Pulmonary Valve and Supravalvular Membrane Fusion Forming a Pouch-like Configuration: A Case Report

Pulmonary Valve and Supravalvular Membrane Fusion Forming a Pouch-like Configuration: A Case Report | 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 Case Report Pulmonary Valve and Supravalvular Membrane Fusion Forming a Pouch-like Configuration: A Case Report Xia Chen, Aoli Huang, Xujing Zhu, Renyuan Li This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8345329/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 14 You are reading this latest preprint version Abstract Background : Isolated congenital supravalvular pulmonary stenosis is an exceedingly rare cardiac anomaly, typically characterized by a discrete membrane above the valve obstructing the main pulmonary artery. We present a previously unreported anatomical variation in which this membrane fused with one of the pulmonary valve leaflets, forming a distinct pouch-like configuration. Case Presentation : A 44-year-old male presented with progressive exertional dyspnea. Preoperative echocardiography identified severe pulmonary stenosis and an obstructing supravalvular membrane, with a peak transvalvular gradient of 170 mmHg. Intraoperative exploration revealed that the pulmonary valve is trileaflet, with visibly thickened and fused commissures, causing severe pulmonary valve stenosis. Uniquely, the supravalvular pulmonary membrane fused with one leaflet forming a pouch-like configuration. Surgical separation of the fused commissures was performed, which successfully relieved the obstruction. The patient recovered well and reported complete symptom resolution at one-month follow-up. Conclusion : This case presents a unique anatomical variant of isolated congenital supravalvular pulmonary stenosis, characterized by fusion between the abnormal supravalvular membrane and one valve leaflet. The surgical approach adopted achieved acceptable results and substantially improved the patient's clinical condition. supravalvular pulmonary stenosis commissure fusion supravalvular membrane Figures Figure 1 Figure 2 Background Supravalvular pulmonary stenosis (SPS) is typically associated with complex congenital heart diseases, such as tetralogy of Fallot, transposition of the great arteries, and atrial or ventricular septal defects(1). Isolated SPS is usually acquired and develops following surgical interventions on the main pulmonary artery. Isolated congenital SPS is exceedingly rare(1, 2), which is characterized by a ring membrane-like structure above the pulmonary valve causing obstruction. Herein, we report an extremely unusual case of isolated congenital SPS in which a single membrane-like structure fused with one of the pulmonary valve leaflets, forming a pouch-like configuration. Case Presentation A 44-year-old male who presented with exertional dyspnea in the absence of cyanosis was admitted to our hospital. The symptom initially occurred one year ago after running and was relieved by rest. Over the past year, the patient perceived a progressive decline in exercise tolerance, prompting his visit to our outpatient clinic. Physical examination revealed a grade IV ejection systolic murmur with systolic thrill in the second left intercostal space. The electrocardiogram indicates sinus rhythm with complete right bundle branch block. The transthoracic echocardiography (TTE) identified a hyperechoic membrane located approximately 6 mm above the pulmonary valve (Fig. 1 A), with a central gap measuring about 4.7 mm in width (Fig. 1 B). Severe pulmonary valve stenosis with hypertrophied RV and mild tricuspid regurgitation were observed. The pulmonary valve annulus diameter was approximately 23 mm, and the main pulmonary artery diameter was 32 mm. Pulsed-wave Doppler (PWD) recorded a peak systolic flow velocity across the pulmonary valve of 6.5 m/s, corresponding to an estimated peak systolic gradient of about 170 mmHg. Computed tomography angiography (CTA) of the pulmonary arteries confirmed aneurysmal dilation of the main pulmonary artery and the left pulmonary artery (Fig. 1 C). The patient underwent median sternotomy for open-heart surgery. Interestingly, intraoperative exploration revealed that the lesion was not merely a supravalvular pulmonary membrane. Upon direct inspection, we found that the pulmonary valve was tricuspid with markedly thickened leaflets (Fig. 2 A), and the commissures were fused, resulting in severe pulmonary valve stenosis. Uniquely, a supravalvular membrane fused with one of the pulmonary valve leaflets, forming a pouch-like configuration (Fig. 2 B), which restricted leaflet mobility and collectively contributed to the severe obstruction. The fused commissures were incised to enlarge the valve orifice. Following successful weaning from cardiopulmonary bypass and resumption of cardiac activity, intraoperative transesophageal echocardiography