Abnormal diastolic function and Global longitudinal strain in patients with Thalassemia Major on long term chelation therapy

Cardiac complications are the major cause of mortality in patients with Thalassemia major (TM). Cardiac T2* MRI is currently the gold standard for assessing myocardial iron concentration. The aim of our study was to assess whether any echocardiographic parameter would correlate with these findings in patients well established on chelation therapy. This was a prospective study on patients with TM who are regularly followed in our clinic. Patients had a cardiac MRI and echocardiogram within 2 months of each other. Echo parameters included global longitudinal strain and diastolic function. We also compared these findings with those from a cohort of thalassemia intermedia (TI) and normal controls. A total of 84 patients (mean age 26.3 ± 6.1 years, 42.8% male) with TM were enrolled. All had normal left ventricular ejection fraction and only 8 patients had MRI T2* < 10. As compared to 17 patients with TI and 53 controls, these patients had significantly higher E/E’ and lower pulmonary vein s/dd ratio suggesting early diastolic dysfunction. 28 patients fulfilled criteria for diastolic dysfunction even in the presence of normal MRI T2*. Global longitudinal strain (GLS) was significantly lower in the TM group as compared to the TI and controls. We found no correlation between any of the echo findings and the MRI T2*in TM patients. In patients with thalassemia and MRI T2* > 20 ms features of diastolic dysfunction persist even in the presence of normal LV function and normal GLS. This suggests that diastolic function remains abnormal even when myocardial iron concentrations are normal and follow up therefore is essential.