Warfarin-Aspirin Symptomatic Intracranial Disease Study "WASID"


Phase 3 Results

Trial Description

To compare the prophylactic efficacies of warfarin and aspirin against stroke and vascular death in patients with symptomatic stenosis of a major intracranial artery.


  • Aspirin (stroke prevention) Drug
    Intervention Desc: Antiplatelet agent; inhibits thromboxane A2
  • Warfarin (Coumadin┬«)Drug
    Intervention Desc: Anticoagulant (Vitamin K antagonist)

Trial Design

Prospective, double-blind, randomized, multi-center trial.

Patient Involvement

All participants must undergo conventional angiography to determine the degree af arterial stenosis. Eligible patients will be randomized to receive either aspirin 1300 mg/day or warfarin, titrated to an International Normalized Ratio (INR) of 2 - 3. All patients will receive monthly bloodtests, and will be evaluated by a neurologist every four months, until the end of the trial.


Type Measure Time Frame Safety Issue
Primary Incidence of ischemic stroke, hemorrhagic stroke, and vascular death.
Secondary Incidence of vascular death and disabling stroke, all stroke, all ischemic stroke, myocardial infarction, major systemic hemorrhage, intracranial hemorrhage, and ischemic stroke in the territory of the stenotic intracranial artery.


National Institute for Neurological Disorders and Stroke, NIH