Method of radially-asymmetric stent expansion
This invention gives physicians in situ control to create differences in wall porosity between different areas of a stent wall. This enables a physician to customize the stent within a blood vessel to selectively block blood flow to an aneurysm with a low-porosity area of the stent wall, but allow blood flow to nearby branching vessels through one or more high-porosity areas of the stent wall. The method comprises inserting a stent into a blood vessel and, in situ, expanding the stent in a non-uniform manner, thereby causing one or more areas of the stent wall to have a lower post-expansion porosity than the rest of the stent wall. With this invention, physicians can selectively block blood flow into an aneurysm while maintaining blood flow into nearby branching vessels, even in tortuous and complex vessel configurations.
1. A method of creating differences in porosity between portions of a cross-sectional perimeter of a stent wall comprising:
inserting a stent into a blood vessel, wherein the stent has multiple cross-sectional perimeters including a selected cross-sectional perimeter;
expanding a first portion of the selected cross-sectional perimeter of the stent by inflating a first inflatable member, wherein the first portion has a first porosity level before inflation of the first inflatable member and a second porosity level after inflation of the first inflatable member;
expanding a second portion of the selected cross-sectional perimeter of the stent by inflating a second inflatable member, wherein the second portion has a third porosity level before inflation of the second inflatable member and a fourth porosity level after inflation of the second inflatable member, wherein the difference between the second porosity level and the fourth porosity level is greater than the difference between the first porosity level and the third porosity level, wherein the first inflatable member and the second inflatable member each have a lateral cross section that spans a portion of the interior of the selected cross-sectional perimeter of the stent, and wherein there is a non-inflatable core between the first inflatable member and the second inflatable member; and
removing the first inflatable member, the second inflatable member, and the non-inflatable core from the stent.