Arterial Switch Operation Patients Research Articles

Transcatheter pulmonary valve replacement after arterial switch operation.

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

Increased aortic pressures and pulsatile afterload components promote concentric left ventricular remodeling in adults with transposition of the great arteries and arterial switch operation

BackgroundFunctional abnormalities of the ascending aorta (AA) have been mainly reported in young patients who underwent arterial switch operation (ASO) for transposition of the great arteries (TGA). ObjectivesTo compare systolic, diastolic brachial and central blood pressures (bSBP, bDBP, cSBP, cDBP), aortic biomechanical parameters, and left ventricular (LV) afterload criteria in adult ASO patients with healthy controls and to assess their relationships with LV remodeling and aortic size. Materials and methodsForty-one prospectively enrolled patients (16.8 to 35.8 years) and 41 age- and sex-matched healthy volunteers underwent cardiac MRI to assess LV remodeling with simultaneous brachial BP estimation. After MRI, carotid-femoral tonometry was performed to measure pulse wave velocity (cfPWV), cSBP and cDBP for further calculation of pulse pressure (cPP), AA distensibility (AAD), and AA and LV elastance (AAE, LVE). ResultsbSBP, bDBP, cSBP,cDBP and cPP were all significantly higher in ASO group than in controls: cSBP (116.5 ± 13.8 vs 106.1 ± 12.0, p < 0.001), cDBP (72.5 ± 6.9 vs 67.1 ± 9.4, p = 0.002), cPP (44.0 ± 12.1 vs 39.1 ± 8.9, p = 0.003) and not related to aortic size. AAD were decreased in ASO patients vs controls (4.70 ± 2.72 vs 6.69 ± 2.16, p < 0.001).LV mass was correlated with bSBP, cSBP, cPP (ρ = 0.48; p < 0.001), while concentric LV remodeling was correlated with AAE (ρ = 0.60, p < 0.001) and LVE (ρ = 0.32, p = 0.04), but not with distensibility. ConclusionEven without reaching arterial hypertension, aortic sBP and PP are increased in the adult TGA population after ASO, altering the pulsatile components of afterload and contributing to LV concentric remodeling.

Echocardiographic Midterm and Long-term Outcomes After Arterial Switch Operation for d-Transposition of the Great Arteries: A Single-Institution Experience

INTRODUCTION: Arterial switch operation is the preferred surgical management for d-transposition of the great arteries, but it still has long-term complications, which necessitate continued follow-up of patients. This procedure was first performed in this institution in 1991, and after three decades, there is a need to evaluate midterm and long-term outcomes in this population. METHODS: This is a descriptive study on arterial switch operation patients between January 2010 and March 2019 in this institution. The following parameters were collected through review of charts and online health records (Medtrack): preoperative clinical data, surgical technique and immediate postoperative course and complications, echocardiographic results, and current clinical status. The study was approved by the institutional ethics review board of the hospital. RESULTS: Among the 108 patients included in the study, 35 were long-term patients, and 73 were midterm. A total of 27 patients (25%) were lost to follow-up. Among the remaining patients (n = 81), 76 (94%) were alive. The most common postoperative complications were pulmonary stenosis (n = 11), aortic regurgitation (n = 24), and aortic dilatation (n = 2). One patient had reintervention after surgery for severe pulmonic stenosis. Overall survival function was 93.7% after 5 years (95% confidence interval, 0.81–0.98) and 79.4% after 9 years (95% confidence interval, 0.46–0.93). CONCLUSION: Complications seen in this population are similar to those seen in literature. The overall survival rate after 5 years compares to those of other institutions. However, long-term survival rates were lower, which may be due to poor patient follow-up and a high rate of patient attrition over time. To improve future outcomes, strategies should be implemented to promote continuity of care, and parents should be advised regarding the importance of follow-up. KEYWORDS: arterial switch operation, d-TGA, echocardiography, midterm complications, long term complications, survival rate

Young adults after arterial switch operation for transposition of the great arteries in Switzerland: a growing population.

