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.

Multi-modality imaging of the systemic right ventricle in congenital heart disease.

A comprehensive and structured imaging approach in the evaluation of the systemic right ventricle (sRV) in patients with complete transposition of the great arteries (TGA) after atrial switch procedure and congenitally corrected transposition of the great arteries (ccTGA) is a key for their optimal lifelong surveillance. Despite the improvements in cardiovascular imaging of adults with congenital heart disease (ACHD), the imaging of sRV remains an ongoing challenge due to its complex morphology and the difficulty in applying the existing knowledge for the systemic left ventricle. While cardiac magnetic resonance (CMR) is considered the gold standard imaging method, echocardiographic evaluation is primarily preferred in everyday clinical setting. Although qualitative assessment of its systolic function is primarily used, the introduction of advanced echocardiographic techniques, such as speckle tracking echocardiography (STE) and three-dimensional echocardiography (3DE), has provided new insights into the optimal assessment of the sRV. Standardized quantitative parameters remain to be elucidated, and morphometric and mechanistic studies are warranted to validate reference ranges for the sRV. This review highlights the challenges in the optimal evaluation of sRV and summarizes the available imaging tools. HIGHLIGHTS: CMR is the gold standard imaging method of sRV. Qualitative assessment of the systolic function of sRV is primarily used. Advanced echocardiographic techniques (STE and 3DE) provide optimal sRV assessment. Reference ranges for the sRV indices are warranted to be validated.

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.

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.

Growth of the Neo-Aortic Root and Prognosis of Transposition of the Great Arteries.

BACKGROUND: Neo-aortic root dilatation can lead to significant late morbidity after the arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA). OBJECTIVES: We sought to examine the growth of the neo-aortic root in d-TGA. METHODS: A single-center, retrospective cohort study of patients who underwent the ASO between July 1, 1981 and September 30, 2022 was performed. Morphology was categorized as dextro-transposition of the great arteries with intact ventricular septum (d-TGA-IVS), dextro-transposition of the great arteries with ventricular septal defect (d-TGA-VSD), and double-outlet right ventricle-transposition of the great arteries type (DORV-TGA). Echocardiographically determined diameters and derived z scores were measured at the annulus, sinus of Valsalva, and sinotubular junction immediately before the ASO and throughout follow-up. Trends in root dimensions over time were assessed using linear mixed-effects models. The association between intrinsic morphology and the composite of moderate-severe aortic regurgitation (AR) and neo-aortic valve or root intervention was evaluated with univariable and multivariable Cox proportional hazards models. RESULTS: Of 1,359 patients who underwent the ASO, 593 (44%), 666 (49%), and 100 (7%) patients had d-TGA-IVS, d-TGA-VSD, and DORV-TGA, respectively. Each patient underwent a median of 5 echocardiograms (Q1-Q3: 3-10 echocardiograms) over a median follow-up of 8.6 years (range: 0.1-39.3 years). At 30 years, patients with DORV-TGA demonstrated greater annular (P < 0.001), sinus of Valsalva (P = 0.039), and sinotubular junction (P = 0.041) dilatation relative to patients with d-TGA-IVS. On multivariable analysis, intrinsic anatomy, older age at ASO, at least mild AR at baseline, and high-risk root dilatation were associated with moderate-severe AR and neo-aortic valve or root intervention at late follow-up (all P < 0.05). CONCLUSIONS: Longitudinal surveillance of the neo-aortic root is warranted long after the ASO.

D-Transposition of the great arteries with restrictive foramen ovale in the fetus: the dilemma of predicting the need for postnatal urgent balloon atrial septostomy.

