A case of ultrasound-guided intrasac thrombin injection for iatrogenic femoral artery pseudoaneurysm

A case of ultrasound-guided intrasac thrombin injection for iatrogenic femoral artery pseudoaneurysm | 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 A case of ultrasound-guided intrasac thrombin injection for iatrogenic femoral artery pseudoaneurysm Musheng Rao, Bin Peng, Hui Rao, Lanting Deng This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6729377/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 We report a case of femoral artery pseudoaneurysm (FAP) following endovascular embolization of a carotid aneurysm, successfully treated with ultrasound-guided percutaneous thrombin injection (UGTI). A 67-year-old woman developed FAP (3.85×3.92×2.64 cm) postoperatively, with initial compression therapy failing to resolve the lesion. Multidisciplinary team consultation led to UGTI, employing thrombin’s coagulation cascade to induce thrombosis, occluding the aneurysm neck. The procedure involved slow tranexamic acid injection under ultrasound guidance, resulting in complete thrombosis (anechoic-to-isoechoic transition) and resolution of blood flow on follow-up imaging. Notably, the pseudoaneurysm regressed significantly (5.02×1.98 cm) within two days, with sustained recovery at one month. This case highlights UGTI’s efficacy as a minimally invasive, rapid-response alternative to surgical repair, particularly for compression-refractory FAPs. The innovative use of real-time ultrasound monitoring ensured precise thrombin delivery while avoiding critical vascular structures, underscoring the technique’s safety and reproducibility. Our findings reinforce UGTI’s role in optimizing post-interventional vascular complication management. femoral artery pseudoaneurysm interventional therapy thrombin injection Figures Figure 1 Figure 2 Introduction Femoral artery pseudoaneurysm (FAP) is a vascular complication arising from percutaneous femoral artery puncture, characterized by blood leakage through an arterial wall defect into surrounding tissues, forming a pseudoaneurysmal sac. Hemodynamic forces create a "to-and-fro" flow phenomenon, with blood entering the sac during systole and partially returning during diastole [1]. The therapeutic mechanism of ultrasound-guided percutaneous thrombin injection (UGTI) relies on thrombin's positive feedback effect, which activates coagulation factors and facilitates the conversion of prothrombin to thrombin. This process then catalyzes the conversion of fibrinogen to fibrin, ultimately inducing thrombosis within the pseudoaneurysm sac. The formed thrombus effectively occludes the aneurysm neck, persistently interrupting the jet flow originating from the femoral artery puncture site, thus accomplishing pseudoaneurysm embolization. Case report A 67-year-old woman presented with a 1-month history of headache. Digital subtraction angiography (DSA) identified a left internal carotid artery aneurysm (13.3×8.0 ×4.5 mm), which was subsequently treated with endovascular embolization using a flow-diverting stent. Postoperatively, a femoral artery compression device was applied and removed after 24 hours. On day 3,the patient presented with cutaneous ecchymosis at the puncture site.Color Doppler ultrasound demonstrated a pseudoaneurysm (3.85×3.92×2.64 cm) in the right common femoral artery, accompanied by intrasaccular thrombosis(Figure 1). Despite reapplication of the compression device, a repeat ultrasound after 2 days showed slight enlargement of the anechoic area (4.40×3.97×3.18 cm) (Figure 2). Following multidisciplinary team (MDT) consultation, ultrasound-guided percutaneous thrombin injection was performed. The patient was positioned supine, and the pseudoaneurysm cavity was located via ultrasound. After disinfection and draping, the puncture needle was guided into the cavity while avoiding the aneurysm neck. Proximal femoral artery compression was applied to occlude blood flow，and a slow injection of 5 mL tranexamic acid was administered, followed by sustained compression for 5 minutes. Ultrasound