Adults with transposition of the great arteries (d-TGA) after the arterial switch operation (ASO) are an evolving cohort in adult cardiology. We aimed to analyze cardiac function and cardiac events after transition to the adult clinic in Switzerland. Adults with prior ASO enrolled in the Swiss Adult Congenital HEart disease Registry (SACHER) were included. We analyzed initial cardiac anatomy, surgical history, residual lesions and cardiac function at the time of inclusion, as well as cardiac events during follow-up. Patients were classified as complex (with ventricular septal defect) or simple (with intact interventricular septum) d-TGA. The cohort included 149 patients (99 simple d-TGA, 50 complex d-TGA; age 21±3 years; 71% male, follow-up 27 [15-46] months). Prior to inclusion, patients with complex d-TGA had undergone more interventions related to the left ventricular outflow tract (16% vs. 3%, p = 0.01). Functional and cardiovascular status were similar between the groups. Eleven patients (7%) had a total of 19 cardiac events (5 complications and 14 re-interventions) during follow-up. Patients with complex d-TGA had more cardiac-related complications compared to those with simple d-TGA (8% vs. 1%, p = 0.03). The frequency of re-interventions was not statistically different between the two groups (12% vs. 4%, p = 0.07). During follow-up, an increase in QRS duration was observed. Other parameters of cardiac function remained unchanged. The majority of adult ASO patients have normal functional class and cardiac function. Complex anatomy and residual lesions play a key role when regarding the occurrence of cardiac-related complications during follow-up. The role of QRS prolongation over time needs to be investigated further.

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 ± 8.7years, 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 30g/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.

The coronary arteries in adults after arterial switch: a systematic review

Abstract Background Coronary artery status in adults longterm after the arterial switch operation (ASO) is unclear. As a consequence, current follow-up strategies for coronary assessment remain controversial. We conducted a systemic review to provide an overview of coronary complications during adulthood and to evaluate the value of coronary imaging in adults after ASO, in light of current guidelines. Material and method Studies describing coronary complications or coronary imaging after ASO in adults were considered eligible for review and analysis. Articles were screened for the inclusion of adult ASO patients and data on coronary complications and findings of coronary imaging were collected. In cohort studies with both adults (≥18 years) and non-adults (&amp;lt;18 years) only outcomes in identifiable adults were analyzed. Results A total of 993 adults were followed with a median follow-up of 2.0 years after reaching adulthood. Myocardial ischemia was suspected in 16/192 patients (6.8%). The number of coronary interventions was 4 (0.4%) and coronary death was reported in 4 (0.4%) patients. The following coronary abnormalities were found by routine coronary computer tomography CT (cCT): stenosis (4%), acute angle (40%), kinking (24%) and interaterial course (11%). No coronary events were reported during pregnancy (n=45). Conclusion The reported number of coronary interventions (0.4%) and of coronary death (0.4%) during a median follow-up of 2 years in 993 ASO adults is low. Coronary abnormalities including acute angle, kinking and interarterial course were commonly found by cCT. The 2020 European Society of Cardiology (ESC) guidelines state that routine screening for coronary pathologies is questionable. However, based on current findings and in line with the 2018 American ACC/AHA guidelines we suggest a baseline assessment of the coronary arteries in all adult ASO patients. Thereafter, an individualized coronary follow-up strategy, based upon coronary findings, is advisable. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Hartstichting Freedom from coronary complications

The Coronary Arteries in Adults after the Arterial Switch Operation: A Systematic Review.

Coronary artery status in adults long after the arterial switch operation (ASO) is unclear. We conducted a systematic review to provide an overview of coronary complications during adulthood and to evaluate the value of routine coronary imaging in adults after ASO, in light of current guidelines. Articles were screened for the inclusion of adult ASO patients and data on coronary complications and findings of coronary imaging were collected. A total of 993 adults were followed with a median available follow-up of only 2.0 years after reaching adulthood. Myocardial ischemia was suspected in 17/192 patients (8.9%). The number of coronary interventions was four (0.4%), and coronary death was reported in four (0.4%) patients. A lack of ischemia-related symptoms cannot be excluded because innervation studies indicated deficient cardiac innervation after ASO, although data is limited. Anatomical high-risk features found by routine coronary computed tomography (cCT) included stenosis (4%), acute angle (40%), kinking (24%) and inter-arterial course (11%). No coronary complications were reported during pregnancy (n = 45), although, remarkably, four (9%) patients developed heart failure. The 2020 European Society of Cardiology (ESC) guidelines state that routine screening for coronary pathologies is questionable. Based on current findings and in line with the 2018 American ACC/AHA guidelines a baseline assessment of the coronary arteries in all ASO adults seems justifiable. Thereafter, an individualized coronary follow-up strategy is advisable at least until significant duration of follow-up is available.

