RESULTS	There were more primary safety events in the Watchman group ( 5.5 % per year ; 95 % confidence interval , 4.2 % -7.1 % per year ) than in the control group ( 3.6 % per year ; 95 % confidence interval , 2.2 % -5.3 % per year ; relative risk , 1.53 ; 95 % confidence interval , 0.95-2 .70 ) .\