demonstrated a significant decrease in pulmonary valve flow velocity compared to the preoperative measurement. The patient was subsequently transferred to the intensive care unit for one day. He had an uneventful recovery and was discharged 7 days after the operation. At the one-month outpatient follow-up, the patient reported complete resolution of previous exertional chest tightness and significant improvement in exercise tolerance. PWD measurement showed a peak systolic flow velocity across the pulmonary valve of 3.9 m/s, corresponding to an estimated peak systolic gradient of approximately 60 mmHg. Discussion SPS is a rare anomaly that can occur at any level in the pulmonary artery—from the main trunk to branches. Acquired SPS typically develops following surgical procedures involving the main pulmonary artery, while congenital SPS is commonly associated with syndromes such as congenital rubella, Noonan, and Williams syndromes( 1 ). Isolated congenital SPS represents the rarest form of pulmonary stenosis( 2 , 3 ). A study by Yuan et al( 4 ). reported that only 4 out of 333 SPS cases (1.2%) were isolated congenital SPS. Similarly, Kumar et al( 2 ). documented encountering merely 4 cases (0.08%) of isolated congenital SPS among 4,231 congenital cardiac surgeries performed. The defining morphological feature of isolated congenital SPS is a hypertrophied, stenotic tissue ring located at the sinotubular junction of the main pulmonary artery. In most cases, the pulmonary valve leaflets will exhibit secondary thickening due to persistent high-velocity jet flow impingement. This condition is frequently misdiagnosed as pulmonary valve stenosis on TTE, with definitive diagnosis typically requiring cardiac angiography. In the present case, preoperative TTE identified only a discrete supravalvular pulmonary membrane, failing to detect the unique malformation in which this membrane was fused with one of the pulmonary valve leaflets, thereby forming a pouch-like structure. To the best of our knowledge, this specific anatomical variant has not been previously documented in the medical literature. Surgical intervention is the primary treatment for SPS when patients become symptomatic or present with severe stenosis. For the commonly encountered annular membrane-induced SPS, membrane resection is the standard approach. For instance, Gourav et al( 1 ). successfully relieved supravalvular pulmonary stenosis in a 1-year-old infant by complete excision of the membrane. Alternatively, Bacha et al( 5 ). proposed a technique involving resection of the stenotic ring and reconstruction of the sinotubular junction using autologous tissues. They reported zero early or mid-term mortality in eight SPS cases (four of which were isolated SPS) repaired with this method, with no reinterventions required during a 22-month follow-up period( 5 ). Furthermore, the study by Dogan et al( 6 ). demonstrated that repair of isolated SPS using an oval pericardial or Dacron patch also yields excellent clinical outcomes. Interestingly, Mukawa et al( 7 ). also achieved favorable results by remodeling the pulmonary root using a modified Yacoub technique in an adult patient with symptomatic SPS following pulmonary artery banding performed in childhood. Given the rarity of isolated congenital SPS, long-term follow-up data remain scarce, making it difficult to draw definitive conclusions regarding reintervention rates. In the present case, the unique fusion of the membrane with a pulmonary valve leaflet, forming a pouch-like structure, precluded conventional membrane resection. Therefore, we performed simple commissurotomy at the fused pulmonary valve commissure to relieve the valvular stenosis. The patient remained asymptomatic during follow-up evaluations. Although the postoperative transvalvular gradient remains at 60 mmHg, given the preoperative gradient as high as 170 mmHg and the significant leaflet thickening with commissural fusion, simple commissurotomy has substantially reduced the hemodynamic burden, achieving complete symptom resolution and improved quality of life. The residual gradient may be attributed to leaflet fibrosis, thickening, and secondary changes, which limit complete leaflet expansion and mobility. In such cases, more aggressive surgical approaches—such as pulmonary valve replacement or complex leaflet reconstruction techniques—could entail greater operative risks. Moreover, preserving the patient's native valve structure is advantageous for long-term valve function and simplifies anticoagulation management, particularly in this young patient. This case highlights that for complex anatomical variants involving fusion between a supravalvular membrane and a valve leaflet, preoperative imaging may not fully reveal the three-dimensional morphology and the extent of fusion. Intraoperative exploration therefore becomes crucial in determining the