Devices and methods for treating blocked blood vessels

Abstract

To provide devices and methods of engaging, capturing, and retrieving emboli.SOLUTION: One aspect of the present teachings provides a device comprising: a substantially cylindrical stent body (12); and a distal net (120). The stent body (12) is configured to engage and capture emboli, while the distal net (120) is configured to restrict blood flow, and capture embolic debris. Certain embodiments of the present teachings also provide, devices and methods of engaging blood clots, while better assist aspiration. Other aspects of the present teachings provide methods of use thereof to percutaneously remove blood clots with minimum risks.SELECTED DRAWING: Figure 5B

Description

Technical Field

[0001] Cross - reference to Related Applications

[0002] The present teachings relate to methods for using minimally invasive catheters and minimally invasive catheter delivery embolus capture devices in the vasculature, and more particularly to minimally invasive catheter delivery embolus capture devices suitable for perfusing minimally invasive catheters in the brain and vasculature.

Background Art

[0003] Mechanical thrombectomy devices attempt to rescue an ischemic but not yet fully infarcted brain by first restoring perfusion through an occluded artery. Each class of mechanical thrombectomy device achieves recanalization by somewhat different biomechanical mechanisms.

[0004] Vessels There are three types of catheter - based thrombectomy devices commercially available: aspiration catheters that suck blood clots from vessels, thrombolytic agent delivery catheters that inject a targeted thrombolytic treatment into the blood clot, and mechanical thrombectomy systems that engage and pull in the blood clot. Commercially available systems may combine one or more of such characteristics. Such approaches each have advantages and disadvantages.

[0005] The aspiration catheter uses vacuum aspiration to remove blood clots caused by occlusion in acute ischemic stroke. Manual aspiration of the target thrombus can be performed through any microcatheter, such as by applying the suction action through a hole small enough to fit within the intracranial artery. The aspiration catheter is often used in rapid single - session recanalization to remove small, fresh, and soft thrombi. However, larger and more consolidated thrombi are intractable with this method and may occlude the small openings of the manual aspiration catheter. Additionally, manual aspiration may leave thrombi unremoved more likely than mechanical methods. As an added complication, the aspiration catheter generally has a large outer profile, making it difficult to cross lesions.

[0006] Catheter - directed thrombolysis (CDT) with a thrombolytic delivery catheter is the local delivery of a thrombolytic agent via a catheter to dissolve thrombi and reopen blood flow. Thrombolytic therapy provides improved outcomes compared to standard anticoagulant therapy, but thrombolytic therapy alone is often not fast enough to resolve major cardiac occlusions as seen in STEMI or in recanalization in the peripheral vasculature. In peripheral cases, thrombolytic - only treatment may lengthen the length of stay in the ICU and may require frequent angiographic reassessment for follow - up. To treat a large thrombus burden in the neurovascular system, a significant amount of thrombolytic agent is often administered systemically until the occlusion is completely dissipated. Delivery of such large amounts of thrombolytic agent can increase the risk of bleeding.

[0007] Mechanical thrombectomy combined with systemic thrombolysis is the current standard treatment for acute ischemic stroke. There are two types of mechanical thrombectomy systems: the coil retriever and the stent retriever. The coil retriever is composed of nitinol shape memory wire and is delivered through a microcatheter across the target clot. As the device is extruded from the delivery catheter, it immediately resumes its original coil shape. The neurointerventionist deploys the loops of the coil through the clot to engage the thrombus and then pulls both the coil and the clot into the catheter, similar to pulling the cork out of a wine bottle. The stent retriever is a self-expanding stent that expands within the occluded blood vessel with thrombus, engages the thrombus, and entraps the thrombus within the stent struts. The stent and thrombus are then withdrawn into the delivery catheter.

[0008] Due to its ability to achieve recanalization in a single session, the stent retriever can remove clots with a higher probability than manual aspiration methods and can achieve recanalization in a significantly shorter time than in the case of thrombolytic therapy alone. However, despite the superiority in enhancing clinical outcomes in patients with acute ischemic stroke, the stent retriever is not without complications. Recent studies have shown that such devices may cause vascular damage that spreads to the inner layer. Another common drawback of the stent retriever is that the retrieval of the stent inevitably induces fragmentation of the clot, which may lead to distal embolization and occlusion of previously unobstructed areas. Therefore, there is room for improvement.

Summary of the Invention

[0009] One aspect of the present disclosure provides an embolic capture device. In various embodiments, the embolic capture device comprises an elongate stent body having a plurality of cells along the elongate body. The elongate stent body has a longitudinal axis extending from a proximal end to a distal end. A plurality of proximal struts are coupled to the proximal end of the stent body to form a proximal hub. Each of the plurality of cells has a proximal end and a distal end, which together form a cell axis. At least one cell axis forms a constant angle with the longitudinal axis of the elongate stent body.

[0010] Another aspect of the present disclosure provides an embolic capture device. In various embodiments, the embolic capture device comprises an elongate stent body having a plurality of cells along the elongate body. The elongate stent body has a longitudinal axis extending from a proximal end to a distal end. The elongate stent body has a radially collapsed delivery profile and a radially expanded deployed profile. The elongate stent body is configured to rotate about its longitudinal axis as it transitions from the radially collapsed delivery profile to the radially expanded deployed profile.

[0011] One aspect of the present disclosure provides an embolic capture device. In various embodiments, the device has an elongate stent body with a proximal end where a plurality of proximal struts are coupled to form a proximal hub. In some embodiments, the device also has a distal mesh positioned distally of the stent body and having an adjustable distance to the distal end of the stent. Another aspect of the present disclosure provides a pusher shaft and a pull wire. The pusher shaft is coupled to the proximal end of the stent body. The pull wire extends through the proximal hub and the elongate stent body and is coupled to the distal mesh. In some embodiments, the stent body and the distal mesh move independently of each other such that the distance between the distal end of the stent and the distal mesh changes.

[0012] Another aspect of the present teachings provides an embolus capture device. In various embodiments, the device has an elongate stent body with a proximal end where a plurality of proximal struts are joined to form a proximal hub. In some embodiments, the device also has a distal mesh that is positioned distally of the stent body and has an adjustable distance to the distal end of the stent. Another aspect of the present teachings provides a device having a first configuration with a first distance between the distal mesh and the distal end of the stent body and a second configuration with a second distance between the distal mesh and the distal end of the stent body.

[0013] Another aspect of the present teachings provides an embolus capture device. In various embodiments, the device has an elongate stent body with a proximal end where a plurality of proximal struts are joined to form a proximal hub. In some embodiments, the device also has at least one mesh network positioned within the elongate stent body. The proximal edge of the mesh network is joined to the inner lumen wall of the stent. The distal tip of the mesh network is located near the longitudinal axis of the stent body. Another aspect of the present teachings provides a device having a first configuration in which the stent body and the internal mesh network are both radially constricted and a second configuration in which the stent body and the mesh network both radially expand.

[0014] Another aspect of the present teachings provides an embolus capture device. In various embodiments, the device has an elongate stent body with a proximal end where a plurality of proximal struts are joined to form a proximal hub. In some embodiments, the device also has at least two stabilizing struts. The proximal ends of the stabilizing struts are connected to the inner lumen surface of the stent body. The distal ends of the stabilizing struts are joined to form a hub. Another aspect of the present teachings provides a pusher shaft and a pull wire. The pusher shaft is connected to the proximal end of the stent body. The pull wire extends through the proximal hub and the elongate stent body and is connected to the hub of the stabilizing strut.

[0015] Another aspect of the present teachings provides an embolus capture device. In various embodiments, the device has an elongate stent body with a proximal end where a plurality of proximal struts are joined to form a proximal hub. In some embodiments, the device also has at least two directional struts. The proximal ends of the directional struts are joined to form a first hub. The distal ends of the directional struts are joined to form a second hub. The midpoint of each strut is defined on the inner lumen surface of the stent body. The midpoint is distal and radially outward from the proximal end. Another aspect of the present teachings provides a pusher shaft and a pull wire. The pusher shaft is joined to the proximal end of the stent body. The pull wire extends through the proximal hub of the stent body and through the elongate stent body and is joined to the first hub of the directional struts.

[0016] Another aspect of the present teachings provides an embolus capture device. In various embodiments, the device has a generally elongate body. The generally elongate body has at least one continuous portion and at least one discontinuous portion. In some embodiments, the continuous portion has an open cell surface structure. The discontinuous portion is configured to be larger than one open cell. Another aspect of the present teachings provides that the discontinuous portions are spaced linearly along the generally elongate body of the device.

