Large Mitral Valve Infective Endocarditis Missed on Initial Transthoracic Echocardiography in a Patient With Severe Aortic Stenosis and Complex Multisystem Comorbidities

Large Mitral Valve Infective Endocarditis Missed on Initial Transthoracic Echocardiography in a Patient With Severe Aortic Stenosis and Complex Multisystem Comorbidities | 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 Large Mitral Valve Infective Endocarditis Missed on Initial Transthoracic Echocardiography in a Patient With Severe Aortic Stenosis and Complex Multisystem Comorbidities Mohamed Ahmed Abdelzaher Mohamed Ayoub This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9214515/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 Infective endocarditis is a life-threatening condition requiring early diagnosis and prompt management. Transthoracic echocardiography (TTE) is commonly used as an initial diagnostic tool; however, its sensitivity may be limited in patients with complex structural heart disease. We report a 57-year-old male with severe calcific aortic stenosis and multiple comorbidities who presented with persistent Staphylococcus aureus bacteremia. Initial TTE showed no evidence of vegetations despite high clinical suspicion. Due to ongoing clinical deterioration, transesophageal echocardiography (TEE), performed 20 days later, revealed large mitral valve vegetations measuring up to 22 × 12 mm, associated with progression to severe mitral regurgitation. This case highlights the limitations of TTE in high-risk patients and emphasizes the importance of early TEE, particularly in the presence of persistent bacteremia and clinical deterioration, to avoid delayed diagnosis and adverse outcomes. Cardiac & Cardiovascular Systems Infective endocarditis transesophageal echocardiography transthoracic echocardiography mitral valve vegetation aortic stenosis case report Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Infective endocarditis remains a serious condition associated with substantial morbidity and mortality, with in-hospital mortality rates reported to range between 15% and 30% despite advances in diagnostic imaging and antimicrobial therapy [ 1 , 2 ]. Early diagnosis is essential to prevent complications such as valvular destruction, systemic embolization, and heart failure. Echocardiography plays a central role in diagnosis. Transthoracic echocardiography (TTE) is typically used as a first-line modality; however, its sensitivity may be limited in patients with structural heart disease or extensive valvular calcification [ 5 ]. Transesophageal echocardiography (TEE) provides superior spatial resolution and higher sensitivity for detecting vegetations and complications [10]. Current guidelines recommend TEE when clinical suspicion remains high despite negative TTE findings [ 1 ]. Case Presentation A 57-year-old male with a complex medical history of hypertension, polycythemia vera complicated by Budd-Chiari syndrome (status post portocaval shunt), and severe anemia presented with progressive dyspnea and clinical features of acute decompensated heart failure. On admission, transthoracic echocardiography (TTE) demonstrated preserved left ventricular systolic function (LVEF 60–65%), severe concentric left ventricular hypertrophy, and a heavily calcified trileaflet aortic valve with severe aortic stenosis (peak/mean gradient 171/134 mmHg, aortic valve area ~ 0.8 cm²) [Figure 1 ]. Mild mitral regurgitation was noted, with no evidence of intracardiac masses or vegetations [Figure 2 ]. The patient was noted to have severe transfusion-dependent anemia, requiring multiple packed red blood cell transfusions with minimal clinical improvement. Peripheral blood smear revealed tear-drop cells, suggestive of underlying myelofibrosis secondary to polycythemia vera. Massive splenomegaly was also present. During hospitalization, blood cultures grew Staphylococcus aureus, and intravenous cefazolin therapy was initiated. Despite appropriate antimicrobial treatment, the patient remained clinically unstable with persistent bacteremia and symptoms, raising high clinical suspicion for infective endocarditis. Transesophageal echocardiography (TEE) was initially planned but deferred due to significant clinical deterioration, including severe respiratory distress requiring non-invasive ventilatory support. Over the subsequent days, the patient developed rapid clinical worsening, with progression of mitral regurgitation leading to recurrent pulmonary edema and severe orthopnea. A follow-up TEE performed approximately 20 days after the initial TTE revealed a large mobile vegetation measuring approximately 22 × 12 mm attached to the posterior mitral leaflet (P2) [Figure 3 ], along with an additional smaller mobile mass on the anterior leaflet. These findings were associated with severe eccentric mitral regurgitation, supported