Results
During the study period, 263 caesarean sections were performed. General
anaesthesia was used in 47 (17.9%) cases and neuraxial anaesthesia was
used in 214 (81.3%) cases. Two parturients received both general and
spinal anaesthesia. Since the reasons for using both techniques were not
clear, these parturients were excluded from the analysis. In the
neuraxial anaesthesia group, simple epidural anaesthesia was performed
in 24 (11%) cases and spinal anaesthesia with or without epidural
anaesthesia in the remaining 190 (89%) cases. The characteristics of
the study patients are shown in Table 1. The general anaesthesia group
included more parturients with NYHA class III–IV disease, mWHO class IV
disease, systemic ventricle EF <50%, and emergency caesarean
section. In the past, parturients more frequently received general
anaesthesia at delivery. More recently, parturients frequently received
neuraxial anaesthesia at delivery. At delivery, gestational age was
lower in the general anaesthesia group than in the neuraxial anaesthesia
group. Indications for caesarean section differed significantly between
the 2 groups. The amount of missing data was expressed in Table S1.
Postpartum Outcomes
Postpartum outcomes are shown in Table 2. There were no deaths or
respiratory events. Cardiovascular events were more common in the
general anaesthesia group (14.9%) than in the neuraxial anaesthesia
group (7.9%), but this difference was not significantly different
(P =0.16). Heart failure occurred in parturients with Eisenmenger
syndrome (n=1), transposition of the great arteries (TGA) repaired with
the Jatene procedure (n=2), TGA functionally repaired with the Mustard
procedure (n=1), repaired ventricular septal defect (VSD) (n=2),
bicuspid aortic valve (BAV) with aortic regurgitation (n=1), and
unrepaired Epstein anomaly (n=1). Pulmonary hypertension occurred in
parturients with Eisenmenger
syndrome (n=3), repaired atrioventricular septal defect (n=1), and
repaired VSD (n=1). Arrhythmia occurred in parturients with Fontan
circulation (n=2), repaired tetralogy of Fallot (n=2), BAV with aortic
dilation (n=1), coarctation of the aorta (n=1), and Kawasaki disease
with coronary aneurysm (n=1). Heart failure occurred more frequently in
parturients with higher NYHA class or mWHO class. Three parturients in
the general anaesthesia group required postpartum transfusion for
intraperitoneal bleeding after administration of anticoagulants because
of a mechanical valve.
Results from mixed-effects logistic regression models with a random
intercept for each mWHO class for maternal cardiovascular risk are shown
in Table 3. Compared with neuraxial anaesthesia, general anaesthesia was
not significantly associated with composite postpartum cardiovascular
events (odds ratio [OR], 1.00; 95% confidence interval [CI],
0.30–3.29).
Neonatal Outcomes
Neonatal outcomes are shown in Table S2. Three newborns died of the
following causes: intraventricular haemorrhage probably due to maternal
anticoagulation with the mechanical valve during pregnancy (n=1), after
surgery to correct neonatal CHD (n=1); immediately after birth due to
severe neonatal CHD (n=1). The general anaesthesia group had a
significantly higher percentage of neonatal intubations (53.2% vs.
7.0%, P <0.001), Apgar scores <7 at 1 or 5
minutes (57.4% vs. 2.8%, P <0.001) and composite
neonatal outcome (63.4% vs. 8.9%, P<0.001). Mixed-effects
logistic regression models with a random intercept for each mWHO class
for maternal cardiovascular risk revealed that general anaesthesia is
significantly associated with a higher rate of composite neonatal
outcomes (OR, 13.3; 95% CI, 5.52–32.0) (Table 4).
Sensitivity analysis
In the sensitivity analysis with date of delivery as a confounding
factor, maternal outcomes remained not significantly associated with
general anaesthesia (OR, 0.76; 95% CI, 0.19–3.00). Results were also
unchanged in the sensitivity analysis where emergency caesarean section
status was changed to gestational weeks at delivery as a potential
confounding factor in the model (OR, 0.51; 95% CI, 0.24–1.11).
Regarding neonatal outcomes, in the sensitivity analysis with date of
delivery as a confounding factor, composite neonatal outcomes remained
associated with general anaesthesia (OR, 8.84; 95% CI, 3.54–22.1).
Results were also unchanged in the sensitivity analysis where emergency
caesarean section status was changed to type of indication for caesarean
section as a potential confounding factor in the model (OR, 12.8; 95%
CI, 5.49–30.0). In the propensity score analysis using IPTW, composite
postpartum cardiovascular events remained not significantly associated
with general anaesthesia (OR, 0.51; 95% CI, 0.12–2.20) and composite
neonatal outcomes remained significantly associated with general
anaesthesia (OR, 4.56; 95% CI, 1.48–14.0). The c-index for the
logistic regression model that was used to calculate propensity scores
was 0.90.