Predictors of Cardiac Implantable Electronic Device Infection in Patients with Staphylococcus Aureus Bacteremia
Staphylococcus aureus bacteremia (SAB) is commonly associated with cardiac implantable electronic device infection (CIED-I). This usually requires explantation of the device. In cases of SAB in the presence of CIED that is not obviously infected (after examination of the pocket and transesophageal echocardiogram), decision about device removal is less clear. Predicting CIED-I in those cases would be helpful.
This case-control study included all adults admitted to the University of Kansas Medical Center with SAB in the presence of a CIED between 1/1/2007 and 12/31/2012, using ICD 9 codes, CIED registry, and microbiology database. Cases had device infection evidenced by pocket infection or CIED related endocarditis; controls did not, over a 12 weeks follow up period. Clinical predictors of CIED-I were evaluated using logistic regression. Mortality was evaluated at 30 and 365 days.
We identified 64 patients with CIED who had 70 separate episodes of SAB during the study period. Of all 70 episodes of SAB, 74.3% were in males, 74.3% were in white, and mean age was 65.3 years. MRSA accounted for 48.6% of SAB. There were 31 episodes involving the device (44.3%, cases) and 39 SAB without CIED-I (55.7%, controls). On univariate analysis, factors associated with increased risk of device infection included fever (Odds ratio [OR] 5.65, 95% confidence interval [CI] [1.45-22.04], p-value 0.011), persistent bacteremia at 72h (OR 2.89, CI [0.97- 8.60], p-value 0.052), and tachycardia (OR 2.41, CI [0.82- 7.10], p-value 0.098). Factors associated with decreased risk of device infection included end stage renal disease (ESRD) (OR 0.24, CI [0.07 - 0.81], p-value 0.029) and immunosuppression in the past 3 months (OR 0.23, CI [0.05- 1.16], p-value 0.096). On multivariate analysis only fever remained significantly associated with device infection (OR 6.58, CI [1.20-36.04]). Mortality at 30 and 365 days was not significantly different between cases and controls.
Fever, tachycardia and persistent bacteremia were associated with increased risk of CIED-I among patient with SAB, while ESRD and immunosuppression were protective on univariate analysis. Only fever remained significantly associated with CIED-I on multivariate analysis.
M. Brimacombe, None
K. Hammoud, None
R. Dendi, None
W. El Atrouni, None