Hemodynamic simulation of complete transposition of the great arteries for optimal treatment strategies based on its circulatory physiology.

Our study aimed to elucidate the role of different shunts and provide novel insights into optimal treatment approaches for complete transposition of the great arteries (TGA), which is characterized by unique and complicated circulatory dynamics. We constructed a computational cardiovascular TGA model and manipulated cardiovascular parameters, such as atrial septal defect (ASD) and patent ductus arteriosus (PDA) sizes, to quantify their effects on oxygenation and hemodynamics. In addition, ASD flow patterns were investigated as innovative indications for balloon atrial septostomy (BAS). Our model of TGA with an intact ventricular septum (TGA-IVS) showed that a large ASD can achieve sufficient mixing for survival without PDA, and the presence of PDA is detrimental to oxygen delivery. A treatment strategy for TGA-IVS that enlarges the ASD as much as possible by BAS and PDA closure would be desirable. In TGA with a ventricular septal defect (TGA-VSD), the VSD allows for higher oxygenation and reduces the detrimental effects of PDA on systemic circulation. In TGA-VSD, both strategies of enlarging the ASD by BAS with a closed PDA and adjusting the PDA in response to pulmonary vascular resistance (PVR) reduction without BAS may be effective. The simulated ASD flow patterns showed that the sharp peak left-to-right flow pattern in systole (σ-wave) reflected the hemodynamically significant ASD size, independent of PDA, VSD, and PVR. The ASD flow pattern visualized by Doppler echocardiography provides clinical insights into the significance of an ASD and indications for BAS, which are not readily apparent through morphological assessment.NEW & NOTEWORTHY Complete transposition of the great arteries (TGA) represents complex and unique circulation that is dependent on blood mixing through multiple interacting shunts. Consequently, the role of each shunt and the treatment strategy remain unclear. We developed a mathematical model of TGA circulation, revealing the significant influence of atrial septal defect (ASD) on oxygenation and hemodynamics. The blood flow pattern through the ASD reflects its hemodynamic impact and helps determine treatment strategies.

Transcatheter pulmonary valve replacement after arterial switch operation.

BACKGROUND: Patients with d-transposition of the great arteries (d-TGA) who have undergone an arterial switch operation (ASO) can develop right ventricular outflow tract (RVOT) dysfunction with pulmonary regurgitation (PR) or stenosis. In these patients, treatment may include transcatheter pulmonary valve replacement (TPVR). Coronary compression is a contraindication occurring in 5% of typical TPVR cases. After ASO, there are various anatomical considerations that can confound TPVR, including potential coronary artery compression. Our goal is to understand feasibility of TPVR in patients following ASO. METHODS: This was a retrospective multicenter cohort study of patients with RVOT dysfunction after ASO who underwent cardiac catheterization with intention to perform TPVR from 2008 to 2020. RESULTS: Across nine centers, 33 patients met inclusion criteria. TPVR was successful in 22 patients (66%), 19 receiving a Melody valve and 3 a SAPIEN valve. RVOT stenosis in isolation or with PR dictated need for TPVR in nearly all patients. One serious adverse event occurred with valve embolization. After TPVR, the RVOT peak gradient decreased from 43 to 9 mm Hg (p < 0.001); PR was trivial/none in all but one patient, in whom it was mild. Coronary compression prohibiting TPVR occurred in eight patients (24%) and two patients (6%) had severe aortic regurgitation from aortic root deformation precluding TPVR. Seven patients underwent RVOT reintervention with a median of 5.3 years post-TPVR. CONCLUSIONS: TPVR in patients with d-TGA after ASO is feasible, but in this cohort, coronary compression or aortic root distortion precluded TPVR in one-third of patients. The rate of RVOT reintervention after TPVR was higher in this cohort of ASO patients that in prior studies.

Balloon atrial septostomy for transposition of the great arteries: Safety and experience with the Z-5 balloon catheter.

