Influence of Aortic Arch Form on Right Ventricular Function After the Norwood Procedure

Influence of Aortic Arch Form on Right Ventricular Function After the Norwood Procedure | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Influence of Aortic Arch Form on Right Ventricular Function After the Norwood Procedure Tomomitsu Kanaya, Sanae Tsumura, Koji Miwa, Yuta Teguri This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4573212/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 The outcomes of patients with hypoplastic left heart syndrome (HLHS) have significantly improved in recent years due to the utilization of the Norwood procedure. Unobstructed outflow through the aortic arch is important for maintaining right ventricular function. Some reports have shown that an aortic arch with a high-degree tapering form leads to increased energy loss; however, the correlation between right ventricular function and the degree of aortic arch tapering remains unknown. This retrospective, single-center analysis aimed to investigate the impact of aortic arch tapering following the Norwood procedure on circulation dynamics and right ventricular function. During the study period, 14 patients who underwent the Norwood procedure for HLHS and enhanced computed tomography before the Glenn procedure were included. The median age of the patients at the time of the Norwood procedure was 30 days (25–269 days), and the median weight was 3.0 kg (2.6–4.4 kg). As an indicator of the degree of tapering of the aortic arch, we used the standard deviation (SD) of the diameters of the ascending aorta, transverse arch, isthmus, and descending aorta (arch SD). There was a significant negative correlation between the cardiac index and arch SD. Furthermore, there was a significant negative correlation between the right ventricular fractional area change and arch SD. In conclusion, an unobstructed and minimally tapered aortic arch is essential for maintaining optimal right ventricular function. hypoplastic left heart syndrome Norwood procedure arch reconstruction cardiac index Figures Figure 1 Figure 2 INTRODUCTION The outcomes of patients with hypoplastic left heart syndrome (HLHS) have significantly improved in recent years [ 1 , 2 ]. This improvement in survival and morbidity in patients with HLHS is associated with the quality of the Norwood procedure as a palliative surgical procedure [ 3 , 4 ]. In the Norwood procedure, it is important to achieve an unobstructed form of the aortic arch to reduce complications and obtain good long-term circulation. Recurrent coarctation of the distal aortic arch (reCoA) is a major challenge following the Norwood procedure [ 5 , 6 ]. Residual reCoA has also been reported to worsen right ventricular function and tricuspid regurgitation, requiring ingenuity in aortic reconstruction to avoid a high postoperative afterload. The interdigitating technique is a surgical procedure developed to avoid reCoA, and its usefulness has been reported in various studies [ 7 ]. Additionally, chimney reconstruction has been reported to be a useful technique for smooth aortic arch reconstruction without energy loss because it has the effect of horizontal plication to dilate the neo-aortic root [ 8 ]. Several studies have recently reported that energy loss can be influenced by the geometry and tapering of the aortic arch following the Norwood procedure [ 8 , 9 ]. However, the precise impact on circulatory dynamics and right ventricular function remains unclear. This study aimed to investigate the tapering of the aortic arch using computed tomography (CT) following the Norwood procedure and to assess its effect on circulation dynamics and right ventricular function. METHODS Patients This single-center, retrospective cohort study, conducted between January 2014 and December 2022, included 14 patients who underwent the Norwood procedure for HLHS and HLHS variants and enhanced CT before the Glenn procedure. All neo-aortic reconstructions were performed using autologous pericardium treated with 0.5% glutaraldehyde from the posterior wall to the lesser curvature of the arch. From 2018, coarctectomy was performed using an interdigitating technique, as described by Burkhart et al. [ 7 ], and chimney reconstruction was performed as described by Yamagishi and colleagues [ 8 ]. We routinely performed echocardiography, cardiac CT, and cardiac catheterization before the Glenn procedure and Fontan operation. This study was approved by the Ethics Committee of Osaka Women’s and Children’s Hospital. Aortic arch geometry Geometric measurements of the aortic arch were obtained from CT images. The diameters were measured at the level of the neo-aortic ascending aorta (aAo), transverse aortic arch (TA), aortic isthmus (iAo), and mid-descending aorta (dAo), as described previously [ 9 ]. The degree of aortic tapering was defined as the standard deviation (SD) of the diameter values (arch SD) measured at the aforementioned locations. Evaluation of right ventricular function Right ventricular fractional area change (RVFAC) was calculated from the apical imaging planes using echocardiography. Cardiac catheterization was used to evaluate the right ventricular function as a cardiac index (CI) and right ventricular ejection fraction (RVEF). These examinations were performed before the Glenn procedure. Data analysis Continuous variables were presented as medians and ranges, while categorical variables were reported as frequencies. All statistical analyses were performed using JMP Pro 14 software (SAS Inc., Cary, NC, USA), and a P-value < 0.05 was considered statistically significant. The relationships between the arch SD and measures of right ventricular function were evaluated using linear regression