A 10-Year Single Center Report on Fontan Attrition and Non-Fontan Candidacy

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Adamson, Zachary West, Mohan John, Pranay Nayi, Shriprasad R Deshpande, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7067106/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: As patients progress through single ventricle (SV) palliation, changing hemodynamics and patient conditions can prevent progression to Fontan. We sought to determine the incidence of Fontan completion at our institution and to investigate the reasons for non-Fontan candidacy. Methods: Patients who underwent superior cavopulmonary anastomosis (SCPA) from 2010 to 2020 at a single institution were included. Pre-Fontan testing was reviewed for all patients and primary reason for non-candidacy was determined based on review of the electronic medical records. Results: Of 427 patients included, 396 (93%) underwent Fontan or were referred for Fontan at the time of the study. Reasons for non-Fontan candidacy in the remaining 31 patients included cardiac reasons (n = 26), mainly univentricular dysfunction or atrioventricular valve (AVV) regurgitation, respiratory conditions (n = 3), or miscellaneous reasons (n = 2). The patients who were non-Fontan candidates due to respiratory conditions and miscellaneous reasons are all alive without further palliation at the time of the study. There are 17 patients (17/31; 55%) in the non-candidacy group who had a heart transplant or were listed for transplant at the time of the study. Non-Fontan candidates had a higher incidence of moderate or severe AVV regurgitation prior to SCPA. There were no other significant differences in hemodynamics pre-SCPA between the Fontan and non-Fontan candidates. Discussion: Thirty-one patients (31/427; 7%) were not Fontan candidates at our center. Our results demonstrate that the reasons for non-Fontan candidacy after completion of SCPA are broadly due to hemodynamic and respiratory concerns. Predicting non-Fontan candidacy at the time of SCPA is difficult based on echocardiographic and hemodynamic catheterization data. Single ventricle physiology stages of palliation superior cavopulmonary anastomosis (SCPA) Fontan operation Non-Fontan candidacy Figures Figure 1 Background The Fontan operation completes single ventricle (SV) palliation and has been shown to have excellent perioperative and long-term outcomes 1 , 2 . However, there are a subset of patients who reach superior cavopulmonary anastomosis (SCPA) but do not advance to Fontan. As patients progress through staged palliation, changing hemodynamics and other medical conditions can prevent completion of Fontan. The attrition of patients between SCPA and Fontan, or failure to complete Fontan, has been described in other literature as approximately 8–13% over different centers and eras 3 , 4 , 5 . Risk factors for mortality throughout SV palliation have been described 6 , 7 , 8 , but there has been less literature regarding the risk of non-Fontan candidacy and the pathways of those who cannot complete SV palliation 9 . Patients on the single ventricle pathway are a heterogeneous group with variability in anatomic diagnosis with single left versus right ventricle, differences in additional surgery needed initially in infancy, and even differences in provider practices leading to variable timing of pre-Fontan testing. 10 , 11 , 12 Non-Fontan candidacy can be a source of emotional stress on the patient, family, and providers. Given the uncertainty of Fontan attrition and lack of literature into pathways after non-Fontan candidacy, we sought to describe the incidence of completion at our institution, investigate the reasons for non-Fontan candidacy, and describe pathways after non-candidacy was determined. Methods This is a retrospective single center study including patients who underwent SV palliation between January 1st, 2010 and December 31st, 2020. Our institutional surgical database was queried and patients who completed superior cavopulmonary anastamosis (SCPA) were included for analysis. Clinical data were extracted from the medical records. Typical age of Fontan was defined as ranging from 2 to 4-years-old based on the majority institutional practice. Patients who completed or were referred for Fontan by 4-years-old were included in the Fontan group. Referral for Fontan required all pre-Fontan testing (cardiac catheterization and transthoracic echocardiogram) had been reviewed at the institutional combined Cardiology and Cardiothoracic Surgery conference and were determined to be a candidate for Fontan. Patients who underwent 1.5 or 2 ventricle repair or were lost to follow up between SCPA and typical age of Fontan were excluded from analysis. Those patients with late referral for provider practice preference were also excluded from analysis in effort to compare patients with similar management strategies. Baseline demographics were obtained from the medical record and notes were reviewed to determine main reason for non-Fontan candidacy or reason for delay of pre-Fontan testing. Cardiac catheterization reports were reviewed for hemodynamic data. Echocardiograms were reviewed pre- and post-SCPA and Fontan to obtain degree of atrioventricular valve (AVV) regurgitation and qualitative functional assessment. This study was approved by the Children’s Healthcare of Atlanta Institutional Review Board (IRB #00000210) and informed consent was waived. Statistical Analysis: Statistical analysis was completed in IBM SPSS version 29.0.2.0 (Armonk, NY). Continuous data were analyzed with paired t-test or Mann-Whitney U test and categorical data were analyzed with Pearson chi square test. A p-value of < 0.05 was considered significant. Results A total of 552 patients who reached SCPA between 2010 and 2020 were reviewed. Patients were excluded from analysis if they underwent 1.5 or 2 ventricle repair (n= 21), if they died prior to pre-Fontan testing (n= 43), moved or were lost to follow up (n= 41), or had delayed pre-Fontan testing beyond 4-years-old (n= 20). The total number of eligible and included patients was 427. Three hundred ninety-six (396) out of 427 included patients (93%) underwent Fontan procedure or were referred for Fontan before the age of 4-years-old (Figure 1). The mean age at time of Fontan was 4.5-years-old. Thirty-one (7%) patients were deemed non-Fontan candidates. Baseline demographics and a breakdown of data between Fontan and non-Fontan candidates are reported in Table 1. Ten of the patients who were considered candidates at our center underwent Fontan at another center for preference to follow the surgeon who did the initial palliation or