Background: Pulmonary thromboendarterectomy may be a cure for patients with chronic thromboembolic pulmonary hypertension (CTEPH) with proximal obstruction. Conversely, short-term prognosis is poor for inoperable CTEPH patients with distal obstruction. Vascular remodeling lesions can be found in lungs of patients with CTEPH. Little is known about epoprostenol therapy in inoperable distal CTEPH patients.
Methods: We conducted a retrospective analysis of 27 consecutive patients with inoperable distal CTEPH, who were in New York Heart Association Functional Class (NYHA FC) III (n = 20) or IV (n = 7) and treated with long-term intravenous epoprostenol.
Results: Before epoprostenol initiation (baseline), 6-minute walk distance (6MWD) was 265 +/- 117 m, right atrial pressure 13 +/- 5 mm Hg, mean pulmonary artery pressure (mPAP) 56 +/- 9 mm Hg, cardiac index (CI) 1.9 +/- 0.3 liters/min/m2, total pulmonary resistance (TPR) 29.3 +/- 7.0 U/m2 and mixed venous oxygen saturation 52 +/- 8%. After 3 months of epoprostenol (n = 23; mean epoprostenol dose 16 +/- 2 ng/kg/min), NYHA FC improved by one class in 11 of 23 patients, 6MWD increased by 66 m (p < 0.0001), and hemodynamics also improved (mPAP: 51 +/- 8 mm Hg, p = 0.001; CI: 2.3 +/- 0.4 liters/min/m2, p = 0.0003; TPR: 23.0 +/- 5.0 U/m2, p < 0.0001). At last evaluation (n = 18; 20 +/- 8 months), mean dose of epoprostenol was 30 +/- 8 ng/kg/min, NYHA FC was improved in 9 of 18 patients and there was sustained improvement in 6MWD (+46 m, p = 0.03) and hemodynamic parameters. Survival at 1, 2 and 3 years was 73%, 59% and 41%, respectively.
Conclusions: Long-term treatment with intravenous epoprostenol improves exercise capacity and hemodynamic parameters in patients with inoperable distal CTEPH. Epoprostenol may be used as bridge therapy in CTEPH patients awaiting lung transplantation.