Advanced endovascular graft and delivery system

Abstract

Embodiments are directed in part to endovascular prostheses and methods of deploying same. Embodiments may be directed more specifically to stent grafts and methods of positioning and deploying such devices within the body of a patient.

1 . A stent graft comprising:
 a graft body comprising a flexible tubular main body having an inner lumen configured to confine a flow of fluid therethrough and a graft collar disposed at a proximal end of the main body; and   a stent including a distal stent portion which is disposed distally of a proximal edge of the graft collar and which is at least partially secured to the graft collar and a proximal stent portion which is disposed proximally of the graft collar, includes at least one barb extending radially outward therefrom and includes an axial length of about 1 mm to about 5 mm.   
     
     
         2 . The stent graft of  claim 1  wherein the distal stent portion comprises an axial length of about 10 mm to about 15 mm. 
     
     
         3 . The stent graft of  claim 2  wherein the proximal stent portion includes a plurality of barbs disposed proximally of a proximal edge of the graft collar. 
     
     
         4 . The stent graft of  claim 1  wherein the entire distal stent portion is secured to graft collar. 
     
     
         5 . The stent graft of  claim 4  wherein the distal stent portion is disposed between adjacent layers of material of the graft collar. 
     
     
         6 . The stent graft of  claim 1  wherein the stent comprises a self-expanding stent. 
     
     
         7 . The stent graft of  claim 6  wherein the self-expanding stent comprises a superelastic alloy. 
     
     
         8 . The stent graft of  claim 7  wherein the superelastic alloy comprises NiTi alloy. 
     
     
         9 . The stent graft of  claim 1  wherein the at least one barb is oriented in a distal direction. 
     
     
         10 . The stent graft of  claim 1  wherein no barbs are disposed more than about 5 mm from the proximal edge of the graft collar. 
     
     
         11 . The stent graft of  claim 1  wherein the distal stent portion comprises a continuous sinusoidal configuration and the at least one barb is disposed on a strut that extends proximally from an apex of a sinusoidal configuration of the distal stent portion. 
     
     
         12 . The stent graft of  claim 1  wherein the distal stent portion comprises a distal portion of a continuous sinusoidal configuration and the at least one barb is disposed on a strut of a proximal portion of the sinusoidal configuration that extends proximally from the proximal edge of the graft collar and forms the proximal stent portion of the stent. 
     
     
         13 . The stent graft of  claim 1  wherein the stent comprises a balloon expandable stent. 
     
     
         14 . The stent graft of  claim 13  wherein the balloon expandable stent comprises a high strength alloy. 
     
     
         15 . The stent graft of  claim 14  wherein the high strength alloy comprises a stainless steel alloy. 
     
     
         16 . The stent graft of  claim 1  wherein the distal stent portion comprises at least one eyelet and the distal stent portion is secured to the graft collar with flap of material disposed through the eyelet and secured to the graft collar. 
     
     
         17 . A method of deploying a stent graft in a patient's vessel, comprising:
 a. providing a stent graft comprising:
 a graft body comprising a flexible tubular main body having an inner lumen configured to confine a flow of fluid therethrough and a graft collar disposed at a proximal end of the main body, and 
 a stent including a distal stent portion which is disposed distally of a proximal edge of the graft collar and which is at least partially secured to the graft collar and a proximal stent portion which is disposed proximally of the graft collar, includes at least one barb extending radially outward therefrom and includes an axial length of about 1 mm to about 5 mm; 
   b. axially positioning the stent graft at a desired site within the patient's vessel with the at least one barb disposed axially coextensive with a viable landing zone of the patient's vessel; and   c. deploying the stent of the stent graft so as to engage the tissue of the viable landing zone of an inner luminal wall of the patient's vessel.   
     
     
         18 . The method of  claim 17  wherein deploying the stent comprises deploying the stent disposed at a proximal end of the stent graft disposed towards a source of blood flow in the patient's vessel. 
     
     
         19 . The method of  claim 17  wherein the stent comprises a self-expanding stent and deploying the stent comprises releasing a radial constraint from the stent in a radially constrained state. 
     
     
         20 . The method of  claim 17  wherein the stent comprises a balloon expandable stent and deploying the stent comprises expanding the stent radially outward with an expandable member disposed within an inner lumen of the stent. 
     
     
         21 . The method of  claim 20  wherein the expandable member comprises an inflatable balloon and deploying the stent comprises expanding the stent radially outward by inflating the inflatable balloon with a source of pressurized fluid. 
     
