Managing Stroke Risk in Atrial Fibrillation

Robert W. Griffith, MD

The main risk associated with atrial fibrillation is for a stroke, due to a clot forming in the heart, breaking off, and blocking a vessel in the brain. Consequently, patients are encouraged to take medication to prevent clot formation; this can be an anticoagulant or an antiplatelet drug. The Cochrane database has published a review of the protection offered by these two approaches, based on a meta-analysis of published studies.

Eight randomized trials, which included 9500 patients free from prior stroke or TIA, tested the anticoagulant warfarin (Coumadin®), given in doses adjusted according to clotting tests) against the antiplatelet drugs aspirin (in doses from 75 to 325 mg daily) or clopidogrel (Plavix®). The average duration of study was almost 2 years for each participant.

Patients on anticoagulants had a 33% reduction in the risk of stroke, and those on antiplatelet medication had a 20% reduction, compared with those on no preventive treatment. Moreover, myocardial infarctions were substantially (but not significantly) reduced by oral anticoagulants.

The findings show clearly that anticoagulants produce better results than antiplatelet therapy. However, many physicians select antiplatelet drugs because they don't require regular testing at an anticoagulant clinic. Without such testing, warfarin dosing becomes hit-or-miss - either ineffective (too little) or dangerous bleeding (too much). What is needed, of course, is an agent combining the effectiveness of warfarin with the safety of aspirin. That's still on the distant horizon, though.

Source
HealthandAge Blog

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