The Society of Thoracic Surgeons Preoperative Beta Blocker Working Group Interim Report.

BACKGROUND: Atrial fibrillation (AF) occurs commonly following cardiac surgery and is associated with multiple adverse outcomes. Older randomized trials suggested that perioperative beta blockade reduced postoperative AF, and the Society of Thoracic Surgeons (STS) CABG composite measure includes beta blocker administration preoperatively within 24 hours of surgery and at discharge. However, some more recent studies suggest preoperative beta blockade has limited value and question its continuation as an STS quality measure. METHODS: In 2022, an STS Preoperative Beta Blocker Working Group was formed with representatives from the STS and the Society of Cardiovascular Anesthesiologists. Published randomized trials, observational studies, societal guidelines, and the current state of available data from the STS Adult Cardiac Surgery Database (ACSD) were reviewed. RESULTS: Review of existing studies reveals substantial heterogeneity or insufficient detail regarding specific beta blockers used; timing of initiation; management of patients on chronic beta blockade; and whether other pro- or anti-arrhythmic drugs were used concurrently. Further, beta blocker data currently collected in the STS ACSD lack sufficient granularity. CONCLUSIONS: As a new randomized trial seems unlikely, the working group believes that more granular data on real-world practice would facilitate assessment of the value of preoperative beta blockade in the current era, development of best practice recommendations, and evaluation of their continued appropriateness as an STS quality metric. STS ACSD participants have been invited to participate in a voluntary survey whose additional data, when linked to STS ACSD records, will better delineate contemporary beta blocker practice and outcomes.

Outcomes of Neonatal Cardiac Surgery: a European Congenital Heart Surgeons Association Study.

BACKGROUND: We evaluated outcomes of neonatal cardiac surgery at hospitals affiliated with the European Congenital Heart Surgeons Association (ECHSA). METHODS: All patients ≤30 days of life undergoing a cardiac surgical procedure during a 10 year period between January 2013 and December 2022 were selected from the ECHSA Congenital Database. Reoperations during the same hospitalization, percutaneous procedures, and noncardiac surgical procedures were excluded. A total of 12 benchmark operations were identified. Primary outcomes were 30-day mortality and in-hospital mortality. Multivariable logistic regression analysis was performed to determine independent factors associated with higher mortality. A comparison of mortality between the first 5 years and second 5 years was also performed. RESULTS: The overall number of neonatal operations from 2013-2022 was 30,931, and 22,763 patients met the inclusion criteria of the study. The four most common procedures were: arterial switch operation (3,520/22,763=15.5%), aortic coarctation repair (3,204/22,763=14.1%), shunt procedure (2,351/22,763=10.3%), and Norwood Operation (2,115/22,763=9.23%). 30-day mortality rate was: overall population (1,342/22,763=5.9%), arterial switch (110/3,520=3.13%), Norwood Operation (339/2,115=16.0%), and hybrid operation (94/609=15.4%). In-hospital mortality rate was: overall population (2,074/22,763=9.1%), arterial switch (145/3,520=4.12%), Norwood Operation (523/2,115=24.7%), and hybrid operation (186/609=30.5%). Multivariable analysis revealed that major factors impacting mortality were high risk procedures (adjusted odds ratio=2.74 [95% confidence interval=2.33-3.23]; p<0.001), and the need for extracorporeal membrane oxygenation (11.8 [9.9-14]; p <0.001). CONCLUSIONS: Neonatal cardiac surgery continues to pose a significant challenge, with notable mortality, particularly for neonates with functionally univentricular physiology. These data can serve as important benchmarks across Europe and offer insights regarding opportunities for improvement.

Outcomes in Children Who Undergo Post-cardiotomy ECMO: A Report from the STS-CHSD.

