Subclinical leaflet thrombosis after transcatheter aortic valve implantation

Although clinically significant valve thrombosis after transcatheter aortic valve implantation (TAVI) is rare, the incidence of subclinical leaflet thrombosis has been reported to be up to about 10%-15%. It is mostly found 1-3 months after procedure in any type of transcatheter heart valve. Leaflet thrombosis is detected by high-resolution CT in the form of limited valve opening/closure and hypoattenuated leaflet thickening. Transthoracic or transesophageal echocardiography is capable of detecting limitations of valve motion, leaflet thickening, increased flow velocity across the valve. However, CT seems to be more sensitive than echocardiography to detect leaflet thrombosis. It can occur under dual antiplatelet therapy with aspirin and a thienopyridine but rarely occurs with anticoagulation with a vitamin K antagonist. A vitamin K antagonist is also helpful to resolve leaflet thrombosis. Several studies are ongoing to determine the effect of new oral anticoagulants (NOACs) in preventing major cardiovascular events. They will also provide useful information on whether NOACs prevent leaflet thrombosis.