Despite Risks, Carotid Stenting Increases in Elderly, Women

Nancy A. Melville

December 07, 2017

Despite results from the landmark Carotid Revascularization Endarterectomy vs Stenting Trial (CREST) that show carotid artery stenting is riskier than carotid endarterectomy in the elderly and women, rates of the procedure have increased in both groups, new research shows.

"Despite concerns for higher periprocedural complications with carotid artery stenting in elderly patients, the odds of carotid artery stenting increased in the post-CREST compared with pre-CREST era in patients older than 70 years, including symptomatic women," the authors, led by Amer M. Malik, MD, University of Miami Miller School of Medicine, Florida.

The study was published online December 4 in JAMA Neurology.

"Contrary to Expectations"

CREST included 2502 patients who were followed for 10 years. The results showed no significant differences between revascularization with carotid endarterectomy compared with stenting in primary outcomes of stroke, myocardial infarction, or death. However, patients over age 70 years showed better outcomes with endarterectomy and those under 70 had slightly better outcomes with stenting.

Overall women had an increased risk for periprocedural stroke with stenting compared with those receiving endarterectomy (5.5% vs 2.2%), and the risk was more pronounced in women who were symptomatic (7.5% vs 2.7%; P = .01).

To evaluate how patterns in use of stenting in the at-risk groups changed after the 2010 publication of the study, the authors identified 494,733 patients over age 70 years in the 2007-2014 National Inpatient Sample who were reported as receiving revascularization using International Classification of Disease, Ninth Revision, procedural codes.

While the results showed that overall number of revascularizations per million hospitalizations declined from 2007 (1898) to 2014 (1505; P < .001), the proportion of procedures in symptomatic patients increased by 55% in the same period, from 9.0% in 2007 to 13.9% in 2014 (P < .001).

Despite the increased risks in older patients reported in the CREST trial, the proportion of patients over 70 who received carotid artery stenting increased from 11.9% before the trial (2007 to 2010) to 13.8% after the trial (2011-2014; P = .005), representing a 13% higher odds, after multivariate adjustment (odds ratio [OR], 1.13). The OR for symptomatic women was 1.31.

"Based on the results of CREST, these findings are contrary to expectations," the authors write.

Various factors may explain the results. For instance, many clinicians may not have looked beyond the broader CREST findings of the two approaches having similar efficacy, without considering the subtler treatment effects according to age, sex, or symptomatic status, coauthor Fadar Oliver Otite, MD, from the Department of Neurology, University of Miami Miller School of Medicine, in Florida, told Medscape Medical News.

"[For] many physicians the take-home message from CREST was that there is essentially no difference between carotid artery stenting and carotid endarterectomy, and further attention was not paid to the differences noted in subgroup analysis by age or by sex," he added.

In addition, many may have been more influenced by an earlier trial, the Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial, which compared the two approaches in patients older than age 80 years at high risk for surgery and found no significant differences.

Unpredictable Trends

Rates of carotid artery stenting nearly doubled after the 2005 publication of the SAPPHIRE results, and while they dropped somewhat after subsequent studies showed more favorable outcomes with carotid endarterectomy, the trends, as demonstrated in the current study, have been unpredictable.

Another important factor to consider is the advancement of stenting device technology, which has allowed for increased precision in addressing the challenges in older patients that previously could have contributed to the increased stroke risk associated with stenting. These include altered configurations of the aortic arch, increased plaque length, or vessel tortuosity, the authors note.

However, whether those advances have equalized the risk is unknown, said Dr Otite.

"Stenting may be safer now than it has been in the past, but evidence that they are as good as endarterectomy in the elderly are not available. Clinical trial results comparing current stents to surgery or even best non-operative medical treatment are lacking," he said.

Studies have also shown that physician subspecialty can influence preference for stenting, with cardiologists and interventionalists — who are more likely to manage atherosclerotic diseases in elderly patients —  shown to be more likely to prefer stenting compared with neurologists or surgeons.

Those preferences may logically be passed on to patients, the authors note, and the fact that stenting is less invasive than carotid endarterectomy and can be performed with local anesthesia is likely also an important factor for patients and physicians alike.

Yet another factor that may explain the bump in stenting includes an increase in mechanical thrombectomy for the treatment of acute stroke, as the two procedures can be performed at the same time. In fact, the current study showed an increase in concurrent procedures from 4.2% before CREST to 7.9% after it.

Finally, a closer look at the yearly rates of carotid revascularization in adults older than age 70 years before and after CREST shows a notable decline in stent use in 2014 after increases the previous 4 years, from 14.1% in 2013 to 12.7% in 2014, coinciding with changes in American Heart Association (AHA) guidelines in 2014.

The AHA changes, implemented as a result of CREST, indicated that it is reasonable to consider age when choosing between stenting and endarterectomy. The guidelines also gave a class IIa B recommendation that endarterectomy may be associated with improved outcomes in patients over age 70 compared with stenting, particularly when arterial anatomy is unfavorable for endovascular intervention.

Counterintuitive Increase

In an accompanying editorial, James F. Meschia, MD, from the Mayo Clinic in Jacksonville, Florida, agrees that the advances in technology could indeed be driving the counterintuitive increase in use.

"It is possible that the unexpected apparent enthusiasm for stenting in individuals older than 70 years relates to a perception among stent operators of a lower risk of periprocedural stroke with an evolving technology," Dr Meschia said.

He notes, for instance, that the CREST protocol included use of a type of stent with an open-cell design (RX Acculink, Abbott Vascular) and, when possible, use of its companion distal embolic protection device (RX Accunet).

However, closed-cell stents can result in reduced embolic rates by preventing plaque debris from extruding through the holes in the mesh, although the evidence on the superiority of closed-cell over open-cell design is not strong, he notes.

Other advances in carotid artery stenting, including newer proximal balloon embolic protection systems and transcervical access, may further be reducing risk, he said.

Nevertheless, the downward trend of carotid artery stent use indeed appears to be underway, even if not clearly apparent in the current study.

"The preference for stenting over endarterectomy may have peaked in 2012, and there now appears to be a downward trend in carotid artery stent utilization. Full translation of trial results into practice may take years, particularly when operators need to be persuaded rather than regulated into changing behavior," Dr Meschia writes.

Meanwhile, CREST-2, supported by the National Institute of Neurological Disorders and Stroke, and designed to update evidence for or against stenting or endarterectomy relative to intensive medical therapy, is underway.

Study author Dr Chaturvedi serves on the executive committee of CREST-2 and Asymptomatic Carotid Trial 1. Dr Meschia receives funding from the National Institute of Neurological Disorders and Stroke to perform his duties as co-principal investigator for the CREST-2 Clinical Coordinating Center.

JAMA Neurology. Published online December 4, 2017. Full text, Editorial

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