Comparison of Four-Dimensional Flow MRI, Two-Dimensional Phase-Contrast MRI and Echocardiography in Transposition of the Great Arteries

Pulmonary artery (PA) stenosis is a common complication after the arterial switch operation (ASO) for transposition of the great arteries (TGA). Four-dimensional flow (4D flow) CMR provides the ability to quantify flow within an entire volume instead of a single plane. The aim of this study was to compare PA maximum velocities and stroke volumes between 4D flow CMR, two-dimensional phase-contrast (2D PCMR) and echocardiography. A prospective study including TGA patients after ASO was performed between December 2018 and October 2020. All patients underwent echocardiography and CMR, including 2D PCMR and 4D flow CMR. Maximum velocities and stroke volumes were measured in the main, right, and left PA (MPA, LPA, and RPA, respectively). A total of 39 patients aged 20 ± 8 years were included. Maximum velocities in the MPA, LPA, and RPA measured by 4D flow CMR were significantly higher compared to 2D PCMR (p < 0.001 for all). PA assessment by echocardiography was not possible in the majority of patients. 4D flow CMR maximum velocity measurements were consistently higher than those by 2D PCMR with a mean difference of 65 cm/s for the MPA, and 77 cm/s for both the RPA and LPA. Stroke volumes showed good agreement between 4D flow CMR and 2D PCMR. Maximum velocities in the PAs after ASO for TGA are consistently lower by 2D PCMR, while echocardiography only allows for PA assessment in a minority of cases. Stroke volumes showed good agreement between 4D flow CMR and 2D PCMR.

30 Years' Experience in Percutaneous Pulmonary Artery Interventions in Transposition of the Great Arteries

Background

Pulmonary artery (PA) stenosis is common after arterial switch operation (ASO) for transposition of the great arteries (TGA). Differences between balloon angioplasty (BA) and stents on right ventricular (RV) and PA pressures are not well studied.

Objectives

The purpose of this study was to analyze percutaneous PA interventions' frequency after ASO, complications, and the effects of BA and stents on RV and PA pressures.

Methods

All TGA patients with ASO between 1977 and 2022 in 2 Dutch congenital heart centers were included in this multicenter retrospective study. Peri-operative ASO characteristics and pre-intervention and post-intervention invasive and echocardiographic data were analyzed.

Results

ASO was performed in 960 TGA patients, of which 888 survived 30 days and had complete follow-up. Seventy-seven (9%) underwent percutaneous PA interventions. Taussig-Bing anomaly (OR: 2.8; 95% CI: 1.228-6.168; P = 0.014), ASO time era 1990 to 1999 (OR: 4.7; 95% CI: 1.762-12.780; P = 0.002), and 2000 to 2009 (OR: 4.3; 95% CI: 1.618-11.330; P = 0.003) were independently associated with percutaneous PA interventions after ASO. Invasive post-interventional pressures and gradients were lower after stent implantation compared to BA (RV pressure: 47 ± 14 vs 58 ± 11; right PA-PA gradient: 11 ± 11 vs 25 ± 12, P < 0.05; RV/left ventricle pressure ratio: 0.4 ± 0.1 vs 0.6 ± 0.2, P < 0.001). Of the patients with unilateral PA stenosis (left PA: 41%, right PA: 59%), 77% showed increased RV pressure (>30 mm Hg) and RV/left ventricle pressure ratio improved post-intervention (0.5 ± 0.2 vs 0.6 ± 0.2, P < 0.05). Seventeen complications, most minor, were reported (13%). Two post-procedural deaths were reported.

Conclusions

Percutaneous PA interventions are common after ASO and can be performed safely but caution for serious complications is warranted. Unilateral PA stenosis can impact RV pressures. Stents may be more successful at treating PA stenosis compared to BA.

The effects of percutaneous branch pulmonary artery interventions in biventricular congenital heart disease: study protocol for a randomized controlled Dutch multicenter interventional trial

BACKGROUND

Branch pulmonary artery (PA) stenosis is one of the most common indications for percutaneous interventions in patients with transposition of the great arteries (TGA), tetralogy of Fallot (ToF), and truncus arteriosus (TA). However, the effects of percutaneous branch PA interventions on exercise capacity remains largely unknown. In addition, there is no consensus about the optimal timing of the intervention for asymptomatic patients according to international guidelines. This trial aims to identify the effects of percutaneous interventions for branch PA stenosis on exercise capacity in patients with TGA, ToF, and TA. In addition, it aims to assess the effects on RV function and to define early markers for RV adaptation and RV dysfunction to improve timing of these interventions.

