Carotid Stenting vs. Endarterectomy for Symptomatic Stenosis: Endarterectomy Remains the Gold Standard
December 1, 2009 5 minutes read
Carotid Stenting vs. Endarterectomy for Symptomatic Stenosis: Endarterectomy Remains the Gold Standard
Abstract & Commentary
By Matthew E. Fink, MD, Interim Chair and Neurologist-in-Chief, Department of Neurology and Neuroscience, Weill Cornell Medical College, New York Presbyterian Hospital. Dr. Fink reports no financial relationships relevant to this field of study.
Synopsis: At the present time, carotid endarterectomy remains the treatment of choice for severe carotid artery stenosis, until additional evidence emerges from ongoing randomized clinical trials.
Sources: Ederle J, et al. Endovascular treatment with angioplasty or stenting versus endarterectomy in patients with carotid artery stenosis in the Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS): Long-term follow-up of a randomized trial. Lancet Neurology 2009;8:898-907. Bonati LH, et al. Long-term risk of carotid restenosis in patients randomly assigned to endovascular treatment or endarterectomy in the Carotid and Vertebral Transluminal Angioplasty Study (CAVATAS): Long-term follow-up of a randomized trial. Lancet Neurology 2009;8:908-917.
Carotid artery angioplasty and stenting (CAS) burst upon the scene about 15 years ago and quickly became popular with endovascular specialists in cardiology, vascular surgery, neurosurgery, interventional radiology, interventional neuroradiology, and neurology. As so often happens with a new technique, CAS became a widespread treatment for carotid stenosis, both symptomatic and asymptomatic, even without appropriate randomized, clinical trials to demonstrate its safety and efficacy. And because of widespread publicity, many patients with carotid artery stenosis arrived at their neurologists' offices saying, "I want to be treated with a stent." To the credit of the investigators in the U.K. and Europe, The Carotid And Vertebral Artery Transluminal Angioplasty Study (CAVATAS) was started with the randomization of the first patients in 1992, and that allowed the investigators to report on the long-term results of CAS, compared to carotid endarterectomy (CEA), a tested and proven treatment for both symptomatic and asymptomatic carotid artery stenosis.
In 2001, the CAVATAS investigators reported on the peri-operative safety outcomes at 30 days, and revealed that there were similar rates of major complications compared to carotid endarterectomy (CEA), stroke lasting more than seven days or death, but the rates in both arms were unacceptably high (around 10%) and mandated additional comparative trials. Two other completed trials, EVA-3S and SPACE, did not establish the equivalence of CAS with CEA in terms of early safety (Lancet Neurology 2008;7:893-902,885-892) at 30 days, and the Cochrane Database meta-analysis (2007:4:CD000515) did not support a change in clinical practice away from CEA.
In the current reports, the CAVATAS investigators evaluated 504 patients (90% symptomatic) who were randomly assigned to CAS or CEA and followed for a median length of five years (R=2-6). Comparing endovascular treatment to CEA after the 30 day peri-operative period, the eight-year incidence and hazard ratio (HR) for ipsilateral stroke was 11.3% vs. 8.6% (HR = 1.22, 95% CI 0.59-2.54), for ipsilateral stroke or TIA was 19.3% vs. 17.2% (HR=1.29, CI 0.78-2.14), and any stroke after 30 days was 21.1% vs. 15.4% (HR=1.66, CI 0.99-2.80). Although there were more long-term strokes and TIAs in the endovascular group compared with CEA, these differences did not reach statistical significance. In addition, CAVATAS has a major limitation, in that most of the patients who underwent endovascular therapy had angioplasty alone, not angioplasty with stenting. Modern therapy includes stenting with use of an embolism protection device, making the CAVATAS data interesting but not definitive regarding endovascular therapies.
In a companion article, the CAVATAS investigators reported on the long-term risk of carotid restenosis in patients who were treated with CAS compared to those treated with CEA. Four-hundred thirteen (413) patients were randomized and followed for a median of five years, with carotid duplex ultrasound performed at a median of four years. Severe carotid restenosis (≥ 70%) or occlusion occurred more often in patients with endovascular therapy than in patients with CEA, and the differences were significant (HR=3.17, 95% CI 1.89-5.32: p<0.0001). The estimated five-year incidence of restenosis was 30.7% in the CAS arm and 10.5% in the CEA arm. It is very important to note in CAVATAS that of the 200 patients followed after endovascular therapy, 150 had angioplasty alone, and 50 were treated with a stent. Patients treated with a stent had a lower risk of developing restenosis than those with angioplasty alone. Smoking, currently or in the past, was a powerful risk factor in predicting restenosis of 70% or more (HR=2.32, CI 1.79-4.54, p=0.01). The risk of long-term stroke and TIA was higher in those patients who developed restenosis of 70% or more within the first year after treatment.
Commentary
CAVATAS is an important study, because it is one of the few randomized clinical trials of endovascular therapy for carotid artery stenosis that was a comparison to CEA, early in the use of angioplasty and stenting. For that reason, it is one of the few studies that has long-term data (at least five years). Even though CAVATAS used a "primitive" form of endovascular therapy, it is clear from the results that endovascular therapy was not proven "non-inferior" to CEA and CEA remains the "gold standard" to which other therapies must be compared.
At the present time, there is no statistically valid data to support the use of CAS in symptomatic carotid artery stenosis except in patients who are poor or high-risk surgical candidates. That category includes restenosis after CEA, radiation-induced carotid stenosis, anatomically high lesions, and high risk from multiple medical co-morbidities. One could make the point that high medical risk would argue against any surgical intervention, and would favor aggressive medical therapy. During the course of the CAVATAS study, aggressive use of statins and newer antiplatelet therapies were not available. One could argue that current medical therapy would have a better long-term result.
So where to we go from here? There are two clinical trials that we await with great excitement and anticipation-the International Carotid Stenting Study (ICSS) from Europe, and the Carotid Revascularization Endarterectomy versus Stent Trial (CREST)-both which expect to report their results in early 2010. The CREST trial, in particular, has been designed with scrupulous credentialing of both endovascular and surgical specialists to ensure high-quality outcomes. Stenting was performed with the use of embolism prevention devices. CREST has been powered to detect clinically significant differences between the two procedures, and includes both symptomatic and asymptomatic patients. So, until the long-term results of ICSS and CREST are released, we do not have any evidence to support the use of endovascular therapies for severe carotid stenosis, unless the patient is not able to safely undergo endarterectomy.
At the present time, carotid endarterectomy remains the treatment of choice for severe carotid artery stenosis, until additional evidence emerges from ongoing randomized clinical trials.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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