Different patterns of myocardial iron distribution by whole-heart T2* magnetic resonance as risk markers for heart complications in thalassemia major.

Abstract

Background The multislice multiecho T2* cardiovascular magnetic resonance (CMR) technique allows to detect different patterns of myocardial iron overload (MIO). The aim of this cross-sectional study was to verify the association between cardiac complications (heart failure and arrhythmias), biventricular dysfunction and myocardial fibrosis with different patterns of MIO in thalassemia major (TM) patients. Methods We considered 812 TM patients enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) Network. The T2* value in all the 16 cardiac segments was evaluated. Results We identified 4 groups of patients: 138 with homogeneous MIO (all segments with T2* < 20 ms), 97 with heterogeneous MIO (some segments with T2* < 20 ms, others with T2* ≥ 20 ms) and significant global heart iron (global heart T2* < 20 ms), 238 with heterogeneous MIO and no significant global heart iron, and 339 with no MIO (all segments with T2* ≥ 20 ms). Compared to patients with no MIO, patients with homogeneous MIO were more likely to have cardiac complications (odds ratio—OR = 2.67), heart failure (OR = 2.54), LV dysfunction (OR = 5.59), and RV dysfunction (OR = 2.26); patients with heterogeneous MIO and significant global heart iron were more likely to have heart failure (OR = 2.38) and LV dysfunction (OR = 2.39). Conclusions Cardiac complications, heart failure and dysfunction were correlated with MIO distribution with an increasing risk from the TM patients with no MIO to those with homogeneous MIO. Using a segmental approach, early iron deposit or homogeneous MIO patterns can be characterized to better tailor chelation therapy.