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

Few reports exist concerning heart transplantation in recipients with end-stage myocardiopathy-associated heart failure caused by iron overload occurring with beta-thalassaemia, Diamond-Blackfan syndrome or haemochromatosis. Seven potential transplant candidates (six male, one female, mean age 26 years) with such heart failure, following desferrioxamine application subcutaneously over a number of years, and intravenously during their hospitalization before transplantation, were retrospectively analysed. Five were New York Heart Association (NYHA) class IV, three experienced one or more resuscitations immediately before transplantation could be performed. Continuous, high-volume, veno-venous haemofiltration was necessary in two patients. One of these two candidates additionally had to be bridged, first with a right ventricular, then with a biventricular assist device. Five of the seven patients survived, two with haemochromatosis, one with beta-thalassaemia major and one with Diamond-Blackfan syndrome following transplantation. One non-transplanted candidate with beta-thalassaemia major has been recompensated for 5 years. Survival was 14-74 months. Our results demonstrate the feasibility and indication of transplantation in patients with such heart failure and the satisfying outcome of immunosuppression is described.
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PMID:Heart transplantation for end-stage heart failure caused by iron overload. 916 90

Desferrioxamine (DFX) remains the most effective and safe iron chelator for treatment of patients with transfusional iron overload. It is usually given by intermittent subcutaneous infusions for 8-12 h on 4-6 days weekly using a battery-driven pump. Disposable balloon infusers provide a suitable method of giving continuous subcutaneous infusions with improved patient compliance. For patients with cardiac abnormalities due to iron overload, continuous intravenous desferrioxamine is essential to eliminate toxic plasma non-transferrin bound iron and to reduce body iron stores. Deferiprone (L1, l-2 dimethyl-3hydroxy-pyrid-4-one) is a less effective iron chelator but has the advantage of being orally active. Long-term trials in which patients have taken 75 mg/kg/day have shown that deferiprone is capable of maintaining body iron stores at safe levels in a proportion of thalassaemia major patients but body iron stores, assessed by liver biopsy remain at high levels (> 15.0 mg/g dry weight) in a substantial number of patients. These concentrations have been associated with tissue damage. Trials of increased doses of deferiprone (up to 100 mg/kg/day) or of combined therapy with daily deferiprone and DFX or 1 or 2 days each week are being carried out in an attempt to achieve lower body iron burden in these patients. Preliminary results show that the drugs can be given safely together and urine iron excretion produced is additive, implying that the drugs chelate different body iron pools. Patients previously well chelated with serum ferritin levels less than 2500 micrograms/L have the fewest side-effects from deferiprone and usually may be kept at the same level of body iron for periods of at least 4 years, assessed by serum ferritin and urine iron excretion. The side-effects of deferiprone result in some patients discontinuing therapy. These side-effects, especially arthropathy, mainly occur in previously poorly chelated and so the most heavily iron-loaded patients. Nausea and other gastrointestinal symptoms, agranulocytosis or milder degrees of neutropenia account with arthropathy for nearly all the withdrawals from deferiprone therapy. Patients with cardiomyopathy due to iron overload should be given intravenous DFX rather than deferiprone. Deferiprone, licensed for pharmaceutical use in India, awaits official approval for widespread clinical use in Western Europe and North America. Meanwhile, attempts to find new orally active iron chelators and improved methods of administration of desferrioxamine are in progress.
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PMID:Iron chelation therapy. 935 Jan 80

Thromboembolic (TE) events have been frequently reported in beta-thalassemic patients in association with known risk factors such as diabetes, complex cardiopulmonary abnormalities, hypothyroidism, liver function anomalies, and postsplenectomy thrombocytosis. In a recent survey involving 9 Italian thalassemic centers, we identified 32 patients with TE episodes in a total of 735 subjects, of whom 683 had thalassemia major and 52 thalassemia intermedia, corresponding to 3.95 and 9.61%, respectively. There was a great variation in localization: the main one (16/32) was CNS, with a clinical picture of headache, seizures and hemiparesis. Other localizations were the pulmonary (3 patients), mesenteric (1 patient) and portal (2 patients) sites. There were 6 cases of deep venous thrombosis (2 in the upper limbs, 4 in the lower ones). Intracardiac thrombosis was found in 2 subjects and clinical and laboratory signs of DIC were observed in 2 others during pregnancy. Since our patients with TE events present a statistically significantly higher incidence of associated dysfunction (cardiomyopathy, diabetes, liver function anomalies, hypothyroidism) than those without TE events (50 vs. 13.8%), we suggest close monitoring of those patients who are at higher risk of developing TE events because of the presence of one or more of these predisposing factors.
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PMID:Thromboembolic events in beta thalassemia major: an Italian multicenter study. 985 99

In thalassemia, iron overload is the joint outcome of excessive iron absorption and transfusional siderosis. While iron absorption is limited by a physiologic ceiling of about 3 mg/d, plasma iron turnover in thalassemia may be 10 to 15 times normal, caused by the wasteful, ineffective erythropoiesis of an enormously expanded erythroid marrow. This outpouring of catabolic iron exceeds the iron-binding capacity of transferrin and appears in plasma as non-transferrin-plasma iron (NTPI). The toxicity of NTPI is much higher than of transferrin-iron as judged by its ability to promote hydroxyl radical formation resulting in peroxidative damage to membrane lipids and proteins. In the heart, this results in impaired function of the mitochrondrial respiratory chain and abnormal energy metabolism manifested clinically in fatal hemosiderotic cardiomyopathy. Ascorbate increases the efficacy of iron chelators by expanding the intracellular chelatable iron pool, but, at suboptimal concentrations is a pro-oxidant, enhancing the catalytic effect of iron in free radical formation. NTPI is removed by i.v. DFO in a biphasic manner and reappears rapidly upon cessation of DFO, lending support to the continuous, rather than intermittent, use of chelators. Unlike DFO and other hexadentate chelators, bidentate chelators such as L1 may produce incomplete intermediate iron complexes at suboptimal drug concentrations.
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PMID:Pathophysiology of iron overload. 966 40

