FIELD OF INVENTION

[001] The present invention relates to a retrieval device. More specifically, the present invention relates to a retrieval device for retrieving clots.

BACKGROUND

[002] Occlusion of blood capillaries can be caused due to migration of thrombus along with blood circulation (i.e. embolus). The occlusion disrupts blood flow which makes the brain tissue that lays distal to the blood clot deficient in oxygen supply and nutrients. It may further result in tissues death, and the patient may show symptoms of stroke.

[003] Present treatment options available include self-expanding retrievable stents for revascularization of blood vessels. The stent is expanded across the thrombus which is then entangled in the mesh of the stent and thereafter, removed by a physician.

[004] However, these devices are not very effective at treating hard thrombus. In fact, the thrombus is often compressed against the vessel wall by the stent which temporarily opens the vessel. While retrieving the device, the clot may break up into several pieces which may emboli the vessels further along.

[005] One such device is disclosed in US patent publication, US8357179B2. The device disclosed in the said publication includes a closed cylindrical structure having symmetric cells disposed from one end to the other end of the device. The device disclosed in the publication is unable to expand through the clot thus, leaving the clot mass behind at the treatment site. Also, the device does not entangle/engulf the clot in the mesh sufficiently.

[006] Therefore, there arises a requirement of a clot retrieval device which overcomes the aforementioned challenges associated with the conventional retrieval devices.

SUMMARY

[007] The present invention relates to a clot retrieval device having an end region and a working region. The end region further includes a plurality of tangential struts and curved struts. Each tangential strut extends from an edge of a respective curved strut. The working region is placed adjacent to the end region. The working region includes a plurality of small sized cells and large-sized cells. The small-sized cells and large-sized cells form a reticulated structure. The large-sized cell includes an area multiple times than the small-sized cell. The rows of small-sized cells are placed at an offset with each other creating a tread like pattern.

[008] The foregoing features and other features as well as the advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF DRAWINGS

[009] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.

[0010] Fig. 1 depicts a clot retrieval device 1 in accordance with an embodiment of the present invention. [0011] Fig. 2 depicts an end region 100 of the device 1 in accordance with an embodiment of the present invention.

[0012] Fig. 2a depicts a rectangular strut of the end region 100 of the device 1 in accordance with an embodiment of the present invention.

[0013] Fig. 3 depicts a working region 200 of the device 1 in accordance with an embodiment of the present invention.

[0014] Fig. 3a depicts a square strut of the end region 100 of the device 1 in accordance with an embodiment of the present invention.

[0015] Fig. 4a depicts a small-sized cell 220 of the device 1 in accordance with an embodiment of the present invention. [0016] Fig. 4al depicts a three-dimensional illustration a continuous intricate strut structure of the device 1 in accordance with an embodiment of the present invention.

[0017] Fig. 4a2 depicts the structure of the intricate struts retrieved within a micro-catheter 400 in accordance with an embodiment of the present invention. [0018] Fig. 4b depicts a large-sized cell 230a of the device 1 in accordance with an embodiment of the present invention.

[0019] Fig. 5 depicts a longitudinal cell connecting link 230a and a lateral row connecting link 230b in accordance with an embodiment of the present invention. [0020] Fig. 6a depicts a tread pattern due to a placement of cells 220 in accordance with an embodiment of the present invention.

[0021] Fig. 6b depicts a stratified pattern due to the placement of rows of cells 220 in accordance with an embodiment of the present invention.

[0022] Fig. 7 depicts an alternate embodiment of the device 1 in accordance with an embodiment of the present invention.

[0023] Fig. 8a depicts a side view of the device 1 when inside a vessel having diameter same as the device 1 diameter in accordance with an embodiment of the present invention.

[0024] Fig. 8b and 8c depicts a side view of the device 1 when inside a vessel having diameter smaller than the device 1 diameter in accordance with an embodiment of the present invention.

[0025] Fig. 9 depicts a crimped view of the device 1 in a micro-catheter 400 in accordance with an embodiment of the present invention.

[0026] Fig. 10 depicts a crimped view of the cells of the device 1 in a micro-catheter 400 in accordance with an embodiment of the present invention. [0027] Fig. 11a depicts the device 1 along with a delivery wire 300 and a micro-catheter 400 in accordance with an embodiment of the present invention.

