Apparatus and methods for delivery of multiple distributed stents

Abstract

Blood vessels and other body lumens are stented using multiple, discreet stent structures. Stent structures may be balloon expandable or self-expanding and are delivered by a delivery catheter which is repositioned to spaced-apart delivery sights. By coating the stents with particular biologically active substances, hyperplasia within and between the implanted stents can be inhibited. An exemplary delivery catheter comprises a catheter body having both a pusher rod for advancing the stents relative to a sheath and a reciprocatable delivery catheter for implanting the stents.

1 . A method for stenting extended lengths of a body lumen, said method comprising: 
 introducing a catheter carrying a plurality of radially expansible prostheses to a stenotic lesion within said body lumen, wherein said prostheses are arranged end-to-end and covered by a sheath;    retracting the sheath by a first distance to uncover a first multiplicity of the prostheses, wherein the uncovered prostheses do not expand during retraction; and    radially expanding each of said first multiplicity of uncovered prostheses simultaneously at a first location within said stenotic lesion while at least one other prosthesis is retained on the catheter, said first multiplicity of prostheses engaging a wall of the body lumen with sufficient radial force to maintain patency thereof, said prostheses being spaced apart from each other after expansion by a distance small enough to inhibit hyperplasia therebetween.    
   
   
       2 . A method as in  claim 1 , further comprising inflating a balloon within said prostheses to effect expansion.  
   
   
       3 . A method as in  claim 2 , wherein inflating comprises inflating a balloon disposed both under said prostheses to be expanded and under at least some prostheses which remain under the sheath, wherein inflation of the balloon under the sheath is constrained by the sheath to prevent expansion of the at least some prostheses.  
   
   
       4 . A method as in  claim 2 , further comprising engaging a proximal end of the plurality of prostheses with a pusher tube to axially restrain the prostheses as the sheath is retracted.  
   
   
       5 . A method as in  claim 4 , further comprising engaging one of the prostheses with a valve member coupled with the distal end of the sheath.  
   
   
       6 . A method as in  claim 5 , further including retracting the sheath and the pusher tube to separate prostheses proximal to the valve member from the first multiplicity of prostheses.  
   
   
       7 . A method as in  claim 6 , wherein separating comprises inflating a balloon disposed under said first multiplicity of prostheses.  
   
   
       8 . A method as in  claim 1 , further comprising heating the uncovered prostheses to effect expansion.  
   
   
       9 . A method as in  claim 8 , wherein heating comprises directing a heated medium through the catheter to the uncovered prostheses.  
   
   
       10 . A method as in  claim 8 , wherein heating comprises energizing a heating element positioned adjacent to the uncovered prostheses.  
   
   
       11 . A method as in  claim 8 , further comprising engaging a proximal end of the plurality of prostheses with a pusher tube to axially restrain the prostheses as the sheath is retracted.  
   
   
       12 . A method as in  claim 1 , wherein said prostheses are resilient and radially constrained within the sheath, wherein the prostheses radially expand as the sheath is retracted.  
   
   
       13 . A method as in  claim 12 , further comprising engaging a proximal end of the plurality of prostheses with a pusher tube to axially restrain the prostheses as the sheath is retracted.  
   
   
       14 . A method as in  claim 1 , further comprising repositioning the catheter and further retracting the sheath by a second distance to uncover a second multiplicity of prostheses, said second multiplicity of uncovered prostheses radially expanding at a second location within said target site.  
   
   
       15 . A method as in  claim 1 , wherein the body lumen is a blood vessel.  
   
   
       16 . A method as in  claim 1 , wherein the prostheses have at least one agent disposed thereon.  
   
   
       17 . A method as in  claim 16 , wherein the agent inhibits hyperplasia.  
   
   
       18 . A method as in  claim 17 , wherein the agent is biologically active.  
   
