Computational Characterization of Mechanical, Hemodynamic, and Surface Interaction Conditions: Role of Protein Adsorption on the Regenerative Response of TEVGs.

Currently available small diameter vascular grafts (<6 mm) present several long-term limitations, which has prevented their full clinical implementation. Computational modeling and simulation emerge as tools to study and optimize the rational design of small diameter tissue engineered vascular grafts (TEVG). This study aims to model the correlation between mechanical-hemodynamic-biochemical variables on protein adsorption over TEVG and their regenerative potential. To understand mechanical-hemodynamic variables, two-way Fluid-Structure Interaction (FSI) computational models of novel TEVGs were developed in ANSYS Fluent 2019R3® and ANSYS Transient Structural® software. Experimental pulsatile pressure was included as an UDF into the models. TEVG mechanical properties were obtained from tensile strength tests, under the ISO7198:2016, for novel TEVGs. Subsequently, a kinetic model, linked to previously obtained velocity profiles, of the protein-surface interaction between albumin and fibrinogen, and the intima layer of the TEVGs, was implemented in COMSOL Multiphysics 5.3®. TEVG wall properties appear critical to understand flow and protein adsorption under hemodynamic stimuli. In addition, the kinetic model under flow conditions revealed that size and concentration are the main parameters to trigger protein adsorption on TEVGs. The computational models provide a robust platform to study multiparametrically the performance of TEVGs in terms of protein adsorption and their regenerative potential.

Staged repair of transposition of the great arteries with anomalous coronary anatomy and complete atrioventricular canal.

The association of complete atrioventricular canal with transposition of the great arteries is rare, with a prevalence of less than 3-5%. We present an 18-month-old patient with a complete atrioventricular canal, side-by-side transposition of the great arteries, and anomalous coronary anatomy, managed initially with pulmonary banding and then by arterial switch with complete atrioventricular canal repair at early infancy.

International quality improvement initiatives.

Across the globe, the implementation of quality improvement science and collaborative learning has positively affected the care and outcomes for children born with CHD. These efforts have advanced the collective expertise and performance of inter-professional healthcare teams. In this review, we highlight selected quality improvement initiatives and strategies impacting the field of cardiovascular care and describe implications for future practice and research. The continued leveraging of technology, commitment to data transparency, focus on team-based practice, and recognition of cultural norms and preferences ensure the success of sustainable models of global collaboration.

Differences by Altitude in the Frequency of Congenital Heart Defects in Colombia.

More evidence is needed that links the diagnosis of different congenital heart diseases (CHD) identified after birth, with intermediate altitudes above sea level in geographically and ethnically diverse populations. Our aim was to estimate relative frequencies of CHD diagnosis by altitude and gender in the pediatric population of 12 cities in Colombia. This was a cross-sectional study based on the information collected between 2008 and 2013 in Colombia, during annual congenital heart disease (CHD) case detection campaigns in the post-natal period. All children underwent physical examination, pulse-oximetry, and echocardiography. The odds ratio (OR) was used as the summary statistic to assess associations with altitude in the relative frequency of CHD diagnosis. Data from 5900 children who attended the campaigns were evaluated (54.3 % male), out of which 3309 (56.1 %) were diagnosed with CHD. There were statistically significant differences in the relative distribution of the different CHD by city altitude and gender (p < 0.0001). When compared with sea level, altitudes between 1285 and 3000 m above sea level were associated with increased Patent Ductus Arteriosus (PDA) (ORmh 1.68, 95 % CI 1.34-2.09; p < 0.0001) and left ventricular outflow tract obstruction (LVOTO) diagnoses (ORmh 2.06, 95 % CI 1.63-2.61; p < 0.0001), while the opposite was true for right ventricular outflow tract (RVOTO) diagnosis (OR 0.60; 95 % CI 0.49-0.74, p < 0.0001). These associations were not modified by gender differences. In a geographically and ethnically diverse population, altitudes between 1285 and 3000 m above sea level carried an independent and clinically important excess diagnostic risk of PDA and of LVOTO, when compared to all other CHD.

