Statistics show that one-third of all strokes are caused by atrial fibrillation. Anticoagulation is therefore particularly important in prophylaxis for these patients. Although warfarin, which has long been used as a vitamin K antagonist, still belongs in the armamentarium, current studies show that the novel oral anticoagulants (NOAC) are partially superior to vitamin K antagonists.
For decades warfarin as a vitamin K antagonist was the remedy in anticoagulation therapy - and yet today it must increasingly be regarded as the anticoagulant of the past century. Although it is still widely used, the drug has some limitations, such as the slower onset of action, poorer controllability, or prolonged after-effects when discontinued.
Warfarin has been shown in studies to be good stroke prophylaxis for patients with atrial fibrillation. Such prophylaxis, then as now, is primarily a search for the balance between anticoagulation and the risk of bleeding.
With dabigatran (antithrombin) and the novel oral anticoagulants (NOAC), such as rivaroxaban, apixaban, and edoxaban (factor X antagonists), there is currently a further development not only in the field of stroke prophylaxis.
Although it should be noted that the results on the effect of NOAC are strongly influenced by the study, in particular by patient selection, it is clear that NOAC is at least equivalent in efficacy to warfarin. In addition, NOACs are usually even safer than vitamin K antagonists in relation to severe bleeding events and reliably reduce the risk of stroke.
Based on the current study situation, NOAC can probably be described as an anticoagulant of the 21st century, at least for the next 25 years. Leading guidelines on atrial fibrillation and stroke prophylaxis now also clearly see NOAC in the first line of treatment options for this patient group and recommend them before vitamin K antagonists.
However, direct comparisons of effects and side effects of individual NOACs are currently not possible, as there are no randomized controlled trials (RCTs) or real-world data that have directly compared NOAC with each other. For the time being, all that remains is to select the best possible drug for stroke prophylaxis for a particular patient based on efficacy and bleeding risk. NOAC is recommended in addition to stroke prophylaxis, e.g. after knee arthroplasty and Deep vein thrombosis (DVT) + pulmonary embolism (PE).
In addition, further studies are currently underway to test combination therapies for certain indications. The combination of ASA and rivaroxaban was already more effective than the respective monotherapy.
The use of dabigatran also has some advantages over warfarin. In emergency situations or when operations are pending, anticoagulation with dabigatran can be stopped almost immediately. This is possible thanks to the antidote idarucizumab.
Plenary Lecture "Anticoagulation in the 21st century" (H. Darius), GTH19; Berlin, 28.02.2019