Devices and methods for treating blocked blood vessels

Abstract

The present teachings provide devices and methods of engaging, capturing, and retrieving emboli. Specifically, one aspect of the present teachings provide a device with visualization design to allow a clinician to assess device delivery, deployment and emboli capture process. The device is configured to allow a clinician easily identify various view orientations after the device being positioned inside a neuro-vasculature. The device is also configured to allow a clinician accurately assess its deployment and emboli capture status. Certain embodiments of the present teachings also provides devices and methods of use thereof to percutaneously remove blood clots with minimum risks.

Description

DEVICES AND METHODS FOR TREATING BLOCKED BLOOD VESSELSDESCRIPTIONFIELD

[0001] The present teachings relate to minimally invasive catheter and methods of minimally invasive catheter delivered embolic capture devices for use in the vasculature, especially those suited for usage in the brain and vessel systems perfusing the same.BACKGROUND

[0002] Mechanical embolic capture devices seek to salvage ischemic, but not yet fully infarcted, brain by restoring perfusion through the initially occluded artery. Each class of mechanical embolic capture devices achieves recanalization through somewhat different biomechanical mechanisms.

[0003] There are three types of catheter embolic capture devices on the market - aspiration catheters to vacuum the clot out of the vessel, lytic deliver catheters to infuse the clot with targeted thrombolytic drug treatment, and mechanical thrombectomy systems that Engage and retract clot. The systems on the market may combine one or more of these attributes. There are pros and cons to each of these approaches.

[0004] The aspiration catheters employ vacuum aspiration to remove occlusive clot in acute ischemic stroke. While manual aspiration of target thrombi can be performed through any microcatheter, such as by applying suction through a bore small enough to fit within intracranial arteries. The aspiration catheters are often used in rapid single-session flow restoration for removing small, fresh, soft thrombus. However, larger and more organized thrombus can overwhelm and emboli the small aperture of a manual aspiration catheter. In addition, manual aspiration is more likely than mechanical methods to leave residual thrombus. Additionally, aspiration catheters, generally having a large profile, have difficulty in crossing lesions.

[0005] The lytic delivery catheters directed thrombolysis (CDT) is the localized delivery of lytic via a catheter to dissolve thrombus and to restore vascular flow. Although the lytic therapy offers improved outcomes versus the standard anti coagulation therapy, the lytic therapy alone is often not fast enough to resolve a critical coronaryblockage as found in STEMI or in restoring flow in peripheral vasculature. In peripheral cases, a lytic-only treatment may require extended stays in the ICU and frequent angiographic re-visualizations to check the progress. To treat a large thrombus burden of the neuro vasculature, a significant systemic dose of lytic is often used before the blockage can be fully resolved. Such higher doses of lytic delivery could increase the risk of bleeding.

[0006] Mechanical thrombectomy, in conjunction with systemic thrombolysis, is currently the standard of care for the treatment of acute ischemic stroke. There are two kinds of mechanical thrombectomy systems, coil retriever and stent retriever. The coil retrievers are composed of Nitinol shape-memory wire and delivered through a microcatheter across the target clot. As the device is extruded from delivery catheter, it immediately reassumes its native coil form. The neurointerventionalist deploys the loops of the coil through the clot to engage the thrombus, and then pulls both coil and clot back into the catheter, like pulling a cork from a wine bottle. The stent retrievers are selfexpanding stents that are deployed in the occluded vessel within the thrombus, engaging it and entangling it within the stent struts. The stent and thrombus are then withdrawn back into the delivery catheter.

[0007] With the capability of restoring flow in a single session, stent retriever removes a higher percentage of clot than the manual aspiration methods and can restore flow in a significantly less time than the lytic treatment alone. Despite their superiority in improving clinical outcomes in patients with acute ischemic strokes, however, stent retrievers are not without complications. Recent study has found that these devices could cause vascular damage that extends into the medial layer. Another common disadvantage of stent retriever is that stent retrieval necessarily induces clot fragmentation, which may result in distal embolization and occlusion of previously uninvolved territory. Thus, rooms for improvement remains.SUMMARY

[0008] One aspect of the present teachings provides an embolic capture device with visualization design. In various embodiments, an embolic capture device has a radially expanded deployed configuration and a radially collapsed delivery configuration. In itsradially expanded deployed configuration, the embolic capture device comprises a device body with a cylindrical shaped distal portion, and a wedge shaped proximal portion. The embolic capture device further includes an axial lumen with a distal opening, a proximal opening. A radiopaque proximal marker incorporates the entire perimeter of the proximal opening of the device body, forming a proximal marker ring. A first group of radiopaque markers attaches to the tubular surface of the distal portion of the device body. When viewed under a first view orientation, the first group of radiopaque markers is seen in a generally straight line angled to a longitudinal axis of the device body. And when viewed under a second view orientation, which is 90° axial rotation around the longitudinal axis of the device body from the first view orientation, the first group of radiopaque markers is seen as vertices of a two-dimensional shape. The embolic capture device further incorporates a second group of radiopaque markers also attaching to the tubular surface of the distal portion of the device body. When viewed under the first view orientation, the second group of radiopaque markers is seen as vertices of a two-dimensional shape, and under the second view orientation, the second group of radiopaque markers is seen in a generally straight line angled to the longitudinal axis of the device body.