analysis. RESULTS Patient outcomes Between January 2014 and December 2021, 14 patients with HLHS who underwent the Norwood procedure and enhanced CT before the Glenn procedure were included. The patient characteristics are shown in Table 1 . Five patients (35.6%) completed Fontan surgery, one patient died due to hepatoblastoma, and the other eight patients were waiting for Fontan surgery. Thirteen patients (92.8%) underwent bilateral pulmonary artery banding as the first palliation. During the Norwood procedure, all patients underwent a right ventricle-to-pulmonary artery (RVPA) shunt. Nine patients (64.2%) had an interdigitating suture, and eight patients (57.1%) underwent the chimney technique for arch reconstruction. The median time from the Norwood procedure to enhanced CT was 4 months (range: 1–20 months). Eight patients (57.1%) subsequently completed the Fontan operation, while the other five (35.7%) were waiting. Figure 1 shows the Fontan completion curve; the rate of Fontan completion was 75% by 5 years of age. Table 1 Patients’ characteristics Characteristics Age at Norwood, median, days 30 (25–269) Body weight at Norwood, kg 3.0 (2.6–4.4) Male, n (%) 7 (50) HLHS subtype, n (%) MA/AA 2 (14.2) MS/AA 2 (14.2) MA/AS 1 (7.1) MS/AS 9 (64.2) Previous operation, n (%) Primary Norwood 1 (7.1) Bilateral PAB 13 (92.8) RV-PA shunt, n (%) 14 (100) Interdigitating suture, n (%) 9 (64.2) Chimney technique, n (%) 8 (57.1) Glenn completion, n (%) 14 (100) Age at Glenn, months 7.6 (5.3–14.4) Body weight at Glenn, kg 5.8 (5.1–7.4) Fontan completion, n (%) 8 (57.1) Age at Fontan, months 26.9 (23.4–31.7) Body weight at Fontan, kg 10.7 (11.0–12.0) Mortality, n (%) 1 (7.1) Hepatoblastoma 1 (7.1) HLHS , hypoplastic left heart syndrome; MA , mitral atresia; AA , aortic atresia; MS , mitral stenosis; AS , aortic stenosis; PAB, pulmonary artery banding; RV-PA shunt , right ventricle to pulmonary artery shunt. The right ventricular function following the Norwood procedure is shown in Table 2 . Echocardiography showed that the median RVFAC was 43% (range: 29–53%). Cardiac catheterization showed that the CI was 3.4 L/min m 2 (range: 2.5–4.9 L/min m 2 ), RVEF was 53.5% (range: 32–77%), and the pressure gradient from the ascending aorta to the descending aorta was 1 mmHg (0–9 mmHg). Table 2 Right ventricular function after Norwood Time from Norwood to Glenn, months 4 (1–20) Echocardiogram RVFAC, % 43 (29–53) Cardiac catheterization Cardiac index, L/min/m 2 3.4 (2.5–4.9) RVEF, % 53.5 (32–77) RVESVI, ml/m 2 60.9 (26.6–98.0) RVEDVI, ml/m 2 128.5 (102.5–168.0) RVESP, mmHg 76.5 (56.0–87.0) RVEDP, mmHg 7.0 (2.0–10.0) PVR, U・m 2 2.4 (1.5–4.5) ΔaAo-dAo, mmHg 1 (0–9) RVFAC, right ventricular fraction area changes; RVEF, right ventricular ejection fraction; RVESVI, right ventricular end-systolic ventricular volume index; RVEDVI, right ventricular end-diastolic volume index; Aortic arch geometry Enhanced CT was used for geometric analysis of the aortic arch. The diameters of the aAo, TA, iAo, and dAo were 10.6 mm (range: 7.4–13.2 mm), 9.4 mm (range: 6.5–12.5 mm), 5.3 mm (range: 3.0–6.5 mm), and 6.5 mm (range: 5.0–10.1 mm), respectively. The corresponding arch SD was 2.0 (1.4–3.4) (Table 3 ). Table 3 Geometric analysis of aortic arch after Norwood Ascending aorta, mm 10.6 (7.4–13.2) Transverse arch, mm 9.4 (6.5–12.5) Aortic isthmus, mm 5.3 (3.0-6.5) Descending aorta, mm 6.5 (5.0-10.1) Coactation index 2.2 (1.9–2.8) Arch SD 2.0 (1.4–3.4) SD , standard deviation Relationship between right ventricular function and arch geometry There was a significant negative correlation between arch SD and CI before the Glenn procedure (r 2 = 0.43, P < 0.05). Similarly, there was a significant negative relationship between arch SD and RVFAC before the Glenn procedure (r 2 = 0.46, P < 0.05). After the Glenn procedure, no significant relationship between arch SD and CI was observed; however, there was a significant negative correlation between arch SD and RVFAC before the Fontan procedure (r 2 = 0.45, P < 0.05) (Fig. 2 ). DISCUSSION We demonstrated that a smooth aortic arch morphology with minimal diameter discrepancies is essential for maintaining cardiac output and contraction before the Glenn procedure in patients with HLHS who underwent the Norwood procedure. Our findings align with previous studies that reported increased afterload due to reCoA as a risk factor for right ventricular dysfunction or tricuspid valve regurgitation [ 7 , 10 – 12 ]. Even mild obstruction can lead to significant clinical issues and increased early mortality rates. Several studies have explored energy dynamics in this context [ 8 , 9 ]. Asada et al. reported that chimney reconstruction technique used during the Norwood procedure could reduce energy loss and maintain optimal blood flow. Similarly, Michal et al. found that a high degree of Norwood neo-aortic tapering was linked to increased energy loss, with energy losses in the high-degree group accounting for 0.7% of ventricular power generation, compared to 0.3% in the low-degree group. They concluded that oversizing of the Norwood neo-aortic reconstruction should be avoided, as it may lead to single-ventricle deterioration. This aligns with our findings that significant tapering in the aortic arch can adversely impact right ventricukar performance, leading to decrease CI and low RVEF. Although the precise impact of energy loss on right ventricular function remains unclear, our results suggest that high tapering, leading to high energy loss at the aortic arch, could impair right ventricular function. We used the chimney technique for neo-aortic reconstruction, facilitating horizontal plication and longitudinal extension of the neo-aortic trunk while preventing compression of