The rate of stroke or systemic embolism with rivaroxaban vs. warfarin was consistent among patients with SVD [ 2.01 vs. 2.43 % ; hazard ratio ( HR ) 0.83 , 95 % confidence interval ( CI ) 0.55-1 .27 ] and without SVD ( 1.96 vs. 2.22 % ; HR 0.89 , 95 % CI 0.75-1 .07 ; interaction P = 0.76 ) .