The results of arterial switch surgery for transposition of the great arteries: the European Congenital Heart Surgeons Association (ECHSA) Congenital Database and Children’s City Clinical Hospital named after N.F. Filatov database

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OBJECTIVE

To highlight the results of arterial switch operation (ASO) reported in the European Congenital Heart Surgeons Association Congenital Database (ECHSA DB) and to compare them with own data obtained at the Children’s City Clinical Hospital named after N.F. Filatov.

MATERIAL AND METHODS

To assess the results of ASO as recorded in broad clinical practice, ECHSA DB was queried. We selected all records with primary diagnoses TGA-IVS, TGA-IVS-LVOTO, TGA-NOS (i.e., not otherwise specified), TGA-VSD, TGA-VSD-LVOTO and analyzed all ASO procedures including ASO with concomitant cardiac defect repair. We identified a total of 10.825 ASOs among a total of almost 350.000 procedures reported from 148 centers. At the Children’s City Clinical Hospital named after N.F. Filatov, a total of 210 ASO procedures have been performed between 2008 and 2021.

RESULTS. ECHSA DB:

There were 7.849 ASOs for TGA-IVS (72.5%), 2.789 ASOs with VSD repair for TGA-VSD (25.8%). Aortic arch obstruction was present in only 200 cases (2.5%) and associated with VSD in two thirds of cases. Overall in-hospital mortality was 5.8%. Notably, mortality declines through the last two decades (2001—2021) from 12 to 4.6%. There were 1.482 reoperations (13.7%) after prior primary ASO throughout the same time interval. Children’s City Clinical Hospital named after N.F. Filatov: there were 155 ASOs for TGA-IVS (73.8%) and 55 ASOs with VSD repairs for TGA-VSD (26.2%). Concomitant LVOT obstruction was present in 8 cases (3.9%), coarctation of the aorta — in 4 cases (2.0%). Overall in-hospital mortality was 5.2% (n=11). Regarding reoperations, one patient (0.5%) developed left pulmonary artery branch stenosis and underwent balloon dilatation.

CONCLUSION

ASO for TGA is associated with excellent results and gradually declining in-hospital mortality over the last twenty years documented in the ECHSA Congenital Database. Postoperative results after ASO achieved in the Children’s City Clinical Hospital named after N.F. Filatov are excellent and comparable with current ECHSA Database results in all subtypes of transposition. Furthermore, a remarkably lower need for delayed redo interventions was noted in our sample.

Keywords:

transposition of the great arteries

arterial switch operation

the European Congenital Heart Surgeons Association Congenital Database

Authors:

G.E. Sarris

Athens Heart Surgery Institute and Mitera Children’s Hospital

E. Protopapas

Mitera Children’s Hospital

O. Kornoukhov

Children’s City Clinical Hospital named after N.F. Filatov

V.N. Ilyin

Children’s City Clinical Hospital named after N.F. Filatov

Received:

27.05.2022

Accepted:

12.06.2022

List of references:

Marek J, Tomek V, Škovránek J, Povýšilová V, Šamánek M. Prenatal ultrasound screening of congenital heart disease in an unselected national population: A 21-year experience. Heart. 2011;97(2):124-130.
Moe TG, Bardo DME. Long-term Outcomes of the Arterial Switch Operation for D-Transposition of the Great Arteries. Prog Cardiovasc Dis. 2018;61(3-4):360-364. https://doi.org/10.1016/j.pcad.2018.08.007
Fricke TA, Konstantinov IE. Arterial Switch Operation: Operative Approach and Outcomes. Annals of Thoracic Surgery. 2019;107(1):302-310.
Sarris GE, Balmer C, Bonou P, et al. Clinical guidelines for the management of patients with transposition of the great arteries with intact ventricular septum: The Task Force on Transposition of the Great Arteries of the European Association for Cardio-Thoracic Surgery (EACTS) and the Assoc. Eur J Cardio-thoracic Surg. 2017;51(1):1-32.
Hutter PA, Kreb DL, Mantel SF, et al. Twenty-five years’ experience with the arterial switch operation. J Thorac Cardiovasc Surg. 2002;124(4):790-797.

