Background: The objective of this study was to assess whether carotid endarterectomy is an appropriate treatment for patients with recent cerebrovascular events in the territory supplied by a moderately stenosed (30-69%) internal carotid artery. Results have previously been reported for severe (70-99%) and mild (0-29%) stenosis.
Methods: A multicentre randomised controlled trial recruited 1599 patients with moderate stenosis treated in 97 hospitals from 15 countries. 60% of patients were allocated to receive and 40% to avoid carotid endarterectomy. The analysis was by intention to treat.
Findings: Nine patients were omitted from the analysis because no follow-up data were received. Stroke-free life expectancy (curtailed at 8 years) was shorter in the surgery patients than in the non-surgery control groups (patients with 30-49% stenosis, life expectancy = 6.16 years [controls: 6.63 years]; patients with 50-69% stenosis, life expectancy = 5.93 [6.14] years). It remains possible that patients might derive some benefit from surgery in the very long term; however, our data show that no benefit would be gained over a period of < 4-5 years in patients with 50-69% stenosis and < 6-7 years in patients with 30-49% stenosis.
Interpretation: Previous interim results from this study showed that surgery is beneficial in patients with severe stenosis but harmful in those with mild stenosis. With more randomised patients and longer follow-up, the study now shows that endarterectomy is not indicated for most, possibly all, patients with moderate symptomatic carotid stenosis.