When the Conception of Symmetry Deceives Us: A Case Report on the Perioperative Diagnosis of Subclavian Artery Stenosis.

Subclavian artery stenosis is a relatively uncommon manifestation of peripheral artery disease with significant morbidity. We describe a case of left subclavian artery stenosis that became apparent in the intraoperative setting, in a patient who presented for emergency surgery after a fall and subsequent left femoral neck fracture. Initial non-invasive blood pressure readings on the left upper extremity were in the normal range but after placement of the arterial line on the right upper extremity, the discrepancy was evident pointing towards a structural abnormality as the causative factor. CT angiography was found to confirm the diagnosis of left subclavian artery stenosis of an atherosclerotic nature. A thorough physical examination can point to the presence of subclavian stenosis through pulse amplitude and blood pressure asymmetries. This study highlights the importance of obtaining blood pressure readings ideally on all four limbs to avoid misinterpretation of blood pressure values that could ultimately lead to the use of unnecessary and inadequate interventions and possible complications in the perioperative setting.