F10 and atrial fibrillation: This applies specifically to the two landmark trials for approval of the factor Xa inhibitors apixaban and rivaroxaban—ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in AF) and ROCKET AF (Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in AF).5 6 In these trials, non-identical patient selection criteria resulted in much higher cardiovascular disease burden among patients in ROCKET AF compared with ARISTOTLE.