[0017] Another aspect of the present teachings provides an embolus capture device. In various embodiments, the device has an elongate wire with a distal portion. In some embodiments, a ribbon is wrapped helically around the distal portion of the elongate wire. Another aspect of the present teachings provides that the device has a first configuration where the ribbon is tightly wrapped around the distal portion of the wire and a second configuration where the ribbon is unwound and radially expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0018]

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DETAILED DESCRIPTION OF THE INVENTION

[0019] In one aspect, the present disclosure is more fully described below with reference to the accompanying drawings, which show certain embodiments of the present disclosure. However, the present disclosure 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 to illustrate various aspects of the present disclosure. Like numbers refer to like elements throughout.

[0020] In one aspect, the present disclosure provides an embolus removal system by means of a catheter. In some embodiments, the system of the present disclosure is used to remove blood clots from a tube within the body. In some embodiments, the tube is a vein. In some embodiments, the system is used to treat deep vein thrombosis (DVT) in a vein and pulmonary embolism (PE) in an artery, ST-segment elevation myocardial infarction (STEMI), and ischemic stroke. In some embodiments, the system can also rapidly remove arteriovenous grafts for dialysis therapy that are prone to thrombosis. According to some embodiments, when the embolus removal system by means of a catheter of the present disclosure is deployed within a blood vessel, the embolus removal device expands and moves in a proximal direction along the blood vessel such that the embolus is substantially contained within the basket of the mesh of the embolus removal device. Specifically, the present disclosure provides a device / system and method for removing emboli in the neurocranium without causing distal complications associated with the removal of a larger portion of the retrieved embolus, distal to the location where the embolus initially occurred.

[0021] As used herein, "radially outward" and "radially away" mean any direction that is not parallel to the central axis. For example, considering a cylinder, a radially outward member can be a portion of a wire or a loop of wire that is attached to or otherwise operably coupled to the cylinder and is oriented at an angle greater than 0° with respect to the longitudinal axis of the center of the cylinder.

[0022] As used herein, the term "lumen" means a tube, conduit, generally tubular space or cavity within a subject's body, including veins, arteries, blood vessels, capillaries, the intestinal tract, and the like. The term "lumen" may also refer to a tubular space in a catheter, microcatheter, etc. within a device.

[0023] As used herein, the term "proximal" means closest to the operator (least intrusive within the body), and the term "distal" means farthest from the operator (most deeply intrusive within the body). When positioning a medical device from a downstream access point, the distal end is more upstream and the proximal end is more downstream.

[0024] As used herein, the term "embolus" may be a blood clot, thrombus, etc., and such terms may be used interchangeably.

[0025] As will be described in more detail below, various embodiments of the present teachings provide medical devices / systems for removing blood clots from blood vessels within the body. In some embodiments, the medical device / system may include an embolus capture device or means configured to capture a blood clot. In some embodiments, a pusher shaft is coupled to the embolus capture device. In some embodiments, the pusher shaft pushes and / or pulls the embolus capture device. In some embodiments, an embolus capture device according to the present teachings extends to an elongated outer shape for percutaneous delivery, assumes an expanded outer shape that expands radially to capture a blood clot, and extends back to an elongated outer shape to retrieve the blood clot. As used in this application, unless otherwise indicated, the term "vessel" refers to a blood vessel and includes any network of arteries, arterioles, capillaries, venules, veins, or combinations of the foregoing.

[0026] In another aspect, the present teachings disclose an embolic capture device for use within the skull. According to some embodiments, the embolic capture device is flexible and has the overall outer shape of a non-traumatic stent, and is available in various lengths and diameters, is thin-walled, and / or is radiopaque. In some embodiments, the stent is configured to be accurately delivered, retrieved, and repositioned. In some embodiments, the stent is delivered via a microcatheter and is flexible enough to be placed within a small tube, but has sufficient radial force to conform to the geometry of the vessel wall when deployed.

[0027] In another aspect, the present teachings disclose an embolus capture device having an elongated delivery profile. In some embodiments, the embolus capture device has an expanded deployed profile. As will be described in detail below, in some embodiments, the embolus capture device can have a straight, elongated, thin delivery configuration suitable for delivery via a delivery system. In some embodiments, the deployed configuration of the embolus capture device substantially engages the blood vessel in which the device is deployed. When the embolus capture device of the present teachings is used to retrieve an embolus, a positioning wire is first passed into the blood vessel across the blood clot. A microcatheter is then passed over the positioning wire and its distal end is positioned distal to the blood clot. The positioning wire is then removed, followed by a pusher shaft that couples to the proximal end of the elongated embolus capture device that extends through the lumen of the microcatheter. While holding the elongated embolus capture device stationary, the clinician withdraws the microcatheter in the proximal direction to remove the device's sheath. Once outside the microcatheter, the embolus capture device expands to stretch the arterial wall, allowing blood to flow. In one embodiment, the device is deployed in the distal direction of the blood clot. In another embodiment, the device is deployed across the blood clot. In some embodiments, to retrieve the blood clot, the clinician pulls the pusher shaft in the proximal direction, pulling the embolus capture device back in the proximal direction, and the blood clot is carried to the source of a larger catheter, guide catheter, or distal access catheter (DAC).

[0028] The techniques disclosed for delivering and deploying the embodiments described herein are merely examples. It should be understood that other teachings can be used instead of or in combination with such techniques. For example, the techniques used to deploy one embodiment of the devices described herein are dependent on the specific characteristics of the device, the delivery system, and the anatomical structure in which the device is deployed.

[0029] Figures 1-26 illustrate various embodiments of the plug capture device of the present teachings. In these drawings, although a delivery system for delivering and / or retrieving such an exemplary device is not primarily shown, a pusher shaft and / or a pull wire are shown with some exemplary devices to more clearly explain their design and function.

[0030] FIG. 1 shows an embodiment of the plug capture device (10) of the present teachings in a pre-set deployed configuration. The plug capture device (10) has the outer shape of an overall stent (12) with a generally cylindrical body having an open distal end (14). The stent (12) also has a plurality of proximal struts (18), each of which has one end connected to the proximal end (16) of the cylindrical body and the other end joined to the other end of another proximal strut (18) to form a proximal hub (20). The proximal hub (20) is configured to allow a positioning wire (not shown) to extend therethrough. According to one embodiment of the present teachings, the cylindrical body of the stent (12) has an open cell structure surface with a central lumen throughout the entire device. The proximal hub (20) of the stent (12) is configured to connect to the distal end of a pusher shaft (22). In one embodiment, the pusher shaft (22) and the positioning wire are configured to extend distally and retract proximally independently of each other.

[0031] FIG. 2 illustrates another embodiment of the plug capture device (30) in a pre-set deployed configuration. Similar to the embodiment shown in FIG. 1, the plug capture device has the outer shape of an overall stent (32) with a generally cylindrical body. Different from the previous embodiment, both the distal end (34) and the proximal end (36) of the stent (30) have a plurality of struts (38) that become hubs (40, 44). According to some embodiments, the proximal hub (40) is coupled to the distal end of a pusher shaft (42). According to some embodiments, the proximal hub (40) further enables a positioning wire (not shown) to extend therethrough. According to some embodiments, the distal hub (44) is also configured to enable a positioning wire (not shown) to extend therethrough. In one embodiment, the pusher shaft (42) and the positioning wire are configured to extend distally or retract proximally independently of each other.

[0032] Referring further to FIGS. 1-2, although not shown, the plug capture devices (10, 30) are configured to be delivered through a microcatheter (not shown). In such a delivery process, the distal end of the pusher shaft (22, 42) is coupled to the proximal hub (20, 40) of the plug capture device (10, 30). The proximal end of the pusher shaft (20, 40) is controlled by a clinician. By operating the pusher shaft (20, 40), the stent (12, 32) can be distally extruded out of the microcatheter as needed and retracted proximally back into a larger catheter.

[0033] According to one embodiment of the present teachings, the embolus capture device expands when deployed in vivo. In one embodiment of the present teachings, the embolus capture device expands radially due to the elastic properties of the material when deployed. In another embodiment, such radial expansion is achieved by pre-set thermal shape memory of the material of the device. In yet another embodiment, such radial expansion is achieved manually via an inflatable balloon. In some embodiments, the embolus capture device is made of stainless steel, nitinol, titanium, elgiloy, vitallium, Mobilium, Ticonium, Platinore, stellite, tantalum, platinum, hastelloy, CoCrNi alloy (e.g., trade name Phynox), MP35N or CoCrMo alloy, any other metal alloy or a mixture thereof.

