Carotid Surgery Bests Stenting in Older Asymptomatic Patients

Mitchel L. Zoler

February 24, 2020

LOS ANGELES — Carotid artery stenting in older, asymptomatic patients with severe carotid artery stenosis is, in general, as bad an idea as it has already proven to be in symptomatic patients, with a multifold increase in adverse short- and mid-term outcomes, compared with similar patients who underwent endarterectomy, according to a combined-study analysis with more than 2,500 patients. 

Dr Jenifer Voeks

The risk for poor outcomes in patients with severe but asymptomatic carotid artery disease who underwent carotid artery stenting (CAS), compared with patients who instead underwent carotid endarterectomy (CEA) "abruptly increased around age 75," in an analysis that combined data from the two major, published, randomized trials that compared these two interventions in this patient population, Jenifer H. Voeks, PhD, said here at the International Stroke Conference sponsored by the American Stroke Association/American Heart Association.

These results "largely mirror" the findings from a similar combined analysis of data from four major, randomized trials that compared CEA and CAS in patients with symptomatic carotid disease, she noted.

The new findings in an expanded population of asymptomatic patients derived from two separate studies showed that, in patients aged 70 years or less, "CAS appears to be a reasonable alternative to CEA, but above age 70, and certainly above age 75, age-related risk factors such as cerebrovascular anatomy and underlying cerebral pathology should be carefully considered before selecting patients for CAS," said Voeks, a neurology researcher at the Medical University of South Carolina, Charleston.

Many experts also believe that, for asymptomatic patients, intensive medical management may have returned as an alternative to either of these invasive approaches for treating severe carotid stenosis and has achieved a level of equipoise that led to the launch of CREST 2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial). CREST 2 is comparing CEA and CAS with medical management, and is scheduled to report results in 2021.

The data for this analysis in asymptomatic patients came from the first Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST), which included 1,181 asymptomatic patients (nearly half the total enrollment, with symptomatic patients making up the balance) and had no age ceiling, as well as all 1,453 patients from the ACT 1 trial, which enrolled exclusively asymptomatic patients with enrollment limited to patients aged 79 years or less.

Because the maximum age of patients in ACT 1 was 79 years, for this analysis, the researchers only included the 1,091 asymptomatic CREST patients who also were below the same age ceiling. The resulting cohort of 2,544 included 1,637 patients who underwent CAS and 907 who underwent CEA (because of a 3:1 randomization ratio in ACT 1), creating the largest data set to compare CAS and CEA by age in asymptomatic patients, Voeks noted. When subdivided by age, 30% of the cohort was younger than 65 years, 54% were 65-74, and 16% were 75-79.

The primary outcome the researchers used for their analysis was the combined incidence of periprocedural stroke, MI, or death, plus the incidence of ipsilateral stroke during 4 years of follow-up post procedure. Among patients who underwent CAS, this outcome occurred in roughly 9% of patients aged 75-79 years and in about 3% of those younger than 65 years, a hazard ratio of 2.9 that was statistically significant.

In contrast, the incidence of the primary outcome among patients aged 65-74 years was just 30% higher, compared with patients aged less than 65 years, a difference that was not statistically significant.

Patients who underwent CEA showed no similar relationship between age and outcome. The incidence of the primary outcome among the CEA patients was roughly the same, about 3.5%, regardless of their age.

A second analysis that considered age as a continuous variable showed a sharply spiked increase in the risk for CAS patients, compared with CEA patients once they reached about age 73-75 years. Until about age 72, the rate of the primary outcome was nearly the same regardless of whether patients underwent CAS or CEA, but the risk for adverse outcomes rose "steeply" starting at about age 75 so that by age 79 the rate of the primary outcome approached 300% higher among the CAS patients compared with CEA patients, Voeks said.

She cautioned that the analysis included just 115 total primary-outcome events, which makes the incidence rate estimates somewhat imprecise, and that the data reflect outcomes in patients who were treated more than a decade ago, but these data remain the only reported results from large randomized trials that compared CAS and CEA in asymptomatic patients.

Endarterectomy vs Stenting Ignores the Medical Option

The role for carotid intervention in asymptomatic patients with severe carotid stenosis is currently "highly controversial" because intensive medical management has not been compared with invasive treatments such as carotid endarterectomy and stenting for well over a decade, said Mai N. Nguyen-Huynh, MD, a vascular neurologist with Kaiser Permanente Northern California in Oakland, when asked to comment on the findings.

Dr Mai Nguyen-Huynh

New drugs and new regimens have become treatment options for patients with advanced atherosclerotic carotid artery disease, and this has returned the field to a state of "equipoise" for medical vs interventional management, she said in an interview, leading in turn to the launch of CREST 2, comparing medical treatment against endarterectomy and against carotid stenting. 

It's "not surprising" that CEA outperformed CAS in this pooled analysis, Nguyen-Huynh said. There is already evidence that CAS does not perform as well as CEA in older patients with symptomatic carotid artery disease, likely because older patients have more "fragile and torturous blood vessels" that make CAS more challenging and raise the potential for more adverse events.

These new data reported by Voeks et al "should make people pause" when considering CAS for asymptomatic patients who are age 70 years or older. Until new studies collect more contemporary data, medical management is another reasonable option, she noted.

The new findings are very important for helping patients and their families make informed decisions. CAS is often perceived as the safer option for older patients because it is less traumatic and invasive than CEA, she added. "A lot of older patients opt for CAS; these data suggest that may be the wrong decision."

These new results show once again that this intuitive impression about CAS in the elderly is belied by the evidence, she concluded, although the findings also require cautious interpretation because they came from a post hoc, subgroup analysis.

Voeks and Nguyen-Huynh have disclosed no relevant financial relationships.

International Stroke Conference (ISC) 2020: Abstract #70. Presented February 20, 2020.

This story originally appeared on MDedge.com.

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