Risk factors associated with early-versus late-onset implantable cardioverter-defibrillator infections

Aims The infection rates of implantable cardioverterdefibrillators systems (ICDs) are higher than that of permanent pacemaker. Risk factors associated with ICD infection have not been characterized and are the subject of the current investigation. Methods All patients who had an ICD implanted at Mayo Clinic Rochester between 1991 and 2008 were retrospectively reviewed. Each case of ICD infection was matched with two non-infected controls. Cases of ICD infection were further stratified by early- (≤6 months) versus late-onset (>6 months) infection. Multivariable analysis was performed to identify significant risk factors for ICD infection. Results Sixty-eight patients with ICD infection and 136 matched controls met the inclusion criteria. Thirty-five cases presented with early-onset infection and 33 had late-onset device infection. Staphylococcal species were the most common pathogens in both groups of patients. Patients with early-onset infection were more likely to present with generator pocket infection (p=0.02). Patients with multiple comorbid conditions (high Charlson index) tended to have longer hospital stay during implantation admission (p=0.009). In a multivariable logistic regression model, the presence of epicardial leads (odds ratio (OR)=9.7, p=0.03) and postoperative complications at the generator pocket (OR=27.2, p<0.001) were significant risk factors for early-onset ICD infection, whereas longer duration of hospitalization at the time of implantation (2 days versus 1 day: OR=33.1, p<0.001; ≥3 days versus 1 day: OR=49.0, p<0.001) and chronic obstructive pulmonary disease (OR=9.8, p=0.02) were associated with late-onset infections. Conclusions Our study findings suggest that risk factors associated with early- and late-onset ICD infection are different. While circumstances that may increase the chances of pocket contamination in the perioperative period are more likely to be associated with early-onset ICD infection, overall poor health of the host may increase the likelihood of late-onset ICD infection. These factors should be considered when developing strategies to minimize risk of device infection.