Atrial Septal Defect vs Ventricular Septal Defect: Getting the Right Mix in Transposition of the Great Arteries.

Transposition of the great arteries (TGA) is the second most common cyanotic congenital cardiac defect and affects around 4.7 in 10,000 live births. Patients present at birth with profound cyanosis due to inadequate oxygen delivery to the systemic circulation. Typical management after birth involves the administration of prostaglandins and oxygen while awaiting surgical repair. Balloon atrial septostomy may be performed depending on the adequacy of the interatrial communication. In this case report, we present a challenging case of TGA ventricular septal defect (VSD) and pulmonary stenosis (PS), demonstrating the importance of bedside clinical examination along with applying basic management principles. The patient underwent a right modified Blalock-Taussig-Thomas shunt (BTT) along with left pulmonary artery (LPA) reconstruction and main pulmonary artery band as an initial palliative procedure. The patient deteriorated post-operatively, with increasing desaturations and oxygen requirements. Though imaging suggested sufficient inter-circulatory mixing, the clinical picture of desaturation without respiratory distress and lack of response to oxygen and pulmonary vasodilatory therapy strongly suggested otherwise. The child therefore underwent a balloon atrial septostomy. Their clinical condition improved and they were discharged three days later. We describe this case's clinical course, medical and surgical management, and learning points.

Predicting Peri-Operative Cardiorespiratory Adverse Events in Children with Idiopathic Pulmonary Arterial Hypertension Undergoing Cardiac Catheterization Using Echocardiography: A Cohort Study.

General anesthesia in children with idiopathic pulmonary arterial hypertension (PAH) carries an increased risk of peri-operative cardiorespiratory complications though risk stratifying individual children pre-operatively remains difficult. We report the incidence and echocardiographic risk factors for adverse events in children with PAH undergoing general anesthesia for cardiac catheterization. Echocardiographic, hemodynamic, and adverse event data from consecutive PAH patients are reported. A multivariable predictive model was developed from echocardiographic variables identified by Bayesian univariable logistic regression. Model performance was reported by area under the curve for receiver operating characteristics (AUCroc) and precision/recall (AUCpr) and a pre-operative scoring system derived (0-100). Ninety-three children underwent 158 cardiac catheterizations with mean age 8.8 ± 4.6 years. Adverse events (n = 42) occurred in 15 patients (16%) during 16 catheterizations (10%) including cardiopulmonary resuscitation (n = 5, 3%), electrocardiographic changes (n = 3, 2%), significant hypotension (n = 2, 1%), stridor (n = 1, 1%), and death (n = 2, 1%). A multivariable model (age, right ventricular dysfunction, and dilatation, pulmonary and tricuspid regurgitation severity, and maximal velocity) was highly predictive of adverse events (AUCroc 0.86, 95% CI 0.75 to 1.00; AUCpr 0.68, 95% CI 0.50 to 0.91; baseline AUCpr 0.10). Pre-operative risk scores were higher in those who had a subsequent adverse event (median 47, IQR 43 to 53) than in those who did not (median 23, IQR 15 to 33). Pre-operative echocardiography informs the risk of peri-operative adverse events and may therefore be useful both for consent and multi-disciplinary care planning.

Impact of Tracheal Arborization and Lung Hypoplasia in Repair of Pulmonary Artery Sling in Combination With Long-Segment Tracheal Stenosis.

