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

Cardiac damage caused by iron overload toxicity is the main cause of death in thalassemia patients. Biopsy samples of poorly chelated thalassemia patients who suffered congestive cardiac failure (CCF) show extensive iron deposition in the myocardium. In one patient who survived CCF, a cardiac biopsy was performed during the removal of a thrombus caused by a port-a-cath, which was used for the administration of intravenous (iv) deferoxamine (DFO). Ultrastructural pathology studies of the cardiac biopsy indicated extensive iron deposition in myocytes with accumulation of iron mainly in lysosomes, leading in some cases to their disruption. Damage to other intracellular components of the myocytes and loss of myofibers was also observed. The patient became intolerant to iv and subcutaneous (sc) DFO 2 years after the CCF, and was then treated with deferiprone (L1) for 7 years. Within 1 year of L1 treatment at 75-80 mg/kg/day, serum ferritin levels were reduced to <0.45 mg/L and she became asymptomatic, needing no further drugs for her cardiomyopathy. Lowering the L1 dose to 50-70 mg/kg/day caused an increase in serum ferritin levels. Maintenance of normal iron stores during the last 3 years as detected by cardiac and liver magnetic resonance imaging (MRI) T2 and T2* and normalization of serum ferritin levels (<0.15 mg/L) was observed following L1 therapy at 80-85 mg/kg/day. Deferiprone (>80 mg/kg/day) appears to be effective in the rapid clearance of cardiac iron, in the reversal of iron overload related cardiomyopathy, in the maintenance of normal iron stores and the overall long-term survival of thalassemia patients.
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PMID:Myocyte damage and loss of myofibers is the potential mechanism of iron overload toxicity in congestive cardiac failure in thalassemia. Complete reversal of the cardiomyopathy and normalization of iron load by deferiprone. 1827 79

The homozygous beta-thalassemias are a group of genetically inherited hemoglobin (Hb) disorders characterized by dyserythropoietic anemia. According to the degree of anemia, two main forms, sharing a common basic molecular mechanism, are distinguished: thalassemia major (TM) and thalassemia intermedia (TI). The severity of the clinical phenotype differentiates the two forms. Thalassemia major usually presents as a severe anemia requiring life-long transfusion therapy for survival. The dramatic improvement in life expectancy of beta-thalassemia (thal) patients achieved during the past few decades by virtue of therapeutic advances, has motivated investigators' interest in a better understanding of the clinical consequences of this genetic defect. Heart complications still represent the leading cause of mortality from the disease. The mechanisms of cardiac injury along with its treatment and prevention have attracted the main research efforts in this field. In this review, we present existing knowledge and our personal experience of 30 years of follow-up of over 1,000 thalassemic patients, regarding the basis of the cardiac injury, the clinical findings and the global strategy of the therapeutic intervention in TM patients who develop congestive heart failure (CHF).
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PMID:Congestive heart failure and treatment in thalassemia major. 1827 84

Thalassemia is anemia of variable severity, arising from mutations of genes encoding the hemoglobin alpha and beta chains. Severe thalassemia is associated with iron overload, tissue lesions, and high risk for cardiovascular complications, and iron-mediated cardiomyopathy is the main cause of death in this condition. Thalassemia major (TM) patients exhibit cardiovascular abnormalities consistent with chronic anemia; these include enlargement of the ventricular chambers, increased cardiac output, and reduced total vascular resistance. Cardiac iron overload in TM patients due to long-term transfusion can cause further chamber dilation, decreased contractility, and arrhythmia. Paradoxically, many such patients remain asymptomatic until decompensation occurs. For decades, magnetic resonance imaging and echocardiography have been performed to detect advanced cardiac dysfunction; however, reliable evaluation tools for the early detection of cardiac abnormalities are currently in demand. This article reviews the mechanisms underlying the development of heart disease in thalassemia and strategies for therapeutic intervention in TM patients with congestive heart failure.
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PMID:Mechanisms of and obstacles to iron cardiomyopathy in thalassemia. 1850 36

Cardiovascular involvement is a leading cause of mortality and morbidity in patients with inherited hemoglobinopathies, but it has not been adequately assessed in sickle beta-thalassemia. We evaluated 115 sickle beta-thalassemia patients, aged 34 +/- 14 years, along with 50 healthy controls, by resting echocardiography. Patients with systolic left ventricular (LV) dysfunction or severe pulmonary hypertension (PHT) also underwent left and right cardiac catheterization and cardiac magnetic resonance imaging (CMR). Left and right chamber dimensions, LV mass, and cardiac index were significantly higher in patients compared to controls (p < 0.001 in most cases). Three patients (2.9%) had reduced LV ejection fraction (<55%); mean LV ejection fraction was significantly lower in patients (p < 0.001). Left and right ventricular systolic tissue Doppler indices and LV diastolic tissue Doppler indices were also impaired in patients. All three patients with systolic LV dysfunction had normal coronary arteries and mild myocardial iron load (CMR T2* values, 18-25 ms). Systolic pulmonary artery pressure was significantly higher in patients compared to controls (p = 0.002); PHT was present in 28 patients (27%), while severe PHT in three (2.9%). In three patients with severe PHT, only one had impaired LV ejection fraction and increased pulmonary wedge pressure. Overall, three patients (2.9%) had a history of heart failure, two with systolic LV dysfunction, and one with severe PHT. Cardiac involvement in sickle beta-thalassemia concerns biventricular dilatation and dysfunction along with PHT, leading to congestive heart failure.
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PMID:Cardiac involvement in sickle beta-thalassemia. 1910 83