Preoperative Malnutrition Increases Risk of In-Hospital Mortality, Major Infection, and Longer Intensive Care Unit Stay After Ventricular Septal Defect Closure.

BACKGROUND: High energy requirements and poor feeding can lead to growth failure in patients with ventricular septal defect (VSD), but effects of preoperative malnutrition on surgical outcomes are poorly understood, especially in low-resource settings. METHODS AND RESULTS: We analyzed a cohort of children <5 years of age undergoing VSD closure at 60 global centers participating in the International Quality Improvement Collaborative for Congenital Heart Disease, 2015 to 2020. We calculated adjusted odds ratios (ORs) for in-hospital death and major infection and adjusted coefficients for duration of intensive care unit stay for 4 measures of malnutrition: severe wasting (weight-for-height Z score, <-3), moderate wasting (-3

Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography for Diagnosis and Treatment of Chylopericardium After Cardiac Transplantation.

Chylopericardium is a rare complication after cardiac transplantation. We report a case of a 69-year-old woman with persistent chylopericardium after a heart transplantation due to Chagas disease. Failure of conservative treatment led to dynamic contrast-enhanced magnetic resonance lymphangiography and percutaneous radiologic intervention of the lymphatic leakage and symptoms resolution.

COVID-19 international experience in paediatric patients with congenital heart disease.

OBJECTIVE: As COVID-19 continues to affect the global population, it is crucial to study the impact of the disease in vulnerable populations. This study of a diverse, international cohort aims to provide timely, experiential data on the course of disease in paediatric patients with congenital heart disease (CHD). METHODS: Data were collected by capitalising on two pre-existing CHD registries, the International Quality Improvement Collaborative for Congenital Heart Disease: Improving Care in Low- and Middle-Income Countries and the Congenital Cardiac Catheterization Project on Outcomes. 35 participating sites reported data for all patients under 18 years of age with diagnosed CHD and known COVID-19 illness during 2020 identified at their institution. Patients were classified as low, moderate or high risk for moderate or severe COVID-19 illness based on patient anatomy, physiology and genetic syndrome using current published guidelines. Association of risk factors with hospitalisation and intensive care unit (ICU) level care were assessed. RESULTS: The study included 339 COVID-19 cases in paediatric patients with CHD from 35 sites worldwide. Of these cases, 84 patients (25%) required hospitalisation, and 40 (12%) required ICU care. Age <1 year, recent cardiac intervention, anatomical complexity, clinical cardiac status and overall risk were all significantly associated with need for hospitalisation and ICU admission. A multivariable model for ICU admission including clinical cardiac status and recent cardiac intervention produced a c-statistic of 0.86. CONCLUSIONS: These observational data suggest risk factors for hospitalisation related to COVID-19 in paediatric CHD include age, lower functional cardiac status and recent cardiac interventions. There is a need for further data to identify factors relevant to the care of patients with CHD who contract COVID-19 illness.

Recommendations for developing effective and safe paediatric and congenital heart disease services in low-income and middle-income countries: a public health framework.

The global burden of paediatric and congenital heart disease (PCHD) is substantial. We propose a novel public health framework with recommendations for developing effective and safe PCHD services in low-income and middle-income countries (LMICs). This framework was created by the Global Initiative for Children's Surgery Cardiac Surgery working group in collaboration with a group of international rexperts in providing paediatric and congenital cardiac care to patients with CHD and rheumatic heart disease (RHD) in LMICs. Effective and safe PCHD care is inaccessible to many, and there is no consensus on the best approaches to provide meaningful access in resource-limited settings, where it is often needed the most. Considering the high inequity in access to care for CHD and RHD, we aimed to create an actionable framework for health practitioners, policy makers and patients that supports treatment and prevention. It was formulated based on rigorous evaluation of available guidelines and standards of care and builds on a consensus process about the competencies needed at each step of the care continuum. We recommend a tier-based framework for PCHD care integrated within existing health systems. Each level of care is expected to meet minimum benchmarks and ensure high-quality and family centred care. We propose that cardiac surgery capabilities should only be developed at the more advanced levels on hospitals that have an established foundation of cardiology and cardiac surgery services, including screening, diagnostics, inpatient and outpatient care, postoperative care and cardiac catheterisation. This approach requires a quality control system and close collaboration between the different levels of care to facilitate the journey and care of every child with heart disease. This effort was designed to guide readers and leaders in taking action, strengthening capacity, evaluating impact, advancing policy and engaging in partnerships to guide facilities providing PCHD care in LMICs.