METHODS

This is a randomized multicenter interventional trial. TGA, ToF, and TA patients ≥ 8 years with a class IIa indication for percutaneous branch PA intervention according to international guidelines are eligible to participate. Patients will be randomized into the intervention group or the control group (conservative management for 6 months). All patients will undergo transthoracic echocardiography, cardiac magnetic resonance (CMR) imaging, and cardiopulmonary exercise testing at baseline, 6 months, and 2-4 years follow-up. Quality of life (QoL) questionnaires will be obtained at baseline, 2 weeks post intervention or a similar range for the control group, and 6 months follow-up. The primary outcome is exercise capacity expressed as maximum oxygen uptake (peak VO2 as percentage of predicted). A total of 56 patients (intervention group n = 28, control group n = 28) is required to demonstrate a 14% increase in maximum oxygen uptake (peak VO2 as percentage of predicted) in the interventional group compared to the control group (power 80%, overall type 1 error controlled at 5%). Secondary outcomes include various parameters for RV systolic function, RV functionality, RV remodeling, procedural success, complications, lung perfusion, and QoL.

DISCUSSION

This trial will investigate the effects of percutaneous branch PA interventions on exercise capacity in patients with TGA, ToF, and TA and will identify early markers for RV adaptation and RV dysfunction to improve timing of the interventions.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05809310. Registered on March 15, 2023.

Excellent Survival With a Focus on Pulmonary Artery Reinterventions After the Arterial Switch Operation

Background: We sought to evaluate the outcomes in patients who underwent the arterial switch operation (ASO) over a 20-year period at a single institution. Methods: The current study is a retrospective review of 180 consecutive patients who underwent the ASO for biventricular surgical correction of dextro-transposition of the great arteries (d-TGA) between 2002 and 2022. Results: Among 180 patients, 121 had TGA-intact ventricular septum, 47 had TGA-ventricular septal defect and 12 had Taussig-Bing Anomaly (TBA). The median follow-up time was 6.7 years (interquartile range: 3.9-8.7 years). There were five early (2.8%) and one late (0.6%) mortality. Survival was 96.6% at one year and beyond. Reoperations were performed in 31 patients (17%). Taussig Bing Anomaly was found to increase the risk of reoperation by 17 times (P < .0001). A total of 37 (21%) patients underwent 53 reinterventions (14 surgical procedures, 39 catheter interventions) specifically addressing pulmonary artery (PA) stenosis. Freedom from PA reintervention was 97%, 87%, 70%, and 55% at 1, 5, 10, and 15 years, respectively. By bivariable analysis, TBA (P = .003, odds ratio [OR]: 6.4, 95% confidence interval [CI]: 1.9-21.7), mild PA stenosis at discharge (P ≤ .001, OR: 6.1, 95% CI: 2.7-13.6), and moderate or severe PA stenosis at discharge (P ≤ .001, OR: 12.7, 95% CI: 5-32.2) were identified as predictors of reintervention on PA. In the last follow-up of 174 survivors, 24 patients (14%) had moderate or greater PA stenosis, two (1%) had moderate neoaortic valve regurgitation, and 168 were New York Heart Association status I. Conclusions: Our results demonstrated excellent survival and functional status following the ASO for d-TGA; however, patients remain subject to frequent reinterventions especially on the pulmonary arteries.

Pulmonary, aorta, and coronary arteries post-arterial switch in transposition of great arteries: intermediate-term surveillance utilizing conventional echocardiography and cardiac multislice computed tomography

BACKGROUND

Arterial switch operation (ASO) is the standard surgical choice for D-transposition of great arteries (D-TGA). However, the implications of ASO on pulmonaries, coronaries, and aorta have not been adequately investigated. The current study evaluates arterial morphologic changes post-ASO at intermediate-term surveillance.

METHODS

From May 2021 to May 2022, patients with D-TGA who underwent ASO for more than six months were recruited. Preoperative and operative data were collected. Patients were assessed using echocardiography (ECHO) and multislice CT angiography (MSCT) to evaluate pulmonary, coronary, and aortic arterial anatomy.

RESULTS

Twenty patients were included with median age of 11 (10-23.25) days at ASO and 14 (7.25-32.75) months on last follow-up. Neo-aortic regurgitation was detected in 12(60%) and neo-pulmonary regurgitation in 3 (15%). Using ECHO, complete evaluation of pulmonary arteries (PAs) was not achieved in 35% and incomplete coronaries assessment in 40% of cases. No stenosis was detected in coronaries using MSCT, although coronary anomalies were found in 9/20 (45%). Dilated Aortic annulus was detected in 16/20 (80%), dilated aortic root in 18/20 (90%), and dilated sinotubular junction in 70%. Right PA stenosis was diagnosed in 10/20 (50%) and left PA(LPA) stenosis in 7/20 (35%). Although Z-score of PAs did not correlate with aortic data, LPA bending angle was positively correlated to neo-aortic root diameter and Z-score (rho = 0.65,p = 0.016; rho = 0.69,p = 0.01), respectively.

CONCLUSION

Echocardiography alone is not a conclusive surveillance tool for detecting late post-ASO anatomic changes in D-TGA patients. Cardiac MSCT should be considered for comprehensive evaluation on the intermediate-term follow-up post-ASO to accurately track morphologic abnormalities in the aorta, pulmonary, and coronary arteries.