definitive surgical strategy. In the future, incorporating three-dimensional transesophageal echocardiography or cardiac magnetic resonance imaging may facilitate more precise preoperative planning. Should symptoms recur or progress, further surgical( 7 ) or interventional options( 8 ) could be considered. In summary, this case demonstrates a rare anatomical variant of isolated congenital SPS, the treatment of which requires individualized surgical planning. Despite the presence of a residual gradient postoperatively, the symptomatic relief and hemodynamic improvement achieved through commissurotomy have led to an acceptable early clinical outcome. Abbreviations SPS, supravalvular pulmonary stenosis TTE, transthoracic echocardiography PWD, pulsed-wave Doppler CTA, computed tomography angiography SPM, supravalvular pulmonary membrane PV, pulmonary valve RVOT, right ventricular outflow tract MPA, main pulmonary artery LPA, left pulmonary artery Declarations Ethics approval and consent to participate The study was reviewed and approved by the Ethics Committee of the First Affiliated Hospital, School of Medicine, Zhejiang University. The patient provided her written informed consent to participate in this study. Consent for publication Written informed consent was obtained from the patient for the publication of this case report. Availability of data and materials The data and materials used during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare no financial or non-financial competing interests. Funding None. Authors' contributions XC and ALH wrote the original manuscript and prepared all figures; XJZ and RYL reviewed the manuscript; RYL performed the surgery and administrated the study. All authors read and approved the final manuscript. Acknowledgements Not applicable. References Gourav KP, Guha Niyogi S, Negi S, Amburu V. Supravalvular pulmonary stenosis caused by a membrane in the main pulmonary artery. Eur Heart J Cardiovasc Imaging. 2020;21(10):1173. Kumar V, Mahajan S, Jaswal V, Thingnam SKS. Surgical outcome of isolated congenital supravalvular pulmonary stenosis: a case series. Eur Heart J Case Rep. 2019;3(2). Milo S, Fiegel A, Shem-Tov A, Neufeld HN, Goor DA. Hour-glass deformity of the pulmonary valve: a third type of pulmonary valve stenosis. Br Heart J. 1988;60(2):128-33. Yuan SM. Supravalvular pulmonary stenosis: Congenital versus acquired. Acta Medica Mediterranea. 2017;33:849-56. Bacha EA, Kalimi R, Starr JP, Quinones J, Koenig P. Autologous repair of supravalvar pulmonic stenosis. Ann Thorac Surg. 2004;77(2):734-6. Dogan OF, Demircin M, Ozkutlu S, Pasaoglu I. Surgical management of infants with isolated supravalvular pulmonary stenosis: case reports. Heart Surg Forum. 2006;9(4):E668-74; discussion E73-4. Mukawa K, Iba Y, Kawaharada N. Pulmonary root remodeling procedure for symptomatic supravalvular pulmonary stenosis in an adult patient who underwent pulmonary artery banding: a case report. BMC Cardiovasc Disord. 2024;24(1):619. Cagdas M, Cinar T, Karabag Y, Rencuzogullari I. Successful treatment of supravalvular pulmonary membranous stenosis with percutaneous balloon valvuloplasty. Acta Cardiol. 2020;75(5):473-4. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 05 Apr, 2026 Reviews received at journal 09 Feb, 2026 Reviewers agreed at journal 07 Feb, 2026 Reviews received at journal 06 Feb, 2026 Reviewers agreed at journal 05 Feb, 2026 Reviews received at journal 05 Feb, 2026 Reviewers agreed at journal 05 Feb, 2026 Reviews received at journal 04 Feb, 2026 Reviewers agreed at journal 04 Feb, 2026 Reviewers agreed at journal 03 Feb, 2026 Reviewers invited by journal 03 Feb, 2026 Editor assigned by journal 22 Dec, 2025 Submission checks completed at journal 22 Dec, 2025 First submitted to journal 12 Dec, 2025 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-8345329","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":586546960,"identity":"ff84b556-e5ea-408c-b806-568704b124d1","order_by":0,"name":"Xia Chen","email":"","orcid":"","institution":"First Affiliated Hospital Zhejiang University","correspondingAuthor":false,"prefix":"","firstName":"Xia","middleName":"","lastName":"Chen","suffix":""},{"id":586546961,"identity":"fafbdb44-bf41-467d-a107-33924f2ffe6c","order_by":1,"name":"Aoli Huang","email":"","orcid":"","institution":"First Affiliated Hospital Zhejiang University","correspondingAuthor":false,"prefix":"","firstName":"Aoli","middleName":"","lastName":"Huang","suffix":""},{"id":586546962,"identity":"ae166f7e-7cbf-43a8-a35b-02fc85355b9f","order_by":2,"name":"Xujing Zhu","email":"","orcid":"","institution":"First Affiliated Hospital Zhejiang