[Etiopathogenic and clinical considerations on primary pulmonary hypertension].
Primary pulmonary hypertension is a severe condition of unknown etiology first described by Romberg in 1891. The authors review the literature with particular emphasis on new hypotheses concerning etiopathogenesis, and recent suggestions for management. The former take into account the discovery of endothelium derived relaxing factors and the identification in pulmonary arteries of a polypeptide called endothelin. Further hypotheses contemplate 1) interaction between platelets and endothelium; 2) the role of heparin-inhibiting enzymes; 3) abnormal cellular adhesion. Heart catheterism is apt to exclude other causes of pulmonary hypertension and also permits to assess the severity of the condition and its prognosis, as well as acting as a guide to management. If venous O2 saturation is higher than 63%, calcium blocking agents and anticoagulants should be used, if it is lower than 63% long-term prostaglandin infusion should be given awaiting heart-lung transplantation unless this can be done immediately.