Objective : The choice of a valve substitute in young adults requires a decision balancing the risks of long-term anticoagulation and reoperation(s). We therefore analyzed the long-term risk and determinants of anticoagulation related events after mechanical aortic valve replacement.
Patients and Methods : Between December 1963 and January 1974, 249 patients survived a mechanical aortic valve replacement at our institution. Mean age was 41.8±12.4 years and 81% (n=202) were male. Ball valves were implanted in 24% (n=61) and disc valves in 76% (n=188). Patients were anticoagulated with vitamine K antagonists usually with antiplatelet drugs. A total of 4855 patient-years was available for analysis. Mean follow-up was 19.5±9.4 years and was 100% complete. Analyses were performed with Kaplan-Meier and multivariable Cox regression methods.
Results : One hundred and two patients had 1 anticoagulation related event and 58 patients had 2 events. Six patients had more than 5 events. Freedom from a first anticoagulation related event was 70.8±3.0%, 53.8±3.5%, 46.8±4.0% at 10, 20 and 30 years and for a second event it was 43.8±5.5%, 29.1±6.0% and 23.3±7.1%. Multivariate predictors for anticoagulation related complications were ball valve (O.R.=2.9), postoperative endocarditis (O.R.=2.2) and any surgery (O.R.=2.2). The incidence of events was highest the first 5 years postoperatively.
Conclusion : The risk of adverse events is highest the first 5 postoperative years. Once an event has occurred, the risk for a second event is increased. The incidence and frequency of events is substantial and should be considered in the choice of a valve substitute.