     
         22 . A delivery system for delivering a stent graft, the delivery system comprising:
 a delivery catheter comprising an elongate shaft with a proximal section and a distal section;   a stent graft having a main graft body with an inner lumen configured for confining a flow of blood therethrough, the stent graft being loaded on the proximal section of the delivery catheter with the elongate shaft disposed within the inner lumen; and   an expandable centering device disposed on the elongate shaft within the inner lumen, the centering device being configured to expand from a radially contracted state to a radially expanded state for centering the elongate shaft and stent graft of the delivery system toward a midline longitudinal axis of a patient's vessel when introduced into the patient's vessel.   
     
     
         23 . The delivery system of  claim 22  wherein said centering device comprises an expanding basket, the basket including elongate tines that extend substantially parallel to the elongate shaft of the delivery catheter in the radially contracted configuration and are configured to bow radially outwardly from the elongate shaft in a substantially concentric arrangement in the radially expanded configuration. 
     
     
         24 . The delivery system of  claim 23  wherein the elongate tines are configured to self-expand to the radially expanded configuration. 
     
     
         25 . The delivery system of  claim 23  wherein the elongate tines are configured to expand to the radially expanded configuration due to axial compressive force applied to at least one end of the tines. 
     
     
         26 . The delivery system of  claim 24  wherein the elongate tines comprise of a self-expanding metal. 
     
     
         27 . The delivery system of  claim 26  wherein the self-expanding metal comprises NiTi alloy. 
     
     
         28 . The delivery system of  claim 24  wherein the elongate tines comprise of a superelastic metal. 
     
     
         29 . The delivery system of  claim 28  wherein the superelastic metal comprises NiTi alloy. 
     
     
         30 . The delivery system of  claim 22  wherein said centering device comprises an inflatable structure including:
 a collapsed deflated state, and 
 an enlarged inflated state with a substantially cylindrical configuration including vias that extend from ports in a proximal surface of the centering device to respective ports in a distal surface of the centering device for continuous flow of blood through the centering device and delivery system during inflation of the centering device and deployment of the stent graft. 
 
     
     
         31 . The delivery system of  claim 30  wherein the expandable vias have a cumulative cross section that is at least about 5 percent to about 10 percent of the total cross section of the centering device in an expanded state. 
     
     
         32 . The delivery system of  claim 30  wherein the expandable centering device comprises a configuration that is radially concentric with the elongate shaft in the enlarged inflated state. 
     
     
         33 . The delivery system of  claim 22  wherein the centering device has an outer transverse dimension of about 50 mm to about 80 mm in the radially expanded state. 
     
     
         34 . The delivery system of  claim 22  wherein the centering device is configured to expand to an outer transverse dimension that is at least as large as an inner transverse dimension of the inner lumen of the patient's vessel. 
     
     
         35 . A method of centering a delivery system during deployment of a stent graft, comprising:
 a. providing a delivery system for delivering a stent graft, the delivery system comprising:
 a delivery catheter comprising an elongate shaft with a proximal section and a distal section, 
 a stent graft having a main graft body with an inner lumen configured for confining a flow of blood therethrough and a stent secured to the main graft body, the stent graft being loaded on the proximal section of the delivery catheter with the elongate shaft disposed within the inner lumen, and 
 an expandable centering device disposed on the elongate shaft within the inner lumen, the centering device being configured to expand from a radially contracted state to a radially expanded state for centering the elongate shaft and stent graft of the delivery system toward a midline longitudinal axis of a patient's vessel when introduced into the patient's vessel; 
   b. positioning the delivery catheter within a patient's vessel such that the stent graft is axially positioned at a desired site within the patient's vessel with the expandable centering device in the radially contracted state;   c. expanding the expandable centering device to the radially expanded state to center the elongate shaft and stent graft of the delivery system toward the longitudinal axis of the patient's vessel; and   d. deploying the stent of the stent graft so as to engage an inner luminal wall of the patient's vessel.   
     
     
         36 . The method of  claim 35  wherein deploying the stent comprises deploying a stent disposed at a proximal end of the stent graft disposed towards a source of blood flow in the patient's vessel. 
     
     
         37 . The method of  claim 35  wherein the expandable centering device comprises a basket and wherein expanding the expandable centering device comprises allowing self-expanding elongate tines of the basket to self-expand to the radially expanded state. 
     
