Devices and methods for treating blocked blood vessels

Abstract

The present teachings provide devices and methods of delivering and deploying an expandable stent to treat intracranial atherosclerotic disease (ICAD) inside a blood vessels. The stent is delivered through a microcatheter with a pusher wire disposed within the microcatheter. During delivery, the pusher wire is coupled to the expandable stent. The stent has a flexible and conformable open-cell profile for conforming to ragged or calcified vessels, angulated vessels or tortuous anatomy. The stent is also configured to form a continuously longitudinal connection extending throughout its entire length for an efficient delivery through a microcatheter.

Description

DEVICES AND METHODS FOR TREATING BLOCKED BLOODVESSELSFIELD

[0001] The present teachings relate to a vascular endoprosthesis, such as a stent for treating blood vessels that has been weakened by damage or disease such as hemodynamically significant intracranial atherosclerotic disease (ICAD).BACKGROUND

[0001] Intracranial atherosclerotic disease (ICAD) occurs when the arteries inside the brain become clogged with plaque, which limits blood flow to the brain and increases the risk of a stroke. A stent is often used by the doctors to keep the artery propped open, allowing improved blood to flow to the brain. The stent provides a barrier to reduce the risk of recurrent narrowing of the artery and also supports the artery wall.

[0002] Depending on the density of the struts, stents can be classified as those with a closed-cell or an open-cell configuration. Closed-cell stents are characterized by small free cell areas between the struts, whereas open-cell stents have larger uncovered gaps.Flexibility and scaffolding are key characteristics derived from stent designs. Closed-cell stents are less flexible and may develop kinks and incomplete expansion. Conversely, stents with an open-cell configuration conform best to angulated vessels or tortuous anatomy. As such, open-cell stent is often a desirable choice for neurovascular application.

[0003] The present teaching discloses an open-cell stent configuration which is designed for the ease of a delivery through a microcatheter. Upon releasing from the microcatheter, the stent expands radially and permanently holds the artery open, which improves blood flow. The stent also holds the plaque against the artery wall. This reduces the risk of plaque breaking off, traveling to the brain, and causing a stroke.SUMMARY

[0004] One aspect of the present teachings provides an open-cell stent. In various embodiments, the open-cell stent comprises at least three crowns and at least two groups of connectors joining every two adjacent crowns. Each crown is a closed loop with a single strut extending in a zig-zag pattern forming a plurality of proximal apices and a plurality of distal apices. The proximal apices and the distal apices of the crowns longitudinally aligns with each other in a direction parallel to a longitudinal axis of the stent. Each connector has a distal end of joining a proximal apex of the crown distal to the connector, a proximal end joining a distal apex of the crown proximal to the connector. Each connector has a distal end portion, a middle triangle portion, and a proximal end portion. The middle triangle portion of each connectors has an open vertex with the distal end portion extending from a first side of the open vertex to the distal end of the connector, and the proximal end portion extending from a second side of the open vertex to the proximal end of the connector. The distal and proximal end portions longitudinally align with each other in a direction parallel to a longitudinal axis of the stent. The middle triangle portions of the connectors circumferentially offset from the distal and proximal end portions of the connector. The open-cell stent has a radially collapsed delivery configuration with at least two adjacent longitudinally continuous connections formed from the proximal end to distal end of the stent through the engagement of all crowns and connectors in a direction parallel to the longitudinal axis of the stent. The open-cell stent also has a radially expanded deployment configuration where each connectors in the same group offsets all connectors of the adjacent group circumferentially.

[0005] Another aspect of the present teachings provides that each group of connectors of the open-cell stent evenly distributes circumferentially among the apices of the crowns to be connected.

[0006] Another aspect of the present teachings provides that the middle triangle portion of each group of the connectors of the open-cell stent circumferentially offsets from the distal and proximal end portions of the connector in the same direction.

[0007] Another aspect of the present teachings provides that the middle triangle portion of a first group of the connectors of the open-cell stent circumferentially offsets from the distal and proximal end portions of the connector in the first direction. And the middle triangle portion of a second group of the connectors of the open-cell stent circumferentially offsets from the distal and proximal end portions of the connector in the second direction. The first direction and the second direction are opposite of each other.

[0008] Another aspect of the present teachings provides that when the open-cell stent has a radially collapsed delivery configuration, each of the open vertices of the middle portions of the connector closes with the proximal and distal end portions engage each other; a distal end of the middle portion of the connector engages an apex adjacent to the apex of the crown joining to the distal end of the connector; and a proximal end of the middle portion of the connector engages an apex adjacent to the apex of the crown joining to the proximal end of the connector.