OBJECTIVE: Restrictive foramen ovale (FO) in dextro-transposition of the great arteries (d-TGA) with intact ventricular septum may lead to severe life-threatening hypoxia within the first hours of life, making urgent balloon atrial septostomy (BAS) inevitable. Reliable prenatal prediction of restrictive FO is crucial in these cases. However, current prenatal echocardiographic markers show low predictive value, and prenatal prediction often fails with fatal consequences for a subset of newborns. In this study, we described our experience and aimed to identify reliable predictive markers for BAS. METHODS: We included 45 fetuses with isolated d-TGA that were diagnosed and delivered between 2010 and 2022 in two large German tertiary referral centers. Inclusion criteria were the availability of former prenatal ultrasound reports, of stored echocardiographic videos and still images, which had to be obtained within the last 14 days prior to delivery and that were of sufficient quality for retrospective re-analysis. Cardiac parameters were retrospectively assessed and their predictive value was evaluated. RESULTS: Among the 45 included fetuses with d-TGA, 22 neonates had restrictive FO postnatally and required urgent BAS within the first 24 h of life. In contrast, 23 neonates had normal FO anatomy, but 4 of them unexpectedly showed inadequate interatrial mixing despite their normal FO anatomy, rapidly developed hypoxia and also required urgent BAS ('bad mixer'). Overall, 26 (58%) neonates required urgent BAS, whereas 19 (42%) achieved good O2 saturation and did not undergo urgent BAS. In the former prenatal ultrasound reports, restrictive FO with subsequent urgent BAS was correctly predicted in 11 of 22 cases (50% sensitivity), whereas a normal FO anatomy was correctly predicted in 19 of 23 cases (83% specificity). After current re-analysis of the stored videos and images, we identified three highly significant markers for restrictive FO: a FO diameter < 7 mm (p < 0.01), a fixed (p = 0.035) and a hypermobile (p = 0.014) FO flap. The maximum systolic flow velocities in the pulmonary veins were also significantly increased in restrictive FO (p = 0.021), but no cut-off value to reliably predict restrictive FO could be identified. If the above markers are applied, all 22 cases with restrictive FO and all 23 cases with normal FO anatomy could correctly be predicted (100% positive predictive value). Correct prediction of urgent BAS also succeeded in all 22 cases with restrictive FO (100% PPV), but naturally failed in 4 of the 23 cases with correctly predicted normal FO ('bad mixer') (82.6% negative predictive value). CONCLUSION: Precise assessment of FO size and FO flap motility allows a reliable prenatal prediction of both restrictive and normal FO anatomy postnatally. Prediction of likelihood of urgent BAS also succeeds reliably in all fetuses with restrictive FO, but identification of the small subset of fetuses that also requires urgent BAS despite their normal FO anatomy fails, because the ability of sufficient postnatal interatrial mixing cannot be predicted prenatally. Therefore, all fetuses with prenatally diagnosed d-TGA should always be delivered in a tertiary center with cardiac catheter stand-by, allowing BAS within the first 24 h after birth, regardless of their predicted FO anatomy.

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.

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.

Magnetic Resonance Spectroscopy of Brain Metabolism in Fetuses With Congenital Heart Disease.

BACKGROUND: Congenital heart disease (CHD) remains a significant risk factor for neurologic injury because altered fetal hemodynamics may be unable to support typical brain development during critical periods of growth and maturation. OBJECTIVES: The primary objective was to assess differences in the cerebral biochemical profile between healthy fetuses and fetuses with complex CHD and to relate these with infant outcomes. METHODS: Pregnant participants underwent fetal magnetic resonance imaging with cerebral proton magnetic resonance spectroscopy acquisitions as part of a prospective observational study. Cerebral metabolites of N-acetyl aspartate, creatine, choline, myo-inositol, scyllo-inositol, lactate, and relevant ratios were quantified using LCModel. RESULTS: We acquired 503 proton magnetic resonance spectroscopy images (controls = 333; CHD = 170) from 333 participants (controls = 221; CHD = 112). Mean choline levels were higher in CHD compared with controls (CHD 2.47 IU [Institutional Units] ± 0.44 and Controls 2.35 IU ± 0.45; P = 0.02), whereas N-acetyl aspartate:choline ratios were lower among CHD fetuses compared with controls (CHD 1.34 ± 0.40 IU vs controls 1.44 ± 0.48 IU; P = 0.001). Cerebral lactate was detected in all cohorts but increased in fetuses with transposition of the great arteries and single-ventricle CHD (median: 1.63 [IQR: 0.56-3.27] in transposition of the great arteries and median: 1.28 [IQR: 0-2.42] in single-ventricle CHD) compared with 2-ventricle CHD (median: 0.79 [IQR: 0-1.45]). Cerebral lactate also was associated with increased odds of death before discharge (OR: 1.75; P = 0.04). CONCLUSIONS: CHD is associated with altered cerebral metabolites in utero, particularly in the third trimester period of pregnancy, which is characterized by exponential brain growth and maturation, and is associated with survival to hospital discharge. The long-term neurodevelopmental consequences of these findings warrant further study.

