ATS 3f(r) Aortic Bioprosthesis Model 1000, 19mm

Inclusion Criteria: * This patient requires isolated aortic valve replacement with or without concomitant procedures such as coronary artery bypass or another valve reconstruction. (The three remaining valves must be of native tissue). * This patient is sufficiently ill to warrant replacement of his/her diseased natural or prosthetic valve, based on standard cardiovascular diagnostic workups. * This patient is in satisfactory condition, based on the physical exam and investigator's experience, to be an average or better operative risk, (i.e., likely to survive one year postoperatively). * This patient is geographically stable and willing to return to the implant center for follow-up visits. * This patient has been adequately informed and consents to his/her participation in the clinical study, and of what will be required of him/her, in order to comply with the protocol. Exclusion Criteria: * This patient is twenty (20) or less than twenty years of age. * This patient has a non-cardiac major or progressive disease, which in the investigator's experience produces an unacceptable increased risk to the patient, or results in a life expectancy of less than 12 months. * This patient is an intravenous drug and/or alcohol abuser. * This female patient is pregnant (urine HCG test result positive), or lactating. * This patient presents with active endocarditis. * This patient presents with congenital bicuspid aortic anatomy. * This patient has a previously implanted prosthetic valve that is not being replaced by a study valve. * This patient requires mitral, tricuspid or pulmonic valve replacement. * This patient is participating in concomitant research studies of investigational products. * This patient will not agree to return to the implant center for the required number of follow-up visits or is geographically unavailable for follow-up.