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.

Progression of an Artificial Intelligence Chatbot (ChatGPT) for Pediatric Cardiology Educational Knowledge Assessment.

Artificial intelligence chatbots, like ChatGPT, have become powerful tools that are disrupting how humans interact with technology. The potential uses within medicine are vast. In medical education, these chatbots have shown improvements, in a short time span, in generalized medical examinations. We evaluated the overall performance and improvement between ChatGPT 3.5 and 4.0 in a test of pediatric cardiology knowledge. ChatGPT 3.5 and ChatGPT 4.0 were used to answer text-based multiple-choice questions derived from a Pediatric Cardiology Board Review textbook. Each chatbot was given an 88 question test, subcategorized into 11 topics. We excluded questions with modalities other than text (sound clips or images). Statistical analysis was done using an unpaired two-tailed t-test. Of the same 88 questions, ChatGPT 4.0 answered 66% of the questions correctly (n = 58/88) which was significantly greater (p < 0.0001) than ChatGPT 3.5, which only answered 38% (33/88). The ChatGPT 4.0 version also did better on each subspeciality topic as compared to ChatGPT 3.5. While acknowledging that ChatGPT does not yet offer subspecialty level knowledge in pediatric cardiology, the performance in pediatric cardiology educational assessments showed a considerable improvement in a short period of time between ChatGPT 3.5 and 4.0.

Incremental value of machine learning for risk prediction in tetralogy of Fallot.

OBJECTIVE: Machine learning (ML) can facilitate prediction of major adverse cardiovascular events (MACEs) in repaired tetralogy of Fallot (rTOF). We sought to determine the incremental value of ML above expert clinical judgement for risk prediction in rTOF. METHODS: Adult congenital heart disease (ACHD) clinicians (≥10 years of experience) participated (one cardiac surgeon and four cardiologists (two paediatric and two adult cardiology trained) with expertise in heart failure (HF), electrophysiology, imaging and intervention). Clinicians identified 10 high-yield variables for 5-year MACE prediction (defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia and HF). Risk for MACE (low, moderate or high) was assigned by clinicians blinded to outcome for adults with rTOF identified from an institutional database (n=25 patient reviews conducted by five independent observers). A validated ML model identified 10 variables for risk prediction in the same population. RESULTS: Prediction by ML was similar to the aggregate score of all experts (area under the curve (AUC) 0.85 (95% CI 0.58 to 0.96) vs 0.92 (0.72 to 0.98), p=0.315). Experts with ≥20 years of experience had superior discriminative capacity compared with <20 years (AUC 0.98 (95% CI 0.86 to 0.99) vs 0.80 (0.56 to 0.93), p=0.027). In those with <20 years of experience, ML provided incremental value such that the combined (clinical+ML) AUC approached ≥20 years (AUC 0.85 (95% CI 0.61 to 0.95), p=0.055). CONCLUSIONS: Robust prediction of 5-year MACE in rTOF was achieved using either ML or a multidisciplinary team of ACHD experts. Risk prediction of some clinicians was enhanced by incorporation of ML suggesting that there may be incremental value for ML in select circumstances.

Factors Associated With Acute Kidney Injury After Cardiopulmonary Bypass in Children.

Background: Acute kidney injury (AKI) is a common complication after cardiovascular surgery in children, noted in approximately 40% of children undergoing cardiopulmonary bypass (CPB). We sought to determine the risk factors including inflammatory and vascular endothelial markers associated with AKI in children undergoing cardiac surgery. Methods: A secondary analysis of a prospective observational cohort study of paediatric patients with a cardiac defect requiring CPB and a weight of >2.5 kg was performed. AKI was defined as a 1.5 times increase from the preoperative value in serum creatinine or an absolute increase by ≥0.3 mg/dL (≥26.5 µmol/L). Plasma inflammatory markers (interleukin [IL]-1a, IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, and tumour necrosis factor α) and vascular endothelial markers (vascular endothelial growth factor, von Willebrand factor, regulated on activation, normal T-cell expressed and secreted, granulocyte macrophage colony-stimulating factor, monocyte chemoattractant protein-1, platelet-derived growth factor, and microparticles) were assessed at 5 perioperative time points. Associations with AKI were found using generalized linear regression models adjusted for repeated measures. Results: A total of 207 patients were assessed, of whom 56% (n = 116) were male. Thirty-three percent (n = 68) developed AKI. In univariable analyses, adverse outcomes significantly related to the presence of AKI included increased intensive care unit stay (3.0 vs 5.6 hours, P < 0.001). In multivariable analysis, independent factors that were significantly associated with AKI included longer duration of CPB (111 vs 154 minutes, P < 0.001) and lower preoperative creatinine. Inflammatory and vascular endothelial biomarkers were not associated with AKI. Conclusions: AKI remains a prevalent problem after cardiac surgery, and renal ischemia related to longer bypass time potentially plays a key role in the etiology. Inflammatory and vascular endothelial biomarkers were not significantly related to AKI.