the left pulmonary artery. This approach is designed to minimize energy loss. Burkhart et al. also proposed an interdigitating arch reconstruction technique to reduce reCoAe after the Norwood procedure [ 7 ], demonstrating that this technique could reduce afterload on the right ventricle by preventing aortic arch obstruction. In this study, the use of these two aortic reconstruction methods, along with autologous pericardial patching, appeared to contribute to minimal diameter discrepancy in the aortic arch, potentially reducing afterload on the right ventricle and energy loss. We found a significant correlation between diameter discrepancy, right ventricular function, and CI after the Norwood procedure, suggesting that minimizing diameter differences during the Norwood procedure could be crucial for maintaining right ventricular function before the Fontan operation. There were some limitations to this study. This is a single-center, retrospective cohort study with a small sample size. The patients who did not undergo Glenn procedure or died before Glenn procedure were not included. Right ventricular function in patients with HLHS is influenced by several complex factors, including valve function, collateral circularion, and coronary perfusion. The influence of aortic arch geometry on Fontan circulation over the long term should be explored further. Additionally, changes in arch geometry may occur at different stages post-Glenn and post-Fontan, and interventions could also alter the geometry. CONCLUSION During the Norwood procedure, reconstruction of an unobstructed aortic arch without a significant diameter discrepancy appears to be a critical factor for maintaining right ventricular function and CI before the Glenn procedure. Further investigation are needed to understand the impact of aortic arch geometry on long-term Fontan circulation. Declarations Competing interests The authors have no competing interests to declare that are relevant to the content of this article. Author Contribution T.K. and S.T. wrote the main manuscript text and K.M. and Y.T. prepared figures and Tables. All authors reviewed the manuscript. Acknowledgements: None. References Ohye RG, Schranz D, D’Udekem Y (2016) Current Therapy for Hypoplastic Left Heart Syndrome and Related Single Ventricle Lesions. Circulation 134:1265–1279. https://doi.org/10.1161/CIRCULATIONAHA.116.022816 Tweddell JS, Hoffman GM, Fedderly RT, Berger S, Thomas JP Jr, Ghanayem NS, Kessel MW, Litwin SB (1999) Phenoxybenzamine improves systemic oxygen delivery after the Norwood procedure. Ann Thorac Surg 67:161–167. https://doi.org/10.1016/s0003-4975(98)01266-1 Tanem J, Rudd N, Rauscher J, Scott A, Frommelt MA, Hill GD (2020) Survival After Norwood Procedure in High-Risk Patients. Ann Thorac Surg 109:828–834. https://doi.org/10.1016/j.athoracsur.2019.07.070 Friedland-Little JM, Aiyagari R, Yu S, Donohue JE, Hirsch-Romano JC (2014) Survival Through Staged Palliation: Fate of Infants Supported by Extracorporeal Membrane Oxygenation After the Norwood Operation. Ann Thorac Surg 97:659–665. https://doi.org/10.1016/j.athoracsur.2013.10.066 Bartram U, Grunenfelder J, Van Praagh R (1997) Causes of death after the modified Norwood procedure: a study of 122 postmortem cases. Ann Thorac Surg 64:1795–1802. https://doi.org/10.1016/s0003-4975(97)01041-2 Weinberg PM, Chin AJ, Murphy JD, Pigott JD, Norwood WI (1986) Post-mortem echocardiography and tomographic anatomy of hypoplastic left heart syndrome after palliative surgery. Am J Cardiol 58:1228–1232. https://doi.org/10.1016/0002-9149(86)90387-5 Burkhart HM, Ashburn DA, Konstantinov IE, De Oliviera NC, Benson L, Williams WG, Van Arsdell GS (2005) Interdigitating arch reconstruction eliminates recurrent coarctation after the Norwood procedure. J Thorac Cardiovasc Surg 130:61–65. https://doi.org/10.1016/j.jtcvs.2005.02.060 Asada S, Yamagishi M, Itatani K, Yaku H (2017) Chimney reconstruction of the aortic arch in the Norwood procedure. J Thorac Cardiovasc Surg. 154;e51-e54. https://doi.org/10.1053/j.optechstcvs.2019.10.004 Schafer M, Di Maria MV, Jaggers J, Stone ML, Ivy DD, Barker AJ, Mitchell MB (2021) High-degree Norwood neoaortic tapering is associated with abnormal flow conduction and elevated flow-mediated energy loss. J Thorac Cardiovasc Surg 162:1791–1804. https://doi.org/10.1016/j.jtcvs.2021.01.111 Kobayashi Y, Kotani Y, Kuroko Y, Kawabata T, Sano S, Kasahara S (2020) Norwood procedure with right ventricle to pulmonary artery conduit: a single-centre 20-year experience. Eur J Cardiothorac Surg 58:230–236. https://doi.org/10.1093/ejcts/ezaa041 Alsoufi B, Sinha R, McCracken C, Figueroa J, Altin F, Kanter K (2018) Outcomes and risk factors associated with tricuspid valve repair in children with hypoplastic left heart syndrome. Eur J Cardiothorac Surg 54:993–1000. https://doi.org/10.1093/ejcts/ezy198 Larrazabal LA, Tierney ESS, Brown DW, Gauvreau K, Vida VL, Bergersen L, Pigula FA, del Nido PJ, Bacha EA (2008) Ventricular Function Deteriorates with recurrent coarctation in hypoplastic left heart syndrome. Ann Thorac Surg 86:869–874. https://doi.org/10.1016/j.athoracsur.2008.04.074 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4573212","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":317957715,"identity":"327cf79f-c730-4ea9-a720-b20e96cd232d","order_by":0,"name":"Tomomitsu Kanaya","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+klEQVRIiWNgGAWjYBACCQhlI8fPwMAGYiVABHgIakkzlmwgUcvhxA0HULTgAZLtZw9+5qlJY9x8I/nZA4aKO3n8DMwPHzDI3MGpRZonL1ma55gNs9mNNHMDhjPPiiUb2IwNGHie4dQix5BjIM3DlsZmdjuHTYKxDeRCHjYJBp7DuLXwvzH+zfPvMI/xbGK1SEvkmEnzth2WMJAmVovkjDdmlnP70gwk7j8zk0g48yxxZjPQLwl4/CJxPsf4xptvNvX9PYefSXyouJPYz9788MHHHtwhBgJM8HhLYDjAwMAMZCT2HMCrhfEHgg1T+QO/llEwCkbBKBhRAACsiVNAKc8qiQAAAABJRU5ErkJggg==","orcid":"","institution":"Osaka