Cath Lab Digest

Vascular Disease Management Speaks with CREST trial investigator, Christopher J. White, MD, FACC

What can you tell us about the latest findings from the CREST trial (Carotid Revascularization Endarterectomy vs. Stenting Trial) and the further evaluation of the data?

There is now more “texture” to the data, but the conclusion is still that there are no significant differences between the outcomes with carotid artery stenting (CAS) and carotid endarterectomy CEA). In essence, there were more minor strokes in the CAS group and more myocardial infarctions (MI) in the CEA group. Since there were three endpoints, they essentially evened out. The debates have tended to focus on the surgeons who perform CEA saying that strokes are worse than heart attacks and interventional cardiologists saying that MIs are worse than strokes. But this is nonsense — nobody wants a patient to have a stroke — big or small — and nobody wants a patient to have an MI. I do think that the differences are real and the CREST data are strong, and that this is an excellent study. These data allow us to better stratify patients for one procedure or the other based on their risk factors, such that those at risk for an MI should probably not undergo surgery, while those more at risk for stroke should probably undergo surgery as opposed to stenting.

There are certain anatomic features of carotid lesions that allow for more appropriate patient stratification. For example, heavily calcified or very tortuous carotid lesions render carotid stenting difficult. Those patients should clearly be sent for CEA instead of CAS. Patients with coronary artery disease — even those who are not very symptomatic — would likely fare better with a non-surgical approach to treat their carotid stenosis. So these risk-factor considerations allow practitioners to tailor the treatment to the appropriate patient as opposed to broadly recommending patients for one treatment strategy over the other. Of course, there will always be extremists who fall on one side of this debate or the other,

Do you anticipate changes in the CMS (Centers for Medicare and Medicaid Services) reimbursement policy as a result of these data? Specifically, do you expect a decision in favor of covering asymptomatic patients treated with carotid stenting?

A revised CMS guidelines document is expected very soon and has been endorsed by the surgical, cardiology and radiology societies. These guidelines are likely to be “stent neutral” in terms of allowing reimbursement for this treatment. I believe the guidelines will be in line with the CREST results, which direct practitioners to tailor the treatment to the particular patient’s risk profile. However, I do not think that CREST by itself will be enough to push the CMS to reimburse CAS procedures.

As for carotid stenting in asymptomatic patients, the risk for this subgroup was very low, at < 3% (2.5% for stenting; 1.4% for surgery). Thus, CREST was well below the 3% limit that the expert consensus panel recommended. As a result, I do not see why asymptomatic patients who are at risk for stroke would not be considered for either CEA or CAS. I am also comfortable with those who argue for medical therapy in these patients, but I see a steady stream of patients with 90% carotid stenoses referred to me by other physicians who say: “I don’t want my patient to have a major stroke, please fix this...”. There is no evidence from CREST that would discourage the CMS from reimbursing for carotid stenting procedures in these asymptomatic patients. The benefit of CAS for asymptomatic patients has been proven in randomized, controlled trials — though some are a bit dated (1990s), but that is not a reason for the CMS to decide that it is no longer appropriate to treat patients with asymptomatic carotid disease. I do think it would be reasonable to conduct another trial to compare this, but it would be arbitrary, capricious and overall harmful for the CMS to deny asymptomatic patients coverage for CAS.

Can you evaluate the relative weight of these findings:

- That patients > 70 years of age seemed to fare better with endarterectomy, and younger patients did slightly better with stenting?

It was shown to be true in CREST that patients > 70 years of age did slightly better with CEA, and those < 70 years of age did slightly better with CAS. CREST is not the only trial in which this was proven to be the case; the large European SPACE trial (Stent-Protected Angioplasty versus Carotid Endarterectomy) reached the same conclusions in this regard. There is no clear explanation for these results, but these data are real and consistent. My guess is that as people age, their lesions have more calcium and become more tortuous, thus rendering them less attractive candidates for carotid stenting. On the other hand, younger patients’ lesions are much softer, straighter and easier to navigate with a stent. And surgery outcomes seem to remain fairly consistent across the board.

- That there were more minor strokes in the carotid stenting group and more MIs in the endarterectomy group: