Dissecting Myocardial Mechanics in Patients with Severe Aortic Stenosis: 2-Dimensional vs 3-Dimensional-Speckle Tracking Echocardiography

Background: Aortic stenosis (AS) causes left ventricular (LV) pressure overload, leading to adverse LV remodeling and dysfunction. We examined the impact of severe AS and its consequent increase in LV afterload on myocardial deformation and rotational mechanics by 2-dimensional (2D) and 3-dimensional (3D) speckle-tracking echocardiography. Methods: We prospectively measured various strain parameters in 168 patients (42% female, mean age 72±12 years) with severe AS and LV ejection fraction (EF) ≥50%, and compared them to normal values found in literature. 2D and 3D images were analyzed for global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), basal rotation, apical rotation, and peak systolic twist. We further assessed the degree of concordance between 2D and 3D strain, and examined their association with measures of LV preload and afterload. Results: Patients with severe AS exhibited significantly lower GLS and GRS but higher GCS, apical rotation, and twist by 2D and 3D echocardiography compared with published normal values (P=0.003 for 3D twist,P<0.001 for all others). There was modest agreement between 2D and 3D GLS measurements (concordance correlation coefficient 0.49, 95% confidence interval 0.39-0.57). GLS was modestly correlated with valvulo-arterial impedance, a measure of LV afterload (r=0.34, p<0.001 for 2D and r=0.23, p=0.003 for 3D). Conclusion: Patients with severe AS demonstrate lower-than-normal GLS and GRS as a result of increased afterload but appear to compensate with higher-than-normal GCS, apical rotation, and twist in order to maintain a preserved LVEF. Our study provides, to our knowledge, the most comprehensive analysis to date of myocardial deformation and rotational mechanics by 2D and 3D speckle-tracking echocardiography in patients with severe AS and preserved LVEF.