Atrial fibrillation patients at increased risk of cognitive impairment, dementia: Study
05 Nov 2014
The increased risk of stroke in people with atrial fibrillation (AF) was well known, with the stroke risk linked to an increased risk of cognitive impairment and dementia, Forbes reported.
What was less well known was that people with AF had an increased risk for cognitive impairment independent of their stroke risk.
According to a new study published in Annals of Internal Medicine, there was evidence that this increased risk might be linked to a higher rate of asymptomatic silent strokes in AF patients.
A systematic review and meta-analysis of observational studies utilising CT or MRI uncovered the prevalence of silent cerebral infarctions (SCIs) in 505 people with AF and 3,902 in people without AF.
Earlier studies using autopsies were discarded due to their low quality. Patients with AF showed over a two-fold increase in risk. SCIs were found in 45.4 per cent of people with AF as against 15.63 per cent of people without AF.
The study was not able to evaluate whether anticoagulants, which were the cornerstone of stroke prevention in AF patients, cut the risk of SCI. According to the authors, randomised trials needed to be performed to assess whether SCI should be incorporated in the standard AF risk evaluation score to evaluate eligibility for anticoagulation therapy.
According to review author Dr Shadi Kalantarian, a resident at the Yale School of Medicine in New Haven, Connecticut, patients with atrial fibrillation were at higher risk of developing silent strokes, www.health.usnews.com reported.
Atrial fibrillation, an electrical disorder causes the upper chambers of the heart to contract quickly and irregularly and the abnormal contractions allowed blood to pool and coagulate in the heart, forming clots that could cause a stroke if they broke off and were carried into the brain.
The researchers reviewed 11 previously published reports that considered the association between atrial fibrillation and silent strokes in a total of about 5,000 patients.
The type of study, called meta-analysis, involves culling of published studies in hopes of finding patterns supporting a conclusion or trend. By finding similar trends in a variety of studies, the conclusions could be stronger than what could be provided by a single study.
While the analysis uncovered an association between atrial fibrillation and an increased risk of silent strokes, it did not prove a cause-and-effect link.
According to Dr Gregg Fonarow, a professor of cardiology at the David Geffen School of Medicine at the University of California, Los Angeles, atrial fibrillation was a substantial risk factor for stroke, with patients with atrial fibrillation having a fivefold increased risk of symptomatic stroke.
