SOURCE: Brott TG, Calvet D, Howard G, et al; Carotid Stenosis Trialists' Collaboration. Long-term outcomes of stenting and endarterectomy for symptomatic carotid stenosis: A preplanned pooled analysis of individual patient data. Lancet Neurol 2019;18:348-356.

In previous studies, researchers demonstrated that the risk of periprocedural complications, specifically stroke or death, was higher in patients undergoing carotid artery stenting (CAS) compared to carotid endarterectomy (CEA) for treatment of high-grade symptomatic carotid stenosis greater than 70%. However, the long-term consequences are not known. Brott et al attempted to evaluate the long-term efficacy of these procedures by doing a pooled analysis of four large, randomized, controlled trials designed to assess the relative efficacy of CAS vs. CEA for treatment of symptomatic carotid artery stenosis. Individual patient data were pooled from the following four studies: Endarterectomy versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis trial, Stent-Protected Percutaneous Angioplasty of the Carotid Artery versus Endarterectomy trial, the International Carotid Stenting Study, and Carotid Revascularization Endarterectomy versus Stenting trial. (Mas JL, et al. N Engl J Med 2006;355:1660-1671. Space Collaborative Group; Ringleb PA, et al. Lancet 2006;368:1239-1247. Bonati LH, et al. Lancet 2015;385:529-538. Brott TG, et al. N Engl J Med 2010;363:11-23.).

The risk of ischemic stroke was assessed starting at 121 days’ postprocedure and then at one, three, five, seven, nine, and 10 years after  randomization. The primary outcome was a composite risk of stroke or death within 120 days (periprocedure risk) or subsequent stroke that occurred up to 10 years after randomization (postprocedural risk). In the four trials, 4,775 patients were randomly assigned and 99.6% were followed for up to a maximum of 12.4 years. The median length of follow-up across all the studies ranged from two to 6.9 years. One hundred twenty-nine periprocedural events occurred in patients who underwent CEA, and 206 events occurred in those allocated to CAS. This confirms what has been shown in other studies — that periprocedural risk is higher in patients undergoing CAS. Long-term follow-up showed a similar number of ischemic strokes occurring in each group: 57 for those allocated to CAS and 55 in those undergoing CEA. The annual rates of ischemic stroke per person-year were similar in both treatment groups, but the addition of periprocedural risk favored carotid endarterectomy.

If periprocedural risk can be reduced in stenting procedures, then both procedures should be approximately equal in efficacy and longer-term durability. In addition, comorbidities, such as continuing to smoke cigarettes, hypercholesterolemia, and contralateral carotid stenosis all contributed to increasing morbidities. These factors should be assessed in future studies.