Usefulness of duplex scanning for following prosthetic grafts in above-knee femoropopliteal bypass: A new indicator for identification of failing grafts

Abstract

To assess the utility of routine duplex surveillance for prosthetic grafts in above-knee femoropopliteal bypass, 33 prosthetic grafts (expanded polytetrafluoroethylene; ePTFE 26, externally supported Dacron graft; EXS 7) were prospectively entered into a surveillance protocol from April 1990 through August 1994. Peak systolic flow velocity (PSFV), measured in two segments (midportion of the graft and host popliteal artery), was performed every 3 months. The mean value at the last point is compared between the patent group (n=28) and the occluded group (n=5). The means ± standard deviation (SD) of PSFV at the midportion of the graft are not significantly different in either group (patent group 36.4±7.0 cm/second, occlusive group 34.9±10.0 cm/second). For PSFV at the host popliteal artery, there is a tendency for the means ± SD of PSFV in the patent group to be superior to those in the occluded group (patent group 39.9±12.0 cm/second, occluded group, 29.6±7.4 cm/second). The mean rate of PSFV at the midgraft to PSFV at the popliteal artery (midgraft-popliteral artery index; MPI) in the occluded group is significantly lower than that of the patent group (patent group 1.2±0.3, occlusive group; 0.8±0.2,p<0.01), whereas all anklebrachial index (ABI) of the occluded group at the last point is higher than 0.85. Measurements of PSFV in two segments and calculation of MPI by using duplex scanning are more reliable in identifying failing prosthetic grafts than is determination of ABI.