CMS: More data needed on best management of blocked carotid arteries

After covered stent deployment, lateral view, demonstrating Jostent covered stent in cavernous segment of internal carotid artery along guidewire. Source: Korean J Radiol 2010;11(6):603–611.

The Centers for Medicare & Medicaid Services (CMS) held a meeting Jan. 25 with the hope of strengthening carotid atherosclerosis management. During said meeting, the Medicare Evidence Development & Coverage Advisory Committee (MEDCAC) voted on evidence, procedures and the most beneficial strategies for the management of atherosclerosis to prevent stroke, with most members agreeing that more data are necessary.

Currently, CMS covers coronary artery stenting for patients at a high risk of adverse events from carotid endarterectomy (CEA) for:

• Symptomatic patients with a stenosis greater than or equal to 70 percent;
• Symptomatic patients with a 50 to 70 percent stenosis when procedures are performed in FDA approved category B Investigational Device Exemption (IDE) trials or FDA approved post approval studies; and
• In asymptomatic patients with greater than 80 percent stenosis when procedures are performed in FDA approved trials.

Members looked at both symptomatic and asymptomatic patient populations to discuss whether carotid artery stenting (CAS), CEA and optimal medical therapy (OMT) improved outcomes in atherosclerotic patients. Additionally, CMS looked to understand whether previously published data on the topic are generalizable to the Medicare population.

Members voted on six questions and used the following responses: low confidence, intermediate confidence or high confidence. Questions dealt with whether CAS or CEA is the favored treatment strategy in certain patient populations, previous data outlining the benefits/risks of CAS or CEA as opposed to OMT and what should be done in the future, among others.

During the meeting, William A. Gray, MD, associate professor of Medicine at the Columbia University Medical Center in New York City, said the “concept of a ‘low-risk’ patient has not clearly been defined, nor identified.” Additionally, Gray said that to date, there are no trials that assess patients who are at a high surgical risk, and that post-trial CEA outcomes cannot be generalizable to those who were not enrolled in the trial.

Gray said that in symptomatic patients, CEA and CAS “appears equivalent” in terms of outcomes and stroke in the CREST trial, but noted women did better with CAS compared with CEA in the EVA-3S and ICSS trials.

Lastly, Gray said that the “correct cocktail of medical class” is missing in asymptomatic patients to determine the most optimal medical therapy to treat those with carotid artery disease. “The role of medical therapy remains a tantalizing but unproven alternative to revascularization in patients with established severe carotid stenosis,” Gray said in a statement.

Meanwhile, Robert M. Zwolak, MD, PhD, of the Dartmouth-Hitchcock Medical Center in Lebanon, N.H., looked at the real-world results of CAS and CEA during a presentation at the meeting, and concluded that real-world results are not always comparable to what is found in randomized controlled trials.

Zwolak used 30-day stroke and death rates post-CAS and CEA from the SVS Registry as an example. Of 1,450 CAS patients and 1,368 CEA patients, the combined rates of stroke, death and MI were nearly 6 percent for CAS patients compared with nearly 3 percent in CEA patients. The 30-day stroke rates for CAS and CEA for asymptomatic patients were 2.11 percent vs. 1.28 percent, and 5.27 percent vs. 2.37 percent in symptomatic patients. Based on a Nationwide Inpatient Sample analysis, Zwolak reported that stroke and death rates in high surgical risk patients to be nearly two times higher after CAS vs. CEA.

“Even after risk-factor adjustment, stroke risk is likely greater after CAS in population-based studies,” Zwolak said.

When asked to vote on whether there is accurate evidence to determine whether or not CEA or CAS is the favored treatment as compared to optimal medical therapy in the Medicare population, the majority of the voting body said they had low- to intermediate- confidence about the data. This question was asked about asymptomatic patients not considered high risk for adverse events with CEA.

All voting members said that they had low confidence that CAS would be the favored treatment strategy in asymptomatic carotid atherosclerosis patients who were not at high risk for stroke. However, many said they had high confidence that optimal medical therapy alone should be the favored treatment strategy in this patient population.

All in all, the majority of the panelists agreed that more data are necessary to better define the best treatment strategy—CEA, CAS or OMT—for atherosclerotic Medicare patients.