Medtronic mosaic porcine bioprosthesis: midterm investigational trial results

Background. The midterm clinical and hemodynamic performance of the Medtronic Mosaic porcine bioprosthesis was evaluated in a regulatory trial. Methods. In nine Canadian centers, 802 bioprostheses (560 aortic and 242 mitral) were implanted between September 1994 and April 1999 in patients with a mean age of 70 years. Results. Survival for aortic valve replacement at 4 years was 84.4% ± 3.1%. Freedom from valve-related or unexplained death was 95.6% ± 1.9%; structural valve deterioration, 100.0%; reoperation, 96.2% ± 1.7%; major thromboembolism, 96.1% ± 1.8%; and major antithrombotic-related hemorrhage, 96.4% ±1.7%. Echocardiographic derived mean systolic gradient was 13.4 mm Hg at 4 years with an indexed effective orifice area of 0.7 to 0.8 cm2/m2. A significant decrease in left ventricular mass was shown over time in all valve sizes. Survival for mitral valve replacement at 4 years was 79.2% ± 6.8%. Freedom from valve-related or unexplained death was 96.5% ± 3.4%; structural valve deterioration, 100%; reoperation, 97.0% ± 3.2%; major thromboembolism, 95.7% ± 3.8%; and major antithrombotic-related hemorrhage, 95.0% ± 4.2%. Echocardiographically measured averaged mean diastolic gradient was 4.5 mm Hg. Conclusions. The Medtronic Mosaic bioprosthesis is safe and effective in both the aortic and mitral positions. The valve has low gradients in both positions and excellent left ventricular mass regression in the patients with aortic valve replacement.