Blood flow dynamics in the ascending aorta of patients with bicuspid aortic valve before and after transcatheter aortic valve replacement -A computational fluid dynamics study

Blood flow dynamics in the ascending aorta of patients with bicuspid aortic valve before and after transcatheter aortic valve replacement -A computational fluid dynamics study | 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 Blood flow dynamics in the ascending aorta of patients with bicuspid aortic valve before and after transcatheter aortic valve replacement -A computational fluid dynamics study Kang An, Fengwen Zhang, Wenbin Ouyang, Xiangbin Pan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4505725/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 20 Dec, 2024 Read the published version in BMC Cardiovascular Disorders → Version 1 posted 4 You are reading this latest preprint version Abstract Background: Abnormal blood flow patterns are known to contribute to the ascending aortic dilation in patients with bicuspid aortic valve (BAV). The present study elucidated the blood flow characteristics in the dilated ascending aorta before and after transcatheter aortic valve replacement (TAVR) using computational fluid dynamics (CFD) analysis. Methods: We performed CFD analysis in three BAV patients with ascending aortic dilation (maximum diameter ≥45mm) who underwent TAVR. The blood flow streamline was visualized to evaluate the pre- and post-operative flow velocity, severity of vortex and helix, and wall shear stress (WSS) in the ascending aorta. Results: Before the procedure, all three patients showed abnormal blood flow patterns, with vortex and helix in the ascending aorta. Regionally elevated WSS was also observed in the lateral or posterior ascending aortic wall. After the procedure, the blood flow patterns significantly improved, and the maximum WSS also decreased. Conclusion: Abnormal blood flow patterns and WSS appeared to improve after TAVR in BAV patients with ascending aortic dilation. The impact on the long-term aortic growth rate and the incidence of aortic dissection requires further studies. Transcatheter aortic valve replacement Computational fluid dynamics Bicuspid aortic valve Ascending aortic dilation. Figures Figure 1 Figure 2 Figure 3 Introduction Transcatheter aortic valve replacement (TAVR) has been approved as a therapy for severe aortic stenosis regardless of the surgical risk profile [ 1 , 2 ] . However, data for patients with bicuspid aortic valve (BAV) undergoing TAVR is limited. BAV encompasses several morphologies that may pose challenges to TAVR procedure, such as elliptical annulus, bulky and asymmetric calcification, and ascending aortic dilation. Among these, ascending aortic dilation is a common feature in patients with BAV. Both genetic (aortic wall fragility) and hemodynamic (abnormal blood flow patterns) factors appear to contribute to the BAV aortopathy. Current guidelines recommend a combined surgical aortic valve replacement (SAVR) and aortic surgery when the diameter exceeds 45mm to prevent aortic dissection or rupture [ 3 ] . However, this aggressive strategy remains debated. For patients undergoing TAVR, it is technically difficult to simultaneously repair the dilated ascending aorta. Therefore, understanding the prognosis of untreated ascending aorta in these patients is important. Recent developments in imaging have suggested that the blood flow dynamics in the ascending aorta may be a major contributor to the BAV aortopathy [ 4 , 5 ] . Computational fluid dynamics (CFD) is a useful tool that allows for the visualization of blood flow patterns [ 6 , 7 ] . The aim of the present study is to compare the blood flow patterns and wall shear stress (WSS) in the dilated ascending aorta in patients with BAV before and after TAVR procedure. Methods Study patients The present study was a pilot study of the randomized controlled trial “Comparison of self- and balloon-expandable valves in patients with ascending aortic dilation undergoing transcatheter aortic valve replacement: The AAD-CHOICE study” (NCT06009588). We identified three BAV patients with ascending aortic dilation (maximum diameter ≥ 45mm) who underwent TAVR at our center. All three patients experienced uneventful procedure and had detailed clinical data, including pre- and post-operative computed tomography angiography (CTA) and transthoracic echocardiography. We performed CFD analysis for these patients using CTA imaging. The study was approved by the institutional review board of Fuwai Hospital (date of review, 12 July 2023; approval number, 2023–2024), and the informed consents were obtained from all patients. Computational fluid dynamics analysis Aortic geometry and meshing The aortic blood flow lumen geometries before and after the TAVR procedure were extracted from CTA scans of each patient using the commercial software Materialise Mimics 21.0 (Leuven, Belgium), and 3D aorta model were created from digital imaging and communications in medicine (DICOM) imaging data. Computational meshes were created using the commercial software ANSYS-ICEM 16.2 (ANSYS, Inc., Canonsburg, PA, USA). The mesh contained approximately 1.5 million tetrahedral elements and 5 boundary-fitted prism layers. Boundary conditions and blood flow analysis Blood was considered as an incompressible Newtonian fluid with a density of 1.06×10 3 kg/m 3 and a viscosity of 3.5×10 − 3 Pa·s. The inlet flow velocity profiles at the orifice of the native aortic valve (pre-operative) or the transcatheter heart valve (THV) (post-operative) were acquired by echocardiography in real time with electrocardiogram. A zero pressure condition was imposed at the outlets (innominate artery, left carotid artery, left subclavian artery, and descending aorta). The flow stimulation was carried out over 