A potential role for sildenafil in the management of pulmonary hypertension in patients with parenchymal lung disease

Sildenafil offers potential to treat patients with pulmonary hypertension by selectively inhibiting phosphodiesterase type five pathways in the lung. It is recommended for selected patients with pulmonary arterial hypertension, but its role in the management of pulmonary hypertension associated with parenchymal lung disease is unclear. Seven patients (68–86 years) with end stage chronic obstructive pulmonary disease (COPD, 4) and idiopathic pulmonary fibrosis (IPF, 3) were referred to our unit. All patients had a long-term history of chronic lung disease and were on maximal appropriate therapy prescribed by their referring pulmonologist. Thromboembolic disease was excluded by pulmonary angiography and all patients had had high resolution thoracic CT scan. At assessment right heart catheterisation, 2D echocardiography and 6-min walk test were performed prior to commencement of sildenafil 50 mg tds. Their medication was otherwise unchanged. After 8 weeks treatment, right heart catheterisation, 2D echocardiography and 6-min walk test were repeated. The pulmonary vascular resistance was reduced in six patients (from 13, 3, 3, 6.5, 3.5 and 10.5 wood units to 9.7, 2.5, 2.8, 4.4, 2.5 and 5.4 wood units, respectively). Six-minute walk test increased in six patients (from 110 m, 210 m, 80 m, 30 m, 210 m and 80 m to 130 m, 312 m, 120 m, 82 m, 244 m and 100 m, respectively). One patient with COPD did not demonstrate a favourable response although their cardiac output increased on sildenafil therapy. 2D echocardiography showed a reduction in estimated PA pressure in six patients with an improvement in right ventricular systolic function in two COPD patients. Our results suggest that sildenafil may have a role for selected patients with COPD and IPF who have pulmonary hypertension.