Silent cerebral infarction: Risk factor for stroke complicating carotid endarterectomy

"Silent" cerebral infarction is found in 20% to 30% of patients with signif icant internal carotid artery (ICA) disease. Our purpose was to determine w hether such "silent" cerebral infarction in the operated carotid territory represents a risk factor for stroke during and immediately after carotid en darterectomy. Over 5 years we followed a cohort of 663 patients with sympto matic and asymptomatic ICA stenosis who were consecutively scheduled for su rgery. The stenosis was more than 70% in patients with transient ischemic a ttacks and more than 95% in asymptomatic stenosis patients. All patients un derwent preoperative computed tomography to determine the frequency, extent , and location of any "silent" cerebral infarction. Patients were grouped b y the absence or presence of infarction in the operated carotid territory. Among the entire cohort, 20 patients had a major perioperative stroke (3.0% ). All deaths were stroke-related. No intracranial bleeding occurred. Major stroke occurred in four (0.8%) patients without appropriate "silent" cereb ral infarction, compared with 16 (8.8%) with an appropriate "silent" cerebr al infarct (p < 0.001). After adjustment for confounding co-variables (e.g. , gender, presence of preoperative symptoms, and age), "silent" cerebral in farction was found to be the only independent predictor of perioperative ma jor stroke for symptomatic and asymptomatic stenosis (overall adjusted rela tive risk 11.5, 95% confidence interval 3.8-34.9, p < 0.0001). Patients wit h "silent" cerebral infarction seem to be at increased risk of perioperativ e stroke. Consequently, preoperative cerebral imaging is important for risk classification.