The role of exercise testing in congenital heart disease patients after coronary artery reimplantation

IntroductionThe Ross procedure requires like the arterial switch operation (ASO) coronary artery reimplantation. There is no information on coronary artery stenosis at the site of the reimplantation in Ross patients as has been described for ASO patients. This study assessed therefore the prevalence of positive exercise tests (pETs) suggesting myocardial ischemia in Ross and ASO patients in comparison to tetralogy of Fallot patients (TOF), the latter not undergoing coronary artery reimplantation. The study evaluated further, whether a coronary artery complication was confirmed by a supplementary non- and/or invasive evaluation. MethodsResults of exercise tests, echocardiography, coronary computed tomography (CCT) and coronary angiography (CA) were retrospectively reviewed in 30 Ross, 14 ASO and 30 TOF patients. ResultsExercise capacity did not differ between groups. There was a trend to more frequent pETs in Ross patients (Ross vs. ASO vs. TOF, N, %): 8 (27) vs. 1 (7) vs. 2 (7) p = 0.062. CCT was performed in 30% Ross, 21% ASO, 3% TOF (p = 0.023); CA in 20% Ross, 21% ASO and 13% TOF patients (p = 0.727). None of these investigations revealed a coronary artery stenosis. Patients with pET showed a higher right ventricular outflow tract (RVOT) gradient (44 ± 30 vs. 22 ± 13 mmHg, p = 0.004) and more frequently a severe RVOT stenosis (27 vs. 0%, p < 0.006). ConclusionspETs are rather related to RVOT stenosis than to coronary artery complications after Ross procedure, ASO and TOF repair. The role of exercise testing for detection of myocardial ischemia is limited and should be restricted to evaluation of exercise capacity.

Long-term outcomes amongst adults with anatomic repair for transposition of the great arteries: Not as perfect as we would have hoped?

Most of the patients who underwent arterial switch operation (ASO) for D-transposition of the great arteries (D-TGA) reach adulthood. However, they may have residual lesions necessitating lifelong surveillance. We aimed to evaluate the long-term outcomes of a large number of contemporary ASO patients. We examined late major adverse cardiovascular events (MACE) in adult TGA patients (> 16 years) who underwent an ASO between 1980 and 2002 and continued their follow-up in 2 major tertiary ACHD centers. MACE were defined as death, re-intervention, myocardial ischemia, arrhythmia, stroke/transient ischemic attack, infective endocarditis and heart failure. Overall, 306 patients (67% male, mean age 25 ± 5years) were followed in adult life for a median of 8 years [IQR 6–13]. Seventy-three (23.8%) patients experience MACE, including 40 medical events and 60 reinterventions. MACE -free survival at 2, 5, and 10 years of follow-up in adulthood was 93.0%, 85.1%, 70.7%, respectively. Atrial arrhythmia was the most frequent cardiac event with an incidence of 3.8‰ patient-years, whereas the incidence of life-threatening ventricular tachyarrhythmia was 1.7‰. Coronary artery disease was diagnosed in 11 (3.5%) patients. The most frequent indication for cardiac intervention was right ventricular outflow tract obstruction ( n = 40/60, 66.7%) followed by coronary revascularisation procedure ( n = 11/60, 18.3%), Fig. 1 . On multivariate analysis, history of cardiac complications during infancy (HR 2.7, 95%CI:1.6–4.5, P < 0.01) and uncommon coronary patterns (HR for type B/C/D/E versus type A 1.7, 95%CI:1.0–2.9, P = 0.03) were independent predictors of MACE in adulthood. MACE are common in adult patients with ASO for TGA, particularly those with a history of cardiovascular complications during childhood and uncommon coronary pattern. Consequently, all patients with an anatomic repair for TGA merit life-long tertiary care.

