Abstract
Accidental detachment of mechanical valve leaflet during implantation is a rare and potentially serious complication. When the lost leaflet cannot be found by direct visualisation, additional diagnostic procedures are necessary to detect it. Computer tomography is the best detection method, but the patient needs reoperation. We presented a patient in whom the detached leaflet migrated and became trapped into the left inferior pulmonary vein. The computed tomography (CT) scan was used to reveal leaflets, and successful extirpation was performed in the second operation.