Neurovascular stent

Abstract

A stent (100) having a substantially tubular body is disclosed. In at least one embodiment, the stent (100) provides a skeleton having a plurality of interconnected struts (110) forming a plurality of radial axial rows (120) of radial support units (102) and a plurality of flexible axial rows (125) of flexible support units (104). A plurality of radial axial rows (120) and flexible axial rows (125) are disposed in an alternating pattern along a circumferential axis of the stent (100). The central axis of each radial axial row (120) and flexible axial row (125) is parallel to the longitudinal axis of the stent (100). Each radial axial row (120) is arranged offset relative to each adjacent radial axial row (120) along the longitudinal axis of the stent (100). Each radial support unit (102) is formed by four of the interconnected struts (110) of the skeleton arranged symmetrically along both a longitudinal axis and a circumferential axis of the stent (100).

Description

[0001] Related Applications

[0002] This application claims priority to and has the same filing date as U.S. Provisional Application Serial No. 63 / 351,103, filed on June 10, 2022. This application also claims priority to U.S. Provisional Application Serial No. 63 / 394,376, filed on August 2, 2022. This application also claims priority to U.S. Provisional Application Serial No. 18 / 203,557, filed on May 30, 2023. The contents of the above applications are incorporated herein by reference. Background Art

[0003] The subject matter of this patent application relates generally to the field of intravascular treatment devices, and more particularly to stents for treating a vascular lumen that has been weakened by injury or disease, particularly stents for treating the neurovascular system.

[0004] Applicants hereby incorporate by reference any and all patents and published patent applications cited or referenced in this application.

[0005] As background, vascular diseases, particularly those affecting the neurovascular system, including intracranial atherosclerotic disease (ICAD) and aneurysms, are an important focus for innovation. In 2020, cerebrovascular disease was the fifth leading cause of death in the United States, according to the Centers for Disease Control and Prevention (CDC).

[0006] One possible treatment for neurovascular diseases such as ICAD or aneurysms is to place a stent at the diseased site. The implanted stent supports the weakened or damaged blood vessel, which in turn helps treat the disease in question. For example, a patient with ICAD will have a blocked or partially blocked blood vessel in the neurovascular system, which, if present in a critical part of the anatomy, will reduce or completely interrupt blood flow to the neurovascular system, leading to stroke or death in severe cases. Treatment of ICAD may involve the placement of a particularly small stent that can support the diseased vessel, thereby allowing unrestricted blood flow to distal parts of the vascular system, preventing future damage.

[0007] Current stent designs are made of multiple interconnected metal struts and come in one of two (2) common forms (1): self-expanding and balloon-expandable. Self-expanding stents are made of materials that have shape memory and superelastic properties, such as Nitinol. The diameter of the stent is consistent with the diameter of the vessel to be treated and can vary from 1.5 mm to 4.0 mm or more, depending on the desired anatomical location. Self-expanding stents are typically preloaded into a tube, such as an introducer sheath, which constrains the diameter of the stent until it reaches its final treatment location, at which point the diameter constraint is removed, allowing the stent to expand to its intended diameter, thereby making direct contact with the vessel wall. Balloon-expandable stents follow a similar approach, but instead of being preloaded into a tube, the device is crimped onto a balloon catheter and, after delivery to the target location, plastically deformed via the underlying balloon-expandable stent until the stent fits properly.

[0008] Implanting stents in the neurovasculature presents several challenges, most notably the anatomical challenges of treating small vessels in the neurovasculature, which are notoriously tortuous. Therefore, in order for a stent to be appropriately designed to address the challenges posed by the neurovascular anatomy, the stent must be small and flexible while also providing the radial strength required to treat diseased or damaged vessels. Additionally, since the stent is a permanent implant, the stent must be able to withstand the repetitive stresses typical of the vessel and must be low profile so as not to increase the risk of thrombosis or other side effects of vascular implantation.

[0009] Stent flexibility is very important because the stent is often the least flexible part of a stent delivery system. Not only must the stent be able to traverse the tortuous paths of the anatomy, it must also be able to conform to the geometry of the vessel being treated, which may include bends or torsions. Therefore, a flexible stent is an absolute necessity to be able to treat a wide range of vascular diseases.

[0010] The radial strength of the stent is critical because the role of the stent in the blood vessel is to provide structural support. The radial strength of the stent must be large enough to avoid being damaged by the radial compression forces generated by the pulsating flow of blood and any additional forces applied by the diseased site (such as plaque accumulation). In the case of a self-expanding stent, the radial strength of the stent must also be sufficient to open the blocked blood vessel to its intended diameter, which requires a high level of radial strength relative to the size of the stent.

[0011] The current trend in stent design is to provide stents with the smallest possible profile. It should be understood that, assuming that stent flexibility and stent radial strength properties are fixed, stents with smaller profiles will provide better outcomes for patients. In addition to the advantages of low-profile stents in terms of flexibility and vascular access, low-profile stents are also less likely to induce thrombosis or cause other complications to patients after implantation.

[0012] Various intravascular stents have been proposed in the prior art, such as CN Patent Publication No. 106137481, U.S. Patent Nos. 4,512,338, 4,733,665, 7,037,330, 7,695,507 and 8,518,102, and U.S. Patent Publication No. 2015 / 0209165; however, significant progress is still needed to optimize the radial strength associated with the stent profile.

