Evaluation of left atrial function in patients with severe aortic stenosis with preserved ejection fraction based on real-time three-dimensional automated left atrial quantification technique.

Background: Aortic stenosis (AS) is a prevalent valvular heart disease with increasing incidence in aging populations. Mild AS is often asymptomatic with a favorable prognosis, whereas symptomatic severe AS progresses rapidly and carries high mortality. Although conventional echocardiography typically uses left ventricular ejection fraction (LVEF) to assess left ventricular (LV) systolic function, its sensitivity in detecting subclinical myocardial damage in AS patients remains limited. In this study, we used real-time 3-dimensional (3D) automatic left atrial quantitative (RT-3D Auto LAQ) technique to evaluate left atrial (LA) function in severe AS patients with preserved ejection fraction, investigate the diagnostic efficacy of LA functional parameters for this condition, and identify the positive predictors of concurrent heart failure symptoms. Methods: A total of 56 patients admitted to the Fourth Affiliated Hospital of Harbin Medical University who were diagnosed as having severe AS with ejection fraction ≥50% were included as the case group and divided into subgroups A and B according to New York Heart Association (NYHA) cardiac function classification. Subgroup A comprised NYHA cardiac function class I and II, subgroup B comprised NYHA cardiac function class III and IV, and an additional 56 age- and gender-matched healthy patients were selected as the control group. The parameters of the case group and the control group, subgroups A and B were recorded and compared, and the parameters were statistically analyzed. The factors associated with the development of grade III and IV heart failure in patients with severe AS with predicted ejection fraction retention were determined by plotting the receiver operating characteristic (ROC) curve and logistic regression analysis. Results: ROC curve analysis: the ROC curves of LA emptying rate parameters and strain parameters showed that the area under the curve (AUC) of left atrial storage period strain (LASr) and left atrial expansion index (LAEI) in predicting NYHA III and IV in patients with severe AS with preserved ejection fraction was relatively large, which were 0.855 and 0.778, respectively. The cutoff values were 16.5% and 97%, respectively. The sensitivity was 76.7% and 80%, respectively. The specificity was 80% and 65.4%, respectively, and the Youden index was 0.575 and 0.454, respectively. Logistic regression analysis: among the LA volume, emptying rate parameters, and strain parameters, LASr and LAEI were positive predictive factors for severe AS patients with preserved ejection fraction for the development or presence of class III and IV heart failure. Conclusions: Application of the real-time 3D Auto LAQ technique confirmed impaired LA three-phase function and volume enlargement in severe AS heart failure patients with preserved ejection fraction. Among the LA emptying rate parameters and strain parameters, LASr and LAEI correlated with the development of class III or IV heart failure.