Left Atrial Diverticula Detected on Cardiac CT in Patients With Acute Ischemic Stroke: A Substudy of Mind the Heart

BACKGROUND: Left atrial (LA) diverticula are focal outpouchings of the LA wall and may increase ischemic stroke risk. We studied recurrent ischemic stroke in patients with acute ischemic stroke and LA diverticula detected on cardiac computed tomography. METHODS: We used data from a prospective cohort study of patients with acute ischemic stroke undergoing cardiac computed tomography acquired during the acute stroke imaging protocol. Cardiac radiologists systematically assessed the presence and characteristics of LA diverticula, defined as LA wall outpouchings with a length/ostium width ratio >0.5 and length ≥3 mm. We compared recurrent ischemic stroke and functional outcome (modified Rankin Scale) after 2 years between patients with and without LA diverticula, adjusting for age, history of atrial fibrillation and ischemic stroke, and anticoagulation use. RESULTS: Of 447 included patients (median age 72 [interquartile range (IQR), 62–81], 59% male), 126 (28%) had LA diverticula: median length 6 mm (IQR, 4–8), width 5 mm (IQR, 4–7), and volume 113 mm3 (IQR, 52–254). There was no statistically significant difference in age (median 70 [IQR, 58–79] versus 73 [IQR, 63–81]; P=0.06), sex (64% versus 57% male; P=0.28), history of ischemic stroke (21% versus 17%; P=0.48), atrial fibrillation (11% versus 19%; P=0.09), or baseline National Institutes of Health Stroke Scale score (median 5 [IQR, 2–14] versus 5 [IQR, 3–14]; P=0.54) between patients with and without LA diverticula, respectively. Recurrent ischemic stroke was more common in patients with LA diverticula (18/124 [15%] versus 24/314 [8%], adjusted hazard ratio, 2.01 [95% CI, 1.08–3.77]), and recurrence risk increased with diverticulum volume (adjusted hazard ratio, 1.02 [95% CI, 1.01–1.03] per 10 mm3). Functional outcome was better in patients with diverticula (median modified Rankin Scale score of 2 [IQR, 1–3] versus 3 [IQR, 1–6], adjusted common odds ratio, 0.62, [95% CI, 0.42–0.92]). CONCLUSIONS: LA diverticula are a common finding on cardiac computed tomography in patients with acute ischemic stroke, and the risk of recurrent ischemic stroke was increased in these patients, particularly in those with larger diverticula. Atrial diverticula may be a risk factor for recurrent ischemic stroke.