RESEARCH EXPLAINED
Since October 2013, Research Explained has been an ongoing collaboration between parents of individuals with SVHD and clinicians to make single ventricle medical research easier to understand. Members of the SV-ONE Research Explained subcommittee help identify manuscripts that are of interest to families for creation of a “Research Explained” summary. These summaries use straightforward terms to explain the purpose of the research study and significance of the findings.
If you have any questions about Research Explained, please contact info@svone.org.
OUR LATEST SUMMARY
Trends and Regional Disparities in Hypoplastic Left Heart Syndrome Prevalence and Mortality in the USA: A Nationwide Study (2026)
Prepared By:
Matthew Moehlmann, DO (physician), Marie-Jo Herard Furey (parent), and Autumn Jones (parent)
This study used 15 years of publicly available U.S. birth and death records to examine first-year outcomes among infants with hypoplastic left heart syndrome (HLHS), including how these outcomes have changed over time and varied by race, sex, or state.
Research Article Used: Mantena, J., & Vidavalur, R. (2026). Trends and regional disparities in hypoplastic left heart syndrome prevalence and mortality in the USA: A nationwide study. European Journal of Pediatrics, 185, Article 493. //doi.org/10.1007/s00431-026-07165-1
Fetal
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Matthew Moehlmann DO (physician) and Colleen Melchiorre Ed.D. (parent)
Prenatal counseling can vary between different providers.
The authors of this study wanted to know if pediatric cardiology providers’ beliefs impacted how they talk about congenital heart disease (CHD) with pregnant mothers and how they share different options for care with those families.
Research article used:
Evaluating How Beliefs Among Pediatric Cardiology Providers May Affect Fetal Cardiac Counseling-A National Perspective
Haxel CS, Ronai C, Martens AM, Lim CC, Pinto N, Chiu JS. Evaluating How Beliefs Among Pediatric Cardiology Providers May Affect Fetal Cardiac Counseling-A National Perspective. Prenat Diagn. 2025 Jun;45(6):752-763. doi: 10.1002/pd.6706. Epub 2024 Nov 29. PMID: 39613724.
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Item descriptionKatelyn Y. Legaspi, MD (physician), Jennifer Co-Vu, MD (physician), and Nicole Sage (parent)
This study analyzed maternal and fetal comorbidities and outcomes in pregnancies with single ventricle cardiac defects (SVCD) of either hypoplastic left heart (HLHS) or hypoplastic right heart (HRH) that were cared for over the span of 10 years (2013-2022) at the Children’s Hospital Colorado Fetal Care Center using their multidisciplinary protocol.
Research Article Used: Wautlet CK, Kops SA, Silveira LJ, et al. Maternal-fetal comorbidities and obstetrical outcomes of fetal single ventricle cardiac defects: 10 years' experience with a multidisciplinary management protocol at a single center. Prenat Diagn. 2024; 44(6-7): 783-795. https://doi.org/10.1002/pd.6591
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Prepared by: Shannon Bilsky RN (nurse), Sarah Plummer MD (physician), and Colleen Coffey (parent)
The goal of this study was to explore whether the size of the brain before birth (fetal brain volume) could predict how children with congenital heart disease (CHD) would do developmentally after birth.
Research Article Used:
Sadhwani A, Wypij D, Rofeberg V, Gholipour A, Mittleman M, Rohde J, et al. Fetal Brain Volume Predicts Neurodevelopment in Congenital Heart Disease. Circulation. 2022 Apr 12;145(15):1108–19.
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Over the past several decades there has been dramatic improvement in surgical survival in infants born with HLHS. However, ~20% of infants born with HLHS still die within the first months of life. This study attempts to identify risk factors that we might be able to address to improve this survival.
Research Article Used:
Morris SA, Ethen MK, Penny DJ, Canfield MA, Minard CG, Fixler DE, et al. Prenatal Diagnosis, Birth Location, Surgical Center, and Neonatal Mortality in Infants With Hypoplastic Left Heart Syndrome. Circulation. 2014 Jan 21;129(3):285–92.
Neonatal
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Background Feeding dysfunction occurs commonly in infants with single ventricle heart disease and impacts growth and long-term outcomes. This study surveyed centers participating in the National Pediatric Cardiology Quality Improvement Collaborative to assess prevailing feeding practices among those caring for single ventricle neonates.
Research Article Used:
Slicker J, Sables-Baus S, Lambert LM, Peterson LE, Woodard FK, Ocampo EC. Perioperative Feeding Approaches in Single Ventricle Infants: A Survey of 46 Centers. Congenital Heart Disease. 2016 Jul 13;11(6):707–15.
Stage 1
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Prepared by: Matthew Moehlmann, DO (physician), Marie-Jo Herard Furey (parent), and Autumn Jones (parent)
This study used 15 years of publicly available U.S. birth and death records to track how often babies with hypoplastic left heart syndrome (HLHS) die in their first year of life, and how that has changed over time or differs by race, sex, or state.
Research Article Used: Mantena, J., & Vidavalur, R. (2026). Trends and regional disparities in hypoplastic left heart syndrome prevalence and mortality in the USA: A nationwide study. European Journal of Pediatrics, 185, Article 493. https://doi.org/10.1007/s00431-026-07165-1
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Prepared by: Reilly Hobbs (physician) and Richard James (parent)
This study looked at the survival and other outcomes of children after the Norwood operation according to the average number of Norwood procedures performed each year. The study found that there was no difference between what patients looked like and in how sick they were before surgery. There was no difference in 30-day mortality based on how many surgeries a year the hospital did. However, babies who had surgery at hospitals that treated more patients a year were much more likely to be alive at their first birthday. This advantage was even better for patients with high-risk features, such as low birth weight, genetic diagnosis, ventricular dysfunction, and valvular regurgitation.
