a. Aneurysm of the ascending aorta, aortic arch, or proximal descending aorta that meets at least one of the following: i. ≥ 5.5 cm in diameter ii. ≥ 4.0 cm in diameter that has increased in size by 0.5 cm in the last 6 months iii. Measures twice the size of the normal aorta diameter iv. Is saccular in configuration b. PAU within the ascending aorta, aortic arch, or proximal descending thoracic aorta (DTA) with or without intramural hematoma (IMH) c. Chronic, uncomplicated type B aortic dissection or IMH with time from symptom onset to diagnosis ≥ 60 days without malperfusion of the viscera, kidneys, spinal cord, or lower extremities and with either aortic diameter ≥5.5 cm or ≥4.0 cm with an increase in size by 0.5 cm in the last 6 months