LAUSR

An 89-year-old female with a prior history of ischemic stroke, not on ACE inhibitor, presented to the emergency department for generalized malaise. During her initial evalu-ation she was noted to be hypotensive (64/44 mm) on two occasions with no other symptoms and was fluid resuscitated due to concern for hemodynamic instability. Her hemoglo-bin concentration was 6.1 g/dl. She was transferred to the intensive care unit with a blood pressure of 144/65 mmHg and one unit of red blood cells (RBCs) was ordered. Twenty minutes into the transfusion (50 ml transfused), the blood pressure was noted to be 72/49 mmHg without any other symptoms. The RBC unit was returned as part of a request to investigate a transfusion reaction. Shortly after, the blood pressure was reevaluated on the opposite arm showing over 100 mmHg difference between arms (systolic 75 mmHg-left arm; 180 mmHg-right arm). A CT chest angiogram revealed subclavian steal syndrome. The image shows an oblique coronal view using curved planar reformation (Figure 1). A non-calcified and calcified plaque at the origin is completely occluding the proximal left subclavian artery (white arrow) with distal reconstitution from the ipsilateral vertebral artery (white arrowhead). This finding accounts for the difference in blood pressure measurements, related to