Research Article Used:
Schäfer, M., McFarland, C., Amula, V., Truong, D., Lambert, L. M., Griffiths, E. R., Eckhauser, A. W., Husain, S. A., & Hobbs, R. D. (2025). Volume-Outcome Relationship of Norwood Procedures: Insights from the National Pediatric Cardiology-Quality Improvement Collaborative Database. The Annals of thoracic surgery, S0003-4975(25)00071-2. Advance online publication. https://doi.org/10.1016/j.athoracsur.2025.01.007
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Christopher Curzon, DO (physician), and Steven Matthies (parent)
The goal of this study is to evaluate a less invasive palliative procedure for high-risk infants as an alternative to a surgical procedure during the neonatal period.
Research Article Used: Francesca Sperotto, MD, PhD, Nora Lang, MD, PhD, Meena Nathan, MD, MPH, Aditya Kaza, MD, David M. Hoganson, MD, Eleonore Valencia, MD, Kirsten Odegard, MD, Catherine K. Allan, MD, Eduardo M. da Cruz, MD, Pedro J. Del Nido, MD, Sitaram M. Emani, MD, Christopher Baird, MD, Nicola Maschietto, MD, PhD. Transcatheter Palliation With Pulmonary Artery Flow Restrictors in Neonates With Congenital Heart Disease: Feasibility, Outcomes, and Comparison With a Historical Hybrid Stage 1 Cohort
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Research Explained: Predictors and Outcomes of Arrhythmia on Stage I Palliation of Single Ventricle Patients
Richard Czosek (physician) and Nicole Sage (parent)
The goal of this study was To describe risks for arrhythmias in patients having the first stage surgery for single ventricle disease and describe outcomes and treatment strategies.
Research Article Used:
Czosek RJ, Spar DS, Anderson JB, Khoury PR, Webster G. Predictors and Outcomes of Arrhythmia on Stage I Palliation of Single Ventricle Patients. JACC Clinical electrophysiology [Internet]. 2022 Sep 1 [cited 2022 Dec 6];8(9):1136–44. Available from: https://pubmed.ncbi.nlm.nih.gov/36137719/
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Sinai C. Zyblewski (physician) and Richard James (parent)
This study shows that infants with single ventricle physiology grow better and are less likely to get NEC when they are fed with only human milk (breast milk) after their first surgery.
Research Article Used:
Blanco C, Hair A, Justice LB, Roddy D, Bonagurio K, Williams PK, et al. A Randomized Trial of an Exclusive Human Milk Diet in Neonates with Single Ventricle Physiology. The Journal of Pediatrics [Internet]. 2022 Dec 14 [cited 2023 Feb 2];S0022-3476(22)01126X. Available from: https://pubmed.ncbi.nlm.nih.gov/36528055/
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Many children with HLHS who undergo SVP do well. Unfortunately, however, many babies and children do not survive SVP and others have medical problems related to the heart and other organs. This study describes ways of getting the left ventricle to grow; they call this “staged left ventricular recruitment”, or SLVR.
Research Article Used:
Emani SM, McElhinney DB, Tworetzky W, Myers PO, Schroeder B, Zurakowski D, et al. Staged left ventricular recruitment after single-ventricle palliation in patients with borderline left heart hypoplasia. Journal of the American College of Cardiology [Internet]. 2012 Nov 6;60(19):1966–74. Available from: https://pubmed.ncbi.nlm.nih.gov/23062531/
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While there has been great improvement in care for patients with hypoplastic left heart syndrome and other similar single ventricle lesions that require the Norwood procedure, these patients are still at great risk. This study describes a comparison of two groups who were randomly assigned to get one shunt type or the other at the time of their Norwood surgery.
Research Article Used:
Ohye RG, Sleeper LA, Mahony L, Newburger JW, Pearson GD, Lu M, et al. Comparison of Shunt Types in the Norwood Procedure for Single-Ventricle Lesions. New England Journal of Medicine. 2010 May 27;362(21):1980–92.
Interstage 1
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Richard James (parent) and Benjamin Zielonka, MD (physician)
This study examined the relationship between childhood opportunity (a composite measure of social disparities) and outcomes after the stage 1 operation among infants in the National Pediatric Cardiology Quality Improvement Collaborative phase 2 registry.
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Kristin Elgersma (PhD) and Richard James (parent)
There have not been very many studies about human milk/BF for infants with single ventricle CHD. This study reports rates of human milk and BF for infants with single ventricle CHD who received care at NPC-QIC sites, and looked at whether infants who are directly BF at stage 1 discharge are more likely to still be receiving human milk (by any route) at stage 2 palliation. This is the largest study yet about human milk/BF for infants with any type of CHD.
Research Article Used:
Elgersma KM, Spatz DL, Fulkerson JA, Wolfson J, Georgieff MK, Looman WS, et al. Patterns of Breastfeeding and Human Milk Feeding in Infants with Single-Ventricle Congenital Heart Disease: A Population Study of the National Pediatric Cardiology Quality Improvement Collaborative Registry. Breastfeeding Medicine. 2023 Apr 1;18(4):315–25.
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Matthew Moehlmann DO (physician) and Dawn Mazzanti (parent)
The interstage period is a high risk time for death for children that require staged surgical palliation. The factors that cause interstage death or need for heart transplantation are not well understood and this study looks at different factors that might predict interstage death.
