Cath Lab Digest

Interview with Co-Principal Investigators of the ARMOUR Trial: Gary Ansel, MD and L. Nelson Hopkins, MD

What was the purpose and scope of the ARMOUR trial? What were the trial’s
primary and secondary end points?
ANSEL: The purpose of the trial was to test a proximal protection device for carotid artery stenting (CAS) called the Mo.Ma^® Ultra Proximal Cerebral Protection Device (Invatec, Inc., Bethlehem, Pennsylvania). This is a flow-clamping device to allow for CAS. The primary endpoints were MACE, which included any myocardial infarction, stroke or death.

What was the patient population studied?
HOPKINS: We studied the patients at high surgical risk for carotid endarterectomy (CEA): 225 subjects were in the intention-to-treat registry and 37 were roll-in patients, for a total of 262 patients.

What kind of inclusion criteria were used?
HOPKINS: Patients considered to be at high risk for CEA surgery either based on either anatomical or physiological measures. For example, any patient who had a carotid artery stenosis that was out of reach for an endarterectomy procedure, or was in a surgically hostile neck — such as in patients with recurring restenosis who had significant scarring from previous surgery; patients who had major previous neck surgery or immobility of the neck; patients with occlusions in the other carotid artery who therefore do not have very good collateral circulation. There were also physiological parameters that guided patient selection: patients with multivessel coronary artery disease, unstable angina, heart failure, ejection fraction <30%, and those with severe pulmonary disease who cannot risk undergoing general anesthesia.

Overall, what do you think the results of this trial will mean for treatment of carotid artery disease in the U.S.?
HOPKINS: I think the potential impact is huge. Needless to say, nobody is happy about the fact that the CMS (U.S. Centers for Medicare and Medicaid Services) came out on December 9th with a continued non-coverage decision for about 90% of patients with carotid stenosis who would be potential candidates for CAS. Patients who were symptomatic within the previous 2 weeks have been shown to be at increased risk for CAS, yet those patients are at greatest risk for stroke from the natural history of the disease. We would like to be able to treat these patients, but the risk of stenting appears to be greater in this subset. The exciting thing about the ARMOUR study is that it shows a 0% risk for recently symptomatic patients and a very low risk (2%) in another high-risk subset: patients >80 years of age. The results of this trial show that CAS is a potential solution for patients who were previously thought to be at high risk for CAS. Equally exciting is the technology involved, which allows us to treat patients with carotid artery stenosis in much the same way surgeons do, in that flow is completely stopped, the procedure is performed, and then any debris is removed by aspirating the debris-laden blood. This is very similar to what is done in surgery, which has been shown to be quite safe overall in selected patients. The Mo.Ma device allows the operator to produce the environment that is created in surgery. I think this is a potentially very exciting advance in the treatment of patients with carotid stenosis.

ANSEL: I think the CMS’s decision not to cover CAS procedures may be evidence that the government is more financially-driven than patient-care driven. We physicians know that there are patients who are best treated by CEA and those who are better treated by stenting. The government seems to consider these as competing technologies and is just worried about the cost, whereas physicians are more focused on patient outcomes. The Mo.Ma device is another piece of equipment with success rates to offer patients who may be best treated with a stent versus endarterectomy. To see a 0% stroke rate in the symptomatic patients and a very low stroke rate in all patients across the board shows that the field is maturing, and hopefully we can mature as a country as well and arrive at providing what’s best for patient care, especially as the universal health-care debate carries on.