New pathways identified for stroke in people with atrial fibrillation

Congratulations to UCD School of Medicine’s Dr John McCabe, Dr Tim Cassidy, Dr Pádraig Synnott, Professor Peter Kelly and all involved on their paper published in Neurology titled, ‘Clinical and Biomarker Determinants for Recurrent Stroke in Patients With Atrial Fibrillation'.

This UCD-led research has identified new pathways for stroke in people with atrial fibrillation (AF). 1 in 3 strokes are caused by AF. Whilst prevention medications are effective for most patients, the risk of stroke remains very high in some individuals. In the current research published in the journal Neurology, Dr Helen Cheung and Dr Marianne Foley report how multiple complex, inter-related disease mechanisms culminate in higher stroke risk for some patients with AF.

Despite effective secondary prevention, including oral anticoagulant (OAC) therapy, the risk of recurrent stroke (RS) in patients with atrial fibrillation (AF) remains substantial with an annualised risk of 3.2%–6.5% per year. The reasons for this high residual risk are unclear. There is growing need for improved risk prediction tools to identify patients at greatest risk of RS in AF and to find new therapeutic targets for secondary prevention. The team’s objective was to perform a systematic review to investigate the association of clinical factors and echocardiographic, blood, and neuroimaging biomarkers, with stroke recurrence after AF-related stroke.

Assistant Professor at UCD School of Medicine and consultant geriatrician at the Mater Misericordiae University Hospital, Dr John McCabe, led the work and states, "Millions of people suffer a stroke every year due to AF. We urgently need to develop new treatments for this condition. This recent work will hopefully be the first step in strategies to identify high-risk patients, who may benefit from emerging treatments. In the coming years, we anticipate greater research investment in this area will transform the landscape of treating this condition."

The research team searched Embase/Ovid Medline until August 2023. Studies were included irrespective of OAC use. Risk ratios (RRs) were pooled using random effects. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.

Of 5,427 records searched, 42 reports from 28 studies including 52,798 patients (5,046 RS events during follow-up) were identified. In addition to the CHA2DS2-Vasc score and its individual components, the clinical factors associated with recurrence were a qualifying stroke despite OAC, sustained, hyperlipidemia, chronic kidney disease, and malignancy. NIH Stroke Scale scores and Asian ethnicity were associated with a reduced risk of recurrence. Known AF was not associated with a higher risk of stroke compared with AF detected after stroke. Neuroimaging markers associated with RS included chronic lacunar or embolic appearing infarcts and cerebral microbleeds. Echocardiographic markers included atrial size, intracardiac thrombus, spontaneous left atrial appendage echocardiographic contrast, or low LAA intensity variation. Data were limited for blood biomarkers.

The paper can be found online here.