Discussion
The surgical management of aortic arch hypoplasia with associated
intracardiac anomalies is a challenge in neonates and infants. According
to intracardiac anomalies, palliation or total repair in addition to
arch repair is controversial. Moreover, significant proximal transverse
aortic arch obstruction is rare than the distal arch and isthmus
hypoplasia, but almost always requires a surgical approach via a
sternotomy 1. In our cohort, all patients had tubular
arch hypoplasia, so we performed all arch reconstructions via sternotomy
and enlarged the aortic patches to the midportion of the ascending
aorta. We attempted to perform total intracardiac repair in all
biventricle patients, but in single ventricle patients and biventricle
patients with preoperative comorbidities we performed pulmonary artery
banding. From this point of view, BSA values during surgery were
significantly lower in the palliation group and the number of patients
weighing <2.5 kg was higher.
Several techniques and patch types have been proposed through the years
for repair of aortic arch obstructions, and recurrent obstruction in the
correspondence of the aortic arch surgery, is the most frequently
reported complication, with a hugely variable incidence reported from 2
to 38% 5-7. Roussin and colleagues presented that
aortic arch repair associated with pulmonary autograft patch
augmentation resulted in superior midterm outcomes, thus reducing the
risk of recorctation and tracheobronchial compression in comparison to
patch aortoplasty with homograft and pericardial patch augmentation8.Morales and colleagues presented excellent results
with 100% freedom from arch reintervention during a 5-year follow-up in
neonates with interrupted aortic arch using aortic arch advancement
technique 9. On the other hand, Gaynor and colleagues
published no difference regarding the incidence of reintervention by
patch reconstruction of the arch (20%) or resection with end-to-end
anastomosis (25%)10. In our technique, distal
descending aorta was anastomosed to the aortic arch to form a native
posterior wall, and patch augmentation was extended to the midportion of
the ascending aorta. In our opinion, it is safer not to use too long and
wide patches, and to extend the patch like us. We preferred
glutaraldehyde treated autologous pericardium in 21 patients, bovine
pericardium in 19 patients, porcine pericardium in 20 patients as a
patch. Rigit patches in particular such as grafts can cause stenosis by
pushing the proximal and distal aorta.
All of our patients had tubular arch hypoplasia in this study, which was
calculated to be a risk factor for recoarctation by Dodge-Khatami and
colleagues in a 40-year review of patients undergoing coarctation repair11. Similarly, Bernabei and colleagues presented a
higher incidence of restenosis rate with neonatal arch hypoplasia as
compared with arch interruption or the hypoplastic left heart syndrome7. Interestingly, all patients in that study underwent
arch reconstruction with autologous pericardium. One- and three-year
freedom from recoarctation was 93 and 69%, respectively, and the
authors concluded that the use of autologous pericardium in aortic arch
reconstruction procedures is valid and associated with an acceptable
incidence of recurrent arch obstruction 7. In our
study, 10 (20.8%) patients required reintervention due to distal
recoarctation, seven of them treated with successful aortic balloon
angioplasty, but 3 required surgical reintervention. We performed
resurgery via left thoracotomy in 3 patients using bovine or porcine
pericardium. We observed only one (2%) proximal restenosis, probably
due to the particular shape of the aortic arch, and we performed
reoperation via median sternotomy. We believe that our low proximal
restenosis rate depends on our technique that extends the patch to the
middle of the ascending aorta. Furthermore, with the use of patch
enlargement, we did not observe bronchi or trachea compression described
as a possible complication of end-to-end anastomosis12.
The arch hypoplasia, interruption, or coarctation is efficiently dealt
with at the time of the ASO while working through a median sternotomy.
It is generally possible to perform a direct
anastomosis for interruption or coarctation with mild tension on the
anastomosis. On the other hand, the aortic arch hypoplasia requires an
additional longitudinal patch-plasty. This has the advantage of
enlarging the size of the ascending aorta, thus facilitating a
tension-free neoaortic anastomosis; it achieves an aortic arch of
adequate size. Huber et al. conducted a study on 22 patients who
underwent ASO and arch repair with 18,1 % overall mortality, and 3
patients required ECMO. Sixteen of 22 patients had arch hypoplasia, and
remaining patients had coarctation or IAA, and Huber et al. reported a
44% rate of arch reintervention 13. Vouhe´’s group
described a 76% actuarial survival rate in 38 patients who underwent
ASO with arch repair, mentioning arch reinterventions in three patients
(7.8%)14. By contrast, Planche´’s group conducted a
study on 67 patients who underwent one-stage repair with either
end-to-end (35 patients) or patch enlargement of (32 patients) for AAO
relive. Overall, actuarial survival in this series was 94% in the 32
patients and 75% in the 35 patients over 10 years, and re-interventions
required in 15 patients (22%) for recoarctation 15.
In our cohort, 11 patients underwent ASO and arch repair with 18.8%
overall mortality; one of them required ECMO, two patients died due to
sepsis on the postoperative course, and only one patient (11%) required
reintervention for recoarctation during the follow-up. Our mortality and
reintervention rates were similar to the literature for this complicated
group. We considered that the one-stage-repair of transposition complex
and aortic arch hypoplasia showed good survival results for these highly
complex congenital anomalies in high-volume hospitals.