Research Article Used:
Ahmed H, Anderson JB, Bates KE, Fleishman CE, Natarajan S, Ghanayem NS, et al. Development of a validated risk score for interstage death or transplant after stage I palliation for single-ventricle heart disease. The Journal of Thoracic and Cardiovascular Surgery [Internet]. 2020 Oct 1;160(4):1021–30. Available from: https://pubmed.ncbi.nlm.nih.gov/31924360/
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Necrotizing enterocolitis (NEC), infection/inflammation of the intestines, is a wellknown complication for infants with single ventricle physiology during their initial hospitalization when they undergo their first staged surgical procedure. The goal of this study was to compare the midterm outcomes during the interstage period for infants with hypoplastic left heart syndrome who had survived to hospital discharge that developed NEC (HLHS-NEC) versus those that did not develop NEC (HLHS-nNEC) during their initial hospitalization.
Research Article Used:
Lopez NL, Gowda C, Backes CH, Nandi D, Miller-Tate H, Fichtner S, et al. Differences in midterm outcomes in infants with hypoplastic left heart syndrome diagnosed with necrotizing enterocolitis: NPCQIC database analysis. Congenital Heart Disease. 2018 Mar 9;13(4):512–8.
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Sinai C. Zyblewski MD (physician) and Richard James (parent)
The study looked at single ventricle heart disease with narrowing of the main artery where it leaves the heart (aortic arch hypoplasia), and how it has high risk for medical complications and early death; many of the problems associated with this often need to be fixed with either catheter-based procedures or more surgery.
Research Article Used:
Buelow MW, Rudd N, Tanem J, Simpson P, Bartz P, Hill G. Reintervention following stage 1 palliation: A report from the NPC-QIC Registry. Congenital Heart Disease. 2018 Aug 10;13(6):919–26.
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Although interstage mortality for infants with hypoplastic left heart syndrome has declined within the National Pediatric Cardiology Quality Improvement Collaborative, variation across centers persists. The study examined previously established risk factors across National Pediatric Cardiology Quality Improvement Collaborative centers with lower and higher interstage mortality rates.
Research Article Used:
Bates KE, Yu S, Lowery R, Pasquali SK, Brown DW, Manning PB, et al. Examining variation in interstage mortality rates across the National Pediatric Cardiology Quality Improvement Collaborative: do lower-mortality centres have lower-risk patients? Cardiology in the Young. 2018 Jun 21;28(8):1031–6.
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Low birth and operative weight have been identified as risk factors for death after first-stage single-ventricle palliation. This study concluded that after first-stage single-ventricle palliation, interstage weight gain is significantly associated with transplant-free interstage survival.
Research Article Used:
Evans CF, Sorkin JD, Abraham DS, Wehman B, Kaushal S, Rosenthal GL. Interstage Weight Gain Is Associated With Survival After First-Stage Single-Ventricle Palliation. The Annals of Thoracic Surgery. 2017 Aug;104(2):674–80.
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Waldemar Carlo MD (physician) and Anne Dee Weisdorfer (parent)
the findings in the study can be viewed as most common practices in the field of HLHS palliation. This may help centers that are smaller, new to HLHS surgery, or have suboptimal results. Likewise, this same information can help families compare their own experiences to others and find comfort knowing standards are forming between centers.
Research Article Used:
Carlo WF, Cnota JF, Dabal RJ, Anderson JB. Practice trends over time in the care of infants with hypoplastic left heart syndrome: A report from the National Pediatric Cardiology Quality Improvement Collaborative. Congenital Heart Disease. 2017 Jan 25;12(3):315–21.
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For infants with single-ventricle lesions with aortic arch hypoplasia, the interstage period from discharge following stage 1 palliation (S1P) until stage 2 palliation (S2P) remains high risk. Significant variability among institutions exists around the timing of S2P. This study sought to describe institutional variation in timing of S2P, determine the association between timing of S2P and interstage mortality, and determine the impact of earlier S2P on hospital morbidity and mortality.
Research Article Used:
Hill GD, Rudd NA, Ghanayem NS, Hehir DA, Bartz PJ. Center Variability in Timing of Stage 2 Palliation and Association with Interstage Mortality: A Report from the National Pediatric Cardiology Quality Improvement Collaborative. Pediatric Cardiology. 2016 Aug 24;37(8):1516–24.
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Interstage mortality (IM) remains significant after stage 1 palliation (S1P) for single-ventricle heart disease (SVD), with many deaths sudden and unexpected. This study sought to determine whether digoxin use post-S1P is associated with reduced IM, utilizing the multicenter database of the National Pediatric Cardiology Quality Improvement Collaborative (NPCQIC).
Research Article Used:
Brown DW, Mangeot C, Anderson JB, Peterson LE, King EC, Lihn SL, et al. Digoxin Use Is Associated With Reduced Interstage Mortality in Patients With No History of Arrhythmia After Stage I Palliation for Single Ventricle Heart Disease. Journal of the American Heart Association. 2016 Jan 13;5(1).
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This study describes unanticipated interstage readmissions in patients with hypoplastic left heart syndrome, identifies independent risk factors for unanticipated interstage readmissions, and evaluates variation in unanticipated readmission rates among collaborative centers.
Research Article Used:
Hanke SP, Joy B, Riddle E, Ravishankar C, Peterson LE, King E, et al. Risk Factors for Unanticipated Readmissions During the Interstage: A Report From the National Pediatric Cardiology Quality Improvement Collaborative. Seminars in Thoracic and Cardiovascular Surgery [Internet]. 2016;28(4):803–14. Available from: https://pubmed.ncbi.nlm.nih.gov/28417868/
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While the authors of this study did not find a strong association between the recommended frequency of measuring saturations and weights and improvements in interstage mortality rates, it does not mean that these programs are not beneficial. It means that we still are not sure which interventions are the key ones and may not be appreciating how complicated interstage programs are to evaluate.
