Sinus Node and Right Coronary Artery Aneurysms With Atrial Fistula: A Case Report and Literature Review

Sinus Node and Right Coronary Artery Aneurysms With Atrial Fistula: A Case Report and Literature Review | 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 Sinus Node and Right Coronary Artery Aneurysms With Atrial Fistula: A Case Report and Literature Review Tue Minh Vo, Dung Duc Nguyen, Hung Xuan Nguyen, Phuoc Dang Nguyen, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7095450/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: Sinus node artery aneurysms are exceptionally rare, especially when combined with a right coronary artery aneurysm and a fistulous tract draining into the right atrium. Only two adult cases with this triad have been reported. We present the youngest known adult with this anomaly, aiming to emphasize the value of early imaging-based diagnosis and individualized surgical management. Case presentation: A 23-year-old male presented with a one-year history of exertional dyspnea. Physical examination and laboratory tests were normal. Transthoracic echocardiography suggested a coronary fistula with abnormal continuous flow into the right atrium. Contrast-enhanced computed tomography revealed a 13 mm sinus node artery aneurysm arising from a proximally aneurysmal right coronary artery (12 mm) and draining via a 9 mm fistula into the right atrium. The right atrium was markedly dilated. Surgical correction was performed under cardiopulmonary bypass. The intra-atrial fistulous orifice was closed using pledgeted sutures and the extracardiac tract was ligated. The sinus node artery was preserved, and no reconstruction was performed on the right coronary artery. The patient recovered without complications and was discharged on postoperative day seven with preserved sinus rhythm. Conclusion: This case highlights an extremely rare coronary artery anomaly in a young adult. Large fistulas, even when associated with moderate aneurysms, may cause significant volume overload and warrant early intervention. Our case reinforces the importance of multimodal imaging and timely surgery to prevent progression and preserve cardiac function. Sinus node artery aneurysm right coronary artery aneurysm coronary fistula case report literature review Figures Figure 1 Figure 2 Background Sinus node artery (SNA) aneurysms are exceptionally rare, and their coexistence with coronary artery fistulas (CAFs) is even more uncommon. Coronary artery aneurysms occur in less than 1% of the population [1], while CAFs are seen in 0.1–0.2% of cases, often draining into the right atrium (RA) [2]. The combination of an SNA aneurysm, right coronary artery (RCA) aneurysm, and a fistula into the RA represents a rare coronary triad, with only two adult cases previously reported [1],[3]. These lesions can lead to coronary steal, arrhythmias, and right heart dilation, particularly when the fistula is large. Because there are no established guidelines, treatment decisions are based on symptoms, aneurysm size, and shunt volume. Multimodality imaging, especially three-dimensional computed tomography angiography, is critical for diagnosis and surgical planning [1],[4],[5]. We report the youngest adult case of this triad and provide a literature review to support clinical decision-making. Case presentation A 23-year-old male presented with a one-year history of exertional dyspnea. He denied chest pain, palpitations, or syncope. Physical examination and laboratory investigations were unremarkable. Transthoracic echocardiography revealed continuous abnormal flow into the RA, suggesting a CAF, and an aneurysmal RCA. Color Doppler demonstrated a significant shunt with an estimated fistulous orifice of 5 mm. Right ventricular function and pulmonary artery pressures were normal. The patient was a nonsmoker and reported no history of cardiovascular or pulmonary disease, congenital anomalies, trauma, or systemic inflammation. A 512-slice contrast-enhanced coronary computed tomography scan using volume rendering, multiplanar reconstruction, and maximum intensity projection (Figure 1, Figure 2) showed an aneurysmal RCA ostium (10 mm) and proximal RCA (11 mm). The SNA originated from the RCA and showed a 13 mm aneurysm. It coursed posteriorly and drained into the lateral wall of the RA via a 9 mm fistula, which is classified as a large fistula [2]. The RA was markedly dilated (63 mm), and no coronary calcification or atherosclerosis was observed. Due to the anatomical complexity and large left-to-right shunt, surgical correction was performed under cardiopulmonary bypass. A right atriotomy exposed a 4 mm fistulous orifice at the posterolateral RA wall, which was closed with pledgeted sutures. External dissection confirmed and ligated the extracardiac segment. The SNA was preserved without proximal occlusion or reconstruction. The RCA aneurysm was left untouched, considering its moderate size and limited myocardial risk. The patient recovered uneventfully, maintained sinus rhythm, and was discharged on postoperative day seven without complications Discussion This case highlights a rare but surgically correctable triad involving an aneurysmal SNA, RCA, and CAF draining into the RA. While isolated SNA aneurysms or CAFs have been described, their coexistence—especially with an RCA aneurysm—is extremely uncommon. Only two adult cases with this specific constellation have been