Pulmonary function abnormalities in thalassemia major and the role of iron overload

Pulmonary function in patients with transfusion-dependent thalassemia and its associations with iron overload

In patients with transfusion-dependent thalassemia (TDT), pulmonary function impairment has been reported but data are conflicting. Moreover, it remains unclear whether pulmonary dysfunction is associated with iron overload. This study aimed to evaluate the pulmonary function in patients with TDT and to investigate the associations between pulmonary dysfunction and iron overload. It was a retrospective observational study. 101 patients with TDT were recruited for lung function tests. The most recent ferritin levels (pmol/L) and the magnetic resonance imaging (MRI) measurements of the myocardial and liver iron status, as measured by heart and liver T2* relaxation time (millisecond, ms) respectively, were retrieved from the computerized medical records. Only data within 12 months from the lung function measurement were included in the analysis. The serum ferritin, and the cardiac and liver T2* relaxation time were the surrogate indexes of body iron content. The threshold of abnormality in lung function was defined as under 80% of the predicted value. 101 subjects were recruited with a mean age of 25.1 years (standard deviation (SD) 7.9 years). Thirty-eight (38%) and five (5%) demonstrated restrictive and obstructive lung function deficits, respectively. A weak correlation of FVC %Predicted and TLC %Predicted with MRI myocardial T2* relaxation time (rho = 0.32, p = 0.03 and rho = 0.33, p = 0.03 respectively) was observed. By logistic regression, MRI cardiac T2* relaxation time was negatively associated with restrictive lung function deficit (B - 0.06; SE 0.03; Odds ratio 0.94; 95% confidence interval (CI) 0.89-0.99; p = 0.023) after adjusting for age, sex and body mass index. Restrictive pulmonary function deficit was commonly observed in patients with TDT, and the severity potentially correlates with myocardial iron content. Monitoring of lung function in this group of patients, particularly for those with iron overload, is important.

Association of serum ferritin and lung function in tobacco-naïve postmenopausal women: Analysis of population-based nationally representative data

INTRODUCTION

Ferritin regulates iron homeostasis, and is involved in the inflammation in the lung, especially in smokers; however, its associations on pulmonary function in nonsmokers remain unclear.

OBJECTIVES

The present study aimed to evaluate the association between serum ferritin and lung function in a tobacco-naïve postmenopausal women.

METHODS

In this study, 25 534 individuals were enrolled, among who 5338 tobacco-naïve individuals were identified; of those, 342 men and 2879 women (742 pre- and 2137 postmenopausal) with data of serum ferritin, lung function and covariates were included. To evaluate the association of ferritin and lung function, multivariable-adjusted linear regression analyses was used including the factors of predicted value of forced expiratory volume in 1 second (FEV1 %) and forced vital capacity (FVC%). Logistic regression analyses were used to measure the relationship between ferritin and restrictive and obstructive lung disease.

RESULTS

In premenopausal women, FEV1 %/FVC was weakly but positively associated with serum ferritin, and after adjusting for covariates, the association was without statistical significance. No significant association between ferritin and obstructive lung disease was observed. In postmenopausal women, predicted FVC% was negatively associated with serum ferritin, and ferritin was dose-dependently related with risk for restrictive lung disease. The odds ratio for restrictive lung disease in postmenopausal women was 2.285 at T3 and 1.560 at T2 relative to that at T1.

CONCLUSIONS

High serum ferritin level was significantly associated with lower FVC% and increased risk of restrictive lung disease in tobacco-naïve postmenopausal women. Further study is needed to determine the mechanism underlying the current findings.

The improvement of pulmonary artery pressure after bosentan therapy in patients with β-thalassemia and Doppler-defined pulmonary arterial hypertension

Introduction

Pulmonary arterial hypertension (PAH) is relatively prevalent in patients with thalassemia. PAH treatment is necessary as the prevalence of Doppler-estimated PAH and the resultant mortality is high in such patients.

Materials and methods

This study aimed at evaluating the effect of bosentan therapy on patients with thalassemia suspected of PAH. Based on pulsed Doppler echocardiography, all the cases were suspected of severe PAH. Consequently, bosentan was initiated at a dose of 62.5 mg twice a day for 4 weeks, which was increased to 62.5–125 mg twice a day, if no adverse side effects were observed.

Results

The results of this study showed that pulmonary artery pressure (PAP) decreased after the administration of bosentan in three cases, from 160 to 120, 110 to 65, and 60 to 25 mmHg; in other words, the PAP reduced in the mentioned cases by 25%, 36.4%, and 58.4%, respectively.

Conclusion

In this study, PAP improved after bosentan therapy in patients with β-thalassemia suspected of PAH; however, further studies are required to confirm the findings.

Pulmonary dysfunction in thalassaemia major: is there any relationship with body iron stores?