Women’s and Children’s Hospital","correspondingAuthor":true,"prefix":"","firstName":"Tomomitsu","middleName":"","lastName":"Kanaya","suffix":""},{"id":317957716,"identity":"48fe516f-c577-4a61-996c-0249701433c5","order_by":1,"name":"Sanae Tsumura","email":"","orcid":"","institution":"Osaka Women’s and Children’s Hospital","correspondingAuthor":false,"prefix":"","firstName":"Sanae","middleName":"","lastName":"Tsumura","suffix":""},{"id":317957717,"identity":"550db4ae-9d1c-45b7-b0b3-845930eb11e2","order_by":2,"name":"Koji Miwa","email":"","orcid":"","institution":"Osaka Women’s and Children’s Hospital","correspondingAuthor":false,"prefix":"","firstName":"Koji","middleName":"","lastName":"Miwa","suffix":""},{"id":317957718,"identity":"cee75a16-6f24-4f57-8638-1a93a8d48a21","order_by":3,"name":"Yuta Teguri","email":"","orcid":"","institution":"Osaka Women’s and Children’s Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuta","middleName":"","lastName":"Teguri","suffix":""}],"badges":[],"createdAt":"2024-06-13 03:16:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4573212/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4573212/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":60183920,"identity":"1d8a01f8-b024-4943-a1a4-9e992f22ab89","added_by":"auto","created_at":"2024-07-12 18:34:40","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":20515,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFontan completion curve\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe rate of Fontan completion was 75% at 5 years of age.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4573212/v1/a548085dd99499903ed19b88.jpg"},{"id":60183921,"identity":"37abb20f-3142-44c1-8d39-6ace6dfedf58","added_by":"auto","created_at":"2024-07-12 18:34:40","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":168440,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eComparison between ventricular function and geometry of the aortic arch\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ea) The association between the cardiac index (CI) and each aortic arch geometry is shown. The arch SD and CI are significantly negatively correlated.\u003c/p\u003e\n\u003cp\u003eb) The association between the right ventricle fractional area change (RVFAC) and each aortic geometry is shown. The arch SD and RVFAC have a significant negative correlation.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4573212/v1/08f79e757d92344b0dd62f5d.png"},{"id":60185487,"identity":"ef68ff9b-1ed6-456f-bbc4-c3914b32c100","added_by":"auto","created_at":"2024-07-12 18:42:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":555399,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4573212/v1/39014dfc-f122-4a46-b2e9-ba17c873843a.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Influence of Aortic Arch Form on Right Ventricular Function After the Norwood Procedure","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe outcomes of patients with hypoplastic left heart syndrome (HLHS) have significantly improved in recent years [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. This improvement in survival and morbidity in patients with HLHS is associated with the quality of the Norwood procedure as a palliative surgical procedure [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In the Norwood procedure, it is important to achieve an unobstructed form of the aortic arch to reduce complications and obtain good long-term circulation. Recurrent coarctation of the distal aortic arch (reCoA) is a major challenge following the Norwood procedure [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Residual reCoA has also been reported to worsen right ventricular function and tricuspid regurgitation, requiring ingenuity in aortic reconstruction to avoid a high postoperative afterload. The interdigitating technique is a surgical procedure developed to avoid reCoA, and its usefulness has been reported in various studies [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Additionally, chimney reconstruction has been reported to be a useful technique for smooth aortic arch reconstruction without energy loss because it has the effect of horizontal plication to dilate the neo-aortic root [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Several studies have recently reported that energy loss can be influenced by the geometry and tapering of the aortic arch following the Norwood procedure [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. However, the precise impact on circulatory dynamics and right ventricular function remains unclear.\u003c/p\u003e \u003cp\u003eThis study aimed to investigate the tapering of the aortic arch using computed tomography (CT) following the Norwood procedure and to assess its effect on circulation dynamics and right ventricular function.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003eThis single-center, retrospective cohort study, conducted between January 2014 and December 2022, included 14 patients who underwent the Norwood procedure for HLHS and HLHS variants and enhanced CT before the Glenn procedure. All neo-aortic reconstructions were performed using autologous pericardium treated with 0.5% glutaraldehyde from the posterior wall to the lesser curvature of the arch. From 2018, coarctectomy was performed using an interdigitating technique, as described by Burkhart et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], and chimney reconstruction was performed as described by Yamagishi and colleagues [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. We routinely performed echocardiography, cardiac CT, and cardiac catheterization before the Glenn procedure and Fontan operation. This study was approved by the Ethics Committee of Osaka Women\u0026rsquo;s and Children\u0026rsquo;s Hospital.