Intraoperative Diagnosis of ALCAPA Complicating an Aortopulmonary Window Repair.

We present the case of transient left ventricular dysfunction secondary to impaired left coronary artery filling after aortopulmonary window repair, caused by intraoperative diagnosis of anomalous left coronary artery from pulmonary artery. Immediate recognition and repair allowed for uneventful recovery of the patient.

Atrial approaches in mitral valve surgery: a propensity analysis of differences in the incidence of clinically relevant adverse effects.

BACKGROUND: The lack of evidence on complications using mitral valve approaches leaves the choice of risk exposure to the surgeon's preference, based on individual experience, speed, ease, and quality of exposure. METHODS: The present study analysed patients undergoing mitral valve surgery using a superior transseptal approach or a left-atrial approach between 2006 and 2018. We included first-time elective mitral valve procedures, isolated, or combined, without a history of rhythm disturbances. We used propensity score matching based on 26 perioperative variables. The primary endpoint was the association between the superior transeptal approach and clinically significant adverse outcomes, including arrhythmias, need for a permanent pacemaker, cerebrovascular events, and mortality. RESULTS: A total of 652 patients met the inclusion criteria; 391 received the left atrial approach, and 261 received the superior transseptal approach. After matching, 96 patients were compared with 69 patients, respectively. The distribution of the preoperative and perioperative variables was similar. There was no difference in the incidence of supraventricular tachyarrhythmias or the need for treatment. The incidence of nodal rhythm (p = 0.008) and length of stay in intensive care (p = 0.04) were higher in the superior transseptal group, but the need for permanent pacemaker implantation was the same. Likewise, there was no difference in the need for anticoagulation due to arrhythmia, the incidence of cerebrovascular events or mortality in the postoperative period or in the long-term follow-up. CONCLUSION: We did not find an association with permanent heart rhythm disorders or any other significant adverse clinical outcome. Therefore, the superior transeptal approach is useful and safe for mitral valve exposure.

Blood-Vessel-Inspired Hierarchical Trilayer Scaffolds: PCL/Gelatin-Driven Protein Adsorption and Cellular Interaction.

Fabrication of scaffolds with hierarchical structures exhibiting the blood vessel topological and biochemical features of the native extracellular matrix that maintain long-term patency remains a major challenge. Within this context, scaffold assembly using biodegradable synthetic polymers (BSPs) via electrospinning had led to soft-tissue-resembling microstructures that allow cell infiltration. However, BSPs fail to exhibit the sufficient surface reactivity, limiting protein adsorption and/or cell adhesion and jeopardizing the overall graft performance. Here, we present a methodology for the fabrication of three-layered polycaprolactone (PCL)-based tubular structures with biochemical cues to improve protein adsorption and cell adhesion. For this purpose, PCL was backbone-oxidized (O-PCL) and cast over a photolithography-manufactured microgrooved mold to obtain a bioactive surface as demonstrated using a protein adsorption assay (BSA), Fourier transform infrared spectroscopy (FTIR) and calorimetric analyses. Then, two layers of PCL:gelatin (75:25 and 95:5 w/w), obtained using a novel single-desolvation method, were electrospun over the casted O-PCL to mimic a vascular wall with a physicochemical gradient to guide cell adhesion. Furthermore, tensile properties were shown to withstand the physiological mechanical stresses and strains. In vitro characterization, using L929 mouse fibroblasts, demonstrated that the multilayered scaffold is a suitable platform for cell infiltration and proliferation from the innermost to the outermost layer as is needed for vascular wall regeneration. Our work holds promise as a strategy for the low-cost manufacture of next-generation polymer-based hierarchical scaffolds with high bioactivity and resemblance of ECM's microstructure to accurately guide cell attachment and proliferation.

