Sildenafil improves hemodynamic parameters in COPD—an investigation of six patients

Pulmonary hypertension (PH) is an important predictor of mortality in chronic obstructive pulmonary disease (COPD). The phosphodiesterase 5 inhibitor sildenafil has been demonstrated to reduce pulmonary arterial pressure (PAP) in different diseases. We wanted to investigate the effect of sildenafil on hemodynamic parameters and the 6-min walk test (6 MWT) in six patients with severe COPD and echocardiographically estimated PH. A 6 MWT was performed and hemodynamic parameters were measured by right heart catheterization before and 1 and 12 h after injection of 50 mg sildenafil intravenously. A 3-months period of peroral sildenafil therapy 50 mg twice daily followed and finally hemodynamic parameters and a 6 MWT were repeated. Intravenously applied sildenafil could be demonstrated to reduce PAP and pulmonary vasculature resistance (PVR) significantly. And after 3 months of oral sildenafil, the mean PAP has decreased from 30.2±5.5 mmHg (range: 24–39 mmHg) to 24.6±4.2 mmHg (range: 20–30 mmHg) (p=0.01p=0.01). The PVR has decreased from 401±108 dyn s cm−5 (range: 266–558 dyn s cm−5) to 264±52 dyn s cm−5 (range: 204–333 dyn s cm−5) (p<0.05p<0.05). Physical conditions improved: the 6-min walk distance increased from 351±49 to 433±52 m. In conclusion, in six patients suffering from severe COPD we could demonstrate significantly improved hemodynamic parameters after 50 mg sildenafil intravenous application. And after 3 months of oral sildenafil, walking distance in the 6 MWT increased significantly as well as hemodynamic parameters in the five patients who had accepted a second right heart catheterization.