BACKGROUND: Balloon atrial septostomy (BAS) is an emergent and essential cardiac intervention to enhance intercirculatory mixing at atrial level in deoxygenated patients diagnosed with transposition of the great arteries (TGA) and restrictive foramen ovale. The recent recall of several BAS catheters and the changes in the European legal framework for medical devices (MDR 2017/745), has led to an overall scarcity of BAS catheters and raised questions about the use, safety, and experience of the remaining NuMED Z-5 BAS catheter. AIMS: To evaluate and describe the practice and safety of the Z-5 BAS catheter, and to compare it to the performance of other BAS catheters. METHODS: A retrospective single-center cohort encompassing all BAS procedures performed with the Z-5 BAS catheter in TGA patients between 1999 and 2022. RESULTS: A total of 182 BAS procedures were performed in 179 TGA-newborns at Day 1 (IQR 0-5) days after birth, with median weight of 3.4 (IQR 1.2-5.7) kg. The need for BAS was urgent in 90% of patients. The percentage of BAS procedures performed at bedside increased over time from 9.8% (before 2010) to 67% (2017-2022). Major complication rate was 2.2%, consisting of cerebral infarction (1.6%) and hypovolemic shock (0.5%). The rate of minor complications was 9.3%, including temporary periprocedural AV-block (3.8%), femoral vein thrombosis (2.7%), transient intracardiac thrombus (0.5%), and atrial flutter (2.2%). BAS procedures performed at bedside and in the cardiac catheterization laboratory had similar complication rates. CONCLUSIONS: BAS using the Z-5 BAS catheter is both feasible and safe at bedside and at the cardiac catheterization laboratory with minimal major complications.

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.

Longitudinal changes in systemic right ventricular remodeling in adult patients with transposition of the great vessels as assessed by cardiovascular magnetic resonance imaging.

BACKGROUND: Systemic right ventricular (sRV) physiology occurs in patients with congenitally corrected transposition of the great arteries (ccTGA) and D-TGA post atrial switch repair, and the natural history is of progressive sRV dysfunction. No study has assessed longitudinal changes in sRV remodeling by serial CMR. METHODS: Patients evaluated at two adult congenital heart disease centers and who underwent ≥2 CMR exams were studied. Indexed sRV end-diastolic volume (sRVEDVi), end-systolic volume (sRVESVi), and ejection fraction (sRVEF) were determined by a core laboratory. Concurrent echocardiograms were assessed for degree of systemic TR (sTR). Tricuspid valve events were defined as ≥moderate sTR, or interval tricuspid replacement (TVR). Generally, the earliest and most recent studies were compared. A subset of patients were followed with ≥moderate sTR, and then subsequently underwent interval TVR. For these patients, two study time-intervals were defined to analyze the impact of each event independently. RESULTS: 67 patients were studied (33±11 years, 47% male, 33% ccTGA), with 72 total time intervals studied (median interval 9.0 years [IQR 4.6-13.3]). There was a small increase in sRVEDVi over time (ΔsRVEDVi 5.5±15.8ml/m2, p<0.001), but mean change in sRVEF was not significant (ΔsRVEF 0.1±6.9%, p=0.86); notably, confidence intervals were wide for both. ccTGA patients had a trend towards greater decrement in sRVEF (ΔsRVEF -1.7±6.8 vs 1.3±6.7%, p=0.06). For each 25ml/m2 increase in baseline sRVEDVi, there was a 1.8% decrease in sRVEF (95% CI -3.2% to -0.5%, p=0.01). Patients without significant sTR had lesser deterioration in sRVEF compared to those with ≥moderate sTR or with interval TR intervention (ΔsRVEF 1.8±6.9% vs -2.1±6.6% and -2.6±4.5, p<0.05). Interval sRV conduction delay was associated with a trend towards greater decrements in sRVEF (ΔsRVEF -3.9±6.3 vs. 0.9±6.8%, p=0.07). Overall, underlying congenital anatomy, baseline sRVEDVi, advanced sTR or interval TVR, and sRV conduction delay explained only 16% of the variability in ΔsRVEF over time. CONCLUSIONS: Longitudinal changes in sRV remodeling were small, with great heterogeneity. Apparent risk factors in our study, namely underlying congenital anatomy, baseline sRVEDVi, TR events, and sRV conduction disease accounted for only 16% of the variability seen in the longitudinal change of sRVEF.

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.

A rare combination of correct transposition of the great arteries and isolated levocardia: Imaging characterization.