reported in the literature [1],[3]. We report the case of the youngest adult with this rare coronary triad who was successfully managed with surgery. To contextualize these finding, we reviewed nine published cases of SNA aneurysms—with or without fistulas—grouped by lesion type, as shown in Table 1 . Most patients reviewed had nonspecific symptoms such as exertional dyspnea, palpitations, or fatigue. Notably, Kim et al. [6] reported profound signs and symptoms of superior vena cava compression from a large aneurysm. Our patient’s isolated dyspnea reflects this pattern and highlights the subtlety of the clinical findings. Most published cases are female (from adolescence to elderly adulthood). Our patient is the youngest male adult reported with this triad. Although the SNA aneurysm in our case was smaller than that in most reported cases (13 mm vs. up to 150 mm), the large fistula (9 mm) resulted in significant RA dilation and findings suggestive of coronary steal syndrome, including exertional dyspnea and an RCA – RA shunt visualized via echocardiography. This highlights that fistula flow, not aneurysm size alone, drives clinical, and hemodynamic impact and warrants early diagnosis. In our review, the SNA most frequently originated from the RCA but less commonly from the left main coronary artery[4],[7]. The RA was the predominant drainage site of associated fistulas, with only one case involving the left atrium. SNA aneurysms with CAFs have been linked to adverse cardiac sequelae, including myocardial ischemia, endarteritis, progressive chamber dilatation, and ventricular dysfunction [2]. The hemodynamic burden of the triad—particularly large aneurysms and significant shunt volumes—warrants early identification. Our case demonstrated this triad with clear anatomy via echocardiography and computed tomography angiography. Three-dimensional computed tomography reconstruction was particularly valuable in defining the vascular course and planning intervention, as also demonstrated in previous studies [1],[3],[4],[5]. A useful demonstration of hemodynamic assessment was provided by Shibagaki et al. [1] , who performed cardiac catheterization and reported a pulmonary-to-systemic flow ratio (Qp/Qs) of 1.6, indicating a significant left-to-right shunt. This approach highlights the value of invasive hemodynamic evaluation in quantifying shunt burden and guiding clinical decision-making. Currently, there are no standardized guidelines for managing SNA aneurysms or related fistulas. Treatment depends on symptoms, aneurysm size, fistula flow, and associated cardiac dysfunction. Spontaneous closure is frequently observed in small fistulas, supporting the use of conservative strategies in asymptomatic or stable cases [2]. However, younger individuals may be at risk for progressive enlargement of moderate-to-large CAFs [2]. Given the link between chronic shunt flow and coronary dilation, early closure of medium-sized fistulas may be warranted to prevent progression, and reduce the risk of myocardial infarction in larger lesions [2]. In our case, the patient experienced exertional dyspnea, a substantial left-to-right shunt caused by a 9-mm fistula, and marked RA enlargement along with SNA and RCA aneurysms, clearly indicating intervention. According to Al-Hijji et al. [2], our case fits the category of a large CAF originating from the distal coronary bed, accompanied by proximal coronary artery ectasia ≥10 mm, justified surgical closure and bypass. Among the reviewed patients, surgical intervention was favored in all patients, with 1 patient refusing surgery [3]. The goals of coronary artery aneurysm with CAF repair include aneurysm resection, coronary reconstruction, and fistula closure. Procedures involving SNA aneurysms are more complex because of the risk of sinus node dysfunction and atrial arrhythmias. One study reported dysfunction in 80% of patients after SNA occlusion, with 20% requiring temporary pacing and 6.7% requiring permanent pacing [8]. In Shibagaki’s case [1], temporary SNA occlusion caused transient P wave loss and bradycardia (HR 60 bpm) without sinoatrial arrest; the sinus rhythm returned two days after ligation. Hiraoka [5] preserved the SNA by ligating only feeding arteries from the SNA and LCx. Chen [9] performed isolated fistula ligation. In the case of Huang [4], the aneurysm originated from the left main coronary artery and required ligation of both the left main and the proximal SNA, necessitating coronary bypass due to resulting myocardial ischemia. Our patient was notably young (23 years), with a 13-mm SNA aneurysm—moderate compared with previously reported sizes (50–150 mm, Table 1). Given its size, we elected not to perform aneurysm resection or reconstruction. To minimize the risk of sinus node dysfunction associated with SNA occlusion, we opted for a targeted surgical approach. The fistula was ligated externally at the posterolateral wall of the RA after direct intra-atrial closure of the fistulous orifice. This allowed us to preserve the integrity and perfusion of the SNA. Similarly, although the RCA exhibited aneurysmal dilation (11 mm), we did not pursue aggressive interventions such as reconstruction, arterial ligation or bypass grafting, considering the patient's young age and most importantly minimal myocardial territory at risk. We anticipate that complete exclusion of the left-to-right shunt, achieved through fistula