Enhanced preoperative C-reactive protein plasma levels predict postoperative infections in patients undergoing cardiac surgery

Introduction

Some patients undergoing cardiac surgery show enhanced levels of C-reactive protein (CRP) before surgery. Recently, postoperatively enhanced CRP levels have been related to postoperative infections. The question therefore arises whether preoperatively enhanced CRP levels are a risk factor for postoperative infections in patients undergoing cardiac surgery.

Measurements and results

CRP was measured in 863 patients undergoing cardiac surgery with cardiopulmonary bypass. CPR levels were determined on daily intervals from the day before surgery till day 6 after surgery. Furthermore, we documented infectious diseases related data. Patients developing an infection during the postoperative course had significantly higher CRP levels at the day before surgery, 17.7 ± 4 mg/l vs. 7.8 ± 0.7 mg/l. Furthermore, CRP levels in patients developing an infection were significantly higher at day 1, 4 and still at day 6 after surgery. The incidence of postoperative infections was significantly higher in patients with enhanced preoperative CRP levels than in those with normal preoperative CRP levels (upper quartile vs. lower three quartiles), 25.0% vs. 11.2% respectively. Furthermore, the length of postoperative hospital stay was significantly longer in patients with enhanced preoperative CRP levels than in those with normal preoperative CRP levels, 9.6 ± 0.8 vs 7.6 ± 0.3 days. Multivariate analysis including the variables enhanced preoperative CRP, and CPB duration, age, gender, and diabetes mellitus demonstrated that preoperatively enhanced CRP wast the most important independent variable predicting postoperative infection (OR, 2.7; 95% CI, 1.6 to 4.3).

Conclusion

This study shows for the first time that preoperative measurement of CRP may offer a useful, predictive marker in risk stratification for postoperative infections in patients scheduled for cardiac surgery.