F10 and atrial fibrillation: Novel oral anticoagulants that block coagulation factor Xa (fXa), such as apixaban, have been used for the prevention of stroke and systemic embolism in patients with atrial fibrillation (SPAF); however, despite their effectiveness, these therapies have high incidences of major and nonmajor clinically relevant bleeding (~ 15% for atrial fibrillation patients) [6–8].