Abstract 12674: Left Ventricular Myocardial Strain Gradient on a Novel Multi-layer Transthoracic Echocardiography Technique Positively Correlated With Degree of Severe Aortic Stenosis

Abstract

Introduction: A recently developed transthoracic echocardiography (TTE) technique enables detailed myocardial multi-layer analysis of left ventricular (LV) endocardial, epicardial and whole transmural layer strain. Hypothesis: Myocardial strain gradient, defined as endocardial/epicardial strain may influence aortic stenosis (AS) severity. To probe the mechanism behind AS severity we measured myocardial strain gradients in severe AS subjects with preserved LV ejection fraction (LVEF) using a novel, multi-layer speckle tracking TTE technique. Methods: 36 severe AS subjects (19 male, 77±7 years, LVEF >50%, transaortic maximum velocity 4.8±0.6m/s, aortic valve area index (AVAI) 0.45±0.11 cm2/m2) underwent TTE (Vivid E9, GE Healthcare). Apical 4-, 2-, and 3-chamber GLS views and parasternal short axis GCS views at the level of the mitral valve, papillary muscle, and apex were acquired. GLS was defined as all 17 averaged LV segments. GCS was defined as averaged LV segments at the level of the mitral valve, papillary muscle, and apex, respectively. Furthermore strain measurements of whole, endocardial, and epicardial layers were performed. Myocardial strain gradient was defined as: endocardial/epicardial strain. Results: Absolute value of averaged endocardial layer 2D LV GLS was significantly greater than that in the epicardial layer (P<0.001). Absolute values of endocardial layer GCS at all levels were significantly greater than those of the epicardial layer(all P<0.001). The GLS, but not the GCS at any levels, gradient significantly positively correlated with transaortic maximum velocity (R=0.404, P=0.015) and negatively correlated with AVAI (R=-0.463 P=0.005). Conclusions: In severe AS subjects with preserved LVEF, the LV GLS gradient positively correlated with transaortic maximum velocity and negatively correlated with AVAI. Therefore GLS gradients may influence AS severity.