2 cardiac cycles. Time step was set to 1×10 − 4 s and the convergence criterion was set to 1×10 − 4 . The blood flow visualization and analysis were conducted using the commercial software ANSYS FLUENT 16.2 (ANSYS, Inc., Canonsburg, PA, USA). Statistical analyses Continuous variables were expressed as means ± standard deviations unless otherwise specified, and categorical variables were expressed as counts and proportions. Statistical analyses were performed using the Statistical Package for Social Sciences, version 23.0 (SPSS, Inc, Chicago, Ill). Results Table 1 showed the patients’ baseline characteristics and preoperative CTA measurements. All three patients had BAV and maximum ascending aortic diameter ≥ 45mm. All experienced uneventful TAVR procedure and completed CTA and transthoracic echocardiography before the discharge. Table 1 Baseline characteristics Patient 1 Patient 2 Patient 3 Age, y 79 68 70 Gender Female Female Male Body mass index, kg/m 2 22.2 27.5 16.4 Hypertension Yes Yes No Diabetes mellitus No No No History of coronary artery disease No No No Bicuspid aortic valve fusion type Type 0 Type 1, L/R Type 2, L-N/R-N Pre-operative echocardiography Left ventricular ejection fraction, % 63 40 64 Peak aortic valve velocity, m/s 4.3 4.5 5.5 Mean aortic valve pressure gradient, mmHg 60 47 69 CTA-measured aortic dimensions Annulus diameter, mm 20.9 26.9 23.7 Sinotubular junction diameter, mm 30.5 33.4 32.4 Maximal ascending aortic diameter, mm 49.4 45.2 45.0 Aortic root angulation, ° 62 54 50 Valve size implanted, mm 23 26 23 Valve type implanted Taurus One Venus A KoKaValve Post-operative echocardiography Left ventricular ejection fraction, % 68 42 72 Peak aortic valve velocity, m/s 2.7 2.0 2.4 Mean aortic valve pressure gradient, mmHg 16 9 14 Paravalvular aortic insufficiency None Mild Mild CTA: computed tomography angiography. Figure 1 showed the data analysis for patient 1. The patient had a type 0 Siever’s BAV. Before the procedure, the transvalvular aortic flow was observed along the greater curvature of the ascending aorta, with the peak velocity of 4.3m/s. The vortex was observed in the ascending aorta. The maximum WSS was 16.7 Pa on the lateral side of the ascending aorta. A 23mm Taurus One THV was used (Peijia Medical, Suzhou, China). After the procedure, the aortic stenosis was corrected with the peak velocity of 2.7m/s and the mean pressure gradient of 16mmHg. The blood flow patterns significantly improved, and the maximum WSS also drastically decreased. Figure 2 showed the data analysis for patient 2. The patient had a type 1 Siever’s BAV (L/R). Before the procedure, the transvalvular aortic flow was observed along the posterior side of the ascending aorta, with the peak velocity of 4.5m/s. The blood flow was complex and tortuous, with abnormal helical flow appeared to dominate the ascending aorta. The maximum WSS was 12.2 Pa on the posterior side of the ascending aorta. A 26mm Venus-A THV was used (Venus MedTech, Hangzhou, China). After the procedure, the aortic stenosis was corrected with the peak velocity of 2.0m/s and the mean pressure gradient of 9mmHg. The blood flow patterns improved, and the maximum WSS also decreased. Figure 3 showed the data analysis for patient 3. The patient had a type 2 Siever’s BAV (L-N/R-N). Before the procedure, the transvalvular aortic flow was observed along the posterolateral side of the ascending aorta, with the peak velocity of 5.5m/s. A flow jet impinged against the posterior wall of the ascending aorta, in which the WSS was the greatest (14.5Pa). A 23mm KoKaValve THV was used (KOKA Lifesciences, Nantong, China). After the procedure, the aortic stenosis was corrected with the peak velocity of 2.4m/s and the mean pressure gradient of 14mmHg. The blood flow patterns and the WSS were improved. Discussion It remains disputed whether the aortic dilation that is commonly seen in patients with BAV is related to intrinsic aortic wall fragility or altered hemodynamics. Recent advancements in dynamic blood flow imaging provide detailed flow information. Previous studies showed that patients with BAV, even with normal aortic valves, had more eccentric ascending aortic blood flow compared with those with TAV [ 8 , 9 ] . When combining severe AS, the high velocity jet flow tends to exacerbate this abnormal hemodynamics [ 9 ] . In the present study, the preoperative blood flow showed marked helix or vortex in the ascending aorta, which was in accordance with previous studies. This abnormal flow pattern has been reported to be associated with regional elevation of WSS [ 9 , 10 ] . WSS reflects the friction that the blood flow exerts onto the aortic wall. The prolonged exposure to altered WWS is related to the dysregulation of extracellular matrix and the degeneration of elastic fibers of the aortic wall, which may contribute to aortic dilation and increase the risk of aortic dissection [ 11 , 12 ] . The present study also found regionally elevated WSS on greater curvature of the ascending aorta in all three patients before the procedure, which was in accordance with previous studies. After the TAVR procedure, we found that the abnormal flow patterns tended to normalize, and the WSS decreased significantly in all patients. This may have important long-term clinical implications, because WSS has been shown to be regionally increased at the site of aortic dilation and aneurysm formation [ 13 , 14 ] . We hypothesized that by reducing WSS and improving blood flow patterns, the risk of adverse aortic events might be decreased in the long term in patients with ascending aortic dilation who underwent TAVR. Our recent retrospective study showed that TAVR can be safely performed in patients with ascending aortic dilation (diameter ≥ 45mm), with a similar incidence of adverse aortic events as