closure, may promote favorable arterial remodeling in the future. Conclusion This case adds to the limited literature on SNA aneurysms with CAFs in young adults. It underscores the need for early recognition of subtle symptoms and the value of multimodal imaging in defining coronary anatomy. Prompt, individualized surgical intervention can achieve excellent outcomes while preserving sinus rhythm and cardiac function. Abbreviations CAF Coronary Artery Fistula RA Right Atrium RCA Right Coronary Artery SNA Sinus node artery Declarations Ethics approval and consent to participate This study did not require ethical approval, as per the policy of our institution regarding case reports and case series. Consent for publication Written informed consent was obtained from the patient for publication of anonymized clinical information and images. Availability of data and materials The datasets used or analyzed during the current study are available from the corresponding author upon reasonable request. Competing interests No funding was received for this study. Funding: No funding Authors' contributions TMV: Writing – original draft, literature review. VDAB: Conceptualization, supervision, literature review, critical revision of the manuscript. DDN, HXN, PDN: Surgical management and intraoperative documentation. NTTT: Data collection and figure preparation. CD, TT: English editing, manuscript review, and formatting. Acknowledgements The authors thank the Department of Radiology, Hue Central Hospital, for imaging support, and the patient for consenting to publication References Shibagaki K, Kainuma S, Kamiya H, Fujita T, Fukushima S. Minimally Invasive Repair of a Sinus Node Artery Aneurysm With a Fistula Into the Right Atrium. Ann Thorac Surg Short Rep. 2024;2(1):35-7. Al-Hijji M, El Sabbagh A, El Hajj S, AlKhouli M, El Sabawi B, Cabalka A, et al. Coronary Artery Fistulas: Indications, Techniques, Outcomes, and Complications of Transcatheter Fistula Closure. JACC Cardiovasc Interv. 2021;14(13):1393-406. Piskin F, Shahverenova A, Akilli R, Demir M, Aksungur E. An extremely rare coronary artery fistula extending from the sinoatrial nodal artery to the right atrium. Turk Gogus Kalp Damar Cerrahisi Derg. 2022;30(2):299-301. Huang J, Zeng K, Yang Y, Zhang Y, Wang J. Sinus node artery aneurysm arising from the left main coronary artery with a fistula into the right atrium. Gilmanov DS,. 2019;34(1):37-40. Hiraoka A, Kuinose M, Totsugawa T, Yoshitaka H. Giant coronary artery aneurysm arising from the sinus node artery with a fistula into the left atrium. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 2013;43(3):646-8. Kim SH, Jang IS, Ouck CD, Kim CW, Choi JY, Kim HJ, et al. Giant atherosclerotic aneurysm of the sinoatrial nodal artery. The Journal of thoracic and cardiovascular surgery. 1997;114(2):280-2. Kumari U, Rahman M, Jan MU, Ullah SR, Abbas F, Shirazi Z, et al. Giant Sinoatrial Nodal Artery Aneurysm with Fistula into the Right Atrium Treated by Partial Resection and Plication: A Case Report. J Tehran Heart Cent. 2023;18(2):142-5. Koren O, Antonelli D, Khamaise R, Ehrenberg S, Rozner E, Turgeman Y. Sinus Node Dysfunction due to Occlusion of the Sinus Node Artery during Percutaneous Coronary Intervention. J Interv Cardiol. 2021;2021:8810484. Chen SM, Cheng NJ, Chu PH, Ko YL, Chiang CW, Lee YS. Sinoatrial nodal artery aneurysm with right ventricular outflow tract compression: report of a case. Catheter Cardiovasc Interv. 2000;51(3):328-31. Kanemitsu N, Nakamura T, Okabe M, Tenpaku H, Wariishi S, Ohki A. Giant coronary artery aneurysm arising from sinus node artery. The Annals of thoracic surgery. 2001;72(4):1373-4. Table Table 1. Summary of reported cases involving sinus node artery aneurysms and/or coronary artery fistulas Author Age/Sex SNA Aneurysm Size Fistula Present Fistula Drains into Other Findings Management Group 1: Sinus Node Artery Aneurysm Without Fistula Kim (1997) [6] 61/F 150 mm No Superior vena cava compression Resection Kanemitsu (2001) [10] 74/F 50 mm No Off-pump resection of the aneurysm, preservation of SNA Group 2: Sinus Node Artery Aneurysm With Fistula Tue (2025) 23/M 13 mm Yes RA RCA aneurysm RA dilation Fistula ligation Closure fistula orifice from inside of RA Shibagaki (2024) [1] 29/F 15x17 mm Yes RA RCA aneurysm Minimally invasive ligation of SNA Piskin (2022) [3] 28/F Not stated Yes RA RCA aneurysm Medical treatment (refuse surgery) Chen (2000) [9] 16/M Not stated Yes RA Right ventricular outflow tract compression Fistula ligation Huang (2019) [4] 60/F 90×80 mm Yes RA LMCA origin Ligation of LMCA, SNA and CABG Kumari (2023) [7] 46/F 1 large pseudoaneurysm: 70.4 ×61.7 mm 3 small pseudoaneurysms:9,6 mm, 8,5 mm, 6,9 mm Yes RA LMCA origin Partial resection + plication of aneurysm Hiraoka (2013) [5] 76/F 70×50 mm Yes LA Dual feeders (SNA + LCx) - Ligation of feeding artery - Resection of the aneurysm - Closure of fistula entry with patch Abbreviations: CABG = coronary artery bypass grafting; LA = left atrium; LCx = left circumflex artery; LMCA = left main coronary artery; RA = right atrium; RCA = right coronary artery. