Hemodynamic effect of hydralazine in advanced, stable chronic obstructive pulmonary disease with cor pulmonale. Immediate and short-term evaluation at rest and during exercise.

Hydralazine was administered to eight patients (mean age, 69 +/- 2 years) who had stable, advanced chronic obstructive pulmonary disease (COPD), pulmonary arterial hypertension (mean pulmonary arterial pressure, 31 +/- 3 mm Hg), and cor pulmonale. All of the patients were studied at rest and during exercise. After intravenous administration of hydralazine at rest, there were statistically significant increases in pulmonary arterial pressure (p less than 0.05), cardiac index (p less than 0.005), arterial oxygen saturation (p less than 0.01), and mixed venous saturation (SvO2) (p less than 0.005). Pulmonary vascular resistance did not change, and systemic resistance decreased (p less than 0.005). During exercise, pulmonary arterial pressure increased in all patients, and this increase was not blunted by hydralazine; however, cardiac index (p less than 0.005), arterial oxygen pressure (p less than 0.005), and SvO2 (p less than 0.001) increased further during exercise. The increase in pulmonary vascular resistance was significantly blunted by hydralazine (p less than 0.005). Therapy with the drug was continued orally in seven patients because one patient showed a deleterious response in pulmonary hemodynamics. After seven days of oral hydralazine, pulmonary arterial pressure and pulmonary vascular resistance were not statistically different from control. There were statistically significant increases in cardiac index (p less than 0.005) and SvO2 (p less than 0.05), systemic resistance decreased (p less than 0.01). The same condition was found during exercise; however, only two patients showed pulmonary gas exchange and pulmonary hemodynamic benefit at rest and during exercise with hydralazine therapy. Our results suggest that it is unlikely that vasodilator therapy with hydralazine will be useful in patients with advanced stable COPD and cor pulmonale who seem to have fixed pulmonary vascular disease.