[Transcatheter aortic valve thrombosis]

Transcatheter aortic valve or leaflets thrombosis are mainly misapprehended. It negatively impacts the long-term efficiency of such prosthesis. Moreover, its incidence is presumably higher than previously described.

Recently reported subclinical leaflet thrombosis, occurring between first to third months after implantation, is about 10to 15%. All prosthesis are concerned by potential thrombosis.

Transcatheter aortic valve thrombosis is usually detected on the basis of increased transvalvular pressure gradients or symptoms at routine follow-up. Main causes of post-TAVI thrombosis are: elderly patients, incomplete TAVI expansion, incomplete TAVI apposition to the aortic wall, areas of diminished blood flow and stagnation around the prosthesis. Main risk-factors of thrombosis are: large valves, patients with ejection fraction lower than 35%, valve-in-valve implantation, males, patients with large sinus of Valsalva, patients without anticoagulants.

Post-TAVI anti thrombotic regimen remains empirical. It is based on aspirin alone or dual antiplatelet therapy for 1-6months, followed by aspirin for life. Symptomatic patients with thrombus-based valve dysfunction are to be treated by oral anticoagulation (i.e., VKA or new oral anticoagulants NOAC). This treatment allows the restoration of normal leaflet motion in patients with a median time of 14 days.