Transcranial Doppler Emboli Identifies Asymptomatic Carotid Patients at High Stroke Risk: Why This Technique Should be Used More Widely
With modern intensive medical therapy, the annual risk of ipsilateral stroke in asymptomatic carotid stenosis (ACS) is now ∼0.5%. Therefore, even the relative low risks reported from the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) trial do not justify routine intervention in most (90%) of the patients with ACS. It is therefore necessary to identify the ∼10% to15% of patients with ACS who have a stroke risk high enough to justify intervention. Transcranial Doppler (TCD) embolus detection has been shown in 2 prospective studies (one with 468 patients and the other with 467 patients) to identify patients at high risk and distinguish them from those who would be better served by medical therapy. There is no valid reason why carotid intervention should be carried out in ACS without first identifying that the patient’s risk of stroke is higher than the risk of intervention. The best validated way to do this is by TCD embolus detection, and the cost of TCD equipment and training is approximately the same as the cost of 2 carotid stenting procedures in the United States. This procedure should be used more widely.