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.