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAortic arch geometry\u003c/h3\u003e\n\u003cp\u003eGeometric measurements of the aortic arch were obtained from CT images. The diameters were measured at the level of the neo-aortic ascending aorta (aAo), transverse aortic arch (TA), aortic isthmus (iAo), and mid-descending aorta (dAo), as described previously [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The degree of aortic tapering was defined as the standard deviation (SD) of the diameter values (arch SD) measured at the aforementioned locations.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eEvaluation of right ventricular function\u003c/h2\u003e \u003cp\u003eRight ventricular fractional area change (RVFAC) was calculated from the apical imaging planes using echocardiography. Cardiac catheterization was used to evaluate the right ventricular function as a cardiac index (CI) and right ventricular ejection fraction (RVEF). These examinations were performed before the Glenn procedure.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eContinuous variables were presented as medians and ranges, while categorical variables were reported as frequencies. All statistical analyses were performed using JMP Pro 14 software (SAS Inc., Cary, NC, USA), and a P-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant. The relationships between the arch SD and measures of right ventricular function were evaluated using linear regression analysis.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003ePatient outcomes\u003c/h2\u003e\n \u003cp\u003eBetween January 2014 and December 2021, 14 patients with HLHS who underwent the Norwood procedure and enhanced CT before the Glenn procedure were included. The patient characteristics are shown in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e. Five patients (35.6%) completed Fontan surgery, one patient died due to hepatoblastoma, and the other eight patients were waiting for Fontan surgery. Thirteen patients (92.8%) underwent bilateral pulmonary artery banding as the first palliation. During the Norwood procedure, all patients underwent a right ventricle-to-pulmonary artery (RVPA) shunt. Nine patients (64.2%) had an interdigitating suture, and eight patients (57.1%) underwent the chimney technique for arch reconstruction. The median time from the Norwood procedure to enhanced CT was 4 months (range: 1\u0026ndash;20 months). Eight patients (57.1%) subsequently completed the Fontan operation, while the other five (35.7%) were waiting. Figure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e shows the Fontan completion curve; the rate of Fontan completion was 75% by 5 years of age.\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003ePatients\u0026rsquo; characteristics\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge at Norwood, median, \u003cem\u003edays\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30 (25\u0026ndash;269)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBody weight at Norwood, \u003cem\u003ekg\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.0 (2.6\u0026ndash;4.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMale, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7 (50)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHLHS subtype, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMA/AA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (14.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMS/AA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (14.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMA/AS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMS/AS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (64.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePrevious operation, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePrimary Norwood\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBilateral PAB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13 (92.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRV-PA shunt, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eInterdigitating suture, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (64.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eChimney technique, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (57.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eGlenn completion, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge at Glenn, \u003cem\u003emonths\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.6 (5.3\u0026ndash;14.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBody weight at Glenn, \u003cem\u003ekg\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5.8 (5.1\u0026ndash;7.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFontan completion, \u003cem\u003en (%)\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8 (57.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge at Fontan, \u003cem\u003emonths\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26.9 (23.4\u0026ndash;31.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBody weight at Fontan, \u003cem\u003ekg\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.7 (11.0\u0026ndash;12.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMortality, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHepatoblastoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (7.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\"\u003e\u003cem\u003eHLHS\u003c/em\u003e, hypoplastic left heart syndrome; \u003cem\u003eMA\u003c/em\u003e, mitral atresia; \u003cem\u003eAA\u003c/em\u003e, aortic atresia; \u003cem\u003eMS\u003c/em\u003e, mitral stenosis; \u003cem\u003eAS\u003c/em\u003e, aortic stenosis; PAB, pulmonary artery banding; \u003cem\u003eRV-PA shunt\u003c/em\u003e, right ventricle to pulmonary artery shunt.