[0009] Another aspect of the present teachings provides that each crown of the open-cell stent has the same number of apices.

[0010] Another aspect of the present teachings provides each group of connectors of the open-cell stent has the same number of connectors.

[0011] Another aspect of the present teachings provides that each of at least three crowns of the open-cell stent has 9 proximal apices and 9 distal apices. The proximal apices of at least three crowns align with each other longitudinally. The distal apices of at least three crowns align with each other longitudinally. In another aspect wherein each group of connectors of the open-cell stent has 3 connectors evenly distribute among the 9 apices of the two adjacent crowns.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Fig. 1 is a perspective view of an open-cell stent in its radially expanded profile in accordance with the present teachings.

[0013] Fig. 2 is a perspective view of an open-cell stent in its radially collapsed profile in accordance with the present teachings.

[0014] Fig. 3 is a perspective sectional view of crown of the open-cell stent in accordance with the present teachings.

[0015] Fig. 3A-3B are perspective sectional view of strut segment of the crown in accordance with the present teachings.

[0016] Fig. 4 is a perspective view of an exemplary open-cell stent in accordance with the present teachings.

[0017] Figs. 5A-5E are perspective views of various exemplary connectors for joining crowns of the open-cell stent in accordance with the present teachings.

[0018] Fig. 6 is a perspective views of an exemplary open-cell stent delivered via a delivery system in accordance with the present teachings.

[0019] Fig. 7 is a perspective views of an exemplary pusher wire in accordance with the present teachings.DETAILED DESCRIPTION

[0020] The present teachings are described more fully hereinafter with reference to the accompanying drawings, which show certain embodiments of the present teachings. The present teachings may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to illustrate various aspects of the present teachings. Like numbers refer to like elements throughout.

[0021] As used herein, the terms “radially outward” and “radially away” mean any direction not parallel with the central axis. For example, considering a cylinder, a radial outward member could be a piece of wire or a loop of wire attached or otherwise operativelycoupled to the cylinder that is oriented at an angle greater than 0° relative to the central longitudinal axis of the cylinder.

[0022] As used herein, the term “lumen” means a canal, duct, and generally tubular space or cavity in the body of a subject including veins, arteries, blood vessels, capillaries, intestines, and the like. The term “lumen” can also refer to a tubular space in a catheter, a microcatheter, or the like in a device.

[0023] As used herein the term “proximal” shall mean closest to the operator (less into the body) and “distal” shall mean furthest from the operator (further into the body). In positioning the medical device from a downstream access point, distal is more upstream and proximal is more downstream.

[0024] As explained in further detail below, various embodiments of the present teachings provide medical devices / systems to be implanted inside a narrowed or diseased intracranial blood vessel for providing scaffolding and for preventing future stenosis or occlusion. The medical devices / system can be used in anterior neurovascular circulation (including MCA, ICA) and posterior neurovascular circulation (including BA, VA). In some embodiments, the medical device, according to the present teachings, may be extended into an elongated profile for percutaneous delivery and resume to a radially expanded deployment profile upon release from the delivery system. As used in this application, unless otherwise indicated, the term “vessel” refers to a blood vessel, including an artery, an arteriole, a capillary, a venule, a vein, or a network of any of the combinations of the foregoing.

[0025] The present teaching relates to an open-cell stent intended for intracranial use. According to some embodiments, the stent is flexible and atraumatic and is available in various lengths and diameters, thin-walled, and / or radiopaque. In some embodiments, the stent is configured to be precisely delivered, retrieved, and repositioned. In some embodiments, the stent is flexible enough to be delivered via a microcatheter and to be placed in a small vessel but has sufficient radial forces to conform to the vessel wall geometry when deployed.

[0026] The stent has a radially expanded profile in which it rests against the inner wall of the blood vessel, and a radially reduced profile in which it fits inside a microcatheter for delivery. Fig. 1 illustrates an exemplary embodiment where such an open-cell stent (10) radially expands upon released from the delivery system. Fig. 2 illustrates an exemplary embodiment where such open-cell stent (10) radially collapses while constrained inside a delivery system. (Fig. 2 shows the radially collapsed stent unrolled / flattened, for the purpose of illustration.)

