Effect of nifedipine on hemodynamics in precapillary pulmonary hypertension at rest and during exertion

Abstract

The effect of sublingual nifedipine (20 mg) on haemodynamics at rest and during bicycle ergometry in supine position was assessed in 22 patients with precapillary pulmonary hypertension (obstructive form: n = 17, restrictive form: n = 2, combined obstructive-restrictive: n = 3). At rest nifedipine resulted in an increase of cardiac frequency from 85 to 89/min, during exercise from 109 to 120/min (P less than 0.05). Concomitantly the mean arterial blood pressure decreased significantly both at rest and during exercise. The mean pulmonary arterial pressure showed significant reduction from 42.9 to 36.2 mm Hg (P less than 0.0005) only during exercise. The total body vascular resistance at rest decreased by 21% (P less than 0.005), during exercise by 15% (P less than 0.1). Pulmonary arteriolar resistance at rest decreased by 9%, during maximum loading by 34% from 312 to 215 dyn X s X cm-5 (P less than 0.05). Nifedipine was shown to be a suitable agent for lowering right ventricular afterload in secondary pulmonary hypertension due to chronic lung disease. The beneficial effect at rest depends on the extent of the pulmonary arteriolar resistance and the mean pulmonary arterial pressure. However, during exercise conditions it can be observed in the majority of patients (93%). Due to the variable response haemodynamic assessment is required prior to routine use in order to establish patients with optimal response.