Although pulmonary function abnormalities in thalassaemia major (TM) were described in 1980, the pathogenetic mechanism is not clear and data are contradictory, probably because of study heterogeneity and the multifactorial nature of the pathogenesis. We retrospectively analysed 73 adult TM patients to evaluate the prevalence of pulmonary dysfunction in adult TM and investigate relationships with iron load. All patients underwent body plethysmography and carbon monoxide diffusion (DLCO) was assessed in 63, in addition to blood tests, echocardiogram and T2* myocardial and liver magnetic resonance imaging. Restrictive lung disease was present in 26 (35·6%) patients. Serum ferritin levels were higher in patients with restrictive pattern (1526 μg/l vs. 975 μg/l, P = 0·05). Restrictive lung disease did not correlate with cardiac or liver iron overload. However, considering only patients with serum ferritin >2500 μg/l, those with restrictive pattern also had heart (T2* 14·28 ± 9·99 ms vs. 31·59 ± 7·43 ms) and liver iron overload (LIC 16·02 ± 8·44 mg vs. 5·02 ± 2·69 mg Fe/g dry weight) compared to those without restrictive pattern. Twenty-five patients (39·7%) had decreased DLCO. No correlation was observed with iron parameters. In our data restrictive pattern was predominant; we observed a relationship with serum ferritin levels suggesting that iron, particularly its chronic effect, could play a role in the pathogenesis of pulmonary disease.

Pulmonary hypertension associated with thalassemia syndromes

Chronic hemolytic anemia has increasingly been identified as an important risk factor for the development of pulmonary hypertension (PH). Within the thalassemia syndromes, there are multiple mechanisms, both distinct and overlapping, by which PH develops and that differ among β-thalassemia major or intermedia patients. PH in β-thalassemia major correlates with the severity of hemolysis, yet in patients whose disease is well treated with chronic transfusion therapy, the development of PH can be related to cardiac dysfunction and the subsequent toxic effects of iron overload rather than hemolysis. β-Thalassemia intermedia, on the other hand, has a higher incidence of PH owing to the low level of hemolysis that exists over years without the requirement for frequent transfusions, while splenectomy is shown to play an important role in both types. Standard therapies such as chronic transfusion have been shown to mitigate PH, and appropriate chelation therapy can avoid the toxic effects of iron overload, yet is not indicated in many patients. Limited evidence exists for the use of pulmonary vasodilators or other therapies, such as l-carnitine, to treat PH associated with thalassemia. Here, we review the most recent findings regarding the pathogenic mechanisms, epidemiology, presentation, diagnosis, and treatment of PH in thalassemia syndromes.

Pulmonary Functions in Children With Thalassemia Major

BACKGROUND

Thalassemia major (TM) is a chronic disease requiring regular transfusions that may result in generalized iron loading, such as in the heart, the liver, endocrine organs, and the lungs. We aimed to determine pulmonary function abnormalities in children with TM in our center.

PATIENTS AND METHODS

In this study, pulmonary function tests (PFTs) of 49 patients with TM who received regular blood transfusion and had no history of chronic respiratory disease were evaluated. The relationship between PFTs and the age, the body surface area, pretransfusional hemoglobin, and serum ferritin was evaluated.

RESULTS

Among the β-TM patients included in this study, 61% were male and 39% were female, with a mean age of 10.8±3 years (range, 5 to 17 y). The patients' mean level of ferritin was 3873±2011 ng/dL (range, 676 to 9476 ng/dL). A reduced forced vital capacity (FVC) was found in 33 patients (67%). A reduced forced expiratory volume in 1 second (FEV1) was found in 15 patients (30%). A forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) ratio of >80% was found in all patients. The peak expiratory flow (PEF) was decreased in 23 patients (46.9%). The forced mid-expiratory flow between 25% and 75% of the exhaled vital capacity (MEF25%-75%) was decreased in 5 patients (10%). FVC and FEV1 values in patients with a high ferritin level (>2500 ng/dL) were decreased compared with patients with a low ferritin level (<2500 ng/dL) (P=0.04, 0.03). FVC, FEV1, and PEF parameters were negatively correlated with the age and the body surface area. Age was a predictor of FVC (β=-0.450, P<0.001), FEV1 (β=-0.419, P<0.001), and PEF (β=-0.505, P<0.001), and hemoglobin was a predictor of FEV1/FVC (β=0.366, P=0.01) and MEF25%-75% (β=0.323, P=0.003).

CONCLUSIONS

Our results concluded that the respiratory system should be evaluated by PFTs even in asymptomatic patients with high serum ferritin levels during the adolescent period annually to prevent the squeal of pulmonary disease in TM. Patients who have abnormal PFTs should be reevaluated for compliance with chelation therapy and the transfusion program.

Restrictive pulmonary dysfunction and its predictors in young patients with β-thalassaemia major

BACKGROUND

Pulmonary dysfunction represents one of the most undervalued and less recognized complications in patients with β-thalassaemia.

OBJECTIVES

The aim of this study was to assess the pattern of pulmonary dysfunction and consequently to investigate possible associated factors that might contribute to lung impairment in young patients with β-thalassaemia major.

