SVS Registry Finds Surgery Superior to Stenting in Older Carotid Patients

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In patients aged 65 years and over, carotid artery stenting (CAS) results in 30-day outcomes that are inferior to those achieved with carotid endarterectomy (CEA), according to a study published online March 28, 2012, ahead of print in the Journal of Vascular Surgery. The paper, based on findings derived from a Society for Vascular Surgery (SVS) registry, raises questions about widespread use of CAS in older patients.

Jeffrey Jim, MD, of the Washington University School of Medicine (St. Louis, MO), and colleagues analyzed data from the SVS Vascular Registry. During the study period from July 2005 to December 2010, there were 8,913 patients with 30-day follow-up available for evaluation. In the three-quarters of patients (75.2%) who were at least 65 years old, 62.2% underwent CEA, and 37.8% had CAS. In younger patients, the ratio was 61.0% to 39.0%.

In patients younger than 65 years, the primary composite endpoint of death, stroke, or MI at 30 days was similar between CEA and CAS at 3.56% and 5.23%, respectively (P = 0.065) but favored CEA in the asymptomatic subgroup at 2.10% vs. 4.44% (P < 0.031). But among older patients, CEA performed better than CAS irrespective of symptom status, even after risk adjustment. Differences were driven both by stroke and death rates (table 1).

Table 1. Death/Stroke/MI at 30 Days in Patients ≥ 65 Years

“Although CAS may be preferred over CEA in some situations because of certain medical risk factors or anatomic considerations, [identifying] this subset of patients was beyond the scope of this study,” the researchers conclude. “However, the current available evidence simply does not support the widespread use of CAS.”

Dr. Jim and colleagues do acknowledge several limitations of their study, among them the lack of both anatomic information—such as plaque characteristics, vessel tortuosity, and calcification—and level of operator experience in the SVS registry.

Questions About Methodology

In a telephone interview with TCTMD, William A. Gray, MD, of Columbia University Medical Center (New York, NY), was quick to point out what he viewed as additional flaws.

The registry began in 2005, within months of when the Centers for Medicare and Medicaid Services (CMS) approved coverage of CAS. “That was a very early phase of carotid stenting expansion in this country beyond the clinical trial sites. So they’re taking carotid endarterectomy, something that’s been around for over 50 years, and comparing it to a brand new technique being rolled out into the community,” Dr. Gray noted, suggesting that the SVS registry would inherently attract the participation of surgeons. “So this really reflects surgeons’ performance of carotid stenting.”

Dr. Gray cited possible ascertainment bias—in that neurological assessment is less common with CEA than CAS—and selection bias. Because CEA is the more invasive procedure, the sickest patients are often funneled into CAS. As such, the groups are “horribly mismatched,” he said. “That’s a very subtle thing, but it’s actually very important. There’s this interactive effect of having the option of both stenting and surgery available to you.” In light of this, the study’s lack of propensity matching is a problem, he added.

According to Dr. Gray, the adverse outcomes documented by the registry seem too high to be plausible. “If 1 out of every 10 of my patients who was symptomatic and over the age of 65 had a stroke, death or MI, I would be out of business,” he commented.

Dr. Gray agreed that outcomes are indeed poorer in older than in younger patients but maintained that this is true for both CAS and CEA.

Striving for the Real World

Dr. Gray pointed to CREST, the 2,500-patient randomized trial published in the New England Journal of Medicine in 2010, which found overall equivalence between carotid stenting and surgery.

“Anything less than that is rife with problems,” he said, adding, “I hope this very poorly done, unadjusted, biased . . . paper does not affect the possibility of patients getting access to this technology, because that would be a real shame and a scientific travesty, quite frankly.”

Yet Dr. Jim and coauthor Gregorio A. Sicard, MD, also of the Washington University School of Medicine, said that the SVS registry provides a valuable window into real-world practice patterns.

“Obviously, there’s a lot of data out there from these very structured clinical trials. Everyone sits there debating the efficacy of these 2 procedures. That’s really important in terms of looking initially. But in terms of spreading [CAS] out into the country and expanding coverage, . . . you’ve got to look at effectiveness,” Dr. Jim said. He told TCTMD in a telephone interview that, unfortunately, the registry results do not measure up to what has been documented in the clinical trial setting.

Dr. Jim reported that the SVS dataset represents a “pretty good mix,” with 93 hospitals and 871 physicians reporting their outcomes. Among them were 465 vascular surgeons, more than 100 interventional cardiologists, and other physicians from different subspecialties.

“The driving force for CMS revisiting coverage was the publication of the CREST trial. There’s a lot of focus on it,” he said. “But I think it’s silly to dismiss what happens in the real world, too.” Dr. Sicard pointed out in the same interview that CMS requires operators seeking coverage to participate in reporting outcomes.

Interestingly, outcomes actually appear to be worsening over time, Dr. Jim said, though no formal analyses of the SVS database have been conducted to assess this pattern. Possible culprits include the expansion of CAS to less experienced operators, nonacademic medical centers, and sicker patients, he suggested.

Many Pieces to the Puzzle

Christopher K. Zarins, MD, of Stanford University School of Medicine (Stanford, CA), a surgeon who performs both CAS and CEA, told TCTMD that the SVS registry study provides valuable information.

“I think it shows what goes on in the real world,” he said, noting that the definition of “real” is often debated. “[C]laiming that prospective randomized trials reflect [actual practice] is kind of a stretch because of the very rigid inclusion and exclusion criteria. . . . It’s the nature of the beast, and you learn from everything. Ultimately, when you put all the pieces of all the data sources together you get the closest thing to the real picture.”

The current paper “makes sense, and it reflects what people working in the field know—older people have worse, more complex disease,” Dr. Zarins commented.

In light of the increased stroke risk seen with CAS in CREST, he said, clinicians should be cautious of performing the procedure, particularly in elderly patients. “Stenting’s a good procedure for the right patient, but you’ve got to be selective,” Dr. Zarins concluded. “[For the] standard garden variety, everyday work, all things being equal—if you have an elderly patient, they’re a lot safer having endarterectomy than having a stent.”

Source:

Jim J, Rubin BG, Ricotta III JJ, et al. Society for Vascular Surgery (SVS) Vascular Registry evaluation of comparative effectiveness of carotid revascularization procedures stratified by Medicare age. J Vasc Surg. 2012;Epub ahead of print.

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