Structural and Functional Correlates of Gradient-Area Patterns in Severe Aortic Stenosis and Normal Ejection Fraction

OBJECTIVES The authors sought to characterize the functional and structural myocardial phenotypes of patients with moderate-to-severe aortic stenosis (AS) and to determine whether severe paradoxical tow-gradient AS (LG-AS) is specifically associated with left ventricular (LV) remodeling and fibrosis. BACKGROUND Recently, it was suggested that severe paradoxical LG-AS is a more advanced form of AS, with greater reduction of longitudinal deformation, adverse LV remodeling, and more interstitial fibrosis. METHODS The study population includes 147 patients with moderate-to-severe AS and a normal LV ejection fraction, and 75 normal control subjects. They prospectively underwent 2-dimensional speckle-tracking echocardiography and cardiac magnetic resonance to evaluate myocardial deformation, LV remodeling, and age- and sex-adjusted extravascular volume fraction (ECV, %). Among AS patients, 18 had moderate AS, 74 had severe high-gradient AS (HG-AS), and 55 had severe paradoxical LG-AS. RESULTS Reduced longitudinal and circumferential deformation was observed in 21% and 6% of the AS patients, respectively. Multivariate analyses identified increased ECV (beta = 1.99; p = 0.001) and the absence of normal LV geometry (beta = 1.37; p = 0.007) and as independent predictors of reduced longitudinal deformation. Increased ECV was an independent predictor of reduced circumferential deformation (beta = 2.19; p = 0.001). Over a median follow-up of 29 months, reduced longitudinal deformation (hazard ratio: 0.82; p = 0.023) and higher transvalvular gradients (hazard ratio: 1.05; p < 0.001) increased the risk of death or need for aortic valve replacement. LV hypertrophy was more frequently observed among patients with severe HG-AS (65%) than among the other AS patients (14%; p < 0.001). On average, ECV was within normal limits and did not differ among gradient-area subgroups. When present, increased ECV was associated with reduced longitudinal deformation. CONCLUSIONS This study's data show that patients with severe paradoxical LG-AS less frequently display reduced longitudinal deformation, LV hypertrophy, or myocardial fibrosis than patients with HG-AS. Also, interstitial fibrosis only occurs when reduced longitudinal deformation and severe HG-AS are present together. Finally, this study suggests that reduced longitudinal deformation and higher transvalvular gradients adversely affect patients' outcomes. (C) 2021 by the American College of Cardiology Foundation.

Automated summary

The study found that patients with severe paradoxical LG-AS less frequently exhibit reduced longitudinal deformation, LV hypertrophy, or myocardial fibrosis compared to those with HG-AS. Additionally, interstitial fibrosis only occurs when reduced longitudinal deformation and severe HG-AS are present together. The study also suggests that reduced longitudinal deformation and higher transvalvular gradients adversely impact patients' outcomes.