Cerebrovascular steal phenomenon in a patient undergoing dipyridamole nuclear perfusion cardiac imaging.

Transient ischemic neurological deficits following intravenous dipyridamole administration during pharmacological cardiac stress test are seldom reported, but there can be serious vascular complications. We report a case of a 58-year-old Caucasian male who developed expressive aphasia after dipyridamole infusion during an elective dipyridamole-technetium cardiac stress test performed for chest pain. Computed tomography angiogram of the neck revealed a known total occlusion of the right internal carotid artery and 50% stenosis of the left internal carotid artery. The patient's aphasia spontaneously resolved within 24 h. In this paper, we report a unique case in which the administration of intravenous dipyridamole precipitated transient ischemic attack in a patient with stable asymptomatic bilateral carotid artery disease and prior carotid endarterectomy. We also discuss the intracerebral vascular steal phenomenon as a possible pathophysiological mechanism in this patient.