well as survival compared to those without [ 15 ] . Previous studies by Farag et al [ 16 ] and Trauzeddel et al [ 17 ] both reported that compared with healthy controls, eccentric distribution of blood flow still existed after TAVR. One explanation is that the THV is implanted inside the calcified native aortic valve, inevitably resulting in a smaller effective orifice area (EOA) compared with healthy aortic valve. However, neither study compared the blood flow patterns before and after the TAVR procedure. In our study, significant improvement of blood flow and WSS was observed after the procedure. Another study by Komoriyama et al [ 18 ] also reported that TAVR improves blood flow dynamics, especially when a larger EOA is obtained. Unfortunately, data regarding pre- and postoperative EOAs were not available in the present study. The impact of EOA on the blood flow changes and WSS after TAVR requires further studies. There are several limitations to the present study. First, the sample size is small. Subgroup analyses regarding the differences in blood flow dynamics were not available. These factors include different BAV fusion patterns, type of THVs (self- and balloon-expandable valves), and ascending aortic geometries. Second, similar to other CFD studies, we make a number of simplifications and assumptions. For example, the aortic wall dynamics was not simulated, and the boundary conditions for outlets were set as zero pressure. Third, blood flow patterns, including vortex and helix, were only assessed qualitatively. Further studies with quantification would be more accurate and objective. Fourth, the THVs used in the present study are locally manufactured valves that have received Chinese regulatory approval. Although several studies have reported the safety and efficiency of these valves [ 19 , 20 ] , further studies with large sample size and long-term follow-up are necessary. Finally, the impact of post-TAVR blood flow characteristics on the ascending aorta requires long-term follow-up. Therefore, the present study should be interpreted as a pilot study. In conclusion, abnormal blood flow patterns and WSS appeared to improve after TAVR in BAV patients with ascending aortic dilation. The impact on the long-term aortic growth rate and the incidence of aortic dissection requires further studies. Abbreviations BAV=bicuspid aortic valve CFD=computational fluid dynamic CTA=computed tomography angiography EOA=effective orifice area SAVR=surgical aortic valve replacement TAVR=transcatheter aortic valve replacement THV=transcatheter heart valve WSS=wall shear stress Declarations Acknowledgements None. Authors’ contributions All authors have read and approved the manuscript. Methodology and manuscript writing: K.A. and W.O. Data collection and analyses: K.A., F.Z., and W.O. Conceptualization and supervision: F.Z., W.O., and X.P. Funding The study was supported by The Fundamental Research Funds for the Central Universities (2019PT350005), National Natural Science Foundation of China (81970444), Beijing Municipal Science and Technology Project (Z201100005420030), National High Level Talents Special Support Plan (2020-RSW02), Sanming Project of Medicine in Shenzhen (SZSM202011013), and CAMS Innovation Fund for Medical Sciences (2021-I2M-1-065). Availability of data and materials The data that support the findings of this study are available from the corresponding author upon reasonable request. Ethical approval and consent to participate The study protocol complied with the Declaration of Helsinki and was approved by the institutional review board of Fuwai Hospital (date of review, 12 July 2023; approval number, 2023-2024), and the informed consents were obtained from all patients. Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests. References Ahmad Y, Howard JP, Arnold AD, et al (2023) Transcatheter versus surgical aortic valve replacement in lower-risk and higher-risk patients: a meta-analysis of randomized trials. Eur Heart J 44(10):836-852. Jørgensen TH, Thyregod HGH, Ihlemann N, et al (2021) Eight-year outcomes for patients with aortic valve stenosis at low surgical risk randomized to transcatheter vs. surgical aortic valve replacement. Eur Heart J 42(30):2912-2919. Otto CM, Nishimura RA, Bonow RO, et al (2021) 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 143(5):e72-e227. Edlin J, Nowell J, Arthurs C, et al (2021) Assessing the methodology used to study the ascending aorta haemodynamics in bicuspid aortic valve. Eur Heart J Digit Health 2(2):271-278. Hanigk M, Burgstaller E, Latus H et al (2023) Aortic wall shear stress in bicuspid aortic valve disease-10-year follow-up. Cardiovasc Diagn Ther 13(1):38-50. Jarral OA, Tan MKH, Salmasi MY et al (2020)Phase-contrast magnetic resonance imaging and computational fluid dynamics assessment of thoracic aorta blood flow: a literature review. Eur J Cardiothorac Surg 57(3):438-446. Cilla M, Casales M, Peña E, et al (2020) A parametric model for studying the aorta hemodynamics by means of the computational fluid dynamics. J Biomech 103:109691. Guzzardi DG, Barker AJ, van Ooij P et al (2015) Valve-Related Hemodynamics Mediate Human Bicuspid Aortopathy: Insights From Wall Shear Stress Mapping. J Am Coll Cardiol 66(8):892-900. Hope MD, Wrenn J, Sigovan M et al (2012) Imaging biomarkers of aortic disease: increased growth rates with eccentric systolic flow. J Am Coll Cardiol 60(4):356-357. Ha H, Koo HJ, Lee JG et al (2017) Association between flow skewness and aortic dilatation in patients with aortic stenosis. Int J Cardiovasc Imaging 33(12):1969-1978. Bollache E, Guzzardi DG, Sattari S et al (2018) Aortic valve-mediated wall shear stress is heterogeneous and predicts regional aortic elastic fiber thinning in bicuspid aortic valve-associated aortopathy. J Thorac Cardiovasc Surg 