Moderate Restenosis More Frequent with Carotid Stenting Than Surgery

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Moderate restenosis is more than twice as common after carotid artery stenting (CAS) than after carotid endarterectomy (CEA), although more severe occlusions occur with equal frequency, according to a subanalysis of the EVA-3S trial published online February 10, 2011, ahead of print in Stroke. The findings, though, show that the increased restenosis does not adversely affect clinical outcomes.

In EVA-3S (Endarterectomy vs. Angioplasty in Patients with Symptomatic Severe Carotid Stenosis), researchers randomized 527 patients to CAS or CEA. The trial, which failed to find CAS noninferior to CEA, was stopped in 2005 for safety reasons stemming from an excess of complications in the stenting arm.

In the new subanalysis, researchers led by Jean-Louis Mas, MD, of Université Paris Descartes (Paris, France), analyzed the carotid ultrasound results of 507 patients from the main trial. At 3 years, moderate restenosis (≥ 50%) was about 2.5 times more prevalent after CAS compared with CEA, while the rates of severe restenosis (≥ 70%) or occlusion were equivalent between the 2 arms (table 1).

Table 1. Restenosis Rates 3 Years After Carotid Revascularization

CAS was estimated to shorten the time to moderate restenosis by 84% compared with CEA. Most cases of restenosis occurred in the first year after the procedure.

Among those who developed restenosis, the majority of cases were recurrent as opposed to residual. The rates of contralateral restenosis ≥ 70% were 19.8% with CAS and 18.5% with CEA (P = 0.96). The only independent predictor of carotid restenosis was age at baseline (P = 0.05). Other baseline characteristics such as female sex, hypertension, diabetes, smoking, antiplatelet therapy, lipid-lowering drug therapy, and closed- vs. open-cell stent design were not predictive.

The occurrence of restenosis, however, had no effect on clinical outcomes, with rates of stroke and stroke or TIA equivalent between those who did and did not develop such blockages (table 2).

Table 2. Clinical Outcomes at 3 Years

In particular, the rate of ipsilateral stroke was 2.6% in the patients with restenosis, while 1% of patients without restenosis developed an ipsilateral stroke by 3 years. Three-year rates of ipsilateral stroke or TIA were 10.3% and 2.6% in the restenosis and no-restenosis groups, respectively.

“The excess rate of restenosis after CAS was attributable to an excess in moderate restenosis, whereas the rates of severe restenosis (≥ 70%) or occlusion [were] low and similar in both treatment groups,” the researchers conclude.

Still, Dr. Mas and colleagues caution that “the proportion of patients with severe restenosis after CAS may increase over time. More data are needed to assess the rates of moderate and severe restenosis over time after CAS . . . to determine the relation between restenosis and recurrent stroke . . . and to assess whether patients treated with endarterectomy or stenting require long-term follow-up with carotid ultrasound to detect restenosis.”

It Just Doesn’t Matter

In a telephone conversation with TCTMD, Christopher J. White, MD, of the Ochsner Clinic Foundation (New Orleans, LA), called the results “much ado about nothing,” since restenosis in the moderate range (50-70%) is clinically unimportant.

“We don’t do anything about a carotid artery unless it’s more than 80% blocked,” Dr. White said. “It really doesn’t matter if the artery has 40% or 60% or 70% restenosis, none of that’s obstructive and none of that is going to cause a problem. In fact, they don’t report any difference in clinical events for all this moderate restenosis.”

Furthermore, such moderate blockages are not going to progress significantly, Dr. White maintained. “We’ve done carotid stenting since 1994 so we’ve followed a lot of patients out to about 16 years, and what we find is they don’t deteriorate,” he said. “They get to a certain point around 1 to 2 years, and they don’t change after that. They’re very stable. So the authors made a big deal out of patients who don’t matter.”

EVA-3S has come under criticism for the relative inexperience of the operators who performed the stenting procedures. This deficiency may have exacerbated the restenosis risk, Dr. White said. In the trial, operators were only required to have performed at least 12 CAS procedures or at least 35 supra-aortic trunk procedures, of which at least 5 were in the carotid artery.

Skills, or Lack Thereof, Key

“The skill factor that EVA-3S didn’t have shows up again in this moderate-restenosis group. This is why there were so many with 50% or 60% or 70%, the operators probably left them with 30% or 40%, as opposed to a good carotid stenter who would leave these guys with 0 or 10%,” Dr. White said. “If you looked at a group of patients like in CREST, for example, they would not have anywhere close to these numbers, because they would all have been more effectively stented.”

He added that while such moderate restenosis is problematic in the coronary arteries, this is not the case in the carotids. “It’s not benign in the heart, you can’t run around with 60% to 70% restenosis in the coronaries without an outcome,” Dr. White said. “The brain is much more forgiving. There’s a lot of room for getting away with things, both surgical and stenting.”

Study Details

A median of 5 carotid duplex ultrasound exams per patient were performed over the 3-year study period. Baseline clinical characteristics of patients in the subanalysis were similar to those of the whole EVA-3S population, with no significant differences between those assigned to CAS and CEA.

 

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Source:
Arquizan C, Trinquart L, Touboul PJ, et al. Restenosis is more frequent after carotid stenting than after endarterectomy: The EVA-3S study. Stroke. 2011;Epub ahead of print.

 

 

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