Are Cerebral White Matter Lesions Related to the Presence of Bilateral Internal Carotid Artery Stenosis or to the Length of Stenosis Among Patients With Ischemic Cerebrovascular Events?

Background and purpose: Previous studies delivered contradicting results regarding the relation between the presence of an internal carotid artery stenosis (ICAS) and the occurence of white matter lesions (WMLs). We hypothesize that special characteristics related to the ICAS might be related to the WMLs. We examined the relation between the presence of bilateral ICAS, the degree and length of stenosis and ipsi-, contralateral as well as mean white matter lesion load (MWMLL). Methods: In a retrospective cohort, patients with ischemic stroke or transient ischemic attack (TIA) as well as ipsi- and/or contralateral ICAS were identified. The length and degree of ICAS, as well as plaque morphology (hypoechoic, mixed or echogenic), were assessed on ultrasound scans and, if available, the length was also measured on magnetic resonance angiography (MRA) scans, and/or digital subtraction angiography (DSA). The WMLs were assessed in 4 areas separately, (periventricular and deep WMLs on each hemispherer), using the Fazekas scale. The MWMLL was calculated as the mean of these four values. Results: 136 patients with 177 ICAS were identified. A significant correlation between age and MWMLL was observed (Spearman correlation coefficient, rho = 0.41, p < 0.001). Before adjusting for other risk factors, a significantly positive relation was found between the presence of bilateral ICAS and MWMLL (p = 0.039). The length but not the degree of ICAS showed a very slight trend toward association with ipsilateral WMLs and with MWMLL. In an age-adjusted multivariate logistic regression with MWMLL >= 2 as the outcome measure, atrial fibrillation (OR 3.54, 95% CI 1.12-11.18, p = 0.03), female sex (OR 3.11, 95% CI 1.19-8.11, p = 0.02) and diabetes mellitus (OR 2.76, 95% CI 1.16-6.53, p = 0.02) were significantly related to WMLs, whereas the presence of bilateral stenosis showed a trend toward significance (OR 2.25, 95% CI 0.93-5.45, p = 0.074). No relation was found between plaque morphology and MWMLL, periventricular, or deep WMLs. Conclusion: We have shown a slight correlation between the length of stenosis and the presence of WMLs which might be due to microembolisation originating from the carotid plaque. However, the presence of bilateral ICAS seems also to be related to WMLs which may point to common underlying vascular risk factors contributing to the occurrence of WML.