Technical, Anatomic Factors Could Aid Patient Selection for Carotid Stenting

Increased internal carotid artery angulation and left sided carotid stenting (CAS) are associated with a higher risk of stroke or death at 30 days, while cerebral protection devices are associated with lower risk, according to an analysis of the EVA-3S trial and a systematic literature review. The results, published online December 23, 2010, ahead of print in Stroke, may help refine patient selection in CAS procedures, the authors note.

Researchers led by Jean-Louis Mas, MD, of Université Paris Descartes (Paris, France), analyzed the aortic arch and carotid arteries on angiography in 262 patients from the EVA-3S (Endarterectomy versus Stenting in Patients with Symptomatic Severe Carotid Stenosis) trial who received CAS. The multicenter randomized EVA-3S trial, which did not find CAS noninferior to endarterectomy, was stopped in 2005 for safety reasons stemming from an excess of complications in the stenting arm. Dr. Mas and colleagues also reviewed 56 published studies on complications of CAS from the literature involving 34,398 patients.

Angulation, Left Sided Stenting Increase Risk

In EVA-3S, there were 25 cases of stroke or death within 30 days of stenting (9.5%). The stroke rate during this time period was 9.2%, with 2 deaths. There were 2 factors in EVA-3S found to influence the risk of stroke or death at 30 days: angulation ≥ 60 degrees in the internal carotid artery-common carotid artery (RR 4.96; 95% CI 2.29-10.74) and cerebral protection devices (RR 0.38; 95% CI 0.17-0.85), which decreased risk. Cerebral protection also was associated with a lower risk of stroke or death within 24 hours and a lower risk of stroke alone. Factors associated with nonsignificant trends for increased 30-day stroke and death included type III aortic arch, subpetrous internal carotid artery tortuosity, and calcification or ostial involvement.

Factors found to have no influence on stroke or death included type of stent (closed- or open-cell), type of cerebral protection (filter or balloon), type of filter, and procedure duration (> 50 minutes vs. ≤ 50 minutes). All of the results remained consistent after adjustment for age and sex.

The literature review, which included the EVA-3S results, also found 30-day stroke or death to be higher in patients with increased internal carotid artery-common carotid artery angulation (RR 3.41; 95% CI 1.52-7.63). Meanwhile, left sided CAS (RR 1.29; 95% CI 1.05-1.58) also increased risk, while cerebral protection, as in EVA-3S (RR 0.55; 95% CI 0.41-0.73), lowered risk. In addition, patients with internal carotid artery stenosis longer than 10 mm (RR 2.59; 95% CI 1.10-6.60) or showing calcification (RR 1.67; 95% CI 1.02-2.72) had a higher risk of 30-day stroke.

“[O]ur analysis from EVA-3S data and an updated systematic review of the literature show that aortic arch and proximal carotid artery anatomy and the characteristics of the stenosis itself could . . . influence the 30-day risk of stroke or death,” the researchers conclude. “These characteristics, together with [previously identified] clinical risk predictors, may help select good candidates for CAS in future trials and eventually in clinical practice.”

They caution, though, that the ability of cerebral protection devices to lower the risk of stroke or death should be tested in randomized trials.

Impact of Angulation

In a telephone interview with TCTMD, Michael R. Jaff, DO, of Massachusetts General Hospital (Boston, MA), indicated he was surprised that factors such as type III arch and calcification of the lesion did not have an impact on 30-day death or stroke. Meanwhile, the new information from the study, in his view, was the finding regarding artery angulation.

“I think most people would say a severely angulated carotid lesion should not be considered for carotid stenting, but not necessarily because it could increase stroke risk, but rather because it’s harder to deploy the stent,” Dr. Jaff said. “This study shows that not only does it make the procedure harder, angulation increases the risk of stroke or death, and that’s something I didn’t know. I think this finding would have an impact.”

‘Color of the Carpeting’

William A. Gray, MD, of Columbia University Medical Center (New York, NY), agreed that the angulation data represent a new finding. However, he took issue with the overall significance of the study, due to the high rate of complications in EVA-3S and the inexperience of the operators.

In the trial, interventional physicians were only required to have performed at least 12 CAS procedures or at least 35 stenting procedures of the supra-aortic trunks, of which at least 5 were in the carotid artery.

”This study is like seeing a horrific car accident . . . and doing an analysis as to whether the color of the carpeting of the car made a difference,” Dr. Gray told TCTMD in a telephone interview.

Value of Data Debated

Dr. Jaff agreed that EVA-3S has been heavily criticized for utilizing inexperienced operators. “But having said that, I don’t think it does damage to the procedure by saying you ought to think twice about an acutely angulated internal carotid artery,” he said. “Certainly the message for the less experienced operator is this is an important factor, one that’s probably just as important as a calcified lesion.”

Dr. Gray, however, disagreed. “I would put a different spin on this, which is: If you don’t have the right experience, you should have somebody in the room who does,” he said. “There are enough operators in the United States today that you don’t have to be getting your experience solo at the expense of the patient.”

Cowboys No Longer

Dr. Gray added that the predictors identified in the study may have held value during the time period of EVA-3S (2000-2005) among operators with little experience. “However, it’s harder to relate that assessment to any reasonably efficient practicing doctor,” he stressed.

Dr. Jaff agreed that patient selection and experience have changed drastically since the early days of carotid stenting. “The learning curve is clear,” he said. “Back in the SAPPHIRE days (2000-2002), only [a very few] patients were deemed not suitable for carotid stenting, where over 100 were deemed not suitable for endarterectomy. At the time, people said ‘look at how chicken these surgeons are,’ but in fact it turned out that the interventionalists were probably too cowboy-ish, and they chose lesions that would be better suited for endarterectomy.”

When the time period is combined with the operator experience of EVA-3S, “the generalizability of the findings is in question,” Dr. Gray said.

Study Details

Two independent radiologists blinded to clinical data retrospectively reviewed all available films of digital subtraction angiograms obtained before CAS and immediately after stent placement. An angiogram of the target stenosis was available in all patients.

 

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Source:
Naggara O, Touzé E, Beyssen B, et al. Anatomical and technical factors associated with stroke or death during carotid angioplasty and stenting: Results from the Endarterectomy versus Angioplasty in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial and systematic review. Stroke. 2010;Epub ahead of print.

 

 

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