METHODS

Fifty-two children and young adults (mean age: 21.33 ± 6.24 years) with β-thalassaemia major on conventional treatment (transfusions and iron chelation therapy) were included in the study. A complete computerized pulmonary function testing (PFT) system for recording pulmonary diffusion capacity and simultaneous determination of alveolar volume and pulmonary volumes was equipped.

RESULTS

Results showed that 20 patients (38.46%) had restrictive pulmonary pattern that was preferentially observed in older and shorter patients. Serum ferritin levels were higher in the restrictive group (2,096 ± 1,831 ng/dl) compared to patients with normal pulmonary function (1,354 ± 942 ng/dl) (P = 0.066). Diffusional impairment characterized by significantly lower DLCO*% values, was observed in the restrictive group (P = 0.004), implicating the 62.5% of the population studied. Paired linear correlations showed that age was negatively correlated to DLCO*% (r = -0.548, P < 0.001) and SaO(2) % (r = -0.789, P < 0.001) and with most of the pulmonary functional parameters that determine a restrictive. Multivariate regression analysis identified age as the major predictor for restrictive pulmonopathy followed by serum ferritin levels.

CONCLUSIONS

Our study shows that pulmonary impairment is shown in a great proportion even among asymptomatic young thalassaemic patients, thus, regular screening of pulmonary function should be adopted in the routine clinical follow up of these patients.

Pulmonary function test in transfusion-dependent β-thalassemia major patients: a pilot study

Lung involvement is one of known complications of thalassemia. The aim of this study was to determine predominant type of pulmonary dysfunction and its relationship to iron overload in β-thalassemia children. Fifty thalassemia major children with treatment of regular blood transfusion and desferrioxamine participated in the study. Thirty-three boys and 17 girls (median age 12.5 years) with β-thalassemia enrolled in the study. Other information including body mass index, hematocrit, and the number of years of blood transfusion were recorded. Serum ferritin level and hematocrit were 3346 ± 1667 mg/dL and 27.7 ± 2, respectively. Pulmonary function tests were performed in all subjects for detecting pulmonary dysfunction. Thirty-five patients (70%) with thalassemia had abnormal result of spirometry. Obstructive airway disease based on reduced forced expiratory volume in 1 second (FEV(1)) and FEV(1)/forced vital capacity (FVC) ratio <80% was detected in 4 patients (8%). Six patients (12%) showed restrictive pattern, as defined by a reduction FVC <80% and FEV(1)/FVC ratio ≥80%. In this study, small airway involvement based on presence of forced expiratory flow (FEF(25%-75%)) <60%, FEV(1)/FVC ratio >70%, and FVC >80% was detected in 25 subjects (50%). Decreased values of peak expiratory flow rate (PEF) were detected in 23 (46%) and low FEV(1) in 10 (20%) subjects. There was no significant correlation between abnormal pulmonary function test and serum ferritin level in children with thalassemia. This study showed small airway disease was predominant abnormality in thalassemia patients, although additional larger studies are needed to evaluate underlying mechanisms and validate these findings.

Frequency of pulmonary hypertension in asymptomatic β-thalassemia major patients and the role of physiological parameters in evaluation

In this study, the authors aimed to evaluate the frequency of pulmonary hypertension (PHT) in asymptomatic thalassemia major (TM) patients, and to investigate the impact of pulmonary function test (PFT) and CO diffusion results on the evaluation of pulmonary hypertension. Data from 50 asymptomatic patients with TM over age 10 were evaluated. Pulmonary hypertension was diagnosed in 10 patients (20%). High tricuspid regurgitant jet velocity was found in 14% of adults and in 25% of children. Pulmonary function test including CO diffusion testing results were not different between the TM patients with or without pulmonary hypertension. In conclusion, PHT was frequent among TM patients even they were asymptomatic and although PFT results has shown lack of association, it should be investigated in larger population.

Pulmonary complications of hemoglobinopathies

Hemoglobinopathies are diseases caused by genetic mutations that result in abnormal, dysfunctional hemoglobin molecules or lower levels of normal hemoglobin molecules. The most common hemoglobinopathies are sickle cell disease (SCD) and the thalassemias. In SCD, an abnormal hemoglobin alters the erythrocyte, causing a chronic hemolytic anemia, which can lead to pulmonary parenchymal damage and impaired vascular function. Pulmonary complications of SCD include the acute chest syndrome (ACS), reactive airways disease, pulmonary hypertension (PH), and pulmonary fibrosis. Episodes of ACS and the development of PH both increase the risk of death in patients with SCD. Both α and β thalassemia are characterized by impaired production of hemoglobin subunits, and severity of disease varies widely. Although screening studies suggest that PH is a common complication for patients with thalassemia, its impact on survival is unknown. Understanding the pathogenesis, diagnostic options, and prevention and treatment strategies for such complications is critical for clinicians who care for these patients. In this review, we discuss the mechanisms and clinical presentation of pulmonary complications associated with hemoglobinopathies, with a focus on recent advances in pathogenesis and treatment.