[0013] For example, CN Patent Publication No. 106137481 discloses an intravascular stent comprising a plurality of unit rings arranged in a tubular structure. The unit rings are composed of a first unit ring and a second unit ring of different shapes. The first unit ring and the second unit ring are both symmetrical around their center points. The two unit rings are at an angle θ relative to the horizontal axis so that a spiral structure is formed when the unit rings are formed on the tube. There is an angle β1 between the centerline of the first unit ring and the tangential axis of the stent strut. The second unit ring has an angle β2 formed in the same manner. Prior art theory holds that β1>β2. Prior art theory holds that this intravascular stent is formed by laser cutting shape memory alloys such as nitinol. CN Patent Publication No. 106137481 discloses that the design will have good radial force and flexibility properties, making it practical for clinical applications. However, this design requires the stent to be deployed in a segmented manner, with each column of units deployed separately in an uneven and more traumatic manner. In addition, the angle θ gives the stent a spiral structure, so that multiple rows of unit rings are spiral along the length of the stent. When the stent bends, a torsional motion is induced, thereby causing additional relative motion against the vessel wall. In addition, the stent design disclosed in CN Patent Publication No. 106137481 does not distinguish between radial load and longitudinal load load conditions, which limits the amount of radial force or strength that can be applied to the stent.

[0014] Conventional solutions to increase radial strength require increasing the geometry of the stent (increasing wall thickness or strut width), which reduces stent flexibility and increases the cross-sectional profile. It stands to reason that a stent design that provides greater radial strength than current stent designs while maintaining stent flexibility and a low cross-sectional profile would be advantageous because, in order to be consistent with currently expected radial strength properties, the geometry of the stent (e.g., wall thickness, strut width) could be reduced while still providing the expected levels of radial strength and flexibility.

[0015] Therefore, there is a need for a stent that will provide high radial strength without compromising flexibility and that allows for a lower profile design. Various aspects of the present invention satisfy these needs and provide further related advantages, as described in the following summary of the invention.

[0016] It should be noted that the above description of the background technology includes information that may be helpful in understanding various aspects of the present invention. This does not mean that any information provided herein is prior art or related to the invention currently claimed, nor does it mean that any publication explicitly or implicitly cited herein is prior art. Summary of the invention

[0017] Aspects of the present invention provide certain benefits in construction and use resulting in the exemplary advantages described below.

[0018] The present invention solves the above problems by providing a stent having a substantially tubular body, which is disclosed and configured to have a relatively small profile design, providing relatively high radial strength without compromising flexibility. In at least one embodiment, the stent provides a skeleton with a plurality of interconnected struts, which form a plurality of radial axial rows of radial support units and a plurality of flexible axial rows of flexible support units. A plurality of radial axial rows and a plurality of flexible axial rows are arranged in an alternating pattern along the circumferential axis of the stent. The central axis of each radial axial row and flexible axial row is parallel to the longitudinal axis of the stent. Each radial axial row is arranged to be offset from each adjacent radial axial row along the longitudinal axis of the stent. Each radial support unit is formed by four struts of the plurality of interconnected struts of the skeleton, and the four struts are arranged to be symmetrical along both the longitudinal axis and the circumferential axis of the stent.

[0019] Other features and advantages of aspects of the invention will become apparent from the following more detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of aspects of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings illustrate various aspects of the invention. In these drawings:

[0021] Figure 1 is a plan view of a plurality of interconnected struts forming an exemplary stent in an unconstrained state according to at least one embodiment;

[0022] Figure 2A is in a radially constrained state according to at least one embodiment Figure 1 A plan view of the bracket;

[0023] Figure 2B is in a longitudinally restrained state according to at least one embodiment Figure 1 A plan view of the bracket;

[0024] Figure 3 According to at least one embodiment Figure 1 Tubular view of the stent;

[0025] Figure 4is a view of an exemplary radial strut unit of a stent in a radially constrained state according to at least one embodiment, wherein the vertical strut angle is -29°;

[0026] Figure 5 is a view of an exemplary radial strut unit of a stent in an unconstrained state according to at least one embodiment, wherein the vertical strut angle is 0°;

[0027] Figure 6 is a view of an exemplary radial strut unit of a stent in a longitudinally constrained state according to at least one embodiment, wherein the vertical strut angle is 45°;

[0028] Figure 7 is a view of an exemplary radial strut unit of a stent in a longitudinally constrained state according to at least one embodiment, wherein the vertical strut angle is 58°;

[0029] Figure 8 is a view of an exemplary radial strut unit of a stent in a longitudinally constrained state according to at least one embodiment, wherein the vertical strut angle is 76°;

[0030] Fig. 9 is a view of an exemplary radial strut unit of a stent in a longitudinally constrained state according to at least one embodiment, wherein the vertical strut angle is 83°;

[0031] Fig.10 is a view of an exemplary radial strut unit of a stent in a longitudinally constrained state according to at least one embodiment, wherein the vertical strut angle is 89°;

[0032] Fig.11 is a view of an exemplary radial strut unit of a stent in a longitudinally constrained state according to at least one embodiment, wherein the vertical strut angle is 99°;

[0033] Fig.12 is a graph of approximate radial forces ("RF") in pounds exhibited by an exemplary radial strut unit of a stent having a given vertical strut angle for different levels of displacement, according to at least one embodiment;

[0034] Fig.13 is a graph of approximate vertical stent unit angles plotted against stent stiffness according to at least one embodiment;

[0035] Fig.14 is a plan view of a plurality of interconnected struts forming another exemplary stent in an unconstrained state according to at least one embodiment;

[0036] Fig.14 A is according to at least one embodiment Fig.14 an exemplary enlarged view of a circled portion defined in;

[0037] Fig.14 B is according to at least one embodiment Fig.14 an alternative exemplary enlarged view of the circled portion defined in; and

[0038] Fig.14 C is according to at least one embodiment Fig.14 Another alternative exemplary enlarged view of the circled portion defined in .

