Usefulness of Routine Coronary CT Angiography in Patients with Transposition of the Great Arteries After an Arterial Switch Operation

Enhancing diagnostic performance and image quality in coronary CT angiography: Impact of SnapShot Freeze 2 algorithm across varied heart rates in stent patients

PURPOSE

To investigate the enhancement of image quality achieved through the utilization of SnapShot Freeze 2 (SSF2), a comparison was made against the results obtained from the original SnapShot Freeze algorithm (SSF) and standard motion correction (STND) in stent patients undergoing coronary CT angiography (CCTA) across the entire range of heart rates.

MATERIALS AND METHODS

A total of 118 patients who underwent CCTA, were retrospectively included in this study. Images of these patients were reconstructed using three different algorithms: SSF2, SSF, and STND. Objective assessments include signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diameters of stents and artifact index (AI). The image quality was subjectively evaluated by two readers.

RESULTS

Compared with SSF and STND, SSF2 had similar or even higher quality in the parameters (AI, SNR, CNR, inner diameters) of coronary artery, stent, myocardium, MV (mitral valve), TV (tricuspid valve), AV (aorta valve), and PV (pulmonary valve), and aortic root (AO). Besides the above structures, SSF2 also demonstrated comparable or even higher subjective scores in atrial septum (AS), ventricular septum (VS), and pulmonary artery root (PA). Furthermore, the enhancement in image quality with SSF2 was significantly greater in the high heart rate group compared to the low heart rate group. Moreover, the improvement in both high and low heart rate groups was better in the SSF2 group compared to the SSF and STND group. Besides, when using the three algorithms, an effect of heart rate variability on stent image quality was not detected.

CONCLUSION

Compared to SSF and STND, SSF2 can enhance the image quality of whole-heart structures and mitigate artifacts of coronary stents. Furthermore, SSF2 has demonstrated a significant improvement in the image quality for patients with a heart rate equal to or higher than 85 bpm.

Outcomes of coronary artery obstructions after the arterial switch operation for transposition of the great arteries

OBJECTIVE

Coronary obstruction is a rare but common complication of the arterial switch operation for transposition of the great arteries. The majority of patients remain asymptomatic and no risk factors allow targeting for reinforced surveillance. We aim to review the natural history of patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries and occurrence of coronary-related outcomes.

METHODS

We retrospectively reviewed medical records of the 102 patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries in our institution from 1981 to 2022. Outcomes were anti-ischemic treatment introduction, revascularization (surgical or percutaneous angioplasty), and death; investigations that motivated revascularization were also reviewed.

RESULTS

Twenty-eight out of 102 patients presented with myocardial ischemia during the immediate postoperative phase, 31 were diagnosed when symptomatic, and 43 were identified at the presymptomatic stage, according to our screening policy in preschool-aged children. Stenosis-related event occurrence was, respectively, 29 out of 31 and 32 out of 43 in the latter 2 subgroups. Coronary-related mortality reached 10% in patients diagnosed when symptomatic; no patients died in the presymptomatic subgroup. Of the 28 low-risk patients with no signs of ischemia at diagnosis, 10 developed obstruction warranting reintervention during follow-up. Revascularization was motivated by appearance of symptoms in patients with severe stenosis in normal coronary dispositions, and by clinical symptoms or documented silent ischemia in abnormal coronary patterns.

CONCLUSIONS

Occurrence of stenosis-related events remains significant in patients after arterial switch operation, underlining the importance of early diagnosis for timely intervention. Initial anatomical evaluation identifies stenotic and at-risk patients; this will require periodical function testing. Follow-up modalities can be tailored to a patient's individual anatomic characteristics.

ACR Appropriateness Criteria® Congenital or Acquired Heart Disease

Pediatric heart disease is a large and diverse field with an overall prevalence estimated at 6 to 13 per 1,000 live births. This document discusses appropriateness of advanced imaging for a broad range of variants. Diseases covered include tetralogy of Fallot, transposition of great arteries, congenital or acquired pediatric coronary artery abnormality, single ventricle, aortopathy, anomalous pulmonary venous return, aortopathy and aortic coarctation, with indications for advanced imaging spanning the entire natural history of the disease in children and adults, including initial diagnosis, treatment planning, treatment monitoring, and early detection of complications. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Exercise electrocardiogram for risk-based screening of severe residual coronary lesion in children after coronary surgery

BACKGROUND

Residual severe coronary artery (CA) lesion (SCL) in children after cardiac surgery involving the CA is a major concern.

AIM

To evaluate the value of exercise electrocardiogram (eECG) for risk-based screening of SCL.