Background: Reimplantation of the left pulmonary artery (LPA) and slide tracheoplasty has been our standard approach of care for patients with pulmonary artery sling (PAS) and tracheal stenosis. We present our experience, with emphasis on tracheal arborization and hypoplastic lungs; and their impact on long-term outcome of children with PAS and tracheal stenosis. Methods: It is a retrospective comparative study. Data were classified and analyzed based on the type of tracheobronchial arborization and normal versus hypoplastic lungs. Results: Seventy-five children operated between January 1994 and December 2019 (67 with normal lungs and 8 with lung hypoplasia/agenesis) were included. Patients with hypoplastic lungs had higher rates of preoperative ventilation (87.5%), postoperative ventilation (10 vs 8 days, P = .621), and mortality (50% vs 9%, P = .009) compared with those with normal lungs. Nineteen patients had tracheal bronchus (TB) variety and 30 patients had congenital long-segment tracheal stenosis (CLSTS) variety of tracheobronchial arborization. Endoscopic intervention was needed in 47.4% of patients with TB type and 60% with CLSTS type. CLSTS patients had higher rates of preoperative ventilation (60% vs 47.4%, P = .386), longer periods of postoperative ventilation (13 vs 6.5 days, P = .006), and ICU stay (15 vs 11 days, P = .714) compared with TB type. Conclusion: Surgical repair of PAS with tracheal stenosis has good long-term outcomes. All variations of tracheal anatomy can be managed with slide tracheoplasty. Persistence of airway problems requires intervention during follow-up as tracheal stenosis continues to be the Achilles heel.

Importance of Acute Anterior Angulation in Double Aortic Arch Needing Attention at Primary Surgery.

BACKGROUND: Vascular rings are rare congenital abnormalities of the aortic arch. There are many embryological variants including a double aortic arch. In symptomatic children, division of ring and release of airway structures may be sufficient. Persistence of symptoms can be related to an anterior angle formed between the two arches. The aim of this study is to evaluate the clinical efficacy in improving symptoms and on changing this angle at the primary surgery. METHODS: All children who had surgery for double aortic arch between 2005 and 2020, were studied. Relevant factors were analyzed for persistent symptoms including anatomical substrates and surgical details. RESULTS: A total of 87 out of 224 children had surgery for a double aortic arch. At presentation, airway symptoms (n = 74/87) were more common than esophageal symptoms (n = 27/87). Early onset symptoms within 1 year were seen in 49 children. In addition to division of one arch, surgical steps also included realigning the anterior left arch, thereby eliminating the acute angle in 36 children (after 2014). After surgery, symptom relief within 12 months following surgery was seen in 64% of children (56 out of 87) but in 27 out of 36 children (75%) with additional surgical modification, as against 29 out of 51 (57%) in those with division of the arch. Symptoms persisted beyond 1 year needing reintervention in eight children. CONCLUSION: Anterior arch angulation plays an important role in double aortic arch by causing a "nutcracker" phenomenon. Repair in double aortic arch should consider this aspect and include modification of surgical steps by realigning the corresponding aortic arch branches and an anterior pexy in selected cases.

Repair of pulmonary artery sling with tracheal and intracardiac defects.

BACKGROUND: Pulmonary artery sling is commonly associated with tracheal stenosis and intracardiac anomalies. While surgical repair is standardized, coexistent anomalies often determine outcomes. With the paucity of risk stratification, this study aimed to review our experience and stratify risk factors for the surgical outcome of complex pulmonary artery sling repair in the presence of airway or intracardiac lesions. METHODS: Seventy-nine consecutive children with pulmonary artery sling were evaluated retrospectively following surgical repair. Median age at surgery was 5 months (interquartile range 3-9). Surgical approaches included pulmonary artery sling alone (n = 10), pulmonary artery sling with tracheoplasty (n = 41), and pulmonary artery sling with both intracardiac and tracheal surgery (n = 28). RESULTS: There were 7 early (8.8%) deaths. Two patients after left pulmonary artery reimplantation needed revision of the anastomosis. The median intensive care and hospital stay were 11 (interquartile range 9.2-24.8) and 17.9 (interquartile range 4.3-19.8) days, and considerably longer when associated tracheal surgery (p = 0.002). Follow-up was complete in 66/69 and 3 (3.8%) children died late: 2.7, 10.2, and 17 months after surgery. Univariate analysis showed abnormal lung and coexisting structural heart disease as risk factors. Multivariate analysis revealed total cardiopulmonary bypass time as an independent predictor of overall mortality. CONCLUSION: Complex pulmonary artery sling repair can be performed with a good surgical outcomes even when associated with airway malformations or structural heart diseases. Lung abnormality and longer cardiopulmonary bypass time as a surrogate marker of complex surgery, are possible risk factors.

