Early Feasibility Study of the RelayBranch Thoracic Stent-Graft System

Inclusion Criteria: * Age ≥18 years * Anatomy that would require coverage of the brachiocephalic trunk (BCT) and/or left carotid arteries if a non-branch endograft were implanted * At least one of the following: 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 aortic dissection distal to the BCT (type B), 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 d. IMH distal to the BCT with recurrent symptoms, i.e. hypertension or intractable pain, despite best medical therapy. * A non-aneurysmal proximal aortic neck diameter ranging between 28 mm and 43 mm and a non-aneurysmal distal aortic neck diameter ranging between 19 mm and 43 mm. * A proximal attachment zone of the arch graft, meeting the oversizing requirement, must be a minimum of 25mm in length when measured on the inner curve of the ascending aorta, proximal to the BCT. * Total length from the coronaries to the proximal edge of the BCT must be a minimum of 70mm. * The length of the distal landing zone should be 20mm minimum. * Coverage of…