Double leaf spring stent

Abstract

To provide an expandable stent and a method of using the expandable stent.SOLUTION: The expandable stent comprises a spring structure. The spring structure applies a collapsing radial force in a collapsed state, applies an expanding radial force in an expanded state, and applies a peak radial force during shifting between the collapsed state and the expanded state. The collapsing radial force exceeds the expanding radial force, and the peak radial force exceeds the collapsing radial force and exceeds the expanding radial force.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] FIELD OF THE INVENTION This application relates generally to expandable stents and methods of using expandable stents. [Background technology]

[0002] Shape-changing stents can be used to facilitate surgical procedures within tortuous tissues, such as arteries and / or veins. For example, mechanical thrombectomy for stroke treatment can utilize a stent retriever and aspiration catheter. The stent retriever and aspiration catheter can be deployed within a blood vessel to allow for the aspiration of dangerous material (e.g., thrombus) from a target site. Existing approaches to aspiration-based thrombectomy increase the lumens of the aspiration catheter to improve the success rate of thrombus removal. To increase the lumens of the device, many approaches implement covered stents. For example, a covered self-expanding stent can be delivered to the target site and exposed from a sheath, significantly increasing the lumens of the aspiration device relative to the delivery catheter. After the increase, the lumens can be aspirated into the aspiration device through the expanded stent.

[0003] However, the trade-off between device deliverability and bore size can prevent the effective use of such aspiration devices, for example, in tortuous neurovascular environments. For example, an expandable stent with lower radial force may exhibit greater deliverability through narrow, tortuous spaces. However, a stent with lower radial force may be insufficient to withstand the vacuum pressure generated at the target site by an aspiration device with excessive bore size. Thus, existing approaches still must overcome the challenge of resolving the radial force requirements that enable device deliverability to tortuous target sites, while providing sufficient strength to resist the negative pressure generated at the target site. Summary of the Invention [Problem to be solved by the invention]

[0004] Embodiments of the present disclosure relate to expandable stents, stent kits, and methods of using the stent kits. An exemplary stent of the present disclosure may include a spring structure configured to exert a collapse radial force in a collapsed state, an expansion radial force in an expanded state, and a peak radial force during transition between the collapsed state and the expanded state. The collapse radial force exceeds the expansion radial force. The peak radial force exceeds both the collapse radial force and the expansion radial force. [Means for solving the problem]

[0005] In some embodiments, the spring structure includes a plurality of double leaf springs. In some embodiments, each double leaf spring includes a first curved arm, a second curved arm, a connection between a first end of the first curved arm and a first end of the second curved arm, a first vertical arm connected to the second end of the first curved arm, a second vertical arm connected to the second end of the second curved arm, and a longitudinal member connected to opposing ends of the first vertical arm and the second vertical arm. In some embodiments, each double leaf spring is connected to an adjacent double leaf spring on a first side via the longitudinal member. In some embodiments, the longitudinal member of each double leaf spring is connected to the first vertical arm and the second vertical arm of the adjacent double leaf spring at opposing ends.

[0006] In some embodiments, on a second side opposite the first side, each double leaf spring is connected to an adjacent second double leaf spring via a connection between a first end of the first curved arm and a first end of the second curved arm. In some embodiments, the first curved arm, the second curved arm, the first vertical arm, the second vertical arm, and the longitudinal member are integrally formed. In some embodiments, in the expanded state, the first vertical arm and the second vertical arm are perpendicular to the longitudinal member. In some embodiments, the multiple double leaf springs are integrally formed. In some embodiments, the spring structure comprises Nitinol.

[0007] Another exemplary stent of the present disclosure may include multiple rows of double leaf springs in an annular configuration, each row of double leaf springs including an upper section of the double leaf spring group and a lower section of the double leaf spring group, each double leaf spring in the upper section connected to a corresponding double leaf spring in the lower section, the double leaf springs in each section connected to a first side of a longitudinal member defining the length of each row, and the longitudinal member connected to each double leaf spring in each upper section or lower section of another row of double leaf springs.

[0008] In some embodiments, each dual leaf spring comprises a first curved arm, a second curved arm, a connection between a first end of the first curved arm and a first end of the second curved arm, where the second end of the first curved arm and the second end of the second curved arm define a span of the dual leaf spring, a first vertical arm connected to the second end of the first curved arm, a second vertical arm connected to the second end of the second curved arm, and a respective longitudinal member, where the first vertical arm and the second vertical arm are connected to the longitudinal member at opposite ends of the span.

[0009] In some embodiments, the annular configuration is configured such that the stent transitions between a collapsed state and an expanded state. In some embodiments, in the collapsed state, the angle between each perpendicular arm and the longitudinal member is an obtuse angle. In some embodiments, in the expanded state, the angle between each perpendicular arm and the longitudinal member is a right angle.

[0010] Another exemplary stent of the present disclosure may include a plurality of annular segments, each comprising a plurality of double leaf springs in an annular configuration, each double leaf spring in a first annular segment comprising a first curved arm, a second curved arm, a connection between a first end of the first curved arm and a first end of the second curved arm, where the second end of the first curved arm and the second end of the second curved arm define a span of the double leaf spring, a first vertical arm connected to the second end of the first curved arm, a second vertical arm connected to the second end of the second curved arm, and a respective longitudinal member, wherein the first vertical arm and the second vertical arm are connected to the longitudinal member at opposite ends of the span, and wherein each longitudinal member of the double leaf spring in the first annular segment extends along a remaining subset of the plurality of annular segments, such that a corresponding double leaf spring in the remaining subset is composed in part of the longitudinal member.

[0011] Exemplary stent kits may include one or more stents described herein and shown in the accompanying drawings. In some embodiments, the kits further include respective sheaths configured to cover the stents to maintain the stents in a collapsed state. In some embodiments, the kits include at least one first stent and a second stent, the first stent having a first diameter in an expanded state and the second stent having a second diameter in an expanded state, the second diameter being greater than the first diameter. In some embodiments, each double leaf spring of the first stent has a first thickness and each double leaf spring of the second stent has a second thickness, the second thickness being less than the first thickness. In some embodiments, the kits further include one or more suction devices with respective sheaths and stents.

[0012] An exemplary method for using a stent (or kit) of the present disclosure may include aspirating tubular tissue within a subject. The exemplary method may include guiding a guidewire through the subject and into the tubular tissue; deploying respective sheaths and at least one stent over the guidewire into a target site in the tubular tissue, where the at least one stent is housed in the sheath in a collapsed state; retracting the sheath to transition the at least one stent from the collapsed state to an expanded state, where transitioning the at least one stent to the expanded state expands an inner lumen of the at least one suction device; and aspirating material from the target site via application of negative pressure to the expanded lumen. The material may be a thrombus, a foreign body, or the like.

