Longitudinal strain in beta thalassemia major and its relation to the extent of myocardial iron overload in cardiovascular magnetic resonance

Abstract

Background: Iron overload is a common problem in beta-thalassemia major. Finding a reliable and available modality to determine the presence of iron overload in the initial stages might decrease the risk of cardiomyopathy. We sought a reliable echocardiographic index to assess the extent of iron overload. Methods: This cross-sectional study was conducted on patients with beta-thalassemia major from June 2016 to May 2017. All the patients underwent T2* magnetic resonance imaging, conventional echocardiography, tissue Doppler study, and strain imaging for the measurement of ventricular systolic function indices including the left ventricular global longitudinal strain (LVGLS). The echocardiographic findings were compared between those with myocardial iron overload (T2* ≤20 ms) and those without it (T2* >20 ms) and in the second phase between those with nonsevere overload (20 ms >T2* >10 ms) and those with severe overload (T2* ≤10 ms). Results: Forty-four patients, comprising 23 (52.35%) males and 21 (47.7%) females, were enrolled. All the patients were receiving chelating drugs. The LVGLS showed a significant difference between those with myocardial iron overload and those without it (P = 0.012). Accordingly, a cutoff value of −17.5 for the LVGLS had 100% specificity and 43.8% sensitivity. Concerning the distinction between nonsevere and severe iron overload states, the average LVGLS (P