[0039] The above-mentioned accompanying drawings show various aspects of the present invention by at least one exemplary embodiment in its exemplary embodiments, and these exemplary embodiments are further defined in detail in the following description. According to one or more embodiments, the features, elements and aspects of the present invention cited by the same numbers in different drawings represent the same, equivalent or similar features, elements or aspects. DETAILED DESCRIPTION

[0040] Now go to Figure 1 , shows a plan view of a plurality of interconnected struts forming stent 100 in an unconstrained state, according to at least one embodiment. Figure 1 The view in FIG. 1 is a schematic plan view of a stent 100, which in its final form will be rolled into a cylindrical / tubular design similar to Figure 3 As shown. The unconstrained state of the stent 100 corresponds to no radial load and no longitudinal load applied to the stent 100. Therefore, the unconstrained state represents a condition in which the stent 100 has no forces acting on it and is in a balanced or "memory" state. First, it should be noted that the embodiments of the stent 100 depicted in the accompanying drawings are merely exemplary and are shown for illustrative purposes. Therefore, in other embodiments, the stent 100 (and each of the components of the stent 100 described herein) may adopt any other size, shape, dimension and / or configuration now known or later developed, which depends at least in part on the specific circumstances in which the stent 100 is used, as long as the stent 100 can basically achieve the functions described herein.

[0041] In at least one embodiment, the stent 100 is made from a single piece of laser-cut material having shape memory and superelastic properties, such as nitinol; however, in other embodiments, the stent 100 may be formed from any other material (or combination of materials) now known or later developed that enables the stent 100 to substantially perform the functions described herein.

[0042] In at least one embodiment, the stent 100 includes multiple parts, namely a proximal end 104, a distal end 101, and a framework including a plurality of radial struts 102 and a plurality of flexible struts 103. In at least one embodiment, the proximal end 104 of the stent 100 has an open design rather than a closed design to provide a potential location for attachment to a corresponding delivery system.

[0043] In at least one embodiment, the stent 100 provides at least one radiopaque element 116 (e.g., a marker) that is positioned and configured to improve visibility and ease of use during the insertion or deployment process. In at least one embodiment, at least one radiopaque element 116 is positioned on one or both of the proximal end 104 and the distal end 101 of the stent 100. In at least one embodiment, at least one radiopaque element 116 is positioned elsewhere along the length (skeleton 115) of the stent 100. In at least one such embodiment, at least one radiopaque element 116 is composed of a tungsten-containing polymer. In other embodiments, at least one radiopaque element 116 may be composed of platinum, chromium, cobalt, tantalum, nitinol, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel or their alloys, or any other radiopaque material (or combination of materials) now known or later developed.

[0044] In at least one embodiment, the distal end 101 of the stent 100 is similar in shape to the radial struts 102, except that the distal end 101 terminates in a rounded edge rather than being attached to a continuous aspect of the stent 100 design. In at least one embodiment, both the proximal end 104 and the distal end 101 of the stent 100 can terminate at the end of a repeating junction so that the entire body of the stent 100 is symmetrical. In at least one alternative embodiment, one or both of the proximal end 104 and the distal end 101 of the stent 100 can terminate in an open design to provide for placement of an additional radiopaque element 116, attachment to a delivery system, or to provide an additional atraumatic edge.

[0045] In at least one embodiment, each radial strut 102 is arranged from four struts, wherein the struts are symmetrical along both the x-axis (longitudinal axis) and the y-axis (circumferential axis) of the stent 100. In at least one embodiment, the radial struts 102 are repeated in radial axial rows 120 along the length of the stent 100. Additionally, in at least one embodiment, each flexible strut 103 is arranged from four struts, wherein the flexible struts 103 are repeated in flexible axial rows 125 along the length of the stent 100 that are adjacent to the radial axial rows 120 of the radial struts 102. In at least one embodiment, each flexible strut 103 has mirror symmetry with a corresponding flexible strut 103 in another flexible axial row 125 of the flexible struts 103 in the circumferential direction. In at least one embodiment, the radial axial rows 120 of the radial struts 102 alternate with the flexible axial rows 125 of the flexible struts 103 circumferentially around the stent 100.

[0046] In at least one embodiment, the radial support unit 102 and the flexible support unit 103 are formed of uninterrupted material to form a unitary structure of the stent 100. In at least one alternative embodiment, as Fig.14 and Fig.14 As shown in Figure 1, adjacent radial support units 102 and flexible support units 103 are interrupted by intentional splits 112 therebetween to form a discontinuous geometry. In at least one such embodiment, the splits 112 are then reconnected using coils 114. Such connections via coils 114 enable multi-axial movement of the joint to maximize the flexibility of the stent 100 when positioned within a target treatment vessel. In at least one embodiment, each coil 114 is composed of a tungsten-containing polymer. In other embodiments, each coil 114 may be composed of platinum, platinum-iridium, chromium, cobalt, tantalum, nitinol, nitinol composites, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel or their alloys, or any other radiopaque material (or combination of materials) now known or later developed.

[0047] Figure 2A shows the radially constrained state Figure 1 In at least one embodiment, when a radial load or force acts on the stent 100, the opposing vertical struts 110 of each radial support unit 102 bend inwardly toward each other. Figure 1In the unconstrained state shown, the opposing vertical struts 110 of each radial strut unit 102 are substantially perpendicular to the central axis of the radial axial row 120 of the radial strut unit 102. In addition, since the central axis of the radial axial row 120 is parallel to the longitudinal axis of the stent 100, the vertical struts 110 are also substantially perpendicular to the longitudinal axis of the stent 100 in the unconstrained state. In at least one alternative embodiment, the vertical struts 110 of each radial strut unit 102 are less than vertical in the unconstrained state, wherein the vertical strut angle is less than 0°, to facilitate bending under radial loads or radial forces.

