Repair of complex transposition of great arteries: What is the best technique to avoid outflow tract obstructions?

OBJECTIVES: This study aimed to evaluate the short-/mid-term outcome of patients with complex dextro (d)-/levo (l)-transposition of the great arteries (TGA), ventricular septal defect and left ventricular outflow tract obstructions. METHODS: A single-centre, retrospective review of all complex dextro-TGA (n = 85) and levo-TGA (n = 22) patients undergoing different surgeries [Arterial switch operation + left ventricular outflow tract obstruction-resection (ASO-R), half-turned truncal switch/Mair (HTTS), Nikaidoh and Rastelli] between May 1990 and September 2022 was performed. Groups were analysed using Kruskal-Wallis test with post hoc pairwise comparison and Kaplan-Meier time-to-event models. RESULTS: A total of 107 patients [ASO-R (n = 20), HTTS (n = 23), Nikaidoh (n = 21), Rastelli (n = 43)] were included, with a median age of 1.0 year (0.5-2.5) and surgical repair median follow-up was 3.8 years (0.3-10.5). Groups did not differ in respect to early postoperative complications/early mortality. Five-year overall survival curves were comparable: ASO-R 78.9% (53.2-91.5), HTTS 75.3% (46.8-89.9), Nikaidoh 85% (60.4-94.9) and Rastelli 83.9% (67.5-92.5), P = 0.9. Highest rates of right ventricular outflow tract (RVOT) reinterventions [33.3% and 32.6% (P = 0.04)] and reoperations [28.6% and 32.6% (P = 0.02)] occurred after Nikaidoh and Rastelli procedures. However, overall freedom from RVOT reinterventions and RVOT reoperations at 5 years did not differ statistically significantly between the groups (ASO-R, HTTS, Nikaidoh and Rastelli): 94.4% (66.6-99.2), 69.1% (25.4-90.5), 67.8% (34-86.9), 64.4% (44.6-78.7), P = 0.2, and 90.0% (65.6-97.4), 91% (50.8-98.7), 65.3% (32.0-85.3) and 67.0% (47.4-80.6), P = 0.3. CONCLUSIONS: Surgical repair of complex dextro-/levo-TGA can be performed with satisfying early/mid-term survival. RVOT reinterventions/reoperations were frequent, with highest rates after Nikaidoh and Rastelli procedures. Left ventricular outflow tract obstruction reoperations were rare with zero events after Nikaidoh and HTTS procedures.

The impact of unilateral pulmonary artery stenosis on right ventricular to pulmonary arterial coupling in patients with transposition of the great arteries.

BACKGROUND: Unilateral pulmonary artery (PA) stenosis is common in the transposition of the great arteries (TGA) after arterial switch operation (ASO) but the effects on the right ventricle (RV) remain unclear. AIMS: To assess the effects of unilateral PA stenosis on RV afterload and function in pediatric patients with TGA-ASO. METHODS: In this retrospective study, eight TGA patients with unilateral PA stenosis underwent heart catheterization and cardiac magnetic resonance (CMR) imaging. RV pressures, RV afterload (arterial elastance [Ea]), PA compliance, RV contractility (end-systolic elastance [Ees]), RV-to-PA (RV-PA) coupling (Ees/Ea), and RV diastolic stiffness (end-diastolic elastance [Eed]) were analyzed and compared to normal values from the literature. RESULTS: In all TGA patients (mean age 12 ± 3 years), RV afterload (Ea) and RV pressures were increased whereas PA compliance was reduced. RV contractility (Ees) was decreased resulting in RV-PA uncoupling. RV diastolic stiffness (Eed) was increased. CMR-derived RV volumes, mass, and ejection fraction were preserved. CONCLUSION: Unilateral PA stenosis results in an increased RV afterload in TGA patients after ASO. RV remodeling and function remain within normal limits when analyzed by CMR but RV pressure-volume loop analysis shows impaired RV diastolic stiffness and RV contractility leading to RV-PA uncoupling.

External Validation of a Risk Score Model for Predicting Major Clinical Events in Adults After Atrial Switch.