[0013] In some embodiments, the method includes retracting at least one stent into a sheath to transition the at least one stent to a collapsed state, and transitioning the at least one stent to the collapsed state further includes reducing and transitioning an inner lumen of the suction device, and removing the suction device, the sheath, and the at least one stent from the subject via a guidewire.

[0014] Having thus described embodiments of the present disclosure in general terms, reference is now made to the accompanying drawings, which are not necessarily drawn to scale, and in which: [Brief explanation of the drawings]

[0015] [Figure 1A] FIG. 1 is a right perspective view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 1B] FIG. 1 is a right perspective view of an exemplary stent in a crimped state, according to some embodiments of the present disclosure. [Figure 2A] FIG. 1 is a left perspective view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 2B] FIG. 1 is a left perspective view of an exemplary stent in a collapsed state, according to some embodiments of the present disclosure. [Figure 3A] FIG. 1 is a left side view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 3B] FIG. 1 is a left side view of an exemplary stent in a collapsed state, according to some embodiments of the present disclosure. [Figure 4A] FIG. 1 is a right side view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 4B] FIG. 1 is a right side view of an exemplary stent in a crimped state, according to some embodiments of the present disclosure. [Figure 5A] 1A and 1B are top views of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 5B] FIG. 1 illustrates a top view of an exemplary stent in a crimped state, according to some embodiments of the present disclosure. [Figure 6A] FIG. 1 is a bottom view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 6B] FIG. 1B is a bottom view of an exemplary stent in a collapsed state, according to some embodiments of the present disclosure. [Figure 7A] FIG. 1 is a front view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 7B] FIG. 1 is a front view of an exemplary stent in a crimped state, according to some embodiments of the present disclosure. [Figure 8A] FIG. 1 is a rear view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 8B] FIG. 1 is a rear view of an exemplary stent in a crimped state, according to some embodiments of the present disclosure. [Figure 9] 1A-1C are diagrams of an exemplary double leaf spring, according to some embodiments of the present disclosure. [Figure 10] 10A-10C illustrate a transition sequence between an expanded state and a collapsed state of an exemplary dual leaf spring, according to some embodiments of the present disclosure. [Figure 11]1A-1C are diagrams of exemplary radial force-diameter relationship charts for a conventional stent and a double leaf spring, according to some embodiments of the present disclosure. [Figure 12] 1A-1C are diagrams of exemplary variations of a traditional leaf spring stent and a dual leaf spring stent, according to some embodiments of the present disclosure. [Figure 13] FIG. 1 is a right perspective view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 14] FIG. 1 is a left perspective view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 15] FIG. 1 is a left side view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 16] FIG. 1 is a right side view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 17A] 1A and 1B are top views of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 17B] FIG. 1 is a bottom view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 18A] FIG. 1 is a front view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 18B] FIG. 1 is a rear view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 19] FIG. 1 is a right perspective view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 20] FIG. 1 is a left perspective view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 21A] FIG. 1 is a left side view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 21B] FIG. 1 is a right side view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 22A] 1A and 1B are top views of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 22B] FIG. 1 is a bottom view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 23A] FIG. 1 is a front view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 23B] FIG. 1 is a rear view of an exemplary stent in an expanded state, according to some embodiments of the present disclosure. [Figure 24] 10 is a flowchart of an exemplary aspiration process according to various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] Certain embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Like reference numerals refer to like elements throughout the drawings. Indeed, various embodiments of the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

[0017] As used herein, the term "or" is used in both the alternative and connective sense unless otherwise indicated. The term "along" and similarly used terms mean near or on the edge or other location referenced, but not necessarily directly on the edge or other location referenced. The terms "about," "generally," and "substantially" refer to within manufacturing and / or engineering design tolerances for corresponding materials and / or elements, unless otherwise indicated. Therefore, use of any such above-mentioned terms or similarly interchangeable terms should not be construed as limiting the spirit and scope of embodiments of the present invention.

[0018] As used herein, reference is made to a dual leaf spring stent for use with a suction device. However, the present disclosure contemplates that the dual leaf spring stent of the present disclosure may be equally applicable to other applications where reduced radial forces in the expanded state of the stent are advantageous. For example, the dual leaf spring stent may be used in other thrombectomy procedures, stent retrieval procedures, angioplasty procedures, ureteral procedures, and / or aneurysm interventions, etc.

[0019] overview Generally, various embodiments of the present disclosure provide improved designs for self-expanding stents. For example, the present disclosure provides various embodiments of a self-expanding dual leaf spring stent for use in aspiration thrombectomy procedures. It is understood and appreciated that such context is provided by way of example, and that use of the stent in additional contexts, such as use in other medical procedures, is contemplated and within the scope of the present invention.

[0020] As described above, existing stents for suction thrombectomy face the challenge of over-expanding the suction device lumen and resisting negative pressure while providing sufficient radial force at the target site to maintain the suction device's maneuverability through tortuous tissue within the body. For example, achieving a significant increase in the suction lumen diameter may reduce the device's ability to navigate through small blood vessels and other tubular structures within the body. The use of a self-expanding covered stent with a weaker radial force may reduce the device's spatial profile and increase its deliverability. For example, during device delivery, less friction between the sheath and the stent may be beneficial because a lower radial force is favorable over a higher stent radial force. However, a higher stent radial force may be preferable at the delivery target site to allow the stent to withstand the high negative pressure generated by the suction device.

[0021] Other approaches to stent expansion rely on balloon catheters. For example, stainless steel stents can be expanded via inflation of a balloon catheter. However, such approaches can permanently deform the stent, resulting in the need for an additional mechanism to recompress the stent for removal, further increasing the complexity and bulk of the aspiration device. Therefore, self-expanding stents may be preferable for use in aspiration thrombectomy. However, challenges exist in balancing the radial forces on the stent and achieving sufficiently low friction while delivering the aspiration device, while still allowing the stent to maintain its ability to over-expand the aspiration lumen and withstand the negative pressure used in the procedure.