University","correspondingAuthor":false,"prefix":"","firstName":"Xujing","middleName":"","lastName":"Zhu","suffix":""},{"id":586546963,"identity":"c6492297-515a-4f00-8767-5031ebe755e9","order_by":3,"name":"Renyuan Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA10lEQVRIiWNgGAWjYJADxgcMBiRqYTYgWQubBFHKzNt7j0nz1NyxN7iRY1b5o+COPAP74aMb8GmROXMuTZrn2DNmkJbbPAbPDBt40tJu4NMiIZFjJs3DdpgNrIXB4DBjgwSPGX4t8m+AWv4d5gFpKfxhcNiesBagAmnetsMSIC0MPAaHEwlr4ckxtpzbd9hA8syzYmmgluQ2gn5hP2N44823w/Z8x5M3fvzx57BtP/vhY3i1AAELODoULmRA4pGNgHIQYP4AIuX7jz8gQvEoGAWjYBSMRAAAviNIqVHZS5oAAAAASUVORK5CYII=","orcid":"","institution":"First Affiliated Hospital Zhejiang University","correspondingAuthor":true,"prefix":"","firstName":"Renyuan","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2025-12-12 11:38:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8345329/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8345329/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":102182139,"identity":"aaa6c642-944e-4119-812d-1889c0ad4a1a","added_by":"auto","created_at":"2026-02-09 07:27:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":574550,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePreoperative imaging.\u003c/strong\u003e \u003cstrong\u003eA\u003c/strong\u003e and \u003cstrong\u003eB\u003c/strong\u003e Transthoracic echocardiography illustrates the location and the anatomic relationship of the SPM to the PV; \u003cstrong\u003eC\u003c/strong\u003e. Computed tomography angiography of the pulmonary arteries shows the dilation of the MPA and the LPA. \u003cem\u003eSPM, supravalvular pulmonary membrane; PV, pulmonary valve; RVOT, right ventricular outflow tract; MPA, main pulmonary artery; LPA, left pulmonary artery.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-8345329/v1/aa1eaf65beacbd6c9a6e5eaa.png"},{"id":102182140,"identity":"1a965640-df2b-45bd-9225-d560041d6680","added_by":"auto","created_at":"2026-02-09 07:27:56","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1036780,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIntraoperative findings.\u003c/strong\u003e \u003cstrong\u003eA\u003c/strong\u003e demonstrates that the PV is trileaflet, with visibly thickened and fused commissures (incised already); \u003cstrong\u003eB\u003c/strong\u003e shows the SPM and PV fusion forming a pouch-like configuration (yellow arrow).\u003cem\u003e SPM, supravalvular pulmonary membrane; PV, pulmonary valve.\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-8345329/v1/7724a21b36d57790c18825aa.png"},{"id":102182178,"identity":"f62d8e5e-5e22-486f-b789-677ef0c95318","added_by":"auto","created_at":"2026-02-09 07:28:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1968406,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8345329/v1/9e947e86-4d78-41e6-a291-59d8d5e44bb8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Pulmonary Valve and Supravalvular Membrane Fusion Forming a Pouch-like Configuration: A Case Report","fulltext":[{"header":"Background","content":"\u003cp\u003eSupravalvular pulmonary stenosis (SPS) is typically associated with complex congenital heart diseases, such as tetralogy of Fallot, transposition of the great arteries, and atrial or ventricular septal defects(1). Isolated SPS is usually acquired and develops following surgical interventions on the main pulmonary artery. Isolated congenital SPS is exceedingly rare(1, 2), which is characterized by a ring membrane-like structure above the pulmonary valve causing obstruction.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHerein, we report an extremely unusual case of isolated congenital SPS in which a single membrane-like structure fused with one of the pulmonary valve leaflets, forming a pouch-like configuration.\u0026nbsp;\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 44-year-old male who presented with exertional dyspnea in the absence of cyanosis was admitted to our hospital. The symptom initially occurred one year ago after running and was relieved by rest. Over the past year, the patient perceived a progressive decline in exercise tolerance, prompting his visit to our outpatient clinic. Physical examination revealed a grade IV ejection systolic murmur with systolic thrill in the second left intercostal space. The electrocardiogram indicates sinus rhythm with complete right bundle branch block. The transthoracic echocardiography (TTE) identified a hyperechoic membrane located approximately 6 mm above the pulmonary valve (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eA), with a central gap measuring about 4.7 mm in width (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eB). Severe pulmonary valve stenosis with hypertrophied RV and mild tricuspid regurgitation were observed. The pulmonary valve annulus diameter was approximately 23 mm, and the main pulmonary artery diameter was 32 mm. Pulsed-wave Doppler (PWD) recorded a peak systolic flow velocity across the pulmonary valve of 6.5 m/s, corresponding to an estimated peak systolic gradient of about 170 mmHg. Computed tomography angiography (CTA) of the pulmonary arteries confirmed aneurysmal dilation of the main pulmonary artery and the left pulmonary artery (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eC).