Neurovascular stent

Abstract

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

Description

Detailed Description of the Invention

[0001] [Related Applications] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 351,103, filed on June 10, 2022. This application also claims the benefit of the filing date of U.S. Provisional Application No. 63 / 394,376, filed on August 2, 2022. This application also claims the benefit of the filing date of U.S. Provisional Application No. 18 / 203,557, filed on May 30, 2023. The contents of the above applications are incorporated herein by reference.

[0002] [Background Art] The subject matter of this patent application generally relates to the field of endovascular treatment devices, and more specifically to stents for treating weakened vascular lumens due to injury or disease, particularly stents for treating the neurovascular system.

[0003] Any and all patents and published patent applications cited or referenced in this application are hereby incorporated by reference herein by the applicant.

[0004] As background, vascular diseases, particularly those affecting the neurovascular system, including intracranial atherosclerotic disease (ICAD) and aneurysms, have been an important focus of innovation. According to data from the U.S. Centers for Disease Control and Prevention (CDC), in 2020, cerebrovascular diseases were the fifth leading cause of death in the United States.

[0005] One possible treatment for a neurovascular disease such as ICAD or an aneurysm is to place a stent at the affected site. The implanted stent supports the weakened or damaged blood vessel, which further contributes to the treatment of the disease in question. For example, a patient suffering from ICAD has a blocked or partially blocked blood vessel within the neurovascular system, and if this blocked or partially blocked blood vessel is present in an important part of the anatomical structure, it reduces or completely blocks blood flow to the neurovascular system, thus causing a stroke or death in severe cases. Treatment of ICAD may involve placing a very small stent that can support the affected blood vessel, thereby allowing unrestricted blood flow to the distal part of the vascular system and preventing future damage.

[0006] Current stent designs are made from multiple interconnected metal struts and have one of two general forms: self-expanding and balloon-expandable. Self-expanding stents are made from materials with shape memory and superelastic properties such as nitinol. The diameter of this stent matches the diameter of the blood vessel being treated and can vary in the range of 1.5 mm to 4.0 mm or more depending on the desired anatomical location. Self-expanding stents are typically pre-loaded within a tube such as an introducer sheath, which restricts the diameter of the stent until the final treatment position is reached, at which point the diameter restriction is released, allowing the stent to expand to its desired diameter so that it contacts the blood vessel wall directly. Balloon-expandable stents follow a similar method, but instead of being pre-loaded in a tube, the device is wound around a balloon catheter and plastically deformed by the expansion of the underlying balloon after being delivered to the target site until the stent is properly apposed.

[0007] Implanting a stent in the neurovascular system presents several challenges, and since small blood vessels are known to be tortuous, the anatomical challenges for treating these small blood vessels in the neurovascular system have received the most attention. Therefore, in order to appropriately design the stent to address the challenges posed by the anatomical structure of the neurovasculature, the stent needs to be small and flexible while being able to provide the radial strength necessary to treat diseased or damaged blood vessels. Note that since the stent is a permanent implant, the stent must be able to withstand the typical repetitive stresses of the blood vessel and must have a small profile so as not to increase the risk of thrombosis or other side effects due to vascular grafting.

[0008] Since the stent is usually the least bendable part within the stent delivery system, the flexibility of the stent is very important. The stent must not only be able to pass through the tortuous path of the anatomical structure but also conform to the geometric shape of the blood vessel to be treated, which may further include bending or twisting. Therefore, a flexible stent is an absolute requirement for treating various vascular diseases.

[0009] The radial strength of the stent is very important because the role of the stent within the blood vessel is to provide structural support. The radial strength of the stent needs to be large enough so as not to be destroyed by the radial compressive forces generated by the pulsatile flow of the blood and any additional forces applied by the affected area (such as plaque accumulation). In the case of self-expanding stents, the radial strength of the stent must also be sufficient to open the occluded blood vessel to its desired diameter, which requires a high level of radial strength compared to the size of the stent.

[0010] Current stent designs tend to provide stents with the smallest possible profile. Assuming that the flexibility of the stent and the radial strength characteristics of the stent are fixed, it is understood that stents with a relatively small profile will provide better results for the patient. In addition to the advantages regarding flexibility and vascular access, stents with a small profile are less likely to cause thrombosis or other complications to the patient after implantation.

[0011] In the prior art, various intravascular stents have been proposed, for example, CN Patent Publication No. 106137481, US Patent Nos. 4,512,338, 4,733,665, 7,037,330, 7,695,507 and 8,518,102, and US Patent Publication No. 2015 / 0209165, etc. However, considerable progress is still needed to optimize the radial strength associated with the profile of the stent.

