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February 2016

The High Risk of Low Distal Flow

Author Affiliations
  • 1Department of Neurology, Mayo Clinic Florida, Jacksonville
JAMA Neurol. 2016;73(2):157-158. doi:10.1001/jamaneurol.2015.3885

Symptomatic atherosclerosis of the vertebral artery remains a challenging condition with no proven interventional therapy. Completed randomized trials of angioplasty with or without stenting involving patients with symptomatic vertebral artery stenosis include Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS),1 Stenting vs Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS),2 and Vertebral Artery Stenting Trial (VAST).3 As the largest (N = 115) completed trial, VAST illustrates many of the challenges of developing interventional therapy for this patient population. During a median follow-up of 3 years, 12% of the patients in the stenting group and 7% of those in the medical group developed stroke in the symptomatic vertebral arterial territory. The VAST investigators estimated that, with this cumulative absolute rate of stroke events in the medical group, 9500 patients would have to be randomized in a future trial to provide compelling evidence of a 20% reduction in risk. With this in mind, it may be more productive—indeed, perhaps necessary—to reserve the development of interventional therapy for higher-risk populations. It may be useful for future trials to focus on providing treatment for patients sooner after their qualifying event. In VAST, only one-third of the medical group was enrolled within 14 days of their qualifying event.

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