family relocation, but these patients were included in the Fontan cohort given they were all candidates at our center with testing completed at the typical age. Delayed referral (n= 20) was due to practice variation or family preference in all but 3 patients who had medical reasons delaying pre-Fontan testing, those reasons being poor weight gain, multiple infections delaying the pre-Fontan catheterization, and stage with shunt to the left pulmonary artery due to hypoplasia, respectively. The main practice variation was a desire to delay Fontan until decrease in oxygen saturations, in order to delay the non-cardiac complications of Fontan palliation. Additionally, some patients who underwent Kawashima as the SCPA had variability in Fontan timing. Given that pre-Fontan testing was not done in these patients at the typical age, they were excluded from the analysis. Reasons for non-Fontan candidacy are detailed in Figure 1 and divided into cardiac (n= 26), respiratory (n= 3), and other reasons (n= 2). A majority of patients who were not candidates for cardiac reasons had systolic or diastolic ventricular dysfunction as the primary reason for non-candidacy (n = 15), with fewer having AVV regurgitation or stenosis (n= 8), or pulmonary vein stenosis (n= 3) (Figure 1). Those with AVV regurgitation and were deemed non-candidates had either concurrent ventricular dysfunction or prior attempt at surgical repair of the valve and repeat valve intervention was not thought to be beneficial. Respiratory etiologies included pneumonectomy and obstructive sleep apnea. One patient had a right pneumonectomy and left pulmonary vein stenosis prior to SCPA and another had pneumonectomy due to severe unilateral pulmonary vein stenosis after SCPA. The patients with other reasons for non-candidacy included one patient who was tracheostomy dependent, non-ambulatory, and had abnormal right lung vasculature, and another patient who had complete occlusion of the Kawashima after SCPA that was not able to be resolved medically or surgically. No patient was deemed a non-Fontan candidate after SCPA for a genetic syndrome or neurologic issue. The outcomes from each group are detailed in Figure 1. Most patients with cardiac reasons for non-Fontan candidacy went on to transplant (n= 17), but others have had a Fontan at another center (n= 2), died (n= 3), or remain alive with SCPA (n= 4). Those with respiratory and the other reasons for non-Fontan candidacy are alive with SCPA at the time of the study. There were 2 non-Fontan candidates at our center who went on to undergo Fontan at another center. The reasons for non-Fontan candidacy in these 2 patients were AVV regurgitation (although our center had planned to do an AVV repair before the Fontan whereas the other center did both simultaneously) and pulmonary vein stenosis, respectively. Of the patients who were non-Fontan candidates, 17 went on to heart transplant, 2 underwent Fontan at another center, and 9 are alive with SCPA. Only 3 non-Fontan candidates have died, all 3 of whom had a transplant or were listed for transplant at the time of death. The mean age of patients who are alive with SCPA at the time of the study is 11 years old. Pre-SCPA hemodynamic and echocardiographic data are displayed in Table 2, showing that the only significant variable differing between Fontan and non-Fontan candidates pre-SCPA was the degree of AVV regurgitation, with the non-Fontan group having a higher incidence of moderate or severe AVV regurgitation. Otherwise, the hemodynamic data were similar between the two groups. Pre-Fontan hemodynamics and echocardiographic data are displayed in Table 3. The non-Fontan candidates were smaller at the time of pre-Fontan catheterization. They had significantly lower arterial and venous oxygen saturations, higher ventricular end-diastolic pressure, higher mean pulmonary artery pressures, and lower cardiac index. The QpQs and indexed pulmonary vascular resistance (PVR) was not significantly different between the two groups. On echocardiogram, the non-Fontan patients have higher incidence of moderate or greater AVV regurgitation and moderate or greater ventricular dysfunction. There were 43 patients who died prior to pre-Fontan testing, so they were excluded from the analysis regarding reason for non-Fontan candidacy. The causes of death and comorbid conditions at the time of death for this group are shown in Table 4. Nineteen (44%) of the 43 patients died during the same hospital admission as SCPA operation. The median age of death in this group was 8.5 months old. Discussion Fontan attrition, or failure to complete Fontan after SCPA, has been reported to be approximately 8–13% at other institutions in different single-center studies 3 , 4 , 5 . Of the 427 included patients who underwent stage-2 palliation at our institution, 31 patients (7%) were not Fontan candidates. The largest reason for non-Fontan candidacy was cardiac reasons (26/31, 84%) including AVV regurgitation and ventricular dysfunction with a smaller subset of patients having respiratory (3/31, 10%) or other reasons (2/31, 6.5%). The only significant finding on pre-SCPA echocardiogram and cardiac catheterization data was an increased incidence of moderate or severe AVV regurgitation and moderate or severe ventricular dysfunction in the non-Fontan group. As expected, those who were not Fontan candidates did have significant differences in Fontan cardiac catheterization data with increased ventricular end-diastolic pressure, pulmonary artery pressure, and decreased cardiac index. Unfortunately, other than the echocardiographic findings mentioned, there was no significant finding prior to SCPA that could help determine the likelihood of candidacy at pre-Fontan testing. However, despite not being candidates for Fontan, a significant number of patients went on to transplant or have survived with SCPA physiology at the time of the study. Interestingly, although many of the patients who died prior to pre-Fontan testing had systolic or diastolic dysfunction, it was not the majority of patients, further demonstrating the lack of ability to predict non-Fontan candidacy at the time of SCPA. In prior single center studies, absolute attrition rates reported may vary based on the exclusion criteria applied to that study. In a 30-year report by Lawrence et al there is an attrition rate of 8.3% when excluding patients who died prior to hospital discharge after SCPA, were awaiting Fontan and deemed a candidate at their institution at the time of the study, were lost to follow up, or underwent two-ventricle repair 3 . With the inherent variability in mind, our study excluded similar patients to the