The study aim was to update the clinical analysis of hemodynamic performance, structural failure and survival in patients undergoing aortic valve replacement (AVR) with a composite aortic, aldehyde tanned, stentless porcine bioprosthesis.Between January 1990 and March 2001, 247 patients underwent AVR with aortic stentless valves. Patient demographic and clinical analysis included age, sex, valve lesion, valve size, pre- and postoperative NYHA class, hospital morbidity, mortality, operative data and duration of hospitalization.Mean patient age was 47.3 years; 71% of patients were males, and 45% had aortic insufficiency. The incidence of rheumatic heart disease requiring surgery was 41.7%. In 23% of patients surgery was indicated due to aortic stented bioprosthetic dysfunction. Preoperatively, 81% of patients were in NYHA classes III and IV. Mean follow up was 5.9+/-2.8 years (range: 1 month to 11.4 years); total follow up was 1,392 patient-years (98% complete). The valve size used was < or =25 mm in 75.3% of patients. The mean intensive care unit stay was 2.6 days; mean hospital stay was 10.7 days. Hospital mortality was 4.0% and late death 6.1%. There were no valve-related deaths. Postoperatively, the mean aortic effective orifice area (EOA) was 1.71 cm2, the mean peak transvalvular gradient 17.1 mmHg, and the mean transvalvular gradient 9.0 mmHg; the left ventricular mass index (g/m2) was 174 and 117 before and after surgery respectively. The rate of leaflet tissue degeneration was 0.9%, and seen as mild by echocardiographic follow up. Actuarial survival at almost 12 years was 91%, and freedom from reoperations was approximately 99%.Patients with aortic stentless valves have hemodynamic benefits seen as larger aortic EOA, low transvalvular gradients, satisfactory left ventricular remodeling with significant reduction of left ventricular mass, low complication rate, low reoperation rate, lower leaflet tissue degeneration rate, and no valve-related mortality. A longer follow up is required to confirm these benefits.