Factors Affecting Surgical Mortality for Patients With D-Transposition of the Great Arteries: Single-Institution Experience From a Developing Country

INTRODUCTION: Arterial switch operation (ASO) is the preferred surgical management for D-transposition of the great arteries. It was first performed in this institution in 1991, with a high mortality from the expected learning curve. Two decades later, there is a need to revisit our outcomes to further improve surgical treatment of this common cyanotic condition. METHODS: This is a retrospective cohort study on ASO patients between January 2010 and June 2017 from a single institution. The following parameters were collected through review of patient charts and two-dimensional echocardiography videos: clinical data, laboratory and echocardiographic results, and intraoperative and postoperative outcomes. The study was approved by the institutional ethics review board of the hospital. RESULTS: Among 117 subjects, the median age was 1 month (range, 1 day to 6 years), and 76% were males. Transposition of the great arteries with intact septum (62%) was more frequently seen. Mortality decreased from 49% to 30%. Preoperatively, balloon atrial septostomy was associated with mortality (p = 0.013). Intraoperatively, mortality increased with prolonged cardiopulmonary bypass (p = 0.007), bleeding (p = 0.015), rebypass (p = 0.001), and metabolic acidosis (p = 0.005). Postoperatively, use of inotropes (p = 0.003), prolonged intubation (p = 0.028), pulmonary edema or severe congestion (p = 0.01), bleeding (p &lt; 0.001), increased international normalized ratio (p = 0.047), acute renal failure (p &lt; 0.001), peritoneal dialysis (p &lt; 0.001), metabolic acidosis (p = 0.005), and increased C-reactive protein (p = 0.028) increased mortality. On multivariate analysis, rebypass (95% confidence interval, 1.86–175.49) and renal failure (95% confidence interval, 2.98–109.50) were strong independent predictors of mortality. CONCLUSION: Overall mortality remains high compared with other institutions. Strategies should therefore be used to avoid statistically significant endpoints in order to improve operative outcomes. Careful preoperative planning and early institution of dialysis should be performed when needed. KEYWORDS: D-TGA, arterial switch operation, predictors of mortality, balloon atrial septostomy

Abstract 16754: Novel Characterization of Pulmonary Artery Bending, Rather Than Stenosis, Detects Increased Right Ventricular Afterload and is Associated With Increased Right Ventricular Mass in the Post-Arterial Switch Operation Heart

Introduction: Surgical treatment of transposition of great arteries involves the Arterial Switch Operation (ASO) and the LeCompte maneuver, where the pulmonary artery (PA) and its bifurcation are translocated anterior to the neoaortic root, creating relative PA stenosis and exaggerated PA bending. Assessment of branch PA dimensions can identify stenosis, however complex 3-dimensional bending without clear stenosis may contribute to elevated right ventricular (RV) afterload. Initial data suggest elevated RV afterload and RV mass are prevalent in these patients but the etiology and associated risk factors remain unclear. Hypothesis: In post-ASO patients, more extreme PA bending, as described by radius of curvature, will be associated with elevated RV afterload and RV mass independently of relative PA stenosis. Methods: Retrospective single-center analysis of 22 post-ASO patients was performed, representing native anatomy of D-TGA with (15, 68%) and without (7, 32%) intact ventricular septum, excluding those with PA stent, pulmonary hypertension, or other anatomical confounders. RV systolic pressure (RVSP) was recorded from echocardiography (11, 50%) or catheterization (11, 50%) and correlated to cardiac magnetic resonance (CMR) imaging measurements including: radius of curvature (Rcw) weighted to differential pulmonary blood flow and RV mass indexed to body surface area. Results: In ASO patients, receiver operating characteristic curve demonstrated Rcw, but not PA stenosis, moderately detected presence of elevated RVSP (&gt;40 mmHg) (respectively: AUC 0.84, p = 0.03 and AUC 0.49, p =0.60). Patients with elevated RV Mass had more extreme Rcw (when normalized to body surface area), but no difference in PA stenosis via Nakata index (respectively: p = 0.10, p = 0.02). Conclusions: Abnormal PA bending as described by Rcw is associated with increased RV afterload and RV Mass. Rcw may serve as a promising future clinical proxy to RV afterload.