[0034] According to some embodiments of the present teachings, the embolus capture devices (10, 30) have a stent-like shape. In some embodiments, the stent-like embolus capture device has a cell structure that allows it to contract while the stent is being delivered and expand when deployed. FIGS. 3A-3H illustrate a plurality of embodiments of the cell structure design on a cylindrical body. FIG. 3A illustrates one embodiment of the cell design. As shown, most of the cells (52) in the cylindrical body are closed and the cells (54) at one end of the stent are open. The size of the cells is generally uniform throughout the stent and the shape of each cell (52) is nearly a square shape. FIG. 3B illustrates another embodiment of the cell design. Similar to that described in FIG. 3A, the stent generally has closed cells (56) of uniform size and open cells (58) at one end of the stent. Different from the embodiment of FIG. 3A, the shape of each cell (56) is nearly an elongated diamond shape. FIG. 3C illustrates another embodiment of the cell design. Similar to that described in FIG. 3A, the stent generally has closed cells (62) of uniform size and open cells (64) at one end of the stent. Different from the embodiment of FIG. 3A, the shape of each cell (62) is nearly an elongated parallelogram shape.

[0035] As illustrated in FIGS. 3A-3B, the cell design of such an example of two embodiments is within a horizontal line (such as the example of dashed lines 50, 54 shown in FIGS. 3A and 3B) and has a cell axis generally parallel to the longitudinal axis of the stent (55, 59). The cell axis refers to a line formed by connecting the proximal and distal ends of the cell, as shown in FIGS. 3A-3B. In addition, the lengths of the upper and lower arcs of each cell are the same for all cells. With such a design, the squeezing and expanding actions of the plug capture device are generally linear and radially away from the longitudinal axis of the stent (55, 59).

[0036] An example embodiment of FIG. 3C illustrates another cell design. Similar to the example embodiment shown in FIGS. 3A - 3B, the cell axis is parallel to the longitudinal axis of the stent. Different from the example embodiment shown in FIGS. 3A - 3B, the lengths of the upper arc and the lower arc (61, 63) of each cell (62) are not the same relative to each other. Each of them (61, 63) follows a different curvature. With such a design, the squeezing and expanding actions of the plug capture device can be angled along the longitudinal axis of the device (70) as shown in FIG. 3D and can be a rotational movement along this longitudinal axis. In some embodiments, the various heights of each cell, the lengths of each cell axis, the lengths of the arcs of each cell, the squeezing movement and the expanding movement of the device can be pre - determined and controlled. For example, the higher the height of the cell, the greater the rotation of the device in the squeezing and expanding actions. In another example, the angle between the cell axis and the longitudinal axis of the device controls the direction of rotation in the squeezing and expanding actions. For example, in the case where the cell design has a cell axis angled with respect to the longitudinal axis of the stent as shown in FIGS. 3E and 3F. In such an angled design, the squeezing and expanding actions of the plug capture device can be angled along the longitudinal axis of the device (70) as shown in FIG. 3D and can be a rotational movement along the longitudinal axis. Those skilled in the art should understand that the combination of the length of the arc of the cell and the height of the cell can control the speed of rotation in the squeezing and expanding actions. FIG. 3C shows that the arc of each cell has one smooth curve, but those skilled in the art should understand that other cell arcs may be incorporated, such as those shown in FIGS. 3E and 3F.

[0037] In addition, the plug capture device may have multiple layers of stents with the same or different cell designs. For example, as shown in FIG. 3G, the inner layer (84) of the stent (80) may have a cell design that allows the inner layer (84) of the stent (80) to rotate clockwise in the expanding and contracting actions, and the outer layer (82) of the stent (80) may have a cell design that allows the outer layer (82) of the stent (80) to rotate counterclockwise in the expanding and contracting actions. Such a multi-layer device design can improve the engagement with and retrieval of blood clots.

[0038] One of ordinary skill in the art should understand that, depending on the combination of different cell and / or device designs, the device can be programmed to have various motions, such as clockwise rotation, counterclockwise rotation, zigzag motion, accelerating motion along the length of the device, and / or decelerating motion along the length of the device. Thus, the exemplary embodiments shown in FIGS. 3A - 3G and described herein should not be considered as limiting the scope of the present teachings.

[0039] Figure 3H illustrates another embodiment of the cell design. Similar to the embodiments of FIGS. 3A-3C, the stent has an overall closed cell and an open cell (96) at one end of the stent. Different from the embodiments shown in FIGS. 3A-3C, the stent has a small closed cell (92) near its closed end and a large closed cell (94) throughout from the central to the open end section. According to one embodiment of the present teachings, the larger cell (94) allows blood clots to enter the lumen inside the stent more efficiently, while the smaller cell (92) prevents smaller emboli from leaking. FIG. 3I illustrates another embodiment of the cell design. Similar to what is described in FIGS. 3A-3C, the stent has an overall closed cell of uniform size and an open cell at one end of the stent. Similar to what is described in FIG. 3A, the cells are close to a substantially square shape. In addition, some sections of the stent also have a laser cut pattern (98). In some embodiments, the stent has a portion (98) that can be heat treated towards the inside. According to one embodiment, these portions are more suitable for capturing blood clots at their predetermined positions. FIG. 3J illustrates another embodiment of the cell design. Different from the embodiments described in FIGS. 3A-3C, the stent has closed cells throughout its entire section. In some embodiments, the closed end (100) may be more suitable for capturing blood clots. FIG. 3K illustrates another embodiment of the cell design. Similar to what is described in FIG. 3H, the stent incorporates larger cells (104) to allow blood clots to enter the lumen inside the stent more efficiently, while the smaller cells (102) prevent smaller emboli from leaking. Different from the embodiment of FIG. 3H, the smaller cells (102) are incorporated into multiple sections of the stent. FIG. 3L illustrates another embodiment of the cell design. This embodiment is overall similar to what is shown in FIG. 3J, but the stent also has fingers (106) along the stent body and at the distal end of the stent to capture blood clots more firmly. In one embodiment, the fingers (106) along the stent body bend radially inwards.The fingers (106) at the distal end of the stent provide structural integrity to the device.

[0040] According to one embodiment of the present disclosure, depending on the orientation of the axial cells, while the clinician withdraws the microcatheter proximally to remove the cover of the embolus capture device and delivers and deploys the embolus capture device, the device having a cylindrical stent body exits the microcatheter either in a rotational or a linear motion. Similarly, while the clinician pulls the pusher shaft from its proximal end to retrieve the embolus, the embolus capture device having a cylindrical stent body enters the distal end of the guide catheter either in a rotational or a linear motion. Thus, in some embodiments of the present disclosure, having an embolus capture device designed to rotate intentionally during delivery, deployment, and retrieval is advantageous for the patient. For example, the cylindrical stent body can be designed such that the embolus capture device has a cell structure that engages the blood clot like a screw, as shown in FIG. 3D. In another case, having an embolus capture device with a minimal outer profile after the deployment operation is of the utmost benefit to avoid damaging the blood vessel.

[0041] Those skilled in the art should understand that any combination of cell size, cell shape, fingers for blood clot capture, and / or internal components is possible. Thus, the specific embodiments described above with reference to FIGS. 3A - 3L should not be considered as limiting the scope of the present disclosure. Additionally, instead of continuous surface stiffness, in some embodiments, depending on the cell structure, the stiffness of the device may vary from one section to another. The varying stiffness along the device body helps the stent engage the blood clot more efficiently.

[0042] In some embodiments of the present teachings, the plug capture device can be fabricated by laser cutting or acid etching a specific pattern into a pre-formed tube and then shaping it into the intended deployed configuration. In such embodiments, the plug capture device can be formed, for example, from a hollow tube grooved using a machining laser or a water drill or other methods and then expanded to form an open structure. In another embodiment, the plug capture device is formed from a wire pre-set to the desired shape, and then specific elements are connected onto the wire by any of cross-hatching, braiding, welding, or other methods of assembling rows of metal to be internally connected to form a structure such as a tube, where the wires may be adhered to each other. In one embodiment, the wires may be welded using resistance welding techniques or arc welding techniques, preferably in an inert gas environment and with a cooling control device to control the grain structure at and around the weld site. Such joints can be adjusted after the welding process to reduce the grain size, and their fatigue resistance performance can be optimized using indentation or upset forging.

[0043] According to some embodiments of the present teachings, as the plug capture device is pulled proximally, the device elongates and applies pressure to the blood clot. In the presence of a large blood clot, such an action may break the blood clot, thereby creating multiple emboli. To address such problems, the stent as shown in FIGS. 1 - 3 may be improved. One way to address the problem is to add a mesh layer with a smaller pore size to the plug capture device configured to capture smaller plugs. In one embodiment, the mesh for capturing smaller plugs is fixedly attached to a specific section of the stent. In another embodiment, the mesh is arranged in layers inside or outside the stent. In yet another embodiment, the mesh is movably incorporated into the stent.