156(6):2112-2120.e2. Guala A, Dux-Santoy L, Teixido-Tura G et al (2022) Wall Shear Stress Predicts Aortic Dilation in Patients With Bicuspid Aortic Valve. JACC Cardiovasc Imaging 15(1):46-56. Hope MD, Hope TA, Meadows AK et al (2010) Bicuspid aortic valve: four-dimensional MR evaluation of ascending aortic systolic flow patterns. Radiology 55(1):53-61. Nordmeyer S, Hellmeier F, Yevtushenko P et al (2020) Abnormal aortic flow profiles persist after aortic valve replacement in the majority of patients with aortic valve disease: how model-based personalized therapy planning could improve results. A pilot study approach. Eur J Cardiothorac Surg 57(1):133-141. An K, Zhang F, Ouyang W et al (2023) Transcatheter aortic valve replacement in patients with preoperative ascending aortic diameter ≥45 mm. Cardiovasc Diagn Ther 13(6):939-947. Farag ES, Vendrik J, van Ooij P et al (2019) Transcatheter aortic valve replacement alters ascending aortic blood flow and wall shear stress patterns: A 4D flow MRI comparison with age-matched, elderly controls. Eur Radiol 29(3):1444-1451. Trauzeddel RF, Löbe U, Barker AJ et al (2016) Blood flow characteristics in the ascending aorta after TAVI compared to surgical aortic valve replacement. Int J Cardiovasc Imaging 32(3):461-467. Komoriyama H, Kamiya K, Nagai T et al (2021) Blood flow dynamics with four-dimensional flow cardiovascular magnetic resonance in patients with aortic stenosis before and after transcatheter aortic valve replacement. J Cardiovasc Magn Reson 23(1):81. Liao YB, Zhao ZG, Wei X et al (2017) Transcatheter aortic valve implantation with the self-expandable venus A-Valve and CoreValve devices: Preliminary Experiences in China. Catheter Cardiovasc Interv 89(S1):528-533. Zhou D, Pan W, Wang J et al (2020) VitaFlow™ transcatheter valve system in the treatment of severe aortic stenosis: One-year results of a multicenter study. Catheter Cardiovasc Interv 95(2):332-338. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 20 Dec, 2024 Read the published version in BMC Cardiovascular Disorders → Version 1 posted Editorial decision: Revision requested 20 Jun, 2024 Editor assigned by journal 19 Jun, 2024 Submission checks completed at journal 19 Jun, 2024 First submitted to journal 30 May, 2024 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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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-4505725","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":316751225,"identity":"8b366d6f-1edd-4a21-8b42-cd114de57328","order_by":0,"name":"Kang An","email":"","orcid":"","institution":"National Center for Cardiovascular Disease, China \u0026 Fuwai Hospital, Chinese Academy of Medical Sciences \u0026 Peking Union Medical College","correspondingAuthor":false,"prefix":"","firstName":"Kang","middleName":"","lastName":"An","suffix":""},{"id":316751226,"identity":"92e90f27-4ec8-4693-8df7-e8ffa9cd006d","order_by":1,"name":"Fengwen 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2","display":"","copyAsset":false,"role":"figure","size":384705,"visible":true,"origin":"","legend":"\u003cp\u003eThe computational fluid dynamics in patient 2.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4505725/v1/25a7611384172151902e672f.png"},{"id":60530128,"identity":"dc77f3a0-c537-4dfb-8908-6b578f3affb0","added_by":"auto","created_at":"2024-07-17 20:02:09","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":371751,"visible":true,"origin":"","legend":"\u003cp\u003eThe computational fluid dynamics in patient 3.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4505725/v1/922c35d3514265d8920088b4.png"},{"id":72201972,"identity":"184333ce-284d-48d4-9d1d-e59eafda701c","added_by":"auto","created_at":"2024-12-23 16:12:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2104986,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4505725/v1/246e241d-a6b2-4367-be4b-4d948305fba1.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Blood flow dynamics in the ascending aorta of patients with bicuspid aortic valve before and after transcatheter aortic valve replacement -A computational fluid dynamics study","fulltext":[{"header":"Introduction","content":"\u003cp\u003eTranscatheter aortic valve replacement (TAVR) has been approved as a therapy for severe aortic stenosis regardless of the surgical risk profile\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. However, data for patients with bicuspid aortic valve (BAV) undergoing TAVR is limited. BAV encompasses several morphologies that may pose challenges to TAVR procedure, such as elliptical annulus, bulky and asymmetric calcification, and ascending aortic dilation. Among these, ascending aortic dilation is a common feature in patients with BAV. Both genetic (aortic wall fragility) and hemodynamic (abnormal blood flow patterns) factors appear to contribute to the BAV aortopathy. Current guidelines recommend a combined surgical aortic valve replacement (SAVR) and aortic surgery when the diameter exceeds 45mm to prevent aortic dissection or rupture\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. However, this aggressive strategy remains debated. For patients undergoing TAVR, it is technically difficult to simultaneously repair the dilated ascending aorta. Therefore, understanding the prognosis of untreated ascending aorta in these patients is important.\u003c/p\u003e \u003cp\u003eRecent developments in imaging have suggested that the blood flow dynamics in the ascending aorta may be a major contributor to the BAV aortopathy\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. Computational fluid dynamics (CFD) is a useful tool that allows for the visualization of blood flow patterns\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. The aim of the present study is to compare the blood flow patterns and wall shear stress (WSS) in the dilated ascending aorta in patients with BAV before and after TAVR procedure.