Echocardiography and MRI parameters associated with exercise capacity in patients after the arterial switch operation

BackgroundThe arterial switch operation (ASO) for transposition of the great arteries has excellent survival, but a substantial number of patients suffer from a reduced exercise capacity. The goal of this study was to identify imaging parameters associated with a reduced exercise capacity in patients after ASO. MethodsA retrospective analysis was performed of ASO patients who underwent cardiopulmonary exercise testing (CPET) between 2007 and 2017. Reduced exercise performance was defined as a reduced workload peak (Wpeak) with Z-score <−2 or a peak oxygen uptake indexed for weight (VO2peak/kg) with Z-score <−2. Data on echocardiography and cardiac magnetic resonance performed within 1 year of the CPET were collected for comparison. ResultsA total of 81 ASO patients (age 17±7 years) were included. Reduced exercise performance was found in 22 patients (27%) as expressed by either a reduced Wpeak and/or a reduced VO2peak/kg. Main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced Wpeak (p=0.031; p=0.020, respectively). The main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced VO2peak/kg (p=0.009; p=0.019, respectively). No left ventricular parameters were found to be associated with abnormal exercise performance. ConclusionThis study demonstrates that ASO patients frequently experience reduced exercise capacity. Echocardiographic evidence of main pulmonary artery stenosis and increased right ventricular pressure were associated with reduced exercise capacity, and are therefore key to monitor during serial follow-up of ASO patients.

P3654Location of the coronary origins in transposition patients following anatomical repair: Implications for invasive coronary angiography and intervention

Abstract Background Surgical repair of transposition of the great arteries (TGA) is most commonly via the arterial switch operation (ASO). This involves translocation of the aorta and pulmonary trunk, typically with anastomosis of the branch pulmonary arteries anteriorly (LeCompte manoeuvre) and re-implantation of the coronary arteries onto the posterior neo-aorta. As such, the position of the coronary ostia may differ from their expected locations. Purpose To use ECG-gated CT angiography to describe the anatomic position of coronary ostia in post-switch TGA patients guiding potential catheter interventions in this population. Methods All post ASO patients who underwent CT imaging between 2008–2018 were identified. Patients with complex anatomy such as double outlet right ventricle were excluded. The positions of the coronary ostia were measured in degrees from vertical on a double-oblique reconstruction in the aortic valve plane. Ostium positions were compared to those of patients with no congenital heart disease via Watson's two-sample test of homogeneity for circular data. Angular dispersion was compared between groups via the Wallraff test. P&lt;0.05 indicated statistical significance. Results Of 206 adult patients with TGA and ASO followed in our adult congenital heart disease centre, 38 (18.4%) had CT imaging available for analysis during the study period (mean age 24±6.8, 75% male). The control group consisted of 15 patients investigated for chest pain (mean age 54±15.1, 73% male). In the control group, the right and left coronary ostia arose at a mean angle of −19 and +125 degrees from vertical (figure 1a). This was significantly different to the mean ASO coronary ostia clustered at mean angles of −70 and +29 degrees from vertical (Watson p&lt;0.001) (figure 1b, with stenosis at the left coronary anastomosis). There was no significant difference in spread of left ostia (Rho 0.9 vs 0.99, p=0.12), but right ostia were significantly more variable in ASO patients than controls (0.71 vs 0.96, p=0.003). Figure 1 Conclusions Coronary ostial positions in the neo-aorta of post-ASO patients differ significantly from those of normal controls, with considerable variability, especially in right coronary position. CT can demonstrate coronary ostia in 3D space and derive appropriate tube angles to guide catheterisation in post-operative congenital cardiac patients, optimise catheter selection, reduce catheterisation tome, radiation and contrast dose.

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

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. 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 (Rc), and normalized weighted radius of curvature (Rc-w). Right ventricular systolic pressures (as the surrogate for RV afterload) were measured by either recent echocardiogram or cardiac catheterization. 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, Rc-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 Rc (r = -0.48, P = .001; r = 0.41, P = .01, respectively). Finally, both pulmonary arteries had significantly smaller Rc compared to normal controls. 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.

Validation of aortic valve 4D flow analysis and myocardial deformation by cardiovascular magnetic resonance in patients after the arterial switch operation