[0027] As shown in Figs.1-2, the open-cell stent (10), has a general tubular profile with an elongated lumen (16) extending from its distal end (12) to its proximal end (14). In this exemplary embodiment, the stent (10) has a plurality of crowns (20) joined together by plurality groups of connectors (30) strategically placed between every two crowns (20). The number of connector groups is one less than the number of crowns (20) making up a stent (10). The placement of the connectors (30) affords such a stent (10) a strong axial force transmission during device delivery and deployment, while also maintaining a maximum bending flexibility along the entire length of the stent (10). At the delivery profile, the stent (10) collapses radially with each crown (20) contracting radially inward toward the axial center (18) and all strut segments (26) forming the crown (20) packed tightly next to each other, such as shown in Fig. 2. In one embodiment, the radially collapsed stent (20) is sized to fit into 2-3 F catheter with ID 0.4-0.6mm ID. Upon deployment, each crown (20) expands radially away from the axial center (18) of each crown (20), all strut segments (26) forming the crown (20) moving away from each other assuming its pre-defined zig-zag profile and radial size. In one embodiment, the radially expanded stent 10) has a diameter of 2.5-5 mm. In one embodiment, upon deployment in vivo, the stent (10) anchors itself inside the blood vessel via radial outward force.

[0028] Continue referring to Fig. 1, wherein the stent (10) is made of a plurality of crowns (20) linked together with a plurality group of connectors (30). According to one embodiment of the present teaching, each crown (20) is in a profile of a continuous and closed loop with a single strut (26) extending from a first proximal apex (24) of the crown (20) distally reaching a first distal apex (22), then reversing its direction and extending fromthe first distal apex (22) proximally reaching a second proximal apex (24), and then reversing its direction and extending from the second proximal apex (24) distally reaching a second distal apex (22), etc. The same pattern continues until the crown (20) forms a close loop with a zig-zag pattern. According to one embodiment, each crown (20) has the same number of proximal apices (24) as the distal apices (22).

[0029] Fig. 1 further illustrates an exemplary embodiment of the connectors (30) linking the two adjacent crowns (20) together. Specifically, the connector (30) has a generally open triangle-shaped middle portion (36), with two straight-ended portions (32, 34) extending from the open vertex (38) of the triangle (36) to two ends of the connector (30). The distal end of the connector (30) joins a crown (20) distal to the connector (30), and the proximal end of the connector (30) joins a crown (20) proximal to the connector (30). As shown in Fig. 1, the open triangle-shaped middle portion (36) of the connector (30) offsets circumferentially from the two straight segments (32, 34). In the example embodiment as shown in Fig. 1, the middle triangle portions (36) of the connectors (30) of the same group are offset to the same direction.

[0030] Continue referencing Fig. 1, the exemplary embodiment of the stent (10) has a plurality of crowns (20), each with 9 apices (22, 24) and a plurality group of 3 connectors (30). Each apex (22, 24) of each crown (20) aligns with a respective apex (22, 24) of other crowns (20) forming a longitudinal form parallel to the longitudinal axis (18) of the stent (10). According to the exemplary embodiment, the 3 connectors (30) in the same group, evenly distribute circumferentially among the 9 apices (22, 24) of each crown (20). For example, as illustrated, 3 connectors (30) in the first group (counting from the proximal end of the stent) join apices 1, 4, and 7 of the first crown (20) (also counting from the proximal end of the stent) proximal to connector (30) with the apex 1, 4, and 7 of the second crown (10) distal to the connector (30), with the triangle middle portions (36) of all three connectors (30)in this first group offset circumferentially toward apices 2, 5, and 8 respectively.Continue referencing Fig. 1, the second group of connectors (30) joins the second crown (20) and the third crown (20). As illustrated, the second group connectors (30) join apices 2, 5, and 8 of the second crown (20) proximal to the connectors (30) with apices 2, 5, and 8 of thethird crown (20) distal to the connectors (30), with the triangle middle portions (36) of all three connectors (30) offset circumferentially toward apices 1, 4, and 7 respectively, i.e. opposite the offset direction of the first group of connectors (30). The third group of connectors (30), as illustrated in Fig.l, repeats the same placement profile of the first group of connectors (30), i.e. joining apices 1, 4, and 7 of the third crown (20) proximal to the connectors (30) with apices 1, 4, and 7 of the crown (20) distal to the connectors (30); and with their triangle middle portions (36) offset to the same direction as the first group of connectors (30). According to one embodiment of the present teaching, the pattern repeats with the fourth group of connectors (30) repeating the same placement profile of the second group of connectors (30); the fifth group of connectors (30) repeating the same placement profile of the third group of connectors (30), etc. According to one embodiment of the present teaching, the two end portions (32, 34) of each connector (30) are pre-defined to be slightly away from each and thereby keeping the vertex (38) open as shown in Fig. 1.