     
         38 . The method of  claim 35  wherein the expandable centering device comprises a basket and wherein expanding the expandable centering device comprises axially compressing at least one end of elongate tines of the basket to shorten a separation of the proximal ends and distal ends of the elongate tines of the basket and expand a center portion of the tines to the radially expanded state. 
     
     
         39 . The method of  claim 35  wherein the expandable centering device comprises an inflatable structure and wherein expanding the expandable centering device comprises inflating an interior volume of the inflatable structure with a biocompatible fluid to expand the inflatable structure to the radially expanded state. 
     
     
         40 . The method of  claim 39  wherein the interior volume of the inflatable structure is inflated through an inflation lumen with a fluid from a source of pressurized fluid. 
     
     
         41 . The method of  claim 40  wherein the source of pressurized fluid comprises a syringe and inflating the interior volume of the inflatable structure comprises injecting fluid from an interior volume of the syringe through the inflation lumen and into the interior volume of the inflatable structure. 
     
     
         42 . The method of  claim 39  wherein the biocompatible fluid comprises saline solution and inflating an interior volume of the inflatable structure comprises inflating the interior volume with saline solution. 
     
     
         43 . The method of  claim 35  wherein expanding the expandable centering device to the radially expanded state to center the elongate shaft and stent graft of the delivery system toward the longitudinal axis of the patient's vessel comprises expanding the expandable centering device to an outer transverse dimension which is about the same as a transverse dimension of an inner lumen of the patient's vessel at a position of the expandable centering device. 
     
     
         44 . A delivery system for delivering a stent graft, the delivery system comprising:
 (1) a delivery catheter comprising an elongate shaft with a proximal section and a distal section;   (2) a releasable stent constraint system disposed on the proximal section elongate shaft, the stent constraint system comprising:
 (a) a crown constraint sleeve including a rigid tubular structure disposed about the elongate shaft with a plurality of crown restraint extensions extending distally from the crown constraint sleeve, the crown restraint extensions being circumferentially spaced from each other, and 
 (b) a strut support assembly which is slidingly disposed about the elongate shaft distally adjacent the crown constraint sleeve, and which includes a plurality of strut supports which are circumferentially aligned with respective crown restraint extensions of the crown constraint sleeve and which extend radially away from a longitudinal axis of the elongate shaft, 
 (c) a docked state wherein the strut supports form openable crown constraint passages between the strut supports and respective crown constraint extensions of the crown constraint sleeve, and 
 (d) an open state wherein the strut support assembly is spaced axially away from the crown constraint sleeve and the crown restraint passages are opened to allow radial expansion of stent crowns disposed therein; and 
   (3) a stent graft including a self-expanding stent secured to a proximal end of a main graft body, the main graft body having an inner lumen configured for confining a flow of blood therethrough, the stent graft being loaded on the proximal section of the delivery catheter with the elongate shaft disposed within the inner lumen and a plurality of proximal stent crowns disposed within closed crown restraint passages of the stent constraint system with the strut support assembly in a docket state.   
     
     
         45 . The delivery system of  claim 44  wherein the crown constraint sleeve is secured to elongate shaft and the strut support assembly is slidingly disposed about elongate shaft distally adjacent the crown constraint sleeve. 
     
     
         46 . The delivery system of  claim 45  wherein the strut support assembly is resiliently biased towards the crown constraint sleeve in an axial direction. 
     
     
         47 . The delivery system of  claim 46  wherein the strut support assembly is resiliently biased towards the crown constraint sleeve in an axial direction by an axially oriented spring disposed between the strut support assembly and the elongate shaft. 
     
     
         48 . The delivery system of  claim 44  wherein the strut support assembly is secured to the elongate shaft and the crown constraint sleeve is slidingly disposed about elongate shaft proximally adjacent the crown constraint sleeve. 
     
     
         49 . The delivery system of  claim 44  further comprising at least one releasable belt disposed about the stent of the stent graft. 
     
     
         50 . The delivery system of  claim 49  wherein the at least one releasable belt is locked in a constrained configuration about the stent with a removable trigger wire. 
     
