Long-term Extension, Multicentre, Multi-international Study to Evaluate the Safety and Tolerability of Oral BAY63-2521 (1mg, 1.5 mg, 2.0 mg, 2.5 mg Tid) in Patients With Chronic Thromboembolic Pulmonary Hypertension (CTEPH).

Patients who have completed the 16 weeks treatment of the CHEST-1 trial (study number 11348) will be asked to participate in this long term extension study with BAY63-2521. The aim of the long term study is to collect additional information to evaluate the safety and tolerability of BAY63-2521. Patients will be treated with open label medication on their individual optimal dose between 0,5 mg - 2,5 mg tid.