4.1 Study Limitations
The limitations of our study that need to be addressed. First, this was
a single-center retrospective study with a small sample size. Second, in
this study, we estimated the EOA using the PHT. There are several
methods that can be used to calculate the EOA, and, depending on the
cases, the PHT may not accurately reflect the actual EOA, which can
result in an inaccurate diagnosis of PPM. Third, because this study did
not have a randomized design, it is possible that unidentified
confounders or selection bias may have influenced the results. Fourth,
the preoperative values of the LA and LV diastolic diameters could not
be obtained in several patients. Thus, further prospective studies are
necessary to determine the impact of PPM on late outcomes.