Endarterectomy, Stenting, or Neither for Asymptomatic Carotid-Artery Stenosis.

Important data from two large, randomized trials comparing early and late outcomes after carotid endarterectomy and carotid-artery stenting have now been published in the Journal.1,2 In common with every other large, multicenter, randomized trial to date, the Asymptomatic Carotid Trial (ACT I) and the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) showed that after the perioperative period, there was no difference in the rate of late ipsilateral stroke after endarterectomy or stenting. In ACT I, which included asymptomatic patients who were deemed to be at average risk, the 5-year rate of ipsilateral stroke (excluding the perioperative period) was 2.2% after stenting (i.e., 0.4% per year) and 2.7% after endarterectomy (0.5% per year).1 In CREST, which included symptomatic and asymptomatic patients who were deemed to be at average risk, the estimated 10-year rate of ipsilateral stroke (excluding the perioperative period) was 6.9% after stenting (i.e., 0.7% per year) and 5.6% (0.6% per year) after endarterectomy.2 The fact that there is near-unanimous consensus within randomized trials that after the perioperative period the rates of late ipsilateral stroke after stenting do not differ significantly from those after endarterectomy should dispel any lingering concerns about the durability of stenting. That issue has now surely been resolved. What has not been resolved, however, is the issue of the generalizability of randomized-trial findings into routine clinical practice, and, more importantly, the vexed question of how best to treat the asymptomatic patient. No one should harbor any illusions that ACT I and CREST have resolved the latter issue. CREST and ACT I both used credentialing to ensure that only the best interventionists and surgeons performed stenting or endarterectomy within the trials. The commendably low rates of death and stroke during the procedure in ACT I and CREST attest to this. It therefore remains to be seen whether these findings can be translated into routine clinical practice, if guidelines are changed to further liberalize indications for stenting, especially in asymptomatic patients. This is an important point, because a recent systematic review showed that 9 of 21 large administrative data-set registries (43%) reported rates of death and stroke in excess of the 3% risk threshold that is recommended by the American Heart Association in asymptomatic patients undergoing stenting, as compared with 1 of 21 registries (5%) after endarterectomy.3 Furthermore, the 3% risk threshold is clearly too high, given the reduction of risk with intensive medical therapy. Discrepancies between randomizedtrial data (i.e., from ACT I and CREST) and realworld practice are nothing new and, in this case, are probably attributable to the fact that many real-world practitioners in the United States are performing two or fewer procedures annually in asymptomatic patients, with poorer outcomes than their more experienced colleagues.4 The magnitude of the initial procedural risk will ultimately determine whether endarterectomy or stenting is preferable in recently symptomatic patients, and this will be determined by recency of symptoms, age of the patient, and coexisting conditions. However, there is a major concern that the data from these two trials will be uncritically interpreted to mean that stenting is equivalent to endarterectomy and so further exacerbate the situation in the United States, where more than 90% of carotid-artery interventions are performed in asymptomatic patients,