Introducer sheaths, thrombus collection devices and associated methods

Abstract

A sheath comprises an elastomeric tube having a self-expanding scaffold coupled to a wall. The scaffold can expand to a diameter larger than the tube diameter to provide an enlarged distal opening. An aspiration catheter has a balloon and an aspiration port so that occlusive material can be removed from a blood vessel by drawing the balloon through the vessel while simultaneously aspirating through the port.

1 . A vascular sheath comprising:
 a proximal shaft comprising an unsupported tube of elastomeric material, the proximal shaft being radially collapsible and radially expandable, but not self-expanding; and   an elastomeric, tubular distal end portion extending distally from a distal end of the proximal shaft, the distal end portion having a larger diameter than the proximal shaft and forming a distal end opening of the sheath, the distal end portion being coupled to a circumferentially expandable member which makes the distal end portion circumferentially self-expandable.   
     
     
         2 . A sheath as in  claim 1 , wherein the circumferentially expandable member is embedded in a wall of the distal end portion. 
     
     
         3 . A sheath as in  claim 1 , wherein the circumferentially expandable member is secured to a surface of a wall of the distal end portion. 
     
     
         4 . A sheath as in  claim 1 , wherein the circumferentially expandable member is disposed in an annular space formed in a wall of the sheath so that said member can foreshorten as it expands without deforming the wall. 
     
     
         5 . A medical device comprising:
 a non-expandable outer sheath having an inner lumen, the outer sheath housing the proximal shaft and the distal end portion of the sheath of  claim 1  in the inner lumen; and   a dilator having a dilator tip projecting distally from a distal end of the outer sheath.   
     
     
         6 . The medical device of  claim 5 , wherein the outer sheath houses the distal end portion in a circumferentially collapsed state. 
     
     
         7 . The medical device of  claim 6 , further comprising a dilator shaft extending proximally from the dilator tip, through the distal end portion and the proximal shaft of the sheath. 
     
     
         8 . A sheath comprising:
 a tubular body having a proximal end, a distal end, and an axial passage therethrough; wherein the tubular body is formed at least partially from an elastomeric material and has an open diameter when fully open; and   a self-expanding scaffold coupled to at least a portion of tubular body;   wherein the self-expanding scaffold has an expanded diameter which is at least as large as the open diameter of the tubular body.   
     
     
         9 . A sheath as in  claim 8 , further comprising a shaft extending from the proximal end of the tubular body. 
     
     
         10 . A sheath as in  claim 9 , wherein the shaft comprises an extension of the scaffold. 
     
     
         11 . A sheath as in  claim 10 , wherein the scaffold is a coil and the shaft is an integral extension of the coil. 
     
     
         12 . A sheath as in  claim 8 , wherein the scaffold has a cylindrical geometry when expanded. 
     
     
         13 . A sheath as in  claim 8 , wherein the scaffold has a tapered geometry when expanded. 
     
     
         14 . A sheath as in  claim 8 , further comprising a catheter body, wherein the sheath and the scaffold are disposed over a distal end of the catheter body. 
     
     
         15 . A sheath as in  claim 8 , wherein the self-expanding scaffold is embedded in a wall of the sheath. 
     
     
         16 . A sheath as in  claim 8 , wherein the self-expanding scaffold is secured to a surface of a wall of the sheath. 
     
     
         17 . A sheath as in  claim 8 , wherein the self-expanding scaffold is disposed in an annular space formed in a wall of the sheath so that said scaffold can foreshorten as it expands without deforming the wall. 
     
     
         18 . A sheath as in  claim 8 , wherein the tubular body has an expanded diameter in the range from 3 Fr. To 24 Fr. 
     
     
         19 . A shaft as in  claim 18 , wherein the self-expanding scaffold has an expanded diameter in the range from 3 Fr. to 28 Fr. 
     
     
         20 . A sheath as in  claim 8 , wherein the sheath has a length in the range from 10 cm to 200 cm. 
     
     
         21 . A method for aspirating occlusive material form a patient's vasculature, said method comprising:
 providing an a catheter comprising a shaft, an expandable member at a distal end of the shaft, an aspiration port on the shaft proximal to the expandable member, and an aspiration lumen extending from the aspiration port to a proximal end of the shaft;   introducing the catheter to blood vessel so that the expandable member lies on a distal side of the occlusive material;   expanding the expandable member on said distal side of the clot; and   drawing the catheter proximally while aspirating through the lumen and port to remove the occlusive material from the blood vessel.   
     
     
         22 . A method as in  claim 21 , wherein the catheter is introduced into a peripheral blood vessel. 
     
     
         23 . A method as in  claim 21 , wherein the catheter is introduced into an arterio-venous graft or fistula. 
     
     
         24 . A method as in  claim 23 , wherein the catheter consists of a single balloon. 
     
     
         25 . A method as in  claim 24 , wherein the catheter has only a single aspiration port. 
     
     
         26 . A method as in  claim 21 , wherein drawing and aspiration are together able to remove substantially all the occlusive material. 
     
     
         27 . A method as in  claim 21 , further comprising collecting occlusive material in a separate sheath disposed coaxially over the catheter, wherein the catheter draws a portion of the occlusive material into a proximal opening in the sheath.