Going beyond classic echo in aortic stenosis: left atrial mechanics, a new marker of severity

BACKGROUND: There is limited information regarding left atrial (LA) mechanics in aortic valve stenosis (AS). We assessed LA mechanics in AS through speckle-tracking echocardiography (STE) according to severity and prognosis. METHODS: We included 102 patients diagnosed with severe AS (sAS) and 80 patients with moderate AS (mAS), all with preserved ejection fraction and no coronary artery disease. LA mechanics and left ventricular global longitudinal strain (LV-GLS) were assessed by STE. The cohort was followed-up for a median of 30 (IQR 12.6-50) months, and outcomes were determined (combined outcome of HF, death, and aortic valve replacement). RESULTS: In our sample set, values of LV-GLS (- 18.5% vs - 17.1, p = 0.025), E/e' ratio (15.8 vs 18.4, p = 0.03), and global LA mechanics (LA ɛsys, 23% vs 13.8%, p < 0.001) were worse for sAS compared to those for mAS. However, LA ɛsys (AUC 0.85, 95% CI 0.78-0.90, p < 0.001), ɛe (AUC 0.83, 95% CI 0.75-0.88, p < 0.001), and ɛa (AUC 0.80, 95% CI 0.70-0.84, p < 0.001) were the best discriminators of sAS, with sensitivities higher than 85%. LA ɛsys showed a stronger correlation with both aortic valve area (r2 = 0.6, p < 0.001) and mean LV/aortic gradient (r2 = 0.55, p < 0.001) than LV-GLS (r2 = 0.3 and r2 = 0.25, p = 0.01). Either LV-GLS or LA ɛsys, but not the E/e' ratio, TAPSE, or RV/RA gradient, were a significant predictors of the combined outcome. CONCLUSIONS: LA global strain was the best discriminator of severity, surpassing E/e' ratio and LV-GLS, and a significant predictor of prognosis in AS.