Hybrid stent and stent retriever

Abstract

A stent that includes a hybrid network cluster of open and closed cells, the hybrid network cluster being arranged such that the closed cells are connected in a re-sheathing configuration. The open cells are not connected, and the stent can be delivered without a sheath to enhance flexibility. In one embodiment, the rings of the proximal closed cells are tapered, and the stent can be retrieved by engagement of a pusher assembly.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 139,684, entitled "Hybrid Stent", filed on January 20, 2021, and U.S. Provisional Application No. 63 / 273,409, entitled "Hybrid Stent and Stent Retriever", filed on October 29, 2021. U.S. Provisional Application No. 63 / 139,684 and U.S. Provisional Application No. 63 / 273,409 are hereby incorporated by reference in their entirety. Technical field

[0003] The present invention generally relates to the field of endovascular treatment of blood vessels, and more particularly to stent devices and systems. In some embodiments, these stent devices and systems relate to hemodynamically significant intracranial atherosclerotic disease (ICAD) and acute ischemic stroke (AIS). Background art

[0004] Medical devices that can benefit from the present invention include those characterized by a hollow interior that are introduced into a lumen and expand upon deployment. These devices move or are moved between a contracted state and an expanded state or configuration to facilitate deployment through a catheter and a guidewire. Such devices are typically introduced into a diseased location within a body blood vessel (e.g., a stenotic segment or an aneurysm) and can perform various functions, including support and / or occlusion.

[0005] Intraluminal stents typically have a relatively open structure with multiple interconnected struts that define pores or openings in and / or through the surface, which can allow endothelialization and more permanent fixation of the stent within the blood vessel after implantation. Certain stents have a particularly open structure to allow blood to flow through the openings and out to the peripheral arteries after implanting the stent near an aneurysm. Typically, pores or openings are added by masking and / or etching techniques or laser or waterjet cutting. Known stents include the Cordis Corporation TM series of self - expanding stents, which are described in numerous patents and published patent applications, including U.S. Patent Nos. 6,612,012; 6,673,106; 6,818,013; 6,833,003; 6,955,685; 6,960,227; 7,001,422; and 7,037,331 and U.S. Patent Application Publication No. 2005 / 0234536, all of which are incorporated herein by reference.

[0006] One potential drawback of known stents is that they may incorporate relatively complex struts or unit structures, which may be disadvantageous to the operational convenience of the design, such as when the diameter of the stent changes. For example, from a manufacturing perspective, a stent design may have unit shapes and characteristics that are well-suited to achieving desired effects or operational characteristics when manufactured at a given nominal size or diameter, but these shapes or characteristics may have to be changed or adjusted to maintain the same operational characteristics of stents manufactured at different nominal sizes or diameters. Additionally, when forming struts and / or units using laser or waterjet cutting processes, complex patterns may require long cutting times.

[0007] Accordingly, there is a need for a method to provide stents with improved unit structures, particularly stents that incorporate relatively simple unit structures and are adaptable to manufacturing stents of different nominal sizes without having to re-design the units during manufacturing. There is still a need for a stent unit solution that facilitates achieving the desired hemodynamics in body blood vessels, as well as the chronic outward force and radial resistance of stents of various nominal sizes through variations of units of the same shape.

[0008] There is a need for a method to provide stents with improved unit structures, thereby providing resheathing of the stents. In partial response to this problem, Tenne (US8,062,347B2) discloses a resheathable stent; however, it is relatively rigid. As will be disclosed hereinafter, the present invention provides an enhanced flexible resheathable stent.

[0009] In addition, due to acute ischemic stroke, there is a need for a method to provide a temporary stent, also known as a "stentretriever / stentriever", to provide immediate blood flow restoration to blood vessels blocked by clots and, after re-establishing blood flow, to address the clot itself. To address this problem, Ferrera et al. (US8,574,262B2) provide a potential solution for immediate blood flow restoration. The present invention can advantageously facilitate the natural dissolution of clots and also reduce or eliminate concerns about distal embolism caused by clot fragmentation. Several embodiments of the present invention are disclosed, which provide progressive or modular treatment based on the nature of the clot. The stent described in Ferrera et al. is a closed unit design and does not conform well to the shape of the blood vessel.