BACKGROUND: Children who undergo cardiac surgery may require post-cardiotomy extracorporeal membrane oxygenation (ECMO). Although morbidities are considerable, our understanding of outcome determinants is limited. We evaluated associations between patient and peri-operative factors with outcomes. METHODS: The STS Congenital Heart Surgery Database was queried for patients <18yo who underwent post-cardiotomy ECMO from 1/2016-6/2021. PRIMARY OUTCOME: survival to hospital discharge. SECONDARY OUTCOME: survival without neurologic injury. Logistic regression for binary outcomes and competing risk analysis for survival were used to identify the most important predictors. Variables were selected by stepwise procedure using entry level p=0.35. Those with p≤0.1 were kept in the final model. RESULTS: A total of 3,181 patients were supported with post-cardiotomy ECMO during the same hospitalization as cardiac surgery: (A) intra-operative initiation of ECMO, n=1206; (B) early post-operative (≤48 hours), n=936; (C) late post-operative (>48 hours), n=1039. Most common primary procedure of index operation was the Norwood procedure. 57% intra-op survived to discharge, versus 59% early post-op and 42% late post-op group (χ2 (2) = 64, p<0.0001, V = 0.14). In all groups, post-op septicemia, cardiac arrest, and new neurologic injury had the strongest association with mortality, while post-operative reintubation and unplanned non-cardiac reoperation were associated with higher survival. CONCLUSIONS: Multiple risk factors impact survival in children who undergo cardiac surgery and post-cardiotomy ECMO. ECMO initiated >48 hours after surgery is associated with the poorest outcomes. This is the first step in creating a predictive tool to educate clinicians and families regarding expectations in this high-risk population.

Worldwide application and valuation of extracorporeal membrane oxygenation support during the COVID-19 pandemic (WAVES).

OBJECTIVE: The outcomes of COVID-19 patients on venovenous extracorporeal membrane oxygenation (VV-ECMO) varied. We aim to investigate the variability concerning location and timeframe. We conducted a retrospective analysis of data from 351 institutions in 53 countries. The primary outcome was survival to hospital discharge or death up to 90 days from ECMO start. The associations between calendar time (month and year) of ECMO initiation and the primary outcome were examined by Cox regression modeling. Multivariable survival analyses were adjusted for the time of ECMO start, age, body mass index, APACHE II, SOFA, and the duration of mechanical ventilation before ECMO. RESULTS: 1060 adult COVID-19 patients enrolled in the COVID-19 Critical Care Consortium (COVID Critical) international registry and required VV-ECMO support. The study period is from January 2020 to December 2021. The median age was 51 years old, and 70% were male patients. Most patients were from Europe (39.3%) and North America (37.4%). The in-hospital mortality of the entire cohort was 47.12%. In North America and Europe, there was an increased probability of death from May 2020 through February 2021. Latin America showed a steady rate of survival until late in the study. South Asia, the Middle East, and Africa showed an increased chance of mortality around May 2020. In the Asian-Pacific region, after February 2021, there was an increased probability of death. The time of ECMO initiation and advanced patient age were associated with increased mortality. CONCLUSION: Variability in the outcomes of COVID-19 patients on VV-ECMO existed within different regions. This variability reflects the differences in resources, policies, patient selection, management, and possibly COVID-19 virus subtypes. Our findings might help guide global response in the future by early adoption of patient selection protocols, worldwide policies, and delivery of resources.

The Society of Thoracic Surgeons Clinical Practice Guidelines on the Management of Neonates and Infants with Coarctation.

