{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T18:44:10Z","timestamp":1785437050146,"version":"3.56.0"},"reference-count":20,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T00:00:00Z","timestamp":1783900800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"crossref","award":["RS-2024-00455661"],"award-info":[{"award-number":["RS-2024-00455661"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea","doi-asserted-by":"crossref","award":["RS-2024-00440824"],"award-info":[{"award-number":["RS-2024-00440824"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"crossref"}]},{"award":["RS-2024-00455661"],"award-info":[{"award-number":["RS-2024-00455661"]}],"id":[{"id":"https:\/\/ror.org\/013aysd81","id-type":"ROR","asserted-by":"publisher"}]},{"award":["RS-2024-00440824"],"award-info":[{"award-number":["RS-2024-00440824"]}],"id":[{"id":"https:\/\/ror.org\/013aysd81","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background: In low-flow, low-gradient aortic stenosis (LFLG AS), restricted aortic valve opening may represent either fixed valvular obstruction or flow-dependent incomplete leaflet opening due to reduced forward flow. Aortic stenosis (AS) and transthyretin cardiac amyloidosis (ATTR-CM) may coexist, making it difficult to distinguish myocardial disease\u2013driven low-flow physiology from clinically relevant valvular obstruction. Case Presentation: An 88-year-old man presented with decompensated heart failure and paradoxical LFLG AS. Dobutamine stress echocardiography (DSE) failed to restore normal flow, and the calculated aortic valve area remained within the severe range despite stress. Computed tomography showed a low aortic valve calcium score (AVCS) of 313 Agatston units, leaving true-severe versus pseudo-severe AS indeterminate. Further evaluation confirmed wild-type ATTR-CM. Because the contribution of AS to heart failure was uncertain, the patient was initially managed with optimized heart failure therapy. Approximately two years later, he was readmitted with recurrent acute decompensated heart failure, severe left ventricular systolic dysfunction, dobutamine dependency, end-organ congestion, and a classical LFLG AS phenotype. Although AS severity remained indeterminate, a clinically relevant valvular afterload component could not be excluded. At that time, tafamidis was not immediately available because of local access limitations. Because left ventricular assist device implantation and heart transplantation were not feasible and surgical aortic valve replacement carried prohibitive risk, transcatheter aortic valve implantation (TAVI) was performed after discussion by the Heart Team. Left ventricular ejection fraction improved early after TAVI, from 19.9% before the procedure to 29.4% at 3 days and 44.1% at 35 days. At 1-year follow-up, left ventricular ejection fraction remained improved at 51%, and more than two years after TAVI, the patient continues regular outpatient follow-up without recurrent heart failure hospitalization. Conclusions: In ATTR-CM with LFLG AS, DSE and AVCS may not definitively determine AS severity. Carefully selected TAVI, combined with ATTR-directed and optimized heart failure therapy, may be associated with early left ventricular functional recovery and sustained clinical improvement.<\/jats:p>","DOI":"10.3390\/diagnostics16142177","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T09:51:09Z","timestamp":1783936269000},"page":"2177","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Low-Flow, Low-Gradient Aortic Stenosis in Transthyretin Cardiac Amyloidosis: Diagnostic and Therapeutic Challenges\u2014A Case Report"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-8525-9547","authenticated-orcid":false,"given":"So-Young","family":"Lee","sequence":"first","affiliation":[{"name":"Division of Cardiology, Department of Internal Medicine, Seoul St. Mary\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"},{"name":"Catholic Research Institute for Intractable Cardiovascular Disease, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0224-5178","authenticated-orcid":false,"given":"Mi-Hyang","family":"Jung","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Department of Internal Medicine, Seoul St. Mary\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"},{"name":"Catholic Research Institute for Intractable Cardiovascular Disease, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6933-2957","authenticated-orcid":false,"given":"Woo-Baek","family":"Chung","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Department of Internal Medicine, Seoul St. Mary\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"},{"name":"Catholic Research Institute for Intractable Cardiovascular Disease, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5102-9212","authenticated-orcid":false,"given":"Hae Ok","family":"Jung","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Department of Internal Medicine, Seoul St. Mary\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"},{"name":"Catholic Research Institute for Intractable Cardiovascular Disease, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0998-503X","authenticated-orcid":false,"given":"Jong-Chan","family":"Youn","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Department of Internal Medicine, Seoul St. Mary\u2019s Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"},{"name":"Catholic Research Institute for Intractable Cardiovascular Disease, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1845","DOI":"10.1016\/j.jacc.2012.06.051","article-title":"Low-flow, low-gradient aortic stenosis with normal and depressed left ventricular ejection fraction","volume":"60","author":"Pibarot","year":"2012","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1161\/CIRCIMAGING.113.001375","article-title":"Aortic stenosis suspected to be severe despite low gradients","volume":"7","author":"Pibarot","year":"2014","journal-title":"Circ. Cardiovasc. Imaging"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"100263","DOI":"10.1016\/j.jacadv.2023.100263","article-title":"Discordant Low-Gradient Aortic Stenosis with Preserved Left Ventricular Ejection Fraction: Setting the Record Straight","volume":"2","author":"Pibarot","year":"2023","journal-title":"JACC Adv."