Cardiac iron and cardiac disease in males and females with transfusion-dependent thalassemia major: a T2* MRI study

Background It has been repeatedly reported that female patients with thalassemia major survive longer than males and that the difference is due to a lower rate of cardiac disease in females. Design and Methods We compared the cardiac iron load as measured by T2* magnetic resonance imaging in 776 patients (370 males) examined at the National Research Council as part of an Italian cooperative study. We also established normal left ventricular ejection fraction values for our population. Results The prevalence of cardiac disease was higher in males than in females (105 males versus 69 females; P<0.0001). Cardiac T2* was significantly lower in patients with heart dysfunction (P<0.0001), but no difference was observed according to sex. Twenty males and five females had a history of cardiac arrhythmias. Their cardiac T2* was not significantly lower than that of patients without arrhythmias (24 ms versus 26 ms; P=0.381), nor was there a difference between sexes. Liver T2* was significantly lower in males and females with heart dysfunction compared to those without. Ferritin levels were higher in patients of both sexes with heart dysfunction without significant differences between males and females. Conclusions Males and females are at the same risk of accumulating iron in their hearts, but females tolerate iron toxicity better, possibly as an effect of reduced sensitivity to chronic oxidative stress.