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Risk of cardiac implantable electronic device (CIED) infection and resulting mortality hinged on the timing and extent of infection, which may ultimately come down to the type of procedure that the patient had undergone, according to prospective data from the PADIT study.

The bulk of the 177 pacemaker and implantable cardioverter-defibrillator (ICD) infections in the trial occurred within the first 3 months of device placement, at a rate of 0.21% per month, dropping precipitously thereafter. This trend was consistent for localized and systemic infections alike and did not depend on prophylactic antibiotic type, CIED procedure type, or calculated infection risk, reported Andrew Krahn, MD, of Heart Rhythm Vancouver in British Columbia, and colleagues of the PADIT (Prevention of Arrhythmia Device Infection Trial) collaboration spanning 28 centers in Canada and the Netherlands.

Yet the risk of all-cause mortality from CIED infection differed according to the timing and extent of infection, the researchers suggested in their paper in .

Whereas people harboring early (within 3 months) localized infections were not at higher risk for all-cause mortality at 30 days (zero deaths; adjusted HR 0.64 compared with patients who did not develop CIED infection, 95% CI 0.20-1.98), death rates were excessively high for patients with:

• Early systemic infections (8.9%; adjusted HR 2.88, 95% CI, 1.48-5.61)

• Delayed (between 3 and 12 months) localized infections (8.8%; adjusted HR 3.57, 95% CI 1.33-9.57)

• Delayed systemic infections (21.7%; adjusted HR 9.30, 95% CI 3.82-22.65)

"Preventive measures should be considered for patients who are at risk for early systemic infections, such as removing unnecessary central lines, ensuring appropriate preprocedural antibiotics, awaiting clearance of blood cultures for those with bacteremia before CIED implant, and judiciously considering the use of antibiotic-eluting envelopes," Krahn and colleagues said.

They also urged education of patients to monitor signs of localized infection and systemic infection after implant and education of other healthcare providers in the early detection and referral of patients with CIED infections.

By timing, 67% of CIED infections in PADIT were early cases caught within the first 3 months, with the other 33% occurring between 3 and 12 months.

Infections were localized in 62% of cases and systemic in the remaining 38%. Individuals with localized CIED infections were more likely to have undergone a pocket or lead revision procedure. In contrast, peers with systemic CIED infections collectively tended to have more underlying diabetes and had disproportionately more de novo pacemaker implants.

Nearly three-quarters of CIED infections were related to generator replacement or pocket or lead revision.

"This study emphasizes that different management strategies are needed for patients with existing devices versus those patients having a new device placed," said electrophysiologist Sean Pokorney, MD, MBA, of Duke University School of Medicine in Durham, North Carolina. "Most of the device infections were seen in patients with generator replacements or revisions, reaffirming that this is a high-risk population."

Pokorney, who was not involved with the study, suggested use of the Tyrx pouch to prevent infection in higher-risk patients. He also advised closer outpatient follow-up of those who had undergone generator change-out or revision. "This could include having patients take pictures of their device site on a weekly basis and upload those pictures into the electronic health record for monitoring," he explained.

In current practice, CIED patients are routinely seen in clinic 2-4 weeks after a device placement for a wound check. They check in again 3-6 months later for routine follow-up care, Pokorney told 麻豆传媒.

Krahn's team reported that when CIED infection was detected in PADIT participants, treatment was directed by the implant cardiologist. This included a course of both IV and oral antibiotics along with consideration of device extraction -- the latter of which turned out to be associated with improved survival.

"Although the numbers are small, patients who did not undergo a surgical intervention had an approximately 4-fold increase in 30-day mortality, supporting the usual recommendation to remove all hardware when possible and suggesting a possible association between treatment and mortality," the investigators noted.

"Early identification of generator change-out patients and/or revision patients who develop infection is critical," Pokorney emphasized. "Previous studies have shown that earlier identification and complete hardware removal with lead extraction decreases mortality in these patients."

The present prospective cohort study was based on the PADIT cluster-crossover randomized trial originally designed to test incremental antimicrobial treatment vs conventional treatment in the prevention of CIED infection.

There were nearly 20,000 participants who underwent CIED procedures in the study, for whom the cumulative incidence of infection was 0.6%, 0.7%, and 0.9% within 3, 6, and 12 months, respectively. The 177 who developed a CIED infection averaged 69 years old and 75% were men.

Krahn and co-authors acknowledged that their observational study lacked important information on factors such as the use of central venous lines or in-dwelling catheters for CIED recipients.

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