Clinical Presentation, Timing, and Microbiology of CIED Infections: An Analysis of the WRAP-IT Trial.

Objectives: This study characterized the microbiology of major cardiac implantable electronic device (CIED) infections that occurred during the WRAP-IT (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial) study.

Background: The WRAP-IT study offers a unique opportunity for further understanding of the pathogens involved in major CIED infections in a prospective dataset, with implications for clinical practice and infection management.

Methods: A total of 6,800 patients randomized 1:1 to receive an antibacterial envelope or not (control subjects) were included in this analysis. Patient characteristics, infection manifestation (pocket vs. systemic), and infection microbiology were evaluated through all follow-up (36 months). Data were analyzed using Cox proportional hazards regression.

Results: A total of 3,371 patients received an envelope, and 3,429 patients were control subjects. Major CIED infection occurred in 32 patients who received an envelope and 51 control subjects (36-month Kaplan-Meier estimated event rate, 1.3% and 1.9%, respectively; p = 0.046). A 61% reduction in major pocket infection was observed within 12 months of the procedure in the envelope group (hazard ratio: 0.39, 95% confidence interval: 0.21 to 0.73; p = 0.003). Among 76 patients with major infections who had a sample taken, causative pathogens were identified in 47 patients. Staphylococcus species were the predominate pathogen (n = 31) and envelope use resulted in a 76% reduction in Staphylococcus-related pocket infections (n = 4 vs. 17; p = 0.010). Envelope use was not associated with delayed onset of pocket infections and did not affect the presentation of infections.

Conclusions: Antibacterial envelope use resulted in a significant reduction of major CIED pocket infections and was particularly effective against Staphylococcus species, the predominant cause of pocket infections. (Worldwide Randomized Antibiotic Envelope Infection Prevention Trial [WRAP-IT]; NCT02277990).