Beta-Thalassemia Major and Myocardial Iron Overload: A Longitudinal Study with Magnetic Resonance Imaging.

Background: Patients with β-thalassemia major depend on lifelong transfusion, resulting in tissue iron overload. This longitudinal retrospective observational study aims to assess myocardial and liver iron overload using magnetic resonance imaging (MRI) and investigate the lag between myocardial and liver iron unloading in β-thalassemia patients undergoing chelation therapy.

Methods: Beta-thalassemia major patients with at least two MRI studies between 2016 and 2020 were enrolled. Myocardial and liver iron overload were defined as T2 ^∗ less than 20 and 2.1, respectively. Outcomes included mortality, myocardial and liver T2 ^∗ changes, and systolic dysfunction assessed by cardiac MRI.

Results: Fifty-five patients with a mean age of 24.62 ± 7.94 years, a mean follow-up duration of 24.3 ± 12.9 months, and a mean ferritin level of 1475.75 ± 771.12 ng/mL were enrolled. All of the abovementioned patients only took deferoxamine as the iron-chelating medication. Mortality occurred in three patients (5.5%) during follow-up. Liver T2 ^∗ significantly increased (p value <0.05), while myocardial T2 ^∗ showed a nonsignificant increase. Iron unloading of the myocardium was not significantly different from that of the liver and did not result in a significant lag (56% vs. 44%; p value = 0.419). Baseline myocardial T2 ^∗ correlated with extramedullary hematopoiesis, weekly number of deferoxamine injections (p value <0.01), timing between the transfusions, and serum ferritin (p value <0.05).

Conclusion: Liver T2 ^∗ reduced during deferoxamine chelation therapy, while myocardial T2 ^∗ remained unchanged. No significant lag was observed between myocardial and liver iron unloading. Further studies are required to elucidate these findings.