a closed cell box ring pattern shown in its non-expanded and expanded configurations, respectively, the closed cell box ring pattern further comprising cantilevered support elements recessed between circumferentially adjacent box elements in the non-expanded configuration.

[0214] Fig. 30A and Fig. 30B "Expanded" views of an alternative closed cell box ring pattern shown in its non-expanded and expanded configurations, respectively, the alternative closed cell box ring pattern further comprising cantilevered support elements recessed between circumferentially adjacent box elements in the non-expanded configuration.

[0215] FIG. 31A to FIG. 31C An exemplary method for embedding a radially expandable support stent or other structure in a polymer film is shown.

[0216] Fig.32 is shown in a radially expanded configuration through FIG. 31A to FIG. 31C Cross-sectional view of the distal tip region manufactured by the method. DETAILED DESCRIPTION

[0217] Reference now Figure 1, a system 10 for removing a clot from a patient's vasculature (typically the cerebral vasculature) includes an aspiration catheter 12 and a distal tip extension 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 the proximal end, and a Luer connector / connector 24 is configured to be attached to a syringe or other vacuum or negative pressure source type typically found in a hospital or other medical institution. By applying negative pressure to the Luer connector / connector 24, the clot can be aspirated into the open distal end of the expandable distal tip 18, as described in more detail below. The diagram of the system 10 shows a proximal hub 20 having a Luer connector / connector 24 connected to a guidewire lumen (not shown), which is also the same lumen as the aspiration lumen in this example. The guide wire is typically removed before attaching the luer / connector 24 to the vacuum pump in order to maximize suction force. In another example, the system 10 can be adapted to have a proximal hub similar to the proximal hub 30, where the luer / connector 34 will connect to the vacuum pump and the luer / connector 32 will connect to the guide wire lumen (not shown).

[0218] The distal tip extension catheter 14 includes a balloon or other expandable member 26 located at the distal end of the 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) that extends the entire length of the shaft 28 and allows the catheter 14 to be advanced to a target location in the patient's brain or other vasculature over a guidewire or microcatheter. The second Luer connector 34 is configured to connect to a balloon inflation lumen (not shown) in the shaft 28, which allows the expandable distal tip 18 of the aspiration catheter 12 to be expanded to the vicinity of a target clot in the patient's vasculature, as will be described in more detail below.

[0219] Figure 1A Shows the suitability with Figure 1A second exemplary aspiration catheter 112 is provided for use with a distal tip expansion catheter 14 of the present invention. The aspiration catheter 112 has a construction similar to that of the aspiration catheter 12, and includes 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 a suction cavity extending from its distal end to the proximal end, and the Luer connector 124 at the proximal end of the tubular body 122 is configured to be attached to a vacuum pump or negative pressure source type typically found in a hospital or other medical institution. By applying negative pressure to the Luer connector / connector 124, the clot engaging the distal tip can be aspirated to the open distal end of the expandable distal tip 118, as described in more detail below. The diagram of the aspiration catheter 112 shows a proximal hub 120 having a Luer connector / connector 124 connected to a guide wire cavity (not shown), which is also the same cavity as the aspiration cavity in this example. The guide wire is typically removed before the Luer connector / connector 24 is attached to the vacuum pump. In another example, the suction catheter 124 may be adapted to have a similar Figure 1 The proximal hub 30 of the embodiment of the present invention is a proximal hub of the embodiment of the present invention, wherein the luer connector / connector 34 will be connected to the vacuum pump and the luer connector / connector 32 will be connected to the guide wire lumen (not shown).

[0220] and Figure 1Compared to the aspiration catheter of the present invention, the expandable stent 118 of the aspiration catheter 112 is connected to or attached to or coupled at its proximal end to a typically non-expandable reinforcement structure (such as a coil 128, typically a helical ribbon), which can be formed integrally (or continuously) with the helical expandable stent 118. Although the reinforcement coil 128 can be formed of the same balloon-expandable stent material (e.g., a wrought metal including a metal or metal alloy) as the expandable stent of the distal tip 118, the reinforcement coil typically will not be radially expandable by a distal tip expansion catheter (such as a balloon catheter) because it is not constructed with a wavy pattern including bends and struts or otherwise allows radial expansion, as described in more detail below. In some cases, the thickness of the reinforcement coil 128 will typically be the same as the thickness of the expandable stent of the distal tip 118. Similarly, the reinforcement coil 128 will typically have an absolute pitch angle similar to the pitch angle of the expandable stent, wherein the pitch angle is preferably in the range of 80° to 89.9° relative to the longitudinal axis in the patterned configuration or delivery configuration. In some other cases, the reinforcement coil 128 will have an absolute pitch angle in the range of 70° to 89.9°, preferably in the range of 80° to 89.9° relative to the longitudinal axis in the patterned configuration or delivery configuration. In some cases, the width of the reinforcement coil 128 will typically range from about the same as the width of the expandable ring of the expandable stent to 3 times the width of the expandable ring of the expandable stent of the expandable tip 118. In some other cases, the width of the reinforcement coil 128 ranges from 0.05mm to 0.25mm, and the gap of the reinforcement coil 128 ranges from 0.025mm to 0.25mm. In some examples, the gap between the coils is fixed. In other examples, the gap between the coils is variable. In some cases, the reinforcement coil 128 is integrally formed from the same tube or bent wire that forms the expandable stent of the expandable tip 118. The tube or bent wire is patterned to form a plurality of adjacent ribbons, loops, or turns that are continuously connected end to end in a spiral arrangement, which is typically patterned by a laser, bent wire, or other device. In other cases, the reinforcement coil 128 is formed from a bent wire that forms a plurality of adjacent turns that are continuously connected end to end in a spiral arrangement. In this example, the expandable stent of the expandable tip 118 is formed from the same tube as the coil 128, wherein the expandable stent is formed from a tube that is patterned to form a plurality of adjacent loops that are continuously connected end to end in a spiral arrangement, wherein each loop includes a structural element comprising struts connected by a crown, and wherein the absolute pitch angle of the expandable coil stent ranges from 70° to 89.9°, or preferably ranges from 80° to 89°.For example, the distal tip expandable stent 118 can be covered with an expandable membrane, which includes one or more membranes, wherein one or more membranes are elastic and / or inelastic but stretchable membranes (allowing expansion), which cover the expandable stent 118 and extend from the distal end of the distal tip to at least the proximal end of the expandable stent. In some cases, the expandable membrane extends proximally to the proximal end of the expandable stent to cover at least one section of the reinforcement coil 128, or in some cases extends proximally to substantially cover the entire length of the reinforcement coil 128. In some other cases, the reinforcement coil 128 can be covered with one or more elastic membranes and / or inelastic membranes (resistance to expansion) that are different from the one or more membranes covering the expandable stent 118. In some cases, the one or more expandable membranes covering the expandable stent are attached to the inner surface and / or outer surface of the expandable stent. In other cases, the expandable stent is laminated in one or more expandable membranes covering the outer surface of the expandable stent and / or covering the inner surface of the expandable stent, embedded in the one or more expandable membranes or in the one or more expandable membranes, or coated by the one or more expandable membranes. In some cases, the expandable stent is covered by at least two films, one of which is attached to the outer surface of the expandable stent and the other is attached to the inner surface of the expandable stent. In other cases, the suction catheter includes an expandable tip, wherein the expandable tip includes an expandable membrane and an expandable support structure (such as a stent), wherein the expandable stent includes a plurality of rings spaced apart along the longitudinal axis, and there are gaps between the plurality of rings and within each ring, wherein the ring includes a structural element, and the structural element includes a strut and a crown. The expandable stent is embedded in or within one or more expandable membranes, wherein the expandable membrane covering the stent includes at least one membrane, wherein at least one membrane softens and / or melts on the outer surface of the expandable stent and / or on the inner surface of the expandable stent, thereby allowing one or more expandable membranes to soften or melt and protrude or flow into the gaps present in each ring (in each ring structural element) and the gaps present between the rings, and the material adheres to the rings (ring structural elements), thereby providing an integrated expandable stent / membrane system, which can be expanded from a contracted or delivered structure to an expanded larger structure.In a preferred aspect, the expandable film covers the outer surface and / or the inner surface of the expandable support structure or stent, and also covers at least some of the gaps present in each ring of the expandable stent and the gaps present between adjacent rings of the expandable stent, wherein the covering includes one or more of the following: coating the outer surface of the stent, the inner surface of the stent, and / or the gaps between the outer surface and the inner surface of the stent, providing a fluid seal to the outer surface of the stent, the inner surface of the stent, and / or the gaps between the outer surface and the inner surface of the stent, filling the outer surface of the stent, the inner surface of the stent, and / or the gaps between the outer surface and the inner surface of the stent, flowing into the outer surface of the stent, the inner surface of the stent, and / or the gaps between the outer surface and the inner surface of the stent. The covering film is preferably disposed on the outer surface of the stent, the inner surface of the stent and / or the gap between the outer surface and the inner surface of the stent, or is adhered to the outer surface of the stent, the inner surface of the stent and / or the gap between the outer surface and the inner surface of the stent, embedded in the outer surface of the stent, the inner surface of the stent and / or the gap between the outer surface and the inner surface of the stent, laminated on the outer surface of the stent, the inner surface of the stent and / or the gap between the outer surface and the inner surface of the stent, wherein the covering film is sufficiently adhered to the stent ring structural elements to provide an integrated system that can be expanded together from a delivery structure to an expansion structure as an integrated system. The expandable membrane of the preferred aspect covers at least some of the following, preferably covers most of the following, and most preferably covers all of the following: flows into the gaps between each ring, including each of the ring structural elements of the pillars connected by the crown, wherein one or more expandable membranes of the preferred aspect cover the outer surface and / or inner surface of the expandable stent, and cover at least some side surfaces of the expandable stent structural elements, preferably cover substantially all side surfaces of the expandable stent structural elements, and cover substantially all gaps between adjacent rings of the expandable stent. The expandable stent of the preferred aspect includes an outer surface, an inner surface, and two side surfaces. On the other hand, the expandable stent is formed by a curved wire including an outer surface and an inner surface. In some other cases, the reinforcement coil material 128 can be formed of a material different from the expandable stent material 118, such as formed of a shape memory metal material, or formed of other forgeable metals or metal alloy materials, and then attached to the proximal end of the expandable stent by solder, or coupled to the proximal end of the expandable stent by abutting or winding (nesting or interweaving) two material ends and covering them with one or more films to keep them together. The one or more films covering the coil 128 can be the same as the one or more films covering the expandable stent 118. In another example, at least one film covering the coil 128 is the same as the film covering the expandable stent 118 , typically at least the same as the inner surface film covering both the expandable stent 118 and the reinforcement coil 128 .The expandable coil support 118 can be formed by a tube forming a plurality of circumferentially expandable rings, and the plurality of circumferentially expandable rings include structural elements comprising struts connected by crowns. Similarly, the reinforced non-expandable coil 128 can also be formed by the same tube forming a spiral ribbon. The expandable support rings, structural elements, struts and crowns, and the spiral ribbon of the reinforced coil each have an outer surface, an inner surface, and at least two side surfaces. In other examples, the expandable coil support and the reinforced non-expandable coil can be alternatively formed by a curved wire forming the expandable coil 118 and the reinforced coil 128.

