oral Sildenafil 20 mg three times a day for 90 days

oral Sildenafil 3 x 20 mg for 90 days

Right heart catheterisation with comprehensive hemodynamic measurements (pressures in RA, RV, PA, PCW position; cardiac index (CI) by thermodilution; oxygen saturation in the PA; the same under exercise conditions) is performed. In case of precapillary pulmonary hypertension, Sildenafil is given I.V. and acute tolerability, safety and efficacy on hemodynamic parameters are registrated. Successful vasoreactivity testing is defined by lowering the mean PA pressure by 10 mmHg or more, lowering it below 40 mmHg and maintaining / rising of the CI. Safety is mainly defined by lack of a substantial effect of the study drug on systemic blood pressure.

Complete hemodynamic and functional assessment after 90 days of oral Sildenafil therapy (same protocol as before except vasoreactivity testing). Hemodynamic parameters which characterize successful oral therapy are mainly mean PA-pressure (decrease), pulmonary vascular resistance (decrease) and cardiac index (increase) - at rest and exercise.

Functional improvement is further characterized by exercise capacity (cardiopulmonary exercise testing: improvement of V´O2 peak by ≥ 1 ml/min/kg), fall of NTproBNP, improvement of echocardiographic parameters of right ventricular function (TAPSE, S´, RV-FAC).

Evaluation, if positive initial vasoreactivity testing results in successful oral therapy as defined above.