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eStudy patients\u003c/p\u003e \u003cp\u003eThe present study was a pilot study of the randomized controlled trial \u0026ldquo;Comparison of self- and balloon-expandable valves in patients with ascending aortic dilation undergoing transcatheter aortic valve replacement: The AAD-CHOICE study\u0026rdquo; (NCT06009588). We identified three BAV patients with ascending aortic dilation (maximum diameter\u0026thinsp;\u0026ge;\u0026thinsp;45mm) who underwent TAVR at our center. All three patients experienced uneventful procedure and had detailed clinical data, including pre- and post-operative computed tomography angiography (CTA) and transthoracic echocardiography. We performed CFD analysis for these patients using CTA imaging. The study was approved by the institutional review board of Fuwai Hospital (date of review, 12 July 2023; approval number, 2023\u0026ndash;2024), and the informed consents were obtained from all patients.\u003c/p\u003e \u003cp\u003eComputational fluid dynamics analysis\u003c/p\u003e \u003cp\u003eAortic geometry and meshing\u003c/p\u003e \u003cp\u003eThe aortic blood flow lumen geometries before and after the TAVR procedure were extracted from CTA scans of each patient using the commercial software Materialise Mimics 21.0 (Leuven, Belgium), and 3D aorta model were created from digital imaging and communications in medicine (DICOM) imaging data. Computational meshes were created using the commercial software ANSYS-ICEM 16.2 (ANSYS, Inc., Canonsburg, PA, USA). The mesh contained approximately 1.5\u0026nbsp;million tetrahedral elements and 5 boundary-fitted prism layers.\u003c/p\u003e \u003cp\u003eBoundary conditions and blood flow analysis\u003c/p\u003e \u003cp\u003eBlood was considered as an incompressible Newtonian fluid with a density of 1.06\u0026times;10\u003csup\u003e3\u003c/sup\u003ekg/m\u003csup\u003e3\u003c/sup\u003e and a viscosity of 3.5\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003ePa\u0026middot;s. The inlet flow velocity profiles at the orifice of the native aortic valve (pre-operative) or the transcatheter heart valve (THV) (post-operative) were acquired by echocardiography in real time with electrocardiogram. A zero pressure condition was imposed at the outlets (innominate artery, left carotid artery, left subclavian artery, and descending aorta). The flow stimulation was carried out over 2 cardiac cycles. Time step was set to 1\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003es and the convergence criterion was set to 1\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;4\u003c/sup\u003e. The blood flow visualization and analysis were conducted using the commercial software ANSYS FLUENT 16.2 (ANSYS, Inc., Canonsburg, PA, USA).\u003c/p\u003e \u003cp\u003eStatistical analyses\u003c/p\u003e \u003cp\u003eContinuous variables were expressed as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviations unless otherwise specified, and categorical variables were expressed as counts and proportions. Statistical analyses were performed using the Statistical Package for Social Sciences, version 23.0 (SPSS, Inc, Chicago, Ill).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e showed the patients\u0026rsquo; baseline characteristics and preoperative CTA measurements. All three patients had BAV and maximum ascending aortic diameter\u0026thinsp;\u0026ge;\u0026thinsp;45mm. All experienced uneventful TAVR procedure and completed CTA and transthoracic echocardiography before the discharge.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBaseline characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePatient 1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePatient 2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePatient 3\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, y\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody mass index, kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e27.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e16.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eYes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes mellitus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHistory of coronary artery disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBicuspid aortic valve fusion type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eType 0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eType 1, L/R\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eType 2, L-N/R-N\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePre-operative echocardiography\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft ventricular ejection fraction, %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePeak aortic valve velocity, m/s\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean aortic valve pressure gradient, mmHg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e69\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCTA-measured aortic dimensions\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAnnulus diameter, mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSinotubular junction diameter, mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e33.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e32.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaximal ascending aortic diameter, mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e49.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e45.