Prediction of cerebral ischemia during carotid stenting depending on the intensity of the preoperative ultrasound signal from the plaque

Abstract

Carotid stenting is an effective method for improving cerebral perfusion; risk assessment of cerebral embolism associated with this intervention remains a hot research topic. Objective: to identify predictors of cerebral embolism associated with carotid angioplasty with stenting (CAS). Material and methods. A prospective exploratory research included 46 patients (age from 44 to 81 years, median 65 years) with atherosclerotic stenosis of the internal carotid artery, who underwent CAS and were treated at the Scientific Center of Neurology (Moscow). The study did not include patients with restenosis, stroke with severe disability, contraindications for antiplatelet therapy, statins, and MRI examination. All patients underwent preoperative ultrasonographic (US) examination and postoperative histological examination of particles in carotid stent embolic protection devices. The state of the brain was assessed before and 24 hours after CAS using diffusion-weighted MRI. To identify predictors of the development of cerebral embolism, the clinical characteristics of patients, together with ultrasonographic and morphological data, were examined in a multivariate statistical analysis.Results. Preoperative US signal from an atherosclerotic plaque of high (estimated above 35 dB) intensity was associated with dense matter (in a protective device) of the "fibrosis with calcification" and "calcification" type and with a high probability (80%; 95% confidence interval 71–85% ) predicted intraoperative embolization of cerebral vessels with the acute ischemic lesions (AIL) formation. In a low (not higher than 35 dB) intensity of the preoperative ultrasound signal, the probability of AIL formation was statistically significantly lower (50%). Conclusion. There is a direct correlation between the intensity of the ultrasound signal and the density of the substance in the protective device. A high intensity of the preoperative ultrasound signal (estimated above 35 dB) is an unfavorable predictor of AIL, associated with CAS (with a probability of about 80%).