2640 Meters Closer to the Stars: Does High Altitude Affect Fontan Results?

BACKGROUND: Risk factors for and postoperative results of the Fontan operation in patients living at high altitude (>2500 meters above sea level) in the Andean region remain unknown. This study was conducted to evaluate immediate postoperative outcomes and to assess short- and long-term functional class after the Fontan operation. METHODS: From June 2003 to February 2019, 104 patients receiving the Fontan procedure at 2640 meters (8661 feet) above sea level were retrospectively studied. Preoperative catheterization, intraoperative variables, and postoperative outcomes were described. Functional class was evaluated in patients living permanently below (group I) and at or higher than 2500 meters (8202 feet) above sea level (group II). Risk factors for mortality were analyzed. RESULTS: Median age at operation was 8.5 ± 4.4 years; pulmonary artery pressure, 16.2 ± 3.6 mm Hg; end-diastolic systemic ventricular pressure, 13.3 ± 3.8 mm Hg; and pulmonary vascular resistance index, 2.1 (interquartile range, 07-3.7) Wood units. Chest tube duration was 8.5 (6-12) days. Mortality was 4.8%, with 0 in the last 5 years. Higher preoperative pulmonary pressure (16.2 ± 3.6 mm Hg vs 21.2 ± 3.40 mm Hg; P = .01), aortic cross-clamp time (P < .001), and renal failure (P < .01) were associated with mortality. Functional class improved to class I in 86.4%. Overall survival was 90.7% at 10 years of follow-up. CONCLUSIONS: Increased pulmonary pressure and pulmonary vascular resistance index are directly related to high altitude. The Fontan-Kreutzer operation performed at high altitude in the Andean region is feasible with good results. We routinely fenestrate all cases to avoid dysfunction in the early postoperative period. Functional status is adequate after the operation.

Access to paediatric cardiac surgery in Colombia: a population-based study.

OBJECTIVES: Globally congenital heart disease mortality is declining, yet the proportion of infant deaths attributable to heart disease rises in Colombia and other middle-sociodemographic countries. We aimed to assess the accessibility of paediatric cardiac surgery (PCS) to children <18 years of age in 2016 in the South American country of Colombia. METHODS: In Bogotá, Colombia, a multi-national team used cross-sectional and retrospective cohort study designs to adapt and evaluate 4 health system indicators at the national level: first, the population with timely geographic access to an institution providing PCS; second, the number of paediatric cardiac surgeons; third, this specialized procedure volume and its national distribution; and fourth, the 30-day perioperative mortality rate after PCS in Colombia. RESULTS: Geospatial mapping approximates 64% (n = 9 894 356) of the under-18 Colombian population lives within 2-h drivetime of an institution providing PCS. Twenty-eight cardiovascular surgeons report performing PCS, 82% (n = 23) with formal training. In 2016, 1281 PCS procedures were registered, 90% of whom were performed in 6 of the country's 32 departments. National non-risk-adjusted all-cause 30-day perioperative mortality rate after PCS was 2.73% (n = 35). CONCLUSIONS: Colombia's paediatric population had variable access to cardiac surgery in 2016, largely dependent upon geography. While the country may have the capacity to provide timely, high-quality care to those who need it, our study enables future comparative analyses to measure the impact of health system interventions facilitating healthcare equity for the underserved populations across Colombia and the Latin American region.

Failure Analysis of TEVG's II: Late Failure and Entering the Regeneration Pathway.

