Super elastic, bioabsorbable endovascular devices

Abstract

The invention relates to endovascular medical implant devices and materials of composition for forming these devices to provide improved mechanical properties and biodegradability. The devices include a combination or integration of superelastic material, biodegradable metal and, thin film nitinol and/or biodegradable polymer. A structural frame is formed of individual elongated pieces composed of biodegradable metal. These pieces are joined together by connector pieces composed of superelastic material. At least a portion of the structural frame has deposited thereon the thin film nitinol and/or biodegradable polymer. The structural frame of the device is collapsible for insertion in a delivery tube and, recoverable for deployment and placement in a vascular location of a patient body.

What is claimed is: 
     
         1 . An endovascular medical implant device, comprising:
 a structural frame, elastically deformable from an original structure to a collapsed structure, comprising:
 a plurality of elongated segments composed of biodegradable metal, 
   wherein the biodegradable metal constitutes about 80% or greater of the total mass of the device;
 one or more connectors composed of nitinol structured to join together the plurality of elongated segments, 
   wherein a total of the nitinol constitutes about 10% or less of the total mass of the device; and
 a material comprising biodegradable polymer applied to at least a portion of the structural frame, 
   wherein the biodegradable polymer constitutes about 10% or less of the total mass of the device, and   wherein one or more pairs of the plurality of elongated segments are connected together by the one or more connectors to form the structural frame.   
     
     
         2 . The endovascular medical implant device of  claim 1 , wherein the biodegradable metal is a metal wire. 
     
     
         3 . The endovascular medical implant device of  claim 1 , wherein the biodegradable polymer is in a form selected from the group consisting of coating, sheet and combinations thereof. 
     
     
         4 . The endovascular medical implant device of  claim 3 , wherein the coating comprises electrospun fibers. 
     
     
         5 . The endovascular medical implant device of  claim 1 , wherein the one or more connectors is in a form selected from the group consisting of strut, wire, tube and combinations thereof. 
     
     
         6 . The endovascular medical implant device of  claim 1 , further comprising a mechanism to apply the one or more connectors to the plurality of elongated segments, the mechanism selected from the group consisting of mechanical clamps, adhesive, sutures, micro-laser welding and combinations thereof. 
     
     
         7 . The endovascular medical implant device of  claim 1 , wherein the collapsed structure is placed in a delivery tube, the collapsed structure is configured to be deployed from the delivery tube into a patient body and upon being deployed, the collapsed structure recovers the original structure. 
     
     
         8 . A method of preparing an endovascular device, comprising:
 forming a structural frame, comprising:
 obtaining a plurality of elongated segments composed of biodegradable metal; 
 obtaining one or more connectors composed of nitinol; 
 employing the one or more connectors to join together the plurality of elongated segments to form the structural frame; and 
   applying a biodegradable polymer to at least a portion of the structural frame,   wherein the biodegradable metal constitutes about 80% or greater of the total mass of the device,   wherein a total of the nitinol constitutes about 10% or less of the total mass of the device,   wherein the biodegradable polymer constitutes about 10% or less of the total mass of the device, and   wherein one or more pairs of the plurality of elongated segments are connected together by the one or more connectors to form the structural frame.   
     
     
         9 . The method of  claim 8 , wherein the applying the biodegradable polymer is selected from applying a biodegradable polymer membrane to a backbone of the structural frame, and depositing a biodegradable polymer coating on the plurality of elongated segments. 
     
     
         10 . The method of  claim 8 , further comprising:
 collapsing the structural frame from an original form to a collapsed structure;   inserting the collapsed structure in a delivery tube;   deploying the collapsed structure from the delivery tube into a vascular target in a patient body; and   recovering the original form of the structural frame in the vascular target.   
     
     
         11 . The method of  claim 8 , wherein the employing the one or more connectors to join together the plurality of elongated segments to form the structural frame comprises using a mechanism selected from the group consisting of mechanical clamps, adhesives, sutures, and micro-laser welding. 
     
     
         12 . The method of  claim 8 , wherein the biodegradable metal is a metal wire. 
     
     
         13 . The method of  claim 8 , wherein the biodegradable polymer is in a form selected from the group consisting of coating, sheet and combinations thereof. 
     
     
         14 . The method of  claim 13 , wherein the coating comprises electrospun fibers. 
     
     
         15 . The method of  claim 8 , wherein the one or more connectors is in a form selected from the group consisting of strut, wire, tube and combinations thereof. 
     
     
         16 . A stent delivery catheter system, comprising:
 a structural frame, elastically deformable from an original structure to a collapsed structure, comprising:
 a plurality of elongated segments composed of biodegradable metal, 
   wherein the biodegradable metal constitutes about 80% or greater of the total mass of the device;
 one or more connectors composed of nitinol structured to join together the plurality of elongated segments, 
   wherein a total of the nitinol constitutes about 10% or less of the total mass of the device; and
 a material comprising biodegradable polymer applied to at least a portion of the structural frame, 
   wherein the biodegradable polymer constitutes about 10% or less of the total mass of the device, and   wherein one or more pairs of the plurality of elongated segments are connected together by the one or more connectors to form the structural frame;   a delivery catheter for receiving the collapsed structure; and   a pushrod configured to deploy the collapsed structure from the catheter to thereby position the original structure at a vascular target site.   
     
     
         17 . The stent delivery catheter system of  claim 16 , wherein the delivery catheter is a silicon tube. 
     
     
         18 . The stent delivery catheter system of  claim 16 , wherein the biodegradable metal is a metal wire. 
     
     
         19 . The stent delivery catheter system of  claim 16 , wherein the biodegradable polymer is in a form selected from the group consisting of coating, sheet and combinations thereof.