Limitations
First, this study had the typical limitation of a retrospective study. The indication of TAVR for bicuspid aortic valve instead of SAVR, the choice of THV type or size may differ among the centers. Second, there have been published two different methods of measuring MS, and the gold standard was still controversial. The results that MS was not significantly different between the 2 groups might be different when the other way is employed. Third, as to clinical outcomes other than CD, the results should be interpreted with care, since the study cohort excluded the patients who potentially develop complications. Two implantation failures and no intraprocedural death were excluded from the BAV cohort, and 2 implantation failures 2 intraprocedural death were excluded from TAV group. Fourth, PS matching was modeled with the TAV cohort from single-center, while the BAV cohort consisted of the patients from 3 centers. Also, even though the PS matching has balanced patient characteristics, several factors were not included in the model and unmeasured confound factors may not be eliminated.