Cerebral tomographic findings in patients undergoing carotid endarterectomy for asymptomatic carotid stenosis: short-term and long-term implications

Purpose: Preoperative cerebral imaging has been considered not to be cost-e ffective in carotid endarterectomy (CEA) for asymptomatic carotid stenosis. Yet, silent brain infarction (SBI) has been associated with the embolizati on potential of a severe carotid stenosis. Thus the presence of SBI may rep resent an additional indication for CEA in asymptomatic patients. We examin ed the predictive value of preoperatively detected silent cerebral lesions on early and late outcomes in patients undergoing CEA for asymptomatic caro tid stenosis. Methods: Preoperative cerebral tomographic (CT) scans performed on 301 asym ptomatic patients undergoing 346 CEAs from 1986 to 1995 were reviewed by a single neuroradiologist blinded to patients' records. Mean follow-up was 67 .3 months (range, 24-130 months). The degree of internal carotid lumen redu ction was measured bilaterally in all patients (602 carotid arteries); caro tid stenosis of 60% or more was found in 399 carotid arteries. Results: Of the 103 (34%) CT scans positive for cerebral lesions, 58% were lacunar. No significant association was observed between the side of the ce rebral lesion on CT scan and the severity of the corresponding carotid sten osis; 38 silent lesions were detected in the 203 hemispheres ipsilateral to carotid stenoses that were less than 60% versus 95 SBIs in the 399 hemisph eres ipsilateral to carotid stenoses that were 60% or more (19% vs 24%; P = .2). There were no significant differences in the perioperative stroke/dea th rate in patients with or without cerebral CT lesions (2% vs 1%; odds rat io, 1.94; P = .6). Mortality rate during follow-up was 22% in patients with preoperative SBI and 15% in patients without SBI (P = .1). However, actuar ial survival at 10 years was shorter (P = .02) in patients with SBI. Late s troke occurred in 11% of patients with preoperative SBI and in 3% of patien ts without preoperative SBI (P = .006). Cox regression analysis showed that both preoperative lacunar and nonlacunar infarctions were independent pred ictors of late stroke (hazard ratio, 3.6; P = .04; and hazard ratio, 7.1; P = .001; respectively). Conclusion: In our experience, preoperative SBI did not occur more frequent ly in the hemisphere ipsilateral to asymptomatic severe carotid stenosis. A lthough our study lacks a medically treated control group, our data show th at SBI is predictive of poor neurologic outcome in asymptomatic patients un dergoing CEA. We conclude that CT before CEA, selectively applied, provides information on long-term neurologic prognosis and that a less aggressive a ttitude towards CEA in asymptomatic patients with SBI may be justified.