Sildenafil treatment in COPD does not affect stroke volume or exercise capacity

In chronic obstructive pulmonary disease (COPD) patients, stroke volume response to exercise is impaired. The aim of the present study was to investigate whether 3 months of sildenafil treatment improves stroke volume and, if so, whether this improvement is related to the pulmonary artery pressure and translated into an improved exercise capacity. A total of 15 stable COPD patients (Global Initiative for Chronic Obstructive Lung Disease stage II-IV) underwent right heart catheterisation at rest and during exercise. Stroke volume was assessed by magnetic resonance imaging (MRI) at rest and during submaximal exercise in the supine position and compared with eight age-matched controls. Additionally, a cardiopulmonary exercise test and a 6-min walking distance test were performed. Exercise tests and MRI were repeated after 12 weeks of oral therapy with 50 mg sildenafil three times daily. Stroke volume in COPD patients was significantly lower than in healthy controls (62 +/- 12 versus 81 +/- 22 mL at rest and 70 +/- 15 versus 101 +/- 28 mL during exercise). Pulmonary hypertension (PH) was diagnosed in nine patients and was absent in six. Treatment with sildenafil had no effect on stroke volume or exercise capacity. Although the stroke volume was lower in COPD patients with associated PH in comparison with non-PH patients, there was no difference in treatment response between both groups. In the present group of 15 chronic obstructive pulmonary disease patients, a reduced stroke volume was found at rest and during exercise. Neither stroke volume nor exercise capacity were improved by 3 months of sildenafil therapy.