Neoaortic Regurgitation Detected by Echocardiography After Arterial Switch Operation: A Systematic Review and Meta-Analysis

Background

Neoaortic root dilatation (NeoARD) and neoaortic regurgitation (NeoAR) are common sequelae following the arterial switch operation (ASO) for transposition of the great arteries.

Objectives

The authors aimed to estimate the cumulative incidence of NeoAR, assess whether larger neoaortic root dimensions were associated with NeoAR, and evaluate factors associated with the development of NeoAR during long-term follow-up.

Methods

Electronic databases were systematically searched for articles that assessed NeoAR and NeoARD after ASO, published before November 2022. The primary outcome was NeoAR, classified based on severity categories (trace, mild, moderate, and severe). Cumulative incidence was estimated from Kaplan-Meier curves, neoaortic root dimensions using Z-scores, and risk factors were evaluated using random-effects meta-analysis.

Results

Thirty publications, comprising a total of 6,169 patients, were included in this review. Pooled estimated cumulative incidence of ≥mild NeoAR and ≥moderate NeoAR at 30-year follow-up were 67.5% and 21.4%, respectively. At last follow-up, neoaortic Z-scores were larger at the annulus (mean difference [MD]: 1.17, 95% CI: 0.52-1.82, P < 0.001; MD: 1.38, 95% CI: 0.46-2.30, P = 0.003) and root (MD: 1.83, 95% CI: 1.16-2.49, P < 0.001; MD: 1.84, 95% CI: 1.07-2.60, P < 0.001) in patients with ≥mild and ≥moderate NeoAR, respectively, compared to those without NeoAR. Risk factors for the development of any NeoAR included prior pulmonary artery banding, presence of a ventricular septal defect, aorto-pulmonary mismatch, a bicuspid pulmonary valve, and NeoAR at discharge.

Conclusions

The risks of NeoARD and NeoAR increase over time following ASO surgery. Identified risk factors for NeoAR may alert the clinician that closer follow-up is needed. (Risk factors for neoaortic valve regurgitation after arterial switch operation: a meta-analysis; CRD42022373214).

Multimodality Imaging in Management of Adults with Dextro-Transposition of the Great Arteries Post Arterial Switch Operation

•Echo is an essential tool for monitoring long-term complications of D-TGA with ASO. •Multimodality imaging is complementary to echo in the assessment of complications. •4D flow CMR can assess supravalvular PS post ASO. •Branch pulmonary arteries after LeCompte maneuver can be challenging to image.

The effects of percutaneous branch pulmonary artery interventions on exercise capacity, lung perfusion, and right ventricular function in biventricular CHD: a systematic review

BACKGROUND

Branch pulmonary artery stenosis is common after surgical repair in patients with biventricular CHD and often requires reinterventions. However, (long-term) effects of percutaneous branch pulmonary artery interventions on exercise capacity, right ventricular function, and lung perfusion remain unclear. This review describes the (long-term) effects of percutaneous branch pulmonary artery interventions on exercise capacity, right ventricular function, and lung perfusion following PRISMA guidelines.

METHODS

We performed a systematic search in PubMed, Embase, and Cochrane including studies about right ventricular function, exercise capacity, and lung perfusion after percutaneous branch pulmonary artery interventions. Study selection, data extraction, and quality assessment were performed by two researchers independently.

RESULTS

In total, 7 eligible studies with low (n = 2) and moderate (n = 5) risk of bias with in total 330 patients reported on right ventricular function (n = 1), exercise capacity (n = 2), and lung perfusion (n = 7). Exercise capacity and lung perfusion seem to improve after a percutaneous intervention for branch pulmonary artery stenosis. No conclusions about right ventricular function or remodelling, differences between balloon and stent angioplasty or specific CHD populations could be made.

CONCLUSION

Although pulmonary artery interventions are frequently performed in biventricular CHD, data on relevant outcome parameters such as exercise capacity, lung perfusion, and right ventricular function are largely lacking. An increase in exercise capacity and improvement of lung perfusion to the affected lung has been described in case of mild to more severe pulmonary artery stenosis during relatively short follow-up. However, there is need for future studies to evaluate the effect of pulmonary artery interventions in various CHD populations.

Cardiac Catheterization Interventions in the Right Ventricular Outflow Tract and Branch Pulmonary Arteries Following the Arterial Switch Operation

The arterial switch operation for d-transposition of the great arteries achieves anatomic repair but creates the potential for right ventricular outflow tract obstruction as a result of the LeCompte maneuver. The resultant right ventricular hypertension is generally well tolerated but a select group are referred for cardiac catheterization. The outcomes of these catheterizations have not been well described. The objective of this study was to describe the degree and nature of right ventricular outflow tract obstruction found during cardiac catheterization among patients following the arterial switch operation as well as determine the rate of intervention and assess the acute impact of any catheter intervention undertaken. We conducted a retrospective study of patients after arterial switch operation with the LeCompte maneuver and subsequent right heart catheterization. Descriptive statistics were reported, and paired sample t tests were used for analysis. 544 children had an arterial switch operation, of which 110 children (20%) had a cardiac catheterization procedure after surgery and 11% had a right heart catheterization. Of the right heart catheterizations, 90% had an intervention (balloon and/or stent). In the interventional group, the right ventricle to systemic pressure ratio decreased modestly, from 2/3 to half systemic, after balloon dilation and/or stent placement (p < 0.01). No serious complications were observed.