BACKGROUND: Although coarctation of the aorta without concomitant intracardiac pathology is relatively common, there is lack of guidance regarding aspects of its management in neonates and infants. METHODS: A panel of experienced congenital cardiac surgeons, cardiologists, and intensivists was created, and key questions related to the management of isolated coarctation in neonates and infants were formed using the PICO (Patients/Population, Intervention, Comparison/Control, Outcome) Framework. A literature search was then performed for each question. Practice guidelines were developed with classification of recommendation and level of evidence using a modified Delphi method. RESULTS: For neonates and infants with isolated coarctation, surgery is indicated in the absence of obvious surgical contraindications. For patients with risk factors for surgery, medical management before intervention is reasonable. For those stable off prostaglandin E1, the threshold for intervention remains unclear. Thoracotomy is indicated when arch hypoplasia is not present. Sternotomy is preferable when arch hypoplasia is present that cannot be adequately addressed through a thoracotomy. Sternotomy may also be considered in the presence of a bovine aortic arch. Antegrade cerebral perfusion may be reasonable when the repair is performed through a sternotomy. Extended end-to-end, arch advancement, and patch augmentation are all reasonable techniques. CONCLUSIONS: Surgery remains the standard of care for the management of isolated coarctation in neonates and infants. Depending on degree and location, arch hypoplasia may require a sternotomy approach as opposed to a thoracotomy approach. Significant opportunities remain to better delineate management in these patients.

Reoperations in Adolescents and Adults After Prior Arterial Switch Operation: The Society of Thoracic Surgeons Congenital Heart Surgery Database Analysis.

BACKGROUND: Arterial switch operation (ASO) has supplanted physiologic repairs for transposition of the great arteries and related anomalies. As survival rates have increased, so has the potential need for cardiac reoperations to address ASO-related complications arising later in life. METHODS: The Society of Thoracic Surgeons Congenital Heart Surgery Database (2010-2021) was reviewed to assess prevalence and types of cardiac reoperations for patients aged ≥10 years with prior ASO for transposition of the great arteries or double-outlet right ventricle/transposition of the great arteries type. A hierarchical stratification designating 13 procedure categories was established a priori by investigators. Each eligible surgical hospitalization was assigned to the single highest applicable hierarchical category. Outcomes were compared across procedure categories, excluding hospitalizations limited to pacemaker-only and mechanical circulatory support-only procedures. Variation during the study period in relative proportions of left heart vs non-left heart procedure category encounters was assessed. RESULTS: There were 698 cardiac surgical hospitalizations for patients aged 10 to 35 years at 100 centers. The most common left heart procedure categories were aortic valve procedures (n = 146), aortic root procedures (n = 117), and coronary artery procedures (n = 40). Of 619 hospitalizations eligible for outcomes analysis, major complications occurred in 11% (67/619). Discharge mortality was 2.3% (14/619). Year-by-year analysis of surgical hospitalizations reveals substantial growth in numbers for the aggregate of all procedure categories. Growth in relative proportions of left heart vs non-left heart procedures was significant (P = .0029; Cochran-Armitage trend test). CONCLUSIONS: This large multicenter study of post-ASO reoperations beyond early childhood documents year-over-year growth in total reoperations. Left-sided heart procedures recently had the highest rate of rise. These observations have implications for counseling, surveillance, and management.

The 2023 Annual Report of DataDerm: The database of the American Academy of Dermatology.

The American Academy of Dermatology launched DataDerm in 2016 as the clinical data registry platform of American Academy of Dermatology. DataDerm has evolved to be the largest database in the world containing information about dermatology patients, capturing information about their course of disease, associated therapeutic interventions, and health outcomes. As of December 31, 2022, DataDerm contained data from 14.2 million unique patients and 53.5 million unique patient visits, with 415 practices representing 1663 clinicians actively participating in DataDerm in 2022. This article is the fourth in a series of Annual Reports about the status of DataDerm. This year's 2023 Annual Report presents the progress DataDerm has made in conjunction with OM1, the data analytics partner of DataDerm, with a special highlight on the longitudinal care of common dermatologic conditions in the registry and a detailed focus on skin cancer. Furthermore, we review the current status of DataDerm as a robust representation of real world specialty data, reflecting the day-to-day dermatologic care of patients over time.

Risk of Cardiac Reoperation: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database.

