Authors’ reply re: Vascular Control by Infrarenal Aortic
Cross-Clamping in Placenta Accreta Spectrum Disorders: description of
technique
Sir,
We thank Nieto-Calvache et al. for their insightful comments (1) on our
article (2). We agree with their point that the choice of vascular
control techniques should be determined by the topography and severity
of PAS disorders. We only performed aortic cross-clamping to selected
patients who were expected to bleed heavily during the cesarean
hysterectomy by prenatal ultrasonography. However, it is always possible
that prenatal imaging findings do not fully predict surgical conditions.
Although planning ahead, the final decision to perform aortic
cross-clamping (ACC) should be made during the cesarean hysterectomy,
after visualizing an extraordinary volume of tortuous vessels at the
lower uterine segment, parametrium, and/or bladder invasion with
uterovesical hypervascularity. If the PAS disorder is falsely diagnosed,
or the severity is less than predicted, the obstetricians can simply
proceed with conventional cesarean delivery or hysterectomy without
applying any additional procedure. The routine use of ACC techniques in
patients with mild PAS disorders is not recommended.
Balloon occlusion of the infrarenal abdominal aorta theoretically
provides the same level of pelvic perfusion blockage as our approach
(3). A major disadvantage of this procedure is that the catheter must be
placed before commencing the surgery (3), which may not be possible if a
prenatal diagnosis of PAS disorder is not made. On the other hand, if
the severity of PAS is overestimated, both the mother and the fetus
receive unnecessary radiation exposure from fluoroscopic catheter
insertion.
We do not have statistical data regarding additional PAS cases treated
without aortic cross-clamping in the same period. We conducted a
comparison between the subjects in this case series and our
previously-published historical controls (4). A potentially significant
decrease in surgical blood loss was found (2295.6 ± 2126.1 mL with ACC
vs. 4445.7 ± 3728.5 mL without intervention, p = 0.0084). Nevertheless,
we acknowledge this vague comparison without RCT is not scientifically
robust enough to draw a definite conclusion. PAS disorders encompass a
heterogeneous group of conditions characterized by different severity,
extent of invasion, and associated hypervascularity. All these factors
influence surgical difficulty and blood loss. Comparison of operative
blood loss in different series will subject to bias.
In our case series, six patients bled more than 4 liters because they
were the most severe cases with extensive uterovesical hypervascularity.
Even with ACC, the surgeries were still challenging, especially in
dissecting the bladder wall away from the extremely hypervascular lower
uterine segment. The surgical procedures were prolonged and extensively
neovascularization couldn’t be completely occluded due to the three
anastomotic pathways outside the vascular control provided by ACC (2).
An experienced multidisciplinary team approach (3) and delayed
hysterectomy at 4 to 6 weeks interval after cesarean delivery may
represent two of the optimum strategies for minimizing the degree of
hemorrhage in the most severe patients; the latter approach allows time
for uterine blood flow to decrease and for the placenta to regress from
surrounding structures in situations in which immediate hysterectomy is
deemed too dangerous (5).
M-M Choua,b, H-W Sub, M-J
Chenb, H-F Kungb, J-J
Tsengb, W-C Chenb, Y-F
Chenb
a Center for High-Risk Pregnancy and Maternal-Fetal
Medicine, Departments of Obstetrics and Gynecology, China Medical
University Hospital, Taichung, Taiwan
b Department of Obstetrics, Gynecology & Women’s
Health, Taichung Veterans General Hospital, Taichung, Taiwan