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe patient underwent median sternotomy for open-heart surgery. Interestingly, intraoperative exploration revealed that the lesion was not merely a supravalvular pulmonary membrane. Upon direct inspection, we found that the pulmonary valve was tricuspid with markedly thickened leaflets (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA), and the commissures were fused, resulting in severe pulmonary valve stenosis. Uniquely, a supravalvular membrane fused with one of the pulmonary valve leaflets, forming a pouch-like configuration (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB), which restricted leaflet mobility and collectively contributed to the severe obstruction. The fused commissures were incised to enlarge the valve orifice. Following successful weaning from cardiopulmonary bypass and resumption of cardiac activity, intraoperative transesophageal echocardiography demonstrated a significant decrease in pulmonary valve flow velocity compared to the preoperative measurement. The patient was subsequently transferred to the intensive care unit for one day. He had an uneventful recovery and was discharged 7 days after the operation. At the one-month outpatient follow-up, the patient reported complete resolution of previous exertional chest tightness and significant improvement in exercise tolerance. PWD measurement showed a peak systolic flow velocity across the pulmonary valve of 3.9 m/s, corresponding to an estimated peak systolic gradient of approximately 60 mmHg.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eSPS is a rare anomaly that can occur at any level in the pulmonary artery\u0026mdash;from the main trunk to branches. Acquired SPS typically develops following surgical procedures involving the main pulmonary artery, while congenital SPS is commonly associated with syndromes such as congenital rubella, Noonan, and Williams syndromes(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Isolated congenital SPS represents the rarest form of pulmonary stenosis(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e). A study by Yuan et al(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). reported that only 4 out of 333 SPS cases (1.2%) were isolated congenital SPS. Similarly, Kumar et al(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). documented encountering merely 4 cases (0.08%) of isolated congenital SPS among 4,231 congenital cardiac surgeries performed.\u003c/p\u003e \u003cp\u003eThe defining morphological feature of isolated congenital SPS is a hypertrophied, stenotic tissue ring located at the sinotubular junction of the main pulmonary artery. In most cases, the pulmonary valve leaflets will exhibit secondary thickening due to persistent high-velocity jet flow impingement. This condition is frequently misdiagnosed as pulmonary valve stenosis on TTE, with definitive diagnosis typically requiring cardiac angiography. In the present case, preoperative TTE identified only a discrete supravalvular pulmonary membrane, failing to detect the unique malformation in which this membrane was fused with one of the pulmonary valve leaflets, thereby forming a pouch-like structure. To the best of our knowledge, this specific anatomical variant has not been previously documented in the medical literature.\u003c/p\u003e \u003cp\u003eSurgical intervention is the primary treatment for SPS when patients become symptomatic or present with severe stenosis. For the commonly encountered annular membrane-induced SPS, membrane resection is the standard approach. For instance, Gourav et al(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). successfully relieved supravalvular pulmonary stenosis in a 1-year-old infant by complete excision of the membrane. Alternatively, Bacha et al(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). proposed a technique involving resection of the stenotic ring and reconstruction of the sinotubular junction using autologous tissues. They reported zero early or mid-term mortality in eight SPS cases (four of which were isolated SPS) repaired with this method, with no reinterventions required during a 22-month follow-up period(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e). Furthermore, the study by Dogan et al(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). demonstrated that repair of isolated SPS using an oval pericardial or Dacron patch also yields excellent clinical outcomes. Interestingly, Mukawa et al(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). also achieved favorable results by remodeling the pulmonary root using a modified Yacoub technique in an adult patient with symptomatic SPS following pulmonary artery banding performed in childhood. Given the rarity of isolated congenital SPS, long-term