Concentrations of dabigatran administered after acute ischemic stroke.

The aim of this study was to evaluate the anticoagulation intensity of dabigatran for acute ischemic stroke patients and hemorrhagic/ischemic events after early initiation of dabigatran.

Acute ischemic stroke/transient ischemic attack (TIA) patients admitted to our hospital who started dabigatran from January 2012 to December 2017 were studied. Blood samples were drawn just before (0 h) and 4 h after dabigatran at a median of 5 days after starting dabigatran to measure dabigatran concentrations (C_0h, C_4h) based on the thrombin clotting time assay (Hemoclot®).

Of the 70 patients (54 men, 69 ± 9 y), 14 started dabigatran after a TIA, and 56 started it after an ischemic stroke a median of 5 days after onset. C_0h, C_4h was 82.5 ± 58.0, 143.1 ± 98.2 ng/dl (150 mg BID, 35 patients) and 50.6 ± 40.9, 91.2 ± 64.7 ng/ml (110 mg BID, 35 patients). During a median follow-up of 382 (IQR 109-688) days of all 70 patients, five had clinical events. Three patients had bleeding events, two with nasal bleeding (C_0h, C_4h: 50, 80 ng/ml, C_0h, C_4h: 91, 173 ng/ml) and one with GI bleeding (C_0h, C_4h: 5, 5 ng/ml). Two patients had ischemic events, one with ischemic stroke (C_0h, C_4h: 10, 50 ng/ml) and another with acute myocardial infarction (C_0h, C_4h: 40, 40 ng/ml).

There was no obvious relationship between dabigatran concentration and hemorrhagic/ischemic events in this study. Larger sample study will be needed to examine the relationship between the concentration and events in clinical practice.