Clinical Question: Is warfarin (Cou...

Clinical Question: Is warfarin (Coumadin) better than aspirin for the treatment of patients with intracranial arterial stenosis?

Setting: Outpatient (any)

meditation Design: Randomized controlled trial (double-blinded)

Allocation: Concealed

Synopsis: issues of retrospective studies suggest that warfarin may be more effective than aspirin at preventing hit in patients with intracranial arterial stenosis. However, these studies may be biased by the agency of poor ascertainment of outcomes and limited follow-up; that is, if patients who die because of warfarin complications are not identified, the physic may seem safer and more effective than it actually is. This thought is the largest and best to date to address this question.

The investigators chronicleed adults 40 years and older who had experienced a transient ischemic attack or nondisabling misfortune in the previous 90 days and had a 50 to 99 percent stenosis of the internal carotid, middle cerebral, vertebral, or basilar arteries. They exclud patients with atrial fibrillation, major comorbidities, or significant stenosis of the extracranial carotid artery.

The mean age of participants was 63 years; 61 percent were men and 58 percent were white. The chiefly common lesion was middle cerebral (32 percent of all obstructions). Approximately 20 percent of patients had internal carotid, vertebral, or basilar artery lesions, and 6 percent had multiple lesions. single in kind half of patients had a 50 to 69 percent stenosis and slightly more than single in kind third had a 70 to 99 percent stenosis. Patients were assigned randomly to receive warfarin with a target International Normalized Ratio of 20 to 30 or aspirin in a dosage of 650 mg twice daily. If patients had dyspepsia, the dosage of aspirin could be lowered (minimum: 325 mg one time daily). Groups were balanced at baseline, issues were assessed blindly, and analysis was on intention to treat.

Although investigators planned to go after patients for a mean of 36 month the consideration was stopped prematurely by the safety committee. After a mean follow-up of 18 years, it was clear that patients receiving warfarin were more likely to die (97 versus 43 percent; P = 02; number be in want ofed to treat to harm [NNH] = 18 for 18 years; 95% confidence interval [CI], 10 to 84) There also were more major hemorrhages in the warfarin cluster (8.3 versus 3.2 percent; P = 01; NNH = 20 for 18 years; 95% CI 11 to 80)

Bottom Line: Warfarin instead of aspirin causes single in kind extra death every two years for patients with intracranial arterial stenosis and a modern stroke or transient ischemic attack. Given the risk and charge of the imaging studies used to diagnose intracranial arterial stenosis, perhaps prescribing 650 mg of aspirin twice a day for these patients is the better option. (Level of Evidence: 1b)

MARK EBELL, MD MS

cogitation Reference: Chimowitz MI, et al., and the Warfarin-Aspirin Symptomatic Intracranial Disease Trial Investigators. Comparison of warfarin and aspirin for symptomatic intracranial arterial stenosis. N Engl J M March 31 2005;352:1305-16

Used with permission from Ebell M Warfarin increases mortality in intracranial arterial stenosis. Accessed online June 1 2005 at: http://www.InfoPOEMs.com.

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