PALLIATIVE ARTERIAL SWITCH OPERATION AS AN ALTERNATIVE FOR SELECTED
CASES:
SINGLE CENTERS‘ EXPERIENCE AND MID TERM RESULTS.
Okan Yurdakök MD1, Murat Çiçek MD1, Oktay Korun MD1, Fırat Hüsnü Altın
MD1, Mehmet Biçer MD2, Yasemin Altuntas MD3, Emine Hekim Yilmaz MD 3,
Numan Ali Aydemir MD1, Ahmet Şaşmazel MD1.
- Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and
Research Hospital, Department of Pediatric Cardiac Surgery,
Istanbul, TR
- Kartal Kosuyolu Training and Research Hospital, Department of
Pediatric Cardiac Surgery,
Istanbul, TR
- Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and
Research Hospital, Department of Anesthesiology,
Istanbul, TR
- Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and
Research Hospital, Department of Pediatric Cardiology,
Istanbul, TR
Short Title: Palliative Arterial Switch Operation
*The article was presented in a local conference for Turkish pediatric
cardiology and cardiac surgery community
Corresponding Author: Okan Yurdakok
Siyami Ersek Hastanesi, Tıbbiye Caddesi,
Uskudar, Istanbul
Email:
okanyurdakok@gmail.com
Fax: +90 (216) 418 96 49
ABSTRACT
Introduction and Objective: There are various management options for
newborns with single ventricle physiology, ventriculoarterial
discordance and subaortic stenosis (SOS), classically involving the
early pulmonary banding and aortic arch repair, the restricted
bulboventriculer foramen(BVF) enlargement or the Norwood and the Damus
Kaye Stansel (DKS) procedures. The aim of this study is to evaluate the
midterm results of our clinical experience with palliative arterial
switch operation (pASO) for this subset of patients.
Method: We hereby retrospectively evaluate the charts of patients going
through pASO, as initial palliation through Fontan pathway, starting
from 2014 till today.
Results: 10 patients underwent an initial palliative arterial switch
procedure. 8 of 10 patients survived the operation and discharged. 7 of
10 patients completed stage II and 1 patient reached the Fontan
completion stage and the other six of ten (6/10) patients are doing well
and waiting for the next stage of palliation. There are two mortalities
in the series (2/10) and one patient lost to follow-up (1/10).
Conclusions: The pASO can be considered as an alternative palliation
option for patients with single ventricle physiology, transposition of
the great arteries and systemic outflow obstruction. It not only
preserves systolic and diastolic ventricular function, but also provides
a superior anatomic arrangement for following stages.
Keywords: Congenital Heart Disease, Single Ventricle, Arterial Switch
Operation
1-INTRODUCTION
Univentricular heart patients, combined with ventriculoarterial
discordance and subaortic stenosis is a rare combination of anomalies
and the choice between surgical options for better outcomes is still not
clear in the current literature.
The options for traditional first stage of palliation for functional
single-ventricle lesions with transposition of the great vessels and
systemic outflow obstruction has been pulmonary artery banding and
aortic arch reconstruction123, enlargement of the
restricted bulboventricular foramen (BVF)4, and the
Norwood5 or the Damus-Kaye-Stansel
(DKS)6 procedures.
Since there is still limited experience on the use of palliative
Arterial Switch procedure(pASO)789 as the initial
stage of palliation for the functional single ventricles, this study is
the report of our institutions‘ clinical experience with this cohort of
patients and their midterm results.
2-MATERIALS AND METHOD:
The study includes retrospective analysis of the institutes‘ clinical
experience on patients with Palliative Arterial Switch operations (pASO)
for single ventricle anatomy with Transposition of the Great Arteries
(TGA) and systemic outflow tract obstruction (SOTO), starting from 2014.
Approval was obtained by the Institutional Review Board. The surgical
database was reviewed for all arterial switch cases performed on
functional single ventricles. All patients with a functional
single-ventricle lesion and systemic outflow tract obstruction (SOTO)
(valvar aortic stenosis, subaortic stenosis, or a restrictive
bulboventricular foramen), who underwent an arterial switch procedure as
initial palliation, and had operative records available for review were
included in the study. Charts were reviewed to evaluate patient
demographics, pre-operative condition, cardiac anatomy, pre-operative
and post-operative echocardiograms, operative data and most recent
follow-up data.
SURGICAL TECHNIQUE:
Following median sternotomy and heparinization, brachiocephalic artery
and bicaval cannulations were made to go on cardiopulmonary bypass (CPB)
and the patients were cooled down to 28º C. Patent ductus arteriosus
(PDA) was ligated proximally on aorta and distally on pulmonary artery
and divided. Descending aorta was dissected distally. Aorta was cross
(X) clamped and heart was arrested with antegrade Del Nido cardioplegia.
