To evaluate the effects of long-term intravenous infusion of prostacyclin on exercise capacity, hemodynamics, and survival in patients with primary pulmonary hypertension.

Open, multicenter, uncontrolled trial.

Four referral centers.

18 patients with primary pulmonary hypertension: 1 New York Heart Association (NYHA) class II patient, 13 NYHA class III patients, and 4 NYHA class IV patients.

Continuous intravenous prostacyclin administered by portable infusion pumps. All patients were treated with anticoagulant agents.

With the 6-minute walk used to evaluate exercise capacity, patients could walk on average more than 100 meters farther after prostacyclin therapy was initiated (distance at 6 months, 370 ± 119 meters compared with 264 ± 160 meters at baseline; P < 0.001; distance at 18 months, 408 ± 138 meters; P = 0.02 compared with baseline). Hemodynamics were improved at 6 months: The cardiac index increased 18% (95% CI, 0.1% to 36.7%; P = 0.02), and mean pulmonary artery pressure and total pulmonary resistance decreased 9% (CI, 1.4% to 15.7%; P = 0.03) and 26% (CI, 6.1% to 46.3%; P = 0.02), respectively, compared with baseline. The improvements in cardiac index and total pulmonary resistance were maintained at 12 months (27% increase [CI, 1.3% to 51.9%; P = 0.05] and 32% decrease [CI, 9.7% to 53.6%; P = 0.02] compared with baseline, respectively). Survival was improved in NYHA class III and IV patients who received continuous prostacyclin (n = 17; follow-up, 37 to 69 months) when compared with historical controls who received standard therapy (National Institutes of Health Primary Pulmonary Hypertension Registry, n = 31, P = 0.045). Kaplan-Meier estimates of 1-, 2-, and 3-year survival rates for the patients treated with prostacyclin were 86.9%, 72.4%, and 63.3%, respectively, compared with 77.4%, 51.6%, and 40.6% for the historical control group (hazard ratio, 2.9 [CI, 1.0 to 8.0; P = 0.045]). Serious complications attributable to the drug and delivery system included two deaths and seven episodes of nonfatal sepsis in three patients.

Continuous intravenous prostacyclin resulted in sustained clinical and hemodynamic improvement and probably in improved survival in patients with severe primary pulmonary hypertension. Despite potentially serious complications, long-term prostacyclin may be especially helpful in seriously ill patients awaiting transplantation.