[Cardiac MRI of congenital heart disease : From fetus to adult]

BACKGROUND

Cardiac magnetic resonance imaging (MRI) is an important diagnostic tool for initial diagnostic workup and follow-up of patients with congenital heart disease (CHD) of different age groups.

OBJECTIVES

This review provides an overview of clinically applied MRI sequences for the assessment of CHD, highlights technical developments, and demonstrates key aspects of reporting in specific heart defects.

MATERIALS AND METHODS

Presentation of epidemiologic data, summary of studies on MRI sequences and their clinical application, and demonstration of clinical examples.

RESULTS

The broad spectrum of congenital heart defects requires the use of various sequences, which can be modified depending on patient age or treatment status. Cine imaging can be used to assess cardiac function and volumes, phase contrast flow measurements allow for the assessment of vessel hemodynamics, and various techniques of MR angiography allow visualization of the thoracic vessels with high spatiotemporal resolution. New developments allow high-resolution vascular imaging without the need for contrast agents, assessment of additional hemodynamic parameters, or fetal cardiac MRI.

CONCLUSION

Cardiac MRI can be employed in children as well as in adults with CHD. By using different sequences and considering the treatment status and surgery-related complications, the vast majority of clinical questions can be answered.

Quantification of Pulmonary Artery Configuration after the Arterial Switch Operation: A Pilot Study

Background: The arterial switch operation (ASO) is the preferred treatment for d-transposition of the great arteries (TGA). Freedom from reintervention is mainly determined by the performance of the arterial outflow tracts, with variable incidence of pulmonary artery stenosis (PAS), possibly related to aspects of surgical technique. This pilot study attempts to describe pulmonary artery (PA) configuration through several measurements using three-dimensional data from cardiac magnetic resonance (CMR) imaging and assesses whether PA configuration is associated with PAS. Methods: A retrospective, single-centre analysis of paediatric patients undergoing CMR after ASO. The geometry of the pulmonary arteries was compared between patients with and without PAS as judged by the CMR report. Results: Among all patients (n = 612) after ASO, 45 patients underwent CMR at a median age of 10 years (3.5–13). Twenty-two (57.9%) had PAS, categorized as mild (n = 1), moderate (n = 19) or severe (n = 2). Eighteen had stenosis on PA branches. Four had MPA stenosis. Comparison between groups with and without PAS revealed no significant differences in neo-aortic to pulmonary angle, MPA to LPA/RPA angle, or bifurcation angle. There was a significant difference in cranial displacement, with more cranial displacement in the group without PAS. However, this group was older, 10.8 (7.3–14.3) years compared to those with PAS, 6.8 (1.5–12.1). Conclusions: The spectrum of PAS after ASO is heterogenous. This study shows the feasibility of measuring PA configuration in three planes on CMR. There is no correlation between PA configuration and PAS. Therefore, other mechanisms are probably responsible for the occurrence of PAS, rather than the configuration on itself. Further multicentric studies are warranted to confirm the suggested measuring method and assessing the associations with PAS, to eventually advise surgical methodology.

Nuclear Imaging in Pediatric Cardiology: Principles and Applications

Nuclear imaging plays a unique role within diagnostic imaging since it focuses on cellular and molecular processes. Using different radiotracers and detection techniques such as the single photon emission scintigraphy or the positron emission tomography, specific parameters can be assessed: myocardial perfusion and viability, pulmonary perfusion, ventricular function, flow and shunt quantification, and detection of inflammatory processes. In pediatric and congenital cardiology, nuclear imaging can add complementary information compared to other imaging modalities such as echocardiography or magnetic resonance imaging. In this state-of-the-art paper, we appraise the different techniques in pediatric nuclear imaging, evaluate their advantages and disadvantages, and discuss the current clinical applications.