Melody Valve in Aortic Position to Facilitate Mechanical Circulatory Support as a Bridge to Cardiac Transplantation.

We report a patient with congenital heart disease and end stage heart failure after interventions for congenital heart disease resulting in aortic regurgitation that could not be treated with mechanical support to bridge to transplantation. We used a Melody valve (Medtronic Inc, Minneapolis, MN) in aortic position to achieve aortic competence to allow use of a left ventricular assist device to bridge the patient successfully to cardiac transplantation.

Patient-specific simulations for planning treatment in congenital heart disease.

Patient-specific computational models have been extensively developed over the last decades and applied to investigate a wide range of cardiovascular problems. However, translation of these technologies into clinical applications, such as planning of medical procedures, has been limited to a few single case reports. Hence, the use of patient-specific models is still far from becoming a standard of care in clinical practice. The aim of this study is to describe our experience with a modelling framework that allows patient-specific simulations to be used for prediction of clinical outcomes. A cohort of 12 patients with congenital heart disease who were referred for percutaneous pulmonary valve implantation, stenting of aortic coarctation and surgical repair of double-outlet right ventricle was included in this study. Image data routinely acquired for clinical assessment were post-processed to set up patient-specific models and test device implantation and surgery. Finite-element and computational fluid dynamics analyses were run to assess feasibility of each intervention and provide some guidance. Results showed good agreement between simulations and clinical decision including feasibility, device choice and fluid-dynamic parameters. The promising results of this pilot study support translation of computer simulations as tools for personalization of cardiovascular treatments.

Duct Stenting Versus Modified Blalock-Taussig Shunt in Neonates With Duct-Dependent Pulmonary Blood Flow: Associations With Clinical Outcomes in a Multicenter National Study.

BACKGROUND: Infants born with cardiac abnormalities causing dependence on the arterial duct for pulmonary blood flow are often palliated with a shunt usually between the subclavian artery and either pulmonary artery. A so-called modified Blalock-Taussig shunt allows progress through early life to an age and weight at which repair or further more stable palliation can be safely achieved. Modified Blalock-Taussig shunts continue to present concern for postprocedural instability and early mortality such that other alternatives continue to be explored. Duct stenting (DS) is emerging as one such alternative with potential for greater early stability and improved survival. METHODS: The purpose of this study was to compare postprocedural outcomes and survival to next-stage palliative or reparative surgery between patients undergoing a modified Blalock-Taussig shunt or a DS in infants with duct-dependent pulmonary blood flow. All patients undergoing cardiac surgery and congenital interventions in the United Kingdom are prospectively recruited to an externally validated national outcome audit. From this audit, participating UK centers identified infants <30 days of age undergoing either a Blalock-Taussig shunt or a DS for cardiac conditions with duct-dependent pulmonary blood flow between January 2012 and December 31, 2015. One hundred seventy-one patients underwent a modified Blalock-Taussig shunt, and in 83 patients, DS was attempted. Primary and secondary outcomes of survival and need for extracorporeal support were analyzed with multivariable logistic regression. Longer-term mortality before repair and reintervention were analyzed with Cox proportional hazards regression. All multivariable analyses accommodated a propensity score to balance patient characteristics between the groups. RESULTS: There was an early (to discharge) survival advantage for infants before next-stage surgery in the DS group (odds ratio, 4.24; 95% confidence interval, 1.37-13.14; P=0.012). There was also a difference in the need for postprocedural extracorporeal support in favor of the DS group (odds ratio, 0.22; 95% confidence interval, 0.05-1.05; P=0.058). Longer-term survival outcomes showed a reduced risk of death before repair in the DS group (hazard ratio, 0.25; 95% confidence interval, 0.07-0.85; P=0.026) but a slightly increased risk of reintervention (hazard ratio, 1.50; 95% confidence interval, 0.85-2.64; P=0.165). CONCLUSIONS: DS is emerging as a preferred alternative to a surgical shunt for neonatal palliation with evidence for greater postprocedural stability and improved patient survival to destination surgical treatment.

