Cardiac surgery in patients with cardiac implantable electronic devices and risk of device infections: a nationwide nested case–control study

Purpose Cardiac surgery in patients with cardiac implantable electronic devices (CIEDs) has been associated with a higher risk of infective endocarditis, but how it influences risk of CIED-specific infections is not known. Our aim was to examine risk of systemic CIED infections after cardiac surgery in patients with CIEDs. Methods Based on data obtained from Danish administrative registries and the Danish Pacemaker and ICD Register, we conducted a case–control study nested within a nationwide cohort of patients who underwent a de novo CIED implantation in Denmark between 1998 and 2017. We defined cases as incident systemic CIED infections resulting in device system extraction. Controls were sampled 1:100 on time, age, sex and device type using risk set sampling. Exposure was defined as coronary artery bypass graft, or cardiac heart valve replacement or repair surgery. Results From a study cohort comprising 67,621 patients, we identified 170 cases and 16,788 controls. In the minimally adjusted model, the incidence rate ratio (IRR) for systemic CIED infection was 6.4 (95% confidence interval (CI) 3.8–10.7) with cardiac surgery, and after additional confounder adjustment, 5.4 (95% CI 3.2–9.2). IRRs were higher with restriction to heart valve replacement surgery (adjusted IRR 7.5, 95% CI 4.0–16.6), and when limiting our exposure time window to one year (adjusted IRR 10.1, 95% CI 4.5–22.3). Conclusion Cardiac surgery in patients with de novo CIEDs was associated with a high risk of systemic CIED infections. Highest risk was observed after heart valve replacement surgery and within the first year of surgery.