Subclavian stenosis causing angina after coronary artery bypass grafting

The Medical Journal of Australia ISSN: 0025729X 16 March 2009 190 6 331-332 ©The Medical Journal of Australia 2009 www.mja.com.au Lessons from Practice after coronary artery bypass using internal mammary Unfortunately, this simple non-invasive assessm overlooked, as it was in the patients reported here. approach to catheterisation of the left internal ma (LIMA) graft can also cause the diagnosis to be m catheter can often cross a significant subclavian sten po or sy A tentially clinically significant stenosis in the subclavian brachiocephalic arteries will produce a difference in stolic blood pressure between the right and left brachial arteries of 15–20 mmHg or more. Therefore, bilateral arm blood pressure measurements should be taken in symptomatic patients artery grafts. ent is often A haphazard mmary artery issed, as the osis. Meticulous comparison of the subclavian and aortic pressure tracings will identify the gradient and enable diagnosis. The difference in pressure between the arms may be reduced or absent in patients with significant bilateral subclavian and/or brachiocephalic disease, a scenario more likely in patients with extensive atherosclerotic peripheral vascular disease elsewhere. Coronary subclavian steal syndrome describes angina related to a subclavian stenosis with retrograde flow up the LIMA graft. This reverse LIMA flow results from lower vascular resistance and blood pressure in the arm compared with the myocardial territory supplied by the LIMA. However, steal with reverse LIMA flow is not an Clinical records