BackgroundAortic regurgitation (AR) and subclinical left ventricular (LV) dysfunction expressed by myocardial deformation imaging are common in patients with transposition of the great arteries after the arterial switch operation (ASO). Echocardiographic evaluation is often hampered by reduced acoustic window settings. Cardiovascular magnetic resonance (CMR) imaging provides a robust alternative as it allows for comprehensive assessment of degree of AR and LV function. The purpose of this study is to validate CMR based 4-dimensional flow quantification (4D flow) for degree of AR and feature tracking strain measurements for LV deformation assessment in ASO patients.MethodsA total of 81 ASO patients (median 20.6 years, IQR 13.5–28.4) underwent CMR for 4D and 2D flow analysis. CMR global longitudinal strain (GLS) feature tracking was compared to echocardiographic (echo) speckle tracking. Agreements between and within tests were expressed as intra-class correlation coefficients (ICC).ResultsEleven ASO patients (13.6%) showed AR > 5% by 4D flow, with good correlation to 2D flow assessment (ICC = 0.85). 4D flow stroke volume of the aortic valve demonstrated good agreement to 2D stroke volume over the mitral valve (internal validation, ICC = 0.85) and multi-slice planimetric LV stroke volume (external validation, ICC = 0.95). 2D flow stroke volume showed slightly less, though still good agreement with 4D flow (ICC = 0.78) and planimetric LV stroke volume (ICC = 0.87). GLS by CMR was normal (− 18.8 ± 4.4%) and demonstrated good agreement with GLS and segmental analysis by echocardiographic speckle tracking (GLS = − 17.3 ± 3.1%, ICC of 0.80).ConclusionsAortic 4D flow and CMR feature tracking GLS analysis demonstrate good to excellent agreement with 2D flow assessment and echocardiographic speckle tracking, respectively, and can therefore reliably be used for an integrated and comprehensive CMR analysis of aortic valve competence and LV deformation analysis in ASO patients.

Long-Term Survival After Arterial Versus Atrial Switch in d-Transposition of the Great Arteries

The arterial switch operation (ASO) became the procedure of choice for dextro-transposition of the great arteries (d-TGA) nearly 30 years ago, but the long-term results of this operation are unknown. We aimed to compare the long-term transplant-free survival of patients with d-TGA who underwent ASO versus atrial switch in the Pediatric Cardiac Care Consortium. We performed a retrospective cohort study of d-TGA patients undergoing ASO or atrial switch in the United States between 1982 and 1991. Long-term transplant-free survival was obtained by linking Pediatric Cardiac Care Consortium data with the National Death Index and the Organ Procurement and Transplant Network. Kaplan-Meier survival plots were constructed, and multivariable regression was used to compare long-term transplant-free survival. Of 554 d-TGA patients who underwent ASO (n= 259) or atrial switch (n= 295), the 20-year overall transplant-free survival was 82.1% for those undergoing ASO and 76.3% for those who had atrial switch procedure. Adjusted overall transplant-free survival beyond 10 years after operation was superior for ASO compared with atrial switch (hazard ratio 0.07, 95% confidence interval: 0.01 to 0.52, p= 0.009). During this period, the ASO had higher in-hospital mortality than the atrial switch (21.6% versus 12.9%, p= 0.007). After excluding patients with in-hospital mortality, the transplant-free survival 20 years after repair was 97.7% for the ASO patients versus 86.3% for the atrial switch patients. Despite initial higher in-hospital mortality for ASO during the study period, there is a significant long-term transplant-free survival advantage for ASO as compared with atrial switch for d-TGA surgery. Ongoing monitoring is required to assess late risk of cardiovascular disease.

Left ventricular remodelling in long-term survivors after the arterial switch operation for transposition of the great arteries.

The objective of this study was to quantify imaging markers of myocardial fibrosis and assess myocardial function in long-term transposition of the great arteries survivors after the arterial switch operation (ASO). Paediatric ASO patients were prospectively studied by cardiac magnetic resonance imaging, including first-pass myocardial perfusion, late gadolinium enhancement, and T1 relaxometry, as well as echocardiography for left ventricular (LV) systolic and diastolic function including strain analysis, with comparison to healthy controls. Thirty ASO patients (mean age 15.4 ± 2.9 years vs. 14.1 ± 2.6 years in 28 controls, P = 0.04) were included. Patients had normal LV ejection fraction (EF) (57 ± 5% vs. 59 ± 5%, P = 0.07), but end-diastolic and end-systolic volumes were increased (104 ± 20 mL/m2 vs. 89 ± 10 mL/m2, P < 0.01 and 46 ± 13 mL/m2 vs. 36 ± 7 mL/m2, P < 0.01, respectively). Longitudinal strain at two-, three-, and four-chamber levels of the LV were lower in ASO patients (-19.0 ± 2.6% vs. -20.9 ± 2.3%, P = 0.006, -17.7 ± 2.0% vs. -19.1 ± 2.4%, P = 0.02, and -18.9 ± 1.9% vs. -20.1 ± 1.7%, P = 0.01, respectively), while circumferential strain was higher at all short-axis levels (-24.6 ± 2.3% vs. -19.3 ± 1.6%, P < 0.001 at the mid-ventricular level). LV native T1 times were higher in ASO patients (1042 ± 27 ms vs. 1011 ± 27 ms, P < 0.01) and correlated with LV mass/volume ratio (R = 0.60, P < 0.001). Myocardial scarring or myocardial perfusion defects were not observed in our cohort. Children and adolescents after ASO have normal LV systolic function, in line with their overall good clinical health. At a myocardial level however, imaging markers of diffuse myocardial fibrosis are elevated, along with an altered LV contraction pattern. Whether these abnormalities will progress into future clinically significant dysfunction and whether they are harbingers of adverse outcomes remains to be studied.

