Perioperative dynamics of activated partial thromboplastin time and prothrombin time-international normalized ratio. These results give an overall impression of postoperative normo- or hypocoagulability. Shaded areas indicate the manufacturers’ reference ranges. aPTT: activated partial thromboplastin time. PT-INR: prothrombin time-international normalized ratio. Preop: preoperative test results. Postop: test results taken on the day on which epidural catheters were removed. s: seconds. *: significant difference between pre- and postoperative results (p<0.05, Student’s paired t-test).