Echocardiographic finding in beta-thalassemia intermedia and major: absence of pulmonary hypertension following hydroxyurea treatment in beta-thalassemia intermedia

OBJECTIVES

The aim of this study was to investigate the echocardigraphic finding in beta-thalassemia intermedia (TI) and beta-thalassemia major (TM) and to compare this finding together and with healthy control subjects.

METHODS

Fifty TI, who have been treated with hydroxyurea (HU) for 7 yrs and 51 transfusion dependent TM were compared with 50 age and sex matched healthy control subjects. Left and right ventricular parameters, systolic and diastolic functions, stroke volume, cardiac index and indices of pulmonary hypertension (PHT) were determined by two-dimensional, M-mode echocardiography and Doppler echocardiography.

RESULTS

Left ventricular parameters such as left ventricular end diastolic diameter, left ventricular end systolic diameter and also interventricular septal diameter in systole and diastole were significantly higher in TI patients compared with TM and control group (P < 0.05). There was elevated left ventricular mass (LV mass) in TI and TM patients compared with controls (P < 0.05). Regarding the LV diastolic function indices, E and A were significantly higher in TI patients compared with TM patients and control which were compatible with high output state. Measurement of pulmonary acceleration time and tricuspid and pulmonary valve continuous-wave Doppler tracing in patients with tricuspid regurgitation and pulmonary insufficiency showed no difference between TI, TM and control group.

CONCLUSION

Both TI and TM patients who have no clinical signs of cardiac involvement have significant abnormalities in volume, mass and shape of the LV which may be the consequence of chronic anemia. We found the unexpected absence of PHT in TI patients who have been treated with HU. In conclusion Low dose HU treatment of TI patients may prevent the devastating complication of PHT.

A multivariate analysis of serum nutrient levels and lung function

Background

There is mounting evidence that estimates of intakes of a range of dietary nutrients are related to both lung function level and rate of decline, but far less evidence on the relation between lung function and objective measures of serum levels of individual nutrients. The aim of this study was to conduct a comprehensive examination of the independent associations of a wide range of serum markers of nutritional status with lung function, measured as the one-second forced expiratory volume (FEV₁).

Methods

Using data from the Third National Health and Nutrition Examination Survey, a US population-based cross-sectional study, we investigated the relation between 21 serum markers of potentially relevant nutrients and FEV₁, with adjustment for potential confounding factors. Systematic approaches were used to guide the analysis.

Results

In a mutually adjusted model, higher serum levels of antioxidant vitamins (vitamin A, beta-cryptoxanthin, vitamin C, vitamin E), selenium, normalized calcium, chloride, and iron were independently associated with higher levels of FEV₁. Higher concentrations of potassium and sodium were associated with lower FEV₁.

Conclusion

Maintaining higher serum concentrations of dietary antioxidant vitamins and selenium is potentially beneficial to lung health. In addition other novel associations found in this study merit further investigation.

Pulmonary function test in transfusion-dependent beta-thalassemia patients

Beta-thalassaemia is the most common hemoglobinopathies in our region with treatment of regular blood transfusion. Iron overload and hemosiderosis can cause organ involvement. Recent studies have focused on pulmonary involvement and pathophysiology of lung damage. The goal of this study was to investigate the pulmonary abnormalities in thalassemic patients in relation with sign and symptoms and iron overload. The authors studied pulmonary function test (PFT) at the Adult Thalassemia Clinic in Tehran. The history of blood transfusion, iron chelation, respiratory problems, and drug usage was taken. Physical examination, PFT, arterial blood gas (ABG), and chest X-ray (CXR) were done. In total, 139 patients were studied. The mean age was 21.1 years and mean duration of transfusion was 18 years. It was found that 133 patients (95.7%) did not have respiratory problems and only 6 (4.3%) had some respiratory complaints. In CXR, 100 patients (89.3%) had normal lung pattern and others (10.7%) had variable degrees of abnormal lung pattern. In ABG, mean of Po(2) was 73.5% and mean of O(2) saturation was 90.6%. In PFT, 101 patients (72.7%) had restrictive pattern, 35 (25.1%) had normal pattern, and 3 (2.2%) had combined pattern. According to vital capacity, the patients were placed in five categories: 54 patients (38.8%) normal, 37 (26.6%) mild, 35 (25.3%) moderate, 10 (7.2%) severe, and 3 (2.1%) extremely severe pulmonary deficit. There was no statistical significance between PFT results with all variables studied, except duration of blood transfusion, which may be considered a indirect effect of iron load (p = .05, r = .361). According to these results, restrictive pattern was the most common finding (72.7%) in PFT, while 95.7% of patients had no respiratory complaint, and in the chest X-ray group, 89.3% had normal pattern. The authors conclude that the lung may be considered a site for organ damage, and alteration of pulmonary function may be expected in transfusion-dependent patients in spite of no pulmonary symptoms or normal CXR. In recent years, because of new iron chelating drugs, doctors can expect thalassemic patients to have a long life-time and need to increase their quality of life. One way to do this is to evaluate the respiratory system by PFT to prevent the squeal of pulmonary disease.