Research Article Used:
Pasquali SK. Reexamining Interstage Home Monitoring After the Norwood Operation. Circulation. 2015 Aug 11;132(6):475–8.
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Infants with hypoplastic left heart syndrome after the Norwood procedure are known to be at risk for poor growth, and our understanding of what specific practices are important to improve growth has advanced.
Research Article Used:
Patel MD, Uzark K, Yu S, Donohue J, Pasquali SK, Schidlow D, et al. Site of interstage outpatient care and growth after the Norwood operation. Cardiology in the Young. 2015 Jan 2;25(7):1340–7.
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Infants with hypoplastic left heart syndrome after the Norwood procedure are known to be at risk for poor growth, and our understanding of what specific practices are important to improve growth has advanced.
Research Article Used:
Schidlow DN, Gauvreau K, Patel M, Uzark K, Brown DW. Site of interstage care, resource utilization, and interstage mortality: a report from the NPC-QIC registry. Pediatric Cardiology [Internet]. 2015 Jan 1;36(1):126–31. Available from: https://pubmed.ncbi.nlm.nih.gov/25107545/
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This study is important because it is the first study to use information from many hospitals to evaluate home monitoring.
Research Article Used:
Oster ME, Ehrlich A, King E, Petit CJ, Clabby M, Smith S, et al. Association of Interstage Home Monitoring With Mortality, Readmissions, and Weight Gain: A Multicenter Study from the National Pediatric Cardiology Quality Improvement Collaborative. Circulation [Internet]. 2015 Aug 11;132(6):502–8. Available from: https://pubmed.ncbi.nlm.nih.gov/26260497/
Stage 2
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Dr. Jason Williams (physician) and Steven Matthies (parent)
This study evaluated differences in treatment timing, pre-surgical data, short-term outcome, and long-term outcome between Black and White patients with single ventricle physiology at Children’s Healthcare of Atlanta.
Research Article Used: Beshish, A. G., Adamson, M., Brady, M., Menon, A., Qian, J., Golloshi, K., Cote, O., Gathoo, A., Zinyandu, T., Nayi, P., Ferguson, M. E., John, M., Shaw, F. R., Deshpande, S. R., & Maher, K. O. (2025). Racial disparities in timing and outcomes for patients undergoing staged single ventricle palliation: a single institution report. Cardiology in the young, 35(2), 303–310. https://doi.org/10.1017/S1047951124026726
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Steven Matthies (parent) and Jason Williams MD (physician)
This study examines clinical outcomes in patients with borderline hypoplastic left heart deemed suitable for biventricular conversion from initial single ventricle palliation. Examining outcomes will help refine which patients are favorable candidates for biventricular recruitment and conversion.
Research Article Used:
Beattie MJ, Sleeper LA, Lu M, Teele SA, Breitbart RE, Esch JJ, et al. Factors associated with morbidity, mortality, and hemodynamic failure after biventricular conversion in borderline hypoplastic left hearts. The Journal of Thoracic and Cardiovascular Surgery [Internet]. 2023 Jan 23; S0022-5223(23)000867. Available from: https://pubmed.ncbi.nlm.nih.gov/36803549/
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Matthew Moehlmann DO (physician) and Richard James (parent)
Children with a functional single ventricle heart disease such as Hypoplastic Left Heart Syndrome need more energy from food in the “interstage period” between their first and second surgeries. We do not know if the way in which children are fed makes any difference to how long they stay in hospital, or if the way in which a child is fed changes during their stay; this study helped find out if these things did make a difference.
Research Article Used:
Hoch JM, Fatusin O, Yenokyan G, Thompson WR, Lefton‐Greif MA. Feeding methods for infants with single ventricle physiology are associated with length of stay during stage 2 surgery hospitalization. Congenital Heart Disease. 2019 Jan 12;14(3):438–45.
Interstage 2
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Prepared By: Lydia Wright, MD (physician) andNicole Sage (parent)
This study examined how often infants with single ventricle heart disease were referred for heart transplant in their first year of life, and whether race or neighborhood affected who received a referral.
Research Article Used:
Single Ventricle Infant Deaths without Transplant Referral: Room for Improvement?
Wright LK, Cabrera AG, Carrillo SA, Cua CL, Davis JA, Shustak RJ, Texter K, Nandi D.
Wright, L.K., Cabrera, A.G., Carrillo, S.A. et al. Single Ventricle Infant Deaths Without Transplant Referral: Room for Improvement?. Pediatr Cardiol (2026). https://doi.org/10.1007/s00246-026-04309-w
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Clifford Cua MD (physician) and Caleb Lihn (parent)
The article demonstrates that a better understanding of the risk factors contributing to death between the period from the SCPC to the Fontan surgery may be helpful in decreasing deaths during this time interval.
Research Article Used:
Lawrence KM, Ittenbach RF, Hunt ML, Kaplinski M, Ravishankar C, Rychik J, et al. Attrition between the superior cavopulmonary connection and the Fontan procedure in hypoplastic left heart syndrome. The Journal of Thoracic and Cardiovascular Surgery. 2021 Aug;162(2):385–93.
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Sinai C. Zyblewski MD (physician) and Dawn Mazzanti (parent)
Patients with hypoplastic left heart syndrome (HLHS) and its variants following palliation surgery are at risk for thrombosis. This study examines variability of antithrombotic practice, the incidence of interstage shunt thrombosis, and other adverse events following Stage I and Stage II palliation within the National Pediatric Cardiology Quality Improvement Collaborative registry.
