Luck in Unluckiness: Influence of Anticoagulant Therapy on Severity of Stroke in Atrial Fibrillation
A recent Swiss study evaluated the severity, complications, and outcomes of cerebrovascular accidents (CVAs) in patients with atrial fibrillation considering prior anticoagulant therapy use and its type. This allowed for a comparison between direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs).
Analyzed Data
The study published last year in the prestigious journal Annals of Neurology drew from the Swiss stroke patient registry. The authors evaluated data from 2014-2019. They compared the severity of strokes at hospital admission assessed by the NIHSS (National Institutes of Health Stroke Scale), the use of intravenous thrombolysis (IVT) or mechanical thrombectomy, the occurrence of symptomatic intracranial bleeding, and functional outcomes at 3 months assessed by the modified Rankin Scale (mRS) in patients with atrial fibrillation who used DOACs, VKAs, or no anticoagulant therapy at all before the stroke.
Key Findings
The average age of patients was 79.8 years, with a male to female ratio of 51:49. Out of the total 8179 patients, 1489 (18%) were on VKAs before the stroke, 1634 (20%) used DOACs (dabigatran, rivaroxaban, apixaban, edoxaban), and 5059 (62%) formed the control group with no anticoagulant use prior to the stroke.
The severity of strokes was lowest in the group of patients who used DOACs before the stroke (median NIHSS = 4 vs. median NIHSS for the VKAs group = 6 vs. median NIHSS for the control group = 7).
IVT was administered most frequently in the control group (74% vs. VKA group 63% vs. DOAC group 15%). Intracranial bleeding occurred after IVT in 3.6% of patients in the control group, 4.6% in those previously treated with VKAs, and 3.1% in those previously treated with DOACs.
Regarding outcomes at 3 months, the group that used DOACs before the stroke had the highest proportion of patients (60%) with favorable results on the Rankin Scale (0-2) compared to 55% of patients in the group treated with VKAs before the stroke.
Conclusion
Use of DOACs in patients with atrial fibrillation was associated with less severe ischemic strokes at hospital admission and less frequent IVT administration compared to patients with prior VKA treatment or no anticoagulant treatment. Three months after the stroke, patients treated with DOACs before the event had fewer functional consequences compared to those previously treated with VKAs.
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Source: Meinel T. R., Branca M., De Marchis G. M. et al. Prior anticoagulation in patients with ischemic stroke and atrial fibrillation. Ann Neurol 2021; 89 (1): 42–53, doi: 10.1002/ana.25917.
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