This is an exciting time to be in pulmonary hypertension research. The past few years have witnessed a steady flow of publications documenting the beneficial effects of prostacyclin treatment in primary pulmonary hypertension (PPH) and other forms of pulmonary arterial hypertension and the emergence of new drugs with therapeutic possibilities in these conditions. More recently, genetic analysis of familial PPH has identified a molecular mechanism that opens up new opportunities for pharmacological intervention in this disease.

Untreated PPH has an appalling prognosis, with a median survival of 2.5 years. Both warfarin and calcium antagonists (for those who can tolerate them) improve survival but the most significant development in the treatment of PPH to date has been the use of intravenous prostacyclin and prostacylin analogues. Introduced initially as a bridge to transplantation, the shortage of suitable donors meant that many patients remained on treatment for several years. Controlled clinical trials have demonstrated that prostacyclin infusion improves exercise tolerance and pulmonary haemodynamics in both PPH1 and pulmonary hypertension secondary to scleroderma.2 Indeed, prostacyclin treatment may now be considered superior to lung transplantation in improving the quality of life and survival in such patients.3 Furthermore, the benefit of this treatment is also observed in patients with no acute vasodilator response to the drug, suggesting that in addition to vasorelaxation and its antiplatelet effects, prostacyclin may inhibit vascular remodelling.4 Although inhibition or reversal of vascular remodelling remains to be demonstrated clinically, studies with human pulmonary smooth muscle cells in vitro show that prostacyclin analogues inhibit growth, and that this effect is most evident in cells derived from the distal pulmonary vascular bed.5

Intravenous prostacyclin is now established as a treatment to be considered for all patients with PPH …