ObjectivesThere is a lack of high-quality data informing the optimal antithrombotic drug strategy following bioprosthetic heart valve replacement or valve repair. Disparity in recommendations from international guidelines reflects this. This study aimed to document current patterns of antithrombotic prescribing after heart valve surgery in the United Kingdom.MethodsAll UK consultant cardiac surgeons were e-mailed a custom-designed survey. The use of oral anticoagulant (OAC) and/or antiplatelet drugs following bioprosthetic aortic (AVR) or mitral valve replacement (MVR), or mitral valve repair (MVrep), for patients in sinus rhythm, without additional indications for antithrombotic medication, was assessed. Additionally, we evaluated anticoagulant choice following MVrep in patients with atrial fibrillation (AF).ResultsWe identified 260 UK consultant cardiac surgeons from 36 units, of whom 103 (40%) responded, with 33 units (92%) having at least one respondent. The greatest consensus was for patients undergoing bioprosthetic AVR, in which 76% of surgeons favour initial antiplatelet therapy and 53% prescribe lifelong treatment. Only 8% recommend initial OAC. After bioprosthetic MVR, 48% of surgeons use an initial OAC strategy (versus 42% antiplatelet), with 66% subsequently prescribing lifelong antiplatelet therapy. After MVrep, recommendations were lifelong antiplatelet agent alone (34%) or following 3 months OAC (20%), no antithrombotic agent (20%), or 3 months OAC (16%). After MVrep for patients with established AF, surgeons recommend warfarin (38%), a direct oral anticoagulant (37%) or have no preference between the two (25%).ConclusionThere is considerable variation in the use of antithrombotic drugs after heart valve surgery in the UK. This reflects the lack of high-quality evidence and underscores the need for randomised studies.KEY MESSAGESWhat is already known on this topic?The most appropriate antithrombotic drug regime following bioprosthetic heart valve replacement or mitral valve repair is not known. Contemporary practice in the UK has not been established.What this study addsThis study demonstrates wide variation in antithrombotic drug choice and duration following bioprosthetic heart valve replacement or mitral valve repair in the UK.How this study might affect research, practice, or policyRandomised studies are required to assess the most appropriate antithrombotic strategy after heart valve surgery.