System and method for endoluminal grafting of bifurcated and branched vessels

Abstract

A system and method for endoluminal grafting of a main anatomic conduit in its diseased state in which it dilates to pose a life threatening condition and its various conduits that emanate from the main anatomic conduit. The grafting system comprises an endoaortic graft having at least one opening therein and at least one branch graft that is passable through the opening of the endoaortic graft into the branch anatomic conduit(s) such that the junction between the branch graft and the endoaortic graft is substantially fluid tight. A system and method for delivery of the endoaortic graft and also a system and method for efficient alignment and deployment of the branch (e.g., side branch) graft such that the coupling of the branch graft with the endoaortic graft is efficient and exact and fluid-tight; and a system and method for coupling the branch to the endoaortic graft via a coupling mechanism employing a memory metal alloy; a system and method for the proper and exact alignment of the endoaortic graft and the branch using magnetic force of a suitable nature, and which does not use the magnetic force as the coupling mechanism.

1 . A system for endoluminal grafting of a native, main anatomic conduit, in a region where at least one branch anatomic conduit extends from the main anatomic conduit, comprising:
 an endoaortic graft including a first pliable tube having a lumen extending longitudinally therefrom, at least one branch opening formed in the first pliable tube, and endoaortic graft anchoring means for holding the first pliable tube in substantially fixed place within the main anatomic conduit with the branch opening in alignment with the branch anatomic conduit, the first pliable tube being made of a biocompatible material;   a branch graft including a second pliable tube having a proximal end, a mid-portion, a distal end, a lumen extending therethrough, and branch graft anchoring means at the distal end for holding at least the distal end of the branch graft in contact with the surrounding wall of the branch anatomic conduit, the second pliable tube being made of a biocompatible material, the second pliable tube being sized to be receivable through the branch opening such that a junction between the endoaortric branch and the branch graft is substantially fluid tight;   selectively activatable connector means for connecting the proximal end of the second pliable tube with the branch opening of the first pliable tube upon activation to allow the fluid that flows through the lumen of the endoaortic graft to pass through the branch opening into the lumen of the branch graft, wherein the connector means includes a portion made from memory metal for effecting a mechanical, non-magnetic connection between the proximal end of the second pliable tube and the branch opening of the first pliable tube;   endoaortic graft delivery means for introducing the first pliable tube into the anatomic conduit; and   branch graft delivery means for housing the second pliable tube and introducing it into the branch anatomic conduit.   
     
     
         2 . The system of  claim 1 , wherein the endoaortic graft delivery means includes:
 an outer sheath;   an inner central sheath substantially concentric with the outer sheath for carrying an axial guide wire;   at least one inner side sheath radially positioned between the inner central sheath and a corresponding branch opening for carrying the separate branch anatomic conduit guide wire, the first pliable tube being loaded in the endoaortic graft delivery means such that the branch anatomic conduit guide wire carried by the at least one inner side sheath to the branch anatomic conduit traverses through the corresponding at least one branch opening; and   a tapered and flexible tip at the distal end of the inner central sheath, the tip forming the nose cone of the endoaortic graft delivery means and having apertures, one of which allows the passage of the axial guide wire therethrough.   
     
     
         3 . The system of  claim 2 , further comprising at least one separate branch anatomic conduit guide wire that is to be passed into a corresponding side branch anatomic conduit, the at least one branch anatomic conduit guide wire being positioned in a corresponding inner side sheath for passage through one of the apertures in the tip of the branch graft delivery means. 
     
     
         4 . The system of  claim 1 , wherein the mid-portion of the second pliable tube includes means for maintaining a patent lumen therein such that the branch graft is kink resistant in an angular situation. 
     
     
         5 . The system of  claim 1 , wherein the endoaortic graft anchoring means comprises at least one of a radially expandable stent, a frame, hooks, rings, sutures, staples, adhesive, and staples. 
     
     
         6 . The system of  claim 1 , wherein the connector means includes a material having sufficient magnetic properties to be attracted to the flexible magnetic ring yet still be easily movable relative thereto. 
     
     
         7 . The system of  claim 1 , wherein the endoaortic graft further includes a flexible magnetic ring positioned around the at least one branch opening of the first pliable tube, and wherein the branch graft delivery means includes:
 a hollow outer sheath, the outer sheath being non-retractable and carrying a magnet at its distal end;   a hollow inner sheath concentric with the outer sheath, and   a hollow middle sheath concentric with and positioned between the outer and inner sheaths, the branch graft being housed between the inner sheath and the middle sheath, at least a portion of the middle sheath covering the branch graft;   a tapered and flexible tip at the distal end of the inner central sheath, the tip forming the nose cone of the branch graft delivery means;   whereby when the middle sheath is retracted, it will uncover the branch graft such that the branch graft is deployed fully to form a connection with the endoaortic graft.   
     
     
         8 . The system of  claim 7 , wherein the magnetic ring is selected from the group consisting of an electromagnet, a ferromagnet, and a ferromagnetic fluid. 
     
