[Natural history of primary pulmonary hypertension elucidated by pulmonary hemodynamics].

The present study was undertaken to clarify the natural history of primary pulmonary hypertension (PPH) from a hemodynamic point of view. The subjects consisted of 83 patients (18 men and 65 women), whose ages ranged from 14 to 69 years and averaged 33 years. They were contacted through a nationwide survey. All patients underwent right-sided cardiac catheterization; cardiac output was measured in 52 patients and pulmonary capillary wedge pressure, in 40 patients. The following results were obtained. 1. The patients who died within three months of their cardiac catheterization were in severe right ventricular failure as shown by their elevated right atrial pressures and decreased cardiac indices. 2. The patients who died suddenly within two years of their cardiac catheterization had the same degree of right ventricular failure. The only difference was severe hypoxia in the patients with cardiac failure (54 +/- 21 vs 66 +/- 4 mmHg, p less than 0.05). 3. The patients who survived more than two years had normal right ventricular function. 4. Among the hemodynamic variables used to estimate prognosis; namely, pulmonary artery diastolic pressure, pulmonary capillary wedge pressure, cardiac index, pulmonary vascular resistance and pulmonary to systemic vascular resistance ratio, the cardiac index was the best predictor of prognosis.