Simplified Screening of Lower Extremity Arterial Bypasses

This study assessed a new technique comparing the width of the distal Doppler signal with that of the proximal Doppler signal in order to detect intervening bypass graft or anastomotic stenoses. The width of the Doppler signal was defined as the time from the initial Doppler signal upstroke until the time the signal returned to within 10% of its baseline. The width of the distal Doppler signal was compared with the width of the proximal Doppler signal for 11 normal bypasses and for 11 bypasses with a significant intervening stenosis. The distal Doppler signal was at least 10% wider than the proximal Doppler signal in all bypasses with a significant intervening stenosis, unlike most bypasses without an intervening stenosis (P<0.001). This technique detected all the significant bypass graft stenoses while eliminating the need to do complete bypass graft duplex ultrasound studies on most normal bypasses.