Bacteraemia after leadless pacemaker implantation

Background: Transvenous permanent pacemaker related infection is a severe condition associated with significant morbidity and mortality. Leadless pacemakers may be more resistant to bacterial seeding during bloodstream infection because of its small surface area and encapsulation in the right ventricle. This study reports the incidence and outcomes of bacteraemia in patients implanted with a Micra leadless pacemaker. We present 18F-FDG PET/CT findings obtained in a sub-group of patients. Methods: We report a retrospective cohort study of 155 patients who underwent a Micra TPS implant procedure at the University Hospitals of Leuven between July 2015 and July 2019. We identified the patients who developed an episode of bacteraemia, proved by ≥2 positive blood cultures. Results: Of the 155 patients, 15 patients presented an episode of bacteraemia at a median of 226 days (range: 3-1129) days after the implant procedure. Gram positive species accounted for 73.3% (n=11) of the bacteraemia including Staphylococcus (n=5), Enterococcus (n=3) and Streptococcus (n=3). The source of infection was identified in 9 patients (60%) including endocarditis in 4 patients, urinary tract in 3 patients, and skin in 2 patients. 18F-FDG PET/CT imaging performed in 6 patients did not show sign of infection around the leadless pacemaker. Bacteraemia was resolved in all patients after adequate antibiotherapy. Four patients died early during follow up. For all other patients, there were no recurrence of bacteraemia during a median follow up of 263 days (range 15-1134). Conclusion: In our small cohort, no leadless pacemaker endocarditis was observed among patients with bacteraemia.