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003eThe right ventricular function following the Norwood procedure is shown in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e. Echocardiography showed that the median RVFAC was 43% (range: 29\u0026ndash;53%). Cardiac catheterization showed that the CI was 3.4 L/min m\u003csup\u003e2\u003c/sup\u003e (range: 2.5\u0026ndash;4.9 L/min m\u003csup\u003e2\u003c/sup\u003e), RVEF was 53.5% (range: 32\u0026ndash;77%), and the pressure gradient from the ascending aorta to the descending aorta was 1 mmHg (0\u0026ndash;9 mmHg).\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eRight ventricular function after Norwood\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTime from Norwood to Glenn, \u003cem\u003emonths\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e4 (1\u0026ndash;20)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEchocardiogram\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRVFAC, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43 (29\u0026ndash;53)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCardiac catheterization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCardiac index, \u003cem\u003eL/min/m\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.4 (2.5\u0026ndash;4.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRVEF, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53.5 (32\u0026ndash;77)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRVESVI, \u003cem\u003eml/m\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60.9 (26.6\u0026ndash;98.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRVEDVI, \u003cem\u003eml/m\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e128.5 (102.5\u0026ndash;168.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRVESP, \u003cem\u003emmHg\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e76.5 (56.0\u0026ndash;87.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRVEDP, \u003cem\u003emmHg\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7.0 (2.0\u0026ndash;10.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePVR, \u003cem\u003eU・m\u003c/em\u003e\u003csup\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.4 (1.5\u0026ndash;4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026Delta;aAo-dAo, \u003cem\u003emmHg\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1 (0\u0026ndash;9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\"\u003eRVFAC, right ventricular fraction area changes; RVEF, right ventricular ejection fraction; RVESVI, right ventricular end-systolic ventricular volume index; RVEDVI, right ventricular end-diastolic volume index;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\n \u003ch2\u003eAortic arch geometry\u003c/h2\u003e\n \u003cp\u003eEnhanced CT was used for geometric analysis of the aortic arch. The diameters of the aAo, TA, iAo, and dAo were 10.6 mm (range: 7.4\u0026ndash;13.2 mm), 9.4 mm (range: 6.5\u0026ndash;12.5 mm), 5.3 mm (range: 3.0\u0026ndash;6.5 mm), and 6.5 mm (range: 5.0\u0026ndash;10.1 mm), respectively. The corresponding arch SD was 2.0 (1.4\u0026ndash;3.4) (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003e\u003c/p\u003e\u0026nbsp;\u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eGeometric analysis of aortic arch after Norwood\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAscending aorta, \u003cem\u003emm\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e10.6 (7.4\u0026ndash;13.2)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTransverse arch, \u003cem\u003emm\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.4 (6.5\u0026ndash;12.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAortic isthmus, \u003cem\u003emm\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.3 (3.0-6.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDescending aorta, \u003cem\u003emm\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6.5 (5.0-10.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cspan style=\"color: rgb(184, 49, 47);\"\u003eCoactation index\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u003cspan style=\"color: rgb(184, 49, 47);\"\u003e2.2 (1.9\u0026ndash;2.8)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eArch SD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.0 (1.4\u0026ndash;3.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\"\u003e\u003cem\u003eSD\u003c/em\u003e, standard deviation\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\n \u003ch2\u003eRelationship between right ventricular function and arch geometry\u003c/h2\u003e\n \u003cp\u003eThere was a significant negative correlation between arch SD and CI before the Glenn procedure (r\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.43, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Similarly, there was a significant negative relationship between arch SD and RVFAC before the Glenn procedure (r\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.46, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). After the Glenn procedure, no significant relationship between arch SD and CI was observed; however, there was a significant negative correlation between arch SD and RVFAC before the Fontan procedure (r\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;=\u0026thinsp;0.45, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eWe demonstrated that a smooth aortic arch morphology with minimal diameter discrepancies is essential for maintaining cardiac output and contraction before the Glenn procedure in patients with HLHS who underwent the Norwood procedure.