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAortic root angulation, \u0026deg;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eValve size implanted, mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eValve type implanted\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTaurus One\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eVenus A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKoKaValve\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePost-operative echocardiography\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLeft ventricular ejection fraction, %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePeak aortic valve velocity, m/s\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMean aortic valve pressure gradient, mmHg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParavalvular aortic insufficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMild\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eCTA: computed tomography angiography.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e showed the data analysis for patient 1. The patient had a type 0 Siever\u0026rsquo;s BAV. Before the procedure, the transvalvular aortic flow was observed along the greater curvature of the ascending aorta, with the peak velocity of 4.3m/s. The vortex was observed in the ascending aorta. The maximum WSS was 16.7 Pa on the lateral side of the ascending aorta. A 23mm Taurus One THV was used (Peijia Medical, Suzhou, China). After the procedure, the aortic stenosis was corrected with the peak velocity of 2.7m/s and the mean pressure gradient of 16mmHg. The blood flow patterns significantly improved, and the maximum WSS also drastically decreased.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e showed the data analysis for patient 2. The patient had a type 1 Siever\u0026rsquo;s BAV (L/R). Before the procedure, the transvalvular aortic flow was observed along the posterior side of the ascending aorta, with the peak velocity of 4.5m/s. The blood flow was complex and tortuous, with abnormal helical flow appeared to dominate the ascending aorta. The maximum WSS was 12.2 Pa on the posterior side of the ascending aorta. A 26mm Venus-A THV was used (Venus MedTech, Hangzhou, China). After the procedure, the aortic stenosis was corrected with the peak velocity of 2.0m/s and the mean pressure gradient of 9mmHg. The blood flow patterns improved, and the maximum WSS also decreased.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e showed the data analysis for patient 3. The patient had a type 2 Siever\u0026rsquo;s BAV (L-N/R-N). Before the procedure, the transvalvular aortic flow was observed along the posterolateral side of the ascending aorta, with the peak velocity of 5.5m/s. A flow jet impinged against the posterior wall of the ascending aorta, in which the WSS was the greatest (14.5Pa). A 23mm KoKaValve THV was used (KOKA Lifesciences, Nantong, China). After the procedure, the aortic stenosis was corrected with the peak velocity of 2.4m/s and the mean pressure gradient of 14mmHg. The blood flow patterns and the WSS were improved.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIt remains disputed whether the aortic dilation that is commonly seen in patients with BAV is related to intrinsic aortic wall fragility or altered hemodynamics. Recent advancements in dynamic blood flow imaging provide detailed flow information. Previous studies showed that patients with BAV, even with normal aortic valves, had more eccentric ascending aortic blood flow compared with those with TAV\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. When combining severe AS, the high velocity jet flow tends to exacerbate this abnormal hemodynamics\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e. In the present study, the preoperative blood flow showed marked helix or vortex in the ascending aorta, which was in accordance with previous studies. This abnormal flow pattern has been reported to be associated with regional elevation of WSS\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. WSS reflects the friction that the blood flow exerts onto the aortic wall. The prolonged exposure to altered WWS is related to the dysregulation of extracellular matrix and the degeneration of elastic fibers of the aortic wall, which may contribute to aortic dilation and increase the risk of aortic dissection\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. The present study also found regionally elevated WSS on greater curvature of the ascending aorta in all three patients before the procedure, which was in accordance with previous studies.\u003c/p\u003e \u003cp\u003eAfter the TAVR procedure, we found that the abnormal flow patterns tended to normalize, and the WSS decreased significantly in all patients. This may have important long-term clinical implications, because WSS has been shown to be regionally increased at the site of aortic dilation and aneurysm formation\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. We hypothesized that by reducing WSS and improving blood flow patterns, the risk of adverse aortic events might be decreased in the long term in patients with ascending aortic dilation who underwent TAVR. Our recent retrospective study showed that TAVR can be safely performed in patients with ascending aortic dilation (diameter\u0026thinsp;\u0026ge;\u0026thinsp;45mm), with a similar incidence of adverse aortic events as well as survival compared to those without\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePrevious studies by Farag et al\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e and Trauzeddel et al\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e both reported that compared with healthy controls, eccentric distribution of blood flow still existed after TAVR. One explanation is that the THV is implanted inside the calcified native aortic valve, inevitably resulting in a smaller effective orifice area (EOA) compared with healthy aortic valve. However, neither study compared the blood flow patterns before and after the TAVR procedure. In our study, significant improvement of blood flow and WSS was observed after the procedure. Another study by Komoriyama et al\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e also reported that TAVR improves blood flow dynamics, especially when a larger EOA is obtained. Unfortunately, data regarding pre- and postoperative EOAs were not available in the present study. The impact of EOA on the blood flow changes and WSS after TAVR requires further studies.