Valve Thrombosis Following Transcatheter Aortic Valve Replacement: State-of-the-Art Review.

Transcatheter aortic valve replacement (TAVR) is a well-established treatment for severe aortic stenosis, especially in patients over 75 or those at high surgical risk. While these prosthetic valves have a lower thrombogenic profile than mechanical heart valves, leaflet thrombosis in transcatheter aortic valves (TAV) occurs in an estimated 5%-40% of cases. Most TAV thromboses are subclinical and can be detected via cardiac computed tomography (CCT), which reveals hypo-attenuating leaflet thickening and reduced leaflet motion in asymptomatic patients without elevated transprosthetic gradients on echocardiography. The mechanisms behind TAV thrombosis involve local mechanical triggers, patient predisposing factors, and device and procedure-related aspects. The ideal antithrombotic therapy post-TAVR depends on individual patient characteristics, balancing bleeding risks with the need for oral anticoagulants. Data on the optimal management of TAV thrombosis and the routine use of CT post-TAVR are limited. While anticoagulation effectively resolves clinically significant prosthesis thrombosis, its benefit in subclinical cases is unclear. There is an ongoing debate about whether subclinical leaflet thrombosis precedes clinical valve thrombosis, making the ideal follow-up after valve implantation uncertain. This article aims to provide a comprehensive review, summarizing current data on the incidence of TAVR thrombosis, underlying mechanisms, clinical and imaging diagnosis, management strategies, preventive measures, and long-term follow-up.