[0012] For example, CN Patent Publication No. 106137481 discloses an intravascular stent including a plurality of unit rings disposed in a tubular structure. The unit rings are composed of a first unit ring and a second unit ring with different shapes. Both the first unit ring and the second unit ring are symmetric about their center points. The two unit rings form an angle θ with respect to the horizontal axis such that a helical structure is formed when the unit rings are formed on the tube. The first unit ring has an angle β1 between the center line of the unit ring and the axis in the tangential direction of the stent and struts. The second unit ring has an angle β2 formed in the same manner. In the prior art, it is theoretically considered that β1>β2. In the prior art, it is theorized that such an intravascular stent is formed by laser cutting of a shape memory alloy such as nitinol. CN Patent Publication No. 106137481 discloses that this design has good radial force and flexibility characteristics and is practical for clinical applications. However, in such a design, it is necessary to segment and deploy the stent, and the units in each row are deployed individually in a non-uniform and more traumatic manner. Furthermore, the angle θ enables the stent to have a helical structure such that multiple rows of unit rings are helical along the length of the stent. When the stent bends, torsional movement is caused, and additional relative movement against the blood vessel wall is caused. Furthermore, the stent design disclosed in CN Patent Publication No. 106137481 does not distinguish between the loading conditions of radial load and longitudinal load, which limits the amount of radial force or strength applied to the stent.

[0013] Conventional solutions to improve radial strength require increasing the geometric shape of the stent (increasing the wall thickness or the strut width), which reduces the flexibility of the stent and increases the crossing profile. A stent design that can not only provide greater radial strength than current stent designs, but also maintain the flexibility and low crossing profile of the stent, can reduce the geometric shape of the stent (e.g., wall thickness, strut width) to conform to the current desired radial strength characteristics, and at the same time can still provide the desired level of radial strength and flexibility, so it is considered advantageous.

[0014] Accordingly, there is a current need for stents that provide high radial strength without sacrificing flexibility and enable a relatively small profile design. Various aspects of the present invention all meet these requirements and provide further related advantages as described in the following summary of the invention.

[0015] It should be noted that the above description of the background art includes information that may help in understanding various aspects of the present invention. This does not mean that any of the information provided herein belongs to the prior art or is related to the currently claimed invention, nor does it mean that any publication explicitly or implicitly referenced herein belongs to the prior art.

[0016] 〔Summary of the Invention〕 Each aspect of the present invention has specific advantages in structure and use, resulting in the exemplary advantages described below.

[0017] The present invention solves the above problems by basically providing a stent having a tubular body, and the disclosed stent is configured to have a relatively small profile design and provides a relatively high radial strength without sacrificing flexibility. In at least one embodiment, the stent provides a framework having a plurality of interconnected struts, and the plurality of interconnected struts form a plurality of radial axial columns of radial support units and a plurality of flexible axial columns of flexible support units. The plurality of radial axial columns and the plurality of flexible axial columns are provided in an alternating pattern along the circumferential axis of the stent. The central axis of each of the radial axial columns and the flexible axial columns is parallel to the longitudinal axis of the stent. Each radial axial column is arranged offset from each adjacent radial axial column along the longitudinal axis of the stent. Each radial support unit is formed by four struts of the plurality of interconnected struts of the framework, and the four struts are arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent.

[0018] Other features and advantages of each aspect of the present invention will become apparent from the following more detailed description in conjunction with the accompanying drawings that illustrate the principles of each aspect of the present invention.

Brief Description of the Drawings

[0019] The drawings illustrate each aspect of the present invention. In these drawings,

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[0020] The above drawings show each aspect of the present invention in at least one exemplary embodiment of its exemplary embodiments, and these exemplary embodiments are defined in more detail in the following description. According to one or more embodiments, features, elements, and aspects of the present invention referred to by the same reference numeral in different drawings represent the same, equivalent, or similar features, elements, or aspects.

[0021] 〔Best Mode for Carrying Out the Invention〕 Referring now to FIG. 1, a plan view of a plurality of interconnected struts forming a stent 100 in an unconstrained state, according to at least one embodiment, is shown. The view of FIG. 1 is a schematic plan view of the stent 100 whose final form will be wound into a cylindrical / tubular design, similar to that shown in FIG. 3. The unconstrained state of the stent 100 corresponds to the absence of both radial and longitudinal loads on the stent 100. Thus, the unconstrained state represents a situation where no force is acting on the stent 100 and it is in an equilibrium state or a "memory" state. First, it should be noted that the embodiment of the stent 100 depicted in the drawings is merely exemplary and is shown for illustrative purposes. Thus, in other embodiments, the stent 100 (and each of the components of the stent 100 described herein) can adopt any other size, shape, dimension, and / or configuration currently known or later developed, at least partially in accordance with the particular situation in which the stent 100 is used, as long as the stent 100 can basically achieve the functions described herein.

[0022] In at least one embodiment, the stent 100 is made from a single sheet of laser cut material having shape memory and superelastic properties, such as nitinol, although in other embodiments, the stent 100 may be composed of any other material (or combination of materials) currently known or later developed such that the stent 100 can essentially achieve the functions described herein.

