P334 - PROGNOSTIC VALUE OF LEFT ATRIAL VOLUME INDEX IN PATIENTS WITH AORTIC VALVE STENOSIS

Background: Left atrial (LA) enlargement is a recognized marker of adverse outcomes in aortic stenosis (AS), yet current guidelines apply a uniform LA volume index (LAVI) threshold that ignores sex-related differences in cardiac remodeling. We aimed to characterize sex-specific associations between AS hemodynamic severity and LA remodeling, and to identify optimal LAVI thresholds for predicting long-term mortality in women and men with AS.

METHODS AND RESULTS: We retrospectively analyzed clinical and echocardiographic data from 1,503 consecutive patients (mean age 7112 years, 38% women) with at least mild AS (peak aortic jet velocity [Vpeak] >2.0 m/s or aortic valve area < 2cm2), preserved left ventricular ejection fraction (LVEF ≥50%), and no history atrial fibrillation. LAVI was measured using the biplane Simpson’s method. The primary endpoint was the incidence of all-cause death.
LAVI was significantly associated with AS severity (Vpeak: standardized-Beta: 0.17, p< 0.001), with a stronger association observed in women (sex interaction, p=0.04). After adjustment for age, LVEF, and comorbidities, women had higher LAVI than men for similar AS severity (e.g., at severe AS [Vpeak400 cm/s]: 34 ml/m2 vs 31 ml/m2, p< 0.001). During a mean follow-up of 3.82.4 years, 340 (22%) deaths occurred. Optimal sex-specific thresholds (i.e, with best sensitivity/specificity) of LAVI predicting 1-year mortality were higher in women (37 ml/m2) than men (33 ml/m2) (Figure Panel A and B). These sex-specific thresholds to define LA enlargement were significantly associated with mortality excess (Figure Panel C and D). In multivariable Cox model, LA enlargement defined using the proposed sex-specific thresholds remained significantly associated with increased risk of mortality (hazard ratio: 1.71 [95% CI, 1.34-2.19]; p< 0.001), and demonstrated superior prognostic performance compared to the uniform 34 ml/m2 cutoff (models AIC: 3324 versus 3332).

Conclusion: In this large AS cohort, LA remodeling is associated with AS severity, with women demonstrating both greater LA enlargement for the same AS hemodynamic severity and higher LA volume thresholds to predict mortality excess. These findings support the incorporation of sex-specific LA enlargement criteria for improved risk stratification in patients with AS.