Contexte: L'insuffisance rénale aiguë (IRA) est une complication fréquente qui survient chez les enfants après une intervention chirurgicale cardiovasculaire. Environ 40 % des enfants chez qui une circulation extracorporelle (CEC) est mise en place durant l'intervention présentent ultérieurement une IRA. Nous avons tenté de définir les facteurs de risque, y compris les marqueurs inflammatoires et endothéliaux vasculaires, qui sont associés à l'IRA chez les enfants qui subissent une intervention chirurgicale cardiaque. Méthodologie: Nous avons réalisé une analyse secondaire d'une étude de cohorte observationnelle prospective menée auprès d'enfants qui étaient atteints d'une anomalie cardiaque nécessitant une CEC et qui pesaient plus de 2,5 kg. L'IRA était définie comme une hausse du taux de créatinine sérique par un facteur de 1,5 par rapport à la valeur préopératoire ou comme une augmentation absolue de ≥ 0,3 mg/dL (≥ 26,5 µmol/l). Les marqueurs inflammatoires plasmatiques (interleukine [IL]-1a, IL-1b, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, facteur de nécrose tumorale alpha) et les marqueurs endothéliaux vasculaires (facteur de croissance de l'endothélium vasculaire, facteur de von Willebrand, chimiokine exprimée et sécrétée après l'activation des lymphocytes T normaux, facteur de stimulation des granulocytes et macrophages, protéine chimiotactique des monocytes-1, facteur de croissance dérivé des plaquettes, microparticules) ont été évalués à 5 moments périopératoires différents. Les associations avec l'IRA ont été établies au moyen de modèles de régression linéaire généraux, qui ont été ajustés pour tenir compte des mesures répétées. Résultats: L'évaluation a porté sur 207 patients, dont 56 % (n = 116) étaient des garçons, et une IRA a été observée chez 33 % (n = 68) d'entre eux. Les résultats d'analyses univariées ont montré que les issues indésirables associées de façon significative à la présence d'une IRA comprenaient un séjour prolongé à l'unité de soins intensifs (3,0 c. 5,6 heures, p < 0,001). Dans les analyses multivariées, les facteurs indépendants associés de façon significative à une IRA comprenaient une CEC prolongée (111 c. 154 minutes, p < 0,001) et un faible taux de créatinine préopératoire. Les biomarqueurs inflammatoires et endothéliaux vasculaires n'ont pas été associés à l'IRA. Conclusions: L'IRA demeure un problème répandu après une intervention chirurgicale cardiaque. L'ischémie rénale associée à une CEC prolongée joue potentiellement un rôle clé dans son étiologie. Par ailleurs, les biomarqueurs inflammatoires et endothéliaux vasculaires n'ont pas été associés de façon significative à l'IRA.

Understanding the literature: Complexity of statistical methods used in high-impact cardiothoracic surgery research.

OBJECTIVE: Biostatistics are frequently used in research published in the domain of cardiothoracic surgery. The objective of this study was to describe the scope of statistical techniques reported in the literature and to highlight implications for editorial review and critical appraisal. METHODS: Original research articles published between January and April 2017 in the Journal of Thoracic and Cardiovascular Surgery, Annals of Thoracic Surgery, and the European Journal of Cardio-Thoracic Surgery were examined. For each article, the statistical method(s) reported were recorded and categorized by complexity. RESULTS: We reviewed 293 articles that reported 1068 statistical methods. The mean number of different statistical methods reported per article was 3.6 ± 1.9, with variation by subspecialty and journal. The most common statistical methods were contingency tables (in 59% of articles), t tests (49%), and survival methods (49%). Only 4% of articles used descriptive statistics alone. An introductory level of statistical knowledge was deemed sufficient for understanding 16% of articles, whereas for the remainder a higher level of knowledge would be needed. CONCLUSIONS: Contemporary cardiothoracic surgery research frequently requires the use of complex statistical methods. This was evident across articles for all cardiothoracic surgical subspecialties as reported in 3 high-impact journals. Routine review of manuscript submissions by biostatisticians is needed to ensure the appropriate use and reporting of advanced statistical methods in cardiothoracic surgery research.

