Management of thalassemia

About: Management of thalassemia is a research topic. Over the lifetime, 121 publications have been published within this topic receiving 8365 citations.

Cardiovascular T2-star (T2*) magnetic resonance for the early diagnosis of myocardial iron overload

Abstract: Aims To develop and validate a non-invasive method for measuring myocardial iron in order to allow diagnosis and treatment before overt cardiomyopathy and failure develops.Methods and Results We have developed a new magnetic resonance T2-star (T2*) technique for the measurement of tissue iron, with validation to chemical estimation of iron in patients undergoing liver biopsy. To assess the clinical value of this technique, we subsequently correlated myocardial iron measured by this T2* technique with ventricular function in 106 patients with thalassaemia major. There was a significant, curvilinear, inverse correlation between iron concentration by biopsy and liver T2* (r=0(.)93, P <0(.)0001). Inter-study cardiac reproducibility was 5(.)0%. As myocardial iron increased. there was a progressive decline in ejection fraction (r=0(.)61, P <0(.)001). All patients with ventricular dysfunction had a myocardial T2* of < 20 ms. There was no significant correlation between myocardial T2* and the conventional parameters of iron status, serum ferritin and liver iron. Multivariate analysis of clinical parameters to predict the requirement for cardiac medication identified myocardial T2* as the most significant variable (odds ratio 0(.)79, P <0(.)002).Conclusions Myocardial iron deposition can be reproducibly quantified using myocardial T2* and this is the most significant variable for predicting the need for ventricular dysfunction treatment. Myocardial iron content cannot be predicted from serum ferritin or liver iron, and conventional assessments of cardiac function can only detect those with advanced disease. Early intensification of iron chelation therapy, guided by this technique. should reduce mortality from this reversible cardiomyopathy. (C) 2001 The European Society of Cardiology.

Survival and complications in patients with thalassemia major treated with transfusion and deferoxamine

Abstract: BACKGROUND AND OBJECTIVES: Seven Italian centers reported data on survival, causes of death and appearance of complications in patients with thalassemia major. The interactions between gender, birth cohort, complications, and ferritin on survival and complications were analyzed. DESIGN AND METHODS: Survival after the first decade was studied for 977 patients born since 1960 whereas survival since birth and complication appearance was studied for the 720 patients born after 1970. Better survival was demonstrated for patients born in more recent years (p<0.00005) and for females (p=0.0003); 68% of the patients are alive at the age of 35 years. In the entire population 67% of the deaths were due to heart disease. RESULTS: There was a significant association between birth cohort and complication-free survival (p<0.0005). The prevalence of complications was: heart failure 6.8%, arrhythmia 5.7%, hypogonadism 54.7%, hypothyroidism 10.8%, diabetes 6.4%, HIV infection 1.7%, and thrombosis 1.1%. Lower ferritin levels were associated with a lower probability of heart failure (hazard ratio =3.35, p<0.005) and with prolonged survival (hazard ratio = 2.45, p<0.005), using a cut-off as low as 1,000 ng/mL. INTERPRETATION AND CONCLUSIONS: Survival and complication-free survival of patients with thalassemia major continue to improve, especially for female patients born shortly before or after the availability of iron chelation.

Beta-thalassemia

Abstract: Beta-thalassemias are a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. The total annual incidence of symptomatic individuals is estimated at 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Three main forms have been described: thalassemia major, thalassemia intermedia and thalassemia minor. Individuals with thalassemia major usually present within the first two years of life with severe anemia, requiring regular red blood cell (RBC) transfusions. Findings in untreated or poorly transfused individuals with thalassemia major, as seen in some developing countries, are growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, development of masses from extramedullary hematopoiesis, and skeletal changes that result from expansion of the bone marrow. Regular transfusion therapy leads to iron overload-related complications including endocrine complication (growth retardation, failure of sexual maturation, diabetes mellitus, and insufficiency of the parathyroid, thyroid, pituitary, and less commonly, adrenal glands), dilated myocardiopathy, liver fibrosis and cirrhosis). Patients with thalassemia intermedia present later in life with moderate anemia and do not require regular transfusions. Main clinical features in these patients are hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis and its complications (osteoporosis, masses of erythropoietic tissue that primarily affect the spleen, liver, lymph nodes, chest and spine, and bone deformities and typical facial changes), gallstones, painful leg ulcers and increased predisposition to thrombosis. Thalassemia minor is clinically asymptomatic but some subjects may have moderate anemia. Beta-thalassemias are caused by point mutations or, more rarely, deletions in the beta globin gene on chromosome 11, leading to reduced (beta+) or absent (beta0) synthesis of the beta chains of hemoglobin (Hb). Transmission is autosomal recessive; however, dominant mutations have also been reported. Diagnosis of thalassemia is based on hematologic and molecular genetic testing. Differential diagnosis is usually straightforward but may include genetic sideroblastic anemias, congenital dyserythropoietic anemias, and other conditions with high levels of HbF (such as juvenile myelomonocytic leukemia and aplastic anemia). Genetic counseling is recommended and prenatal diagnosis may be offered. Treatment of thalassemia major includes regular RBC transfusions, iron chelation and management of secondary complications of iron overload. In some circumstances, spleen removal may be required. Bone marrow transplantation remains the only definitive cure currently available. Individuals with thalassemia intermedia may require splenectomy, folic acid supplementation, treatment of extramedullary erythropoietic masses and leg ulcers, prevention and therapy of thromboembolic events. Prognosis for individuals with beta-thalassemia has improved substantially in the last 20 years following recent medical advances in transfusion, iron chelation and bone marrow transplantation therapy. However, cardiac disease remains the main cause of death in patients with iron overload.

Survival in medically treated patients with homozygous beta-thalassemia.

Abstract: Background The prognosis of patients with homozygous β-thalassemia (thalassemia major) has been improved by transfusion and iron-chelation therapy. We analyzed outcome and prognostic factors among patients receiving transfusions and chelation therapy who had reached the age at which iron-induced cardiac disease, the most common cause of death, usually occurs. Methods Using the duration of life without the need for either inotropic or antiarrhythmic drugs as a measure of survival without cardiac disease, we studied 97 patients born before 1976 who were treated with regular transfusions and chelation therapy. We used Cox proportional-hazards analysis to assess the effect of prognostic factors and life-table analysis to estimate freedom from cardiac disease over time. Results Of the 97 patients, 59 (61 percent) had no cardiac disease; 36 (37 percent) had cardiac disease, and 18 of them had died. Univariate analysis demonstrated that factors affecting cardiac disease-free survival were age at the start of che...

Efficacy of deferoxamine in preventing complications of iron overload in patients with thalassemia major.

Abstract: Background To determine whether deferoxamine prevents the complications of transfusional iron overload in thalassemia major, we evaluated 59 patients (30 were female and 29 male; age range, 7 to 31 years) periodically for 4 to 10 years or until death. Methods At each follow-up visit, we performed a detailed clinical and laboratory evaluation and measured hepatic iron stores with a noninvasive magnetic device. Results The body iron burden as assessed by magnetic measurement of hepatic iron stores was closely correlated (R = 0.89, P<0.001) with the ratio of cumulative transfusional iron load to cumulative deferoxamine use (expressed in millimoles of iron per kilogram of body weight, in relation to grams of deferoxamine per kilogram, transformed into the natural logarithm). Each increase of one unit in the natural logarithm of the ratio (transfusional iron load to deferoxamine use) was associated with an increased risk of impaired glucose tolerance (relative risk, 19.3; 95 percent confidence interval, 4.8 to...