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7095450","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":484306892,"identity":"e67a48f4-768f-4a41-af8c-50ec0b74a670","order_by":0,"name":"Tue Minh Vo","email":"","orcid":"","institution":"Hue Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tue","middleName":"Minh","lastName":"Vo","suffix":""},{"id":484306893,"identity":"fd8e141d-d43d-4f48-a187-1e5fbbce82e4","order_by":1,"name":"Dung Duc Nguyen","email":"","orcid":"","institution":"Hue Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Dung","middleName":"Duc","lastName":"Nguyen","suffix":""},{"id":484306894,"identity":"d2fd60d3-26f7-478c-895f-6d24b66abe05","order_by":2,"name":"Hung Xuan Nguyen","email":"","orcid":"","institution":"Hue Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hung","middleName":"Xuan","lastName":"Nguyen","suffix":""},{"id":484306896,"identity":"50363a93-a382-41fa-9fc0-f7c324fb1241","order_by":3,"name":"Phuoc Dang Nguyen","email":"","orcid":"","institution":"Hue Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Phuoc","middleName":"Dang","lastName":"Nguyen","suffix":""},{"id":484306899,"identity":"9fd62a6b-13e0-44c4-899f-9edeae75de64","order_by":4,"name":"Nhan Thanh Thai Tran","email":"","orcid":"","institution":"Hue Central Hospital","correspondingAuthor":false,"prefix":"","firstName":"Nhan","middleName":"Thanh Thai","lastName":"Tran","suffix":""},{"id":484306902,"identity":"b9558c92-f113-4552-83b3-a8fdaa83edab","order_by":5,"name":"Chau Dang","email":"","orcid":"","institution":"San Joaquin General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chau","middleName":"","lastName":"Dang","suffix":""},{"id":484306904,"identity":"ce31b49f-0219-48b8-a88e-02f32b6e8ebf","order_by":6,"name":"Tam Tran","email":"","orcid":"","institution":"Washington University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Tam","middleName":"","lastName":"Tran","suffix":""},{"id":484306906,"identity":"adb1a758-f3da-4c57-9add-12cae38ea7c6","order_by":7,"name":"Vinh Duc An Bui","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA40lEQVRIiWNgGAWjYBACAwbGBgkwi5mBjeEDkGZjJ0UL4wyQFmaCWhgYJKBsNmYeiF78wFwiufE2T41dnsFx3mOPbX5tk+djZmD88DEHtxbLGYnN1jzHkosNDvOlG+f23TZsY2Zglpy5DY/DbiS2SfM2MCfObOYxk87tuc0I1MLGzEtYSz1Ei2XPbXtitRxO7GcGamH4cTuRoBbLnofNlnOOHQdrkextuJ3cxszYjNcv5uzpD2+8qalObOM/Yybx489t2/ntzQc/fMSjBRUwtoHJBmLVg8AfUhSPglEwCkbBSAEA16NKGx0JFOMAAAAASUVORK5CYII=","orcid":"","institution":"Hue Central Hospital","correspondingAuthor":true,"prefix":"","firstName":"Vinh","middleName":"Duc An","lastName":"Bui","suffix":""}],"badges":[],"createdAt":"2025-07-10 18:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7095450/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7095450/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":86670994,"identity":"15605157-6034-4c62-9084-9e6c42aba327","added_by":"auto","created_at":"2025-07-14 11:34:47","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":166852,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThree-dimensional volume-rendered CT angiography showing aneurysms of the sinus node artery and right coronary artery, with a fistulous connection to the right atrium\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA: Anatomical view displaying the sinus node artery (SNA) aneurysm, the origin of the right coronary artery (RCA), and the fistulous drainage site into the lateral wall of the right atrium (RA).\u003c/p\u003e\n\u003cp\u003eB: Rotated anterior view highlighting the aneurysmal SNA arising from the proximal RCA and its communication with the RA\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAbbreviations:\u003c/em\u003e CONUS = conus branch; CT=computed tomography; SNA = sinus node artery; RCA = right coronary artery; RA = right atrium.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7095450/v1/15b79b424460e17e0766ec71.png"},{"id":86670222,"identity":"2b17d05b-ba39-45ab-b1a0-04c4fc4bdc01","added_by":"auto","created_at":"2025-07-14 11:26:47","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":159917,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eContrast-enhanced CT with multiplanar reconstruction showing the course of the fistulous tract and its relation to cardiac structures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA: Axial view demonstrating a prominent fistulous tract (red arrow) originating from the SNA aneurysm and coursing toward the RA.\u003c/p\u003e\n\u003cp\u003eB: Four-chamber axial view illustrating the contrast jet (red arrow) entering the RA from the fistula, with evident chamber enlargement.\u003c/p\u003e\n\u003cp\u003eC: Sagittal reconstruction delineating the tortuous course of the fistula (red arrow) draining into the RA.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eAbbreviations: \u003c/em\u003eCT=computed tomography; RA = right atrium; LA = left atrium; RV = right ventricle; LV = left ventricle; RCA = right coronary artery; SNAa = sinus node artery aneurysm.