Pulmonary vasodilator therapy for chronic obstructive pulmonary disease and cor pulmonale. Treatment with nifedipine, nitroglycerin, and oxygen.

The present study was undertaken to evaluate the short-term effects of nitroglycerin, nifedipine, and supplemental oxygen on hemodynamics and gas exchange in 11 patients in stable condition with chronic obstructive pulmonary disease and cor pulmonale. In general, both intravenous nitroglycerin and sublingual nifedipine significantly reduced the pulmonary vascular resistance index. For the group as a whole, nifedipine decreased the pulmonary vascular resistance index by significantly increasing the cardiac index, with minimal reductions in mean pulmonary arterial pressure. Conversely, nitroglycerin decreased the pulmonary vascular resistance index by markedly reducing the mean pulmonary arterial pressure but also decreased the cardiac index in some patients. Nitroglycerin also caused a significant decrease in mixed venous oxygen tension. Administration of oxygen did not cause any clinically significant improvement in resting hemodynamics following short-term administration. During the follow-up period, eight of 11 patients who were treated with pulmonary vasodilators in addition to long-term therapy with low-flow oxygen died within a mean of six months. This rate of survival was not significantly different than an age-matched and sex-matched control group with similar severity of disease who received only long-term therapy with low-flow oxygen. Based on these data, it seems unlikely that a substantial increase in survival will be obtained by combining pulmonary vasodilators with long-term oxygen therapy in patients with stable emphysema who have cor pulmonale and carbon dioxide retention.