Left atrial appendage morphology as a cardio-embolic risk factor in patients with stroke of undetermined source

Background: Left atrium (LA) volume and function and certain left atrial appendage (LAA) morphologies are known to be strongly associated with the risk of thrombus formation and thromboembolism in patients with atrial fibrillation (AF). Little is known about the role of LA parameters and LAA morphology in patients with Embolic Stroke of Undetermined Source (ESUS).

Purpose: To assess LA volume and function and LAA morphologies in ESUS patients and the potential association with cardioembolic risk.

Methods: Twenty consecutive patients with ESUS who underwent contrast enhanced electrocardiogram-gated computed tomography (CT) as part of stroke etiology evaluation were matched by age and gender to patients with and without history of AF (twenty in each group) who had CT as part of standard evaluation before transcatheter aortic valve implantation. LA maximum (LAVmax) and minimum (LAVmin) volumes and function, measured as total emptying volume (LAEV) and total emptying fraction (LAEF) were assessed, and three- dimensional structures of the LA and LAA were constructed using the volume-rendered post-processing technique.

Results: The mean age of patients was 75.9±8.61, 76.1±8.52, 77.8 ±7.72) in the ESUS, AF and non-AF groups, respectively, with 11(55%) females in each group. Compared to patients with ESUS, patients with AF showed significantly greater LAVmax (100.59 ± 31.59 ml vs.155.78± 63.15 ml, respectively, , p=0.001) and LAVmin (71.38 ± 30.69 ml vs. 140.73 ± 64.60 ml; respectively, p <0.001), while LAV max and LAVmin were similar, in patients with ESUS and non-AF . The distribution of LAA morphologies significantly differed between patients with ESUS and patients with AF and non-AF: 1 (5%) vs. 9 (45%) chicken-wing; 14 (70%) vs. 8 (40%) cauliflower; and 5 (25%) vs. 3 (15%) Cactus; respectively.

Conclusion: LA appendage morphology, but not LA volume, seems to be associated with ESUS. LAA morphologies with multiple lobes, cauliflower and cactus, seems to be associated with ESUS.