A Long-term Extension Study of Riociguat in Patients With Symptomatic Pulmonary Arterial Hypertension.

Inclusion Criteria:

• Patients diagnosed with Pulmonary Arterial Hypertension (PAH) participating orhaving participated in the Bayer-sponsored studies 12935, 16719 or 18588, who havecompleted the main study phase and are still being treated with riociguat (eitherwhile still being on treatment with the respective study drug or by commercial meanswith Adempas) and who, in the opinion of the investigator, are expected to continueto have an overall positive benefit/risk from continuing treatment.

• Women and men of reproductive potential must agree to use adequate contraceptionwhen sexually active. This applies for the time period between signing of theinformed consent form and 30 days after the last administration of study drug.

Exclusion Criteria:

• Ongoing serious adverse event (SAE) from originating study that is assessed asrelated to riociguat

• Pregnant women or breast-feeding women

• Any contra-indication to Adempas treatment listed in the BAY63-2521 / RiociguatInvestigators's Brochure

• Concomitant participation in another clinical study with the study drug

• Patients with pulmonary hypertension associated with idiopathic interstitialpneumonia (PH-IIP)