NASHVILLE, TENN. – In patients with symptomatic vertebrobasilar disease, low distal flow measured noninvasively predicted a patient’s subsequent risk for stroke in a multicenter, prospective study of 72 patients.
The finding “has implications for investigating interventional or aggressive medical treatments,” which should be aimed at this high-risk subgroup of patients, Dr. Sepideh Amin-Hanjani said at the International Stroke Conference, sponsored by the American Heart Association.
Mitchel L. Zoler/Frontline Medical News
Dr. Sepideh Amin-Hanjani
Patients with “the highest risk for recurrence have the best chance to benefit from intervention,” said Dr. Amin-Hanjani, professor of neurosurgery and codirector of neurovascular surgery at the University of Illinois at Chicago. For the time being, no interventions for vertebrobasilar disease have proven efficacy and safety, but the new finding provides a way to identify the highest risk patients who stand to gain the most from intervention and should serve as the target population for future trials.
The VERiTAS (Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke) trial enrolled 72 adults at any of five U.S. centers or at one in Canada. Enrolled patients had a recent stroke or transient ischemic attack in their vertebrobasilar territory plus angiographic evidence of at least 50% stenosis in an extra- or intracranial vertebral or basilar artery. All patients underwent quantitative MR angioplasty of their large vertebrobasilar arteries using software, Noninvasive Optimal Vessel Analysis (NOVA), that measures volumetric flow rates through vessels. Eighteen patients (25%) had low distal flow, defined as a greater than 20% reduction in flow, compared with normal, and 54 patients (75%) who had normal flow.
The study’s primary endpoint was an incident ischemic stroke in the vertebrobasilar territory during 12 months of follow-up. During a median follow-up of 23 months, 10 patients had this type of new stroke.
Among the 18 low-flow patients, four (22%) had a primary endpoint after 12 months, and among the 54 normal-flow patients, 2 (4%) had a primary endpoint after 12 months, a statistically significant difference, Dr. Amin-Hanjani reported at the conference.
In a multivariate analysis, low-flow at baseline linked with a significant, ninefold increased risk for incident stroke, compared with normal-flow patients. The location of the blockage – in the basilar region, vertebral region, or both – had no apparent impact on outcome.
About 30% of ischemic strokes occur in the posterior circulation, and about a third of those are caused by vertebrobasilar disease secondary to atherosclerosis. Overall patients who have had strokes of this type face a 10%-15% rate of new stroke annually despite receiving standard medical treatment, Dr. Amin-Hanjani said.
Dr. Amin-Hanjanihas received research grants from GE Healthcare and VasSol, the company that markets the NOVA software used in VERiTAS. A coauthor on the report has a significant ownership interest in VasSol.
On Twitter @mitchelzoler