The purpose of this clinical investigation is to evaluate the safety and efficacy of the Mitroflow DL valve when used to replace diseased or dysfunctional native or prosthetic aortic heart valves. The study will be conducted in a minimum of 15 centers in the United States. Patients will be evaluated at each of the following time intervals:preoperative, at implant, in the early postoperative period, at 1 year (between 11 and 13 months postoperatively), and annually for 8 years. The duration of the study is anticipated to be 8 years.