[0028] Fig. lib depicts the delivery wire 300 in accordance with an embodiment of the present invention.

[0029] Fig. 12 depicts a device Ά' of the prior art. DETAILED DESCRIPTION OF THE DRAWINGS

[0030] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms "include" and "comprise", as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "coupled with" and "associated therewith", as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like; Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.

[0031] Reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "including," "comprising," "having," and variations thereof mean "including but not limited to" unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also refer to "one or more" unless expressly specified otherwise.

[0032] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.

[0033] Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.

[0034] In accordance with the present disclosure, a clot retrieval device is disclosed. The device of the present invention may be used to retrieve a clot/thrombus/embolus from neurovascular vessels like ICA, MCA, M1-M2 segment and/or other associated intracranial vessels. The present invention relates to a self-expandable device that includes a plurality of rows of cells forming a mesh like structure for better radial expansion, smooth transition or navigation of the device through neurovascular anatomy to the treatment site and better retrieval of the clot/thrombus from the vessel. The cells may be of different types including large-sized cells and small-sized cells for better removal of blood clots from intracranial vessels and/or carotid arteries.

[0035] The clot retrieval device of the present invention provides a way to improve the blood flow by retrieving the thrombus from the intracranial vessels of a patient who has suffered an ischemic stroke and have failed IV t-PA Plasminogen therapy. The device can penetrate through various types of clots including firm white clots due to its high radial strength. The radial strength of the device ranges from 6N/mm ² to 15N/mm ² . The device can retrieve clots having a diameter of more than 90 micron and a length between 1mm and 40mm or more. The device can retrieve blood clot from a vessel having a diameter in the range of 1mm to 6mm. The device can retrieve clots having a size in the range of 0.09mm to 376.8mm in a single pass. The device having a diameter ranging from 4mm to 6mm can have a crimped profile having a diameter ranging from 0.5mm to 0.9mm.

[0036] The clot retrieval device has low lateral bending stiffness for excellent track-ability and introduction through neurovascular tortuous vessels/anatomy due to low radius of canthus region and intricate strut structure.

[0037] Fig. 1 illustrates a three dimensional view of the clot retrieval device 1 of the present invention. The clot retrieval device is attached on a delivery wire and inserted in the human vasculature on a guide wire based delivery system. The device includes an open reticulated structure with different types of cells etched on a tube. The reticulated structure may be cylindrical or tubular. Different types of cells include large-sized cells, small-sized cells, etc. As an exemplary depiction in Fig. 1, a combination of large-sized and small-sized cells is illustrated that are encapsulated in the cylindrical reticulated structure on a tube to capture blood clot form the intracranial vessel. [0038] The device 1 includes a tube made of a self-expandable material which is designed to required configuration. The tube may be made of any self-expandable material including but not limited to nitinol, cobalt-chromium, etc. Other self-expandable materials used for manufacturing the tube apart from the examples stated may also be used. The tube may be laser cut, engraved or etched to obtain the required configuration. In an embodiment, the device 1 is laser cut on a nitinol tube.

[0039] The device 1 may have a diameter ranging from 1mm to 10mm, preferably from 2mm to 7mm. In an embodiment, the device 1 has a diameter of 4mm and can be used for the treatment of vessels having diameter in the range of 2mm to 4mm.

[0040] The device 1 may include at least one radiopaque marker 210. The radiopaque marker 210 may help a physician visualize/track the device 1 in vivo.

[0041] The device 1 may be parted into two regions longitudinally namely, an end region 100 and a working region 200. The end region 100 (shown in Fig. 2) is placed adjacent to the working region 200 (shown in Fig. 3). The end region 100 may include struts defined in a cross- sectional shape different from the shape defined by the struts in the working region. This arrangement of the two regions provides for better deployment, better expansion, and swift/smooth re-sheathing of the device within a micro-catheter 400.

[0042] For instance, the end region 100 may include at least one tangential strut 110 (shown in Fig. 2) extending from the edge of a respective curved strut 105. In an embodiment, the end region 100 has two tangential struts 110. Each tangential strut 110 may have a length ranging from 5mm to 15mm, preferably from 9mm to 13mm.

