Pulmonary hypertension in beta-thalassemia.
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.
Aessopos
Athanasios
A
First Department of Internal Medicine, University of Athens Medical School, Laiko General Hospital, 17 Aghiou Thoma St., Athens 115 27, Greece. aaisopos@cc.uoa.gr
Farmakis
Dimitrios
D
D000328:Adult; D000367:Age Factors; D001803:Blood Transfusion; D002302:Cardiac Output; D015913:Chelation Therapy; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology* / Q000503:physiopathology; D000860:Hypoxia / Q000209:etiology / Q000503:physiopathology; D019190:Iron Overload / Q000209:etiology / Q000503:physiopathology; D008875:Middle Aged; D013923:Thromboembolism / Q000209:etiology / Q000503:physiopathology; D014655:Vascular Resistance; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000503:physiopathology; D017086:beta-Thalassemia / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology / Q000628:therapy