[0010] In addition, UIm, III, et al. (US10,888,346B2) provided a device platform for removing obstacles and other objects in animal blood vessels or other lumens. The system can be deployed in the lumen from one or more catheters and can include a strain gauge for measuring the tension on a wire. A variety of different basket designs are disclosed in this invention. A method of manufacturing such a basket from a single tube of memory metal without any welding, as well as a method of use, are also disclosed. Due to the limited number of connecting chains, the design structure described in this patent cannot provide sufficient pushability for the target lesion. Summary of the Invention

[0011] In one aspect, the present invention embodies as a stent, comprising a hybrid network cluster composed of open cells and closed cells, the hybrid network cluster being arranged such that the closed cells are connected in a re-sleevable configuration. The open cells are not connected and the stent can be without a sheath to enhance flexibility.

[0012] In a preferred embodiment, the hybrid network cluster composed of open cells and closed cells includes a plurality of rings formed by closed cells. Each ring formed by closed cells includes:

[0013] a) Multiple pairs of closed cells;

[0014] b) A plurality of straight connecting elements, each straight connecting element connecting a pair of closed cells to an adjacent circumferentially spaced pair of closed cells; and,

[0015] c) A plurality of flexible connecting elements, each flexible connecting element connecting longitudinally adjacent rings, wherein each pair of closed cells includes a proximal peak at the proximal end and a distal peak at the distal end, and the proximal peak of the ring is connected to the valley of an adjacent spaced ring by a flexible connecting element.

[0016] The distal peaks are unconstrained to enhance flexibility, while the proximal peaks are constrained to achieve re-sleevability.

[0017] In another aspect, the present invention embodies as a stent delivery system, comprising:

[0018] a) A catheter;

[0019] b) A shaft, which includes a distal end disposed within the catheter; and

[0020] c) A stent, comprising a hybrid network cluster composed of open cells and closed cells, the hybrid network cluster being arranged such that the closed cells are connected in a re-sleevable configuration. The open cells are not connected, and the stent can be without a sheath to enhance flexibility.

[0021] On the other hand, the present invention embodies a method for deploying a resheathing stent for stent-assisted coiling of hemorrhagic aneurysms and for the treatment of intracranial atherosclerotic diseases. The method includes inserting a catheter into a patient's vasculature, wherein the resheathing stent system is provided together with the catheter. The resheathing expandable stent includes a hybrid network cluster composed of open cells and closed cells, the hybrid network cluster being arranged such that the closed cells are connected in a resheathing configuration; and, the open cells are not connected, and the stent can be without a sheath to enhance flexibility. Longitudinal movement of the shaft relative to the resheathing expandable stent expands and contracts the resheathing stent.

[0022] In another aspect, the present invention embodies a method for deploying a resheathing but temporary stent for stent-assisted coiling of hemorrhagic aneurysms and for the treatment of intracranial atherosclerotic diseases.

[0023] In another broad aspect of the retrievable stent, the hybrid network cluster of open cells and closed cells includes a plurality of rings formed by closed cells, each ring formed by closed cells including: a) a plurality of closed cells; b) a plurality of distally directed connecting elements, each distally directed connecting element connecting a closed cell among the plurality of closed cells to an adjacent circumferentially spaced-apart closed cell through an associated distally directed connecting element of the adjacent circumferentially spaced-apart closed cell; c) a plurality of proximally directed connecting elements, each proximally directed connecting element connecting longitudinally adjacent rings, wherein each closed cell includes a distal peak and a proximal peak, the proximal peak of the closed cell being connected to the valley of an adjacent spaced-apart ring through a proximally directed connecting element; the first proximal ring is conical; and, d) a pusher wire assembly locatable within a guide of a stent delivery system, the pusher wire having a pusher wire proximal end and a pusher wire distal end, the pusher wire distal end being attached to the proximal peak of the closed cell of the first proximal ring.