by systolic flow reversal in the pulmonary veins [Figure 4 ]. The patient’s condition continued to deteriorate with recurrent episodes of pulmonary edema. Surgical intervention was considered; however, it was deemed prohibitively high risk given his multiple comorbidities and clinical instability. He was subsequently referred to a tertiary cardiac center for further evaluation and advanced management. Discussion This case illustrates a clinically significant delay in the diagnosis of infective endocarditis in a high-risk patient with persistent Staphylococcus aureus bacteremia, complex structural heart disease, and systemic comorbidities. Despite a negative initial transthoracic echocardiography (TTE), clinical suspicion remained high due to persistent bacteremia, emphasizing the importance of integrating microbiological and clinical findings rather than relying solely on imaging [ 1 , 2 ]. Transthoracic echocardiography (TTE) has well-recognized limitations in detecting vegetations, with reported sensitivity ranging between 50% and 70%, particularly in patients with poor acoustic windows or heavily calcified valves [ 3 ]. In this case, severe calcific aortic stenosis likely impaired visualization and contributed to the failure to detect early vegetations. In contrast, transesophageal echocardiography (TEE) offers superior sensitivity exceeding 90% and remains the gold standard in cases with high clinical suspicion [ 3 ]. According to current ESC guidelines, persistent Staphylococcus aureus bacteremia constitutes a major diagnostic criterion and should prompt early transesophageal echocardiography even when initial transthoracic imaging is negative [ 4 ]. An important learning point from this case is the presence of persistent Staphylococcus aureus bacteremia, which is strongly associated with aggressive infective endocarditis and rapid valvular destruction [ 4 ]. Current evidence suggests that in such high-risk scenarios, early TEE should be strongly considered even in the presence of an initially negative TTE [ 5 ]. Additionally, this case demonstrates a significant progression in disease severity within a relatively short time interval. The development of large vegetations measuring up to 22 × 12 mm, along with progression to severe mitral regurgitation, raises the possibility of either rapid disease progression or initial under-detection. This finding reinforces the importance of early repeat imaging and timely escalation to TEE in high-risk patients. From a clinical perspective, the delay in performing TEE due to patient instability reflects a common real-world challenge. However, earlier utilization may have facilitated earlier diagnosis and potentially altered management decisions, including earlier surgical evaluation. Vegetation size is a critical prognostic factor in infective endocarditis. Vegetations larger than 10 mm are associated with an increased risk of embolic events and adverse outcomes [ 6 ]. In this patient, the large vegetation burden further supports the need for early recognition and consideration of surgical intervention in accordance with current guidelines. Overall, this case underscores the limitations of TTE in high-risk patients and highlights the necessity of early TEE when clinical suspicion remains high, particularly in the context of persistent bacteremia and complex structural heart disease [ 7 ]. Conclusion This case emphasizes that a negative transthoracic echocardiogram does not exclude infective endocarditis in high-risk patients. Early transesophageal echocardiography should be strongly considered in cases of persistent clinical suspicion, particularly in the presence of Staphylococcus aureus bacteremia and complex structural heart disease. Declarations Patient Consent Patient consent was obtained for publication of this case report and accompanying images. References Habib G, Lancellotti P, Antunes MJ, et al.2023 ESC Guidelines for the management of infective endocarditis. Eur Heart J. 2023;44(39):3948–4042. Baddour LM, Wilson WR, Bayer AS, et al. Infective endocarditis in adults: diagnosis, antimicrobial therapy, and management of complications. Circulation. 2015;132(15):1435–1486. Cahill TJ, Prendergast BD.Infective endocarditis. Lancet. 2016;387(10021):882–893. Dayer MJ, et al.Epidemiology and outcomes of infective endocarditis. J Am Coll Cardiol. 2022;79(10):1039–1056. Evangelista A, Gonzalez-Alujas MT.Echocardiography in infective endocarditis.Heart. 2016;102(7):543–550. Pettersson GB, et al.Surgical treatment of infective endocarditis: AATS guidelines.J Thorac Cardiovasc Surg. 2019;157(2):e1–e55. Holland TL, et al.Staphylococcus aureus bacteremia: diagnosis and management.Clin Infect Dis. 2014;59(2):e10–e52. Additional Declarations The authors declare no competing interests. 