[0221] The catheter body 122 includes two additional regions, a middle region 130, typically reinforced with a helical ribbon, and a proximal region 132, typically reinforced with a braid. The middle region 130 will have an "intermediate" flexibility between the flexibility of the flexible regions 118 and 128 and the flexibility of the more rigid and pushable proximal region 132. The distal end of the proximal region 132 is connected to the proximal end of the middle region 130 by overlapping their ends and covering the connection 1A-1 with a first adhesive sheath 140, wherein the adhesive sheath includes one or more films that are heated to a temperature sufficient to soften and / or melt the material, and wherein the material flows or protrudes into the metal structure gap sufficient to adhere to the metal structure, thereby holding the two structures, regions or segments together, and the distal end of the middle region 130 is connected to the reinforcement coil 128 by nesting their ends (wrapping their ends) and covering the connection 1A-2 with a second adhesive sheath 142, wherein the adhesive sheath includes one or more films that are heated to a temperature sufficient to soften and / or melt the material, and wherein the material flows or protrudes into the metal structure gap sufficient to adhere to the metal structure, thereby holding the two structures, regions or segments together. The adhesive sheaths can be the same or different. As Figure 1A-1 and Figure 1A-2As shown, the outer adhesive sheath 140 and 142 are typically overlapped with several nested or interwoven coils of the winding area connection 1A-2 or a longer segment than the connection 1A-2, or overlapped with the coil area / braided area of ​​the proximal region 132 The overlap connection 1A-1 overlaps some distance, preferably overlaps a short distance. The middle region 130 is typically formed integrally or continuously with the regions 128 and 118, and is typically a spiral coil that is configured to have a pitch angle, width, and gap different from the region 128 spiral coil to provide better thrust transmission. In other examples, 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 connected to the braided proximal shaft 132. In yet other examples, the middle region 130 is formed of different metals (such as shape memory metals or metal alloys (such as nitinol)) and is formed into a coil with a pitch angle, coil width, and gap between the coils to enhance the flexibility and pushability of the middle region 130. The expandable stent of region 118 is preferably formed by a tube, but may also be formed by a curved wire. Region 128 is preferably formed by the same tube that forms the expandable region 118 in an integrated manner. Region 130 is typically formed by the same tube that forms region 128 and / or region 118, but may also be formed by different materials or tubes or curved wires. In a preferred example, the region 18 expandable stent is formed by a tube that forms a structural element having an outer surface, an inner surface, and a side surface, wherein the structural element includes a strut connected by a crown that forms a plurality of adjacent rings that can be expanded from a curled configuration to an expanded configuration. Regions 128 and 130 are preferably formed by a tube (preferably the same tube) that forms the expandable stent region 118 in an integrated manner, wherein region 128 is formed in the form of a spiral coil. Although the reinforcement structure is typically a coil, other types of reinforcement structures (such as a stent, a support stent) can replace the coil in region 128 and are usually formed continuously with the expandable support stent of region 118. In other cases, region 118 may be formed of a shape memory alloy, such as Nitinol, and constrained in a delivery configuration before being released to expand from the delivery configuration to an expanded configuration.

[0222] Figure 1B Shows Figure 1 The system in is introduced via the femoral artery FA to a target location having a clot C in the cerebral vasculature CV. A guide wire GW is introduced into the femoral artery FA through a sheath (not shown). Figure 1 or Figure 1AThe aspiration catheter 12 is introduced via a guide wire GW and advanced through a guide catheter and / or an introducer sheath (not shown) through the femoral artery FA and through the aorta A into, for example, a target cerebral artery CA until the expandable distal tip 18 is located near or engaged with the target clot C. The distal tip extension catheter 14 is then advanced through the hemostatic valve HV via the guide wire, 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 substantially engages the clot and / or seals against the inner wall of the cerebral artery and / or expands toward the inner wall of the cerebral artery at a location near the clot C. The geometry of the expanded distal tip 18 can vary (as described below), 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 draw the clot C into the aspiration catheter 12 so that the clot C can be removed from the vasculature.

[0223] Reference now FIG. 2A to FIG. 2C , will be described in more detail Figure 1 The expandable distal tip 18 of the suction catheter 12 in the embodiment of the present invention is a structure of an expandable distal tip 18. The expandable distal tip 18 includes both an expandable support stent 38 and an expandable membrane 40. As previously described, the expandable membrane 40 will typically include one or more elastic or stretchable non-elastic polymer films with a support stent 38, and the support stent 38 is embedded or laminated therein to cover the stent. The support membrane typically flows into the support stent structural element, protrudes to the support stent structural element, or is otherwise adhered to the support stent structural element, thereby providing an integrated expandable stent membrane system. The support stent 38 will typically include a metal or a metal alloy, typically formed of a wrought metal or metal alloy, and the stent is configured for balloon expansion, but in other cases, it can be configured to self-expand after being released from the constraint.

[0224] The support bracket 38 includes a plurality of radially expandable circumferential support rings 42, and each ring is separated from the adjacent ring by a gap. The ring will generally include a wavy pattern, such as a serpentine, box-shaped or zigzag pattern, which includes a support 48 connected by a crown 50, wherein adjacent rings 42 can be connected by an axial connecting rod 46. The support bracket 38 shows a vertical ring with about 90° relative to the longitudinal axis, and the support bracket 38 can alternatively be formed by multiple rings with an acute pitch angle relative to the longitudinal axis in a patterned or delivery structure (not shown), and the pitch angle is preferably in the range of 70° to 89.9°. In a preferred example, adjacent rings are connected by a connecting rod, or no more than one connecting rod, or no more than 2 connecting rods (not shown). The connecting rod can have various shapes, such as offset linear (as shown) or other types of linear or nonlinear shapes, such as U, M, Z, S or other shapes. In another example (not shown), at least some of the adjacent rings are not connected together, but are held together by a film covering, shrinking onto, coating or melting at least some of the rings, thereby allowing the rings to be held together in the delivery configuration and expanded from the delivery configuration to the expanded configuration. Although adjacent rings are typically connected by one or more connecting rods, alternatively, sometimes structural elements on adjacent rings are welded or fused or attached together, thereby connecting adjacent rings at one or more locations. Alternatively (not shown), the support bracket 38 can be formed by an expandable coil, wherein the expandable coil includes a plurality of adjacent expandable rings (or turns) connected continuously end to end in a spiral arrangement, each ring includes a structural element, the structural element includes a support element and a strut connected by a crown, and the expandable coil has an acute pitch angle relative to the longitudinal axis in the range of 70° to 89.9°, preferably in the range of 800 to 89° in the patterned or delivery configuration. The expandable loops of the expandable coil supporting the stent are continuously connected end to end in a spiral arrangement and are typically not otherwise connected (such as by connecting rods or by attaching structural elements or attachment points on adjacent loops). In some limited cases, at least some of the loops of the expandable coil may be connected by one or more connecting rods or by attaching structural elements or attachment points on adjacent loops (typically at Figure 1AThe expandable coil is connected to provide support by attaching a structural element on a ring at the proximal end of the region 118 of the expandable stent. In a preferred example, the expandable coil is expanded from a delivery configuration or a contracted configuration to an expanded configuration by an expandable support structure (such as a balloon catheter) that expands radially inside the expandable coil, wherein the expandable coil is referred to as balloon-expandable. Alternatively, the support stent can be formed by a curved wire that forms a plurality of adjacent turns that are continuously connected end to end in a spiral arrangement. The expandable coil can be formed by a tubular body and patterned to include a plurality of circumferential expandable rings. In a preferred example, there are gaps between at least some of the rings of the expandable stent, and preferably, there are gaps between all adjacent rings of the expandable stent. As shown in these figures, the gaps between adjacent rings are typically fixed ( Figure 2A , Figure 2B and Figure 2C ), but in some cases the gap may have a variable axial length (not shown).

[0225] In an exemplary embodiment of the present invention, the support element 52 of the expandable stent 38 is located between adjacent struts 48 pairs and has a base end 56 attached to the inner radius of the crown 50, and the crown 50 connects the strut to the adjacent support member facing the opposite axial direction. In this way, the support element 52 reinforces the region across (extending through) the strut 48 of the expandable membrane 40. In addition, in this preferred example, the length of the support element 52 is equal to or shorter than the ring period, so that it will not extend to the gap area between adjacent rings (as shown in the figure). This enhances the delivery ability of the stent and strengthens the region of the expandable membrane. The length of the support element 52 is longer than 1 / 2 of the length of the adjacent struts, and the length is equal to or shorter than the adjacent ring period (as shown in the figure). This provides a balance between the region of the reinforced expandable membrane and the delivery ability of the enhanced stent. The support element 52 in this example has an axial length, a base and a free end, wherein the free end terminates at the beginning of the gap area between the rings or before the beginning of the gap area between the rings (as shown in the figure). In rare cases, the length of the support element can extend beyond the peak of the adjacent crown, extending into the gap area between the rings (not shown). In this preferred example, the support elements 52 in each ring have the same length. In this preferred example, the support elements 52 in at least some rings or in the entire length of the stent have the same length (as shown). However, the support elements in one ring can have different lengths (not shown), or the support elements on adjacent rings can have different lengths (not shown), or the support elements on at least some rings are different (not shown). In some examples, the width of the support element 52 is the same in each ring and is also the same in multiple rings (as shown). However, the width of the support element can be different in one ring or in multiple rings (not shown). In a preferred example, the width of the support element 52 is approximately the same as the width of the adjacent structural element (such as an adjacent crown or pillar). Alternatively, the width of the support element 52 is equal to or greater than the width of the adjacent structural element (such as an adjacent crown or pillar). In other examples, the width of the support element 52 is greater than the width of the adjacent structural element (such as an adjacent crown or pillar). In yet another other example, the width of the support element 52 is less than the width of the adjacent structural element (such as an adjacent crown or pillar). In some cases, the width along the length of the support element or along a structural element (such as a pillar or crown) can be different. In this example, the width is the average of the maximum width and the minimum width along the length of the support element or structural element. Each of the support elements 52 has a base end 56, which is attached / connected to the radially expandable circumferential support ring 42. The base end 56 typically has the same width as the rest of the support element (as shown), but in other examples, the width of the base end can be greater than the width of the support element. Each of the support elements has a free end 58, which extends into the area between adjacent pillars.The free end 58 has a circular shape (as shown), or in other examples may have a flat shape (not shown), a T-shape (not shown) or other shapes or configurations. Although the support element 52 is shown as being attached to the inner radius or wall of the crown 50 and being linear, in other examples, the support element may be attached to other locations on the support ring 42 (such as being attached to a pillar) and be linear or non-linear. In this example, at least some of the support elements are connected to each radially expandable circumferential support ring 42. In this example, at least some of the support elements are connected to at least some of the radially expandable circumferential support rings 42. In this example, at least some of the support elements are connected to substantially all of the radially expandable circumferential support rings 42. In this example, at least some of the radially expandable circumferential support rings, each of which includes a plurality of units, each of which includes a pillar connected by a crown, wherein at least one support element is connected to each unit on at least some of the expandable rings (as shown). In this example, at least one radially expandable circumferential ring, wherein the ring includes a plurality of units, each of which includes a pillar connected by a crown, wherein at least one support element is connected to each unit on the expandable ring (as shown). In this example, at least one radially expandable circumferential ring, wherein the ring comprises a plurality of cells, wherein each cell comprises struts connected by a crown, wherein at least some of the support elements are connected to at least some of the cells on the expandable ring (eg. Figure 2C In this example, at least some radially expandable circumferential support rings, each of which includes a plurality of cells, each of which includes struts connected by a crown, wherein at least some of the support elements are connected to at least some of the cells on at least some of the expandable rings (as shown). Figures 7A to 7AR-2 Describes various attachment locations and support member geometries.

[0226] Typically, but not necessarily, the support bracket 38 will be, for example, Figure 2B The "unfolded" pattern shown is laser cut from a metal tube. The pattern includes a helical coil 44 ( Figure 1A The helical coil 128 is continuously patterned from the same tube that forms the expandable stent, and the helical coil 44 is intended to support at least a portion of one or more membranes 22, such as Figure 2AAs shown. The length of the reinforcement coil ranges from 1 mm to 100 cm, preferably ranges from 1 cm to 50 cm, and more preferably ranges from 1 cm to 25 cm. The reinforcement coil has an acute pitch angle, width, and thickness as discussed previously. The spiral coil will have a gap between the coils ranging from 0.01 mm to 0.25 mm. One or more membranes 22 can be the same as or different from one or more expandable membranes 40. In one example, at least one membrane 40 extends from the distal end of the distal tip to the proximal region, wherein the proximal region surrounds the proximal end of the coil 44. In another example, at least one membrane 22 forms, coats, or covers at least some of the coil length, preferably covering the entire coil 44 length. In this case, the membrane 22 is formed of a harder material to provide a more rigid feel to the coil. Figure 1A The coil region 128 provides enhanced support (reinforcement). In this case, at least one membrane 22 and at least one membrane 44 will typically be joined, fused or attached at the interface of the expandable stent 38 and the reinforcement coil 44 (as shown). The length of the reinforcement coil 44 can extend to Figure 1A The proximal portion of the tubular body 122 may extend over the entire length of the tubular body 122, but more typically will only extend to a shorter transition region at the distal end of the tubular body. The proximal portion of the tubular body 122 may typically have braiding or other forms of reinforcement.

