The Role of Procalcitonin and N-Terminal Pro-B-Type Natriuretic Peptide in Predicting Outcome after Cardiac Surgery

Objective(s): Determine the thresholds of procalcitonin (PCT) and N-terminal pro-B-type natriuretic peptide (Nt-pro-BNP) associated with poor prognosis after heart surgery with CPB.

Design: Prospective observational study.

Setting: Academic Medical Center Habib Bourguiba.

Participants: Adult patients consecutively operated for coronary or valve surgery with CPB, elective or semi-urgent. Interventions: Serum concentrations of PCT and Nt-pro-BNP were determined before and after CPB, in the fourth postoperative hour (H4) and every day during the first 4 days. Receiver-operating characteristic curves and cut-off values were used to assess the ability of these markers to predict length of intensive care unit (ICU) stay >3 days. Measurements and Main

Results: Forty patients were included in the study. Systemic inflammatory response syndrome (SIRS) occurred in 35 (87.5%) patients. Seventeen of them (42.5%) showed severe SIRS. Significantly higher serum concentrations of Nt-pro-BNP and PCT were found in patients with severe SIRS. Receiver operating characteristic (ROC) analysis showed that the threshold of PCT was 0.737 ng/mL and that of Nt-pro-BNP was 1235 pg/mL on day 1 could predict an ICU stay of more than 3 days. The association of Nt-pro-BNP to procalcitonin (p=0.009) better predicted the ICU stay than PCT alone (p=0.02) or Nt-pro-BNP alone (p=0.03). The best combination is Nt-pro-BNP + PCT + C-reactive protein (CRP) (p=0.007). CONCLUSIONS: PCT and Nt-pro-BNP on day 1 may be associated with severe SIRS and predict the length of stay. A biomarker approach combining PCT, CRP and BNP is superior to a traditional single marker for predicting ICU stay.