Effect of external pressure on axillofemoral bypass grafts.

External compression of axillofemoral grafts has been suggested many times as a cause for graft thrombosis. Thrombosis during sleep is the most common presentation of axillofemoral graft failure. Therefore, external compression of the graft by the body weight has been implicated in graft thrombosis. Six consecutive patients with axillofemoral bypass grafts for aortoiliac disease were studied on routine clinic visits. Pulsatile flow characteristics were studied by pulse volume recordings (PVR) and segmental Doppler pressure measurements in calf and ankle, prior to and during attempted graft compression, by having the patient lay on the graft. External compression by body weight did not alter the PVR and segmental Doppler pressure (P = NS) in the distal circulation. Therefore, these data suggest that external compression by the body weight may not be the primary cause of graft failure.