Study limitations:
This was a retrospective study, and therefore there was considerable
variation in the timing of echocardiographic studies. However clinical
practice would dictate timing to coincide with trimester. At our centre,
it is a routine practice to obtain a baseline echocardiogram at the time
of the referral and also a repeat echocardiogram during
2nd trimester in women with LVOTO/AS. This likely
mitigates some of the issues surrounding potential selection bias.
Secondly, our study had a very small number of women with moderate or
greater LVOTO/AS. This may potentially explain why the event rates for
obstetrical and fetal/neonatal outcomes were also low. Finally, we
assessed only the longitudinal strain, without measuring the
circumferential or the radial strain. However, we feel that the
longitudinal strain is the most clinically relevant marker, and the
other types of strain are less applicable in clinical practice.