Khalid, Sana

Objectives: Clinicians need to identify which patients presenting with S. aureus bacteremia (SAB) have underlying cardiovascular implantable electronic device (CIED) infection and therefore need device extraction. The goal of this study was to identify clinical predictors of CIED infection in patients presenting with SAB. Methods: We retrospectively reviewed all cases of SAB in CIED recipients at Mayo Clinic from Jan 2001 to Dec 2011. CIED infection was defined using clinical, microbiologic and echocardiographic criteria. Patients who presented with clinical signs of CIED pocket infection were excluded. A multivariable model was developed to identify independent predictors of CIED infection. Model discrimination was summarized using the area under a receiver operating characteristics curve (AUC). Results: Among the 131 patients with SAB and CIED, 45 (34%) had underlying CIED infection. Permanent pacemaker (PPM) devices (OR 3.90, 95% CI 1.65-9.23, p=0.002), >1 device-related procedure (OR 3.30, 95% CI 1.23-8.86, p=0.018), and duration of SAB ≥4 days (OR 5.54, 95% CI 3.32-13.23, p <0.001) were independently associated with an increased risk of CIED infection. The AUC for this multivariable model was 0.79 indicating good discriminatory capacity to separate SAB patients with and without CIED infection. Various combinations of these three features and the corresponding predicted probabilities of CIED infection are summarized in Table. Conclusions: An individual patient’s risk of underlying CIED infection can be calculated based on the type of device, number of device-related procedures, and duration of SAB. Patients without any of these high-risk features have very low risk of underlying CIED infection and may be monitored closely without immediate device extraction.

Background— Prompt recognition of underlying cardiovascular implantable electronic device (CIED) infection in patients presenting with Staphylococcus aureus bacteremia (SAB) is critical for optimal management of these cases. The goal of this study was to identify clinical predictors of CIED infection in patients presenting with SAB and no signs of pocket infection. Methods and Results— All cases of SAB in CIED recipients at Mayo Clinic from 2001 to 2011 were retrospectively reviewed. We identified 131 patients with CIED who presented with SAB and had no clinical signs of device pocket infection. Forty-five (34%) of these patients had underlying CIED infection based on clinical or echocardiographic criteria. The presence of a permanent pacemaker rather than an implantable cardioverter-defibrillator (odds ratio, 3.90; 95% confidence interval, 1.65–9.23; P =0.002), >1 device-related procedure (odds ratio, 3.30; 95% confidence interval, 1.23–8.86; P =0.018), and duration of SAB ≥4 days (odds ratio, 5.54; 95% confidence interval, 3.32–13.23; P <0.001) were independently associated with an increased risk of CIED infection in a multivariable model. The area under the receiver operating characteristics curve for the multivariable model was 0.79, indicating a good discriminatory capacity to distinguish SAB patients with and without CIED infection. Conclusions— Among patients presenting with SAB and no signs of pocket infection, the risk of underlying CIED infection can be calculated based on the type of device, number of device-related procedures, and duration of SAB. We propose that patients without any of these high-risk features have a low risk of underlying CIED infection and may be monitored closely without immediate device extraction. Prospective studies are needed to validate this risk prediction model.