Pulmonary function tests in children with beta-thalassemia major

Lung function abnormality is a known complication of thalassemia, but the results of studies in pulmonary function have been inconsistent. This study was conducted to describe the type of lung impairment in thalassemic children. Pulmonary function tests were conducted in 40 children with beta-thalassemia major, 23 males and 17 females. Tests included spirometry, total lung capacity (TLC), single breath diffusing capacity of the lung for carbon monoxide (DL(CO)) and arterial blood gases. Serum ferritin level was measured in all children to study its relationship to lung function impairment. A predominantly restrictive pattern was seen in 14 patients (35%). These patients had a significant reduction in RV, FVC, TLC and PEF with an FEV1/FVC ratio of more than 75%. Obstructive airway disease was found in six patients (15%), with an FEV1/FVC ratio less than 75%, increased RV and reduced FEF(25%-75%). Impairment of diffusion was found in 10 patients (25%), with DL(CO) reduced to less than 80% of the predicted value. Arterial blood gases results showed that no patient was hypoxic. No correlation was found between the severity of restrictive or obstructive disease and the serum ferritin level. There was a significant linear correlation between age and serum ferritin level (P < 0.019). Patients with thalassemia have a predominantly restrictive lung dysfunction pattern. This may be due to pulmonary parenchymal pathology, although the reason for the obstructive pattern seen in a small proportion of patients remains obscure.

Study of pulmonary function tests in thalassemic children

The present study aimed to investigate pulmonary function tests (PFTs) in children with thalassemia and to assess the relation between the degree respiratory impairment with the body iron status. High resolution computed tomography of chest (CHRCT) and bronchoalveolar lavage (BAL) was performed to study the cause of pulmonary dysfunction. Thirty-one children with thalassemia over 8 years were included. PFTs were studied including lung volumes and carbon monoxide diffusion capacity (DLco). Patients with abnormal PFTs and/or impaired DLco were further subjected to CHRCT and BAL. Total cell count was measured; differential count was performed on Giemsa and PAP smears. Iron laden macrophages were identified on Perl's stain. PFTs were normal in 51.61%, diffusion capacity impaired in 41.16%, restriction in 16.12%, while obstruction in 3.22% of cases, respectively. There was significant inverse correlation between DLco and serum ferritin. Through multivariate regression analysis, ferritin was found to be a strong predictor for forced vital capacity and total lung capacity. Bronchial dilatation and areas of air trapping were the predominant CHRCT findings. Iron laden macrophages were demonstrated in 14 of 15 patients in BAL. A significant correlation between serum ferritin and DLco, forced vital capacity, total lung capacity, and the presence of iron laden macrophages in BAL indicates that iron plays a major role in the etiopathogenesis of these abnormalities.

Quantification of siderophages in bronchoalveolar fluid in transfusional and primary pulmonary hemosiderosis

Transfusional iron overload may occur in the lungs. We hypothesized that quantitating siderophages in the bronchoalveolar fluid (BALF) of heavily transfused patients may prove to be a useful tool in determining lung iron overload in transfusion-dependent patients. The study included six patients (7-20 years) with thalassemia major (TM) who had received multiple blood transfusions, one with hereditary spherocytosis (four blood transfusions) and one with sickle cell disease (never transfused); they were compared to three children with idiopathic pulmonary hemosiderosis (IPH) (2.5-7.0 years) as positive controls. Fiberoptic bronchoscopy with bronchoalveolar lavage was performed in seven patients under general anesthesia for elective surgery and the rest were bronchoscoped electively under sedation. Spirometry was also performed in eight patients. There was no significant difference between children with TM and IPH in siderophages as percentage of total count (95% CI -31.0 to 1.5, P = 0.068). There were positive relationships between both mean serum ferritin values during the preceding year and the total number of units of transfused blood, and percent siderophage count among multiply transfused patients (P = 0.010, P = 0.052, respectively); similar findings were noted for the Golde score (P = 0.001, P = 0.031, respectively). None of the patients showed lung function impairment. In conclusion, in this small study, we found that the BALF of multiply transfused patients with benign hematological disorders contain similar numbers of siderophages to that of patients with IPH; this is strongly suggestive of secondary pulmonary hemosiderosis. The correlation between the patients' serum ferritin, and the BALF siderophages suggests that the later may serve as a marker of pulmonary iron overload in patients requiring blood transfusion and appear to be more sensitive than standard pulmonary function tests.