[0044] Next, referring to FIG. 4, the mesh net (112) is fixedly coupled to the embolus capture device (32). According to one embodiment of the present disclosure, as shown in the drawings, the distal mesh net (112) is fixedly attached to the distal end of an example device as shown in FIG. 2. Such a net (112) serves to capture emboli that occur during thromboectomy. In one embodiment, the net (112) is attached to the distal end of the device (32) from the outside. In another embodiment, the net (112) is attached to the distal end of the device (32) from the inside. In one embodiment, the mesh net (112) covers the distal struts of the stent. In another embodiment, the mesh net (112) covers the distal struts and the distal portion of the stent.

[0045] According to one embodiment of the present disclosure, the mesh net is formed from wires that are pre-bent into a desired shape and then the wires are adhered to each other such that the elements are connected by welding or by an adhesive. They may be welded using resistance welding techniques or arc welding techniques, preferably in an inert gas environment and by a cooling control device for controlling the grain structure at and around the welding site. Such joints can be adjusted after the welding process to reduce the grain size, and their fatigue resistance performance can be optimized using indentation processing or upset forging.

[0046] Next, referring to FIGS. 5A-5B, here the mesh net (120) is movably coupled to the plug capture device. According to one embodiment of the present teachings, the device has two parts, namely a stent part (12) and a distal net part (120). The embodiment shown in FIGS. 5A-5B is similar to that shown in FIG. 1, but here the proximal struts are coupled to a cylindrical stent body to form a proximal hub. The proximal hub is configured to couple to a pusher shaft (22). In some embodiments, a pull wire (122) extends through the pusher shaft (22), the proximal hub, and the cylindrical stent body (12). The distal end of the pull wire (122) is coupled to the distal net part. In some embodiments, the pusher shaft (22) and the pull wire (122) move independently of each other.

[0047] Continuing with reference to FIGS. 5A - 5B, the distal mesh portion (120) also includes a plurality of struts (124). In some embodiments, the proximal ends of the struts (124) are joined to form a hub (126). In some embodiments, the distal ends of the struts (124) are joined to the distal mesh (120). In some embodiments, the pull wire (122) is joined to the distal mesh (120) at specific locations. According to some embodiments, in the deployed configuration, the distal mesh (120) has a deployed outer shape that resembles a cone or a tent shape. In some embodiments, in the deployed configuration, the distal mesh (120) has a deployed outer shape that resembles an umbrella or an umbrella framework. Similar to the stent (12), the proximal hub (126) of the distal mesh portion (120) is also configured to allow the pull wire (122) to extend therethrough. According to one embodiment of the present teachings, the pull wire (122) further extends proximally through the axial lumen of the stent (12) and the longitudinal lumen of the pusher shaft (22) and continues to the outside of the body. In one embodiment, during delivery, the pull wire (122) extends distally, pushing the distal mesh (120) distally and compressing the distal mesh (120) and the struts (124) connected to the mesh. Thereby, the distal mesh portion (120) takes on an elongated delivery outer shape, where the struts (124) are brought closer together and grouped into one, and are positioned proximally with respect to the distal mesh (120). In another embodiment, the pull wire (122) is pulled proximally, pulling the distal mesh (120) proximally, thereby compressing the distal mesh (120) and the struts (124) connected to the mesh (120). In some embodiments, the distal mesh portion (120) takes on an elongated delivery outer shape, where the distal mesh (120) is compressed, the struts (124) are brought closer together and grouped into one, and are positioned around the compressed distal mesh (120). According to one embodiment, during delivery, the stent (12) resumes its elongated delivery outer shape while holding the compressed distal mesh (120) within the axial lumen of the stent (12) in its elongated delivery outer shape.In another embodiment, while being delivered, the stent (12) resumes its elongated delivery profile with the distal mesh (120) in its elongated delivery profile positioned in the distal direction of the collapsed stent (12).

[0048] Continuing to refer to FIGS. 5A - 5B, once deployed, the distal mesh (120) is configured to be positioned in the distal direction of the stent (12). The distance between the distal mesh (120) and the stent (12) can be adjusted based on the patient's needs. For example, while fixing and holding the stent (12), the clinician can move the distal mesh (120) further away from the stent (12) by pushing the pull wire (122) in the distal direction. Alternatively, while fixing and holding the stent (12), the clinician can also pull the pull wire (122) in the proximal direction to move the distal mesh (120) closer to the stent (12). In one embodiment, since the pusher shaft (22) and the pull wire (122) move independently of each other, the distal mesh (120) has a first configuration that axially moves distally away from the stent (12) as shown in FIG. 5A, and the distal mesh (120) also has a second configuration that partially remains within the distal opening of the stent (12) as shown in FIG. 5B. As shown in FIG. 5B, the struts (124) of the distal mesh (120) portion are retracted inside the distal opening of the stent (12), and at least a portion of the distal mesh (120) remains outside the stent (12). During treatment, the clinician first deploys the stent (12) and then fixes the distal mesh (120) portion. Once the stent (12) engages a blood clot, the clinician then moves the distal mesh (120) closer to the stent (12) to collect emboli, blood clot fragments, or residues. Such an operation can be achieved by fixing and maintaining the stent (12) while retracting the distal mesh (120) portion, or by fixing and maintaining the distal mesh (120) portion while advancing the stent (12).

[0049] Figures 5A-5B illustrate a distal mesh that is generally conical in shape, but one of ordinary skill in the art should understand that different outer shapes may be incorporated to achieve the same functional purpose. For example, as shown in Figure 5C, the distal mesh may be in the form of a mesh tube (130) having a closed distal end (132) and an inclined proximal end (134) that is angled with respect to the longitudinal axis of the mesh tube (130). Thus, one of ordinary skill in the art should understand that such specific example embodiments shown in the drawings and described herein should not be considered as limiting the scope of the present teachings. According to one embodiment of the present teachings, the distal mesh (130) as shown in the example embodiments of Figures 4-5 can be made of a metallic material such as nitinol, cobalt, chromium, or other suitable superelastic materials.

[0050] Figure 6 illustrates a variant of the example embodiment shown in Figures 5A-5B. All other elements are the same as those described with reference to Figures 5A-5B, but in this example embodiment, instead of a distal mesh, the struts of the distal mesh portion are joined to a film (140) at its distal end. According to one embodiment, the film (140) can block blood flow. Such a configuration allows the device to hold emboli flowing from the distal direction. Compared to a mesh, the film (140) can be made of less material with fewer pores. In one embodiment, the film (140) may be made of a polymeric material such as a polyolefin family, nylon, or Pebax.

[0051] Figures 4-6 illustrate an example embodiment in which only one distal mesh is incorporated into the stent structure. Those skilled in the art should understand that in some embodiments, two or more mesh nets may be incorporated. For example, FIG. 7 illustrates an example stent (12) shown in FIG. 1, but the distal mesh (152) incorporates not only one but three additional mesh nets (154). As shown in FIG. 7, each mesh (152, 154) has a bottom edge connecting to the stent (12), and the central portion of the mesh extends distally away from its bottom edge, so that the mesh nets (152, 154) form a substantially conical shape. According to one embodiment of the present teachings, the mesh nets (152, 154) shown in this example embodiment have a pre-formed conical shape, which is configured to contract during percutaneous delivery and take an expanded outer shape upon deployment. As shown in FIG. 7, each mesh net (152, 154) is housed inside the axial lumen of the stent.

[0052] According to one embodiment of the present teachings, the pull wire (122) is configured to extend through each mesh as shown, for example, in FIG. 8 and connect to the distal tip of each mesh. As shown in FIG. 8, the pull wire (122) extends along the longitudinal axis of the stent (12), and the distal end of the pull wire (122) is coupled to the distal tips of the distal meshes (152, 154). Each mesh net housed inside the stent (12) is also coupled to a specific section of the pull wire (122). During clot retrieval, all the mesh nets (152, 154) act as caps for capturing debris of the thrombus. When the clinician pulls on the proximal end of the pull wire (122), the pulling force in the proximal direction is transmitted to the mesh nets (152, 154), enabling the stent to more efficiently contain / capture the clot and minimizing the possibility of clot leakage.