Patients with homozygous beta-thalassemia are chronically transfused and, if not assiduously chelated, are at risk for cardiac dysfunction. Available data suggest that even in optimally chelated patients, cardiac pathology is abnormal secondary to iron deposition, fibrosis, hypertrophy, and the structural effects of chronic anemia. Evidence of myopericarditis may also be found. Cardiac performance is usually only subtly affected, primarily with diastolic abnormalities not routinely detected on echocardiograms or nuclear scan. In poorly chelated patients, severe heart failure occurs and is easily predictable but invariably fatal, despite treatment with diuretics, vasodilators, inotropes, and antiarrhythmics. Based on successful prevention of heart failure with ACE inhibitors in other forms of cardiomyopathy, we suggest multicenter trials to explore methods to stabilize cardiac function in patients at risk for iron-induced heart disease. Long-term adverse effects of iron deposition, diastolic dysfunction, and abnormal hormone regulation need to be quantitated in patients reaching their third and fourth decades when the potential for ischemic cardiac disease could compound cardiac dysfunction.
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PMID:Diagnosis and management of iron-induced heart disease in Cooley's anemia. 966 46

It is known that a blood transfusion is necessary for survival in patients with thalassemia, but it may cause myocardial dysfunction due to myocardial siderosis as in other organs. The aim of this study was to evaluate myocardial perfusion by means of stress thallium scanning (MPS) and left ventricular functions by rest radionuclide ventriculography (RNV). Twenty-one patients at ages 9-16 (mean 12.1 +/- 3.2) who have been diagnosed with thalassemia for 4-15 years (mean 12.7 +/- 4.8) were included in the study. They had blood transfusions 78-318 times (mean 162.1 +/- 71). MPS and RNV was performed within two days after the any transfusion. MPS showed ischemia in 3 patients and normal perfusion in 18 patients. RNV revealed normal systolic parameters (wall motion, EF, PER, TPE) but diminished diastolic parameters (TPF, PFR) compared with normal values (p < 0.05). We conclude that ischemia or fixed defects may be seen in stress MPS as a result of cardiac involvement in patients with thalassemia. But, RNV is an important and preferable test for the early detection of subclinic cardiomyopathy. RNV may therefore show diastolic abnormalities before the systolic abnormalities show up.
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PMID:Evaluation of cardiac functions in patients with thalassemia major. 1043 78

Heart failure remains the main cause of death in beta-thalassemia despite the progress that has been made. Myocardial iron deposition alone does not affect left ventricular relaxation but directly causes left ventricular myocardial restriction with considerably elevated pulmonary pressure. This leads to symptoms and signs of predominantly right-sided heart failure, which is usually observed in elderly and severely hemosiderotic populations. Left ventricular systolic dysfunction and failure, which occurs in younger, less hemosiderotic populations, seems to be multifactorial in etiology. Apart from iron loading, immunogenetic risk factors trigger the mechanisms of left-sided heart failure development in the context of dilated-type cardiomyopathy. (c)2001 CHF, Inc.
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PMID:Heart failure in beta-thalassemia. 1182 76

The natural history of thalassemia has shown substantial change during these years. This applies for each aspect of the pathology (for example, endocrinological, hepatological and psychological) and also for the pathology that has presented and still presents the main cause of death: myocardial dysfunction. In this review, the pathophysiology of cardiac complications, possible role of myocarditis, new knowledge on pathogenesis, and noninvasive detection methods for iron overload in the heart are pointed out. Prophylaxis of cardiomyopathy and new therapy strategies of myocardial dysfunction, including the impact of the new chelation treatment, are discussed.
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PMID:Cardiac complications in thalassemia: noninvasive detection methods and new directions in the clinical management. 1503 Feb 71

Heart failure from iron overload causes 71% of deaths in thalassaemia major, yet reversal of siderotic cardiomyopathy has been reported. In order to determine the changes in myocardial iron during treatment, we prospectively followed thalassaemia patients commencing intravenous desferrioxamine for iron-induced cardiomyopathy during a 12-month period. Cardiovascular magnetic resonance assessments were performed at baseline, 3, 6 and 12 months of treatment, and included left ventricular (LV) function and myocardial and liver T2*, which is inversely related to iron concentration. One patient died. The six survivors showed progressive improvements in myocardial T2* (5.1 +/- 1.9 to 8.1 +/- 2.8 ms, P = 0.003), liver iron (9.6 +/- 4.3 to 2.1 +/- 1.5 mg/g, P = 0.001), LV ejection fraction (52 +/- 7.1% to 63 +/- 6.4%, P = 0.03), LV volumes (end diastolic volume index 115 +/- 17 to 96 +/- 3 ml, P = 0.03; end systolic volume index 55 +/- 16 to 36 +/- 6 ml, P = 0.01) and LV mass index (106 +/- 14 to 95 +/- 13, P = 0.01). Iron cleared more slowly from myocardium than liver (5.0 +/- 3.3% vs. 39 +/- 23% per month, P = 0.02). These prospective data confirm that siderotic heart failure is often reversible with intravenous iron chelation with desferrioxamine. Myocardial T2* improves in concert with LV volumes and function during recovery, but iron clearance from the heart is considerably slower than from the liver.
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PMID:Myocardial iron clearance during reversal of siderotic cardiomyopathy with intravenous desferrioxamine: a prospective study using T2* cardiovascular magnetic resonance. 1549 Dec 98

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


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