The X clamp was moved back to the innominate artery, proximal to the
arterial cannulation site, the distal ascending aorta was clamped and
the left carotis and left subclavian were snared to continue with
antegrade cerebral perfusion. The hypoplastic arcus aorta was
reconstructed either by using autologous pericardium treated with
gluteraldehyde for 2 minutes or without any patch augmentation. The
coronary arteries were transferred to the neoaorta, using the standart
open technique with medially based trapdoor flaps as for the simple
arterial switch operation. LeCompte maneuver is used for all patients.
Pulmonary artery reconstruction was made using a generous autologous
pericardium patch to prevent the upward compression of the
neoconstructed aorta. And the proximal augmented pulmonary artery root
with a functioning neopulmonary valve is connected to the distal
pulmonary artery bifurcation. X clamp was removed after dearing. After
weaning from cardiopulmonary bypass, considering the size of the
bulboventriculer foramen, the pulmonary artery was left as it is, when
no further interventions were needed for a balanced circulation; but
when necessary, either a Blalock-Taussig shunt to provide adequate
pulmonary blood flow or a pulmonary artery banding, to prevent excessive
pulmonary blood flow, was used, as indicated according to peri-operative
measurements.
Statistical Analysis
Standard descriptive statistical analyses were performed. Means, medians
and ranges were used to describe continuous variables. Frequencies and
percentages were used for categorical data. All analyses were conducted
with Microsoft Excel (Microsoft Corp, Redmond, Washington).
RESULTS
From January 2014 through today, 10 patients have undergone Palliative
Arterial Switch operation (pASO) for the palliation of patients with
univentricular anatomy, the transposition of the great arteries and
systemic outflow tract obstruction (Table1). The mean age of the
patients at the time of first operation was 42.5 days (ranging 7-155).
6/10 (60%) of the patients were boys. The preoperative diagnosis
through Transthoracic Echocardiography (TTE) were Tricuspid Atresia (TA)
with TGA and systemic outflow obstruction (n=5, 5/10) and Double Inlet
Left Ventricle (DILV) with TGA and systemic outflow obstruction (n=5,
5/10).
Average X clamp time was 108 minutes (ranging 88 to 142). All patients
had aortic arch reconstruction with/without autologous pericardium,
treated with glutaraldehyde. 1/10 of the patients (10%); being the
first patient in the series, received a Blalock-Taussig shunt, due to
low oxygen saturations when coming off bypass. 7/10 (70%) of the
patients, received a loose pulmonary artery banding to balance the
pulmonary artery blood flow when coming off bypass and adjusted
according to oxygen saturations and blood pressure measurements. 2/10
patients (%20) in the series did not need any further interventions for
adequate pulmonary blood flow management, while weaning from CPB. Mean
intensive care unit (ICU) and hospital stay intervals were 9 (ranging
5-16) and 16 (ranging 8-38) days, respectively. There were 2 (2/10)
mortalities in the series. The first patient was patient #3, who had a
palliative arterial switch without any pulmonary banding and the
post-operative course was uneventful initially, but had a persisting
arrythmia on day #4, deteriorated and did not respond to any
interventions and deceased. The second patient was patient #5, who had
a usual palliative arterial switch operation with a pulmonary banding,
but needed a re-exploration on the first post-operative night on bedside
in the ICU due to metabolic acidosis and was put on ECMO for recovery
but did not respond to further interventions and died on POD#12. And
the first patient in the series who had a pASO with the BT shunt, had a
long postoperative course which included a tracheostomy, but discharged
after 2 months and lost follow-up after the first post-operative clinic
visit, since the patient was initially accepted from a nearby country
and went back home after treatment.
7 of 10 patients reached stage II and had a cardiac catheterization
before the Glenn operation. The mean pulmonary artery pressures (mPAP)
were acceptable, only one patient needed tightening of the previous band
during the operation. And another patient underwent balloon angioplasty
of the distal arch for residual gradient during the catheterization
before stage II. 1/7 patients needed an aortic arch reconstruction
concomitant to Glenn operation and and 2/7 of patients needed pulmonary
artery reconstruction as well. The AV valves and semilunar valves were
functioning well, the bulboventriculer foramen were also evaluated with
transthoracic echocardiography and catheterization and no further
interventions were needed at this stage (Picture 1). The ventricular
functions were well preserved.
