Systems, methods and devices for embolic protection

Abstract

Embodiments of the present disclosure are directed to systems, methods and devices for providing embolic protection in a patient. In some embodiments, the device is configured for implantation in a body vessel including fluid flow. The device may assume, or be constrained to assume, an undeployed state and a deployed state. In the undeployed state, the device or a portion thereof has a substantially linear shape configured to reside in the lumen of a thin needle having a diameter of less than about 0.5 mm (for example), in the deployed state, the device has a primary axis. When the device is implanted the primary axis is approximately perpendicular to the fluid flow. In some embodiments, the device comprises a thin filament body. In the deployed state the filament takes a helical shape. Emboli that are larger than the distance between consecutive turns or windings of the helix are thus filtered by the device and are prevented from causing deleterious conditions such as stroke or pulmonary embolism. The device may be made of a super-elastic alloy. Thus, the device may transition between the undeployed and the deployed states without plastic deformation. Delivery systems and method for implanting such devices are also disclosed.

What is claimed is: 
     
         1 . A vascular embolic protection device for deployment at an implantation site within a blood vessel, the device comprising:
 a filament having a length, proximal and distal ends and a diameter between about 50 and about 500 microns, wherein the filament is configured to include an undeployed state and a deployed state, and wherein:   in the undeployed state, at least a portion of the device is configured to fit within the lumen of a delivery tube; and   in the deployed state, the device includes a primary axis which is approximately perpendicular to the blood flow direction.   
     
     
         2 . The device of  claim 1 , wherein at least one of the tube and the distal end of the device is configured for puncturing the blood vessel in the vicinity of the implantation site. 
     
     
         3 . The device of  claim 1 , wherein the filament includes a substantially circular cross-section. 
     
     
         4 . The device of  claim 1 , wherein the diameter of the filament is less than about 0.2 mm. 
     
     
         5 . The device of  claim 1 , wherein the filament further comprises a proximal segment near the proximal end and in the deployed state the proximal segment is substantially collinear with said primary axis. 
     
     
         6 . The device of  claim 1 , wherein at substantially every point along its length the radius of curvature exceeds a critical value equal to the diameter of the filament divided by about twice the critical strain of the material from which the filament is made. 
     
     
         7 . The device of  claim 6 , wherein the critical value is greater than about 0.6 mm. 
     
     
         8 . The device of  claim 1 , wherein in the deployed state the filament has the shape of a helix comprising a plurality of turns. 
     
     
         8 . The device of  claim 8 , wherein the plurality of turns vary in diameter. 
     
     
         9 . The device of  claim 8 , wherein the number of turns is between one and twenty. 
     
     
         11 . The device of  claim 8 , wherein a plurality of windings approximately trace the shape of a spherical shell having a diameter. 
     
     
         12 . The device of  claim 11 , wherein the diameter of the spherical shell is less than or equal to the diameter of the vessel. 
     
     
         13 . The device of  claim 8 , wherein the distance between consecutive windings is greater than about 0.7 mm. 
     
     
         14 . The device of  claim 8 , wherein the distance between consecutive windings is less than about 1.5 mm. 
     
     
         15 . The device of  claim 1 , further comprising one or more of a radiopaque marker, an echogenic marker, a radioactive marker, a magnetic marker, and a magnetic resonance marker. 
     
     
         16 . The device of  claim 1 , wherein the filament is made from at least one of: a metal, a plastic, a natural polymer, a shape memory alloy, a super elastic alloy, a biodegradable material, a bioresorbable material, and a bioabsorbable material. 
     
     
         17 . The device of  claim 1 , further comprising an end piece at its proximal end, an end piece at its distal end, or both. 
     
     
         18 . The device of  claim 17 , wherein each of the end pieces comprises at least one of a radiopaque marker, an echogenic marker, a radioactive marker, a magnetic marker, a magnetic resonance marker, an anchor, a non-traumatic tip, a bearing, and a retrieval knob. 
     
     
         19 . The device of  claim 17 , wherein at least one of the end pieces is configured with an undeployed and a deployed state. 
     
     
         20 . The device of  claim 17 , wherein at least one of end pieces comprises an anchor, and wherein the anchor comprises at least one of: a loop, a roughened surface, a barb, a micro-barb, a hook, a bulge, and a material configured to enlarge upon contact with an aqueous environment. 
     
     
         21 . The device of  claim 17 , wherein at least one of the end pieces is integral with said filament. 
     
     
         22 . The device of  claim 18 , wherein each of the radiopaque marker, the echogenic marker, the radioactive marker, the magnetic marker, the magnetic resonance marker, the anchor, the non-trauumatic tip, the bearing, and the retrieval knob need not be physically distinct. 
     
     
         23 . The device of  claim 18 , wherein said bearing is configured to release accumulated torsion or to prevent the build-up of torsion in the filament. 
     
     
         24 . The device of  claim 1 , wherein the filament is substantially straight in the deployed state. 
     
     
         25 . The device of  claim 1 , wherein the shape of the filament is substantially similar in both the undeployed and the deployed states. 
     
     
         26 . The device of  claim 1 , further comprising two or more filaments, wherein each filament has a length, a diameter, a proximal filament end, and a distal filament end. 
     
     
         26 . The device of  claim 26 , wherein the filaments are joined at the proximal end and at the distal end of the device. 
     
     
         28 . The device of  claim 26 , wherein said two or more filaments each have a helical shape. 
     
     
         29 . The devices of any of  claims 1 - 28 , wherein embolic protection is provided against stroke or pulmonary embolism, and wherein the patient's vessel is any of: an artery, a vein, an aorta, a common carotid artery, an internal carotid artery, a subclavian artery, brachiocephalic artery, a renal artery, a vertebral artery, a superficial femoral vein, a deep femoral vein, a popliteal vein, an iliac vein, an inferior vena cava, or a superior vena cava. 
     
     
         30 . A method for providing embolic protection in a patient, the method comprising implanting a filament shaped approximately as a helix in a vessel of the patient, said vessel comprising a fluid flow, such that the axis of the helix is approximately perpendicular to the fluid flow direction.