study published by Lawrence et al. Some literature has shown that there is a considerable increased risk of attrition attributable to medical complexity or need for procedures and additional surgeries between the SCPA and Fontan 13 . Surrogates for complexity in these studies included length of stay at the time of the SCPA, longer cardiopulmonary bypass times at SCPA, and additional surgery needs such as AVV repair at the time of SCPA. A study by Stack et al demonstrated that with combined AVV regurgitation and ventricular dysfunction, there is 20 times higher odds of Fontan attrition 4 . Similarly, we found a significant difference in incidence of AVV regurgitation between the Fontan and non-Fontan groups, both on pre-SCPA and pre-Fontan testing. We did not find other differences between the Fontan and non-Fontan candidate groups from the standpoint of aforementioned surrogates for medical complexity. Cardiac reasons for non-Fontan candidacy in our group included AVV regurgitation, ventricular dysfunction, and pulmonary vein stenosis. Interestingly, there were not hemodynamic factors pre-SCPA that were associated with ultimate non-Fontan candidacy, possibly due to the patients with significant differences not undergoing SCPA and thus being excluded from this analysis. Pulmonary vein stenosis and total anomalous pulmonary venous connections (TAPVC) has historically difficult outcomes in single ventricle patients. A study from Geoffrion, et al investigating single ventricle with TAPVC patients from 1984–2021 showed 54% survival to 10-years-old in the era from 2008–2021, that has not significantly improved from the era from 1993-2007. 14 Another study from Sugano et al showed 5-year survival at 58% and freedom from re-stenosis at 54%, with some patients going on to Fontan completion. 15 Three patients in our cohort were non-Fontan candidates due to pulmonary vein stenosis and one did go on to get a Fontan at another center. This patient population has high risk for failure of single ventricle palliation, but based on the literature each patient must be weighed on a case-by-case basis with the knowledge that re-stenosis of pulmonary veins may lead to non-Fontan candidacy. Although the number of patients with pulmonary vein stenosis is small in our study, the two who did not have Fontan are alive, as is the patient who went to another center for Fontan. In our study, patients deemed non-candidates for respiratory reasons all survived with SCPA at the time of this study with an average age of 11-years-old. There are considerable hemodynamic changes on pulmonary artery hemodynamics that can result from respiratory conditions, which may lead to failed Fontan physiology despite favorable hemodynamics with the SCPA at the time of pre-Fontan testing, but there are not outcomes specifically for patients with preexisting respiratory conditions undergoing Fontan, likely due to small sample sizes. Although there are patients who were deemed non-Fontan candidates at both our center and when presented to other centers for second opinion, some of these patients remain alive with SCPA at the time of the study. This begs the question, would there have been an opportunity to complete Fontan palliation at some point, or would the patient have had worse outcome if proceeding with Fontan with their physiology? Is the option of having SCPA as the last stage of palliation an acceptable alternative and destination? This cannot be known from this type of study but would be an interesting avenue for future research. This study also adds to the literature by demonstrating that non-candidacy for Fontan may lead to other avenues, as there may be many years that a patient can live with their SCPA physiology, giving later opportunity for Fontan completion or transplantation if hemodynamics or medical conditions become more favorable. This is supported by a recent study by Miyake et al following 36 patients with SCPA without progression to Fontan. The 20-year survival was approximately 50% in their group with 40-year survival being approximately 40%. 16 Knowledge of this type of data may help in counseling families and patients who are non-Fontan candidates. Limitations of this study include those limitations common to all retrospective studies. In addition, the exclusion criteria pose a challenge due to variability in exclusion criteria amongst similar studies leading to difficulty comparing the attrition rates. We attempted to exclude similar groups of patients as other studies. Excluding patients deceased prior to Fontan evaluation may be excluding a subset of patients who would have been non-Fontan candidates due to failed SCPA physiology, but the main reason for this was to determine non-candidacy in survivors of SCPA. Additionally, not finding differences in pre-SCPA catheterization data may be due to exclusion of those who did not undergo SCPA or died between SCPA and Fontan testing. Unfortunately, there was not pre-Fontan cardiac catheterization data for every non-Fontan candidate for a variety of reasons including family preference to avoid invasive testing when the patient was unlikely to be a candidate based on echocardiographic findings. Conclusions We describe reasons for non-Fontan candidacy and the outcomes of patients who do not undergo Fontan at our institution with an overall attrition rate of 7%. Those who are non-Fontan candidates have a higher incidence of moderate or severe AVV regurgitation or ventricular dysfunction. Prior to Fontan, cardiac catheterization data demonstrates lower cardiac index, higher mean pulmonary artery pressures, and higher ventricular end-diastolic pressure. Earlier in single ventricle palliation, prior to SCPA, it remains difficult to predict those who will not be candidates for Fontan, but the outcomes of non-Fontan candidates can be considered when counseling patients who are not candidates. Abbreviations SCPA – Superior cavopulmonary anastamosis SV – Single ventricle AVV – atrioventricular valve PVR – pulmonary vascular resistance Declarations Conflict of Interest Disclosures: All authors have no financial relationships to disclose. Author Contribution MA, ZW, PN, and AB collected the data. MA and AB prepared the figures and tables. MEF and MA reviewed echocardiogram data and images. AB, SD, MJ, KM, and PC provided supervision and assisted in conceptualization of the idea of the project. All authors assisted in writing, reviewing, and editing manuscript. References Tweddell JS, Nersesian M, Mussatto KA et al (2009) Fontan palliation in the modern era: factors impacting mortality and morbidity. Ann Thorac Surg 88(4):1291–1299. 