\u003c/p\u003e \u003cp\u003eOur findings align with previous studies that reported increased afterload due to reCoA as a risk factor for right ventricular dysfunction or tricuspid valve regurgitation [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Even mild obstruction can lead to significant clinical issues and increased early mortality rates. Several studies have explored energy dynamics in this context [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Asada et al. reported that chimney reconstruction technique used during the Norwood procedure could reduce energy loss and maintain optimal blood flow. Similarly, Michal et al. found that a high degree of Norwood neo-aortic tapering was linked to increased energy loss, with energy losses in the high-degree group accounting for 0.7% of ventricular power generation, compared to 0.3% in the low-degree group. They concluded that oversizing of the Norwood neo-aortic reconstruction should be avoided, as it may lead to single-ventricle deterioration. This aligns with our findings that significant tapering in the aortic arch can adversely impact right ventricukar performance, leading to decrease CI and low RVEF. Although the precise impact of energy loss on right ventricular function remains unclear, our results suggest that high tapering, leading to high energy loss at the aortic arch, could impair right ventricular function.\u003c/p\u003e \u003cp\u003eWe used the chimney technique for neo-aortic reconstruction, facilitating horizontal plication and longitudinal extension of the neo-aortic trunk while preventing compression of the left pulmonary artery. This approach is designed to minimize energy loss. Burkhart et al. also proposed an interdigitating arch reconstruction technique to reduce reCoAe after the Norwood procedure [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], demonstrating that this technique could reduce afterload on the right ventricle by preventing aortic arch obstruction.\u003c/p\u003e \u003cp\u003eIn this study, the use of these two aortic reconstruction methods, along with autologous pericardial patching, appeared to contribute to minimal diameter discrepancy in the aortic arch, potentially reducing afterload on the right ventricle and energy loss. We found a significant correlation between diameter discrepancy, right ventricular function, and CI after the Norwood procedure, suggesting that minimizing diameter differences during the Norwood procedure could be crucial for maintaining right ventricular function before the Fontan operation.\u003c/p\u003e \u003cp\u003eThere were some limitations to this study. This is a single-center, retrospective cohort study with a small sample size. The patients who did not undergo Glenn procedure or died before Glenn procedure were not included. Right ventricular function in patients with HLHS is influenced by several complex factors, including valve function, collateral circularion, and coronary perfusion. The influence of aortic arch geometry on Fontan circulation over the long term should be explored further. Additionally, changes in arch geometry may occur at different stages post-Glenn and post-Fontan, and interventions could also alter the geometry.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eDuring the Norwood procedure, reconstruction of an unobstructed aortic arch without a significant diameter discrepancy appears to be a critical factor for maintaining right ventricular function and CI before the Glenn procedure. Further investigation are needed to understand the impact of aortic arch geometry on long-term Fontan circulation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eCompeting interests\u003c/strong\u003e \u003cp\u003eThe authors have no competing interests to declare that are relevant to the content of this article.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eT.K. and S.T. wrote the main manuscript text and K.M. and Y.T. prepared figures and Tables. All authors reviewed the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements:\u003c/h2\u003e \u003cp\u003eNone.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eOhye RG, Schranz D, D\u0026rsquo;Udekem Y (2016) Current Therapy for Hypoplastic Left Heart Syndrome and Related Single Ventricle Lesions. Circulation 134:1265\u0026ndash;1279. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1161/CIRCULATIONAHA.116.022816\u003c/span\u003e\u003cspan address=\"10.1161/CIRCULATIONAHA.116.022816\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTweddell JS, Hoffman GM, Fedderly RT, Berger S, Thomas JP Jr, Ghanayem NS, Kessel MW, Litwin SB (1999) Phenoxybenzamine improves systemic oxygen delivery after the Norwood procedure. Ann Thorac Surg 67:161\u0026ndash;167. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/s0003-4975(98)01266-1\u003c/span\u003e\u003cspan address=\"10.1016/s0003-4975(98)01266-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTanem J, Rudd N, Rauscher J, Scott A, Frommelt MA, Hill GD (2020) Survival After Norwood Procedure in High-Risk Patients. Ann Thorac Surg 109:828\u0026ndash;834. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.athoracsur.2019.07.070\u003c/span\u003e\u003cspan address=\"10.1016/j.athoracsur.2019.07.070\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFriedland-Little JM, Aiyagari R, Yu S, Donohue JE, Hirsch-Romano JC (2014) Survival Through Staged Palliation: Fate of Infants Supported by Extracorporeal Membrane Oxygenation After the Norwood Operation. Ann Thorac Surg 97:659\u0026ndash;665. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.athoracsur.2013.10.066\u003c/span\u003e\u003cspan address=\"10.1016/j.athoracsur.2013.10.066\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBartram U, Grunenfelder J, Van Praagh R (1997) Causes of death after the modified Norwood procedure: a study of 122 postmortem cases. Ann Thorac Surg 64:1795\u0026ndash;1802. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/s0003-4975(97)01041-2\u003c/span\u003e\u003cspan address=\"10.1016/s0003-4975(97)01041-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWeinberg PM, Chin AJ, Murphy JD, Pigott JD, Norwood WI (1986) Post-mortem echocardiography and tomographic anatomy of hypoplastic left heart syndrome after palliative surgery. Am J Cardiol 58:1228\u0026ndash;1232. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/0002-9149(86)90387-5\u003c/span\u003e\u003cspan address=\"10.1016/0002-9149(86)90387-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBurkhart HM, Ashburn DA, Konstantinov IE, De Oliviera NC, Benson L, Williams WG, Van Arsdell GS (2005) Interdigitating arch reconstruction eliminates recurrent coarctation after the Norwood procedure. J Thorac Cardiovasc Surg 130:61\u0026ndash;65. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jtcvs.2005.02.060\u003c/span\u003e\u003cspan address=\"10.1016/j.jtcvs.2005.02.060\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAsada S, Yamagishi M, Itatani K, Yaku H (2017) Chimney reconstruction of the aortic arch in the Norwood procedure. J Thorac Cardiovasc Surg. 154;e51-e54. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1053/j.optechstcvs.2019.10.004\u003c/span\u003e\u003cspan address=\"10.1053/j.optechstcvs.2019.10.004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchafer M, Di Maria MV, Jaggers J, Stone ML, Ivy DD, Barker AJ, Mitchell MB (2021) High-degree Norwood neoaortic tapering is associated with abnormal flow conduction and elevated flow-mediated energy loss. J Thorac Cardiovasc Surg 162:1791\u0026ndash;1804. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.jtcvs.2021.01.111\u003c/span\u003e\u003cspan address=\"10.1016/j.jtcvs.2021.01.111\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKobayashi Y, Kotani Y, Kuroko Y, Kawabata T, Sano S, Kasahara S (2020) Norwood procedure with right ventricle to pulmonary artery conduit: a single-centre 20-year experience. Eur J Cardiothorac Surg 58:230\u0026ndash;236. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/ejcts/ezaa041\u003c/span\u003e\u003cspan address=\"10.1093/ejcts/ezaa041\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlsoufi B, Sinha R, McCracken C, Figueroa J, Altin F, Kanter K (2018) Outcomes and risk factors associated with tricuspid valve repair in children with hypoplastic left heart syndrome. Eur J Cardiothorac Surg 54:993\u0026ndash;1000. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/ejcts/ezy198\u003c/span\u003e\u003cspan address=\"10.1093/ejcts/ezy198\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLarrazabal LA, Tierney ESS, Brown DW, Gauvreau K, Vida VL, Bergersen L, Pigula FA, del Nido PJ, Bacha EA (2008) Ventricular Function Deteriorates with recurrent coarctation in hypoplastic left heart syndrome. Ann Thorac Surg 86:869\u0026ndash;874. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.athoracsur.2008.04.074\u003c/span\u003e\u003cspan address=\"10.1016/j.athoracsur.2008.04.074\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\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":"hypoplastic left heart syndrome, Norwood procedure, arch reconstruction, cardiac index","lastPublishedDoi":"10.21203/rs.3.rs-4573212/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4573212/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe outcomes of patients with hypoplastic left heart syndrome (HLHS) have significantly improved in recent years due to the utilization of the Norwood procedure. Unobstructed outflow through the aortic arch is important for maintaining right ventricular function. Some reports have shown that an aortic arch with a high-degree tapering form leads to increased energy loss; however, the correlation between right ventricular function and the degree of aortic arch tapering remains unknown. This retrospective, single-center analysis aimed to investigate the impact of aortic arch tapering following the Norwood procedure on circulation dynamics and right ventricular function. During the study period, 14 patients who underwent the Norwood procedure for HLHS and enhanced computed tomography before the Glenn procedure were included. The median age of the patients at the time of the Norwood procedure was 30 days (25\u0026ndash;269 days), and the median weight was 3.0 kg (2.6\u0026ndash;4.4 kg). As an indicator of the degree of tapering of the aortic arch, we used the standard deviation (SD) of the diameters of the ascending aorta, transverse arch, isthmus, and descending aorta (arch SD). There was a significant negative correlation between the cardiac index and arch SD. Furthermore, there was a significant negative correlation between the right ventricular fractional area change and arch SD. In conclusion, an unobstructed and minimally tapered aortic arch is essential for maintaining optimal right ventricular function.\u003c/p\u003e","manuscriptTitle":"Influence of Aortic Arch Form on Right Ventricular Function After the Norwood Procedure","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-12 18:34:33","doi":"10.21203/rs.3.rs-4573212/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":"08f161b6-9e98-430e-be18-001ce0cadc90","owner":[],"postedDate":"July 12th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-07-12T18:34:35+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-12 18:34:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4573212","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4573212","identity":"rs-4573212","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}