[0031] Now referencing Fig. 2, when the stent (10) is in its radially collapsed delivery profile, each crown (20) collapses radially with the strut segment (26) between proximal and apices (22, 24) pack tightly next to each other, all proximal apices (24) are closely proximate to each other, all distal apices (22) also closely proximate to each other. According to one embodiment of the present teaching, in the delivery profile, some strut segments (26) of each crown (20) along with the connectors together form continuous connections parallel to the longitudinal axis (18) of the stent (10) so that a distal pushing force is effectively transferred from the proximal end (14) of the stent (10) to the distal end (12) of the stent. Specifically, as illustrated, in this radially collapsed profile, the two vertices of the straight edge opposing the open vertex (38) of the middle triangle portion (36) of the connector (30) are configured to be in direct contact with the adjacent apices of the crowns (20). For example, for the first group of the connectors (30), the vertices (39) of the middle triangle portion contact the apices 2, 5, and 8 of first crown (20) proximal to the connector (30), and the vertices (37) of the middle triangle portion (36) contact the apices 2, 5, and 8 of second crown (20) distal to the connectors (30). In addition, the open vertices (38) of the middle triangle portions (36) of the connectors (30) also close allowing two end portions (32, 34) of the connectors (30) indirect contact with each other and thereby forming a continuous contact between the apices 1, 4, and 7 of the two adjacent crowns (20). As such, as illustrated in Fig. 2, the apices 1, 4, and 7, and apices 2, 5, and 8 of each crown (20) align axially and form a continuous longitudinal connection through the corresponding connectors (30) in between and thereby effectively transfer a proximal pushing force for the purpose of stent (10) delivery and deployment.

[0032] According to one embodiment of the present teaching, when the stent (10) is in its radially collapsed delivery profile, each connector (30) contracts longitudinally, with the free ends of the two end portions (32, 34) (i.e. the end of each end portion not connecting to the apex of the crown) contact each other and thereby close the open vertex (38) of the triangle, and the other two vertices (37, 39) of the triangle (36) contact adjacent apex of the crown (20) as described above. In another embodiment, when the stent (10) is in its radially expanded deployment profile, each connector (30) extends longitudinally, with the free ends of the two end portions (32, 34) (i.e. the end of each end portion not connecting to the apex of the crown) extending away from each other and thereby open the triangle vertex (38). As such, in one embodiment of the present teaching, the open triangle middle portion (36) of the connector is configured in such a way that the overall width of the connector (30), i.e. the distance from the open vertex (38) of the triangle (36) to the opposing edge of the triangle (36) is similar to the distance between two adjacent apices at the same end of the same crown (20) when the crown is in its radially collapsed delivery profile. The length of the triangle edge opposing the open vertex (38) is similar to the overall lengths of two end portions of the connector (30) when the stent (10) is in its radially collapsed delivery profile. Such connector (30) configuration ensures that the open-cell stent (10) forms a “spine”, i.e. a solid physical contact of the material through strut segments (26) of the crowns (20) and connectors during device delivery. In the exemplary embodiment shown in Figs. 1-2, 6 spines are formed when the stent (10) is placed in a microcatheter, and therefore offer strong axial force transmission necessary for device delivery.

[0033] According to one embodiment of the present teaching, as shown in Fig. 3A the single continues strut (26) forming a crown (20) has a width of 0.4-0.8mm and a thickness of0.6-0.9mm, as shown in Fig. 3. In some embodiment, at each turn, i.e. each proximal and / or distal apex (22, 24), the width of the strut (26) increases, as shown in Fig. 3B, in order to reduce stress concentration. In one embodiment, strut (26) forming the crown (20) has a width to thickness ratio of 1 : 1.2 to 1 :1.5, throughout the entire crown (20). In another embodiment, the width to thickness ration of the proximal and / or distal apex decreases as the width of the strut in this section increases. In one embodiment of the present teaching, in the radially collapsed delivery profile, each crown (20) has an overall length of 1.8-2.5mm, and a diameter of 0.4-0.6mm; and in the radially expanded deployment configure, each crown has an overall length of 1.75-2.35mm relative to its respective, and a pre-defined diameter of 2.2- 5mm. According to one embodiment, the crown’s overall length decrease while the overall diameter increase upon transforming from delivery profile to its pre-defined deployment profile.