Only 1 patient reached the Fontan completion stage yet and preoperative
cardiac catheterization showed unobstructed arch, good ventricular
function and reasonable valve coaptation. mPAP was 11 with satisfactory
pulmonary artery distribution and the patient had an uneventful Fontan
operation with an extracardiac conduit.
DISCUSSION
The earliest presentation of the palliative arterial switch procedure in
the literature was by Freedom and colleagues in 19807,
who described 2 patients with tricuspid atresia that underwent arterial
switch and simultaneous Fontan procedure. Karl and associates later
developed the technique and reported 6 patients with univentricular
hearts and subaortic stenosis, 2 of them went on to BDG and 1 patient
underwent a Fontan procedure8. Lacour-Gayet and
colleagues, also reported 7 patients who underwent palliative arterial
switch with good short-term results9, but Fontan
palliation stage and suitability has not been reported.
The potential advantages of the pASO are well presented
earlier1011; we also believe that the basic principle
of this operation is beneficial to ”switch” the subaortic obstruction
into a subpulmonary obstruction and create a laminar flow through the
systemic outflow tract. The relief of subaortic stenosis, thus
preventing myocardial hypertrophy of the single ventricle and further
restriction of the BVF. pASO also prevents diastolic dysfunction of the
single ventricular chamber by keeping a functioning valve in the
pulmonary position. The connection of the rudimentary ventricular
chamber to the pulmonary artery trunk creates a natural protection for
the pulmonary vascular bed through the restrictive bulboventricular
foramen101112. And another potential advantage is
using the LeCompte maneuver, which not only prevents the compression of
the pulmonary arteries under the enlarged root of posteriorly dislocated
neoaorta, but also making it easier to reach the branch pulmonary
arteries, to address the future complications at following stages, if
necessary1011. There is also decreased need for a
systemic to PA shunt, as a shunt which carries the risk of shunt
occlusion, distortion of PA anatomy, and decreased diastolic pressure
with potentially poor coronary perfusion.
The main concern with pASO is generally the unpredictable pulmonary
blood flow through the ventricular septal defect. Even if the criteria
for diagnosis of SAS and restrictive bulboventriculer foramen like the
BVF size being less than the diameter of the aortic root either by
echocardiography or cardiac catheterization or any measured
ventriculo-aortic gradient (above 10-20 mmHg) was helpful but considered
as unreliable by us and others to be clinically
significant81314. These preoperative measurements of
the BVF and the aortic annulus circumference might estimate the
likelihood of a restriction probability of the blood flow to the
pulmonary bed and help to predict the need for an additional
intervention for maintaining adequate pulmonary blood flow, when coming
of cardiopulmonary bypass.
And another aspect to keep in mind when evaluating the bulboventricular
foramen preoperatively is, if the aortic arch is hypoplastic, this might
point to the BVF is going to be also restrictive after birth, since it
was not providing enough flow for the arch to grow during pregnancy. It
has been suggested that the signs of subaortic stenosis in utero can
result in subnormal aortic flow, causing underdeveloped aortic arch and
even favoring the development of coarctation.
The aim of initial palliation for infants with univentricular hearts,
transposition of the great arteries and systemic outflow tract
obstruction is basically to provide unrestricted systemic and adequate
pulmonary blood flow. The primary objective is carrying the patient
safely to the next stage after initial palliation. Either a
bidirectional Glenn operation (BDG) or a Fontan procedure, both require
the control of excessive pulmonary blood flow to prevent future
pulmonary vascular resistance and maintain adequate pulmonary blood flow
to provide satisfactory oxygen saturations. The strategy also needs to
preserve the univentricular systolic and diastolic function by
addressing the systemic outflow obstruction1516.
Various other management options to address these conflicts in this
group of patients with single ventricle, ventriculoarterial discordance,
and subaortic stenosis have included enlargement of the
BVF4, pulmonary artery banding with arch
repair123, modifications of the DKS6or Norwood5 procedure.
Although pulmonary artery banding has been advocated as initial
palliation in the neonatal period to protect the pulmonary vasculature
in patients with functional single ventricle, there is a tendency for
spontaneous narrowing of the BVF by itself17 or
accelerated by the immediate reduction in diastolic heart volume after
an effective PAB. In the longer term there is also further reduction in
BVF size due to PAB-related myocardial hypertrophy3.
Subaortic obstruction may complicate the future Fontan palliation by
inducing ventricular hypertrophy1516, leading to
subendocardial ischemia and diastolic dysfunction and this has led some
groups to abandon pulmonary artery banding as palliation when subaortic
stenosis is present or anticipated.