[0053] Figures 9A - 9B illustrate another embodiment described with reference to Figures 5A - 5B. In this embodiment, instead of a conical or umbrella - framed distal mesh, the distal mesh (162) has a sealed 3D outer shape, but all other elements are the same as those described with reference to Figures 5A - 5B. In one embodiment, the distal mesh (162) has a generally round or slightly elongated ball shape, and the pull wire (122) is coupled at a proximal location of the ball. In another embodiment as shown in Figures 9A - 9B, the distal mesh (162) is rugby - ball shaped. During delivery, the distal mesh of the sealed 3D outer shape (162) collapses and becomes elongated either disposed distally of the collapsed stent (12) or disposed within the axial lumen of the collapsed stent (12). When deployed, the distal mesh (162) of the sealed 3D outer shape expands to a shape that captures a pre - set plug.

[0054] Figures 9A - 9B show two deployed configurations of a plug - capturing device that includes a stent (12) and a distal mesh (162). Similar to that described with reference to Figures 5A - 5B, in one embodiment, since the pusher shaft (22) and the pull wire (122) move independently of each other, the distal mesh portion (162) has a first configuration that axially moves distally away from the stent (12) as shown in Figure 9A, and the distal mesh portion (162) also has a second configuration that partially remains within the distal opening of the stent (12) as shown in Figure 9B. As shown in Figure 9B, at least the proximal portion of the distal mesh portion (162) is drawn into the distal opening of the stent (12), and at least the distal portion of the distal mesh portion (162) remains outside the stent (12). According to one embodiment of the present teachings, the distal mesh portion (162) is configured to act as a distal protector, a flow restrictor, a stopper for a laser stent, and ultimately a cleaner when retrieved.

[0055] Figure 10 illustrates a variant of the embodiment shown in FIGS. 9A-9B. In this embodiment, the distal mesh portion (162) in this embodiment is created by a plurality of sealed 3D mesh nets (162) that are coupled to each other, but all other elements are the same as those described with reference to FIGS. 9A-9B. Three sealed mesh nets (164) are shown in FIG. 10, but there may be cases where two, four or even more sealed mesh nets (164) are incorporated, and thus those skilled in the art should understand that the scope of the present teachings should not be limited to what is illustrated in the drawings. In one embodiment, as illustrated in FIG. 10, the pull wire (122) extends through the proximal sealed mesh net (164), and the two proximal sealed mesh nets (164) are coupled to the proximal end of the most distal sealed net (162) in a state where they are coupled to each other. In an alternative embodiment, the pull wire (122) is coupled to the proximal end of the most proximal sealed mesh net (162) in a state where all the sealed mesh nets (164) are coupled to each other.

[0056] Since two adjacent sealed mesh nets (164) are coupled to each other, according to one embodiment of the present teachings, the distal end of the proximal sealed mesh net (164) is coupled to the proximal end of the distal sealed mesh net (162). The coupled portion between the two sealed mesh nets (164) is configured such that the pull wire (122) can extend therethrough. In one embodiment, each sealed mesh net (162, 164) unfolds independently of each other. Alternatively, all the sealed mesh nets (162, 164) unfold simultaneously. In one embodiment, the shape and size of the sealed mesh nets (162, 164) can be the same. Alternatively, the shape and size of the sealed mesh nets (162, 164) may be different from each other.

[0057] Unlike that described with reference to FIGS. 9A-9B, the size of the sealed mesh nets (162, 164) is configured in the second configuration such that all the sealed mesh nets once deployed can slide back inside the axial lumen of the stent. The sealed mesh nets (162, 164) help to securely hold the blood clot in place once it is captured by the stent and prevent the blood clot from breaking apart.

[0058] Figure 11 illustrates one embodiment of an embolus capture device in which a sealed mesh network (172) is movably coupled to an embolus capture device such as that shown in FIG. 2. Similar to that described with reference to FIG. 2, the proximal struts couple with the cylindrical stent body to form a proximal hub, and the distal struts couple with the cylindrical stent body to form a distal hub. As described above, the proximal hub is configured to couple with a pusher shaft (22), and the distal hub is configured to couple with a distal mesh portion (172). Similar to that described with reference to FIGS. 9-10, the distal mesh portion (172) includes at least one sealed 3D mesh network. According to one embodiment of the present teachings, two or more sealed mesh networks (172) constitute the distal mesh portion. The configuration of the plurality of sealed mesh networks is similar to that described above, such as with reference to FIGS. 9-10. Similar to that described with reference to FIGS. 9A-9B, the distal mesh portion (172) has a first configuration that constricts radially and a second configuration that expands radially as shown in FIG. 11. According to one embodiment of the present teachings, the proximal stent body (32) is configured to engage a blood clot and, in some cases, break the blood clot apart, and the distal mesh portion (172) is configured to capture and remove debris that occurs during treatment. In one embodiment, the stent portion (32) of the device is relatively more rigid than the distal mesh portion (172) of the device. Although the distal mesh portion (172) shown in FIGS. 9-11 is described as having mesh balls, those skilled in the art should understand that different configurations may be used, if desired, to enhance the effect. For example, the distal mesh portion may sometimes be made of a braided mesh or a film.

[0059] Figures 12A - 12B illustrate another embodiment of a plug capture device where the distal mesh portion is the outer shape of the mesh tube (182). The embodiment shown in Figures 12A - 12B also has a stent (32) similar to that described with reference to Figure 2. Different from that described with reference to Figures 9 - 11, the mesh tube (182) in this embodiment is in the overall shape of a test tube with a proximal opening and a distal closed end. The distal end of the pull wire (122) is attached to the distal closed end of the mesh tube (182). Similar to that described with reference to Figures 9 - 11, in one embodiment, since the pusher shaft and the pull wire (122) move independently of each other, the distal mesh portion (182) has a first configuration where it moves axially distally away from the stent (32) as shown in Figure 12A, and the distal mesh portion (182) also slides over the stent (32) as shown in Figure 12B and has a second configuration where the mesh tube (182) covers at least a portion of the stent (32). In the second configuration as shown in Figure 12B, the outer mesh tube (182) covers the inner layer of the stent. In one embodiment, the mesh tube (182) has the same length as the stent (32). In another embodiment, the mesh tube (182) has a different length from the stent (32). In one embodiment, the mesh tube (182) has an inner diameter that relatively matches the outer diameter of the stent (32). In one embodiment, the mesh tube (182) has a constant diameter throughout its entire length. In another embodiment, the mesh tube (182) changes diameter from one section to another. In one embodiment, the proximal end of the mesh tube (182) has an outer diameter in a straight line generally perpendicular to the longitudinal axis. During retrieval of the plug, when the stent body engages a blood clot, the clinician then pushes the stent body distally towards the mesh tube (182) to prevent any blood clot fragments from leaking into the blood flow.

[0060] Figures 13A-13B illustrate another embodiment of the present teachings. Unlike the embodiment shown in Figures 12A-12C, the stent (32) is configured to be secured to a mesh sleeve layer outside of the stent (32) body. In one embodiment, the mesh sleeve (192) has the same length as the stent (32) as shown in Figure 13A. In another embodiment, the mesh sleeve (192) is longer than the stent (32) as shown in Figure 13B. According to one embodiment of the present teachings, once the mesh sleeve (192) covers the outside of the stent (32) body, the device will have an increased surface area and the radially outward force will increase. In another embodiment, when the mesh sleeve (194) is longer than the stent (32) body as shown in Figure 13B, the proximal portion of the mesh sleeve (194) covers the outside of the stent (32) body while the distal portion of the mesh sleeve (194) extends to cover the distal end of the stent (32) body. According to one embodiment of the present teachings, the distal portion of the mesh sleeve (192, 194) is configured to capture and remove fragments of thrombus that occur during treatment. Similar to the embodiments described above, the stent (32) portion of the device is relatively more rigid than the mesh sleeve (192, 194) outside of the device.

[0061] Next, referring to FIGS. 14-15, a stent stabilization mechanism is employed in the plug capture device to prevent small plugs from leaking out of the stent and causing complications. According to some embodiments of the present teachings, once a blood clot is captured, while the blood clot is being retrieved, a retrieval force is applied to the proximal end of the stent, the stent elongates, and its overall diameter shrinks. Thus, to stabilize the stent and prevent the adhesion force of the stent wall from weakening, according to one embodiment of the present teachings, by incorporating stabilizing struts, the adhesion to the wall is maintained, and further, the adhesion to the wall becomes stronger while retrieving with the stent. According to some embodiments of the present teachings, the stabilizing struts may be used to support the stent structure. As shown in FIG. 14, the stabilizing strut (202) extends from the peripheral wall of the stent (32), extending distally and radially inwardly at a certain angle. The distal end (204) of the stabilizing strut (202) terminates at a position near the axial center of the stent (32). As shown in FIG. 14, the distal end of the first stabilizing strut (202) contacts the distal end of another stabilizing strut (202) extending from the same section of the peripheral wall of the stent (32) in a similar manner. Both ends meet at a position near the axial center of the stent (32). In one embodiment, two stabilizing struts (202) are joined to form one set. In another embodiment, three or more stabilizing struts (202) are joined to form one set. In one embodiment, two sets of stabilizing struts (202) are incorporated into the stent (32), one set of struts (202) extends from the most distal end of the stent (32), and the other set of struts (202) extends from the most proximal end of the stent (32). In another embodiment, three or more sets of stabilizing struts (202) are incorporated, the first set of struts (202) extends from the most distal end of the stent (32), the second set of struts (202) extends from the most proximal end of the stent (32), and the third set of struts (202) extends from a section of the stent (32) between the proximal end and the distal end.One of ordinary skill in the art should understand that more than four sets of stabilization struts (202) may be incorporated, such as in the example embodiment shown in FIG. 14 where four sets of stabilization struts (202) are used.

