One-point measurement of the peak-to-peak pulsatility index as an indicator for evaluation of infrainguinal bypass procedures

Abstract

While duplex scanning has been advocated as the most accurate modality for postoperative graft surveillance, it is time-consuming for evaluating the entire graft. The aim of the present study was to determine which parameter predicts graft failure most simply and precisely, by examining 62 men and 1 woman who collectively underwent 71 infrainguinal arterial bypasses. A total of 212 scannings were obtained using a duplex scanner, and the peak systolic velocity (PSV), PSV ratio, and peak-to-peak pulsatility index (PPI) were analyzed. This analysis revealed 7 occlusions, 9 stenoses, and 1 arteriovenous fistula. When a PSV < 45 cm/s and/or a PSV ratio > 2.0 was defined as graft failure the sensitivity was 84.0% and the specificity was 81.8%: however, a PPI < 7.0 at the midgraft, indicating graft failure, showed a sensitivity of 100% and a specificity of 83.3%. The PPI exhibited better sensitivity and specificity than the PSV, even though the PPI needs only to be measured at the midgraft whereas the PSV should be measured at at least two points. Thus, we believe that the PPI could be the most useful and simple parameter to assess infrainguinal bypass grafts.

Usefulness of Peak-to-Peak Pulsatility Index in Infrainguinal Bypass Graft Surveillance

“…In this series, PPI criteria revealed excellent sensitivity and sufficient specificity as a screening test if the cutoff level was 7.0, which we also advocated in our previous study. 8 Several clinical series have shown that the PPI value exhibited sufficient sensitivity to predict significant proximal stenosis if no additional distal lesions, and hence no additional positive reflection sites, existed. 9-11 Johnston et al 10 assessed four methods, namely, pulsatility index, height-width index, path length index, and Laplace transform function index.…”