Study objectives: To determine whether long-term IV prostacyclin (PGI2) use improves exercise capacity in patients with primary pulmonary hypertension (PPH). Design: Cycle ergometry and the 6-min walk was used to evaluate the exercise performance of patients with PPH. The patients underwent serial exercise testing after starting continuous IV PGI2 and were followed up for 19.5 ± 7.5 months. Peak work, peak oxygen consumption (V̇O2), peak O2 pulse, and distance walked in 6 min were used to evaluate performance. Background: PPH is characterized by medial hypertrophy and intimal proliferation of the pulmonary arterioles, leading to elevation of pulmonary artery pressure, right ventricular failure, and death. Palliative treatment consists of vasodilators, anticoagulants, cardiac glycosides, diuretics, and transplantation. PGI2, a potent vasodilator and inhibitor of platelet aggregation, has been used for long-term treatment when conventional therapy has been unsuccessful. Patients: Sixteen patients with PPH (10 women, 6 men; mean age, 24 years). Results: At the initiation of PGI2, peak work (± SD) was 35.5 ± 11% of predicted; peak V̇O2, 39 ± 10.4%; peak O2 pulse, 5.0 ± 1.7 mL/min; and distance on the 6-min walk, 428 ± 78 feet. At 18 to 27 months, peak work increased to 58.8 ± 23% of predicted (p = 0.001), peak V̇O2 increased to 52 ± 15% of predicted (p = 0.02), peak O2 pulse increased to 7.1 ± 3.0 mL/beat (p = 0.004), and performance on the 6-min walk increased to 526 ± 62 feet (p = 0.001). There was a positive correlation between peak V̇O2 and peak 6-min walk of 0.6 (p < 0.005) and between peak work and peak 6-min walk of 0.6 (p < 0.005). Conclusions: Exercise capacity improved in our patients at up to 27 months of follow-up. Exercise testing is helpful in assessing the functional capacity of patients with PPH and may be useful in guiding therapy. Patients who deteriorate while receiving optimal conventional therapy should be considered for IV PGI2 therapy.
- Exercise testing
- Primary pulmonary hypertension
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine
- Cardiology and Cardiovascular Medicine