[0023] In at least one embodiment, the stent 100 includes a plurality of parts, namely, a proximal end 104, a distal end 101, and a skeleton including a plurality of radial support units 102 and a plurality of flexible support units 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.

[0024] In at least one embodiment, the stent 100 provides at least one radiopaque element 116 (e.g., a marker) positioned and configured to improve visibility and ease of use during the insertion or deployment process. In at least one embodiment, the at least one radiopaque element 116 is positioned at one or both of the proximal end 104 and the distal end 101 of the stent 100. In at least one embodiment, the at least one radiopaque element 116 is positioned at another location along the length of the stent 100 (skeleton 115). In at least one such embodiment, the at least one radiopaque element 116 is composed of a tungsten-containing polymer. In other embodiments, the 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 an alloy thereof, or any other radiopaque material (or combination of materials) currently known or later developed.

[0025] In at least one embodiment, the distal end 101 of the stent 100 has a shape similar to that of the radial support unit 102, except that the distal end 101 terminates at a circular edge rather than being attached to a continuous surface of the stent 100 design. In at least one embodiment, both the proximal end 104 and the distal end 101 of the stent 100 may terminate at the ends of repeating joints such that the entire body of the stent 100 is symmetric. In at least one alternative embodiment, one or both of the proximal end 104 and the distal end 101 of the stent 100 may terminate in an open design to provide for the placement of additional radiopaque elements 116, attachment to a delivery system, or additional non-traumatic edges.

[0026] In at least one embodiment, each radial support unit 102 is arranged by four struts, of which the struts are symmetric along both the x-axis (longitudinal axis) and the y-axis (circumferential axis) of the stent 100. In at least one embodiment, the radial support units 102 are repeated in a radial axial row 120 along the length of the stent 100. Note that in at least one embodiment, each flexible support unit 103 is arranged by four struts, of which the flexible support unit 103 is repeated in a flexible axial row 125 along the length of the stent 100, and the flexible axial row is adjacent to the radial axial row 120 of the radial support unit 102. In at least one embodiment, each flexible support unit 103 has mirror symmetry with a corresponding flexible support unit 103 within another flexible axial row 125 of the flexible support units 103 along the circumferential direction. In at least one embodiment, the radial axial row 120 of the radial support units 102 and the flexible longitudinal row 125 of the flexible support units 103 are alternating circumferentially around the stent 100.

[0027] In at least one embodiment, the radial support unit 102 and the flexible support unit 103 are formed from a continuous material to form a stent 100 of an integral structure. In at least one alternative embodiment, as shown in FIGS. 14 and 14A, adjacent radial support units 102 and flexible support units 103 are interrupted by an intentional slit 112 therebetween to form a discontinuous geometry. In at least one such embodiment, the slit 112 is then reconnected by using a coil 114. Such a connection via the coil 114 allows for multi-axis movement of the joint to maximize the flexibility of the stent 100 when positioned within the target treatment blood 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 composite, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel, or an alloy thereof, or any other radiopaque material (or combination of materials) known currently or developed in the future.

[0028] FIG. 2A shows a plan view of the stent 100 of FIG. 1 in a radially constrained state. In at least one embodiment, when a radial load or radial force acts on the stent 100, the opposing vertical struts 110 of each radial support unit 102 bend inwardly towards each other. When in the unconstrained state shown in FIG. 1 as compared to the radially constrained state, the opposing vertical struts 110 of each radial support unit 102 are substantially perpendicular to the central axis of the radial axial column 120 of the radial support unit 102. Further, since the central axis of the radial axial column 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 support unit 102 are less perpendicular when in the unconstrained state, wherein the vertical strut angle is less than 0° to facilitate bending under a radial load or radial force.

[0029] FIG. 2B shows a plan view of the stent 100 of FIG. 1 in a longitudinally constrained state. In at least one embodiment, when an axial tension or longitudinal force acts on the stent 100, the vertical struts 110 of each radial support unit 102 deform outwardly from each other.

[0030] In at least one embodiment, the flexible support units 103 are present in an axial (horizontal) unit row to separate the radial support units 102. In at least one embodiment, the shape of the flexible support units 103 allows adjacent radial support units 102 to be circumferentially spaced apart from each other and offset, thereby further improving the flexibility of the stent 100 while maintaining the radial strength.

[0031] FIG. 4 shows a plan view of the radial support unit 102 in a radially constrained state. 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 basically vertical or in a configuration that is not very vertical when in an unconstrained or unloaded state, as shown in FIG. 5. In the unconstrained configuration shown in FIG. 5, each radial support unit 102 can adapt to different types of applied loads such as radial compression or load observed within the blood vessel or axial tensile stress observed when loading the stent 100 into the delivery system. In the unconstrained configuration, the geometric shape (including the joint vertex 105 and the top arc 106) of each radial support unit 102 has a gentle arcuate edge to further support the consistency with flexibility and the tubular characteristics of the blood vessel.

