title: On improvement in ejection fraction with iron chelation in thalassemia major and the risk of future heart failure.
abstract: BACKGROUND
  Trials of iron chelator regimens have increased the treatment options for cardiac siderosis in beta-thalassemia major (TM) patients. Treatment effects with improved left ventricular (LV) ejection fraction (EF) have been observed in patients without overt heart failure, but it is unclear whether these changes are clinically meaningful.
  
  
  METHODS
  This retrospective study of a UK database of TM patients modelled the change in EF between serial scans measured by cardiovascular magnetic resonance (CMR) to the relative risk (RR) of future development of heart failure over 1 year. Patients were divided into 2 strata by baseline LVEF of 56-62% (below normal for TM) and 63-70% (lower half of the normal range for TM).
  
  
  RESULTS
  A total of 315 patients with 754 CMR scans were analyzed. A 1% absolute increase in EF from baseline was associated with a statistically significant reduction in the risk of future development of heart failure for both the lower EF stratum (EF 56-62%, RR 0.818, p < 0.001) and the higher EF stratum (EF 63-70%, RR 0.893 p = 0.001).
  
  
  CONCLUSIONS
  These data show that during treatment with iron chelators for cardiac siderosis, small increases in LVEF in TM patients are associated with a significantly reduced risk of the development of heart failure. Thus the iron chelator induced improvements in LVEF of 2.6% to 3.1% that have been observed in randomized controlled trials, are associated with risk reductions of 25.5% to 46.4% for the development of heart failure over 12 months, which is clinically meaningful. In cardiac iron overload, heart mitochondrial dysfunction and its relief by iron chelation may underlie the changes in LV function.
authors.affiliation: Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London UK. d.pennell@ic.ac.uk
authors.forename: D J
authors.initials: DJ
authors.lastname: Pennell
authors.forename: J P
authors.initials: JP
authors.lastname: Carpenter
authors.forename: M
authors.initials: M
authors.lastname: Roughton
authors.forename: Zi
authors.initials: Z
authors.lastname: Cabantchik
mesh_terms: D000293:Adolescent; D000328:Adult; D009202:Cardiomyopathies / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D007502:Iron Chelating Agents / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume / Q000187:drug effects; D013997:Time Factors; D016896:Treatment Outcome; D006113:United Kingdom; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D016277:Ventricular Function, Left / Q000187:drug effects*; D055815:Young Adult; D017086:beta-Thalassemia / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D007502:Iron Chelating Agents