BACKGROUND: The increasing number of congenital heart disease patients undergoing reoperative cardiac surgery presents critical and growing challenges. Our objective was to evaluate the association between the number of prior cardiopulmonary bypass operations and operative mortality and morbidity in a national cohort. METHODS: The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) was reviewed for index cardiac operations on cardiopulmonary bypass during 2016 to 2021. Infants and patients with functionally univentricular physiology were excluded. Multivariable logistic regression adjusted for covariates in the STS-CHSD Mortality Risk Model, the STS-European Association for Cardio-Thoracic Surgery (STAT) Mortality Category, and institutional volume. RESULTS: Of 50,625 eligible operations, 22,100 (44%) were performed on patients with ≥1 prior cardiopulmonary bypass operations. Most common diagnoses were tetralogy of Fallot (4340 of 22,100 [19.6%]), pulmonary atresia/ventricular septal defect (1334 of 22,100 [6.0%]), and aortic stenosis (966 of 22,100 [4.4%]). Operative mortality correlated with number of prior cardiopulmonary bypass operations: 157 of 28,525 (0.6%) for 0, 127 of 13,488 (0.9%) for 1, 81 of 5,664 (1.4%) for 2, 61 of 2039 (3.0%) for 3, 35 of 623 (5.6%) for 4, 10 of 207 (4.8%) for 5, and 5 of 79 (6.3%) for ≥6 operations (P < .001). On multivariable analysis, patients with ≥3 prior cardiopulmonary bypass operations had higher risk of operative mortality (odds ratio, 2.31; P < .001) and major morbidity (odds ratio, 1.60; P < .001). Annual institutional volume and age were not associated with either outcome. CONCLUSIONS: Three or more prior cardiopulmonary bypass operations was an independent risk factor for operative mortality/morbidity, even after controlling for risk factors and institutional volume. Future research is needed to identify modifiable factors to optimize outcomes, particularly for those with ≥3 prior cardiopulmonary bypass operations.

Combined en bloc heart and liver organ procurement.

A combined heart+liver transplant is the only option for survival in some patients with end-stage combined cardiac and hepatic disease. These patients may suffer from congenital or acquired cardiac disease. The potential aetiologies of the associated hepatic disease are heterogeneous and include systemic disease that impacts the liver as well as venous congestion in patients with functionally univentricular circulation. In the latter scenario, patients with functionally univentricular circulation often require complex cardiac reconstruction in the setting of a cardiac transplant after staged palliation. During cardiac procurement, our approach is to dissect the entire ascending aorta and aortic arch in continuity; the entire superior caval vein and innominate vein in continuity; and the pulmonary arteries from hilum to hilum if the donor is not a candidate for recovery of the lungs. The cardiac and abdominal organ procurement teams work in parallel during dissection and combined en bloc cardio-hepatectomy. This technique minimizes exposure of both organs to cold ischaemia. This video tutorial demonstrates the key steps for combined en bloc heart+liver organ procurement.

Pediatric Heart Transplantation Over 36 Years and Contemporary Volume-Outcome Analysis of UNOS.

BACKGROUND: This study examines 36 years of national pediatric heart transplantation data to 1) identify trends in transplant volume, centers, and one-year graft survival, and 2) assess how center transplant volume impacts outcomes over a contemporary 11-year period. METHODS: We performed a retrospective review of pediatric patients (<18 years) undergoing heart transplantation from 1/1/1987 to 12/31/2022 using the United Network for Organ Sharing Database. Trend analyses included the whole cohort, while volume-outcome analyses included a contemporary cohort to account for the temporal changes observed in transplant survival. Highest volume centers were defined by the number of heart transplants performed per center per year. RESULTS: Over 36 years, 11,828 pediatric heart transplants were performed. Transplant volume steadily rose, the number of centers remained stable, and one-year graft survival has improved significantly. In the contemporary era (2012-2022), 89 centers conducted 4,959 pediatric heart transplants. The top 15% high-volume centers (13 centers) accounted for 48.3% (2,393) of transplants, with an average of 16.7±3.8 transplants per center annually, compared to 3.9±3.1 for lower volume centers. Despite transplanting higher risk patients, high-volume centers had similar postoperative outcomes and improved long-term survival. CONCLUSIONS: While the number of US pediatric heart transplant centers has remained stable, pediatric heart transplant volume is steadily increasing, as is one-year graft survival. In a contemporary cohort, the top 15th percentile highest volume centers accounted for 48.3% of US pediatric heart transplants and transplanted higher risk patients with similar postoperative outcomes and improved longitudinal survival.