Research Article Used:
Ramachandran P, King E, Nebbia A, Beekman RH, Anderson JB. Variability of antithrombotics use in patients with hypoplastic left heart syndrome and its variants following first- and second-stage palliation surgery: a national report using the National Pediatric Cardiology Quality Improvement Collaborative registry. Cardiology in the Young [Internet]. 2017 May 1;27(4):731–8. Available from: https://pubmed.ncbi.nlm.nih.gov/27981915/
Fontan Surgery
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Prepared by Thomas Blount, MD and Steven Matthies (parent)
This study looks at a new technique for the Fontan surgery that uses the patient’s tissue to create the Fontan pathway that may be more likely to grow along with them.
Research Article Used: Marciniak, M. C., Kubba, R., Tran, J. C., Jutzy, G. J., Newcombe, J., Razzouk, A. J., & Fortuna, R. S. (2024). Novel lateral tunnel Fontan operation in children promotes continued pathway growth into adulthood. JTCVS techniques, 29, 138–145. https://doi.org/10.1016/j.xjtc.2024.09.025
Pediatric Fontan
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Prepared By: Jason Williams, MD (physician) and Steven Matthies (parent)
This study follows patients who underwent hybrid versus Norwood surgeries and progressed to Fontan completion, and examines them based on composite outcome.
Research Article Used: Multicenter comparison of hybrid and Norwood procedures in patients with Fontan circulation. Kobayashi et al. The Journal of Thoracic and Cardiovascular Surgery. 2026 May 2. PMID: 42081973
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Physicians: Gabriel Bahrami, Sarah Plummer
Parent: Richard James
The tube (extracardiac conduit or ECC) used to complete the Fontan circuit in the Fontan operation can narrow over time. This study looks at the effects of this narrowing on heart function, exercise tolerance, laboratory tests, and liver fibrosis in Fontan patients.
Research Article Used: Ponzoni M, Saleh J, Chaturvedi RR, Dipchand AI, Valverde I, Seed M, Yoo SJ, Coles J, Honjo O, Lam CZ.J Thorac Cardiovasc Surg. 2025 Oct 3:S0022-5223(25)00855-4. doi: 10.1016/j.jtcvs.2025.09.044. Online ahead of print. PMID: 41047073
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Physician: Dr. Harish Rudra
Parent: Steven Matthies
As survival after the Fontan improves, many patients are living into adulthood; however, these patients can develop long-term serious complications related to the altered circulation associated with the Fontan. The goal of this study was to determine which complications (arrhythmias, liver disease, cyanosis, cardiac dysfunction/heart failure) lead to the primary outcome measures (heart transplant, hepatocellular carcinoma, or death).
Research Article Used:
Patel, N. Risk Factors for Adverse Events in the Fontan Population: Does Ventricular Morphology Play a Role?∗ . JACC Adv. 2024 Apr, 3 (4) .https://doi.org/10.1016/j.jacadv.2024.100870
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Colleen Coffey (parent) and Dr. Harish Rudra (physician)
This study evaluated prevalence and development of liver cirrhosis between the 2 different types of Fontan operations (Lateral Tunnel versus Extracardiac Conduit)
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Richard James (Parent) and Jason Williams, MD (Physician)
This study examines health outcomes of children with single ventricle conditions (HLHS or other single right ventricle anomaly) in the Single Ventricle Reconstruction III Trial (SVR III) up to the age of 12. The goal of this study was to see if the type of shunt makes a difference in health outcomes of children with single ventricle heart conditions.
Research Article Used: Goldberg CS, Trachtenberg F, William Gaynor J, Mahle WT, Ravishankar C, Schwartz SM, Cnota JF, Ohye RG, Gongwer R, Taylor M, Paridon S, Frommelt PC, Afton K, Atz AM, Burns KM, Detterich JA, Hill KD, Cabrera AG, Lewis AB, Pizarro C, Shah A, Sharma B, Newburger JW; Pediatric Heart Network Investigators. Longitudinal Follow-Up of Children With HLHS and Association Between Norwood Shunt Type and Long-Term Outcomes: The SVR III Study. Circulation. 2023 Oct 24;148(17):1330-1339. doi: 10.1161/CIRCULATIONAHA.123.065192. Epub 2023 Oct 5. PMID: 37795623; PMCID: PMC10589429.
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Thomas Zellers MD (physician) and Steven Matthies (parent)
The study summarized shows that neither the type of shunt nor the type of Fontan is associated with life threatening arrhythmias in young patients (out to 6 years post procedure).
Research Article Used:
Cain N, Saul JP, Gongwer R, Trachtenberg F, Czosek RJ, Kim JJ, et al. Relation of Norwood Shunt Type and Frequency of Arrhythmias at 6 Years (from the Single Ventricle Reconstruction Trial). The American Journal of Cardiology. 2022 Jan.
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Katie O’Neill DNP (Nurse Practitioner), Sarah Plummer MD (physician), and Benjamin Nicholas (parent)
The goal of this study is to research how families’ function, quality of life, and well-being are affected by their child’s hypoplastic left heart syndrome diagnosis and treatment.
Research Article Used:
Mussatto KA, Van Rompay MI, Trachtenberg FL, Pemberton V, Young-Borkowski L, Uzark K, et al. Family Function, Quality of Life, and Well-Being in Parents of Infants with Hypoplastic Left Heart Syndrome. Journal of Family Nursing. 2021 Feb 4;27(3):222–34.
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Monique Radman MD, MAS (physician) and Judy Walsh (parent)
Since its first description over 40 years ago, the Fontan surgery has become a commonly performed palliative surgery for patients with single ventricle congenital heart disease. As survival improves, we must find ways to improve long-term outcomes and optimize quality of life in this vulnerable patient population.
