cardio-pulmonary study on thalassemic children: relation to oxidant antioxidant balance and iron overload

ABSTRACT

beta-Thalassemia major is a common inherited disorder of hemoglobin synthesis in which iron overloading from regular blood transfusions results in organ dysfunction. Heart and liver dysfunction in thalassemia have been extensively-studied owing to their early effect on survival. Pulmonary dysfunction on the other hand is one of the least understood complications of beta-thalassemia major and represents one of the least studied complications in thalassemic patients. The aim of this study was to define the spirometric pattern and the possible causes of lung impairment in thalassemic patients. The study included 39 thalassemic patients [19 females and 20 males], with an age range from 8 to 16 years. Eighteen controls of matched age and sex were included in the study. A complete history was taken and a thorough physical examination was performed. In addition, the following investigations were done before blood trans fusion Hb, serum ferritin level, AST, ALT, erythrocytic thiobarbituric acid reactive substance [TBARS], super oxide dysmutase [SOD]'glutathione peroxidase [GPx], serum TBARS, SOD, glutathione [GSH], and vitamins A, C and E. Echocardiography was also done for all patients, the day before blood transfusion. Pulmonary function testing and arterial blood gases were performed prior to blood transfusion and 24 hours after blood transfusion. Restrictive lung pattern was predominant in beta-thalassemia major patients. This was manifested by a significantly lower FVC and a significantly higher FEV1/FVC in the studied patients than the controls. FVC carried significant negative correlation with ferritin. Patients had significantly higher values of TBARS and significantly lower values of serum SOD, GSH and the erythrocytic SOD and GPx and vitamins [E, A and C]. FVC carried significantly negative correlation with TBARS and significantly positive correlations with erythrocytic SOD, GPx, vitamins A and E. LVESD and LVEDD were significantly higher in the studied patients than the controls and both correlated negatively with FVC. EF, FS and PAT were significantly lower in the studied patients. EF and FAC correlated positively with FVC. L VESD and LVEDD correlated positively with ferritin and TBARS but negatively with GPx. restrictive lung disease was found to be the predominant pulmonary dysfunction in thalassemia major patients. This seems to be related to ferritin level, and might reflect the role of iron deposition and accumulation in the pathogenesis of pulmonary disease in thalassemia major. The restrictive pattern may also result from excess oxidative damage to the alveolar tissue or from cardiac changes that occurred in these patients. Accurate and early evaluation as well as follow up of pulmonary function and of bronchial reactivity is advisable for all patients with TM. Initial and follow up of cardiac performance in patients with thalassemia major is also important as it has a great impact on pulmonary functions in these patients. An ultimate goal in the management of thalassemia major is to design and try a combination of oral antioxidants and oral iron chelator to achieve good patient's compliance with the ease of administration for such patients who are living on repeated blood transfusion and hospital admission