[0022] To address these and other concerns, exemplary implementations of the present application may provide a dual leaf spring stent that provides reduced radial force when the stent is configured in a collapsed state during the device delivery phase and maintains a sufficiently strong radial force when the stent is configured in an expanded state during the aspiration phase. In various embodiments, the dual leaf spring stent includes a novel spring configuration to achieve the reduced radial force during compression. For example, conventional self-expanding stents exhibit a peak radial force when in a compressed state. In contrast, the dual leaf spring stent of the present invention exhibits a peak transitional radial force during transition to the compressed state. For example, the compressive radial force exerted by the dual leaf spring stent when configured in a compressed state is less than the peak transitional radial force reached during transition to the compressed state. In various embodiments, the novel spring configuration includes a combination of two leaf springs, referred to herein as a "curved arm" and a "vertical arm." In some embodiments, the curved arms embody the "weaker springs" and the vertical arms embody the "stronger springs." In various embodiments, stent compression initially deforms both the "weaker leaf springs" (curved arms) and the "stronger leaf springs" (vertical arms). Then, further compression relaxes only the "stronger leaf springs," reducing the radial force.

[0023] Thus, the dual leaf spring stents described below improve the deliverability of aspiration devices by providing reduced radial force when compressed while maintaining sufficient radial force when expanded. The reduced radial force may result in lower friction between the aspiration device and the walls of tortuous tissue through which the aspiration device is inserted. Furthermore, the dual leaf spring structure maintains sufficient internal space when compressed to allow the aspiration device membrane to relax, further increasing the maneuverability of the aspiration device through tortuous paths. In various embodiments, the reduced radial force of a compressed dual leaf spring stent allows the stent (and the aspiration device housing the stent) to be delivered via a pushing means, which is advantageous over a pulling means, which involves additional mechanical complexity and bulk.

[0024] Exemplary Double Leaf Spring Stent Referring to FIG. 1A, a right perspective view of an exemplary stent 100A in an expanded state is shown. In some embodiments, stent 100A includes a spring structure 101A configured to transition between an expanded state (e.g., as shown in FIG. 1A) and a collapsed state (e.g., as shown in spring structure 101B of FIG. 1B). In some embodiments, spring structure 101A is configured to exert an expanding radial force in the expanded state and a collapsing radial force in the collapsed state. In some embodiments, the collapsing radial force exceeds the expanding radial force. In various embodiments, spring structure 101A is configured to exert a peak radial force during the transition between the collapsed state and the expanded state, the peak radial force exceeding the collapsing radial force and exceeding the expanding radial force.

[0025] In some embodiments, spring structure 101A comprises nitinol and / or one or more nitinol-containing alloys, etc. Additionally or alternatively, in some embodiments, spring structure 101A comprises cupro-nickel-aluminum alloy, silicomanganese alloy, and / or cupro-zinc-aluminum alloy, etc. In some embodiments, spring structure 101A comprises one or more radiopaque materials to increase the visibility of stent 100A under one or more radiographic imaging modes.

[0026] In some embodiments, the spring structure 101A includes a plurality of dual leaf springs 103A. In some embodiments, the dual leaf springs are interconnected in an annular configuration. In some embodiments, each dual leaf spring includes a first curved arm 105, a second curved arm 106, a first vertical arm 107, a second vertical arm 108, and a longitudinal member 109. In some embodiments, a first side of the dual leaf spring 103A includes the first curved arm 105 and the first vertical arm 107. In some embodiments, on a second side opposite the first side, the dual leaf spring 103A includes the second curved arm 106 and the second vertical arm 108. In various embodiments, the elements of the dual leaf spring 103A are integrally formed. For example, the first curved arm 105, the second curved arm 106, the first vertical arm 107, the second vertical arm 108, and the longitudinal member 109 may be integrally formed with one another. Furthermore, in some embodiments, the multiple double springs 103A embodying the spring structure 101A are integrally formed.

[0027] In various embodiments, the dual leaf spring 103A includes a connection 104 between the first curved arm 105 and the second curved arm 106. In some embodiments, the connection 104 includes a first side to which the first curved arm 105 and the second curved arm 106 of the first dual leaf spring are connected. In some embodiments, the connection 104 includes a second side opposite the first side to which the first curved arm 105 and the second curved arm 106 of the second dual leaf spring are connected.

[0028] In some embodiments, the first curved arm 105 is connected to a first end of the first vertical arm 107. In some embodiments, on a second end opposite the first end, the first vertical arm 107 is connected to a first end of the longitudinal member 109. In some embodiments, the second curved arm 106 is connected to a first end of the second vertical arm 108. In some embodiments, on a second end opposite the first end, the second vertical arm 108 is connected to a second end of the longitudinal member 109 (e.g., the end opposite the first end of the longitudinal member). In various embodiments, each curved arm defines a transverse leaf spring with a variable bending portion. The variable bending portion may include multiple concave and convex portions (e.g., multiple arc portions).

[0029] In various embodiments, at a first end (e.g., at connection 104), each curved arm comprises a first concave portion. In some embodiments, adjacent to the first concave portion, the curved arm comprises a first convex portion. In some embodiments, adjacent to the first convex portion, the curved arm comprises a second concave portion. In some embodiments, adjacent to the second concave portion, the curved arm comprises a second convex portion. The second convex portion may embody a connection between the curved arm and the respective vertical arm. In some embodiments, the arms are straight in the expanded state.

[0030] In some embodiments, in the expanded state, each vertical arm is oriented perpendicular to longitudinal member 109. For example, while spring structure 101A is configured in the expanded state, each angle between longitudinal member 109 and each of first vertical arm 107 and second vertical arm 108 can be a right angle (e.g., about 90 degrees). In some embodiments, each longitudinal member is connected to a first vertical arm and a second vertical arm of a first double leaf spring on a first side. In some embodiments, longitudinal member 109 is further connected to a first vertical arm and a second vertical arm of a second double leaf spring on a second side opposite the first side.

[0031] FIG. 1B shows a right perspective view of exemplary stent 100B in a collapsed state. In various embodiments, stent 100B embodies stent 100A transitioned from the expanded state shown in FIG. 1A to a compressed state. For example, spring structure 101B may embody contracted spring structure 101A. The outward radial force exerted by spring structure 101B may exceed the outward radial force exerted by spring structure 101A (e.g., the radial forces may be referred to as a contracted radial force and an expanded radial force, respectively). Dual leaf spring 103B may embody a collapsed dual leaf spring 103A.

[0032] In some embodiments, in the collapsed state, the first curved arm 105' and the second curved arm 106' of the dual leaf spring 103B are deflected toward the longitudinal member 109' relative to the orientation shown in FIG. 1A and further shown in FIG. 10. In some embodiments, in the collapsed state, one or more portions of the first vertical arm 107' and the second vertical arm 108' are deflected outward relative to the orientation shown in FIG. 1A and FIG. 9. In various embodiments, the deflection of the first curved arm and the second curved arm, respectively, toward the longitudinal member and the outward deflection of the first vertical arm and the second vertical arm are shown in FIG. 10 and further illustrated in an example transition sequence 1000 described herein.