[0048] Figure 2B Shows the longitudinally constrained state Figure 1 100. In at least one embodiment, when an axial tensile force or a longitudinal force acts on the stent 100, the vertical struts 110 of each radial support unit 102 are deformed outwardly from each other.

[0049] In at least one embodiment, the flexible support units 103 exist in axial (horizontal) unit rows to separate the radial support units 102. In addition, in at least one embodiment, the shape of the flexible support units 103 allows adjacent radial support units 102 to be spaced and offset from each other in the circumferential direction, which further improves the flexibility of the stent 100 while maintaining radial strength.

[0050] Figure 4 A plan view of a radial support unit 102 in a radially constrained state is depicted. In at least one embodiment, each radial support unit 102 includes four vertical struts 110 and defines a joint vertex 105, a top arc 106, and a vertical strut angle 107. In at least one embodiment, each vertical strut 110 is in a substantially vertical or less than vertical configuration when in an unconstrained or unloaded state, such as Figure 5 As shown. Figure 5 In the unconstrained configuration shown, each radial strut 102 is able to accommodate different types of applied loads, such as radial compression or loading observed in a vessel, or axial tensile stresses observed when stent 100 is loaded into a delivery system. In the unconstrained configuration, the geometry of each radial strut 102, including joint apex 105 and top arc 106, has gently curved edges to further support flexibility and conformity to the tubular nature of the vessel.

[0051] In at least one embodiment, when stent 100 is implanted in a blood vessel, the blood vessel will radially compress stent 100. The continuous radial force exerted by stent 100 on the blood vessel prevents the blood vessel from recoil or occlusion, ensuring that blood can flow freely down the treated blood vessel. The continuous radial force exerted by stent 100 on the blood vessel also ensures that stent 100 will be properly attached to the blood vessel wall to prevent movement during and after the implantation process. In at least one embodiment, when stent 100 is radially compressed by the blood vessel, the vertical struts 110 of each radial strut unit 102 will begin to bend inwardly, forming a vertical strut angle 107 of less than 0°, such as Figure 4 As shown. This bending action increases the radial strength of the stent 100. Since the radial strength is obtained by the bending action, the radial strength is high relative to the geometry of the individual vertical struts 110. Therefore, in order to keep the stent 100 consistent with the generally accepted radial strength values, the stent geometry (e.g., wall thickness, strut width) can be proportionally reduced. By reducing the geometric size of the stent, the overall cross-sectional profile can be reduced. In addition, the footprint of the stent 100 on the treated blood vessel will be reduced, which may accelerate healing in vivo.

[0052] In at least one embodiment, when a given radial support unit 102 is in Figure 4 In the radial loading configuration shown, all aspects of the geometry remain circular, with the top arc 106 and vertical strut arc 108 maximized to reduce internal stress and strain in the design and, therefore, minimize the risk of high stress failure. Conversely, the strong radial strength provided by the radial struts 102 can be offset by applying a tensile load along the axis of the two opposing joint vertices 105. This allows the stent 100 to be loaded into a delivery system without the need to counteract the forces of tension in the delivery system. Figure 4 High radial strength observed during bending in. Figures 6 to 11 It is shown that the vertical strut angle 107 of the radial strut unit 102 changes from about 45° to about 99° as the amount of axial tension or longitudinal force applied to the radial strut unit 102 increases. When a tensile load is applied to the stent 100, the vertical strut angle 107 will increase, and in turn, the radial strength provided by the radial strut unit 102 will decrease. This allows for a simple and relatively low stress method of loading the stent 100 into a sheath or delivery system. Figures 6 to 11 In the tensile loading configuration shown, all aspects of the geometry remain circular, with most of the movement of the vertical struts 110 concentrated within the top apex 106 .

[0053] Fig.12A graphical representation of the radial force ("RF") in pounds provided by each radial strut unit 102 for a given displacement is shown in at least one embodiment. Eight different lines are presented in the graph, each representing a radial strut unit 102 having a different vertical strut angle 107. The top line 1210 corresponds to a vertical strut angle of -29°, while the stent 100 is in a radially constrained state. Line 1220 corresponds to a vertical strut angle of 0°, while the stent 100 is in an unconstrained state. Line 1230 corresponds to a vertical strut angle of 45°, while the stent 100 is in a longitudinally constrained state. Line 1240 corresponds to a vertical strut angle of 58°, while the stent 100 is in a longitudinally constrained state. Line 1250 corresponds to a vertical strut angle of 76°, while the stent 100 is in a longitudinally constrained state. Line 1260 corresponds to a vertical strut angle of 83°, while the stent 100 is in a longitudinally constrained state. Line 1270 corresponds to a vertical strut angle of 89° while the stent 100 is in a longitudinally constrained state. Line 1280 corresponds to a vertical strut angle of 99° while the stent 100 is in a longitudinally constrained state. In some embodiments of the present invention, the vertical strut angle 107 may be less than 0° when in an unconstrained state. The graph shows that at high displacements of about 0.01 inches, the corresponding radial force for a vertical strut angle 107 of 0° or -29° is more than twice the corresponding radial force for a vertical strut angle 107 of 76° or greater. In general, as the vertical strut angle 107 increases, the radial force decreases dramatically. This allows the stent 100 to have increased flexibility when in a longitudinally constrained state during deployment in a vessel (lumen).