[0227] like Figure 1 and Figure 2A-2C As shown, the expandable distal tip 18 of the aspiration catheter and the support stent 38 are in their non-expanded configuration (or in a delivery configuration) suitable for introduction through the patient's vasculature to a target clot location. Figure 2A As shown, the expandable stent 38 and the reinforcement coil 44 connected to the proximal end of the expandable stent have the same inner diameter and / or outer diameter, or have the same configuration as the delivery configuration, to facilitate introduction through the patient's vasculature. Alternatively (not shown), the expandable stent segment 38 can have a smaller delivery configuration than the reinforcement coil segment connected to the proximal end of the stent to enhance the delivery capabilities of the suction catheter. However, once at the target clot location, the expandable distal tip 18 and support structure 38 will expand to engage the clot or the vessel wall near the clot, as described below with reference to Figures 10A-10G Described in more detail. FIG. 2A to FIG. 2CThe support element in the embodiment includes at least one support element contained in each unit on a ring or contained in at least some units on a ring, forming a circumferential envelope around the perimeter of the stent along the stent length or along the entire stent length. The circumferential envelope typically has a fixed axial length, width, shape, number of support elements per ring, pitch angle and / or geometry (as shown), and provides support for one or more expandable membranes to resist the collapse of one or more expandable membranes after expanding from the delivery structure to the expansion structure and applying vacuum at the proximal end of the suction catheter and the distal tip is blocked or blocked by clots or other substances. In this example, the support element is contained in each unit on a ring, or in each ring amplitude, preferably, contained in the space of the struts connected by the crown of the same ring, wherein the amplitude includes the axial distance between two adjacent peaks on the same ring. In some cases, the support elements can have different lengths, widths, shapes, missing support elements (one or more cells within the ring do not have a support element), pitch angles, and / or geometries within the ring or along at least some of the rings, wherein the different widths, lengths, shapes, missing support elements, or geometries maintain sufficient support for the expandable one or more membranes to prevent collapse of at least one or more membranes under vacuum in the expanded configuration when the distal tip becomes blocked or clogged with clot or other material.

[0228] like Figure 3A-3D As shown, the expandable distal tip 18 (expandable membrane not shown) can be expanded into a variety of different geometric shapes. Typically, the expanded geometry will be roughly cylindrical 38a, such as Figure 3A As shown, or may have a tapered tip (not shown) at a generally cylindrical distal end. In other cases, the expanded geometry may be generally conical 38b, wherein the base of the cone forms an enlarged distal opening for receiving a clot, such as Figure 3B In still other cases, the extended geometry may combine extended and tapered portions 38c and 38d, such as Figure 3C and Figure 3D Typically, the different expanded 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. However, in other cases, the support scaffold 38 will be elastic or superelastic and preformed into the desired expanded geometry when unconstrained by heat treatment or other means, such as FIG. 3A to FIG. 3D Those shown in .

[0229] Reference now Figure 3EIn some cases, the unexpanded or delivered diameter (configuration) of the support stent 38e can be reduced to facilitate initial introduction over a guide wire. In particular, the support stent 38e can have an unexpanded (delivered) reduced diameter (configuration) relative to the diameter (configuration) of the coil support region 44e, which represents the diameter (configuration) of the tubular body (not shown). Figure 3A-3D As shown, the proximal end of the expandable stent is typically continuously connected to a non-expandable support structure, such as a coil (eg, Figure 3A-3D As shown), spiral coil (as Figure 3E ) or a non-expandable stent (not shown), or other support or reinforcement structure (not shown). Figure 3A-3E As shown, the distal end or turn of the reinforcement coil is connected to the proximal ring of the expandable stent on the crown peak (as shown). Alternatively (not shown), the distal end of the reinforcement coil can be connected to the proximal ring at at least one position, at least two positions, or at least three positions, wherein the position on the ring can be on the crown peak, on the crown groove, and / or on the strut. The distal end of the reinforcement coil can typically be connected to the proximal ring of the expandable stent via an axial connecting rod (as shown). The axial connecting rod can be linear, nonlinear, offset, or have various shapes, such as U, M, W, Z, or S. Alternatively, the distal end of the coil can be directly connected to one or more positions on the proximal ring without a connecting rod (not shown). In this example, in the patterned or delivery structure, the reinforcement coil has an acute pitch angle of about 90° relative to the longitudinal axis. Alternatively, in the patterned or delivery structure, the pitch angle can alternatively be in the range of 70° to 89.9° relative to the longitudinal axis. Figure 3A-3D The reinforcement coil in FIG. 1 shows that the reinforcement coil turns are not connected by connecting rods. In some other examples, the reinforcement coil can have one or more connecting rods that connect at least some adjacent turns of the coil to enhance support for the reinforcement coil area. Alternatively, at least some adjacent turns can be connected by welding points on the adjacent turns or by other means. Figure 3A-3E An expandable stent comprising expandable rings is shown, with adjacent rings connected by at least one connecting rod. In an alternative example (not shown), Figure 3A-3EThe expandable stent can be formed by a circumferential expandable ring, wherein at least some adjacent rings are not linked or otherwise connected (by connecting rods or other means), and wherein the adjacent rings are held together by one or more films, and the one or more films laminate the expandable stent between the layers of the tubular film. In a preferred example, in a patterned or delivery configuration (as shown in the figure), the distal ring of the expandable stent preferably has a flush end and has a pitch angle of about 90 ° relative to the longitudinal axis. In some other examples (not shown), the distal ring of the expandable stent can have a tapered end. The tapered end ring can be constructed by controlling the pitch angle and / or by increasing the amplitude of at least some units on the end ring (or reducing the amplitude of at least some units), to achieve the desired distal taper. The end ring can have the same unit amplitude, the same unit period and / or the same unit width on at least some units in the end ring, or can have different unit amplitudes, different unit periods and / or different unit widths on at least some units in the end ring.

[0230] Reference now FIG. 4A to FIG. 4D , the support bracket 60 pattern includes support elements 68, which are attached to the outer curved walls of the crown 66 connecting adjacent struts 64. Figure 2A-2C In contrast to the pattern of support elements 68, support elements 68 do not extend between adjacent struts 64, but instead extend into the gaps or open spaces between adjacent radially extending circumferential support rings 62. A second difference is that support rings 62 are continuously linked end to end to form a spiral pattern. Figure 4C is shown having a radially retracted configuration suitable for delivery (or delivery configuration) Figure 4A and Figure 4B Image of the expandable area of ​​the stent-patterned aspiration catheter. Figure 4D yes Figure 4C , after the structure has been expanded by a balloon to an expanded configuration, preferably to a maximally expanded configuration suitable for aspiration. The distal ring is configured to have a flush end having a pitch angle of approximately 90° relative to the longitudinal axis in a patterned or delivery configuration (as shown). This end and the immediately adjacent rings may be configured in a variety of ways. In this example, the rings adjacent to the end rings are truncated along the circumferential path of the rings and connected to the end rings, as shown. Figure 4AAs shown. The end ring and the ring adjacent to the end ring can have different acute angles (or 90°) pitch angles (as shown). Alternatively, the ring before the end and the end ring can also have the same or different unit amplitudes, unit periods, structural element widths and / or crown quantities. The expandable stent 60 pattern has a pitch angle of about 86°. In other examples, in the patterned or delivery configuration, the pitch angle can range from 70° to 89.9° relative to the longitudinal axis, preferably ranging from 80° to 89°. It is important to note that even if the support elements extend into the gap region (or other space) between adjacent rings, these support elements typically do not extend into the adjacent ring region, thereby maintaining the enhanced delivery capability of the expandable stent segment in the vascular anatomical structure.

[0231] Reference now Figure 5A and Figure 5B , a support stent 70 having a spiral pattern similar to that of stent 60 includes a plurality of radially expandable circumferential support rings 72, and a plurality of radially expandable circumferential support rings 72 include struts 74 and crowns 76. Support elements 78 are different from support elements 68, and they have bifurcated end support disks. The support elements form a circumferential envelope around the stent perimeter along the stent length or along the entire stent length. The circumferential envelope typically has a fixed axial length, width, shape and / or geometry (as shown), and provides support for one or more expandable membranes to resist the collapse of one or more expandable membranes after applying vacuum at the proximal end of the suction catheter when the distal tip is blocked or blocked by clots or other substances from the delivery structure to the expansion structure. In this example, the support element base is located at the crown peak area. The support element axially extends beyond each ring amplitude or beyond at least some ring amplitudes, where the amplitude is the axial distance between two adjacent peaks on the same ring. In some cases, the support elements can have different lengths, widths, shapes, or geometries within a ring or along at least some of the rings, wherein the different widths, lengths, shapes, or geometries continue to provide support to the expandable one or more membranes to prevent collapse of at least one or more membranes under vacuum in the expanded configuration. Figure 5A , Figure 4A and Fig. 6A As shown, the proximal ring of the expandable stent is composed of an expandable segment (shown) and a non-expandable segment (truncated), defining a transition between the expandable stent and the reinforcement coil. The first non-expandable reinforcement coil segment can be attached to one or more locations on the adjacent expandable ring and / or adjacent reinforcement coil turns, or remain unattached instead of being attached to the adjacent turns in a spiral pattern.

[0232] Reference now Fig. 6A and Figure 6B, support stent 80 has a spiral pattern similar to the spiral pattern of stents 60 and 70, which includes a plurality of radially expandable circumferential support rings 82, and a plurality of radially expandable circumferential support rings 82 include struts 84 connected by crowns 86. Support elements 88 differ from support elements 68 and 78 in that they extend primarily in the circumferential direction, thereby allowing adjacent support rings 82 to be positioned very closely together in the axial direction before expansion. In this example, the support element extends into substantially the entire gap between the rings, leaving a small gap between adjacent rings. This type of support element configuration provides one or more membranes with enhanced resistance to collapse when the membrane is expanded from the delivery configuration to the expansion configuration and a vacuum is applied at the proximal end of the suction catheter. On the other hand, this design configuration with a smaller gap is more suitable for anatomical structures that are not tortuous. In this example and other examples, it is important to note the symmetry of the support element within each ring, preferably within at least some rings, and more preferably along substantially the entire length of the stent. This symmetry provides resistance to deformation and / or kinking when passing through the vascular system. It also provides an enhanced resistance to collapse of the expandable membrane. In some cases, one or more support elements may be missing within one or more rings, thereby providing an asymmetric support element pattern while still maintaining the expandable membrane's resistance to collapse.

[0233] As presently shown, the support element generally comprises a straight structure having a base end attached to a radially expandable circumferential support ring and a free end located in the space between adjacent struts, between adjacent struts connected by a crown, or in the gap between adjacent support rings. Figure 7A-Figure 7N As shown, the geometry and attachment locations of the support elements can vary widely. Fig. 7A The support element 104a shown has a base end attached to the inner radius or wall of the crown 102 and a V-shaped, The free end of the elliptical contact pad 105a terminates in the elliptical space. The elliptical contact pad 105a has a major axis aligned in the axial direction. Figure 7B As shown, the support element 104b terminates in an elliptical contact pad 105b having a major axis aligned in the circumferential direction.

[0234] Figure 7C The support element 104c in is similar to the support element described previously, except that it terminates in a triangular contact pad 105c having a pointed tip oriented away from the attached crown. Fig.7D The support element 104d in is similar to all the support elements previously described except that it terminates in a triangular contact pad 105d having an expanded base oriented away from the attached crown. Figure 7GThe support element 104g shown in FIG. 1 has a base attached to the center of the inner wall of the crown 102 and a circular contact pad 105g having a hole in its center circumferentially aligned with the attachment point.

[0235] Fig. 7E , Figure 7F , Figure 7H and Fig.7I A support element with a bent axis is shown. Fig. 7E The support element 104e shown in FIG. 1 has an S-shaped shaft with a base end attached on one side of the outer curve of the crown 102 and a circular contact pad 105e circumferentially aligned with the outermost point of the crown. Figure 7F The support element 104f shown in FIG. 1 has a base attached to the outermost point on the crown 102 and a circular contact pad 105f circumferentially aligned with the outermost point. Figure 7H The support element 104h shown in FIG. 1 has a base attached to the outermost point of the crown 102 , a shaft with a simple 90° bend, and a circular contact pad 105h axially offset from the outermost point. Fig.7I The support element 104i shown in has a base end attached along the length of the pillar 100, and a circular contact pad 105i attached to its free end. The shaft has a bend of approximately 120°.