[0033] In some embodiments, during transition between the collapsed and expanded states, the longitudinal members resist deflection of the first and second curved arms 105' and 106' and the first and second vertical arms 107' and 108', respectively. For example, stent 100A may transition to the configuration embodied as stent 100B via retraction of the stent into a sheath that applies an inward radial force, causing the spring structures to collapse from the expanded state to the collapsed state. The inward radial force may cause deflection of the curved arms of the double leaf spring comprising the spring structure, the deflection being movement toward the respective longitudinal members of the corresponding double leaf spring. In such a context, at the respective connections between the longitudinal member 109 and the first vertical arm 107′ and between the first vertical arm 107′ and the first curved arm 105′, the longitudinal member 109 may restrain the first curved arm 105′ from deflecting to a maximum angle that would cause further compressive force to cause outward deflection of the first vertical arm 107′ (as opposed to, e.g., causing further deflection of the first curved arm 105′ toward the longitudinal member 109′ beyond the maximum angle). By doing so, the stents 100A,B may exhibit a nonlinear trend in the outward radial force exerted by the spring structures while transitioning between the expanded and collapsed states.

[0034] For example, as further shown in chart 1100 of Figure 11, a typical self-expanding stent may exhibit a linear relationship between applied outward radial force and stent diameter. In contrast, stents 100A, 100B (and other dual leaf spring stents of the present disclosure, for example) may exhibit a non-linear relationship between applied outward radial force and stent diameter.

[0035] FIG. 2A shows a left perspective view of an exemplary stent 100A in an expanded state. FIG. 2B shows a left perspective view of an exemplary stent 100B in a collapsed state. As shown, the spring structure 101A includes a plurality of dual leaf springs 103A in an annular configuration. In various embodiments, adjacent dual leaf springs are connected via longitudinal members 109 or connectors 104. In some embodiments, the dual leaf springs embodying the spring structure are integrally formed. For example, on a first side, a first dual leaf spring 103A can be connected to a second dual leaf spring 103A via a common longitudinal member 109. On a second side of the first dual leaf spring 103A, the first dual leaf spring 103A can be connected to a third dual leaf spring 103A via connectors 104. The second double leaf spring 103A may be further connected to a fourth double leaf spring 103A via another connection 104, and the third double leaf spring 103A may be further connected to a fifth double leaf spring 103A via another common longitudinal member 109. The spring structure 101A may include several more double leaf springs connected in a circular sequence such that the spring structure has a substantially ring shape. For example, the spring structure 101A may include 12 double leaf springs connected to each other in a circular sequence.

[0036] Figure 3A shows a left side view of exemplary stent 100A in an expanded state. Figure 3B shows a left side view of exemplary stent 100B in a collapsed state. As shown, stents 100A, 100B have a first diameter 301 and width in the expanded state and a second diameter 303 in the collapsed state. In some embodiments, second diameter 303 is smaller than first diameter 301. In various embodiments, stents 100A, 100B have lengths 305, 305' that remain constant in the collapsed and expanded states.

[0037] Figure 4A shows a right side view of an exemplary stent in an expanded state, and Figure 4B shows a right side view of an exemplary stent 100B in a collapsed state.

[0038] Figure 5A shows a top view of an exemplary stent 100A in an expanded state, and Figure 5B shows a top view of an exemplary stent 100B in a collapsed state.

[0039] Figure 6A shows a bottom view of an exemplary stent 100A in an expanded state, and Figure 6B shows a bottom view of an exemplary stent 100B in a collapsed state, according to some embodiments of the present disclosure.

[0040] Figure 7A shows a front view of an exemplary stent 100A in an expanded state, and Figure 7B shows a front view of an exemplary stent 100B in a collapsed state.

[0041] Figure 8A shows a rear view of an exemplary stent 100A in an expanded state, and Figure 8B shows a rear view of an exemplary stent 100B in a collapsed state.

[0042] FIG. 9 illustrates an exemplary dual leaf spring 103. In various embodiments, FIG. 9 illustrates the dual leaf spring 103 in an expanded state. The dual leaf springs described herein can include a first curved arm 105, a second curved arm 106, a first vertical arm 107, a second vertical arm 108, and a longitudinal member 109. In some embodiments, each curved arm includes a first end 901 and a second end 903 opposite the first end 901. For example, each curved arm extends from the first end 901 of the curved arm to the second end of the curved arm. In various embodiments, the first ends 901 of the first curved arm 105 and the second curved arm 106 are connected, and the connection is referred to herein and in the accompanying drawings as a connection 104. In some embodiments, each vertical arm includes a first end 905 and a second end 907 opposite the first end 905. For example, each vertical arm extends from a vertical arm first end 905 to a vertical arm second end 907. In various embodiments, each curved arm is connected to the vertical arm first end 905 at its second end 903. For example, the first curved arm 105 is connected to the first end 905 of the first vertical arm 107 at its second end 903.

[0043] In some embodiments, the longitudinal member 109 includes a first end 909 and a second end 911 opposite the first end 909. For example, the longitudinal member 109 extends from the first end 909 of the longitudinal member 109 to the second end 911 of the longitudinal member 109. In some embodiments, the longitudinal member includes a first side 913 and a second side 915 opposite the first side 913. In some embodiments, the second end 907 of the first vertical arm 107 is connected to the first end 909 of the longitudinal member 109 on the first side 913. In some embodiments, the second end 907 of the second arm 108 is connected to the second end 911 of the longitudinal member 109 on the first side 913. In various embodiments, the first and second vertical arms of adjacent double leaf springs (not shown) are connected to the first end 909 and the second end 911, respectively, on the second side 915 of the longitudinal member 109. For example, the first vertical arm 107 of a pair of adjacent double leaf springs may form a T-shaped joint with the first end 909 of the longitudinal member 109, and the second vertical arm 108 of a pair of adjacent double leaf springs may form a T-shaped joint with the second end 911 of the longitudinal member 109. In some embodiments, the first curved arm of another adjacent double leaf spring (not shown) is connected to the connector 104.

[0044] 10 illustrates a transition sequence 1000 between the expanded and collapsed states of an exemplary dual leaf spring. In various embodiments, the transition sequence 1000 includes an expanded state 1001, an intermediate state 1003, and a collapsed state 1005, with the intermediate state occurring between the expanded state 1001 and the collapsed state 1005. In some embodiments, each dual leaf spring is configured to the collapsed state 1005 when covered by a sheath and / or within the catheter of the aspiration device. In some embodiments, upon retraction of the sheath and / or exiting the catheter, the dual leaf spring is automatically configured to the intermediate state 1003 and ultimately to the expanded state 1001. In some embodiments, the dual leaf spring is mechanically biased toward configuration to the expanded state 1001.