Outcomes of Isolated Tricuspid Valve Surgery: A Society of Thoracic Surgeons Analysis and Risk Model.

BACKGROUND: To provide patients and surgeons with clinically relevant information, The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database was queried to develop a risk model for isolated tricuspid valve (TV) operations. METHODS: All patients in the STS Adult Cardiac Surgery Database who had undergone isolated TV repair or replacement (N = 13,587; age 48.3 ± 18.4 years) were identified (July 2017 to June 2023). Multivariable logistic regression accounting for TV replacement vs repair was used to model 8 operative outcomes: mortality, morbidity or mortality or both, stroke, renal failure, reoperation, prolonged ventilation, short hospital stay, and prolonged hospital stay. Model discrimination (C-statistic) and calibration were assessed using 9-fold cross-validation. RESULTS: The isolated TV study population included 41.1% repairs (N = 5,583; age 52.6 ± 18.1 years) and 58.9% replacements (N = 8,004; age 45.3 ± 18.0 years). The overall predicted risk of operative mortality was 5.6%, and it was similar in TV repairs and replacements (5.5% and 5.7%, respectively), as was the predicted risk of composite morbidity and mortality (28.2% and 26.8%). TV replacements were generally performed in younger patients with a higher endocarditis prevalence than TV repairs (45.7% vs 21.1%). The model yielded a C-statistic of 0.81 for mortality and 0.76 for the composite of morbidity and mortality, with excellent observed-to-expected calibration that was comparable in all subcohorts and predicted risk decile groups. CONCLUSIONS: An STS risk model has been developed for isolated TV surgery. The current mortality of isolated TV operations is lower than previously observed. This risk prediction model and these contemporary outcomes provide a new benchmark for current and future isolated TV interventions.

Ruptured Sinus of Valsalva Aneurysm: Three Case Reports and Literature Review.

Sinus of Valsalva aneurysm rupture (SOVAR) into the right cardiac chambers is an uncommon complication with unusual presentation, high morbidity and mortality, and unique hemodynamics as well as cardiac imaging findings. Here, we present three SOVAR cases (two with rupture into the right atrium and one with rupture into the right ventricle) that were initially confused for ventricular septal defects and describe their initial presentation, cardiac imaging studies, invasive hemodynamics, as well as treatment options. Some of the unique findings of SOVAR patients include an acute presentation, often with hemodynamic decompensation, the presence of a continuous murmur on examination, and also hemodynamics that include wide pulse pressure and right heart volume overload.

Predicting Stroke for Pediatric Patients Supported With Ventricular Assist Devices: A Pedimacs Report.