[0024] In another broad aspect of the retrievable stent, each ring includes:

[0025] a) a plurality of closed cells, each closed cell including: i) a substantially diamond-shaped structure including: 1. a first unit strut; 2. a second unit strut opposite the first unit strut; 3. a third unit strut that connects the first unit strut to the second unit strut at a distal peak at an end of the ring; and, 4. a fourth unit strut that connects the second unit strut to the first unit strut; and

[0026] b) A plurality of distally-directed first connecting elements, each distally-directed first connecting element connecting the distal vertex of an open cell to an adjacent closed cell, the plurality of distally-directed first connecting elements including a set of distally-directed connecting elements associated with each said closed cell, wherein each set of distally-directed connecting elements includes: i. A distally-directed first connecting element extending from said distal vertex of the open cell, said distal vertex of the open cell being at the connection point of a distally-directed second connecting element and the adjacent closed cell; ii. A distally-directed second connecting element extending from said distal vertex of the open cell, said distal vertex of the open cell being at the connection point of the distally-directed first connecting element and the adjacent closed cell; and wherein said distally-directed first connecting element serves as the distally-directed second connecting element of adjacent circumferentially-spaced closed cells connected to the distal vertex;

[0027] c) A plurality of proximally-directed connecting elements, each proximally-directed connecting element connecting longitudinally adjacent rings, the plurality of proximally-directed connecting elements including a set of proximally-directed connecting elements associated with each said closed cell and the valley of an adjacent ring, wherein each set of proximally-directed connecting elements includes:

[0028] i. A proximally-directed first connecting element extending from the proximal peak of said closed cell; and,

[0029] ii. A proximally-directed second connecting element extending from said valley; wherein the distal peaks are unconstrained to enhance flexibility, and wherein the proximal peaks are constrained to achieve resheathing; and

[0030] d) A wire-pushing / pusher assembly locatable within a guide of a stent delivery system, the pusher assembly having a wire-pushing proximal end and a wire-pushing distal end, the wire-pushing distal end being attached to the proximal peak of a closed cell of the first proximal ring.

[0031] In another broad aspect, the invention is embodied as a retrievable stent including a hybrid network cluster of open cells and closed cells, the hybrid network cluster being arranged such that said closed cells are connected in a resheathing configuration; and, wherein the open cells are unconnected and the stent is capable of being sheathless to enhance flexibility; and, wherein the rings of the proximal closed cells are tapered and the stent is retrievable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a perspective view of a first embodiment of the stent of the invention.

[0033] Figure 2 is Figure 1 a side view of an embodiment of

[0034] Figure 3 is Figure 1The flattened pattern of an embodiment.

[0035] Figure 4 is Figure 1 The flattened pattern of an embodiment, where the rings are isolated and the remainder of the stent is shown in dashed lines.

[0036] Figure 5 An enlarged detail view of a pair of closed cells and their associated straight and flexible connecting elements.

[0037] Figure 6 is Figure 5 A perspective view of the enlarged detail.

[0038] Figure 7 A perspective view of a second embodiment of the stent of the present invention.

[0039] Figure 8 is Figure 7 The flattened pattern of an embodiment.

[0040] Figure 9 Shows the stent in an expanded configuration relative to the stent delivery system.

[0041] Figure 10 Displays a resheathable stent.

[0042] Figure 11 A perspective view of a third embodiment of the stent of the present invention.

[0043] Figure 12 is Figure 11 A side view of an embodiment.

[0044] Figure 13 is Figure 11 The flattened pattern of an embodiment.

[0045] Figure 14 is Figure 11 The flattened pattern of an embodiment, where the rings are isolated and the remainder of the stent is shown in dashed lines.

[0046] Figure 15 An enlarged detail view of a closed cell and its associated connecting elements.

[0047] Figure 16 is Figure 15 A perspective view of the enlarged detail.

[0048] Figure 17 A perspective view of a fourth embodiment of the stent of the present invention.

[0049] Figure 18 is Figure 17 A side view of an embodiment.

[0050] Figure 19Yes Figure 17 The flattened pattern of the embodiment of

[0051] Figure 20 Yes Figure 17 The flattened pattern of the example of , where the rings are isolated and the remainder of the stent is shown in dashed lines.

[0052] Figure 21 Is an enlarged detail view of the enclosed unit and its associated connecting elements.