10.1016/j.athoracsur.2009.05.076 Rogers LS, Glatz AC, Ravishankar C et al (2012) 18 years of the Fontan operation at a single institution: results from 771 consecutive patients. J Am Coll Cardiol 60(11):1018–1025. 10.1016/j.jacc.2012.05.010 Lawrence KM, Ittenbach RF, Hunt ML et al (2021) Attrition between the superior cavopulmonary connection and the Fontan procedure in hypoplastic left heart syndrome. J Thorac Cardiovasc Surg 162(2):385–393. 10.1016/j.jtcvs.2020.10.053 Stack KO, Schluger C, Roberts AL et al (2023) Impact of Ventricular Dysfunction and Atrioventricular Valve Regurgitation on Pre-Fontan Attrition. Ann Thorac Surg 116(4):778–785. 10.1016/j.athoracsur.2023.05.046 Carlo WF, Carberry KE, Heinle JS et al (2011) Interstage attrition between bidirectional Glenn and Fontan palliation in children with hypoplastic left heart syndrome. J Thorac Cardiovasc Surg 142(3):511–516. 10.1016/j.jtcvs.2011.01.030 Cnota JF, Allen KR, Colan S et al (2013) Superior cavopulmonary anastomosis timing and outcomes in infants with single ventricle. J Thorac Cardiovasc Surg 145(5):1288–1296. 10.1016/j.jtcvs.2012.07.069 Rochelson E, Richmond ME, LaPar DJ, Torres A, Anderson BR (2020) Identification of Risk Factors for Early Fontan Failure. Semin Thorac Cardiovasc Surg 32(3):522–528. 10.1053/j.semtcvs.2020.02.018 Alsaied T, Bokma JP, Engel ME et al (2017) Predicting long-term mortality after Fontan procedures: A risk score based on 6707 patients from 28 studies. Congenit Heart Dis 12(4):393–398. 10.1111/chd.12468 Zheng WC, Lee MGY, d'Udekem Y (2022) Fate of Patients With Single Ventricles Who Do Not Undergo the Fontan Procedure. Ann Thorac Surg 114(1):25–33. https://doi.org/10.1016/j.athoracsur.2021.02.011 Wallace MC, Jaggers J, Li JS et al (2011) Center variation in patient age and weight at Fontan operation and impact on postoperative outcomes. Ann Thorac Surg 91(5):1445–1452. 10.1016/j.athoracsur.2010.11.064 Loomba RS, Frommelt PC, Anderson RH, Flores S, Tweddell JS (2019) Timing of Fontan Completion in Children with Functionally Univentricular Hearts and Isomerism: The Impact of Age, Weight, and Pre-Fontan Arterial Oxygen Saturation. Pediatr Cardiol 40(4):753–761. 10.1007/s00246-019-02060-z Pace Napoleone C, Oppido G, Angeli E, Giardini A, Resciniti E, Gargiulo G (2010) Results of the modified Fontan procedure are not related to age at operation. Eur J Cardiothorac Surg 37(3):645–650. 10.1016/j.ejcts.2009.09.003 Ravishankar C, Gerstenberger E, Sleeper LA et al (2016) Factors affecting Fontan length of stay: Results from the Single Ventricle Reconstruction trial. J Thorac Cardiovasc Surg 151(3):669–675e1. 10.1016/j.jtcvs.2015.09.061 Geoffrion TR, Aronowitz DI, Mangeot C et al (2024) Contemporary outcomes for functional single ventricle with total anomalous pulmonary venous connection. J Thorac Cardiovasc Surg 167(6):2177–2185e1. 10.1016/j.jtcvs.2023.09.046 Sugano M, Murata M, Ide Y et al (2019) Midterm results and risk factors of functional single ventricles with extracardiac total anomalous pulmonary venous connection. Gen Thorac Cardiovasc Surg 67(11):941–948. 10.1007/s11748-019-01141-3 Miyake M, Sakamoto J, Kondo H, Iwakura A, Doi H, Tamura T (2023) Forty-year survival after Glenn procedure without Fontan procedure in patients with single ventricle. Eur J Cardiothorac Surg 63(2):ezac528. 10.1093/ejcts/ezac528 Tables Tables 1 to 4 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Fontancandidatetable1.docx Fontancandidatetable2.docx Fontancandidatetable3.docx Fontancandidatetable4.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Adamson","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFklEQVRIiWNgGAWjYJCCAzCGBJhkbwASBhakaOEB8Q0kiLMOokwiAcHGBnTbzz48+OOPHQM/A/PDGz9z6uTMJZ9f3fCjQIKBv707AZsWszPpBod525IZJBvYjC17tx02tpydU3azB+gwiTNnN2DVciCN4TBjAzODwQEGMwnebQcSN9zOSbvBA9RiIJGLXcv5ZwxAh9Uz2B9g/yb5d1td4oabZ9Ju/sGn5UYawwEetsMMBgw8ZtK825gTN9xgP3Ybry03njEA/XKcR+IwT7G1LNAvBmdy2G7LGEjw4PTL+TTmjz/+VMvxt7dvvPl2W52cwfHjz26++WMDFOnFqgUGeBiYEWwDiAgJgP0BKapHwSgYBaNg+AMA9ahjJ0LWPR8AAAAASUVORK5CYII=","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":true,"prefix":"","firstName":"Marissa","middleName":"E.","lastName":"Adamson","suffix":""},{"id":484232375,"identity":"8b5df59b-16d4-4034-940b-9b3916dedc60","order_by":1,"name":"Zachary West","email":"","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"Zachary","middleName":"","lastName":"West","suffix":""},{"id":484232377,"identity":"24525396-03e8-4fb9-91a3-f77c2bcdeba2","order_by":2,"name":"Mohan John","email":"","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"Mohan","middleName":"","lastName":"John","suffix":""},{"id":484232379,"identity":"1bfcbe75-9f83-4721-a75b-0a54549cd9db","order_by":3,"name":"Pranay Nayi","email":"","orcid":"","institution":"Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"Pranay","middleName":"","lastName":"Nayi","suffix":""},{"id":484232382,"identity":"f77d9e25-f7e3-46d2-aeaf-3db15ddc6a26","order_by":4,"name":"Shriprasad R Deshpande","email":"","orcid":"","institution":"Georgetown University School of Medicine, Children’s National Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shriprasad","middleName":"R","lastName":"Deshpande","suffix":""},{"id":484232383,"identity":"9e87ac00-5b12-40dc-bca1-0fb79b3d3bda","order_by":5,"name":"M. Eric Ferguson","email":"","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"M.","middleName":"Eric","lastName":"Ferguson","suffix":""},{"id":484232384,"identity":"18ae5fe0-b84e-484c-be6c-588c82556408","order_by":6,"name":"Kevin O. Maher","email":"","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"Kevin","middleName":"O.","lastName":"Maher","suffix":""},{"id":484232385,"identity":"4fd55699-c70c-4ad3-ace5-f4b8100a2640","order_by":7,"name":"Paul Chai","email":"","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"Paul","middleName":"","lastName":"Chai","suffix":""},{"id":484232386,"identity":"7f12c0c9-ae4c-4de0-9a15-66bb97ec33ba","order_by":8,"name":"Asaad G. Beshish","email":"","orcid":"","institution":"Emory University School of Medicine, Children’s Healthcare of Atlanta","correspondingAuthor":false,"prefix":"","firstName":"Asaad","middleName":"G.","lastName":"Beshish","suffix":""}],"badges":[],"createdAt":"2025-07-07 15:38:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7067106/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7067106/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87029296,"identity":"41d150d7-08d0-4c17-ba3a-c782df37ffe1","added_by":"auto","created_at":"2025-07-18 12:38:28","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":662426,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version.