Pulmonary arterial hypertension (PAH) is a life threatening condition characterised by progressive obliteration of the small pulmonary arteries leading to increased pulmonary arterial resistance and right heart failure. Treatment for PAH has developed in the last few years since the description of new pathways related to the disease.¹ Recently, short term (6 months) use of imatinib, a platelet derived growth factor (PDGF) receptor antagonist, in combination with maximal PAH treatment (prostacyclin derivative, endothelin receptor antagonist, and type 5 phosphodiesterase inhibitor) has been shown to improve the haemodynamics and functional capacity in a single case of severe PAH.² We here report the first two cases of the long term (3 years or more) use of imatinib, as monotherapy or in combination with bosentan, a dual endothelin receptor antagonist. …