METHODS

We analysed 135 maximal eECG from 115 children (mean age 13.6±3.7 years) who underwent concomitant CA imaging. SCL was defined as a stenosis exceeding 50%.

RESULTS

Underlying congenital heart diseases were transposition of the great arteries (TGA) (n = 116), CA pathway anomaly (n = 13) and left CA from the pulmonary artery (n = 6). Eleven SCLs were identified in 10 patients, of which 3 had a known untreated non-severe lesion and 4 had no lesions on previous imaging. In multivariable analysis, risks markers for SCL were effort chest pain (OR: 4.72, 95% CI: 1.23-18.17; P=0.024), intramural pathway (OR: 4.37, 95% CI: 1.14-16.81; P=0.032). Yacoubs C-type CA was added as a risk marker for patients with TGA (P=0.0009). All patients with SCL had a positive eECG (sensitivity: 100%, 95% CI: 72-100). Specificity was 81% (95% CI: 73-87). In the low-risk group (0 risk markers), 3/95 patients had SCL (3%), and the post-test probability of SCL with positive eECG (PPr+) was 15% (95% CI: 8-21). In the high-risk group (≥1 risk marker) comprising 8/40 SCLs (20%), PPr+ was 53% (95% CI: 35-67).

CONCLUSIONS

Most SCL tended to develop gradually, years after surgery. Provided it is near maximal, a negative eECG appears sufficient to exclude SCL. In the high-risk group, PPr+ exceeded 50%.

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.

Acquired anomalies of the coronary arteries after arterial switch operation. Usefulness of coronary computed tomography angiography and impact on follow-up

INTRODUCTION

Mortality and morbidity in patients with transposition of the great arteries after an arterial switch operation depends mainly on the status of coronary perfusion. Coronary computed tomography angiography (CCTA) provides accurate information on coronary morphology, however its use in these patients is not yet routine procedure.

OBJECTIVE

We sought to assess its accuracy to identify acquired coronary anomalies in this population, compared to conventional angiography in a subset of patients, and assess its impact on postoperative management.

METHODS

Retrospective analysis of clinical data on transposition of the great arteries in patients who underwent CCTA between January 2013 and September 2017.

RESULTS

Between January 2013 and September 2017, 18 patients underwent CCTA. Seven patients (39%) disclosed iatrogenic coronary lesions (stenosis 1; kinking 2, occlusion 1; filiform coronary 3). The exam was performed in 78% of patients due to suggestion of myocardial ischemia (symptoms or altered exams). Only 16% needed to undergo additional exams, and in four patients the CCTA result modified therapeutic management. Conventional coronary angiography was also performed in 10 patients (55%), and in three cases, the results were discordant with underestimation or non-identification of coronary lesions on conventional angiography. The medium radiation dose used was 2.4 mSv and no complications after CT were reported.

CONCLUSION

CCTA accurately identified iatrogenic postoperative coronary lesions and it has proven to be superior to conventional angiography in this population. It should be performed routinely in this group of patients, even in the absence of symptoms.

Acquired anomalies of the coronary arteries after arterial switch operation. Usefulness of coronary computed tomography angiography and impact on follow-up

INTRODUCTION

Mortality and morbidity in patients with transposition of the great arteries after an arterial switch operation depends mainly on the status of coronary perfusion. Coronary computed tomography angiography (CCTA) provides accurate information on coronary morphology, however its use in these patients is not yet routine procedure.

OBJECTIVE

We sought to assess its accuracy to identify acquired coronary anomalies in this population, compared to conventional angiography in a subset of patients, and assess its impact on postoperative management.

METHODS

Retrospective analysis of clinical data on transposition of the great arteries in patients who underwent CCTA between January 2013 and September 2017.

RESULTS

Between January 2013 and September 2017, 18 patients underwent CCTA. Seven patients (39%) disclosed iatrogenic coronary lesions (stenosis 1; kinking 2, occlusion 1; filiform coronary 3). The exam was performed in 78% of patients due to suggestion of myocardial ischemia (symptoms or altered exams). Only 16% needed to undergo additional exams, and in four patients the CCTA result modified therapeutic management. Conventional coronary angiography was also performed in 10 patients (55%), and in three cases, the results were discordant with underestimation or non-identification of coronary lesions on conventional angiography. The medium radiation dose used was 2.4 mSv and no complications after CT were reported.

CONCLUSION

CCTA accurately identified iatrogenic postoperative coronary lesions and it has proven to be superior to conventional angiography in this population. It should be performed routinely in this group of patients, even in the absence of symptoms.

