Karim Mahawish: Ischaemic Stroke Despite Anticoagulation in Atrial Fibrillation
Karim Mahawish, Senior Medical Officer in Geriatric, General and Stroke Medicine at Counties Manukau Health, shared a post on LinkedIn about a recent article he and his colleagues co-authored, published NZMJ, in adding:
” ‘ Breakthrough stroke’ is often not true anticoagulant failure.
Pleased to share our new publication in the New Zealand Medical Journal examining ischaemic stroke/TIA occurring despite oral anticoagulation in patients with atrial fibrillation.
In a real-world Auckland cohort of 179 anticoagulated patients with AF who presented with IS/TIA, most events were not simply ‘drug failure’:
77percent were adjudicated as cardioembolic, but many were associated with anticoagulant under-exposure, including missed doses, under-dosing, or low laboratory markers of anticoagulant effect.
Conversely, patients with good anticoagulant control were more likely to have a non-cardioembolic mechanism, with good control independently associated with non-cardioembolic IS/TIA in adjusted analysis.
The clinical message is simple but important: when stroke occurs despite anticoagulation, we should not reflexively escalate antithrombotic therapy. We need careful aetiological assessment, review of adherence and dosing, and targeted secondary prevention.
As anticoagulant uptake improves, the prevention challenge increasingly shifts from ‘was anticoagulation prescribed?’ to ‘was anticoagulation effectively delivered?’
Grateful to my co-authors Valery Feigin, Rita Krishnamurthi and Harvey White, and to the ARCOS team.”
Title: Mechanisms of ischaemic strokes and transient ischaemic attacks despite oral anticoagulation in patients with atrial fibrillation
Authors: Mahawish KM, Feigin V, Krishnamurthi R, White HD. Mechanism

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