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 the body lumen, wherein the prostheses are arranged end-to-end on an expandable member;   radially expanding at least some of the plurality of prostheses simultaneously at a first location within the stenotic lesion, wherein the expanded prostheses have a combined length of between 40 mm to 100 mm and engage a wall of the body lumen with sufficient radial force to maintain patency thereof, the expanded prostheses being spaced apart from each other after expansion by a distance no more than about 1 mm so as to inhibit hyperplasia therebetween.   
   
   
       2 . A method as in  claim 1 , wherein a sheath covers at least some of the plurality of prostheses, the method further comprising retracting a sheath by a first distance to uncover the prostheses for radial expansion and wherein the uncovered prostheses do not expand during retraction of the sheath. 
   
   
       3 . A method as in  claim 1 , wherein at least one other prosthesis remains on the catheter in the unexpanded configuration while the prostheses are radially expanded. 
   
   
       4 . A method as in  claim 1 , wherein the expandable member comprises a balloon and radially expanding comprises inflating the balloon. 
   
   
       5 . A method as in  claim 2 , wherein the expandable member comprises a balloon and the balloon is disposed under the prostheses to be radially expanded and at least another prosthesis, and wherein expansion of the at least another prosthesis is constrained by the sheath when the expandable member is expanded. 
   
   
       6 . A method as in  claim 2 , further comprising engaging a proximal end of the plurality of prostheses with a pusher tube to restrain axial movement thereof as the sheath is retracted. 
   
   
       7 . A method as in  claim 2 , further comprising engaging at least one of the plurality of prostheses with a valve member disposed near a distal end of the sheath. 
   
   
       8 . A method as in  claim 6 , further comprising retracting the pusher tube along with the sheath in order to separate the prostheses to be expanded from any remaining prostheses on the delivery catheter. 
   
   
       9 . A method as in  claim 1 , further comprising heating the uncovered prostheses to effect expansion thereof. 
   
   
       10 . A method as in  claim 1 , wherein the prostheses are balloon expandable. 
   
   
       11 . A method as in  claim 1 , wherein the plurality of prostheses are resilient and radially constrained by a sheath disposed at least partially thereover, wherein the prostheses radially self-expand as the sheath is retracted. 
   
   
       12 . A method as in  claim 1 , further comprising repositioning the catheter and further expanding additional prostheses at a second location within the stenotic lesion. 
   
   
       13 . A method as in  claim 1 , wherein the body lumen is a blood vessel. 
   
   
       14 . A method as in  claim 1 , wherein the prostheses releasably carry at least one agent disposed thereon. 
   
   
       15 . A method as in  claim 14 , wherein the agent inhibits hyperplasia. 
   
   
       16 . A method as in  claim 1 , further comprising dilating the radially expanded prostheses with the expandable member after expansion thereof. 
   
   
       17 . A catheter for stenting extended lengths of a body lumen, said catheter comprising:
 a catheter body having a proximal end and a distal end;   at least three discrete stents carried near a distal end of the catheter body, the discrete stents radially expandable from a contracted configuration to an expanded configuration in which the stents engage a wall of the body lumen;   a deployment mechanism for selectively deploying the stents both independently and in groups from the catheter body within the body lumen, the deployment mechanism being adapted to deploy a multiplicity of stents while at least one other stent is retained in the catheter unconnected to the multiplicity after the multiplicity of stents are released from the catheter and are in the expanded configuration, wherein the deployment mechanism allows the multiplicity of stents to radially expand into the expanded configuration with a distance between adjacent stents small enough to inhibit hyperplasia therebetween.   
   
   
       18 . A catheter as in  claim 17 , wherein the catheter body is free of fixed structures intervening between the stents 
   
   
       19 . A catheter as in  claim 17 , comprising at least four discrete stents carried near the distal end of the catheter body. 
   
   
       20 . A catheter as in  claim 19 , comprising at least five discrete stents carried near the distal end of the catheter body. 
   
   
       21 . A catheter as in  claim 17 , wherein the deploying means comprises at least three independently inflatable balloons, wherein each balloon carries at least one stent. 
   
   
       22 . A catheter as in  claim 17 , wherein the deploying mechanism comprises a single balloon reciprocatably mounted within the catheter body and a pusher for successively loading stents over the balloon. 
   
   
       23 . A catheter as in  claim 17 , wherein the deploying mechanism comprises a radial restraint which holds the stents in a radially collapsed configuration and which can be selectively retracted to release the stents independently or in groups. 
   
   
       24 . A catheter as in  claim 17 , wherein the deploying mechanism comprises a radial restraint which holds the stents in a radially collapsed configuration and a pusher for holding the stents in place while the radial restraint is retracted to expose the stents from the distal end of the catheter body independently or in groups. 
   
   
       25 . A catheter as in  claim 24 , wherein the radial restraint comprises a sheath having a valve member at its distal end for engaging a proximal stent to separate the proximal stent from a distal stent. 
   