[0054] Fig.13 A graphical representation of the stiffness (ie, flexibility) of the stent 100 versus the vertical strut angle 107 is shown in at least one embodiment. Fig.13 As shown, when the vertical strut angle 107 increases with increasing longitudinal load or axial tension, the stent stiffness measured by the stent reaction force decreases. This observation further demonstrates that the radial strut unit 102 can have different properties (improved strength and improved flexibility) depending on its configuration (radially constrained or longitudinally constrained).

[0055] The above features of the exemplary embodiments of the stent 100 provide significant, non-obvious improvements and advantages over known prior art stents. For example, although the stent described in CN Patent Publication No. 106137481 includes radial support units and flexible support units that allow the stent to be used in large-sized lumens, the design is based on the angle of the first unit ring being greater than the angle of the second unit ring. In contrast, in at least one embodiment of the stent 100, the unit angle corresponding to the angle disclosed in CN Patent Publication No. 106137481 is not important.

[0056] In contrast, at least one embodiment of the stent 100 is based on the discovery that the vertical strut angle 107 plays a key role in significantly increasing both the radial strength properties and flexibility of the stent 100. In at least one embodiment, the vertical strut angle 107 is designed to be variable based on the type of load applied to the stent 100, thereby providing different loading conditions for radial loads and longitudinal loads. When in radial compression, the vertical struts 110 will bend or reverse, thereby dramatically increasing the radial force. While under longitudinal loads, the vertical struts 110 will extend, thereby dramatically reducing the radial force. In contrast, the known prior art does not distinguish between radial loads and longitudinal loads.

[0057] Secondly, the stent described in CN Patent Publication No. 106137481 includes multiple rows of unit rings, which are stacked on each other circumferentially in a radial configuration, or stacked on each other vertically in a two-dimensional configuration. Therefore, the circumferential axis of each unit ring is aligned along an axis. The aligned arrangement allows the stent to be deployed in a segmented manner, wherein each column of units is deployed individually.

[0058] In contrast, in at least one embodiment, each radial strut unit 102 (corresponding to a unit ring) is staggered or offset along the circumferential axis so that adjacent radial axial rows 120 of radial strut units 102 do not share an aligned central axis. This staggered arrangement ensures that the stent 100 will be deployed in a continuous manner, with each column of radial strut units 102 deployed together with adjacent radial strut units 102. Compared to CN Patent Publication No. 106137481, this difference in stent design makes the deployment of the stent more uniform and non-traumatic.

[0059] Third, although CN Patent Publication No. 106137481 discloses a row of unit rings, wherein these unit rings are aligned at an angle θ along a line in a linear design, the stent has a spiral structure so that multiple rows of unit rings are spiral along the length of the stent. In contrast, in at least one embodiment, each radial support unit 102 (corresponding to a unit ring) in a radial axial row 120 is aligned along a line parallel to the central axis of the stent 100 in a linear design, and therefore does not have any angle or spiral structure. In CN Patent Publication No. 106137481, when the stent is bent to move through a blood vessel, it will cause a torsional motion, which may cause additional relative motion against the vessel wall. In at least one embodiment, the design of the stent 100 ensures that the stent 100 is simply bent without any torsional motion, thereby minimizing any relative motion against the vessel wall.

[0060] These differences in stent design lead to completely different behaviors. In CN Patent Publication No. 106137481, the stent will produce similar reactions under longitudinal loads and radial loads, so that multiple rows of unit rings or units will be compressed and elongated relative to the central axis of the stent. On the other hand, at least one embodiment of the stent 100 reacts differently to longitudinal loads and radial loads, with a response optimized for each situation. Longitudinal loads are usually applied during loading or withdrawal, when the required radial force is small. Radial loads are usually applied after the stent 100 has reached its intended treatment position and is in contact with the vessel wall, when the required radial force is large. In at least one embodiment, under radial loads, the vertical struts 110 will reverse or bend, resulting in a negative vertical strut angle 107, thereby significantly increasing the radial force of the stent. In this way, in at least one embodiment, the stent 100 provides a mechanism for providing high radial force under radial loads and low radial force under longitudinal loads, while the known prior art stents do not distinguish between these two types of loads.

[0061] Aspects of this specification may also be described as follows:

[0062] 1. A stent having a substantially tubular body, comprising: a proximal end and an opposite distal end; and a skeleton having a plurality of interconnected struts, the plurality of interconnected struts forming a plurality of radial axial rows of radial support units and a plurality of flexible axial rows of flexible support units; wherein the plurality of radial axial rows and the plurality of flexible axial rows are arranged in an alternating pattern along the circumferential axis of the stent; wherein the central axis of each radial axial row and the flexible axial row is parallel to the longitudinal axis of the stent; wherein each radial axial row is arranged to be offset relative to each adjacent radial axial row along the longitudinal axis of the stent; and wherein each radial support unit is formed by four struts of the plurality of interconnected struts of the skeleton, the four struts being arranged to be symmetrical along both the longitudinal axis and the circumferential axis of the stent.

[0063] 2. A stent according to embodiment 1, wherein each flexible support unit is formed by four struts of a plurality of interconnected struts of the skeleton, the four struts being arranged such that two adjacent flexible axial rows have mirror symmetry along the longitudinal axis of the stent.

[0064] 3. The stent according to embodiments 1 to 2, wherein for each radial strut unit, the four struts forming the radial strut unit are arranged such that a pair of opposing vertical struts are oriented substantially perpendicular to the longitudinal axis of the stent.