follow-up data remain scarce, making it difficult to draw definitive conclusions regarding reintervention rates. In the present case, the unique fusion of the membrane with a pulmonary valve leaflet, forming a pouch-like structure, precluded conventional membrane resection. Therefore, we performed simple commissurotomy at the fused pulmonary valve commissure to relieve the valvular stenosis. The patient remained asymptomatic during follow-up evaluations. Although the postoperative transvalvular gradient remains at 60 mmHg, given the preoperative gradient as high as 170 mmHg and the significant leaflet thickening with commissural fusion, simple commissurotomy has substantially reduced the hemodynamic burden, achieving complete symptom resolution and improved quality of life. The residual gradient may be attributed to leaflet fibrosis, thickening, and secondary changes, which limit complete leaflet expansion and mobility. In such cases, more aggressive surgical approaches\u0026mdash;such as pulmonary valve replacement or complex leaflet reconstruction techniques\u0026mdash;could entail greater operative risks. Moreover, preserving the patient's native valve structure is advantageous for long-term valve function and simplifies anticoagulation management, particularly in this young patient.\u003c/p\u003e \u003cp\u003eThis case highlights that for complex anatomical variants involving fusion between a supravalvular membrane and a valve leaflet, preoperative imaging may not fully reveal the three-dimensional morphology and the extent of fusion. Intraoperative exploration therefore becomes crucial in determining the definitive surgical strategy. In the future, incorporating three-dimensional transesophageal echocardiography or cardiac magnetic resonance imaging may facilitate more precise preoperative planning. Should symptoms recur or progress, further surgical(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e) or interventional options(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) could be considered.\u003c/p\u003e \u003cp\u003eIn summary, this case demonstrates a rare anatomical variant of isolated congenital SPS, the treatment of which requires individualized surgical planning. Despite the presence of a residual gradient postoperatively, the symptomatic relief and hemodynamic improvement achieved through commissurotomy have led to an acceptable early clinical outcome.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eSPS, supravalvular pulmonary stenosis\u003c/p\u003e\n\u003cp\u003eTTE, transthoracic echocardiography\u003c/p\u003e\n\u003cp\u003ePWD, pulsed-wave Doppler\u003c/p\u003e\n\u003cp\u003eCTA, computed tomography angiography\u003c/p\u003e\n\u003cp\u003eSPM, supravalvular pulmonary membrane\u003c/p\u003e\n\u003cp\u003ePV, pulmonary valve\u003c/p\u003e\n\u003cp\u003eRVOT, right ventricular outflow tract\u003c/p\u003e\n\u003cp\u003eMPA, main pulmonary artery\u003c/p\u003e\n\u003cp\u003eLPA, left pulmonary artery\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was reviewed and approved by the Ethics Committee of the First Affiliated Hospital, School of Medicine, Zhejiang University. The patient provided her written informed consent to participate in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for the publication of this case report.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data and materials used during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no financial or non-financial competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eXC and ALH wrote the original manuscript and prepared all figures; XJZ and RYL reviewed the manuscript; RYL performed the surgery and administrated the study. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eGourav KP, Guha Niyogi S, Negi S, Amburu V. Supravalvular pulmonary stenosis caused by a membrane in the main pulmonary artery. Eur Heart J Cardiovasc Imaging. 2020;21(10):1173.\u003c/li\u003e\n \u003cli\u003eKumar V, Mahajan S, Jaswal V, Thingnam SKS. Surgical outcome of isolated congenital supravalvular pulmonary stenosis: a case series. Eur Heart J Case Rep. 2019;3(2).\u003c/li\u003e\n \u003cli\u003eMilo S, Fiegel A, Shem-Tov A, Neufeld HN, Goor DA. Hour-glass deformity of the pulmonary valve: a third type of pulmonary valve stenosis. Br Heart J. 1988;60(2):128-33.\u003c/li\u003e\n \u003cli\u003eYuan SM. Supravalvular pulmonary stenosis: Congenital versus acquired. Acta Medica Mediterranea. 2017;33:849-56.\u003c/li\u003e\n \u003cli\u003eBacha EA, Kalimi R, Starr JP, Quinones J, Koenig P. Autologous repair of supravalvar pulmonic stenosis. Ann Thorac Surg. 2004;77(2):734-6.\u003c/li\u003e\n \u003cli\u003eDogan OF, Demircin M, Ozkutlu S, Pasaoglu I. Surgical management of infants with isolated supravalvular pulmonary stenosis: case reports. Heart Surg Forum. 2006;9(4):E668-74; discussion E73-4.