The purpose of this study is to evaluate the safety and effectiveness performance of the Zenith® Dissection Endovascular System in the treatment of aortic dissections involving the descending thoracic aorta.

The Zenith® Thoracic Dissection Study is a clinical trial to study the safety and effectiveness of the Zenith® Dissection Endovascular System in the treatment of dissections (length-wise tear) of the descending thoracic aorta. The Zenith® Dissection Endovascular System is comprised of the Zenith TX2® TAA Endovascular Graft and the Zenith® Dissection Endovascular Stent. Instead of making a large incision in the chest, the physician makes a small incision near each hip to insert, and guides the graft and the dissection stent into place in the aorta.

Inclusion Criteria:

• Branch vessel obstruction/compromise
• Peri-aortic effusion/hematoma
• Resistant hypertension
• Persistent pain/symptoms
• Transaortic growth greater than or equal to 5 mm within 3 months (or transaortic diameter greater than or equal to 40 mm)

Exclusion Criteria:

• Age less than 18 years
• Frank rupture
• Diagnosed or suspected congenital degenerative connective tissue disease
• Systemic infection
• Untreatable reaction to contrast
• Surgical/endovascular AAA repair within 30 days
• Previous placement of thoracic endovascular graft
• Prior repair of descending thoracic aorta
• Interventional/open procedures within 30 days
• Onset of symptoms > 3 months