Cerebral Autoregulation in Unilateral Carotid Agenesis: How Low Can We Go?

Dysgenesis of the internal carotid artery (ICA) is a rare vascular disorder. It has a variety of different grades (agenesis, aplasia, and hypoplasia) and is more common on the right side. Although the ICA is an important vessel, most patients are asymptomatic due to collateral circulation. Recognition of this rare anomaly is important, particularly when considering patients for surgeries that demand permissive hypotension. We present and discuss the perioperative implications of a rare case of congenital absence of left carotid artery proposed for an urgent laryngeal biopsy and tracheostomy. The internal jugular vein was invaded with a tumor and so was removed, affecting venous drainage.