comparison of effects of different long-term iron-chelation regimens on myocardial and hepatic iron concentrations assessed with T2* magnetic resonance imaging in patients with beta-thalassemia major

Abstract

The aim of this study was to compare the effect of different long-term chelation regimens on heart and liver iron stores with the use of T2* magnetic resonance imaging (MRI) in patients with transfusion-dependent beta-thalassemia major. Sixty-four patients (28 men, 36 women; mean age, 26.49 +/- 5.8 years) were enrolled in the study. The 3 groups were based on the chelation therapy received. The first group (19 patients) received deferiprone (DFP) (75 mg/kg per day orally), the second group (23 patients) received deferoxamine (DFO) (30-50 mg/kg per day subcutaneously at least 5 times/week), and the third group (22 patients) received a combination of DFO (30-50 mg/kg per day, 2-3 days/week) and DFP (75 mg/kg per day, 7 days/week). MRI scans were acquired with an imager equipped with a 1.5 T magnet, and the data included myocardial and hepatic iron measurements obtained by means of T2*, and ventricular volumes and ejection fractions obtained with standard cardiovascular MRI techniques. The results revealed that the DFP and the combined groups had significantly less myocardial iron than the DFO group (mean myocardial T2*, 35.77 +/- 18.3 milliseconds and 38.05 +/- 15.3 milliseconds versus 23.77 +/- 13 milliseconds [P = .02, and P = .001], respectively). On the contrary, the DFP group had a significantly higher hepatic iron content than the DFO and combined groups (mean hepatic T2*, 3.29 +/- 2.5 milliseconds versus 8.16 +/- 8.4 milliseconds and 11.3 +/- 10.9 milliseconds [P = .014, and P = .003], respectively). No correlation was observed between myocardial T2* and hepatic T2* values (r = -0.043; P = .37). Myocardial T2* values were inversely correlated with age (r = -0.249; P = .024) and positively correlated with both left and right ventricular ejection fractions (r = 0.33 [P = .004], and r = 0.279 [P = .014], respectively). Finally, liver T2* was strongly and inversely correlated with serum ferritin concentration (r = -0.465; P = .001). In conclusion, combined chelation therapy seems to sum the beneficial effects of DFO and DFP with respect to hepatic and myocardial iron. Because myocardial iron is not related to measurements of serum ferritin or hepatic T2*, important decisions on clinical management relating to cardiac risk should not rely on these conventional parameters. Thus, the use of MRI for assessing myocardial iron should be adopted in the routine clinical management of patients with beta-thalassemia major.