[0034] According to one embodiment of the present teaching, the single continues strut forming the connector also has width of 0.4-0.8mm and a thickness of 0.6-0.9mm. In one embodiment, the strut forming the connector (30) has the same width to thickness ratio as the strut (26) forming the crown (20). In one embodiment, the strut forming the connector (30) has the same width as the strut (26) forming the crown (20). In another embodiment, the strut forming the connector (30) has the same thickness as the strut (26) forming the crown (20). According to one embodiment of the present teaching, from its distal end to its proximal end, the connector has an overall length of 0.3-0.5mm while the stent in its radially collapsed delivery profile; and an overall length slightly greater while the stent in its radially expanded deployment profile.

[0035] According to one embodiment of the present teaching, as shown in Fig. 1, the stent has 8 of crowns (20) linked together with 7 groups of connectors (30); each crown (20) has 9 apices and each group of connects (30) has 3 connectors (30) distributed evenly among the 9 apices. One skilled in the art should understand that the exact number of the crowns in a stent (10) could range from 4-10, thereby the specific number of the crowns in one stent as shown in this exemplary embodiment should not be viewed as limiting to the scope of the invention. Additionally, the number of apices of each crown could be 15-24 and the numberof connectors in one group could be 3-6, and thus the specific number of apices and the specific number of connectors in one group as shown in this exemplary embodiment should not be viewed as limiting to the scope of the invention.

[0036] In one embodiment, all crowns (20) have the exact same geometric construct, i.e., the same numbers of proximal apex (24), distal apex (22), and strut segments (26) in between, same strut width, same strut width to thickness ratio, same deployment length, etc. In another embodiment, while maintaining the same deployment diameter, the crowns (20) forming the stent (10) could vary in their geometry construct for achieving custom treatment purposes. For example, at least one crown could have different numbs of proximal apex, distal apex, and strut segments than the rest of the crowns. In another example, at least one crown could have a different deployed longitudinal length than the rest of the crowns. Yet in another example, at least one crown could have a different strut width to thickness ratio than the rest of the crowns.

[0037] In one embodiment of the present teaching, the stent (10) has a uniform diameter throughout its entire length. In another embodiment, the stent (100) has flared proximal (104) and distal ends (102), that is, the diameter of the stent (100) increases gradually from its middle portion toward its proximal and distal end portions, as shown in Fig. 4. In other words, the first crown (120) placed at the proximal end (104) of the stent (100) has the largest pre-defined deployment diameter; the second crown (120) distal to the first crown (120) has a smaller pre-defined deployment diameter comparing to the first crown (120); and the third crown (120) distal to the second crown (120) has an even smaller pre-defined deployment diameter comparing to the second crown (120). The distal end (102) of the stent (100) has a similar design as the proximal end (104) of the stent (100). That is the last crown (120) placed at the distal end of the stent (100) has the largest pre-defined deployment diameter; the second to last crown (120) proximal to the last crown (120) has a smaller predefined deployment diameter compared to the last crown (120); and the third to last crown (120) proximal to the second to last crown (120) has an even smaller pre-defined deployment diameter compared to the second to last crown (120). In some embodiments, the middle portion of the stent (100) has the smallest pre-defined deployment diameter compared to therest of the crown making up the same stent (10). Stent with such flared ends provides stronger radial outward force at its ends, and hence better vessel wall apposition. In one embodiment, stents (100) with flared ends are better suited for a proximal landing zone with a bigger vessel diameter

[0038] In one embodiment of the present teaching, there are less connectors in one group than the number of proximal apices and / or distal apices of the crown adjacent to the connector. In other words, not every apex of the two adjacent crowns is joined by a connector. In another embodiment, there are the same amount of connectors in one group as the number of proximal apices and / or distal apices of the crown adjacent to the connector. In other words, at least one of the crowns adjacent to the connectors has all their apices connected to a connector. In some embodiments, the connectors are evenly distributed circumferentially among the apices. In another embodiment, the connectors are unevenly distributed leaving bigger cells along one part of the circumferential surface, and smaller cells along the other part of the circumferential surface.

