The mean ( SD ) change in systolic blood pressure at 6 months was -14.1323.93 mm Hg in the denervation group as compared with -11.7425.94 mm Hg in the sham-procedure group ( P < 0.001 for both comparisons of the change from baseline ) , for a difference of -2.39 mm Hg ( 95 % confidence interval [ CI ] , -6.89 to 2.12 ; P = 0.26 for superiority with a margin of 5 mm Hg ) .