Objective: The purpose of the present study is to assess if perioperative variation of Brain Natriuretic Peptide (BNP) levels is a predictor of mortality and morbidity after cardiac surgery.Material and Methods: 500 consecutive patients will be enrolled prospectively in this study before cardiac surgery under cardiopulmonary bypass. BNP levels will be measured prior to surgery and at postoperative day 1. Variations of BNP levels will be analyzed to determine if it is a predictor of mortality and morbidity after cardiac surgery. This dynamic evaluation will be compared to other tools of risk stratification in cardiac surgery as the EuroScore. All patients will be followed 3 years after the procedure.

Hypothesis: Perioperative BNP variations may be more sensitive than pre- or postoperative BNP levels alone. Furthermore the perioperative homeostasis will be measured to assess its impact on BNP secretion during the perioperative period.