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-9214515","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":611525852,"identity":"2c43cb3c-2dea-4946-80b2-6c054fdcf938","order_by":0,"name":"Mohamed Ahmed Abdelzaher Mohamed Ayoub","email":"data:image/png;base64,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","orcid":"https://orcid.org/0009-0008-3258-9119","institution":"Rashid hospital","correspondingAuthor":true,"prefix":"","firstName":"Mohamed","middleName":"Ahmed Abdelzaher Mohamed","lastName":"Ayoub","suffix":""}],"badges":[],"createdAt":"2026-03-24 16:38:39","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":true,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9214515/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9214515/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":105461350,"identity":"51a33452-dc5b-4e77-8477-2160e22cc4c3","added_by":"auto","created_at":"2026-03-26 10:04:40","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":397219,"visible":true,"origin":"","legend":"\u003cp\u003eTransthoracic echocardiography demonstrating severe aortic stenosis with markedly reduced aortic valve area (AVA ≈ 0.8 cm²).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-9214515/v1/522857fce9ff5aa3e3ecfde1.png"},{"id":105461352,"identity":"1117715f-93ad-4977-986d-ecf115720504","added_by":"auto","created_at":"2026-03-26 10:04:41","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":392291,"visible":true,"origin":"","legend":"\u003cp\u003eInitial transthoracic echocardiography with arrows indicating the mitral valve leaflets. No definite vegetation was visualized on the initial examination.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-9214515/v1/5b44c6970ea92ab36383012b.png"},{"id":105727777,"identity":"dec32b2e-98b7-41a6-9f13-f123c8402d6c","added_by":"auto","created_at":"2026-03-30 11:03:32","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":234613,"visible":true,"origin":"","legend":"\u003cp\u003eTransesophageal echocardiography showing a large mobile vegetation attached to the posterior mitral leaflet measuring approximately 22 × 12 mm.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9214515/v1/d50dffe60aac78447da5987a.png"},{"id":105461353,"identity":"facff01d-0f39-44f7-a6c3-e19717bf4566","added_by":"auto","created_at":"2026-03-26 10:04:41","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":524909,"visible":true,"origin":"","legend":"\u003cp\u003eColor Doppler imaging demonstrating severe mitral regurgitation with an eccentric regurgitant jet.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-9214515/v1/6afe7393ee33a75f218a0786.png"},{"id":105730373,"identity":"769810f6-9b91-45e5-afa0-3f96a9e751cf","added_by":"auto","created_at":"2026-03-30 11:24:07","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2237246,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9214515/v1/d8c2f606-1384-4489-ada8-ae2831dc2522.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eLarge Mitral Valve Infective Endocarditis Missed on Initial Transthoracic Echocardiography in a Patient With Severe Aortic Stenosis and Complex Multisystem Comorbidities\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eInfective endocarditis remains a serious condition associated with substantial morbidity and mortality, with in-hospital mortality rates reported to range between 15% and 30% despite advances in diagnostic imaging and antimicrobial therapy [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Early diagnosis is essential to prevent complications such as valvular destruction, systemic embolization, and heart failure.\u003c/p\u003e \u003cp\u003eEchocardiography plays a central role in diagnosis. Transthoracic echocardiography (TTE) is typically used as a first-line modality; however, its sensitivity may be limited in patients with structural heart disease or extensive valvular calcification [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTransesophageal echocardiography (TEE) provides superior spatial resolution and higher sensitivity for detecting vegetations and complications [10]. Current guidelines recommend TEE when clinical suspicion remains high despite negative TTE findings [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 57-year-old male with a complex medical history of hypertension, polycythemia vera complicated by Budd-Chiari syndrome (status post portocaval shunt), and severe anemia presented with progressive dyspnea and clinical features of acute decompensated heart failure.