Stroke Volume Adjusted to Afterload for Assessment of Cardiac Performance in Patients with Severe Aortic Stenosis and Preserved Left Ventricular Ejection Fraction

Abstract

Objectives: The aim of this study was to evaluate the relationship between valvular resistance and stroke volume (SV) and to assess SV adequacy to afterload in patients with severe aortic stenosis (AS) and normal left ventricular ejection fraction (LVEF). Methods: We assessed clinical characteristics and echocardiographic parameters in 44 patients with isolated severe AS and preserved LVEF. LV end-diastolic pressure (LVEDP) and LV mean diastolic pressure (LVMDP) were measured by cardiac catheterization. SV values were plotted in relation to valvular resistance. Patients were divided into 2 groups, with an SV that was higher (group 1) or lower (group 2) than the SV calculated by a regression equation using valvular resistance as the dependent variable. Results: At the same degree of valvular stenosis, the patients in group 1 exhibited better contractility as assessed by global longitudinal strain (p < 0.05), higher peak (p < 0.01) and mean gradient (p < 0.05), indexed SV (p < 0.001) and transvalvular flow (p = 0.01) than the patients in group 2, who had a higher heart rate (HR, p < 0.05), shorter ejection time (ET, p < 0.05) and more elevated LVEDP (p < 0.05) and LVMDP (p < 0.05). Conclusion: The presence of inappropriately decreased SV relative to afterload in patients with severe AS and normal LVEF was associated with lower contractility, higher HR, shorter ET and elevated LV diastolic pressure, which suggest failed hemodynamic adaptation to afterload.