Clinical Study to Evaluate the Safety and Effectiveness of Arcevo LSA

General Inclusion Criteria

• ≥18 years of age or ≤80 years of age (male or female) at time of surgery
• Patient has one of the following indications for open surgery based on computed tomography angiography (CTA) completed within 90 days of informed consent:

• Acute, subacute, or chronic dissection that involves the aortic arch and the descending thoracic aorta, with or without involvement of the ascending aorta
• Aneurysm that involves the aortic arch and the descending thoracic aorta, with or without involvement of the ascending aorta
• Patient, or patient's legally authorized representative (LAR; in the secondary arm only), provides written informed consent prior to any study procedures
• Patient's surgery occurs within 90 days of informed consent

Anatomical Inclusion Criteria

• Aortic diameter at the intended Arcevo™ LSA anastomosis site is ≥ 21 mm
• For Aneurysm with distal sealing (i.e., single stage procedure), aortic diameter at the intended distal sealing zone is between 20-36 mm
• For Dissection with distal sealing, aortic diameter at the intended distal sealing zone is between 22-40 mm
• LSA branch does not require additional stenting further into the LSA (beyond the Arcevo™ LSA)
• The intended LSA sealing zone has a diameter between 8.5 mm and 14.0 mm with a length of at least 10 mm
• Absence of dissection, aneurysm, or stenosis in the intended LSA sealing zone
• The intended LSA branch position does not interrupt flow to any branch vessel (e.g., left vertebral artery)
• Patient does not have computed tomography (CT) evidence of extreme arch or LSA angulation precluding safe passage of the Arcevo™ LSA and delivery system
• LSA take-off angle between 15° and 90°
• For patients requiring planned extension, there is a ≥ 2 cm distal seal zone for the TEVAR device without a severely angulated descending aorta
• For patients requiring planned extension, patient has suitable iliac artery anatomy for safe passage of the TEVAR delivery system

General Exclusion Criteria

• Patient is pregnant, or planning to become pregnant during the course of the study; individuals of child-bearing potential must agree to use acceptable methods of contraception during the study
• Patient has another medical condition (aside from the arch disease) that, in the opinion of the investigator, reduces the patient's life expectancy to \< 2 years
• Patient has an existing aortic stent graft device in the descending aorta that would interact with Arcevo™ LSA
• Patient has a medical, social, or psychological problem that, in the opinion of the investigator, could impede the patient's ability to return for follow-up
• Patient is unwilling or unable to comply with the follow-up schedule
• Patient is institutionalized due to administrative or judicial order
• Patient is unwilling to accept blood transfusion or blood product
• Patient is currently participating in another interventional clinical study which includes treatment with another investigational product (e.g., device, pharmaceutical or biologic)

Medical Exclusion Criteria

• Patient is unfit for open surgical repair involving circulatory arrest
• Patient is in extreme hemodynamic compromise requiring cardiopulmonary resuscitation (CPR) or substantial inotropic support prior to surgery
• Patient has an active systemic infection
• Patient has endocarditis or active infection of the aorta
• Patient has a freely ruptured aorta
• Patient has a history of a bleeding disorder (e.g., hemophilia)
• Patient has current end-stage renal disease (e.g., GFR \<30 mL/min)
• Patient has a known allergy to Arcevo™ LSA components and TEVAR device components (if required) (nitinol, polyester, platinum-iridium, or polyethylene)
• Patient has uncontrollable anaphylaxis to iodinated contrast or other inability to obtain CT angiograms during follow-up
• Patient has acute coronary malperfusion
• Patient has symptomatic visceral malperfusion