[0065] 4. The stent according to embodiments 1 to 3, wherein the vertical struts of each radial support unit are configured to bend inwardly toward each other when subjected to radial forces.

[0066] 5. The stent according to embodiments 1 to 4, wherein the vertical struts of each radial support unit are configured to deform from a linear shape to a curved shape having a large radius when the vertical struts are subjected to radial forces.

[0067] 6. The stent according to embodiments 1 to 5, wherein the vertical struts of each radial support unit are configured to deform outwardly toward each other when subjected to tension when the stent is in a longitudinally constrained configuration.

[0068] 7. A stent according to embodiments 1 to 6, wherein the angle between struts is greater than 0° when the stent is in a longitudinally constrained configuration.

[0069] 8. A stent according to embodiments 1 to 7, wherein the radial force applied by the stent when the stent is in a longitudinally constrained configuration is less than the radial force when the stent is in each of an unconstrained configuration and a radially constrained configuration.

[0070] 9. The stent according to embodiments 1 to 8, wherein radial forces exerted by the stent when the stent is in the longitudinally constrained configuration allow the stent to be compressed and loaded into a stent delivery system for insertion into a body lumen.

[0071] 10. The stent according to embodiments 1 to 9, further comprising at least one radiopaque element formed on the stent.

[0072] 11. The stent according to embodiments 1 to 10, wherein at least one radiopaque element is positioned on one or both of the proximal end and the distal end of the stent.

[0073] 12. The stent according to embodiments 1 to 11, wherein at least one radiopaque element is positioned along the length of the stent.

[0074] 13. The stent according to embodiments 1 to 12, wherein at least one radiopaque element is composed of at least one of a tungsten-containing polymer, platinum, chromium, cobalt, tantalum, nitinol, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel, or alloys thereof.

[0075] 14. The stent according to embodiments 1 to 13, wherein: adjacent radial struts are interrupted by a split therebetween; and adjacent radial struts are reconnected by a coil spanning the split therebetween.

[0076] 15. The stent according to embodiments 1 to 14, wherein each coil is composed of at least one of a tungsten-containing polymer, platinum, platinum-iridium, chromium, cobalt, tantalum, nitinol, a nitinol composite, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel, or alloys thereof.

[0077] 16. The stent according to embodiments 1 to 15, wherein the stent is composed of a single piece of laser cut material having shape memory and superelastic properties.

[0078] 17. A stent having a substantially tubular body, comprising: a proximal end and an opposite distal end; and a skeleton having a plurality of interconnected struts, the plurality of interconnected struts forming a plurality of radial axial rows of radial support units and a plurality of flexible axial rows of flexible support units; wherein the plurality of radial axial rows and the plurality of flexible axial rows are arranged in an alternating pattern along the circumferential axis of the stent; wherein the central axis of each radial axial row and the flexible axial row is parallel to the longitudinal axis of the stent; wherein each radial axial row is arranged to be offset relative to each adjacent radial axial row along the longitudinal axis of the stent; wherein each radial support unit is formed by four of the plurality of interconnected struts of the skeleton, the four struts being arranged to be symmetrical along both the longitudinal axis and the circumferential axis of the stent; and wherein each flexible support unit is formed by four of the plurality of interconnected struts of the skeleton, the four struts being arranged so that two adjacent flexible axial rows have mirror symmetry along the longitudinal axis of the stent.

[0079] 18. A stent having a substantially tubular body, comprising: a proximal end and an opposite distal end; a skeleton having a plurality of interconnected struts, the plurality of interconnected struts forming a plurality of radial axial rows of radial support units and a plurality of flexible axial rows of flexible support units; and at least one radiopaque element formed on the stent; wherein the plurality of radial axial rows and the plurality of flexible axial rows are arranged in an alternating pattern along the circumferential axis of the stent; wherein the central axis of each radial axial row and the flexible axial row is parallel to the longitudinal axis of the stent; wherein each radial axial row is arranged to be offset relative to each adjacent radial axial row along the longitudinal axis of the stent; and wherein each radial support unit is formed by four struts of the plurality of interconnected struts of the skeleton, the four struts being arranged to be symmetrical along both the longitudinal axis and the circumferential axis of the stent.

[0080] Finally, with respect to the exemplary embodiments of the present invention as shown and described herein, it should be understood that the neurovascular stent is disclosed and configured to have a relatively small profile design, providing relatively high radial strength without compromising flexibility. Because the principles of the present invention can be implemented in a variety of configurations other than those shown and described, it should be understood that the present invention is not limited in any way to the exemplary embodiments, but rather generally relates to neurovascular stents and can be implemented in a variety of forms without departing from the spirit and scope of the present invention. Those skilled in the art will also understand that the present invention is not limited to the specific geometries and materials of construction disclosed, but may alternatively employ other functionally equivalent structures or materials now known or later developed without departing from the spirit and scope of the present invention.

[0081] Certain embodiments of the present invention are described herein, including the best mode known to the inventor for carrying out the present invention. Of course, after reading the foregoing description, variations of these described embodiments will become apparent to those of ordinary skill in the art. The inventors expect that the skilled person will appropriately adopt such variations, and the inventors intend that the present invention be implemented in a manner different from that specifically described herein. Therefore, the present invention includes all variations and equivalent substitutions of the subject matter described in the appended claims as permitted by applicable law. In addition, the present invention encompasses any combination of the above-described embodiments in all possible variations thereof, unless otherwise stated herein or clearly contradictory to the context.

