Clinical profile, microbiology and outcomes in infective endocarditis treated with aortic valve replacement: a multicenter case-control study.

Background: Aortic valve infective endocarditis (IE) is associated with significant morbidity and mortality. We aimed to describe the clinical profile, risk factors and predictors of short- and long-term mortality in patients with aortic valve IE treated with aortic valve replacement (AVR) compared with a control group undergoing AVR for non-infectious valvular heart disease.

Methods: Between January 2008 and December 2013, a total of 170 cases with IE treated with AVR (exposed cohort) and 677 randomly selected non-infectious AVR-treated patients with degenerative aortic valve disease (controls) were recruited from three tertiary hospitals with cardiothoracic facilities across Scandinavia. Crude and adjusted hazard ratios (HR) were estimated using Cox regression models.

Results: The mean age of the IE cohort was 58.5 ± 15.1 years (80.0% men). During a mean follow-up of 7.8 years (IQR 5.1-10.8 years), 373 (44.0%) deaths occurred: 81 (47.6%) in the IE group and 292 (43.1%) among controls. Independent risk factors associated with IE were male gender, previous heart surgery, underweight, positive hepatitis C serology, renal failure, previous wound infection and dental treatment (all p < 0.05). IE was associated with an increased risk of both short-term (≤ 30 days) (HR 2.86, [1.36-5.98], p = 0.005) and long-term mortality (HR 2.03, [1.43-2.88], p < 0.001). In patients with IE, chronic obstructive pulmonary disease (HR 2.13), underweight (HR 4.47), renal failure (HR 2.05), concomitant mitral valve involvement (HR 2.37) and mediastinitis (HR 3.98) were independent predictors of long-term mortality. Staphylococcus aureus was the most prevalent microbe (21.8%) and associated with a 5.2-fold increased risk of early mortality, while enterococci were associated with the risk of long-term mortality (HR 1.78).

Conclusions: In this multicenter case-control study, IE was associated with an increased risk of both short- and long-term mortality compared to controls. Efforts should be made to identify, and timely treat modifiable risk factors associated with contracting IE, and mitigate the predictors of poor survival in IE.