Unveiling the gothic aortic arch and cardiac mechanics: insights from young patients after arterial switch operation for d-transposition of the great arteries.

The arterial switch operation (ASO) has become the standard surgical treatment for patients with d-transposition of the great arteries. While ASO has significantly improved survival rates, a subset of patients develop a unique anatomical anomaly known as the gothic aortic arch (GAA). Understanding cardiac mechanics in this population is crucial, as altered mechanics can have profound consequences for cardiac function and exercise capacity. The GAA has been associated with changes in ventricular function, hemodynamics, and exercise capacity. Studies have shown a correlation between the GAA and decreased ascending aorta distensibility, loss of systolic wave amplitude across the aortic arch, and adverse cardiovascular outcomes. Various imaging techniques, including echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography, play a crucial role in assessing cardiac mechanics and evaluating the GAA anomaly. Despite significant advancements, gaps in knowledge regarding the prognostic implications and underlying mechanisms of the GAA anomaly remain. This review aims to explore the implications of the GAA anomaly on cardiac mechanics and its impact on clinical outcomes in young patients after ASO. Advancements in imaging techniques, such as computational modeling, offer promising avenues to enhance our understanding of cardiac mechanics and improve clinical management.

[Left Main Trunk Orifice Reconstruction Using Aortic flap and Autologous Pulmonary Arterial Patch for Severe Left Main Trunk Stenosis After Arterial Switch Operation].

A 6-year-old boy with left main trunk (LMT) stenosis, who had undergone arterial switch operation (ASO) for transposition of the great arteries( TGA) before 6 years, underwent LMT orifice reconstruction. Coronary angiography showed severe stenosis of LMT, already when he was hospitalized with heart failure after 3 months of ASO. He was stable with oral treatment, therefore we performed the LMT reconstruction, before starting school, in terms of the risk of coronary ischemic event. We reconstructed the LMT ostium using an aortic flap and autologous pulmonary arterial patch. The postoperative computed tomography showed neither stenosis nor kinking at the repair site of LMT. He remains asymptomatic for over 6 months. We have reported that this method is effective to repair coronary artery anomalies (CAAs), since using an aortic flap. We could form a coronary artery floor, which is affixed to the aortic wall. This method allows us to change the coronary orifice position and the angle, so it is very useful method not for only CAAs, but also for coronary stenosis after ASO.

Decreased cardiac reserve in asymptomatic patients after arterial switch operation for transposition of the great arteries.

