Usefulness of atrial function for risk stratification in asymptomatic severe aortic stenosis

Aim: We aimed to evaluate the usefulness of left atrial (LA) mechanics and stiffness over global left ventricular (LV) longitudinal strain (GLS) for risk stratification in severe aortic stenosis (AS).

Methods: From a cohort of 89 prospective asymptomatic patients with severe AS and normal LV ejection fraction, 82 (32 men, mean age 73±10 years) truly asymptomatic patients, scheduled after a negative exercise echocardiogram, were enrolled. Forty age- and gender-matched prospective, asymptomatic subjects served as controls. Predefined end points were the occurrence of symptoms (dyspnea, angina, syncope), and death during follow-up.

Results: At study entry, patients had: impaired LV GLS (p=0.001), reduced LA reservoir (p<0.001), high LA stiffness (p<0.001), and increased valvulo-arterial impedance (p<0.001) compared to controls. During follow-up [16±14.9 months (ranging from 1 month to 4.2 years)], 53 patients (64.6%) reached one of the endpoints. Patients with events showed lower LV GLS (p>0.001), lower LA reservoir (p<0.001), and greater LA stiffness (p<0.001) than those asymptomatic. On univariate Cox regression analysis, LV GLS (p<0.001), LA reservoir (p<0.001), and LA stiffness (p=0.004) were strong predictors of adverse events. Kaplan-Meier curves showed that event-free survival was significantly higher in patients with a LV GLS ≥16.8% [p<0.001; area under the curve (AUC)=0.922; sensitivity=86%, specificity=80%], a LA reservoir ≥19.8% (p=0.001; AUC=0.860, sensitivity=71%, specificity=84%), and a LA stiffness <0.78 (p<0.001; AUC 0.819, sensitivity 70%, specificity 89%). On multivariate analysis, only LV GLS remained significantly associated with patients' prognosis (hazard ratio=1.49, 95% CI=1.11-2.01, p=0.008).

Conclusions: In asymptomatic patients with severe AS, an efficient cardiovascular system is based on an effective atrial-ventricular interplay. LA function assessment is useful for early identification of risk in these patients. LV GLS however was confirmed to be the best predictor of patients' outcome.