The incidences of recurrent VTE were also similar in rivaroxaban ( 54 of 3,501 , 1.5 % ) and enoxaparin/VKA ( 69 of 3,436 , 2.0 % ) patients who did receive prestudy heparin ( adjusted HR = 0.74 ; 95 % CI = 0.52 to 1.06 ; pinteraction = 0.32 ) .