Research Article Used:
Cordina RL, O’Meagher S, Karmali A, Rae CL, Liess C, Kemp GJ, et al. Resistance training improves cardiac output, exercise capacity and tolerance to positive airway pressure in Fontan physiology. International Journal of Cardiology [Internet]. 2013 Sep 30;168(2):780–8. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0167527312013861
Adult Fontan
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Prepared by:
Physician: Christopher Curzon, DO
Parent: Steven Matthies
The goal of this study is to evaluate whether the size (diameter) of the Fontan pathway affects how well adults with a Fontan circulation can exercise, and whether pathway size plays a role in liver disease seen in these patients.
This study is important because it directly measured blood flow and pressures inside the heart during exercise via catheterization in adult Fontan patients and compared those measurements to the size of their Fontan pathway.
Research Article Used: Jacob Y. Cao, Alexander C. Egbe, C. Charles Jain, Christopher Francois, Patrick S. Kamath, Yves D'Udekem, David Celermajer, Rachael Cordina, William R. Miranda. Fontan pathway diameter in adults undergoing exercise catheterization: Association with hemodynamics, exercise capacity, and liver scores, The Journal of Thoracic and Cardiovascular Surgery, 2026 ,ISSN 0022-5223, https://doi.org/10.1016/j.jtcvs.2026.02.027.
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Prepared by:
Physician: Sasha Opotowsky, MD
Parent: Richard James
The Fontan Outcomes Network (FON) is a partnership between patients, families, and medical professionals from over 30 heart centers in the U.S. and Canada. The goal is to track health information over time and improve care for people living with Fontan circulation through quality improvement and research.
This report shares early findings from the first 1,121 participants enrolled in FON. This report shares early findings from the first 1,121 participants enrolled in FON. Since this study was conducted, FON has partnered with NPC-QIC to merge into a single learning health network, known as the Single Ventricle Outcomes Network (SV-ONE).
Research Article Used: Glenn, T. M., Kasparian, N. A., Amdani, S., Renaud, D., DiMaria, M. V., Teh, J., Leone, D. M., Mahendran, A. K., Pike, N. A., Dolgner, S. J., Cheng, A. L., Rathod, R. H., Vaikunth, S. S., Veeram Reddy, S. R., Vanam, R., Theobald, J., Schumacher, K. R., Hummel, S. A., Conway, J., Goldberg, D. J., … SV-ONE Investigators (2026). The Fontan Outcomes Network: Findings After 2 Years and 1121 Participants. Circulation, 10.1161/CIRCULATIONAHA.125.078152. Advance online publication. https://doi.org/10.1161/CIRCULATIONAHA.125.078152
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Matthew Moehlmann, DO (physician) and Steven Matthies (parent)
Adults who had Fontan surgery (a complex heart operation for single-ventricle heart defects) are at higher risk of death or needing heart transplant. This study created an easy-to-use scoring system to help identify high-risk patients during their first adult cardiology visit.
Research Article Used: Montanaro C, Arvanitaki A, Kerrigan W, Kadani Z, Barracano R, Scognamiglio G, Kempny A, Li W, Brida M, McDonnell E, Habibi H, Dimopoulos K, Rafiq I, Ee Ling H, Alam H, Sarubbi B, Diller GP, Gatzoulis MA. The Fontan Adult Brompton clinical score and mortality risk. Eur Heart J. 2025 May 21;46(20):1933-1945. doi: 10.1093/eurheartj/ehaf137. PMID: 40131022.
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Steven Matthies (Parent) and Christopher Curzon (Physician)
This study looks at the association and outcomes for patients with Fontan circulation diagnosed with hepatocellular carcinoma.
Research Article Used:
Rosenthal, B. E., Hoteit, M. A., Lluri, G., Haeffele, C., Daugherty, T., Krasuski, R. A., Serfas, J. D., de Freitas, R. A., Porlier, A., Lubert, A. M., Wu, F. M., Valente, A. M., Krieger, E. V., Buber, Y., Rodriguez, F. H., 3rd, Gaignard, S., Saraf, A., Hindes, M., Earing, M. G., Lewis, M. J., … Kim, Y. Y. (2025). Characteristics and Survival Outcomes of Hepatocellular Carcinoma After the Fontan Operation. JACC. Advances, 4(4), 101646. Advance online publication. https://doi.org/10.1016/j.jacadv.2025.101646
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Gabriel Bahrami (physician), Sarah Plummer (physician), Steven Matthies (parent)
This study looks at the safety and benefits of a new class of drugs (sodium glucose cotransporter-2 inhibitors or flozins) used for treating heart failure in adults with Fontan circulation
Research Article Used: Skorek, P., Frączek-Jucha, M. M., Sarnecka, A., Skubera, M., Libiszewska, N., & Tomkiewicz-Pająk, L. (2025). Experience with sodium glucose cotransporter-2 inhibitors in adult patients with Fontan circulation. Advances in clinical and experimental medicine : official organ Wroclaw Medical University, 10.17219/acem/194617. Advance online publication. https://doi.org/10.17219/acem/194617
Neurodevelopment
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Prepared by: Harish Rudra, DO (physician) and Richard James (parent)
This study evaluated the correlation between MRI measures of functional brain assessment in different regions of the brain with clinical scores of cognitive function and emotion/behavioral health. This study compared results between children with single ventricle heart disease and children with typical hearts.
