Delivery system for a self expanding stent

Abstract

A system for delivering a stent from a catheter sheath in a longitudinal direction comprising: a thumbwheel mounted on an axle, the axle being supported by opposite walls of a housing; a first pinion mounted on the axle; a second pinion mounted on the axle, whereby rotation of the thumbwheel causes rotation of the first pinion and rotation of the second pinion; a first rack, engageable with the first pinion at a first surface of the first pinion, the first rack being operably connected with a stent-engaging member; a second rack, engageable with the second pinion at a second surface of the second pinion, the second surface being disposed in a direction diametrically opposite the first surface, the second rack being operably connected with a sheath configured to confine the stent.

I claim: 
     
         1 . A system for delivering a stent comprising:
 a handle having a housing with a cavity defined therein;   a thumbwheel rotatably coupled to the housing by an axle and disposed with at least a portion of the thumbwheel exposed external to the housing;   a first pinion and a second pinion disposed within the cavity and mounted on the axle to rotate with the thumbwheel;   a first rack and a second rack disposed within the cavity and axially moveably relative each other, the first rack in engagement with the first pinion to move axially in a first direction by rotation of the thumbwheel in a first rotational direction and the second rack in engagement with the second pinion to simultaneously move axially in a second direction by the rotation of the thumbwheel in the first rotational direction;   an outer sheath operatively coupled to the first rack to be displaced in the first direction a first distance “Y” by the rotation of the thumbwheel;   a self-expanding stent disposed within an inner lumen of the outer sheath, the stent having a delivery condition with delivery condition length “L 1 ” when disposed within the outer sheath and a deployed condition with a deployed condition length “L 2 ”; and   a stent engagement member disposed within an inner lumen of the stent and operatively connected to the second rack to be displaced in the second direction a second distance “X” by the rotation of the thumbwheel,   wherein a ratio of the distances X:Y maintains a distal end of the stent at an initial location “P” during deployment.   
     
     
         2 . The system of  claim 1 , wherein the thumbwheel has a diameter greater than a diameter of either of the first and second pinions. 
     
     
         3 . The system of  claim 1 , wherein the first pinion is disposed on a first side of the thumbwheel and the second pinion is disposed on a second side of the thumbwheel. 
     
     
         4 . The system of  claim 3 , wherein the first side and second side are on opposing sides of the thumbwheel. 
     
     
         5 . The system of  claim 1 , wherein the first direction and the second direction are opposite directions. 
     
     
         6 . The system of  claim 1 , wherein the first rack is in engagement with a perimeter of the first pinion at a first engagement location and the second rack is in engagement with a perimeter of the second pinion at a second engagement location, the first engagement location being diametrically opposite the second engagement location. 
     
     
         7 . The system of  claim 6 , wherein the portion of the thumbwheel exposed external to the housing is proximate the first rack. 
     
     
         8 . The system of  claim 1 , wherein the first rack is disposed on a first side of the thumbwheel and the second rack is disposed on a second side of the thumbwheel. 
     
     
         9 . The system of  claim 1 , wherein the initial location P is defined by the location of the distal end of the stent upon initiation of deployment by rotation of the thumbwheel. 
     
     
         10 . The system of  claim 1 , wherein the initial location P is defined by the location of the distal end of the stent upon initiation of displacement of the outer sheath in the first direction. 
     
     
         11 . The system of  claim 1 , wherein an initial distance “D” is defined between the initial location P and a distal end of the handle. 
     
     
         12 . The system of  claim 1 , wherein the ratio of distances X:Y maintains the initial distance D during deployment. 
     
     
         13 . The system of  claim 1 , wherein the ratio of the distances X:Y is equal to the ratio of the difference of the delivery condition length and the deployed condition length (“L 1 −L 2 ”) to the deployed condition length L 2 . 
     
     
         14 . The system of  claim 1 , wherein the first pinion has a first diameter and the second pinion has a second diameter, and further wherein a ratio of the first diameter to the second diameter maintains a distal end of the stent at the initial location P during deployment. 
     
     
         15 . The system of  claim 14 , wherein the ratio of the second pinion diameter to the first pinion diameter is equal to the ratio of the difference of the delivery condition length and the deployed condition length (“L 1 −L 2 ”) to the deployed condition length L 2 . 
     
     
         16 . The system of  claim 14 , wherein the ratio of the distances X:Y is equal to the ratio of the second pinion diameter to the first pinion diameter. 
     
     
         17 . The system of  claim 1 , wherein the stent comprises a braided material, the stent engagement member configured to engage the stent within the braided material when moved in the second direction.