     
         9 . The system of  claim 7 , wherein the flexible magnetic ring is positioned on the exterior surface of the first pliable tube. 
     
     
         10 . The system of  claim 9 , wherein the flexible magnetic ring is permanently secured to the exterior surface of the first pliable tube. 
     
     
         11 . The system of  claim 7 , wherein the flexible magnetic ring is positioned on the interior surface of the first pliable tube. 
     
     
         12 . The system of  claim 11 , wherein the flexible magnetic ring is removably secured to the interior surface of the first pliable tube. 
     
     
         13 . The system of  claim 7 , wherein the magnet of the branch graft delivery means has a natural magnetic field. 
     
     
         14 . The system of  claim 7 , wherein the magnet of the branch graft delivery means has an induced magnetic field. 
     
     
         15 . The system of  claim 7 , wherein the magnet of the branch graft delivery means is chosen from the group consisting of an electromagnet, a ferromagnet, and a ferromagnetic fluid. 
     
     
         16 . The system of  claim 7 , wherein the outer sheath is rotatable so as to change the polarity of the magnet in a particular plane. 
     
     
         17 . The system of  claim 7 , wherein prior to deployment, the distal ends of the inner and middle sheaths are substantially coterminous, and the middle sheath covers substantially the entire length of the branch graft. 
     
     
         18 . The system of  claim 7 , wherein prior to deployment, the distal end of the inner sheath extends outwardly of the distal ends of the middle and outer sheaths, with the branch graft loaded over the distal end of the middle sheath with only the connector means housed between the middle and outer sheaths, and wherein the branch graft delivery system includes means for maintaining the branch graft in a contracted condition prior to deployment. 
     
     
         19 . The system of  claim 18 , wherein the means for maintaining the branch graft in a contracted position includes a deployment wire radially positioned between the inner and middle sheaths, and a thread wrapped around both the contracted branch graft and the deployment wire in a figure-8 configuration, whereby when the deployment wire is retracted, the wrapping unravels, allowing the branch graft to assume an expanded condition. 
     
     
         20 . The system of  claim 19 , wherein the thread is made of a biodegradable, absorbable material. 
     
     
         21 . A method for endoluminal grafting of a native, main anatomic conduit and a branch anatomic conduit extending from the main anatomic conduit, in a region where at least one branch anatomic conduits extends from the main anatomic conduit, using an endoaortic graft including a first pliable tube having a lumen extending longitudinally therefrom, at least one branch opening formed in the first pliable tube, a flexible magnetic ring positioned around the at least one branch opening of the first pliable tube, and endoaortic graft anchoring means for holding the first pliable tube in substantially fixed place within the main anatomic conduit with the branch opening in alignment with the branch anatomic conduit, the first pliable tube being made of a biocompatible material; and a branch graft including a second pliable tube having a proximal end, a mid-portion, a distal end, a lumen extending therethrough, connector means for connecting the proximal end with the branch opening of the first pliable tube to allow the fluid that flows through the lumen of the endoaortic graft to pass through the branch opening into the lumen of the branch graft, and anchoring means at the distal end for holding at least the distal end of the branch graft in contact with the surrounding wall of the branch anatomic conduit, the second pliable tube being made of a biocompatible material, the method comprising the steps of:
 advancing an axial guide wire into the body of an aneurysm, and then advancing a second, more pliable balloon tipped guide wire into the branch anatomic conduit;   transluminally advancing the endoaortic graft over the guide wires into the branch anatomic conduit;   positioning the endoaortic graft within the main anatomic conduit such that the branch opening is aligned with the branch anatomic conduit;   utilizing the endoaortic graft anchoring means to anchor the endoaortic graft within the main anatomic conduit;   transluminally advancing the branch graft loaded in a retractable sheath of a branch graft delivery system over the guide wire to the branch anatomic conduit, the branch graft delivery system including a magnetic ring at its distal end;   passing the distal end of the branch graft delivery system containing the branch graft through the branch opening and into the branch anatomic conduit, until the magnetic ring of the endoaortic graft and the magnetic ring on the branch delivery system attach;   operating the branch graft delivery system such that the branch graft is deployed in the branch anatomic conduit, until such time that the retractable sheath of the delivery system is fully retracted; and   once the retractable sheath of the branch graft delivery system is fully retracted, rotating the outer sheath of the branch graft delivery system by 180 degrees to switch the magnetic poles to allow the two magnetic rings to disengage.   
     
     
         22 . The method of  claim 21 , wherein in said step of rotating the outer sheath, the most proximal part of the connector means is deployed, allowing the leak proof connection between the branch graft and the endoaortic graft. 
     
     
         23 . The method of  claim 21 , further comprising the steps of:
 withdrawing the branch graft delivery system after said step of rotating the outer sheath;   advancing another guidewire through the lumen of the endoaortic graft;   activating the connector means of the endoaortic graft to engage the proximal end of the branch graft.   
     
     
         24 . The method of  claim 21 , further comprising the step of removing the flexible magnetic ring of the endoaortic graft.