Cardiac Iron Overload by MRI in Children With B-Thalassemia Major and its Correlation With Cardiac Function by Echocardiography

Abstract

Background: Serial echocardiography is strongly recommended in asymptomatic B-thalassemia major (TM) patients for early detection of subtle cardiac dysfunction. T2*magnetic resonance imaging (MRI) is a noninvasive measurement of myocardial iron burden. Yet, it is not always available in many centers. Our study aimed to evaluate the myocardial function in TM patients using different echocardiographic modalities and to correlate these findings with cardiac T2*MRI.

Patients and methods: This is a cross-sectional study that was carried out on 140 children with a mean age of 10.9±3.7 years. One hundred children with TM and 40 healthy children were matched for age and sex as a control group. Serum ferritin, serum iron, and iron-binding capacity were measured. Cardiac iron overload was assessed by T2*MRI and cardiac function was assessed by echocardiography. The local ethics committee approved the study.

Results: Among 100 children with TM, only 32% had cardiac iron overload of 8.525±5.45 detected by cardiac T2*MRI. Iron deposition correlated significantly with age. Markers of iron overload were significantly correlated with cardiac T2*MRI. There were significantly lower values of myocardial performance index, longitudinal strain, circumferential strain, area strain, and radial strain in TM patients compared with the controls (P<0.001). Only the myocardial performance index was correlated with T2*MRI.

Conclusions: This study confirms that some parameters measured by tissue Doppler imaging such as the myocardial performance index could be useful for the early detection of cardiac impairment in asymptomatic TM patients when cardiac MRI is lacking. Further studies on a large scale to identify other parameters with high sensitivity are recommended.