Discrepancies between Intracranial and Extracranial Vascular Lesions in Atherothrombotic Brain Infarction

Discrepancies between the degrees of pathological change in intracranial main arteries and the carotid arteries are occasionally observed in patients with atherothrombotic brain infarction (AI). We studied the differences in severity between these vascular lesions and the risk factors in AI. A retrospective study was done on 46 hospitalized patients with AI between April, 2002 and October 2003. We evaluated the degrees of stenosis in intracranial lesions by MRA and in extracranial lesions by carotid ultrasonography. The severity of the vascular lesions was evaluated from the percentage diameter stenosis on MRA images for the intracranial lesions and plaque score on ultrasound images for the extracranial lesions. Age, sex, hypertension, diabetes mellitus, hyperlipidemia and smoking were selected as risk factors for AI. Stepwise multiple regression analysis revealed that age (p>0.01, β0.383) and smoking (p< 0.05, β 0.341) were independent risk factors for PS. We reviewed 43 patients with carotid artery lesions (PS ≥ 5.1) but without intracranial artery stenosis (≥ 50%) (Group1, n=13), with intracranial artery stenosis but without carotid artery lesions (Group2, n=13), and with both carotid artery lesions and intracranial artery stenosis (Group 3, n=17). The patients in Groups 1, 2 and 3 were aged 60.3±10.4 years, 71.0±10.2 years, and 72.1 ± 6.80 years, respectively (ANOVA, p < 0.05, p < 0.01). Patients in Group 1 were significantly younger than those in Group 2 and 3. Group 1 exhibited diabetes mellitus more frequently (p < 0.05) than Group 2 or 3. Group 1 exhibited hyperlipidemia more frequently (p < 0.05) than Group 2. In conclusion, there was some difference in the progression of atheromatous change between intracranial arteries and carotid arteries. Risk factors may contribute to this difference.