[0032] In at least one embodiment, when the stent 100 is implanted within a blood vessel, the blood vessel radially compresses the stent 100. The continuous radial force applied to the blood vessel by the stent 100 prevents the retraction or occlusion of the blood vessel and ensures that blood can flow freely downward along the blood vessel being treated. The continuous radial force applied to the blood vessel by the stent 100 also ensures that the stent 100 adheres properly to the blood vessel wall so as not to move during and after implantation. In at least one embodiment, when the stent 100 is radially compressed by the blood vessel, the vertical struts 110 of each radial support unit 102 begin to bend inwardly to form a vertical strut angle 107 less than 0°, as shown in FIG. 4. This bending action improves the radial strength of the stent 100. Since the radial strength is obtained by the bending action, the radial strength is high with respect to the geometric shape of the individual vertical struts 110. Thus, in order to match the stent to the normally acceptable radial strength value, the geometric shape of the stent (e.g., wall thickness, strut width) can be proportionally reduced. By reducing the geometric dimensions of the stent, the overall crossing profile can be reduced. Note that the footprint of the stent 100 on the blood vessel being treated is reduced, which may promote in vivo healing.

[0033] In at least one embodiment, when a given radial support unit 102 is in the radial load configuration shown in FIG. 4, all aspects of the geometry remain circular such that the top arc 106 and the vertical strut arc 108 are maximized to reduce internal stresses and strains within the design and thus minimize the risk of high stress failure. Conversely, the strong radial strength provided by the radial support unit 102 can be offset by applying a tensile load along the axis of the two opposing joint vertices 105. In this way, the stent 100 can be loaded into the delivery system without having to counteract the high radial strength observed during bending in FIG. 4. FIGS. 6-11 show that as the amount of axial tension or longitudinal force applied to the radial support unit 102 increases, the vertical strut angle 107 of the radial support unit 102 varies from about 45° to about 99°. When a tensile load is applied to the stent 100, the vertical strut angle 107 increases and conversely, the radial strength provided by the radial support unit 102 decreases. This simplifies the method of loading the stent 100 into the sheath or delivery system and keeps the stresses relatively low. In the tensile load configurations shown in FIGS. 6-11, all aspects of the geometry remain circular and most of the movement of the vertical strut 110 is concentrated within the top vertex 106.

[0034] FIG. 12 shows, in at least one embodiment, a plot of the radial force (``RF'') of the pylon units provided by each radial support unit 102 for a given displacement. The graph shows eight different lines, each line representing a radial support 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 an axially constrained state. Line 1240 corresponds to a vertical strut angle of 58° while the stent 100 is in an axially constrained state. Line 1250 corresponds to a vertical strut angle of 76° while the stent 100 is in an axially constrained state. Line 1260 corresponds to a vertical strut angle of 83° while the stent 100 is in an axially constrained state. Line 1270 corresponds to a vertical strut angle of 89° while the stent 100 is in an axially constrained state. Line 1280 corresponds to a vertical strut angle of 99° while the stent 100 is in an axially constrained state. In some embodiments of the present invention, when in an unconstrained state, the vertical strut angle 107 may be less than 0°. This graph shows that at a displacement of about 0.01 inches high, the radial force corresponding to a vertical strut angle 107 of 0° or -29° is greater than twice the radial force corresponding to a vertical strut angle 107 of 76° or greater. Overall, as the vertical strut angle 107 increases, the radial force decreases rapidly. This causes the stent 100 to increase in flexibility when in an axially constrained state during deployment within a blood vessel (lumen).

[0035] FIG. 13 shows a comparison of the stiffness (i.e., flexibility) of the stent 100 and the vertical strut angle 107 in at least one embodiment. As shown in FIG. 13, as the vertical strut angle 107 increases with an increase in the longitudinal load or axial tension, the stent stiffness measured by the stent reaction force decreases. This observation further demonstrates that the radial support unit 102 can have different properties (improved strength and improved flexibility) depending on its configuration (radial restraint or longitudinal restraint).

[0036] The above features of the exemplary embodiments of the stent 100 provide significant and non-obvious improvements and advantages compared to known prior art stents. For example, the stent described in CN Patent Publication No. 106137481 includes a radial support unit and a flexible support unit that can be used for the stent in a large-sized lumen, but this design is based on the angle of the first unit ring being larger 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.

[0037] In contrast, at least one embodiment of the stent 100 is based on the discovery that the vertical strut angle 107 plays an important role in significantly improving both the radial strength characteristics and the flexibility of the stent 100. In at least one embodiment, the vertical strut angle 107 is designed to vary based on the type of load applied to the stent 100, thereby providing different load conditions for radial and longitudinal loads. In the case of radial compression, the vertical strut 110 bends or flips, rapidly increasing the radial force. Under longitudinal load, the vertical strut 110 extends, rapidly decreasing the radial force. In contrast, in the known prior art, radial and longitudinal loads are not distinguished.