More complex pathologies or functional single ventricle with arch
hypoplasia showed high morbidity or mortality rates16. Historic outcomes of PAB + COA repair have been
unfavorable and associated with high hospital death, reduced progression
toward subsequent palliative stages, and overall low survival17,18. Franklin and colleagues found that
survival after PAB + COA repair was 44% at 1 year and 22% at 5 years,
and in another study, they found that Fontan candidacy was only 8%17,18. In our study, in Group 1 (PAB +arch repair),
mortality rate was 34.8% (8/27), and 62,5% (5/8) of them had
functional single ventricle. On the other hand, Poirier et al. conducted
a study on 37 children who had arch hypoplasia and biventricular hearts,
and they reported no postoperative deaths with isolated aortic arch
hypoplasia patients. However, the operative mortality for their total
cohort of patients was 13.5% 19. Karl and associates
have reported similar results of the combined arch and intra-cardiac
repair with a 13% operative mortality rate in a group of 15 infants who
underwent a single-stage repair 20. These mortality
rates were similar to our single-stage repair group, with a mortality
rate of 10.8%. In our study, only 6 cases with biventricular heart
underwent isolated arch reconstruction with no operative mortality.
Although the duration of cardiopulmonary bypass time and cross clamp
time were significantly higher in the single-stage repair group,
postoperative mortality, delayed sternal closure time, VAC treatment
usage rate, sudden cardiac arrest rate, and postoperative low cardiac
output rates were significantly higher in the palliation group. In our
perspective, these results shows the importance of single stage total
repair, and the adverse effect of the pallation to the outcomes.
In neonates and some infants, low cardiac output can persist after
coarctation repair due to
preoperative LV dysfunction 21. Lim et al. conducted a
study on 69 neonates or infants who underwent single-stage total repair
of the aortic arch anomaly using regional perfusion. They reported only
four patients (5.7%) had postoperative low cardiac output syndrome, and
all of them had poor preoperative conditions 21. In
our study, 8 patients (13.3%) had postoperative low cardiac output
syndrome, and this was significantly higher in our palliation group
(p=0.022). Among 8 patients, 7 require mechanical ventilatory support,
and 3 of them had poor ventricular function requiring inotropic in the
preoperative period. Only one patient did not need any support
preoperatively, but he was also premature.
We only used a direct cannulation method through the innominate artery,
even in the small neonates, instead of using a polytetrafluoroethylene
graft. We considered it a basic and applicable method which did not
conceal the surgical area. Moreover, there was no cannulation-related
complication, such as stenosis or intimal injury in our cohort. Usually,
the size of the innominate artery was adequate for cannulation, and we
easily advanced the 8Fr arterial cannula. We used ACP perfusion during
the repair of aortic arch hypoplasia with a flow rate of 40-50 ml/kg/min
in order to maintain a perfusion pressure of 50-60 mmHg, and all
patients were monitored by near-infrared spectroscopy (NIRS). In our
series, early postoperative minor neurologic complications as seizures
occurred in three patients (5%), which is better than the reported
rates (4-25%) in total circulatory arrest groups 22.
Any abnormality was not detected in these patients on CT and
electroencephalogram, and fortunately, all patients recovered entirely
by anti-epileptic therapy, but the long-term complications such as
neuro-developmental abnormalities need to be evaluated further.
Some reports suggested that the higher hematocrit level would be
beneficial on neurologic outcomes after the TCA or low flow bypass23. But there was some controversy on the optimal
hematocrit level, and there has been no gold standard. In our cohort, we
maintained a hematocrit level at around 30 %, and we believe that this
is one of the reasons for not seeing a major neurological complication.
Pigula et al. reported that the somatic perfusion through various
collaterals was maintained during low flow regional perfusion with a
flow rate of 30– 40 ml/kg per min and suggested that the support of the
subdiaphragmatic viscera should improve the ability of neonates to
survive the postoperative period 24. Lim et al.
conducted a study on 48 neonates who underwent aortic arch
reconstruction operation using regional perfusion without circulatory
arrest. Their mean radial artery perfusion pressure was about 40-50
mmHg, the mean duration of regional perfusion time was 33±16 min, and
renal insufficiency occurred in only 4.2% (2/48) of patients in the
postoperative course 16. In our cohort, the mean
radial artery perfusion pressure was about 50-60 mmHg, the mean duration
of antegrade cerebral perfusion time was 22.4 ±7.4 min, and renal
insufficiency occurred in only 5% (3/60) of patients in the early
postoperative period. On the other hand, Kreuzer et al. and Hammel et
al. reported that 1,7% and 5% of postoperative acute renal failure
rate, respectively, with double arterial cannulation, and they reported
lower adverse events were observed by additional descending aorta
cannulation 25,26. We believe that the direct
comparison of the results for renal complications was inappropriate
because of the various preoperative conditions, but we considered that
such a high flow rate would be beneficial in the functional recovery of
somatic organs besides cerebral protection.
The retrospective and single-center study design aspects are the main
limitation of this study. Studies with multiple centers, including
various types of congenital heart disease and long-term outcomes, are
needed to demonstrate the surgical results of aortic arch hypoplasia.
In conclusion, aortic arch reconstruction for tubular arch hypoplasia in
neonates and infants with or without associated intracardiac lesions can
be repaired by single-stage repair with acceptable early and mid-term
results. On the other hand, palliation with arch repair should be
considered in biventricular neonates with significant preoperative
comorbid conditions, and in single ventricle neonates.