Outcome after transcatheter occlusion of patent ductus arteriosus in infants less than 6 kg: A national study from United Kingdom and Ireland.

OBJECTIVES: This study aimed to report our national experience with transcatheter patent ductus arteriosus (PDA) occlusion in infants weighing <6 kg. BACKGROUND: The technique of transcatheter PDA closure has evolved in the past two decades and is increasingly used in smaller patients but data on safety and efficacy are limited. METHODS: Patients weighing < 6 kg in whom transcatheter PDA occlusion was attempted in 13 tertiary paediatric cardiology units in the United Kingdom and Ireland were retrospectively analyzed to review the outcome and complications. RESULTS: A total of 408 patients underwent attempted transcatheter PDA closure between January 2004 and December 2014. The mean weight at catheterization was 4.9 ± 1.0 kg and mean age was 5.7 ± 3.0 months. Successful device implantation was achieved in 374 (92%) patients without major complication and of these, complete occlusion was achieved in 356 (95%) patients at last available follow-up. Device embolization occurred in 20 cases (5%). The incidence of device related obstruction to the left pulmonary artery or aorta and access related peripheral vascular injury were low. There were no deaths related to the procedure. CONCLUSIONS: Transcatheter closure of PDA can be accomplished in selected infants weighing <6 kg despite the manufacturer's recommended weight limit of 6 kg for most ductal occluders. The embolization rate is higher than previously reported in larger patients. Retrievability of the occluder and duct morphology needs careful consideration before deciding whether surgical ligation or transcatheter therapy is the better treatment option.

Utility of adenosine stress perfusion CMR to assess paediatric coronary artery disease.

AIMS: Cardiovascular magnetic resonance (CMR), using adenosine stress perfusion and late-gadolinium enhancement (LGE), is becoming the 'gold standard' non-invasive imaging modality in the assessment of adults with coronary artery disease (CAD). However, despite its proved feasibility in paediatric patients, clinical utility has not been demonstrated. Therefore, this study aims to establish the role of adenosine stress perfusion CMR as a screening test in paediatric patients with acquired or congenital CAD. METHODS AND RESULTS: A total of 58 paediatric patients underwent 61 consecutive clinically indicated coronary artery assessments for diagnostic and clinical decision-making purposes. The diagnosis was based on X-ray or computed tomography coronary angiography for anatomy, adenosine stress CMR imaging for myocardial perfusion and LGE for tissue characterization. Two studies were aborted because of unwanted side effects of adenosine stress, thus 59 studies were completed in 56 patients [median age 14.1 years (interquartile range 10.9-16.2)]. When compared with coronary anatomical imaging, adenosine stress perfusion CMR performed as follows: sensitivity 100% (95% confidence interval, CI: 71.6-100%), specificity 98% (95% CI: 86.7-99.9%), positive predictive value (PPV) 92.9% (95% CI: 64.2-99.6%), and negative predictive value 100% (95% CI: 89.9-100%). CONCLUSION: In paediatric CAD, adenosine stress perfusion CMR imaging is adequate as an initial, non-invasive screening test for the identification of significant coronary artery lesions, with anatomical imaging used to confirm the extent of the culprit lesion.

Doubly committed subarterial ventricular septal defect: A risk factor for aortic distortion in patients considered for percutaneous pulmonary valve implantation?

Percutaneous pulmonary valve implantation has gradually become the first line strategy for re-intervention for right ventricular outflow tract dysfunction during long-term follow-up after congenital cardiac surgery in many centers. We describe a case of a patient with double outlet right ventricle (Fallot's type) with a doubly committed subarterial ventricular septal defect, where the unique anatomy precluded percutaneous pulmonary valve implantation. © 2016 Wiley Periodicals, Inc.