Canadian Cardiovascular Society 2022 Guidelines for Cardiovascular Interventions in Adults With Congenital Heart Disease

Interventions in adults with congenital heart disease (ACHD) focus on surgical and percutaneous interventions in light of rapidly evolving ACHD clinical practice. To bring rigour to our process and amplify the cumulative nature of evidence ACHD care we used the ADAPTE process; we systematically adjudicated, updated, and adapted existing guidelines by Canadian, American, and European cardiac societies from 2010 to 2020. We applied this to interventions related to right and left ventricular outflow obstruction, tetralogy of Fallot, coarctation, aortopathy associated with bicuspid aortic valve, atrioventricular canal defects, Ebstein anomaly, complete and congenitally corrected transposition, and patients with the Fontan operation. In addition to tables indexed to evidence, clinical flow diagrams are included for each lesion to facilitate a practical approach to clinical decision-making. Excluded are recommendations for pacemakers, defibrillators, and arrhythmia-directed interventions covered in separate designated documents. Similarly, where overlap occurs with other guidelines for valvular interventions, reference is made to parallel publications. There is a paucity of high-level quality of evidence in the form of randomized clinical trials to support guidelines in ACHD. We accounted for this in the wording of the strength of recommendations put forth by our national and international experts. As data grow on long-term follow-up, we expect that the evidence driving clinical practice will become increasingly granular. These recommendations are meant to be used to guide dialogue between clinicians, interventional cardiologists, surgeons, and patients making complex decisions relative to ACHD interventions.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the use of cardiovascular magnetic resonance in pediatric congenital and acquired heart disease : Endorsed by The American Heart Association

Cardiovascular magnetic resonance (CMR) has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of CMR in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of CMR in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the Use of Cardiac Magnetic Resonance in Pediatric Congenital and Acquired Heart Disease: Endorsed by The American Heart Association

Cardiovascular magnetic resonance has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of cardiovascular magnetic resonance in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of cardiovascular magnetic resonance in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Right ventricular afterload in repaired D-TGA is associated with inefficient flow patterns, rather than stenosis alone

Treatment of D- transposition of great arteries (DTGA) involves the Arterial Switch Operation (ASO), which can create PA branch stenosis (PABS) and alter PA blood flow energetics. This altered PA flow may contribute to elevated right ventricular (RV) afterload more significantly than stenosis alone. Our aim was to correlate RV afterload and PA flow characteristics using 4D flow cardiac magnetic resonance (CMR) imaging of a mock circulatory system (MCS) incorporating 3D printed replicas. CMR imaging and clinical characteristics were analyzed from 22 ASO patients (age 11.9 ± 8.7 years, 68% male). Segmentation was performed to create 3D printed PA replicas that were mounted in an MRI-compatible MCS. Pressure drop across the PA replica was recorded and 4D flow CMR acquisitions were analyzed for blood flow inefficiency (energy loss, vorticity). In post-ASO patients, there is no difference in RV mass (p = 0.07), nor RV systolic pressure (p = 0.26) in the presence or absence of PABS. 4D flow analysis of MCS shows energy loss is correlated to RV mass (p = 0.01, r = 0.67) and MCS pressure differential (p = 0.02, r = 0.57). Receiver operating characteristic curve shows energy loss detects elevated RV mass above 30 g/m² (p = 0.02, AUC 0.88) while index of PA dimensions (Nakata) does not (p = 0.09, AUC 0.79). PABS alone does not account for differences in RV mass or afterload in post-ASO patients. In MCS simulations, energy loss is correlated with both RV mass and PA pressure, and can moderately detect elevated RV mass. Inefficient PA flow may be an important predictor of RV afterload in this population.

Characterization of Flow Dynamics in the Pulmonary Bifurcation of Patients With Repaired Tetralogy of Fallot: A Computational Approach

The hemodynamic environment of the pulmonary bifurcation is of great importance for adult patients with repaired tetralogy of Fallot (rTOF) due to possible complications in the pulmonary valve and narrowing of the left pulmonary artery (LPA). The aim of this study was to computationally investigate the effect of geometrical variability and flow split on blood flow characteristics in the pulmonary trunk of patient-specific models. Data from a cohort of seven patients was used retrospectively and the pulmonary hemodynamics was investigated using averaged and MRI-derived patient-specific boundary conditions on the individualized models, as well as a statistical mean geometry. Geometrical analysis showed that curvature and tortuosity are higher in the LPA branch, compared to the right pulmonary artery (RPA), resulting in complex flow patterns in the LPA. The computational analysis also demonstrated high time-averaged wall shear stress (TAWSS) at the outer wall of the LPA and the wall of the RPA proximal to the junction. Similar TAWSS patterns were observed for averaged boundary conditions, except for a significantly modified flow split assigned at the outlets. Overall, this study enhances our understanding about the flow development in the pulmonary bifurcation of rTOF patients and associates some morphological characteristics with hemodynamic parameters, highlighting the importance of patient-specificity in the models. To confirm these findings, further studies are required with a bigger cohort of patients.

Reference Values for Ventricular Volumes and Pulmonary Artery Dimensions in Pediatric Patients with Transposition of the Great Arteries After Arterial Switch Operation

BACKGROUND

Pulmonary artery (PA) anatomy in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) with Lecompte manoeuvre is different compared to healthy subjects, and stenoses of the PA are common. Magnetic resonance imaging (MRI) is an excellent imaging modality to assess PA anatomy in TGA patients. However, disease-specific reference values for PA size are scarce.

