Aortic dissection is defined as a tear in the inner walls of the aorta that allows blood flow between the layers of the aortic wall, separating the vessel. A "Type B" aortic dissection occurs specifically in the descending thoracic aorta. Repair of the dissection via open surgery has historically yielded poor results, and the standard treatment is now thoracic endovascular aneurysm repair (TEVAR). In these minimally invasive procedures, a stent graft is inserted into the aorta via an artery in the groin area and positioned over the tear using X-rays for visualization. The stent obstructs blood flow between the walls of the aorta and induces a gradual remodeling process to repair the dissection. Medtronic's Valiant Navion Stent Graft System has already been approved by the FDA and is commercially available to patients as a treatment for a Type B aortic dissection. The DISSECT-N study is sponsored by Medtronic to further assess the safety and effectiveness of this system. It is an observational registry that introduces no additional testing or procedures to a patient's cardiovascular treatment; all research data will be taken from the subject's standard care information. Adults who intend to be treated with the Valiant Navion graft are eligible for participation, and they will be followed by the research team throughout the course of their procedure and for three years of follow-up.

You may be eligible for this study if you meet the following criteria:

• Conditions: Medical Research
• Age: 99 years or below
• Gender: All