[0045] As described and illustrated herein, the self-expanding stent of the present disclosure may include a repeating pattern of leaf spring elements. A conventional self-expanding stent may expand linearly, or the elements of the stent may act as a typical leaf spring. In contrast, the stent elements, including the curved arms 105, the vertical arms 107, and the longitudinal members 109, may exhibit inherent nonlinearity. Due to symmetry and repetition, the mechanical performance of the stent may be determined and designed from these basic spring elements. As a conventional stent is subjected to compressive forces from either the vessel wall, negative vacuum pressure, or a crimping device, the bending action of the leaf springs will exhibit a gradual, constant increase in radial force (e.g., as shown by trend 1107 in FIG. 11 ). In contrast, with the dual leaf spring of the present disclosure, the radial force will increase, peak, and decrease fairly quickly (e.g., as shown by trend 1105 in FIG. 11 ). This nonlinearity is achieved by the combination of the three spring elements (e.g., the curved arms, the vertical arms, and the longitudinal members). In various embodiments, as the curved arm is displaced, it pushes the other vertical spring element sideways (eg, as shown in intermediate state 1003).

[0046] In some contexts, the curved arms embody "weaker leaf springs" and the vertical arms embody "stronger leaf springs." When transitioning from the extended state 1001 to the intermediate state 1003, the forces of the curved arms and the vertical arms may add. For example, the curved arms may deflect toward the longitudinal members and the vertical arms may deflect outward. When the displacement (e.g., deflection) of the curved arms exceeds a certain point (e.g., the intermediate state 1003), the curved arms begin to pull the vertical arms back (e.g., the collapsed state 1005). Here, some of the forces of the two arms are "decreased." For example, the curved arms deflect further toward the longitudinal members and the vertical arms deflect inward relative to their orientation in the intermediate state 1003. This initial additional compression generates a high spring force in the extended state 1001, and the subsequent reduced tension achieves a relatively low spring force in the collapsed state 1005 (e.g., compared to existing approaches). The movement of the curved and vertical arms is supported by a longitudinal spine, and the length of the vertical arms provides space for the leaf springs to move and accommodate sufficient difference in maximum and minimum diameter of the dual leaf spring stent, which can determine the diameter of the sheath that delivers the stent and the diameter of the stent after deployment from the sheath.

[0047] In some embodiments, in the expanded state 1001, the angle 1006 between the first curved arm 105 and the first vertical arm 107 is a right angle. For example, in the expanded state 1001, the first curved arm 105 and the first vertical arm 107 are perpendicular to one another. In some embodiments, in the expanded state 1001, the angle 1008 between the first vertical arm 107 and the longitudinal member 109 is a right angle (e.g., approximately 90 degrees). Similarly, in the expanded state, the second curved arm 106 and the second vertical arm 108 are perpendicular to one another. It should be understood that the above and preceding descriptions of the angle between the first curved arm and the first vertical arm, and the angle between the first vertical arm and the longitudinal member, may also refer to the angular relationship between the second curved arm and the second vertical arm, and the angular relationship between the second vertical arm and the longitudinal member. For example, although not shown in FIG. 10, the angle between the second curved arm and the second vertical arm can be a right angle when the dual leaf spring is configured in the expanded state 1001.

[0048] In some embodiments, an externally applied force (e.g., a sheath and / or catheter) transitions the dual leaf spring from the expanded state 1001 to the intermediate state 1003. For example, a dual leaf spring stent may be inserted into a sheath that constrains the dual leaf spring, thereby applying a force to each dual leaf spring of the stent, causing it to transition from the expanded state 1001 to the intermediate state 1003 and from the intermediate state 1003 to the collapsed state 1005. Additionally or alternatively, in some embodiments, a decrease in the temperature of the dual leaf spring may cause one or more shape memory alloys (SMAs) comprising the springs to become deformable, thereby facilitating the collapse of the springs from the expanded state. For example, the alloy or alloys from which the stent is fabricated may be designed to cause the stent to contract prior to introduction into the body, with body heat expanding the stent after insertion.

[0049] In some embodiments, in the intermediate state 1003, the curved arm 105' deflects toward the longitudinal member 109'. The deflection of the curved arm 105' may increase internal stresses within the first curved arm 105' and at the connection to the first vertical arm 107' and the second curved arm (not shown), causing the first curved arm 105' to apply a spring force (embodied as a radial force when multiple double leaf springs are fabricated in an annular configuration). In some embodiments, in the intermediate state 1003, the first vertical arm 107' deflects outward under an external force (and / or a translation force applied by the first curved arm 105'). In some embodiments, the outward deflection of the first vertical arm 107' at least partially dissipates the internal stresses within the first curved arm 105', causing the spring force applied by the spring configuration to be reduced to a peak value.

[0050] In various embodiments, in the intermediate state 1003 and the folded state 1005, the longitudinal members 109′, 109″ constrain deflection of the first curved arm 105′, 105″ and the first vertical arm 107′, 107″, causing the dual leaf spring to assume a non-linear profile when a spring force is applied by the spring configuration of the first curved arm and the first vertical arm. In some embodiments, in the folded state 1005, the first curved arm 105″ deflects further toward the longitudinal member 109″. In some embodiments, as the dual leaf spring transitions from the intermediate state 1003 to the folded state 1005, the spring force applied by the first curved arm 105″ is lower than the peak value associated with the spring configuration of the intermediate state (e.g., while still exceeding the value associated with the spring configuration of the expanded state 1001). In some embodiments, the first vertical arm 107'' is deflected inward relative to the orientation shown in the intermediate state 1003. In some embodiments, in the folded state 1005, the angle 1006' between the first curved arm 105'' and the first vertical arm 107'' is an acute angle. In some embodiments, in the folded state 1005, the angle 1008' between the first vertical arm 107'' and the longitudinal member 109'' is an obtuse angle.

[0051] FIG. 11 shows an exemplary radial force-diameter relationship chart 1100 for a conventional stent and a dual leaf spring stent of the present disclosure. In some embodiments, the chart 1100 measures the radial force 1101 exerted by the stent as a function of the stent diameter 1103. In various embodiments, the trend 1107 is associated with a conventional self-expanding stent, such as a self-expanding stent composed of independent (e.g., non-dual) leaf springs. As shown by the trend 1107, a conventional self-expanding stent may exhibit a linear relationship between the stent diameter 1103 and the applied radial force 1101 between the collapsed state 1005, the intermediate state 1003, and the expanded state 1001. For example, a conventional self-expanding stent may exhibit a linear increase in the applied radial force 1101 as the stent diameter 1103 decreases. Furthermore, a conventional self-expanding stent may exhibit a maximum applied radial force 1111 when configured to its smallest stent diameter.

