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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cardiac disease is the primary cause of mortality in beta-thalassemia patients. Except for ventricular dysfunction and pulmonary hypertension that represent the main forms of heart disease in these patients, valvular abnormalities including valvular regurgitation, endocardial thickening and calcification and mitral valve prolapse have also been described. Here we present two patients with thalassemia major and mitral chordal rupture, a previously undescribed abnormality in this population. Pathogenesis of this finding may involve thalassemia-related pseudoxanthoma elasticum-like syndrome, a diffuse elastic tissue defect, which is observed with a notable frequency in these patients and has been associated with numerous cardiovascular complications, including valvular ones.
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PMID:Rupture of chordae tendineae in patients with beta-thalassemia. 1508 70

New developments in the epidemiology, treatment and prognosis of thalassemia have dramatically altered the approach to the care of affected patients, and these developments are likely to have an even greater impact in the next few years. Demographic changes have required an awareness and understanding of the unique features of thalassemia disorders that were previously uncommon in North America but are now seen more frequently in children and recognized more consistently in adults. New methods for measuring tissue iron accumulation and new drugs to remove excessive iron are advancing two of the most challenging areas in the management of thalassemia as well as other transfusion-dependent disorders. Improved survival of patients with thalassemia has given new importance to adult complications such as endocrinopathies and hepatitis that have a major impact on the quality of life. This chapter describes how these changes are redefining the clinical management of thalassemia. In Section I, Dr. Renzo Galanello describes recent advances in iron chelation therapy. Several new chelators are either licensed in some countries, are in clinical trials or are in the late stages of preclinical development. Some of these iron chelators, such as deferiprone (DFP) and ICL670, are orally active. Others, such as hydroxybenzyl-ethylenediamine-diacetic acid (HBED) and starch deferoxamine, require parenteral administration but may be effective with less frequent administration than is currently required for deferoxamine. Chelation therapy employing two chelators offers the possibility of more effective removal of iron without compromising safety or compliance. Other strategies for chelation therapy may take advantage of the ability of particular chelators to remove iron from specific target organs such as the heart and the liver. In Section II, Dr. Dudley Pennell addresses cardiac iron overload, the most frequent cause of death from chronic transfusion therapy. The cardiac complications related to excessive iron may result from long-term iron deposition in vulnerable areas or may be due to the more immediate effects of nontransferrin-bound iron. Cardiac disease is reversible in some patients with intensive iron chelation therapy, but identification of cardiac problems prior to the onset of serious arrhythmias or congestive heart failure has proven difficult. New methods using magnetic resonance imaging (MRI) have recently been developed to assess cardiac iron loading, and studies suggest a clinically useful relationship between the results using these techniques and critical measures of cardiac function. Measurements such as T2* may help guide chelation therapy in individual patients and may also enhance the assessment of new chelators in clinical trials. The use of MRI-based technology also holds promise for wider application of non-invasive assessment of cardiac iron in the management of patients with thalassemia. In Section III, Dr. Melody Cunningham describes some of the important complications of thalassemia that are emerging as patients survive into adulthood. Hepatitis C infection is present in the majority of patients older than 25 years. However, antiviral therapy in patients with thalassemia has been held back by the absence of large clinical trials and concern about ribavirin-induced hemolysis. More aggressive approaches to the treatment of hepatitis C may be particularly valuable because of the additive risks for cirrhosis and hepatocellular carcinoma that are posed by infection and iron overload. Thrombosis is recognized with increasing frequency as a significant complication of thalassemia major and thalassemia intermedia, and pulmonary hypertension is now the focus of intense study. Risk factors for thrombosis such as splenectomy are being identified and new approaches to anticoagulation are being initiated. Pregnancies in women with thalassemia are increasingly common with and without hormonal therapy, and require a better understanding of the risks of iron overload and cardiac disease in the mother and exposure of the fetus to iron chelators. In Section IV, Dr. Elliott Vichinsky describes the dramatic changes in the epidemiology of thalassemia in North America. Hemoglobin E-beta thalassemia is seen with increasing frequency and poses a particular challenge because of the wide variability in clinical severity. Some affected patients may require little or no intervention, while others need chronic transfusion therapy and may be appropriate candidates for hematopoietic stem cell transplantation. Enhancers of fetal hemoglobin production may have a unique role in Hb E-beta thalassemia since a modest increase in hemoglobin level may confer substantial clinical benefits. Alpha thalassemia is also being recognized with increasing frequency in North America, and newborn screening for Hemoglobin Barts in some states is leading to early detection of Hb H disease and Hb H Constant Spring. New data clarify the importance of distinguishing these two disorders because of the increased severity associated with Hb H Constant Spring. The use of intrauterine transfusions to sustain the viability of fetuses with homozygous alpha thalassemia has created a new population of patients with severe thalassemia and has raised new and complex issues in genetic counseling for parents with alpha thalassemia trait.
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PMID:Thalassemia. 1556 74