[0043] The tangential struts 110 may be placed at an angle b with respect to a longitudinal axis 'X'. The angle b between the tangential struts 110 and the longitudinal axis 'X' may range from 20" to 65\ preferably from 25 ^* to 3S . The tangential struts 110 may be placed at an angle T with respect to the curved struts 105. The angle T between the tangential struts 110 and the curved struts 105 may range from 15° to 30°, preferably from 23° to 28°. In an embodiment, angle b is different from angle T. In an alternate embodiment, angle b is same as angle T.

[0044] Having different angles b and T provides better navigation of the device 1 in tortuous anatomy and retrieval of the device 1 in the micro-catheter 400. Further, the said angles of the tangential struts 110 with respect to the longitudinal axis 'X' of the device 1 helps generation of the overlap during the interventional procedure if the vessel diameter is less compare to the device diameter. Also, these angles improvise in better retrieval or re-sheathing of the device in micro-catheter without any interruption.

[0045] In an embodiment, the tangential struts 110 have a rectangular cross-section (shown in Fig. 2a). This provides better strength and stiffness for easy transfer of a thrust force applied by a physician for the deployment of the device 1 without kinking, twisting or knotting.

[0046] In an embodiment, the curved struts 105 encircled by the tangential struts 110 are arranged in the shape of a drop. The dimensions of curved strut 105 ranges from 4mm to 6mm.

[0047] The strut of the end region 100 may have a thickness ranging from 40 micron to 100 micron, preferably from 55 micron to 85 micron. The struts of the end region 100 may have a width ranging from 60 micron to 140 micron, preferably from 80 micron to 120micron. The length of the end region 100 may be dependent on the diameter of the device 1 and may range from 5 mm to 20 mm, preferably from 8 mm to 15 mm. Further, as an example, the end region 100 may be tapered. Thus, the tangential struts 110 and curved struts 105 would be placed at an angle with respect to the longitudinal axis 'X'.

[0048] The working region 200 (cross-sectional view depicted in Fig. 3) may have a length ranging from 10mm to 60mm, preferably from 15mm to 45mm. The length of the working region 200 may depend upon the dimensional or physical properties of the clot.

[0049] The working region 200 may include a plurality of row of cells forming a mesh-like structure as depicted in Fig. 3. Each row may be formed by placing cells longitudinally adjacent to each other in the reticulated structure. In an exemplary depiction, the cells include small sized cells 220 and large-sized cells 225. The small-sized cells 220 (expanded view depicted in Fig. 4a) as well as large-sized cells 225 (expanded view depicted in Fig. 4b) may be arranged in a manner so as to form a mesh (or reticulated structure). For example, a row is formed by placing small-sized cells 220 adjacent to one another longitudinally. The small-sized cells 220 improvise strength to expand through a clot while the large-sized cells 225 engulf the blood clot and hold the blood clot while retrieval of the clot in the micro-catheter 400. The small-sized cells 220 also assist in better expansion of the device 1 through the clot by transferring appropriate radial force due to strut angle kept for better expansion. In an embodiment, the small-sized cells 220 are leaf-shaped while the large-sized cells are irregular-shaped.

[0050] The area of the small-sized cells 220 is smaller compared with the area of the large-sized cells 225. The small-sized cell 220 may have an area ranging from 2mm ² to 10mm ² , preferably from 4mm ² to 7mm ² . In an embodiment, area of the small-sized cells 220 is one-third the area of the large-sized cells 225. The small-sized cell 220 may trap a clot with a size ranging from 0.09mm to 5mm. The small-sized cell 220 helps to hold the clot during the retrieval procedure of the blood clot.

[0051] In an embodiment, the small-sized cell 220 (expanded view depicted in Fig. 4a) is produced by a continuous intricate strut (shown in Fig. 4al). Further, the small-sized cells 220 adjacent to the large-sized cells 225 may share a common strut within them. The common strut may have the structure corresponding to the large-sized cells 225 instead of the small-sized cells 220. Alternatively, the common strut may have the structure corresponding to the small sized cells 220 instead of the large-sized cells 225. In an embodiment, the common strut shared by the small-sized cells 220 and the large sized cells 225 have the structure corresponding to the large-sized cell 225.The continuous intricate strut of the small-sized cells 220 provides uniform lateral bending force to the device 1. The continuous intricate strut may include a peak 220a. The movement of adjacent peaks 220a of the intricate struts governs the radially expanded and radially crimped state of the device 1. In an embodiment, the movement of the peaks 220a of the intricate struts away from each other translates to the radial expansion of the device 1 and vice versa without any significant change in the length of the device 1. The intricate struts alleviate bending stress in the peak region 220a while crimping the device 1 which prevents fracture of the struts.

