Comparison of biventricular dimensions and function between pediatric sickle-cell disease and thalassemia major patients without cardiac iron

Patients with chronic anemia develop compensatory ventricular dilation, even when maintained on chronic transfusion regimens. It is important to characterize these effects to interpret pathological changes in cardiac dimensions and function introduced by iron overload and sickle cell vasculopathy. Our primary goal was to compare biventricular dimensions and function assessed by cardiovascular magnetic resonance (CMR) in pediatric, chronically-transfused sickle-cell disease (SCD) and thalassemia major (TM) patients who had normal cardiac iron levels. Moreover, we explored systematic sex differences in ventricular dimensions in both populations. We identified 261 studies suitable for analysis from 64 patients with SCD (34 females) and 49 patients with TM (20 females). All demographic and CMR parameters were inversely weighted by the number of exams. In both populations, males had larger left and right ventricular dimensions than females, with a more marked effect observed in patients with SCD. Compared to patients with TM, patients with SCD showed significantly greater biventricular dilation and left ventricular hypertrophy. This difference could not be explained by different hemoglobin levels, cardiac iron overload, and systolic blood pressure. The left ventricular (LV) ejection fraction (EF) for the males and the right ventricular (RV) EF for both the sexes were comparable between SCD and TM groups, while females with SCD had significantly lower LV EF than females with TM. Our results represent important baseline findings that place changes introduced by iron overload as well as systemic and pulmonary vasculopathy in proper context.