RESULTS: Of the 8 patients agreed for CGFB, 3 were men and 5 were women. The mean age of the patients was 52.4 years (range, 32-75 years). The thrombus-like mass occluded the central pulmonary arteries in all of the 8 patients. 3 occluded the right pulmonary artery, 2 in the left pulmonary artery and 2 located both in the pulmonary artery trunk and right pulmonary artery. Lung involvement was also identified in 3 patients. All the 8 patients were performed CGFB successfully and tissue samples were gained for histological examination. PAS was confirmed in 5 patients. CTEPH was considered the correct diagnosis with the histological findings from CGFB and confirmed after pulmonary thrombendarterectomy. While in 2 patients there were only necrotic tissue and thrombus detected from the harvested sample, one of the patients was then confirmed PAS with CT guided percutaneous lung biopsy 4 months later. All the 8 patients tolerated the procedure well. No complications like bleeding, perforation, etc. during and after CGFB in 8 patients.