[0052] The intricate strut may include a square cross-section (shown in Fig. 3a). The square struts may make an angle with the longitudinal axis 'X' ranging from 40° to 60°. These angles provide better radial strength of the device to expand through the blood clot without damaging endothelial layer of the vessel.

[0053] When the device 1 is retrieved in the micro-catheter 400, all the intricate struts expand axially and self-assemble over each other (shown in Fig. 4a2) to reduce the diameter of the device 1 without any strut fracture by shear or bending force.

[0054] The intricate struts of the small-sized cell 220 may make an angle a with the longitudinal axis 'X' of the device 1. The intricate strut angle a may range from 30° to 70°, preferably from 43° to 53°. The small-sized cells 220 provide better expansion of the device 1 through the clot by transferring appropriate radial force due to intricate strut angle a. [0055] The intricate struts of the small-sized cell 220 may meet at a point defined by a canthus region 240. The canthus region 240 of the small-sized cells 220 may be cylindrical in shape and have a radius ranging from 0.01mm to 0.5mm preferably 0.02mm to 0.1mm. The canthus region of a small-sized cell 220 is a key parameter in crimping/retrieving of the device 1 in the micro-catheter 400. The canthus region 240 of the small-sized cell 220 provides reduced bending stress and allows slightly greater expanded diameter.

[0056] The large-sized cell 225 may have an area larger than the small-sized cell 220. In an embodiment, the large-sized cell 225 has three times the area of the small-sized cell 220. The large-sized cell 225 may have an area ranging from 10mm ² to 25mm ² , preferably from 15mm ² to 20mm ² . The large-sized cell 225 helps in better expansion of the device 1 through the clot.

[0057] As illustrated in exemplary Fig. 4b, a large-sized cell 225 is made up of two different strut structures, namely a long slide strut 225bl and a long straight strut 225b2. The long slide strut 225bl may have a length ranging from 4 mm to 7mm. In an embodiment, the length of the long slide strut 225bl is 5.5mm. The long straight strut 225b2 may have a length ranging from 3 mm to 5.5mm. In an embodiment, the length of the long straight strut 225b2 is 4.29mm. The large-sized cell 225 may trap a clot with a size ranging from 6mm to 15mm.The long slide strut 225bl and the long straight strut 225b2 provide more area to the large-sized cell 225 and allow better pro-lapse of the clot into the device 1. The long slide strut and long straight strut of the large-sized cells 225 cause the area bounded by the struts of the large-sized cell 225 to be larger, allowing for greater pro-lapse of the clot into the device 1.

[0058] The large-sized cell 225 may include a free tip 250 of the small-sized cell 220. The free tip 250 may enable mounting of the radiopaque markers 210 for better visualization of the device 1 under fluoroscopic imaging.

[0059] Two adjacent cells may be interconnected via connecting links 230a or 230b. For clarity, enlarged view of the connecting links 230a and 230b is depicted in Fig. 5. Each cell in a row is connected with each other by longitudinal cell connecting links 230a and each row of cells is connected with each other by lateral row connecting links 230b. A tread pattern (shown in Fig.

6a) so formed because of the arrangement of the cells, enables the radial end of the open reticulated structure align with each other producing a stratified pattern (shown in Fig. 6b). Due to the stratified pattern, the device 1 can be utilized in a range of vessel sizes. The valleys of two adjacent cells are connected via a longitudinal cell connecting link 230a while peaks of two adjacent cells are connected via a lateral row connecting link 230b. [0060] The longitudinal cell connecting links 230a may have a length ranging from 0.20 mm to 1.00 mm, preferably from 0.35 mm to 0.60 mm. The longitudinal cell connecting links 230a may have a width ranging from 0.10mm to 0.25mm, preferably from 0.14 mm to 0.20 mm. The longitudinal cell connecting link 230a prevents collapsing and/or bulking of the device 1 in the micro-catheter 400 during an interventional procedure.