The key anatomical feature is the BVF in the UVH patients with subaortic
stenosis, which is mostly a slit-like or buttonhole like opening with a
completely muscular rim and estimation of the size of the ventricular
septal defect carries utmost importance. Preoperative echocardiography
is often unreliable due to the mentioned anatomic features above, but
when the size of the VSD is less than the size of the aortic annulus
with a measurable gradient from the dominant ventricle to aortic annulus
by Doppler echocardiography( >10-20
mmHg)813 and when accompanied with an underdeveloped
hypoplastic aortic arch; then the BVF can be considered as restrictive
and needs to be addressed accordingly.
The surgical enlargement of the BVF and subaortic resection can be
technically quite difficult in the young infant or neonate; risking
injury to the conduction system which appears to be close to the
inferior rim of the BVF or aortic valve might also be in jeopardy, if
the surgical enlargement is carried on through the aortic annulus.
Another surgical option that was employed for SAS with enlargement of
the BVF is the division and resection of additional subaortic muscle
bands4. Despite potential complications of heart
block, coronary injury, and recurrent SAS this approach has been used
extensively in many centers.
The DKS procedure was originally described for biventricular repair of
transposition of the great arteries18. The indications
were then extended for use in single-ventricle palliation. The
variations of this technique19 and the Norwood
operation have been used to address the sub-aortic obstruction in this
subset of patients with single ventricle and transposed great arteries
as the primary palliation to end up with Fontan
completion6.
The operative mortality for the Norwood and the DKS procedures vary in
the current literature between institutes, depending on the era of
reporting, the weight and the anatomy like factors related to the
patient undergoing the procedure, and other factors
etc.1320 but considering the overall Norwood
procedures’ mortality being reported as high as 10-30%, the palliative
arterial switch procedure may be considered as an alternative for the
management of these high risk ventriculo-arterial discordant single
ventricle patients with a systemic outlet obstruction.
In summary; pASO is a complex operation, with a long bypass run and
remarkable ischemic period but these patients are easier to manage
postoperatively than most of the other palliative procedures, since they
mostly have banded physiology because of the bulboventricular foramen
when coming out of the operating room. The post-operative banded
physiology with a harmonious systemic outflow tract simplifies their
early post-operative management and offer long-term benefits of systolic
and diastolic function preservation that make patients with single
ventricles good candidates for the Fontan procedure. We think that our
study will help to support an early aggressive approach to rule out
potential late complications and facilitate successful palliation of
these complicated subset of patients.
CONCLUSION
The ultimate palliation for infants with univentricular hearts,
transposition of the great arteries and systemic outflow tract
obstruction creates a safe passage through the neonatal period but also
prepare them for the long term. pASO provides a natural alignment
between the systemic outflow tract and the dominant ventricle and
maintains an unrestricted laminar systemic flow pattern to preserve
systolic or diastolic function for the future settings. The prevention
of further myocardial hypertrophy offers less tendency for further BVF
restriction. Thus, considerably easier medical management of pulmonary
banding physiology prevents the fluctuations in systemic and pulmonary
vascular resistance postoperatively. LeCompte maneuver in addition to
the advantages of pASO, by pulling the pulmonary arteries anteriorly,
excludes the probability of left pulmonary artery entrapment, which is a
possible complication of DKS procedure. Having a functioning pulmonary
valve in place also prevents the probable future diastolic dysfunction
which is possible with procedures involving shunts, resulting with
increase in ventricular volume load.
Limitations
This study is limited because of its retrospective pattern, but mostly
the patients were decided to go with pASO in the operating room, which
creates a selection bias. The follow-up is midterm for the time being,
and 1 patient lost f/u for the given reasons above. The long-term
results need to be reevaluated for future discussions.
Declaration of Conflicting Interests and Funding
The author(s)‘ declared no conflicts of interest and received no
financial support for the research and publication of this article.
REFERENCES
1. Webber SA, Leblanc JG, Keeton BR, et al. aralOthoraeic Surgery.
Published online 1995:515-520.
2. Rodefeld MD, Ruzmetov M, Schamberger MS, Girod DA, Turrentine MW,
Brown JW. Staged surgical repair of functional single ventricle in
infants with unobstructed pulmonary blood flow. Eur J
Cardio-thoracic Surg . 2005;27(6):949-955.
doi:10.1016/j.ejcts.2005.01.066
3. Freedom RM, Benson LN, Smallhorn JF, Williams WG, Trusler GA, Rowe
RD. Subaortic stenosis, the univentricular heart, and banding of the
pulmonary artery: an analysis of the courses of 43 patients with
univentricular heart palliated by pulmonary artery banding.Circulation . 1986;73(4):758-764. doi:10.1161/01.cir.73.4.758
4. Jahangiri M, Shinebourne EA, Ross DB, Anderson RH, Lincoln C.
Long-term results of relief of subaortic stenosis in univentricular
atrioventricular connection with discordant ventriculoarterial
connections. Ann Thorac Surg . 2001;71(3):907-910.
