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

This is a case report published by Jien Saito et al.1 from Nagoya City University East Medical Center in Japan. The report is called “Management of Coronary Artery Bypass Grafting Using an Arteriovenous Fistula: An Intraoperative Change in the Preoperative Plan”. Transit Time Flow Measurement (TTFM) was used as quality control during the surgical procedure enabling immediate revision and change in surgical strategy.

Case report

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.

Case attachments

Click images below to view.
Schematic of surgical findings during a coronary angiography

Schematic of surgical findings

Schematic of surgical findings

MiraQ system display presenting analytical data results

LITA-HL graft before reanastomosis. TTFM showing a retrograde pattern.

LITA-HL graft before reanastomosis. TTFM showing a retrograde pattern.

transit time flow measurement (TTFM) screen

Free LITA-LAD graft after reanastomosis. TTFM showing improvement towards a progressive pattern.

Free LITA-LAD graft after reanastomosis. TTFM showing improvement towards a progressive pattern.

Schematic of surgical findings during a coronary angiography
Image 1

Image 1

MiraQ system display presenting analytical data results
Image 2

Image 2

transit time flow measurement (TTFM) screen
Image 3

Image 3

Reference

Link to open access case report:

Management of Coronary Artery Bypass Grafting Using an Arteriovenous Fistula: An Intraoperative Change in the Preoperative Plan

1 Saito J, Kamiya S, Numata Y, et al. (February 27, 2023) Management of Coronary Artery Bypass Grafting Using an Arteriovenous Fistula: An Intraoperative Change in the Preoperative Plan. Cureus 15(2): e35517. DOI 10.7759/cureus.35517

Schematic of surgical findings during a coronary angiography

Schematic of surgical findings

Schematic of surgical findings

MiraQ system display presenting analytical data results

LITA-HL graft before reanastomosis. TTFM showing a retrograde pattern.

LITA-HL graft before reanastomosis. TTFM showing a retrograde pattern.

transit time flow measurement (TTFM) screen

Free LITA-LAD graft after reanastomosis. TTFM showing improvement towards a progressive pattern.

Free LITA-LAD graft after reanastomosis. TTFM showing improvement towards a progressive pattern.