Novel antithrombotic agents for atrial fibrillation
Atrial fibrillation (AF) is the most common cardiac arrhythmia. It is estimated that 1 in 4 individuals aged 40 years or above will develop at least 1 episode of AF during their lifetime. Stroke is a leading cause of serious, long-term disability and death, and a major socioeconomic burden in developed countries. The major risk factor for thromboembolic stroke is AF. Oral antithrombotic treatment for AF patients has been limited to vitamin K antagonists for more than 60 years. Treatment with warfarin can reduce, but fails to abolish thromboembolic stroke associated with AF. Despite anticoagulation, patients with AF are at increased stroke risk. Furthermore, warfarin has important limitations namely, the limited time in therapeutic range, the need for INR monitoring, risk of major bleeding including stroke, and drug interactions. Recently there have been very exciting and important new advances in thromboprophylaxis for AF. Novel oral agents have been developed and evaluated clinically. These include direct thrombin inhibitors (dabigatran etexilate), oral selective factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and PAR-1 inhibitors (vorapaxar and atopaxar). Some of the new drugs have demonstrated promising results in the clinical studies, they are convenient in use and do not require monitoring. The downsides are lack of antidotes or specific blood assays to monitor the anticoagulant effect. This review evaluates traditional and novel approaches to thromboprophylaxis in patients with AF.