Long-Term Survival and Freedom From Coronary Artery Reintervention After Arterial Switch Operation for Transposition of the Great Arteries: A Population-Based Nationwide Study

Background The aim of this study was to evaluate long-term survival and freedom from coronary artery reintervention after the arterial switch operation (ASO). Methods and Results This single-center nationwide retrospective study included consecutive children who underwent ASO between 1990 and 2016 (n=605). Long-term outcomes were obtained by cross-mapping individual data with the National Death Registry and the National Registry of Cardiovascular Interventions for adults. A control group was randomly retrieved at a 1:10 ratio from the National Birth and Death Registries. Early mortality was 3.3% and late mortality was 1.7% during a median follow-up of 10 (interquartile range, 5-16) years. The probability of overall survival at 20 years after ASO was 94.9% compared with 99.5% in the background population (hazard ratio [HR] 15.6; 95% CI, 8.9-27.5, P<0.001). Independent multivariable predictors of worse survival were an intramural coronary artery (HR, 5.2; 95% CI, 1.8-15.2, P=0.002) and period of ASO 1990 to 1999 (HR, 4.6; 95% CI, 1.5-13.6, P<0.001). Fourteen patients (2.3%) required 16 coronary artery reoperations. Freedom from coronary artery reintervention at 20 years after ASO was 96%. The only independent multivariable predictor associated with a higher hazard for coronary artery reintervention was an intramural coronary artery (HR, 33.9; 95% CI, 11.8-97.5, P<0.001). Conclusions Long-term survival after ASO is excellent. Coronary artery reinterventions are rare. An intramural coronary artery was an independent predictor associated with a higher risk for coronary artery reintervention and death, regardless of the surgical period.

Role of Computed Tomography in Pre- and Postoperative Evaluation of a Double-Outlet Right Ventricle

Double-outlet right ventricle (DORV) is a type of ventriculoarterial connection in which both great arteries arise entirely or predominantly from the right ventricle. The morphology of DORV is characterized by a ventricular septal defect (location and relationship with the semilunar valve); bilateral coni and aortomitral continuity; the presence or absence of outflow tract obstruction; tricuspid-pulmonary annular distance; and associated cardiac anomalies. The surgical approach varies with the type of DORV and is based on multiple variables. Computed tomography (CT) is a robust diagnostic tool for the preoperative and postoperative assessment of DORV. Unlike echocardiography and magnetic resonance imaging (MRI), CT imaging is not limited by small acoustic window, need for anaesthesia and can be used in patients with metallic implants. Current generations CT scanners with high spatial and temporal resolution, wide detectors, high-pitch scanning mode, dose-reduction algorithms, and advanced three-dimensional post-processing tools provide a low-risk, high-quality alternative to diagnostic cardiac catheterization or MRI, and have been increasingly utilized in nearly every type of congenital heart defect, including DORV.

Evaluation of Coronary Circulation after Arterial Switch Operation

BACKGROUND

Coronary artery evaluation remains after arterial switch operation a clinical challenge.

OBJECTIVE

This study aims to correlate anatomical changes diagnosed by cardiac computed tomography (CCT) with physiological alterations on clinical evaluation to diagnose coronary obstruction in late ASO patients.

METHODS

This study included 61 consecutive patients with mean age of 9.4 years who underwent ASO. The patients were submitted to echocardiography, electrocardiography, cardiopulmonary exercise test, and cardiac computed tomography to evaluate functional capacity and coronary artery anatomy.

RESULTS

Cardiac computed tomography revealed that only 3.3% of the patients had coronary stenosis. These patients were asymptomatic, and no signs of myocardial ischemia were detected by the tests.

CONCLUSION

The incidence of coronary abnormalities in late ASO patients was 3.3% in our cohort. There is no clear guideline as to why, when, and how these patients should be screened or what to propose when a coronary obstruction is diagnosed in asymptomatic patients.

Imaging Features of Complications after Coronary Interventions and Surgical Procedures