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

[0237] In other examples, the support element may have bends, forks, multiple contact pads, and other structural features to enhance its ability to support the expandable membrane in the area between adjacent struts and / or adjacent support rings. Figure 7K As shown, the support element 104k is bifurcated into a Y-shape and has a pair of contact pads 105k. Figure 7L The support element 1041 is shown also having a bifurcated portion with a pair of contact pads 1051 and a third contact pad 1061 located at the bifurcated point.

[0238] In still other examples, the support elements may be formed as linked linear segments, optionally with contact pads at some or all of the connections between the links. Figure 7M and Figure 7NAs shown, support elements 104m and 104n each include a pair of linear segments having contact pads 105m and 105n at the distal free ends, respectively, and inner contact pads 106m and 106n at the connections between the segments, respectively. 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° angle).

[0239] Reference now FIG. 7O to FIG. 7R , shows various T-shaped support elements having a base end attached to the inner surface of the U-shaped crown. The T end can extend into the gap between adjacent rings and can be flush with any ring, such as Fig.7O and Figure 7P Alternatively, the T ends can be flush with the ring to which they are attached ( Figure 7Q ), or can extend into the middle gap without touching any rings ( Figure 7R ). In some examples, the support elements within each ring extend in the same direction, such as Fig.7O Alternatively, the support elements within each ring may extend in opposite directions, such as Figure 7P shown.

[0240] Reference now Figure 7S , a support element having a base end attached to the inner surface of the U-shaped crown can have an unattached end having a different end geometry extending into the gap between adjacent rings. For example, some of the ends can be provided with a buffer or stop element configured to engage adjacent rings to maintain a desired gap area therebetween.

[0241] Reference now Figure 7T , a support element having a base end attached to the inner surface of a box-shaped or U-shaped crown can have a recessed unattached end (free end) that fills substantially all of the space between adjacent struts on each ring (or fills or covers substantially all of the space between adjacent struts on each ring in a patterned or delivered configuration). This is a preferred ring geometry, as discussed in detail below FIG. 11A to FIG. 11D As shown in more detail in FIG.

[0242] Reference now Figure 7U to Figure 7Y and Figure 7P , showing various support elements having a base end attached to the outer surface of the U-shaped crown. The unattached end (free end) of the support element can have a T-shape, L-shape, skewed shape, or various other geometric shapes, and will extend completely or partially into the gap between adjacent ring elements. The end can be flush with the adjacent ring, such as Fig.7O , Figure 7U , Figure 7W , Figure 7X and Figure 7YAs shown, or an intermediate gap may be left without contacting adjacent rings ( Figure 7V ).

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

[0244] like Figure 7AE to Figure 7AP As shown, the support element can be formed as a "lock and key" structure, which includes a straight element or a male element slightly received in a slotted or "U-shaped clamp" member. Such a support element can accommodate circumferential movement and / or axial movement of adjacent ring elements when the stent is radially expanded. Such an expandable or adaptable support element can extend through the opening (such as the opening of the U-shaped unit (including a pair of struts connected by a crown) of the U-shaped unit. Figure 7AD and Figure 7AE ), or may extend from one ring to an adjacent ring (as shown in Figure 7AF to Figure 7AP The base end of the male element and / or the U-shaped clip element may be attached to the inner or outer surface of the crown, the inner surface of the strut, and may extend in the circumferential direction or may be inclined at an angle relative to the circumference. Either or both of the male element and the slash or U-shaped clip element may have one or more bends. Figure 7AE to Figure 7AP Various geometries and combinations are shown in FIG, but it should be understood that many other specific geometries may be utilized.

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

[0246] Reference now Figure 7AR , Figure 7AR-1 and Figure 7AR-2 , a particular serpentine ring arrangement includes a U-shaped unit having a U-shaped support element extending across the opening between adjacent crowns. The U-shaped support element is configured to move from a curled configuration (e.g., Figure 7AR-1 ) is extended to an extended construct (as shown Figure 7AR-2 shown).

[0247] Figure 8FIG. 1 is an “expanded” view of another example of a support stent 110 having adjacent linked radially expandable circumferential support rings 112 having different widths and different configurations of support elements 114 constructed in accordance with the principles of the present invention. As with the previous example, support rings 112 are comprised of pairs of struts 115 connected by crowns 116. Support elements 114a are similar to those of reference 114b. Figure 2A - The linear beam of the support element 52 depicted in FIG2D. The support element 114b has a single bend and is similar to Figure 7M 104m, but lacks the intermediate contact pads between adjacent linear segments and is attached to struts 115 rather than crowns 116. Support element 114c is a short straight beam with distal contact pads. Support element 114d has a similar Figure 7H The stent rings shown may have different numbers of crowns on adjacent rings, different unit periods on adjacent rings, different shapes, numbers, and frequencies of struts on adjacent rings, different gaps between rings, and / or different ring amplitudes.

[0248] like Fig. 9A and Fig. 9B As shown, the support stent 120 includes a plurality of radially expandable circumferential support rings 122, which include struts 124 and crowns 126. Unlike the previous examples, there is no support element attached to the support ring 122. Instead, the support ring 122 has a pattern that inherently provides enhanced support for the attached expandable membrane when used in the expandable distal tip of the suction catheter. More specifically, the support ring includes a serpentine ring or a zigzag ring having a width W in the range of 0.1mm to 1mm, preferably 0.3mm to 0.4mm; a gap G between adjacent rings in the range of 0mm to 1mm, preferably 0.05mm to 0.4mm; a crown arranged along the axis separated by a spacing CS in the range of 0.1mm to 1mm, preferably 0.25mm to 0.4mm; and struts diverging from the crown at an angle α in the range of 00 to 90°, preferably 20° to 40°, before expansion.

[0249] Fig. 9CAnother alternative embodiment of the support stent 140 of the present invention is shown, which has a discrete support pad 150 located between the struts 144 of the serpentine radially expandable support ring 142. The struts 144 are connected by crowns 146 in a conventional manner, and adjacent support rings 142 are connected by connecting rods 147. The support pads 150 are attached to the support membrane 152 in the V-shaped area between adjacent struts 144, but are not otherwise attached to the remaining components of the expandable support structure 140. The support pads 150 preferably (but not necessarily) can have a triangular shape that corresponds to the V-shaped area to which they are attached. They can also have other shapes, such as circular, elliptical or other circular shapes.

[0250] Reference now FIG. 10A to FIG. 10G , delivery of an aspiration catheter to a patient's vasculature according to the principles of the present invention will be described. Figure 1 The aspiration catheter 12 shown in FIG. 1 is advanced to the region of the clot C in the patient's blood vessel BV (typically a cerebral vessel), as shown in FIG. Fig. 10A For convenience, only the expandable distal tip 18 of the aspiration catheter 12 is shown. Fig. 10B and Fig. 10C As shown, the balloon 26 of the distal extension catheter 14 is inflated to expand the expandable distal tip 18 of the catheter against the vessel wall. In some cases, the aspiration catheter 12 is first introduced into the vessel BV over a guide wire, and the distal tip extension catheter 14 is introduced after the aspiration catheter is positioned. In other cases, the aspiration catheter 12 and the distal tip extension catheter 14 are introduced together or in series. After the distal tip 18 of the aspiration catheter 12 has been expanded, the distal tip extension catheter 14 is withdrawn, as shown in FIG. Fig. 10D After the clot has been aspirated, the aspiration catheter 12 is withdrawn through the sheath S (or guide catheter), as shown. Fig. 10E As shown, the extended distal tip 18 is retracted (collapsed) for removal, as shown Fig.10F and Figure 10G Alternatively (not shown), the aspiration catheter can be withdrawn until the proximal end of the expandable tip reaches the distal end of the sheath, and then the sheath and aspiration catheter are removed together as a unit.

[0251] Reference now FIG. 11A to FIG. 11D , an alternative construction 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 a support stent 238 and an expandable membrane 240. As previously described, the expandable membrane 240 will typically include an elastic or non-elastic (stretchable) polymer film having a support stent 238 embedded or laminated therein. The support stent 238 will include a metal or metal alloy stent configured for balloon expansion, typically including a wrought metal as described elsewhere herein.

[0252] The support stent 238 includes a plurality of radially expandable circumferential support rings 242. The rings 242 include a U-shaped or other shaped curved or cellular structure including struts 248 connected by crowns 250, wherein adjacent rings 242 are connected end to end in a spiral pattern.

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

[0254] Typically, but not necessarily, the support bracket 238 will be, for example, Fig. 11B and Fig.11D The "expanded" pattern shown is laser cut from a metal alloy tube. The pattern includes a coil support (reinforcement) area 244 that is intended to support at least the proximal portion of the tubular body 222, such as Fig.11A 244 to provide stress relief between the highly flexible distal tip and the less flexible catheter shaft. The length of the coil support 244 may be long enough 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 braided or other forms of reinforcement, such as Figure 1A shown.

[0255] like FIG. 11A to FIG. 11D As shown, the expandable distal tip 218 and support structure 238 of the aspiration catheter 212 are in their non-expanded configuration, which is suitable for introduction through the patient's vasculature to the target clot location. However, once the target clot location is reached, the expandable distal tip 218 and support structure 238 will be expanded by a balloon to engage the clot or the vessel wall adjacent to the clot, as described below with reference to Figure 13A-13G Described in more detail. Fig. 11B As shown, the proximal end of the expandable stent includes an expandable segment and a non-expandable segment on the proximal ring and is attached to an adjacent coil at at least one position (as shown). Alternatively, the end can be attached to an adjacent expandable ring and / or an adjacent non-expandable coil at one or more positions by a connecting rod and / or an attachment point on an adjacent ring or turn. Alternatively, the proximal ring of the expandable stent can be configured as a substantially non-expandable, expandable segment and a segment of a non-expandable structure that is non-expandable on the same ring or is configured to be fully expandable and attached separately to the proximal end.

[0256] like Fig.11DAs best shown in FIG. 1 , the distal end of the support stent 238 includes a terminal 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 last helical turn of the stent 238. The enlarged end 262 is also attached to the tapered end 264 of the terminal ring 260. In this way, a transition is formed between the helical direction of the ring 242 and the "square" distal end face 268 of the support stent 238. This "square" structure eliminates exposure of the free distal end of the ring to the vessel lumen when the aspiration catheter is advanced through the vasculature.

[0257] Fig.11E and Fig.11F are alternative detailed views of the transition region between the expandable support 238 and the fixed diameter coil support region 244 of the aspiration catheter of the present invention. In both cases, the short axial link 246 provides stress relief at the transition between the support 238 and the coil support region 244. Fig.11F In the embodiment, the connection portion 247 between the support bracket 238 and the coil support area 244 is thinned to form an inflection point, thereby enhancing bending.

[0258] Fig.11G A preferred embodiment of the present invention is shown 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 the distal tip radially expands. The axial width is defined by the distance between the crowns 250 (as shown by line 263), wherein the distal tip 258 of each tab-like support structure remains between adjacent struts 248 until the distal tip expands,

[0259] Although it is preferred that the support member 252 remain recessed, as Fig.11H As shown, the distal tip 259 of the cantilever support element of the present invention may also protrude into the gap area outside the line 263, such as Fig.11H Although this configuration is generally less flexible than other similar recessed configurations.

[0260] As shown thus far in this application, exemplary helical support structures are generally composed of a single helically wound serpentine, zigzag, or other ribbon having bends that allow elongation as the associated ring expands radially. In other cases, such as Fig.11I and Fig.11J As shown, support structures 700 and 702 may have two, three, four, or more spirally nested spiral rings. Fig.11I As shown in detail in FIG. 7 , the support structure 700 includes a first spiral nested ring 710 and a second spiral nested ring 712. Fig.11J As specifically shown in FIG. 7 , the support structure 702 includes a first spiral nested ring 720 , a second spiral nested ring 722 , and a third spiral nested ring 724 .

[0261] FIG. 12A to FIG. 12D The FIG. 11A to FIG. 11C The support stent of the expandable distal tip of the suction catheter. The expanded distal tip stent may have a bell shape 238a ( Fig. 12A )、conical 238b( Fig. 12B )、Pear-shaped 238c( Fig. 12C ), round or curved cone 238d ( Fig.12D ), and other variations and combinations of many shapes that taper radially outward in the distal direction.

