A rare case of Subclavian steal, caused by an arteriovenous fistula

The patient was a 78-year-old man with end-stage renal disease who experienced angina pectoris during hemodialysis. A coronary angiography showed a two-vessel lesion, including the left main coronary trunk. Ultrasound measurement of flow in the AVF showed high flow: 1.132 mL/min.

The preoperative plan was to perform an Off-pump CABG with LITA to LAD, RITA to the high lateral branch (HL), and an SVG to the posterolateral branch.

Based on the finding that the free flow in the in-situ LITA was 20 mL/minute with a weak pulsation, the team was concerned it would be insufficiency for revascularization of the LAD with high flow demand, and they revised the preoperative plan to anastomose RITA to LAD instead. They also evaluated LITA after anastomosis to HL. After completion of all anastomoses, as feared, the LITA graft demonstrated retrograde blood flow, which suggested the occurrence of ITA anomalies or subclavian steal. See Image 1 showing a schematic overview of surgical findings.

TTFM of LITA-High lateral branch before re-anastomosis shows a retrograde flow pattern in systole. The low flow of the LITA and high flow in the AVF indicated that the original blood flow of the LITA might have been drawn into the AVF, see Image 2.

The LITA graft was transected at the proximal part and anastomosed to the saphenous vein graft with sufficient flow to reach the HL (14 mL/min, see Image 3) as a Y-composite graft. Postoperative angiography showed good patency of all bypass grafts. The patient was discharged from the hospital 16 days after surgery.

In this case TTFM helped the surgeons make the decision to use LITA as a free graft after a measurement on the in-situ LITA. Resulting in an increase of flow from negative to 14 mL/min and reducing PI from 12.2 to 2.2.

For CABG in a patient on hemodialysis with an AVF, the blood flow of the AVF and free flow of the ipsilateral ITA are regarded as predictive factors of coronary subclavian steal syndrome occurrence. However, they do not represent decision factors. The ipsilateral ITA may be used as a free graft and not as an in-situ graft in cases where there are concerns about ipsilateral ITA blood flow to prevent subclavian steal.