Experimental: Thoracoabdominal Aortic Aneurysm Arm

The TAAA study arm will include patients treated by endovascular aortic repair of thoracoabdominal aortic aneurysms (Extent I to IV) using either an off-the-shelf Zenith t-Branch or patient-specific stent-graft with a combination of fenestrations and/or branches. The graft includes 1 to 5 small holes (fenestrations) or cuffs (side branches) . These small holes or branches are the investigational part of this research study. The arteries to the liver, intestine, and kidneys will be have a stent (small tubular stainless steel structures) to help keep the arteries open and aligned with the fenestrations or branches.

Experimental: Aortic Arch Aneurysm Arm

Aortic Arch study arm will include patients with aortic arch aneurysms treated by Patient-specific stent-grafts with one to three inner branches or a scallop. The study will include patients with thoracoabdominal and/or aortic arch aneurysms due to degenerative aneurysms or chronic aortic dissections. The stent-graft design for this study will be individually selected based on anatomy at the discretion of the principal investigator, including an off-the-shelf stent-graft (t-Branch stent-graft) or patient-specific stent-graft with a combination of fenestrations and/or branches.