BACKGROUND: The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) provides detailed understanding on pediatric patients supported with ventricular assist devices (VADs). We sought to identify important variables affecting the incidence of stroke in pediatric VADs. METHODS: Between 2012 and 2022, 1463 devices in 1219 patients were reported to Pedimacs from 40 centers in patients aged <19 years at their first VAD implantation. Multiphase parametric hazard modeling was used to identify risk factors for stroke among all device types. RESULTS: Of the 1219 patients, the most common devices were implantable continuous (472 [39%]), followed by paracorporeal pulsatile (342 [28%]), and paracorporeal continuous (327 [27%]). Overall freedom from stroke at 6 months was higher in the recent era (2012-2016; 80.2% [95% CI, 77.1%-82.9%] vs 2017-2023; 87.9% [95% CI, 86.2%-89.4%], P = .009). Implantable continuous VADs had the highest freedom from stroke at 3 months (92.7%; 95% CI, 91.1%-93.9%) and 6 months (91.1%; 95% CI, 89.3%-92.6%), followed by paracorporeal pulsatile (87.0% [95% CI, 84.8%-88.9%] and 82.8% [95% CI, 79.8%-85.5%], respectively), and paracorporeal continuous (76.0% [95% CI, 71.8%-79.5%] and 69.5% [95% CI, 63.4%-74.8%], respectively) VADs. Parametric modeling identified risk factors for stoke early after implant and later. Overall, and particularly for paracorporeal pulsatile devices, early stroke risk has decreased in the most recent era (hazard ratio, 5.01). Among implantable continuous devices, cardiogenic shock was the major risk factor. For patients <10 kg, early hazard was only seen in the previous era. For congenital patients, early hazard was seen in nonimplantable device use and use of extracorporeal membrane oxygenation. CONCLUSIONS: The overall stroke rate has decreased from 20% to 15% at 6 months, with particular improvement among paracorporeal pulsatile devices. Risk factor analyses offer insights for identification of higher stroke risk subsets and further management refinements.

15-Year Analysis of Surgical Approaches and Outcomes for Coarctation in 132 Neonates and Infants.

A variety of surgical approaches exist to treat aortic coarctation in neonates and infants. Our institutional approach is designed to match the surgical approach to the individual anatomy of the patient. The objective of this study is to evaluate operative characteristics and outcomes of all neonates and infants who underwent surgical repair of coarctation of the aorta or hypoplastic aortic arch at University of Florida from 2006 to 2021, inclusive, either in isolation or with concomitant repair of atrial septal defect (ASD) and/or ventricular septal defect (VSD). A retrospective review was performed of 132 patients aged 0-1 year who underwent surgical repair of aortic coarctation or hypoplastic aortic arch between 2006 and 2021, inclusive, either in isolation or with concomitant repair of ASD and/or VSD. Patients were divided into two groups based on the surgical approach: Group 1 = Median Sternotomy and Group 2 = Left Lateral Thoracotomy. Continuous variables are presented as median (minimum-maximum); categorical variables are presented as N (%). The most common operative technique in Group 1 was end-to-side reconstruction with ligation of the aortic isthmus. The most common operative technique in Group 2 was extended end-to-end repair. Operative Mortality was one patient (1/132 = 0.76%). Transcatheter intervention for recurrent coarctation was performed in seven patients (7/132 = 5.3%). Surgical re-intervention for recurrent coarctation was performed in three patients (3/132 = 2.3%). From these data, one can conclude that a strategy of matching the surgical approach to the anatomy of neonates and infants who underwent surgical repair of aortic coarctation or hypoplastic aortic arch, either in isolation or with concomitant repair of ASD and/or VSD, is associated with less than 1% Operative Mortality and less than 3% recurrent coarctation requiring reoperation.

