The optimal management of anti-thrombotic therapy after valve replacement: certainties and uncertainties.

Anti-thrombotic therapy after valve replacement encompasses a number of different situations. Long-term anticoagulation of mechanical prostheses uses vitamin K antagonists with a target international normalized ratio adapted to the characteristics of the prosthesis and the patient. The association of low-dose aspirin is systematic in the American guidelines and more restrictive in the European guidelines. Early heparin therapy is frequently used early after mechanical valve replacement, although there are no precise recommendations regarding timing, type, and dose of drug. Direct oral anticoagulants are presently contraindicated in patients with mechanical prosthesis. The main advantage of bioprostheses is the absence of long-term anticoagulant therapy. Early anticoagulation is indicated after valve replacement for mitral bioprostheses, whereas aspirin is now favoured early after bioprosthetic valve replacement in the aortic position. Early dual antiplatelet therapy is indicated after transcatheter aortic valve implantation, followed by single antiplatelet therapy. However, this relies on low levels of evidence and optimization of anti-thrombotic therapy is warranted in these high-risk patients. Although guidelines are consistent in most instances, discrepancies and the low-level of evidence of certain recommendations highlight the need for further controlled trials, in particular with regard to the combination of antiplatelet therapy with oral anticoagulant and the early post-operative anti-thrombotic therapy following the procedure.