Real-world replication of randomized controlled trial results for carotid endarterectomy

The efficacy of carotid endarterectomy (CE) has been shown in randomized clinical trials (RCTs), but doubts remain about whether the results can be replicated in routine clinical practice, especially in asymptomatic patients for whom the absolute risk reduction shown in the trials is small. In particular, a low rate of short-term adverse events is required for the long-term benefits of CE to accrue over time.

To determine whether the incidence of short-term adverse events after CE met the standards established by the major RCTs and those recommended by major clinical practice guidelines. Design, Setting, and Patients We used clinically detailed data derived from a comprehensive medical record review to measure the short-term adverse outcomes of CE, focusing on in-hospital death and stroke, in 3283 cases in western Canada in 2000 and 2001, and compared the results with those from the RCTs.

For symptomatic patients, the in-hospital ischemic stroke or death rate was 3.9%; for asymptomatic patients, the rate was 2.6%. Extrapolating our in-hospital results to the 30-day post-CE results of the RCTs gave stroke or death rates of 4.9% for cases involving symptomatic patients and 4.1% for cases involving asymptomatic patients. These results are comparable to or better than those of the major RCTs for symptomatic patients but slightly worse for asymptomatic patients. About 45% of hospitals had adverse event rates higher than those recommended by authoritative clinical practice guidelines.

This large population-based study shows that the RCT results for CE can be achieved in the real world. However, the finding that some hospitals exceeded the maximum suggested rates of adverse events highlights the need for continuous outcome monitoring and associated quality improvement efforts to ensure that all providers and institutions involved achieve desired outcomes.