ABSTRACT
BACKGROUND: Combination therapy with deferoxamine and oral deferiprone is superior to deferoxamine alone in removing cardiac iron and improving left ventricular ejection fraction (LVEF). The right ventricle (RV) is also affected by the toxic effects of iron and may cause additional cardiovascular perturbation. We assessed the effects of combination therapy on the RV in thalassaemia major (TM) using cardiovascular magnetic resonance (CMR). METHODS: We retrieved imaging data from 2 treatment trials and re-analyzed the data for the RV responses: Trial 1 was a randomized controlled trial (RCT) of 65 TM patients with mild-moderate cardiac siderosis receiving combination therapy or deferoxamine with placebo; Trial 2 was an open label longitudinal trial assessing combination therapy in 15 TM patients with severe iron loading. RESULTS: In the RCT, combination therapy with deferoxamine and deferiprone was superior to deferoxamine alone for improving RVEF (3.6 vs 0.7%, p = 0.02). The increase in RVEF was greater with lower baseline T2* 8-12 ms (4.7 vs 0.5%, p = 0.01) than with T2* 12-20 ms (2.2 vs 0.8%, p = 0.47). In patients with severe cardiac siderosis, substantial improvement in RVEF was seen with open-label combination therapy (10.5% ± 5.6%, p < 0.01). CONCLUSIONS: In the RCT of mild to moderate cardiac iron loading, combination treatment improved RV function significantly more than deferoxamine alone. Combination treatment also improved RV function in severe cardiac siderosis. Therefore adding deferiprone to deferoxamine has beneficial effects on both RV and LV function in TM patients with cardiac siderosis.
Subject(s)
Deferoxamine/therapeutic use , Hemosiderosis/drug therapy , Iron Chelating Agents/therapeutic use , Pyridones/therapeutic use , Siderophores/therapeutic use , Ventricular Dysfunction, Right/drug therapy , Ventricular Function, Right/drug effects , beta-Thalassemia/drug therapy , Adult , Analysis of Variance , Chi-Square Distribution , Deferiprone , Drug Therapy, Combination , Echocardiography, Doppler , Female , Hemosiderosis/diagnosis , Hemosiderosis/etiology , Hemosiderosis/physiopathology , Humans , Magnetic Resonance Imaging , Male , Randomized Controlled Trials as Topic , Recovery of Function , Retrospective Studies , Severity of Illness Index , Stroke Volume/drug effects , Therapeutics , Time Factors , Ventricular Dysfunction, Right/diagnosis , Ventricular Dysfunction, Right/etiology , Ventricular Dysfunction, Right/physiopathology , beta-Thalassemia/complications , beta-Thalassemia/diagnosis , beta-Thalassemia/physiopathologyABSTRACT
AIMS: Myocardial T2* cardiovascular magnetic resonance (CMR) provides a rapid and reproducible measure of cardiac iron loading and is being increasingly used worldwide for monitoring of transfusion-dependent thalassaemia patients. Although myocardial siderosis (T2* <20 ms) is associated with impaired left ventricular (LV) function, little is known of its relation with right ventricular (RV) function. The aim of this study was to investigate the relationship between cardiac T2* and RV function. METHODS AND RESULTS: A retrospective analysis of 319 patients with beta-thalassaemia major presenting for their first CMR scan was performed (45.1% male, mean age 25.6 years). In patients with normal myocardial T2* (>20 ms), the RV ejection fraction (EF) was within the normal range in 98% of patients. When myocardial T2* was <20 ms, there was a progressive and significant decline in RV EF. There was a linear relationship between RV and LV EF. CONCLUSION: Myocardial iron deposition is strongly associated with RV dysfunction, which mirrors the decrease in LV function seen with worsening cardiac iron loading. Right ventricular dysfunction may play a significant role in heart failure associated with myocardial siderosis.
Subject(s)
Cardiomyopathies/diagnosis , Ventricular Dysfunction, Right/diagnosis , beta-Thalassemia/complications , Adult , Cardiomyopathies/physiopathology , Female , Heart Failure/etiology , Heart Ventricles , Hemosiderosis/complications , Hemosiderosis/physiopathology , Humans , Iron/metabolism , Magnetic Resonance Angiography , Male , Retrospective Studies , Stroke Volume , Ventricular Dysfunction, Right/physiopathology , beta-Thalassemia/physiopathologyABSTRACT
Most deaths in beta-thalassemia major result from cardiac complications due to iron overload. Differential effects on myocardial siderosis may exist between different chelators. A randomized controlled trial was performed in 61 patients previously maintained on subcutaneous deferoxamine. The primary end point was the change in myocardial siderosis (myocardial T2(*)) over 1 year in patients maintained on subcutaneous deferoxamine or those switched to oral deferiprone monotherapy. The dose of deferiprone was 92 mg/kg/d and deferoxamine was 43 mg/kg for 5.7 d/wk. Compliance was 94% +/- 5.3% and 93% +/- 9.7% (P = .81), respectively. The improvement in myocardial T2(*) was significantly greater for deferiprone than deferoxamine (27% vs 13%; P = .023). Left ventricular ejection fraction increased significantly more in the deferiprone-treated group (3.1% vs 0.3% absolute units; P = .003). The changes in liver iron level (-0.93 mg/g dry weight vs -1.54 mg/g dry weight; P = .40) and serum ferritin level (-181 microg/L vs -466 microg/L; P = .16), respectively, were not significantly different between groups. The most frequent adverse events were transient gastrointestinal symptoms for deferiprone-treated patients and local reactions at the infusion site for deferoxamine. There were no episodes of agranulocytosis. Deferiprone monotherapy was significantly more effective than deferoxamine over 1 year in improving asymptomatic myocardial siderosis in beta-thalassemia major.