[0082] The grouping of alternative embodiments, elements or steps of the present invention should not be construed as limiting. Each group member may be referred to and claimed individually or in any combination with other group members disclosed herein. It is contemplated that, for reasons of convenience and / or patentability, one or more members in a group may be included in or deleted from the group. When any such inclusion or deletion occurs, it is considered that this specification includes the modified group, thereby satisfying the written description of all Markush groups used in the appended claims.

[0083] Unless otherwise stated, all numbers used in this specification and claims to represent characteristics, items, quantities, parameters, properties, terms, etc. should be understood to be modified by the terms "about" and "approximately" in all cases. As used herein, the terms "about" and "approximately" mean that the defined characteristics, items, quantities, parameters, properties or terms are included in the range of plus or minus ten percent above and below the value of the characteristics, items, quantities, parameters, properties or terms. Therefore, unless otherwise indicated, the numerical parameters set forth in the specification and the attached claims are approximate values ​​that can vary. At least, and without attempting to limit the application of the doctrine of equivalents within the scope of the claims, each digital indication should be interpreted at least according to the number of reported significant figures and by applying ordinary rounding techniques. Although the numerical ranges and values ​​that set forth the wide range of the present invention are approximate values, the numerical ranges and values ​​set forth in the specific examples should be reported as accurately as possible. However, any numerical range or value essentially contains certain errors, which are necessarily caused by the standard deviation in their corresponding test measurements. The description of the numerical range herein is intended only as a shorthand method for individually referring to each individual value falling within the range. Unless otherwise indicated herein, each individual value of a numerical range is incorporated into the specification as if it were individually recited herein. Similarly, as used herein, unless indicated to the contrary, the term "substantially" is a term of degree intended to indicate the degree of approximation of a defined characteristic, item, quantity, parameter, property, or term, encompassing a range that can be understood and interpreted by one of ordinary skill in the art.

[0084] The use of the terms "may" or "can" to refer to an embodiment or an aspect of an embodiment also carries the alternative meaning of "may not" or "cannot". Thus, if the specification discloses that an embodiment or an aspect of an embodiment may or can be included as part of the present subject matter, a negative limitation or exclusive proviso is also expressly intended to mean that the embodiment or an aspect of an embodiment may not or cannot be included as part of the present subject matter. Similarly, the use of the term "optionally" when referring to an embodiment or an aspect of an embodiment means that such embodiment or an aspect of the embodiment may or may not be included as part of the present subject matter. Whether such a negative limitation or exclusive proviso applies will be based on whether the negative limitation or exclusive proviso is recited in the claimed subject matter.

[0085] There is no quantifier before the element used in the context of describing the present invention (especially in the context of the following claims) and should be interpreted as including both the singular and the plural, unless otherwise specified herein or obviously contradictory with the context. In addition, ordinal indicators for identifying elements, such as "first", "second", "third", etc., are used to distinguish elements, and do not indicate or imply the required or limited number of such elements, and do not indicate the specific position or order of such elements, unless otherwise specified. All methods described herein can be carried out in any suitable order, unless otherwise specified herein or obviously contradictory with the context. The use of any and all examples or exemplary languages ​​(for example, "such as") provided herein is only intended to better illustrate the present invention, and is not intended to limit the scope of protection claimed by the present invention. Any language in this specification should not be interpreted as indicating any unclaimed element necessary for the implementation of the present invention.

[0086] When used in a claim, whether as filed or as added by amendment, the open transition term "comprising" (together with its equivalent open transition phrases, such as "including," "containing," and "having") encompasses all explicitly recited elements, limitations, steps, and / or features, whether used alone or in combination with unrecited subject matter; the named elements, limitations, and / or features are essential, but other unrecited elements, limitations, and / or features may be added and still constitute structure within the scope of the claim. The specific embodiments disclosed herein may be further limited in the claims using the closed transition phrases "consisting of" or "consisting essentially of" in place of "comprising" or as a modification of "comprising." When used in a claim, whether as filed or as added by amendment, the closed transition phrase "consisting of" excludes any element, limitation, step, or feature not explicitly recited in the claim. The closed transition phrase "consisting essentially of" limits the scope of the claim to the explicitly recited elements, limitations, steps, and / or features, as well as any other elements, limitations, steps, and / or features that do not materially affect the basic and novel characteristics of the claimed subject matter. Thus, the open transition phrase "comprising" is defined to include all specifically recited elements, limitations, steps, and / or features, as well as any optional, additional, unspecified elements, limitations, steps, and / or features. The closed transition phrase "consisting of" is defined to include only those elements, limitations, steps, and / or features specifically recited in the claim, while the closed transition phrase "consisting essentially of" is defined to include only those elements, limitations, steps, and / or features specifically recited in the claim, as well as those elements, limitations, steps, and / or features that do not materially affect the basic and novel characteristics of the claimed subject matter. Thus, the open transition phrase "comprising" (together with its equivalent open transition phrases) includes within its meaning, in a limited manner, the claimed subject matter specified by the closed transition phrase "consisting of" or "consisting essentially of". Therefore, the embodiments described or claimed herein with the phrase "comprising" have expressly or essentially unambiguously described, enabled and supported the phrases "consisting essentially of" and "consisting of."

[0087] Any claim intended to be processed under 35 U.S.C. § 112(f) will be preceded by the words "means for," but use of the term "for" in any other context is not intended to invoke processing under 35 U.S.C. § 112(f). Applicants therefore reserve the right to file additional claims in this or a continuation application after the filing of this application.

[0088] It should be understood that any method disclosed herein and the order of the corresponding elements of any such method are merely exemplary. Depending on the specific implementation, they can be performed in any order or in parallel, unless otherwise specified in the present disclosure.