[0053] Figure 22 Yes Figure 17 Perspective view of the enlarged detail of

[0054] In all the figures, the same elements or components are denoted by the same reference numerals, while equivalent elements have primes. Detailed Description of the Invention

[0055] Now referring to the drawings and the reference numerals marked thereon, Figure 1-5 There is shown a first embodiment of a stent implantable within a blood vessel of a subject's body, generally designated 10. The stent 10 has a proximal end 12 and a distal end 14 oriented with respect to the manner in which it is introduced. It includes a hybrid network cluster 16 of open cells 18, a distal enclosed unit 20, and a proximal enclosed unit 22. As will be disclosed below, the enclosed units 20, 22 are connected in a re-socketable configuration. The open cells 18 are not connected and the stent can be without a sheath to enhance flexibility.

[0056] From Figure 4 It can be best seen that the hybrid network cluster of open and enclosed cells includes a plurality of rings 24, 24', 24'' of multiple pairs of enclosed cells 20, 22. Each pair is generally designated 26 and includes a distal enclosed unit 20 and a proximal enclosed unit 22.

[0057] Each distal enclosed unit 20 has a generally rhomboidal shape. Each distal enclosed unit 20 includes a first distal unit strut 28, a second distal unit strut 30 opposite the first distal unit strut 28, a third distal unit strut 32 connecting the first distal unit strut 28 to the second distal unit strut 30 at a distal peak 34 of the ring 24, and a common strut 36 connecting the first distal unit strut 28 to the second distal unit strut 30.

[0058] The struts can have a strut wall thickness in the range of 0.05 - 0.15 mm, preferably about 0.076 mm. The strut widths are substantially the same.

[0059] From Figure 5-6As can best be seen, each proximal closure unit 22 has a substantially diamond shape. Each proximal closure unit 22 includes a first proximal unit strut 38, a second proximal unit strut 40 opposite the first proximal unit strut 38, a third proximal unit strut 42 connecting the first proximal unit strut 38 to the second proximal unit strut 40 at a proximal peak 44 at the proximal end of the ring 24, and a common strut 36 connecting the first proximal unit strut 38 to the second proximal unit strut 40.

[0060] Each ring 24 includes a plurality of straight connecting elements. Each straight connecting element connects a pair of closure units to an adjacent circumferentially spaced pair of closure units. A set of straight connecting elements is associated with each pair of said closure units. Referring to the pair of reference closure units 26, the set of straight connecting elements includes a first straight connecting element 48 extending from a first vertex 50. The first vertex 50 is the connection point of the first proximal unit strut 38 and the third proximal unit strut 42. A second straight connecting element 52 extends from a second vertex 54. The second vertex 54 is located at the connection point of the second distal unit strut 30 and the third distal unit strut 32.

[0061] The first straight connecting element 48 serves as a first vertex 50' to which a second straight connecting element 52' connects to an adjacent second vertex 54' of an adjacent circumferentially spaced pair of closure units 26'.

[0062] Each ring includes a plurality of flexible connecting elements. Each flexible connecting element connects longitudinally adjacent rings. A set of flexible connecting elements is associated with each pair of closure units. Referring to the pair of reference closure units 26, the set of flexible connecting elements includes a first flexible connecting element 56 extending from a first vertex 50. A second flexible connecting element 58 extends from the proximal peak 44.

[0063] The first flexible connecting element 56 serves as a second flexible connecting element 58' that connects to a first vertex 50' of an adjacent longitudinally spaced pair of closure units 26' of an adjacent ring 24'. The first vertex is at the valley of adjacent longitudinally spaced rings. In a preferred embodiment, each flexible connecting element includes a straight or "S" shaped configuration. There can be other suitable types of flexible connecting elements, for example, it can have a "V" shaped configuration.

[0064] Thus, the distal peaks are unconstrained to enhance flexibility, and the proximal peaks are constrained to achieve resheathing. This allows the stent to have the advantages of a closed cell system, such as the radial strength of an open plaque, etc. At the same time, it has the advantages of an open cell system, namely flexibility. Therefore, the present invention is very advantageous for ICAD applications.

[0065] Figure 1-4 The stent 10 shown has rings including 4 pairs of closure units. Thus, it is an octa-coronary device. In Figure 7-8In it, a second embodiment of the stent, generally designated 60, in which each loop has 3 pairs of closed cells. Thus, it is a 6-coronary device. In general, the stent may have 2 - 10 pairs of closed cells.

