The combined risk of fatal or nonfatal heart attack over the @-year period was highest in individuals with symptomatic versus asymptomatic stenosis ( @ % vs. @ % ; hazard ratio -LSB- HR -RSB- : @ , @ % confidence interval -LSB- CI -RSB- : @ to @ , p = @ ) and was higher in all patients treated with CEA ( HR : @ , @ % CI : @ to @ , p = @ ) .