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Introduction

Transposition of the great arteries (TGA), first described by Farrein 1814, is the most common cyanotic congenital heart defect and characterized by ventriculoarterial discordance in the context of atrioventricular concordance [1]. The left ventricle is connected to the pulmonary artery and the right ventricle is connected to the aorta. TGA is subclassified into two categories depending on whether the interventricular septum is intact (TGA with intact ventricular septum: TGA-IVS) or ventricular septal defect is present (TGA-VSD, the latter frequently referred as a complex TGA). Other associated anomalies may be present, such as coarctation of the aorta and aortic arch hypoplasia. The second category also includes cases with left ventricular outflow tract obstruction (LVOTO), management of which is not a focus of this paper. TGA accounts for about 5% of all congenital heart diseases with 60-70% of patients being male [2]. There is no known association with chromosomal abnormalities. Arterial switch operation (ASO), as it was described by Jatene in 1975, with additional Lecompte maneuver, is now considered the gold standard for the treatment of patients with TGA. ASO is a technically challenging procedure. Accordingly, many centers have experienced steep learning curves with high mortality in their early experience when they adopted the ASO approach in favor of the older and lower risk atrial switch procedures. Indeed, previous reports from the European Congenital Heart Surgeons Association Congenital Database containing information about more than 330.000 congenital operations from 148 centers from Europe and around the world, have demonstrated high mortality associated with ASO in participating centers and its decline over the last twenty years.

The purpose of this paper is to highlight the results of ASO achieved in the ECHSA Congenital Database and to compare these data with the results obtained at the Children’s City Clinical Hospital named after N.F. Filatov.

Methods

To assess the results of ASO as recorded in broad clinical practice, The European Congenital Heart Surgeons Association Congenital Database was queried (https://echsacongenitaldb.org). We selected all records with primary diagnosis: TGA-IVS, TGA-IVS-LVOTO, TGA-NOS (i.e., not otherwise specified), TGA-VSD, TGA-VSD-LVOTO, and analyzed all the following recorded procedures:

— ASO;

— ASO + VSD repair;

— ASO + VSD repair + aortic arch repair;

— ASO + aortic arch repair.

We identified a total of 10.825 ASOs among almost 350.000 procedures reported from 148 centers.

At the Children’s City Clinical Hospital named after N.F. Filatov, a total of 210 ASOs have been performed between 2008 and 2021, and their medical records have been reviewed and analyzed.

Results

1) ECHSA Congenital Database

Mean age of patients was 1.34 months (range 0—9.9). Most procedures were performed in neonates (87.1%) at the mean age of 9.3±5.7 days. A minority of procedures (11.6%) was performed in infancy, and only 142 operations were carried out in children (fig. 1). Mean weight was 3.6±1.9 kg (range 0.4—80). Mean cardiopulmonary bypass time was 174.7±68.0 min, and mean length of hospital-stay was 16.5±16.0 days.

Fig. 1. Distribution of ECHSA Congenital Database patients who underwent various ASO between 2008 and 2021.

There were 7.849 ASOs for TGA-IVS (72.5%) and 2.789 ASOs with VSD repair for TGA-VSD (25.8%). Aortic arch obstruction was present only in 200 cases (2.5%), and it was associated with VSD in two thirds of cases.

Overall in-hospital mortality was 5.8%. Mortality depended on surgery type: 5.0% after ASO for TGA-IVS, 8.4% after ASO with VSD repair and 9.5% after concomitant aortic arch repair (fig. 2).

Fig. 2. In-hospital mortality recorded in the ECHSA Congenital Database for various procedures between 2008 and 2021.