[0052] As shown by trend 1105, the dual leaf spring stent of the present disclosure may exhibit a nonlinear relationship between stent diameter 1103 and applied radial force 1101. For example, the dual leaf spring may exhibit a nonlinear increase in applied radial force between the expanded state 1001 and the intermediate state 1003. As another example, the dual leaf spring may exhibit a nonlinear decrease in applied radial force between the intermediate state 1003 and the collapsed state 1005. Furthermore, the dual leaf spring of the present disclosure may exhibit a maximum applied radial force 1109 when configured to an intermediate stent diameter (e.g., intermediate state 1003). Compared to conventional self-expanding stents, the dual leaf spring stent of the present disclosure exhibits a low radial force when the stent is collapsed and a high radial force when the stent is expanded. When a dual leaf spring stent is collapsed from an expanded state, compression of the stent first deforms both the "weaker leaf spring" (e.g., the curved arms) and the "stronger leaf spring" (e.g., the vertical arms). Further compression then relaxes only the "stronger leaf spring," reducing the radial force.

[0053] In some embodiments, the maximum applied radial force 1109 is referred to herein as the peak radial force, and the peak radial force occurs while the dual leaf spring structure transitions between the expanded state 1001 and the collapsed state 1005. In some embodiments, in the expanded state 1001, the spring structure exerts an expansion radial force 1113. In some embodiments, in the collapsed state 1005, the spring structure exerts a collapse radial force 1115. In some embodiments, the expansion radial force 1113 is less than the collapse radial force 1115. In various embodiments, the peak radial force exceeds the expansion radial force 1113 and exceeds the collapse radial force 1115.

[0054] FIG. 12 shows exemplary variations of a conventional leaf spring stent and a dual leaf spring stent of the present disclosure. In various embodiments, the dual leaf spring stent design of the present invention provides advantages when a covered stent is used with this stent structure. FIG. 12 presents a comparison of a conventional stent variation 1301 and a dual leaf spring stent variation 1203, where the same displacement reduces the stent diameter. In the case of a conventional stent, as the stent diameter decreases, the radial force exhibits an inflection point where the radial force rapidly increases. At this inflection point, the membrane is "pinched" by the stent struts, and compression of the membrane exerts excessive radial force, making delivery of the covered stent difficult. To overcome this deficiency, the dual leaf spring stent of the present invention reduces this radial force and provides sufficient room for the membrane, allowing it to maintain some slack or relax while in a sheath-catheter. For example, in the case of a nonlinear dual leaf spring stent, the lower portion 1205, 1205' of the structure does not deform, thereby providing ample room for the membrane during stent diameter reduction. Thus, the inflection point can be well below the diameter the stent will have while in the sheath-catheter. In this way, the dual leaf spring stent of the present invention provides the added benefit of a relaxed membrane, further contributing to lower radial forces during delivery.

[0055] FIG. 13 shows a right perspective view of exemplary stent 1300 in an expanded state. It should be understood that the above description of stents 100A and 100B may apply to stents 1300, 1900, and similarly named elements. In various embodiments, stent 1300 comprises multiple annular segments, each comprising multiple double leaf springs in an annular configuration. For example, first annular segment 1301A may include multiple double leaf springs 103A-L interconnected in an annular configuration. In some embodiments, the annular segments of stent 1300 are interconnected such that the stent is expandable and collapsible through uniform deformation of the annular segments. As an example, first annular segment 1301A may connect to a first side of second annular segment 1301B. A second side of the second annular section 1301B may connect to a third annular section 1301C, and additional annular sections may similarly connect to the third annular section and each other.

[0056] In various embodiments, each annular segment is connected to one another via a longitudinal member of a dual leaf spring comprising multiple segments. For example, as shown in the left perspective view of FIG. 14, a first annular segment 1301A can be connected to a second annular segment 1301B via longitudinal members 109A-F, which extend from the first plurality of dual leaf springs comprising the first annular segment 1301A to the second plurality of dual leaf springs comprising the second annular segment 1301B. In various embodiments, the longitudinal members 109A-F extend further along the length 1401 of the stent 1300, such that subsequent segments of the dual leaf springs comprise respective portions of the longitudinal members 109A-F and are connected via the longitudinal members 109A-F.

[0057] In some embodiments, the connected portions of the annular sections define rows of dual leaf springs. For example, the stent 1300 can include multiple interconnected rows of dual leaf springs in an annular configuration. As shown in the left side view of FIG. 15 , each row 1501 of dual leaf springs can include an upper section 1503 of the dual leaf springs and a lower section 1505 of the dual leaf springs. In some embodiments, each dual leaf spring 1507 in the upper section 1503 is connected to an adjacent dual leaf spring 1509 in the lower section 1505. In some embodiments, adjacent dual leaf springs in each of the upper and lower sections 1503, 1505 are connected via connections 104 between curved arms 105A, B, 106A, B of the dual leaf springs.

[0058] In some embodiments, the double leaf springs in each section are connected to a first side of the longitudinal member, which defines the length of the row of double leaf springs. For example, the double leaf springs in the upper section 1503 may be connected to a first side of the longitudinal member 109A. The double leaf springs comprising the lower sections of adjacent rows may be connected to a second side of the longitudinal member 109A, opposite the first side. As another example, the double leaf springs in the lower section 1505 may be connected to a first side of the longitudinal member 109B. In various embodiments, each connection comprises the longitudinal member, the first vertical arm, and the second vertical arm of the respective double leaf spring. For example, the second ends 903A, 903B of the curved arms of the double leaf spring may define the span 1511 of the double leaf spring. Furthermore, the span 1511 may define the span of the longitudinal member 109B comprising a portion of the double leaf spring. The first and second vertical arms of the double leaf spring may connect to longitudinal member 109B at opposite ends of span 1511.

[0059] FIG. 16 shows a right side view of an exemplary stent 1300 in an expanded state.

[0060] 17A-17B show top and bottom views, respectively, of exemplary stents 1300A, 1300B in an expanded state.

[0061] 18A-18B show front and back views, respectively, of exemplary stents 1300A, 1300B in an expanded state.

[0062] FIG. 19 shows a right perspective view of an exemplary stent 1900 in an expanded state.

[0063] FIG. 20 shows a left perspective view of an exemplary stent 1900 in an expanded state.

[0064] 21A-21B show left and right side views, respectively, of exemplary stents 1900A, 1900B in an expanded state.

[0065] 22A-22B show top and bottom views, respectively, of exemplary stents 1900A, 1900B in an expanded state.

