Peripheral bypass reoperation: Detection of thrombus and side branches in graft

Patient information:

Patient medical history: Patient with PAD and Fontaine stage IV on the right side (Image 1).

Initial surgery: Fem-pop bypass using the great saphenous vein (SVG) in situ as graft. The surgery went uneventfully and TTFM showed 41 mL/min with a PI of 2.9 after ligation of all residual saphenous vein side branches that were visible on angio (Image 2).

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Reoperation: Detection of thrombus and side branches in graft

On post-OP day 8, the patient experienced pain in the foot. Percutaneous ultrasound showed a distal occlusion of the SVG as well as flow in the vein side branch. The patient was readmitted for surgery and during the procedure, HFUS revealed a large open side branch and a thrombus in the vein graft (Image 3 and 4). The following TTFM readings were all performed on different parts of the SVG.

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• ‍TTFM at site M1 confirming significant flow in side branch (Image 5):

TTFM was first performed at site M1 proximally to the open side branch and the occluded area. TTFM at M1 showed 429 mL/min with a PI of 0.5 suggesting that a lot of the blood was flowing through the side branch. A large thrombus was identified in the SVG graft, possibly caused by the high flow in the side branch and low flow in the graft.

• ‍TTFM at site M2 after thrombectomy and ligation of the side branch (Image 6):

A thrombectomy was performed and the side branch closed. TTFM at site M2, measured distally to the closed side branch, showed 122 mL/min with a PI of 2.4.

• ‍TTFM at site M3 suggesting another side branch (Image 7):

TTFM was performed at site M3 close to the distal anastomosis, and yet again it showed reduced flow of 38 mL/min with a PI of 5.6. This suggested a second side branch located between M2 and M3.

• ‍TTFM at site M4 showing acceptable flow (Image 8):

After ligating the second side branch, TTFM at site M4 showed 40 mL/min with a PI of 7.5. The high PI may be due to high resistance in the tibial trunk, hence, angioplasty of the tibial trunk was performed simultaneously. A final TTFM was performed with an acceptable flow and PI.

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This case shows how TTFM and HFUS can provide helpful surgical guidance by identifying significant side branches and thrombus in lower limb in-situ bypasses.