Lungs in thalassaemia major patients receiving regular transfusion

Abstract

Progressive tissue iron deposition from multiple blood transfusions is common in beta-thalassaemia and pulmonary iron deposition may result in parenchymal damage. The objectives of this study were to: 1) determine the predominant pulmonary dysfunction in patients with thalassaemia major; and 2) demonstrate that parenchymal disease, if present, is at the level of the alveolocapillary membrane.Fourteen thalassaemia major patients (13 nonsmokers) receiving regular blood transfusion and without any history of chronic respiratory disease were recruited. Pulmonary function tests and echocardiography were performed before the scheduled transfusions. Three patients with the most restricted lung function were selected for high resolution computerized tomography (CT) of the lungs.One patient had an obstructive pattern with a forced expiratory volume in one second as percentage of forced vital capacity (FEV1/FVC) of 71%. Four patients demonstrated a restrictive pattern, as defined by total lung capacity (TLC) less than 80% predicted with normal FEV1/FVC%. Twelve patients had pulmonary transfer factors for carbon monoxide (TL,CO) below 80% pred, even after correction for the anaemia, indicating parenchymal disease. Eight of these 12 patients had alveolocapillary membrane defect, as demonstrated by a gas transfer factor of the pulmonary membrane (Tm) less than 80% pred. Mean resting arterial oxygen saturation was 95±2 (range 92-98) %. Eleven patients had oxygen desaturation of 5% or more during exercise on a bicycle ergometer, consistent with interstitial lung disease. There was no clinical or echocardiographic evidence of heart failure. Percentage predicted TLC was inversely correlated with age (r=-0.547; p=0.043). Both percentage predicted TLC and TL,CO were not correlated with iron burden or desferoxamine ratio. High resolution CT in the three selected patients showed no evidence of pulmonary fibrosis. We conclude that thalassaemia major patients have a predominant restrictive lung dysfunction with pulmonary parenchymal disease and alveolocapillary membrane block. The restrictive and interstitial lung disease could not be accounted for by iron loading or pulmonary fibrosis in our patients.

Exercise performance in thalassemia major: Correlation with cardiac iron burden

“…We found that patients with TM have decreased aerobic capacity (decreased V O2 max), in agreement with the literature [4][5][6][7][8][9][10][11][12][13]. Only one article did not find decreased exercise capacity in TM patients.…”

“…Exercise capacity is reduced in patients with TM [4][5][6][7][8][9][10][11][12][13] and most studies have attributed these findings to a combination of anemia and iron-mediated cardiotoxicity [4,6,7,10]. Cardiopulmonary exercise function testing has been proposed as a noninvasive test to detect early cardiac dysfunction [7]; however, the ability to detect cardiac iron with exercise testing is largely unvalidated.…”

Comparison of pulmonary functions of thalassemic and of healthy children

“…Among the thalassemic subjects, restrictive lung function abnormality was the most common (42/63) observation documented in this study. Our findings are consistent with those of Carnelli et al, 1 Factor et al, 2 Tai et al, 5 Luyt et al, 6 and Filosa et al 7 What is unique to our study is that it was performed exclusively in children, while those studies mentioned earlier were all performed in both children and adults, with a considerably older mean age. Therefore, our study shows that lung dysfunction in thalassemic patients has occurred since childhood.…”

“…Some studies find a significant inverse correlation between total lung capacity and iron burden 1-3 as well as between total lung capacity and age. 1,2 Others find that neither age 4 nor iron load 4,5,8 correlated with pulmonary function. To our knowledge, no data on this issue is available in Indonesia.…”

“…There was no correlation between percentage from predicted forced vital capacity and serum ferritin levels, whether in male (r=0.191; P=0.967) or female (r =-0.076, P=0.695) thalassemic subjects. Keywords: pulmonary function, thalassemia, spirometry, serum ferritin level, restrictive lung dysfunction T halassemia refers to a heterogeneous group of heritable hypochromic anemias of various degrees of severity; [1][2][3][4][5][6][7][8][9] it is considered to be the most prevalent genetic disorder in the world. 3 Transfusions of 15-20 ml/kg of packed cells are usually required every 4-5 weeks.…”