Sonographic diagnosis in iatrogenic entrapment of a femoropopliteal bypass graft

The success of duplex scanning has been well documented in many different vascular territories to diagnose arterial narrowing and occlusion. One area to which this technique has been best applied is the graft surveillance and early diagnosis of mechanical causes of graft failure. An uncommon cause of iatrogenic complication in femoropopliteal bypass grafting is popliteal artery entrapment syndrome (PAES). Developmentally, the gastrocnemius muscle arises from the calcaneus, migrating cephalad until it divides into lateral and medial heads. The lateral head attaches first to the lateral epicondyle of the femur, and the medial head attaches later to the medial epicondyle. At the time of the attachment of the medial head, the popliteal artery has already formed and is in its normal anatomic location. If the popliteal artery develops late or if the medial head migrates early, the artery is not in its normal location; instead, it is swept medially and impinged against the femur as the medial head attaches to the epicondyle. 1 A similar complication is seen when the graft is tunneled superficial to the medial head of the gastrocnemius muscle, leading to compression of the graft. 2,3 This case report describes the incidental finding of graft entrapment on angiography confirmed by duplex sonography, surgical treatment, and postoperative surveillance sonography.