Background & Aim: clamp and also blood stasis during vascular surgeries. Heparin is administered to prevent thrombosis, and aPTT (activatedPartial Thromboplastin Time) test is used to make sure of anticoagulative effect of heparin. At the end of the operation,heparin is neutralized by protamin sulfate in some centers. In this study we assessed the necessity of aPTT and usingprotamin during vasc...