Tissue-engineered vascular grafts (TEVGs) are a promising alternative to treat vascular disease under complex hemodynamic conditions. However, despite efforts from the tissue engineering and regenerative medicine fields, the interactions between the material and the biological and hemodynamic environment are still to be understood, and optimization of the rational design of vascular grafts is an open challenge. This is of special importance as TEVGs not only have to overcome the surgical requirements upon implantation, they also need to withhold the inflammatory response and sustain remodeling of the tissue. This work aims to analyze and evaluate the bio-molecular interactions and hemodynamic phenomena between blood components, cells and materials that have been reported to be related to the failure of the TEVGs during the regeneration process once the initial stages of preimplantation have been resolved, in order to tailor and refine the needed criteria for the optimal design of TEVGs.

Failure Analysis of TEVG's I: Overcoming the Initial Stages of Blood Material Interaction and Stabilization of the Immune Response.

Vascular grafts (VG) are medical devices intended to replace the function of a diseased vessel. Current approaches use non-biodegradable materials that struggle to maintain patency under complex hemodynamic conditions. Even with the current advances in tissue engineering and regenerative medicine with the tissue engineered vascular grafts (TEVGs), the cellular response is not yet close to mimicking the biological function of native vessels, and the understanding of the interactions between cells from the blood and the vascular wall with the material in operative conditions is much needed. These interactions change over time after the implantation of the graft. Here we aim to analyze the current knowledge in bio-molecular interactions between blood components, cells and materials that lead either to an early failure or to the stabilization of the vascular graft before the wall regeneration begins.

Current Status of Training and Certification for Congenital Heart Surgery Around the World: Proceedings of the Meetings of the Global Council on Education for Congenital Heart Surgery of the World Society for Pediatric and Congenital Heart Surgery.

The optimal training of the highly specialized congenital heart surgeon is a long and complex process, which is a significant challenge in most parts of the world. The World Society for Pediatric and Congenital Heart Surgery (WSPCHS) has established the Global Council on Education for Congenital Heart Surgery as a nonprofit organization with the goal of assessing current training and certification and ultimately establishing standardized criteria for the training, evaluation, and certification of congenital heart surgeons around the world. The Global Council and the WSPCHS have reviewed the present status of training and certification for congenital cardiac surgery around the world. There is currently lack of consensus and standardized criteria for training in congenital heart surgery, with significant disparity between continents and countries. This represents significant obstacles to international job mobility of competent congenital heart surgeons and to the efforts to improve the quality of care for patients with Congenital Heart Disease worldwide. The purpose of this article is to summarize and document the present state of training and certification in congenital heart surgery around the world.

Surgical management of a giant right coronary artery aneurysm with coronary arteriovenous fistula: case report.

BACKGROUND: Coronary artery aneurysms (CAAs) are uncommon, and giant aneurysms (>2 cm) are even more unusual. Coronary atherosclerosis and Kawasaki disease are the leading causes for this pathology. The treatment for this condition is controversial because the evidence is based on case report series. CASE SUMMARY: We describe the case of a 77-year-old female patient who presented with heart failure symptoms. She was diagnosed with a giant saccular aneurysm arising from the right coronary artery (RCA) ostium and a fistula between the RC and the left anterior descending artery (LAD) to the coronary sinus. And an atrial septal defect (ASD) and severe tricuspid regurgitation were also found. The patient underwent surgery through a medium sternotomy, the aneurysm was opened and resected under cardiopulmonary bypass. The RCA was ligated at the distal end of the aneurysm, and a saphenous vein graft bypass was performed. A coronary arteriovenous fistula from the distal portion of RC and LAD artery to a severely enlarged coronary sinus was found and corrected with an autologous pericardial patch. Closure of the ASD was performed with a pericardial patch and a tricuspid ring annuloplasty was done. Post-operative course was uneventful. DISCUSSION: There are few cases of giant coronary aneurysms associated with fistulas reported in the literature. Despite the endovascular percutaneous techniques available to treat these patients, we believe that surgical treatment was the best option for this particular case. We consider that surgical treatment is a very good option for giant CAAs associated with AV fistulas that are not susceptible for current endovascular available devices. The literature lacks evidence regarding the best approach for these cases, and we think that invasive treatment should be tailored according to the heart's anatomy and patient risk.