[0039] According to one embodiment of the present teaching, a group of connectors has at least two connectors circumferentially spaced from one and the other. In some embodiments, no connectors of two adjacent connector groups are aligned longitudinally for the purpose of increasing stent flexibility and reducing bending stiffness. In another embodiment, connectors of each group are strategically placed along the circumferentially surface of the stent, so that mass distribution of the stent is balanced, bending flexibility and the force required for delivery are optimized.

[0040] Figures 5A-5F show various embodiments of the connected design. Fig. 5A shows a bridge connector (40), where a straight strut joins two adjacent crowns at their respective apices. In one embodiment, the bridge connector joins two longitudinally aligned apices, as shown in Fig. 5A. This type of connector placement offers a strong force transmission during delivery. In another embodiment, the bridge connector (42) joins two offset apices as shown in Fig. 5B. This type of connector placement is adopted when greater vessel wall apposition, upon stent deployment, is desired.

[0041] Fig. 5C shows a “V” shaped connector (44), where each endpoint of the “V” connector (44) joins a respective apex, and the vertex of the “V” connector (44), offsets circumferentially from the two endpoints. In some embodiment, the V-shaped connectors (44) could have a symmetrical profile, for example, as shown in Fig. 5C, where the symmetrical profiled the V-shaped connector (44) joins two longitudinally aligned apices. In another embodiment, the V-shaped connectors (44) could have an asymmetrical profile, for example, as shown in Fig. 5D, where the asymmetrical profiled V-shaped connector (46) joins two offset apices. The V-shaped connector (46) offers better flexibility, and improved conformance to the surrounding vessel wall. Fig. 5E shows an “S” shaped connector (48) incorporated in between crowns. Similar to the V-shaped connector (44), each endpoint of the S-shaped connects (46) joins a respective apex. Two U-turn in between the two endpoints of the S-shaped offers greater flexibility than the V-shaped connectors. In another embodiment, the connector (49) could have a wavy shape such as shown in Fig. 5F.

[0042] In some embodiment, all connector groups have the same number of connectors. In another embodiment, at least one connector group has a different number of connectors than the rest. In one embodiment, the connectors in the same group have the same profile. In another embodiment, at least one group of the connectors has a different profile than the rest of the groups.

[0043] According to one embodiment of the present teachings, the stent expands upon deployment in vivo. In one embodiment of the present teachings, upon deployment, the stent expands radially due to the elastic nature of the material. In another embodiment, such radial expansion is achieved by the pre-set thermal shape memory of the strut material.

[0044] According to one embodiment of the present teaching, the stent is fabricated by laser-cutting or acid-etching a pattern into a preformed tube, then shape-setting the device to the intended radial expanded configuration. In such embodiments, the mesh is formed by slotting a hollow tube, for example, with a machining laser, or other methods, and expanding the slotted hollow tube to form an open structure. Alternatively, the device may also be formed with metallic strands that are pre-bent into the desired shape and then bondedtogether to connect elements either by welding or adhesive bonding. They can be welded by using a resistance welding technique or an arc welding technique, preferably in an inert gas environment and with cooling to control the grain structure in and around the weld site. These joints can be conditioned by using coining or upset forging to reduce the grain size and optimize the fatigue performance after the welding procedure. The term “strand” used herein can be wires, cords, fibers, yarns, filaments, cables, threads, or the like, and these terms may be used interchangeably.

[0045] In some embodiments, the device in whole or portion(s) is made of an elastic material, super-elastic material, or shape-memory alloy which allows said portions to distort into a generally straightened profile during the delivery process and resume and maintain its intended profile in vivo once it is deployed from the delivery catheter. In some embodiments, the device is made of stainless steel, nitinol, Titanium , Elgiloy, Vitalium, Mobilium, Ticonium, Platinore, Stellite, Tantalum, Platium, Hastelloy, CoCrNi alloys (e.g., trade name Phynox), MP35N, or CoCrMo alloys or other metallic alloys. Alternatively, in such embodiments, part or all of the device is made of any flexible, biocompatible material including, but not limited to polyester fabrics, Teflon-based materials, such as ePTFE, UHMPE, HDPE, polypropylene, polysulfone, polyurethanes, metallic materials, polyvinyl alcohol (PVA), extracellular matrix (ECM) isolated from mammalian tissue, or other bioengineered materials, bioabsorbable polymers such as polyactic acid, polyglycolic acid, poly caprolactone, or other natural materials (e.g., collagen), or combinations of these materials.

