THE SPANISH MONOSTRUT STUDY-GROUP - A 10-YEAR EXPERIENCE WITH 8,599 IMPLANTS

Background. The Monostrut valve is a pyrolytic carbon, tilting-disc pr osthesis with no welds. After the first implantation in Spain in May 1 983, the Spanish Monostrut Study Group was established to evaluate pro spectively the performance of the valve using uniform protocols. Metho ds. During a 10-year period, 8,599 Monostrut valves were implanted in 7,317 patients in 22 centers. Mean age was 53.3 +/- 11 years. Of the t otal group, 3,229 underwent aortic valve replacement, 2,806 had mitral valve replacement, and 1,282 had double valve replacement. Follow-up was 96% complete, with a mean period of 4.3 years and a total of 29,15 5 patient-years. Results. The operative mortality rate was 7.2%. The 1 0-year probability of freedom from valve-related complications and lin earized rates (event/100 patient-years in parentheses) were as follows : structural deterioration, 100% (0); nonstructural dysfunction, 96% /- 0.5% (0.51); thromboembolism, 82.9% +/- 1.5% (1.32); anticoagulant- related hemorrhage, 87.6% +/- 1.4% (0.98); and prosthetic valve endoca rditis, 96.1% +/- 0.5% (0.48). There were five obstructive valve throm boses (0.017/100 patient-years). Actuarial freedom from reoperation wa s 95% +/- 0.5% at 10 years. Actuarial freedom from all valve-related m orbidity was 70.2% +/- 1.6%; freedom from all valve-related morbidity and mortality (including operative and sudden deaths) was 62.6% +/- 2% (70.1% +/- 2% for aortic valve replacement, 56.9% +/- 2% for mitral v alve replacement, iand and 59.8% +/- 3% for double valve replacement; p < 0.0001). Clinically, 5,988 patients (94%) are in New York Heart As sociation class I-II. Conclusions. The Monostrut valve has shown no st ructural failures and a low rate of valve-related complications over a 10-year period in a large patient population.