Brain natriuretic peptide a predictive marker in cardiac surgery

BNP which stands for B-type natriuretic peptide is a cardiac neurohormone and is secreted in response to myocardial stress and causes natriuresis and vasodilatation. Studies have reported close correlation between a high concentration of BNP in blood and worse short-term and long-term prognosis following myocardial infarction and heart failure. In this study, we have tested its usefulness and predictive value in the outcome post cardiac surgery.

Between March 2006 and June 2007, 141 patients, undergoing cardiac surgery, were enrolled in this study. Their BNP concentration was measured prior to the operation and their comorbidities were examined against their BNP levels. Postoperatively their outcome was closely monitored. Main clinical endpoints were atrial fibrillation (AF), inotrope use, renal impairment, early deaths and hospital stay.

Some preoperative comorbidities, such as renal impairment, peripheral vascular disease (PVD) and low ejection fraction (EF) were associated with higher BNP level. Statistically, EuroSCORE and Parsonnet score showed significant correlation with preoperative BNP concentration (P<0.0001). Postoperatively, high-BNP concentration predicted inotropic use, higher than baseline creatinine level, longer ventilation time, longer hospital stay and early mortality (P<0.05) but our study did not reveal any predictive value for BNP in identifying those developing AF or infection postoperatively.

BNP is a valuable biochemical marker, which is easy to measure and can be beneficial in predicting the operative outcome.