[0009] Another aspect of the present teachings provides that, the first group of radiopaque markers includes at least three radiopaque markers. In another aspect, the second group of radiopaque markers includes at least three radiopaque markers.

[0010] Another aspect of the present teachings provides that the first group of radiopaque markers is positioned distal to the second group of three radiopaque markers. Additionally, when viewed in the first view orientation, the proximal marker ring is seen in a shape of an elliptical loop, and under the second view orientation, the proximal marker ring is seen as a generally straight line angled up distally.

[0011] Another aspect of the present teachings provides that the embolic capture device further comprises at least two radiopaque markers positioned at a distal end of the device body. Under the first view orientation, the two radiopaque markers at a distal end of the device body are radially opposite to each other across the longitudinal axis of the device body. And under the second view orientation, the two radiopaque markers positioned at a distal end of the device body are approximate to each other.

[0012] Another aspect of the present teachings provides that when the embolic capture device is in its collapsed delivery configuration, the proximal marker ring, the first group of the first group of the three radiopaque markers, and the second group of the three radiopaque markers all forms a generally straight line.

[0013] One aspect of the present teachings provides an embolic capture device a device body and radiopaque markers for visualization purpose. The device body has a cylindrical shaped distal portion and a wedge shaped proximal portion. The device body also includes an axial lumen with a distal opening, a proximal opening and a plurality of cell opening along a luminal surface. A radiopaque proximal marker incorporates the entire perimeter of the proximal opening of the device body, forming a proximal marker ring. At least two groups of radiopaque markers attaches to a tubular surface of the cylindrical shaped distal portion of the device body. Under a first view orientation, one of the at least two groups of radiopaque markers is seen in a generally straight line angled to a longitudinal axis of the device body, and the other one of the at least two groups of radiopaque markers is seen as vertices of a two-dimensional shape.

[0014] Another aspect of the present teachings provides that when the device body engages a blood clot, under the first view orientation, at least one distance between two vertices of the two-dimensional shape formed by one of the at least two groups of radiopaque markers changes comparing that of a device which is fully expanded radially and without any radial constrained.

[0015] One aspect of the present teaching provides a method of determining a state of engagement of the embolic capture device with the thrombus by assessing the shape and size of the two-dimensional shape formed by one of the at least two groups of radiopaque markers.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Fig. l is a perspective view of an embolic capture device in accordance with the present teachings.

[0017] Figs. 2A-2B are perspective views of an exemplary embolic capture device with radiopaque markers designed for visualization purpose in accordance with the present teachings.

[0018] Figs. 3A-3C are perspective views of an exemplary embolic capture device with radiopaque markers engaging blood clot in accordance with the present teachings.

[0019] Figs. 4A-4B are perspective views of an exemplary embolic capture device with radiopaque markers designed for visualization purpose in accordance with the present teachings.

[0020] Fig. 5 is a perspective view of a radiopaque marker engaging to an embolic capture device in accordance with the present teachings.DETAILED DESCRIPTION

[0021] In one aspect, 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.

[0022] In one aspect, the present teachings provide embolic capture device incorporated with visualization markers that allows 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 embolic capture device which allows a clinician easily to identify the orientation of the device within under x-ray, and accurately assess the device engagement with the emboli. In some embodiments, the embolic capture device of the present teachings is used to remove blood clots from vessels in the body. In some embodiments, the vessels are veins. In some embodiments, the system is used to treat, in veins, deep vein thrombosis (DVT), and in arteries, pulmonary embolism (PE), ST-elevated myocardial infarction (STEMI) and ischemic stroke. In some embodiments, the systems can also quickly clear dialysis arteriovenous grafts, which are prone to thrombus formation. According to some embodiments, when the catheter-basedemboli removal system of the present teachings is deployed into a blood vessel, the emboli removal device is expanded and moved proximally along the vessel so that the embolus engages the emboli removal device.

[0023] As used herein, the terms “radially outward” and “radially away” means any direction which is 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 that is attached or otherwise operatively coupled to the cylinder that is oriented at an angle greater than 0° relative to the central longitudinal axis of the cylinder.

[0024] As used herein, the term “lumen” means a canal, duct, 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.

[0025] 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.

[0026] As used herein the term “emboli” used herein can be clot, thrombus or the like, and these terms may be used interchangeably.