\u003c/p\u003e","description":"","filename":"NonFontanCandidacyFinalFigure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7067106/v1/1b773eeced84b403d59ae567.jpg"},{"id":90622845,"identity":"8ead8d02-7786-4306-850f-3a2b1e27a7d7","added_by":"auto","created_at":"2025-09-04 21:31:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1098630,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7067106/v1/185633cd-e21c-459f-a5eb-d4aa84733899.pdf"},{"id":87028236,"identity":"8aebcbe8-4c83-4b3c-a36f-c97f6cb763ae","added_by":"auto","created_at":"2025-07-18 12:30:28","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":15933,"visible":true,"origin":"","legend":"","description":"","filename":"Fontancandidatetable1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7067106/v1/8d5cd50b59b9546942359777.docx"},{"id":87029301,"identity":"78dbf6e9-2d57-4c4a-8381-0f304464790f","added_by":"auto","created_at":"2025-07-18 12:38:29","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":20499,"visible":true,"origin":"","legend":"","description":"","filename":"Fontancandidatetable2.docx","url":"https://assets-eu.researchsquare.com/files/rs-7067106/v1/1d19b2bcf990fae963015edb.docx"},{"id":87029298,"identity":"f238ad51-2348-46a5-9fd7-8c66984fe2cc","added_by":"auto","created_at":"2025-07-18 12:38:29","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":19990,"visible":true,"origin":"","legend":"","description":"","filename":"Fontancandidatetable3.docx","url":"https://assets-eu.researchsquare.com/files/rs-7067106/v1/61d500eb8be02d1b24d61bf6.docx"},{"id":87028241,"identity":"6eb40698-534d-43a0-bb6e-13119b4cb4a2","added_by":"auto","created_at":"2025-07-18 12:30:29","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":15424,"visible":true,"origin":"","legend":"","description":"","filename":"Fontancandidatetable4.docx","url":"https://assets-eu.researchsquare.com/files/rs-7067106/v1/08b508518fe354ea7509b07e.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"A 10-Year Single Center Report on Fontan Attrition and Non-Fontan Candidacy","fulltext":[{"header":"Background","content":"\u003cp\u003eThe Fontan operation completes single ventricle (SV) palliation and has been shown to have excellent perioperative and long-term outcomes\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. However, there are a subset of patients who reach superior cavopulmonary anastomosis (SCPA) but do not advance to Fontan. As patients progress through staged palliation, changing hemodynamics and other medical conditions can prevent completion of Fontan. The attrition of patients between SCPA and Fontan, or failure to complete Fontan, has been described in other literature as approximately 8\u0026ndash;13% over different centers and eras\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Risk factors for mortality throughout SV palliation have been described\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e, but there has been less literature regarding the risk of non-Fontan candidacy and the pathways of those who cannot complete SV palliation\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Patients on the single ventricle pathway are a heterogeneous group with variability in anatomic diagnosis with single left versus right ventricle, differences in additional surgery needed initially in infancy, and even differences in provider practices leading to variable timing of pre-Fontan testing.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e Non-Fontan candidacy can be a source of emotional stress on the patient, family, and providers. Given the uncertainty of Fontan attrition and lack of literature into pathways after non-Fontan candidacy, we sought to describe the incidence of completion at our institution, investigate the reasons for non-Fontan candidacy, and describe pathways after non-candidacy was determined.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThis is a retrospective single center study including patients who underwent SV palliation between January 1st, 2010 and December 31st, 2020. Our institutional surgical database was queried and patients who completed superior cavopulmonary anastamosis (SCPA) were included for analysis. Clinical data were extracted from the medical records. Typical age of Fontan was defined as ranging from 2 to 4-years-old based on the majority institutional practice. Patients who completed or were referred for Fontan by 4-years-old were included in the Fontan group. Referral for Fontan required all pre-Fontan testing (cardiac catheterization and transthoracic echocardiogram) had been reviewed at the institutional combined Cardiology and Cardiothoracic Surgery conference and were determined to be a candidate for Fontan. Patients who underwent 1.5 or 2 ventricle repair or were lost to follow up between SCPA and typical age of Fontan were excluded from analysis. Those patients with late referral for provider practice preference were also excluded from analysis in effort to compare patients with similar management strategies. Baseline demographics were obtained from the medical record and notes were reviewed to determine main reason for non-Fontan candidacy or reason for delay of pre-Fontan testing. Cardiac catheterization reports were reviewed for hemodynamic data. Echocardiograms were reviewed pre- and post-SCPA and Fontan to obtain degree of atrioventricular valve (AVV) regurgitation and qualitative functional assessment. This study was approved by the Children\u0026rsquo;s Healthcare of Atlanta Institutional Review Board (IRB #00000210) and informed consent was waived.\u003c/p\u003e\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis:\u003c/h2\u003e\u003cp\u003eStatistical analysis was completed in IBM SPSS version 29.0.2.0 (Armonk, NY). Continuous data were analyzed with paired t-test or Mann-Whitney U test and categorical data were analyzed with Pearson chi square test. A p-value of \u0026lt;\u0026thinsp;0.05 was considered significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 552 patients who reached SCPA between 2010 and 2020 were reviewed. Patients were excluded from analysis if they underwent 1.5 or 2 ventricle repair (n= 21), if they died prior to pre-Fontan testing (n= 43), moved or were lost to follow up (n= 41), or had delayed pre-Fontan testing beyond 4-years-old (n= 20). The total number of eligible and included patients was 427. Three hundred ninety-six (396) out of 427 included patients (93%) underwent Fontan procedure or were referred for Fontan before the age of 4-years-old (Figure 1). The mean age at time of Fontan was 4.5-years-old. Thirty-one (7%) patients were deemed non-Fontan candidates. Baseline demographics and a breakdown of data between Fontan and non-Fontan candidates are reported in Table 1. Ten