“…However, excessive usage of heparin can result in bleeding event, and its antithrombotic effect varies among patients, necessitating close monitoring in standard practice [ 5 , 6 ]. Heparin effect can be directly observed by using anti-activated factor X (anti-Xa) activity or activated partial thromboplastin time (aPTT) ratio which is more widely used and economically reasonable in our setting [ 7 , 8 ].…”