Patent ID: 8382825

Claim:
A system comprising: a self-expanding device comprising, in a cross-section, a first layer having strands and a second layer having strands, the strands of the first layer and the strands of the second layer being helically wound in a lattice structure arranged as a flexible tubular body; wherein the first layer of the self-expanding device comprises a first cross-sectional diameter, wherein each said strand of the first layer is circumferentially spaced from an adjacent said strand of the first layer device by an arc angle calculated by dividing 360 degrees by the number of strands in the first layer, wherein, with respect to a delivery device, each said strand of the first layer comprises a strand cross-sectional dimension being about equal to or less than (a circumference of an inner surface of the delivery device)/(a total number of strands in the first layer); and wherein the second layer of the device comprises a second cross-sectional diameter different than the first cross-sectional diameter, wherein each said strand of the second layer is circumferentially spaced from an adjacent said strand of the second layer by the arc angle, wherein each said strand of the second layer comprises the strand cross-sectional dimension; wherein the self-expanding device is configured to have a surface coverage that is less than or equal to 40% when expanded out of the delivery device.