Congenitally correct transposition of the great arteries (cc-TGA) is an extremely rare congenital cardiac malposition. It can be detected antenatally by echocardiography. This case report describes a 58-year-old female patient who presented with tachycardia. The combination of cc-TGA and isolated levocardia is incidentally diagnosed by transthoracic echocardiography and cardiac magnetic resonance imaging.

Review of speckle tracking analysis to measure the size, shape, and contractility of the fetal heart in fetuses with congenital heart defects.

Evaluation of the fetal heart involves two approaches. The first describes a screening protocol in which the heart is imaged in transverse planes that includes the four-chamber view (4CV), left and right outflow tracts, and the 3-vessel-tracheal view. The second approach is a fetal echocardiogram that requires additional cardiac images as well as evaluating ventricular function using diagnostic tools such as M-mode and pulsed Doppler ultrasound. Speckle tracking analysis of the ventricular and atrial endocardium of the fetal heart has focused primarily on computing longitudinal global strain. However, the technology enabling this measurement to occur has recently been adapted to enable the clinician to obtain numerous additional measurements of the size, shape, and contractility of the ventricles and atrial chambers. By using the increased number of measurements derived from speckle tracking analysis, we have reported the ability to screen for tetralogy of Fallot, D-transposition of the great arteries (D-TGA), and coarctation of the aorta by only imaging the 4CV. In addition, we have found that measurements derived from speckle tracking analysis of the ventricular and atrial chambers can be used to compute the risk for emergent neonatal balloon atrial septostomy in fetuses with D-TGA. The purpose of this review is to consolidate our experience in one source to provide perspective on the benefits of speckle tracking analysis to measure the size, shape, and contractility of the ventricles and atria imaged in the 4CV in fetuses with congenital heart defects.

Complete Transposition of the Great Arteries: 5-Year Experience From a Single Center.

Complete transposition of the great arteries (TGA) is the most common cause of cyanosis in the first week of life. Prenatal diagnosis helps with counseling, planning delivery, and postnatal management for resource-rich health services. In a resource-limited setting, postnatal diagnosis is the norm. This work examines cases of complete TGA in one center in Cambodia without prenatal testing. Twenty-four cases were studied over 5 years. Complex TGA was frequently seen. The majority had normal coronary anatomy and arterial switch operation (ASO) was performed in most cases with a favorable outcome.

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.

Impact of Persistent Pulmonary Hypertension of the Newborn in Neonates with Dextro-transposition of the Great Arteries.

OBJECTIVES: This study aimed to assess the impact of persistent pulmonary hypertension of the newborn (PPHN) on perioperative morbidity and mortality in patients with dextro-transposition of the great arteries. Secondarily, we evaluated the association between postoperative outcomes and intraoperative variables including the duration of cardiopulmonary bypass, cerebral oxygen desaturation, and hypotension. DESIGN: Retrospective observational study. SETTING: Beatrix Children's Hospital, University Medical Center Groningen, Groningen, the Netherlands, over a 14-year period from January 2005 to December 2018. PARTICIPANTS: The study included 99 consecutive patients with simple dextro-transposition of the great arteries with or without a ventricular septal defect. INTERVENTIONS: All patients received preoperative management including intravenous prostaglandin E1 and, when necessary, a balloon atrial septostomy. Patients were then scheduled for an arterial switch operation. MEASUREMENTS AND MAIN RESULTS: Patients were divided into a PPHN and a non-PPHN group. The outcomes assessed included mortality (overall, preoperative, 30-day postoperative and late mortality) and postoperative morbidity (length of ventilatory support, intensive care unit and hospital stay, delayed sternal closure and resternotomy). PPHN was present in 31% of patients. Overall mortality was 8.1%, with no difference between PPHN and non-PPHN patients (9.7 v 7.4%, p = 0.70). PPHN had no effect on morbidity outcomes. A lower weight at birth was associated with preoperative mortality. Duration of cardiopulmonary bypass and intraoperative hypotension were associated with longer intensive care unit stay. Intraoperative hypotension and cerebral oxygen desaturation had no significant impact on mortality. CONCLUSIONS: PPHN did not significantly affect perioperative morbidity and mortality in d-TGA patients, suggesting a more favorable prognosis than previously reported.

