{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T15:51:33Z","timestamp":1791215493700,"version":"4.1.0"},"reference-count":37,"publisher":"American Medical Association (AMA)","issue":"10","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA Netw Open"],"abstract":"\n Importance<\/jats:title>\n The optimal timing of mitral valve (MV) surgery in patients with asymptomatic severe primary mitral regurgitation (MR) remains uncertain because randomized clinical trials are lacking.<\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n To evaluate the association of early MV surgery with long-term survival in patients with asymptomatic severe primary MR using a target trial emulation framework.<\/jats:p>\n <\/jats:sec>\n \n Design, Setting, and Participants<\/jats:title>\n This cohort study used a clinical valve registry from 3 tertiary hospitals in South Korea between 2000 and 2022. Patients with asymptomatic severe primary MR were analyzed using a clone-censor-weight approach to emulate a target trial. A 6-month grace period after diagnosis was used to define treatment strategies. This analysis was conducted from September 2024 to January 2025.<\/jats:p>\n <\/jats:sec>\n \n Exposure<\/jats:title>\n Early MV surgery (within 6 months of diagnosis) vs watchful waiting.<\/jats:p>\n <\/jats:sec>\n \n Main Outcomes and Measures<\/jats:title>\n The primary outcome was all-cause mortality and the secondary outcome, a composite of all-cause mortality or heart failure hospitalization. Inverse probability of censoring-weighted estimates of the per-protocol effect size included restricted mean survival time (RMST) differences as the primary measure and hazard ratios (HRs) as secondary measures.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n Among 802 patients (mean [SD] age, 55 [16] years; 476 men [59%]), 344 underwent early surgery, and 458 received watchful waiting. During a median (IQR) follow-up of 7.4 (4.1-11.6) years, 27 deaths occurred in the early surgery group and 103 in the watchful waiting group. At 5 years, early surgery was associated with an RMST gain of 66 days (95% CI, 19-129 days). The survival benefit persisted up to 15 years. Early surgery was also associated with a lower risk of all-cause mortality compared with watchful waiting (HR, 0.69; 95% CI, 0.41-0.94;\n P<\/jats:italic>\n \u2009=\u2009.02). Similar associations were observed in patients without left ventricular decompensation (HR, 0.61; 95% CI, 0.31-0.96;\n P<\/jats:italic>\n \u2009=\u2009.04) and in those with degenerative MR (HR, 0.66; 95% CI, 0.36-0.98;\n P<\/jats:italic>\n \u2009=\u2009.04).\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions and Relevance<\/jats:title>\n In this multicenter cohort study with a target trial framework, early surgery was associated with improved long-term survival among patients with asymptomatic severe primary MR. These findings support consideration of earlier surgical intervention in contemporary clinical practice.<\/jats:p>\n <\/jats:sec>","DOI":"10.1001\/jamanetworkopen.2026.37061","type":"journal-article","created":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T15:00:26Z","timestamp":1791212426000},"page":"e2637061","source":"Crossref","is-referenced-by-count":0,"title":["Early Mitral Valve Surgery and Survival in Asymptomatic Severe Primary Mitral Regurgitation"],"prefix":"10.1001","volume":"9","author":[{"given":"Juhee","family":"Ahn","sequence":"first","affiliation":[{"name":"Division of Data Science, University of Suwon, Hwaseong, Republic of Korea"},{"name":"Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Soongu","family":"Kwak","sequence":"additional","affiliation":[{"name":"Division of Cardiology and Cardiovascular Center, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jaehyun","family":"Lim","sequence":"additional","affiliation":[{"name":"Division of Cardiology and Cardiovascular Center, Department of Internal Medicine, Seoul National University Hospital, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kyu","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jihoon","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Heart Vascular Stroke Institute, Sungkyunkwan University School of Medicine and Samsung Medical Centre, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Byung Joo","family":"Sun","sequence":"additional","affiliation":[{"name":"Division of Cardiology, College of Medicine, University of Ulsan and Asan Medical Centre, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dae-Hee","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Cardiology, College of Medicine, University of Ulsan and Asan Medical Centre, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kyung Hwan","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital, Seoul, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chi Young","family":"Shim","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sung-Ji","family":"Park","sequence":"additional","affiliation":[{"name":"Division of Cardiology, Heart Vascular Stroke Institute, Sungkyunkwan University School of Medicine and Samsung Medical Centre, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sungho","family":"Won","sequence":"additional","affiliation":[{"name":"Institute of Health and Environment, Seoul National University, Seoul, Republic of Korea"},{"name":"Department of Public Health Sciences, Seoul National University, Seoul, Republic of Korea"},{"name":"Interdisciplinary Program of Bioinformatics, Seoul National University, Seoul, Republic of Korea"},{"name":"RexSoft Inc, Seoul, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seung-Pyo","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Cardiology and Cardiovascular Center, Department of Internal 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