monitoring showed the anechoic area transforming into an isoechoic region, with no blood flow signals detected on color Doppler flow imaging (CDFI) (Figure 2). The patient experienced only mild pain during the procedure. Two days later, ultrasound revealed a reduced anechoic area (5.02×1.98 cm) (Figure 2) without blood flow communication with the femoral artery on CDFI. At the 1-month follow-up, the mixed-echo mass at the right groin was significantly reduced, and the patient recovered well without complications. Discussion With advancements in interventional techniques, particularly in endovascular devices and methods, the treatment of cerebrovascular and peripheral vascular diseases has shifted toward minimally invasive therapies. Consequently, femoral artery puncture, as the primary access route, has gained attention for its safety and complication management.FAP is a common complication of transfemoral access[2], especially in cerebral angiography and endovascular interventions using the Seldinger technique. Its incidence has risen with the increasing volume of such procedures. Key risk factors include: 1.Use of anticoagulant and antiplatelet agents For patients scheduled for stent implantation, dual antiplatelet therapy (DAPT)—typically combining aspirin and clopidogrel (or ticagrelor)—is required perioperatively to prevent thrombotic events[3]. However, these agents inhibit platelet aggregation, thereby artificially inducing a bleeding tendency, which may impair vascular endothelial repair at the puncture site and consequently increase the risk of FAP. 2.Puncture Technique and Device-Related Factors A low puncture site (below the femoral artery bifurcation) lacks the bony support of the pubic ramus, reducing the effectiveness of compression hemostasis. Repeated puncture attempts may cause multiple arterial wall injuries. Inadvertent puncture of the superficial femoral artery (SFA) or deep femoral artery (DFA) increases the risk of FAP[4].The use of large-bore introducer sheaths (≥8F) significantly elevates the risk of vascular wall injury. Following sheath removal, if the arterial puncture site fails to close promptly, persistent blood extravasation into perivascular tissues may occur. This can lead to the formation of a pulsatile hematoma encapsulated by a fibrous membrane, ultimately progressing to FAP. 3.Hypertension and other hazardous factors Poorly controlled chronic hypertension leads to vascular intimal fibrosis and reduced elasticity. Perioperative blood pressure fluctuations create sustained pressure gradients across the arterial wall at the puncture site, delaying hole closure. Additionally, increased subcutaneous adipose tissue thickness (BMI ≥30 kg/m²) not only compromises compression hemostasis efficacy but also raises the risk of post-procedural compression device displacement. Premature ambulation or non-compliance with prescribed bed rest may contribute to localized hematoma formation。 The incidence of FAP ranges from 0.5% in diagnostic procedures to 9% in therapeutic interventions, with an overall rate of 1%-7% [5][6].Color Doppler ultrasound is the primary diagnostic tool, revealing turbulent flow within the aneurysm and the characteristic "to-and-fro" waveform at the neck. FAP has a low spontaneous resolution rate and can lead to severe complications, including neurovascular compression, tissue necrosis, rupture, or thromboembolic events. Current treatments include ultrasound-guided thrombin injection (UGTI), endovascular stent-graft placement, and surgical repair. UGTI, introduced by Fellmeth et al. in 1991 [7], has become widely used due to its safety and efficacy, with success rates exceeding 90% [8].UGTI relies on thrombin's ability to activate coagulation factors, converting fibrinogen to fibrin and inducing thrombosis within the aneurysm sac. This occludes the aneurysm neck, stopping blood flow and embolizing the pseudoaneurysm. The procedure requires continuous ultrasound guidance to monitor hemodynamics, aneurysm morphology, and needle position. Precautions include compressing the femoral artery