Antibiotic Prophylaxis for Pacemaker Implantation

ABSTRACTS & COMMENTARY

Synopsis: S. schleiferi is a possible cause of pacemaker-related infection, with a high incidence of infection if the organism is present at the time of implant.

Sources: Da Costa A, et al. Circulation 1998;97: 1796-1801; Da Costa A, et al. Circulation 1998;97: 1791-1795.

The need for prophylactic antibiotics with pacemaker or defibrillator implantation remains controversial. Da Costa and associates reviewed the literature on this topic and identified seven randomized clinical trials and examined the effect of systemic antibiotics on pacemaker-related infections. These studies included data from 2023 patients equally randomized between prophylactic antibiotic therapy and no therapy. The groups were similar with respect to age, gender, mode of pacing, and risk factors for infection. End points differed between studies, with two studies counting only infections that required reoperation whereas the others included all infections. The prophylactic antibiotic chosen was either a penicillinase-resistant penicillin or a cephalosporin.

The incidence of infection ranged from 0% to 12% in the individual studies. Overall, the incidence was 5/1011 (0.5%) among the antibiotic-treated patients and 37/1012 (3.7%) in the control patients. There was a consistent treatment effect across studies with an overall odds ratio of 0.256 (0.5%; CI, 0.10-0.656). Da Costa et al conclude that these data support the use of prophylactic antibiotics at the time of pacemaker insertion to prevent short-term pocket infection, skin erosion, or septicemia.

In a companion article that precedes the meta-analysis, Da Costa et al also reviewed the incidence of pacemaker-related infections at their own institution. They prospectively collected implantation site and pocket cultures from 103 consecutive patients undergoing pacemaker implant. Positive cultures were obtained from 88% of the skin samples, 48% of the pocket samples before insertion, and 37% of the pocket samples at the end of surgery. Staphylococcus species were the organisms most commonly identified. During follow-up of 1-24 months, four patients developed infections at the pacemaker site at one, four, 10, and 16 months after implant. S. schleiferi caused two infections, but it had been isolated from only five cultures. S. aureus and S. epidermidis were responsible for one infection each. The S. schleiferi infections were caused by the same strains of the organism that were isolated at implants, whereas the latter two infections were caused by strains not present at implant. Da Costa et al conclude that S. schleiferi is a possible cause of pacemaker-related infection, with a high incidence of infection if the organism is present at the time of implant.

COMMENT BY JOHN P. DiMARCO, MD, PhD

These two papers focus on the possible infectious complications of pacemaker insertion. Implantable cardioverter defibrillators (ICD) are now usually implanted using similar techniques. Because of the larger device and the need for more complex intraoperative testing, it is likely that infection complications will be more common after ICD implantation. Infection of either a pacemaker or ICD is often a life-threatening illness due to the effects of sepsis, loss of arrhythmia control, or complications from device explant. The meta-analysis confirms the wisdom of the common practice of prescribing antibiotics around the time of implant. Unfortunately, the meta-analysis does not report either the cost or side effects of such therapy. However, the antibiotic regimens reported should be expected to be relatively inexpensive and safe. Therefore, the use of prophylactic antibiotics in addition to scrupulous attention to appropriate surgical techniques seems justifiable.

The other paper raises some further interesting questions. Da Costa et al identified S. schleiferi as the cause of two of the four infections in their series. They did not use routine antibiotics, but none of the antibiotic regimens tested in the studies included in the meta-analysis would be expected to cover this organism reliably. If other centers also note the same organism as a frequent cause of device-related infection, changes in the antibiotics used for prophylaxis may be necessary. This could cause concern regarding cost, side effects, and development of antibiotic-resistant strains.