Apparatus and methods for delivering coiled prostheses

Abstract

Methods and apparatus for delivering prostheses to body lumens, such as stents and grafts to blood vessels, utilize a delivery device which carries one or more linearized elements. The linearized elements assume non-linear configurations, particularly helical configurations, when advanced and released from the delivery device. By selectively controlling the length and/or number of elements delivered from the delivery device, extended and disseminated disease within the body lumens may be effectively treated.

1 . A catheter for delivering a prosthesis to a blood vessel, the catheter comprising: 
 an elongate catheter shaft having a proximal end, a distal end and a lumen therebetween;    a prosthetic element disposed in the lumen in a linearized configuration while constrained in the lumen and adapted to resiliently expand into a helical configuration which continuously engages a wall of the blood vessel along the entire length of said prosthetic element upon deployment from the lumen, the helical configuration being generally tubular with an open longitudinal passage therein adapted to provide a scaffold to inhibit closure of the blood vessel without substantially inhibiting blood flow through the longitudinal passage, and wherein the prosthetic element is separable into a first prosthesis having a first length and second prosthesis having a second length prior to release from the catheter shaft;    a pusher element for advancing the prosthetic element to expose the first length outside the lumen while the second length is retained in the lumen in the linearized configuration; and    a separating element coupled to the catheter shaft adapted to separate the first prosthesis from the second prosthesis such that the first prosthesis is released from the catheter shaft and expands to the helical configuration outside the lumen while the second prosthesis is retained in the catheter shaft in the linearized configuration.    
   
   
       2 . A catheter according to  claim 1 , wherein the prosthetic element is self-expanding.  
   
   
       3 . A catheter according to  claim 1 , wherein the separating element comprises a severing mechanism adapted to sever the first prosthesis from the second prosthesis.  
   
   
       4 . A catheter according to  claim 1 , wherein the separating element is movable relative to the prosthesis to allow the first prosthesis to be separated from the second prosthesis at any of a plurality of locations along the length of the prosthetic element.  
   
   
       5 . A catheter according to  claim 1 , further comprising an active substance disposed on the prosthetic element and adapted to be released therefrom in the blood vessel.  
   
   
       6 . A catheter according to  claim 5 , wherein the active substance inhibits hyperplasia after the first prosthesis has been deployed into the blood vessel.  
   
   
       7 . A catheter according to  claim 1 , wherein the prosthetic element is separable into a third prosthesis having a third length prior to release from the catheter shaft.  
   
   
       8 . A catheter according to  claim 1 , further comprising a length control member for adjusting the first length prior to release from the catheter.  
   
   
       9 . A catheter according to  claim 1 , wherein the first length is operator selectable.  
   
   
       10 . A catheter according to  claim 1 , wherein the first length is different than the second length.  
   
   
       11 . A catheter according to  claim 1 , wherein the first and second prostheses are unconnected in the lumen.  
   
   
       12 . A catheter according to  claim 1 , further comprising a mechanism on the catheter adapted to adjust the pitch of the first prosthesis as it is deployed.  
   
   
       13 . A catheter according to  claim 12 , wherein the pitch adjustment mechanism rotates the catheter shaft as the first prosthesis is advanced from the lumen.  
   
   
       14 . A catheter for delivering a prosthesis to a blood vessel, the catheter comprising: 
 a catheter body having a proximal end, a distal end, and at least one lumen;    a plurality of discrete helical elements disposed in the lumen of the catheter body, each of the plurality of discrete helical elements in a linearized configuration while constrained in the lumen and having a predetermined length and being separable from the remainder of the plurality of discrete helical elements;    means for advancing and releasing a selectable number of the plurality of discrete helical elements from the lumen while a second number of the plurality of discrete helical elements is retained in the lumen, wherein in an unconstrained condition the selectable number assumes and remains in a generally tubular non-linear configuration having an open longitudinal passage adapted to provide a scaffold to inhibit closure of the blood vessel upon release of the selectable number without substantially inhibiting blood flow therethrough; and    means for separating the selectable number of discrete helical elements from the second number of discrete helical elements after release of the selectable number of discrete helical elements while the second number of discrete helical elements is maintained in the lumen, whereby after release the length of the selectable number expands to the helical configuration outside the lumen and continuously engages a wall of the blood vessel and substantially matches the length of the stenotic region.    
   
   
       15 . A catheter as in  claim 14 , wherein the plurality of discrete helical elements are self-expanding.  
   