[0066] 23A-23B show front and back views, respectively, of exemplary stents 1900A, 1900B in an expanded state.

[0067] Example Uses Having described exemplary expandable stents according to the present disclosure, exemplary processes of the present disclosure will now be described. It should be understood that the flowcharts illustrate exemplary processes that can be performed using one or more expandable stents described herein. For example, the aspiration process 2400 illustrated in the flowchart of FIG. 24 and described herein may be performed using one or more stents 100A, 100B, 1300, 1800 shown in FIGS. 1A-1B, 13, and 19, respectively, and described herein. In some embodiments, one or more processes are performed using a kit including one or more stents. For example, the aspiration process 2400 may be performed using a kit including one or more stents 100A, 100B, 1300, and / or 1900, etc. In some embodiments, the kit further includes one or more sheaths configured to cover the respective stents to maintain the stents in a collapsed state, and retraction of the sheaths causes the stents to transition from the collapsed state to the expanded state.

[0068] In some embodiments, the kit includes at least a first stent and a second stent. The first stent can have a first diameter in an expanded state, and the second stent can have a second diameter in an expanded state. The second diameter can be less than, equal to, or greater than the first diameter. Additionally or alternatively, in some embodiments, the one or more dual leaf springs of the first stent have a first thickness, and the one or more dual leaf springs of the second stent have a second thickness. In various embodiments, the second thickness is less than, greater than, or equal to the first thickness.

[0069] In some embodiments, the kit includes one or more suction devices with respective stents and sheaths. In some embodiments, the kit includes one or more sterile covers configured to receive one or more kit components and to provide a barrier between an interior cavity of the cover and the external environment.

[0070] The illustrated blocks represent the operations of each process. Such operations may be performed in any of several ways, including, but not limited to, in the order and manner shown and described herein. In some embodiments, one or more blocks of any of the processes described herein occur between one or more blocks of another process, before one or more blocks of another process, simultaneously with one or more blocks of another process, and / or as a sub-step of a second process. Additionally or alternatively, any of the processes of various embodiments may include some or all of the operational steps described and / or shown, including one or more operational blocks in some embodiments. With respect to the flowcharts shown herein, one or more of the blocks shown in some embodiments are optional in some or all embodiments of the present disclosure. It should be understood that one or more of the operations of each flowchart may be combined and substituted and / or altered in other ways described herein.

[0071] 24 shows a flowchart illustrating operations of an exemplary process 2400 for aspirating material from a target site within a tubular tissue. For example, process 2400 may be performed to aspirate a thrombus from a target site, such as within a vein and / or artery (e.g., thrombectomy). As another example, process 2400 may be performed to aspirate atheroma from a target site (e.g., atherectomy).

[0072] In some embodiments, process 2400 includes directing a guidewire into the tubular tissue of the subject at block 2403. For example, the guidewire may be inserted into an artery of the subject through an incision and directed through the artery of the subject to a particular segment of the artery or a second blood vessel (e.g., another artery, and / or vein, etc.).

[0073] In some embodiments, at block 2406, process 2400 includes deploying a suction device at a target site within the tubular tissue over a guidewire. In some embodiments, the suction device includes an expandable catheter and a self-expanding double leaf spring stent within the catheter, the self-expanding double leaf spring stent being covered by a retractable sheath. In some embodiments, the double leaf spring stent is configured to be maintained in a collapsed state via a sheath cover. In some embodiments, the suction device is deployed at the target site by advancing the expandable catheter along the guidewire to a particular portion within the tubular tissue that embodies the target site. In some embodiments, the suction device includes a suction catheter operably connected to a pump system or the like that generates negative pressure within the suction device, allowing material to be aspirated into the suction catheter.

[0074] As described herein, in a collapsed state, a dual leaf spring stent can exhibit reduced radial force compared to typical stents used to perform aspiration thrombectomy. In various embodiments, the reduced radial force reduces friction of the aspiration device against the target tubular tissue. The reduced friction can improve the safety and deliverability of the aspiration device compared to existing techniques. For example, the reduced friction can increase the maneuverability of the aspiration device through a blood vessel. As another example, the reduced friction can reduce the propulsive force required to advance the aspiration device, thereby reducing the likelihood of perforating or otherwise damaging the target tissue.

[0075] In some embodiments, in block 2409, process 2400 includes transitioning each dual leaf spring stent of the suction device from a constrained state to an expanded state. In some embodiments, the subject's body heat transfers thermal energy to one or more shape memory materials comprising the dual leaf spring stent. In some embodiments, the heat transfer increases the temperature of the shape memory material, causing the spring structure of the stent to undergo a shape memory transition from the constrained state toward the expanded state. Additionally or alternatively, in some embodiments, transitioning the dual leaf spring stent from the constrained state to the expanded state includes retracting a sheath covering the stent. For example, the technician or surgeon performing process 2400 may activate a tensioning mechanism or the like that retracts the sheath from the stent, thereby allowing the stent to expand from its collapsed state.

[0076] In various embodiments, the transition of the dual leaf spring stent from the collapsed state to the expanded state significantly increases the bore diameter of the aspiration device. The increased bore diameter may be configured to accommodate thrombus, plaque, and / or foreign material at the target site. In some embodiments, expansion of the dual leaf spring stent increases the bore diameter of the aspiration device to approximately the diameter of the tubular tissue within which the aspiration device is deployed.

[0077] In some embodiments, in block 2412, process 2400 includes aspirating material from the target site via a suction device. For example, a pump system or the like may be activated to generate negative pressure within the aspiration catheter of the aspiration device. Applying negative pressure to the aspiration catheter may generate a vacuum force at the lumen of the aspiration device. The vacuum force may draw thrombus, plaque, and / or foreign material, etc., through the expanded dual leaf spring stent into the lumen of the aspiration device and further into the aspiration device, thereby removing the material(s) from the subject. As described herein, the dual leaf spring stent, in its expanded state, may exhibit sufficient radial force to enable the stent to withstand the negative pressure of the aspiration catheter.

[0078] In some embodiments, in block 2415, process 2400 includes transitioning each dual leaf spring stent of the suction device from an expanded state to a constrained state. In some embodiments, transitioning the dual leaf spring stent from the expanded state to the constrained state includes retracting the stent into a sheath so that the sheath covers the stent and compresses it into a collapsed state. Alternatively, or in addition, in some embodiments, a sheath is advanced over the stent so that the sheath covers the stent and compresses it into a collapsed state.

[0079] In some embodiments, the process 2400 includes removing the suction device from the tubular tissue and the subject over the guidewire at block 2418. In some embodiments, removal of the guidewire can follow or occur simultaneously with removal of the suction device.