BACKGROUND: A risk model has been proposed to provide a patient individualized estimation of risk for major clinical events (heart failure events, ventricular arrhythmia, all-cause mortality) in patients with transposition of the great arteries and atrial switch surgery. We aimed to externally validate the model. METHODS AND RESULTS: A retrospective, multicentric, longitudinal cohort of 417 patients with transposition of the great arteries (median age, 24 years at baseline [interquartile range, 18-30]; 63% men) independent of the model development and internal validation cohort was studied. The performance of the prediction model in predicting risk at 5 years was assessed, and additional predictors of major clinical events were evaluated separately in our cohort. Twenty-five patients (5.9%) met the major clinical events end point within 5 years. Model validation showed good discrimination between high and low 5-year risk patients (Harrell C index of 0.73 [95% CI, 0.65-0.81]) but tended to overestimate this risk (calibration slope of 0.20 [95% CI, 0.03-0.36]). In our population, the strongest independent predictors of major clinical events were a history of heart failure and at least mild impairment of the subpulmonary left ventricle function. CONCLUSIONS: We reported the first external validation of a major clinical events risk model in a large cohort of adults with transposition of the great arteries. The model allows for distinguishing patients at low risk from those at intermediate to high risk. Previous episode of heart failure and subpulmonary left ventricle dysfunction appear to be key markers in the prognosis of patients. Further optimizing risk models are needed to individualize risk predictions in patients with transposition of the great arteries.

Perfusion techniques for an 800 g premature neonate undergoing Arterial Switch Procedure for Transposition of the Great Arteries☠.

Early cardiac surgery in neonates and infants with congenital heart disease has been performed since the middle to late years of the twentieth century. To date, there are very few reports of successful congenital heart surgery using cardiopulmonary bypass (CPB) in premature babies less than 1000 g with serious congenital heart disease. Limited information is available in the literature describing perfusion techniques for this extremely fragile patient population. Miniaturization of the CPB circuit contributes to multiple factors that affect this population significantly. These factors include the reduction of patient-to-circuit ratios, volume of distribution of pharmacological agents, management of pressure gradients within the CPB system, and increased tactile control by the attending perfusionist. Careful management of the physiological environment of the patient is of utmost importance and can mitigate risks during CPB, including volume shifts into the interstitial space, electrolyte, and acid-base imbalance, and intracranial hemorrhage. We report perfusion techniques successfully utilized during the surgical repair of transposition of the great arteries for an 800 g, 28-week-old neonate. CPB techniques for the smallest and youngest patients may be executed safely when proper physical, chemical, and perfusion process adjustments are made and managed meticulously.

Increased aortic pressures and pulsatile afterload components promote concentric left ventricular remodeling in adults with transposition of the great arteries and arterial switch operation.

BACKGROUND: Functional abnormalities of the ascending aorta (AA) have been mainly reported in young patients who underwent arterial switch operation (ASO) for transposition of the great arteries (TGA). OBJECTIVES: To compare systolic, diastolic brachial and central blood pressures (bSBP, bDBP, cSBP, cDBP), aortic biomechanical parameters, and left ventricular (LV) afterload criteria in adult ASO patients with healthy controls and to assess their relationships with LV remodeling and aortic size. MATERIALS AND METHODS: Forty-one prospectively enrolled patients (16.8 to 35.8 years) and 41 age- and sex-matched healthy volunteers underwent cardiac MRI to assess LV remodeling with simultaneous brachial BP estimation. After MRI, carotid-femoral tonometry was performed to measure pulse wave velocity (cfPWV), cSBP and cDBP for further calculation of pulse pressure (cPP), AA distensibility (AAD), and AA and LV elastance (AAE, LVE). RESULTS: bSBP, bDBP, cSBP,cDBP and cPP were all significantly higher in ASO group than in controls: cSBP (116.5 ± 13.8 vs 106.1 ± 12.0, p < 0.001), cDBP (72.5 ± 6.9 vs 67.1 ± 9.4, p = 0.002), cPP (44.0 ± 12.1 vs 39.1 ± 8.9, p = 0.003) and not related to aortic size. AAD were decreased in ASO patients vs controls (4.70 ± 2.72 vs 6.69 ± 2.16, p < 0.001). LV mass was correlated with bSBP, cSBP, cPP (ρ = 0.48; p < 0.001), while concentric LV remodeling was correlated with AAE (ρ = 0.60, p < 0.001) and LVE (ρ = 0.32, p = 0.04), but not with distensibility. CONCLUSION: Even without reaching arterial hypertension, aortic sBP and PP are increased in the adult TGA population after ASO, altering the pulsatile components of afterload and contributing to LV concentric remodeling.

