Carotid Stenting: Where Science & Policy Diverge

A 68-year-old gentleman was recently referred to me by his cardiologist, who had heard a carotid bruit on a routine exam. The patient told me that he did not want to have carotid surgery because his older brother, who had undergone surgery, suffered vocal cord paralysis and still could not speak correctly. A carotid duplex study demonstrated a critical stenosis greater than 80 percent, and angiography confirmed the severity of the lesion and favorable anatomy for stent placement.

After reviewing the patient’s data, I informed him he was a candidate for a carotid stent but that Medicare would not pay for his procedure. Medicare would pay for him to have surgery, but unless he was willing to pay up to $20,000 out of pocket, he could not have a stent. My patient was surprised. His cardiologist had reassured him that he would be able to avoid surgery. He asked me why Medicare would not allow him to have choice of revascularization procedures if he and his doctor thought carotid stenting was a reasonable treatment option.

My patient did not qualify for Centers for Medicare & Medicaid Services (CMS)-approved carotid stent therapy because the only pathway open to him was participation in a clinical trial and ACT-1, the last remaining clinical trial for asymptomatic patients, had closed the week before. The company sponsoring ACT-1 already has an FDA-approved carotid stent system but at this point it has little hope that CMS will ever cover asymptomatic patients at risk for stroke with carotid artery stenting, even though carotid stenting has been shown to be equally safe and effective as surgery and is much less invasive than surgery.

When ACT-1 closed, average surgical-risk asymptomatic patients with carotid artery disease, including mine, lost their last hope of avoiding surgery despite the results of CREST (N Engl J Med 2010;363[1]:11-23), the largest ever randomized carotid stent trial, completed three years ago. CREST found no difference between carotid stenting and carotid endarterectomy after four years of follow-up. CMS has refused every request to cover stents for these patients, despite the opinions of multiple professional specialty societies, including cardiologists, surgeons, radiologists and neurologists, who in 2011 endorsed the choice of stents vs. surgery as a reasonable option for average surgery-risk patients (Stroke 2011;42[1]:227-76; Stroke 2011;42:e420-463). And now, with the closure of ACT-1, physicians have lost our only means to offer a choice of carotid stent therapy to asymptomatic patients despite FDA approval of seven different carotid stent systems found to be “safe and effective.” There are no exceptions, even for patients for whom stenting would clearly be the best option.

Why will CMS cover carotid surgery in low-risk asymptomatic patients but not cover carotid stenting in those same patients, even though the data demonstrate “equipoise”? Although I have been actively involved in efforts to persuade CMS and have personally spoken with CMS officials countless times, I must admit I still don’t know why my patients are being denied the choice of less invasive therapy, stenting rather than surgery, to prevent a stroke.

On the crest of a clinical option

The Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST) was designed to compare carotid-artery stenting with carotid endarterectomy in patients with symptomatic or asymptomatic extracranial carotid stenosis (N Engl J Med 2010;363[1]:11-23). The randomized, controlled clinical trial enrolled 2,502 patients with symptomatic or asymptomatic carotid stenosis to undergo carotid-artery stenting or carotid endarterectomy. The composite endpoint was stroke, MI or death from any cause during the periprocedural period or any ipsilateral stroke within four years after randomization.

Key findings included:

  • No difference between the groups in the primary endpoint based on symptomatic status or sex;
  • At four years, the rate of stroke or death was 6.4 percent in the carotid-artery stenting group vs. 4.7 percent in the endarterectomy group;
  • In symptomatic patients, the rates were 8 percent vs. 6.4 percent;
  • In asymptomatic patients, the rates were 4.5 percent vs. 2.7 percent;
  • The periprocedural risk was higher in the stenting group for stroke (4.1 percent vs. 2.3 percent) but lower for MI (1.1 percent vs. 2.3 percent); and
  • Ipsilateral stroke rates were 2 percent vs. 2.4 percent.
  • "The differential results for myocardial infarction and stroke offer opportunities for improvement," the authors wrote. "To reduce the risk of stroke after carotid-artery stenting, improvements in training and technique, embolic protection and stent design and patient selection (especially among patients older than 70 years of age) hold promise."

History lesson

This story really began in the mid-1980s, when CMS issued a national non-coverage decision (NCD) for angioplasty of obstructive lesions of the carotid, vertebral and cerebral arteries, which specifically prevented coverage in Medicare beneficiaries (Health Aff 2001;20[5]:83-85). In 2001, 2004 and 2005 the NCD was expanded to allow coverage for carotid stenting as part of FDA-approved clinical trials and for high-risk symptomatic patients with 70 to 99 percent carotid artery stenosis. In 2008 and again in 2009, following publication of favorable studies including 8,000 carotid stent patients, CMS declined to expand coverage and gave no reason for its decision. Many believe CMS’s “inaction” has been driven by physician and surgeon “turf battles,” which have allowed CMS to ignore the science supporting the much-desired less invasive therapy.  

As a doctor committed to optimal patient care, I find this situation intolerable. As a scientist, I find it unacceptable. There really are no more trials to perform; the data are in and they show no overall difference in outcomes for carotid stenting and carotid surgery for stroke prevention when experienced operators and high-volume institutions are involved. Furthermore, by acting in an unpredictable and nontransparent manner, CMS is killing the innovation needed to continue developing less invasive methods to prevent stroke. Companies have few choices other than to leave the field and close their trials because they cannot afford to work with such an unreliable, unpredictable, and silent partner as CMS.

The fact is, no one I have talked to knows what it will take to get CMS to cover carotid stenting for patients like mine, and CMS is not talking. This is unacceptable behavior for an organization that runs on taxpayer funding and whose responsibility is to patients. CMS must hold itself above the fray, ignore selfish and self-serving turf battles and make decisions in patients’ best interest. CMS officials must, like the FDA, base their decisions on the clinical evidence.

If CMS does this, patients and their doctors will be able to consider the evidence as it applies to individual patients and make patient-centered decisions. For any single patient, the right choice might be medical therapy or surgery, or it might be stenting. Whatever the case-by-case decision, the scientific evidence does not support the arbitrary continuation of a 25-year-old, government-imposed ban that prevents seniors, with the advice of their physicians, from choosing which treatment is best for them. What the evidence does support is patients and doctors having a choice.

Dr. White is immediate past president of the Society for Cardiovascular Angiography and Interventions.