{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T18:56:32Z","timestamp":1791831392027,"version":"4.3.4"},"reference-count":18,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T00:00:00Z","timestamp":1768176000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100020084","name":"Guangzhou Municipal Science and Technology Bureau","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100020084","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100012829","name":"Guangdong Provincial Hospital of Traditional Chinese Medicine","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100012829","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cardiovasc. Med."],"abstract":"<jats:p>\n                    A crossing patent foramen ovale (PFO) thrombus is a thrombus that straddles both atria through a PFO, also called a transseptal thrombus or an impending paradoxical embolism. Although rare, this condition represents a highly critical clinical emergency. Clinically, such thrombi are usually classified as primary intracardiac (\n                    <jats:italic>in situ<\/jats:italic>\n                    ) thrombosis or emboli in transit from the venous system. We report two contrasting cases of a thrombus straddling the foramen ovale documented with high-quality multimodality imaging and serial transesophageal echocardiography (TEE) during follow-up. Case 1 involved a 21-year-old man who presented with sudden severe dyspnea, profuse sweating, and transient loss of consciousness after a long-distance train journey. TEE demonstrated a large, highly mobile thrombus straddling the PFO with right heart enlargement and pulmonary hypertension, and CT pulmonary angiography (CTPA) confirmed extensive pulmonary embolism. During emergency surgery, thrombi were removed from the right atrium, PFO, left atrium, and pulmonary arteries with concomitant PFO closure. Subsequent targeted genetic testing revealed a heterozygous SERPINC1 nonsense variant classified as likely pathogenic for antithrombin deficiency, suggesting underlying hereditary thrombophilia. Case 2 involved a 75-year-old woman with hypertension and persistent atrial fibrillation who underwent TEE screening before planned catheter ablation, which revealed a small, relatively fixed thrombus confined to the PFO tunnel. She was managed conservatively with 20\u2005mg of rivaroxaban once daily, and serial TEE at 54 and 141 days revealed progressive thrombus regression without peripheral embolic events. These cases illustrate typical imaging features and clinical contexts that help distinguish an embolus in transit from a presumed\n                    <jats:italic>in situ<\/jats:italic>\n                    PFO thrombus and show how careful determination of the thrombus origin and nature can guide individualized management, help prevent catastrophic embolic events, and improve patient outcomes.\n                  <\/jats:p>","DOI":"10.3389\/fcvm.2025.1721995","type":"journal-article","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T07:32:18Z","timestamp":1768203138000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Case Report: Embolus in transit vs. in situ PFO thrombus"],"prefix":"10.3389","volume":"12","author":[{"given":"Bijing","family":"Li","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haoyuan","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huan","family":"Cen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sinan","family":"Chen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shengchun","family":"Shu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Peng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pengtao","family":"Sun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,1,12]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"151","DOI":"10.1111\/j.1540-8191.2010.01168.x","article-title":"Paradoxical embolus caught in transit through a patent foramen ovale","volume":"26","author":"Shah","year":"2011","journal-title":"J Card Surg"},{"key":"B2","doi-asserted-by":"publisher","first-page":"6752709","DOI":"10.1155\/2017\/6752709","article-title":"Saddle pulmonary embolism with thrombus in transit across a patent foramen ovale","volume":"2017","author":"Shepherd","year":"2017","journal-title":"Case Rep Cardiol"},{"key":"B3","doi-asserted-by":"publisher","first-page":"17","DOI":"10.1016\/s0025-6196(12)60336-x","article-title":"Incidence and size of patent foramen ovale during the first 10 decades of life: an autopsy study of 965 normal hearts","volume":"59","author":"Hagen","year":"1984","journal-title":"Mayo Clin Proc"},{"key":"B4","doi-asserted-by":"publisher","first-page":"4332","DOI":"10.1177\/0300060518789820","article-title":"Large