[0066] The hybrid network cluster of open and closed cells has a diameter preferably in the range of about 2 mm to 12 mm in the fully open position and a length preferably in the range of about 10 mm to 60 mm in the fully open position.

[0067] A preferred application of this embodiment of the stent (i.e., stent 10) is in neurovascular anatomy for the adjunctive coiling of acute ischemic aneurysms and the treatment of intracranial atherosclerotic diseases.

[0068] The stent is preferably formed from a shape memory alloy (SMA), such as nitinol. Alternatively, the stent may be formed from stainless steel, cobalt chromium, bioabsorbable plastics, or other suitable metals.

[0069] Reference Figure 2 , in some embodiments, the stent further includes a graft 23 formed of expanded polytetrafluoroethylene (ePTFE) material positioned on the outer surface of the hybrid network cluster of open and closed cells.

[0070] Figure 9 Shows the stent 60 ( Figure 7-8 of the type) positioned relative to a stent delivery device, generally labeled 62. The stent delivery device may include well-known components, including a guide sheath 64 (i.e., a catheter), a marker band 66, a core wire 68, a distal coil 70, and a proximal coil (hidden by the guide sheath).

[0071] The unit design can be manufactured by a variety of methods, such as laser cutting, etc.

[0072] In some embodiments, the expandable stent can be drug-eluting. The expandable stent can include a drug coating or covering selected from everolimus, paclitaxel, sirolimus, corolimus, and any other related compounds, salts, moieties, which potentially reduce the risk of thrombosis, lumen loss, and related challenges. In some embodiments, the expandable stent may include radiopaque markers, such as platinum, gold, silver, or tantalum. In some embodiments, the expandable stent may be made of a bioabsorbable material, such as a magnesium-based material, poly(lactic acid)-based (PLA's) polymers, etc.

[0073] Now reference Figure 11-16, showing a third embodiment of a stent in accordance with the principles of the present invention, generally designated 100, in which a removable and temporary stent is provided. As in the previous embodiments, the stent 100 has a proximal end 112 and a distal end 114 that are oriented with respect to the manner in which it is introduced. It includes a hybrid network cluster 116 of open cells 118 and closed cells 120. The open cells 118 are unconnected, and the stent can be without a sheath to enhance flexibility. Additionally, as described below, in addition to the performance of the first two embodiments, in this third embodiment, the closed cells 120 are connected in a removable configuration. This performance is achieved by the pusher assembly 122.

[0074] As Figure 14 shown, the hybrid network cluster of open and closed cells includes a plurality of loops 124, 124', 124"...... 124 formed by the closed cells 120 n . Each closed cell 120 has a substantially diamond-shaped structure. Each closed cell 120 includes: a first unit strut 128; a second unit strut 130 opposite the first unit strut 128; a third unit strut 132 that connects the first unit strut 128 at the distal peak 134 at the end of the respective loops 124, 124', 124"; and, a fourth unit strut 135 that connects the second unit strut 130 to the first unit strut 128.

[0075] Each loop 124, 124', 124"...... 124 n includes a first connection element 136 that points distally. Each of the first connection elements 136 that points distally connects the distal vertex 138 of the open cell 118 to an adjacent closed cell 120. The plurality of first connection elements 136 that point distally includes a set of connection elements that point distally associated with each of the closed cells 120 (i.e., 136, 136').

[0076] Reiterating, each set of distal connection elements 136, 136' includes a first connection element 136 that points distally extending from the distal vertex 138 of the open cell 118, and the distal vertex 138 is located at the connection point of the second connection element 136' that points distally and the adjacent closed cell 120.

[0077] The second connection element 136' that points distally extends from the distal vertex 138 of the open cell 118, and the distal vertex 138 of the open cell 118 is located at the connection point of the first connection element 136 that points distally and the adjacent closed cell 120.

[0078] Thus, as can be best seen in Figure 15 , the first connection element 136 that points distally serves as the second connection element 136' that points distally, connecting to the distal vertex 138 of the adjacent circumferentially spaced closed cell 120.

