Prospective, non-randomized, multi-center clinical investigation of the NEXUS™ Aortic Arch Stent Graft System (NEXUSTM) for the treatment of thoracic aortic lesions involving the aortic arch with a proximal landing zone, native or previously implanted surgical graft, in the ascending aorta and with a brachiocephalic trunk native landing zone.

Inclusion Criteria:

1. Male and female age ≥ 18.

2. Proximal/ascending native or previously implanted surgical graft landing zone of appropriate length

3. Proximal/ascending native or previously implanted surgical graft landing zone of appropriate diameter

4. Distal/descending native landing zone of appropriate length

5. Distal/descending native landing zone of appropriate diameter

6. Brachiocephalic trunk native landing zone of appropriate length

7. Brachiocephalic trunk native landing zone of appropriate diameter

8. Appropriate take off angle between the Brachiocephalic Artery and the Aortic Arch perpendicular

9. Appropriate aortic arch perpendicular diameter

10. Chronic dissection with at least one of the following conditions:

    1. An aortic aneurysm with a maximum diameter ≥ 55 mm
    2. Rapidly expanding false lumen (growth of > 0.5 cm/6 months)
    3. Compressed true lumen associated with end organ malperfusion
    4. Symptomatic

11. Aneurysm with at least one of the following conditions:

    1. Dilatation of the aortic arch larger than 5 cm in diameter for subject with fusiform aneurysm
    2. Dilatation of the aortic arch is 1.5 times the normal diameter for subjects ascending or descending
    3. Dilation of the aortic arch larger than 2.5 cm for subject with saccular aneurysm
    4. Symptomatic aneurysm of the aortic arch
    5. Aortic diameter growth rate > 5mm per 6 months
    6. Postoperative pseudoaneurysm expanding from anastomotic suture lines

12. Penetrating aortic ulcer with at least one of the following:

    1. Symptomatic
    2. Ulcer demonstrates expansion

13. Intramural hematoma with at least one of the following:

    1. Symptomatic (persistent pain)
    2. Transverse or longitudinal expansion on serial imaging

14. In the event of a lesion in the ascending aortic, the proximal/ascending native or previously implanted surgical graft the landing zone must be appropriate

15. Femoral / iliac artery diameter as documented by CTA or MRA that allows endovascular access to the diseased site with a 20 Fr. delivery catheter.

16. Access vessels morphology suitable for endovascular repair in terms of tortuosity, calcification and angulation, documented by CTA/MRA.

17. Brachial/Axial Artery diameter that allows endovascular access suitable for 7 Fr.

18. Subject is considered an appropriate candidate for an elective surgery.

19. Subject is considered to be at high risk for open repair, as determined by the investigator.

20. Access vessels, iliac/femoral & brachial/axillary compatible with vascular access techniques (femoral cutdown or percutaneous), devices, and /or accessories.

21. Subject is willing and able to comply with procedures specified in the protocol and is able to return for follow-up visits as specified by the protocol.

Exclusion Criteria:

1. Acute dissection
2. Lesions that can be safely treated with TEVAR landing in zone 2 (with or w/o LSA vascularization)
3. Required emergent treatment, e.g., trauma, rupture
4. Acute vascular injury of the aorta due to trauma
5. Aortic rupture or unstable aneurysm
6. Received a previous stent or stent graft in the treated area (including planned landing area)
7. Required surgical or endovascular treatment of an infra-renal aneurysm at time of implantation
8. Planned major surgical or interventional procedure at time of screening, to be performed after the NEXUS™ implantation.
9. Any major surgical or interventional procedure 6 weeks before the NEXUS™ implantation, exclusive of planned procedures that are needed for the safe and effective placement of the stent graft (e.g. supra-aortic bypass).
10. Subject has had a myocardial infarction (MI) or cerebral vascular accident (CVA) within 90 days prior to the planned implantation
11. Subjects with severe aortic valvular insufficiency as determined by echocardiography
12. Mechanical valve that preclude safe delivery of NEXUS™
13. Known Connective tissue disease (e.g., Marfan's or Ehler's-Danlos syndromes)
14. Subject has an active systemic infection at the time of the procedure documented by pain, fever, drainage, positive culture
15. Pregnant
16. Life expectancy of less than 2 years
17. Unsuitable vascular anatomy
18. Subject who have a previously implanted surgical wrap of the ascending aorta
19. Any medical condition that, according to the investigator's decision, might expose the subject to increased risk by the investigational device or procedure.
20. An aneurysm that is mycotic, inflammatory or suspected to be infected.
21. Subject with hostile groins/axilla (scarring, obesity, or previous failed puncture) unless conduit are used.
22. Subjects with severe atherosclerosis, severe calcification or extensive intraluminal thrombus of the aorta or in the brachiocephalic trunk
23. Subject is suffering from unstable angina or NYHA classification III and IV.
24. Subject has a known hypersensitivity or contraindication to anticoagulants, antiplatelets, or contrast media, which is not amenable to pre-treatment.
25. Subject with a contraindication to undergo angiography
26. Subject with known sensitivities or allergies to the device materials (including Nitinol [NiTi], polyester fabric [PET], tantalum [TA])
27. Clinical conditions that severely inhibit x-ray visualization of the Aorta.
28. Subject has history of bleeding diathesis or coagulopathy that may limit the use of dual antiplatelet or anticoagulant therapy by the decision of the investigator
29. Acute renal failure; chronic renal failure (excluding dialysis); Creatinine > 2.00 mg/dl
30. Any other medical, social, or psychological issues that in the opinion of the investigator preclude them from receiving this treatment, or the procedures and evaluations pre- and post- treatment.
31. Active participation in another clinical study that has not completed primary endpoint(s) evaluation or that clinically interferes with the endpoints in this study, or subject is planning to participate in such study prior to the completion of this study.