Early predictive value of procalcitonin for the diagnosis of pulmonary infections after off-pump coronary artery bypass grafting

Abstract

Background: Cardiac surgery can cause similar inflammatory reactions with infection; antibacterial treatment may be inappropriately used. Early and accurate diagnosis of infection still is a difficult problem worldwide. Procalcitonin (PCT) helps to identify sepsis caused by bacterial infections. However, its application in the diagnosis of pulmonary infections after off-pump coronary artery bypass grafting (OPCABG) has not been well studied. We investigated the early predictive value of PCT for the diagnosis of pulmonary infections after OPCABG. Methods: We retrospectively analyzed the clinical data, including conditions in the intensive care unit, postoperative complications, mortality rate, plasma PCT in the morning on the first postoperative day, routine white blood cell (WBC) count, and high-sensitivity C-reactive protein (hs-CRP) levels of patients who underwent elective OPCABG. Patients were divided into an infection group and a noninfection group, according to the occurrence of pulmonary infections. A receiver operating characteristic (ROC) curve was used to analyze the predictive value of PCT for the diagnosis of postsurgical infections. Results: In total, 131 patients who underwent OPCABG were included, of whom 23 (17.6%) developed pulmonary infections. The plasma PCT level significantly was higher in the infection group than in the noninfection group (6.0 ± 6.3 ng/ml vs. 2.0 ± 2.2 ng/ml, P = 0.007). WBC and hs-CRP values were not significantly different between the infection group and the noninfection group (12.3 ± 3.9×109/L vs. 11.1 ± 2.8×109/L, P = 0.171 and 12.4 ± 0.7 mg/L vs. 12.4 ± 0.8 mg/L, P = 0.903, respectively). The area under the ROC for predicting pulmonary infections after OPCABG by plasma PCT was 0.783 (P < 0.001, with a 95% confidence interval of 0.674-0.893), with a cut-off value of 3.55 ng/ml, a sensitivity of 0.609, and a specificity of 0.861. Conclusion: From our study results, we postulate that PCT has a high early predictive value for the diagnosis of pulmonary infections after OPCABG.