Background and purpose: In this study, we investigated the stroke severity was associated with the prior antithrombotic medication including novel Vitamin K antagonist oral anticoagulants (NOACs) in patients with nonvalvular atrial fibrillation (NVAF).
Methods: We included 801 consecutive acute ischemic stroke or transient ischemic attack patients with NVAF who were admitted to 6 hospitals between August 2013 and January 2017 in the present study. Stroke severity was assessed using the National Institute of Health Stroke Scale (NIHSS). Prior antithrombotics before index stroke were categorized into 5 groups: no antithrombotics, only antiplatelet, warfarin with international normalized ratio (INR) <2, warfarin with INR ≥2, and NOACs. We investigated whether there were differences in initial stroke severity according to the prior antithrombotics in stroke patients with NVAF.
Results: A total of 801 acute ischemic stroke or transient ischemic stroke patients with NVAF were enrolled. Among the 801 patients, the 34 (4.2%) had been treated with warfarin with INR ≥2, 146 (18.2%) with warfarin with INR ≥2, 70 (8.7%) with NOACs, 347 (43.3%) with only antiplatelet, and 204 (25.5%) without any antithrombotics. The median NIHSS score was 5 (IQR 1-14). Compared with the no antithrombotics group (9.5, IQR 2-16), the NIHSS was lower in the warfarin with INR ≥2 (4, 1-7.3) and the only antiplatelet group (4, IQR 1-12), while the warfarin with INR <2 (6, IQR 2-14) or the NOACs group (4, IQR 1-15) had similar stroke severity. Multivariate analysis adjusting the CHA2DS2-VASc score showed stroke severity was milder in patients with warfarin with INR ≥2 (b -4.680, SE 1.399, p=0.001), those with antiplatelet only (b -2.528, SE 0.667, p<0.001), or those with NOACs (b -2.290, SE 1.049, p=0.029), compared with those without any antithrombotics.
Conclusions: Our data indicate that the prior anticoagulation was related with milder initial stroke severity in patients with NVAF.