Introduction and objective: Prostacyclin therapy is an effective treatment for severe pulmonary hypertension. Sildenafil, a selective phosphodiesterase type 5 inhibitor, induces selective vasodilatation of the pulmonary vessels. A synergistic effect has been described for these two drugs. The aim of this study was to evaluate the efficacy and safety of sildenafil as rescue therapy in patients with severe pulmonary hypertension on chronic treatment with prostacyclin whose clinical or functional course was unsatisfactory.
Patients and method: Observational study of 11 patients (7 men, 4 women, mean age 42  years) diagnosed as having severe idiopathic pulmonary hypertension, who were receiving chronic prostacyclin therapy. Sildenafil was started after a worsening of their clinical or functional status. Baseline, 3-month and 12-month follow-up evaluations were based on functional status (NYHA functional class and 6-minute walking test), the presence of decompensated right heart failure and echocardiogram.
Results: Seven of the 11 patients showed significant improvements in exercise capacity (distance walked in 6 minutes) at 3 (+25 m) and 12 months' follow-up (+36 m). Improvements in functional class were seen, and heart failure disappeared. No significant adverse effects of sildenafil were detected. The echocardiographic parameters showed a significant reduction in right ventricular end-diastolic diameter and left ventricular diastolic eccentricity index. One patient died after 4 months of follow-up from sudden cardiac death.
Conclusions: The addition of oral sildenafil to chronic prostacyclin treatment in patients with severe pulmonary hypertension improved functional capacity and reduced episodes of decompensated right heart failure, with good tolerance and no significant adverse effects.