Perioperative Factors and Radiographic Severity Scores for Predicting the Duration of Mechanical Ventilation After Arterial Switch Surgery.

OBJECTIVES: Cardiac surgery on cardiopulmonary bypass (CPB) during the neonatal period can cause perioperative organ injuries. The primary aim of this study was to determine the incidence and risk factors associated with postoperative mechanical ventilation duration and acute lung injury after the arterial switch operation (ASO). The secondary aim was to examine the utility of the Brixia score for characterizing postoperative acute lung injury (ALI). DESIGN: A retrospective study. SETTING: A single-center university hospital. PARTICIPANTS: A total of 93 neonates with transposition of great arteries with intact ventricular septum (dTGA IVS) underwent ASO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: From January 2015 to December 2022, 93 neonates with dTGA IVS were included in the study. The cohort had a median age of 4.0 (3.0-5.0) days and a mean weight of 3.3 ± 0.5 kg. About 63% of patients had ≥48 hours of postoperative mechanical ventilation after ASO. Risk factors included prematurity, post-CPB transfusion of salvaged red cells, platelets and cryoprecipitate, and postoperative fluid balance by univariate analysis. The larger transfused platelet volume was associated with the risk of ALI by multivariate analysis. The median baseline Brixia scores were 11.0 (9.0-12.0) and increased significantly in the postoperative day 1 in patients who developed moderate ALI 24 hours after admission to the intensive care unit (15.0 [13.0-16.0] v 12.0 [10.0-14.0], p = 0.046). CONCLUSIONS: Arterial switch operation results in a high incidence of ≥48-hour postoperative mechanical ventilation. Blood component transfusion is a potentially modifiable risk factor. The Brixia scores also may be used to characterize postoperative acute lung injury.

Left atrial strain in adults after the arterial switch operation for transposition of the great arteries.

BACKGROUND: No study has focused on left atrial (LA) function assessed by echocardiography in adult patients with simple D-TGA after arterial switch operation (ASO). We aimed to describe LA strain parameters in these patients. METHODS: A prospective cohort study including 42 adult patients with simple D-TGA after ASO and 33 aged-matched controls. Phasic LA and LV global longitudinal strain (GLS) were obtained by transthoracic 2D-speckle tracking echocardiography (STE). Volumetric and functional analysis of LA and LV were also evaluated by 2D and 3D analysis. A multivariable model was performed to investigate the variables that best differentiate patients with D-TGA from healthy controls. RESULTS: LA strain parameters in D-TGA patients were within the normal range described for healthy subjects. However, the three LA strain parameters (Reservoir, Conduit, and Contraction) were lower in patients (LASr: 31.13 ± 7.67 vs. 49.71 ± 8.38; LAS cd: -22.91 ± 5.69 vs. -34.55 ± 6.54; LASct: -8.14 ± 4.93 vs. -15.15 ± 6.07, p < .001 for all three comparisons). LA volumes were similar between patients and controls. LV-GLS remained significantly lower in the D-TGA group than in controls (-17.29 ± 2.68 vs. -21.98 ± 1.84, p < .001). D-TGA patients had evidence of worse LV ejection fraction measured by the Teichholz method (63.38 ± 8.23 vs. 69.28 ± 5.92, p = .001) and 3D analysis (57.97% ± 4.16 vs. 60.67 ± 3.39, p = .011) and diastolic dysfunction as compared to healthy controls. LV-GLS and conduit LAS were the variables best differentiating patients with D-TGA from healthy controls. CONCLUSIONS: LA strain is impaired in young adults with simple D-TGA late after the ASO, probably in agreement with some degree of LV dysfunction previously described.

Prevalence of Branch Pulmonary Artery Reintervention Following the Arterial Switch Operation.