Molecular Pathways and Animal Models of d-Transposition of the Great Arteries.

During normal cardiovascular development, the outflow tract becomes septated and rotates so that the separate aorta and pulmonary trunk are correctly aligned with the left and right ventricles, respectively. However, when this process goes wrong, the aorta and pulmonary trunk are incorrectly positioned, resulting in oxygenated blood being directly returned to the lungs, with deoxygenated blood being delivered to the systemic circulation. This is termed transposition of the great arteries (TGA). The precise etiology of TGA is not known, but the use of animal models has elucidated that genes involved in determination of the left- embryonic body axis play key roles. Other factors such as retinoic acid levels are also crucial. This chapter reviews the animal models presenting with TGA that have been generated by genetic manipulation or with exogenous agents.

Human Genetics of Tricuspid Atresia and Univentricular Heart.

Tricuspid atresia (TA) is a rare congenital heart condition that presents with a complete absence of the right atrioventricular valve. Because of the rarity of familial and/or isolated cases of TA, little is known about the potential genetic abnormalities contributing to this condition. Potential responsible chromosomal abnormalities were identified in exploratory studies and include deletions in 22q11, 4q31, 8p23, and 3p as well as trisomies 13 and 18. In parallel, potential culprit genes include the ZFPM2, HEY2, NFATC1, NKX2-5, MYH6, and KLF13 genes. The aim of this chapter is to expose the genetic components that are potentially involved in the pathogenesis of TA in humans. The large variability in phenotypes and genotypes among cases of TA suggests a genetic network that involves many components yet to be unraveled.

Human Genetics of Defects of Situs.

Defects of situs are associated with complex sets of congenital heart defects in which the normal concordance of asymmetric thoracic and abdominal organs is disturbed. The cellular and molecular mechanisms underlying the formation of the embryonic left-right axis have been investigated extensively in the past decade. This has led to the identification of mutations in at least 33 different genes in humans with heterotaxy and situs defects. Those mutations affect a broad range of molecular components, from transcription factors, signaling molecules, and chromatin modifiers to ciliary proteins. A substantial overlap of these genes is observed with genes associated with other congenital heart diseases such as tetralogy of Fallot and double-outlet right ventricle, d-transposition of the great arteries, and atrioventricular septal defects. In this chapter, we present the broad genetic heterogeneity of situs defects including recent human genomics efforts.

Congenitally Corrected Transposition of the Great Arteries in Utero: Morphological Spectrum, Outcomes and Pitfalls in Fetal Diagnosis.

Congenitally corrected transposition of the great arteries (ccTGA) is a rare malformation with diverse morphology. We assessed features of fetuses with ccTGA and evaluated neonatal and pediatric outcomes. This was a retrospective review of fetuses with ccTGA at Birmingham Women's and Children's Hospital born from 2005 to 2019. Of thirty-six fetuses identified, six had unavailable prenatal data, one was postnatally diagnosed with isomerism and 29 fetuses were evaluated. ccTGA without associated cardiac lesions was found in 28% (8/29), ccTGA with significant VSD in 31% (9/29), ccTGA with pulmonary obstruction in 24% (7/29) and ccTGA with complex anomalies in 17% (5/29). Tricuspid regurgitation (TR) was observed in 17% (5/29) and heart block (HB) in 10% (3/29) prenatally. Six, that is 21% underwent genetic testing of which one was abnormal. Five extra-cardiac anomalies were reported prenatally and postnatally. Pregnancy was discontinued in five, of which two had moderate TR. There were thirty-one liveborn. Coarctation of the aorta was found in five postnatally but not suspected prenatally. In one, pulmonary stenosis was underestimated; otherwise, prenatal morphology was confirmed. Cardiac interventions were performed in 77% (24/31) liveborn with 39% (12/31) undergoing neonatal intervention. Overall, 6/31 liveborn died including all three with prenatal heart block and one with TR. Estimated survival for all liveborn at 1, 5 and 10 years was 87% (95% CI 76-100%), 83% (95% CI 72-98%) and 80% (95% CI 66-96%) respectively. Accurate prenatal diagnosis of ccTGA is critical for counseling. Early outcomes are favorable with 77% of liveborn undergoing surgery. Fetuses with prenatal diagnosis of complex associated abnormalities, HB and TR appear to do less well.