Pulmonary hypertension is a common complication of sickle cell disease (SCD). In spite of the mild elevations in pulmonary artery pressures in these patients, the associated morbidity and mortality is high. In fact, in adult patients with SCD, pulmonary hypertension is emerging as the major independent risk factor for death. The aetiology of pulmonary hypertension is probably multifactorial, including haemolysis, impaired nitric oxide bioavailability, chronic hypoxaemia, thromboembolism, parenchymal and vascular injury because of sequestration of sickle erythrocytes, chronic liver disease and asplenia. Interestingly, pulmonary hypertension is emerging as a common, and probably, invariant sequella of lifelong haemolytic anaemia in other hereditary and acquired haemolytic diseases, such as thalassaemia, stomatocytosis and spherocytosis. There are currently limited specific data on the effects of any treatment modality for pulmonary hypertension in patients with SCD. It is likely that maximization of SCD therapy, in all patients, and treatment with selective pulmonary vasodilators and antiproliferative agents, in patients with severe disease, would be beneficial. A large trial evaluating the effects of therapy for pulmonary hypertension in the SCD population is clearly indicated.
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PMID:Chronic sickle cell lung disease: new insights into the diagnosis, pathogenesis and treatment of pulmonary hypertension. 1587 28

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.
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PMID:Heart failure in beta-thalassemia syndromes: a decade of progress. 1616 78

Medical advances in the management of patients with sickle cell disease, thalassemia, and other hemolytic anemias have led to significant increases in life expectancy. Improved public health, neonatal screening, parental and patient education, advances in red cell transfusion medicine, iron chelation therapy, penicillin prophylaxis for children, pneumococcal immunization, and hydroxyurea therapy have all likely contributed to this effect on longevity. Importantly, as a generation of patients with sickle cell disease and thalassemia ages, new chronic complications of these hemoglobinopathies develop. In this context, pulmonary hypertension is emerging as one of the leading causes of morbidity and mortality in adult sickle cell and thalassemia patients, and likely in patients with other hemolytic anemias. A common feature of both sickle cell disease and thalassemia is intravascular hemolysis and chronic anemia. Recent data suggest that chronic intravascular hemolysis is associated with a state of endothelial dysfunction characterized by reduced nitric oxide (NO) bioavailability, pro-oxidant and pro-inflammatory stress and coagulopathy, leading to vasomotor instability and ultimately producing a proliferative vasculopathy, a hallmark of which is the development of pulmonary hypertension in adulthood. In conclusion, pulmonary hypertension is common in patients with hereditary hemolytic anemias and is associated with a high risk of death in patients with sickle cell disease. New therapies targeting this vasculopathy and aimed at normalizing the vasodilator:vasoconstrictor balance are discussed.
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PMID:Cardiopulmonary complications of sickle cell disease: role of nitric oxide and hemolytic anemia. 1630 59

