Vascular stenting for aneurysms

Abstract

Described herein are flexible implantable occluding devices that can, for example, navigate the tortuous vessels of the neurovasculature. The occluding devices can also conform to the shape of the tortuous vessels of the vasculature. In some embodiments, the occluding devices can direct blood flow within a vessel away from an aneurysm or limit blood flow to the aneurysm. Some embodiments describe methods and apparatus for adjusting, along a length of the device, the porosity of the occluding device. In some embodiments, the occluding devices allows adequate blood flow to be provided to adjacent structures such that those structures, whether they are branch vessels or oxygen-demanding tissues, are not deprived of the necessary blood flow.

What is claimed is: 
     
         1 . A braided stent, for implanting in a patient's vessel, comprising:
 a plurality of braided strands, having an average strand thickness, the plurality of braided strands forming pores in open areas between strands;   wherein the stent is expandable from a compressed configuration to an expanded configuration;   wherein the pores have an average pore length;   wherein the stent has a porosity equal to a ratio of an open surface area of the stent to a total surface area of the stent;   wherein, when the stent is in the expanded configuration, the porosity of the stent multiplied by the average pore length is equal to or less than about 0.3 mm.   
     
     
         2 . The stent of  claim 1 , wherein each of the braided members comprises a ribbon having a width greater than its thickness. 
     
     
         3 . The stent of  claim 1 , wherein each of the braided members comprises a ribbon having a width that is substantially equal to its thickness. 
     
     
         4 . The stent of  claim 1 , wherein the porosity of a portion of the stent can be reduced by axially compressing the portion of the stent. 
     
     
         5 . The stent of  claim 4 , wherein the axially compressed portion of the stent axially expands when unrestrained. 
     
     
         6 . The stent of  claim 4 , wherein the porosity of a portion of the stent can be reduced to between about 5 percent and about 50 percent. 
     
     
         7 . The stent of  claim 4 , wherein when the stent is in the expanded configuration, the porosity of the stent multiplied by the average pore length multiplied by the average strand thickness is equal to or less than about 0.023 mm 2 . 
     
     
         8 . A braided stent, for implanting in a patient's vessel, comprising:
 a plurality of braided strands, having an average strand thickness, the plurality of braided strands forming pores in open areas between strands;   wherein the stent is expandable from a compressed configuration to an expanded configuration;   wherein the pores have an average pore length;   wherein the stent has a porosity equal to a ratio of an open surface area of the stent to a total surface area of the stent;   wherein, when the stent is in the expanded configuration, the porosity of the stent multiplied by the average strand thickness is equal to or less than about 0.002 inches.   
     
     
         9 . The stent of  claim 8 , wherein the average strand thickness is less than about 0.004 inches. 
     
     
         10 . The stent of  claim 8 , wherein the average strand thickness is equal to or less than about 0.003 inches. 
     
     
         11 . The stent of  claim 8 , wherein the average strand thickness is equal to or less than about 0.002 inches. 
     
     
         12 . The stent of  claim 8 , wherein the average strand thickness is equal to or less than about 0.001 inches. 
     
     
         13 . The stent of  claim 8 , wherein when the stent is in the expanded configuration, the average strand thickness multiplied by the average pore length is equal to or less than about 0.0328 mm 2 . 
     
     
         14 . The stent of  claim 8 , wherein the pores have an average pore area defined by an inner edge of bordering strands, the average pore area ranging from about 2.2×10 −5  in 2  to about 12.3×10 −5  in 2 . 
     
     
         15 . The stent of  claim 8 , wherein when the stent is in the expanded configuration, the average strand thickness multiplied by the average pore area is between about 2.2×10 −9  in 3  and about 3.69×10 −7  in 3 . 
     
     
         16 . A braided stent, for implanting in a patient's vessel, comprising:
 a plurality of braided strands, having an average strand thickness, the plurality of braided strands forming pores in open areas between strands;   wherein the stent is expandable from a compressed configuration to an expanded configuration;   wherein the pores have an average pore length;   wherein the stent has a porosity equal to a ratio of an open surface area of the stent to a total surface area of the stent;   wherein, when the stent is in the expanded configuration, the average pore length multiplied by the average strand thickness is equal to or less than about 9.4×10 −5  in 2 .   
     
     
         17 . The stent of  claim 16 , wherein the average pore length multiplied by the average strand thickness is equal to or less than about 6.8×10 −5  in 2 . 
     
     
         18 . The stent of  claim 16 , wherein the average pore length multiplied by the average strand thickness is equal to or less than about 5×10 −5  in 2 .