proximal to the aneurysm, avoiding normal vessels, and injecting thrombin slowly (0.1–0.2 ml/s) at a recommended dose of 2–5 ml [9]. Thrombosis typically occurs within minutes, and injection should cease once 3/4 of the sac is filled to avoid complications. Conclusion While UGTI is highly effective, it carries risks, primarily distal limb artery thrombosis due to thrombin reflux. However, strict adherence to protocols and proper technique minimizes complications, ensuring safe and beneficial outcomes for most patients. Declarations Funding Declaration ： There is no Funding in my research Author Contribution Declaration ： Musheng Rao(First Author)：Write original draft Bin Peng：Describe the patient's course of treatment Hui Rao：Search References Lanting Deng（Correspondence Author）：Review draft Declaration of competing interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Ethical compliance statement: We confirm that we have read the journal’s position on issues involved in ethical publication and affirm this work is consistent with those guidelines. Ethics approval of this manuscript was obtained by the ethics committee Patient consent was obtained for firgure publication. References Yoo J , Gu D , Rhee I .Open Access Successful Treatment of an Iatrogenic Giant Femoral Artery Pseudoaneurysm With Percutaneous Thrombin Injection[J]. 2013. Seino N , Ito H , Uchida M ,et al.A Case of High-Level Femoral Artery Bifurcation Contributing to Puncture-Site Pseudoaneurysm Following Neuroendovascular Intervention[J].The St. Marianna Medical Journal, 2022, 50(3):85-91.DOI:10.14963/stmari.50.85. Lee S P , Suh J W , Park K W ,et al.Study design and rationale of 'Influence of Cilostazol-based triple anti-platelet therapy on ischemic complication after drug-eluting stent implantation (CILON-T)' study: A multicenter randomized trial evaluating the efficacy of Cilostazol on ischemic vasc[J].Trials, 2010, 11(1):87-87.DOI:10.1186/1745-6215-11-87. Chou S B , Tsen J H , Hung C F ,et al.Transcatheter arterial embolization of pseudoaneurysm of the internal maxillary artery after mandibular osteotomy[J].Tzu Chi Medical Journal, 2003, 15(3):191-194.DOI:10.6440/TZUCMJ.200306.0191. 37(18):3.DOI:10.3969/j.issn.1671-8348.2008.18.009. Righini M ,I. Quéré, Laroche J P .[Treatment of postcatheterization femoral false aneurysms].[J].Journal Des Maladies Vasculaires, 2004, 29(2):63-72.DOI:10.1016/S0398-0499(04)96717-0. Corso R , Rampoldi A , Riolo F ,et al.Radiodiagnostics-Vascular radiology-Occlusion of postcatheterisation femoral pseudoaneurysms with percutaneous thrombin injection under ultrasound guidance (Original article)[J]. 2004. Fellmeth B D , Roberts A C , Bookstein J J ,et al.Postangiographic femoral artery injuries: nonsurgical repair with US-guided compression.[J].Radiology, 1991, 178(3):671-675.DOI:10.1148/radiology.178.3.1994400. Yinyong L I , Jiong G , Yun X ,et al.Ultra-guided percutaneous thrombin injection for treatment of iatrogenic pseudoaneurysms of the body[J].China Medicine and Pharmacy, 2013. Vlachou P A , Karkos C D , Bains S ,et al.Percutaneous ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms[J].European Journal of Radiology, 2011, 77(1): 172-174. DOI:10.1016/j.ejrad.2009.06.032.15(3):5. 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-6729377","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":486009624,"identity":"3e00985e-1157-4c35-89e2-2920e91c282b","order_by":0,"name":"Musheng Rao","email":"","orcid":"","institution":"The Central Hospital of Xiaogan, Xiaogan Hospital Affiliate to Wuhan University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Musheng","middleName":"","lastName":"Rao","suffix":""},{"id":486009626,"identity":"e5e68d78-db0c-43f9-a7e9-7cc48e38fc33","order_by":1,"name":"Bin Peng","email":"","orcid":"","institution":"The Central Hospital of Xiaogan, Xiaogan Hospital Affiliate to Wuhan University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Bin","middleName":"","lastName":"Peng","suffix":""},{"id":486009629,"identity":"2d26913d-2700-4fba-9abe-9f515b424252","order_by":2,"name":"Hui