Background and aims

Patients with precapillary pulmonary hypertension (PH) due to pulmonary vascular disease (PVD) have reduced exercise capacity, limiting daily activity and quality of life. Phospodiesterase-5 inhibitors including sildenafil are used to treat PVD. This study examined effects of sildenafil on pulmonary hemodynamics during exercise in PVD.

Method

PVD-patients diagnosed as pulmonary arterial or chronic thromboembolic PH (PAH/CTEPH) underwent right heart catheterization assessed at rest and during mild exercise. Main outcomes were mean pulmonary artery pressure (mPAP), cardiac output (CO) and mPAP/CO-slope before and ?60?min after additive sildenafil (50?mg oral).

Results

22 PVD-patients (14 PAH, 8 CTEPH, 9 women, 15 pretreated (9 combination therapy)) with a mean±sd age 54±14?years, mPAP 39±10?mmHg, CO 4.7±1.5?l·min?1 and pulmonary vascular resistance 6.9±3.8 WU were included. After sildenafil, mPAP and CO at rest were unchanged, but at end-exercise, mPAP and mPAP/CO slope significantly decreased (mPAP 61±16 versus 54±16?mmHg; mean difference (95% CI) ?7 (?11 to ?4), p<0.001 and mPAP/CO-slope 9.8±4.9 versus 6.6±3.3; ?3(?4.9 to ?1.2) p=0.002).

The mean systemic arterial pressure was significantly lower after additive sildenafil at rest (?9 (?13 to ?5, p<0.001)) mmHg and at end-exercise (?9(?13 to ?5, p<0.001)) mmHg. One patient experienced dizziness.