Risk Stratification For and Use of DOAC Therapies for Stroke Prevention in Patient with Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia, complicated by a fivefold increased risk of ischemic stroke due to thromboembolism. Anticoagulant agents play a key role in preventing this complication. Through years, several risk stratification algorithms have been investigated, while others are still object of debate. According to current guidelines, CHA2DS2VASc score and HAS-BLED score are the ones suggested for stroke and bleeding risk stratification, respectively. The improvement of knowledge and, eventually, the validation of novel risk score systems may lead to a better risk stratification and tailored therapy. Up to now, direct oral anticoagulants (DOACs) are recommended over warfarin for stroke prevention in high risk patients with non-valvular atrial fibrillation. In fact, DOACs demonstrated an efficacy equal to Vitamin K Antagonists (VKAs) in the prevention of both stroke and major embolic events, net of a lower bleeding risk. This finding has also been established by both post-marketing phase IV trials and real-world evidence. However, no comparative study among the four DOACs has been conducted yet. In this chapter, we will assess the main features of each DOAC and their use in specific clinical scenarios, according to the most commonly used risk scale systems.