Rao","email":"","orcid":"","institution":"The Central Hospital of Xiaogan, Xiaogan Hospital Affiliate to Wuhan University of Science and Technology","correspondingAuthor":false,"prefix":"","firstName":"Hui","middleName":"","lastName":"Rao","suffix":""},{"id":486009631,"identity":"98bea2d1-b74f-4baa-8ac5-2c40ba605761","order_by":3,"name":"Lanting Deng","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYBACNvmDjQ8+8LDJsTEzHyBOC58E82HDGTJ8xvzsbQnEaZGTYEsT5rGRS5zZc8aASIdJ95gx8+SYMW64kfPxxhsGOzndBkJaZM6YPZxzJo3Z4EbuZss5DMnGZgcIaWHIMTd423OMDahlmzQPw4HEbURoMZPg/fefx+BGzjMitUikpUny8LBJSPacYSNSC89hYCDzsBkAA9nYco4BEX6Rb28ER2V9GzPzwxtvKuzkCGpBARI8REYNshZSdYyCUTAKRsGIAACxMD9n0M1GyAAAAABJRU5ErkJggg==","orcid":"","institution":"The Central Hospital of Xiaogan, Xiaogan Hospital Affiliate to Wuhan University of Science and Technology","correspondingAuthor":true,"prefix":"","firstName":"Lanting","middleName":"","lastName":"Deng","suffix":""}],"badges":[],"createdAt":"2025-05-23 05:08:19","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6729377/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6729377/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87320598,"identity":"ad07f65c-89f4-4593-b967-390a9d26452a","added_by":"auto","created_at":"2025-07-22 16:30:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":156425,"visible":true,"origin":"","legend":"\u003cp\u003ePseudoaneurysm was formed in the right femoral artery.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-6729377/v1/391da77afa2278b56d61b09d.png"},{"id":87320595,"identity":"a223a8c8-3688-447d-9606-46eaaa1285a9","added_by":"auto","created_at":"2025-07-22 16:30:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":691711,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(a, b)\u003c/strong\u003e There was still a pseudoaneurysm after re-compression of the puncture site. \u003cstrong\u003e(c, d)\u003c/strong\u003e There was no blood flow communication between the aneurysm cavity and the right common femoral artery after injection. \u003cstrong\u003e(e, f)\u003c/strong\u003e There was no blood flow communication between the aneurysm cavity and the parent artery by color doppler ultrasound.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-6729377/v1/0834bbd3df58010ed1110848.png"},{"id":91158462,"identity":"bed190e4-a2c5-4567-9f50-75dcc1445db3","added_by":"auto","created_at":"2025-09-12 08:32:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1202696,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6729377/v1/30ede2f6-5288-4923-a0ad-24c65dfe6444.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A case of ultrasound-guided intrasac thrombin injection for iatrogenic femoral artery pseudoaneurysm","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFemoral artery pseudoaneurysm (FAP) is a vascular complication arising from percutaneous femoral artery puncture, characterized by blood leakage through an arterial wall defect into surrounding tissues, forming a pseudoaneurysmal sac. Hemodynamic forces create a \u0026quot;to-and-fro\u0026quot; flow phenomenon, with blood entering the sac during systole and partially returning during diastole [1]. The therapeutic mechanism of ultrasound-guided percutaneous thrombin injection (UGTI) relies on thrombin\u0026apos;s positive feedback effect, which activates coagulation factors and facilitates the conversion of prothrombin to thrombin. This process then catalyzes the conversion of fibrinogen to fibrin, ultimately inducing thrombosis within the pseudoaneurysm sac. The formed thrombus effectively occludes the aneurysm neck, persistently interrupting the jet flow originating from the femoral artery puncture site, thus accomplishing pseudoaneurysm embolization.\u003c/p\u003e\n"},{"header":"Case report","content":"\u003cp\u003eA 67-year-old woman presented with a 1-month history of headache. Digital subtraction angiography (DSA) identified a left internal carotid artery aneurysm (13.3\u0026times;8.0\u0026nbsp;\u0026times;4.5 mm), which was subsequently treated with endovascular embolization using a flow-diverting stent. Postoperatively, a femoral artery compression device was applied and removed after 24 hours.