This study was undertaken to evaluate the ability of intraoperative duplex scanning during infrainguinal vein bypass to identify technical abnormalities and to determine the relation between intraoperative scan result and early primary graft patency. We retrospectively reviewed of 78 consecutive intraoperative duplex scans for infrainguinal vein bypass that were performed between October 1993 and October 1996 during the course of infrainguinal vein bypass. Duplex scans were classified as normal or abnormal based on B-mode image and/or Doppler velocity spectra. Grafts were grouped according to duplex findings and intraoperative action: group I, normal intraoperative scan; group II, abnormal intraoperative scan, revised; group III, abnormal intraoperative scan, not revised. The relationship of intraoperative duplex scan findings to intraoperative graft revision to 1-month and 6-month primary graft patency by life table was analyzed. The analysis demonstrates that the results of intraoperative duplex scans can be used to identify grafts at low risk for early postoperative graft failure (groups I and II), and those at high risk for early postoperative graft failure (group III).