Case report
A 48-year old female was referred for surgical revascularisation. She had been admitted with worsening angina and increasing exertional dyspnoea. She had suffered a non-ST elevation myocardial infarction 1-year prior to referral and had her left main stem stented. Her past medical history included: obesity and a right hip replacement. She was an ex-smoker with a 15-pack-year history and had a strong family history of ischaemic heart disease.
Her angiogram confirmed significant in-stent restenosis of the left main stem, with 50% stenosis and an instant flow reserve (iFR) 0.82, and a severe ostial left circumflex lesion. Echocardiogram confirmed good left ventricular function and no significant valvular pathology.
The patient underwent CABG x 2. Prior to establishing bypass, the pedicled LIMA flow was assessed as reasonable, at high pressures, and was subsequently anastomosed to the left anterior descending (LAD) artery. There was myocardial contraction observed upon release of LIMA flow suggesting no technical issue with the anastomosis. The heart was subsequently weaned from cardiopulmonary bypass with no inotropic support. Shortly after, pronounced anterolateral ST-depression was observed followed by haemodynamic instability prompting going back onto bypass.
The LIMA-LAD anastomosis was taken down in view of the pattern of ischaemia. Good flow was observed from the LIMA and there was no evidence of a technical problem, however the decision was made to perform a vein graft to the LAD. The LIMA was not used as a free graft as there was concern that there may have been an injury to the vessel as the cause of the problem. The remainder of the procedure proceeded uneventfully, and she was transferred to the ITU with no inotropic support. To further investigate, a CT-aortogram was performed which confirmed complete occlusion of the proximal left subclavian artery at its origin (Figure 1), suggesting the intraoperative picture was that of coronary-subclavian steal syndrome. She was treated with antibiotics for a chest infection, but otherwise made an uneventful recovery and was discharged on the 7th postoperative day.