Role of myocardial deformation imaging in transfusion-dependent thalassemia—Correlation with severity of myocardial siderosis

Objectives: To study clinical and echocardiographic parameters in Transfusion Dependent Thalassemia (TDT) patients, correlating them with T2*CMRI. To identify features of Speckle Tracking Echocardiography (STE) in those with severe TDT to prioritize patients in need of early T2*CMRI and aggressive chelation. Background: Hemosiderosis from life-long transfusions in TDT is amplified in Low- and Middle-Income Countries (LMIC) when access to resources may be scarce, delaying timely chelation. T2* imaging is the gold standard to non-invasively estimate myocardial iron and guide therapy. In resource constraint areas, we propose use of STE to prioritize those with severe disease to obtain early T2* CMRI. Methods: TDT patients (N = 25) who underwent clinical, echocardiographic, and CMRI evaluation were included, with recruitment of age matched controls. Echocardiographic indices of ventricular function and strain were correlated with T2*. Severe disease was defined as T2* < 10 ms. Differences among patients with severe disease and controls were analyzed in addition to differences between those with normal and abnormal T2*. Results: There was moderate (R −0.60, p = 0.002) inverse correlation between T2* and peak systolic global longitudinal strain (GLS) and regional basal strain (R −0.62, p < 0.001) indicating these parameters were lower in patients with severe disease when compared with controls and non-severe TDT group. GLS and most indices of regional strain were lower in patients with severe disease (T2* < 10 ms) when compared with the control group (p < 0.05). The Apex- base ratio reached significance (p = 0.02) in patients with abnormal T2*(<20 ms) when compared with normal T2*(<20 ms) in TDT positive patients. Conclusions: Early decrease in global and regional strain can serve as a useful tool to identify patients with severe TDT before reduction in ejection fraction. This study makes a case for utilizing STE as an adjunct or initial screen to T2* CMRI in LMIC to prioritize patients in need of T2*CMRI to facilitate aggressive iron chelation protocols.