Unfractionated Heparin 투여 환자의 Activated Partial Thromboplastin Time (aPTT)에 영향을 미치는 요인 평가

Abstract

Unfractionated heparin (UFH) is an anticoagulant, widely used for more than 50 years. In order to induce a target effect, a weight-adjusted dosing regimen is used due to the large deviation of responses among the patients. Even with an accurate heparin dose based on one’s weight, but depending on the patient, many cases cannot maintain aPTT within the target range. Therefore, this study aimed to analyze correlations between the aPTT measured 12 hours after the administration, and clinicopathologic factors of the patients, in order to understand which factors affect the results of aPTT. First, medical records of 87 cardiovascular patients, who were hospitalized in a cardiac intensive care unit from September 2012 to August 2013 receiving UFH at the rate of 12 IU/kg/hr (±10%), were reviewed and analyzed. They were checked to see whether there were differences of aPTT results 12 hours after the administration based on the various clinicopathologic factors of the patient, such as gender, age, weight, diabetes mellitus, and smoking history. A correlation between aPTT results and any bleeding (a heparin-related adverse reaction) was also studied. The mean aPTT measured 12 hours after the start of administration was 50.22 sec (± 21.32). The mean aPTT was lower in male patients (p= 0.0048) less than 65 years old (p= 0.0002) weighed 70 kg or more (p= 0.0063) and had a creatinine clearance (CrCl) of 50 ml/min or more (p= 0.0001), when compared to other groups. They also had a higher ratio of the patients who did not meet the target aPTT. Patients with a malignant tumor (p= 0.0050) or pulmonary embolism (p= 0.0206) had a higher mean aPTT, and a higher patient ratio exceeding the target aPTT. Among them, a malignant tumor's significant effect was confirmed with a multiple regression analysis. Malignant tumor patients showed an increase of aPTT by about 25% (p= 0.0122). Heparin-related bleeding occurred in 23 patients (26.44%), and although incidence of bleeding was higher in the patients who exceeded the target range of aPTT, its significance was a marginal value (p= 0.0575). It can be concluded that a malignant tumor is a potential factor to increase aPTT levels, but gender, age, body weight, renal function, or pulmonary embolism may be the affecting factors. If we can reveal the accurate affecting factors through additional studies with a large number of patients, we can safely and effectively pursue the heparin dose-adjustment method.