Debulking catheter

Abstract

A catheter includes a rotatable cutter in a catheter body adjacent a window and operatively connected to a rotatable shaft for rotation therewith. The rotatable cutter includes a proximally-facing cutting edge. The rotatable cutter is selectively positionable to a cutting position in which the rotatable cutter extends partially outside the window to expose the cutting edge such that the catheter can be moved proximally within the body lumen as the rotatable cutter is rotating to remove tissue from the lumen and direct the removed tissue through the window and into a removed-tissue lumen.

What is claimed is: 
     
         1 . A catheter for removing tissue from a body lumen of a subject, the catheter comprising:
 an elongate catheter body having proximal and distal ends and a longitudinal axis extending therebetween, the catheter body being sized and shaped for introduction into the body lumen of the subject;   a window adjacent the distal end of the catheter body and extending generally transversely into the catheter body relative to the longitudinal axis of the catheter body for receiving removed tissue from the body lumen;   a removed-tissue lumen in the catheter body and in communication with the window for receiving removed tissue passing through the window;   a rotatable shaft having proximal and distal ends and a longitudinal axis extending therebetween, the shaft extending longitudinally within the catheter body and configured for selective rotation about its longitudinal axis relative to the catheter body;   a rotatable cutter in the catheter body adjacent the window and operatively connected to the rotatable shaft for rotation therewith, the rotatable cutter including a proximally-facing cutting edge, wherein the rotatable cutter is selectively positionable to a cutting position in which the rotatable cutter extends partially outside the window to expose the cutting edge such that the catheter can be moved proximally within the body lumen as the rotatable cutter is rotating to remove tissue from the lumen and direct the removed tissue through the window and into the removed-tissue lumen.   
     
     
         2 . The catheter set forth in  claim 1 , wherein the rotatable cutter is selectively lockable in the cutting position. 
     
     
         3 . The catheter set forth in  claim 2 , wherein the cutting edge extends about 0.025 mm to 0.64 mm outside the window when the rotatable cutter is in the cutting position. 
     
     
         4 . The catheter set forth in  claim 1 , wherein the catheter includes a transport mechanism for moving the removed tissue proximally within the removed-tissue lumen. 
     
     
         5 . The catheter set forth in  claim 4 , wherein the rotatable shaft extends into the removed-tissue lumen, and the transport mechanism comprises a helical screw on the rotatable shaft. 
     
     
         6 . The catheter set forth in  claim 1 , wherein the rotatable shaft is selectively moveable longitudinally relative to the catheter body to impart selective longitudinal movement of the rotatable cutter relative to the window. 
     
     
         7 . The catheter set forth in  claim 1 , further comprising a stationary cutting element for removing tissue from the lumen, the stationary cutting element located adjacent to the window. 
     
     
         8 . The catheter set forth in  claim 7 , wherein the rotatable shaft is selectively moveable longitudinally relative to the catheter body to impart selective longitudinal movement of the rotatable cutter relative to the stationary cutting element between a first longitudinal position, in which the rotatable cutter is in registration with the window and the cutting edge of the rotatable cutter is spaced a first longitudinal distance from the stationary cutting element to define a first effective open area of the window leading to the removed-tissue lumen, and a second longitudinal position, in which the rotatable cutter is in registration with the window and the cutting edge of the rotatable cutter is spaced a second longitudinal distance from the stationary cutting element to define a second effective open area of the window leading to the removed-tissue lumen, wherein the first longitudinal distal is greater than the second longitudinal distance and the first effective open area of the window is greater than the second effective open area of the window. 
     
     
         9 . The catheter set forth in  claim 1 , wherein the rotatable cutter is selectively positionable to a non-cutting position in which an entirety of the rotatable cutter is disposed within the catheter body and the cutting edge is not exposed through the window. 
     
     
         10 . A catheter for removing tissue from a body lumen of a subject, the catheter comprising:
 an elongate catheter body having proximal and distal ends and a longitudinal axis extending therebetween, the catheter body being sized and shaped for introduction into the body lumen of the subject;   a window adjacent the distal end of the catheter body and extending generally transversely into the catheter body relative to the longitudinal axis of the catheter body for receiving removed tissue from the body lumen;   a removed-tissue lumen in the catheter body and in communication with the window for receiving removed tissue passing through the window;   a stationary cutting element for removing tissue from the body lumen, the stationary cutting element located adjacent to the window and configured to direct tissue cut from the body lumen toward the window;   a plunger assembly in the elongate catheter body, the plunger assembly including
 a shaft having proximal and distal ends and a longitudinal axis extending therebetween, the shaft extending longitudinally through the elongate catheter body and configured for rotation about its longitudinal axis and longitudinal movement relative to the catheter body; 
 a plunger secured adjacent the distal end of the shaft within the removed-tissue lumen, the plunger configured to rotate with the shaft and move longitudinally with the shaft within the removed-tissue lumen, wherein the plunger is longitudinally moveable within the removed-tissue lumen between a first longitudinal position, in which the plunger is in registration with the window and spaced a first longitudinal distance from the stationary cutting element to define a first effective open area of the window leading to the removed-tissue lumen, and a second longitudinal position, in which the plunger is in registration with the window and spaced a second longitudinal distance from the stationary cutting element to define a second effective open area of the window leading to the removed-tissue lumen, wherein the first longitudinal distal is greater than the second longitudinal distance and the first effective open area of the window is greater than the second effective open area of the window. 
   
     
     
         11 . The catheter set forth in  claim 10 , wherein the window is at least partially defined by a proximal window edge and a distal window edge of the catheter body, wherein the stationary cutting element is adjacent said proximal window edge. 
     
     
         12 . The catheter set forth in  claim 11 , wherein the stationary cutting element extends along said proximal window edge. 
     
     
         13 . The catheter set forth in  claim 12 , wherein the stationary cutting element is V-shaped. 
     
     
         14 . The catheter set forth in  claim 11 , wherein the stationary cutting element faces distally. 
     
     
         15 . The catheter set forth in  claim 14 , wherein the first longitudinal position of the plunger is distal to the second longitudinal position of the plunger. 
     
     
         16 . The catheter set forth in  claim 10 , wherein the plunger includes a cutting element. 
     
     
         17 . The catheter set forth in  claim 16 , wherein plunger comprises a cutting wheel facing proximally. 
     
     
         18 . The catheter set forth in  claim 17 , wherein the shaft of the plunger assembly includes a helical screw for transporting removed plaque proximally within the removed-tissue lumen.