Effect of geography on the use of ultrafiltration during cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Ultrafiltration (UF) is a common practice during cardiopulmonary bypass (CPB) where it is used as a blood management strategy to reduce red blood cell (RBC) transfusion, minimize adverse effects of hemodilution, and reduce proinflammatory mediators. However, its clinical utilization has been shown to vary throughout the continents. PURPOSE: The purpose of this investigation was to assess the distribution of UF use across the United States. DATA COLLECTION: Data on UF use during cardiac surgery was obtained from a national (United States) perfusion database for adult cardiac procedures performed from January 2016 through December 2018. STUDY SAMPLE: Four geographical regions were established: Northeast (NE), South (SO), Midwest (MW) and West (WE). The primary endpoint was the use of UF with secondary endpoints UF volume, CPB and anesthesia asanguineous volumes, intraoperative allogeneic RBC transfusion, nadir hematocrit and urine output (UO). 92,859 adult cardiac cases from 191 hospitals were reviewed. RESULTS: The NE and the WE had similar usages of UF (59.9% and 59.7% respectively), which were higher than the MW and the SO (38.6% and 34.9%, p < .001). When UF was utilized, the median [IQR] volume removed was highest in the NE (1900 [1200-2800]mL), and similar in all other regions (WE 1500 [850-2400 mL, MW 1500 [900-2300]mL and SO 1500 [950-2200]mL, p < .001. Median total UO was lowest in the NE 400 [210,650]mL vs all other regions (p < .001), and remained so when indexed by patient weight and operative time (NE-0.8 [0.5, 1.3]mL/kg/hour, MW-1.1 [0.7, 1.8] mL/kg/hour, SO-1.3 [0.8, 2.0]mL/kg/hour, WE-1.1 [0.7, 1.3]mL/kg/hour, p < .001. Intraoperative RBC transfusion rate was highest in the SO (21.3%) and WE (20.5%), while similar rates seen in the NE (16.2%) and MW (17.6%), p < .001. CONCLUSIONS: Across the United States there is geographic variation on the use of UF. Further research is warranted to investigate why these practice variations exist and to better understand and determine their reasons for use.

The safe addition of nitric oxide to the sweep gas of the extracorporeal membrane oxygenation circuit in a pediatric cardiac intensive care unit.

Background: Nitric Oxide (NO) is a naturally occurring modulator of inflammation found in the human body. Several studies in the pediatric cardiothoracic surgery literature have demonstrated some beneficial clinical effects when NO is added to the sweep gas of the cardiopulmonary bypass circuit.Purpose: Our primary aim was to determine the safety of incorporating nitric oxide into the oxygenator sweep gas of the extracorporeal membrane oxygenation (ECMO) circuit. Secondarily, we looked at important clinical outcomes, such as survival, blood product utilization, and common complications related to ECMO.Methods: We performed a single center, retrospective review of all patients at our institution who received ECMO between January 1, 2017 and March 31, 2023. We began additing NO to the ECMO sweep gas in 2019. Results: There were no instances of clinically significant methemoglobinemia with the addition of NO to the sweep gas (0% vs 0%, p = 1). The median daily methemoglobin level was higher in those who received NO via the sweep gas when compared to those who did not (1.6 vs 1.1, p = <0.001). Conclusions: The addition of NO to the sweep gas of the ECMO circuit is safe.

Cardiology across continents: an interactive, case-based learning series.

Heart University [https://www.heartuniversity.org/] is a free educational website providing structured training curricula with knowledge-based testing and access to webinars and conference recordings for practicing and in-training providers of paediatric and congenital cardiac care. To date, there are over 15,000 registered website users from over 140 countries on Heart University, with over 2,000 training modules and/or recorded educational videos. Heart University has developed an "asynchronous" educational lecture series entitled "Pediatric and Congenital Cardiac Care in Resource-Limited Settings." This recorded lecture series is specifically focused on topics relevant to practicing paediatric and/or congenital cardiac care in low-resource settings.A relatively new initiative, "Cardiology Across Continents," supplements the existing educational resources for providers of paediatric and/or congenital cardiac care in low-income countries and lower-middle-income countries by providing an additional live, interactive, case-based forum. Sessions occur every 1-2 months and focus on challenging cases from diagnostic or management perspective with a view to promote collaboration between partnered institutions. "Cardiology Across Continents" is an expanding initiative that facilitates learning and collaboration between clinicians across varied practice settings via interactive case discussions. We welcome trainees and providers of paediatric and congenital cardiac care to join the sessions and invite any insight that can enhance learning for clinicians around the world. This manuscript describes "Cardiology Across Continents" and discusses the development, history, current status, and future plans of Heart University.