[0027] As explained in further detail below, various embodiments of the present teachings provide medical devices / system for removing blood clots from a vessel in the body. In some embodiments, the medical devices / system according to the present teachings may include an embolic capture device configured to capture the clot. In some embodiments, the embolic capture device according to the present teachings may be extended into an elongated profile for percutaneous delivery, resume to a radially expanded deployment profile for capturing the clot, and be extended into a second elongated profile to retrieve the clot. 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.

[0028] In another aspect, the present teachings disclose an embolic capture device for intracranial use. According to some embodiments, the embolic capture device has a general profile of a stent that 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 embolic capture device 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.

[0029] 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.

[0030] Fig. 1 shows an embodiment of the embolic capture device (10) of the present teachings in its pre-engineered deployed configuration. As illustrated in Fig. 1, the medical device can comprise a vascular device or embolic capture device (10) and a delivery wire (8). The distal end of the delivery wire (8) joins a proximal end (16) of the embolic capture device (10).

[0031] Further referring to Fig. 1, although not shown, the embolic capture device (10) is configured to be delivered through a microcatheter (not shown). During this delivery process, the distal end of a delivery wire (8) joins to the proximal end (16) of the embolic capture device (10). The embolic capture device (10) collapses radially and extends longitudinally. The proximal end (not shown) of the delivery wire (8) is controlled by a clinician. By manipulating the delivery wire (8), the embolic capture device (10) can be pushed distally through a microcatheter. Once the embolic capture device (10) reaches treatment location, the embolic capture device (10) is pushed outside the distal end of the microcatheter either by holding the delivery wire (8) steady while retracting the microcatheter proximally; or by holding the microcatheter steady while pushing the delivery wire (8) distally. Upon free of the constraint by the microcatheter,the embolic capture device (10) expands radially. As the proximal end (16) of the embolic capture device (10) continues joining the delivery wire (8), and once the embolic capture device (10) engages a blood clot, a clinician can pull the delivery wire (8) proximally such that the embolic capture device (10) can be retracted proximally back into the larger catheter (not shown) along with the blood clot it captured as needed.

[0032] Continuing referring to Fig. 1, the embolic capture device (10) is shown in its pre-engineered deployed configuration, where the device is fully expanded radially without any radial constrain, such as by a blood clot. In this configuration, embolic capture device (10) has a stent like cylindrical shaped distal portions (12), and a wedge shaped proximal portion (14) with the cylindrical surface area gradually reduces toward the proximal end (16) of the proximal portion of the embolic capture device (10). As shown, the embolic capture device (10) has an axial lumen, a distal opening (18), and a proximal opening (20), and the device (10) has a plurality of cell openings along the luminal surfaces.

[0033] According to one embodiment of the present teachings, and as shown in Fig. 1, the proximal opening (20) and the distal opening (18) of the embolic capture device (10) are not parallel. In one embodiment, the distal opening (18) of the embolic capture device (10) is generally perpendicular to a longitudinal axis (30) of the embolic capture device (10), while the proximal opening (20) of the embolic capture device (10) forms a non-perpendicular angle with the longitudinal axis (30) of the embolic capture device.

[0034] Continuing referring to Fig. 1, according to one embodiment of the present teachings, the proximal portion (14) of the embolic capture device (10) is in the shape of a cylindrical wedge, with the proximal opening (20) being in the shape of an ellipse. In one embodiment, the distal end of (22) the proximal opening (20) is at one radial side of the longitudinal axis (30) of the embolic capture device (10), and the proximal end (24) of the proximal opening (20) is at the opposite radial side of the longitudinal axis (30) of the embolic capture device (10). In another embodiment, the proximal end of the proximal opening (20) is also the proximal end of the embolic capture device (10).

[0035] In one aspect of the present teachings, the embolic capture device (10) has an elongated delivery profile and an expanded deployed profile. In its delivery profile, theembolic capture device (10) has an elongated, radially collapsed configuration suitable for delivery via a microcatheter. In its deployed profile, the embolic capture device (10) expands radially and substantially engages the blood vessel within which it is deployed. In one embodiment, when free of any radial constraint, such as, outside of the microcatheter and without the engagement of the blood clot, the embolic capture device (10) has a pre-engineered radially expanded configuration. Said embolic capture device (10) also has a partial radially expanded configuration when it engages a blood clot. In one embodiment, such partial radially expanded profile is radially smaller than the preengineered radially expanded profile due to radial constraint imposed by the blood clot.

[0036] In some embodiments, the embolic capture device (10) has a cell structure which allows the device to collapse during the delivery and to expand upon the deployment. As shown in Fig. 1, the embolic capture device (10) has generally closed cells of uniform size throughout its entire length. One skilled in the art would acknowledge that exemplary embolic capture devices could have cells of various shapes and sizes at various portions of the device, and the devices could have open cells and close cells strategically placed at various portions of the device. Additionally, the device could have an opening placed along its length, for example, a helical opening along the cylindrical surface of the device.

