Pulmonary hypertension in β thalassaemia.

Pulmonary hypertension is one of the leading causes of morbidity and mortality in patients with haemolytic disorders and is a frequent finding in echocardiographic screening of patients with β thalassaemia. Substantial progress has been made in understanding of the multifactorial pathophysiology of pulmonary hypertension in β thalassaemia. Haemolysis, reduced nitric oxide bioavailability, iron overload, and hypercoagulopathy are among the main pathogenetic mechanisms. Various disease-directed therapeutic methods, such as transfusion, chelation, and splenectomy, have important roles in the development of pulmonary hypertension in β thalassaemia. Studies investigating the prevalence of pulmonary hypertension in β thalassaemia are mostly based on echocardiographic findings, and are thus limited by the scarcity of information derived from right heart catheterisation. Invasive pulmonary haemodynamic data are needed to clarify the true prevalence of pulmonary hypertension in β thalassaemia, to better understand the underlying pathophysiology and risk factors, and to define the optimum therapy for this devastating complication.