Excess cardiac iron deposition leads to congestive cardiac failure and accounts for more than 70% of deaths in thalassemia major patients. In three separate studies involving 145 thalassemia patients, serum ferritin and magnetic resonance imaging (MRI) relaxation times T2 and T2* have been compared for assessing iron load levels during chelation treatment. In two studies, variable levels of cardiac iron load have been detected by T2 and T2* in patients treated with deferoxamine (DFO), which, however, were unrelated to serum ferritin. In most cases, similar range levels from normal to severe cardiac iron load could be identified by both the T2 and T2* methods. However, in a few cases there were substantial differences in the levels detected between the two methods. In the third study, the ferrikinetics of the normalization of the iron stores during the International Committee on Chelation (ICOC) deferiprone (L1)/DFO combination protocol was followed up using T2 and T2* and serum ferritin. Iron deposits were found not to be proportionally distributed between the liver and the heart or uniformly distributed within each organ. Iron mobilization in each patient varied and iron deposits in each organ were cleared at different rates. Despite some limitations, the application of the MRI relaxation times T2 and T2* offers the best diagnostic methods for iron overload estimations in most organs and especially the heart. These MRI methods and serum ferritin could also be used for the ferrikinetics of iron mobilization and removal during chelation therapy and the normalization of the iron stores during the ICOC L1/DFO combination protocol. There is a need to standardize the two MRI relaxation times T2 and T2* methods and identify the factors causing the differences between them.
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PMID:Uses and limitations of serum ferritin, magnetic resonance imaging T2 and T2* in the diagnosis of iron overload and in the ferrikinetics of normalization of the iron stores in thalassemia using the International Committee on Chelation deferiprone/deferoxamine combination protocol. 1981 77

A new era in iron chelation therapy began with the successful removal of excess iron load and the maintenance of normal iron stores in thalassemia patients using the International Committee on Chelation (ICOC) protocols. This achievement was based on two phases, firstly the introduction of deferiprone (L1) (80-100 mg/kg/day) and deferoxamine (DFO) (40-60 mg/kg at least 3 days per week) combination therapy, which appears to progressively remove all excess storage iron and thereafter by the introduction of L1 monotherapy that can maintain physiological range levels of serum ferritin, cardiac and liver magnetic resonance imaging (MRI) T2*. This new development is likely to change current practices and set a new gold standard in the treatment of transfusional iron loaded patients leading to an increased survival and the change of thalassemia from a fatal to a chronic disease. A major aspect of the improved therapies is the ability of L1 to mobilize and remove excess cardiac iron and reduce congestive cardiac failure, which is the main cause of death in thalassemia patients. Further, new developments include the use of alternating sequential chelation therapies and selected dose protocols with L1, DFO and deferasirox (DFRA) for overcoming toxicity and efficacy complications observed in some patients treated with monotherapies or combination therapies. The selection and adjustment of dose protocols is crucial for providing optimum chelation therapy for each individual patient.
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PMID:A new era in iron chelation therapy: the design of optimal, individually adjusted iron chelation therapies for the complete removal of iron overload in thalassemia and other chronically transfused patients. 1981 79

Intracranial hemorrhage (ICH) is rarely seen in patients with thalassemia. A seven-year-old male, known case of beta-thalassemia major, on irregular packed cell transfusions (elsewhere) and non-compliant with chelation therapy, presented with congestive cardiac failure (Hb-3 gm/dl). He received three packed red cell transfusions over 7 days (cumulative volume 40 cc/kg). On the 9th day, he developed projectile vomiting and two episodes of generalized tonic-clonic convulsions with altered sensorium. He had exaggerated deep tendon reflexes and extensor plantars. CT-scan of brain revealed bilateral acute frontal hematoma with diffuse subarachnoid hemorrhage (frontal and parietal). Coagulation profile was normal. CT-angiography of brain showed diffuse focal areas of reduced caliber of anterior cerebral, middle cerebral, and basilar and internal carotid arteries (likely to be a spasmodic reaction to subarachnoid hemorrhage). He required mechanical ventilation for 4 days and conservative management for the hemorrhage. However, on the 18th day, he developed one episode of generalized tonic-clonic convulsion and his sensorium deteriorated further (without any new ICH) and required repeat mechanical ventilation for 12 days. On the 28th day, he was noticed to have quadriplegia (while on a ventilator). Nerve conduction study (42nd day) revealed severe motor axonal neuropathy (suggesting critical illness polyneuropathy). He improved with physiotherapy and could sit upright and speak sentences at discharge (59th day). The child recovered completely after 3 months. It is wise not to transfuse more than 20 cc/kg of packed red cell volume during each admission and not more than once in a week (exception being congestive cardiac failure) for thalassemia patients.
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PMID:Beta-thalassemia major complicated by intracranial hemorrhage and critical illness polyneuropathy. 3131 77


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