Stent and stent-graft for treating branched vessels

Abstract

An implantable stent and stent-graft for treating a patient having a relatively healthy first aorta portion upstream from a renal artery branch, and a diseased aorta portion downstream from the renal artery branch. One embodiment of the device includes a fixation section, a renal artery branch section and a diseased aorta section, all of which can be tubular, radially compressible and self-expandable structures formed from a plurality of filaments which are helically wound in a braided configuration. When the device is implanted and in its expanded state, the fixation section engages the first aorta portion upstream from a renal artery branch to provide substantial anchoring support. The diseased aorta section engages the portion of the aorta downstream from the renal artery branch and extends across the diseased portion of the aorta for purposes of treatment. The renal artery branch section extends across the renal artery branch and connects the diseased aorta section to the fixation section while allowing blood flow between the aorta and renal artery branch.

What is claimed is:  
     
         1 . An implantable medical device for treating a section of a patient's vessel having a vessel branch, a relatively healthy first vessel portion on a first side of the vessel branch, and a diseased vessel portion on a second side of the vessel branch, including: 
 a fixation section comprising a plurality of filaments which are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure, for engaging the first vessel portion on the first side of the vessel branch when in an expanded state to provide substantial anchoring support for the implanted medical device;    a diseased section comprising a plurality of filaments which are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure, for engaging a portion of the vessel on the second side of the vessel branch and extending across and treating the diseased vessel portion; and    a branch section comprising a radially compressible and expandable structure, for extending across the vessel branch and connecting the diseased section to the fixation section while allowing blood flow to the vessel branch.    
     
     
         2 . The implantable medical device of  claim 1  wherein the branch section includes a plurality of filaments extending between the fixation section and the diseased section.  
     
     
         3 . The implantable medical device of  claim 2  wherein the branch section filaments are generally parallel to one another and have opposite ends wrapped around the filaments of the fixation section and the diseased section.  
     
     
         4 . The implantable medical device of  claim 2  wherein the filaments of the branch section are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure.  
     
     
         5 . The implantable medical device of  claim 4  wherein a free state diameter of the fixation section is equal to a free state diameter of the branch section.  
     
     
         6 . The implantable medical device of  claim 4  wherein a radial pressure of the fixation section is greater than a radial pressure of the branch section.  
     
     
         7 . The implantable medical device of  claim 6  wherein the radial pressure of the fixation section is greater than a radial pressure of the diseased section.  
     
     
         8 . The implantable medical device of  claim 4  wherein a density of the filaments in the branch section is less than a density of the filaments in the fixation section.  
     
     
         9 . A method for manufacturing the medical device of  claim 8 , including: 
 helically winding filaments to form a tubular fixation section and a tubular branch section having the same density of filaments; and    removing some of the filaments from the branch section.    
     
     
         10 . The method of  claim 9  wherein helically winding filaments includes forming a tubular fixation section and a tubular branch section having the same free state diameter.  
     
     
         11 . The method of  claim 9  and further including: 
 helically winding filaments to form a fixation section, branch section and diseased section having the same density of filaments; and  
 removing some of the filaments from the branch section.  
 
     
     
         12 . The method of  claim 11  wherein helically winding filaments includes forming a tubular fixation section, branch section and diseased section having the same free state diameter.  
     
     
         13 . A method for manufacturing the medical device of  claim 8 , including: 
 helically winding filaments at a first braid angle to form the tubular structure of the fixation section; and    helically winding the filaments at a second braid angle which is less than the first braid angle to form the tubular structure of the branch section.    
     
     
         14 . The method of  claim 13  wherein helically winding filaments includes forming a tubular fixation section and tubular branch section having the same free state diameter.  
     
     
         15 . The method of  claim 13  and further including: 
 helically winding filaments at a third braid angle which is greater than the second braid angle to form the tubular structure of the diseased section.  
 
     
     
         16 . The method of  claim 15  wherein helically winding filaments includes forming a tubular fixation section, tubular branch section and tubular diseased section having the same free state diameter.  
     
     
         17 . The implantable medical device of  claim 8  wherein the density of the filaments in the branch section is less than a density of the filaments in the diseased section.  
     
     
         18 . The implantable medical device of  claim 8  wherein the density of the filaments in the branch section is equal to a density of the filaments in the diseased section.  
     
     
         19 . A method for implanting the medical device of  claim 1  in a diseased vessel, including: 
 providing the device in a radially compressed state;  
 delivering the device to the diseased vessel and positioning the fixation section within the healthy first vessel portion, the branch section within the vessel branch, and the diseased section within the diseased vessel portion; and  
 causing the device to radially self-expand with the fixation section engaging the first vessel portion, the branch section extending cross the vessel branch, and the diseased section extending across and engaging the diseased portion.  
 
     
     
         20 . An implantable stent-graft for treating a section of a patient's vessel having a vessel branch, a relatively healthy first vessel portion on a first side of the vessel branch, and a diseased vessel portion on a second side of the vessel branch; including: 
 a fixation section comprising a plurality of filaments which are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure, for engaging the first vessel portion on the first side of the vessel branch when in an expanded state to provide substantial anchoring support for the implanted medical device;    a diseased section comprising: 
 a plurality of filaments which are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable support structure, for engaging a portion of the vessel on the second side of the vessel branch and extending across and treating the diseased vessel portion; and  
 a radially-expandable membrane coextensive with at least a portion of the length of the support structure; and  
   a branch section comprising a radially compressible and expandable structure, for extending across the vessel branch and connecting the diseased section to the fixation section while allowing blood flow to the vessel branch.    
     