[0038] Next, the stent described in CN Patent Publication No. 106137481 includes a plurality of rows of unit rings that are stacked on top of each other in the circumferential direction in a radial configuration or stacked on top of each other in the vertical direction in a two-dimensional configuration. Therefore, the circumferential axes of each unit ring are aligned along one axis. With the aligned arrangement, the stent is deployed in a segmental manner in which the units of each row are deployed individually.

[0039] In contrast, in at least one embodiment, each radial support unit 102 (corresponding to one unit ring) is staggered or offset along the circumferential axis such that adjacent radial axial rows 120 of the radial support units 102 do not share a central axis that is aligned. This staggered arrangement ensures that the stent 100 is deployed in a continuous manner, and each row of radial support units 102 is deployed together with the adjacent radial support units 102. This difference in stent design allows for a more uniform and atraumatic deployment of the stent compared to CN Patent Publication No. 106137481.

[0040] Third, CN Patent Publication No. 106137481 discloses a row of unit rings aligned at an angle θ along a line in a linear design, but the stent has a helical structure such that multiple rows of unit rings are helical along the length of the stent. In contrast, in at least one embodiment, each radial support unit 102 (corresponding to one unit ring) within the radial axial row 120 is aligned in a linear design along a line parallel to the central axis of the stent 100 and thus has no angle or helical structure. In CN Patent Publication No. 106137481, when the stent is bent to move through a blood vessel, it causes a twisting motion, which in turn can cause additional relative motion against the blood vessel wall. In at least one embodiment, the design of the stent 100 ensures that the stent 100 can be easily bent without any twisting motion and minimizes any relative motion against the blood vessel wall.

[0041] These differences in stent design result in different behaviors. In CN Patent Publication No. 106137481, the stent produces similar responses to longitudinal and radial loads, such that multiple rows of unit rings or units are compressed and extended relative to the central axis of the stent. In contrast, at least one embodiment of stent 100 has different responses to longitudinal and radial loads and has an optimized response depending on each situation. Longitudinal loads are typically applied during loading or retraction when the required radial force is low. Radial loads are typically applied after stent 100 reaches its intended treatment position and contacts the vessel wall, at which point the required radial force is high. In at least one embodiment, under a radial load, the vertical struts 110 invert or bend to form a negative vertical strut angle 107, thereby significantly increasing the radial force of the stent. Thus, in at least one embodiment, stent 100 provides a mechanism that provides a high radial force under a radial load and a low radial force under a longitudinal load, while known prior art stents do not distinguish between these two types of loads.

[0042] Each aspect of the present specification may also be described as the following embodiments.

[0043] 1. A stent having a substantially tubular body includes a proximal end and an opposite distal end, and a framework having a plurality of interconnected struts, the plurality of interconnected struts forming a plurality of radial axial columns of radial support units and a plurality of flexible axial columns of flexible support units, the plurality of radial axial columns and the plurality of flexible axial columns being provided in an alternating pattern along the circumferential axis of the stent, each central axis of the radial axial columns and the flexible axial columns being parallel to the longitudinal axis of the stent, each radial axial column being offset along the longitudinal axis of the stent relative to each adjacent radial axial column, and each radial support unit being formed by four struts of the plurality of interconnected struts of the framework, the four struts being arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent.

[0044] 2. According to the stent of Embodiment 1, each flexible support unit is formed by four struts among a plurality of interconnected struts of the skeleton, and the four struts are arranged such that two adjacent flexible axial columns have mirror symmetry along the longitudinal axis of the stent.

[0045] 3. According to the stents of Embodiments 1 and 2, for each radial support unit among the radial support units, the four struts forming the radial support unit are provided such that a pair of opposing vertical struts are oriented substantially perpendicular to the longitudinal axis of the stent.

[0046] 4. According to the stents of Embodiments 1 to 3, the vertical struts of each radial support unit are configured to bend inwardly toward each other when receiving a radial force.

[0047] 5. According to the stents of Embodiments 1 to 4, the vertical struts of each radial support unit are configured to deform from a linear shape to a bent shape having a large radius when the vertical struts receive a radial force.

[0048] 6. According to the stents of Embodiments 1 to 5, when the stent is in a longitudinal restraint configuration, the vertical struts of each radial support unit are configured to deform outwardly from each other when receiving a tension force.

[0049] 7. According to the stents of Embodiments 1 to 6, when the stent is in a longitudinal restraint configuration, the angle between the struts is greater than 0°.

[0050] 8. According to the stents of Embodiments 1 to 7, when the stent is in a longitudinal restraint configuration, the radial force applied by the stent is smaller than the radial force when the stent is in each of the unconstrained configuration and the radial restraint configuration.

[0051] 9. According to the stents of Embodiments 1 to 8, when the stent is in the longitudinal restraint configuration, the radial force applied by the stent allows the stent to be compressed for insertion into the body lumen and loaded into the stent delivery system.

[0052] 10. According to the stents of Embodiments 1 to 9, the stent further includes at least one radiopaque element formed on the stent.

