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Introduction: Transposition of the great arteries (TGA), especially with intact ventricular septum (TGA-IVS), presents unique challenges during fetal-to-neonatal transition, which can contribute to developing persistent pulmonary hypertension of the newborn (PPHN). Case Presentation: A male newborn with TGA-IVS, delivered via caesarean section, presented with hypoxemia and tachycardia immediately after birth (preductal SpO2: 50–60%, post-ductal SpO2: 70–75%). Echocardiography revealed a floppy interatrial septum and two interatrial connections with bidirectional shunting. Ductal flow showed systolic right-to-left shunting, suggesting high pulmonary vascular resistance. Immediate post-birth management included non-invasive respiratory support with continuous positive airway pressure at 100% oxygen and administration of prostaglandin E2 to maintain ductal patency. Despite initial low oxygen saturation levels, escalation of intensive treatments was deferred based on continuous trend monitoring of vital signs and echocardiographic indicators. Oxygenation and circulation gradually improved within the first 2 h after birth to normal values, obviating escalation of intensive interventions like intubation, nitric oxide and/or balloon atrial septostomy. Arterial switch operation at day 3 post-birth was successful. Conclusion: This case highlights the possible contribution of fetal-to-neonatal transition in TGA-IVS to developing PPHN, which may subside after transition. Moreover, this case highlights the potential for providing a gentle hemodynamic transition without invariably needing early invasive interventions after birth.

Aortic aneurysm is associated with aberrant blood flow and wall shear stress (WSS). This can be studied by coupling magnetic resonance imaging (MRI) with computational fluid dynamics (CFD). For patient-specific simulations, extra attention should be given to the variation in segmentation of the MRI data-set and its effect on WSS. We performed CFD simulations of blood flow in the aorta for ten different volunteers and provided corresponding WSS distributions. The aorta of each volunteer was segmented four times. The same inlet and outlet boundary conditions were applied for all segmentation variations of each volunteer. Steady-state CFD simulations were performed with inlet flow based on phase-contrast MRI during peak systole. We show that the commonly used comparison of mean and maximal values of WSS, based on CFD in the different segments of the thoracic aorta, yields good to excellent correlation (0.78–0.95) for rescan and moderate to excellent correlation (0.64–1.00) for intra- and interobserver reproducibility. However, the effect of geometrical variations is higher for the voxel-to-voxel comparison of WSS. With this analysis method, the correlation for different segments of the whole aorta is poor to moderate (0.43–0.66) for rescan and poor to good (0.48–0.73) for intra- and interobserver reproducibility. Therefore, we advise being critical about the CFD results based on the MRI segmentations to avoid possible misinterpretation. While the global values of WSS are similar for different modalities, the variation of results is high when considering the local distributions. •A statistical analysis of MRI-based CFD in the thoracic aortas for ten volunteers.•Wall shear stress from CFD is strongly affected by variations in segmentation.•High-quality segmentation is needed for an accurate estimate of wall shear stress.•Increasing order of evaluation method decreases the agreement between segmentations.•Voxel-to-voxel analysis shows that wall shear stress agrees only qualitatively.

Blood flow dynamics make it possible to better understand the development of aortopathy and cardiovascular events in patients with Marfan syndrome (MFS). Aortic 3D blood flow characteristics were investigated in relation to aortic geometry in children and adolescents with MFS. Twenty-five MFS patients (age 15.6 ± 4.0 years; 11 females) and 21 healthy controls (age 16.0 ± 2.6 years; 12 females) underwent magnetic resonance angiography and 4D flow CMR for assessment of thoracic aortic size and 3D blood flow velocities. Data analysis included calculation of aortic diameter and BSA-indexed aortic dimensions (Z-score) along the thoracic aorta, 3D mean systolic wall shear stress (WSSmean) in ten aortic segments and assessment of aortic blood flow patterns. Aortic root (root), ascending (AAo) and descending (DAo) aortic size was significantly larger in MFS patients than healthy controls (Root Z-score: 3.56 ± 1.45 vs 0.49 ± 0.78, p < 0.001; AAo Z-score 0.21 ± 0.95 vs −0.54 ± 0.64, p = 0.004; proximal DAo Z-score 2.02 ± 1.60 vs 0.56 ± 0.66, p < 0.001). A regional variation in prevalence and severity of flow patterns (vortex and helix flow patterns) was observed, with the aortic root and the proximal DAo (pDAo) being more frequently affected in MFS. MFS patients had significantly reduced WSSmean in the proximal AAo (pAAo) outer segment (0.65 ± 0.12 vs. 0.73 ± 0.14 Pa, p = 0.029) and pDAo inner segment (0.74 ± 0.17 vs. 0.87 ± 0.21 Pa, p = 0.021), as well as higher WSSmean in the inner segment of the distal AAo (0.94 ± 0.14 vs. 0.84 ± 0.15 Pa, p = 0.036) compared to healthy subjects. An inverse relationship existed between pDAo WSSmean and both pDAo diameter (R = −0.53, p < 0.001) and % diameter change along the pDAo segment (R = −0.64, p < 0.001). MFS children and young adults have altered aortic flow patterns and differences in aortic WSS that were most pronounced in the pAAo and pDAo, segments where aortic dissection or rupture often originate. The presence of vortex flow patterns and abnormal WSS correlated with regional size of the pDAo and are potentially valuable additional markers of disease severity.