Pulmonary hypertension in thalassemia: association with platelet activation and hypercoagulable state

The pathogenesis of pulmonary hypertension (PAH), a serious complication in thalassemia, is not well understood. Thromboembolism has been postulated as one of the causative factors; however, there are currently limited specific data on its role. To examine whether increased platelet activation and hypercoagulability are linked to PAH, 25 beta-thalassemia major and beta-thalassemia intermedia patients were evaluated with Doppler echocardiograms for estimation of pulmonary artery pressure and with laboratory assays for indications of a prothrombotic state. The association of clinical variables and abnormal coagulation assays with PAH was determined. PAH was identified in 17 (68%) patients; mean pulmonary artery systolic pressure was 39.8 +/- 5.4 mm Hg. PAH was significantly associated with prior splenectomy, older age, and evidence for chronic hemolysis, diagnosed in both transfused (n = 10) and nontransfused (n = 7) patients. Increased platelet activation, measured by P-selectin, was significantly associated with PAH (P = 0.001). Increased thrombin-antithrombin III level was more prevalent in the presence of PAH, but increased fibrinolysis or low protein C levels were not. This study underscores the role of platelet activation in the development of PAH and stresses its occurrence even among patients who are regularly transfused, especially those who are older and have had splenectomies.

Lung function in beta-thalassemia patients: a longitudinal study

Patients with beta-thalassemia often present with a restrictive pattern at pulmonary function tests (PFTs) due to several pathogenetic factors. However, the long-term evolution is unknown. We performed a longitudinal study of pulmonary function in asymptomatic, non-smoking patients with beta-thalassemia major and intermedia. We looked for temporal changes in lung function and characteristics that would predict the development of PFT abnormalities. In 1996, 18 patients with major beta-thalassemia (9 males and 9 females; age range: 18-35 years) and 11 patients with intermediate beta-thalassemia (5 males and 6 females; age range: 25-51 years) underwent clinical assessment and PFT, including body plethysmography and gas transfer study (carbon monoxide diffusion capacity, DL(CO)). Patients were reassessed in 2003. An echocardiographic evaluation was also obtained to exclude pulmonary hypertension. In 55.5% of major and 45.4% of intermediate beta-thalassemia patients, a restrictive pattern was found in 1996; in 2003 only 38.8 and 27.2% of patients, respectively, exhibited total lung capacities below the predicted values. DL(CO) was unchanged in both groups of patients, being reduced in 5 thalassemia major patients and within the normal range in intermediate patients. We conclude that asymptomatic patients with beta-thalassemia have a high prevalence of PFT abnormalities, but without significant increases over time. An improvement may be observed when good control of the iron balance is reached with optimal chelation therapy.

Heart failure in beta-thalassemia syndromes: a decade of progress

The thalassemias are common monogenic disorders of hemoglobin synthesis. beta-thalassemias are the most important among the thalassemia syndromes and have become a worldwide clinical problem due to an increasing immigrant population. In beta-thalassemia major, regular blood transfusions are necessary early in life. Beta-thalassemia intermedia refers to a less severe phenotype, whereas beta-thalassemia/hemoglobin E disease encompasses a broad phenotypic spectrum. Blood transfusions and increased gastrointestinal iron absorption result in iron overload and tissue damage. Among patients with beta-thalassemia major, biventricular, dilated cardiomyopathy remains the leading cause of mortality. In some patients, a restrictive type of left ventricular cardiomyopathy or pulmonary hypertension is noted. The clinical course, although variable and occasionally fulminant, is more benign in recent than in older series. Myocarditis has been described as a cause of left-sided heart failure in younger patients. Pulmonary arterial hypertension is the principal cause of heart failure in beta-thalassemia intermedia. Chelation therapy has improved prognosis in beta-thalassemia major both by reducing the incidence of heart failure and by reversing cardiomyopathy. Estimation of the patient's cardiac risk is mainly based on clinical criteria and serial echocardiography. A new cardiovascular magnetic resonance technique will probably fulfill the need for more precise risk stratification in beta-thalassemia syndromes. By increasing the proportion of patients on optimal chelation, survival in beta-thalassemia major may further improve. Recent advances in gene therapy are expected to result in the long-awaited cure of this disease.

Hydrops fetalis caused by homozygous alpha-thalassemia and Rh antigen alloimmunization: report of a survivor and literature review

Hematologic causes of hydrops fetalis include homozygous alpha-thalassemia and immune hemolytic anemias. We report the case of a boy with hydrops fetalis who had homozygous alpha-thalassemia and alloimmune hemolytic anemia due to anti-E and anti-C blood group antibodies. He received intrauterine red blood cell transfusions and postnatal chronic transfusion with iron chelation therapy. A non-myeloablative sibling stem cell transplant failed. He is now 5 years and 6 months of age, hypothyroid with short stature, but in overall good health. He is one of the oldest reported homozygous alpha-thalassemia survivors and, to our knowledge, the only survivor with immune- and nonimmune-induced hydrops fetalis.

