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.

Inclusion Criteria:

• Subjects with diagnosed descending thoracic aneurysm or penetrating ulcer
• Subjects whose anatomy can accommodate the Relay device
• Subjects who consent to participate
• Subjects who agree to a follow-up schedule

Exclusion Criteria:

• Subjects with lesions other than thoracic aneurysm and penetrating ulcer
• Subjects with less than 1 year life expectancy
• Subjects who are pregnant
• Subjects with medical conditions that wold complicate the endovascular procedure or confound results (e.g., Marfan's syndrome, morbid obesity, severe coronary artery disease)
• Subjects participating in another investigational study