Hemodynamic effects of nifedipine in pulmonary hypertension.

Nifedipine is a calcium antagonistic drug which reduces elevated vascular resistances. The hemodynamic effects of 20 mg of sublingual nifedipine were studied in 10 patients with chronic pulmonary hypertension. The etiology of pulmonary hypertension was chronic lung disease in 4, congenital heart disease in 2, mitral stenosis in 1, recurrent pulmonary embolism in 2 and primary pulmonary hypertension in one case. 30' after the drug administration there was a fall both of total pulmonary vascular resistance (from 992 +/- 586 to 648 +/- 428 d s cm-5, p less than 0.02) and of systemic vascular resistance (from 1416 +/- 868 to 896 +/- 440 d s cm-5 p less than 0.02) with an increase of systemic cardiac index from 3.2 +/- 1 to 4.5 +/- 2 l/min/m'2 (p less than 0.02). No significant change in systemic arterial oxygen saturation was noted, while pulmonary arterial oxygen saturation increased from 56 +/- 16 to 62 +/- 13% (p less than 0.01). These hemodynamic changes persisted for 120' when a significant fall of mean pulmonary arterial pressure was also noted (from 59 +/- 11 to 52 +/- 9 mm Hg, p less than 0.02). These data indicate that nifedipine may be useful to reduce pulmonary resistance in pulmonary hypertension. However this effect was less pronounced in patients with chronic lung disease compared to the other cases. It is suggested that the type of pulmonary arterial changes may determine the hemodynamic response. Nifedipine may be particularly indicated when vasoconstriction (as in primary pulmonary hypertension) is the main determinant of pulmonary hypertension.