Carotid artery stenosis in asymptomatic patients who have received unilateral head-and-neck irradiation

Abstract

To determine the prevalence of carotid artery stenosis in patients who have received ipsilateral head-and-neck radiotherapy and have no symptoms of cerebrovascular disease. Forty patients underwent ultrasound and computed tomography angiography of their carotid arteries. The vessels on the irradiated side were compared with those on the unirradiated side in a matched-pair analysis with regard to any stenosis, stenosis > or =60% in the internal carotid artery/carotid bulb, intima medial thickness (IMT), and grade of wall abnormalities. History, physical, and fasting blood levels were taken to detect risk factors for carotid disease. Fourteen irradiated carotid trees bore one or more stenosis vs. five in the unirradiated ones (p = 0.03). There were six bulb/internal carotid artery stenoses > or =60% in the irradiated carotids vs. one in the unirradiated (OR 6:1, p = 0.13). IMT and grade of vessel wall abnormality were higher in the irradiated carotids, but only at doses > or =50 Gy, and only at measurement points that lay within the radiation portals. Radiation appears to cause carotid artery stenosis. There may be a dose threshold for carotid wall changes, which has relevance for radiotherapy in several tumor sites.