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7095450/v1/c93368e5a718c7dc76b0130d.png"},{"id":99308733,"identity":"e21f9bb1-f322-450b-9873-d70ea3420b7c","added_by":"auto","created_at":"2025-12-31 16:09:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1037130,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7095450/v1/dd278d86-ce2f-425e-83a9-347f89b526a8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eSinus Node and Right Coronary Artery Aneurysms With Atrial Fistula: A Case Report and Literature Review\u003c/p\u003e","fulltext":[{"header":"Background","content":"\u003cp\u003eSinus node artery (SNA) aneurysms are exceptionally rare, and their coexistence with coronary artery fistulas (CAFs) is even more uncommon. Coronary artery aneurysms occur in less than 1% of the population [1], while CAFs are seen in 0.1–0.2% of cases, often draining into the right atrium (RA) [2]. The combination of an SNA aneurysm, right coronary artery (RCA) aneurysm, and a fistula into the RA represents a rare coronary triad, with only two adult cases previously reported [1],[3]. These lesions can lead to coronary steal, arrhythmias, and right heart dilation, particularly when the fistula is large. Because there are no established guidelines, treatment decisions are based on symptoms, aneurysm size, and shunt volume. Multimodality imaging, especially three-dimensional computed tomography angiography, is critical for diagnosis and surgical planning [1],[4],[5]. We report the youngest adult case of this triad and provide a literature review to support clinical decision-making.\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cp\u003eA 23-year-old male presented with a one-year history of exertional dyspnea. He denied chest pain, palpitations, or syncope. Physical examination and laboratory investigations were unremarkable. Transthoracic echocardiography revealed continuous abnormal flow into the RA, suggesting a CAF, and an aneurysmal RCA. Color Doppler demonstrated a significant shunt with an estimated fistulous orifice of 5 mm. Right ventricular function and pulmonary artery pressures were normal.\u003c/p\u003e\n\u003cp\u003eThe patient was a nonsmoker and reported no history of cardiovascular or pulmonary disease, congenital anomalies, trauma, or systemic inflammation. A 512-slice contrast-enhanced coronary computed tomography scan using volume rendering, multiplanar reconstruction, and maximum intensity projection \u003cstrong\u003e(Figure 1, Figure 2)\u003c/strong\u003e showed an aneurysmal RCA ostium (10 mm) and proximal RCA (11 mm). The SNA originated from the RCA and showed a 13 mm aneurysm. It coursed posteriorly and drained into the lateral wall of the RA via a 9 mm fistula, which is classified as a large fistula [2]. The RA was markedly dilated (63 mm), and no coronary calcification or atherosclerosis was observed.\u003c/p\u003e\n\u003cp\u003eDue to the anatomical complexity and large left-to-right shunt, surgical correction was performed under cardiopulmonary bypass. A right atriotomy exposed a 4 mm fistulous orifice at the posterolateral RA wall, which was closed with pledgeted sutures. External dissection confirmed and ligated the extracardiac segment. The SNA was preserved without proximal occlusion or reconstruction. The RCA aneurysm was left untouched, considering its moderate size and limited myocardial risk. The patient recovered uneventfully, maintained sinus rhythm, and was discharged on postoperative day seven without complications\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis case highlights a rare but surgically correctable triad involving an aneurysmal SNA, RCA, and CAF draining into the RA. While isolated SNA aneurysms or CAFs have been described, their coexistence—especially with an RCA aneurysm—is extremely uncommon. Only two adult cases with this specific constellation have been reported in the literature [1],[3]. We report the case of the youngest adult with this rare coronary triad who was successfully managed with surgery. To contextualize these finding, we reviewed nine published cases of SNA aneurysms—with or without fistulas—grouped by lesion type, as shown in \u003cstrong\u003eTable 1\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003eMost patients reviewed had nonspecific symptoms such as exertional dyspnea, palpitations, or fatigue. Notably, Kim et al. [6] reported profound signs and symptoms of superior vena cava compression from a large aneurysm. Our patient’s isolated dyspnea reflects this pattern and highlights the subtlety of the clinical findings. Most published cases are female (from adolescence to elderly adulthood). Our patient is the youngest male adult reported with this triad.\u003c/p\u003e\n\u003cp\u003eAlthough the SNA aneurysm in our case was smaller than that in most reported cases (13 mm vs. up to 150 mm), the large fistula (9 mm) resulted in significant RA dilation and findings suggestive of coronary steal syndrome, including exertional dyspnea and an RCA – RA shunt visualized via echocardiography. This highlights that fistula flow, not aneurysm size alone, drives clinical, and hemodynamic impact and warrants early diagnosis. In our review, the SNA most frequently originated from the RCA but less commonly from the left main coronary artery[4],[7]. The RA was the predominant drainage site of associated fistulas, with only one case involving the left atrium.\u003c/p\u003e\n\u003cp\u003eSNA aneurysms with CAFs have been linked to adverse cardiac sequelae, including myocardial ischemia, endarteritis, progressive chamber dilatation, and ventricular dysfunction [2]. The hemodynamic burden of the triad—particularly large aneurysms and significant shunt volumes—warrants early identification. Our case demonstrated this triad with clear anatomy via echocardiography and computed tomography angiography. Three-dimensional computed tomography reconstruction was particularly valuable in defining the vascular course and planning intervention, as also demonstrated in previous studies [1],[3],[4],[5]. A useful demonstration of hemodynamic assessment was provided by Shibagaki et al. [1] , who performed cardiac catheterization and reported a pulmonary-to-systemic flow ratio (Qp/Qs) of 1.6, indicating a significant left-to-right shunt. This approach highlights the value of invasive hemodynamic evaluation in quantifying shunt burden and guiding clinical decision-making.