Bleeding complications are perhap s the biggest concern for indicated patients. New studies in Europe and phase 2 of the Stroke Prevention in Atrial Fibrillation study comparing warfarin with asa suggest patients 75 years and over should use warfarin (low intensity) and asa to reduce stroke risk and major bleeding complications. Also, low risk stroke patients (2%/ year) bet ween 60 and 75 years old appear to be adequately protected against stroke with asa therapy. These findings need to be confirmed with prospective trials such as phase 3 of the Stroke Prevention in Atrial Fibrillation study, cur rently in progress.
It is important to keep in m ind, however, that fatality due to bleeding complications (for the warfarin group) are 8.4 times lower than fatality due to an embolic event (for the warfarin group), further supporting the protective effect of warfarin therapy. Furthermore, the risk of a fatal stroke is reduced by 15% for the warfarin group compared with the placebo group, alihough both are infrequent (1.94% ver sus 2.27%, re ipec-tively).
In an effort to address the risks associated with warfarin treatment, such as increased bleeding complications, comparisons have been made with other treatments. Cardioversion followed by antiarrhythmic cheap drugs have been suggested as an alternative to warfarin. In one study, cardioversion followed by amiodarone treatment resulted in quality-adjusted life-years of 4.75, with warfarin a close second with a value of 4.72. Quinidine and no treatment resulted in quality-adjusted life-years of 4.68 and 4.55, respectively, in the same study. The benefits of these strategies (amiodarone, warfarin and quinidine), compared with no treatment, results in 10.4, 8.8 and 6.8 weeks of increased quality of life respectively. These kinds of data provide meaningful information about alternatives to warfarin treatment and underscore the relative efficacy of warfarin. Although the warfarin alternatives have a greater reduction for the risk of stroke (except no treatment), quinidine and amiodarone patients have 42% and 36% risks, respectively, of reverting to atrial fibriliation within six months, at which point warfarin may be used.