Prospective Assessment of Cardiac Iron Deposition, Morphology, and Function by Magnetic Resonance Imaging in Non-Transfusion-Dependent and Neo-Transfusion-Dependent Thalassemia

<b>Objectives</b>: We compared changes in hepatic and cardiac iron levels, left ventricular (LV) and right ventricular (RV) dimensions and function, and bi-atrial areas, all assessed through magnetic resonance imaging (MRI), between patients with non-transfusion-dependent thalassemia (NTDT) and those with neo-transfusion-dependent thalassemia (neo-TDT) over an 18-month follow-up period. <b>Methods</b>: We included 32 NTDT patients (42.78 ± 12.62 years, 53.1% females) and 58 neo-TDT (>4 transfusions per year) patients (44.08 ± 14.13 years, 46.6% females), consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia project. Iron overload was quantified by T2* technique, biventricular function and atrial areas by cine images. Macroscopic myocardial fibrosis was detected by the late gadolinium enhancement technique. <b>Results</b>: Changes in cardiac and hepatic iron levels, in biventricular ejection fractions, in LV mass index, and bi-atrial areas were comparable between the two groups. A trend of worsening biventricular dimensions was observed in the NTDT group, while the neo-TDT group showed an improvement (decrease) in biventricular size (LV stroke volume index: <i>p</i> = 0.036; LV cardiac index: <i>p</i> = 0.031; RV end-diastolic volume index: <i>p</i> = 0.034; RV stroke volume index: <i>p</i> = 0.033). The inter-group comparison showed significant differences in the changes of biventricular end-diastolic volume indexes (LV: <i>p</i> = 0.011 and RV: <i>p</i> = 0.034) and stroke volume indexes (LV: <i>p</i> = 0.036 and RV: <i>p</i> = 0.033) and in the cardiac index (<i>p</i> < 0.0001). At both MRI scans, the frequency of replacement myocardial fibrosis was comparable between the two groups. <b>Conclusions</b>: Our 18-month longitudinal data revealed distinct patterns of cardiac remodeling in NTDT and neo-TDT patients. The progressive ventricular dilation observed in NTDT patients highlights the need for careful MRI monitoring and potential interventions to address the long-term cardiac consequences of anemia.