Delivery System for A Self-Expanding Device for Placement in a Bodily Lumen

Abstract

A delivery system ( 114 ) for a self-expanding device ( 110 ) for placement in a bodily lumen, the system comprising a sheath ( 112 ) that confines the device to a radially compact delivery disposition until the device is to be released into the lumen, the system having an elongate pull element ( 118 ) to be pulled proximally from its proximal end, which pull element is arranged radially inside the sheath for pulling preferentially on a pull zone on the circumference of the distal end of the sheath, thereby to tear the sheath progressively along a tear line running the length of the sheath, starting at the distal end of the sheath, to release the device from the confining effect of the sheath, progressively, beginning at the distal end of the device and wherein the sheath is of polyethylene-terephthalate, cold drawn along its long axis, and in that the distal end of the sheath tapers inwardly to provide an inwardly tapered distal end of the system.

1 . A system comprising:
 a vascular body having a distal body region;   a vascularly implantable medical device;   a sheath having:
 a pull region on a circumference of a distal end of the sheath; 
 a lengthwise wall that has a first perforated line adjacent the pull region and a second perforated line separated from the first perforated; 
   a first pull element having proximal and distal ends with the distal end connecting to the sheath adjacent the pull region;   a second pull element having proximal and distal ends with the distal end connecting to the sheath adjacent the pull region;   and   wherein the proximal end of the first pull elements extends or connects to a pull wire that extends from the distal end of the sheath between the medical device and the sheath and that emerges from a proximal end of the sheath.   
     
     
         2 . The system of  claim 1  further comprising:
 an undulating portion having a distal end connected to the proximal end of the second pull element; 
 and 
 a coupling mechanism positioned coaxially around the body and connected to the proximal end of the first pull element, to the proximal end of the undulating portion, and to the distal end of the pull wire. 
 
     
     
         3 . The system of  claim 2  wherein the coupling mechanism is disposed proximal of the sheath. 
     
     
         4 . The system of  claim 3  in which the first perforated line defines a first line of weakness and the distal end of the first line defines a tear initiation point on the sheath. 
     
     
         5 . The system of  claim 4  in which the second perforated line defines a second line of weakness and the distal end of the second line defines a second tear initiation point on the sheath. 
     
     
         6 . The system of  claim 5  in which either or both tear initiation points comprise a notch or slit. 
     
     
         7 . The system of  claim 6  in which either or both pull elements and the sheath are monolithic. 
     
     
         8 . The system of  claim 7  in which the device is a self-expanding stent or self-expanding stent graft. 
     
     
         9 . The system of  claim 8  in which the coupling mechanism is radiopaque. 
     
     
         10 . The system of  claim 9  in which the device comprises a shape memory alloy comprising nickel and titanium. 
     
     
         11 . The system of  claim 10  wherein the coupling mechanism is disposed proximal of the sheath. 
     
     
         12 . The system of  claim 11  in which the first perforated line defines a first line of weakness and the distal end of the first line defines a tear initiation point on the sheath. 
     
     
         13 . The system of  claim 12  in which the second perforated line defines a second line of weakness and the distal end of the second line defines a second tear initiation point on the sheath. 
     
     
         14 . The system of  claim 13  in which either or both tear initiation points comprise a notch or slit. 
     
     
         15 . The system of  claim 14  in which either or both pull elements and the sheath are monolithic. 
     
     
         16 . The system of  claim 15  in which the device is a self-expanding stent or self-expanding stent graft. 
     
     
         17 . The system of  claim 16  in which the coupling mechanism is radiopaque. 
     
     
         18 . The system of  claim 17  in which the device comprises a shape memory alloy comprising nickel and titanium.