Mitral valve replacement or repair and long-term risk of infective endocarditis: a Danish nationwide study

BACKGROUND AND AIMS: Infective endocarditis (IE) after mitral valve (MV) interventions is a serious complication. However, information on the long-term risk of first-time IE after MV replacement or repair is lacking. The 10-year incidence of first-time IE was examined in patients undergoing MV replacement or repair, compared with those at moderate risk of IE. METHODS: Using Danish nationwide registries (2000-2020), the study population included patients undergoing isolated MV replacement or repair and patients at moderate risk of IE. The moderate-risk group included cardiac implantable electronic devices, congenital heart valve anomalies, hypertrophic cardiomyopathy, rheumatic heart diseases, and non-rheumatic degenerative valve diseases. The Aalen-Johansen estimator and cause-specific Cox regression models were used to determine the 10-year comparative incidences of IE. RESULTS: The study population included 1220 patients undergoing MV replacement, 3239 undergoing MV repair, and 209 517 at moderate risk of IE. The 10-year cumulative incidences of IE were 6.1% [95% confidence interval (CI) 4.8%-7.7%] for MV replacement, 1.6% (95% CI 1.1%-2.1%) for MV repair, and 1.7% (95% CI 1.6%-1.7%) for the moderate-risk group. Compared with the moderate-risk group, after multivariable adjustment, MV replacement was associated with a higher 10-year IE rate (hazard ratio 3.52, 95% CI 2.73-4.52), whereas MV repair was not associated with IE (hazard ratio 0.76, 95% CI 0.56-1.04). CONCLUSIONS: In this nationwide study, MV replacement was associated with a 3.5-fold increased 10-year IE rate, whereas MV repair was not significantly associated with IE, compared with patients at moderate risk of IE. These findings highlight the need for further investigation into preventive measures, including targeted antibiotic prophylaxis.