thrombus-in-transit within a patent foramen ovale in a patient with pulmonary embolism: a case report","volume":"46","author":"Lu","year":"2018","journal-title":"J Int Med Res"},{"key":"B5","doi-asserted-by":"publisher","first-page":"26","DOI":"10.1186\/1476-7120-5-26","article-title":"Pulmonary embolism and patent foramen ovale thrombosis: the key role of TEE","volume":"5","author":"Serra","year":"2007","journal-title":"Cardiovasc Ultrasound"},{"key":"B6","doi-asserted-by":"publisher","first-page":"79","DOI":"10.1186\/s43044-020-00112-x","article-title":"Management of a huge right atrial thrombus in a patient with multiple comorbidities","volume":"72","author":"Selwanos","year":"2020","journal-title":"Egypt Heart J"},{"key":"B7","doi-asserted-by":"publisher","first-page":"4902","DOI":"10.12998\/wjcc.v8.i20.4902","article-title":"Thrombus straddling a patent foramen ovale and pulmonary embolism: a case report","volume":"8","author":"Huang","year":"2020","journal-title":"World J Clin Cases"},{"key":"B8","doi-asserted-by":"publisher","first-page":"e946997","DOI":"10.12659\/ajcr.946997","article-title":"Paradoxical embolism through patent foramen ovale: a case report of thrombus in transit","volume":"26","author":"Lok","year":"2025","journal-title":"Am J Case Rep"},{"key":"B9","doi-asserted-by":"publisher","first-page":"88","DOI":"10.1007\/s42399-023-01426-y","article-title":"Transit thrombus in a patent foramen ovale \u2014 time is running out: a case report","volume":"5","author":"Kronberg","year":"2023","journal-title":"SN Compr Clin Med"},{"key":"B10","doi-asserted-by":"publisher","first-page":"e55","DOI":"10.1016\/j.ijcard.2007.11.007","article-title":"Thrombus crossing through a patent foramen ovale","volume":"133","author":"Ozdogru","year":"2009","journal-title":"Int J Cardiol"},{"key":"B11","doi-asserted-by":"publisher","first-page":"2335","DOI":"10.1016\/j.jacc.2018.02.046","article-title":"Cryptogenic stroke and high-risk patent foramen ovale: the DEFENSE-PFO trial","volume":"71","author":"Lee","year":"2018","journal-title":"J Am Coll Cardiol"},{"key":"B12","doi-asserted-by":"publisher","first-page":"28","DOI":"10.1186\/s43057-022-00089-0","article-title":"Anesthetic management and the role of TEE in the entrapment of a paradoxical embolus by a patent foramen ovale","volume":"30","author":"Davis","year":"2022","journal-title":"Cardiothorac Surg"},{"key":"B13","doi-asserted-by":"publisher","first-page":"776","DOI":"10.4070\/kcj.2016.0295","article-title":"Systematic review of treatment for trapped thrombus in patent foramen ovale","volume":"47","author":"Seo","year":"2017","journal-title":"Korean Circ J"},{"key":"B14","doi-asserted-by":"publisher","first-page":"e035838","DOI":"10.1161\/JAHA.124.035838","article-title":"Right atrial septal in situ microthrombus: a potential novel cause of patent foramen ovale-associated stroke","volume":"13","author":"Zhu","year":"2024","journal-title":"J Am Heart Assoc"},{"key":"B15","doi-asserted-by":"publisher","first-page":"e52535","DOI":"10.7759\/cureus.52535","article-title":"A case report of under-recognized conditions in pulmonary embolism: patent foramen ovale and right ventricular thrombus","volume":"16","author":"Sera","year":"2024","journal-title":"Cureus"},{"key":"B16","doi-asserted-by":"publisher","first-page":"104819","DOI":"10.1016\/j.jaccas.2025.104819","article-title":"Pulmonary embolism with serpentine thrombus straddling a patent foramen ovale","volume":"30","author":"Wang","year":"2025","journal-title":"JACC Case Rep"},{"key":"B17","doi-asserted-by":"publisher","first-page":"e87048","DOI":"10.7759\/cureus.87048","article-title":"Caught in transit: thrombus traversing a patent foramen ovale","volume":"17","author":"Nuvvula","year":"2025","journal-title":"Cureus"},{"key":"B18","doi-asserted-by":"publisher","first-page":"2116","DOI":"10.1001\/jama.2021.4359","article-title":"Preliminary investigation of in situ thrombus within patent foramen ovale in patients with and without stroke","volume":"325","author":"Yan","year":"2021","journal-title":"JAMA"}],"container-title":["Frontiers in Cardiovascular Medicine"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcvm.2025.1721995\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T07:32:25Z","timestamp":1768203145000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fcvm.2025.1721995\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,12]]},"references-count":18,"alternative-id":["10.3389\/fcvm.2025.1721995"],"URL":"https:\/\/doi.org\/10.3389\/fcvm.2025.1721995","relation":{},"ISSN":["2297-055X"],"issn-type":[{"value":"2297-055X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,12]]},"article-number":"1721995"}}