In addition, in-hospital mortality differs between age groups (fig. 3). Age of patients prior to surgery cannot be an independent risk factor because patients with complex TGA are usually operated on later, and we know that VSD increases mortality. Furthermore, late presentation is also a known risk factor [4].

Fig. 3. In-hospital mortality recorded in the ECHSA Congenital Database for ASO between 2008 depending on patient age.

Notably, mortality declines through successive years (fig. 4). Thus, in 2001 overall in-hospital mortality was almost 12% (13.3% for TGA-IVS and 7.1% for TGA-VSD) and declined to 4.6% in 2021 (2.8% for TGA-IVS and 8.2% for TGA-VSD).

Fig. 4. Overall in-hospital mortality recorded in the ECHSA Congenital Database for ASO between 2001 and 2021.

Regarding reoperations, it should be noted that the ECHSA congenital database does not include the follow-up data. Still, the database provides cross-sectional information about the number of reoperations which took place during the same time interval as the study period in patients with previous primary ASO. It is acknowledged that the available data do not permit calculation of the reoperation rate, since it is not recorded in the database if the initial repair (ASO) in patients whose reoperation is recorded has been included in our numbers (e.g., the initial repair may have been performed before 2001 or in a center which is not registered in the ECHSA congenital database). With the above caveats acknowledged, 1.482 reoperations after prior primary ASO were recorded during the same time interval (2001—2021), yielding a concurrent prevalence of redo ASO of 13.7%.

Of these reoperations, 1.012 (68.3%) were undertaken to treat post-ASO right ventricular outflow tract obstruction. Most of these procedures took place in childhood, and they involved main pulmonary and/or pulmonary branch repair with associated overall in-hospital mortality of 5.1%.

Reoperations to address left-sided lesions were recorded in 309 post-ASO patients, with associated overall in-hospital mortality of 6.2%. Late coronary complications were relatively rare, and only 161 patients had coronary artery surgery with overall in-hospital mortality of 22.8%.

2) Children’s City Clinical Hospital named after N.F. Filatov

Mean age of patients was 11 days (range 1—1.2). It is noted that 16.2% (n=34) of patients underwent two-stage ASO that affected the age range in the entire cohort. Nevertheless, most procedures were performed in neonates (n=165, 78.6%) with mean age 10±5.8 days. A minority of procedures (18.6%) was performed in infancy. Age-adjusted distribution of patients is depicted in fig. 5.

Fig. 5. Distribution of neonates, infants and children who underwent various ASO procedures between 2008 and 2021 at the Filatov Children’s Hospital.

The median weight of patients was 3.5 kg (range 2.3—12.6). Mean CPB time was 163±49.3 (range 80f709) min. The median length of hospital-stay was 13 days (range 8—65). Overall clinical characteristics and outcomes of ASO patients compared to those in the ECHSA congenital database are summarized in fig. 6.

Fig. 6. Overall clinical characteristics and outcomes of ASO patients at the ECHSA congenital database and Filatov Children’s Hospital.

There were 155 ASOs for TGA-IVS (73.8%) and 55 ASOs with VSD repair for TGA-VSD (26.2%). LVOT obstruction was present in 8 (3.9%) cases, concomitant coarctation of the aorta — in 4 (2.0%) cases. It is noted that 6 out of 8 patients with LVOT obstruction and 3 out of 4 ones with coarctation of the aorta also had VSD. Distributions of ASO patients according to diagnosis and type of procedure are shown in fig. 7. Overall in-hospital mortality was 5.2% (n=11). Of these, 7 patients had TGA-IVS (in-hospital mortality 4.9%), 3 ones — TGA-VSD (in-hospital mortality 5.5%) and 1 patient — TGA-LVOT obstruction (in-hospital mortality 12.5%). Comparison of overall and diagnosis-related in-hospital mortality rates after ASO is depicted in fig. 8.

