We report three cases with amalgamation of pulmonary thromboembolism after operation. Screening before operation for the deep vein thrombosis which causes pulmonary thromboembolism was important. In this study deep vein thrombosis was screened by ultrasonography, but pulmonary thromboembolism was not experienced. We therefore concluded that screening for deep vein thrombosis by ultrasonography is useful for patients with a high risk of developing this disease.
