Key points are not available for this paper at this time.
The popularity of warfarin, a drug that has been in clinical use for approximately 50 years, has waxed and waned and is currently on the rise. The recent interest in clinical use has been stimulated by the observation that less intense warfarin regimens are as effective as, but produce much less bleeding than, the high-intensity regimens that were standard in North America in the past. Thus, results of randomized trials have demonstrated that low-intensity regimens are as effective as, but much safer than, high-intensity regimens for the treatment of venous thrombosis and for the prevention of systemic embolism in patients with tissue heart valves and, more recently, in patients with mechanical heart valves1-3(Table). These findings provided the impetus for clinical trials assessing the relative risks and benefits of low-intensity warfarin in patients with nonvalvular atrial fibrillation.4,5The results have been impressive—a greater than 60% risk reduction in
Jack Hirsh (1991) studied this question.