[0053] 11. According to the stents of Embodiments 1 to 10, at least one radiopaque element is positioned at one or both of the proximal end and the distal end of the stent.

[0054] 12. According to the stents of Embodiments 1 to 11, at least one radiopaque element is positioned along the length of the stent.

[0055] 13. According to the stents of Embodiments 1 to 12, 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 an alloy thereof.

[0056] 14. According to the stents of Embodiments 1 to 13, adjacent radial support units are interrupted by a gap therebetween, and the adjacent radial support units are reconnected by a coil spanning the gap therebetween.

[0057] 15. According to the stents of Embodiments 1 to 14, each coil is composed of at least one of a tungsten-containing polymer, platinum, platinum iridium, chromium, cobalt, tantalum, nitinol, nitinol composite, gold, silver, bismuth subcarbonate, barium sulfate, bismuth oxychloride, bismuth trioxide, stainless steel, or an alloy thereof.

[0058] 16. According to the stents of Embodiments 1 to 15, the stent is composed of a single-plate laser-cut material having shape memory characteristics and superelastic characteristics.

[0059] 17. A stent having a substantially tubular body includes a proximal end and an opposite distal end, and a framework having a plurality of interconnected struts, the plurality of interconnected struts forming a plurality of radial axial columns of radial support units and a plurality of flexible axial columns of flexible support units, the plurality of radial axial columns and the plurality of flexible axial columns being provided in an alternating pattern along the circumferential axis of the stent, the central axis of each of the radial axial columns and the flexible axial columns being parallel to the longitudinal axis of the stent, each radial axial column being offset along the longitudinal axis of the stent with respect to each adjacent radial axial column, and each radial support unit being formed by four struts of the plurality of interconnected struts of the framework, the four struts being arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent, each flexible support unit being formed by four struts of the plurality of interconnected struts of the framework, the four struts being arranged such that two adjacent flexible axial columns have mirror symmetry along the longitudinal axis of the stent.

[0060] 18. A stent having a substantially tubular body includes a proximal end and an opposite distal end, a framework having a plurality of interconnected struts, the plurality of interconnected struts forming a plurality of radial axial columns of radial support units and a plurality of flexible axial columns of flexible support units, at least one radiopaque element formed on the stent, the plurality of radial axial columns and the plurality of flexible axial columns being provided in an alternating pattern along the circumferential axis of the stent, the central axis of each of the radial axial columns and the flexible axial columns being parallel to the longitudinal axis of the stent, each radial axial column being offset along the longitudinal axis of the stent with respect to each adjacent radial axial column, and each radial support unit being formed by four struts of the plurality of interconnected struts of the framework, the four struts being arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent.

[0061] Finally, with respect to the exemplary embodiments of the invention shown and described herein, it should be understood that the neurovascular stent is disclosed and configured to have a relatively small profile design that provides a relatively high radial strength without sacrificing flexibility. Since the principles of the invention can be implemented in various configurations other than the ones shown and described, the invention is not limited to the exemplary embodiments in any way, but rather relates generally to neurovascular stents and can be realized in various forms without departing from the spirit and scope of the invention. Those skilled in the art will also understand that the invention is not limited to the specific geometric shapes and structural materials disclosed, and that other functionally equivalent structures or materials now known or later developed can be employed instead without departing from the spirit and scope of the invention.

[0062] This specification describes particular embodiments of the invention, including the best mode known to the inventors for carrying out the invention. It will be apparent to those skilled in the art after reading the foregoing description that variations of these described embodiments will become apparent. The inventors expect those skilled in the art to appropriately employ such variations, and the inventors intend for the invention to be practiced in a manner different from that specifically described herein. Accordingly, the invention includes all modifications and equivalent alternatives of the subject matter recited in the appended claims as permitted by applicable law. The invention also includes any combination of the above embodiments in all possible variations thereof, unless otherwise indicated herein or clearly contradicted by context.

[0063] Groupings of alternative embodiments, elements, or steps of the 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. For convenience and / or reasons of patentability, it can be expected that one or more members of one group may be included in or deleted from that group. If any such inclusion or deletion occurs, this specification is considered to include the group as modified to satisfy the written description of all Markush groups used in the appended claims.

