Abstract 2431: Angiographic Distinctions Of Radiation-induced Carotid Vasculopathy: A Case-controlled Study

Background: Radiation-induced vasculopathy (RIV) predisposes survivors of head-and-neck cancers to refractory ischemic strokes. We aimed to investigate the angiographic extent and morphological attributes of symptomatic RIV. Methods: The study was approved by the Institutional Review Board and each participant provided an informed consent. One hundred thirty patients with ischemic strokes attributed to high-grade carotid stenoses (>60%) were recruited for digital subtraction angiograms (DSA). Among the enrolled patients, 65 had prior curative intent radiotherapy for head-and-neck cancers. The remaining 65 control patients who had no radiotherapy were presumed to have atherosclerotic vasculopathy. DSA revealed both carotid and vertebro-basilar circulations from the level of aortic arch up to intracranial branches. A radiologist blind to the group assignment recorded the distribution and characteristics of both stenotic and non-stenotic lesions. Fetal variant or incompetence of the circle of Willis, if any, was also documented. Results: The baseline characteristics of RIV and control patients were comparable except a lower prevalence of hypertension and diabetes mellitus in RIV group (p were atherosclerotic. Atherosclerotic stenoses were predominantly focal, involving the internal carotid artery adjacent to the bifurcation (93/103, 90.29%). RIV stenoses, in contrast, harbored more frequently at common carotid artery (96/176, 54.55%) and was associated with more tandem lesions (29.23% vs 10.77%, p Conclusion: Radiation-induced carotid disease was frequently bilateral and associated with concurrent tandem and vertebra-basilar steno-occlusions. Fetal variant or incompetence of the Circle of Willis may potentiate further the hemodynamic insufficiency.