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.

What is claimed is: 
     
         1 - 103 . (canceled) 
     
     
         104 . A medical device for occluding a target site, the medical device comprising:
 a tubular fabric structure having proximal and distal ends and a preset, expanded configuration, wherein the tubular fabric structure comprises at least one layer of braided fabric comprising a plurality of braided strands, the plurality of braided strands having ends secured together at each of the proximal and distal ends, the tubular fabric structure configured to be constrained to a reduced configuration for delivery to the target site and to at least partially return to the preset, expanded configuration within the target site when unconstrained, wherein the preset, expanded configuration comprises at least three expanded volume sections and a plurality of intermediate clamps arranged in a repeating pattern with each intermediate clamp extending between a pair of expanded volume sections, and each expanded volume section having a cross-sectional dimension that is larger than a cross-sectional dimension of a respective intermediate clamp, and wherein at least one expanded volume section has a cross-sectional dimension at least as large as that of the target site and is generally spherical or ovaloid in shape in the preset, expanded configuration.   
     
     
         105 . The medical device of  claim 104 , wherein a plurality of the expanded volume sections are generally spherical or ovaloid in shape in the preset, expanded configuration. 
     
     
         106 . The medical device of  claim 104 , wherein said at least one layer of braided fabric comprises a shape memory alloy. 
     
     
         107 . The medical device of  claim 104 , further comprising a pair of end clamps, wherein the plurality of braided strands at each of the proximal and distal ends are secured together with a respective end clamp. 
     
     
         108 . The medical device of  claim 107 , wherein at least one of the end clamps comprises a threaded connection configured to be coupled to a delivery device. 
     
     
         109 . The medical device of  claim 107 , wherein each of the end clamps comprises a threaded connection. 
     
     
         110 . The medical device of  claim 104 , wherein the tubular fabric structure is configured to be disposed longitudinally within the target site such that at least one expanded volume section is configured to engage a lumen of the target site. 
     
     
         111 . The medical device of  claim 104 , wherein each of the expanded volume sections has a cross-sectional dimension at least as large as that of the target site. 
     
     
         112 . The medical device of  claim 104 , wherein each expanded volume section has approximately the same maximum outer diameter in the preset, expanded configuration. 
     
     
         113 . The medical device of  claim 104 , wherein the plurality of braided strands are secured together at the proximal end or the distal end of the tubular fabric structure such that at least one of the proximal or distal ends of the tubular fabric structure is closed and thereby configured to substantially occlude flow between the proximal and distal ends. 
     
     
         114 . The medical device of  claim 113 , wherein the plurality of braided strands are secured together at the proximal end and the distal end of the tubular fabric structure such that the proximal and distal ends of the tubular fabric structure are closed and thereby configured to substantially occlude flow between the proximal and distal ends. 
     
     
         115 . The medical device of  claim 104 , wherein at least one of the expanded volume sections is configured to substantially occlude flow between the proximal and distal ends of the tubular fabric structure. 
     
     
         116 . The medical device of  claim 104 , wherein the tubular fabric structure is configured to self expand and at least partially return to the preset, expanded configuration within the target site when unconstrained. 
     
     
         117 . A method for delivering an occlusion device to a target site, the method comprising:
 providing an occlusion device comprising a tubular fabric structure having proximal and distal ends and a preset, expanded configuration, wherein the tubular fabric structure comprises at least one layer of braided fabric comprising a plurality of braided strands, the plurality of braided strands having ends secured together at each of the proximal end and the distal end, wherein the preset, expanded configuration comprises at least three expanded volume sections and a plurality of intermediate clamps arranged in a repeating pattern with each intermediate clamp extending between a pair of expanded volume sections, and each expanded volume section having a cross-sectional dimension that is larger than a cross-sectional dimension of a respective intermediate clamp, wherein at least one expanded volume section has a cross-sectional dimension at least as large as that of the target site and is generally spherical or ovaloid in shape in the preset, expanded configuration;   constraining the occlusion device from the preset, expanded configuration to a reduced configuration;   positioning the constrained occlusion device in a catheter;   delivering the constrained occlusion device to the target site; and   deploying the constrained occlusion device from the catheter such that the occlusion device at least partially returns to the preset, expanded configuration within the target site.   
     
     
         118 . The method of  claim 117 , wherein said deploying comprises deploying the occlusion device such that the occlusion device is disposed longitudinally within the target site. 
     
     
         119 . The method of  claim 117 , wherein said deploying comprises deploying the occlusion device such that at least one expanded volume section engages a lumen of the target site. 
     
     
         120 . The method of  claim 117 , wherein said deploying comprises deploying the occlusion device such that the occlusion device is disposed non-linearly within the target site. 
     
     
         121 . The method of  claim 117 , wherein said providing comprises providing an occlusion device having a plurality of generally spherical or ovaloid shaped expanded volume sections in the preset, expanded configuration. 
     
     
         122 . The method of  claim 117 , wherein said providing comprises providing an occlusion device including at least one expanded volume section having a cross-sectional dimension that is at least as large as a cross-sectional dimension of the target site. 
     
     
         123 . The method of  claim 117 , wherein said providing comprises providing an occlusion device including a plurality of expanded volume sections each having a cross-sectional dimension that is at least as large as a cross-sectional dimension of the target site.