\u003c/p\u003e\n\u003cp\u003eCurrently, there are no standardized guidelines for managing SNA aneurysms or related fistulas. Treatment depends on symptoms, aneurysm size, fistula flow, and associated cardiac dysfunction. Spontaneous closure is frequently observed in small fistulas, supporting the use of conservative strategies in asymptomatic or stable cases [2]. However, younger individuals may be at risk for progressive enlargement of moderate-to-large CAFs [2]. Given the link between chronic shunt flow and coronary dilation, early closure of medium-sized fistulas may be warranted to prevent progression, and reduce the risk of myocardial infarction in larger lesions [2]. In our case, the patient experienced exertional dyspnea, a substantial left-to-right shunt caused by a 9-mm fistula, and marked RA enlargement along with SNA and RCA aneurysms, clearly indicating intervention.\u003c/p\u003e\n\u003cp\u003eAccording to Al-Hijji et al. [2], our case fits the category of a large CAF originating from the distal coronary bed, accompanied by proximal coronary artery ectasia ≥10 mm, justified surgical closure and bypass. Among the reviewed patients, surgical intervention was favored in all patients, with 1 patient refusing surgery [3].\u003c/p\u003e\n\u003cp\u003eThe goals of coronary artery aneurysm with CAF repair include aneurysm resection, coronary reconstruction, and fistula closure. Procedures involving SNA aneurysms are more complex because of the risk of sinus node dysfunction and atrial arrhythmias. One study reported dysfunction in 80% of patients after SNA occlusion, with 20% requiring temporary pacing and 6.7% requiring permanent pacing [8]. In Shibagaki’s case [1], temporary SNA occlusion caused transient P wave loss and bradycardia (HR 60 bpm) without sinoatrial arrest; the sinus rhythm returned two days after ligation. Hiraoka [5] preserved the SNA by ligating only feeding arteries from the SNA and LCx. Chen [9] performed isolated fistula ligation. In the case of Huang [4], the aneurysm originated from the left main coronary artery and required ligation of both the left main and the proximal SNA, necessitating coronary bypass due to resulting myocardial ischemia.\u003c/p\u003e\n\u003cp\u003eOur patient was notably young (23 years), with a 13-mm SNA aneurysm—moderate compared with previously reported sizes (50–150 mm, Table 1). Given its size, we elected not to perform aneurysm resection or reconstruction. To minimize the risk of sinus node dysfunction associated with SNA occlusion, we opted for a targeted surgical approach. The fistula was ligated externally at the posterolateral wall of the RA after direct intra-atrial closure of the fistulous orifice. This allowed us to preserve the integrity and perfusion of the SNA.\u003c/p\u003e\n\u003cp\u003eSimilarly, although the RCA exhibited aneurysmal dilation (11 mm), we did not pursue aggressive interventions such as reconstruction, arterial ligation or bypass grafting, considering the patient's young age and most importantly minimal myocardial territory at risk. We anticipate that complete exclusion of the left-to-right shunt, achieved through fistula closure, may promote favorable arterial remodeling in the future.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis case adds to the limited literature on SNA aneurysms with CAFs in young adults. It underscores the need for early recognition of subtle symptoms and the value of multimodal imaging in defining coronary anatomy. Prompt, individualized surgical intervention can achieve excellent outcomes while preserving sinus rhythm and cardiac function.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eCAF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eCoronary Artery Fistula\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eRA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eRight Atrium\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eRCA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eRight Coronary Artery\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eSNA\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eSinus node artery\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Declarations","content":"\u003ch4\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eThis study did not require ethical approval, as per the policy of our institution regarding case reports and case series.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for publication of anonymized clinical information and images.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eThe datasets used or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eNo funding was received for this study.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eNo funding\u003c/h4\u003e\n\u003ch4\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eTMV: Writing – original draft, literature review. VDAB: Conceptualization, supervision, literature review, critical revision of the manuscript. DDN, HXN, PDN: Surgical management and intraoperative documentation. NTTT: Data collection and figure preparation. CD, TT: English editing, manuscript review, and formatting.