Effect of indomethacin on pulmonary vasomotor response in patients with mitral stenosis.

In 10 patients with mitral stenosis, ingestion of 125 mg indomethacin over a 24-h period had no effect on the elevated pressure in pulmonary artery. It did, however, in all patients, slightly potentiate a fall in pulmonary pressure induced by breathing of 100% oxygen. The results do not suggest that a prostaglandin mechanism is involved in chronic pulmonary vasoconstriction or that this mechanism is responsible for acute vasodilatation of the pulmonary bed induced by oxygen inhalation.