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.

Keywords: Cardiac complications; Cardiovascular magnetic resonance; Myocardial iron overload; Thalassemia major.