NPPB and chronic thromboembolic pulmonary hypertension: The functional class NYHA at diagnosis resulted more frequently in III-IV and this underlines the literature data; probably due to the long median interval of time often required for diagnosis, approximately 70% of patients with CTEPH showed signs of right heart failure, hypoxemia or hypocapnic respiratory failure and elevated plasma BNP values [2,3,4,69,70,71,72,73].