Hemodynamics in Adults with Systemic Right Ventricles: Differences Between Congenitally Corrected and Complete Transposition of the Great Arteries.

Despite their anatomical differences, congenitally corrected (ccTGA) and complete transposition of the great arteries (d-TGA) post-atrial switch are frequently studied together and managed similarly from a medical standpoint due to the shared systemic right ventricle (sRV). The aim was to assess differences in their underlying hemodynamics. The study is a retrospective review of 138 adults with ccTGA or d-TGA post-atrial switch undergoing cardiac catheterization at Mayo Clinic, MN between 2000 and 2021. ccTGA was categorized into isolated or complex ccTGA depending on concomitant ventricular septal defect and/or left ventricular outflow obstruction. There were 53 patients with d-TGA (91% post-Mustard procedure), 51 with complex and 34 with isolated ccTGA. Isolated ccTGA patients were older (51.8 ± 13.1 years) than those with d-TGA (37.5 ± 8.3 years) or complex ccTGA (40.8 ± 13.4 years). There were no differences in sRV or left ventricular size and function across groups. The ccTGA group more commonly had ≥ moderate tricuspid regurgitation than those with d-TGA; ≥ moderate mitral and ≥ moderate pulmonary regurgitation were most prevalent in complex ccTGA. There were no differences in sRV end-diastolic pressure (sRVEDP) or PAWP between groups. However, the ratio of PAWP:sRVEDP was higher in those with d-TGA compared to those with ccTGA. Cardiac index was higher in the d-TGA group than both groups of ccTGA patients with the latter showing higher indices of ventricular afterload. In conclusion, despite sharing a sRV, adults with d-TGA and ccTGA have substantial differences in hemodynamics and structural/valvular abnormalities. Further investigation regarding disease-specific responses to heart failure therapy in those with d-TGA and ccTGA is warranted.

Prenatal Detection of D-TGA and Novel Interventional Program Decrease Time to Balloon Septostomy.

Infants with dextro-transposition of the great arteries (d-TGA) are at high risk for hemodynamic compromise in the immediate postnatal period due to dependence on intracardiac mixing for oxygen delivery. This period of profound hypoxemia may have long-term implications, as previous studies demonstrated patients with d-TGA are at increased risk for neurocognitive delays despite effective surgical correction in the neonatal period. Balloon atrial septostomy (BAS) is an established intervention that improves intracardiac mixing and perioperative hemodynamics. This retrospective study aimed to quantify the time from birth to BAS and compare short-term outcomes for patients with prenatal and postnatal diagnoses of d-TGA. We identified 68 newborns born with d-TGA who were admitted to our facility between 2013 and 2022 and required BAS within 48 h after birth. Halfway through this study, our cardiac interventional team began traveling to a nearby delivery center where a bedside BAS could be performed prior to transferring the patient. We divided the patients into 3 groups-postnatal diagnosis (n = 27), prenatal diagnosis with rapid transport (n = 24), and prenatal diagnosis with interventional team performing a BAS at the delivery hospital (n = 17). The time from birth to BAS was significantly shorter for patients in the interventional program group (1.1 h) compared to the rapid transport (4.5 h) and postnatal diagnosis groups (9.3 h, p value < 0.01). The interventional program group also had lower lactate levels and less acidotic pH compared to the other groups. There was no significant difference in lowest oxygen saturation level, pre-surgical neurologic complication rate, time to surgery, or hospital length of stay. The interventional program proved to be a safe and effective model, as there were no procedural complications and the time to BAS decreased. Long-term follow-up is needed to determine if abating this initial period of hemodynamic instability will lead to improved neurodevelopmental outcomes.

High Reimplantation of Coronary Arteries After the Switch Procedure and Associated Stenoses.

