Cardiovascular Aspect of Beta-Thalassaemia

Abstract

Beta-thalassaemia major is a genetic blood disorder caused by the reduced synthesis of beta globin chain. The consequences of the resulting chronic anaemia are also common and include growth retardation, bone marrow expansion, extramedular hematopoiesis, splenomegaly, increased intestinal iron absorption, susceptibility to infections, and hypercoagulability. Transfusional iron overload can affect heart function by directly damaging tissue through iron deposition or via iron-mediated effects at other sites. Cardiac dysfunction is common in patients with thalassaemia and is the leading cause of mortality. The main cardiac abnormalities reported in patients with thalassaemia major (TM) and iron overload are left ventricular systolic and diastolic dysfunction, pulmonary hypertension, valvulopathies, arrhythmias and pericarditis. These cardiac abnormalities are a consequence of the general co-morbid conditions in thalassaemia but are closely related to concomitant endocrine deficiencies, hypercoagulability state and inflammatory milieu. Iron's toxicity within cells arises from its capacity to catalyse the production of reactive oxygen species that cause lipid peroxidation and organelle damage, which lead ultimately to cell death and fibrosis. With the introduction of new technologies such as cardiac magnetic resonance T2* , the early detection of cardiac iron overload and associated cardiac dysfunction is now possible, allowing time for reversal through iron chelation therapy.