Using serial echocardiography, we have evaluated the hemodynamic performance of the Medtronic Mosaicā bioprosthesis, a third-generation stented porcine valve which incorporates several features aimed at improving hemodynamics and preventing structural deterioration. Results have shown this device to be associated with low mean and peak gradients, and a significant reduction in left ventricular hypertrophy after aortic valve replacement with size 23 mm and 25 mm bioprostheses.