Arterial blood samples were drawn for analysis after induction of anesthesia (T0),10 minutes after the administration of heparin (T1), at unclamping of the aorta (T2) and after heparin reversal with protamine (T3). The following tests will be performed: EXTEM, INTEM, HEPTEM and a heparinase modified EXTEM. For the latter, recombinant thromboplatin instead of the elagic acid is used in the HEPTEM test. Heparin concentrations are measured at T1 and at the end of bypass (T2). HEPCON® was used for heparin management.