Medtronic mosaic porcine bioprosthesis: investigational center experience to six years.

BACKGROUND AND AIM OF THE STUDY: The findings of this single-center experience with the Medtronic Mosaic porcine bioprosthesis were evaluated to determine the clinical performance of the valve. METHODS: Between 1994 and 2000, a total of 657 patients was implanted with the prosthesis. Aortic valve replacement (AVR) was performed in 415 patients (mean age 70.5+/-10.7 years; range: 26-89 years) and mitral valve replacement (MVR) in 242 patients (mean age 70.5+/-9.5 years; range: 19-86 years). Concomitant coronary artery bypass (CAB) was performed in 51.1% and 46.7% of AVR and MVR patients, respectively. The majority of patients were aged over 70 years (59.8% AVR, 58.7% MVR). RESULTS: Survival at six years was 73.0+/-2.4% after AVR, and 74.0+/-5% after MVR (p = NS). Actual freedom from valve-related mortality at six years was 98+/-1% for AVR and 96+/-1% for MVR; freedom from overall thromboembolism (TE) was 86+/-3% for AVR and 89+/-2% for MVR. After AVR, 42 thromboembolic events occurred in 39 patients (23 minor; 14 major; three reversible ischemic neurologic deficits (RIND); two thrombosis). After AVR, the late TE rate was 2.1% per pt-yr, and the major rate 0.6% per pt-yr (exclusive of thrombosis). The overall TE rate after AVR was 2.9% per pt-yr (major rate 1% per pt-yr). After MVR, 25 events occurred in 24 patients (10 minor; eight major; five RIND; two thrombosis). After MVR, the late TE rate was 2.6% per pt-yr, and the major rate 0.7% per pt-yr (exclusive of thrombosis). The overall TE rate after MVR was 3.5% per pt-yr (major rate 1.1% per pt-yr). There were four cases of structural valve deterioration (SVD) (two each after AVR and MVR). Reoperation was performed in three of four cases of thrombosis, and in two of four cases of SVD. CONCLUSION: The Medtronic Mosaic porcine bioprosthesis is safe and effective. The rate of SVD after six years was low, being zero in the aortic position of patients aged >60 years, and zero also in the mitral position of patients aged <60 years. The incidence of early and late thromboembolism was contributed to by the advanced age of the patient population.