PURPOSE

To establish disease-specific reference ranges for PA dimensions and for biventricular volumes and mass.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 69 pediatric patients with TGA after ASO (median age 12.6 years; range 5-17.8 years; 13 females and 56 males).

FIELD STRENGTH/SEQUENCE

3.0 T, steady-state free precession (SSFP) and gradient echo cine sequences and four-dimensional time-resolved magnetic resonance angiography with keyhole.

ASSESSMENT

Right and left PA (RPA, LPA) were each measured at three locations during its course around the aorta. Ventricular volumes, mass, and ejection fraction were measured from a stack of short axis cine images.

STATISTICAL TESTS

The lambda-mu-sigma (LMS) method of Cole and Green, univariate and multivariate linear models, and t-test.

RESULTS

Centile graphs and tables for PA dimensions, biventricular volumes, mass, and ejection fraction were created. Univariate linear analysis showed significant associations (P < 0.05) between body surface area (BSA), height, and weight with systolic MPA and RPA diameter. In multivariate linear analysis, only BSA remained a strong predictor for main PA and RPA diameters. For biventricular volumes, the univariate linear model revealed a strong influence of BSA, height, weight, and age (all P < 0.05). On multivariate linear analysis, only body height remained associated.

DATA CONCLUSION

Uni- and multivariate linear analyses showed a strong association between BSA and PA diameters, as well as between height and biventricular volumes, and therefore, centile tables and graphs are presented accordingly. Our data may improve MR image interpretation and may serve as a reference in future studies.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY STAGE: 2.

Management considerations in the adult with surgically modified d-transposition of the great arteries

Dextro-transposition of the great arteries (D-TGA) has undergone a significant evolution in surgical repair, leading to survivors with vastly different postsurgical anatomy which in turn guides their long-term cardiovascular morbidity and mortality. Atrial switch repair survivors are limited by a right ventricle in the systemic position, arrhythmia and atrial baffles prone to obstruction or leak. Functional assessment of the systemic right ventricle is complex, requiring multimodality imaging to include specialised echocardiography and cross-sectional imaging (MRI and CT). In the current era, most neonates undergo the arterial switch operation with increasing understanding of near-term and long-term outcomes specific to their cardiac anatomy. Long-term observations of the Lecompte manoeuvre or coronary stenoses following transfer continue, with evolving understanding to improve surveillance. Ultimately, an understanding of postsurgical anatomy, specialised imaging techniques and interventional and electrophysiological procedures is essential to comprehensive care of D-TGA survivors.

Long-term outcomes of the arterial switch operation

OBJECTIVES

The arterial switch operation (ASO) has excellent early outcomes in the modern era. We sought to determine the long-term outcomes in patients who underwent an ASO at a single institution.

METHODS

Patients who underwent an ASO between 1983 and 2015 were identified from the hospital database and retrospectively reviewed using hospital records.

RESULTS

From 1983 to 2015, 844 patients with a biventricular circulation underwent an ASO. There were 28 (3.3%, 28/844) early deaths. Follow-up was available for 94% (729/774) of local patients after hospital discharge. Median follow-up was 15 years (interquartile range, 8-20 years). There were 187 (26%, 187/729) patients with more than 20 years of follow-up and 95 (13%, 95/729) patients with more than 25 years of follow-up. Overall survival was 95% (95% confidence interval [CI], 94%-97%) at 10 and 25 years after the ASO. At 25 years after ASO, freedom from overall reintervention was 77% (95% CI, 73%-81%), freedom from reoperation on the neoaortic root or neoaortic valve was 92% (95% CI, 88%-95%), and freedom from coronary reoperation was 99% (95% CI, 98%-99.7%). Left ventricular (LV) systolic function was normal in 595 of 609 (98%) of patients who had LV function quantified at latest follow-up. Of the 95 patients with more than 25 years of follow-up after ASO, 6 (6.3%) had at least moderate neoaortic valve regurgitation (AR) and 8 (8.4%) had undergone replacement of the neoaortic valve.

CONCLUSIONS

Overall, survivors of ASO have excellent late survival and normal LV systolic function into adult life. However, AR and reoperation on the neoaortic valve remains an issue for older patients.

Role of Computed Tomography in Postoperative Follow-up of Arterial Switch Operation

An arterial switch operation (ASO) is the standard treatment for infants and children born with D-loop transposition of the great arteries. During the ASO, the great vessels are transected from the native roots, switched and anastomosed with the opposite roots. This is accompanied by the relocation of the pulmonary artery anterior to the aorta by using the LeCompte maneuver and the translocation of coronary arteries to the neo-aorta. ASO has led to improved overall survival, and postoperative mortality is rare. Despite the improved outcomes, several postoperative sequelae may occur, and therefore patients require long-term follow-up. Computed tomography (CT) has emerged as a robust imaging modality in pre and postoperative evaluation of a variety of congenital heart disorders including ASO. Unlike echocardiography and cardiovascular magnetic resonance, CT is not hindered by a poor acoustic window, metallic devices or the need for sedation or general anesthesia. CT with advanced three-dimensional postprocessing techniques, high pitch scanning, wider detector system, electrocardiogram-dependent modulation and dose-reduction strategies is invaluable in assessing the postoperative complications after ASO.

