Patent ID: 8894900

Claim:
A method of increasing the resistance to cracking in a high strain region of a balloon expandable polymer stent, the stent being formed from a first bioabsorbable polymer material, comprising the steps of: forming a cavity in the high strain region of the stent, wherein the cavity is surrounded entirely by an interior sidewall surface formed by cutting some of the first bioabsorbable material from the high strain region; and disposing a second bioabsorbable polymer material within the cavity, the second bioabsorbable polymer material having a modulus that is less than the modulus of the first bioabsorbable polymer material; wherein the cavity is located in a region where the centroidal axis of a strut does not coincide with the strut's neutral axis in bending when the stent is being radially compressed or expanded; wherein the cavity is long and narrow and has a variable width over a length of the high strain region, wherein the width is proportional to a magnitude of strain along the high strain region and the width is a maximum at a plane of bending symmetry for the strut; and wherein the cavity has a size to inhibit or prevent fracture when the stent is crimped or expanded from a balloon.