[0079] Each of the rings 124, 124', 124'', …… 124 n includes a plurality of proximally directed connection elements 140, 140', each proximally directed connection element 140, 140' connecting longitudinally adjacent rings 124. The plurality of proximally directed connection elements includes a set of proximally directed connection elements 140, 140' associated with each closed unit 120 and the valley 142 of the adjacent ring 124. Each set of proximally directed connection elements includes a first proximally directed connection element 140 extending from the proximal peak 148 of the closed unit; and a second proximally directed connection element 140' extending from the valley 142.

[0080] Thus, the first proximally directed connection element 140 serves as the second proximally directed connection element for the valley 142 of the adjacent ring, where the valley is located at the apex of the open unit of the adjacent longitudinally spaced rings.

[0081] The wire pusher assembly 144 can be positioned within the guide sheath of the stent delivery system (as referred to above Figure 9 described). The wire pusher assembly has a wire pusher proximal end (not shown) and a wire pusher distal end 146. The wire pusher distal end 146 is attached to the proximal peak 148' of the closed unit 120 of the first proximal ring 124. The first proximal ring 124 tapers towards the wire pusher distal end 146. Preferably, it is welded to the wire pusher distal end 146. The wire pusher assembly 144 preferably includes a flexible laser cut Hypotube formed of stainless steel and having a core wire formed of alloy.

[0082] Now referring to Figure 17-22 , a fourth embodiment of a stent in accordance with the principles of the present invention is shown, generally designated 200, in which a re-sheathing stent as in the first and second embodiments ( Figure 1-10 ) is provided. As in the previous embodiments, the stent 200 has a proximal end 212 and a distal end 214 oriented with respect to the manner in which it is introduced. It includes a hybrid network cluster 216 constructed of open units 218, distal closed units 220 and proximal closed units 222. As will be disclosed below, the closed units 220, 222 are connected in a re-sheathing configuration. The open units 218 are not connected and the stent can be provided without a sheath to enhance flexibility.

[0083] As best seen from Figure 20-22 , the hybrid network cluster of open and closed units includes a plurality of rings 124, 124', 124'' constituted by a plurality of pairs of closed units 220, 222. Each pair is generally designated 226 and includes a distal closed unit 220 and a proximal closed unit 222.

[0084] Each distal closure unit 220 has a substantially diamond shape. Each distal closure unit 220 includes a first distal unit strut 228, a second distal unit strut 230 opposite the first distal unit strut 228, a third distal unit strut 232 that connects the first distal unit strut 228 to the second distal unit strut 230 at a distal peak 234 at the distal end of the loop 224, and a common strut 236 that connects the first distal unit strut 228 to the second distal unit strut 230.

[0085] The struts can have a strut wall thickness in the range of 0.05 - 0.15 mm, preferably about 0.076 mm. The strut widths are substantially the same.

[0086] As Figure 21-22 Best seen in, each proximal closure unit 222 has a substantially diamond shape. Each proximal closure unit 222 includes a first proximal unit strut 238, a second proximal unit strut 240 opposite the first proximal unit strut 238, a third proximal unit strut 242 that connects the first proximal unit strut 238 to the second proximal unit strut 240 at a proximal peak 244 at the proximal end of the loop 224, and a common strut 236 that connects the first proximal unit strut 238 to the second proximal unit strut 240.

[0087] Each loop 224 includes a plurality of straight connecting elements. Each straight connecting element connects a pair of closure units to an adjacent circumferentially spaced pair of closure units. A set of straight connecting elements is associated with each pair of said closure units. Referring to the pair of closure units 226, the set of straight connecting elements includes a first straight connecting element 248 extending from a first vertex 250. The first vertex 250 is the connection point of the first proximal unit strut 238 and the third proximal unit strut 242. A second straight connecting element 252 extends from a second vertex 254. The second vertex 254 is located at the connection point of the second distal unit strut 230 and the third distal unit strut 232.

[0088] The first straight connecting element 248 serves as a second straight connecting element 252', connecting to a first vertex 250' of an adjacent second vertex 254' of an adjacent pair of circumferentially spaced closure units 226'.

[0089] Each loop includes a plurality of flexible connecting elements. Each flexible connecting element connects longitudinally adjacent loops. A set of flexible connecting elements is associated with each pair of closure units. Referring to the pair of closure units 226, the set of flexible connecting elements includes a third straight connecting element 256 extending from the first vertex 250. A fourth straight connecting element 258 extends from the proximal peak 244.

