Randomized Trial of Stand-Alone Use of the Antimicrobial Envelope in High-Risk Cardiac Device Patients

Background: Cardiac implantable electronic device (CIED) infection has a high mortality. Previous investigations showed reduced postoperative infections using skin preparation with chlorhexidine, preoperative intravenous antibiotics, and a TYRX-a antibacterial envelope. The additional benefit of antibiotic pocket wash and postoperative antibiotics has not been systematically studied.

Methods: The ENVELOPE trial (A Randomized trial of Stand-Alone Use of the Antimicrobial Envelope in High-Risk Cardiac Device Patients) was a prospective, multicenter, randomized, controlled trial enrolling patients undergoing CIED procedures with ≥2 risk factors for infection. The control arm received standard chlorhexidine skin preparation, intravenous antibiotics, and the TYRX-a antibiotic envelope. The study arm received pocket wash (500 mL antibiotic solution) and postoperative antibiotics for 3 days along with the prophylactic control measures. The primary end point was CIED infection and system removal at 6 months.

Results: One thousand ten subjects (505 per arm) were enrolled and randomized. Patients were seen in person for a wound check with digital photo 2 weeks postimplant and at 3 and 6 months. CIED infection rate was low in both groups (1.0% control arm and 1.2% study arm, P=0.74). In the 11 subjects with infection and system removal, the time to study end point was 107±92 days with a PADIT (Prevention of Arrhythmia Device Infection Trial) score of 7.4 and a 64% 1-year mortality. Prior history of CIED infection independently predicted CIED system removal at 6 months in all subjects (odds ratio, 9.77, P=0.004). Of 11 infections requiring system removal, 5 were in the setting of pocket hematoma.

Conclusions: The use of antibiotic pocket irrigation and postoperative oral antibiotics provides no additional benefit to the prophylactic measures of chlorhexidine skin preparation, preoperative intravenous antibiotics, and an antibiotic envelope in reducing CIED infection. Postoperative hematoma is a major risk factor for infection, driven by the use of antiplatelet and anticoagulant medications. The strongest predictor of CIED removal at 6 months, regardless of intervention, was prior CIED infection.

Registration: URL: https://www.

Clinicaltrials: gov; Unique identifier: NCT02809131.