<br>        Inclusion Criteria:<br><br>          -  Female and male patients, 18 years = age = 85 years<br><br>          -  Diagnosis of Pulmonary Hypertension Group 1 according to Nizza Definition (PAH)<br>             confirmed by invasive methods, WHO functional class II and III<br><br>          -  Existing clinical need to repeat a right ventricular catheter examination (as<br>             recommended by the current Kölner Konsensuskonferenz)<br><br>          -  Ability to understand study goals and agree to study participation<br><br>          -  Hemodynamic criteria of ventricular catheter examination:<br><br>               -  Pulmonary vascular resistance (PVR)> 240 dyn x sec x cm-5<br><br>               -  Mean Pulmonary Arterial Pressure (mPAP) = 25 mmHg<br><br>          -  Clinical need to receive treatment with a drug approved for the treatment of PAH for<br>             the first time<br><br>          -  Potentially fertile women must agree to use highly effective methods of contraception,<br>             either through abstinence or the use of at least two methods of contraception from the<br>             date of consent until one month after the end of the study. An effective pregnancy<br>             protection consists in the combination of a hormonal contraceptive (oral, injectable<br>             or implant) and a barrier method (condom or diaphragm with a vaginal spermicide)<br><br>          -  Written consent to the clinical trial<br><br>        Exclusion Criteria:<br><br>        Existing therapy with positive inotropic drugs such as Catecholamines (including<br>        norepinephrine, dobutamine, suprarenin)<br><br>          -  Pregnancy or breastfeeding<br><br>          -  General contraindication for examinations to be performed during the study<br><br>          -  Hypersensitivity to the active substances or to a constituent of the study medication<br>             (in particular lactose and soya)<br><br>          -  Simultaneous participation in another medical therapy study<br><br>          -  Simultaneous participation in another non-drug study that would preclude participation<br>             in this study<br><br>          -  Participation within one month after completing another therapy study<br><br>          -  Heavy liver function disorders<br><br>          -  Existing increase in liver aminotransferases (aspartate aminotransferase (AST) and /<br>             or alanine aminotransferase (ALT))> 3 × ULN<br><br>          -  Systolic blood pressure <95 mmHg<br><br>          -  Pulmonary hypertension associated with idiopathic interstitial pneumonia (PH-IIP)<br><br>          -  anemia (Hb <10 g / dl)<br><br>          -  Concomitant medication with potential interaction to macitentan and/or riociguat<br>             according to the IB<br><br>          -  Severe kidney dysfunction<br><br>          -  Severe hemoptysis<br><br>          -  History of bronchial artery embolization<br><br>          -  smoker<br>