Top Things to Know: Cardiovascular Function and Treatment in Beta-Thalassemia Major
Published: June 17, 2013
- Beta-thalassemia major (TM) is a genetic condition where the beta globin chain of hemoglobin A (Hb) is severely reduced or absent. Erythropoiesis is ineffective, resulting in profound, life-threatening anemia from about 1-2 years of age.
- TM is most common in areas of the world where the population is exposed to malaria (Asia, Middle-East, and Mediterranean Europe). The frequent hemoglobin genetic mutations in these populations that infer protection against malaria also result in mutations for TM.
- Lifetime blood transfusions are required to prolong life, but total body iron increases, resulting in iron overload.
- Heart failure (HF) is the most common cause of death in TM and primarily results from cardiac iron accumulation.
- This consensus statement addresses the diagnosis and treatment of cardiac dysfunction in beta-thalassemia major, including how to measure cardiac iron and function, to identify and treat patients at high risk in order to prevent heart failure, and to diagnose and treat HF.
- Treating HF in TM now includes iron chelation therapy. Agents discussed include deferoxamine, deferiprone, and deferasirox.
- The use of chelation therapies for TM has moved the typical age of death by primarily cardiac causes from 10 years in the 1970’s to a median age of 35 years.
- “Iron cardiomyopathy is the most common and feared complication of TM, but as it is caused by iron toxicity, it is reversible.”
- Acute and chronic treatment of HF in TM is different for several reasons:
- the patients are younger,
- because this HF is a result of a toxic cardiomyopathy, the therapeutic goal is removal of the iron rather than treating the myocardial performance, and
- additional co-morbidities may exist that require identification and specific treatment.
- Many questions remain unanswered. There is a lack of high-quality studies in large populations, but trials are under way looking at new chelators and chelator combinations. Non-invasive ways to measure iron and strategies to prevent cardiac iron loading are other directions for research.
Citation
Pennell DJ, et al; on behalf of the American Heart Association Committee on Heart Failure and Transplantation of the Council on Clinical Cardiology and Council on Cardiovascular Radiology and Imaging. Cardiovascular Function and treatment in β-thalassemia major: a consensus statement from the American Heart Association. Circulation, 10.1161/CIR.0b013e31821c7c64.
http://circ.ahajournals.org/lookup/doi/10.1161/CIR.0b013e31829b2be6