Long-term Follow-up of Patients with Infective Endocarditis in a Tertiary Referral Center

Background: Infective endocarditis (IE) remains a severe disease with high mortality. Most studies report on short-term outcome while real world long-term outcome data are scarce. This study reports reinfection rates and mortality data during long-term follow-up.

Methods: A total of 270 patients meeting the modified Duke criteria for definite IE admitted to a tertiary care center between July 2000 and June 2007 were analyzed retrospectively. Early reinfection was defined as a new IE episode within 6 months; late reinfection as a new IE episode beyond 6 months follow-up.

Results: Median follow-up was 8.5 years. Early reinfection occurred in 10 patients (3.7%), late reinfection in 18 patients (6.7%). Staphylococci (39.7%) were the most frequent causative microorganisms, followed by Streptococci (30.0%) and Enterococci (17.8%). Independent predictors of any reinfection were heart failure (HR 3.02, 95% CI 1.42-6.41), peripheral embolization (HR 4.00, 95% CI 1.58-10.17) and implanted pacemakers (HR 3.43, 95% CI 1.25-9.36). Survival rates were 71.1%, 55.2% and 43.3% at respectively 1-, 5- and 10-years follow-up. Independent predictors for mortality were age (HR 1.03, 95% CI 1.01-1.04), diabetes mellitus (HR 2.24, 95% CI 1.46-3.45), hemodialysis (HR 2.70, 95% CI 1.37-5.29), heart failure (HR 1.64, 95% CI 1.19-2.26), stroke (HR 1.73, 95% CI 1.18-2.52), antimicrobial treatment despite surgical indication (HR 5.53, 95% CI 3.59-8.49) and non-Streptococci causative microorganisms (HR 1.84, 95% CI 1.28-2.64).

Conclusions: Contemporary mortality rates of infective endocarditis remain high, irrespective of reinfection. Heart failure, peripheral embolization and presence of a pacemaker were predictors of reinfection.