Early anticoagulation after ischaemic stroke “reasonable” and “unlikely to cause harm”

Urs Fischer presenting at ESOC 2023

An international clinical trial presented today at the European Stroke Organisation Conference (ESOC; 24–26 May, Munich, Germany) has demonstrated that—in people with ischaemic stroke and atrial fibrillation—anticoagulation can safely be started earlier than current guidelines recommend.

“Our study finally brings scientific evidence for a common dilemma in early secondary prevention after an ischaemic stroke,” said study leader Urs Fischer (University Hospital of Bern, Bern, Switzerland), who delivered these findings from the ELAN trial. “In view of our results, early treatment initiation is reasonable if indicated, or if desired, for logistic or other reasons. It is probably better and is unlikely to cause harm.”

Direct oral anticoagulants (DOACs) are used to prevent blood clots in people with atrial fibrillation, but it is unclear how early after stroke they should be started; there are safety concerns surrounding a potential increased risk of bleeding, which may be highest in the first few days post-stroke, but the possible benefit of such drugs may also be highest in these first few days. In the presence of this uncertainty, international guidelines currently recommend a delay before starting DOACs.

However, as per Fischer’s presentation earlier today, the chances of suffering a recurrent event with early DOAC treatment are likely to be lower compared to a later start—without an increase in risk of complications.

The ELAN study included 2,013 participants with an acute ischaemic stroke and atrial fibrillation recruited from 103 different stroke units in 15 countries across Europe, the Middle East and Asia between 2017 and 2022.

Based on the size and location of their infarct on imaging—and, thus, the severity of their stroke—participants were randomly assigned to an early treatment start, or a later, guideline-recommended treatment start. An early start was defined as being within 48 hours of a minor/moderate stroke or day 6–7 following a major stroke, while a late start was defined as day 3–4 following a minor stroke, day 6–7 following a moderate stroke, or day 12–14 following a major stroke.

The primary outcome in the ELAN trial was a composite of recurrent ischaemic stroke, symptomatic intracranial haemorrhage (ICH), extracranial bleeding, systemic embolism, or vascular death, within 30 days after randomisation.

Primary outcome results in ELAN

At 30 days, the primary outcome occurred in 29 patients (2.9%) in the early treatment group and 41 (4.1%) in the late treatment group. At 90 days, the difference in the rate of the composite outcome was -1.9%. In addition, recurrent ischaemic stroke at 30 days occurred in 14 patients (1.4%) in the early treatment group and 25 (2.5%) in the late treatment group, while—“most importantly”, according to Fischer—symptomatic ICH was similar across the groups, occurring in two patients (0.2%) in both.

“The study also suggests that the incidence of symptomatic intracerebral haemorrhage is low with early anticoagulation, if imaging-based classification is used,” stated Jesse Dawson (University of Glasgow, Glasgow, UK), who led ELAN alongside Fischer.

These findings have now also been published in the New England Journal of Medicine. As a next step, the researchers plan to explore whether the risk and benefit is similar in different subgroups of the ELAN trial population, especially in stroke patients who are more severely affected.


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