[0090] The first flexible connection element 256 serves as the second flexible connection element 258', connecting to the first vertex 250' of an adjacent pair 226' of longitudinally spaced closed units of an adjacent ring 224'. The first vertex is located at the trough of the adjacent longitudinally spaced rings. As described above, other embodiments and configurations can be designed without departing from the spirit of the present invention and the scope of the appended claims.

Claims

1. A stent, comprising: a proximal end and a distal end, a hybrid network cluster composed of open cells and closed cells; wherein the hybrid network cluster is arranged such that the closed cells are connected in a re-sheathing configuration; and wherein the open cells are not connected, and the stent can be without a sheath to enhance flexibility; wherein the hybrid network cluster composed of the open cells and the closed cells includes a plurality of rings formed by the closed cells, and each ring formed by the closed cells includes: a) multiple pairs of closed cells; b) a plurality of straight connecting elements, each straight connecting element connecting a pair of closed cells to an adjacent circumferentially spaced pair of closed cells; and c) a plurality of flexible connecting elements, each flexible connecting element connecting longitudinally adjacent rings, wherein each pair of closed cells includes a proximal peak at the proximal end and a distal peak at the distal end, and the proximal peak of the ring is connected to the valley of an adjacent spaced-apart ring by a flexible connecting element, wherein the distal peak is unconstrained to enhance flexibility, and wherein the proximal peak is constrained to achieve re-sheathing.

2. The stent according to claim 1, wherein, a) each pair of closed cells includes: i. a distal closed cell having a substantially diamond shape, including: 1). a first distal unit strut; 2). a second distal unit strut opposite to the first distal unit strut; 3). a third distal unit strut that connects the first distal unit strut to the second distal unit strut at the distal peak at the distal end of the ring; 4). a common strut that connects the first distal unit strut to the second distal unit strut; ii. a proximal closed cell having a substantially diamond shape, including: 1). a first proximal unit strut; 2). a second proximal unit strut opposite to the first proximal unit strut; 3). a third proximal unit strut that connects the first proximal unit strut to the second proximal unit strut at the proximal peak at the proximal end of the ring; 4). the common strut, shared between the distal closed cell and the proximal closed cell, the common strut connecting the first proximal unit strut to the second proximal unit strut; b) each group of straight connecting elements includes: i. a first straight connecting element extending from a first vertex, the first vertex being located at the connection point of the first proximal unit strut and the third proximal unit strut; ii. a second straight connecting element extending from a second vertex, the second vertex being located at the connection point of the second distal unit strut and the third distal unit strut, wherein the first straight connecting element serves as the second straight connecting element connecting to the second vertex of an adjacent circumferentially spaced pair of closed cells connected to the first vertex; c) each group of flexible connecting elements includes: i. a first flexible connecting element extending from the first vertex; and, ii. a second flexible connecting element extending from the proximal peak, wherein the first flexible connecting element serves as the second flexible connecting element connecting to the first vertex of an adjacent longitudinally spaced pair of closed cells of an adjacent ring, wherein the first vertex is located at the valley of adjacent longitudinally spaced rings, wherein the distal peaks are unconstrained to enhance flexibility, and wherein the proximal peaks are constrained to enable resheathing.

3. The stent according to claim 1, wherein the hybrid network cluster is formed of a shape memory alloy SMA.

4. The stent according to claim 3, wherein the SMA comprises nitinol.

5. The stent according to claim 2, wherein each of the plurality of rings comprises six pairs of closed units.

6. The stent according to claim 1, wherein each of the plurality of rings comprises three pairs of closed units.

7. The stent according to claim 2, wherein each of the plurality of rings comprises a number of pairs of closed units in the range between two pairs and ten pairs.

8. The stent according to claim 1, wherein each of the plurality of rings comprises six pairs of closed units.

9. The stent according to claim 1, wherein the hybrid network cluster formed by the open units and the closed units has a diameter in the range of 2 mm to 12 mm in the fully open position.

10. The stent according to claim 1, wherein the hybrid network cluster formed by the open units and the closed units has a length in the range of 10 mm to 60 mm in the fully open position.