β-Thalassemia Major: Thin-Section CT Features and Correlation with Pulmonary Function and Iron Overload

PURPOSE

To describe and quantify thin-section computed tomographic (CT) features of the lung in patients with beta-thalassemia major (beta-TM) and determine the correlation between thin-section CT findings, pulmonary function test (PFT) results, and iron overload.

MATERIALS AND METHODS

Forty-one patients with beta-TM (mean age, 24.5 years) underwent thin-section CT (during full inspiration and expiration) and PFTs. Two radiologists in consensus recorded the presence of focal bronchial and parenchymal abnormalities and air trapping. A semiquantitative air trapping score (ATS) was used, and patients were separated into air trapping-negative (ATS between 0 and 3) and air trapping-positive (ATS > 3) groups for statistical analysis. Iron overload was estimated by calculating the ratio of the signal intensity (SI) of the liver to the SI of paraspinous muscle by using magnetic resonance imaging in 27 patients (66%). We performed multiple logistic regression analysis to study the influence of age, PFT findings, and SI ratio on the presence of air trapping at CT and multivariate regression analysis to study the simultaneous influence of the presence of air trapping on obstructive PFT indexes.

RESULTS

Air trapping was the predominant thin-section CT finding and was seen in 10 (24%) of 41 patients. No patient had interstitial lung disease at CT, although 11 (27%) had a restrictive spirometric pattern. Simple logistic regression analysis revealed significant associations between ATS and forced expiratory volume in the first second (FEV1), FEV1/forced vital capacity (FVC), forced expiratory flow (FEF) in the midexpiratory phase (FEF25%-75%), FEF at 50% of the FVC (FEF50%), and FEF at 75% of the FVC (FEF75%) (P =.019,.030,.007,.034, and.021, respectively) but not between ATS and SI ratio. At multiple logistic regression analysis, only FEF25%-75% was significantly associated with ATS (P =.019, adjusted odds ratio = 0.86, R2 = 41.8%). Multivariate analysis revealed that ATS did not have a significant influence on lung function indexes (P =.104), although significant effects were found with FEV1, FEF25%-75%, FEF50%, and FEF75% when examined separately.

CONCLUSION

Air trapping may be present at expiratory thin-section CT in patients with beta-TM and is associated with reduced FEF25%-75% values but not hepatic iron overload.

Pulmonary dysfunction in transfusion-dependent patients with thalassemia major

Pulmonary function tests were performed on 62 transfusion-dependent patients with thalassemia major, ranging in age from 8 to 33 years, and receiving chelation therapy with desferrioxamine or deferiprone. Percent predicted values for FVC, FEV1, and PEF were significantly reduced, whereas FEV1/FVC and maximal expiratory flow at 25% FVC were within normal limits, indicating a restrictive disease. Both FVC and FEV1 were negatively correlated with transfusional iron burden as indexed by age. Single-breath carbon monoxide transfer factor was reduced, even after correction for low hemoglobin concentration, and was negatively correlated with iron burden and iron overload, as indexed by serum ferritin levels. Owing to low hemoglobin concentration, blood-diffusing capacity was reduced, in spite of increased lung capillary blood volume, which was, however, adequate to normalize blood diffusing capacity when hemoglobin concentration was only partially restored by transfusion. The diffusing capacity of the alveolar-capillary membrane was substantially decreased and negatively correlated with age and serum ferritin, the fall being primarily attributed to increased membrane thickness. These findings suggest that lung fibrosis and/or interstitial edema related to iron overload are the main cause of pulmonary dysfunction observed in patients with thalassemia major.

Respiratory function in patients with thalassaemia major: relation with iron overload

AIMS

(1) To determine the pattern of respiratory impairment in children with thalassaemia major (TM); (2) to assess the relation between the degree of respiratory impairment and total body iron content.

METHODS

Twenty nine TM patients were recruited. All underwent physical examination, standardised pulmonary function tests (spirometry, lung volume, and single breath diffusion capacity for carbon monoxide), and magnetic resonance imaging measurements of the liver. Serum ferritin was measured. The signal intensity ratio of liver to that of paraspinal muscle (T1 weighted sequence) and serum ferritin were used as surrogate index of body iron content.

RESULTS

Sixteen boys and 13 girls (median age 14.2 years) were studied. None had clinical evidence of congestive heart failure. Sixteen had normal lung function. Impairment of diffusion capacity (median DL(co) 83.5% predicted) was the most common abnormality, being observed in 34% of patients. Pure restrictive and obstructive ventilatory impairment was found in one and two patients respectively. Five patients had a combination of ventilation and diffusion defects. There was no correlation between the degree of impairment of each respiratory abnormality and body iron content.

CONCLUSION

Diffusion impairment was the commonest abnormality found in our cohort of paediatric TM patients. Our data did not support the notion that respiratory function impairment was correlated with body iron content.