Fig. 7. Distribution of ASO patients in the ECHSA congenital database and Filatov Children’s Hospital according to diagnosis/type of procedure.

Fig. 8. Overall and diagnosis-adjusted in-hospital mortality after ASO in the ECHSA congenital database and Filatov Children’s Hospital.

Although there was no clear trend for in-hospital mortality through years, no in-hospital mortality of TGA patients has been observed at the Children’s City Clinical Hospital named after N.F. Filatov since 2019. During this time interval, 56 patients (26.7% of study cohort) underwent ASO.

Unplanned reoperations after primary ASO were needed in 5 (2.5%) children. Two (1.0%) patients had coarctation of the aorta which developed de novo 2 months after ASO in both cases. Coarctation was successfully repaired through the left-sided lateral thoracotomy. Two patients (1.0%) developed compression of the left main bronchus and underwent aortopexy. One patient with TGA-VSD-LVOTO required implantation of a permanent pacemaker in 3 weeks after ASO.

There was one late death in 141 days after ASO caused by the left coronary artery lesion.

Regarding late re-interventions, one patient developed left pulmonary artery branch stenosis and underwent balloon dilatation.

Discussion

Arterial switch operation is considered as the gold standard for the treatment of various forms of transposition of the great arteries. In the current era, ASO has excellent early outcomes, while the majority of patients are growing into healthy adults [3]. Hutter et al. [5] stated that mortality rates were as high as 60% in early period in their center which gradual decrease to 3.9%. ASO had replaced atrial switch operation in most cases of TGA with better results achieved as the learning curve passed. Similar to the ECHSA congenital database, our data demonstrate that in-hospital mortality was significantly higher in 2000 and subsequently declined to the current levels by 2020—2021 (4% for TGA-IVS and 8% for TGA-VSD).

Over the same period, the ASO program at the Children’s City Clinical Hospital named after N.F. Filatov has achieved excellent results with mortality comparable to that in the ECHSA congenital database. Specifically, these results have not exhibited a learning curve, most likely because the ASO program was started in 2008 by a trained team. Accordingly, postoperative results in this hospital are favorably comparable with the most recent ECHSA database results.

Aortic arch obstruction and LVOTO associated with TGA is rare in the Moscow experience, as in the entire European dataset, with comparable mortality for concomitant repair.

Regarding the long-term outcomes, especially re-interventions, a very low incidence of late complications is noted in the Filatov Children’s Hospital with rare reoperations for RVOT obstruction (1/199, that is 0.5%). It is much less frequent compared to literature data. We ascribe this to the use of careful technique for accurate neo-pulmonary artery reconstruction using untreated trapezium-shaped autologous pericardium during aortic cross-clamping. Also, we have not seen neo-aortic root dilation and neo-aortic valve insufficiency. One patient from the Filatov Children’s Hospital cohort has demonstrated the coronary ischemic complication resulting in late death. Overall long-term results were excellent, but longer detailed follow-up will be necessary to evaluate the incidence and impact of rarer complications of ASO, such as coronary ischemia or neoaortic valve dysfunction.

Our study has several limitations. The retrospective analysis of data from 148 ECHSA Congenital Database centers includes variability in individual center practices and volume, surgical techniques and perioperative management and thus reflects the average of such practices. Furthermore, the ECHSA congenital database, being a surgical procedure registry, does not include long-term follow-up data for direct comparison with data from the Filatov Children’s Hospital on the long-term outcomes.

Conclusion

The ASO for TGA is associated with excellent early and late results and gradually declining in-hospital mortality over the last twenty years documented in the ECHSA congenital database. Surgical results of ASO achieved in the Filatov Children’s City Hospital of Moscow Healthcare Department are excellent with no learning curve effect on in-hospital mortality. These data are comparable with the current ECHSA database results in all subtypes of TGA. Furthermore, a remarkably low need for late re-operation is noted in the Filatov Children’s City Hospital.