[0046] In one embodiment of the present teaching, the stent incorporates a plurality of visualization markers that allow a clinician to assess the delivery, deployment and / or emboli- capturing state of the device. These visualization markers are strategically placed along various portions of the stent which allows a clinician to easily identify the orientation of the device within under x-ray, and accurately assess the device engagement with the blood vessel at the treatment location. These radiopaque markers are used to visualize the device by using radiographic imaging equipment, such as X-ray or fluoroscopy, magnetic resonance, ultrasound, or other imaging techniques. A radiopaque marker can be sewn, adhered, swagedriveted, otherwise placed, and secured in or on the device. The radiopaque marker may be made of tantalum, tungsten, platinum, iridium, gold, or alloys of these materials or other materials that are known to those skilled in the art. The radiopaque marker can also be made of numerous paramagnetic materials, including one or more elements with atomic numbers 21-29, 42, 44, and 58-70, such as chromium (III), manganese (II), iron (III), iron (II), cobalt(II), copper (II), nickel (II), praesodymium (III), neodymium (III), samarium (III), ytterbium(III), gadolinium (III), terbium (III), dysprosium (III), holmium (III) and erbium (III), or other MR visible materials that are known to those skilled in the arts.

[0047] Fig. 6 depicts the use of an embodiment of the present teachings in conjunction with a delivery system, which can be manipulated externally by a clinician. In one embodiment, the stent (10) is delivered with a pusher wire (70) through a microcatheter (60). The microcatheter (60) has a distal, a proximal end, an axial lumen, and a pusher wire (70) slidably disposed within the lumen of the microcatheter (60). Both the microcatheter (60) and the pusher wire (70) can be manipulated by a clinician proximally. In this particular embodiment, the stent (10) extended into its radially collapsed delivery profile is slidably disposed over a distal portion of the pusher wire (70). The pusher wire (70) carrying the stent (10) is then placed inside the longitudinal lumen (16) of the stent structure (10).

[0048] Fig. 7 illustrates an exemplary embodiment of the pusher wire (70) and radially collapsed stent assembly. As further illustrated in Fig. 7, the pusher wire (70) has a distal bumper (72) and a proximal bumper (74). The proximal bumper (74) has a distal flat surface (75) configured for engaging the proximal end of the stent and to apply a distal pushing force to the stent during delivery and deployment, and the distal end of the stent engages the proximal ramp (73) of the distal bumper (72). During stent delivery, upon positioning a microcatheter (60) at the treatment location, the pusher wire (70) holding the radially collapsed stent is then pushed distally through the longitudinal lumen of the microcatheter (60) until reaching a distal end portion of the microcatheter (60). The stent is then deployed by holding the pusher wire (70) steady while retracting the microcatheter (60) proximally; or alternatively, by holding the microcatheter (60) steady while pushing the pusher wire (70)distally. Upon the freeing of the constraint by the microcatheter (60), the stent expands radially engaging the blood vessel.

[0049] The techniques disclosed for delivering and deploying the embodiments described herein are only examples. It should be understood that other techniques can be used instead of, or in combination with, these teachings. For example, the techniques used to deploy an embodiment of the devices described herein depend on the particular features of the device, the delivery system, and the anatomy in which the device is being deployed.

[0050] Various embodiments have been illustrated and described herein by way of examples, and one of ordinary skill in the art will appreciate that variations can be made without departing from the spirit and scope of the present teachings. The present teachings are capable of other embodiments or of being practiced or carried out in various other ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which these present teachings belong. Methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present teachings. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Claims

WE CLAIM:

1. An open-cell stent comprises: a general tubular structure has at least three crowns joined together by a plurality connectors; wherein each crown is formed by a continuous single strut extending in a zig-zag pattern forming a closed loop; wherein each crown has a plurality of proximal apices and a plurality of distal apices; and wherein the proximal apices and the distal apices of two adjacent crowns align longitudinally with each other in a direction parallel to a longitudinal axis of the stent; wherein each connector has a distal end portion, a middle triangle portion with an open vertex, and a proximal end portion; wherein the distal end portion of each connector extends from a first side of the open vertex to a distal end of the connector; the proximal end portion of the connector extends from a second side of the open vertex to a proximal end of the connector; wherein the distal and proximal end portions of each connector longitudinally align with each other in a direction parallel to a longitudinal axis of the stent; and the middle triangle portion of each connectors circumferentially offsets from the distal and proximal end portions of the connector; and wherein the distal end of each connector joins a proximal apex of the crown distal to the connector, the proximal end of each connector joins a distal apex of the crown proximal to the connector.

