Intraoperative: The type of surgery will be classified. The following data will be recorded: heparin dose given prior to bypass initiation; activated clotting time (ACT) counts during the operation (prior, during and after CPB); operative time, cross-clamp time and CPB time; number of trials to wean from CPB, type of inotropes and dosage used during weaning from CPB; blood products utilization during surgery. Allergic reactions or adverse events observed by the surgeon or anesthesiologist will be documented. The individual surgeon's impression regarding bleeding tendency will be recorded.