BACKGROUND: The arterial switch operation (ASO) is the preferred surgical procedure used to correct dextro-transposition of the great arteries. A known complication of the ASO is branch pulmonary arteries (PAs) stenosis, which may require reintervention. Our goal is to determine the frequency of reintervention after the ASO and any factors associated with reintervention. METHODS: This was a single center, retrospective study of infants who underwent the ASO from June 6, 2011 to February 21, 2021. The primary outcome was the prevalence of reintervention on the PAs following the ASO. RESULTS: Sixty-eight infants were analyzed; 9 (13%) patients had 10 reinterventions. The mean age at time of the ASO was 6.52 ± 6.63 days; weight was 3.34 ± 0.57 kg. Those with a reintervention had a longer bypass time (P = .047). Mean age at reintervention was 0.80 ± 0.72 years; mean time from the ASO to reintervention was 0.799 ± 0.717 years. Six surgical procedures, two stent placements, and four balloon angioplasties were performed on a total of 13 branch PAs. There was no increased risk for reintervention on the right versus left PA. After reintervention, there was an improvement in the minimal PA diameter and echo gradient. There were no adverse events or mortality related to the reintervention. Mean follow-up was 6.17 ± 2.94 years. CONCLUSION: The prevalence of branch PA reintervention following the ASO in our cohort was 13%. There is an association between longer cardiopulmonary bypass time and reintervention. After reintervention, there was an increase in PA diameter and a decrease in echo gradient.

Outcomes of neo-aortic valve and root surgery late after arterial switch operation.

BACKGROUND: Neo-aortic root dilatation and valve regurgitation are emerging problems late after arterial switch operation (ASO). We sought to evaluate the prevalence and outcomes of neo-aortic root or valve reoperation after ASO. METHODS: All patients with biventricular circulation who underwent an ASO between 1983 and 2015 were included at a single institution. RESULTS: In our cohort of 782 late ASO survivors, the median duration of follow-up was 18.1 years (interquartile range [IQR], 11.3-25.6 years). During follow-up, 47 patients (6.0%) underwent 60 reoperations on the neo-aortic valve/root. The first neo-aortic valve/root reoperation occurred at a median of 15.2 years (IQR, 7.8-18.4 years) after ASO. Operations included mechanical Bentall (31.9%; n = 15), aortic valve repair (25.5%; n = 12), mechanical aortic valve replacement (AVR) (21.3%; n = 10), valve-sparing root replacement (19.1%; n = 9), and the Ross procedure (2.1%; n = 1). There was 1 late death (2.1%). Multivariable predictors of neo-aortic valve/root reoperation were bicuspid valve (hazard ratio [HR], 4.8; 95% confidence interval [CI], 2.1-10.7; P < .001), Taussig-Bing anomaly (HR, 3.0; 95% CI, 1.2-7.4; P < .02), previous pulmonary artery band (HR, 2.8; 95% CI, 1.2-6.3; P < .01) and left ventricular outflow tract obstruction before ASO (HR, 2.4; 95% CI, 1.0-5.8; P < .04). Freedom from neo-aortic valve or root reoperation was 98.0% (95% CI, 96.7%-98.8%) at 10 years, 93.3% (95% CI, 90.8%-95.2%) at 20 years, and 88.5% (95% CI, 84.1%-91.8%) at 30 years after ASO. Among the 47 patients who underwent neo-aortic reoperation, freedom from AVR was 82.3% (95% CI, 67.7%-90.7%) at 10 years, 58.0% (95% CI, 41.8%-71.2%) at 20 years, and 43.2% (95% CI, 27.0%-58.3%) at 25 years after ASO. CONCLUSIONS: The need for neo-aortic valve or root reoperation surpasses 10% by 30 years post-ASO. Evolving understanding of the mechanisms of neo-aortic valve insufficiency and techniques of neo-aortic valve repair may decrease the need for AVR.

The Arterial Switch Operation in the Developing World: Risk Factors and Current Outcomes.

BACKGROUND: Published data on the outcomes of the arterial switch operation in the developing world are limited. We sought to identify the midterm outcomes of and risk factors for mortality and morbidity in patients undergoing the arterial switch operation at a high-volume center in Vietnam. METHODS: A retrospective review was conducted of 608 patients who underwent an arterial switch operation for the treatment of transposition of the great arteries (TGA; n = 509) or double-outlet right ventricle TGA (DORV-TGA; n = 99) at a single center from 2010 to 2021. RESULTS: Overall early mortality was 5.9%, and late mortality was 1%. Multivariate Cox regression showed weight at operation of <3 kg (P < .001), prolonged aortic cross-clamp time (P < .001), and need for secondary aortic cross-clamp (P = .011) as risk factors for overall mortality. The actuarial 10-year survival rate was 93%. The overall cardiac reoperation rate was significantly higher in patients with DORV-TGA (hazard ratio [HR], 16.43; 95% CI, 4.70-57.43; P < .001). The rate of freedom from cardiac reoperation at 10 years was 94%. Risk factors for outflow tract reoperation were patients with DORV-TGA (HR, 23.28; 95% CI, 2.86-189.66; P = .003), single coronary artery (HR, 4.1; 95% CI, 1.16-14.46; P = .028), and mild aortic valve regurgitation observed in 3.7% of patients. CONCLUSIONS: The outcomes of the arterial switch operation in a low- and middle-income country were satisfactory. Nevertheless, the complexity of the procedure and lower weight of patients are still challenges. Patients with DORV-TGA and single coronary artery need to be closely followed up.

