Hemodynamic assessment of the Medtronic Mosaic® bioprosthesis in the aortic position

Background and aim of the study: The Medtronic Mosaic® bioprosthesis (MMB) is a newly developed tissue valve which incorporates several features such as a low-profile semi-flexible stent, zero-pressure tissue fixation, and anti-mineralization pretreatment with α-amino oleic acid aimed to improve hemodynamics and prevent structural deterioration. Methods: Between November 1995 to June 1999, 62 patients underwent aortic valve replacement (AVR) with the MMB; 41 of these who reached the one-year follow up interval and who had isolated AVR without any concomitant procedure with size 23 mm and 25 mm MMB were evaluated by serial echocardiography after three, six and 12 months. Results: For size 23 mm valves, mean and peak gradients were 12 ± 3 and 21 ± 6 mmHg at 3 months, 12 ± 3 and 20 ± 5 mmHg at 6 months, and 12 ± 4 and 20 ± 6 mmHg at 12 months. For size 25 mm valves, mean and peak gradients were 13 ± 2 and 22 ± 4 mmHg at 3 months, 12 ± 3 and 21 ± 5 mmHg at 6 months, and 12 ± 4 and 22 ± 6 mmHg at 12 months. In patients with 23 mm MMB, left ventricular mass index (LVMi) was reduced from 181 ± 34 g/m2 before surgery to 158 ± 32, 150 ± 28 and 140 ± 25 g/m2 at 3, 6 and 12 months after AVR (p <0.001); in patients with 25 mm MMB, LVMi was reduced from 182 ± 28 g/m2 before surgery to 165 ± 25, 156 ± 24 and 146 ± 19 g/m2 at 3, 6 and 12 months after AVR (p <0.001). Conclusion: Our results indicate that MMB is associated with low mean and peak gradients and significant reduction in LVMi throughout the postoperative period. Thus, the MMB appears to be an excellent cardiac valve substitute in elderly subjects who require AVR.