Selection of Patients for Carotid Endarterectomy versus Carotid Artery Stenting


Carotid endarterectomy (CEA) has been shown to decrease the long-term risk of stroke compared with medical therapy. Percutaneous techniques such as carotid artery angioplasty with stenting (CAS) are less invasive and a viable option for the treatment of carotid artery disease.

The increased use of CAS to treat carotid artery disease has been questioned, mainly by the surgical community, because of the perceived superiority of CEA. This has led to a contentious debate between those with opposing views of the new technology. The proponents of CAS have attempted to demonstrate its noninferiority compared with CEA with the main purpose of expanding indications and reimbursement for the procedure. On the other hand, those who questioned the efficacy of CAS expected that randomized trials would confirm the superiority of one procedure over the other and elucidate the indication for either procedure in the different clinical settings.

After multiple major trials and registries implemented to establish the validity of CAS compared with CEA, there is still no consensus on whether there is equipoise between both treatment options for carotid artery disease. This is well illustrated by the diverging recommendations for the treatment of carotid artery disease given by the different professional organizations that claim expertise on this subject. We argue that it is premature to give a final evaluation to CAS. Contrary to what pundits on both sides of the issue appear to believe, CAS is still in its developmental stage and remains in evolution.

Currently, there is no question that CEA, in the appropriate hands, remains the best option for treating carotid artery disease under most circumstances. However, there is no doubt that the safety and efficacy of CAS, in its current form, is acceptable in some clinical situations and that many patients have and will benefit from it. The question is when CAS should be used instead of CEA.

The vast amount of comparative data accumulated on the matter shows modest differences in the neurologic complication rates in favor CEA. It is important to remember that recent data evaluate the results with a specific technique and technology of CAS. The future of CAS, however, cannot be judged based on past trials, because it is unavoidable that data become obsolete as the technology and technique for CAS evolves. The actual performance of CAS has been remarkably good in terms of recurrence of stenosis rate and long-term stent-related complications when compared with CEA.

The differences in neurologic complication and death rates between CAS and CEA reported in major trials are based on a standardized technique for CAS using the transfemoral approach and using distal filters for cerebral protection in most instances. These two technical aspects of CAS, the transfemoral access and distal filter protection, are unrelated to the stent itself, but they are responsible for the majority of the neurologic complications attributable to CAS. Based on the small differences in neurologic complication rates between CAS and CEA, it is possible that a reduction in the embolic phenomena associated with CAS could yield neurologic complication rates comparable, or perhaps superior, to those of CEA in certain cases. Given the limitations of the available information, an analysis of current data comparing CAS with CEA is warranted.

Carotid Stenting Versus Endarterectomy: Major Trial Data

The highest-quality data accrued on the comparison of CAS with CEA is based on a small number of well-conducted randomized trials that have been completed during the last few years. However, selecting the ideal patient population who may be best treated with CAS remains difficult. Data from four trials conducted with perhaps the best methodology and lack of bias deserve discussion.

The CREST study, a randomized trial designed to compare the efficacy of stenting in patients with average surgical risk, was completed in 2008. It included 2502 patients, 53% of whom were symptomatic, with a statistical power to detect small differences between CAS and CEA. The trial’s primary endpoint was the combined incidence of stroke, myocardial infarction (MI), and death from any cause. Secondary endpoints included incidence of restenosis, post-procedure morbidity, quality of life, cost effectiveness, and outcomes among different subgroups considered at high risk. To compare the best possible stenting with the best quality surgery, the CREST trial included a strict accreditation phase designed to eliminate the learning curve associated with the interventional technique for CAS and to select surgeons with a documented low complication rate with CEA.

At a median of 2.5 years of follow-up, the incidence of the composite endpoint of death, MI, and stroke was not different between CAS and CEA (7.2% vs. 6.8%; hazard ratio [HR], 1.11; p = .51), with no difference in the treatment effect based on symptomatic status or gender. The lack of difference in the composite primary endpoint between the two groups was mainly produced by the higher incidence of MI in the endarterectomy group (1.1% vs. 2.3%; p = .03). On the other hand, the incidence of any stroke within 30 days after the procedure was significantly higher in the CAS group (4.1% vs. 2.3%; p = .01), but there was no difference in the incidence of major stroke between the groups (0.9% for CAS vs. 0.7% for CEA).

An important finding of the CREST trial was that the impact on quality of life at 1 year of intervention was greatly reduced in patients with major or minor stroke but not in those with MI. This may be caused by the use of biomarkers in the diagnosis of myocardial ischemia that included many myocardial events of questionable clinical significance, inflating the incidence of MI. The difference in incidence of MI between CREST and other trials is particularly striking when compared with the International Carotid Stenting Study (ICSS) published in Lancet in 2010, in which there was no difference in the incidence in MI rates (0.35% for CAS vs. 0.46% for CEA), but with a greater fatality for MI on the CAS group.

Consistent with previous trials, age appeared to influence treatment outcomes. In CREST, there was a slight difference in outcomes at 4 years of follow-up, with patients older than 70 years faring better with CEA, and patients younger than 70 years faring better with CAS.

The EVA-3S, SPACE, and ICSS trials were conducted in France, Germany, and Great Britain, respectively, and their results were published between 2006 and 2010. These three trials included only patients with symptomatic carotid artery disease. Proponents of CAS criticized the requirements of these three trials for qualification of physicians to conduct carotid intervention. They argued that the experience of those performing carotid stenting in these trials was insufficient, and that the higher neurologic complication rates of CAS compared with CEA reflected in the trials was a result of interventional inexperience. Although the small numbers of CAS procedures required for trial participation was in our opinion a genuine concern, there was no difference in neurologic complication rates between the experienced and inexperienced interventionalists participating in those trials, and therefore inexperience did not appear to be the reason for the difference in results.

In the EVA-3S trial, at 4 years of follow-up, the cumulative probability of procedural stroke or death and nonprocedural stroke was higher in the CAS group (11.1 vs. 6.2; p = .03). However, this difference was derived mainly from the 30-day periprocedural complication rates, and after that period the risk of ipsilateral stroke was equivalently low for both procedures.

The SPACE trial, at 2 years of follow-up, found no significant difference in the incidence of the composite endpoint of ipsilateral stroke and periprocedural stroke or death between CAS and CEA (9.5% vs. 8.8%; p = .31). During follow-up, the incidence of greater than 70% recurrent stenosis, as assessed by ultrasound, was significantly higher with CAS (10.7% vs. 4.6%; p = .0007), but there was no modification in velocity criteria used for the assessment of intrastent stenosis. Therefore, it is likely that the stent restenosis rate was overestimated.

Finally, the ICSS trial early results published in 2011 revealed a higher incidence of the combined endpoint of stroke, death, and MI at 4 months from randomization in the CAS group compared with CEA (8.5% vs. 5.2; p = .006). Interestingly, and in contradiction to the CREST trial, the ICSS trial found no difference in the incidence of MI between the two treatment groups, but there were three deaths from MI in the CAS group, whereas no cardiac-related deaths occurred in patients treated with CEA.

A preplanned meta-analysis of the early results (120 days from inclusion in the trial) of these three trials including a total of 3433 patients found that the incidence of any stroke or death in patients undergoing CAS was significantly higher than that for CEA (8.9% vs. 5.8%; p = .0006). This meta-analysis suggested that the difference in early outcomes is derived from the twofold higher rate of complications for CAS that occurred in patients 70 years of age or older, compared with those undergoing CEA in the same age group (12% vs. 5.9%; p = .0053). The meta-analysis found no difference in the risk of stroke or death between CAS and CEA in patients younger than 70 years.

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