In selected patients with transposition of the great arteries (TGA), ventricular septal defect (VSD) and left ventricular outflow tract obstruction (LVOTO), the arterial switch operation (ASO) may be the procedure of choice. This study reviews the clinical outcomes of TGA-VSD-LVOTO patients after ASO and compares mechanisms of LVOTO in this patient group to a historical series of cardiac specimens. This retrospective analysis included all cases with TGA-VSD-LVOTO who underwent ASO between January 1977 and December 2023. Additionally, a series of non-operated cardiac specimens with TGA-VSD-LVOTO was selected and examined for morphological comparison. Eleven patients with TGA-VSD-LVOTO underwent ASO. Eight of them had TGA-VSD, and three had Taussig-Bing anomaly. LVOTO mechanisms were multifactorial, including posteriorly deviated infundibular septum and fibrous tissue masses. Median age at ASO was 0.4 (0.07-1.8) years. Ten patients underwent primary LVOTO relief during ASO; no in-hospital mortality occurred. Two patients died >30 days post-ASO at 3.1 months and 6.0 years. Median follow-up was 19.0 (11.1-26.8) years, all survivors in NYHA class I. The patient without initial LVOTO relief did require reoperation during follow-up for progressive LVOTO at 3.5 months post-ASO. Two patients had moderate residual LVOTO at latest follow-up (gradient 30-50 mmHg). No significant neoaortic valve regurgitation was observed. From the anatomical specimen series, 10 of 33 TGA-VSD-LVOTO specimen were deemed eligible for ASO, revealing similar LVOTO mechanisms as the clinical cases. ASO is feasible in selected patients with TGA-VSD-LVOTO showing good long-term outcomes with preserved neoaortic valve function and no reoperations for LVOTO after initial relief.

Abstract Background Left ventricular apical pacing (LVAP) is considered to preserve left ventricular (LV) systolic function in both patients with and without congenital heart disease. However, sporadic LVAP-associated cardiac dysfunction in children with complex structural heart disease was recently reported. We present the case of a 2.5-year-old child with complex congenital heart disease and LVAP-induced cardiomyopathy. Case summary Corrective surgery for double outlet right ventricle, subpulmonary ventricular septal defect, and transposition of the great arteries was done at the age of 1.5 months. Late complete atrioventricular block occurred, necessitating VVI pacemaker insertion with LV apical epicardial leads. He presented with heart failure and dilated cardiomyopathy 1.5 years after pacemaker insertion and required persistent circulatory support with intravenous inotropes. Speckle tracking echocardiography identified an important LV apical to basal dyssynchrony. After excluding any coronary artery involvement, cardiac resynchronization therapy was performed. Speckle tracking echocardiography guided lead placement resulted in improved LV contraction synchrony. Cardiac function recovered progressively in combination with oral heart failure medication and is almost normal at 10-month follow-up. Discussion Right ventricular pacing is a well-known cause of pacing-induced cardiomyopathy. The LV apex and LV free wall are thought to be most optimal locations for ventricular pacing in children. However, LVAP can also be the cause of a pacing-induced cardiomyopathy and decreased systolic LV function in children with complex congenital heart disease due to lack of LV contraction synchrony. Cardiac resynchronization therapy can reverse this LV dysfunction and remodelling.

ObjectiveTo study neo-aortic growth and the evolution of neo-aortic valve regurgitation (AR) in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) from newborn to adulthood and to identify patients at risk.MethodsNeo-aortic dimensions (annulus/root/sinotubular junction) and neo-aortic valve regurgitation were assessed serially in 345 patients with TGA who underwent ASO between 1977 and 2015. Linear mixed-effect models were used to assess increase of neo-aortic dimensions over time and to identify risk factors for dilatation. Risk factor analysis for AR by using time-dependent Cox regression models.ResultsAfter a rapid increase in the first year after ASO and proportional growth in childhood, neo-aortic dimensions continue to increase in adulthood without stabilisation. Annual diameter increase in adulthood was 0.39±0.06, 0.63±0.09 and 0.54±0.11 mm for, respectively, neo-aortic annulus, root and sinotubular junction, all significantly exceeding normal growth. AR continues to develop over time: freedom from AR ≥moderate during the first 25 years post-ASO was 69%. Risk factors for root dilatation were complex TGA anatomy (TGA-ventricular septal defect (VSD), double outlet right ventricle with subpulmonary VSD) and male gender. Risk factors for AR ≥moderate were: complex TGA anatomy and neo-aortic growth. Per millimetre increase in aortic root dimension, there was a 9% increase in the hazard of AR ≥moderate. Bicuspid pulmonary valve did not relate to the presence of root dilatation or AR.ConclusionAfter ASO, neo-aortic dilatation proceeds beyond childhood and is associated with an increase in AR incidence over time. Careful follow-up of the neo-aortic valve and root function is mandatory, especially in males and in patients with complex TGA anatomy.

