There were no significant differences in the rates of periprocedural stroke and death ( hazard ratio , 1.58 ; 95 % confidence interval , 0.33-7 .58 ; P = 0.57 ) , in immediate reoperation ( hazard ratio , 0.6 ; 95 % confidence interval , 0.16-2 .27 ; P = 0.45 ) , or in the 4-year risk of ipsilateral stroke ( hazard ratio , 1.23 ; 95 % confidence interval , 0.42-3 .63 ; P = 0.71 ) .