\u003c/p\u003e\n\u003ch4\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/h4\u003e\n\u003cp\u003eThe authors thank the Department of Radiology, Hue Central Hospital, for imaging support, and the patient for consenting to publication\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eShibagaki K, Kainuma S, Kamiya H, Fujita T, Fukushima S. Minimally Invasive Repair of a Sinus Node Artery Aneurysm With a Fistula Into the Right Atrium. Ann Thorac Surg Short Rep. 2024;2(1):35-7.\u003c/li\u003e\n\u003cli\u003eAl-Hijji M, El Sabbagh A, El Hajj S, AlKhouli M, El Sabawi B, Cabalka A, et al. Coronary Artery Fistulas: Indications, Techniques, Outcomes, and Complications of Transcatheter Fistula Closure. JACC Cardiovasc Interv. 2021;14(13):1393-406.\u003c/li\u003e\n\u003cli\u003ePiskin F, Shahverenova A, Akilli R, Demir M, Aksungur E. An extremely rare coronary artery fistula extending from the sinoatrial nodal artery to the right atrium. Turk Gogus Kalp Damar Cerrahisi Derg. 2022;30(2):299-301.\u003c/li\u003e\n\u003cli\u003eHuang J, Zeng K, Yang Y, Zhang Y, Wang J. Sinus node artery aneurysm arising from the left main coronary artery with a fistula into the right atrium. Gilmanov DS,. 2019;34(1):37-40.\u003c/li\u003e\n\u003cli\u003eHiraoka A, Kuinose M, Totsugawa T, Yoshitaka H. Giant coronary artery aneurysm arising from the sinus node artery with a fistula into the left atrium. European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. 2013;43(3):646-8.\u003c/li\u003e\n\u003cli\u003eKim SH, Jang IS, Ouck CD, Kim CW, Choi JY, Kim HJ, et al. Giant atherosclerotic aneurysm of the sinoatrial nodal artery. The Journal of thoracic and cardiovascular surgery. 1997;114(2):280-2.\u003c/li\u003e\n\u003cli\u003eKumari U, Rahman M, Jan MU, Ullah SR, Abbas F, Shirazi Z, et al. Giant Sinoatrial Nodal Artery Aneurysm with Fistula into the Right Atrium Treated by Partial Resection and Plication: A Case Report. J Tehran Heart Cent. 2023;18(2):142-5.\u003c/li\u003e\n\u003cli\u003eKoren O, Antonelli D, Khamaise R, Ehrenberg S, Rozner E, Turgeman Y. Sinus Node Dysfunction due to Occlusion of the Sinus Node Artery during Percutaneous Coronary Intervention. J Interv Cardiol. 2021;2021:8810484.\u003c/li\u003e\n\u003cli\u003eChen SM, Cheng NJ, Chu PH, Ko YL, Chiang CW, Lee YS. Sinoatrial nodal artery aneurysm with right ventricular outflow tract compression: report of a case. Catheter Cardiovasc Interv. 2000;51(3):328-31.\u003c/li\u003e\n\u003cli\u003eKanemitsu N, Nakamura T, Okabe M, Tenpaku H, Wariishi S, Ohki A. Giant coronary artery aneurysm arising from sinus node artery. The Annals of thoracic surgery. 2001;72(4):1373-4.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003ch4\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e \u003cstrong\u003eSummary of reported cases involving sinus node artery aneurysms and/or coronary artery fistulas\u003c/strong\u003e\u003c/h4\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAuthor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge/Sex\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSNA Aneurysm\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003eSize\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFistula Present\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFistula Drains into\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eOther Findings\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eManagement\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" style=\"width: 623px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 1: Sinus Node Artery Aneurysm Without Fistula\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eKim (1997) [6]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e61/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e150 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eSuperior vena cava compression\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eResection\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eKanemitsu (2001) [10]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e74/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e50 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eOff-pump resection of the aneurysm, preservation of SNA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"7\" valign=\"top\" style=\"width: 623px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGroup 2: Sinus Node Artery Aneurysm With Fistula\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eTue\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;(2025)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e23/M\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e13 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eRA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eRCA aneurysm\u003cbr\u003e\u0026nbsp;RA dilation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eFistula ligation\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;Closure fistula orifice from inside of RA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eShibagaki (2024) [1]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e29/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e15x17 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eRA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eRCA aneurysm\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMinimally invasive ligation of SNA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003ePiskin (2022) [3]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e28/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eNot stated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eRA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eRCA aneurysm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eMedical treatment\u003c/p\u003e\n \u003cp\u003e(refuse surgery)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eChen (2000) [9]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e16/M\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eNot stated\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eRA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eRight ventricular outflow tract compression\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eFistula ligation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eHuang (2019) [4]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e60/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e90\u0026times;80 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eRA\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eLMCA origin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eLigation of LMCA, SNA and CABG\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eKumari (2023) [7]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e46/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e1 large pseudoaneurysm: 70.4 \u0026times;61.7 mm\u003c/p\u003e\n \u003cp\u003e3 small pseudoaneurysms:9,6 mm, 8,5 mm, 6,9 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eRA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eLMCA origin\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003ePartial resection + plication of aneurysm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003eHiraoka (2013) [5]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 48px;\"\u003e\n \u003cp\u003e76/F\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e70\u0026times;50 mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 66px;\"\u003e\n \u003cp\u003eLA\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp\u003eDual feeders (SNA + LCx)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e- Ligation of feeding artery\u003c/p\u003e\n \u003cp\u003e- Resection of the aneurysm\u003c/p\u003e\n \u003cp\u003e- Closure of fistula entry with patch\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003eAbbreviations:\u003c/em\u003e CABG = coronary artery bypass grafting; LA = left atrium; LCx = left circumflex artery; LMCA = left main coronary artery; RA = right atrium; RCA = right coronary artery.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Sinus node artery aneurysm, right coronary artery aneurysm, coronary fistula, case report, literature review","lastPublishedDoi":"10.21203/rs.3.rs-7095450/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7095450/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground:\u003c/b\u003e\u003c/p\u003e\u003cp\u003eSinus node artery aneurysms are exceptionally rare, especially when combined with a right coronary artery aneurysm and a fistulous tract draining into the right atrium. Only two adult cases with this triad have been reported. We present the youngest known adult with this anomaly, aiming to emphasize the value of early imaging-based diagnosis and individualized surgical management.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCase presentation:\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA 23-year-old male presented with a one-year history of exertional dyspnea. Physical examination and laboratory tests were normal. Transthoracic echocardiography suggested a coronary fistula with abnormal continuous flow into the right atrium. Contrast-enhanced computed tomography revealed a 13 mm sinus node artery aneurysm arising from a proximally aneurysmal right coronary artery (12 mm) and draining via a 9 mm fistula into the right atrium. The right atrium was markedly dilated. Surgical correction was performed under cardiopulmonary bypass. The intra-atrial fistulous orifice was closed using pledgeted sutures and the extracardiac tract was ligated. The sinus node artery was preserved, and no reconstruction was performed on the right coronary artery. The patient recovered without complications and was discharged on postoperative day seven with preserved sinus rhythm.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion:\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis case highlights an extremely rare coronary artery anomaly in a young adult. Large fistulas, even when associated with moderate aneurysms, may cause significant volume overload and warrant early intervention. Our case reinforces the importance of multimodal imaging and timely surgery to prevent progression and preserve cardiac function.\u003c/p\u003e","manuscriptTitle":"Sinus Node and Right Coronary Artery Aneurysms With Atrial Fistula: A Case Report and Literature Review","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-14 11:26:42","doi":"10.21203/rs.3.rs-7095450/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"63409682-74d3-406a-83e0-26fa32250035","owner":[],"postedDate":"July 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-23T06:40:00+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-14 11:26:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7095450","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7095450","identity":"rs-7095450","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}