[0062] According to some embodiments of the present teachings, one end of each stabilization strut (202) is joined to couple to the shaft of the pull wire (122) as shown in FIG. 15. In one embodiment, the distal end of each set of stabilization struts (202) is joined to a particular section of the shaft of the pull wire (122) as shown in FIG. 15. During retrieval, a proximally-directed pulling force is applied to the pull wire (122), and the stabilization strut (202) transmits the pulling force radially, which causes the stent wall to open so that the stent contacts the blood clot more. FIG. 16 illustrates an alternative embodiment to FIG. 15, where the proximal struts of the stent have been removed to enhance the efficiency of the mechanical thrombectomy process.

[0063] Figures 17A - 17B illustrate another embodiment in which a stabilizing strut is incorporated into a plug capture device. According to some embodiments of the present teachings, the stent (32) incorporates at least one directional strut (220). The proximal end (222) of the strut (220) is connected to the distal end of the pusher shaft (22), and the distal end (224) of the strut (220) is connected to a specific position on the pull wire (122). The central section of the strut (220) has a junction (226). Such a junction (226) is attached to the peripheral wall inside the stent (32). As shown in Figure 17A, the pull wire (122) extends through the longitudinal lumen of the pusher shaft (22). The pusher shaft (22) extends distally through the proximal hub of the stent (32) with the distal end of the pusher shaft (22) inside the axial lumen of the stent (32). The pusher shaft (22) and the pull wire (122) slide independently of each other. According to one embodiment of the present teachings, as the distal end of the pusher shaft (22) moves proximally away from the distal end of the pull wire (122), both ends (222, 224) of the strut move away from each other. When the strut (220) straightens at the junction, the stent (32) walls are radially pulled relative to each other. According to another embodiment of the present teachings, as the distal end of the pusher shaft (22) moves distally towards the distal end of the pull wire (122), both ends (222, 224) of the strut move closer to each other. When the strut (220) bends at each junction, the strut (220) pushes the stent (32) wall radially outward. Such a mechanism enables a clinician to adjust the overall size of the stent (32) by manipulating the relative positions of the pusher shaft (22) and / or the pull wire (122). According to some embodiments of the present teachings, such a design enables a clinician to control the overall diameter of the stent by increasing or decreasing the wall adhesion as needed during clot retrieval.In addition, this will provide the clinician with the operability to pass through blood vessels of various diameters and also provide a response force according to the size of the blood clot.

[0064] In additional embodiments of the present teachings, a mesh network (228) may be incorporated into embodiments shown and described with reference to FIGS. 14-17, similar to those described with reference to FIGS. 4-8. For example, FIG. 18 illustrates a distal network incorporated into the embodiment shown and described with reference to FIG. 15. FIG. 19 illustrates a plurality of mesh networks (230) incorporated to cover a set of a plurality of stabilizing struts (202) combined with a distal network incorporated into the embodiment shown and described with reference to FIG. 15. FIG. 20 illustrates a distal network (232) incorporated into the embodiment shown and described with reference to FIG. 17A.

[0065] FIG. 21A illustrates another embodiment of an embolus capture device (250) according to the present teachings. As illustrated in FIG. 21A, in one example, a stent (252) has a discontinuous pattern (254) across the entire stent surface. As shown, the stent (252) has continuous portions (256) and discontinuous portions. The continuous portions (256) have stent surface features similar to those described above. The discontinuous portions (254) are designed to allow a blood clot to travel through the lumen inside the stent (252). In one embodiment, the discontinuous portions (254) are helically spaced along the inner lumen surface of the stent. For example, the helical openings are at least one rotation along the stent surface. In another embodiment, the discontinuous portions (254) are linearly spaced along the inner lumen surface of the stent. In one embodiment, the discontinuous portion is created by one continuous opening. In another embodiment, the discontinuous portion is created by two or more helical openings connected to each other. In one embodiment, the discontinuous portion occupies more than 50% of the inner lumen surface. In another embodiment, the discontinuous portion occupies less than 50% of the inner lumen surface. In one embodiment, the discontinuous portion is disposed from the proximal end to the distal end of the stent. In another embodiment, the discontinuous portion is located only around one of the distal section, proximal section, and / or central section of the stent. In one embodiment, the discontinuous portion has an opening sized similar to the blood clot to be captured. Such a design can achieve a more effective engagement with the embolus. For example, as the stent is retracted in the proximal direction, the blood clot enters the inner lumen of the stent as soon as it contacts the discontinuous portion of the stent. Additionally, as described above, as shown in FIG. 21B, a mesh may be further incorporated into the continuous portion of the stent to more firmly capture the blood clot.

[0066] Figure 22A illustrates another embodiment of a plug capture device (260) according to the present teachings. As illustrated in Figure 22A, one example of a device (260) has a plurality of ball-shaped plug capture portions (262) where one portion is connected to another portion in a linear fashion. According to one embodiment, as shown in Figure 22A, each ball-shaped capture portion (262) has four struts (264) in the outer shape of an arc that extends from the proximal end of the ball portion (262) to the distal end of the ball portion (262). In addition, the ball-shaped portion (262) is covered by a mesh net (268). The proximal end of the proximal ball portion (262) is configured to couple to a pusher shaft. Although four struts (264) are illustrated in Figure 22A, one of ordinary skill in the art should understand that fewer than four or more than four struts may be used to construct each ball-shaped portion. In some embodiments, the ball-shaped portion may be entirely made of a mesh net, i.e., there may be no struts. In addition, although three coupled ball-shaped portions are shown herein, one of ordinary skill in the art should understand that more than three or fewer than three ball-shaped portions may be incorporated to create a complete plug capture device. In addition, although all three ball-shaped portions (262) are shown as being covered by a mesh net (268), one of ordinary skill in the art should understand that one or more ball-shaped portions may have exposed struts without a mesh cover, such as that shown in Figure 22B. In one embodiment, all ball-shaped portions within the device may have the same configuration, such as the shape and size of each ball, with or without struts, the number of struts incorporated into each ball portion, with or without a mesh cover, the density of the mesh cover, the characteristics of the materials used, the type of materials used, etc. One of ordinary skill in the art should understand that all ball-shaped portions within the device may also have different configurations.

[0067] FIG. 23 illustrates another embodiment of the plug capture device (270) according to the present teachings. As illustrated in FIG. 23, the device has a braided plug capture portion with proximal struts (274). All of the proximal struts (274) together form a proximal hub (276). The distal end of the pusher shaft (22) is coupled to the proximal hub (276) of the device (270). According to one embodiment, the device body may be similar to the mesh sleeve described above, such as that described with reference to FIGS. 13A-13B. When the clinician pulls the pusher shaft (22) in the proximal direction, the braided portion elongates while retrieving the blood clot and captures the blood clot.

[0068] FIG. 24 illustrates another embodiment of an embolus capture device (280) in which most of the device is made of a mesh network according to the present teachings. As illustrated in FIG. 24, the device has a plurality of mesh networks (282) in the overall shape of a basket. Each of the baskets (282) is coupled to a pusher shaft (22) via struts (284). The struts (284) are coupled to the open edge of the strut (284) at its distal end and to a specific location on the pusher shaft (22) at its proximal end. As shown in FIG. 24, the struts (284) connecting to the first basket extend radially away from one side of the pusher shaft (22), and the struts (284) connecting to an adjacent basket (282), i.e., the second basket (282) in the distal direction of the first basket (282), extend radially from the opposite side of the pusher shaft (22). The first basket (282) is proximal to the second basket (282). The first basket (282) partially covers the opening of the second basket (282) as shown in FIG. 24. For example, at least a portion of the first basket (282) extends beyond the opening surface of the second basket (282), while two adjacent baskets (282) do not have direct contact with each other. According to one embodiment of the present teachings, such a design is repeated the desired / designed number of times. FIG. 24 shows seven mesh baskets that make up the entire embolus capture device, but those skilled in the art should understand that more than seven or fewer than seven baskets may be used to complete the embolus capture device. Thus, an example embodiment shown herein should not be considered as limiting the scope of the present teachings. In addition, according to one embodiment of the present teachings, each basket is configured such that the pusher shaft can extend therethrough. The distal end of the pusher shaft (22) is coupled to the distal end of the most distal basket. By extending the pusher shaft distally or retracting it proximally, the device is delivered, deployed, and once engaged with and captured by a blood clot, retrieved.

