Warfarin Versus Aspirin Recurrent Stroke Study

This study has been completed.
National Institute of Neurological Disorders and Stroke (NINDS)
Information provided by:
Columbia University
ClinicalTrials.gov 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
Drug: Active Aspirin
Drug: Active Warfarin
Drug: Aspirin placebo
Drug: Warfarin placebo
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, 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
Genders Eligible for Study:   Both
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
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Please refer to this study by its ClinicalTrials.gov 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
ClinicalTrials.gov Identifier: NCT00027066     History of Changes
Other Study ID Numbers: R01NS028371 
Study First Received: November 20, 2001
Last Updated: June 16, 2011
Health Authority: United States: Institutional Review Board

Keywords provided by Columbia University:

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

ClinicalTrials.gov processed this record on May 30, 2016