[0061] The lateral row connecting link 230b may have a length ranging from 0.05mm to 0.20mm, preferably from 0.10mm to 0.15mm. The lateral row connecting link 230b may have a width ranging from 0.10mm to 0.20mm, preferably from 0.13mm to 0.17mm. The lateral row connecting links 230b enables the device 1 to bend laterally during navigation in a tortuous anatomy.

[0062] Further, as illustrated in Fig. 6a, each row of cells may be placed at an offset with respect to a circumferential axis. The offset may range from 0.30mm to 0.60mm circumferentially forming the tread like pattern. The tread pattern helps in crimping/retrieval of the device 1 with markers 210 in the aligned form i.e. when the device 1 is crimped in the micro-catheter 400 all the radiopaque markers 210 are aligned in a single row (shown in Fig. 9). The tread pattern enables the struts of the device 1 to be uniformly crimped over each other during loading and/or re-sheathing of the device 1 into the micro-catheter 400. Further, it helps in a uniform transition without bulking of the device 1 during deployment/expansion. The tread pattern also improves the circumference generated of the device land exposed to the clot for better retrieval of the clot.

[0063] Due to the tread pattern, both the radial ends of the open reticulated structure are aligned with each other as shown in Fig. 6b forming a stratified pattern. Due to stratified pattern the device can be utilized in a range of vessel sizes e.g. a device 1 with a diameter of 4mm, can be applied for the treatment of 2mm to 4mm diameter size vessels. The stratified pattern further provides an overlap/underlap leading to better concentric exposure of the device 1 to the better hold the clot.

[0064] The struts of the working region 200 may have a constant thickness throughout the length ranging from 30 microns to 100 microns, preferably from 60 microns to 80 microns. It is to be noted that the thinner struts induce less stress on the vessel wall, thus prevent trauma during the interventional procedure performed with the device 1. [0065] As illustrated in Fig. 1, the free tip 250 of the small-sized cell 220 may have the radiopaque marker 210 attached to it. Further, the distal most cells of the working region 200 may have the radiopaque marker 210 attached to the free tip 250. The markers 210 may have any structure known in the art. In an embodiment, the marker 210 is a tip-coil marker. The markers 210 of the device 1 may align in a single file when crimped inside the micro-catheter 400 (shown in Fig. 9). The marker 210 may also contribute in engaging and holding the clot.

[0066] Fig. 7 depicts an alternate embodiment of the device 1 for the retrieval of the clot from the neurovascular anatomy. As shown in figure, the design includes rows of large-sized cells followed by adjacent small-sized cells which are placed longitudinally and can be utilized for the clot retrieval process from the artery to remove clot with diameter more than 90micron. Large sized cells can engulf larger mass whereas small-sized cells can entangle smaller mass.

[0067] The device 1 may have a radial overlap on itself during the interventional procedure performed with the device 1. The overlap may be governed by the diameter of the vessel as well as the device 1. In an embodiment, if the diameter of the device 1 is same as the vessel diameter, the resulting overlap is illustrated in Fig. 8a. In another embodiment, the diameter of the vessel is smaller than the diameter of the device 1, the resulting overlap is illustrated in Fig. 8b and 8c. The radial overlap of the device 1 during the interventional procedure helps in effective retrieval and holding of the clot without damaging the vessel endothelial layer.

[0068] As shown in Fig. 10, when the cells of the device 1 may be retrieved in the micro catheter 400 all the intricate struts expand axially and assemble over each strut as shown in Fig. 9 to reduce the diameter of device 1 without strut fracture by shear or bending failure. The peaks 220a of the cells may come in contact or close to contact point while retrieval of the device 1. All the radiopaque markers 210 of the device 1 may be attached and aligned as shown in Fig. 9. The overall crimped profile of the device 1 can range from 0.5mm to 0.9mm. Area bounded by large-sized cells 225 may have the free tip 250 with the radiopaque marker 210 as shown in Fig. 9 for radiopacity during fluoroscopic imaging.

