Acceleration Time and Ratio of Acceleration Time to Ejection Time in Aortic Stenosis: New Echocardiographic Diagnostic Parameters

Abstract

Inconsistencies between gradients and aortic valve area are frequent in the echocardiographic evaluation of aortic stenosis (AS). Assessing AS severity is essential for the correct management of the disease. The aim of this study was to evaluate whether ejection dynamics, particularly acceleration time (AT) and the ratio of AT to ejection time (ET), could be diagnostic parameters in patients withAS. Patients with AS (aortic peak velocity>2m/sec) were prospectively enrolled. Quantitative echocardiographic Doppler parameters including ejection dynamics (AT, ET, and AT/ET ratio) as well as conventional and clinical parameters were analyzed. AT, ET, and AT/ET ratio were calculated in different stages ofAS. A receiver operating characteristic curve was plotted to determine the best cutoff value to identify severe AS. Two hundred sixty-two patients were included (mean age, 75±8years; 54% women), of whom 109(42%) had severe AS, 99 (38%) had moderate AS, 22 (8%) had mild AS, 24 (9%) had classical low-flow, low-gradient severe AS, and eight (3%) had paradoxical low-flow, low-gradient severe AS. AT was higher in patients with higher levels of severity of AS (65±16 vs 82±19 vs 109±23msec, P<.001) as well as AT/ET ratios (0.22±0.05 vs 0.29±0.07 vs 0.37±0.06, P<.001). Using a cutoff of 94msec, AT had sensitivity of 71% and specificity of 81% for severe AS; using a cutoff of 0.35, the AT/ET ratio had sensitivity of 59% and specificity of 86%. On multivariate analysis, AT was associated with effective orifice area (B=-0.64, P<.001) and ET with heart rate (B=-0.62, P<.001) and age (B=0.30, P=.04). Ejection dynamics parameters, such as AT and AT/ET, can help evaluate AS severity.