CT and MRI for Repaired Complex Adult Congenital Heart Diseases

An increasing number of adult congenital heart disease (ACHD) patients continue to require life-long diagnostic imaging surveillance using cardiac CT and MRI. These patients typically exhibit a large spectrum of unique anatomical and functional changes resulting from either single- or multi-stage palliation and surgical correction. Radiologists involved in the diagnostic task of monitoring treatment effects and detecting potential complications should be familiar with common cardiac CT and MRI findings observed in patients with repaired complex ACHD. This review article highlights the contemporary role of CT and MRI in three commonly encountered repaired ACHD: repaired tetralogy of Fallot, transposition of the great arteries after arterial switch operation, and functional single ventricle after Fontan operation.

The poor long-term outcomes of owl's eye pulmonary reconstruction technique after arterial switch operation

OBJECTIVES

This study aims to compare the early- and long-term outcomes of patients who undergo owl's eye pulmonary artery (PA) reconstruction to those of patients who undergo conventional PA reconstruction.

METHODS

From January 2016 to January 2017, 64 consecutive patients underwent an arterial switch operation. The patients were divided into 2 groups in terms of neo-PA reconstruction method: 30 patients who underwent neo-PA reconstruction by owl's eye technique were defined as group 1 and 34 patients who underwent neo-PA reconstruction by the conventional approach were defined as group 2. In the final model, after propensity matching, 23 patients from each group with similar propensity scores were included in the study.

RESULTS

There was no significant difference between the groups regarding patient characteristics and operative findings. In the early period, the duration of intensive care unit and hospital stays and the rate of mild neo-pulmonary stenosis (neo-PS) were significantly higher in the owl's eye group (P = 0.04, 0.04 and 0.03). In the late period, the rate of severe neo-PS and reintervention was significantly higher in the owl's eye group (P = 0.02 and 0.04). Furthermore, the rates of 3-year freedom from pulmonary reintervention and freedom from moderate-severe neo-PS were significantly lower in group 1 (P = 0.04). In addition, the owl's eye reconstruction was the only factor independently related to moderate-severe neo-PS in the long term (hazard ratios = 11.2, P = 0.02).

CONCLUSIONS

We have abandoned the owl's eye method for neo-PA reconstruction of the neo-PA because of serious complications. According to our series and the literature, reconstruction of the neo-PA with an oversized, pantaloon-shaped fresh autologous pericardial patch is still superior to the other techniques.

Neopulmonary Outflow Tract Obstruction Assessment by 4D Flow MRI in Adults With Transposition of the Great Arteries After Arterial Switch Operation

BACKGROUND

The main complication in adult patients with transposition of the great arteries (TGA) treated by an arterial switch operation (ASO) is neopulmonary outflow tract stenosis (NPOTS). However, pulmonary flow velocity measurements cannot always be performed with transthoracic echocardiography (TTE) due to complex anatomical features. 4D flow MRI allows detection, quantification, and location of the obstruction site along the NPOTS.

PURPOSE AND HYPOTHESIS

To investigate the accuracy of 4D flow for the diagnosis of NPOTS in adults with TGA corrected by ASO.

STUDY TYPE

Prospective.

POPULATION

Thirty-three adult patients with TGA treated by ASO (19 men, mean age 25.5 years old).

FIELD STRENGTH/SEQUENCE

Accelerated 4D flow research sequence at 3T.

ASSESSMENT

Maximum NPOTS velocities on TTE and 4D flow MRI done the same day.

STATISTICAL TESTS

Pearson correlation coefficient, paired t-test, and Bland-Altman analysis were used to investigate the relationship between TTE and MRI data.

RESULTS

In 16 patients (48.5%), evaluation of NPOTS anatomy was not obtained by TTE, while it was always possible by 4D flow. Peak flow velocity (PV) measurements in Doppler and 4D flow were highly correlated (r = 0.78; P < 0.001). PV >350 cm.s^-1 was detected in only one patient (3%) by TTE vs. five patients (15%) by 4D flow. Moreover, a high correlation was found between PV and the right ventricle (RV) mass index to body surface area when using 4D flow (r = 0.63; P < 0.001). The location of NPOTS was determined in all patients using 4D flow and concerned the main pulmonary artery in 42%.

DATA CONCLUSION

Compared to TTE, 4D flow MRI provides better sensitivity to detect and locate NPOTS in patients with TGA treated by ASO. 4D flow PV measurements in NPOTS were well correlated with TTE PV and RV mass.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1699-1705.

