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Expected Duplex Ultrasound Results in Distal Revascularization and Interval Ligation Conduits
Alexis Graham1, M Libby Weaver2, Courtenay Holscher3
1Department of Surgery, The Johns Hopkins Hospital, Baltimore, MD.
Insights
Distal revascularization and interval ligation (DRIL) shows improved hemodynamics post-procedure. Elevated proximal anastomosis velocities on duplex ultrasound are common and do not indicate stenosis without other signs of compromise.
Area of Science:
- Vascular Surgery
- Noninvasive Vascular Testing
- Hemodynamics
Background:
- No established standards exist for noninvasive testing after distal revascularization and interval ligation (DRIL).
- This study aimed to define expected hemodynamic results and duplex ultrasound findings following DRIL.
Purpose of the Study:
- To evaluate the hemodynamic outcomes of DRIL using noninvasive testing.
- To characterize duplex ultrasound findings in DRIL conduits.
Main Methods:
- Retrospective review of patients undergoing DRIL with autogenous vein (2008-2019).
- Inclusion criteria: preoperative and follow-up noninvasive testing.
- Analysis of wrist brachial index, finger pressures, and duplex ultrasound parameters.
Main Results:
- Significant improvement in wrist brachial index (0.56 to 0.90) and finger pressure (56 to 73) post-DRIL (P < 0.001).
- Duplex ultrasound revealed consistently elevated velocities proximally (inflow, proximal anastomosis) and slower velocities distally (mid-conduit, distal anastomosis, outflow).
- This velocity pattern remained stable between first and second follow-ups.
Conclusions:
- Elevated proximal anastomosis velocities in DRIL bypasses are common and may be related to fistula hemodynamics.
- These high velocities do not necessarily indicate stenosis or require intervention if the conduit is otherwise intact.
Background:
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.
Methods:
A retrospective chart review of patients who underwent DRIL using autogenous vein between 2008 and 2019 was performed. Patients with both preoperative and follow-up noninvasive testing were included.
Results:
Thirty-eight patients were included in the study. Median time to first follow-up was 30 days (range 1-226 days), where 12 had complete resolution of their symptoms and 26 had partial resolution. Of the 27 patients that had preoperative and postoperative 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). Seventeen patients had a second follow-up (sFU) at a median time from DRIL of 196 days (range 106-843 days). There was no significant difference in wrist brachial index or finger pressures between first follow-up and sFU. Duplex ultrasound of the DRIL conduits (n = 32) showed a very consistent pattern with elevated median velocities proximally (inflow 235 cm/sec, proximal anastomosis 217.7 cm/sec) and distinctly slower median velocities distally (midconduit 46.4 cm/sec, distal anastomosis 78.3 cm/sec, outflow 59.3 cm/sec). The same pattern of velocities was held constant at the sFU (n = 16).
Conclusions:
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.
