Ying Gue, PhD
Jung YH, Kim YD, Kim J, Han SW, Oh MS, Lee JS, Lee K-Y. Initial Stroke Severity in Patients With Atrial Fibrillation According to Antithrombotic Therapy Before Ischemic Stroke. Stroke. 2020;51:2733–2741.
The use of oral anticoagulants (OAC) has been shown to reduce the incidence of stroke in patients with atrial fibrillation (AF). Apart from a study in 2006,1 there has not been any contemporary data exploring the association of OAC and stroke severity.
This study explores 10 years’ worth of data from a multicenter stroke registry in Korea investigating severity of acute ischemic stroke (AIS) and its relation to antithrombotic use (divided into none vs. antiplatelets vs. OAC) in patients with a history of AF. Out of a total of 77579 patients in the database, 6786 had a diagnosis of AF prior to their presentation with AIS. 2304 were not on antithrombotics, 2701 were on antiplatelets, and 1781 were on OAC.
The authors shared two main learning points. Firstly, in the patient group which the authors classified as meeting criteria for oral anticoagulation (CHA2DS2-VASc score≥2 and ATRIA bleeding risk score≤4), there was a significant increase in use of OAC and decrease in antiplatelet use. The reduction in antiplatelet use coincides with the 2016 guideline recommendation that antiplatelet monotherapy should not be used for stroke prevention in AF.
Secondly, patients that were not on antithrombotics had a significantly higher NIHSS score on admission when compared to the antiplatelet and OAC group (8 [3 – 15] vs. 7 [2 – 15] vs. 6 [2 – 14], p<0.001) with no difference between the antiplatelet and OAC groups (p=0.776). There was no difference in mortality (p=0.062). Multivariate analysis, adjusting for significant variables, showed that antithrombotics in patients with AF prior to AIS was associated with a significant higher likelihood of a mild initial neurological deficit and favourable outcome at discharge. This was similar to the findings of the 2006 study1.
This study highlights that apart from preventing AIS, the use of OAC is associated with a reduction of severity of AIS in patients with AF. However, as the authors rightly pointed out, being an observational study, many undocumented confounding could affect validity of findings.
This study has shown that apart from occurrence of stroke, research exploring the risks and benefits in terms of stroke severity and neurological outcomes could represent a different outcome for future studies, especially in patients who were conventionally not anticoagulated (low CHA2DS2-VASc score with high ATRIA bleeding score) to assess for net clinical benefit of antithrombotic therapies in this cohort.
- O’Donnell M, Oczkowski W, Fang J, Kearon C, Silva J, Bradley C, Guyatt G, Gould L, D’Uva C, Kapral M, et al. Preadmission antithrombotic treatment and stroke severity in patients with atrial fibrillation and acute ischaemic stroke: an observational study. Lancet Neurol. 2006;5:749–754.