Severe aortic stenosis echocardiographic thresholds revisited

Abstract

Abstract Background In view of inconsistencies in threshold values of severe aortic stenosis (AS) hemodynamic indices, it is unclear what is the relative contribution of each variable in a binary classification of AS based on aortic valve replacement (AVR) indication. Purpose Assess relative discriminative value and optimal threshold of each constituent hemodynamic parameter for this classification and confirm additional prognostic value. Methods Echocardiography studies of 168 patients with ≥ moderate AS were included. AS types were dichotomized based on intervention implication into two groups: Group-A, comprising moderate and Normal-Flow Low-Gradient (NFLG), and Group-B, comprising High-Gradient (HG), Low Ejection Fraction Low-Flow Low-Gradient (Low EF-LFLG), and Paradoxical Low-Flow Low-Gradient (PLFLG) AS. Aortic valve area (AVA), Doppler velocity index (DVI), peak aortic velocity, mean gradient and stroke volume index were assessed for A/B Group discrimination value and optimal thresholds were determined. Dichotomized values were assessed for predictive value for AVR or death. Results C-statistic values for binary AS classification was 0.74–0.9 for the tested variables. AVA and DVI featured the highest score, and SVI the lowest one. AVA≤0.81 cm2 and DVI≤0.249 had 87.6% and 86% respective sensitivity for Group B patients, and a similar specificity of 80.9%. During a mean follow-up of 9.1±10.1 months, each of the tested dichotomized variables except for SVI predicted AVR or death on multivariate analysis. Conclusion An AVA value ≤0.81 cm2 or a DVI ≤0.249 threshold carry the highest discriminative value for severe AS in patients with aortic stenosis, translating into an independent prognostic value, and should be considered in clinical decisions. Funding Acknowledgement Type of funding sources: None. Echo variables correlation with Group BSurvival curves for individual AS types