NATURE AND MANAGEMENT OF DUPLEX ABNORMALITIES ENCOUNTERED DURING INFRAINGUINAL VEIN BYPASS-GRAFTING

Purpose: This study was undertaken to evaluate the application of dupl ex scanning during infrainguinal vein grafting procedures to verify ve in conduit preparation, anastomotic patency, and graft hemodynamics. M ethods: Between 1991 and 1995, 275 infrainguinal vein bypasses (in sit u, 114; reversed, 82; nonreversed translocated, 48; spliced alternativ e/arm vein, 31) to the popliteal (n = 116) or an infrageniculate arter y (n = 159) were scanned during surgery for sites of color Doppler flo w abnormality. Duplex-detected defects were graded with peak systolic velocity and velocity ratio criteria. Sites that demonstrated highly d isturbed flow (peak systolic velocity >180 cm/sec, velocity ratio >2.4 ) were immediately revised by direct repair, patch angioplasty, or int erposition grafting. Results: Intraoperative duplex scanning prompted revision of 50 abnormalities in 43 of the 275 grafts (16%), including 32 vein and seven anastomotic stenoses, nine vein segments with platel et thrombus, and two bypasses with low flow. The intraoperative revisi on rate was lowest (p < 0.02) for reversed saphenous vein bypasses (7% ) compared with other grafting techniques (in situ, 20%; nonreversed t ranslocated, 15%; spliced alternative vein, 23%). The revision rates o f popliteal and tibial bypasses were similar (14% vs 17%). A normal re sult shown by intraoperative scan (235 bypasses) was associated with a low 90-day thrombosis (0.4%) and revision (2%) rate, whereas six of 1 5 grafts (40%) with residual and 13 of 25 grafts (52%) with unrepaired duplex abnormalities required corrective procedures (p < 0.001). One graft failed within 3 months (secondary patency rate, 99%). Conclusion s: Intraoperative duplex scanning accurately predicted the technical a dequacy of infrainguinal vein grafts and was particularly useful in as sessing bypasses constructed with valve lysis techniques or alternativ e veins. Early graft revisions indicated by duplex monitoring for thro mbosis or stenosis were the result of a progression of residual defect s and platelet thrombus formation rather than inadequate graft run-off flow.