of the patients who were considered candidates at our center underwent Fontan at another center for preference to follow the surgeon who did the initial palliation or family relocation, but these patients were included in the Fontan cohort given they were all candidates at our center with testing completed at the typical age. Delayed referral (n= 20) was due to practice variation or family preference in all but 3 patients who had medical reasons delaying pre-Fontan testing, those reasons being poor weight gain, multiple infections delaying the pre-Fontan catheterization, and stage with shunt to the left pulmonary artery due to hypoplasia, respectively. The main practice variation was a desire to delay Fontan until decrease in oxygen saturations, in order to delay the non-cardiac complications of Fontan palliation. Additionally, some patients who underwent Kawashima as the SCPA had variability in Fontan timing. Given that pre-Fontan testing was not done in these patients at the typical age, they were excluded from the analysis.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eReasons for non-Fontan candidacy are detailed in Figure 1 and divided into cardiac (n= 26), respiratory (n= 3), and other reasons (n= 2). A majority of patients who were not candidates for cardiac reasons had systolic or diastolic ventricular dysfunction as the primary reason for non-candidacy (n = 15), with fewer having AVV regurgitation or stenosis (n= 8), or pulmonary vein stenosis (n= 3) (Figure 1). Those with AVV regurgitation and were deemed non-candidates had either concurrent ventricular dysfunction or prior attempt at surgical repair of the valve and repeat valve intervention was not thought to be beneficial. Respiratory etiologies included pneumonectomy and obstructive sleep apnea. One patient had a right pneumonectomy and left pulmonary vein stenosis prior to SCPA and another had pneumonectomy due to severe unilateral pulmonary vein stenosis after SCPA. The patients with other reasons for non-candidacy included one patient who was tracheostomy dependent, non-ambulatory, and had abnormal right lung vasculature, and another patient who had complete occlusion of the Kawashima after SCPA that was not able to be resolved medically or surgically. No patient was deemed a non-Fontan candidate after SCPA for a genetic syndrome or neurologic issue. The outcomes from each group are detailed in Figure 1. Most patients with cardiac reasons for non-Fontan candidacy went on to transplant (n= 17), but others have had a Fontan at another center (n= 2), died (n= 3), or remain alive with SCPA (n= 4). Those with respiratory and the other reasons for non-Fontan candidacy are alive with SCPA at the time of the study. There were 2 non-Fontan candidates at our center who went on to undergo Fontan at another center. The reasons for non-Fontan candidacy in these 2 patients were AVV regurgitation (although our center had planned to do an AVV repair before the Fontan whereas the other center did both simultaneously) and pulmonary vein stenosis, respectively. Of the patients who were non-Fontan candidates, 17 went on to heart transplant, 2 underwent Fontan at another center, and 9 are alive with SCPA. Only 3 non-Fontan candidates have died, all 3 of whom had a transplant or were listed for transplant at the time of death. The mean age of patients who are alive with SCPA at the time of the study is 11 years old.\u003c/p\u003e\n\u003cp\u003ePre-SCPA hemodynamic and echocardiographic data are displayed in Table 2, showing that the only significant variable differing between Fontan and non-Fontan candidates pre-SCPA was the degree of AVV regurgitation, with the non-Fontan group having a higher incidence of moderate or severe AVV regurgitation. Otherwise, the hemodynamic data were similar between the two groups.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePre-Fontan hemodynamics and echocardiographic data are displayed in Table 3. The non-Fontan candidates were smaller at the time of pre-Fontan catheterization. They had significantly lower arterial and venous oxygen saturations, higher ventricular end-diastolic pressure, higher mean pulmonary artery pressures, and lower cardiac index. The QpQs and indexed pulmonary vascular resistance (PVR) was not significantly different between the two groups. On echocardiogram, the non-Fontan patients have higher incidence of moderate or greater AVV regurgitation and moderate or greater ventricular dysfunction.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThere were 43 patients who died prior to pre-Fontan testing, so they were excluded from the analysis regarding reason for non-Fontan candidacy. The causes of death and comorbid conditions at the time of death for this group are shown in Table 4. Nineteen (44%) of the 43 patients died during the same hospital admission as SCPA operation. The median age of death in this group was 8.5 months old.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eFontan attrition, or failure to complete Fontan after SCPA, has been reported to be approximately 8\u0026ndash;13% at other institutions in different single-center studies\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Of the 427 included patients who underwent stage-2 palliation at our institution, 31 patients (7%) were not Fontan candidates. The largest reason for non-Fontan candidacy was cardiac reasons (26/31, 84%) including AVV regurgitation and ventricular dysfunction with a smaller subset of patients having respiratory (3/31, 10%) or other reasons (2/31, 6.5%). The only significant finding on pre-SCPA echocardiogram and cardiac catheterization data was an increased incidence of moderate or severe AVV regurgitation and moderate or severe ventricular dysfunction in the non-Fontan group. As expected, those who were not Fontan candidates did have significant differences in Fontan cardiac catheterization data with increased ventricular end-diastolic pressure, pulmonary artery pressure, and decreased cardiac index. Unfortunately, other than the echocardiographic findings mentioned, there was no significant finding prior to SCPA that could help determine the likelihood of candidacy at pre-Fontan testing. However, despite not being candidates for Fontan, a significant number of patients went on to transplant or have survived with SCPA physiology at the time of the study. Interestingly, although many of the patients who died prior to pre-Fontan testing had systolic or diastolic dysfunction, it was not the majority of patients, further demonstrating the lack of ability to predict non-Fontan candidacy at the time of SCPA.