Prothrombin time on admission in patients with cardioembolic stroke and intracranial hemorrhage occurring during warfarin treatment in the direct oral anticoagulant era.

Warfarin is used worldwide to prevent cardioembolic stroke (CES) in patients with atrial fibrillation even in the era of direct oral anticoagulant (DOAC). We evaluated clinical characteristics of the patients with CES and intracerebral hemorrhage (ICH) occurring during warfarin treatment, focusing on prothrombin time-international normalized ratio (PT-INR) at the occurrence. The consecutive 846 CES patients (78 ± 9 years) and 870 ICH patients (68 ± 13 years) admitted to the Hirosaki Stroke and Rehabilitation Center from April 2011 through March 2015 were studied. The antithrombotic agents administered in CES patients before the onset included antiplatelets in 146 patients (17%), warfarin in 205 (24%), DOAC in 37 (5%), and none in the other 458 (54%). Mean PT-INR within 24 hours after the onset in nonvalvular atrial fibrillation patients with warfarin was 1.34 ± 0.33 (n = 129), and 111 of them (86%) showed PT-INR value below the recommended therapeutic range in Japan. The antithrombotic agents administered in ICH patient included antiplatelets in 87 patients (10%), warfarin in 86 (10%), DOAC in 8 (1%), and none in the other 689 (79%). Mean PT-INR within 24 hours after the onset in patients with warfarin was 2.27 ± 0.62 (n = 65), and 56 of them (86%) showed PT-INR < 2.8. Thus, there is a large population with poor warfarin control complicating CES and that with good warfarin control complicating ICH, indicating limitation of warfarin treatment in the DOAC era.