Multi-layer braided structures for occluding vascular defects

Abstract

A collapsible medical device and associated methods of occluding an abnormal opening in, for example, a body organ, wherein the medical device is shaped from plural layers of a heat-treatable metal fabric. Each of the fabric layers is formed from a plurality of metal strands and the assembly is heat-treated within a mold in order to substantially set a desired shape of the device. By incorporating plural layers in the thus-formed medical device, the ability of the device to rapidly occlude an abnormal opening in a body organ is significantly improved.

1 . A collapsible medical device comprising:
 an outer metal fabric layer having a first plurality of braided metal strands; and   an inner metal fabric layer concentric with the outer fabric layer and having a second plurality of braided metal strands,   the medical device having an expanded preset configuration with:
 a first expanded diameter portion; 
 a second expanded diameter portion; and 
 a waist portion coupling the first expanded diameter portion to the second expanded diameter portion, the waist having a first outer edge portion and a second outer edge portion, wherein a shape of the first outer edge portion differs from a shape of the second outer edge portion when the medical device is in the expanded preset configuration, 
   the outer and inner metal fabric layers having a memory property such that the medical device tends to return to the expanded preset configuration when unconstrained.   
     
     
         2 . The medical device of  claim 1 , wherein a diameter of the metal strands of the second plurality of braided metal strands is less than a diameter of the metal strands of the first plurality of braided metal strands. 
     
     
         3 . The medical device of  claim 2 , wherein the diameter of metal strands of the first plurality of braided metal strands is in a range from 0.0015 inches to 0.0035 inches. 
     
     
         4 . The medical device of  claim 2 , wherein the diameter of metal strands of the second plurality of braided metal strands is in a range from 0.001 inches to 0.002 inches. 
     
     
         5 . The medical device of  claim 1 , wherein the number of braided metal strands of the first plurality of braided metal strands is 144. 
     
     
         6 . The medical device of  claim 1 , wherein the number of braided metal strands of the second plurality of braided metal strands is 144. 
     
     
         7 . The medical device of  claim 1 , further comprising a first clamp coupling together proximal ends of the inner and outer metal fabric layers, the first clamp defining a bore for receiving a distal end of a delivery device. 
     
     
         8 . The medical device of  claim 7 , wherein the bore is internally threaded. 
     
     
         9 . The medical device of  claim 7 , wherein the first clamp is externally threaded. 
     
     
         10 . The medical device of  claim 1 , further comprising a second clamp coupling together distal ends of the inner and outer metal fabric layers. 
     
     
         11 . The medical device of  claim 1 , wherein the inner and outer metal fabric layers have a same shape. 
     
     
         12 . The medical device of  claim 1 , wherein, in the expanded preset configuration, the first and second expanded diameter portions have a crescent shape. 
     
     
         13 . The medical device of  claim 1 , wherein, in the expanded preset configuration, the first and second expanded diameter portions have a circular shape. 
     
     
         14 . The medical device of  claim 1 , wherein, in the expanded preset configuration, the first and second expanded diameter portions have an ovular shape. 
     
     
         15 . The medical device of  claim 1 , wherein in the expanded preset configuration, the first expanded diameter portion includes a first section that is planar and transverse to a central axis of the medical device and a second section that is angled with respect to the central axis. 
     
     
         16 . The medical device of  claim 15 , wherein the second section of the first expanded diameter portion is aligned with the second outer edge portion of the waist portion, along a direction parallel to the central axis of the medical device. 
     
     
         17 . The medical device of  claim 16 , wherein in the expanded preset configuration, the second expanded diameter portion includes a first section that is planar and transverse to the central axis of the medical device and a second section that is angled with respect to the central axis. 
     
     
         18 . The medical device of  claim 17 , wherein the second sections of the first and second expanded diameter portions are aligned with the second outer edge portion of the waist portion, along a direction parallel to the central axis of the medical device. 
     
     
         19 . The medical device of  claim 15 , wherein the second section of the first expanded diameter portion is angled away from the waist portion. 
     
     
         20 . The medical device of  claim 15 , wherein the first and second sections are continuous with one another.