Surgical repair through the arterial switch operation (ASO) is the only definitive treatment in patients with dextro-transposition of the great arteries (d-TGA). A crucial step during the reimplantation process is transfer of coronary arteries (CA) to the neo-aorta. A potential cause of CA stenosis is the presence of a high implantation of CA (HICA), defined by the presence of coronary ostium located above the sinotubular junction (STJ) of the aorta. We conducted a retrospective study on 157 patients (82 had digitally preserved angiograms) with d-TGA between 2010 and 2018 in a tertiary pediatric hospital in Canada. Of the 82 cases, 56 (68%) had HICA above the STJ. The mean distance from the STJ was + 7.1 ± 3.4 mm for the RCA, and + 6.8 ± 3.1 mm for the LMCA. Out of the 56 patients with HICA, 4 patients (7%) had stenosis, and out of 26 patients with in-sinus reimplanted CA, one patient (4%) had stenosis (p = 0.16). Patients in the HICA group with stenosis had a lower height of reimplantation of the CA compared to those without stenosis (+ 4.5 ± 1.3 mm vs. + 6.8 ± 3.1 mm, respectively; p < 0.05). This is a rare study assessing the rates of stenosis in the context of in-sinus versus HICA in the ASO. Reimplanting the coronary ostia at a higher level than the expected natural level does not seem to be associated with a significant risk in compromising CA perfusion.

Efficacy and Safety of Esmolol in Neonatal Cardiac Surgery with Cardiopulmonary Bypass (CPB) for d-Transposition of the Great Arteries (d-TGA).

OBJECTIVE: D-Transposition of the great arteries (d-TGA) is the most common congenital heart disease requiring surgical correction within the neonatal period. Sinus tachycardia often persists postoperatively, potentially affecting cardiac function. This study aimed to investigate the efficacy and safety of the short-acting beta-1-selective beta-blocker esmolol in controlling heart rate in neonatal cardiac surgery with cardiopulmonary bypass (CPB). METHODS: A retrospective cohort study was conducted on neonates undergoing surgery for d-TGA. The study cohort included 112 patients, divided into an esmolol intervention group (n = 57) and a control group (n = 55). Baseline characteristics, hemodynamic parameters and outcome measures were assessed. RESULTS: In the esmolol group, median heart rate at ICU admission was significantly higher compared to the control group (155 vs. 147 bpm, p = 0.018). After a median time of 11 h, heart rate was lower among the esmolol patients (135 vs. 144 bpm, p < 0.001). There were no differences in other hemodynamic parameters between the two groups. Patients treated with esmolol required longer catecholamine support while no difference regarding survival, duration of invasive ventilation and ICU stay were noticed. CONCLUSION: No relevant hemodynamic difference was seen between neonates treated with perioperative esmolol and the control group and outcome did not differ. This indicates non-inferiority of perioperative betablocker therapy in young age. Prospective and placebo-controlled assessment of perioperative esmolol therapy in neonates is needed.

Coronary Artery Dimensions on Computed Tomography Following the Neonatal Arterial Switch Operation for the Complete Transposition of the Great Arteries.

Coronary events are life-threatening long-term complications of the arterial switch operation for complete transposition of the great arteries. The aim of our study was to assess the dimensions of the reimplanted coronary arteries and their relationship with the various geometric characteristics to gain a better understanding of the involved mechanisms. Coronary computed tomography angiography (CCTA) scans of 78 asymptomatic pediatric patients were performed at the age of 10.7 (6.3-17.8) years. The position of the ostia, the branching angles, and the diameters of the coronary arteries were determined in a subgroup of 51 patients presenting the usual preoperative coronary anatomy. Mean Z-score of the left main coronary artery (LMCA), left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and right coronary artery (RCA) diameters were 0.7 ± 1.2, - 0.4 ± 1.1, - 0.3 ± 1.1, and - 0.3 ± 1.1, respectively. The Z-score of the ostial LMCA diameter had a positive correlation with the remoteness from the main pulmonary artery (p < 0.001) and the branching angle (p = 0.001). The ostial diameter Z-score of the LMCA had a negative correlation with the interval between the arterial switch operation and the CCTA (p = 0.004). Even though most of the coronary diameters fell within the accepted range, which suggests normal overall development, acute branching angle and more anterior origin were associated with smaller ostial coronary artery diameter Z-scores. To prove the clinical relevance of the smaller ostial diameter of high-risk left coronary arteries and the decrease of ostial coronary artery Z-scores over time needs further follow-up studies.