     
         21 . The stent-graft of  claim 20  wherein the membrane is coextensive with at least 75% of a continuous length of the diseased section.  
     
     
         22 . The stent-graft of  claim 20  wherein the membrane is formed of braided filaments.  
     
     
         23 . The stent-graft of  claim 22  wherein the membrane is formed of braided polymeric filaments.  
     
     
         24 . The stent-graft of  claim 22  wherein the membrane is formed of filaments interbraided with one another and the filaments of the support structure.  
     
     
         25 . The stent-graft of  claim 20  wherein the branch section includes a plurality of filaments extending between the fixation section and the diseased section.  
     
     
         26 . The stent-graft of  claim 25  wherein the branch section filaments are generally parallel to one another and have opposite ends wrapped around the filaments of the fixation section and the diseased section.  
     
     
         27 . The stent-graft of  claim 25  wherein the filaments of the branch section are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure.  
     
     
         28 . The stent-graft of  claim 27  wherein a free state diameter of the fixation section is equal to a free state diameter of the branch section.  
     
     
         29 . The stent-graft of  claim 27  wherein a radial pressure of the fixation section is greater than a radial pressure of the branch section.  
     
     
         30 . The stent-graft of  claim 29  wherein the radial pressure of the fixation section is greater than a radial pressure of the diseased section.  
     
     
         31 . The stent-graft of  claim 27  wherein a density of the filaments in the branch section is less than a density of the filaments in the fixation section.  
     
     
         32 . A method for manufacturing the stent-graft of  claim 31 , including: 
 helically winding and braiding filaments to form a tubular fixation section and a tubular branch section having the same density of filaments; and    removing some of the filaments from the branch section.    
     
     
         33 . The method of  claim 32  wherein helically winding and braiding filaments includes forming a tubular fixation section and a tubular branch section having the same free state diameter.  
     
     
         34 . The method of  claim 32  and further including: 
 helically winding and braiding filaments to form a fixation section, branch section and diseased section having the same density of filaments; and  
 removing some of the filaments from the branch section.  
 
     
     
         35 . The method of  claim 34  wherein helically winding and braiding filaments includes forming a tubular fixation section branch section and diseased section having the same free state diameter.  
     
     
         36 . A method for manufacturing the stent-graft of  claim 31 , including: 
 helically winding and braiding filaments at a first braid angle to form the tubular structure of the fixation section; and    helically winding and braiding the filaments at second braid angle which is less than the first braid angle to form the tubular structure of the branch section.    
     
     
         37 . The method of  claim 36  wherein helically winding and braiding filaments includes forming a tubular fixation section and tubular branch section having the same free state diameter.  
     
     
         38 . The method of  claim 36  and further including: 
 helically winding and braiding filaments at a third braid angle which is greater than the second braid angle to form the tubular structure of the diseased section.  
 
     
     
         39 . The method of  claim 38  wherein helically winding and braiding filaments includes forming a tubular fixation section, tubular branch section and tubular diseased section having the same free state diameter.  
     
     
         40 . The stent-graft of  claim 31  wherein the density of the filaments in the branch section is less than a density of the filaments in the diseased section.  
     
     
         41 . The stent-graft of  claim 31  wherein the density of the filaments in the branch section is equal to a density of the filaments in the diseased section.  
     
     
         42 . A method for implanting the stent-graft of  claim 20 , including: 
 providing the device in a radially compressed state;    delivering the device to the diseased vessel and positioning the fixation section within the healthy first vessel portion, the branch section within the vessel branch, and the diseased aorta section within the diseased portion; and    causing the device to radially self-expand with the fixation section engaging the first vessel portion, the branch section extending cross the vessel branch, and the diseased section extending across and engaging the diseased vessel portion.    
     
     
         43 . An implantable medical device for treating a portion of a patient's vessel having a branch, a first portion on a first side of the branch, and a second portion on a second side of the branch, including: 
 a first section having a first porosity and comprising a plurality filaments which are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure, for engaging the first portion of the vessel on the first side of the branch;    a second section having a second porosity and comprising a plurality filaments which are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure, for engaging the second portion of the vessel on the second side of the branch; and    a branch section having a third porosity which is less than at least one of the first and second porosities and comprising a radially compressible and expandable structure, for extending across the branch and connecting the first and second sections while allowing blood flow to the branch.    
     
     
         44 . The implantable medical device of  claim 43  wherein the filaments of the branch section are helically wound in a braided configuration to form a tubular, radially compressible and self-expandable structure.  
     
     
         45 . The implantable medical device of  claim 44  wherein free state diameters of the first section, second section and branch section are equal to one another.  
     
     
         46 . The implantable medical device of  claim 44  wherein the second section includes a radially-expandable and relatively low porosity membrane coextensive with at least a portion of the length of the self-expandable structure.  
     
     
         47 . The implantable medical device of  claim 46  wherein the second section membrane is formed of braided filaments.  
     
     
         48 . The implantable medical device of  claim 47  wherein the second section membrane is formed of filaments interbraided with one another and the filaments of the self-expandable structure.  
     
     
         49 . The implantable medical device of  claim 46  wherein the first section includes a radially-expandable and relatively low porosity membrane coextensive with at least a portion of the length of the self-expandable structure.  
     
     
         50 . The implantable medical device of  claim 49  wherein the first section membrane is formed of braided filaments.  
     
     
         51 . The implantable medical device of  claim 50  wherein the first section membrane is formed of filaments braided with one another and the filaments of the self-expandable structure.