Early identification of cardiac iron overload in children with transfusion dependent thalassemia using two-dimensional speckle-tracking echocardiography and its comparison with cardiac MRI T2*: a diagnostic accuracy study

Cardiac iron overload (CIO) remains the leading cause of morbidity and mortality in patients with transfusion dependent thalassemia (TDT), hence its early recognition is crucial. For this, cardiac MRI T2*(CMRI T2*) is the gold standard but it has limited accessibility. Two-dimensional speckle-tracking echocardiography (2DSTE) has emerged as a sensitive modality, to evaluate 2DSTE in detecting early cardiac dysfunction in TDT patients against CMRI T2*. In this study, 90 children with TDT and 47 controls underwent conventional transthoracic echocardiography (TTE) and 2DSTE. CMRI T2* was performed in patients older than eight years. TTE parameters and global longitudinal strain (GLS; 2 C, 3 C, 4 C, and average) were analysed and compared between patients and controls and with CMRI T2*. The mean age of patients was 11 years and 68.9% were male and that of controls was 10.06 years and 53.2% were male. Except E/A and E/e’, TTE parameters like LVEF did not differ significantly between patients and controls. The GLS also was higher though not significant statistically. Sixty-three patients underwent CMRI, 23 had T2* values > 20 ms and were grouped as ‘no cardiac loading’ and the rest as ‘with cardiac loading’. Conventional TTE parameters did not differ significantly between groups but GLS was significantly higher (p value-<0.001). ROC analysis demonstrated that an average GLS cut-off <–20.01 predicted CIO with 70% sensitivity, 87% specificity with PPV of 90.3%, and NPV of 62.5%. 2DSTE may be an useful adjunct for early detection of CIO and may complement cardiac T2* MRI in resource limited settings.