[0262] Fig.12E Shown is the same as shown in the non-expanded configuration Fig. 12A A support stent similar to the support stent shown in , wherein a reduced diameter tip 238e is connected to a larger diameter distal shaft end 244e to facilitate introduction over a guide wire.

[0263] Figure 13A-13G The invention is shown advancing and deploying in the vasculature of a patient. Figures 11A-11D The expandable distal tip 218 of the aspiration catheter. Fig.13A As shown, the distal tip 218 is advanced to the region of the clot C in the patient's blood vessel BV (typically a cerebral vessel). For convenience, only the support stent 238 of the distal tip 218 of the aspiration catheter is shown (without the expandable membrane 240). Fig. 13B and Fig. 13C As shown, the balloon 226 of the distal extension catheter 214 is inflated to expand the expandable distal tip 218 of the catheter against the vessel wall. Typically, the aspiration catheter is first introduced into the vessel BV over a guide wire, and then the distal tip extension catheter 214 is introduced after the aspiration catheter is positioned. In other cases, the aspiration catheter and the distal tip extension catheter 214 can be introduced together or in series. After the distal tip 218 of the aspiration catheter has been expanded, the distal tip extension catheter 214 is withdrawn, as shown in FIG. Fig.13D After the clot has been aspirated, the aspiration catheter will be withdrawn through the sheath S, as shown. Fig.13E As shown, thereby causing the extended distal tip 218 to be retracted for removal, as shown Fig.13F and Figure 13G shown.

[0264] Fig.14A and Fig. 14B It is shown how the "pitch angle" of a helical stent can be measured. Fig.14A The "deployment" pattern of an exemplary helical stent 300 is shown in its crimped or pre-expanded configuration, while Fig. 14BThe "expansion" pattern of the same spiral stent 300' in its radially expanded configuration is shown. The pitch angle of the pre-expanded stent 300 is measured between the line L1 along the longitudinal axis of the stent and the line L2 drawn parallel to the ring 302 in the stent. The pitch angle α1 of the stent 300 in the pre-expanded or delivery configuration is typically 70° to 89.9° or more typically 80° to 89.9°, preferably 84° to 89.9°, and more preferably 850 to 89°, and most preferably 86° to 88°. For any given stent, the pitch angle α2 will be greater than the pitch angle α1 because the pitch angle increases as the stent expands radially, approaching 90° when the stent is fully expanded.

[0265] Figure 14C-14E Distal tip support stents with different pitch angles are shown. Support stent 306 is shown having a pitch angle of 87° in its pre-expanded configuration. Support stent 308 is shown having a pitch angle of 86° in its pre-expanded configuration. Support stent 309 is shown having a pitch angle of 85° in its pre-expanded configuration.

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

[0267] Fig.15D and Fig.15E are side and perspective views of a stent 330 having a helically arranged radially expandable rings 332 having a repeating omega-shaped cell pattern.

[0268] Fig.16 The invention shows how the faceted outer surface of the radially expandable distal tip region of the aspiration catheter of the present invention approaches a circular outer edge (achieving enhanced "roundness"). A cross-sectional view of an exemplary radially expandable distal tip region 340 is shown in a pre-expanded configuration (340) and a radially expanded configuration (340'). A circumferential expansion ring 342 is embedded in a polymer film 344 so that the outer surface of the radially expandable distal tip region forms a number of relatively flat facets 346 between the struts 348 of the stent 342.

[0269] In its pre-expanded structure 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, and wherein the length of the first radius r2 is 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, sometimes 200% or less radial expansion), the radially expandable distal tip region has a first radius R1 from the axial centerline C of the ring to the circumferential center of each strut 348 and a second radius r1 from the axial centerline C of the ring to the circumferential edge of each facet 346, and wherein the length of the first radius is 75% to 99%, preferably 97% to 99%, typically 98% to 99%, more typically 98.5% of the length of the second radius. The roundness in the expanded configuration is preferably greater than 97%, more preferably greater than 98%, and most preferably greater than 98.5%.

[0271] Fig.17 Various features that may be used to construct the structure of the helical radially expandable distal tip ring of the present invention are identified, and their values ​​are shown in Table 1 below.

[0272] Table 1: Characteristics of helical loop patterns

[0273]

[0274]

[0275] 18A to 18C 360 are side, perspective, and “expanded” views of an expandable stent 360 that includes a plurality of laterally oriented, axially linked expandable rings 362 connected by axial links 364 .

[0276] Fig.19 Various features that can be used to construct an expandable stent structure including a plurality of transversely oriented, axially linked expandable rings such as Figures 18A-18C The expandable ring shown in the figure has the following values ​​as shown in Table 2

[0277] Table 2: Characteristics of axially linked ring patterns

[0278]

[0279]

[0280] Fig. 20A and Fig. 20Bis a side and "deployed" view of an expandable stent 380 comprising a plurality of parallel, axially linked expandable rings 382 connected by axial links 384 inclined at an acute pitch angle α3 relative to the longitudinal axis of the stent.

[0281] Fig.21 is an "expanded" view of an expandable stent 390 having segments 392 and 394 with cells aligned in phase and out of phase, respectively.

[0282] Fig. 22 is an “expanded” view of an expandable stent 400 , which includes a plurality of rings 402 with gaps 404 of varying lengths therebetween.

[0283] Fig.23A is an "unfolded" view of an expandable stent 500 that includes a plurality of rings 502 arranged in a spiral pattern with gaps 504 between the rings 502. The rings 502 are "smooth," i.e., linear and without bends and curves in the unfolded pattern. Fig. 23B As shown, the rings 502 will each have a serpentine pattern. Fig. 23B 5. A simple serpentine pattern including struts 506 connected by crowns 508 is shown in FIG. 5, but ring 502 may include any cell pattern described herein or otherwise known in the art.

[0284] FIG. 23C to FIG. 23E yes Fig.23A A rotated side view of the expandable stent 500. Fig.23D The view of the bracket 500 shown in FIG. Fig.23C The view in is rotated 90° in the first rotation direction, while Fig.23E The view shown in is rotated 900 in the opposite rotational direction. Because the ring 502 of the stent 500 is "smooth", ie, has no bends, the side view does not change as the stent is rotated about its longitudinal axis.

[0285] Fig.24A FIG. 5 is an “unrolled” view of an expandable stent 520 including a plurality of rings 522 arranged in a spiral pattern with gaps 524 between the plurality of rings 522, wherein a single ring has a first curved shape in the unrolled pattern. The single ring 522 is non-linear and includes two curved or bent regions 532, one of which spans the joint ends, e.g., 534a and 534b, when the stent is rolled up. As shown in the detailed view Fig. 24B As shown, the rings 522 will each have a serpentine pattern. Fig. 24BA simple serpentine pattern including struts 526 connected by crowns 528 is shown in FIG. 5 , but rings 522 may include any cell pattern described herein or otherwise known in the art.

[0286] FIG. 24C to FIG. 24E yes Fig.24A A rotated side view of the expandable support 520. Fig.24D The view of the bracket 520 shown in FIG. Fig.24C The view in is rotated 90° in the first rotation direction, while Fig.24E The view shown in FIG. 5 is rotated 900 in the opposite rotational direction. The curve 532 in the rings 522 of the bracket 520 causes the observed tilt of each ring 522 to change from Fig.24D The rightward tilt shown in Fig.24E The one shown in Figure 1 is tilted to the left.

[0287] Fig.25A 540, which includes a plurality of rings 542 arranged in a spiral pattern with gaps 544 between the plurality of rings 542, wherein a single ring has a second curved shape in the expanded pattern. The single ring 542 is non-linear and includes three curved or bent regions 552 (one of which spans the connecting ends 554a and 554b when the stent is rolled up). As shown in the detailed view Fig.25B As shown, the rings 542 will each have a serpentine pattern. Fig.25B A simple serpentine pattern including struts 546 connected by crowns 548 is shown in FIG. 5 , but rings 542 may include any cell pattern described herein or otherwise known in the art.

[0288] FIG. 25C to FIG. 25E yes Fig.25A A rotated side view of the expandable support 540. Fig.25D The view of the bracket 540 shown in FIG. Fig.25C The view in is rotated 90° in the first rotation direction, while Fig.25E The view shown in FIG. 5 is rotated 90° in the opposite rotational direction. The curves 552 in the rings 542 of the stent 540 cause the observed tilt of each ring 542 to shift forward and backward as the stent is rotated about its longitudinal axis, as can be seen by comparing Fig.25C , Fig.25D and Fig.25E As can be seen in the image.

[0289] Fig.26 is an “expanded” view of an annular pattern including rings 580 having S-shaped expandable elements 582 connected by non-expandable circumferential links 584 shown prior to expansion.

[0290] Fig. 27is an "unrolled" view of an annular pattern including loops 590 formed from wire bent in a serpentine pattern with an integrated cantilever support element 592 formed from tight U-shaped turns that are glued, welded, fused or otherwise held together to prevent separation.

[0291] Fig.28A and Fig.28B is an "expanded" view of a ring pattern including a closed cell box ring 600 shown in its non-expanded configuration and in its expanded configuration, respectively. The box 602 in each ring is Fig.28A The rectangular non-expanded shape shown in FIG. has a circumferential extension of Fig.28B The generally hexagonal elongated shape shown. This elongation allows each ring to expand radially in response to the opening force provided by a balloon or other deployment tool.

[0292] Fig.29A and Fig.29B is an "expanded" view of a ring 610 including a closed cell box 612 shown in its non-expanded and expanded configurations, respectively. Fig.28A and Fig.28B 600 shown in FIG. 6A , except that ring 610 further includes cantilever support elements 614 that are in a non-expanded configuration ( Fig.29A ) is recessed between circumferentially adjacent box elements 612 attached to circumferential links 616. Cantilever support elements 614 are retained in the space between adjacent expansion boxes to provide further support for the surrounding membrane (not shown) after the ring is radially expanded, such as Fig.29B shown.

[0293] Fig. 30A and Fig. 30B 620, which includes an alternative closed cell box formed by side members 622 and cross members 624. When the ring is in the non-expanded configuration, the side members are initially formed into a U-shape, such as Fig. 30A As the ring is radially expanded, the U-shape elongates, as shown in Fig. 30B shown.

[0294] FIG. 31A to FIG. 31C An exemplary method for embedding a radially expandable support stent 630 in a polymer film 640 (one or more films formed of the same or different materials) is shown. The support stent 630 has a serpentine pattern with struts 632 having gaps 634 between the struts 632, such as Fig.31A The support stent 630 may be embedded in the polymer film 640 by first placing sheets 636 and 638 of the desired polymer or polymers on the outer and inner surfaces of the ring 630, as shown. Fig.31BBy applying heat and pressure to the polymer sheet, the polymer will flow into the gap 634 to form a continuous polymer film matrix 640 having an outer surface 642 and an inner surface 644, respectively, as shown in FIG. Fig.31C shown.

[0295] Fig.32 6 shows a distal tip including a stent 630 and a polymer film matrix 640 in its radially expanded configuration. The polymer matrix 640 has elasticity, allowing it to stretch and thin as the distal tip expands. Although the polymer film will normally apply a radial closing force, the expanded support stent 630 will have sufficient hoop strength (compression resistance) to hold the distal tip open against the elastic force of the polymer film and the vacuum applied during clot aspiration.

[0296] Although certain aspects or examples of the present disclosure have been described in detail, all or part of the changes and modifications and combinations in these aspects and examples are within the scope of the present invention and are obvious to those skilled in the art, including aspects, embodiments or examples that 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, although many changes have been shown and described in different details, other modifications within the scope of the present disclosure are obvious to those skilled in the art based on the present disclosure. It is also contemplated that various combinations or sub-combinations can be made to the specific features and aspects of the aspects, embodiments and / or examples, and the various combinations or sub-combinations still fall within the scope of the present disclosure. Therefore, it should be understood that the various features and aspects of the disclosed embodiments can be combined or replaced with each other to form different modes or examples of the present disclosure. Therefore, the scope of the present disclosure disclosed herein should not be limited by the above-mentioned embodiments or examples. For all the above-mentioned embodiments and examples, for example, the steps of any method do not have to be performed in sequence.

Claims

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

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 after expansion of the distal tip, at least some of the free ends of the support elements protrude into the circumferential gap.

4. A catheter according to claims 1 to 3, wherein at least some of the radially expandable circumferential rings include a serpentine or zigzag structure, the serpentine or zigzag structure including struts connected by a crown, wherein the base end of the support element is attached to the inner side of the crown and the free end is arranged between adjacent struts attached to the crown.

