Hemodynamic performance of the CarboMedics heart valve in the aortic position and its clinical impacts were investigated in 126 consecutive patients. The actuarial survival rates of patients who had undergone isolated aortic valve replacement and concomitant aortic and mitral valve replacement were 82.6+/-5.7% and 71.0+/-9.2% at 8 years, respectively. Morbid events were rare, and almost all late survivors were free from evident cardiac symptoms regardless of the valve size. Echocardiography revealed suboptimal transvalvular pressure gradients and effective orifice areas of 19 mm and 21 mm valves. However, relief of the left ventricular overload and improvement of the clinical symptoms as well as cardiac function were comparable to those of patients with larger valves. Valve function measured by echocardiography did not show significant correlation to late outcome. Good results can be expected even in the presence of echocardiographic data such as peak pressure gradient over 40 mmHg, effective orifice area less than 1.0 cm(2), and effective orifice area index less than 0.7 cm(2)/m(2).