Improvement of Cardiac Function and Cardiac Volumes in Patients Treated with Deferasirox

The iron chelation therapy in thalassemia major (TM) patients has been demonstrated to reduce cardiac morbidity and mortality. Deferoxamine (DFO) significantly improved survival but its use has several limitations due to reduced compliance. The once-daily oral chelator deferasirox (DFX) has been shown to remove iron from the liver and from the heart, with improved compliance. The efficacy of DFX in removing cardiac iron has been shown and significant improvements in myocardial T2* in patients with b-thalassemia with T2* levels < 20 ms have been demonstrated. The introduction in the clinical practice of the T2* Cardiac Magnetic Resonance (CMR) evaluation permitted a rapid, direct and highly reproducible method to assess myocardial and hepatic iron overload; moreover this technique allows to evaluate cardiac morphology and function. We evaluated the removal of cardiac iron and the cardiac function parameters in TM patients treated with DFX, undergoing CMR,followed at Hereditary Anemia Centre, Department of Internal Medicine in Milan.

Forthy-one TM patients (22 females, 19 males, mean age 32 ± 6 yrs), treated with DFX, followed in a single centre, underwent a CMR, performed at baseline (T₀), after a variable period of exposure to DFX (median: 12 months, range 4–48 months) and then after at least 6 months of treatment (T₁) (median 12 months, range 6–19 months). CMR was performed at Cardiology and CMR Department “A. De Gasperis” at Niguarda Ca' Granda Hospital in Milan, using a 1.5 Tesla MR scanner (Avanto Siemens, Erlangen). The signal intensity of this region was measured for each image with the use of commercial software (CMRtools, Cardiovascular Imaging Solutions, London, UK). All T2* analyses were performed blinded to patient details. Ventricular volumes were analyzed with the same software and stroke volume and ejection fraction calculated from end diastolic and end systolic ventricular volumes. Patients were divided in two groups: group A (28 patients) with baseline T2* values > 20 ms and group B (12 patients) with baseline T2* between 10 and 20 ms.

In the overall population, the mean deferasirox dose was 26±7 mg/kg/day; dose adjustment was based on iron intake and on liver and cardiac iron overload at CMR. Despite different durations of deferasirox exposure and different levels of myocardial iron overload, an average improvement of myocardial T2* from 27.4 ms to 29.8 ms was observed at T₁ (P=0.004). A significant improvement in LVEF from 63.6 % to 66.5 % (P=0.013), indicative of improved cardiac function, was also observed. Similarly, both end-systolic and end-diastolic ventricular volume assessments (EDV, EDVI, ESV, ESVI) showed significant improvement at T₁. No difference in median serum ferritin levels were found between group A and B. Myocardial T2* increased in both groups with DFX treatment, with a significant improvement observed in Group B patients (T2* at T₀ was 15.7 ± 2.7 ms and at T₁ 19.6 ± 3.8 ms, P=0.003) (Table 1). LVEF significantly increased in both groups, from 65.7% to 68.0 % in Group A (P=0.01) and from 59.7% to 64.3% in Group B (P=0.04) (Table 1). In Group A, improvements in EDV, ESV and ESVI were also significant with deferasirox treatment; in Group B significant improvements were observed in ESV and ESVI (Table 1).

These data confirm the effects of iron chelation with deferasirox in removing cardiac iron in beta TM patients with mild-to-moderate myocardial iron overload and preventing accumulation of myocardial iron in patients with normal baseline cardiac iron levels. Interestingly, improvements in cardiac function were observed both in patients with and without myocardial iron overload at baseline, however it was more significant in patients with normal T2* at baseline.

No relevant conflicts of interest to declare.