5. The catheter of claims 1 to 4, wherein the radially expandable ring is cylindrically arranged in a cylindrical envelope prior to expansion.

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

7. The catheter of claims 1 to 6, wherein the diameter of the distal tip prior to expansion is equal to or smaller than the diameter of the tubular catheter body.

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

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

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

12. The catheter of claims 1 to 11, wherein at least some of the support elements extend from the radially expandable ring into the circumferential gap in the axial and / or circumferential direction.

13. The catheter according to claims 1 to 12, wherein at least some of the support elements extend from the radially expandable ring into adjacent gaps between two struts in the axial and / or circumferential direction.

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

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

16. The catheter according to claim 15, wherein the open cells are selected from the group consisting of U-shaped segments, V-shaped segments, and Shape element.

17. The catheter of claims 14 to 16, wherein at least some of the expandable cells are closed cells. The catheter of claim 17 , wherein the enclosed unit is a box-shaped segment.

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

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

21. The catheter of claims 1 to 20, wherein at least some of the support elements on at least some adjacent expandable rings extend in an axial and / or circumferential direction, wherein each of the at least some support elements is contained within a unit space on the ring.

22. A catheter according to claims 1 to 20, wherein at least some of the support elements are on at least some adjacent expandable rings, wherein in a patterned or delivered stent structure, each support element is contained within a cell space, filling most or substantially all of the space within the cell space on at least some of the rings.

23. The catheter of claims 1 to 20, wherein at least some adjacent rings have a plurality of strut elements on each ring, wherein in a patterned or delivered stent configuration each strut element is contained within a cell space on the at least some adjacent rings.

24. The catheter of claims 1 to 20, wherein at least some adjacent expandable rings, wherein each ring comprises a plurality of expandable cells, wherein most or all of the cells comprise at least one support element.

25. The catheter of claims 1 to 20, wherein at least some adjacent expandable rings, each ring comprises a plurality of expandable units, wherein at least half, a majority of the units, or all of the units comprise at least one support element, and wherein the support elements have a symmetrical pattern on at least some of the rings or along the length of the stent.

26. A catheter according to claims 1 to 20, wherein at least some adjacent rings, each ring comprises a plurality of expandable units, wherein at least half, a majority of the units, or all of the units contain at least one support element, wherein the average width or width of the support element segment connecting the base end to the free end is equal to or greater than the average width or width of adjacent struts or adjacent crowns on the ring.

27. The catheter of claims 1 to 20, wherein at least some adjacent expandable rings, each ring comprises a plurality of expandable units, wherein at least half, a majority or all of the units comprise at least one support element, and wherein the support elements have substantially the same shape, size and / or configuration on at least some of the rings or along the length of the stent.

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

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

30. The catheter of claims 1 to 29, wherein at least some of the support elements include an expanded tip at the free end.

31. The catheter of claims 1 to 30, wherein at least some of the support elements branch into two or more segments in a direction toward the free end.

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

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

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

35. The catheter of claim 34, wherein at least some of the adjacent rings in the helical arrangement include non-linear portions.

36. The catheter of claim 35, wherein all of the adjacent rings in the helical arrangement are free of non-linear portions.

37. The catheter of claim 35, wherein at least some adjacent rings in the helical pattern are connected 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 links or attachment points therebetween.

39. The catheter of claims 1 to 38, wherein the membrane comprises an elastic membrane.

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 to 41, wherein the membrane comprises one or more elastomers.

43. The catheter of claim 42, wherein the one or more elastomers are selected from NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU455-50A, NeuSoft TM 596-50A, NeuSoft NEU455-55A, NeuSoft NEU 455-60A, NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A, Tecoflex TT-18095A, Elastollan S 50A 15SPF, Elastollan S 60A 10W, Elastollan S60A 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 TPU70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex00–30, Ecoflex 00–20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, chronoprene, chronothane, chronosil, combinations thereof, etc.

44. The catheter of claims 39 to 43, wherein the support structure is embedded in the elastomer by application of heat and / or pressure.

45. The catheter of claims 39 to 44, wherein the elastic membrane has isotropic properties.

46. ​​The catheter of claims 39 to 44, wherein the elastic membrane has anisotropic properties, wherein the membrane is more elastic in a circumferential direction than in an axial direction.

47. The catheter of claims 1 to 38, wherein the membrane comprises a non-elastic membrane.

48. A catheter according to claim 47, wherein the one or more expandable membranes include a material selected from one or more polymers such as: polyethylene, such as LDPE, HDPE, Ultra HMWPE, etc.; Pebax, such as Pebax3533, Pebax 4033, Pebax4533, Pebax 5533, Pebax 7233, etc.; Nylon, such as Nylon 12, Nylon 6 / 6 or Nylon 6; Polyurethane, such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMart Ultra TPU 72D; fluoropolymers, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-hexafluoropropylene), fluorinated ethylene propylene, polychlorotrifluoroethylene, etc.; or other polymers.

49. The catheter of claims 1 to 48, wherein the expandable membrane is formed by heat shrinking onto the expandable stent.

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

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 to 51, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter stent comprising a helical coil.

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

54. A catheter as described in Claim 53, wherein the helical coil comprises a plurality of turns connected end to end in a helical pattern.

55. The catheter of claims 52 to 54, wherein distal turns of the helical coil are connected to proximal turns of the helical expandable support structure by one or more links and / or attachment points.

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

58. A catheter as described in claims 4 to 57, wherein the base ends of at least some of the plurality of support elements are attached to struts.

59. The catheter of claims 4 to 57, wherein the base ends of at least some of the plurality of support elements are attached to the crown.

60. A method for aspirating a clot from the vasculature of a patient, the method comprising: positioning a distal tip of the expandable support structure of the catheter of claims 1 to 60 in the vasculature of the patient at the area of ​​the clot; extending the distal tip to engage a clot; as well as Negative pressure is applied to the proximal end of the lumen in the catheter body to draw the clot into the central channel of the expanded distal tip.

61. A catheter comprising: a tubular catheter body having a proximal end, a distal end, and a lumen extending between the proximal end and the distal end; as well as an expandable support structure at the distal end of the tubular catheter body and having a central channel connected to the lumen of the tubular catheter body, wherein the expandable support structure comprises an expandable membrane and a support stent configured to radially expand the expandable membrane, wherein the stent comprises: (a) a plurality of radially expandable rings arranged along a longitudinal axis, wherein at least some of the radially expandable rings include expandable units that are circumferentially elongated to accommodate radial expansion; as well as (b) a plurality of support elements attached to at least one location on at least some of the expandable cells on the radially expandable ring or to at least one location near at least some of the expandable cells on the radially expandable ring, wherein at least some of the support elements extend into, from, or between the expandable cells to support the membrane when the membrane expands from a delivery configuration to an expanded configuration.

62. The catheter of claim 61, wherein the expandable unit comprises struts connected by crowns to form a V-shape, a U-shape, a Shaped or box-shaped expandable element.

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

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

65. The catheter of claim 64, wherein at least some of the adjacent loops in the helical pattern include non-linear portions.

66. The catheter of claim 64, wherein all of the adjacent rings in the helical arrangement are free of non-linear portions.

67. The catheter of claims 61 to 66, wherein the radially expandable ring is cylindrically arranged in a cylindrical envelope prior to expansion.

68. The catheter of Claim 66, wherein the diameter of the cylindrical cuff prior to expansion is equal to or less than the diameter of the tubular catheter body.

69. The catheter of claim 67 or 68, wherein the support element is located within the cylindrical envelope.

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

71. The catheter of claims 61 to 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 to 70, wherein the expandable support structure is configured to self-expand when released from a radial constraint.

73. The catheter of claims 61 to 72, wherein at least some of the support elements extend in a circumferential direction from the radially expandable ring into the cell space.

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

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

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

77. The catheter of claims 61 to 76, wherein at least some of the support elements include an expanded tip at the free end.

78. The catheter of claims 61 to 77, wherein at least some of the support elements branch into two or more segments in a direction toward the free end.

79. The catheter of claims 61 to 78, wherein at least some of the support elements have two or more segments attached to the struts or crowns and joined together in the cell spaces.

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

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

82. The catheter of claim 81, wherein the one or more elastomers are selected from NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft TM 596-50A, NeuSoft NEU455-55A, NeuSoft NEU 455-60A, NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A, Tecoflex TT-18095A, Elastollan S 50A 15SPF, Elastollan S 60A 10W, Elastollan S60A 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 TPU70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex00–30, Ecoflex 00–20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax 3033, chronoprene, chronothane, chronosil, combinations thereof, etc.

83. The catheter of claims 80 to 82, wherein the elastic membrane has isotropic properties.

84. The catheter of claims 80 to 82, wherein the elastic membrane has anisotropic properties, wherein the membrane is more elastic in a circumferential direction than in an axial direction.

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

86. A catheter according to claim 85, wherein the non-elastic membrane comprises a material selected from one or more polymers such as: polyethylene, such as LDPE, HDPE, Ultra HMWPE, etc.; Pebax, such as Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, etc.; nylon, such as nylon 12, nylon 6 / 6 or nylon 6; polyurethane, such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMart Ultra TPU 72D; fluoropolymers, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-hexafluoropropylene), fluorinated ethylene propylene, polychlorotrifluoroethylene, etc.; or other polymers.

87. The catheter of claims 61 to 86, wherein the expandable membrane is formed by heat shrinking onto the expandable stent.

88. The catheter of claims 61 to 86, wherein the expandable membrane is formed by lamination between two layers of said elastomer.

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

90. The catheter of claims 61 to 89, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter stent.

91. The catheter of claim 90, wherein the catheter stent is continuous with the stent in the expandable structure.

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

93. A method for aspirating a clot from the vasculature of a patient, the method comprising: positioning a distal tip of the expandable support structure of the catheter of claims 61 to 92 in the vasculature of the patient at the area of ​​the clot; extending the distal tip to engage clot adjacent the clot region; as well as Negative pressure is applied to the proximal end of the lumen in the catheter body to draw the clot into the central channel of the expanded expandable structure.

94. A suction catheter comprising: a tubular catheter body having a proximal end, a distal end, and a lumen extending along a longitudinal axis; as well as a distal tip having a proximal end attached to the distal end of the tubular catheter body and a central passageway longitudinally connected to the lumen of the tubular catheter body, wherein the distal tip is adapted to expand from a radially contracted configuration to a radially expanded configuration in response to a radially outward expansion force applied within the distal tip; wherein the distal tip comprises an expandable membrane and an expandable support member; and wherein the expandable support member comprises a plurality of rings spaced apart along the longitudinal axis with circumferential gaps therebetween, and wherein at least some of the rings comprise a wrought metal or metal alloy configured to plastically deform in response to the radially outward expansion force applied within the distal tip to circumferentially expand the stent.

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

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

97. The catheter of claims 94 to 96, wherein the support member has a curled delivery configuration (delivery configuration) and an expanded deployed configuration.

98. The catheter of claims 94 to 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. The catheter of claims 94 to 98, wherein the distal tip is configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to the radially outward expansion force applied within at least a portion of the distal tip.

100. The catheter of claims 94 to 99, wherein the distal tip is configured to expand from an initial cylindrical shape to an enlarged conical configuration in response to the radially outward expansion force applied within at least a portion of the distal tip.

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

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

103. The catheter of claim 102, wherein the bending resistance is measured by the 3-point flex test described herein.

104. The catheter of claim 102 or 103, wherein the collapse pressure is applied at the proximal end of the catheter body lumen and the central channel of the distal tip is blocked.

105. The catheter according to any one of claims 94 to 104, wherein the distal tip has a kink-free minimum bending radius of 5 mm, preferably 3 mm, more preferably 2 mm in its radially contracted structure, and the distal tip has a kink-free minimum bending radius of 10 mm, preferably 6 mm, more preferably 2 mm in its radially expanded structure.

106. The catheter according to any one of claims 94 to 105, wherein the ring of the support member spans a length measured in the longitudinal direction in the range of 0.2 mm to 200 mm, preferably in the range of 1 mm to 40 mm, more preferably in the range of 10 mm to 40 mm.

107. The catheter of any one of claims 94 to 106, wherein the support member consists of 5 to 100 rings arranged in the longitudinal direction.