\u003c/p\u003e\n\u003cp\u003eOn day 3,the patient presented with cutaneous ecchymosis at the puncture site.Color Doppler ultrasound demonstrated a pseudoaneurysm (3.85\u0026times;3.92\u0026times;2.64 cm) in the right common femoral artery, accompanied by intrasaccular thrombosis(Figure 1). Despite reapplication of the compression device, a repeat ultrasound after 2 days showed slight enlargement of the anechoic area (4.40\u0026times;3.97\u0026times;3.18 cm) (Figure 2).\u003c/p\u003e\n\u003cp\u003eFollowing multidisciplinary team (MDT) consultation, ultrasound-guided percutaneous thrombin injection was performed. The patient was positioned supine, and the pseudoaneurysm cavity was located via ultrasound. After disinfection and draping, the puncture needle was guided into the cavity while avoiding the aneurysm neck. Proximal femoral artery compression was applied to occlude blood flow，and a slow injection of 5 mL tranexamic acid was administered, followed by sustained compression for 5 minutes. Ultrasound monitoring showed the anechoic area transforming into an isoechoic region, with no blood flow signals detected on color Doppler flow imaging (CDFI) (Figure 2). The patient experienced only mild pain during the procedure.\u003c/p\u003e\n\u003cp\u003eTwo days later, ultrasound revealed a reduced anechoic area (5.02\u0026times;1.98 cm) (Figure 2) without blood flow communication with the femoral artery on CDFI. At the 1-month follow-up, the mixed-echo mass at the right groin was significantly reduced, and the patient recovered well without complications.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWith advancements in interventional techniques, particularly in endovascular devices and methods, the treatment of cerebrovascular and peripheral vascular diseases has shifted toward minimally invasive therapies. Consequently, femoral artery puncture, as the primary access route, has gained attention for its safety and complication management.FAP is a common complication of transfemoral access[2], especially in cerebral angiography and endovascular interventions using the Seldinger technique. Its incidence has risen with the increasing volume of such procedures.\u003c/p\u003e\n\u003cp\u003e Key risk factors include: \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e1.Use of anticoagulant and antiplatelet agents\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor patients scheduled for stent implantation, dual antiplatelet therapy (DAPT)\u0026mdash;typically combining aspirin and clopidogrel (or ticagrelor)\u0026mdash;is required perioperatively to prevent thrombotic\u0026nbsp;events[3].\u0026nbsp;However, these agents inhibit platelet aggregation, thereby artificially inducing a bleeding tendency, which may impair vascular endothelial repair at the puncture site and consequently increase the risk of FAP.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.Puncture Technique and Device-Related Factors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA\u0026nbsp;low puncture site\u0026nbsp;(below the femoral artery bifurcation) lacks the\u0026nbsp;bony support of the pubic ramus, reducing the effectiveness of compression hemostasis.\u0026nbsp;Repeated puncture attempts\u0026nbsp;may cause multiple arterial wall injuries.\u0026nbsp;Inadvertent puncture of the superficial femoral artery (SFA) or deep femoral artery (DFA)\u0026nbsp;increases the risk of FAP[4].The use of\u0026nbsp;large-bore introducer sheaths (\u0026ge;8F)\u0026nbsp;significantly elevates the risk of vascular wall injury. Following sheath removal, if the arterial puncture site fails to close promptly,\u0026nbsp;persistent blood extravasation\u0026nbsp;into perivascular tissues may occur. This can lead to the formation of a\u0026nbsp;pulsatile hematoma\u0026nbsp;encapsulated by a fibrous membrane, ultimately progressing to FAP.