[0069] As depicted in Fig. 11a, a proximal end 120 of the end region 100 of the device 1 may be attached to a delivery wire 300. The delivery wire 300 may have a proximal end 310 and a distal end 320. In an embodiment, the proximal end 120 of the end region 100 is attached to the distal end 320 of the delivery wire 300. The delivery wire 300 may be made of any material known in the art. In an embodiment, the delivery wire 300 is made of nitinol. The delivery wire 300 may provide a means to transport/transfer/navigate the device 1 to a treatment site swiftly without any vessel damage.

[0070] As illustrated in Fig. lib, the delivery wire 300 may have a length ranging from 1700mm to 2300mm, preferably from 1800mm to 2100mm. The delivery wire 300 may be tapered at the distal end 320. The tapered distal end 320 may have a length ranging from 400mm to 500mm, preferably from 430mm to 450mm. The delivery wire 300 apart from the tapered distal end 320 may have a length ranging from 1400mm to 1700mm, preferably from 1500mm to 1600mm.

[0071] The delivery wire 300 may have a thickening agent 330 disposed at the distal end 320. In an embodiment, the thickening agent 330 is a coil. The thickening agent 330 may be made up of any radiopaque material including but without limitation platinum, gold, iridium, tantalum, platinum-iridium or platinum-tungsten, preferably platinum-tungsten. The thickening agent 330 may have a length ranging from 25mm to 35mm preferably from 27mm to 32mm. The thickening agent 330 may have a diameter ranging from 0.01mm to 0.13mm preferably from 0.03mm to 0.08mm.

[0072] The thickening agent 330 may be enveloped by a heat shrink tube. The heat shrink tube may include without limitation plastic tube or PTFE tube. The heat shrink tube may have a low coefficient of friction which reduces the thrust force required to push the thickening agent 330. The thickening agent 330 may provide sufficient strength to the distal tapered end 320 of the delivery wire 300 during the deployment of the device 1. The thickening agent 330 may also help transfer sufficient amount of thrust force and prevent kinking of the delivery wire 300 at the tapered distal end 320. Further, the thickening agent 330 may help the physician visualize and track the device 1 while deployed inside the intracranial vessels.

[0073] The clot retrieval device 1 along with the delivery wire 300 may be inserted in the human vasculature through the micro-catheter 400 as shown in Fig 11a. Initially, an introducer sheath of 5 Fr. to 9Fr. may be inserted in the femoral artery and further, a guide wire may be inserted in the human vasculature and guided to the neurovascular treatment site by the physician. Further micro-catheter 400 with size 2.1 Fr., 2.7 Fr. or 3 Fr. may be utilized for insertion of the blood flow resurrection device 1. Micro-catheter 400 is advanced over the guide wire. Once the micro-catheter 400 reaches the treatment site, the guide wire is removed and the clot retrieval device 1 with the delivery wire 300 is advanced at the treatment site.

[0074] The present invention may be supported by the following example: [0075] Example 1: The device 1 was subjected to an in vitro neuro vascular model for retrieval of an artificial clot/mass. The clot with different structure was placed in a tortuous path inside the neuro vascular model. The clot was partially penetrated by the device 1 in a micro-catheter 400. Thereafter, the device was expanded through the clot to entangle and engulf the clot. The device 1 successfully cleared/revascularized the in vitro model in a single pass. The diameter of the retrieved clot was assessed microscopically as tabulated below:

Therefore, it was established that the device 1 can retrieve clots as small as 90 microns due to its structure.

[0076] Example 2: Another device Ά' was subjected to an in-vitro neuro vascular model for retrieval of an artificial clot/mass. The device as per prior art design (shown in Fig. 12) includes a working region having a plurality of cells. The cells were symmetric having same shape and size. Each cell included a length of 4.6 mm, a width of 4.15 mm, strut width of 0.075 mm and strut length of 0.075 mm.

[0077] It was observed that the device Ά' was not able to expand through the clot due to absence of large (Giant) cells. Also, entangling/engulfing the large clot in the mesh was insufficient. Further, owing to the absence of large cells, while expansion the device Ά' in neurovascular model, the device was not able to expand leaving the clot mass behind at the treatment site.

[0078] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used.