\u003c/p\u003e \u003cp\u003eOn admission, transthoracic echocardiography (TTE) demonstrated preserved left ventricular systolic function (LVEF 60\u0026ndash;65%), severe concentric left ventricular hypertrophy, and a heavily calcified trileaflet aortic valve with severe aortic stenosis (peak/mean gradient 171/134 mmHg, aortic valve area\u0026thinsp;~\u0026thinsp;0.8 cm\u0026sup2;) [Figure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e]. Mild mitral regurgitation was noted, with no evidence of intracardiac masses or vegetations [Figure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe patient was noted to have severe transfusion-dependent anemia, requiring multiple packed red blood cell transfusions with minimal clinical improvement. Peripheral blood smear revealed tear-drop cells, suggestive of underlying myelofibrosis secondary to polycythemia vera. Massive splenomegaly was also present.\u003c/p\u003e \u003cp\u003eDuring hospitalization, blood cultures grew Staphylococcus aureus, and intravenous cefazolin therapy was initiated. Despite appropriate antimicrobial treatment, the patient remained clinically unstable with persistent bacteremia and symptoms, raising high clinical suspicion for infective endocarditis.\u003c/p\u003e \u003cp\u003eTransesophageal echocardiography (TEE) was initially planned but deferred due to significant clinical deterioration, including severe respiratory distress requiring non-invasive ventilatory support.\u003c/p\u003e \u003cp\u003eOver the subsequent days, the patient developed rapid clinical worsening, with progression of mitral regurgitation leading to recurrent pulmonary edema and severe orthopnea.\u003c/p\u003e \u003cp\u003eA follow-up TEE performed approximately 20 days after the initial TTE revealed a large mobile vegetation measuring approximately 22 \u0026times; 12 mm attached to the posterior mitral leaflet (P2) [Figure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e], along with an additional smaller mobile mass on the anterior leaflet. These findings were associated with severe eccentric mitral regurgitation, supported by systolic flow reversal in the pulmonary veins [Figure \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe patient\u0026rsquo;s condition continued to deteriorate with recurrent episodes of pulmonary edema. Surgical intervention was considered; however, it was deemed prohibitively high risk given his multiple comorbidities and clinical instability. He was subsequently referred to a tertiary cardiac center for further evaluation and advanced management.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis case illustrates a clinically significant delay in the diagnosis of infective endocarditis in a high-risk patient with persistent Staphylococcus aureus bacteremia, complex structural heart disease, and systemic comorbidities. Despite a negative initial transthoracic echocardiography (TTE), clinical suspicion remained high due to persistent bacteremia, emphasizing the importance of integrating microbiological and clinical findings rather than relying solely on imaging [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTransthoracic echocardiography (TTE) has well-recognized limitations in detecting vegetations, with reported sensitivity ranging between 50% and 70%, particularly in patients with poor acoustic windows or heavily calcified valves [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In this case, severe calcific aortic stenosis likely impaired visualization and contributed to the failure to detect early vegetations.\u003c/p\u003e \u003cp\u003eIn contrast, transesophageal echocardiography (TEE) offers superior sensitivity exceeding 90% and remains the gold standard in cases with high clinical suspicion [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. According to current ESC guidelines, persistent Staphylococcus aureus bacteremia constitutes a major diagnostic criterion and should prompt early transesophageal echocardiography even when initial transthoracic imaging is negative [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAn important learning point from this case is the presence of persistent Staphylococcus aureus bacteremia, which is strongly associated with aggressive infective endocarditis and rapid valvular destruction [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Current evidence suggests that in such high-risk scenarios, early TEE should be strongly considered even in the presence of an initially negative TTE [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAdditionally, this case demonstrates a significant progression in disease severity within a relatively short time interval. The development of large vegetations measuring up to 22 \u0026times; 12 mm, along with progression to severe mitral regurgitation, raises the possibility of either rapid disease progression or initial under-detection. This finding reinforces the importance of early repeat imaging and timely escalation to TEE in high-risk patients.\u003c/p\u003e \u003cp\u003eFrom a clinical perspective, the delay in performing TEE due to patient instability reflects a common real-world challenge. However, earlier utilization may have facilitated earlier diagnosis and potentially altered management decisions, including earlier surgical evaluation.