A Case Study Demonstrating the Utility of Duplex Ultrasonography as the Sole Imaging Modality in the Surveillance and Repair of Lower Extremity Arterial Bypass Grafts

Abstract

Introduction

Traditionally, duplex ultrasonography has played a secondary role in the pre-operative assessment of lower extremity arterial bypass graft revision, being used more as a follow-up tool, with more expensive and invasive modalities being used primarily. This case demonstrates the accuracy and reliability of using duplex ultrasonography alone in the management of lower extremity bypass graft revision, as well as postoperative follow-up.

Case Report

A 76-year-old man was seen in the diagnostic vascular unit for 2-week postoperative assessment after a left common femoral artery (CFA) aneurysm repair. Five months previously he had undergone right lower extremity femoral-to-posteriortibia in situ bypass graft for superficial femoral artery occlusion and a popliteal artery aneurysm. Ankle brachial indices were performed at his 2-week follow-up and showed a significant decrease in the right ankle brachial index (ABI) from 0.79 to 0.41. A right lower extremity duplex ultrasonography was performed and revealed significantly decreased flow velocities within the graft secondary to an arteriovenous fistula (AVF) found at the midthigh. The patient was scheduled for ligation of the AVF to restore adequate flow to the right lower extremity. The right thigh AV fistula was marked with duplex ultrasonography immediately before surgery. An incision was made directly over the marked AVF site, and the vein graft was isolated, revealing a large posterior medial AV fistula. Postoperative ABIs were significantly increased to 0.85 on the right side.

Conclusions

This case demonstrates the usefulness, accuracy, and reliability of duplex ultrasonography in the management of lower extremity arterial bypass grafts. All preoperative decisions were made on the basis of noninvasive vascular laboratory studies.