In a move that makes percutaneous intervention available to the great majority of patients with significant carotid disease, the US Food and Drug Administration (FDA) recently approved expanded use of carotid artery stenting (CAS) with the Rx Acculink stenting system in those at standard risk for adverse events from carotid surgery. Previously, CAS was indicated only for patients at high surgical risk. Rx Acculink was first approved in 2004.

All CAS candidates also must have a reference vessel diameter between 4.0 and 9.0 mm at the target lesion and either neurological symptoms plus at least 50% stenosis by angiography, or no symptoms and at least 60% stenosis by angiography.

Final approval of the new indication, announced May 6, 2011, came a little more than 3 months after a Circulatory System Devices Panel recommended the change in a 7-to-3 vote this past January 26. The expert panel considered data from the multicenter randomized Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST; Brott TJ, et al. N Engl J Med. 2010;363:11-23), which found no difference between the revascularization strategies in long-term safety and efficacy but a higher rate of periprocedural stroke with CAS and a higher rate of periprocedural MI with endarterectomy.  

Post-Market Study Mandated

As a condition of the expanded approval, the FDA will require the manufacturer, Abbott Vascular (Santa Clara, CA), to follow patients for at least 3 years as part of an expanded registry study. The study will also assess how patients age 80 or older respond to CAS and whether outcomes are affected by operator experience. In a telephone interview with TCTMD, William A. Gray, MD, of Columbia University Medical Center (New York, NY), said that provision is important, but it is likely to confirm the CREST results. In addition, he noted, operator experience is already known to influence outcomes. As for age, he reported that a subanalysis of CREST (currently being readied for publication) shows that although older patients have worse outcomes, the increase in complications is similar for both treatments.   

It was a good bet that the FDA would follow the advisory panel’s recommendation regarding standard-risk patients, Dr. Gray said, but in the meantime “most clinicians were fairly respectful of the fact that [CAS] was not approved for that indication.” Now this large population, which represents about two-thirds of all carotid patients, is eligible for CAS as an on-label treatment, he said. “The problem is that reimbursement, either through [the Centers for Medicare & Medicaid Services (CMS)] or private payers, is largely lacking, and that is a major inhibitor,” he commented.

The Next Hurdle: Reimbursement

In a press release, Abbott said that it intends to seek Medicare coverage. Whether CMS, which is often a bellwether for private insurance practice, will accede remains to be seen, Dr. Gray said, but the prospect seems reasonable.

“CMS is at the end of a long line of federal agencies involved with CREST and a long history of discussion about coverage of its enrollees,” he noted. “NIH sponsored the trial, FDA and other federal agencies oversaw it, and now FDA has given approval based on its results. The government has invested about $50 million [to establish] evidence-based medicine, which is how we say we want to make clinical decisions. It is hard for me to imagine that CMS would walk away from a government-sponsored trial that not only met its endpoints but that another government agency, the FDA, felt was successful.”  

Costs for carotid stenting and endarterectomy are roughly equivalent, Dr. Gray noted. “But the bigger question is whether [making CAS available] will increase the number of patients who are treated. That would obviously increase overall healthcare costs, but nobody knows the answer.”

The expanded indication is specifically for the Rx Acculink Carotid Stent System, which is used in conjunction with the RX Accunet embolic protection device. This means use of any other device in standard-risk patients would be off-label. “Abbott deserves recognition for doing the heavy lifting for over 10 years,” Dr. Gray noted. “That said, however, there’s no evidence of differences in outcomes between the various stents.”

The long effort to determine the proper role of CAS appears to be coming to fruition, “but it’s going to take a while,” Dr. Gray observed. “If [CMS coverage] comes to pass, then the next steps are to make sure that we have high-quality operators with sufficient experience performing CAS for the appropriate indications. There will always be some patients who will do better with stenting, and some who will do better with surgery. We want clinicians to use [these therapies] in a complementary way so that patients get the lowest risk procedure possible, regardless of what that is. That’s the way to reduce overall stroke rates and confer long-term benefit.”

Hopefully, the new indication will help make that possible, he added. 

2. FDA Expands Approved Use for Carotid Stent [press release] Accessed May 11, 2011.

Related Stories:

• CREST Published: Long-Term Outcomes Equivalent for Carotid Endarterectomy, Stenting
• Parsing the Panel: Reactions to Expanding CAS to Standard-Risk Patients
• Carotid Stenting Postmarket Studies May Not Reflect Real World