BACKGROUND: Exercise capacity is impaired in patients after arterial switch operation (ASO) for complete transposition of the great arteries. Maximal oxygen consumption is related with outcome. OBJECTIVES: This study assessed ventricular function by advanced echocardiography and cardiac magnetic resonance (CMR) imaging at rest and during exercise, to determine exercise capacity in ASO patients, and to correlate exercise capacity with ventricular function as potential early marker of subclinical impairment. METHODS: Forty-four patients (71% male, mean age 25 ± 4 years - range 18-40 years) were included during routine clinical follow-up. Assessment involved physical examination, 12­lead ECG, echocardiography, and cardiopulmonary exercise test (CPET) (day 1). On day 2 CMR imaging at rest and during exercise was performed. Blood was sampled for biomarkers. RESULTS: All patients reported New York Heart Association class I, the overall cohort had an impaired exercise capacity (80 ± 14% of predicted peak oxygen consumption). Fragmented QRS was present in 27%. Exercise CMR showed that 20% of patients had abnormal contractile reserve (CR) of the left ventricle (LV) and 25% had reduced CR of the right ventricle (RV). CR LV and CR RV were significantly associated with impaired exercise capacity. Pathological patterns on myocardial delayed enhancement and hinge point fibrosis were detected. Biomarkers were normal. CONCLUSION: This study found that in some asymptomatic ASO patients electrical, LV and RV changes at rest, and signs of fibrosis are present. Maximal exercise capacity is impaired and seems to be linearly related to the CR of the LV and the RV. Therefore, exercise CMR might play a role in detecting subclinical deterioration of ASO patients.

Hypertrophic cardiomyopathy in the systemic right ventricle in a patient with congenitally corrected transposition of the great arteries: A case report.

Congenitally corrected transposition of the great arteries is a rare clinical entity, which usually presents during adulthood with associated defects; atrioventricular block, heart failure, systemic valve failure, and arrhythmias usually complicate the clinical course. Even rarer is associated hypertrophic cardiomyopathy, which complicates the disease course and clinical decision-making. Herein, we present a patient with this condition who underwent heart transplantation, with adequate clinical resolution.

Fate of transposition of the great arteries with pulmonary stenosis after double-root translocation, Rastelli, and Réparation à l'Etage Ventriculaire.

OBJECTIVES: For transposition of the great arteries with unrestricted ventricular septal defect and pulmonary stenosis, double-root translocation is reported to reconstruct ideal double artery roots with growth potential. However, prospective long-term studies describing the long-term outcomes are still scarce. Therefore, the aim was to assess development of double artery roots, hemodynamics, and freedom from death and heart failure 17 years after double-root translocation, Rastelli, and Réparation à l'Etage Ventriculaire procedures. METHODS: In this prospective population-based study, 266 patients with transposition of the great arteries/ventricular septal defect/pulmonary stenosis (from July 2004 to August 2021) were consecutively included before surgery. All patients were divided into 3 groups based on the type of operation: double-root translocation (174), Rastelli (68), and Réparation à l'Etage Ventriculaire (24), who accepted postoperative evaluations annually. Generalized linear mixed model analysis was performed to determine growth potential of artery roots. RESULTS: Longitudinal repeated computed tomography measurements show the pulmonary root has significantly increased diameter (0.62 [0.03] mm/y, P < .001) over time and an adequate Z-score (-0.18) at the last follow-up only in the double-root translocation group. The pressure gradients of double outflow tracts in the double-root translocation group were the least among 3 groups. The probabilities of freedom from death/heart failure at the 15th year were 73.1%, 59.3%, and 60.9% in the double-root translocation, Rastelli, and Réparation à l'Etage Ventriculaire groups, respectively (double-root translocation vs Rastelli, P = .026; double-root translocation vs Réparation à l'Etage Ventriculaire, P = .009; Rastelli vs Réparation à l'Etage Ventriculaire, P = .449). CONCLUSIONS: By reconstructing ideal double artery roots, double-root translocation can provide postoperative long-term excellent hemodynamics and minimal death and heart failure for patients with transposition of the great arteries/ventricular septal defect/pulmonary stenosis.

Physiologic Repair of Congenitally Corrected Transposition of the Great Arteries in a Criss-Cross Heart.

Congenitally corrected transposition of great arteries is an uncommon congenital heart disease characterized by discordance at both the atrioventricular and ventriculoarterial connections. A rare subgroup of patients with congenitally corrected transposition of the great arteries also has a criss-cross heart. The morphology of these patients represents a diagnostic challenge that requires critical analysis to perform a satisfactory surgical procedure. We present a case of a 12-year-old patient with the above mentioned anatomy who underwent physiologic repair.