At 18 months , the rate of the first coprimary efficacy endpoint ( composite of stroke , systemic embolism [ SE ] , and cardiovascular/unexplained death ) was 0.064 in the device group versus 0.063 in the control group ( rate ratio 1.07 [ 95 % credible interval ( CrI ) : 0.57 to 1.89 ] ) and did not achieve the prespecified criteria noninferiority ( upper boundary of 95 % CrI 1.75 ) .