11. The stent according to claim 1, wherein each flexible connection element comprises an "S" configuration.

12. The stent according to claim 1, wherein each flexible connection element comprises a "V" configuration.

13. The stent according to claim 1, further comprising a graft formed of expanded polytetrafluoroethylene ePTFE material, the graft being located on the outer surface of the hybrid network cluster formed by the open units and the closed units.

14. A stent comprising: a proximal end and a distal end, a hybrid network cluster formed of open units and closed units; wherein the hybrid network cluster is arranged such that the closed units are connected in a resheathable configuration; and wherein the open units are not connected and the stent is capable of being without a sheath to enhance flexibility; wherein the hybrid network cluster formed by the open units and the closed units comprises a plurality of rings formed of the closed units, each ring formed of the closed units comprising: a) a plurality of closed units; b) a plurality of distally directed connection elements, each distally directed connection element connecting one of the plurality of closed units to an adjacent circumferentially spaced apart closed unit through an associated distally directed connection element of the adjacent circumferentially spaced apart closed units; c) a plurality of proximally directed connection elements, each proximally directed connection element connecting longitudinally adjacent rings, wherein each closed unit comprises a distal peak and a proximal peak, the proximal peak of the closed unit being connected through a proximally directed connection element to the valley of an adjacent spaced apart ring; the first proximal ring is tapered; and, d) a pusher assembly capable of being located within a guide sheath of a stent delivery system, the pusher assembly having a pusher proximal end and a pusher distal end, the pusher distal end being attached to the proximal peak of a closed unit of the first proximal ring.

15. The stent according to claim 14, wherein the first proximal ring is welded to the pusher assembly.

16. A stent comprising: a proximal end and a distal end, a hybrid network cluster formed of open units and closed units; wherein the hybrid network clusters are arranged such that the closed units are connected in a re-socketable configuration; and wherein the open units are not connected and the stent is capable of enhanced flexibility without a sheath; wherein the hybrid network clusters formed by the open units and the closed units include a plurality of rings formed by the closed units, and each ring formed by the closed units includes: a) a plurality of closed units, each closed unit including: i. a structure substantially in a rhombus shape, including: 1). a first unit strut; 2). a second unit strut opposite to the first unit strut; 3). a third unit strut that connects the first unit strut to the second unit strut at a distal peak at an end of the ring; and 4). a fourth unit strut that connects the second unit strut to the first unit strut; and b) a plurality of distally-directed first connecting elements, each distally-directed first connecting element connecting a distal vertex of an open unit to an adjacent closed unit, the plurality of distally-directed first connecting elements including a set of distally-directed connecting elements associated with each of the closed units, and wherein each set of distally-directed connecting elements includes: i. a distally-directed first connecting element extending from the distal vertex of the open unit, the distal vertex of the open unit being located at a connection point between a distally-directed second connecting element and the adjacent closed unit; ii. a distally-directed second connecting element extending from the distal vertex of the open unit, the distal vertex of the open unit being located at a connection point between the distally-directed first connecting element and the adjacent closed unit; and wherein the distally-directed first connecting element serves as the distally-directed second connecting element of adjacent circumferentially-spaced closed units connected to the distal vertex; c) a plurality of proximally-directed connecting elements, each proximally-directed connecting element connecting longitudinally adjacent rings, the plurality of proximally-directed connecting elements including a set of proximally-directed connecting elements associated with each of the closed units and the valleys of adjacent rings, and wherein each set of proximally-directed connecting elements includes: i. a proximally-directed first connecting element extending from the proximal peak of the closed unit; and ii. a proximally-directed second connecting element extending from the valley; wherein the proximally-directed first connecting element serves as the proximally-directed second connecting element of adjacent rings connected to the valley, and wherein the valley is located at a vertex of an open unit of adjacent longitudinally-spaced rings, wherein the distal peak is unconstrained to enhance flexibility, and wherein the proximal peak is constrained to achieve re-socketability; and d) a pusher assembly capable of being located within a guide sheath of a stent delivery system, the pusher assembly having a pusher proximal end and a pusher distal end, and the pusher distal end being attached to the proximal peak of a closed unit of a first proximal ring.

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