Early Blood-Thinning Therapy Demonstrates Safety and Effectiveness for Stroke Patients

Recent research led by University College London has revealed that initiating blood-thinning treatment shortly after a stroke caused by atrial fibrillation is both safe and beneficial. The study indicates that starting direct oral anticoagulants (DOACs) within four days of a stroke significantly lowers the risk of subsequent strokes without increasing the chance of bleeding in the brain.

The findings, published in The Lancet and part of the larger CATALYST trial, analyzed data from four randomized clinical studies involving 5,441 patients across the UK, Switzerland, Sweden, and the US. All participants had suffered a recent ischemic stroke linked to atrial fibrillation, a common heart rhythm disorder that elevates the risk of clot formation and stroke.

Traditional guidelines recommend waiting at least five days before beginning anticoagulants to prevent bleeding risks. However, this new evidence suggests that earlier intervention — within four days — is both safe and more effective in preventing another stroke, showing a 30% reduction in recurrence risk compared to delayed treatment.

Atrial fibrillation affects over 1.6 million people in the UK and significantly increases stroke risk, with those affected being five times more likely to have a stroke. The use of anticoagulants is well-established for stroke prevention in these patients, but the timing of initiation post-stroke has been uncertain.

The study’s senior researcher, Professor David Werring, emphasized that early treatment could change current clinical practices, enhancing patient outcomes. Dr. Hakim-Moulay Dehbi, the study’s lead statistician, highlighted that combining data from multiple trials strengthened the confidence in these findings.

The research also builds on prior work from the OPTIMAS study, which assessed similar timing strategies across 3,621 patients in UK hospitals, supporting the safety of early anticoagulation. Overall, these findings could lead to updates in medical guidelines, ensuring timely treatment to reduce recurrent strokes while maintaining safety.

Limitations include variability in stroke severity among participants and the focus mainly on patients with moderate strokes, meaning applicability to all cases requires further investigation.

The authors hope these results will advance understanding and application of early anticoagulant therapy to improve stroke prevention worldwide.