PURPOSE: Early traditional methods of surveillance to detect failing graft relied on recurrence of symptoms, change of pedal pulses, or a decrease in the Ankle-Brachial Index (ABI). More recently, graft surveillance with Duplex scan which has become an appropriate first-line alternative has been shown to be effective in identifying the patency of threatened femorodistal graft. The purpose of this study was to determine the relationship and significance among ABI change, run-off resistance score, and Duplex scan parameters in femorodistal graft bypass. METHOD: Among 52 patients who received femorodistal bypass, thirty-one femorodistal grafts (19: above knee, 12: below knee) which had followed up for more than 2 years were followed up by ABI at regular interval and Duplex scan at 2 year. Those were grouped according to the grade of ABI decrease as follows; Group I: <0.1 ABI decrease, Group II: 0.1or= 0.2 ABI decrease. Peak systolic flow velocity (PSFV) ratio, luminal diameter at near proximal and distal anastomosis, mean body graft velocity (cm/sec) were evaluated. Runoff resistance score was calculated by the finding of the pre-operative angiogram. RESULT: In proportion to the severity of ABI decrease, proximal and distal peak systolic flow velocity (PSFV) ratio and stenosis (%) increased, mean body graft velocity decreased. Significant statistical difference between groups were shown as follows; Group II and IV: distal PSFV ratio (2.17 vs 2.95, P=0.02), proximal stenosis (32.8% vs 47.4%, P=0.026), distal stenosis (21.7% vs 62.0%, P=0.007), mean body graft velocity (81 cm/sec vs 46 cm/sec, P=0.02) Group III and IV: distal PSFV ratio (2.29 vs 2.95, P=0.02), distal stenosis (40.5% vs 62.0%; P=0.003), body flow velocity (70 cm/sec vs 46 cm/sec, P=0.02). The higher runoff resistance score was, the more distal PSFV ratio, distal stenosis increased, but proximal stenosis, PSFV ratio, and mean body graft velocity did not change significantly. CONCLUSION: This study shows that higher decrease in ABI (>0.2) is well correlated with critical Duplex parameters. Longer graft patency and economic benefit may be obtained by active evaluation of failing graft using by Duplex scan when the ABI decrease is more than 0.2 in femorodistal graft bypass at regular examination.
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