This test method covers the procedure for determining the durability of ballon-expandable and self- expanding metal or alloy vascular stents. Tests are performed by exposing specimens to physiologically relevant diametric distention levels using hydrodynamic pulsatile loading. Specimens should have been deployed into a mock or elastically simulated vessel prior to testing. The test methods are valid for determining stent failure due to typical cyclic blood vessel diametric distention and include physiological pressure tests and diameter control tests. These do not address other modes of failure such as dynamic bending, torsion, extension, crushing, or abrasion. Test apparatus include a pressure measurement system, dimensional measurement devices, a cycle counting system, and a temperature control system.