Current evidence suggests that carotid endarterectomy (CEA) performed within 2 weeks of symptoms produces better long-term results than if it is delayed. Urgent endarterectomy following unstable presentations such as crescendo transient ischemic attack (cTIA) or progressive stroke has been associated with variable results. The evidence for this treatment strategy required reviewing. A systematic review of articles related to urgent CEA between 1980 and 2008 was performed. For cTIA, there was an odds ratio of 5.6 (95% confidence interval 3.3-9.7, p < or = .0001) for combined stroke or death compared with surgery for "standard" indications. For unstable stroke, the odds ratio was 5.5 (95% confidence interval 3.1-9.3, p < or = .0001). Patients with unstable neurologic presentations are at higher risk of complications if operated on urgently. Clearer definitions would help more precise patient selection to avoid inadvertently operating on patients with an unacceptably high risk of poor outcome.