Left Atrial Expansion Index for Ischemic Stroke Prediction in Patients with Atrial Fibrillation

Background: The efficacy of the left atrial (LA) expansion index (LAEI) to predict cerebral ischemic events in patients with atrial fibrillation (AF) is unknown. Methods: We enrolled 177 patients with AF (88 with paroxysmal AF and 89 with persistent AF) and a baseline CHA2DS2-VASc score (at enrollment) of 3.6 +/- 2.3. Comprehensive echocardiography was performed at enrollment. The LAEI was calculated as (Vol(max) -Vol(min)) x 100%/Vol(min), where Vol(max) and Vol(min) denoted maximal and minimal LA volumes, respectively. The study endpoint was ischemic stroke. Stroke subtypes were classified into cardioembolic stroke (CE), non-CE with determined mechanism (NCE), embolic stroke of undetermined source (ESUS), or transient ischemic attack (TIA). Results: Over a mean 9.9-year follow-up period, 44 (24.9%) of the patients reached the endpoint (24 with CE, 4 with NCE, 6 with ESUS, and 10 with TIA). The LAEI was lower in the stroke group than in the non-stroke group. Stroke incidence in the lowest LAEI quartile was much higher than that in the other LAEI quartiles; the 10-year cumulative stroke risk was 15.9% (14/88) and 33.7% (30/89) in the patients with paroxysmal and persistent AF, respectively. An LAEI of < 35% predicted the presence of stroke with 77% sensitivity and 78% specificity. In multivariable analysis, the LAEI was independently associated with ischemic stroke (hazard ratio 0.952 per 1% increase, 95% confidence interval 0.932-0.97 1, p < 0.0001). Conclusion: The LAEI is a useful predictor of ischemic stroke in patients with AF.