Objective: To explore the safety and efficacy of oral sildenafil therapy for pulmonary arterial hypertension (PAH), and to provide evidence for sildenafil treatment for Chinese patients with PAH.
Methods: In this 12-week, prospective, open-label, uncontrolled study, 56 patients with PAH were given oral sildenafil (25 mg, tid). The primary end point was change from baseline to 12 weeks in exercise capacity assessed by 6 min walk (6MW) test. Secondary end points included changes in WHO class and cardiopulmonary hemodynamics. Clinical worsening was defined as death, transplantation, hospitalization for PAH, or initiation of additional therapies for PAH, such as intravenous epoprostenol or oral bosentan.
Results: After 12 weeks, the compliance was good in 56 patients. Significant improvement was seen in NYHA heart function class and WHO class as compared to baseline (P < 0.01): from class IV to class III in 2, from class III to class II in 8 and to class I in 2 cases, and from class II to class I in 5 cases. No NYHA heart function class and WHO PAH function class deterioration were observed. Oral sildenafil increased 6MW distance, from (352 ± 80) m to (396 ± 78) m, with a change of (44 ± 70) m (P < 0.01). Significant improvement was seen in hemodynamics (mean pulmonary artery pressure, P < 0.01; cardiac index, P < 0.01; pulmonary vascular resistance, P < 0.01) at week 12 as compared with baseline. Mean right atrial pressure decreased (3 ± 11) mm Hg (1 mm Hg = 0.133 kPa), mean pulmonary arterial pressure decreased (6 ± 14) mm Hg, cardiac output increased (1.1 ± 2.0) L/min, cardiac index increased (0.7 ± 1.1) L×min(-1)×m(-2), and total pulmonary resistance decreased (490 ± 831) Dys×s×cm(-5). Side effects were mild and consistent with those reported with sildenafil treatment. No statistically significant clinical worsening was observed with sildenafil therapy for PAH patients.
Conclusions: Sildenafil improves exercise capacity, WHO functional class, and hemodynamics in patients with pulmonary arterial hypertension.