Bosentan therapy for pulmonary arterial hypertension associated with hereditary haemorrhagic telangiectasia.

Hereditary haemorrhagic telangiectasia (HHT) is a disorder of arteriovenous malformations and telangiectases. In rare cases affected individuals may develop typical pulmonary arterial hypertension (PAH). Vasodilator therapy has not been recommended because of a potential increase in arteriovenous shunt volume. This report is on two patients with severe HHT-associated PAH who were treated with bosentan, an oral endothelin ET(A)/ET(B) receptor antagonist. After 1 year, symptomatic and functional improvements were confirmed by haemodynamic evaluation demonstrating a significant decrease of mean pulmonary artery pressures and an increase in cardiac index, without evidence for an increase in effective shunt volume.