Sex and Racial Differences in Left Atrial Appendage Morphology

Background Black and female patients with atrial fibrillation have more strokes. Certain left atrial appendage (LAA) morphologies impose a higher stroke risk. Whether anatomic differences in LAA morphology are associated with race or sex remains unexplored. Methods We identified consecutive patients with computed tomography for LAA morphology and categorized each patient by self‐reported race (Black versus non‐Black) and sex. Each LAA morphology was assigned a score based on published relative LAA thrombus risk (lowest to highest: “chicken wing,” “windsock” and “cactus,” “cauliflower”). Scores and prevalence were compared across races and sexes using a Wilcoxon rank‐sum test and Fisher’s exact test, respectively. Logistic regression was performed to find the association of race (adjusting for sex) and sex with higher risk LAA morphologies. Results Among 211 patients (27% Black, n=58; 47% female, n=100), there was no difference in the projected hypothetical stroke risk across race or sex (median for Black versus non‐Black patients: 1 [interquartile range, 1–4] versus 1 [interquartile range, 1–1], P =0.11; median for women versus men: 1 [interquartile range, 1–4] versus 1 [interquartile range, 1–4], P =0.62). The highest risk LAA morphology, cauliflower, had greater odds of being present in Black versus non‐Black patients (unadjusted odds ratio [OR], 6.0 [1.4–25.1], P =0.049; adjusted OR, 4.8 [1.1–20.9], P =0.035). Although cauliflower LAA morphology was more prevalent in women (n=7 [9%] versus n=2 [2%] in men; P =0.063), this difference nor odds of cauliflower LAA morphology being present in women were statistically significant. Conclusions The highest risk LAA morphology, cauliflower, demonstrated greater odds of being present in Black patients versus non‐Black patients. The difference in women versus men did not reach statistical significance. Although the study was underpowered to make the findings declarative, these results are provocative regarding the differential stroke risk across races and sexes.