Abstract 12213: A Description of Left Atrial Appendage Morphologies by Race

Abstract

Introduction : The left atrial appendage (LAA) is the origin of most thromboemboli in patients with atrial fibrillation (AF). Certain LAA morphologies are associated with higher risk of thrombus formation and stroke. Blacks with AF suffer more ischemic strokes than non-Blacks despite adjustment for conventional stroke risk factors and differences in anticoagulation prescription. The association of certain LAA morphologies with race as a contributing explanation for the racial difference in stroke risk has not been examined. We hypothesized that, among those with AF, Blacks have higher risk LAA morphologies compared to non-Blacks. Methods : We performed a retrospective analysis of consecutive patients with AF who underwent a contrast-enhanced CT scan in preparation for Watchman device placement to determine LAA morphology. Based on prior literature, we assigned a score to each morphology based on relative risk of stroke associated with each morphology: chicken wing, 1 (lowest risk, reference); windsock or cactus, 4; and cauliflower, 8. Mean scores among Blacks vs non-Blacks, defined as White, Asian, or Hispanic, were compared using Students T-test. Results : Among 85 patients (Black, n=36), there was no significant difference in the proportion of individuals with the low risk chicken wing morphology between races (29% Black versus 36% non-Black, p = 0.69). However, Blacks were more likely to have the high risk cauliflower morphology (n=5, 6% versus n=1, 1%, p=0.04). The summative mean score for morphology-associated stroke risk was higher among Blacks (2.1 vs 2.5, p=0.017) ( Figure ). Conclusions : Black patients with AF had higher-risk LAA morphologies compared to non-Black patients. These findings may explain the previously observed racial differences in AF-associated stroke risk.Figure: Distribution of LAA morphologies by Black versus Non-Black and difference in summative relative risk between Black and Non-Black patients.