\u003c/p\u003e \u003cp\u003eVegetation size is a critical prognostic factor in infective endocarditis. Vegetations larger than 10 mm are associated with an increased risk of embolic events and adverse outcomes [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In this patient, the large vegetation burden further supports the need for early recognition and consideration of surgical intervention in accordance with current guidelines.\u003c/p\u003e \u003cp\u003eOverall, this case underscores the limitations of TTE in high-risk patients and highlights the necessity of early TEE when clinical suspicion remains high, particularly in the context of persistent bacteremia and complex structural heart disease [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis case emphasizes that a negative transthoracic echocardiogram does not exclude infective endocarditis in high-risk patients. Early transesophageal echocardiography should be strongly considered in cases of persistent clinical suspicion, particularly in the presence of Staphylococcus aureus bacteremia and complex structural heart disease.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cu\u003ePatient Consent\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatient consent was obtained for publication of this case report and accompanying images.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eHabib G, Lancellotti P, Antunes MJ, et al.2023 ESC Guidelines for the management of infective endocarditis. Eur Heart J. 2023;44(39):3948\u0026ndash;4042.\u003c/li\u003e\n \u003cli\u003eBaddour LM, Wilson WR, Bayer AS, et al. Infective endocarditis in adults: diagnosis, antimicrobial therapy, and management of complications. Circulation. 2015;132(15):1435\u0026ndash;1486.\u003c/li\u003e\n \u003cli\u003eCahill TJ, Prendergast BD.Infective endocarditis. Lancet. 2016;387(10021):882\u0026ndash;893.\u003c/li\u003e\n \u003cli\u003eDayer MJ, et al.Epidemiology and outcomes of infective endocarditis. J Am Coll Cardiol. 2022;79(10):1039\u0026ndash;1056.\u003c/li\u003e\n \u003cli\u003eEvangelista A, Gonzalez-Alujas MT.Echocardiography in infective endocarditis.Heart. 2016;102(7):543\u0026ndash;550.\u003c/li\u003e\n \u003cli\u003ePettersson GB, et al.Surgical treatment of infective endocarditis: AATS guidelines.J Thorac Cardiovasc Surg. 2019;157(2):e1\u0026ndash;e55.\u003c/li\u003e\n \u003cli\u003eHolland TL, et al.Staphylococcus aureus bacteremia: diagnosis and management.Clin Infect Dis. 2014;59(2):e10\u0026ndash;e52.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Rashid Hospital","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":"Infective endocarditis, transesophageal echocardiography, transthoracic echocardiography, mitral valve vegetation, aortic stenosis, case report","lastPublishedDoi":"10.21203/rs.3.rs-9214515/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9214515/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eInfective endocarditis is a life-threatening condition requiring early diagnosis and prompt management. Transthoracic echocardiography (TTE) is commonly used as an initial diagnostic tool; however, its sensitivity may be limited in patients with complex structural heart disease. We report a 57-year-old male with severe calcific aortic stenosis and multiple comorbidities who presented with persistent Staphylococcus aureus bacteremia. Initial TTE showed no evidence of vegetations despite high clinical suspicion.\u003c/p\u003e \u003cp\u003eDue to ongoing clinical deterioration, transesophageal echocardiography (TEE), performed 20 days later, revealed large mitral valve vegetations measuring up to 22 \u0026times; 12 mm, associated with progression to severe mitral regurgitation. This case highlights the limitations of TTE in high-risk patients and emphasizes the importance of early TEE, particularly in the presence of persistent bacteremia and clinical deterioration, to avoid delayed diagnosis and adverse outcomes.\u003c/p\u003e","manuscriptTitle":"Large Mitral Valve Infective Endocarditis Missed on Initial Transthoracic Echocardiography in a Patient With Severe Aortic Stenosis and Complex Multisystem Comorbidities","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-26 10:04:29","doi":"10.21203/rs.3.rs-9214515/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":"a433d8f9-ce07-4a2c-adc9-485b893169a0","owner":[],"postedDate":"March 26th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":65068437,"name":"Cardiac \u0026 Cardiovascular Systems"}],"tags":[],"updatedAt":"2026-03-26T10:04:30+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-26 10:04:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9214515","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9214515","identity":"rs-9214515","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}