Long-term treatment with sildenafil in chronic thromboembolic pulmonary hypertension

Abstract

For chronic thromboembolic pulmonary hypertension not amenable to pulmonary endarterectomy, effective medical therapy is desired.In an open-label uncontrolled clinical trial, 104 patients (mean±semage 62±11 yrs) with inoperable chronic thromboembolic pulmonary hypertension were treated with 50 mg sildenafilt.i.d.At baseline, patients had severe pulmonary hypertension (pulmonary vascular resistance 863±38 dyn·s·cm⁻⁵) and a 6-min walking distance of 310±11 m. Eight patients were in World Health Organization functional class II, 76 in class III and 20 in class IV.After 3 months’ treatment, there was significant haemodynamic improvement, with reduction of pulmonary vascular resistance to 759±62 dyn·s·cm⁻⁵. The 6-min walking distance increased significantly to 361±15 m after 3 months’ treatment, and to 366±18 m after 12 months’ treatment. A subset of 67 patients received a single dose of 50 mg sildenafil during initial right heart catheterisation. The acute haemodynamic effect of this was not predictive of long-term outcome.In this large series of patients with inoperable chronic thromboembolic pulmonary hypertension, open-label treatment with sildenafil led to significant long-term functional improvement. The acute effect of sildenafil may not predict the long-term outcome of therapy.