Postoperative duplex scan surveillance of axillofemoral bypass grafts

Objective: Duplex scan surveillance (DS) for axillofemoral bypass grafts (AxFBGs) has not been extensively studied. The intent of this study was twofold: 1, to characterize the flow velocities within AxFBGs; and 2, to determine whether postoperative DS is useful in assessment of future patency of AxFBGs. Methods. We identified all patients who underwent AxFBG procedures between January 1996 and January 2001 at our combined university and Veterans Affairs hospital vascular surgical service. All grafts were performed with ringed 8-mm polytetrafluoroethylene with the distal limb of the axillofemoral component anastomosed to the hood of the femoral-femoral graft. DS was every 3 months for 1 year and every 6 months thereafter. Duplex scan results were compared in primarily patent grafts with grafts that thrombosed. Graft failures from infection were excluded. Influences of ankle-brachial index, blood pressure, outflow patency, operative indication, and comorbidities on graft patency were analyzed. Results. One hundred twenty patients underwent AxFBG procedures. Twenty-eight were excluded because of infection or death before surveillance examination. Fourteen were lost to follow-up, 23 had failed grafts from occlusion, and 55 had grafts that remained patent. In the 78 patients evaluated during long-term follow-up period, the mean peak systolic velocities (PSVs) at the proximal (axillary) anastomosis during the first postoperative year ranged from 153 to 194 cm/s. Mean PSVs at the mid portion of the axillofemoral graft during the first postoperative year ranged from 100 to 125 cm/s, whereas those for the distal axillofemoral anastomosis ranged from 93 to 129 cm/s. Mean midgraft and distal anastomotic velocities obtained before thrombosis were significantly lower in the thrombosed grafts compared with the last recorded velocities at the same sites in the patent grafts (mean PSV, 84 versus 112 cm/s; P = .015; mean PSV, 89 versus 127 cm/s; P = .024, respectively). Forty-eight percent of occluded grafts had a mean midgraft PSV at last observation of less than 80 cm/s. Blood pressure correlated with midgraft velocity (r = 0.415; P < .05). With multivariate logistic regression analysis, a mean midgraft velocity less than 80 cm/s was the sole independent factor associated with graft failure (P < .01). No patients with midgraft velocities greater than 155 cm/s had occlusion. Conclusion: Flow velocity varies widely within and among AxFBGs. Patency of AxFBGs is associated with higher midgraft PSV, and thrombosis with midgraft velocities less than 80 cm/s.