[0080] Conclusion Although some embodiments described herein relate to self-expanding stents for suction-based thrombectomy, those skilled in the art will understand that the teachings herein may also be applied to a wide range of medical procedures and devices. The embodiments described herein may be expandable to suit at least the applications described above. Various components of the embodiments described herein may be added, removed, rearranged, modified, duplicated, etc., as those skilled in the art find advantageous and / or necessary to implement a particular application in conjunction with the teachings of the present disclosure. In some embodiments, specific features, characteristics, materials, components, and / or devices may be applied as those skilled in the art find advantageous and / or necessary to implement a particular application in conjunction with the teachings of the present disclosure.

[0081] Moreover, numerous modifications and other embodiments of the present disclosure set forth herein will come to mind to those skilled in the art having the benefit of the teachings herein and presented in the foregoing description and the associated drawings. It is therefore to be understood that the present disclosure is not limited to the particular embodiments disclosed, and that modifications and other embodiments are intended to be included within the scope of any appended claims. Furthermore, while the foregoing description and associated drawings describe exemplary embodiments in the context of particular example combinations of elements and / or functions, it should be understood that alternative embodiments may provide various combinations of elements and / or functions without departing from the scope of any appended claims. In this regard, for example, different combinations of elements and / or functions than those expressly described above are also contemplated as being part of any appended claim. Although specific terms are employed herein, these terms are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A stent comprising a spring structure, the spring structure comprising: Applying a folding radial force in the folded state; Applying an expansion radial force in the expanded state; configured to apply a peak radial force during transition between the collapsed state and the expanded state; the folding radial force exceeds the expanding radial force; A stent wherein the peak radial force exceeds the collapse radial force and exceeds the expansion radial force.

2. The stent of claim 1 , wherein the spring structure comprises a plurality of double leaf springs.

3. Each of the double leaf springs comprises: a first curved arm; a second curved arm; a connection between a first end of the first curved arm and a first end of the second curved arm; a first vertical arm connected to a second end of the first curved arm; a second vertical arm connected to a second end of the second curved arm; a longitudinal member connected to opposing ends of the first vertical arm and the second vertical arm; The stent of claim 2 comprising:

4. The stent of claim 3 , wherein on a first side, each of the double leaf springs is connected to an adjacent double leaf spring via the longitudinal member.

5. 5. The stent of claim 4, wherein the longitudinal members of each double leaf spring are connected at the opposing ends to first and second vertical arms of an adjacent double leaf spring.

6. 6. The stent of claim 4 or claim 5, wherein on a second side opposite the first side, each double leaf spring is connected to an adjacent second double leaf spring via the connection between the first end of the first curved arm and the first end of the second curved arm.

7. 6. The stent of claim 3, wherein the first curved arm, the second curved arm, the first vertical arm, the second vertical arm, and the longitudinal member are integrally formed.

8. 6. The stent of claim 3, wherein in the expanded state, the first and second perpendicular arms are perpendicular to the longitudinal members.

9. The stent of claim 2 , wherein the plurality of double leaf springs are integrally formed.

10. The stent of claim 2 , wherein the spring structure comprises nitinol.

11. A stent comprising multiple rows of double leaf springs in an annular configuration, Each row of double leaf springs consists of: an upper section of the double leaf spring group; The lower section of the double leaf spring group Equipped with each double leaf spring in the upper section is connected to a corresponding double leaf spring in the lower section; the dual leaf spring of each section is connected to a first side of a longitudinal member defining a length of each row; A stent, wherein the longitudinal member is connected to each double leaf spring in the upper section or the lower section of each double leaf spring in another row.

12. Each of the double leaf springs comprises: a first curved arm; a second curved arm; a connection between a first end of the first curved arm and a first end of the second curved arm, wherein the second end of the first curved arm and the second end of the second curved arm define a span of the double leaf spring; a first vertical arm connected to the second end of the first curved arm; a second vertical arm connected to the second end of the second curved arm; Each of the longitudinal members; Equipped with 12. The stent of claim 11, wherein the first vertical arm and the second vertical arm are connected to the longitudinal member at opposite ends of the span.

13. the annular configuration is configured to transition the stent between a collapsed state and an expanded state; In the folded state, an angle between each of the vertical arms and the longitudinal member is an obtuse angle; The stent of claim 12, wherein in the expanded state, the angle between each of the perpendicular arms and the longitudinal member is a right angle.

14. 14. A kit comprising at least one stent according to claim 13, said kit comprising: The kit further comprises a respective sheath configured to cover at least one of the stents to maintain the collapsed state.

15. the at least one stent comprises at least one first stent and a second stent; the first stent has a first diameter in the expanded state; the second stent has a second diameter in the expanded state; The kit of claim 14 , wherein the second diameter is greater than the first diameter.

16. each double leaf spring of the first stent has a first thickness; each double leaf spring of the second stent has a second thickness; 16. The kit of claim 15, wherein the second thickness is less than the first thickness.

17. 17. The kit of any one of claims 14 to 16, further comprising at least one suction device comprising a respective sheath and at least one stent.

18. 20. A method of aspirating tubular tissue within a subject using the kit of claim 17, the method comprising: directing a guidewire through the object and into the tubular structure; deploying each of the sheaths and at least one of the stents into a target site in the tubular tissue via the guidewire, the at least one stent being housed within the sheath in the collapsed state; retracting the sheath and transitioning at least one of the stents from the collapsed state to the expanded state, the transition of the at least one stent to the expanded state expanding an inner lumen of the at least one suction device; Aspirating material from the target site via application of negative pressure to the dilated lumen. and

19. retracting at least one of the stents into the sheath to transition the at least one of the stents to the collapsed state, wherein the transition of the at least one of the stents to the collapsed state comprises: shrinking or shifting the inner lumen of the suction device; removing the aspiration device, the sheath, and the at least one stent from the subject over the guidewire; 20. The method of claim 18, further comprising:

20. 1. A stent comprising: a plurality of annular segments, each annular segment comprising a plurality of dual leaf springs in an annular configuration; Each double leaf spring in the first annular section comprises: a first curved arm; a second curved arm; a connection between a first end of the first curved arm and a first end of the second curved arm, wherein the second end of the first curved arm and the second end of the second curved arm define a span of the double leaf spring; a first vertical arm connected to the second end of the first curved arm; a second vertical arm connected to the second end of the second curved arm; Each of the longitudinal members; Equipped with the first vertical arm and the second vertical arm are connected to the longitudinal member at opposite ends of the span; the longitudinal member of each of the double leaf springs in the first annular section extends along a remaining subset of the plurality of annular sections, such that a corresponding double leaf spring in the remaining subset is partially composed of the longitudinal member.

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