   
       19 . A method as in  claim 18 , wherein the biologically active agent is selected from the group consisting of anti-neoplastic drugs such as paclitaxel, methotrexate, and batimastal; antibiotics such as doxycycline, tetracycline, rapamycin, and actinomycin; immunosuppressants such as dexamethasone and methyl prednisolone; nitric oxide sources such as nitroprussides; estrogen; and estradiols.  
   
   
       20 . A method as in  claim 17 , wherein the agent is biologically inert.  
   
   
       21 . A method as in  claim 20 , wherein the biologically inert agent is selected from the group consisting of collagen, polyethylene glycol (PEG), polyglycolic acids (PGA), ceramic material, platinum and gold.  
   
   
       22 . A method for stenting extended lengths of a body lumen, said method comprising: 
 introducing a catheter carrying at least three discrete stents;    releasing at least a first stent from the catheter at a first location in the body lumen;    repositioning the catheter;    releasing at least a second stent from the catheter at a second location, wherein at least a third stent from the catheter is released and radially expanded simultaneously with one of said first or second stent, the third stent being spaced apart from the first or second stent after release by a distance which is small enough to inhibit hyperplasia therebetween said first, second, and third stents engaging a wall of the body lumen with sufficient radial force to maintain patency thereof.    
   
   
       23 . A method as in  claim 22 , wherein the catheter carries at least four discrete stents, further comprising repositioning the catheter and releasing at least a fourth stent at a fourth location.  
   
   
       24 . A method as in  claim 23 , wherein the catheter carries at least five discrete stents, further comprising repositioning the catheter and releasing at least a fifth stent at a fifth location.  
   
   
       25 . A method as in  claim 22 , wherein the body lumen comprises a blood vessel.  
   
   
       26 . A method as in  claim 25 , wherein the stents are released at locations which span a length of at least 3 mm in the blood vessel.  
   
   
       27 . A method as in  claim 25 , where at least two stents are positioned on opposite sides of an opening in the blood vessel to a side branch.  
   
   
       28 . A method as in  claim 22 , wherein releasing the stents comprises expanding a balloon within the stents.  
   
   
       29 . A method as in  claim 22 , wherein releasing the stents comprises releasing the stents from constraint and allowing the stents to self-expand.  
   
   
       30 . A method as in  claim 22 , wherein the stents have at least one agent disposed thereon.  
   
   
       31 . A method as in  claim 30 , wherein the agent inhibits hyperplasia.  
   
   
       32 . A method as in  claim 30 , wherein the agent is biologically active.  
   
   
       33 . A method as in  claim 32 , wherein the biologically active agent is selected from the group consisting of anti-neoplastic drugs such as paclitaxel, methotrexate, and batimastal; antibiotics such as doxycycline, tetracycline, rapamycin, and actinomycin; immunosuppressants such as dexamethasone and methyl prednisolone; nitric oxide sources such as nitroprussides; estrogen; and estradiols.  
   
   
       34 . A method as in  claim 30 , wherein the agent is biologically inert.  
   
   
       35 . A method as in  claim 34 , the biologically inert agent is selected from the group consisting of collagen, PEG, PGA, ceramic material, platinum and gold.  
   
   
       36 . A method as in  claim 16 , wherein the agent is disposed in a bioresorbable material formed on or within the prostheses.  
   
   
       37 . A method as in  claim 36 , wherein the bioresorbable material is selected from the group consisting of polyethylene glycol, collagen, gelatin, polyglocolic acids, and polylactic acids.  
   
   
       38 . A method as in  claim 30 , wherein the agent is disposed in a bioresorbable material formed on or within the prostheses.  
   
   
       39 . A method as in  claim 38 , wherein the bioresorbable material is selected from the group consisting of polyethylene glycol, collagen, gelatin, polyglycolic acids, and polylactic acids.  
   
   
       40 . The method of  claim 1 , wherein the distance between adjacent prostheses after expansion in the body lumen is no more than about 1 mm.  
   
   
       41 . The method of  claim 22 , wherein the distance between the third stent and the first or second stent after expansion is no more than about 1 mm.