Background and aim of the study: Sorin Bicarbon (SB) and Baxter Mira (BM) are almost identical bileaflet prostheses that share the same mechanical design, the only difference being in the sewing cuff. Hence, the long-term clinical performance of the two prostheses, when implanted in the aortic position, was evaluated in a combined population of patients.
Methods: Between January 1992 and December 2002, 714 patients (454 males, 260 females; mean age 60 +/- 13 years) underwent single aortic valve replacement with SB (n = 392) or BM (n = 322) valves. Concomitant non-valve procedures were performed in 64 patients (9.5%). Follow up was 95.7% complete, with a mean of 3.1 +/- 2.4 years.
Results: Operative mortality was 5.4% (39/714). Overall patient survival at five and 10 years was 89.3 +/- 1.4% and 77.7 +/- 4.3%, respectively; the linearized rate was 3.37% per pt-yr. Overall freedoms from complications at 10 years and valve group freedoms at four years were: thromboembolism 92.9 +/- 3.6% (SB 96.8 +/- 1.2% versus BM 98.4 +/- 0.8%); bleeding 94.5 +/- 3.5% (SB 97.5 +/- 1.1% versus BM 98.5 +/- 0.5%); nonstructural dysfunction 85.8 +/- 7.5% (SB 97.1 +/- 1.2% versus BM 99.3 +/- 0.07%); endocarditis 98.0 +/- 1.2% (SB 98.6 +/- 0.9% versus BM 100%); reoperation 95.1 +/- 3% (SB 98.6 +/- 0.9% versus BM 100%). Neither structural dysfunction nor valve thrombosis were observed. At the end of follow up, 78.3% of survivors were in NYHA class I, 17.3% in class II, 3.6% in class III, and 0.8% in class IV.
Conclusion: Experience with Sorin Bicarbon and Baxter Mira valve prostheses shows that these valves, when implanted in the aortic position, provide a satisfactory clinical performance, with low complication rates.