Healthcare exposures and associated risk of endocarditis after open-heart cardiac valve surgery

Background Infective endocarditis (IE) following cardiac valve surgery is associated with high morbidity and mortality. Data on the impact of iatrogenic healthcare exposures on this risk are sparse. This study aimed to investigate risk factors including healthcare exposures for post open-heart cardiac valve surgery endocarditis (PVE). Methods In this population-linkage cohort study, 23,720 patients who had their first cardiac valve surgery between 2001 and 2017 were identified from an Australian state-wide hospital-admission database and followed-up to 31 December 2018. Risk factors for PVE were identified from multivariable Cox regression analysis and verified using a case-crossover design sensitivity analysis. Results In 23,720 study participants (median age 73, 63% male), the cumulative incidence of PVE 15 years after cardiac valve surgery was 7.8% (95% CI 7.3–8.3%). Thirty-seven percent of PVE was healthcare-associated, which included red cell transfusions (16% of healthcare exposures) and coronary angiograms (7%). The risk of PVE was elevated for 90 days after red cell transfusion (HR = 3.4, 95% CI 2.1–5.4), coronary angiogram (HR = 4.0, 95% CI 2.3–7.0), and healthcare exposures in general (HR = 4.0, 95% CI 3.3–4.8) (all p < 0.001). Sensitivity analysis confirmed red cell transfusion (odds ratio [OR] = 3.9, 95% CI 1.8–8.1) and coronary angiogram (OR = 2.6, 95% CI 1.5–4.6) (both p < 0.001) were associated with PVE. Six-month mortality after PVE was 24% and was higher for healthcare-associated PVE than for non-healthcare-associated PVE (HR = 1.3, 95% CI 1.1–1.5, p = 0.002). Conclusions The risk of PVE is significantly higher for 90 days after healthcare exposures and associated with high mortality.