[0037] According to one embodiment of the present teachings, the embolic capture device expands upon deployment in vivo. In one embodiment of the present teachings, upon deployment, the embolic capture device expands radially due to the elastic nature of the material. In another embodiment, such radial expansion is achieved by the preengineered thermal shape memory of the device material. In yet another embodiment, such radial expansion is achieved manually via an inflating balloon. In some embodiments, the embolic capture device (10) is made of stainless steel, nitinol, Titanium, Elgiloy, Vitalium, Mobilium, Ticonium, Platinore, Stellite, Tantalum, Platinum, Hastelloy, CoCrNi alloys (e.g., trade name Phynox), MP35N, or CoCrMo alloys, any other metallic alloys, or a mixture thereof.

[0038] According to one embodiment, when the embolic capture device (10) of the present teachings is used to retrieve emboli, a positioning wire is first threaded throughthe blood vessel across a blood clot. A microcatheter then threads over the positioning wire and has its distal end positioned distally to the clot. The positioning wire is then removed, followed by a delivery wire (8) joined to a proximal end (16) of an elongated device extending through the lumen of the microcatheter. While holding the delivery wire (8) and the elongated device steady, a clinician withdraws the microcatheter proximally to uncover the embolic capture device (10). Once outside of the microcatheter, the embolic capture device (10) radially expands to stretch the wall of the artery so blood can flow. In one embodiment, the embolic capture device (10) is deployed across the clot. In some embodiments, to retrieve the clot, the clinician pulls the delivery wire (8) proximally, the embolic capture device (10) is pulled proximally back, carrying the blood clot back into a larger catheter, guide catheter, or distal access catheter (DAC).

[0039] Figs. 2A-2B illustrate one exemplary embodiment of the embolic capture device (10) incorporating a plurality of radiopaque markers. Figs. 4A-4B illustrate another exemplary embodiment of the embolic capture device (10) also incorporating a plurality of radiopaque markers. 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 sewed, adhered, swaged riveted, otherwise placed, and secured in or on the device. Fig. 5 illustrates one exemplary embodiment where the radiopaque marker is in a coil configuration wrapped around, and secure to a portion of the device.

[0040] 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.

[0041] In one embodiment of the present teaching, as shown in Figs. 2A-2B, a proximal marker band wraps the entire perimeter of the proximal opening (20) of the embolic capture device (10), forming a proximal marker ring (40). When visualizedunder x-ray, the proximal marker ring (40) is a loop under one view orientation as shown in Fig. 2A, and a generally straight line angled upward distally to the longitudinal axis (30) of the embolic capture device (10) as shown in Fig. 2B, when rotating 90° as indicated by arrow A on Fig. 2A.

[0042] Figs. 2A-2B show two-dimensional side view of embolic capture device (10) where the distal portion (12) of the embolic capture device (10) is in a generally rectangular shape. When the embolic capture device (10) in the view orientation of Fig. 2A rotates 90° around its longitudinal axis (30) in the direction of arrow A in Fig. 2A, it arrives the view orientation of Fig. 2B. One skilled in the art should understand that after rotating 90° around its longitudinal axis (30), the top and bottom rectangular edges of the embolic capture device (10) in the view orientation of Fig. 2A, now aligns with the longitudinal axis (30) as shown in Fig. 2B. Similarly the top and bottom rectangular edges of the embolic capture device (10) in the view orientation of Fig. 2B, aligns with the longitudinal axis (30) as shown in Fig. 2 A.

[0043] The present exemplary embodiment also teaches a design where a group of radiopaque markers, under one view orientation, is seen as three vertices of a triangle, while under another view orientation, the same group of radiopaque markers is seen as a generally straight line. As shown in the Figs. 2A-2B, the device includes at least two groups of radiopaque markers (42a-42c, 44a-44c) attaching to the tubular surface of the distal portion (12) of the embolic capture device (10) for visualization purpose, a proximal group (42a-42c) and a distal group (44a-44c) of radiopaque markers. As shown in the figures, each group of markers (42a-42c, 44a-44c) consists of three individual radiopaque markers strategically attached to various longitudinal and radial locations across the tubular surface of the distal portion (12) of the embolic capture device (10), such that in certain view orientation, one group of the three radiopaque markers forms a triangle shape and the other group of three radiopaque markers forms a generally straight line. Specially, at the two-dimensional view orientation shown in the Fig. 2A, the proximal group of three radiopaque markers (42a-42c) can be seen forming a generally straight line angled to the longitudinal axis (30) of the embolic capture device (10). Under the same two-dimensional view orientation shown in the Fig. 2A, the distal group of three radiopaque markers (44a-44c) forms a triangle.

[0044] The same embolic capture device (10) when rotating 90° as indicated by arrow A on Fig. 2A, the same embolic capture device (10) can be observed at the view orientation shown in the Fig. 2B. Specially, at the two-dimensional view orientation shown in the Fig. 2B, the proximal group of three radiopaque markers (42a-42c) forms a triangle. Under the same two-dimensional view orientation shown in the Fig. 2B, and the distal group of three markers (44a-44c) are in a generally straight line angled from the longitudinal axis (30) of the embolic capture device (10).