Feasibility and safety of cardiopulmonary exercise testing in children with pulmonary hypertension.

BACKGROUND: Cardiopulmonary exercise testing helps prognosticate and guide treatment in adults with pulmonary hypertension. Concerns regarding its feasibility and safety limit its use in children with pulmonary hypertension. We aimed to assess the feasibility and safety of cardiopulmonary exercise testing in a large paediatric pulmonary hypertension cohort. METHODS: We reviewed all consecutive cardiopulmonary exercise tests performed between March, 2004 and November, 2013. The exclusion criteria were as follows: height <120 cm, World Health Organization class IV, history of exercise-induced syncope, or significant ischaemia/arrhythmias. Significant events recorded were as follows: patient-reported symptoms, arrhythmias, electrocardiogram abnormalities, and abnormal responses of arterial O2 saturation. RESULTS: A total of 98 children underwent 167 cardiopulmonary exercise tests. The median age was 14 years (inter-quartile range 10-15 years). Peak oxygen uptake was 20.4±7.3 ml/kg/minute, corresponding to 51.8±18.3% of the predicted value. Peak respiratory quotient was 1.08±0.16. All the tests except two were maximal, being terminated prematurely for clinical reasons. Baseline Oxygen saturation was 93.3±8.8% and was 81.2±19.5% at peak exercise. A drop in arterial O2 saturation >20% was observed in 23.5% of the patients. Moreover, five patients (3.0%) experienced dizziness, one requiring termination of cardiopulmonary exercise testing; five children (3.0%) experienced chest pain, with early cardiopulmonary exercise test termination in one patient. No significant arrhythmias or electrocardiogram changes were observed. CONCLUSION: Exercise testing in non-severely symptomatic children with pulmonary hypertension is safe and practical, and can be performed in a large number of children with pulmonary hypertension in a controlled environment with an experienced team. Side-effects were not serious and were resolved promptly with test termination.

Patient-specific computational models to support interventional procedures: a case study of complex aortic re-coarctation.

AIMS: We report the application of patient-specific computational models to plan the treatment of complex aortic re-coarctation (rCoA) with a proximal aberrant right subclavian artery in a patient who had previously undergone bare metal stenting. METHODS AND RESULTS: Clinically acquired images were used to set up patient-specific computational models for finite element (FE) and fluid dynamics (CFD) analyses. The 3D geometry was reconstructed from computed tomography and echocardiography images. Computer-generated deployment of a CP covered stent (NuMED, Hopkinton, NY, USA) at different diameters was tested using FE simulations. CFD analyses based on preoperative magnetic resonance flow measurements allowed assessment of rCoA pressure relief and right subclavian artery perfusion in the different scenarios. The simulations suggested an expansion diameter for the CP stent (8 zigs, length=28 mm) of between 16 and 18 mm to relieve the obstruction, cover the aneurysm and maintain satisfactory flow to the right subclavian artery. Following the modelling study, a 16 mm CP covered stent was successfully implanted. CONCLUSIONS: Patient-specific models can be successfully used to plan re-stenting of complex rCoA, showing the benefits of integrating computational techniques into patient management.

Peak oxygen uptake, ventilatory efficiency and QRS-duration predict event free survival in patients late after surgical repair of tetralogy of Fallot.