Research Article Used: Singh, K. R., Pike, N. A., Kosoyan, D. E., Karunamuni, D. R., Halnon, N. J., Lewis, A. B., & Kumar, R. (2026). Neural Changes in Adolescents with Single Ventricle Congenital Heart Disease. Pediatric cardiology, 10.1007/s00246-025-04141-8. Advance online publication. https://doi.org/10.1007/s00246-025-04141-8
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Prepared by: Jason Williams (physician), Colleen Coffey (parent), and Steven Matthies (parent)
This study evaluated neurodevelopmental outcomes in patients who underwent the Fontan procedure to help determine risk factors for abnormal neurodevelopment.
Research article used: Jessen, C., Rinne, K., Voges, I., Twelkemeyer, I., Schulze-Nagel, J., Scheewe, J., Attmann, T., Uebing, A., & Hansen, J. H. (2025). Childhood Neurocognitive Outcomes in Patients With Fontan Circulation. Journal of the American Heart Association, 14(22), e043769. https://doi.org/10.1161/JAHA.125.043769
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Thomas Blount, MD (physician) and Richard James (parent)
A series of studies called the Single Ventricle Reconstruction (SVR) Trials looked at neurodevelopmental outcomes for patients who were given two of the most common single ventricle surgeries just after birth (the modified Blalock-Taussig-Thomas (mBTT) shunt or the right ventricle to pulmonary artery shunt (RV-PA conduit/Sano shunt)).
Research Article Used: Miller TA, Sharma B, Gongwer R, Trachtenberg FL, Newburger JW, Goldberg CS, Gustafson KE, Gaynor JW, Votava-Smith JK, Lambert LM, Sananes R, Kral MC, Tsang R, Heinrich KP, Cnota J, Shah A, Ilardi D; Pediatric Heart Network Investigators. Neurodevelopmental Outcomes in Early Adolescence: The Pediatric Heart Network Single Ventricle Reconstruction Trial. Circulation. 2025 Jul 17:10.1161/CIRCULATIONAHA.125.074523. doi: 10.1161/CIRCULATIONAHA.125.074523. Epub ahead of print. PMID: 40671650; PMCID: PMC12321229.
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Prepared by: Courtney Thomas, MD and Steven Matthies
This study evaluated early neurodevelopmental outcomes in patients with hypoplastic left heart syndrome who underwent a hybrid stage I palliation compared to those who underwent a Norwood stage I palliation.
Article Used:
Thomas C, Uzark K, Yu S, Zampi JD, Trucco SM, Sood E, Goldberg C. Early Neurodevelopmental Outcomes in Patients Who Undergo Hybrid Stage I Palliation Compared to Norwood Stage I Palliation for Hypoplastic Left Heart Syndrome. Pediatr Cardiol. 2025 Jun 6. doi: 10.1007/s00246-025-03911-8. Epub ahead of print. PMID: 40478296.
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Sinai C. Zyblewski MD (physician) and Richard James (parent)
This study of young children (6 or younger) with single ventricle defects like HLHS describes patterns in how neurodevelopmental deficits are diagnosed during a child’s first years of childhood and how common they are in children with these heart conditions. This study also determines if testing for these deficits at a young age can predict learning, emotional, and behavioral difficulties later in childhood.
Research Article Used:
Sananes R, Goldberg CS, Newburger JW, Hu C, Trachtenberg F, Gaynor JW, et al. Six-Year Neurodevelopmental Outcomes for Children With Single-Ventricle Physiology. Pediatrics [Internet]. 2021 Feb 1;147(2):e2020014589. Available from: https://pubmed.ncbi.nlm.nih.gov/33441486/
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Congenital heart disease (CHD) has been associated with long term neurocognitive changes; prior studies have shown that children with CHD have a higher chance of being in special education. This study looks at children born with a CHD over a 9 year period, which is 3 more birth years than was previously studied.
Research Article Used:
Mulkey SB, Bai S, Luo C, Cleavenger JE, Gibson N, Holland G, et al. School-Age Test Proficiency and Special Education After Congenital Heart Disease Surgery in Infancy. The Journal of Pediatrics [Internet]. 2016 Nov 1;178:47-54.e1. Available from: https://pubmed.ncbi.nlm.nih.gov/27453376/
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This is a very important study because this is a very large group of patients with this heart defect (more than 200) from many different medical centers about whom we have a lot of very good baseline information from the initial Single Ventricle Reconstruction Trial (SVR-I) done when these patients were infants.
Research Article Used:
Goldberg CS, Lu M, Sleeper LA, Mahle WT, Gaynor JW, Williams IA, et al. Factors associated with neurodevelopment for children with single ventricle lesions. The Journal of Pediatrics [Internet]. 2014 Sep 1;165(3):490-496.e8. Available from: https://pubmed.ncbi.nlm.nih.gov/24952712/
Basic/Translational
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Physician: Christopher Curzon, DO Parent: Steven Matthies
This study looks at whether injecting a child’s own umbilical cord blood cells into the heart during surgery could help children with hypoplastic left heart syndrome (HLHS).
Research Article Used
Gallego-Navarro, C., Jaggers, J., Burkhart, H.M. et al. Autologous umbilical cord blood mononuclear cell therapy for hypoplastic left heart syndrome: a nonrandomized control trial of the efficacy and safety of intramyocardial injections. Stem Cell Res Ther16, 215 (2025). https://doi.org/10.1186/s13287-025-04316-3
Other
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Harish Rudro MD (physician) and Steven Matthies (parent)
There have been prior studies evaluating resource use in functional single ventricle patients, but this has been limited to pre-Fontan patients. The main purpose of this study was to assess health care resource utilization from birth until 18 years of age in patients with single ventricle heart conditions.
