RESULTS	Major postoperative bleeding was observed in 2.3 % , 0.7 % , 4.3 % , 4.9 % , 5.1 % , and 1.9 % of patients receiving 5 , 10 , 20 , 30 , and 40 mg rivaroxaban , and 40 mg enoxaparin , respectively ( n = 845 , safety population ) , representing a significant dose-response relationship ( P = 0.0391 ) .\