Left ventricular systolic dyssynchrony index and endothelial dysfunction parameters as subclinical predictors of cardiovascular involvement in patients with beta‐thalassemia major

Abstract

Cardiovascular iron load is the leading cause of morbidity and mortality in beta-thalassemia major (β-TM). However, many patients remain asymptomatic until the late stage. In this cross-sectional study, we investigated the role of three-dimensional (3D) echocardiography and endothelial dysfunction parameters in asymptomatic β-TM patients, and the relationship between these parameters and cardiac magnetic resonance imaging (MRI) T2* value. A total of 51 asymptomatic β-TM patients receiving regular blood transfusions were divided into two groups based on cardiac MRI-T2* values (MRI-T2*<20ms and ≥20ms), which MRI-T2*<20ms determines myocardial iron load and evaluated by two-dimensional (2D) and 3D-echocardiography including endothelial dysfunction parameters. The relationships between ferritin levels, 2D and 3D-echocardiography measurements, endothelial dysfunction parameters, and cardiac MRI-T2* values were investigated. All left ventricle ejection fraction (LVEF) obtained by 2D-echocardiography were normal (≥50%). LVEF-3D (53.25±2.33 vs. 58.81+1.02), SDI12 (6.53±0.56 vs. 2.85+0.48), and SDI16 (7.65±0.75 vs. 3.26+0.49) were significantly different and negatively correlated between groups with MRI-T2*<20ms and ≥20ms, respectively. Flow-mediated dilatation (FMD) (6.08%±0.34% vs. 14.46%±1.12), aortic strain (7.79%±2.19% vs. 12.76%±4.19), ferritin levels were significantly different and negatively correlated between groups with MRI-T2*<20ms and ≥20ms, respectively. Higher ferritin, SDI12/16 were significant independent predictors of MR-T2*<20ms. SDI16>5.5, SDI12>4.3 predicted MRI-T2*<20ms with a sensitivity of 92%, specificity of 81% (AUC 0.85, P<.001), and sensitivity of 92%, specificity of 78% (AUC 0.83, P<.001), respectively. SDI12/16 calculated by 3D-echocardiography may be a promising predictors of cardiovascular iron load and, decreased LVEF-3D, FMD, and aortic strain might be good indicators of subclinical cardiovascular involvement of β-TM.