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.Hypertension and other hazardous factors\u003c/strong\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePoorly controlled chronic hypertension leads to vascular intimal fibrosis and reduced elasticity. Perioperative blood pressure fluctuations create sustained pressure gradients across the arterial wall at the puncture site, delaying hole closure. Additionally, increased subcutaneous adipose tissue thickness (BMI \u0026ge;30 kg/m\u0026sup2;) not only compromises compression hemostasis efficacy but also raises the risk of post-procedural compression device displacement. Premature ambulation or non-compliance with prescribed bed rest may contribute to localized hematoma formation。\u003c/p\u003e\n\u003cp\u003eThe incidence of FAP ranges from 0.5% in diagnostic procedures to 9% in therapeutic interventions, with an overall rate of 1%-7%\u0026nbsp;[5][6].Color Doppler ultrasound is the primary diagnostic tool, revealing turbulent flow within the aneurysm and the characteristic \u0026quot;to-and-fro\u0026quot; waveform at the neck. FAP has a low spontaneous resolution rate and can lead to severe complications, including neurovascular compression, tissue necrosis, rupture, or thromboembolic events. Current treatments include ultrasound-guided thrombin injection (UGTI), endovascular stent-graft placement, and surgical repair. UGTI, introduced by Fellmeth et al. in 1991\u0026nbsp;[7], has become widely used due to its safety and efficacy, with success rates exceeding 90%\u0026nbsp;[8].UGTI relies on thrombin\u0026apos;s ability to activate coagulation factors, converting fibrinogen to fibrin and inducing thrombosis within the aneurysm sac. This occludes the aneurysm neck, stopping blood flow and embolizing the pseudoaneurysm. The procedure requires continuous ultrasound guidance to monitor hemodynamics, aneurysm morphology, and needle position. Precautions include compressing the femoral artery proximal to the aneurysm, avoiding normal vessels, and injecting thrombin slowly (0.1\u0026ndash;0.2 ml/s) at a recommended dose of 2\u0026ndash;5 ml\u0026nbsp;[9]. Thrombosis typically occurs within minutes, and injection should cease once 3/4 of the sac is filled to avoid complications.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWhile UGTI is highly effective, it carries risks, primarily distal limb artery thrombosis due to thrombin reflux. However, strict adherence to protocols and proper technique minimizes complications, ensuring safe and beneficial outcomes for most patients.\u003c/p\u003e\n"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding Declaration\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is no Funding in my research\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003cstrong\u003eAuthor Contribution Declaration\u003c/strong\u003e\u003cstrong\u003e：\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMusheng Rao(First Author)：Write original draft\u003c/p\u003e\n\u003cp\u003eBin Peng：Describe the patient\u0026apos;s course of treatment\u003c/p\u003e\n\u003cp\u003eHui Rao：Search References\u003c/p\u003e\n\u003cp\u003eLanting Deng（Correspondence Author）：Review draft\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eDeclaration of competing interest:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this\u0026nbsp;paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eEthical compliance statement:\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe confirm that we have read the journal\u0026rsquo;s position on issues involved in ethical publication and affirm this work is consistent with those guidelines. Ethics approval of this manuscript was obtained by the ethics committee Patient consent was obtained for firgure publication.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eYoo J , Gu D , Rhee I .Open Access Successful Treatment of an Iatrogenic Giant Femoral Artery Pseudoaneurysm With Percutaneous Thrombin Injection[J]. 2013.\u003c/li\u003e\n\u003cli\u003eSeino N , Ito H , Uchida M ,et al.A Case of High-Level Femoral Artery Bifurcation Contributing to Puncture-Site Pseudoaneurysm Following Neuroendovascular Intervention[J].The St. Marianna Medical Journal, 2022, 50(3):85-91.DOI:10.14963/stmari.50.85.