Stent braid pattern with enhanced radiopacity

Abstract

An implantable metallic braid is formed out of groups of filaments of a first material, groups of filaments of a second material different from the first material, and groups of filaments of a third material different from the first material and the second material. The filaments are braided together by a braiding machine and are arranged in a starting filament arrangement on the braiding machine before braiding begins, wherein the first material is a radiopaque material, the second material is a support material, and the third material is a DFT comprising the first and second materials. Different arrangements of the filaments in the starting filament arrangement and in the braid result in different levels of detail that can be observed in images of the braid, wherein certain arrangements of the filaments result in enhanced radiopacity without affecting other mechanical properties of the braid.

What is claimed is: 
     
         1 . An implantable braid, comprising:
 a plurality of groups of first filaments, said first filaments being formed out of a first material;   a plurality of groups of second filaments, said second filaments being formed out of a second material different from the first material; and   a plurality of groups of third filaments, said first filaments being formed out of a third material different from the first material and the second material,   wherein the respective groups of first filaments, second filaments, and third filaments are braided together in a starting filament arrangement in which each group of second filaments is positioned directly adjacent to one of the groups of first filaments,   each group of third filaments is positioned directly adjacent to one of the groups of second filaments,   each group of first filaments has one of the groups of second filaments directly adjacent thereto, and   each group of second filaments is directly adjacent to one of the groups of first filaments on one side, and directly adjacent to one of the groups of third filaments on another side.   
     
     
         2 . The braid of  claim 1 , wherein the second material is one of a monofilament and a drawn filled tube (DFT) wire, the DFT wire comprising a core and a sheath around the core. 
     
     
         3 . The braid of  claim 2 , wherein the third material is the other one of the monofilament and the DFT wire. 
     
     
         4 . The braid of  claim 3 , wherein the first material is a radiopaque material and the monofilament is a support material having a tensile strength greater than a tensile strength of the radiopaque material. 
     
     
         5 . The braid of  claim 3 , wherein the DFT wire comprises a radiopaque material and a support material having a tensile strength greater than a tensile strength of the radiopaque material. 
     
     
         6 . The braid of  claim 5 , wherein the DFT wire core is made from the radiopaque material, and the DFT wire sheath is made from the support material. 
     
     
         7 . The braid of  claim 6 , wherein the radiopaque material is platinum and the support material is cobalt chromium alloy. 
     
     
         8 . The braid of  claim 7 , wherein the cobalt chromium alloy is one of 1058 CoCr alloy and 35N LT® Superalloy. 
     
     
         9 . The braid of  claim 3 , wherein the second material is the monofilament and the third material is the DFT wire. 
     
     
         10 . The braid of  claim 1 , wherein each group of first filaments consists of two filaments of the first material, each group of second filaments consists of two filaments of the second material, and each group of third filaments consists of two filaments of the third material. 
     
     
         11 . The braid of  claim 1 , wherein the first material is platinum, the second material is cobalt chromium alloy, and the third material is a DFT wire comprising a platinum core and a sheath made of the cobalt chromium alloy. 
     
     
         12 . The braid of  claim 1 , wherein the braid is tubular. 
     
     
         13 . A metallic braid for implantation within a human body, wherein the braid comprises:
 a plurality of groups of first filaments, wherein the first filaments are formed out of a first material; and   a plurality of groups of second filaments, wherein the second filaments are formed out of a second material different from the first material,   wherein one of the first material and the second material is a drawn filled tube (DFT) wire,   wherein the groups of first filaments and the groups of second filaments are braided together by a braiding machine and are arranged in a starting filament arrangement on the braiding machine before braiding begins, and   wherein, in the starting filament arrangement, each group of second filaments is positioned directly adjacent to one of the groups of first filaments.   
     
     
         14 . The braid of  claim 13 , wherein the first material is a radiopaque material, and the second material is the DFT wire. 
     
     
         15 . The braid of  claim 13 , wherein the DFT wire comprises a core and a sheath surrounding the core, wherein one of the sheath and the core is made of a radiopaque material, and the other of the sheath and the core is made of a support material having a higher tensile strength than a tensile strength of the radiopaque material. 
     
     
         16 . The braid of  claim 13 , wherein the DFT wire comprises a platinum core and a cobalt chromium alloy sheath surrounding the platinum core. 
     
     
         17 . The braid of  claim 16 , wherein the cobalt chromium alloy is alloy L605. 
     
     
         18 . The braid of  claim 16 , wherein the platinum core has a cross-sectional area between 20% to 30% of a total cross-sectional area of the DFT wire. 
     
     
         19 . The braid of  claim 13 , wherein every filament that forms the braid is made of the first material or the second material. 
     
     
         20 . The braid of  claim 13 , wherein the braid is tubular.