The outcome and risk factors over a 12-year follow up after implantation of 1,044 Mitroflow pericardial valves in the aortic position were analyzed. Valve size, patient age, preoperative status and previous and concomitant cardiac operations were considered as risk factors with regard to possible and potential valve-related complications and overall survival. Excellent long-term results were identified, notably in patients aged >70 years and with small aortic root diameters (³ 23 mm). Ten-year freedom rates for this patient group were 95.1 ± 1.3% for valve-related death, 90.8 ± 2.1% for explantation and 85.8 ± 4.6% for structural valve degeneration. The long-term durability and superior hemodynamics of Mitroflow pericardial valves can be combined by selecting patients with small aortic annuli aged ³ 70 years. In these patients, Mitroflow pericardial valves are equally durable as other widely used bioprosthetic valve prostheses.