No clear increased risk from oral contraceptives

Premature death in patients with clinical evidence of severe right ventricular strain and no obvious predisposing condition has been recognised for over a century. In 1952 Paul Wood distinguished this syndrome of primary pulmonary hypertension from the pulmonary vascular disease that complicates some congenital heart lesions,1 recognising the very poor prognosis that continues to characterise this rare disorder. Its yearly incidence is between 1/200 000 and 1/1000 000, with the result that progress in understanding its pathology and interrupting its natural course has been slow. The overall mean survival remains under five years despite a variety of new treatments.

As in many systemic arterial diseases, there is increasing evidence that primary pulmonary hypertension is an endothelial disorder. The characteristic vascular obliteration that is observed as the condition progresses is thought to be the end stage of intense vasospasm and thrombosis, in different proportions in the predominantly “thromboembolic” and predominantly “plexogenic” histological types. The distinction between these as pathological or clinical entities is blurred, and it is likely that disruption of the antithrombotic and vasodilator functions of the pulmonary endothelium leads to irreversible structural pulmonary vascular disease. The endothelial products that are discussed most widely in this context are nitric oxide and prostacyclin, both of which are vasodilators …