\u003c/p\u003e\u003cp\u003eIn prior single center studies, absolute attrition rates reported may vary based on the exclusion criteria applied to that study. In a 30-year report by Lawrence et al there is an attrition rate of 8.3% when excluding patients who died prior to hospital discharge after SCPA, were awaiting Fontan and deemed a candidate at their institution at the time of the study, were lost to follow up, or underwent two-ventricle repair\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. With the inherent variability in mind, our study excluded similar patients to the study published by Lawrence et al. Some literature has shown that there is a considerable increased risk of attrition attributable to medical complexity or need for procedures and additional surgeries between the SCPA and Fontan\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Surrogates for complexity in these studies included length of stay at the time of the SCPA, longer cardiopulmonary bypass times at SCPA, and additional surgery needs such as AVV repair at the time of SCPA. A study by Stack et al demonstrated that with combined AVV regurgitation and ventricular dysfunction, there is 20 times higher odds of Fontan attrition\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Similarly, we found a significant difference in incidence of AVV regurgitation between the Fontan and non-Fontan groups, both on pre-SCPA and pre-Fontan testing. We did not find other differences between the Fontan and non-Fontan candidate groups from the standpoint of aforementioned surrogates for medical complexity.\u003c/p\u003e\u003cp\u003eCardiac reasons for non-Fontan candidacy in our group included AVV regurgitation, ventricular dysfunction, and pulmonary vein stenosis. Interestingly, there were not hemodynamic factors pre-SCPA that were associated with ultimate non-Fontan candidacy, possibly due to the patients with significant differences not undergoing SCPA and thus being excluded from this analysis. Pulmonary vein stenosis and total anomalous pulmonary venous connections (TAPVC) has historically difficult outcomes in single ventricle patients. A study from Geoffrion, et al investigating single ventricle with TAPVC patients from 1984\u0026ndash;2021 showed 54% survival to 10-years-old in the era from 2008\u0026ndash;2021, that has not significantly improved from the era from 1993-2007.\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e Another study from Sugano et al showed 5-year survival at 58% and freedom from re-stenosis at 54%, with some patients going on to Fontan completion.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e Three patients in our cohort were non-Fontan candidates due to pulmonary vein stenosis and one did go on to get a Fontan at another center. This patient population has high risk for failure of single ventricle palliation, but based on the literature each patient must be weighed on a case-by-case basis with the knowledge that re-stenosis of pulmonary veins may lead to non-Fontan candidacy. Although the number of patients with pulmonary vein stenosis is small in our study, the two who did not have Fontan are alive, as is the patient who went to another center for Fontan.\u003c/p\u003e\u003cp\u003eIn our study, patients deemed non-candidates for respiratory reasons all survived with SCPA at the time of this study with an average age of 11-years-old. There are considerable hemodynamic changes on pulmonary artery hemodynamics that can result from respiratory conditions, which may lead to failed Fontan physiology despite favorable hemodynamics with the SCPA at the time of pre-Fontan testing, but there are not outcomes specifically for patients with preexisting respiratory conditions undergoing Fontan, likely due to small sample sizes.\u003c/p\u003e\u003cp\u003eAlthough there are patients who were deemed non-Fontan candidates at both our center and when presented to other centers for second opinion, some of these patients remain alive with SCPA at the time of the study. This begs the question, would there have been an opportunity to complete Fontan palliation at some point, or would the patient have had worse outcome if proceeding with Fontan with their physiology? Is the option of having SCPA as the last stage of palliation an acceptable alternative and destination? This cannot be known from this type of study but would be an interesting avenue for future research. This study also adds to the literature by demonstrating that non-candidacy for Fontan may lead to other avenues, as there may be many years that a patient can live with their SCPA physiology, giving later opportunity for Fontan completion or transplantation if hemodynamics or medical conditions become more favorable. This is supported by a recent study by Miyake et al following 36 patients with SCPA without progression to Fontan. The 20-year survival was approximately 50% in their group with 40-year survival being approximately 40%.\u003csup\u003e16\u003c/sup\u003e Knowledge of this type of data may help in counseling families and patients who are non-Fontan candidates.\u003c/p\u003e\u003cp\u003e\u003cem\u003eLimitations of this study\u003c/em\u003e include those limitations common to all retrospective studies. In addition, the exclusion criteria pose a challenge due to variability in exclusion criteria amongst similar studies leading to difficulty comparing the attrition rates. We attempted to exclude similar groups of patients as other studies. Excluding patients deceased prior to Fontan evaluation may be excluding a subset of patients who would have been non-Fontan candidates due to failed SCPA physiology, but the main reason for this was to determine non-candidacy in survivors of SCPA. Additionally, not finding differences in pre-SCPA catheterization data may be due to exclusion of those who did not undergo SCPA or died between SCPA and Fontan testing. Unfortunately, there was not pre-Fontan cardiac catheterization data for every non-Fontan candidate for a variety of reasons including family preference to avoid invasive testing when the patient was unlikely to be a candidate based on echocardiographic findings.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eWe describe reasons for non-Fontan candidacy and the outcomes of patients who do not undergo Fontan at our institution with an overall attrition rate of 7%. Those who are non-Fontan candidates have a higher incidence of moderate or severe AVV regurgitation or ventricular dysfunction. Prior to Fontan, cardiac catheterization data demonstrates lower cardiac index, higher mean pulmonary artery pressures, and higher ventricular end-diastolic pressure. Earlier in single ventricle palliation, prior to SCPA, it remains difficult to predict those who will not be candidates for Fontan, but the outcomes of non-Fontan candidates can be considered when counseling patients who are not candidates.