[0069] FIG. 25 illustrates another embodiment of a plug capture device (290) according to the present teachings. As illustrated in FIG. 25, the device has two components, a distal cap (292) and a proximal cap (294). In one embodiment, the distance between the proximal cap (294) and the distal cap (292) is preset such that the distal cap (292) is coupled to the distal end of the pusher shaft (22) and the proximal cap (294) is coupled to a particular position on the pusher shaft (22) from a particular distance in the proximal direction relative to the distal cap (292). According to another embodiment of the present teachings, the distal end of the pusher shaft (22) is coupled to the proximal cap (294) and the distal end of the pull wire (122) is coupled to the distal cap (292). Similar to that described above, the pull wire (122) extends through the longitudinal lumen of the pusher shaft (22). Since the pusher shaft (22) and the pull wire (122) slide independently of each other, the distance between the proximal cap (294) and the distal cap (292) is adjustable according to the relative distance between the distal end of the pusher shaft (22) and the distal end of the pull wire (122).

[0070] In use, the distal cap (292) is deployed in the distal direction of the blood clot, and the proximal cap (294) is deployed in the proximal direction of the blood clot. The blood clot is captured while retrieving both the distal cap (292) and the proximal cap (294). According to one embodiment of the present teachings, each cap (292, 294) is constructed with support struts covered by either a mesh layer or a film layer. In another embodiment, each cap (292, 294) is constructed of only a mesh layer. In one embodiment, at least one of the proximal cap (294) and the distal cap (292) is configured to self-expand when exposed at the treatment site. In another embodiment, at least one of the proximal cap (294) and the distal cap (292) is configured to be manually deployed at the treatment site. For example, the distal cap (292) may be constructed with an umbrella-like mechanism and deployed with such a mechanism. As in the embodiment shown in FIG. 25, the distal cap (292) has a plurality of support struts with its proximal end slidably attached to a pull wire (122) and its distal end attached to a mesh framework, and by pushing the proximal ends of the support struts in the distal direction, the mesh framework expands radially.

[0071] Figures 26A-26B illustrate another embodiment. Figure 26A illustrates that in addition to the embolic capture stent (300), a flow restriction mechanism (302) is added to the proximal end of the stent (300). According to one embodiment of the present teachings, the flow restriction mechanism (302) reduces the likelihood that a blood clot will break apart as a result of the reopening of blood flow. Figure 26B illustrates that in addition to the embolic capture stent (310), a flow restriction mechanism (312) is added to the proximal end of the stent (310) and a distal protection mechanism (314) is added to the distal end of the stent (310). According to one embodiment of the present teachings, the distal protection mechanism captures fragments of emboli that occur during treatment. As shown in Figures 26A-26B, both the distal protection mechanism (314) and the proximal flow restriction mechanism (312) are coupled to respective ends of the stent body (310) and have a diameter slightly larger than the overall diameter of the stent body (310). Those skilled in the art should understand that the distal protection mechanism (314) and the proximal flow restriction mechanism (312) may both have a size that is the same as or slightly smaller than the size of the stent body (310). Thus, what is shown in Figure 26B should not be considered as limiting the scope of the present teachings. In addition, Figures 26A-26B illustrate that both the distal protection mechanism (314) and the proximal flow restriction mechanism (312) are in a spherical configuration, but those skilled in the art should understand that other outer shapes suitable for achieving the same functional purpose may be incorporated. In one embodiment, both the distal protection mechanism (314) and the proximal flow restriction mechanism (312) may be made of a mesh, film. Also, both the distal protection mechanism (314) and the proximal flow restriction mechanism (312) may be made of the same material as each other or different materials and / or the same material as or different materials from the stent body.

[0072] According to some embodiments of the present teachings, the mesh layer and / or film layer, such as in the form of a net, basket, tube, and / or sleeve as described above, may be made of biocompatible metal or polymer metal, polymer braiding, laser cutting mechanism, porous film, fiber, or something else. In some embodiments, a device having an overall or partial curved deployed configuration deforms during the delivery process such that the portion assumes an outer shape that is generally straight, and once it is deployed from the delivery catheter, is made of an elastic material, superelastic material, or shape memory alloy that enables it to maintain its intended outer shape in the body. In some embodiments, the device is made of stainless steel, nitinol, titanium, Elgiloy, Vitallium, Mobilium, Ticonium, Platinore, Stellite, tantalum, platinum, Hastelloy, CoCrNi alloy (e.g., trade name Phynox), MP35N, or CoCrMo alloy, or other metal alloys. Alternatively, in such embodiments, some or all of the device is made of a flexible, biocompatible material, including but not limited to polyester fibers such as ePTFE, UHMPE, HDPE, polypropylene, polysulfone, polyurethane, metal materials, Teflon-based materials such as extracellular matrix (ECM) isolated from mammalian tissue, or other bioengineered materials such as bioabsorbable polymers such as polylactic acid, polyglycolic acid, polycaprolactone, or other natural materials (e.g., collagen), or combinations of these materials well known to those skilled in the art.

[0073] According to one embodiment of the present teachings, the mesh layer / film layer as described above does not impede blood flow through the openings even when the device assumes a curved deployed outer shape. According to one embodiment of the present teachings, the size of each mesh opening and film pore can range from 40 to 300 μm. According to another embodiment of the present teachings, the opening area is 50 to 95% of the total surface area of the mesh layer. According to one embodiment of the present teachings, the mesh net is sized to have generally the same diameter as the stent, such as 1 to 6 mm, for example.

[0074] In some embodiments of the present teachings, the mesh layer of the device can be a woven, knitted, or braided tubular metal fiber made from metal strands. As used herein, the term "strand" may be a wire, thread, fiber, yarn, monofilament, cable, or cord, and such terms may be used interchangeably with each other. According to one embodiment, the wire used to form the device has an overall diameter of from approximately 0.02 mm to approximately 1 mm.

[0075] According to one embodiment of the present teachings, the mesh layer of the device is fabricated and then shaped into its final configuration. In one embodiment, when a highly stretchable elastic material such as nitinol is used, the structure is preformed into its final shape, then elastically deformed and stored while being delivered, and the shape elastically recovers after deployment. In some embodiments, the mesh layer of the device is manually expanded until it reaches its desired configuration and may be heat treated in an oven while being constrained in the desired shape to memorize the desired shape of the device. According to one embodiment of the present teachings, when deployed, the mesh layer of the device expands due to the elastic properties of the material. According to another embodiment of the present teachings, when deployed, the mesh layer of the device expands due to the thermo shape memory of its pre-set material.

[0076] Those skilled in the art should understand that the devices described herein may also be used in combination with the direct injection of drugs through a catheter into the thrombus site. Such embodiments with a distal mesh may limit the action of pharmaceuticals such as tPA (tissue plasminogen activator) that lyses blood clots and acts locally and directly on the blood clots. Specifically, the distal mesh of the device creates a closed space that prevents tPA from circulating throughout the body. Such a design also has the effect of blocking blood flow, thus preventing further bleeding of the blood, interfering with the injection of drugs, and preventing blood from being aspirated outside the tissue. For example, the pusher shaft may be configured to excrete tPA or any therapeutic agent. Such embodiments with a distal mesh are configured such that the space between the stent body and the mesh, or the space between the two caps, forms a closed outer shape that prevents tPA from circulating throughout the body. In such a situation, after a certain period of time, the thrombus will be dissolved by the drug, i.e., by aspiration, and / or retrieved by the thrombus capture device.

[0077] FIG. 27 illustrates another embodiment of the present teachings, where the embolus capture device (320) has a stent body (322) and a helical coil (324) inside the axial lumen of the stent body (322). As shown in FIG. 27, the helical coil (324) is made from a continuous wire wound in a helical shape so as to be substantially conical. The proximal loop of the coil is coupled to the inner lumen wall of the stent body (322). In one embodiment, the proximal loop of the coil is coupled to the proximal section of the stent body (322). In another embodiment, the proximal loop of the coil is coupled to the central section of the stent body (322). During delivery, the coil (324) remains inside the elongated stent body and is configured to be extended into an elongated straight shape. When deployed, the coil (324) assumes a helically wound conical shape with its distal end remaining inside the axial lumen of the stent (322). In one embodiment, the helical coil (324) can reduce the possibility that blood clots break apart and become distal emboli by holding the blood clots inside the stent body. In one embodiment, the coil may be made of the same material as the stent body or a different material. In another embodiment, the coil may have the same flexibility as the stent body or a different flexibility. Additionally, the conical shape as illustrated in FIG. 27 is merely an example, and those skilled in the art should understand that the overall length of the coil, the inclination angle of the cone, and the tightness of each winding may all vary to achieve the intended functional purpose.