[0045] Although two three-marker groups (42a-42c, 44a-44c) are illustrated and explained in details above, one skilled in the art should understand that more than two three-marker groups could be incorporated into the distal portion of the embolic capture device, for example, three three-marker groups could be incorporated into the distal portion of the embolic capture device, or four three-marker groups could be incorporated in the distal portion of the embolic capture device. Thus, the specific number of the marker groups should not be limited by the examples of the present teachings. Additionally, the placement configuration of these marker groups should also not be limited by the examples of the present teaching. For example, under one view orientation, the distal portion of the embolic capture device could have a proximal group of radiopaque markers in a triangle shape, followed by a middle group of radiopaque markers in a line shape, and then a distal group of radiopaque marks also in a triangle shape. In another example, under one view orientation, the distal portion of the embolic capture device could have a proximal group of radiopaque markers in a line shape, followed by a middle group of radiopaque markers in a triangle shape, and then a distal group of radiopaque marks also in a line shape.

[0046] Moreover, although a three-marker group that is oriented in the shape of a triangle in one view orientation, and a generally straight line in another view orientation has been illustrated and described above, one skilled in the art should understand that groups of any numbers radiopaque markers could all serve the purpose of the present teachings. For example, a four-marker group could be incorporated for the purpose of the present teachings. Said group of markers could be oriented in a shape of a quadrilateral under one view orientation, and in a shape of a different shape, such as a generally straight line in another view orientation. Thus, the numbers of markers within one group should not be viewed as limiting to the exemplary embodiment described above.Additionally, the shapes under different view orientation of the marker groups should also not be viewed as limiting to the exemplary embodiment described above, e.g., two- dimensional in one view, and a generally straight line in another view. For example, the device could have a four marker group, which under one view orientation seen as a square, and under another view orientation seen as a parallelogram.

[0047] Continuing referring to Figs. 2A-2B, the embolic capture device (10) further includes at least two distal markers (46a-46b). The distal markers (46a-46b) are placed at the distal end (18) of the embolic capture device (10), for example, at the distal apex of the cell as shown in Figs. 2A-2B. According to one embodiment of the present teachings, in the view orientation shown in Fig. 2A, the two distal markers (46a-46b) are approximate to each other near the longitudinal axis (30) of the embolic capture device (10). In another view orientation shown in Fig. 2B, where the same embolic capture device (10) rotates 90° around the longitudinal axis (30) as indicated by arrow A on Fig. 2A, the two distal markers (46a-46b) are viewed radially opposite to each other as near the top and bottom rectangular edges as shown in Fig. 2B.

[0048] According to one embodiment of the present teachings, proximal marker ring (40), two groups of three markers (42a-42c, 44a-44c), and two distal markers (46a-46b) together can be used for visualization purpose, during the device delivery, deployment, blood clot capture and etc. For example, under x-ray, the embolic capture device (10) is visualized in the view orientation shown in Fig. 2A, the proximal marker ring (40) is a generally straight line angled to the longitudinal axis (30) of the embolic capture device (10), the proximal group of the markers (42a-42c) align in a generally straight line also angled to the longitudinal axis (30) of the embolic capture device (10), the distal group of the markers (44a-44c) is seen as a triangle, and the two distal markers (46a-46b) approximate to each other. As the embolic capture device (10) rotates 90° as indicated by arrow A on the Fig. 2A, the embolic capture device (10) is then viewed in the view orientation as shown in Fig. 2B, where the proximal marker ring (40) is an elliptical loop, the proximal group of the markers (42a-42c) forms a triangle, the distal group of the markers (44a-44c) align in a generally straight line angled to the longitudinal axis (30) of the embolic capture device (10), and the two distal markers (46a-46b) are opposite to each other and near the top and bottom rectangular edges of the embolic capture device (10).

[0049] According to one embodiment of the present teachings, the radiopaque markers are used for clinicians to assess the deployment and clot capturing of the embolic capture device (10). According to one embodiment of the present teachings, during a delivery, the embolic capture device (10) collapses radially, sometimes also lengthens longitudinally with all radiopaque markers packed near the longitudinal axis (30) of the embolic capture device (10), so that when visualized under x-ray, both the proximal marker ring (40), the proximal group of markers (42a-42c), the distal group of markers (44a-44c) are seen in a generally straight lines and near the longitudinal axis (30), and the two distal markers (46a-46b) are also approximate to each other and near the longitudinal axis (30). During a deployment, when free of radial constraint imposed by the microcatheter, the embolic capture device (10) expands radially, and sometimes also shortens longitudinally with all radiopaque markers moves away from one another.