108. A catheter according to any one of claims 94 to 107, wherein when the support member is in the delivery structure, the gap between adjacent rings has a length measured in the longitudinal direction ranging from 0.02 mm to 0.3 mm, preferably 0.05 mm to 0.2 mm, more preferably 0.05 mm to 0.15 mm.

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

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

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

112. The catheter of claim 111, wherein at least some of the bends include U-shaped bends, V-shaped bends, and Shaped bend, box-shaped bend.

113. A catheter according to claim 111 or 112, wherein at least some of the rings include 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, and more typically 4 to 10 bends per mm of circumferential length.

114. The catheter of any one of claims 94 to 113, wherein at least some of the adjacent loops are continuously connected end to end in a spiral pattern.

115. The catheter of claim 114, wherein at least some of the adjacent loops in the helical pattern include non-linear portions.

116. The catheter of claim 114, wherein all of said adjacent rings in said spiral pattern are free of non-linear portions.

117. The catheter of any one of claims 94 to 116, wherein at least some of the adjacent rings are connected by axial connecting rods.

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

119. The catheter of claim 117, wherein at least some of the adjacent rings are not continuously formed and are connected to adjacent rings only by one or more axial links.

120. A catheter according to any one of claims 94 to 119, wherein the wrought metal comprises a metal or metal alloy selected from the following metals or metal alloys: cobalt chromium, such as L-605, MP35N, Stellite 6B, ASTM F1537 / F799 Alloy 1, ASTM F1537 / F799 Alloy 2; stainless steel, such as 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L and 420S; tantalum; niobium; tungsten; molybdenum; platinum; platinum alloys, such as platinum iridium, platinum chromium, platinum cobalt chromium; magnesium; magnesium alloys, such as Mg-3A1-1Z, Mg-Zn-Se and Mg-Zn-Cu; zinc, etc. or others.

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

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

123. The catheter of claim 122, wherein the one or more elastomers are selected from NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft TM 596-50A, NeuSoft NEU455-55A, NeuSoft NEU 455-60A, NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A, Tecoflex TT-18095A, Elastollan S 50A 15SPF, Elastollan S 60A 10W, Elastollan S60A 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 TPU70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex00–30, Ecoflex 00–20, Ecoflex5A, Dragon Skin 20, Pebax 2533, Pebax 3033, chronoprene, chronothane, chronosil, combinations thereof, etc.

124. The catheter of claims 121 to 123, wherein the elastic membrane has isotropic properties.

125. The catheter of claims 121 to 123, wherein the elastic membrane has anisotropic properties, wherein the membrane is more elastic in a circumferential direction than in an axial direction.

126. The catheter of any one of claims 94 to 125, wherein the tubular membrane comprises a non-elastic membrane.

127. A catheter according to claim 126, wherein the non-elastic membrane comprises a material selected from one or more polymers such as: polyethylene, such as LDPE, HDPE, Ultra HMWPE, etc.; Pebax, such as Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, etc.; nylon, such as nylon 12, nylon 6 / 6 or nylon 6; polyurethane, such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMartUltra TPU 72D; fluoropolymers, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-hexafluoropropylene), fluorinated ethylene propylene, polychlorotrifluoroethylene, etc.; or other polymers.

128. A catheter according to claims 126 or 127, wherein the non-elastic membrane is configured to plastically deform as the support member expands.

129. The catheter of claims 126-127, wherein the membrane is configured to unfold as the support member expands.

130. The catheter of claims 94-129, wherein the distal tip is formed by heat shrinking the tubular film onto the expandable support member.

131. The catheter of claims 94 to 129, wherein the distal tip is formed by laminating the expandable support member between layers of the tubular film.

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

133. The catheter of claims 94 to 132, wherein the membrane consists of at least two membrane segments.

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

135. The catheter of claim 134, wherein the at least two film segments comprise at least two types of materials.

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

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

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

139. The catheter of claims 94 to 138, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter support member.

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

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

142. The catheter of claim 140, wherein the catheter support member and the expandable support member are formed by one or more bend wires, each of which spans at least a portion of the catheter support member and the expandable support member.

143. The catheter of claims 94 to 142, further comprising a plurality of support elements, each support element having a base end and a free end, wherein the base end is attached to one of the radially expandable rings and the free end extends into an adjacent circumferential gap.

144. A catheter according to claim 143, wherein at least some of the plurality of rings include struts connected by bends.

145. A catheter according to claim 144, wherein the base ends of at least some of the plurality of support elements are attached to struts.

146. A catheter according to claim 144, wherein the base ends of at least some of the plurality of support elements are attached to the bend.

147. The catheter of claim 144, wherein base ends of at least some of the plurality of support elements are attached to an inner surface of the ring.

148. The catheter of claim 143, wherein base ends of at least some of the plurality of support elements are attached to an outer surface of the ring.

149. The catheter of any one of claims 143 to 148, wherein at least some of the plurality of support elements have a constant width across a distal portion thereof.

150. The catheter of any one of claims 143 to 148, wherein at least some of the plurality of support elements have variable widths at distal portions thereof.

151. The catheter of any one of claims 143 to 150, wherein at least some of the plurality of support elements have distal tips extending into the adjacent circumferential gaps.

152. The catheter of any one of claims 143 to 150, wherein at least some of the plurality of support elements have distal tips that terminate flush with the bends joining the struts.

153. The catheter of any one of claims 143 to 150, wherein at least some of the plurality of support elements have distal tips that are recessed between adjacent bends joining the struts.

154. A suction catheter comprising: a tubular catheter body having a proximal end, a distal end, and a lumen extending along a longitudinal axis; as well as a distal tip having a proximal end attached to the distal end of the tubular catheter body and a central passageway longitudinally connected to the lumen of the tubular catheter body, wherein the distal tip is adapted to expand from a radially contracted configuration to a radially expanded configuration in response to a radially outward expansion force applied within the distal tip; wherein the distal tip comprises a tubular membrane and an expandable support member; and wherein the expandable support member comprises a plurality of rings spaced apart along the longitudinal axis with circumferential gaps therebetween, and wherein at least some of the rings comprise circumferentially adjacent cells having bends configured to straighten in response to a radially outward expansion force applied within the distal tip to permit expansion of the rings.

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. A catheter according to claim 154 or 155, wherein the unit comprises struts connected by bends.

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

158. A catheter according to any one of claims 154 to 157, wherein in the support member in a delivery configuration, the circumferentially adjacent units have a peak-to-peak amplitude (width in the longitudinal direction) 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. The catheter of any one of claims 154 to 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 according to claims 154 to 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, wherein the ratio ranges from 2 per mm to 15 per mm, preferably from 3 per mm to 12 per mm, more preferably from 4 per mm to 12 per mm, and most preferably from 5 per mm to 12 per mm.

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

162. A catheter according to claim 161, wherein the ratio varies over at least a portion of the support member.

163. The catheter of any one of claims 154 to 162, wherein in the delivery configuration, the ring spans a length measured in the longitudinal direction in the range of 0.2 mm to 400 mm.

164. The catheter of any one of claims 154 to 163, wherein in the delivery configuration the gaps between adjacent rings are in the range of 0.025 mm to 0.35 mm measured in the longitudinal direction.

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

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

167. A catheter according to claim 166, wherein at least some of the adjacent rings in the spiral pattern include non-linear portions.

168. A catheter according to claim 166, wherein all of the adjacent rings in the spiral pattern are free of non-linear portions.

169. The catheter of claims 154 to 168, wherein in the delivery structure, adjacent rings are joined at an acute pitch angle relative to the longitudinal axis, the acute pitch angle ranging from 80° to 89.9°, preferably 85° to 89°, and more preferably 86° to 88°.

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 to 171, wherein at least some of the adjacent rings are connected by axial links or attachment points.

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

174. A catheter according to claim 173, wherein the wrought metal comprises a metal or metal alloy selected from the following: cobalt chromium, such as L-605, MP35N, Stellite 6B, ASTM F1537 / F799 alloy 1, ASTM F1537 / F799 alloy 2; stainless steel, such as 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L and 420S; tantalum; niobium; tungsten; molybdenum; platinum; platinum-iridium alloys, such as Pt-10Ir, Pt-20Ir and Pt-30Ir; nitinol; superelastic nitinol; magnesium; magnesium alloys, such as Mg-3A1-1Z, Mg-Zn-Se and Mg-Zn-Cu; zinc, etc.

175. A catheter according to claim 174, wherein the wrought metal comprises a molybdenum alloy, such as a molybdenum-rhenium alloy comprising 90% to 100% molybdenum and rhenium.

176. A catheter according to claim 175, wherein the molybdenum-rhenium alloy further includes 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. The catheter of any one of claims 154 to 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. The catheter of claims 154 to 176, wherein the distal tip is configured to expand from an initial cylindrical shape to an enlarged cylindrical configuration in response to a radially outward expansion force applied within the distal tip.

179. The catheter of claims 154 to 176, wherein 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 the distal tip.

180. The catheter of claims 154 to 179, wherein the circumferentially adjacent cells in at least some of the rings in the distal tip have flat outer surfaces defining facets in a polygonal structure.

181. A catheter according to claim 180, wherein the ring has 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, and wherein the length of the first radius is 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. The catheter according to any one of claims 154 to 181, wherein the length of the tubular catheter body from the proximal end to the distal end is in the range of 50 cm to 200 cm, the outer diameter of the tubular catheter body is in the range of 0.5 mm to 30 mm, and the inner cavity diameter of the tubular catheter body is in the range of 0.25 mm to 25 mm.

183. The catheter of any one of claims 154 to 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 catheter of claim 184, wherein the one or more elastomers are selected from NeuSoft UR862A, NeuSoft UR852A, NeuSoft UR842A, NeuSoft NEU 455-50A, NeuSoft TM 596-50A, NeuSoft NEU455-55A, NeuSoft NEU 455-60A, NeuSoft NEU 455-65A, Tecothane AR-62A, Tecoflex EG80A, Tecoflex EG 85A, Tecoflex EG-93A, Tecoflex TT-1074A, Tecoflex TT-1085A, Tecoflex TT-18095A, Elastollan S 50A 15SPF, Elastollan S 60A 10W, Elastollan S60A 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 TPU70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU 95A, Ecoflex00–30, Ecoflex 00–20, Ecoflex5A, Dragon Skin 20, Pebax 2533, Pebax 3033, chronoprene, chronothane, chronosil, combinations thereof, etc.

186. The catheter of claims 183 to 185, wherein the elastic membrane has isotropic properties.

187. The catheter of claims 183 to 186, wherein the elastic membrane has anisotropic properties, wherein the membrane is more elastic in a circumferential direction than in an axial direction.

188. The catheter of any one of claims 154 to 187, wherein the tubular membrane comprises a non-elastic membrane.

189. A catheter according to claim 188, wherein the non-elastic membrane comprises a material selected from one or more polymers such as: polyethylene, such as LDPE, HDPE, Ultra HMWPE, etc.; Pebax, such as Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, etc.; nylon, such as nylon 12, nylon 6 / 6 or nylon 6; polyurethane, such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMartUltra TPU 72D; fluoropolymers, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-hexafluoropropylene), fluorinated ethylene propylene, polychlorotrifluoroethylene, etc.; or other polymers.

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

191. The catheter of claims 188 to 190, wherein the membrane is configured to unfold as the support member expands.

192. The catheter of claims 154 to 191, wherein the distal tip is formed by heat shrinking the tubular film onto the expandable support member.

193. The catheter of claims 154 to 191, wherein the distal tip is formed by laminating the expandable support member between layers of the tubular film.

194. A catheter according to claim 193, wherein the layers are bonded to each other so that a seal exists between the layers.

195. The catheter of claims 154 to 194, wherein the tubular catheter body is reinforced over at least a portion of its length by a catheter support member.

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

197. The catheter of claims 154 to 196, further comprising a plurality of support elements, each support element having a base end and a free end, wherein the base end is attached to one of the radially expandable rings and the free end extends into an adjacent axial and / or circumferential gap.

198. A catheter according to claim 197, wherein at least some of the plurality of rings include struts connected by bends.

199. A catheter according to claim 198, wherein the base ends of at least some of the plurality of support elements are attached to struts.

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

201. The catheter of claim 197, wherein base ends of at least some of the plurality of support elements are attached to an inner surface of the ring.

202. The catheter of claim 197, wherein base ends of at least some of the plurality of support elements are attached to an outer surface of the ring.

