Objective: A follow-up study was performed to assess long-term survival, valve-related complications, and pregnancy outcomes in young rheumatic women undergoing isolated mitral mechanical replacement. The influence of prosthetic type on outcomes was also investigated.
Methods: Between 1975 and 2003, 267 isolated mitral mechanical prostheses were implanted. Follow-up reached 3707.8 patient-years.
Results: Actuarial survival at 1, 5, 10, 15, 20, and 25 years was 97% +/- 0.01%, 90.4% +/- 0.017%, 85.3% +/- 0.023%, 82.3% +/- 0.025%, 71.7% +/- 0.036%, and 70.2% +/- 0.038%, respectively. At multivariate analysis, atrial fibrillation at follow-up was identified as an independent risk factor for late mortality, whereas left ventricular ejection fraction at 12 postoperative months proved to be a protective factor. Freedom from thromboembolism at 1, 5, 10, 15, 20, and 25 years was 98.1% +/- 0.01%, 94.1% +/- 0.015%, 89.1% +/- 0.021%, 85.9% +/- 0.025%, 81.1% +/- 0.031%, and 75.3% +/- 0.063%, respectively. Atrial fibrillation and Carbomedics device were significantly associated with an increase in thromboembolic events. Freedom from reoperation at 1, 5, 10, 15, 20, and 25 years was 99.2% +/- 0.005%, 95% +/- 0.014%, 91.6% +/- 0.018%, 88.6% +/- 0.022%, and 85.7% +/- 0.041%. Type of prosthesis (tilting disc) was identified as a predictor of reoperation. At the end of the study, 208 patients were still alive: 94.7% were in New York Heart Association class I or II. When receiving warfarin therapy, no patient undertaking pregnancy (n = 35) experienced adverse cardiac or valve-related events. Fetal events were significantly less frequent with a daily warfarin dose less than 5 mg.
Conclusions: Mechanical devices provided excellent performance, safety, and durability. The prognostic role of left ventricular function and atrial fibrillation overwhelmed any differences that might exist between different prosthetic designs. Pregnancies entail virtually no maternal risk and predictable fetal complications.