"Splint" Mitral Valve Repair for Destructive Endocarditis in Children.

Medical management of infective endocarditis in the pediatric population has an associated in-hospital mortality rate of up to 25%. In the past, infective endocarditis of the mitral valve was surgically managed with a valve replacement. Now, there is a shift toward repair. However, for complex lesions in pediatric patients, many institutions are still hesitant to perform a mitral valve repair. We describe the cases of three children with destructive mitral valve endocarditis and risk factors for higher perioperative mortality and morbidity who were successfully treated with a complex mitral valve repair with "splint" patch plasty of the posteromedial commissure.

Surgery for Tumors of the Heart.

Most surgeons will encounter only a handful of primary cardiac tumors outside of myxomas. Approximately 3 quarters of primary cardiac tumors are benign and 1 quarter is malignant. In most cases, cardiac tumors are silent but when symptoms do occur, they are primarily determined by tumor size and anatomical location, not by histopathology. The diagnosis and preoperative imaging relies heavily on multimodal imaging including echocardiography, computed tomography, magnetic resonance imaging, and coronary angiography. Surgical resection is the most common treatment for most simple primary cardiac tumors and for some complex benign tumors. Surgical resection of primary cardiac tumors frequently involves the need for complex cardiac reconstruction, particularly when malignant. Secondary tumors to the heart are 30 times more frequent than primary cardiac tumors, and their incidence is increasing, largely as a result of advances in cancer diagnosis and therapy. Surgical resection is feasible in only a small fraction of highly-selected patients with secondary tumors to the heart. For complex benign tumors-such as paraganglioma or large fibromas-and all primary and secondary malignant tumors, a multidisciplinary cardiac tumor team review in experienced centers of excellence is recommended.

Annulus-Sparing Tetralogy of Fallot Repair: Low Risk and Benefits to Right Ventricular Geometry.

BACKGROUND: Annulus-sparing repair of tetralogy of Fallot (TOF) carries a potential increased risk of reoperation for restenosis and unproven benefits on right ventricular (RV) geometry. METHODS: Primary TOF repairs (n = 434) between 2000 and 2012 were studied using risk-adjusted parametric techniques. Progression of cardiac dimensions was analyzed using repeated measures regression using reports of all 2,103 echocardiograms undertaken throughout the study period, to a maximum follow-up of 13.7 years. RESULTS: Repair was at a mean age of 180 days: AS approach in 296 (68%) patients; and transannular patch in 138 (32%). Intraoperative revisions (for residual stenosis) were required in 135 patients (29%). There have been 4 deaths (survival 99%). Surgical reoperation for recurrent right ventricular outflow tract stenosis was occasionally required in both groups at comparable rates (transannular patch, 5 of 136 [4%]; annulus-sparing repair, 14 of 296 [5%]; p = 0.83). Larger increases in RV end-diastolic dimensions were evident in transannular patch patients versus annulus-sparing repair patients (p < 0.0001). Other risks for RV dilation included worse grade of postoperative pulmonary regurgitation, larger right ventricular end-diastolic dimension at the time of diagnosis, and higher operative weight (all p < 0.0001). Factors associated with successful annulus-sparing repair included (1) pulmonary annulus greater than 7 mm, right ventricular end-diastolic dimension greater than 1.2 cm, and tricuspid annulus greater than 1.4 cm (all preoperatively); and (2) right ventricular outflow tract diameter greater than 10 mm and right ventricular systolic pressure less than 50 mm Hg (both intraoperatively after repair). CONCLUSIONS: Pursuit of annulus-sparing repair strategies can lower the use of transannular patch to approximately 30% with low risk of reoperation for the patient. Annulus-sparing repair is associated with significantly reduced long-term RV dilation. Pulmonary valve enlargement to approximately 10 mm and right ventricular systolic pressure less than 50 mm Hg during annulus-sparing repair are associated with low risk of recurrent stenosis.

Young infants with severe tetralogy of Fallot: Early primary surgery versus transcatheter palliation.

