The effect of subcutaneous deferoxamine on the cardiac profile of thalassemia major: A five-year study
In our study, a moderate to intensive course of s.c. DFO at the daily dose of 20 mg/kg of body weight was maintained over a five-year period. Reduction in the incidence of cardiac arrhythmias has been demonstrated in younger patients begun on therapy before the age of 13 years. Arrhythmia in the more heavily iron-burdened subjects begun late in adolescence was not as dramatically altered. Although arrhythmias were reversed in some of these older adolescents, the majority who had arrhythmias at the start of chelation showed progressive cardiac deterioration, developed congestive heart failure, and died at a mean age of 19.5 years. Demise was predicted by an abnormal echographic ejection fraction usually preceding death by twelve months or less. It is still too soon to comment on the effects of DFO on myocardial function of those subjects begun on s.c. DFO in their younger years, since they have yet to complete the second decade of life. However, the success demonstrated in the diminution of cardiac arrhythmias with the stabilization of body iron loading and the reduction in the rate of iron accumulation in the regularly transfused thalassemic suggests that progressive myocardial toxicity may also be altered. Long-term daily use of prolonged s.c. DFO infusions are an important factor in the improved prognosis of children with thalassemia major. Our current studies are directed to investigating the efficacy of increased s.c. DFO dosage since the ideal s.c. dosage remains in question as is the mechanism of its actions and patterns of stool and urinary iron excretion.