Evidence points to aggressive medical management as the standard of care for stroke prevention in patients with intracranial arterial stenosis, and research suggests the same holds true for stenosis of the carotid artery. But the road to evidence-based standards is lined with complications.
Intracranial arterial stenosis and carotid arterial stenosis (CAS) serve as examples of opposite methods in best-practice prevention determination. Where determinations for the first have been defined through multiple studies built on one another, the second suffers from a lack of testing with modern medical advances. As a result, the safety and efficacy of stenting versus medical management is relatively conclusive for intracranial stenosis but not for carotid arterial stenosis.
Marc I. Chimowitz, M.B., Ch.B., is a professor of neurology and Dean of Faculty Development at the Medical University of South Carolina, where he led a 2011 study on the occurrences of stroke after aggressive medical therapy versus after stenting for patients with intracranial arterial stenosis. This study, published in The New England Journal of Medicine, found stroke risk was lower for patients with aggressive medical management than for patients undergoing percutaneous transluminal angioplasty and stenting, and the difference in occurrences between the two methods was greater than previously observed.
“While more research needs to be done to lower the rates even further, this study and others before it show aggressive medical management should become the standard of care for intracranial stenosis,” Dr. Chimowitz says. “Unfortunately, in the carotid field, it’s harder for researchers to run clinical trials comparing the two types of prevention, especially since Medicare already reimburses, in some capacity, for stenting in the neck.”
Dr. Chimowitz observes that Medicare is not supporting a problematic procedure; rather, some practitioners believe the evidence for one type of stroke prevention for carotid arterial stenosis patients has yet to be definitively studied. In an article published in the March 2012 issue of the journal Brain and Behavior, 41 leading academic stroke-prevention clinicians detailed the current evidence for best-practice-based prevention efforts. They concluded, most specifically, that Medicare should not broaden reimbursement for carotid artery stenting for stroke prevention until more research can be done.
“Extending the approved indications for [carotid angioplasty/stenting] will open the floodgates for widespread [carotid angioplasty/stenting],” the group writes. “[It will] expose patients to unnecessary risk and greatly increase unjustified health expenditure.”
Outdated research further muddies the discussion. Studies looking for evidence of the type the 41 clinicians request have been performed, but they date back to the 1990s, a time when drug therapies were less advanced. As a result, the efficacy and safety of stenting was validated over aggressive medical management.
With these complications, researchers and clinicians focused on CAS may need to blaze a new path to catch up with their colleagues in the intracranial arm of stroke prevention and achieve legitimate evidence-based best practices.