Research Article Used:
Dorobantu DM, Huang Q, Espuny Pujol F, Brown KL, Franklin RC, Pufulete M, et al. Hospital resource utilization in a national cohort of functionally single ventricle patients undergoing surgical treatment. JTCVS Open [Internet]. 2023 Jun 1; 14:441–61.
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Raj Sahulee (physician) and Steven Matthies (parent)
This study is important because the effects of congenital anomalies of their airway or lung (CAAL) may negatively impact outcomes for those with Hypoplastic Left Heart Syndrome (HLHS), but little is known at this time.
Research Article Used:
Sahulee R, Singh RK, Pasternack DM. The Prevalence of Congenital Anomalies of the Airway or Lung in Infants with Hypoplastic Left Heart Syndrome and Differences in Midterm Outcomes: A National Pediatric Cardiology Quality Improvement Collaborative Registry Analysis. Pediatric Cardiology [Internet]. 2022 Jun 22 [cited 2022 Dec 6]; Available from: https://pubmed.ncbi.nlm.nih.gov/35731252/
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Steven Matthies (Parent) and Matthew Moehlmann, DO (Physician)
The goal of this study was to learn if the presence of one high-risk feature was associated with reduced survival at one year of age compared to those without any high-risk features.
Research Article Used:
Backes ER, Afonso NS, Guffey D, Tweddell JS, Tabbutt S, Rudd NA, O'Harrow G, Molossi S, Hoffman GM, Hill G, Heinle JS, Bhat P, Anderson JB, Ghanayem NS. Cumulative comorbid conditions influence mortality risk after staged palliation for hypoplastic left heart syndrome and variants. J Thorac Cardiovasc Surg. 2023 Jan;165(1):287-298.e4. doi: 10.1016/j.jtcvs.2022.01.056. Epub 2022 Apr 2. PMID: 35599210.
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Tarek Alsaied MD, Tom Glenn MD (physicians) and Stacey Lihn (parent)
This manuscript describes the systematic design of the Fontan Outcomes Network, including the initial steps in development of the lifespan registry and pilot testing of the feasibility of data collection at ten Children’s hospitals.
Research Article Used:
Alsaied T, Allen KY, Anderson JB, Anixt JS, Brown DW, Cetta F, et al. The Fontan outcomes network: first steps towards building a lifespan registry for individuals with Fontan circulation in the United States. Cardiology in the Young [Internet]. 2020 Aug 1;30(8):1070–5. Available from: https://pubmed.ncbi.nlm.nih.gov/32635947/
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Clifford Cua MD (physician), Richard James (parent), Thomas M Zellers MD (physician), Dawn Mazzanti (parent), Tavenner Dibert MD (physician), Jennifer Co-Vu MD (physician), Sarah Plummer MD (physician), Colleen Melchiorre (parent), Ryan Boggs MD (physician), Nicole Fenix (parent)
Since the emergence of the novel coronavirus, SARS-CoV-2, which causes COVID-19 in late 2019, there has been worldwide spread that WHO has now declared it to be a pandemic. It is in this light that the Research Explained Committee has worked to find research articles with the most valuable information on COVID-19 to date (there may be more since the release of this report) and produce Research Explained summary pieces for the community.
Research Articles Used:
Dong Y, Mo X, Hu Y, Qi X, Jiang F, Jiang Z, et al. Epidemiological Characteristics of 2143 Pediatric Patients With 2019 Coronavirus Disease in China. Pediatrics. 2020 Mar 16;145(6):e20200702.
Cruz AT, Zeichner SL. COVID-19 in Children: Initial Characterization of the Pediatric Disease. Pediatrics [Internet]. 2020 Apr 1;145(6). Available from: https://pediatrics.aappublications.org/content/early/2020/03/16/peds.2020-0834.1
Lu X, Zhang L, Du H, Zhang J, Li YY, Qu J, et al. SARS-CoV-2 Infection in Children. New England Journal of Medicine. 2020 Mar 18;382(17).
Gautret P, Lagier J-C, Parola P, Hoang V, Meddeb L, Mailhe M, et al. Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open- label non-randomized clinical trial. International Journal of Antimicrobial Agents [Internet]. 2020;56(1). Available from: https://www.mediterranee-infection.com/wp-content/uploads/2020/03/Hydroxychloroquine_final_DOI_IJAA.pdf
Chen H, Guo J, Wang C, Luo F, Yu X, Zhang W, et al. Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: a retrospective review of medical records. The Lancet [Internet]. 2020 Mar 7;395(10226):809–15. Available from: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30360-3/fulltext
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Nicole Sutton MD (physician) and Richard James (parent)
The NPC-QIC was set up as a “learning network”, which is a collaborative clinical learning community where clinicians could share data and test new treatments with more patients; this was the first time the design had been used in Pediatric cardiology. This article describes the results of the collaborative to improve outcomes.
Research Article Used:
Anderson JB, Brown DW, Lihn S, Mangeot C, Bates KE, Van Bergen AH, et al. Power of a Learning Network in Congenital Heart Disease. World Journal for Pediatric & Congenital Heart Surgery [Internet]. 2019 Jan 1;10(1):66–71. Available from: https://pubmed.ncbi.nlm.nih.gov/30799702/
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Randomized controlled trials are the gold standard for evaluating health care interventions, yet are uncommon in children's heart surgery. This study conducted a systematic review of clinical trials in pediatric cardiac surgery to evaluate the scope and quality of the current international literature.
Research Article Used:
Drury NE, Patel AJ, Oswald NK, Chong C-R, Stickley J, Barron DJ, et al. Randomized controlled trials in children’s heart surgery in the 21st century: a systematic review. European Journal of Cardio-Thoracic Surgery. 2017 Nov 23;53(4):724–31.