Myocardial Stress Perfusion MRI: Experience in Pediatric and Young-Adult Patients Following Arterial Switch Operation Utilizing Regadenoson.

Dextro-transposition of the great arteries (D-TGA) is one of the most common cyanotic heart lesions. The arterial switch operation (ASO) is the preferred surgical palliation for D-TGA. One of the primary concerns following the ASO is complications arising from the coronary artery transfer. There is a need for myocardial perfusion assessment within ASO patients. There is no report on the utility of regadenoson as a stress agent in children following ASO. Our objective was to observe the safety and feasibility of regadenoson as a pharmacologic stressor for perfusion cardiac MR in a pilot cohort of pediatric and young-adult patients who have undergone ASO. We reviewed our initial experience with regadenoson stress cardiac MR in 36 pediatric and young-adult patients 15.1 ± 4.5years (range 0.2-22years) with history of ASO. The weight was 61.6 ± 21.5kg (range 3.8-93kg). All patients underwent cardiac MR because of concern for ischemia. Subjects' heart rate and blood pressure were monitored and pharmacologic stress was induced by injection of regadenoson. We evaluated their hemodynamic response and adverse effects using changes in vital signs and onset of symptoms. A pediatric cardiologist and radiologist qualitatively assessed myocardial perfusion and viability images. All stress cardiac MR examinations were completed without adverse events. Resting heart rate was 72 ± 13 beats per minute (bpm) and rose to peak of 120 ± 17bpm (95 ± 50% increase, p < 0.005) with regadenoson. Image quality was considered good or diagnostic in all cases. A total of 11/36 (31%) patients had a perfusion defect on the stress FPP images. 14 of the 36 patients (39%) underwent cardiac catheterization within 6months of the CMR and the findings showed excellent agreement. Regadenoson may be a useful coronary hyperemia agent to utilize for pediatric patients following arterial switch procedure when there is concern for ischemia. The ability to administer as a single bolus with one IV makes it advantageous in pediatrics. In a limited number of cases, regadenoson stress perfusion showed excellent agreement with cardiac catheterization.

Long-term quality of life in adult survivors after the arterial switch operation.

We sought to determine the quality of life after the arterial switch operation (ASO) using the Short Form 36 questionnaire in adult survivors. All patients (n = 107) who underwent the ASO and were 18 years of age or older living in the Australian state of Victoria with a contact telephone number were identified from the hospital database. Fifty-one (48%) patients were 18-24 years old and 56 (52%) patients were 25-34 years old. Patients completed the Short Form 36 quality of life questionnaire via telephone. The results of the 8 domains of the Short Form 36 questionnaire and the derived health state summary score (Short Form 6-Dimension) were compared against mean scores from age-matched Australian population data. Compared with the Australian population age-matched data, 18- to 24-year-old ASO patients ranked their health higher in 3 of the 8 domains (P < 0.01). The 25-34 age group ranked their health higher in 4 of the 8 domains (P < 0.01). No statistically significant differences in the mean Short Form 6-Dimension scores were observed in the 18-24 age group (0.769 for ASO patients vs 0.772 for Australian population, P = 0.85) or the 25-34 age group (0.795 for ASO patients vs 0.780 for Australian population, P = 0.33). Young adult survivors of the ASO have similar outcomes to age-matched controls in quality of life measured by Short Form 6-Dimension.