[0078] Figures 28A - 28C illustrate another embodiment of a plug engagement device (350). Such a device is used to engage a blood clot for more efficient retrieval. Figure 28A illustrates the distal portion of a guide wire (122) with a ribbon (352) wound around it in a helical manner. Figure 28A illustrates the device in a delivery configuration where the ribbon (352) is tightly wound around and not expanded. According to one embodiment of the present teachings, the ribbon (352) is configured to radially expand by an actuating mechanism and engage blood clot material. Since the ribbon (352) is wound in a helical manner, as it expands, a portion of the ribbon (352) remains within the blood clot and a portion of the ribbon (352) extends outside the periphery of the blood clot. This enables the device (350) to firmly engage the blood clot. At this point, the device (350) can be retracted proximally, with or without the assistance of a microcatheter / catheter, to carry the blood clot outside the body.

[0079] According to one embodiment of the present teachings, the expansion of the ribbon is achieved by a pull wire (not shown) coupled to the proximal end of the ribbon (352). As the clinician extends the pull wire distally, the ribbon (352) is released from the guide wire and expands radially. In one embodiment, the pull wire extends together with the guide wire. In another embodiment, the pull wire extends within the longitudinal lumen of the guide wire, exits at a specific location, and couples to the proximal end of the ribbon (352). Such a pull wire extends separately from the guide wire. By pulling the pull wire proximally, the device returns to its elongated delivery configuration. By pushing the pull wire distally, the device transitions to its expanded configuration.

[0080] In another embodiment of the present teachings, the expansion of the ribbon (352) is achieved by shape memory characteristics. Such a ribbon (352) may be heat treated to assume a specific shape. When at human body temperature, such a ribbon (352) can return to its pre-set shape. The ribbon (352) may also be configured to geometrically respond to an input of energy, such as an electric current or the wavelength of light. In yet another embodiment, the ribbon may incorporate a combination of two or more of such mechanisms.

[0081] According to one embodiment, the expansion level of the ribbon may be pre-set or may be adjustable after placement. In some embodiments of the present teachings, the cross-section of the ribbon may be circular, rectangular, triangular, elliptical, other suitable shapes, or combinations thereof as long as it is suitable for its use. In some embodiments, the ribbon may have a hollow outer shape or a solid outer shape. Those skilled in the art should understand that the various outer shapes of the ribbon may result in various interaction characteristics between the device and the blood clot.

[0082] One such example embodiment provides an embolism engagement device that can perform thrombectomy without the aid of a microcatheter. Thus, the embodiments of the present teachings can be used to reduce vascular trauma, improve the effect in tortuous portions, increase the success rate of treatment, and also reduce the possibility of losing a blood clot in tortuous portions.

[0083] Next, referring to FIGS. 28B-28C, a plurality of such ribbons (352) are wound along a guide wire. FIG. 28B provides a constricted delivery profile. FIG. 28C provides an expanded deployed profile. According to one embodiment of the present teachings, all ribbons (352) have the same shape, size, pitch, and cross-sectional profile, are made of the same material, are incorporated with the same deployment mechanism, and may expand to the same degree. In another embodiment, each ribbon may have a different shape, size, pitch, and cross-sectional profile, be made of a different material, be incorporated with a different deployment mechanism, and may expand to a different degree. According to one embodiment of the present teachings, all ribbons (352) deploy simultaneously upon reaching the treatment site. In another embodiment, at least one ribbon deploys at a different pace or at a different time than the rest of the ribbons (352). FIGS. 28B-28C show two ribbons (352) on the guide wire, but one of ordinary skill in the art should understand that more or fewer than two ribbons (352) may be incorporated as long as the same desired function is achieved.

[0084] According to one embodiment of the present teachings, a radiopaque marker is used to visualize the embolization capture device using a radiographic device such as an x-ray, magnetic resonance, ultrasound, or other imaging technique. The markers disclosed herein may be applied at both ends of any part of the device or even on the delivery system of the device. The radiopaque marker can be placed and fixed on the device by sewing, adhering, implanting, riveting, or other means. The radiopaque marker may be formed of tantalum, tungsten, platinum, iridium, gold, an alloy of these materials, or other materials known to one of ordinary skill in the art. The radiopaque marker may also be a cobalt, fluorine, or many other paramagnetic materials or other MR visible materials known to one of ordinary skill in the art.

[0085] In addition, the delivery system may also be designed for aspiration purposes. For example, the pusher shaft is configured with an aspiration chamber. Such a chamber is configured to open for aspiration. When the distal end of the pusher shaft is delivered to the treatment site, the clinician can connect a suction pump or syringe to the Pull Hypotube and aspirate blood clots. In some embodiments, the surface of the pusher shaft with the aspiration chamber is smoothed to enhance the efficiency of aspiration.

[0086] Various embodiments are illustrated and described herein by way of example, and those skilled in the art will understand that variations can be made without departing from the spirit and scope of the present teachings. It is understood that the present teachings are capable of other embodiments or of being practiced or carried out in various other ways. It should also be understood that the terminology and phraseology employed herein are for the purpose of description and should not be regarded as limiting.

[0087] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this 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 present patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Claims

1. 1. An embolus capture system, comprising: a cylindrical stent body having an axial lumen, a plurality of distal struts coupled to a distal end of the cylindrical stent body to form a distal hub, and a stent stabilization mechanism; a pusher shaft having a longitudinal lumen, the pusher shaft configured to extend distally through a proximal end of the cylindrical stent body with a distal end of the pusher shaft within the axial lumen of the cylindrical stent body; a pull wire configured to extend through the longitudinal lumen of the pusher shaft, the axial lumen of the cylindrical stent body, and a distal hub of the cylindrical stent body, the pusher shaft and the pull wire configured to extend distally and retract proximally independent of one another; An embolus capture system comprising:

2. The embolism capture system of claim 1 , wherein the cylindrical stent body further comprises a plurality of proximal struts coupled to a proximal end of the cylindrical stent body to form a proximal hub.

3. 3. The embolism capture system of claim 2, wherein the pusher shaft is configured to extend distally through a proximal end of the cylindrical stent body with a distal end of the pusher shaft within an axial lumen of the cylindrical stent body.

4. 2. The embolism capture system of claim 1, wherein the stent stabilization feature of the cylindrical stent body comprises a first pair of stabilization struts extending distally and radially inwardly at an angle from a peripheral wall of the cylindrical stent body toward an axial lumen of the cylindrical stent body, both distal ends of the first pair of stabilization struts joining together at a location proximate to an elongated axis of the cylindrical stent body.

5. The embolism capture system of claim 4 , wherein both distal ends of the first pair of stabilizing struts are coupled to the pull wire.

6. 5. The embolus capture system of claim 4, wherein the stent stabilization feature of the cylindrical stent body comprises a second pair of stabilization struts, both proximal ends of the second pair of stabilization struts extending from a peripheral wall of the cylindrical stent body distal to the distal ends of the first pair of stabilization struts, the second pair of stabilization struts extending distally and radially inwardly at an angle toward an axial lumen of the cylindrical stent body, and both distal ends of the second pair of stabilization struts joining together at a location proximate an elongated axis of the cylindrical stent body.

7. 2. The emboli capture system of claim 1, wherein the stent stabilization mechanism of the cylindrical stent body comprises at least one directional strut, a proximal end of the directional strut connects to a distal end of the pusher shaft, a distal end of the directional strut connects to a section of the pull wire, and a central section of the directional strut is attached to an inner peripheral wall of the cylindrical stent body.

8. 8. The embolus capture system of claim 7, wherein the cylindrical stent body has a first radially contracted configuration having a first distance between the proximal and distal ends of the directional struts and a second radially expanded configuration having a second distance between the proximal and distal ends of the directional struts, the first distance being greater than the second distance.

9. 8. The embolus capture system of claim 7, wherein the embolus capture system has a first radially contracted configuration having a first distance between a distal end of the pusher shaft and a distal end of the pull wire, and a second radially expanded configuration having a second distance between the distal end of the pusher shaft and a distal end of the pull wire, the first distance being greater than the second distance.

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