Commentary
We read with great interest Ayati et al. [1] recent review article
abating on a rare occurrence of type A aortic dissection (TAAD) during 8
week gestational phase in a primigravid. Its unequivocal that there is
an unmet clinical need in aortic practice on this entity. TAAD during
pregnancy is a life-threatening event for both the mother and the unborn
baby. Furthermore, pregnancy has been recognized as an independent risk
factor for TAAD, postulated to be due to physiological changes that
cause hyperdynamic circulation. The authors are to be commended on their
comprehensive literature search and methodology as well as their
detailed approach to describing the relationship between aortic
dissection and pregnancy and to summarising its predisposing factors,
imaging modalities, surgical treatment and techniques, medication
challenges and future directions.
The challenges faced when dealing with TAAD in pregnancy are
multifaceted and require an individualised and tailored approach.
Despite this, challenges in implementing management strategies in the
form of operative techniques and cardiopulmonary bypass (CPB) use place
the foetus at a significant and must be approached with great caution.
The general consensus is not to operate or avoid surgery in the first
trimester. But if the patient is unstable, the risk has to explained and
them mother to undergo central aortic repair. Few authors even advise
termination of pregnancy and central aortic repair [2].
In agreement with Ayani et al. [1], the choice of imaging modality
is one to be taken with care and consideration of the foetus’s health.
However, imaging-posed additional radiation exposure and teratogenicity
of the contrast material, such as iodinated- or Gadolinium-based
contrast media, must be avoided [3][4]. Thus, we recommend an
existential ultrasonography and MRI and in line with what is recommended
radiological methods in the literature for any pregnant woman [4].
The choice of treatment for TAAD depends on the extent of the disease,
this is almost always surgical [5]. Despite the evolution of
surgical techniques as well as pre- and post-operative care, the
surgical mortality rate for TAAD still remains highly variable depending
on the technique used. There is a substantial debate as to limit
surgical extent to saving the patient with limited aortic approach
versus the more aggressive extended approach. If only the ascending is
pathological, the surgeon can perform a hemiarch replacement, however,
if the aortic arch is contemplated in the pathology, the surgical
approach changes to whether or not to adopt the frozen elephant trunk
(FET) technique. Both of the above procedures involve the use of
cardiopulmonary bypass (CPB) and both can be combined with a Bentall or
David procedure to replace or repair the aortic valve
[6][7][11]. In the case that the aortic valve needs to be
replaced, the choice of prosthetic valve, whether mechanical or
biological, needs to be taken with care on a case-by-case basis [1].
The other dilemma that compounds the scenario is the question of when to
deliver the foetus as essentially this varies around the age of the
foetus, with some authors such as Zeebregts et al. [8] suggesting
the option of concomitant delivery between 28 and 32 gestational weeks
should foetal maturity have occurred. The European Society of Cardiology
recommend delivery from 26 gestational weeks when foetal maturity is
likely to have been reached [9]. On the other hand, Yates et al
[10] reported their series of 11 pregnant patients (19 gestational
weeks, range 16-21 weeks) who underwent emergency cardiac surgery. The
authors succeeded with no maternal mortality but reported a foetal
mortality rate of 27% (3/11) within 1 week of surgery with the
remaining 8 babies born at full-term.
Initiating CPB requires alterations in the coagulation factors,
complement cascade activation and hypothermia, which can have
detrimental effects on the placenta and, in turn, the foetus [1]. A
2018 meta-analysis combined data from 10 studies on maternal and foetal
outcome after open heart surgery during pregnancy. The pooled results
showed 11.2% and 33.1% rates of maternal and pregnancy loss,
respectively [12]. The 33.1% foetal mortality rate is in line with
that found in Weiss et al. (30%) [13], however, here the authors
reported a lower maternal mortality rate of 6%. In addition, Weiss et
al. [13] showed that aortic dissection is associated with the
highest mortality amongst the causes for cardiac surgery during
pregnancy. Although Ayani et al. [1] summarised intraoperative
measures, particularly concerning CPB, this does not indicate that any
surgical approach can be diligently considered as safe or risk-averse,
as life-threatening risks do exist on both the mother and her foetus.
Ayani et al. [1] rightly stressed on the importance of carefully
coordinating medications, namely hypertension drugs and anticoagulants,
as this can have a serious impact on outcomes for both patients (mother
and foetus). However, this is not without limitations, especially in the
peri-operative period. Alas, beta‐blockers have been shown in several
studies to have untoward effects in pregnancy, such as intrauterine
growth restriction and foetal bradycardia [9]. A study on
celiprolol, however, had a decrease of arterial events (20%) in a
randomized control trial compared with control (50%), but this has not
been demonstrated in patients with aortic disease [14].
In conclusion, TAAD in pregnancy adds an extra level of complexity to an
already complex process. Yet, optimal outcomes can be achieved with
planning involving accurate diagnosis, safe imaging, modern surgical
techniques, and tight medication control. There is no easy answer to
such scenarios, but we remain dutiful in promoting patient-centred and
tailored care to achieve optimal results.