BACKGROUND: Infants with severe tetralogy of Fallot may undergo (1) early primary surgical repair (EARLY) or (2) early transcatheter palliation (CATH) before delayed surgical repair. We compared these strategies with (3) elective single-stage tetralogy of Fallot repair (IDEAL). METHODS: From 2000 to 2012, 453 children underwent tetralogy of Fallot repair (excluding systemic-pulmonary shunts), including 383 in the IDEAL (75%), 42 in the EARLY (9%), and 28 in the CATH (6%) groups. IDEAL repair at The Hospital for Sick Children occurs after 3 months. Risk-adjusted hazard analysis compared freedom from surgical or catheter reintervention. Somatic size, branch pulmonary artery size, and right ventricle systolic pressure were modeled using 2780 echocardiogram reports via mixed-model regression. RESULTS: CATH involved right ventricular outflow tract stent in 18 patients, right ventricular outflow tract balloon in 9 patients, and ductal-stent in 1 patient. Three patients died (1 per group). Risk-adjusted freedom from surgical reoperation was 89% ± 4%, 88% ± 5%, and 85% ± 6% for the IDEAL, EARLY, and CATH groups, respectively, at 10 years. Patients in the EARLY and CATH groups had similar reoperation rates, except for neonates (<1 month), for whom EARLY repair conferred an increased risk of reoperation. Risk-adjusted freedom from catheter reintervention was lower in the EARLY group (76%) and especially for the CATH group (53%) at 10 years versus the IDEAL group (83%). Somatic growth and progression of right ventricle systolic pressure were similar among groups at 8 years. Although those undergoing EARLY (P = .02) and CATH (P = .09) tend to have smaller branch pulmonary arteries initially, late pulmonary artery size was not significantly different among groups. CONCLUSIONS: Early primary repair for neonates may increase surgical reoperation, whereas transcatheter palliation comes at a cost of increased catheter reintervention. However, overall outcomes between groups, in terms of survival, growth, and hemodynamic parameters, were comparable, suggesting that both strategies are a reasonable option for children with severe tetralogy of Fallot.

NASA Model of "Threat and Error" in Pediatric Cardiac Surgery: Patterns of Error Chains.

BACKGROUND: We introduced the National Aeronautics and Space Association threat-and-error model to our surgical unit. All admissions are considered flights, which should pass through stepwise deescalations in risk during surgical recovery. We hypothesized that errors significantly influence risk deescalation and contribute to poor outcomes. METHODS: Patient flights (524) were tracked in real time for threats, errors, and unintended states by full-time performance personnel. Expected risk deescalation was wean from mechanical support, sternal closure, extubation, intensive care unit (ICU) discharge, and discharge home. Data were accrued from clinical charts, bedside data, reporting mechanisms, and staff interviews. Infographics of flights were openly discussed weekly for consensus. RESULTS: In 12% (64 of 524) of flights, the child failed to deescalate sequentially through expected risk levels; unintended increments instead occurred. Failed deescalations were highly associated with errors (426; 257 flights; p < 0.0001). Consequential errors (263; 173 flights) were associated with a 29% rate of failed deescalation versus 4% in flights with no consequential error (p < 0.0001). The most dangerous errors were apical errors typically (84%) occurring in the operating room, which caused chains of propagating unintended states (n = 110): these had a 43% (47 of 110) rate of failed deescalation (versus 4%; p < 0.0001). Chains of unintended state were often (46%) amplified by additional (up to 7) errors in the ICU that would worsen clinical deviation. Overall, failed deescalations in risk were extremely closely linked to brain injury (n = 13; p < 0.0001) or death (n = 7; p < 0.0001). CONCLUSIONS: Deaths and brain injury after pediatric cardiac surgery almost always occur from propagating error chains that originate in the operating room and are often amplified by additional ICU errors.

Aggressive Patch Augmentation May Reduce Growth Potential of Hypoplastic Branch Pulmonary Arteries After Tetralogy of Fallot Repair.

BACKGROUND: Potential surgical strategies for hypoplastic branch pulmonary arteries (BPAs) during tetralogy of Fallot repair include (1) extensive patch augmentation to the hilum (PATCH), (2) limited extension arterioplasty to the proximal pulmonary artery (EXTENSION), or (3) leaving the native vessels unaugmented (NATIVE). We explored the effect of these strategies on reintervention and BPA growth. METHODS: From 2000 to 2012, 434 children underwent complete tetralogy of Fallot repair. Risk-adjusted parametric models were used to analyze the risk of BPA reintervention for (1) all children, (2) children with BPAs of 4 mm or smaller, and (3) children with BPAs of 3 mm or smaller. Repeated-measures analysis of more than 2,000 echocardiograms was used to characterize postoperative BPA growth and right ventricular pressure by using nonlinear mixed models. RESULTS: Overall survival (99% [3 deaths]) was excellent. The 10-year freedom from BPA reintervention was 84%. In risk-adjusted models (including baseline BPA z-score), PATCH had a decreased freedom from reintervention (73%; p < 0.01) vs EXTENSION (87%) or NATIVE (91%). For children with BPAs of 4 mm or smaller (28 PATCH, 60 EXTENSION, 75 NATIVE), baseline characteristics were similar. The risk-adjusted 5-year freedom from reintervention was 68% for PATCH, 76% for EXTENSION, and 85% for NATIVE. PATCH trended toward an increased risk of reintervention (p = 0.07). For children with BPAs of 4 mm or smaller left in their NATIVE state, only ∼15% required reintervention. After adjustment for baseline BPA z-score, the time-related BPA growth was decreased (p < 0.014) and right ventricular pressure was increased (p = 0.03) for the PATCH group. CONCLUSIONS: Aggressive PATCH augmentation of hypoplastic BPAs improves the short-term geometry but may lead to late stenosis and higher rates of reintervention. Hypoplastic BPAs in tetralogy of Fallot tend (∼85%) to grow well without instrumentation.

