Expected Duplex Ultrasound Results in Distal Revascularization and Interval Ligation Conduits

Abstract

There are no published standards for the expected findings on noninvasive testing following distal revascularization and interval ligation (DRIL). This study evaluated the hemodynamic results and duplex ultrasound characteristics of DRIL. A retrospective chart review of patients who underwent DRIL using autogenous vein between 2008-2019 was performed. Patients with both preoperative and follow-up noninvasive testing were included. 38 patients were included in the study. Median time to first follow-up (fFU) was 30 days (range 1-226d) where 12 had complete resolution of their symptoms and 26 had partial resolution. Of the 27 patients that had pre- and post-operative testing, the wrist brachial index improved from 0.56 to 0.90 with the median finger pressure improving from 56 to 73 (p<0.001). 17 patients had a second follow-up (sFU) at a median time from DRIL of 196d (range 106-843d). There was no significant difference in WBI or FP between fFU and sFU. Duplex ultrasound of the DRIL conduits (n=32) showed a very consistent pattern with elevated median velocities proximally (inflow 235cm/s, proximal anastomosis 217.7cm/s) and distinctly slower median velocities distally (mid-conduit 46.4cm/s, distal anastomosis 78.3cm/s, outflow 59.3cm/s). The same pattern of velocities held constant at the sFU (n=16). In this study, velocities at the proximal anastomosis were significantly higher than velocities more distal in the DRIL bypass without evidence of stenosis. This may be due to hemodynamic changes in the brachial artery associated with presence of a fistula. Elevated velocities at the proximal anastomosis do not necessarily warrant further evaluation or intervention without other evidence of conduit compromise.