High concentrations of oxygen are often needed to optimize oxygenation in infants with persistent pulmonary hypertension (PPHN), but this can also increase the risk of hyperoxemia. We determined the occurrence of hyperoxemia in infants treated for PPHN. Medical records of infants ≥ 34 + 0 weeks gestational age (GA) who received inhaled nitric oxide (iNO) were retrospectively reviewed for oxygenation parameters during iNO therapy. Oxygen was manually titrated to target arterial oxygen tension (PaO 2 ) 10–13 kPa and peripheral oxygen saturation (SpO 2 ) 92–98%. The main study outcomes were the incidence and duration of hyperoxemia and hypoxemia and the fraction of inspired oxygen (FiO 2 ). A total of 181 infants were included. The median FiO 2 was 0.43 (IQR 0.34–0.56) and the maximum FiO 2 was 1.0 in 156/181 (86%) infants, resulting in at least one PaO 2  > 13 kPa in 149/181 (82%) infants, of which 46/149 (31%) infants had minimal one PaO 2  > 30 kPa. SpO 2 was > 98% in 179/181 (99%) infants for 17.7% (8.2–35.6%) of the iNO time. PaO 2  < 10 kPa occurred in 160/181 (88%) infants, of which 81/160 (51%) infants had minimal one PaO 2  < 6.7 kPa. SpO 2 was < 92% in 169/181 (93%) infants for 1.6% (0.5–4.3%) of the iNO time.     Conclusion : While treatment of PPHN is focused on preventing and reversing hypoxemia, hyperoxemia occurs inadvertently in most patients. What is Known: • High concentrations of oxygen are often needed to prevent hypoxemia-induced deterioration of PPHN, but this can also increase the risk of hyperoxemia. • Infants with persistent pulmonary hypertension may be particularly vulnerable to the toxic effects of oxygen, and hyperoxemia could further induce pulmonary vasoconstriction, potentially worsening the condition. What is New: • Hyperoxemia occurs in the majority of infants with PPHN during treatment with iNO. • Infants with PPHN spent a considerably longer period with saturations above the target range compared to saturations below the target range.

Correspondence to Dr Roel L F van der Palen, Pediatric Cardiology, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands; R.L.F.van_der_Palen@lumc.nl Clinical introduction A girl born at a gestational age of 38 weeks was antenatally diagnosed with a transposition of the great arteries with intact ventricular septum. AAo, ascending aorta; Aneur, pulmonary artery aneurysm; DAo, descending aorta; LA, left atrium; LPA, left pulmonary artery; LV, left ventricle; neoAo, neoaorta; neoPA, neopulmonary artery; neoPV, neopulmonary valve; Root, neoaortic root; RPA, right pulmonary artery; RV, right ventricle. Progression of aortic root dilatation and aortic valve regurgitation after the arterial switch operation.

[...]a reanalysis of the study data was performed using joint modelling. Furthermore, the neoaortic root dimension was also shown to be an independent risk factor for the development of AR≥mild. [...]the neoaortic annulus dimension was an independent risk factor for the development of AR≥mild and AR≥moderate. [...]based on the joint model analysis, both annulus and root dimensions are independently associated with AR and, additionally, growth rate of the former native pulmonary valve annulus and adjacent root is as well.

The aim of the current study was to assess the scan–rescan reproducibility of left ventricular (LV) kinetic energy (KE), viscous energy loss (EL) and vorticity during diastole from four-dimensional flow magnetic resonance imaging (4D flow MRI) in healthy subjects. Twelve volunteers (age 27 ± 3 years) underwent whole-heart 4D flow MRI twice in one session. In-scan consistency was evaluated by correlation between KE and EL. ELindex was computed to measure the amount of EL relative to KE over diastole. Scan–rescan analysis was performed to test reproducibility of volumetric measurements of KE, EL, ELindex and vorticity in the LV over early (E) and late (A) diastolic filling. In-scan consistency between KE and EL was strong-excellent (E-filling scan1: r = 0.92, P < 0.001; scan2: ρ = 0.96, P < 0.001 and A-filling scan1: ρ = 0.87, P < 0.001; scan2: r = 0.99, P < 0.001). For the majority of subjects (10 out of 12), KE and EL measures showed good to strong reproducibility. However, with a wide range of agreement [intraclass correlation (ICC): 0.64–0.95] and coefficients of variation (CV) ≤ 25%. ELindex showed strong reproducibility for all 12 subjects with a strong ICC (0.94, P < 0.001) and a CV of 9%. Scan–rescan reproducibility of volumetric vorticity showed good–excellent ICCs (0.83–0.95) with CVs ≤ 11%. In conclusion, the current study shows strong–excellent in-scan consistency and overall good agreement between scans for 4D flow MRI assessment of left ventricular kinetic energy, energy loss and vorticity over diastole. However, substantial differences between the scans were also found in some parameters in two out of twelve subjects. Strong reproducibility was found in the dimensionless ELindex, which measures the amount of viscous energy loss relative to the average kinetic energy over diastole.