Aortic valve repair for insufficiency in older children offers unpredictable durability that may not be advantageous over a primary Ross operation†.

OBJECTIVES: To evaluate the durability of aortic valve (AoV) repair relative to other strategies for children with significant aortic insufficiency (AI). METHODS: From 2001 to 2012, 90 children with greater than or equal to moderate AI underwent surgery. Resulting procedures were classified according to final operative outcome: AoV repair (repair; n = 46, 51%), Ross procedure (Ross; n = 21, 23%) or replacement with mechanical or tissue prosthesis [aortic valve replacement (AVR); n = 23, 26%]. Repeated measures (n = 1081 echocardiograms) mixed-model analysis and parametric multiphase risk-adjusted hazard analysis were used to evaluate haemodynamic parameters and durability of operations. RESULTS: Mean age at operation was similar for repair and Ross groups, but slightly higher for the AVR group (10.6, 11 and 13.2, respectively; P = 0.04). Baseline annular dimensions were similar among groups. Of 46 repairs, 85% involved pericardial leaflet extensions (commonly with leaflet shaving and/or commisuroplasty). The remaining repairs were commissuroplasties. On multivariable analysis, repair was associated with increased early (∼1-2 years) AI and increased outflow tract peak pressure gradients relative to Ross and AVR procedures. On univariate analysis, repairs tended to have a larger annulus size compared with Ross or AVR; however, this was not significant on multivariable analysis. There were 25 reinterventions (surgical reoperation = 16; transcatheter intervention = 9) for 22 children. Freedom from surgical reoperation was 64, 100 and 51% at 6 years for repairs, Ross and AVR, respectively (P = 0.05); however, three of five reoperations after AVR were for failed bioprosthetic devices. The freedom from reintervention was not significantly influenced by the type of AoV operation (P = 0.43). CONCLUSIONS: Durability of aortic valve repair for children is limited by recurrence of AI and/or stenosis, often within the first few years. After repair, reoperation should be anticipated within ∼7 years.

National Aeronautics and Space Administration "threat and error" model applied to pediatric cardiac surgery: error cycles precede ∼85% of patient deaths.

BACKGROUND: We hypothesized that the National Aeronautics and Space Administration "threat and error" model (which is derived from analyzing >30,000 commercial flights, and explains >90% of crashes) is directly applicable to pediatric cardiac surgery. METHODS: We implemented a unit-wide performance initiative, whereby every surgical admission constitutes a "flight" and is tracked in real time, with the aim of identifying errors. The first 500 consecutive patients (524 flights) were analyzed, with an emphasis on the relationship between error cycles and permanent harmful outcomes. RESULTS: Among 524 patient flights (risk adjustment for congenital heart surgery category: 1-6; median: 2) 68 (13%) involved residual hemodynamic lesions, 13 (2.5%) permanent end-organ injuries, and 7 deaths (1.3%). Preoperatively, 763 threats were identified in 379 (72%) flights. Only 51% of patient flights (267) were error free. In the remaining 257 flights, 430 errors occurred, most commonly related to proficiency (280; 65%) or judgment (69, 16%). In most flights with errors (173 of 257; 67%), an unintended clinical state resulted, ie, the error was consequential. In 60% of consequential errors (n = 110; 21% of total), subsequent cycles of additional error/unintended states occurred. Cycles, particularly those containing multiple errors, were very significantly associated with permanent harmful end-states, including residual hemodynamic lesions (P < .0001), end-organ injury (P < .0001), and death (P < .0001). Deaths were almost always preceded by cycles (6 of 7; P < .0001). CONCLUSIONS: Human error, if not mitigated, often leads to cycles of error and unintended patient states, which are dangerous and precede the majority of harmful outcomes. Efforts to manage threats and error cycles (through crew resource management techniques) are likely to yield large increases in patient safety.