OBJECTIVE: Patients with repaired tetralogy of Fallot (ToF) have an increased long-term risk of cardiovascular morbidity and mortality. Risk stratification in this population is difficult. Initial evidence suggests that cardiopulmonary exercise testing (CPET) may be helpful to risk-stratify patients with repaired ToF. METHODS AND RESULTS: We studied 875 patients after surgical repair for ToF (358 females, age 25.5 ± 11.7 year, range 7-75 years) who underwent CPET between 1999 and 2009. During a mean follow-up of 4.1 ± 2.6 years after CPET, 30 patients (3.4%) died or had sustained ventricular tachycardia (VT). 225 patients (25.7%) had other cardiac related events (emergency admission, surgery, or catheter interventions). On multivariable Cox regression-analysis, %predicted peak oxygen uptake (V˙O2 %) (p=0.001), resting QRS duration (p=0.030) and age (p<0.001) emerged as independent predictors of mortality or sustained VT. Patients with a peak V˙O2 ≤ 65% of predicted and a resting QRS duration ≥ 170 ms had a 11.4-fold risk of death or sustained VT. Ventilatory efficiency expressed as V˙E/V˙CO2 slope (p<0.001), peak V˙O2 % (p=.001), QRS duration (p=.001) and age (p=0.046) independently predicted event free survival. V˙E/V˙CO2 slope ≥ 31.0, peak V˙O2 % ≤ 65% and QRS duration ≥ 170 ms were the cut-off points with best sensitivity and specificity to detect an unfavorable outcome. CONCLUSIONS: CPET is an important predictive tool that may assist in the risk stratification of patients with ToF. Subjects with a poor exercise capacity in addition to a prolonged QRS duration have a substantially increased risk for death or sustained ventricular tachycardia, as well as for cardiac-related hospitalizations.

3D-manufactured patient-specific models of congenital heart defects for communication in clinical practice: feasibility and acceptability.

OBJECTIVES: To assess the communication potential of three-dimensional (3D) patient-specific models of congenital heart defects and their acceptability in clinical practice for cardiology consultations. DESIGN: This was a questionnaire-based study in which participants were randomised into two groups: the 'model group' received a 3D model of the cardiac lesion(s) being discussed during their appointment, while the 'control group' had a routine visit. SETTING: Outpatient clinic, cardiology follow-up visits. PARTICIPANTS: 103 parents of children with congenital heart disease were recruited (parental age: 43±8 years; patient age: 12±6 years). In order to have a 3D model made, patients needed to have a recent cardiac MRI examination; this was the crucial inclusion criterion. INTERVENTIONS: Questionnaires were administered to the participants before and after the visits and an additional questionnaire was administered to the attending cardiologist. MAIN OUTCOME MEASURES: Rating (1-10) for the liking of the 3D model, its usefulness and the clarity of the explanation received were recorded, as well as rating (1-10) of the parental understanding and their engagement according to the cardiologist. Furthermore, parental knowledge was assessed by asking them to mark diagrams, tick keywords and provide free text answers. The duration of consultations was recorded and parent feedback collected. RESULTS: Parents and cardiologists both found the models to be very useful and helpful in engaging the parents in discussing congenital heart defects. Parental knowledge was not associated with their level of education (p=0.2) and did not improve following their visit. Consultations involving 3D models lasted on average 5 min longer (p=0.02). CONCLUSIONS: Patient-specific models can enhance engagement with parents and improve communication between cardiologists and parents, potentially impacting on parent and patient psychological adjustment following treatment. However, in the short-term, parental understanding of their child's condition did not improve.

Impact of percutaneous pulmonary valve implantation for right ventricular outflow tract dysfunction on exercise recovery kinetics.

