TEST GROUP Inclusion Criteria

1. Patient is between the ages of 18 and 85.
2. Patient must be considered a candidate for elective surgical repair of the thoracic aortic aneurysm (i.e., low-to-moderate risk [categories 0, 1, and 2] per the modified SVS/AAVS scoring system at the time of implant; See Appendix A).
3. Females of childbearing age must have a negative pregnancy test within 7 days before treatment.

4. Patient has a:

   1. Fusiform focal TAA that is >5 cm in maximum diameter or is > 2 times the diameter of the adjacent native/non-aneurysmal aorta AND / OR
   2. Focal saccular TAA or penetrating atherosclerotic ulcer.
5. Thoracic aortic aneurysm must be at least 20 mm distal to the origin of the left common carotid artery and must be at least 20 mm proximal to the origin of the celiac artery.
6. Proximal and distal aortic non-aneurysmal neck diameter measurements must be > 18 mm and < 42 mm.
7. Patient's vascular anatomy is suitable for placement of the Talent Thoracic Stent Graft by having distinct proximal and distal aneurysm neck of >20 mm in length.
8. Thoracic aortic lesion is confirmed, at a minimum, by diagnostic contrast enhanced computerized tomography (CTA) with optional 3-D reconstruction, and/or contrast enhanced Magnetic Resonance Angiogram (MRA) obtained within the previous three (3) months prior to screening.
9. Patient must be able and willing to undergo follow-up imaging and examinations at 1, 6, and 12 month follow-up periods and annually for a total of five (5) years from initial implant. Lifelong follow-up by the physician is required after patients have completed the study.

TEST GROUP Exclusion Criteria

1. Planned placement of the COVERED (top edge of fabric) portion of the stent graft requires implant to occur in zones 0 or 1 (See Figure 5; Due to potential deployment difficulties, positioning the proximal edge of the bare spring in an overly angulated portion of the aorta is not recommended.)
2. The patient's access vessel (as determined by treating physician) precludes safe insertion of the delivery system.
3. Patient requires a planned aortic conduit.
4. Thoracic aneurysm with a contained rupture.
5. Patient has a connective tissue disease (e.g., Marfan's syndrome, medial degeneration).
6. Patient has a mycotic aneurysm or is suspected of having systemic infection.
7. Patient has received a previous stent and/or stent graft or previous surgical repair in the descending thoracic aortic area.
8. Patient requires treatment of an infra-renal aneurysm at the time of implant.
9. Patient has had previous surgical or endovascular treatment of an infra-renal aortic aneurysm.
10. Patient has a history of bleeding diathesis, coagulopathy, or refuses blood transfusions.
11. Patient has undergone a vascular interventional procedure or major surgery 30 days prior to enrollment. NOTE: This does not include planned procedures that are needed for safe and effective placement of the stent graft (i.e. carotid/subclavian transpositions, bypass procedures).
12. Patient requires a planned vascular interventional procedure or major surgery within 30 days of the implant procedure. NOTE: This does not include planned procedures that are needed for safe and effective placement of the stent graft (i.e. carotid/subclavian transpositions, bypass procedures).
13. Patient has had a recent (within three (3) months) cerebral vascular accident (CVA).
14. Patient is currently participating in an investigational drug or device clinical trial. (Patient must have completed the follow-up phase of any previous study at least 1 month prior to enrollment into this trial).
15. The patient has a known allergy or intolerance to the device components.
16. The patient has a known hypersensitivity or contraindication to anticoagulants or contrast media, which is not amenable to pre-treatment.
17. The presence of significant and/or circumferential aortic mural thrombus at either the proximal or distal attachment sites that would compromise fixation and seal of the implanted stent graft.
18. The patient has another medical condition, which may cause them to be non-compliant with the protocol, confound the data interpretation, or limited life expectancy of less than one year.