Cardiopulmonary by-pass (CBP) during cardiac surgery leads to deleterious systemic inflammatory response. In a prospective cohort of 46 patients older than 18 years and eligible for non-urgent cardiac surgery with CPB, measurement of sTREM-1 in the plasma was performed immediately after the onset of anesthesia (H0) and 2 and 24 hours after CBP. After CBP, sTREM-1 significantly increased at H2 and at H24 (p<0.001). Based on both baseline sTREM-1 levels and variations, 3 patterns of patients were identified. Profile 1 group with high baseline sTREM-1 levels as well as high increase, developed more severe organ failure after CBP with higher norepinephrine dose at H24, higher SOFA score and more frequently AKI at both H24 and H48. Finally, acute atrial fibrillation at H24 was more frequent in profile 1 when compared to profile 2/3. Profile 1 group had longer ICU and hospital length of stay (LOS). In conclusion, early sTREM-1 variations after cardiac surgery identified a group of patients at high risk for post-operative AKI and prolonged length of stay. Thus sTREM-1 represents a relevant biomarker and biotarget in cardiac surgery with CBP.