The recovery of cardiopulmonary variables from peak exercise in patients with pulmonary stenosis (PS) or regurgitation (PR) is delayed, but the impact of treating PS or PR on exercise recovery kinetics is unknown. 43 patients (median age 14 years) with PS (n = 23) or PR (n = 20) after repair of congenital heart disease underwent successful percutaneous pulmonary valve implantation (PPVI). Cardiopulmonary exercise tests (CPET) were performed both before and within 1 month after PPVI. Apart from peak oxygen uptake (VO2), the constant decay of VO2, CO2 output (VCO2), minute ventilation (VE), and heart rate (HR) and oxygen pulse were calculated for the first minute of recovery as the first-degree slope of a single linear relation. PPVI led to a significant improvement in NYHA functional class in the PS and PR groups (p<0.001 and p=0.0015, respectively). On CPET, peak VO2 improved post-PPVI only in the PS (25.6 ± 6.2 vs. 27.8 ± 7.9 ml/kg/min; p = 0.01) but not PR group (29.0 ± 9.8 vs. 28.6 ± 8.9 ml/kg/min; p = 0.6). However, VO2 slope improved in the PS (0.40 ± 0.23 vs. 0.65 ± 0.27, p < 0.001) as well as in the PR group (0.56 ± 0.37 vs. 0.67 ± 0.37, p = 0.003) as did VCO2 slope (0.39 ± 0.2 vs. 0.55 ± 0.24, p = 0.002 and 0.42 ± 0.33 vs. 0.53 ± 0.35, p = 0.02: for the PS and PR groups, respectively). The VE and HR slopes did not change after PPVI. Despite the lack of improvement in exercise capacity in the PR group, treatment of PS and PR by PPVI induces significant and similar improvements in the ability of recovering from maximal exercise in the 2 groups.

Ventriculovascular interactions late after atrial and arterial repair of transposition of the great arteries.

OBJECTIVE: The aim of this study was to compare atrial switch and arterial switch operations for the repair of transposition of the great arteries (TGA), assessing cardiac function and ventriculoarterial (VA) coupling based on cardiac magnetic resonance (CMR) data. Using CMR-derived wave intensity analysis, this study provides a noninvasive comparison of the 2 systemic ventricles and evaluates the subclinical hemodynamic burden of these operations. METHODS: Fifty-four patients (18 controls, 18 atrial switches, 18 arterial switches) were studied. Dimensional and functional data, including the ejection fraction (EF) and end-diastolic volume, were derived from CMR, as well as aortic distensibility. Wave intensity was computed from CMR according to a formulation based on changes in area and velocity, and the peaks of the 2 major systolic waves (forward compression wave [FCW], and forward expansion wave [FEW]) were measured as indicators of ventricular function. RESULTS: Both switches exhibited significantly increased end-diastolic volume and enlarged aortic root areas, and atrial switches were also characterized by significantly lower EF. Patients with TGA presented stiffer ascending aortas, particularly those repaired with an arterial switch. Both FCW and FEW were significantly lower in both TGA cohorts than the controls, suggesting compromised VA coupling, likely a result of increased impedance caused by the stiffer ascending aorta. A significant difference between switch type was noticed in terms of the FEW peak, which was lower in the atrial switch group. CONCLUSIONS: These data highlight reduced aortic distensibility and abnormal VA coupling in repaired TGA. An intraoperational difference was noted in terms of EF and peak FEW, likely reflecting the different nature of the subaortic ventricle.

3D morphometric analysis of the arterial switch operation using in vivo MRI data.

The arterial switch operation (ASO) is widely used nowadays as the surgical strategy of choice to repair transposition of the great arteries (TGA). Residual morphological and geometrical abnormalities of the aorta, pulmonary arteries and coronary arteries, however, have not been fully studied in a three-dimensional (3D) domain. These morphometric complications might have implications on long-term outcomes of ASO patients, hence the need to explore them in detail and study them with reference to healthy controls of comparable age and body surface area. These anatomical characteristics were examined using 3D patient-specific anatomical models reconstructed from cardiovascular magnetic resonance (CMR) images of 20 ASO patients (mean age 14.4 ± 2.4 years, 16 males and 4 females) compared with healthy controls (mean age 15.2 ± 2.0 years, 17 males and 3 females). It was found that the aorta, pulmonary arteries and re-implanted coronary arteries of ASO patients were significantly different morphologically and geometrically to those of healthy controls. In particular, the aortic root was dilated, with abnormal 3D angulation and additional acute angulation of the curvature of the aortic arch in the ASO group compared with controls. This could theoretically impinge on aortic flow profiles and physiological stresses, which can act as a primer for the development of early atherosclerotic disease in the ASO population.