   
       16 . A catheter as in  claim 14 , wherein the means for separating the selectable number of discrete helical elements comprises a severing mechanism adapted to sever the selectable number of discrete helical elements from the second number of discrete helical elements.  
   
   
       17 . A catheter as in  claim 16 , wherein the severing mechanism comprises a separate element coupled to the catheter body.  
   
   
       18 . A catheter as in  claim 14 , wherein the means for separating comprises separating at least two discrete helical elements from the second number of discrete helical elements.  
   
   
       19 . A catheter as in  claim 14 , further comprising an active substance disposed on the plurality of discrete helical elements, wherein the active substance inhibits hyperplasia after the selectable number of discrete helical elements has been placed in the blood vessel.  
   
   
       20 . A catheter as in  claim 14 , wherein the catheter body can be rotated so that the selectable number of discrete helical elements remains rotationally stationary relative to the wall of the blood vessel as the selectable number is released from the catheter body.  
   
   
       21 . A method for delivering a prosthesis to a stenotic region of a blood vessel, said method comprising: 
 introducing a delivery device to an interior of the blood vessel, wherein said device carries a plurality of discrete helical elements, each of the plurality of discrete helical elements having a predetermined length and being separable from the remainder of helical elements;    advancing a first number of the discrete helical elements relative to the delivery device within the interior of the blood vessel, wherein the first number assumes a non-linear configuration which traverses a surface region of the interior of the blood vessel as the first number is advanced;    selecting a first number of the discrete helical elements so that the combined length of the first number of discrete helical elements substantially matches the length of the stenotic region of the blood vessel;    separating the first number of discrete helical elements from a second number of discrete helical elements;    releasing the first number of the one or more discrete helical elements in the non-linear configuration from the delivery device into the stenotic region of the blood vessel, wherein upon release the first number forms and remains a generally tubular scaffold to inhibit closure of the stenotic region without substantially inhibiting blood flow through the blood vessel; and    maintaining the second number of the discrete helical elements in the delivery device after the first number is released.    
   
   
       22 . A method as in  claim 21 , wherein plurality of discrete helical elements are at least partially malleable and wherein advancing comprises deforming the first number of discrete helical elements into a preselected geometry as they are advanced.  
   
   
       23 . A method as in  claim 22 , wherein the preselected geometry is helical.  
   
   
       24 . A method as in  claim 23 , wherein advancing comprises drawing the delivery device relative to the body lumen and pushing the first number of discrete helical elements from the delivery device as the delivery device is drawn.  
   
   
       25 . A method as in  claim 24 , wherein the rate of drawing the delivery device is varied relative to the rate of pushing the first number of discrete helical elements in order to control the pitch of the helical geometry.  
   
   
       26 . A method as in  claim 21 , wherein the plurality of discrete helical elements are pre-shaped with a spring memory and wherein advancing comprises releasing the first number of discrete helical elements from a linearized constraint.  
   
   
       27 . A method as in  claim 26 , wherein the constraint is a passage within the delivery device and wherein advancing comprises pushing the first number of discrete helical elements from the passage as the device is drawn relative to the body lumen.  
   
   
       28 . A method as in  claim 27 , wherein the rate of drawing the delivery device is varied relative to the rate of pushing the first number of discrete helical elements from the delivery device in order to control the pattern in which the first number of discrete helical elements is laid on the surface region.  
   
   
       29 . A method as in  claim 1 , wherein the plurality of discrete helical elements are composed at least partly of a bioabsorbable material.  
   
   
       30 . A method as in  claim 29 , wherein the plurality of discrete helical elements comprise a metal scaffold covered with a polymeric layer  
   
   
       31 . A method as in  claim 30 , wherein the first number of discrete helical elements are advanced so that they traverse a region of the blood vessel with diffuse disease over a length of at least 10 mm.  
   
   
       32 . A method as in  claim 30 , wherein the first number of discrete helical elements are coated or loaded with an active substance which inhibits hyperplasia after the first number of discrete helical elements have been placed in the blood vessel.  
   
   
       33 . A method as in  claim 21 , wherein separating the first number comprises severing the first number of discrete helical elements from the second number of discrete helical elements.  
   
   
       34 . A method as in  claim 21 , wherein the delivery device carries a plurality of linearized elements and releasing the first number comprises delivering a selected number of at least two linearized elements to the stenotic region.