[0050] According to one embodiment of the present teachings, radiopaque markers can be used for clinicians to assess blood clot engagement at the treatment site. As shown in Fig. 3A, as the deployed distal portion (12) of the embolic capture device (10) engages a blood clot (4) inside a vasculature (6), the radial expansion of the distal portion (12) of the embolic capture device (10) is then limited by the blood clot (4) and the vasculature (6). In another word, the distal portion (12) of the embolic capture device (10) cannot fully expand to its pre-engineered configuration due to the existence of the blood clot (4), or at least a portion of the embolic capture device (10) that engages the blood clot (4) cannot fully expands into its pre-engineered radially expanded configuration. Hence, when viewed at a certain orientation under x-ray, as shown in Fig. 3 A, by comparing the overall the size and / or shape of one or both groups of three radiopaque markers (42a- 42c), a clinician can determine where the blood clot is captured on the device, along with other information such as the size and / or strength of the blood clot. For example, the distance (52a-52c) between the three radiopaque markers (42a-42b) under this two- dimensional view orientation, can be measured and compared with corresponding preengineering distance between those radiopaque markers (42a-42c) when fully expanded and free of radial constraint. In an alternative example, as shown in Fig. 3B, the projected height (54) from one radiopaque marker (42a) to the line formed by the other two radiopaque markers (42b-42c) can be measured and compared with corresponding preengineered fully expanded and free of radial constraint parameter. Similarly, the twodistal markers (46a-46b) can also be used in the blood clot engagement assessment. As shown in Fig. 3C, under a certain view orientation, a clinician can compare the distance (56) between two distal markers (46a-46b) with its pre-engineering distance when fully expanded and free of radial constraint to determine whether the distal end (18) of the embolic capture device (10) has engaged a blood clot (4).

[0051] Figs. 4A-4B illustrates another exemplary embodiment of the present teaching, where a proximal radiopaque marker (60) is incorporate at a location on the wedge shaped proximal portion (14) of the embolic capture device (70). Similar to Figs. 2A-2B, Figs. 4A-4B shows the exemplary embodiment of the embolic capture device (70) in its fully deployed and without constrained configuration. In the exemplary embodiment shown in Fig. 4A, a proximal radiopaque marker (60) is placed approximately at the longitudinal center of the cylindrical surface of the wedge shaped proximal portion (14), and generally radially opposite to the center of the proximal opening (72). Similarly to the exemplary embodiment shown in Figs. 2A-2B, the embolic capture device (70) also incorporates a proximal group of three radiopaque markers (62a- 62c) and a distal group of three radiopaque markers (64a-64c), with the three individual radiopaque markers of each group (62a-62c, 64a-64c) strategically attach to various longitudinal and radial locations across the tubular surface of the distal portion (12) of the embolic capture device (70), such that in certain view orientation, the group of three markers forms a two-dimensional shape, such as a triangle, and in another view orientation the same group of the three marks forms a generally straight line.

[0052] As shown in Fig. 4A, according to the exemplary embodiment, at the two- dimensional view orientation shown in the figure, the proximal opening (72) of the embolic capture device (70) in a generally angled line profile, the proximal group of three radiopaque markers (62a-62c) forms a triangle shape with two radiopaque marks (62a, 62c) aligning with the longitudinal axis (80) of the embolic capture device (70) and the third radiopaque marker (62b) at the bottom rectangular edge of the embolic capture device (70); the distal group of three radiopaque markers (64a-64c) aligns in a generally straight line angled to the longitudinal axis (80) of the embolic capture device (70) with one radiopaque marker (64c) aligning the top rectangular edge of the embolic capture device (70), one radiopaque marker (64b) aligning with the longitudinal axis (80) of the embolic capture device (70) and the third radiopaque marker (64a) aligning the bottomrectangular edge of the embolic capture device (70). At this two-dimensional view orientation, and proximal radiopaque marker (60) aligns with one radiopaque marker (62b) in the proximal group and one radiopaque marker (64a) in the distal group, showing the bottom rectangular edge of the embolic capture device (70).

[0053] The same embolic capture device (70) when rotating 90° as indicated by arrow B on Fig. 4A, the embolic capture device (70) can be observed at the view orientation shown in the Fig. 4B, where the proximal opening (72) faces upward, the three radiopaque markers in the proximal group (62a-62c) align in a generally straight line angled to the longitudinal axis (80) of the embolic capture device (70) with one radiopaque marker (62c) aligning the top rectangular edge of the embolic capture device (70), one radiopaque marker (62b) aligning with the longitudinal axis (80) of the embolic capture device (70) and the third radiopaque marker (62a) aligning the bottom rectangular edge of the embolic capture device (70); and the three radiopaque markers in the distal group (64a-64c) can be seen forming a triangle shape with two radiopaque marks (64a, 64c) aligning with the longitudinal axis (80) of the embolic capture device (70) and the third radiopaque marker (64b) at the top rectangular edge of the embolic capture device (70). At this two-dimensional view orientation, and proximal radiopaque marker (60) aligns with one radiopaque marker (62b) in the proximal group and two radiopaque marker (64a and 64c) in the distal group, showing the longitudinal axis (80) of the device (70).