Coronary artery interventions and surgical procedures are used in the treatment of coronary artery disease and some congenital heart diseases. Cardiac and noncardiac complications can occur at variable times after these procedures, with the clinical presentation ranging from asymptomatic to devastating symptoms. Invasive coronary angiography is the reference standard modality used in the evaluation of coronary arteries, with intravascular US and optical coherence tomography providing high-resolution information regarding the vessel wall. CT is the mostly commonly used noninvasive imaging modality in the evaluation of coronary artery intervention complications and allows assessment of the stent, lumen of the stent, lumen of the coronary arteries, and extracoronary structures. MRI is limited to the evaluation of the proximal coronary arteries but allows comprehensive evaluation of the myocardium, including ischemia and infarction. The authors review the clinical symptoms and pathophysiologic and imaging features of various complications of coronary artery interventions and surgical procedures. Complications of percutaneous coronary interventions are discussed, including restenosis, thrombosis, dissection of coronary arteries or the aorta, coronary wall rupture or perforation, stent deployment failure, stent fracture, stent infection, stent migration or embolism, and reperfusion injury. Complications of several surgical procedures are reviewed, including coronary artery bypass grafting, coronary artery reimplantation procedure (for anomalous origin from opposite sinuses or the pulmonary artery or as part of surgical procedures such as arterial switching surgery and the Bentall and Cabrol procedures), coronary artery unroofing, and the Takeuchi procedure. Online supplemental material is available for this article. ^©RSNA, 2021.

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.

Further Improving Image Quality of Cardiovascular Computed Tomography Angiography for Children With High Heart Rates Using Second-Generation Motion Correction Algorithm

BACKGROUND

The state-of-art motion correction algorithm is inadequate for correcting motion artifacts in coronary arteries in cardiovascular computed tomography angiography (CCTA) for children with high heart rates, and even less effective for heart structures beyond coronary arteries.

PURPOSE

This study aimed to evaluate the effectiveness of a second-generation, whole-heart motion correction algorithm in improving the heart image quality of CCTA for children with high heart rates.

MATERIALS AND METHODS

Forty-two consecutive symptomatic cardiac patients with high heart rates (122.6 ± 18.8 beats/min) were enrolled. All patients underwent CCTA on a 256-row CT using a prospective electrocardiogram-triggered single-beat protocol. Images were reconstructed using a standard algorithm (STD), state-of-the-art first-generation coronary artery motion correction algorithm (MC1), and second-generation, whole-heart motion correction algorithm (MC2). The image quality of the origin of left coronary, right coronary, aortic valve, pulmonary valve, mitral valve, tricuspid valve, aorta root, pulmonary artery root, ventricular septum (VS), and atrial septum (AS) was assessed by 2 experienced radiologists using a 4-point scale (1, nondiagnostic; 2, detectable; 3, measurable; and 4, excellent); nonparametric test was used to analyze and compare the differences among 3 groups; and post hoc multiple comparisons were used between different methods.

RESULTS

There were group differences for cardiac structures except VS and AS, with MC2 having the best image quality and STD having the worst image quality. Post hoc multiple comparisons showed that MC2 was better than MC1 and STD in all structures except VS and AS where all 3 algorithms performed equally, whereas MC1 was better than STD only in the origin of left coronary, right coronary, and mitral valve.

CONCLUSIONS

A second-generation, whole-heart motion correction algorithm further significantly improves cardiac image quality beyond the coronaries in CCTA for pediatric patients with high heart rates.

Modified Closed Coronary Transfer is a Good Alternative to the Trap-Door Method During Arterial Switch Operation: a Retrospective Propensity-Matched Comparison

Objective

To compare the early and long-term results of patients in whom was performed modified closed coronary transfer with the results of patients in whom was performed trap-door transfer techniques by utilizing propensity-matching analysis to provide optimal identical patient matching for the groups.

Methods

From August 2015 to December 2017, 127 consecutive patients underwent arterial switch operation due to simple and complex transposition of the great arteries, with or without additional arch and complex coronary pattern, by a single surgical team included into the study. Of these, in 70 patients it was performed modified closed coronary transfer technique and in 57 patients it was performed trap-door style coronary transfer technique. The patients were divided into two groups in terms of coronary transfer method. In the final model, after propensity matching, 47 patients from each group having similar propensity score were included into the study.

Results

There was no significant difference between the groups regarding patient characteristics. Cross-clamp time and operation time were significantly lower in the modified technique group compared with the other group (P=0.03 and P=0.05, respectively). When compared the early and late postoperative outcomes, there was no significant difference between the groups. Postoperative echocardiographic findings were mostly similar between the groups.

Conclusion

The patients in whom was performed our modified technique demonstrate overall good outcomes and the current technique ensures shorter arterial cross-clamp and operation times. It may be an alternative method to the trap-door technique for the coronary transfer during the arterial switch operation.

