Warfarin–Aspirin Recurrent Stroke Study - WARSS

Aug 08, 2006
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Date Published:
01/01/2001
Date Updated:
08/08/2006
Original Posted Date:
08/08/2006
References

Description:

The goal of the trial was to evaluate treatment with warfarin compared with aspirin for the prevention of recurrent ischemic stroke.

Study Design

Study Design:

Patients Enrolled: 2206
Mean Follow Up: 2 years
Mean Patient Age: Mean age 63 years
Female: 41

Patient Populations:

Age 30-85 years, acceptable candidates for warfarin therapy, ischemic stroke within the previous 30 days, and scores of ≥3 on the Glasgow Outcome Scale.

Exclusions:

Baseline INR >normal range (>1.4), stroke due to a procedure or attributed to high-grade carotid stenosis for which surgery was planned, or stroke associated with an inferred cardioembolic source.

Primary Endpoints:

Death from any cause or recurrent ischemic stroke at 2 years

Secondary Endpoints:

Death from any cause, recurrent ischemic stroke, or major hemorrhage at 2 years

Drug/Procedures Used:

Patients were randomized in a double-blind manner to either active aspirin (325 mg/day) plus placebo warfarin (n=1103) or active warfarin (2 mg/day initially, adjusted to maintain international normalized ratio (INR) of 1.4 to 2.8) plus placebo aspirin (n=1103).

Principal Findings:

Mean INR in the warfarin group was 2.1, with 70.7% of warfarin patients having an INR within the target range of 1.4 to 2.8, 13.0% above range, and 16.3% below range.

The primary endpoint of death or recurrent ischemic stroke at 2 years occurred in 17.8% of the warfarin group and 16.0% of the aspirin group (hazard ratio [HR] 1.13, p=0.25). There was no difference between groups in the rate of major hemorrhage (2.22 per 100 patient years in the warfarin group and 1.49 per 100 patient years in the aspirin group, p=0.10). However, minor hemorrhages occurred more frequently in the warfarin group compared with the aspirin group (20.8 per 100 patient years in the warfarin group and 12.9 per 100 patient years in the aspirin group, p<0.001). There was no difference in the composite of death, recurrent ischemic stroke or major hemorrhage (20.0% for warfarin vs 17.8% for aspirin, p=0.16).

Interpretation:

Among patients with prior ischemic stroke, treatment with warfarin was not associated with a difference in death or recurrent ischemic stroke at 2 year follow-up compared with treatment with aspirin.

The lack of benefit with warfarin was observed despite obtaining INR target ranges in the majority of patients. Other studies have demonstrated a reduction with warfarin in recurrent stroke associated wtih atrial fibrillation, but these findings did not extend to the population studied in the present trial.

References:

Mohr JP, Thompson JL, Lazar RM, et al., on Behalf of the Warfarin-Aspirin Recurrent Stroke Study Group. A comparison of warfarin and aspirin for the prevention of recurrent ischemic stroke. N Engl J Med 2001;345:1444-51.

Keywords: International Normalized Ratio, Stroke, Follow-Up Studies, Platelet Aggregation Inhibitors, Warfarin, Glasgow Outcome Scale, Hemorrhage


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