Pulmonary hypertension, interstitial lung fibrosis, and lung iron deposition in thalassaemia major

Although restrictive lung disease is the predominant abnormality of pulmonary function in patients with thalassaemia major (TM), its aetiology and its association with pulmonary hypertension (PH) detected in some patients with TM remains unknown. We report a patient with TM, iron overload, frequent pulmonary infections, and progressive severe precapillary PH over the previous 5 years. A severe restrictive pattern and interstitial lung fibrosis were revealed by pulmonary function tests and high resolution computed tomography, respectively. This presentation suggests that interstitial fibrosis may complicate lung involvement in TM and can significantly contribute to the development of PH.

Cardiac involvement in thalassemia intermedia: a multicenter study

Cardiac complications in 110 patients (mean age, 32.5 ± 11.4 years) with thalassemia intermedia (TI) were studied. Sixty-seven (60.9%) of them had not been transfused or were minimally transfused (group A). The rest had started transfusions after the age of 5 years (mean, 15.1 ± 10.1 years), initially on demand and later more frequently (group B). Overall mean hemoglobin and ferritin levels were 9.1 ± 1.1 g/dL and 1657 ± 1477 ng/mL, respectively. Seventy-six healthy controls were also studied. The investigation included thorough history taking, clinical examination, electrocardiography, chest radiograph, and full resting echocardiography. Of 110 patients, 6 (5.4%) had congestive heart failure (CHF), and 9 (8.1%) had a history of acute pericarditis. Echocardiography showed pericardial thickening, with or without effusion, in 34.5% of the patients. Valvular involvement included leaflet thickening (48.1%), endocardial calcification (20.9%), and left-sided valve regurgitation (aortic, 15.4%; mitral, 47.2%). All patients had normal left ventricular contractility (fractional shortening, 0.43 ± 0.05), and high cardiac output (CO; 9.34 ± 2.28 L/min). Pulmonary hypertension (PHT), defined as Doppler peak systolic tricuspid gradient greater than 30 mm Hg, developed in 65 patients (59.1%). PHT correlated positively with age and CO and did not differ significantly between groups. Cardiac catheterization in the 6 patients with CHF revealed severe PHT, increased pulmonary resistance (PVR), and normal capillary wedge pressure. It was concluded that in patients with TI, the heart is primarily affected by PHT, which is the leading cause of CHF. High CO resulting from chronic tissue hypoxia and increased PVR are the main contributing factors. Doppler tricuspid gradient measurement should be considered, in addition to other factors, when determining the value of transfusion therapy for patients with TI.

Pulmonary function tests in beta thalassemia

To study pulmonary function tests (PFT) in multiple transfusion recipient thalassemics, PFTs were done for 30 thalassemics and 20 matched controls. Confirmed cases of thalassemia on regular transfusion therapy were the subject of study. Apart from history and physical examination of the thalassemics, serum ferritin estimation and spirometry were done. Parameters studied included lung volumes--functional residual capacity (FRC), forced vital capacity (FVC), residual volume (RV) and total lung capacity (TLC); and flow rates--forced expiratory volume in one second (FEV1), forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC), peak expiratory flow 25-75 (PEF 25-75%) and peak expiratory flow rate (PEFR). Single breath carbon monoxide diffusing capacity (DLco) and arterial blood gas (ABG) were also analysed. The mean height and weight of thalassemics were below that of age matched controls. A restrictive abnormality in PFT was found in 86.6% cases. These patients were found to have a decrease in all the lung volumes namely FVC, FRC, RV and TLC with a proportional decrease in the flow rates, FEV1, PEF 25-75% and PEF with a normal (> 0.75) FEV1/FVC ratio. DLco was decreased in all the patients with restrictive lung disease and fall in DLco showed a good correlation (r = 0.7, P < .001) with the severity of restrictive disease suggesting that some intrapulmonary pathology is likely to be responsible for the restrictive pattern. None of the cases had an obstructive or mixed pattern of pulmonary dysfunction. No correlation was found between severity of restrictive disease and the serum ferritin levels. A negative correlation with degree of hepatosplenomegaly was found. No correlation was found between severity of the defect and age, number of blood transfusions received and hemoglobin at the time of doing the test. To conclude, restrictive lung disease is the predominant abnormality in multi-transfused thalassemics, which is probably due to pulmonary parenchymal pathology. The abnormality of PFTs is not directly related to iron overload.

Effect of the Leukostop filter on pulmonary function following blood transfusion in patients with thalassemia major

This study evaluated the effect of the Leukostop filter, a device which reduces the number of leukocytes in blood, on pulmonary function in 15 patients with thalassemia major. Spirometry and oxygen saturation were used to evaluate the influence of filtering the blood. The transfusions consisted of blood which had or had not passed through a Leukostop filter. Blood transfusion induced a significant drop in FEV(1)/FVC ratio in 4 patients, an effect which disappeared following use of the Leukostop filter. Oxygen saturation improved after 6 months of using the Leukostop filter and improved acutely following blood transfusion (both with and without the filter). We conclude that removing most of the leukocytes from the blood during transfusions prevents bronchoconstriction and improves oxygen saturation.