Background and purpose: Atherosclerosis is the main cause of common carotid artery occlusion in most reports. This study aimed to identify the major causes of common carotid artery occlusion and compare the clinical features and carotid duplex ultrasonography findings of patients with common carotid artery occlusion attributable to each cause.
Methods: Patients with common carotid artery occlusion documented by carotid duplex ultrasonography at the Neurovascular Laboratory (National Taiwan University Hospital) from 1988 to 2003 were included. Medical records and ultrasonographic findings were reviewed in detail to clarify the possible etiology of common carotid artery occlusion.
Results: A total of 44 patients (male, 27 [61%]; female, 17 [39%]; mean age, 58 years) had common carotid artery occlusion attributable to a carotid duplex ultrasonography-identifiable cause. The causes of common carotid artery occlusion included atherosclerosis (17 [39%]), Takayasu's arteritis (11 [25%]), postirradiation arteriopathy (7 [16%]), cardiac embolism (6 [14%]), syphilis (1), blunt trauma (1), and homocystinuria (1). Among the patients with common carotid artery occlusion due to the 4 major causes, 27 (66%) had ischemic stroke and 14 (34%) had no symptoms or nonlocalizing symptoms. The frequency of symptomatic com mon carotid artery occlusion was 83% in those with cardioembolism, 76% in those with atherosclerosis, 71% in those with postirradiation arteriopathy, and 36% in those with Takayasu's arteritis. Common carotid artery occlusion usually involved the carotid bulb and distal common carotid artery in atherosclerosis (88%) and postirradiation arteriopathy (100%), but not in Takayasu's arteritis (27%). Echogenicity of occluded material was heterogeneous in atherosclerosis and post-irradiation arteriopathy patients but homogeneous in all Takayasu's arteritis patients. The authors postulate that the thrombotic mechanism might differ according to etiology.
Conclusions: The causes of common carotid artery occlusion are diverse. Atherosclerosis, Takayasu's arteritis, and post-irradiation arteriopathy are the most common causes of com mon carotid artery occlusion in Taiwan. The clinical features, pathophysiology, and carotid duplex ultrasonography findings vary according to the cause of common carotid artery occlusion.