Carotid endarterectomy represents one of the main strategies for primary and secondary prevention of atherothrombotic ischemic stroke. ECST and NASCET studies on symptomatic carotid stenosis showed a significantly higher benefit of surgical compared to medical therapy to reduce the risk of ischemic stroke in case of severe stenosis, (over 70% in NASCET study and over 85% in ECST study) with a Number Needed to Treat, NNT, at 2 years of 8. For moderate stenosis (50–69% in the NASCET study) there was a smaller benefit (NNT = 20), while there was no benefit for stenosis < 50%. The ACAS study on asymptomatic carotid stenosis showed a higher benefit of surgical therapy for stenosis over 60% (NNT at 2 years of 67). The application of these results to clinical practice depends on the reproducibility of the same conditions mainly in terms of perioperative risk. Moreover, data on the natural history of asymptomatic carotid stenosis showed that only 50% of the ischemic events at follow-up were related to the stenosis itself. This could indicate that the real benefit of the surgical procedure could be less than that reported by the clinical trials. The plaque composition, to be evaluated by emerging ultrasonographic and magnetic resonance techniques, is assuming increasing relevance as a further criterion to establish the indication for the surgical procedure. At the moment, however, no evidence exists on this matter.
The usefulness of Time-of-Flight MR angiography in detection of intraplaque hemorrhage in patients with acute ischemic stroke with symptomatic carotid stenosis