HOW EFFECTIVE IS THE TREATMENT WITH HIGH-DOSE NIFEDIPINE FOR PRIMARY PULMONARY-HYPERTENSION

The efficacy of high-dose nifedipine in the treatment of primary pulmonary hypertension was determined in a nonrandomized, uncontrolled trial at a single referral center. Sixteen consecutive patients with primary pulmonary hypertension referred for evaluation of lung transplantation, were assessed for acute hemodynamic response to oral nifedipine (25 to 360 mg, mean 140 mg) during right heart catheterization. The acute vasodilator trial was terminated unsuccessfully in 13 patients. The causes were systemic hypotension or a decrease in the cardiac index in six patients or a lack of any substantial change in the pulmonary arterial pressure in seven patients. Only three patients had a clear acute response defined by a decrease in the mean pulmonary arterial pressure of 35.3 ± 8.1% and in the pulmonary vascular resistance of 55.0 ± 11.5%, and an increase in the cardiac index of 36.3 ± 26.0%. Despite long-term treatment with nifedipine, two of these patients developed right heart failure during the following 3 months, so that nifedipine had to be stopped. Only one patient experienced a sustained clinical and hemodynamic improvement. In this patient, echocardiography showed a reduction in the right ventricular hypertrophy after a follow-up of 9 months. High-dose nifedipine demonstrated a prolonged effect only in one of 16 patients with severe primary pulmonary hypertension.