Inclusion Criteria:

1. Subject must be ≥ 18 years of age.
2. Subject is scheduled for elective, primary thoracic surgery involving the aortic valve, ascending aorta, or aortic arch on cardiopulmonary bypass.
3. Subject has an expected life expectancy> 6 months.
4. Subject is willing and able to comply with all aspects of the study including follow-up schedule.
5. Subject or authorized representative, has the ability to provide voluntary written informed consent.

Intra-operative Inclusion Criteria:

1. Subject is able to undergo an antegrade cardioplegia injection for evaluation of a leak at the aortic anastomotic site(s) during the procedure.
2. Following this injection, subject has a leaking site where a topical sealant/hemostatic agent may be used to control bleeding.

Exclusion Criteria:

1. Subject has Type A or other acute thoracic aortic dissection.
2. Subject has undergone prior thoracic surgery (open thoracotomy not including interventional cardiology procedures).
3. Subject is undergoing a planned concomitant procedure other than coronary artery bypass graft (CABG).
4. Subject has a previous organ transplant.
5. Subject has known or suspected preoperative coagulation disorder.
6. Subject is allergic to human thrombin or has a history of allergic reactions after application of human thrombin.
7. Subject is allergic to protamine.
8. Subject has a Left Ventricular Assist Device (LVAD) or planned to receive an LVAD.
9. Subject is undergoing emergency surgery.
10. Subject is in chronic renal failure.
11. Subject has a hematocrit < 21% pre-operatively.
12. Subject has a serum creatinine ≥2.5 mg/dl at baseline or is currently on dialysis.
13. Subject has a cardiac ejection fraction <25%.
14. Subject is scheduled for another cardiac surgery within 30 days of enrollment.
15. Subject has an active or latent infection which is systemic or at the intended surgery site.
16. Subject is immuno-compromised such as that resulting from chronic oral steroid use, chemotherapeutic agents, or immune deficiency disorders.
17. Subject is pregnant by a positive pregnancy test or has plans to become pregnant during the study period or is currently breast-feeding.
18. Subject is unwilling to receive blood products.
19. Subject has participated in another investigational research study within 30 days of enrollment.
20. In the opinion of the investigator, the subject has a clinical condition that would preclude the use of the study device, preclude the subject from completing the follow-up requirements, or would complicate the evaluation of this study.