Intra-operative graft blood flow related to failure of femoro-popliteal bypass grafts.

The prognostic significance of intra-operative blood flow, as measured by electromagnetic flowmetry, was investigated in 127 limbs, which were operated on with a reversed femoropopliteal saphenous vein bypass graft because of symptomatic atherosclerotic occlusion of the superficial femoral artery. Thromboses occurring in the first postoperative month are defined as early failures and thereafter as late failures. There were three early graft failures. The basal and augmented flow rates during pharmacological vasodilation of these grafts were less than half those of the grafts remaining patent. Eight additional late graft occlusions occurred. Whereas the basal blood flow of these grafts did not differ significantly from that of the grafts which remained patent, the maximal flow rate was significantly lower (p less than 0.05). The overall incidence of graft failure at basal and maximal flow rates of 100 ml/min or less and 150 ml/min or less, respectively, was 35%, while, at higher flow rates, this incidence was reduced to 5% (p less than 0.001). This study emphasizes that intra-operative femoropopliteal vein graft flow provides prognostic indications of graft failure.