Thorac Cardiovasc Surg 2016; 64 - OP97
DOI: 10.1055/s-0036-1571550

Adding Vancomycin to Perioperative Prophylaxis Decreases Deep Sternal Wound Infections in High-risk Cardiac Surgery Patients

S. Reineke 1, B. Gahl 1, U. Führer 2, C. Seidl 3, M. Bächli 2, L. Englberger 1, J. Marschall 2, T. Carrel 1
  • 1Bern University Hospital, Cardiovascular Surgery, Bern, Switzerland
  • 2Bern University Hospital, Infectious Diseases and Hospital Epidemiology, Bern, Switzerland
  • 3Bern University Hospital, Anesthesiology, Bern, Switzerland

Objectives: Cephalosporin perioperative prophylaxis reduces sternal wound infections (SWI) after cardiac surgery. However, ≥50% of coagulase negative staphylococci, a major pathogen, is resistant to cephalosporins in our region. The aim of this study was to determine the impact of adjunctive vancomycin on SWIs in a high-risk patient population.

Methods: We conducted a pre-/post-intervention study in an academic hospital in Bern, Switzerland, from 1/2010 - 12/2013. Pre-intervention, patients received perioperative prophylaxis with 1.5 g cefuroxime (TID x 24–48h). In the intervention period, starting 1/2012, high-risk patients received cefuroxime plus vancomycin (1 g). High-risk was defined as meeting any criterion: BMI ≤18 or ≥30m2/kg, re-operation, renal failure, diabetes mellitus, chronic obstructive pulmonary disease, or immunosuppressive medication. We recorded the SWI rate according to CDC NHSN criteria. We used time series analysis to study trends in SWI rate in low-risk patients, controlling for autocorrelation. After trend exclusion, we used logistic regression to determine the effect of vancomycin adjusting for high-risk status.

Results: 3902 patients were included (1915 pre- and 1987 post-intervention), among whom 1493 (38%) were high-risk patients. In the high-risk group, we found 70 SWIs/711 patients (9.8%) before and 21/782 patients (2.7%) after the intervention. Focusing on the 46 deep SWIs (DSWI), we saw 38/711 (5.3%) DSWIs before and 8/782 (1.0%) after the intervention; the absolute risk difference of 4.3% yields a number needed to treat (NNT) of 24 to prevent 1 DSWI. When correcting for high-risk status, the intervention significantly reduced the overall SWI rate (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.26–0.67, p< 0.001] and the subset of DSWIs (OR 0.30, 95%CI 0.14–0.62, p = 0.001). In contrast, the infection rate in low-risk remained largely unchanged over the study period (cf. Fig. 1).

Conclusions: Adding vancomycin to standard antibiotic prophylaxis in high-risk cardiac surgery patients significantly reduced both overall and deep SWIs. Given the NNT of 24 this intervention appears to be a highly effective preventive strategy.

Fig. 1.