[0054] Continue referring to Figs. 4A-4B, the embolic capture device (70) further includes at least two distal radiopaque markers (66a-66b). The distal radiopaque markers (66a-66b) are placed at the distal end (78) of the embolic capture device (70), for example, at the distal apex of the cell as shown in Figs. 4A-4B. According to one embodiment of the present teachings, in the view orientation shown in Fig. 4A, the two distal radiopaque markers (66a-66b) are radially opposite to each other across the longitudinal axis (80) of the embolic capture device (70). In another view orientation shown in Fig. 4B, where the same embolic capture device (70) rotates 90° around the longitudinal axis (80) as indicated by arrow B on Fig. 4A, the two distal radiopaque markers (66a-66b) are viewed approximate to each other and near the longitudinal axis (80) as shown in Fig. 4B.

[0055] Similarly to what has been described above, although two three-marker groups (62a-62c, 64a-64c) are illustrated in Figs. 4A-4B and explained in details above, one skilled in the art should understand that more than two three-marker groups could be incorporated into the device. Thus, the specific number of the marker groups should not be limited by the examples of the present teachings. Additionally, the placement configuration of these marker groups should also not be limited by the examples of the present teaching. In addition, although the exemplary embodiment shown in Figs. 4A-4B shows that the embolic capture device(70) has one proximal radiopaque marker (60) and two distal radiopaque markers (66a, 66b) are incorporated to the embolic capture device (70) along with the proximal group of three radiopaque markers (62a-62c) and the distal group of three radiopaque markers (64a-64c), one skilled in the art should understand that embolic capture device (70) could have only the proximal group of three radiopaque markers (62a-62c) and the distal group of three radiopaque markers (64a-64c), without one or both of the one proximal radiopaque marker (60) and two distal radiopaque markers (66a, 66b).

[0056] Referring back to Fig. 1, the embolic capture device (10) has a plurality of open mesh-like structure throughout the entire length of the embolic capture device (10) such that the device does not impede the blood flow. In some embodiments of the present teachings, the embolic capture device (10) is fabricated by laser-cutting or acid-etching a pattern into a preformed tube, then shape-setting the device to the intended radially expanded configuration. In such embodiments, the mesh is formed by slotting a hollow tube, for example, with a machining laser, water drill, or other methods, and expanding the slotted hallow tube to form an open structure. Alternatively, the device may also be formed with a woven, knitted, or braided tubular metallic fabrics made out of metallic strands. The term “strand” used herein can be wires, cords, fibers, yarns, filaments, cables, threads, or the like, and these terms may be used interchangeably. According to one embodiment, the wire used to form the device has a general diameter from about 0.02 mm to about 1 mm. In another embodiment of the present teachings, the mesh is formed from wires that are pre-bent into the desired shape and then bonded together to connect elements either by welding or adhesively 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. In another embodiment, the device is made by rolling up a planar two-dimensional structure to form into a tubular construct with a slit extending along the tubular surface. Such slit could be of a straight line parallel to the longitudinal axis of the device, or could be of a helically shape extending long the tubular surface of the device.

[0057] In some embodiments, the device in whole or in certain 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, Platinum, 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 a mammalian tissue, or other bioengineered materials, bioabsorbable polymers such as polyactic acid, polyglycolic acid, polycaprolactone, or other natural materials (e.g., collagen), or combinations of these materials.

[0058] 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 is for the purpose of description and should not be regarded as limiting.

[0059] 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 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 ofconflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Claims

CLAIMS1. An embolic capture device having a radially expanded deployed configuration and a radially collapsed delivery configuration, wherein the embolic capture device in its radially expanded deployed configuration comprising: a device body with a cylindrical shaped distal portion and a wedge shaped proximal portion, wherein the device body includes an axial lumen with a longitudinal axis and a tubular surface, a distal opening, a proximal opening, and a plurality of cell opening along a luminal surface, a first group of three radiopaque markers attaching to the tubular surface of the cylindrical shaped distal portion of the device body, wherein under a first view orientation, the three radiopaque markers of the first group align in a generally straight line angled to the longitudinal axis of the device body; and under a second view orientation, the three radiopaque markers of the first group form a triangle; a second group of three radiopaque markers attaching to the tubular surface of the cylindrical shaped distal portion of the device body, wherein under the first view orientation, the three radiopaque markers of the second group form a triangle; and under the second view orientation, the three radiopaque markers of the second group align in a generally straight line angled to the longitudinal axis of the device body; and wherein the first view orientation and the second view orientation are 90 degrees rotation from around the longitudinal axis of the device body.

2. The embolic capture device of claim 1, wherein the device body further comprises a proximal radiopaque marker ring incorporating an entire perimeter of the proximal opening.