[0064] Unless otherwise specified, all numerical values representing characteristics, items, numbers, parameters, properties, terms, etc. used in this specification and the claims shall be understood to be modified in all cases by the terms "about" and "approximately". As used herein, the terms "about" and "approximately" mean that the defined characteristic, item, number, parameter, property or term is included within a range of plus or minus 10 percent of the value of the above characteristic, item, number, parameter, property or term. Accordingly, unless otherwise indicated, the numerical parameters set forth in the specification and the appended claims are approximate values that can vary. At a minimum, it is not intended to limit the application of the doctrine of equivalents to the claims, and each numerical representation should be construed by applying ordinary rounding techniques based at least on the number of significant digits reported. The numerical ranges and values indicating the broad scope of the present invention are approximate values, but the numerical ranges and values shown in specific examples should be reported as accurately as possible. However, any numerical range or value inherently includes certain errors caused by the standard deviation in their respective test measurements. The recitation of numerical ranges in this specification is intended only as a shorthand method for referring individually to each of the individual numerical values within that range. Unless otherwise indicated herein, each individual value of a numerical range is hereby incorporated into the specification as if it were individually recited herein. Similarly, as used herein, the term "substantially" is a term intended to indicate the degree of approximation of a defined characteristic, item, number, parameter, property or term to the extent understood and interpretable by those skilled in the art and includes the range encompassed thereby, unless otherwise indicated to the contrary.

[0065] When the terms "capable of" or "able to" are used to refer to an embodiment or an aspect of an embodiment, they also have the alternative meaning of "not capable of" or "not able to". Thus, when this specification discloses that an embodiment or an aspect of an embodiment can be included or can be encompassed as part of the subject matter of the present invention, it clearly also means a negative limitation or an exclusionary proviso that the embodiment or the aspect of the embodiment cannot be included or cannot be encompassed as part of the subject matter of the present invention. Similarly, when referring to an embodiment or an aspect of an embodiment, the use of the term "optionally" means that such an embodiment or an aspect of such an embodiment may or may not be included as part of the subject matter of the present invention. Whether such a negative limitation or an exclusionary proviso applies depends on whether this negative limitation or exclusionary proviso is recited in the claimed subject matter.

[0066] Before explaining the elements used in the context of the present invention (in particular, in the context of the following claims), unless otherwise indicated herein or unless clearly inconsistent with the context, quantifiers that are to be construed as including both singular and plural forms are not present. Also, ordinal indicators such as "first", "second", "third", etc. for identifying elements are used to distinguish the elements and, unless otherwise specified, do not indicate or imply a required number or a limited number of such elements, nor do they indicate a particular position or order of such elements. All of the methods described herein can be performed in any suitable order unless otherwise indicated herein or unless clearly inconsistent with the context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein is merely intended to better illustrate the invention and is not intended to limit the scope of the claimed invention. No language in this specification should be construed as indicating any non-claimed element necessary for the practice of the invention.

[0067] When used in the claims, whether in the originally filed claims or claims added in accordance with an amendment, the open transitional term "comprising" (along with its equivalent open transitional phrases such as "including", "containing", and "having") encompasses all expressly recited elements, limitations, steps, and / or features, whether used alone or in connection with other unrecited subject matter. The named elements, limitations, and / or features are essential, but other unrecited elements, limitations, and / or features may also be added, and these unrecited elements, limitations, and / or features can still constitute a structure within the scope of the claims. The specific embodiments disclosed herein may be further limited in the claims by using the closed transitional phrases "consisting of" or "consisting essentially of" in place of or as a modification of "comprising". When used in the claims, whether in the originally filed claims or claims added in accordance with an amendment, the closed transitional phrase "consisting of" excludes any element, limitation, step, or feature not expressly recited in the claim. The closed transitional phrase "consisting essentially of" limits the claim to the expressly recited elements, limitations, steps, and / or features, and any other elements, limitations, steps, and / or features that do not materially affect the basic and novel characteristics of the claimed subject matter. Accordingly, the meaning of the open transitional phrase "comprising" is defined to encompass all specifically recited elements, limitations, steps, and / or features, as well as any additional unrecited elements, limitations, steps, and / or features. The meaning of the closed transitional phrase "consisting of" is defined to include only the elements, limitations, steps, and / or features specifically recited in the claim, and the meaning of the closed transitional phrase "consisting essentially of" is defined to include only the elements, limitations, steps, and / or features specifically recited in the claim and any other elements, limitations, steps, and / or features that do not materially affect the basic and novel characteristics of the claimed subject matter.Accordingly, an open transitional phrase "comprising" (along with its equivalent open transitional phrases) includes within its meaning, when limiting, the claimed subject matter specified by the closed transitional phrases "consisting of" or "consisting essentially of". Accordingly, the embodiments described herein, or claimed embodiments having the phrase "comprising", explicitly or inherently set forth, implement, and support the two phrases "consisting essentially of" and "consisting of".

[0068] Any claim intended to be treated under 35 U.S.C. § 112(f) begins with the term "means for", but the use of the term "for" in any other context is not intended to reference a treatment under 35 U.S.C. § 112(f). Accordingly, Applicant reserves the right to present claims appended hereto in this application or a continuing application after the filing date of this application.

[0069] It should be understood that any method disclosed herein, and the order of corresponding elements for performing any such method, are merely exemplary. Depending on the particular implementation, they may be performed in any order or in parallel, unless otherwise indicated in this disclosure.

