There was no difference in the primary outcome between radial and femoral access by operator volume : high-volume operators ( HR : 0.79 ; 95 % CI : 0.48 to 1.28 ) , intermediate ( HR : 0.87 ; 95 % CI : 0.60 to 1.27 ) , and low ( HR : 1.10 ; 95 % CI : 0.74 to 1.65 ; interaction p = 0.536 ) .