 This study is a continuation of the pivotal trial studying the safety and efficacy of the Relay thoracic stent-graft system to treat thoracic aortic aneurysms. Efficacy is being evaluated by the device-related adverse event rate of endovascular repair via the Relay thoracic stent-graft through 1 year. Safety is being evaluated by comparing major adverse events through 1 year in subjects treated with the Relay thoracic stent-graft to those who underwent surgical repair. 