203. The catheter of any one of claims 197 to 202, wherein at least some of the plurality of support elements have a constant width across a distal portion thereof.

204. The catheter of any one of claims 197 to 202, wherein at least some of the plurality of support elements have variable widths at distal portions thereof.

205. The catheter of any one of claims 197 to 204, wherein at least some of the plurality of support elements have distal tips extending into the adjacent circumferential gaps.

206. The catheter of any one of claims 197 to 204, wherein at least some of the plurality of support elements have distal tips that terminate flush with the bends joining the struts.

207. The catheter of any one of claims 197 to 204, wherein at least some of the plurality of support elements have distal tips that are recessed between adjacent bends joining the struts.

208. A method for aspirating a clot from the vasculature of a patient, the method comprising: positioning a distal tip of the aspiration catheter of claims 154 to 208 in the vasculature of the patient at the area of ​​the clot; expanding the distal tip to its radially expanded configuration to engage a vessel wall proximate the clot region; as well as Negative pressure is applied to the proximal end of the lumen in the catheter body to draw the clot into the central channel of the expanded expandable structure.

209. A method according to claim 208, wherein a portion of the expandable support member remains at least partially unexpanded after another portion of the expandable support member is expanded.

210. 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 successive helical turns disposed along a longitudinal axis, the expandable coil comprising undulating bends and struts with gaps between the successive turns, wherein the successive turns are inclined at an acute pitch angle relative to the longitudinal axis; as well as A sheath is disposed around the expandable coil.

211. The catheter of claim 210, wherein at least some of the adjacent rings in the helical arrangement comprise non-linear portions.

212. The catheter of claim 210, wherein all of the adjacent rings in the helical arrangement are free of non-linear portions.

213. The aspiration catheter of claims 210 to 212, wherein the expandable coil is configured to expand via an expandable support structure that radially expands within the interior of the expandable coil.

214. An aspiration catheter according to claim 213, wherein the expandable coil is balloon expandable.

215. The aspiration catheter of any one of claims 210 to 214, wherein the expandable coil is at least partially formed from a forgeable metal or metal alloy.

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

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

218. An aspiration catheter according to any one of claims 210 to 217, wherein the expandable coil is attached to a reinforcement member or structure in a proximal segment of the catheter body.

219. An aspiration catheter according to claim 218, wherein the expandable coil and the reinforcement member are formed of a continuous wire or tube.

220. The aspiration catheter according to any one of claims 210 to 219, wherein the adjacent rings are connected at an acute pitch angle relative to the longitudinal axis, the acute pitch angle ranging from 85° to 89.9°, preferably 86° to 89°, and more preferably 86° to 88°.

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

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

223. The aspiration catheter of any one of claims 210 to 222, wherein the expandable coil has a curled delivery configuration and an expanded deployment configuration.

224. An aspiration catheter according to any one of claims 210 to 223, wherein the curled delivery structure of the expandable coil has a maximum outer diameter in the range of 0.5 mm to 30 mm, and the expanded deployment structure has a maximum outer diameter in the range of 0.5 mm to 40 mm.

225. An aspiration catheter according to any one of claims 210 to 224, wherein the length of the tubular catheter body from the proximal end to the distal end is in the range of 50 cm to 200 cm, the outer diameter of the tubular catheter body is in the range of 0.5 mm to 30 mm, and the inner cavity diameter of the tubular catheter body is in the range of 0.25 mm to 25 mm.

226. The aspiration catheter according to any one of claims 210 to 225, wherein the expandable coil has a bending resistance lower than 1N, preferably lower than 0.5N, more preferably lower than 0.3N in its initial radially contracted structure, and the expandable coil has a collapse pressure equal to or higher than 0.5atm, preferably equal to or higher than 0.75atm, more preferably equal to or higher than 1atm in its radially expanded structure.

227. An aspiration catheter according to claim 226, wherein the bending resistance is measured by a 3-point flex test, wherein the span length is 13 mm and the maximum deflection is 2.0 mm.

228. The catheter of claim 226 or 227, wherein the collapse pressure is applied at the proximal end of the catheter body lumen and the distal tip of the catheter body lumen is blocked.

229. An aspiration catheter according to any one of claims 210 to 228, wherein the expandable coil has a kink-free minimum bending radius of 5 mm, preferably 3 mm, more preferably 2 mm in its radially contracted structure, and the expandable coil has a kink-free minimum bending radius of 10 mm, preferably 6 mm, more preferably 2 mm in its radially expanded structure.

230. An aspiration catheter according to any one of claims 210 to 229, wherein the continuous turns of the expandable coil span 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, and more preferably in the range of 10 mm to 40 mm.

231. The aspiration catheter of any one of claims 210 to 230, wherein the expandable coil consists of 5 to 725 consecutive helical turns.

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

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

234. 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 to 234, wherein the expandable coil has at least 2 loops per mm length, preferably at least 3 loops per mm length, typically 2 to 5 loops per mm length, and more typically 3 to 5 loops per mm length.

236. An aspiration catheter according to any one of claims 210 to 235, wherein the wrought metal comprises a metal or metal alloy selected from the following: cobalt chromium, such as L-605, MP35N, Stellite 6B, ASTM F1537 / F799 alloy 1, ASTMF1537 / F799 alloy 2; stainless steel, such as 316, 316L, 316LS, 316LVM, 304, 304V, 304L, 304LV, 304LVM, 410, 410L, 410S, 420, 420L and 420S; tantalum; niobium; tungsten; molybdenum; platinum; platinum-iridium alloys, such as Pt-10Ir, Pt-20Ir and Pt-30Ir; nitinol; superelastic nitinol; magnesium; magnesium alloys, such as Mg-3A1-1Z, Mg-Zn-Se and Mg-Zn-Cu; zinc, etc.

237. An aspiration catheter according to claim 236, wherein the wrought metal comprises a molybdenum alloy, such as a molybdenum-rhenium alloy comprising 90% to 100% molybdenum and rhenium.

238. A catheter according to claim 237, wherein the molybdenum-rhenium alloy further includes 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 to 238, wherein the sheath comprises an elastic membrane.

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

241. The aspiration catheter of claim 240, wherein the one or more elastomers are selected from 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, TecoflexTT-1085A, Tecoflex TT-18095A, Elastollan S 50A15SPF, Elastollan S 60A 10W, Elastollan S 60A 10WH, Pellethane2103-70A, Pellethane 70A, Pellethane 2363-80A, Estane 2103-70A, ReZithane RX50A, Texin RXT 70A, Chronoflex C 80A-Q, ChronoflexAL 75A-Q, Chronoflex C 80A-Q, Polyblend 1100-75A, ResMart Ultra TPU 60A, ResMartUltra TPU 70A, ResMart Ultra TPU 85A, ResMart Ultra TPU 90A, ResMart Ultra TPU95A, Ecoflex 00–30, Ecoflex 00–20, Ecoflex 5A, Dragon Skin 20, Pebax 2533, Pebax3033, chronoprene, chronothane, chronosil, combinations thereof, etc.

242. An aspiration catheter according to claims 239 to 241, wherein the elastic membrane has isotropic properties.

243. An aspiration catheter according to claims 239 to 242, wherein the elastic membrane has anisotropic properties, wherein the elasticity of the membrane in the circumferential direction is higher than the elasticity in the axial direction.

244. The aspiration catheter of any one of claims 210 to 243, wherein the sheath comprises a non-elastic membrane.

245. An aspiration catheter according to claim 244, wherein the non-elastic membrane comprises a material selected from one or more polymers such as: polyethylene, such as LDPE, HDPE, Ultra HMWPE, etc.; Pebax, such as Pebax 3533, Pebax 4033, Pebax 4533, Pebax 5533, Pebax 7233, etc.; nylon, such as nylon 12, nylon 6 / 6 or nylon 6; polyurethane, such as Pellethane 2363-55D, Pellethane 2363-65D, ResMart Ultra TPU 64D, ResMart Ultra TPU 72D; fluoropolymers, such as PTFE, poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinylidene fluoride-co-hexafluoropropylene), fluorinated ethylene propylene, polychlorotrifluoroethylene, etc.; or other polymers.

246. An aspiration catheter according to claim 244 or 245, wherein the non-elastic membrane is configured to plastically deform as the coil expands.

247. An aspiration catheter according to claims 244 to 246, wherein the membrane is configured to unfold as the coil expands.

248. The aspiration catheter of claims 210 to 247, wherein the sheath is formed by heat shrinking the sheath over the expandable coil.

249. An aspiration catheter according to claims 210 to 247, wherein the sheath is formed by laminating the expandable coil between layers of the sheath.

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

251. An aspiration catheter according to claims 210 to 250, wherein the sheath is composed of at least two film segments.

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

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

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

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

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

257. An aspiration catheter according to claims 210 to 256, wherein the tubular catheter body is reinforced by a catheter support member over at least a portion of its length.

258. An aspiration catheter according to claim 257, wherein the catheter support member is continuous with the expandable coil.

259. An aspiration catheter as claimed in claim 258, wherein the catheter support member and the expandable coil are patterned from the same tube.

260. An aspiration catheter as described in claim 258, wherein the catheter support member and the expandable support member are formed by one or more bend wires, and each of the one or more bend wires spans at least a portion of the catheter support member and the expandable coil.

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

262. An aspiration catheter according to claim 261, wherein at least some of the plurality of support elements have a constant width at their distal portions.

263. An aspiration catheter according to claim 261, wherein at least some of the plurality of support elements have a variable width at a distal portion thereof.

264. 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 between the proximal end and the distal end; a radially expandable distal tip at the distal end of the tubular catheter body, the radially expandable distal tip having a delivery radius and a central passageway connected to the 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, wherein at least some of the expandable rings comprise cells comprising struts connected by crowns arranged continuously end to end in a spiral pattern; and (b) a membrane covering an outer surface of the expandable support structure; wherein an outer surface area of ​​the membrane supported by the cells has a radius R measured from a longitudinal axis of the expandable support structure; wherein a flat facet in the outer surface of the membrane spanning the gap between circumferentially adjacent cells has a radius r measured from the longitudinal axis of the expandable support structure; and wherein the outer surface of the membrane retains at least 97% of a circularity measured as r / R×100 after the expandable support structure radially expands up to 200% from the delivery radius.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

280. The aspiration catheter of any one of claims 264 to 279, wherein a ratio of an arc length of the bend to an axial length of the strut ranges from 0.2:1 to 2:

1.

281. The aspiration catheter of any one of claims 264 to 279, wherein a ratio of an arc length of the bend to an axial length of the strut ranges from 0.5:1 to 1.5:

1.

282. The aspiration catheter of any one of claims 264 to 279, wherein a ratio of an arc length of the bend to an axial length of the strut ranges from 0.75:1 to 1.25:

1.

283. An aspiration catheter according to any one of claims 264 to 282, wherein at least some of the cells in each ring lack axial connections to axially adjacent rings.

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

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

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

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

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

289. An aspiration catheter according to any one of claims 264 to 288, wherein the distal tip has a collapse pressure (vacuum) equal to or greater than 0.5 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.

290. An aspiration catheter according to any one of claims 264 to 288, wherein the distal tip has a collapse pressure (vacuum) equal to or greater than 0.75 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.

291. An aspiration catheter according to any one of claims 264 to 288, wherein the distal tip has a collapsed 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. An aspiration catheter according to any one of claims 264 to 291, wherein the distal tip is configured to be expanded by a balloon catheter.

293. An aspiration catheter according to claim 292, wherein the distal tip is configured to enable the balloon catheter to expand all or a portion of the axial length of the distal tip.

294. The aspiration catheter according to any one of claims 264 to 293 further includes a plurality of support elements, each support element having a base end and a free end, wherein the base end is attached to one of the radially expandable rings and the free end extends axially and / or circumferentially away from the one of the radially expandable rings.

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

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

298. The catheter of any one of claims 294 to 296, wherein the support element is configured to be positioned within a cylindrical envelope defined by the expandable support structure prior to expansion.

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

300. The catheter of any one of claims 264 to 299, wherein the membrane covers at least an outer surface of the expandable support structure.

301. The catheter of any one of claims 264 to 300, wherein the membrane covers at least an inner surface of the expandable support structure.

302. The catheter of any one of claims 264 to 301, wherein the membrane comprises one or more elastomers.

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

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

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

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

Images