3. The embolic capture device of claim 2, wherein under the first view orientation, the proximal radiopaque marker ring is a shape of an elliptical loop; and under the second view orientation, the proximal radiopaque marker ring is a generally straight line angled to the longitudinal axis of the device body.

4. The embolic capture device of claim 1, wherein the device body further comprises at least two distal radiopaque markers positioned at a distal end of the device body.

5. The embolic capture device of claim 4, wherein under the first view orientation, the two distal radiopaque markers are radially opposite to each other across the longitudinal axis of the device body; and under the second view orientation, the two radiopaque markers are next to each other.

6. The embolic capture device of claim 1, wherein the device body further comprises a proximal radiopaque marker attaching to a tubular surface of the wedge shaped proximal portion, and wherein the proximal radiopaque marker is opposite of a center of the proximal opening across the longitudinal axis of the device body.

7. The embolic capture device of claim 6, wherein under the first view orientation, the proximal radiopaque marker aligns with the longitudinal axis of the device; and under the second view orientation, the proximal radiopaque marker is near a tubular edge of the device.

8. The embolic capture device of claim 1, wherein the embolic capture device further comprises at least one more group of three radiopaque markers.

9. The embolic capture device of claim 1, wherein in the radially collapsed delivery configuration, the first group of three radiopaque markers and the second group of three radiopaque markers all forms a generally straight line.

10. An embolic capture device having a radially expanded deployed configuration and a radially collapsed delivery configuration, wherein the embolic capture device in its radially expanded deployed configuration comprising: a device body with a cylindrical shaped distal portion and a wedge shaped proximal portion, wherein the device body includes an axial lumen with a longitudinal axis and a tubular surface, a distal opening, a proximal opening, and a plurality of cell opening along a luminal surface, a first group of three radiopaque markers attaching to the tubular surface of the cylindrical shaped distal portion of the device body, wherein under a first view orientation, the three radiopaque markers of the first group align in a generally straight line angled to the longitudinal axis of the device body with two radiopaque markers near two opposite tubular edges of the device body and one radiopaque marker near thelongitudinal axis of the device body; and under a second view orientation, the three radiopaque markers of the first group form a triangle with one radiopaque marker near a tubular edge of the device body and the other two radiopaque markers near the longitudinal axis of the device body; wherein the first view orientation and the second view orientation are 90 degrees rotation from around the longitudinal axis of the device body.

11. The embolic capture device of claim 10, wherein the device body further comprises a second group of three radiopaque markers attaching to a tubular surface of the cylindrical shaped distal portion of the device body, wherein under a first view orientation, the three radiopaque markers of the second group form a triangle with one radiopaque marker near a tubular edge of the device body and two radiopaque markers near the longitudinal axis of the device body; and under a second view orientation, the three radiopaque markers of the second group align in a generally straight line angled to a longitudinal axis of the device body with two radiopaque markers near two opposite tubular edges of the device body, one radiopaque marker near the longitudinal axis of the device body.

12. The embolic capture device of claim 11, wherein the device body further comprises at least one more group of three radiopaque markers.

13. The embolic capture device of claim 11, wherein the device body further comprises a proximal radiopaque marker attaching to a tubular surface of the wedge shaped proximal portion, and wherein the proximal radiopaque marker is opposite of a center of the proximal opening across the longitudinal axis of the device body.

14. The embolic capture device of claim 13, wherein under the first view orientation, the proximal radiopaque marker is near the longitudinal axis of the device; and under the second view orientation, the proximal radiopaque marker is near the tubular edge of the device.

15. The embolic capture device of claim 14, wherein under the first view orientation, the proximal radiopaque marker aligns with one radiopaque marker of the first group of three radiopaque markers and with two radiopaque markers of the second group of three radiopaque markers, and under the second view orientation, the proximal radiopaquemarker aligns with one radiopaque marker of the first group of three radiopaque markers and with one radiopaque marker of the second group of three radiopaque markers.

16. The embolic capture device of claim 10, wherein the device body further comprises at least two distal radiopaque markers positioned at a distal end of the device body.

17. The embolic capture device of claim 16, wherein under the first view orientation, the two radiopaque markers are next to each other, and under the second view orientation, the two radiopaque markers are radially opposite to each other across the longitudinal axis of the device body.

18. A method of engaging a thrombus, the method comprising: advancing an embolic capture device to a location radially adjacent to a thrombus in a blood vessel, and the embolic capture device comprising a device body with a cylindrical shaped distal portion and a wedge shaped proximal portion, at least one group of three radiopaque markers attaching to a tubular surface of the cylindrical shaped distal portion of the device body; wherein under a first view orientation, the three radiopaque markers of the at least one group form a triangle; and under a second view orientation, the three radiopaque markers of the at least one group align in a generally straight line angled to a longitudinal axis of the device body; expanding the embolic capture device into the thrombus, assessing the size and shape of the triangle formed by the three radiopaque markers of the at least one group under the first view orientations; determining a state of engagement of the embolic capture device with the thrombus.

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