\u003c/li\u003e\n \u003cli\u003eMukawa K, Iba Y, Kawaharada N. Pulmonary root remodeling procedure for symptomatic supravalvular pulmonary stenosis in an adult patient who underwent pulmonary artery banding: a case report. BMC Cardiovasc Disord. 2024;24(1):619.\u003c/li\u003e\n \u003cli\u003eCagdas M, Cinar T, Karabag Y, Rencuzogullari I. Successful treatment of supravalvular pulmonary membranous stenosis with percutaneous balloon valvuloplasty. Acta Cardiol. 2020;75(5):473-4.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"journal-of-cardiothoracic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jcts","sideBox":"Learn more about [Journal of Cardiothoracic Surgery](http://cardiothoracicsurgery.biomedcentral.com)","snPcode":"13019","submissionUrl":"https://submission.nature.com/new-submission/13019/3","title":"Journal of Cardiothoracic Surgery","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"supravalvular pulmonary stenosis, commissure fusion, supravalvular membrane","lastPublishedDoi":"10.21203/rs.3.rs-8345329/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8345329/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Isolated congenital supravalvular pulmonary stenosis is an exceedingly rare cardiac anomaly, typically characterized by a discrete membrane above the valve obstructing the main pulmonary artery. We present a previously unreported anatomical variation in which this membrane fused with one of the pulmonary valve leaflets, forming a distinct pouch-like configuration.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase Presentation\u003c/strong\u003e: A 44-year-old male presented with progressive exertional dyspnea. Preoperative echocardiography identified severe pulmonary stenosis and an obstructing supravalvular membrane, with a peak transvalvular gradient of 170 mmHg. Intraoperative exploration revealed that the pulmonary valve is trileaflet, with visibly thickened and fused commissures, causing severe pulmonary valve stenosis. Uniquely, the supravalvular pulmonary membrane fused with one leaflet forming a pouch-like configuration. Surgical separation of the fused commissures was performed, which successfully relieved the obstruction. The patient recovered well and reported complete symptom resolution at one-month follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: This case presents a unique anatomical variant of isolated congenital supravalvular pulmonary stenosis, characterized by fusion between the abnormal supravalvular membrane and one valve leaflet. The surgical approach adopted achieved acceptable results and substantially improved the patient's clinical condition.\u003c/p\u003e","manuscriptTitle":"Pulmonary Valve and Supravalvular Membrane Fusion Forming a Pouch-like Configuration: A Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-09 07:27:38","doi":"10.21203/rs.3.rs-8345329/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-05T07:36:23+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-09T17:12:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"112541138030112570819667374088685014957","date":"2026-02-07T09:28:21+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-06T07:12:52+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"278721909785325674926897655941141576293","date":"2026-02-05T17:24:10+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-05T14:49:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"139150445613781716782568995216451885826","date":"2026-02-05T14:02:04+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-04T11:28:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"316039258365197961637622779765927491235","date":"2026-02-04T10:11:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"185580363099074074327124723362107352807","date":"2026-02-03T18:31:50+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-03T17:11:22+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-22T05:37:13+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-22T05:35:16+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Cardiothoracic Surgery","date":"2025-12-12T11:17:24+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-cardiothoracic-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jcts","sideBox":"Learn more about [Journal of Cardiothoracic Surgery](http://cardiothoracicsurgery.biomedcentral.com)","snPcode":"13019","submissionUrl":"https://submission.nature.com/new-submission/13019/3","title":"Journal of Cardiothoracic Surgery","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"9a2e032f-0e7e-4d42-b79d-9614e0312c61","owner":[],"postedDate":"February 9th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-18T08:23:30+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-09 07:27:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8345329","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8345329","identity":"rs-8345329","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}