\u003c/li\u003e\n\u003cli\u003eLee S P , Suh J W , Park K W ,et al.Study design and rationale of \u0026apos;Influence of Cilostazol-based triple anti-platelet therapy on ischemic complication after drug-eluting stent implantation (CILON-T)\u0026apos; study: A multicenter randomized trial evaluating the efficacy of Cilostazol on ischemic vasc[J].Trials, 2010, 11(1):87-87.DOI:10.1186/1745-6215-11-87.\u003c/li\u003e\n\u003cli\u003eChou S B , Tsen J H , Hung C F ,et al.Transcatheter arterial embolization of pseudoaneurysm of the internal maxillary artery after mandibular osteotomy[J].Tzu Chi Medical Journal, 2003, 15(3):191-194.DOI:10.6440/TZUCMJ.200306.0191. 37(18):3.DOI:10.3969/j.issn.1671-8348.2008.18.009.\u003c/li\u003e\n\u003cli\u003eRighini M ,I. Qu\u0026eacute;r\u0026eacute;, Laroche J P .[Treatment of postcatheterization femoral false aneurysms].[J].Journal Des Maladies Vasculaires, 2004, 29(2):63-72.DOI:10.1016/S0398-0499(04)96717-0.\u003c/li\u003e\n\u003cli\u003eCorso R , Rampoldi A , Riolo F ,et al.Radiodiagnostics-Vascular radiology-Occlusion of postcatheterisation femoral pseudoaneurysms with percutaneous thrombin injection under ultrasound guidance (Original article)[J]. 2004.\u003c/li\u003e\n\u003cli\u003eFellmeth B D , Roberts A C , Bookstein J J ,et al.Postangiographic femoral artery injuries: nonsurgical repair with US-guided compression.[J].Radiology, 1991, 178(3):671-675.DOI:10.1148/radiology.178.3.1994400.\u003c/li\u003e\n\u003cli\u003eYinyong L I , Jiong G , Yun X ,et al.Ultra-guided percutaneous thrombin injection for treatment of iatrogenic pseudoaneurysms of the body[J].China Medicine and Pharmacy, 2013.\u003c/li\u003e\n\u003cli\u003eVlachou P A , Karkos C D , Bains S ,et al.Percutaneous ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms[J].European Journal of Radiology, 2011, 77(1): 172-174. DOI:10.1016/j.ejrad.2009.06.032.15(3):5. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"femoral artery pseudoaneurysm, interventional therapy, thrombin injection","lastPublishedDoi":"10.21203/rs.3.rs-6729377/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6729377/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"We report a case of femoral artery pseudoaneurysm (FAP) following endovascular embolization of a carotid aneurysm, successfully treated with ultrasound-guided percutaneous thrombin injection (UGTI). A 67-year-old woman developed FAP (3.85×3.92×2.64 cm) postoperatively, with initial compression therapy failing to resolve the lesion. Multidisciplinary team consultation led to UGTI, employing thrombin’s coagulation cascade to induce thrombosis, occluding the aneurysm neck. The procedure involved slow tranexamic acid injection under ultrasound guidance, resulting in complete thrombosis (anechoic-to-isoechoic transition) and resolution of blood flow on follow-up imaging. Notably, the pseudoaneurysm regressed significantly (5.02×1.98 cm) within two days, with sustained recovery at one month. This case highlights UGTI’s efficacy as a minimally invasive, rapid-response alternative to surgical repair, particularly for compression-refractory FAPs. The innovative use of real-time ultrasound monitoring ensured precise thrombin delivery while avoiding critical vascular structures, underscoring the technique’s safety and reproducibility. Our findings reinforce UGTI’s role in optimizing post-interventional vascular complication management.","manuscriptTitle":"A case of ultrasound-guided intrasac thrombin injection for iatrogenic femoral artery pseudoaneurysm","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-22 16:22:38","doi":"10.21203/rs.3.rs-6729377/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":"84889b80-32b6-4bfe-b0ca-eb0b759984a4","owner":[],"postedDate":"July 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-12T08:23:52+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-22 16:22:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6729377","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6729377","identity":"rs-6729377","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}