Extramedullary hematopoiesis is associated with lower cardiac iron loading in chronically transfused thalassemia patients

Am J Hematol. 2015 Nov;90(11):1008-12. doi: 10.1002/ajh.24139. Epub 2015 Oct 8.

Abstract

The aim of this study was to evaluate, in a large cohort of chronically transfused patients, whether the presence of extramedullary hematopoiesis (EMH) accounts for the typical patterns of cardiac iron distribution and/or cardiac function parameters. We retrospectively selected 1,266 thalassemia major patients who had undergone regular transfusions (611 men and 655 women; mean age: 31.3 ± 8.9 years, range: 4.2-66.6 years) and were consecutively enrolled within the Myocardial Iron Overload in Thalassemia network. The presence of EMH was evaluated based on steady-state free precession sequences; cardiac and liver iron overloads were quantified using a multiecho T2* approach; cardiac function parameters and pulmonary diameter were quantified using the steady-state free precession sequences; and myocardial fibrosis was evaluated using the late gadolinium enhancement technique. EMH was detected in 167 (13.2%) patients. The EMH+ patients had significantly lower cardiac iron overload than that of the EMH- patients (P = 0.003). The patterns of cardiac iron distribution were significantly different in the EMH+ and EMH- patients (P < 0.0001), with a higher prevalence of patients with no myocardial iron overload and heterogeneous myocardial iron overload and no significant global heart iron in the EMH+ group EMH+ patients had a significantly higher left ventricle mass index (P = 0.001) and a significantly higher pulmonary artery diameter (P = 0.002). In conclusion, in regularly transfused thalassemia patients, EMH was common and was associated with a thalassemia intermedia-like pattern of cardiac iron deposition despite regular transfusion therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Female
  • Heart Ventricles / metabolism
  • Heart Ventricles / pathology
  • Hematopoiesis, Extramedullary*
  • Humans
  • Iron / metabolism*
  • Iron Overload / etiology
  • Iron Overload / metabolism*
  • Iron Overload / pathology
  • Liver / metabolism
  • Liver / pathology
  • Male
  • Middle Aged
  • Myocardium / metabolism*
  • Myocardium / pathology
  • Retrospective Studies
  • Transfusion Reaction*
  • beta-Thalassemia / metabolism*
  • beta-Thalassemia / pathology
  • beta-Thalassemia / therapy

Substances

  • Iron