   
       26 . A catheter as in  claim 17 , wherein the stents have at least one agent disposed thereon. 
   
   
       27 . A catheter as in  claim 26 , wherein the agent is disposed in a bioresorbable material formed on or within the prostheses. 
   
   
       28 . A catheter as in  claim 27 , wherein the bioresorbable material is selected from the group consisting of polyethylene glycol, collagen, gelatin, polyglycolic acids, and polylactic acids. 
   
   
       29 . A catheter as in  claim 26 , wherein the agent inhibits hyperplasia. 
   
   
       30 . A catheter as in  claim 29 , wherein the agent is biologically active. 
   
   
       31 . A catheter as in  claim 17 , 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 dexamethosone and methyl prednisolone; nitric oxide sources such as nitroprussides; estrogen; and estradiols. 
   
   
       32 . A catheter as in  claim 29 , wherein the agent is biologically inert. 
   
   
       33 . A catheter as in  claim 32 , wherein the biologically inert agent is selected from the group consisting of collagen, PEG, PGA, ceramic material, platinum and gold. 
   
   
       34 . A catheter as in  claim 17 , wherein the stents are composed at least partly of a bioabsorbable material. 
   
   
       35 . A catheter as in  claim 34 , wherein a bioactive substance is disposed in the bioabsorbable material and is released over time as the material degrades. 
   
   
       36 . A catheter as in  claim 34 , wherein the bioabsorbable material is formed on or within a scaffold composed of a non-bioabsorbable material. 
   
   
       37 . The catheter of  claim 17 , wherein the deployment mechanism allows the stents to expand such that the distance between the adjacent stents after expansion is no more than about 1 mm. 
   
   
       38 . A catheter system for implanting prostheses in a body lumen, said catheter system comprising:
 a catheter body having a proximal end and a distal end;   at least two radially expandable prostheses carried near a distal end of the catheter body, the at least two prostheses radially expandable from a contracted configuration to an expanded configuration in which the prostheses engage a wall of the body lumen, the at least two prostheses being independently deployable of one another; and   an expansion element disposed near the distal end of the catheter body having an expandable portion adapted to radially expand one or more of the at least two prostheses into engagement with a wall of the body lumen, the expandable portion having an expandable length which is operator-adjustable from the proximal end such that expanded length may be expanded while a remaining length of the expansion element remains unexpanded;   wherein at least two prostheses are positionable on the expandable portion so as to be expanded simultaneously, and wherein at least one of the prostheses may be retained unexpanded on the catheter while at least one other of the prostheses is being expanded.   
   
   
       39 . The catheter system of  claim 38 , wherein the expansion element comprises an inflatable balloon. 
   
   
       40 . The catheter system of  claim 38 , further comprising a sheath axially movable on the catheter body to cover at least a portion of the expansion element and the prostheses. 
   
   
       41 . The catheter system of  claim 40 , wherein the sheath is adapted to constrain expansion of a selected length of the expansion element. 
   
   
       42 . The catheter system of  claim 40 , further comprising a valve member coupled to the sheath and adapted to engage one or more of the prostheses. 
   
   
       43 . The catheter system of  claim 40 , further comprising a pusher axially movable relative to the sheath and adapted to hold the prostheses in position as the sheath is moved. 
   
   
       44 . The catheter system of  claim 43 , wherein the pusher may be selectively coupled and uncoupled with the sheath so as to move axially therewith or to stay fixed as the sheath moves. 
   
   
       45 . The catheter system of  claim 38 , wherein the prostheses are unconnected to each other prior to deployment. 
   
   
       46 . The catheter system of  claim 38 , wherein the expansion element has a length at least as long as the combined length of two of the prostheses. 
   
   
       47 . The catheter system of  claim 38 , wherein at least three prostheses are carried by the catheter. 
   
   
       48 . The catheter system of  claim 47 , wherein the expandable portion of the expansion element has a maximum length at least as long as the combined length of all of the prostheses in the catheter. 
   
   
       49 . The catheter system of  claim 38 , wherein the prostheses comprise vascular stents. 
   
   
       50 . The catheter of  claim 49 , wherein the prostheses carry a therapeutic agent. 
   
   
       51 . The catheter system of  claim 50 , wherein the therapeutic agent inhibits hyperplasia. 
   
   
       52 . The catheter system of  claim 50 , wherein the therapeutic agent is disposed in a bioresorbable material formed on or within the prostheses. 
   
   
       53 . A catheter system as in  claim 52 , wherein the bioresorbable material is selected from the group consisting of polyethylene glycol, collagen, gelatin polyglycolic acids, and polylactic acids. 
   
   
       54 . The catheter system of  claim 52 , wherein the bioresorbable material is coated on the prosthesis. 
   
   
       55 . The catheter system of  claim 38 , wherein the prostheses are adapted to expand such that adjacent ends of thereof are no more than about 1 mm apart. 
   
   
       56 . The catheter system of  claim 38 , wherein following expansion in the body lumen the prostheses are substantially free of material extending between adjacent prostheses.