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“Trust thyself: every heart vibrates to that iron string.” Ralph Waldo Emerson
According to WHO data, approximately 56 000 babies are born each year with thalassaemia major, including at least 30 000 who require lifelong transfusions to survive. Of those transfused, under 40% obtain adequate chelation therapy. An estimated 100 000 patients world wide are currently living with regular transfusions, but at least 3000 die each year in their teens or early 20s from uncontrolled iron overload, mainly due to heart failure. With no physiological excretory pathway, iron from transfused blood accumulates in the liver, heart, endocrine and other organs causing tissue damage and impairment in function. Chelating agents can remove the excess iron and prevent complications, the most serious of which is death from heart failure due to myocardial siderosis. Progressive cardiac iron loading eventually leads to left ventricular (LV) dilatation and reduction in LV ejection fraction but this is a late manifestation of severe myocardial siderosis and once clinical evidence of heart failure has developed, the prognosis is poor.
An important challenge is the non-invasive assessment of cardiac iron overload. Recent developments in cardiovascular magnetic resonance (CMR) have made it a valuable method for monitoring chelation therapy in patients at risk of transfusional iron overload, using magnetic resonance measurements of transverse relaxation,1 most importantly the “T2-star” (T2*) technique.2 T2* is a unique, quantifiable CMR parameter (measured in milliseconds) which is shortened in proportion to the level of particulate iron (in the form of haemosiderin) within myocardial cells. Although there are minor effects from deoxygenated blood and fibrosis, these are minimal in comparison with the effect of the iron at clinically relevant levels of myocardial iron overload.3 Low T2* values are associated with decreasing LV ejection fraction and an increased risk of developing heart failure as a result of …
Footnotes
Competing interests DJP, Novartis: consultancy, speakers honoraria, principal investigator of two Novartis studies (2409 and 2206), research funding; Siemens: consultancy, research funding; cardiovascular imaging solutions: equity ownership; ApoPharma: consultancy, speaker’s honoraria. J-PC has received speaker’s honoraria from Swedish Orphan International.
Provenance and Peer review Commissioned; not externally peer reviewed.