\u003c/p\u003e \u003cp\u003eThere are several limitations to the present study. First, the sample size is small. Subgroup analyses regarding the differences in blood flow dynamics were not available. These factors include different BAV fusion patterns, type of THVs (self- and balloon-expandable valves), and ascending aortic geometries. Second, similar to other CFD studies, we make a number of simplifications and assumptions. For example, the aortic wall dynamics was not simulated, and the boundary conditions for outlets were set as zero pressure. Third, blood flow patterns, including vortex and helix, were only assessed qualitatively. Further studies with quantification would be more accurate and objective. Fourth, the THVs used in the present study are locally manufactured valves that have received Chinese regulatory approval. Although several studies have reported the safety and efficiency of these valves\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e, further studies with large sample size and long-term follow-up are necessary. Finally, the impact of post-TAVR blood flow characteristics on the ascending aorta requires long-term follow-up. Therefore, the present study should be interpreted as a pilot study.\u003c/p\u003e \u003cp\u003eIn conclusion, abnormal blood flow patterns and WSS appeared to improve after TAVR in BAV patients with ascending aortic dilation. The impact on the long-term aortic growth rate and the incidence of aortic dissection requires further studies.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eBAV=bicuspid aortic valve\u003c/p\u003e\n\u003cp\u003eCFD=computational fluid dynamic\u003c/p\u003e\n\u003cp\u003eCTA=computed tomography angiography\u003c/p\u003e\n\u003cp\u003eEOA=effective orifice area\u003c/p\u003e\n\u003cp\u003eSAVR=surgical aortic valve replacement\u003c/p\u003e\n\u003cp\u003eTAVR=transcatheter aortic valve replacement\u003c/p\u003e\n\u003cp\u003eTHV=transcatheter heart valve\u003c/p\u003e\n\u003cp\u003eWSS=wall shear stress\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026rsquo; contributions\u003c/p\u003e\n\u003cp\u003eAll authors have read and approved the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMethodology and manuscript writing: K.A. and W.O.\u003c/p\u003e\n\u003cp\u003eData collection and analyses: K.A., F.Z., and W.O.\u003c/p\u003e\n\u003cp\u003eConceptualization and supervision: F.Z., W.O., and X.P.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThe study was supported by\u0026nbsp;The Fundamental Research Funds for the Central Universities (2019PT350005), National Natural Science Foundation of China (81970444), Beijing Municipal Science and Technology Project (Z201100005420030), National High Level Talents Special Support Plan (2020-RSW02),\u0026nbsp;Sanming Project of Medicine in Shenzhen (SZSM202011013), and\u0026nbsp;CAMS Innovation Fund for Medical Sciences\u0026nbsp;(2021-I2M-1-065).\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003eEthical approval and consent to participate\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe study protocol complied with the Declaration of Helsinki and was approved by the institutional review board of Fuwai Hospital (date of review, 12 July 2023; approval number, 2023-2024), and the informed consents were obtained from all patients.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAhmad Y, Howard JP, Arnold AD, et al (2023) Transcatheter versus surgical aortic valve replacement in lower-risk and higher-risk patients: a meta-analysis of randomized trials. Eur Heart J 44(10):836-852.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eJ\u0026oslash;rgensen TH, Thyregod HGH, Ihlemann N, et al (2021) Eight-year outcomes for patients with aortic valve stenosis at low surgical risk randomized to transcatheter vs. surgical aortic valve replacement. Eur Heart J 42(30):2912-2919.\u003c/li\u003e\n \u003cli\u003eOtto CM, Nishimura RA, Bonow RO, et al (2021) 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 143(5):e72-e227.\u003c/li\u003e\n \u003cli\u003eEdlin J, Nowell J, Arthurs C, et al (2021) Assessing the methodology used to study the ascending aorta haemodynamics in bicuspid aortic valve. Eur Heart J Digit Health 2(2):271-278.\u003c/li\u003e\n \u003cli\u003eHanigk M, Burgstaller E, Latus H et al (2023) Aortic wall shear stress in bicuspid aortic valve disease-10-year follow-up. Cardiovasc Diagn Ther 13(1):38-50.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eJarral OA, Tan MKH, Salmasi MY et al (2020)Phase-contrast magnetic resonance imaging and computational fluid dynamics assessment of thoracic aorta blood flow: a literature review. Eur J Cardiothorac Surg 57(3):438-446.\u003c/li\u003e\n \u003cli\u003eCilla M, Casales M, Pe\u0026ntilde;a E, et al (2020) A parametric model for studying the aorta hemodynamics by means of the computational fluid dynamics. J Biomech 103:109691.\u003c/li\u003e\n \u003cli\u003eGuzzardi DG, Barker AJ, van Ooij P et al (2015) Valve-Related Hemodynamics Mediate Human Bicuspid Aortopathy: Insights From Wall Shear Stress Mapping. J Am Coll Cardiol 66(8):892-900.\u003c/li\u003e\n \u003cli\u003eHope MD, Wrenn J, Sigovan M et al (2012) Imaging biomarkers of aortic disease: increased growth rates with eccentric systolic flow. J Am Coll Cardiol 60(4):356-357.