ABO Blood Type and Response of Activated Partial Thromboplastin Time to Dabigatran in Nonvalvular Atrial Fibrillation Patients.

Background: The association between ABO blood type and the activated partial thromboplastin time (aPTT) under dabigatran therapy in nonvalvular atrial fibrillation (NVAF) patients is unclear.

Methods and results: Between 2011 March and 2015 May, data on ABO blood type and aPTT under dabigatran were obtained for 396 NVAF patients (baseline aPTT, 166). The prevalence of blood type O tended to increase or significantly increase according to baseline aPTT, aPTT under dabigatran, and their difference (∆aPTT) (P=0.054, 0.001, and 0.012, respectively).

Conclusions: In these NVAF patients, a high aPTT value under dabigatran therapy was associated with blood type O.