The Influence Of Dabigatran On Coagulation Assays:How And Why

Objective: By testing the Activated partial thromboplastin time(APTT), Prothrombin time(PT), Thrombin time(TT) and the activity of Ⅱ factor(FⅡ) and dabigatran concentration of atrial fibrillation patients who take dabigatran etexilate 110 mg twice a day, how and why it effect on the coagulation assays were analyzed.Methods:28 non-valvular atrial fibrillation patients who take dabigatran etexilate 110 mg twice a day were enrolled in our study. The clinical dates(such as body mass index, blood chemistry) of the patients were collected. The indexes such as Activated partial thromboplastin time(APTT), Prothrombin time(PT), Thrombin time(TT), dabigatran concentration and the activity of Ⅱ factor(FⅡ) were tested.And 5 patients(3 men) whose creatinine clearance were greater than 80ml/min(normal renal function) were selected. The dabigatran concentration were tested before and 0.5 hours,2 hours, 5 hours, 12 hours after their first dose. According to the creatinine clearance all patients were divided into A group of 15 patients(creatinine clearance >50ml/min, mild renal impairment or normal) and B subgroup of 13 patients(30ml/min< creatinine clearance ≤50ml/min, patients with moderate renal impairment); According to APTT all patients were divided into APTT normal group and APTT elevated group. And divided into normal PT and PT increased group according< to PT.Results: The pharmacokinetic analysis found that at about two hours the concentration reached a peak(102.4+10.6ng/ml).TT prolonged obviously in all patients before and after taking dabigatran, the difference was of statistically significant(16.2±2.1 VS 98.6±32.4, P <0.01).And the APTT increased significantly(30.8±4.3 VS 40.2±3.4, P <0.05). However the PT and FⅡ activity were of no significant change. The dabigatran concentration and TT, APTT were of significant linear correlation(TT: R=0.84, P <0.01; APTT: R=0.34, P<0.05). But PT was of no significant correlation. Dabigatran concentration and the creatinine clearance rate was of negative correlation(R =-0.68, P <0.05). PT has no significant change in A group,but were of significantly different in B group(PT:12.2±1.6 VS 14.6±2.2, P <0.05). The dabigatran concentration of B subgroup were significantly higher than A subgroup(143.2±42.4ng /ml VS 96.4±25.4ng/ml, P<0.05).Conclusion: 1. After a single dose of dabigatran etexilate 110 mg the plasma concentration reached a peak at about two hours; 2. TT, APTT prolonged after taking dabigatran etexilate 110 mg twice a day and TT extended more obvious; 3. Patients with mild renal impairment or normal taking dabigatran 110 mg twice a day PT had no significant change, but in patients with moderate kidney function injury the PT were prolonged of different degrees; 4. Creatinine clearance can affect the concentration of dabigatran etexilate,in patients whose creatinine clearancerate is lower the drug concentration was higher.