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"4635","DOI":"10.1093\/eurheartj\/ehaf194","article-title":"2025 ESC\/EACTS Guidelines for the management of valvular heart disease","volume":"46","author":"Praz","year":"2025","journal-title":"Eur. Heart J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2638","DOI":"10.1016\/j.jacc.2019.09.056","article-title":"Aortic Stenosis and Cardiac Amyloidosis: JACC Review Topic of the Week","volume":"74","author":"Ternacle","year":"2019","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2210","DOI":"10.1016\/j.jaccas.2020.10.011","article-title":"Aortic Stenosis and Cardiac Amyloidosis: Watch out for Traps!","volume":"2","author":"Ternacle","year":"2020","journal-title":"JACC Case Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2329","DOI":"10.1016\/j.jacc.2013.08.1621","article-title":"The complex nature of discordant severe calcified aortic valve disease grading: New insights from combined Doppler echocardiographic and computed tomographic study","volume":"62","author":"Clavel","year":"2013","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"e011433","DOI":"10.1161\/CIRCIMAGING.120.011433","article-title":"Aortic Valve Calcium in Patients with Transthyretin Cardiac Amyloidosis: A Propensity-Matched Analysis","volume":"13","author":"Hussain","year":"2020","journal-title":"Circ. Cardiovasc. Imaging"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2205","DOI":"10.1016\/j.jaccas.2020.10.002","article-title":"Subthreshold Aortic Valve Calcium Scores in Severe Aortic Stenosis and Transthyretin Cardiac Amyloidosis","volume":"2","author":"Hussain","year":"2020","journal-title":"JACC Case Rep."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1016\/j.jcmg.2024.03.014","article-title":"Diagnostic Value of Aortic Valve Calcification Levels in the Assessment of Low-Gradient Aortic Stenosis","volume":"17","author":"Adrichem","year":"2024","journal-title":"JACC Cardiovasc. Imaging"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"201","DOI":"10.36628\/ijhf.2025.0052","article-title":"Clinical Applications of Speckle-Tracking Echocardiography in Heart Failure: From Diagnosis to Prognostication","volume":"7","author":"Lee","year":"2025","journal-title":"Int. J. Heart Fail."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"58","DOI":"10.36628\/ijhf.2026.0001","article-title":"Heart Failure Statistics 2025 Update: A Report from the Korean Society of Heart Failure","volume":"8","author":"Lee","year":"2026","journal-title":"Int. J. Heart Fail."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"287","DOI":"10.1093\/ehjci\/jeae276","article-title":"Prognostic and therapeutic implications of a low aortic valve calcium score in patients with low-gradient aortic stenosis","volume":"26","author":"Juhasz","year":"2025","journal-title":"Eur. Heart J. Cardiovasc. Imaging"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"e017870","DOI":"10.1161\/JAHA.120.017870","article-title":"Comparison of Early Surgical or Transcatheter Aortic Valve Replacement Versus Conservative Management in Low-Flow, Low-Gradient Aortic Stenosis Using Inverse Probability of Treatment Weighting: Results from the TOPAS Prospective Observational Cohort Study","volume":"9","author":"Annabi","year":"2020","journal-title":"J. Am. Heart Assoc."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1297","DOI":"10.1016\/j.jacc.2018.01.054","article-title":"Transcatheter Aortic Valve Replacement in Patients with Low-Flow, Low-Gradient Aortic Stenosis: The TOPAS-TAVI Registry","volume":"71","author":"Ribeiro","year":"2018","journal-title":"J. Am. Coll. Cardiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1001\/jamacardio.2018.4320","article-title":"Outcomes from Transcatheter Aortic Valve Replacement in Patients with Low-Flow, Low-Gradient Aortic Stenosis and Left Ventricular Ejection Fraction Less Than 30%: A Substudy from the TOPAS-TAVI Registry","volume":"4","author":"Maes","year":"2019","journal-title":"JAMA Cardiol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4795","DOI":"10.1093\/eurheartj\/ehaf362","article-title":"Cardiac transthyretin amyloidosis treatment improves outcomes after aortic valve replacement for severe stenosis","volume":"46","author":"Nitsche","year":"2025","journal-title":"Eur. Heart J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"ytaf471","DOI":"10.1093\/ehjcr\/ytaf471","article-title":"\u2018Masked apical sparing\u2019 in wild-type transthyretin cardiac amyloidosis complicated by aortic valve stenosis: A case report","volume":"9","author":"Matsumoto","year":"2025","journal-title":"Eur. Heart J. Case Rep."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"43","DOI":"10.36628\/ijhf.2025.0061","article-title":"Acute Heart Failure Across the Ejection Fraction Spectrum: Phenotypes, Management, and Outcomes from Nationwide KorHF III Registry","volume":"8","author":"Lee","year":"2026","journal-title":"Int. J. Heart Fail."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"139","DOI":"10.36628\/ijhf.2025.0037","article-title":"Establishing a National Quality of Care Framework for Heart Failure in Korea: Keep Standards for Heart Failure (KSHF) Initiative","volume":"7","author":"Jung","year":"2025","journal-title":"Int. J. Heart Fail."}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/14\/2177\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T04:13:29Z","timestamp":1784088809000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/16\/14\/2177"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,13]]},"references-count":20,"journal-issue":{"issue":"14","published-online":{"date-parts":[[2026,7]]}},"alternative-id":["diagnostics16142177"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics16142177","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,13]]}}}