Abnormal Pulmonary Artery Bending Correlates With Increased Right Ventricular Afterload Following the Arterial Switch Operation

PURPOSE

In transposition of great arteries, increased right ventricular (RV) afterload is observed following arterial switch operation (ASO), which is not always related to pulmonary artery (PA) stenosis. We hypothesize that abnormal PA bending from the Lecompte maneuver may affect RV afterload in the absence of stenosis. Thus, we sought to identify novel measurements of three-dimensional cardiac magnetic resonance (CMR) images of the pulmonary arteries and compare with conventional measurements in their ability to predict RV afterload.

METHODS

Conventional measurements and novel measurements of the pulmonary arteries were performed using CMR data from 42 ASO patients and 13 age-matched controls. Novel measurements included bending angle, normalized radius of curvature (R_c), and normalized weighted radius of curvature (R_c-w). Right ventricular systolic pressures (as the surrogate for RV afterload) were measured by either recent echocardiogram or cardiac catheterization.

RESULTS

Conventional measurements of proximal PA size correlated with differential pulmonary blood flow (r = 0.49, P = .001), but not with RV peak systolic pressures (r = -0.26, P = .18). In ASO patients, R_c-w correlated with higher RV systolic pressures (r = -0.57, P = .002). Larger neoaortic areas and rightward bending angles correlated with smaller right pulmonary artery R_c (r = -0.48, P = .001; r = 0.41, P = .01, respectively). Finally, both pulmonary arteries had significantly smaller R_c compared to normal controls.

CONCLUSIONS

Pulmonary arteries exhibit abnormal bends following ASO that correlate with increased RV afterload, independent of PA stenosis. Future work should focus on clinical and hemodynamic contributions of these shape parameters.

Computational Study of Pulmonary Flow Patterns After Repair of Transposition of Great Arteries

Patients that undergo the arterial switch operation (ASO) to repair transposition of great arteries (TGA) can develop abnormal pulmonary trunk morphology with significant long-term complications. In this study, cardiovascular magnetic resonance was combined with computational fluid dynamics to investigate the impact of the postoperative layout on the pulmonary flow patterns. Three ASO patients were analyzed and compared to a volunteer control. Results showed the presence of anomalous shear layer instabilities, vortical and helical structures, and turbulent-like states in all patients, particularly as a consequence of the unnatural curvature of the pulmonary bifurcation. Streamlined, mostly laminar flow was instead found in the healthy subject. These findings shed light on the correlation between the post-ASO anatomy and the presence of altered flow features, and may be useful to improve surgical planning as well as the long-term care of TGA patients.

Invasive Hemodynamics of Adult Congenital Heart Disease: From Shunts to Coarctation

Adults with congenital heart disease are a growing population with increasingly more complex disease, in large part due to improvements in delivery of care to the pediatric population. Cardiac catheterization is an integral component of diagnosis and management in these patients. Careful attention to detail and a thorough understanding of intracardiac hemodynamics are critical to performing complete diagnostic evaluations. This article outlines the most commonly encountered lesions with guidelines for invasive assessment to help guide further therapy.

The year 2017 in the European Heart Journal-Cardiovascular Imaging: Part II

European Heart Journal - Cardiovascular Imaging was launched in 2012 as a multimodality cardiovascular imaging journal. It has gained an impressive impact factor of 8.366 during its first 5 years and is now established as one of the top 10 cardiovascular journals and has become the most important cardiovascular imaging journal in Europe. The most important studies from 2017 will be highlighted in two reports. Part I of the review will focus on studies about myocardial function and risk prediction, myocardial ischaemia, and emerging techniques in cardiovascular imaging, while Part II will focus on valvular heart disease, heart failure, cardiomyopathies, and congenital heart disease.

Large Calibre Self-Expanding Stents for Pulmonary Stenosis After the Arterial Switch, a Low-Risk Solution to a Low-Flow Situation

Branch pulmonary artery stenosis is one of the most common complications late after the arterial switch operation. The pathophysiology of stenosis in these circumstances is very different to that encountered in with normally related great vessels. The LeCompte manoeuvre leaves the pulmonary arteries straddled and stretched over the aortic root which contributing significantly to the degree of stenosis encountered. Unilateral branch pulmonary artery stenosis rarely leads to significant symptoms in young patients with biventricular repairs; however, significant discrepancies in the split flows between right and left lung may place the patient in an unfavourable physiological position as they move in to middle age. Balloon expandable stent implantation distorts the anatomical arrangement of the LeCompte and is associated with negative interactions with the often dilated aortic root. We present three cases of the use of flexible self-expanding stents to improve the physiological flow distributions to each lung whilst hopefully decreasing the risk of erosion and perforation or fistula formation related to the pulmonary artery. All three patients had uncomplicated procedures with significant improvements in vessel diameter and flow distribution noted on follow-up MRI scans. This is the first report of the use of self-expanding stents in the context of branch pulmonary artery stenosis after the LeCompte manoeuvre. Theoretically and based on our early experience, this technique provides potential safety advantages over the use of more traditional balloon expandable stents.