[Kinetics, diagnostic and prognostic value of procalcitonin after cardiac surgery]

Cardiac surgery with cardiopulmonary bypass (CPB) can cause a systemic inflammatory response (SIRS) making difficult the interpretation of inflammatory markers. Procalcitonin (PCT) is a marker of inflammation that appears to be a good early marker of infection after cardiac surgery. To study the kinetics of PCT after cardiac surgery with CPB and to determine its diagnostic and prognostic value. This is a prospective observational study including 40 adult patients consecutively operated for a coronary or valve surgery with CPB, so programmed or semi-urgent. The anesthetic protocol was standardized for all patients. A determination of PCT and CRP was performed before the CEC, at the decision of the CEC (H0), 4 hours after (H4), then H24, H48, H72 and H96. The rate of PCT and CRP increased significantly from the H4 until 4(th) day compared to baseline. (p<0.05). The concentration of PCT increased at the end of CPB, reaching its peak on 1(st) day (0.96±1.00 ng/mL) and then declined rapidly to J2, J3 and J4. CRP showed a slower kinetics with a peak on day 2 (204±81 mg/L) and decreased more slowly. PCT levels showed no significant variation depending on the type of surgery and they were significantly increased in cases of severe SIRS, late postoperative infection and postoperative renal dysfunction (PORD). However, the rates of CRP were not correlated with these complications. According to ROC curve analysis, a threshold value of 0.958 ng/mL PCT measured on the 1(st) day after surgery had a sensitivity of 85% and a specificity of 95% for the prediction of severe SIRS with organ dysfunction. For a threshold of 1.2 ng/mL measured at day 1 postoperatively, the PCT has a sensitivity of 100% and a specificity of 96% for predicting late infection. For a threshold value of 0.475 ng/mL measured at the decision of the CPB, the PCT has a sensitivity of 80% and a specificity of 69% for predicting PORD. PCT levels were correlated with severity scores. They were also correlated with length of stayin ICU. According to ROC curve analysis, a cutoff of 0.737 ng/mL measured at 1(st )postoperative day, the PCT has a sensitivity of 76% and a specificity of 91% for the prediction of an ICU stay of more 3 days with AUC=0.818. The PCT is a marker that has a fast kinetics and can early predict severe SIRS, and late postoperative infection as well as PORD.