     
         51 . A method of deploying a stent graft, comprising:
 providing a delivery system for delivering a stent graft, the delivery system comprising:
 (1) a delivery catheter comprising an elongate shaft with a proximal section and a distal section; 
 (2) a releasable stent constraint system disposed on the proximal section elongate shaft, the stent constraint system comprising:
 (a) a crown constraint sleeve including a rigid tubular structure disposed about the elongate shaft with a plurality of crown restraint extensions extending distally from the crown constraint sleeve, the crown restraint extensions being circumferentially spaced from each other, 
 (b) a strut support assembly which is disposed about the elongate shaft distally adjacent the crown constraint sleeve, and which includes a plurality of strut supports which are circumferentially aligned with respective crown restraint extensions of the crown constraint sleeve and which extend radially away from a longitudinal axis of the elongate shaft, 
 (c) a docked state wherein the strut supports form openable crown constraint passages between the strut supports and respective crown constraint extensions of the crown constraint sleeve, and 
 (d) an open state wherein the strut support assembly is spaced axially away from the crown constraint sleeve and the crown restraint passages are opened to allow radial expansion of stent crowns disposed therein; and 
 
 (3) a stent graft including a self-expanding stent secured to a proximal end of a main graft body, the main graft body having an inner lumen configured for confining a flow of blood therethrough, the stent graft being loaded on the proximal section of the elongate shaft with the elongate shaft disposed within the inner lumen and a plurality of proximal stent crowns disposed within closed crown restraint passages of the stent constraint system with the strut support assembly in a docket state; 
   axially positioning the stent graft at a desired site within the patient's vessel; and   axially separating the crown restraint sleeve from the strut support assembly so as to open the crown restraint passages allowing crowns of the stent contained within the crown restraint passages to radially expand.   
     
     
         52 . The method of  claim 51  wherein the crown constraint sleeve is secured to elongate shaft and the strut support assembly is slidingly disposed about elongate shaft distally adjacent the crown constraint sleeve and wherein axially separating the crown restraint sleeve from the strut support assembly so as to open the crown restraint passages allowing crowns of the stent contained within the crown restraint passages to radially expand comprises displacing the strut support assembly in an axial direction relative to the crown constraint sleeve and the elongate shaft. 
     
     
         53 . The method of  claim 52  wherein the strut support assembly is resiliently biased towards the crown constraint sleeve in an axial direction and displacing the strut support assembly in an axial direction relative to the crown constraint sleeve and the elongate shaft comprises retracting the strut support assembly applying axial displacement in a distal direction on a pull rod that is secured to the strut support assembly and extends distally to a distal end of the elongate shaft. 
     
     
         54 . The method of  claim 51  wherein the strut support assembly is secured to the elongate shaft and the crown constraint sleeve is slidingly disposed about elongate shaft proximally adjacent the crown constraint sleeve and wherein axially separating the crown restraint sleeve from the strut support assembly so as to open the crown restraint passages allowing crowns of the stent contained within the crown restraint passages comprises displacing the crown constraint sleeve in a proximal direction relative to the strut support assembly and the elongate shaft. 
     
     
         55 . The method of  claim 54  wherein the crown constraint sleeve is resiliently biased towards the strut support assembly in an axial direction and displacing the crown constraint sleeve in an axial direction relative to the strut support assembly and the elongate shaft comprises displacing the crown constraint sleeve by applying axial displacement in a proximal direction on a push rod that is secured to the crown constraint sleeve and extends distally to a distal end of the elongate shaft. 
     
     
         56 . The method of  claim 51  wherein the stent constraint system further comprises at least one releasable belt disposed about and constraining the stent of the stent graft and further comprising releasing the releasable belt to at least partially deploy the stent. 
     
     
         57 . The method of  claim 56  wherein the at least one releasable belt is locked in a constrained configuration about the stent with a removable trigger wire and wherein releasing the releasable belt comprises withdrawing the trigger wire from the releasable belt. 
     