[0089] All patents, patent publications and other publications cited and identified in this specification are individually and explicitly incorporated herein by reference in their entirety to describe and disclose compositions and methods that can be used in conjunction with the present invention, such as those described in such publications. These publications are provided only because their disclosure precedes the filing date of the present application. In this regard, nothing should be construed as an admission that the inventor has no right to precede such disclosure by virtue of existing inventions or for any other reason. All statements or representations about the dates and contents of these documents are based on information available to the applicant and do not constitute any admission of the correctness of the dates or contents of these documents.

[0090] Although various aspects of the present invention have been described with reference to at least one exemplary embodiment, it should be clearly understood by those skilled in the art that the present invention is not limited thereto. On the contrary, the scope of the present invention is interpreted only in conjunction with the appended claims, and it is hereby expressly pointed out that the inventors consider the subject matter claimed to be the present invention.

Claims

1. A stent having a substantially tubular body, comprising: a proximal end and an opposing distal end; and a skeleton having a plurality of interconnected struts forming a plurality of radial axial rows of radial strut units and a plurality of flexible axial rows of flexible strut units; wherein the plurality of radial axial rows and the plurality of flexible axial rows are arranged in an alternating pattern along a circumferential axis of the stent; wherein the central axis of each radial axial row and the flexible axial row is parallel to the longitudinal axis of the stent; wherein each radial-axial row is arranged to be offset relative to each adjacent radial-axial row along a longitudinal axis of the stent; and Each radial support unit is formed by four struts among the plurality of interconnected struts of the skeleton, and the four struts are arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent.

2. A stent according to claim 1, wherein each flexible support unit is formed by four struts among a plurality of interconnected struts of the skeleton, and the four struts are arranged so that two adjacent flexible axial rows have mirror symmetry along the longitudinal axis of the stent.

3. The stent of claim 1, wherein for each of the radial support units, four struts forming the radial support unit are arranged such that a pair of opposing vertical struts are oriented substantially perpendicular to a longitudinal axis of the stent. 4 . The stent of claim 3 , wherein the vertical struts of each radial support unit are configured to bend inwardly toward each other when subjected to radial forces. 5 . The stent according to claim 4 , wherein the vertical strut of each radial support unit is configured to deform from a linear shape to a curved shape having a large radius when the vertical strut is subjected to a radial force.

6. The stent of claim 3, wherein when the stent is in the longitudinally constrained configuration, the vertical struts of each radial support unit are configured to deform outwardly toward each other when subjected to tension.

7. The stent of claim 6, wherein the angle between the struts is greater than 0° when the stent is in a longitudinally constrained configuration.

8. The stent of claim 6, wherein the radial force applied by the stent when the stent is in a longitudinally constrained configuration is less than the radial force when the stent is in each of an unconstrained configuration and a radially constrained configuration.

9. The stent of claim 8, wherein radial forces exerted by the stent when the stent is in the longitudinally constrained configuration allow the stent to be compressed and loaded into a stent delivery system for insertion into a body lumen.

10. The stent of claim 1, further comprising at least one radiopaque element formed on the stent.

11. The stent of claim 10, wherein the at least one radiopaque element is positioned on one or both of a proximal end and a distal end of the stent.

12. The stent of claim 10, wherein the at least one radiopaque element is positioned along the length of the stent.

13. The stent of claim 10, wherein the at least one radiopaque element is comprised of at least one of a tungsten-containing polymer, platinum, chromium, cobalt, tantalum, nitinol, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel, or alloys thereof.

14. The stent according to claim 1, wherein: Adjacent radial support units are interrupted by splits therebetween; and Adjacent radial support units are reconnected by coils spanning the gaps therebetween.

15. The stent of claim 14, wherein each coil is composed of at least one of a tungsten-containing polymer, platinum, platinum-iridium, chromium, cobalt, tantalum, nitinol, a nitinol composite, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel, or alloys thereof.

16. The stent of claim 1, wherein the stent is comprised of a single piece of laser cut material having shape memory and superelastic properties.

17. A stent having a substantially tubular body, comprising: a proximal end and an opposing distal end; and a skeleton having a plurality of interconnected struts forming a plurality of radial axial rows of radial strut units and a plurality of flexible axial rows of flexible strut units; wherein the plurality of radial axial rows and the plurality of flexible axial rows are arranged in an alternating pattern along a circumferential axis of the stent; wherein the central axis of each radial axial row and the flexible axial row is parallel to the longitudinal axis of the stent; wherein each radial-axial row is arranged to be offset relative to each adjacent radial-axial row along a longitudinal axis of the stent; wherein each radial support unit is formed by four struts of the plurality of interconnected struts of the skeleton, the four struts being arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent; and Each flexible support unit is formed by four struts of the plurality of interconnected struts of the skeleton, and the four struts are arranged so that two adjacent flexible axial rows have mirror symmetry along the longitudinal axis of the stent.

18. A stent having a substantially tubular body, comprising: a proximal end and an opposing distal end; a backbone having a plurality of interconnected struts forming a plurality of radial axial rows of radial struts and a plurality of flexible axial rows of flexible struts; and at least one radiopaque element formed on the stent; wherein the plurality of radial axial rows and the plurality of flexible axial rows are arranged in an alternating pattern along a circumferential axis of the stent; wherein the central axis of each radial axial row and the flexible axial row is parallel to the longitudinal axis of the stent; wherein each radial-axial row is arranged to be offset relative to each adjacent radial-axial row along the longitudinal axis of the stent; and Each radial support unit is formed by four struts among the plurality of interconnected struts of the skeleton, and the four struts are arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent.

Images