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Warfarin Versus Aspirin Recurrent Stroke Study

This study has been completed.
National Institute of Neurological Disorders and Stroke (NINDS)
Information provided by:
Columbia University Identifier:
First received: November 20, 2001
Last updated: June 16, 2011
Last verified: June 2011
The goal of this study is to compare aspirin to warfarin for the prevention of recurrent stroke.

Condition Intervention Phase
Stroke Drug: Active Aspirin Drug: Active Warfarin Drug: Aspirin placebo Drug: Warfarin placebo Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Prevention
Official Title: A Comparison of Warfarin and Aspirin for the Prevention of Recurrent Ischemic Stroke

Resource links provided by NLM:

Further study details as provided by Columbia University:

Estimated Enrollment: 2206
Study Start Date: June 1993
Study Completion Date: November 2001
Primary Completion Date: June 2000 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Active Warfarin and Aspirin Placebo
One 2 mg scored tablet daily of Warfarin and one 325 mg tablet daily of aspirin placebo.
Drug: Active Warfarin
2mg scored tablet daily
Drug: Aspirin placebo
325mg aspirin placebo pill
Active Comparator: Active Aspirin and Warfarin Placebo
One 325 mg tablet daily of aspirin and one 2 mg scored tablet daily of Warfarin placebo.
Drug: Active Aspirin
325mg tablet daily
Drug: Warfarin placebo
2mg scored placebo tablet

Detailed Description:

This study compared aspirin to warfarin to determine optimal therapy for the prevention of recurrent stroke. Both drugs slow clotting of the blood. Blood clots are involved in the final stages of the most common type of stroke due to blockage of the vessels that supply oxygen-rich blood to the brain. Aspirin affects the blood platelets, while warfarin inhibits circulating clotting proteins in the blood. Numerous previous studies have proven that use of aspirin reduces recurrent stroke by about 25 percent. Part of the controversy about aspirin versus warfarin for stroke prevention has been the thinking among clinicians that warfarin may be a better blood thinner than aspirin to prevent almost all forms of stroke, but that it has greater side effects, increased risk of hemorrhage, and higher costs due to the need for blood tests to monitor the treatment effect for patients.

To make the aspirin and warfarin arms of the study as unbiased as possible, the investigators matched both groups of patients for primary stroke severity, age, gender, education, and race/ethnicity. The two groups were also matched for stroke risk factors, including hypertension, diabetes, cardiac disease, smoking, alcohol consumption, and physical activity. The investigators used an aspirin dose of 325 mg/day and a warfarin dose specifically tailored to each individual patient.

This study found that aspirin works as well as warfarin in helping to prevent recurrent strokes in most patients.


Ages Eligible for Study:   30 Years to 85 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No


  • Acceptable candidates for warfarin therapy
  • Had an ischemic stroke within the previous 30 days
  • Had scores of 3 or more on the Glasgow Outcome Scale


  • Base-line INR above the normal range (more than 1.4)
  • History of stroke due to a procedure or that was attributed to high-grade carotid stenosis for which surgery was planned
  • History of stroke associated with an inferred cardioembolic source
  Contacts and Locations
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Please refer to this study by its identifier: NCT00027066

United States, New York
Columbia University Health Sciences
New York, New York, United States, 10032
Sponsors and Collaborators
Columbia University
National Institute of Neurological Disorders and Stroke (NINDS)
Principal Investigator: J. P. Mohr, M.D. Columbia University Health Sciences
  More Information

Additional Information:
Responsible Party: Jay Preston Mohr, MD, Columbia University Identifier: NCT00027066     History of Changes
Other Study ID Numbers: R01NS028371 ( U.S. NIH Grant/Contract )
Study First Received: November 20, 2001
Last Updated: June 16, 2011

Keywords provided by Columbia University:

Additional relevant MeSH terms:
Cerebrovascular Disorders
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Vascular Diseases
Cardiovascular Diseases
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action
Platelet Aggregation Inhibitors
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Anticoagulants processed this record on September 21, 2017