This was attributed to a significantly lower frequency of residual more-than-mild aortic regurgitation ( 4.1 % vs 18.3 % ; RR , 0.23 ; 95 % CI , 0.09-0 .58 ; P < .001 ) and the less frequent need for implanting more than 1 valve ( 0.8 % vs 5.8 % , P = .03 ) in the balloon-expandable valve group .