Comparative study of acute and chronic effects of nifedipine in patients with secondary pulmonary hypertension

The effects of nifedipine in a single dose of 10 mg on the pulmonary circulation and the selected right and left ventricular function indices were studied in a group of 10 patients with secondary pulmonary hypertension (mean systolic pressure 55.2 mm Hg). In 8 patients hemodynamic studies were repeated after seven days treatment (3 x 10 mg). Acute treatment with nifedipine resulted in a reduction in mean systolic arterial pressure by 21.8%, diastolic by 12.2% and systemic resistance by 25.5%, and in an increase in cardiac index by 14.3%. After 7 days a similar pattern of changes was observed, however with less intensity: systolic pressure was reduced by 10.3% diastolic by 5.5%, and systemic resistance by 17.1%. Pulmonary artery wedge pressure did not change after a single dose, and mean pulmonary artery pressures showed a tendency toward lower levels: systolic by 8.9% and diastolic by 8.6%, whereas total pulmonary resistance decreased markedly (by 22.7%), as well as pulmonary vascular resistance. Right ventricular filling pressure was reduced. After chronic treatment we found a further slight fall in the pulmonary arterial pressure. Although per cent changes were similar to those in the arterial pressure, alterations in the mean values were not statistically significant. The total pulmonary resistance remained reduced. While analysing the changes in the pulmonary circulation and right ventricular indices it should be noted that they were less intense and less homogeneous than the left ventricular function parameters. Some of the patients showed certain similarities in the direction and intensity of changes in the hemodynamic indices of the pulmonary circulation in the acute and chronic experiment.