Early Impact of the COVID-19 Pandemic on Congenital Heart Surgery Programs Across the World: Assessment by a Global Multi-Societal Consortium.

The coronavirus disease 2019 (COVID-19) pandemic currently gripping the globe is impacting the entire health care system with rapidly escalating morbidities and mortality. Although the infectious risk to the pediatric population appears low, the effects on children with congenital heart disease (CHD) remain poorly understood. The closure of congenital heart surgery programs worldwide to address the growing number of infected individuals could have an unintended impact on future health for COVID-19-negative patients with CHD. Pediatric and congenital heart surgeons, given their small numbers and close relationships, are uniquely positioned to collectively assess the impact of the pandemic on surgical practice and care of children with CHD. We present the results of an international survey sent to pediatric and congenital heart surgeons characterizing the early impact of COVID-19 on the care of patients with CHD.

Successful Management of Massive Air Embolism During Cardiopulmonary Bypass Using Multimodal Neuroprotection Strategies.

Complications and critical events during cardiopulmonary bypass (CPB) are very challenging, difficult to manage, and in some instances have the potential to lead to fatal outcomes. Massive cerebral air embolism is undoubtedly a feared complication during CPB. If not diagnosed and managed early, its effects are devastating and even fatal. It is a catastrophic complication and its early diagnosis and intraoperative management are still controversial. This is why the decision-making process during a massive cerebral air embolism represents a challenge for the entire surgical, anesthetic, and perfusion team. All caregivers involved in this event must synchronize their responses quickly, harmoniously, and in such a way that all interventions lead to minimizing the impact of this complication. Its occurrence leaves important lessons to the surgical team that faces it. The best management strategy for a complication of this type is prevention. Nevertheless, a surgical team may ultimately be confronted with such an occurrence at some point despite all the prevention strategies, as was the case with our patient. That is why, in each institution, no effort should be spared to establish cost-effective strategies for early detection and a clear and concise management protocol to guide actions once this complication is detected. It is the duty of each surgical team to determine and clearly organize which strategies will be followed. The purpose of this case study was to demonstrate that a massive air embolism can be rapidly detected using near-infrared spectroscopy monitoring and can be successfully corrected with a multimodal neuroprotection strategy.

Evaluation of Microscopic Structure-Function Relationships of PEGylated Small Intestinal Submucosa Vascular Grafts for Arteriovenous Connection.

Vascular grafts are used as vascular access for hemodialysis, the most common renal replacement therapy to artificially clean blood waste after kidney malfunction. Despite that they are widely used in clinical practice, upon implantation, synthetic vasculars show complications such as thrombogenesis, reduced patency rates, low blood pressure, or even complete collapse. In this study, a C-shaped vascular graft was manufactured with small intestinal submucosa (SIS) and modified on the surface and the bulk of the material via conjugation of polyethylene glycol (PEG) to obtain a biocompatible and less thrombogenic vascular graft than the commercially available polytetrafluoroethylene (ePTFE) vascular grafts. Molecular weight and concentration of PEG molecules were systematically varied to gain insights into the underlying structure-function relationships. We analyzed the chemical, thermal, and mechanical properties of vascular grafts modified with 6 equiv of SIS-PEG 400 as well as cytotoxicity and in vitro platelet deposition. Immune response, patency rates, and extent of regeneration were also tested in vivo with the aid of swine animal models. Results showed that the conjugation levels achieved were sufficient to improve graft compliance, therefore approaching that of native vessels, while platelet deposition was altered leading to a 95% reduction compared with pristine SIS and 92% with respect to ePTFE. H&E staining on explanted samples corroborated SIS-PEG 400 biocompatibility and the ability to promote regeneration. The obtained results set solid foundations for the rational design and manufacture of a regenerative, small diameter vascular graft model and introduce an alternative to ePTFE vascular grafts for hemodialysis access.