Biomarkers in transposition of the great arteries after arterial switch operation: A pilot trial with deep phenotyping.

INTRODUCTION: Transposition of the great arteries (TGA) is a cyanotic congenital heart defect for which the arterial switch operation (ASO) is the preferred surgical repair. This study wanted to investigate whether a panel of biomarkers could identify morphologic as well as hemodynamic changes obtained by cardiac magnetic resonance (CMR). METHODS: Forty-four adult patients were included. Blood samples were collected to measure a broad range of biomarkers (galectin-3, ST2, GDF-15, PINP, ICTP, PIIINP, IGF-1, NT-proBNP, and hs-Tn). CMR was performed at rest and during exercise to assess cardiac function and morphology. Explorative statistics were performed between biomarker levels and CMR findings. RESULTS: All patients were asymptomatic. While galectin-3, GDF-15, and NT-proBNP levels were within normal ranges, increased ST2, PINP, PIIINP, and ICTP levels were found in 20.5%, 34.1%, 45.5%, and 27.3% of patients, respectively. Moreover, 3 and 2 patients, respectively, showed elevated IGF-1 and hs-Tn levels. Although the ejection fraction of both ventricles was within normal limits, impaired cardiac reserve was found in 20 and 25% of patients for left and right ventricle, respectively. CMR revealed no evidence of diffuse interstitial fibrosis, while 4 patients showed focal ischemic scarring. However, no significant associations between serum biomarkers and CMR data could be detected. CONCLUSION: The results suggest that in asymptomatic ASO-repaired TGA patients serum level biomarkers are elevated and that this increase is not associated with morphological changes nor with a decreased cardiac reserve. Further study with larger sample sizes is required to draw conclusions with greater confidence.

Outcomes of the Arterial Switch Operation in Patients With Dextrocardia.

BACKGROUND: Patients with dextrocardia and d-transposition of the great arteries (d-TGA) present a technical challenge when performing the arterial switch operation (ASO). We sought to determine the long-term outcomes of this rare presentation. METHODS: All patients who underwent the ASO with d-TGA and dextrocardia were identified from the hospital database. RESULTS: There were four patients with dextrocardia (4 of 844, 0.5%) patients; two patients had situs solitus and two patients had situs inversus. Three patients had a ventricular septal defect. Left ventricular outflow tract obstruction was present in one patient and one patient had a hypoplastic arch with severe coarctation of aorta. Anomalous coronary anatomy occurred in two patients. There was one early mortality and the cause of death was sepsis. One patient required late reoperation for severe neo-pulmonary valve regurgitation at 23 years after the ASO. At last follow-up, all three surviving patients were in New York Heart Association Class I. CONCLUSIONS: Patients with d-TGA and dextrocardia who undergo the ASO are extremely rare and require challenging operative management.

Acute superficial and deep necrosis of lower limb following femoral arterial cannulation in a neonate undergoing arterial switch operation for transposition of great arteries.

Arterial lines are routinely used for hemodynamic monitoring and blood sampling in the operating room and in cardiac surgery intensive care unit. The complications related to arterial line insertion are very low; the knowledge of the relevant artery anatomy, skills and the experience of the operator and selection of a right size cannula plays a vital role in reducing morbidity related to arterial line insertion. We describe extensive superficial and deep necrosis of lower limb following arterial cannula insertion in a preterm neonate undergoing arterial switch procedure and discuss measures to prevent such a complication.

Role of transesophageal echocardiography in early detection of myocardial ischemia before electrocardiography changes post arterial switch operation.

Myocardial ischemia after arterial switch operation is most commonly associated with imperfect translocation of coronary arteries to the neoaorta. Early post-operative myocardial ischemia is the main cause of morbidity and mortality in these patients. We present a rare case of intra-operative myocardial ischemia after ASO, detected with transesophageal echocardiography before electrocardiography changes.