Comparison of Echocardiographic Variables in Patients With Severe Aortic Stenosis and Preserved Ejection Fraction Grouped by Flow and Gradient

The pathophysiology of severe aortic stenosis (AS) is complex with vascular, valvular, and myocardial components. To better define this process, we compared echocardiographic and clinical variables in patients with severe AS and preserved EF according to flow and gradient. We retrospectively studied the clinical and echocardiographic data of 287 patients (mean age 76 ± 11 years, 57% men) from 2012 to 2017 with severe AS (indexed aortic valve area <0.6 cm²/m²) and preserved ejection fraction (>50%). Patients were divided into 4 groups based on flow (stroke volume index < or ≥35 ml/m²) and mean aortic pressure gradient (< or ≥40 mm Hg): normal flow, high gradient (NFHG), normal flow, low gradient (NFLG), low flow, high gradient (LFHG) and low flow, low gradient (LFLG). Among patients with severe AS, 23% had NFHG, 44% had NFLG, 10% had LFHG, and 23% had LFLG. Only diabetes was marginally significantly different among the clinical variables. Aortic valve area index was largest in NFLG and smallest in LFHG (p < 0.001 for pairwise comparisons). Valvuloarterial impedance was highest in LFHG (p < 0.01 for pairwise comparisons). Systemic arterial compliance was lower and systemic vascular resistance was higher in low flow compared with normal flow groups. In conclusion, LFHG had the smallest valve area index along with markers of increased vascular resistance combined with high gradients, which suggests a unique pathophysiology in this group of severe AS patients with preserved EF.