The clinical presentation and collateral pathway development of congenital absence of the internal carotid artery

From analysis of our 10 cases of ICA agenesis and our review of the relevant literature, we conclude that young patients with ICA agenesis may present with developmental delay, subarachnoid hemorrhage, or other developmental abnormalities, whereas older patients most commonly present with transient neurologic events. Complications of carotid agenesis are related to specific anatomic subtypes and the resulting collateral circulation development.