Title: Acute valve malfunction with thrombosed bioprosthetic valve after surgical aortic valve replacementAuthor name: Hiroki Moriuchi, Masaaki Koide, Yoshifumi Kunii, Takuya Maeda, Risa ShimboriAffiliations: SeireiHamamatsu Hospotal, Department of cardiovascular surgeryKey words: thrombus, bioprosthetic aortic valveCorresponding author’s address: 2-12-12, Sumiyoshi, Nakaku, Hamamatsu, Shizuoka, JapanEmail: porimori22@gmail.comAUTHOR CONTRIBUTIONSMasaaki Koide and Takuya Maeda involved in review and editing.ACKNOWLEDGEMENTSI appreciate Mr. Andrew for reviewing manuscript and Yuki Moriuchi for total support.FUNDING INFORMATIONNoneCONFLICT OF INTEREST STATEMENTThe authors report no conflict of interest.DATA AVAILABILITY STATEMENTNoneCONSENT STATEMENTWritten informed consent was obtained from the patient to publish this report in accordance with the journal’s patient consent policy.CASE PRESENTATIONA 74-year-old man with chest pain was diagnosed with Stanford A acute aortic dissection and severe aortic regurgitation. Aortic valve replacement with a 21mm INSPIRIS (Edwards Lifesciences, Irvine, CA, USA) and ascending aortic replacement with 26mm J Graft (Japan Lifeline, Tokyo) was performed. Anticoagulation therapy using heparin and warfarin was started immediately. Postoperative Computed tomography(CT) revealed thrombus formation to all leaflets of the implanted valve(Figure1) and echocardiography revealed restricted leaflet motion, so surgical thrombectomy was performed. Abundant fresh thrombi adhered to all leaflets of the bioprosthetic valve, and those thrombi were carefully removed (Figure2). No damage or macroscopic degeneration on the leaflets were seen, so the implanted valve was preserved. We initiated argatoroban for 1 week, followed by aspirin and warfarin and postoperative CT showed no sign of thrombus. (Figure 3).We previously reported leaflet and coronary stent thrombosis after TAVR2, but acute bioprosthetic valve thrombosis after SAVR is extremely rare.1 Reference1. Cahill TJ, Khalique OK, Geourge Im et al. Valve thrombosis after transcatheter and surgical aortic valve replacement: Incidence and outcomes. J Thorac Cardiovasc Surg. 2022 Apr;163(4):1309-1315.2. Satoshi O, Masaaki K, Yoshifumi K, et al. Leaflet and coronary stent thrombosis after transcatheter aortic valve implantation treated by aortic valve replacement. Eur Heart J Cardiovasc Imaging. 2020 Mar 1;21(3):347Figure legendsFigure1: Computed tomography(CT) shows thrombi in all leafletsFigure2: All thrombi were removed completelyFigure3: Postoperative CT shows no thrombus in bioprosthetic aortic valveKey Clinical MessageAcute valve thrombosis after bioprosthetic aortic valve replacement even under appropriate anticoagulation therapy is extremely rare. Cardiac CT is a powerful imaging tool to detect valve thrombosis after both TAVR and SAVR.