2. The open-cell stent of claim 1, wherein the stent has a radially collapsed delivery configuration where each open vertex of each connector closes with the proximal and distal end portions of the connector engaging each other; a distal end of each side of the middle triangle portion opposite to the open vertex of the connector engages a proximal apex of the crown joined to the distal end of the connector, and a proximal end of the side of the middle triangle portion opposite to the open vertex engages a distal apex of the crown joined to the proximal end of the connector.

3. The open-cell stent of claim 2, wherein all middle triangle portions of the plurality of connectors circumferentially offset from the distal and proximal end portions of the same connectors in the same direction.

4. The open-cell stent of claim 2, wherein the middle triangle portions of the connectors joining the same two adjacent crowns offset from the distal and proximal end portions of the same connectors in the same direction.

5. The open-cell stent of claim 2, wherein at least one middle triangle portion of the connector offsets from the distal and proximal end portions of the same connector in an opposite direction to another connector joining the same two adjacent crowns.

6. The open-cell stent of claim 2, wherein the middle triangle portions of a first plurality of connectors joining a first two adjacent crowns circumferentially offset from the distal and proximal end portions of the same connectors in a first direction; the middle triangle portions of a second plurality of connectors joining a second two adjacent crowns circumferentially offset from the distal and proximal end portions of the same connectors in a second direction; and wherein the first direction and the second direction are opposite to each other.

7. The open-cell stent of claim 6, wherein the sides of the middle triangle portions opposite to the open vertices of the first and second plurality of connectors align longitudinally with each other in a direction parallel to the longitudinal axis of the stent.

8. The open-cell stent of claim 1 , wherein a first plurality of connectors joining a first two adjacent crowns circumferentially offset from a second plurality of connectors joining a second two adjacent crowns.

9. The open-cell stent of claim 1, wherein the stent has a radially expanded deployed configuration where both ends of the sides of the middle triangle portions opposite to the open vertices disengage from the adjacent apices of the adjacent crowns.

10. The open-cell stent of claim 1, wherein the plurality of connectors distribute evenly and circumferentially between two adjacent crowns.

11. The open-cell stent of claim 1, wherein all crowns have a same number of apices.

12. The open-cell stent of claim 11, wherein each crown has nine proximal apices and nine distal apices.

13. The open-cell stent of claim 1, wherein a same number of connectors joins every two adjacent crowns.

14. An open-cell stent comprises: a general tubular structure has at least three crowns joined together by at least two groups of connectors; wherein a first group of connectors joining a first two adjacent crowns circumferentially offset from a second plurality of connectors joining a second two adjacent crowns; and wherein the stent has a radially collapsed delivery configuration with at least one continuous crown- connector connection extending from a distal end to a proximal end of the stent, wherein the crown- connector connection is formed by the crowns and the connectors engaging each other in a longitudinal direction parallel to a longitudinal axis of the stent.

15. The open-cell stent of claim 14, wherein each crown is formed by a continuous single strut extending in a zig-zag pattern forming a closed loop; wherein each crown has a plurality of proximal apices and a plurality of distal apices; and wherein the proximal apices and the distal apices of two adjacent crowns align longitudinally with each other in a direction parallel to a longitudinal axis of the stent.

16. The open-cell stent of claim 15, wherein each connector has a distal end portion, a middle triangle portion with an open vertex, and a proximal end portion; wherein the distal end portion of each connector extends from a first side of the open vertex to a distal end of the connector; the proximal end portion of the connector extends from a second side of the open vertex to a proximal end of the connector, and wherein the distal end of each connector joins a proximal apex of the crown distal to the connector, the proximal end of each connector joins a distal apex of the crown proximal to the connector.

17. The open-cell stent of claim 16, wherein the middle triangle portion of each connector circumferentially offsets from the distal and proximal end portions of the same connector.

18. The open-cell stent of claim 17, wherein in the radially collapsed delivery configuration, the at least one continuous crown-connector connection is formed by the middle triangle portions of the connectors engaging adjacent apices of the adjacent crowns.

19. The open-cell stent of claim 17, wherein in the radially collapsed delivery configuration, the first side and the second side of the same open vertex engage each other.

20. The open-cell stent of claim 14, wherein the stent has a radially expanded deployed configuration where the continuous crown-connector connection breaks up.

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