Evaluation of the activated partial thromboplastin time and its influential factors in ischemic heart disease patients under heparin treatment

This study aimed to detect the defects of the current methods used to monitor unfractionated heparin (UFH) anticoagulant effect and find possible assistive parameters for activated partial thromboplastin time (aPTT) test to improve treatment performance. The required information was gathered from patients' case records, treatment charts and laboratory reports. Kendall's tau correlation coefficient was calculated for analysing the relationship between variables. The partial least squares (PLS) and the stepwise multiple regression were operated, and the area under the receiver operating characteristic curve (AUC) and the r-squared (r2) were used to show the analytical ability of the models, respectively. Overall, 102 UFH-receiving ischemic heart disease patients participated in this study. The aPTT value varied from 30 to 95 s (mean ± SD = 44 ± 14). Therapeutic aPTT values were observed in 15% of hospitalization days. The aPTT value showed statistically significant correlations with mean UFH infusion (U/kg/h), age, prothrombin time (PT), smoking, international normalized ratio, haemoglobin (Hgb) and blood triglyceride level. Triglyceride level and PT were efficacious predictors of aPTT value (P < 0.001, r2 = 0.336). Moreover, blood urea nitrogen (BUN) and blood creatinine (Cr) levels were the best predictors for mortality. The mean BUN/Cr ratio was 18 ± 5 and 25 ± 12 in nonexpired and expired subjects, respectively. If calibrated institution-specific therapeutic aPTT ranges and updated weight-based UFH nomograms get employed, aPTT test, along with the BUN/Cr ratio and Hgb level, as assistive parameters for predicting haemorrhagic incidents, would be near ideal monitoring method in UFH-receiving patients.