Neoaortic Regurgitation in Patients with Transposition Long Term After an Arterial Switch Operation and Its Relation to the Root Diameters and Surgical Technique Used

Neoaortic regurgitation and root dilatation are common findings in patients with transposition after an arterial switch operation. The aim of this study was to describe the relation between neoaortic regurgitation long term after an arterial switch procedure, aortic root diameters, and surgical technique used. We also assessed the agreement of the neoaortic regurgitation grade and root diameters in different imaging modalities. For this retrospective study, we qualified 56 consecutive patients who, according to our institutional protocol, had a routine postoperative evaluation of more than 16 years with multimodality imaging studies. Neoaortic regurgitation was assessed by both transthoracic echocardiography and magnetic resonance imaging, and the root diameters obtained by echocardiography and tomography were compared to the reference values and associated with the presence of neoaortic insufficiency. Neoaortic insufficiency was present in 75% of examined patients; the vast majority of them had trace or mild regurgitation, and its qualitative evaluation was significantly different between echocardiography and magnetic resonance imaging. In our study group, the neoaortic valve and aortic sinus were larger in relation to the normal values, and they were significantly correlated with the presence of neoaortic insufficiency, but not with the surgical technique used. Values obtained by echocardiography and tomography correlated well but were significantly different. Transthoracic echocardiography has a tendency to overestimate the severity of regurgitation compared to magnetic resonance imaging. Neoaortic valve and sinus dilatation are significantly correlated with valve insufficiency, but in most cases of root dilatation, the valve remains competent.

Can we predict potentially dangerous coronary patterns in patients with transposition of the great arteries after an arterial switch operation?

INTRODUCTION

Coronary artery complications are the main reason for early mortality after an arterial switch operation. Late complications are relatively rare, and there is no consensus regarding the need or indications for routine follow-up coronary artery evaluations or the best first-line assessment modality. The aim of this study was to present the long-term post-operative frequency of coronary abnormalities in asymptomatic patients with transposition of the great arteries discovered by coronary CT angiography and potential "red flags" revealed by other examinations.

PATIENTS AND METHODS

A group of 50 consecutive asymptomatic patients who underwent routine long-term coronary artery evaluation after an arterial switch operation according to our institutional protocol were qualified for this study. This routine in-hospital visit included a detailed medical interview, electrocardiography, echocardiography, Holter electrocardiography examinations, and laboratory and cardiopulmonary exercise tests. Patients who showed significant abnormalities were qualified for perfusion scintigraphy.

RESULTS

Unfavourable coronary abnormalities were detected in 30 patients (60%) and included ostial stenosis, muscular bridge, coronary fistula, interarterial course, proximal kinking, high ellipticity index, proximal acute angulation (<30 degree) of the left coronary artery, and proximal acute angulation of the right coronary artery. These features could not be predicted based on the medical interviews, surgical reports, or non-invasive screening test results.

CONCLUSION

Complex coronary configurations with potentially dangerous coronary features are common in patients with transposition after an arterial switch operation. Such high-risk patients cannot be identified indirectly, and coronary CT angiography provides accurate information that is useful for post-operative management.

Identifying Subclinical Coronary Abnormalities and Silent Myocardial Ischemia After Arterial Switch Operation

The incidence of late coronary complications is reported around 8% after arterial switch operation (ASO) for d-transposition of the great arteries, but the affected patients are usually asymptomatic. Exercise stress test (EST) and myocardial perfusion imaging (MPI) are common non-invasive modalities to screen for silent myocardial ischemia, but their diagnostic reliability in children after ASO is unclear. We retrospectively reviewed asymptomatic patients following ASO with EST, MPI, and coronary imaging studies (CIS) and examined the reliability of each test in identifying abnormal coronary lesions responsible for myocardial ischemia. Thirty-seven asymptomatic patients (24 males; ages 12.7 ± 3.7 years) had EST, in which 27 and 33 patients also underwent MPI and CIS, respectively. Exercise capacity was comparable to the age- and sex-matched 37 controls. In seven patients with angiographically proven moderate to severe coronary abnormalities, only two patients had positive EST and/or MPI, and five patients were negative including one patient who later developed exercise-induced cardiac arrest due to severe proximal left coronary artery stenosis. Two patients with positive EST or MPI showed no corresponding coronary abnormalities by CIS. Occurrence of acquired late coronary abnormalities did not correlate with the original coronary anatomy or initial surgical procedures. There is no single reliable method to identify the risk of myocardial ischemia after ASO. Although CIS are regarded as a gold standard, multidisciplinary studies are essential to risk-stratify the potential life-threatening coronary lesions after ASO in children.

Interpretation and Reporting of Coronary Arteries in Transposition of the Great Arteries: Cross-sectional Imaging Perspective

Knowledge of coronary artery nomenclature in transposition of the great arteries is essential, given the increasing population of adults with congenital heart disease and greater utilization of imaging in these patients. This article reviews appropriate terminology for describing coronary artery anatomy, commonly encountered coronary artery patterns, and postoperative coronary complications in the setting of transposition of the great arteries.