doi:10.1016/S0003-4975(00)02544-3
5. Jonas RA, Castaneda AR, Lang P. Single Ventricle (Single- or
Double-Inlet) Complicated by Subaortic Stenosis: Surgical Options in
Infancy. Ann Thorac Surg . 1985;39(4):361-366.
doi:10.1016/S0003-4975(10)62633-1
6. Fiore AC, Rodefeld M, ViJay P, et al. Subaortic obstruction in
univentricular heart: results using the double barrel Damus-Kaye Stansel
operation. Eur J Cardio-thoracic Surg . 2009;35(1):141-146.
doi:10.1016/j.ejcts.2008.09.037
7. Freedom RM, Williams WG, Fowler RS, Trusler GA, Rowe RD. Tricuspid
atresia, transposition of the great arteries, and banded pulmonary
artery. Repair by arterial switch, coronary artery reimplantation, and
right atrioventricular valved conduit. J Thorac Cardiovasc Surg .
1980;80(4):621-628.
8. Karl TR, Watterson KG, Sano S, Mee RBB. Operations for subaortic
stenosis in univentricular hearts. Ann Thorac Surg .
1991;52(3):420-428. doi:10.1016/0003-4975(91)90901-2
9. Lacour-Gayet F, Serraf A, Fermont L, et al. Early palliation of
univentricular hearts with subaortic stenosis and ventriculoarterial
discordance. The arterial switch option. J Thorac Cardiovasc
Surg . 1992;104(5):1238-1245.
10. Fraser CD. Management of Systemic Outlet Obstruction in Patients
Undergoing Single Ventricle Palliation. Semin Thorac Cardiovasc
Surg Pediatr Card Surg Annu . 2009;12(1):70-75.
doi:10.1053/j.pcsu.2009.01.006
11. Heinle JS, Carberry KE, McKenzie ED, Liou A, Katigbak PA, Fraser CD.
Outcomes after the palliative arterial switch operation in neonates with
single-ventricle anatomy. Ann Thorac Surg . 2013;95(1):212-219.
doi:10.1016/j.athoracsur.2012.09.028
12. Gil-Jaurena JM, Zabala J-I, Albert DC, Castillo R, González M, Miró
L. Palliative Arterial Switch as First-line Treatment Before the Fontan
Procedure in Patients With Single-ventricle Physiology and Subaortic
Stenosis. Rev Española Cardiol (English Ed . 2013;66(7):553-555.
doi:10.1016/j.rec.2013.01.020
13. Serraf A, Conte S, Lacour-Gayet F, et al. Systemic obstruction in
univentricular hearts: Surgical options for neonates. Ann Thorac
Surg . 1995;60(4):970-977. doi:10.1016/0003-4975(95)00520-U
14. Park WK, Baek JS, Kwon BS, et al. Revisitation of Double-Inlet Left
Ventricle or Tricuspid Atresia With Transposed Great Arteries. Ann
Thorac Surg . 2019;107(4):1212-1217.
doi:10.1016/j.athoracsur.2018.11.052
15. Kirklin JK, Blackstone EH, Kirklin JW, Pacifico AD, Bargeron LMJ.
The Fontan operation. Ventricular hypertrophy, age, and date of
operation as risk factors. J Thorac Cardiovasc Surg .
1986;92(6):1049-1064.
16. Hosein RBM, Clarke AJB, McGuirk SP, et al. Factors influencing early
and late outcome following the Fontan procedure in the current era. The
“Two Commandments”? Eur J Cardio-thoracic Surg .
2007;31(3):344-353. doi:10.1016/j.ejcts.2006.11.043
17. Anderson RH, Ho SY. The pathology of subaortic obstruction.Ann Thorac Surg . 1998;66(2):644-648.
doi:10.1016/S0003-4975(98)00576-1
18. Stansel H. How to do it. Ann Thorac Surg . 1975;19(5):565-567.
doi:10.1093/occmed/kqx180
19. Lamberti JJ, Mainwaring RD, Waldman JD, et al. The Damus-Fontan
Procedure. Published online 1991.
20. Lotto AA, Hosein R, Jones TJ, Barron DJ, Brawn WJ. Outcome of the
Norwood procedure in the setting of transposition of the great arteries
and functional single left ventricle. Eur J Cardio-thoracic Surg .
2009;35(1):149-155. doi:10.1016/j.ejcts.2008.09.016