\u003c/li\u003e\n \u003cli\u003eHa H, Koo HJ, Lee JG et al (2017) Association between flow skewness and aortic dilatation in patients with aortic stenosis. Int J Cardiovasc Imaging 33(12):1969-1978.\u003c/li\u003e\n \u003cli\u003eBollache E, Guzzardi DG, Sattari S et al (2018) Aortic valve-mediated wall shear stress is heterogeneous and predicts regional aortic elastic fiber thinning in bicuspid aortic valve-associated aortopathy. J Thorac Cardiovasc Surg 156(6):2112-2120.e2.\u003c/li\u003e\n \u003cli\u003eGuala A, Dux-Santoy L, Teixido-Tura G et al (2022) Wall Shear Stress Predicts Aortic Dilation in Patients With Bicuspid Aortic Valve. JACC Cardiovasc Imaging 15(1):46-56.\u003c/li\u003e\n \u003cli\u003eHope MD, Hope TA, Meadows AK et al (2010) Bicuspid aortic valve: four-dimensional MR evaluation of ascending aortic systolic flow patterns. Radiology 55(1):53-61.\u003c/li\u003e\n \u003cli\u003eNordmeyer S, Hellmeier F, Yevtushenko P et al (2020) Abnormal aortic flow profiles persist after aortic valve replacement in the majority of patients with aortic valve disease: how model-based personalized therapy planning could improve results. A pilot study approach. Eur J Cardiothorac Surg 57(1):133-141.\u003c/li\u003e\n \u003cli\u003eAn K, Zhang F, Ouyang W et al (2023) Transcatheter aortic valve replacement in patients with preoperative ascending aortic diameter \u0026ge;45 mm. Cardiovasc Diagn Ther 13(6):939-947.\u003c/li\u003e\n \u003cli\u003eFarag ES, Vendrik J, van Ooij P et al (2019) Transcatheter aortic valve replacement alters ascending aortic blood flow and wall shear stress patterns: A 4D flow MRI comparison with age-matched, elderly controls. Eur Radiol 29(3):1444-1451.\u003c/li\u003e\n \u003cli\u003eTrauzeddel RF, L\u0026ouml;be U, Barker AJ et al (2016) Blood flow characteristics in the ascending aorta after TAVI compared to surgical aortic valve replacement. Int J Cardiovasc Imaging 32(3):461-467.\u003c/li\u003e\n \u003cli\u003eKomoriyama H, Kamiya K, Nagai T et al (2021) Blood flow dynamics with four-dimensional flow cardiovascular magnetic resonance in patients with aortic stenosis before and after transcatheter aortic valve replacement. J Cardiovasc Magn Reson 23(1):81.\u003c/li\u003e\n \u003cli\u003eLiao YB, Zhao ZG, Wei X et al (2017) Transcatheter aortic valve implantation with the self-expandable venus A-Valve and CoreValve devices: Preliminary Experiences in China. Catheter Cardiovasc Interv 89(S1):528-533.\u003c/li\u003e\n \u003cli\u003eZhou D, Pan W, Wang J et al (2020) VitaFlow\u0026trade; transcatheter valve system in the treatment of severe aortic stenosis: One-year results of a multicenter study. Catheter Cardiovasc Interv 95(2):332-338.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Transcatheter aortic valve replacement, Computational fluid dynamics, Bicuspid aortic valve, Ascending aortic dilation.","lastPublishedDoi":"10.21203/rs.3.rs-4505725/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4505725/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eAbnormal blood flow patterns are known to contribute to the ascending aortic dilation in patients with bicuspid aortic valve (BAV). The present study elucidated the blood flow characteristics in the dilated ascending aorta before and after transcatheter aortic valve replacement (TAVR) using computational fluid dynamics (CFD) analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eWe performed CFD analysis in three BAV patients with ascending aortic dilation (maximum diameter ≥45mm) who underwent TAVR. The blood flow streamline was visualized to evaluate the pre- and post-operative flow velocity, severity of vortex and helix, and wall shear stress (WSS) in the ascending aorta.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Before the procedure, all three patients showed abnormal blood flow patterns, with vortex and helix in the ascending aorta. Regionally elevated WSS was also observed in the lateral or posterior ascending aortic wall. After the procedure, the blood flow patterns significantly improved, and the maximum WSS also decreased.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eAbnormal blood flow patterns and WSS appeared to improve after TAVR in BAV patients with ascending aortic dilation. The impact on the long-term aortic growth rate and the incidence of aortic dissection requires further studies.\u003c/p\u003e","manuscriptTitle":"Blood flow dynamics in the ascending aorta of patients with bicuspid aortic valve before and after transcatheter aortic valve replacement -A computational fluid dynamics study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-17 20:02:04","doi":"10.21203/rs.3.rs-4505725/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-06-20T08:19:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-19T11:41:32+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-06-19T11:39:59+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Cardiovascular Disorders","date":"2024-05-31T02:34:18+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"dbddb57b-d6d2-4c87-afb1-ee29e307fcc3","owner":[],"postedDate":"July 17th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-12-23T16:05:01+00:00","versionOfRecord":{"articleIdentity":"rs-4505725","link":"https://doi.org/10.1186/s12872-024-04394-w","journal":{"identity":"bmc-cardiovascular-disorders","isVorOnly":false,"title":"BMC Cardiovascular Disorders"},"publishedOn":"2024-12-20 15:58:19","publishedOnDateReadable":"December 20th, 2024"},"versionCreatedAt":"2024-07-17 20:02:04","video":"","vorDoi":"10.1186/s12872-024-04394-w","vorDoiUrl":"https://doi.org/10.1186/s12872-024-04394-w","workflowStages":[]},"version":"v1","identity":"rs-4505725","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4505725","identity":"rs-4505725","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}