Cardiac involvement represents the leading cause of mortality in both forms of beta-thalassemia, namely, thalassemia major (TM) and thalassemia intermedia (TI), and pulmonary hypertension (PHT) is part of the cardiopulmonary complications of the disease. PHT was initially documented in a small group of TI patients with right heart failure. In a subsequent study of a large 110-patient series, aged 32.5 +/- 11.4 years, age-related PHT was encountered in nearly 60% of cases, having caused right heart failure in six of them; interestingly, all patients had preserved left ventricular systolic function. Conflicted evidence, however, existed with respect to the development of PHT in heterogeneously treated and young TM populations. To resolve this discrepancy, a recent study compared cardiac disease between two large aged-matched groups of TM (n = 131) and TI (n = 74) patients, both treated uniformly in the currently accepted manner (regular transfusion and chelation therapy in TM, absence of any particular treatment in TI); well-treated TM patients, in contrast to TI patients, did not develop PHT, while systolic left ventricular dysfunction was present only in TM cases. PHT in beta-thalassemia results from a rather complex pathophysiology, in which chronic tissue hypoxia seems to hold a key role. Although both forms of the disease share a common molecular background, the diverse severity of the genetic defect and of the resulting clinical phenotype require a different therapeutic approach. Regular lifelong therapy in TM patients eliminates chronic hypoxia, thereby preventing PHT, whereas the absence of systematic treatment in TI leads to a cascade of reactions that compensate for chronic anemia, but at the same time allow the development of PHT.
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PMID:Pulmonary hypertension in beta-thalassemia. 1633 82

Accumulating evidence supports the existence of a condition involving hemolysis-associated pulmonary hypertension (PHT). Hemolysis-induced release of cell-free hemoglobin and red blood cell arginase, resulting in impaired nitric oxide bioavailability, endothelial dysfunction, and PHT, has been reported in sickle cell disease. Since thalassemia is also a condition of chronic hemolysis, these patients are at risk. The data demonstrate that hemolysis-induced dysregulation of arginine metabolism and PHT also occurs in thalassemia. Erythrocyte release of arginase during hemolysis contributes to the development of PHT. Therapies that maximize arginine and nitric oxide bioavailability may benefit patients with thalassemia.
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PMID:Hemolysis-associated pulmonary hypertension in thalassemia. 1633 2

Pulmonary hypertension is common in adults with thalassaemia and other haemolytic anaemias. It was hypothesised that regular transfusions in thalassaemia major should both decrease the chronic haemolytic rate and be protective from pulmonary hypertension (PHT). To reduce the contribution of existing cardiac disease to PHT, the subjects were limited to patients with normal left ventricular shortening fractions. Associations with multiple laboratory markers of haemolysis, serum ferritin levels, chest X-rays findings and splenectomy status were also considered. We found no biochemical, transfusional, or clinical (except gender) differences in transfused thalassaemia patients with or without pulmonary hyper tension.
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PMID:Pulmonary hypertension in thalassaemia major patients with normal left ventricular systolic function. 1664 52

Pulmonary hypertension is a common complication of beta-thalassemia major. We report a case of successful treatment of pulmonary hypertension in a patient with beta-thalassemia major and review the literature on pulmonary hypertension and beta-thalassemia major. A 28-year-old man with beta-thalassemia major, splenectomy, hepatitis C, and hemosiderosis who presented with increasing dyspnea on exertion was diagnosed with pulmonary hypertension. After receiving continuous epoprostenol infusion and desferoxamine, his functional capacity and hemodynamic status improved. To our knowledge, this is the first case of pulmonary hypertension associated with beta-thalassemia treated with continuous epoprostenol infusion and desferoxamine. Epoprostenol, beneficial in the treatment of other types of pulmonary hypertension, may ameliorate the morbidity and mortality of pulmonary hypertension associated with thalassemia.
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PMID:Pulmonary hypertension and beta-thalassemia major: report of a case, its treatment, and a review of the literature. 1668 Jul 45

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.
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PMID:Pulmonary hypertension in thalassemia: association with platelet activation and hypercoagulable state. 1679 58


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