An ultrasonic study of the relationship between extracranial carotid atherosclerosis and ischemic cerebrovascular disease in Japanese

Abstract

The study is to evaluate the relationship between extracranial carotid atherosclerosis and ischemic cerebrovascular disease using noninvasive B-mode ultrasonography and X-ray computed tomography. The sensitivity of bruits for diagnosing severe carotid stenosis was also evaluated. A total of 229 consecutive Japanese patients were recruited for this study, of which 97 had chronic-stage ischemic cerebrovascular disease and remaining 132 patients had at least one risk factor for atherosclerosis. Carotid atherosclerosis was evaluated by B-mode ultrasonography. Ischemic cerebrovascular disease was assessed by history taking, neurological findings and X-ray CT examination. The severity of carotid atherosclerosis was assessed by using two indices; plaque score and maximum percentage diameter stenosis. We also evaluated whether it was ulcerated plaque or not. Plaque score was computed by summing up all carotid plaque thicknesses (mm) on both sides. According to the CT findings, cerebral infarction was divided into two types; deep subcortical infarction and cortical infarction. The incidence of cerebral infarction increased in relation to plaque score and maximum percentage stenosis. Although the incidence of cerebral infarction in patients without carotid atherosclerosis was only 33% (38/116), it in patients with moderate carotid atherosclerosis (plaque score > 5) was 59% (26/44) (p < 0.05, chi-square test). The incidence of ipsilateral infarction was revealed to be higher in patients with severe (50% or more) carotid stenosis (61%) than in cases of mild stenosis (28%) (p < 0.05). Thirteen patients had ulcerated plaques and they suffered more frequently cerebral infarction than patients without ulcerated lesions. Cortical infarction was more frequent in patients with severe carotid stenosis than in patients without carotid atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)