Due to severe RV heart failure, the patient was transferred to the operating room where he suddenly developed cardiac arrest. CPR, median sternotomy, and cardiopulmonary bypass were initiated urgently. The right atrium and MPA were opened, and embolectomy was performed. Because of the extensions of the clots into the distal pulmonary arteries and the impression of the surgeon that he could not reach distally located clots, a flexible fiber-optic cystoscope was inserted from the MPA into the tertiary pulmonary arteries. The fiber-optic direct visualization technique allowed the surgeon to differentiate organized emboli (Fig 1C), which could not be extracted safely using a blind procedure from more acute emboli (Figs 1A, 1B, 1D). Nonorganized emboli were visualized and extracted using saline injection and suction. Organized emboli required a Fogarty catheter; one or two attempts were required for each embolus removal. Overall, seven clots were removed. The procedure took about 15 min. Prior to chest closure, additional angioscopic visualization was performed, with no residual clots visualized (Figs 1E, 1F). The total duration of the surgery was 100 min.