Photo reproduced with permission (Orbach et al., 2006).
Data from the CREST trial can help identify which patients should be treated with carotid stents, shown here in a virtual angioscopic view.
"The most important factors" guiding the decision of whether or not to perform CAS are, does a symptomatic patient has "hot" lesions, what is the arterial tortuosity, and what is the calcification, he said. Other important features include whether the patient has a contralateral carotid occlusion, whether the carotid has a high bifurcation, and whether there are ostial or tandem lesions. "If the anatomy is favorable, CAS is fine even in a 95-year-old," Dr. Hopkins said.
What About Insurance Coverage?
Carotid specialists concede that another, nonmedical issue also plays a big role in deciding how to manage a patient: What will the patient’s health insurance cover?
In its most recent decision on the issue, effective in April 2010, the Centers for Medicare and Medicaid Services (CMS) said that Medicare covers CAS performed on a routine basis for patients with symptomatic carotid disease who are at high risk for CEA and have at least 70% carotid stenosis. CMS also said that Medicare will cover FDA-approved investigations of CAS in symptomatic patients who are at high risk for CEA and have at least 50% stenosis, as well as CAS investigations in asymptomatic patients at high risk for CEA with at least 80% carotid stenosis.
As a result, patients with other forms of carotid disease often do not have insurance coverage for CAS.
"The issue for us is primarily reimbursement. If we can do [a procedure] and be reimbursed, we often stent the patient," said Dr. Carlos H. Timaran, a vascular surgeon and chief of endovascular surgery at the University of Texas Southwestern Medical Center in Dallas.
"For my private practice patients, we assess their risk based on their [anatomical] and medical criteria. If they are high risk, we usually stent. We have a bias toward stenting because it is faster and easier. Some people say they can do endarterectomy in an hour, but I don’t believe that. I do CEA with residents and fellows, and it takes 2 hours. But with stenting, I can do it in 40 minutes, even with a fellow. If I have three patients with carotid disease to treat [and] if I do CEA on all three, it will take all day. If I do CAS, it will take the morning, or less," he said in an interview.
In addition, "CEA is a nice procedure, but you need anesthesia. CAS is easier, I can do it myself, and I don’t need anesthesia. I am in more control of the case," Dr. Timaran said.
For patients who are eligible for both CAS and CEA, "it also comes down to anatomy," he grants. But if the patient has anatomy favorable to either method, "I offer patients both, and they will probably go for a stent," because patients usually prefer the quicker recovery that stenting offers, compared with CEA.
Dr. Thomas G. Brott
An interesting footnote to the issue of how to best manage patients who are eligible for CAS under CMS rules is that the CREST results offer no direct guidance on the relative safety and efficacy of CAS and CEA in patients with Medicare coverage. That’s because "the CREST cohort was a conventional-risk cohort; most criteria that would make someone a high surgical risk would have been excluded from CREST," Dr. Thomas G. Brott, professor of neurology at the Mayo Clinic in Jacksonville, Fla., and lead investigator for CREST. "The high-surgical-risk patients who are currently covered by Medicare would not have even been enrolled in CREST," Dr. Brott said in an interview.
Where Does Medical Therapy Fit In?
Although Dr. Timaran sees the potential value of medical therapy only for asymptomatic patients, he also urges caution.
"I don’t think [the efficacy of medical treatment] has been proven, and until it’s proven I don’t think physicians should deny revascularization treatment to these patients," he said. "The standard of care for a patient with severe carotid stenosis is revascularization, even if the patient is asymptomatic, unless there is some other consideration." But, he admitted, "there is little downside to medical treatment in asymptomatic patients, even if they have severe stenosis." That’s because their stroke risk is low regardless of which option a patient chooses.
"I tell asymptomatic patients that ‘based on the data, your risk of stroke is 2% per year, and that risk may be even lower with best medical therapy.’ With a carotid intervention, we can lower their risk to 1% per year." In other words, the patient’s stroke risk is low regardless of which option is chosen. Plus, medical therapy only is the best choice for patients with special risk factors, such as radiation-induced stenosis, Dr. Timaran added.