AF-associated stroke ‘a distinct pathophysiologic and clinical entity’
MedWire News: Strokes associated with atrial fibrillation (AF) account for around one-third of the total and tend to be particularly severe, disabling, and likely to recur, research suggests.
The study authors say that targeted strategies to increase anticoagulation rates “may provide a substantial benefit to prevent severe disabling stroke at a population level.”
Peter Kelly (Mater University Hospital, Dublin, Ireland) and team analyzed data from the North Dublin Population Stroke Study, a prospective cohort study that is monitoring the frequency and outcomes of stroke and transient ischemic attack (TIA) in North Dublin, a city with a population of 294,592.
Over the 1-year study period there were 568 new strokes or TIAs, 485 of which were first-ever, Kelly’s team reports in the journal Cerebrovascular Diseases.
AF was detected in 31.2% of all cases and in 28.7% of all first-ever strokes. Of note, nearly half of AF cases (45.7%) were newly diagnosed following the stroke.
Compared with non-AF-strokes, AF-associated strokes had a “distinct profile”, say Kelly et al, being more likely to be ischemic, more likely to be total or partial anterior circulation infarcts, and less likely to be lacunar infarcts.
Furthermore, patients with AF-associated stroke were older than those without AF (76.6 vs 68.4 years), had higher rates of coronary artery disease, lower rates of smoking, and were more likely to have had a prior stroke or TIA (21.9% vs 12.8%).
Finally, the team found that AF-associated strokes tended to be more severe than those not associated with AF, with greater acute neurological impairment (median National Institutes of Health Stroke Scale scores 6 vs 4) and greater functional disability in both the acute phase (median modified Rankin Scale score 4 vs 3) and at 7, 28, and 90 days.
There was no difference in 90-day case-fatality or recurrence between AF and non-AF strokes, however.
Kelly et al say that the proportion of AF-associated stroke in this study is higher than previously reported, possibly reflecting their use of more rigorous case-ascertainment methods.
“Our data support the concept of AF-associated stroke as a distinct pathophysiological and clinical entity, with a characteristic profile of severe, recurrent and disabling stroke,” they write.
“Our data also suggest that AF-associated stroke may be more common than previously considered, occurring in approximately one third of all ischemic strokes.”
They conclude that there exists a “substantial opportunity” for improved stroke prevention at a population level, noting that opportunistic screening of older individuals for AF is “feasible, relatively inexpensive and effective.”
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By Joanna Lyford