Are Noninvasive Doppler Arterial Studies Useful in Predicting Success of Infrainguinal Bypass Grafts?

The prediction of success of lower extremity bypass grafts based solely on noninvasive Doppler flow data has been questioned. The prognostic value of preoperative Doppler ankle pressures (APR), ankle/brachial indices (ABI), be low-knee pressures (BKPR), above-knee pressures (AKPR), and segmental pressure gradient indices was examined in predicting immediate (IF), late (LF), and overall failure (OF), as well as amputation (AMP) in 168 infrainguinal bypass grafts. Good runoff (2-3 vessels) was present in only 36%, and vein grafts were used in 60% of limbs. OF occurred in 26.7% (IF 6.5%, LF 20.2%) with a mean follow-up of 16.2 months (range 0-63). Major AMP resulted in 17.2% limbs. In 140 limbs with audible Doppler pedal signals, there was no significant difference in AKPR, ABI, or segmental indices between successful and failed grafts. Successful grafts had a higher AKPR (114.8 ± 38.5 vs 100 ± 30.5, p < .05) and BKPR (87.9 ± 30 vs 72.2 ± 23.5, p < .01) compared with failed bypasses. No significant differences in IF, LF, or OF rates were noted in limbs with ABI < 0.2 vs > .02, < .04 vs > .04 or presence/absence of Doppler pedal signals. Preoperative noninvasive Doppler flow studies are invaluable in the diagno sis, grading, and follow-up of unoperated patients with lower extremity arterial occlusive disease or detection of impending graft failure. They do not reliably predict success/failure of infrainguinal bypass grafts in individual patients. Low ABI or absent Doppler pedal signals do not by themselves preclude successful revascularization.