Iron deficiency is known to be common and detrimental in chronic left
heart failure, where parenteral
iron treatment has been shown to improve exercise capacity, New York Heart Association functional class and patient wellbeing. There is now increasing interest in the role of
iron in the natural history of
pulmonary arterial hypertension (PAH).
Iron availability influences the pulmonary
vasoconstrictor response to
hypoxia and accumulating evidence indicates that
iron deficiency is prevalent in idiopathic and heritable forms of PAH,
iron status being related to exercise capacity, symptoms and poorer survival in patients with idiopathic PAH (IPAH). Potential mechanisms behind
iron deficiency in IPAH include inhibition of
dietary iron uptake by the master
iron regulator
hepcidin. High
hepcidin levels underlie the anaemia of
chronic disease. Possible stimuli of the observed high levels of
hepcidin in IPAH include dysfunctional
bone morphogenetic protein receptor type II signalling and
inflammation.
Iron status may influence outcomes through modulation of the pulmonary circulation as well as myocardial and skeletal muscle function. Two parallel studies, from our centre (Hammersmith Hospital, London, UK) and others in the UK and Amsterdam (the Netherlands), investigating the safety and potential benefit of
iron supplementation in patients with PAH are currently under way.