[0070] All patents, patent publications, and other publications cited and identified herein are hereby incorporated by reference in their entirety for the purpose of disclosing and describing, for example, the compositions and methods that can be used in combination with the present invention as described in such publications. These publications are provided only because their disclosures predate the filing date of the present application. In this regard, nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention or any other reason. All statements as to the date or content of these documents are based on the information available to the applicant and do not constitute any admission as to the validity of the date or content of these documents.

[0071] While each aspect of the present invention has been described with reference to at least one exemplary embodiment, those skilled in the art should clearly understand that the present invention is not limited thereto. Rather, the scope of the present invention is construed only in relation to the appended claims, and the inventors hereby expressly state that they consider the claimed subject matter to be the present invention.

Claims

1. A stent having a substantially tubular body, a proximal end and an opposite distal end, a framework having a plurality of interconnected struts, the plurality of interconnected struts including a framework forming a plurality of radial axial columns of a radial support unit and a plurality of flexible axial columns of a flexible support unit, the plurality of radial axial columns and the plurality of flexible axial columns being provided in an alternating pattern along the circumferential axis of the stent, the central axis of each of the radial axial columns and the flexible axial columns being parallel to the longitudinal axis of the stent, each radial axial column being offset along the longitudinal axis of the stent with respect to each adjacent radial axial column, each radial support unit being formed by four struts of the plurality of interconnected struts of the framework, the four struts being arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent, a stent.

2. Each flexible support unit is formed by four struts of the plurality of interconnected struts of the framework, the four struts being arranged such that two adjacent flexible axial columns have mirror symmetry along the longitudinal axis of the stent. The stent according to claim 1.

3. For each radial support unit among the radial support units, the four struts forming the radial support unit are provided such that a pair of opposing vertical struts are oriented substantially perpendicular to the longitudinal axis of the stent. The stent according to claim 1.

4. The vertical struts of each radial support unit are configured to bend inwardly towards each other when subjected to a radial force. The stent according to claim 3.

5. The vertical struts of each radial support unit are configured to deform from a straight shape to a curved shape having a large radius when the vertical struts are subjected to a radial force. The stent according to claim 4.

6. When the stent is in a longitudinal restraint configuration, the vertical struts of each radial support unit are configured to deform outwardly from each other when subjected to a tension force. The stent according to claim 3.

7. When the stent is in a longitudinal restraint configuration, the angle between the struts is greater than 0°. The stent according to claim 6.

8. When the stent is in the longitudinal restraint configuration, the radial force applied by the stent is less than the radial forces when the stent is in the unconstrained configuration and the radial restraint configuration, respectively. The stent according to claim 6.

9. When the stent is in the longitudinal restraint configuration, the radial force applied by the stent enables the stent to be compressed for insertion into the body lumen and loaded into the stent delivery system. The stent according to claim 8.

10. Further comprising at least one radiopaque element formed on the stent. The stent according to claim 1.

11. The at least one radiopaque element is positioned at one or both of the proximal end and the distal end of the stent. The stent according to claim 10.

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

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

14. Adjacent radial support units are interrupted by a slit therebetween. Adjacent radial support units are reconnected by a coil spanning the slit therebetween. The stent according to claim 1.

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

16. The stent is composed of a single-sheet laser-cut material having shape memory characteristics and superelastic characteristics. The stent according to claim 1.

17. A stent having a substantially tubular body, a proximal end and an opposite distal end, A framework having a plurality of interconnected struts, wherein the plurality of interconnected struts includes a framework forming a plurality of radial axial columns of a radial support unit and a plurality of flexible axial columns of a flexible support unit, The plurality of radial axial columns and the plurality of flexible axial columns are provided in an alternating pattern along the circumferential axis of the stent, The central axis of each of the radial axial columns and the flexible axial columns is parallel to the longitudinal axis of the stent, Each radial axial column is arranged offset along the longitudinal axis of the stent with respect to each adjacent radial axial column, Each radial support unit is formed by four struts among the plurality of interconnected struts of the framework, and the four struts are arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent, Each flexible support unit is formed by four struts among the plurality of interconnected struts of the framework, and the four struts are arranged such that two adjacent flexible axial columns have mirror symmetry along the longitudinal axis of the stent, Stent.

18. A stent having a substantially tubular body, A proximal end and an opposite distal end, A framework having a plurality of interconnected struts, wherein the plurality of interconnected struts includes a framework forming a plurality of radial axial columns of a radial support unit and a plurality of flexible axial columns of a flexible support unit, At least one radiopaque element formed on the stent, The plurality of radial axial columns and the plurality of flexible axial columns are provided in an alternating pattern along the circumferential axis of the stent, The central axis of each of the radial axial columns and the flexible axial columns is parallel to the longitudinal axis of the stent, Each radial axial column is arranged offset along the longitudinal axis of the stent with respect to each adjacent radial axial column, Each radial support unit is formed by four struts among the plurality of interconnected struts of the framework, and the four struts are arranged symmetrically along both the longitudinal axis and the circumferential axis of the stent, Stent.

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