Rule Can Help Distinguish Between Patients Who Need Carotid Stenting vs. Surgery

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A simple rule incorporating clinical risk factors may help clinicians choose between carotid artery stenting (CAS) and carotid endarterectomy (CEA) for patients with severe symptomatic carotid stenosis, according to a study appearing online October 17, 2013, ahead of print in Stroke.

Emmanuel Touzé, MD, PhD, of the Caen University (Caen, France), and colleagues systematically reviewed 170 observational studies looking at procedural risks of CEA or CAS and extracted data on 9 predefined risk factors (age, contralateral carotid occlusion, CAD, diabetes, sex, hypertension, PAD, and type and side of stenosis). Relative risks of procedural stroke or death were pooled, and the risk factors with the greatest effect on those outcomes were identified.

Among the 9 risk factors, age was associated with higher risks of procedural stroke or death for both CAS and CEA but the increase in risk was greater after CAS. Contralateral occlusion and female sex were associated with a higher risk of procedural stroke or death after CEA but had no significant influence on risk after CAS. Compared with patients with primary atherosclerotic disease, those with restenosis after CEA had a higher risk of procedural stroke or death when treated by CEA but a lower risk when treated by CAS.

Thus, 4 factors emerged as most important and these were the basis for the clinical rule termed by the investigators as SCAR (Sex, Contralateral occlusion, Age, and Restenosis).

‘SCAR-Positive’ Patients at Higher Risk

To validate the proposed rule, the researchers then pooled patient data from 3 large European randomized trials (EVA-3S, SPACE, and ICSS) to form the Carotid Stenting Trialists’ Collaboration (CSTC).

Of 3,049 CSTC patients, 22.8% were classified as SCAR negative, meaning they had contralateral carotid occlusion or restenosis or were female and less than 75 years of age. Among these SCAR-negative patients, the absolute risk of any stroke or death was identical between CAS and CEA at 5.6%. However, among SCAR-positive patients, CAS more than doubled the risk compared with CEA (8.4% vs. 3.5%).

Additionally, SCAR-positive patients were at much higher relative risk of procedural stroke and death with CAS vs. CEA, while SCAR-negative patients were not (table 1).

Table 1. Risk of Stroke and Death by SCAR Status: CAS vs. CEA

Similar results were seen in analyses of the individual endpoints and in a sensitivity analysis considering all 4 risk factors as equivalent. An additional sensitivity analysis including only patients who were SCAR positive and aged less than 70 years also showed a trend toward greater procedural risk of stroke or death with CAS compared with CEA (RR 1.77; 95% CI 0.98-3.21).

In the absence of contralateral occlusion and restenosis, only women aged less than 75 years were identified as having lower risk with CAS by the SCAR rule, consistent with the finding that men aged less than 75 years without contralateral carotid occlusion remained at higher risk of procedural stroke or death when treated by CAS vs. CEA (RR 1.94; 95% CI 1.22-3.07).

CAS Emerges as Lowest Risk Option for Women

“By pooling all available data, we have confirmed that women are at higher risk of procedural stroke or death after CEA and shown that there is no evidence of an increased risk of periprocedural stroke or death after CAS, the risk being slightly higher in men,” the study authors write. They say the sex difference mainly results from a higher risk of periprocedural complications after CEA in women, which has been attributed to differences in carotid size and in the nature of the atheromatous plaque.

The results are contrary to a recent analysis of data from the CREST trial suggesting that women have a higher risk of periprocedural stroke or death after CAS than men (5.5% vs. 3.7%), but Dr. Touzé and colleagues say the treatment-by-sex interaction from CREST was not significant. Nor are the results consistent with other trial data or case series.

The study authors caution that while the rule can already be considered useful for clinical practice, further refinement is required.

 

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Source:
Touzé E, Trinquart L, Felgueiras R, et al. A clinical rule (sex, contralateral occlusion, age, and restenosis) to select patients for stenting versus carotid endarterectomy: Systematic review of observational studies with validation in randomized trials. Stroke. 2013;Epub ahead of print.

 

 

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