     
         58 . A delivery system for delivering a stent graft, the delivery system comprising:
 (1) a delivery catheter comprising an elongate shaft with a proximal section and a distal section;   (2) a releasable stent constraint system disposed on the proximal section elongate shaft, the stent constraint system comprising:
 (a) a stent constraint sleeve which includes a rigid tubular structure slidably disposed about the elongate shaft between a distal position and a proximal position and which includes a plurality of crown sections that extend distally from the crown constraint sleeve and that are circumferentially spaced from each other, 
 (b) a plurality of strut supports which are secured to the elongate shaft distally adjacent the stent constraint sleeve, which are circumferentially spaced from each other and which extend radially away from a longitudinal axis of the elongate shaft, 
 (c) a constraint state wherein the stent constraint sleeve is disposed in the distal position, and 
 (d) a deployment state wherein the stent constraint sleeve is in the proximal position; 
   (3) an expandable basket including a plurality of elongate tines which are disposed in a substantially tubular configuration, which extend axially along the elongate shaft of the delivery catheter in a position distally adjacent the stent constraint sleeve, and which are configured to bow radially outward upon reduction of a separation between proximal ends of the elongate tines and distal ends of the elongate tines; and   (4) a stent graft including:
 (a) a flexible main graft body having an inner lumen configured for confining a flow of blood therethrough, a proximal end and a distal end, and 
 (b) a self-expanding stent with a proximal end, a distal end secured to the proximal end of the main graft body, a plurality of proximal stent crowns which include at least one barb; and 
   wherein the stent graft is loaded on the proximal section of the elongate shaft with the elongate shaft disposed within the inner lumen, the plurality of proximal stent crowns which include at least one barb are disposed within and radially constrained by the stent constraint sleeve with the stent constraint sleeve in the distal position, and with at least one elongate tine of the expandable basket disposed beneath a stent crown that includes a barb, the at least one elongate tine being configured to apply outward radial force on the stent crown upon deployment of the stent and expansion of the expandable basket.   
     
     
         59 . The system of  claim 58  wherein the delivery system further comprises a lock member which is axially fixed relative to the elongate shaft, which engages a first hole in the stent constraint sleeve when the stent constraint sleeve is in the distal position, which engages a second hole disposed distally of the first hole when the stent constraint sleeve is in a proximal position. 
     
     
         60 . A method of deploying a stent graft, comprising:
 (A) providing a delivery system for delivering a stent graft, the delivery system comprising:
 (1) a delivery catheter comprising an elongate shaft with a proximal section and a distal section; 
 (2) a releasable stent constraint system disposed on the proximal section elongate shaft, the stent constraint system comprising:
 (a) a stent constraint sleeve which includes a rigid tubular structure slidably disposed about the elongate shaft between a distal position and a proximal position and which includes a plurality of crown sections that extend distally from the crown constraint sleeve and that are circumferentially spaced from each other, 
 (b) a plurality of strut supports which are secured to the elongate shaft distally adjacent the stent constraint sleeve, which are circumferentially spaced from each other and which extend radially away from a longitudinal axis of the elongate shaft, 
 (c) a constraint state wherein the stent constraint sleeve is disposed in the distal position, and 
 (d) a deployment state wherein the stent constraint sleeve is in the proximal position; 
 
   (3) an expandable basket including a plurality of elongate tines which are disposed in a substantially tubular configuration, which extend axially along the elongate shaft of the delivery catheter in a position distally adjacent the stent constraint sleeve, and which are configured to bow radially outward upon reduction of a separation between proximal ends of the elongate tines and distal ends of the elongate tines; and   (4) a stent graft including:
 (a) a flexible main graft body having an inner lumen configured for confining a flow of blood therethrough, a proximal end and a distal end, and 
 (b) a self-expanding stent with a proximal end, a distal end secured to the proximal end of the main graft body, a plurality of proximal stent crowns which include at least one barb; and 
   wherein the stent graft is loaded on the proximal section of the elongate shaft with the elongate shaft disposed within the inner lumen, the plurality of proximal stent crowns which include at least one barb are disposed within and radially constrained by the stent constraint sleeve with the stent constraint sleeve in the distal position, and with at least one elongate tine of the expandable basket disposed beneath a stent crown that includes a barb, the at least one elongate tine being configured to apply outward radial force on the stent crown upon deployment of the stent and expansion of the expandable basket;   (B) axially positioning the stent graft at a desired site within the patient's vessel;   (C) axially displacing the stent constraint sleeve in a proximal direction from the distal position to the proximal position to release the crowns of the stent to radially expand; and   (D) radially expanding the expandable basket such that at least one elongate tine of the expandable basket which is disposed beneath a corresponding crown having a barb extends radially outward and applies an outward radial force to the corresponding crown so as to facilitate engagement of the barb with tissue of the patient's vessel at the desired site.   
     
     
         61 . The method of  claim 60  wherein the delivery system further comprises a lock member which is axially fixed relative to the elongate shaft, which engages a first hole in the stent constraint sleeve when the stent constraint sleeve is in the distal position, which engages a second hole disposed distally of the first hole when the stent constraint sleeve is in a proximal position and wherein axially displacing the stent constraint sleeve in a proximal direction from the distal position to the proximal position comprises disengaging the lock from the first hole and engaging the lock in the second hole.