Management of Carotid Stenosis in 2012: How Much Do We Really Know?

This past January, the Centers for Medicare & Medicaid Services (CMS) convened a meeting of the Medicare Evidence Development & Coverage Advisory Committee (MEDCAC) to review available evidence on the various clinical strategies for the treatment of carotid artery stenosis.The primary focus for this MEDCAC meeting was whether or not carotid artery stenting (CAS), carotid endarterectomy (CEA), and/or best medical therapy (BMT) improve clinical outcomes in symptomatic and asymptomatic patients with carotid atherosclerotic disease.CMS was most interested in stroke prevention, and the health outcomes of interest are all-stroke and all-cause mortality. The panel’s input was also sought on whether the published evidence for these strategies could be generalized to the Medicare population. Clifford Goodman, PhD, of The Lewin Group (Falls Church, VA), a health care consulting firm, served as Chair of the MEDCAC panel, with CMS’s Steve E. Phurrough, MD, serving as Vice Chair. The panel was composed of 9 voting members and 4 nonvoting members. The panel heard presentations by invited guest speakers, including Thomas G. Brott, MD, who serves as Principal Investigator of the CREST trial, and William A. Gray, MD. Leaders of the Society of Interventional Radiology, Society for Vascular Medicine, Society of NeuroInterventional Surgery, Society for Vascular Surgery, American College of Cardiology, American Association of Neurological Surgeons, and Society for Cardiac Angiography and Intervention also provided public commentary.

The 9 voting panelists considered and voted on their confidence in the available evidence to properly address coverage of treatment. The confidence level was measured on a scale of 1 (low or no confidence) to 5 (high confidence). The following treatments were considered and assigned a confidence level:

• The average panel score was 3, or intermediate confidence, on whether there is adequate evidence to determine if patients in the Medicare population who are asymptomatic for carotid atherosclerosis can be identified as high risk for stroke in either cerebral hemisphere.
• The average score was 3.56 on whether there is adequate evidence to determine if patients in the Medicare population, who are considering carotid revascularization, can be identified as being at high risk for adverse events from CEA.
• The panelists voted that they had intermediate confidence (3.33) about adequate evidence to determine whether or not CAS or CEA is the favored treatment strategy, as compared to BMT alone, to decrease stroke or death in the Medicare population for those patients with symptomatic carotid atherosclerosis and carotid narrowing who are not generally considered to be at high risk for adverse events from CEA. The panelists were also asked to measure their confidence in each option as the favored treatment for this population. They voted with a level of confidence of 3.44 for CEA, 2 for CAS, and 1.56 for BMT alone, indicating that the evidence most strongly favored surgical endarterectomy as the preferred treatment in this population.
• For those patients with asymptomatic carotid atherosclerosis and carotid narrowing who are not generally considered to be at high risk for adverse events from CEA, the panelists voted an average level of 2 that there is adequate evidence to determine whether or not either CAS or CEA is the favored treatment strategy, as compared to BMT alone, to decrease stroke or death in the Medicare population.
• For those patients with asymptomatic carotid atherosclerosis who are not considered to be at high risk for stroke in either cerebral hemisphere, the panel voted on average with intermediate confidence (2.89) that there is adequate evidence to determine whether or not CAS, CEA, or BMT alone is the favored treatment strategy to decrease stroke or death in the Medicare population. The panelists expressed their highest average level of confidence (4.22) for BMT alone as the favored treatment in this population and voted low confidence (1) for both CAS and CEA.
• The panel had a 3.33 confidence level that there is adequate evidence to determine whether or not carotid artery screening of asymptomatic patients in the general Medicare population decreases stroke or death but only a 1.33 average level of confidence that carotid artery screening of asymptomatic patients decreases stroke or death.