Carotid Recurrent Stenosis and Risk of Ipsilateral Stroke

BACKGROUND: The main goal of follow-up after carotid endarterectomy is to prevent new strokes caused by recurrent stenosis. To determine the most cost-effective follow-up schedule, it is necessary to know the incidence of recurrent stenosis and the risk of stroke it carries. METHODS: A systematic review of the literature was performed using standard meta-analytical techniques. RESULTS: Incidence of recurrent stenosis: The data were very heterogeneous. The risk of recurrent stenosis was 10% in the first year, 3% in the second, and 2% in the third. Long-term risk of recurrent stenosis is about 1% per year. Risk of stroke: The reported relative risks of stroke in patients with recurrent stenosis compared with patients without recurrent stenosis showed extreme heterogeneity and ranged from 10 to 0.10. The random effects summary estimator of relative risk was 1.88. CONCLUSIONS: The data were very heterogeneous, and much better data are needed to arrive at truly reliable estimates of these important parameters of follow-up. It is clear, though, that the risk of recurrent stenosis is highest in the first few years after carotid endarterectomy and very low in later years. By use of general decision-analytic arguments, it can be argued that, given the test characteristics of carotid ultrasound, a small number of tests can be done in the first few years and that testing for restenosis should not be done after 4 years.