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003e\u003cstrong\u003eSCPA – Superior cavopulmonary anastamosis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSV – Single ventricle\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAVV – atrioventricular valve\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePVR – pulmonary vascular resistance\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflict of Interest Disclosures:\u003c/h2\u003e\u003cp\u003eAll authors have no financial relationships to disclose.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMA, ZW, PN, and AB collected the data. MA and AB prepared the figures and tables. MEF and MA reviewed echocardiogram data and images. AB, SD, MJ, KM, and PC provided supervision and assisted in conceptualization of the idea of the project. All authors assisted in writing, reviewing, and editing manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eTweddell JS, Nersesian M, Mussatto KA et al (2009) Fontan palliation in the modern era: factors impacting mortality and morbidity. Ann Thorac Surg 88(4):1291\u0026ndash;1299. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.athoracsur.2009.05.076\u003c/span\u003e\u003cspan address=\"10.1016/j.athoracsur.2009.05.076\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRogers LS, Glatz AC, Ravishankar C et al (2012) 18 years of the Fontan operation at a single institution: results from 771 consecutive patients. J Am Coll Cardiol 60(11):1018\u0026ndash;1025. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jacc.2012.05.010\u003c/span\u003e\u003cspan address=\"10.1016/j.jacc.2012.05.010\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLawrence KM, Ittenbach RF, Hunt ML et al (2021) Attrition between the superior cavopulmonary connection and the Fontan procedure in hypoplastic left heart syndrome. J Thorac Cardiovasc Surg 162(2):385\u0026ndash;393. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.jtcvs.2020.10.053\u003c/span\u003e\u003cspan address=\"10.1016/j.jtcvs.2020.10.053\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eStack KO, Schluger C, Roberts AL et al (2023) Impact of Ventricular Dysfunction and Atrioventricular Valve Regurgitation on Pre-Fontan Attrition. 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Ann Thorac Surg 91(5):1445\u0026ndash;1452. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.athoracsur.2010.11.064\u003c/span\u003e\u003cspan address=\"10.1016/j.athoracsur.2010.11.064\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLoomba RS, Frommelt PC, Anderson RH, Flores S, Tweddell JS (2019) Timing of Fontan Completion in Children with Functionally Univentricular Hearts and Isomerism: The Impact of Age, Weight, and Pre-Fontan Arterial Oxygen Saturation. 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Gen Thorac Cardiovasc Surg 67(11):941\u0026ndash;948. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11748-019-01141-3\u003c/span\u003e\u003cspan address=\"10.1007/s11748-019-01141-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMiyake M, Sakamoto J, Kondo H, Iwakura A, Doi H, Tamura T (2023) Forty-year survival after Glenn procedure without Fontan procedure in patients with single ventricle. Eur J Cardiothorac Surg 63(2):ezac528. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ejcts/ezac528\u003c/span\u003e\u003cspan address=\"10.1093/ejcts/ezac528\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 4 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Single ventricle physiology, stages of palliation, superior cavopulmonary anastomosis (SCPA), Fontan operation, Non-Fontan candidacy","lastPublishedDoi":"10.21203/rs.3.rs-7067106/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7067106/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground:\u003c/h2\u003e\u003cp\u003eAs patients progress through single ventricle (SV) palliation, changing hemodynamics and patient conditions can prevent progression to Fontan. We sought to determine the incidence of Fontan completion at our institution and to investigate the reasons for non-Fontan candidacy.\u003c/p\u003e\u003ch2\u003eMethods:\u003c/h2\u003e\u003cp\u003ePatients who underwent superior cavopulmonary anastomosis (SCPA) from 2010 to 2020 at a single institution were included. Pre-Fontan testing was reviewed for all patients and primary reason for non-candidacy was determined based on review of the electronic medical records.\u003c/p\u003e\u003ch2\u003eResults:\u003c/h2\u003e\u003cp\u003eOf 427 patients included, 396 (93%) underwent Fontan or were referred for Fontan at the time of the study. Reasons for non-Fontan candidacy in the remaining 31 patients included cardiac reasons (n\u0026thinsp;=\u0026thinsp;26), mainly univentricular dysfunction or atrioventricular valve (AVV) regurgitation, respiratory conditions (n\u0026thinsp;=\u0026thinsp;3), or miscellaneous reasons (n\u0026thinsp;=\u0026thinsp;2). The patients who were non-Fontan candidates due to respiratory conditions and miscellaneous reasons are all alive without further palliation at the time of the study. There are 17 patients (17/31; 55%) in the non-candidacy group who had a heart transplant or were listed for transplant at the time of the study. Non-Fontan candidates had a higher incidence of moderate or severe AVV regurgitation prior to SCPA. There were no other significant differences in hemodynamics pre-SCPA between the Fontan and non-Fontan candidates.\u003c/p\u003e\u003ch2\u003eDiscussion:\u003c/h2\u003e\u003cp\u003eThirty-one patients (31/427; 7%) were not Fontan candidates at our center. Our results demonstrate that the reasons for non-Fontan candidacy after completion of SCPA are broadly due to hemodynamic and respiratory concerns. Predicting non-Fontan candidacy at the time of SCPA is difficult based on echocardiographic and hemodynamic catheterization data.\u003c/p\u003e","manuscriptTitle":"A 10-Year Single Center Report on Fontan Attrition and Non-Fontan Candidacy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-18 12:30:24","doi":"10.21203/rs.3.rs-7067106/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"90135234-463d-4dd7-9394-19cd4a242989","owner":[],"postedDate":"July 18th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-04T21:23:13+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-18 12:30:24","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7067106","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7067106","identity":"rs-7067106","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}