Abstract
Transcatheter aortic valve replacement (TAVR) has become an established therapeutic option for patients with symptomatic, severe aortic valve stenosis at increased surgical risk. Antithrombotic therapy after TAVR aims to prevent transcatheter heart valve (THV) thrombosis, in which two different entities have to be recognized: clinical valve thrombosis and subclinical leaflet thrombosis. In clinical valve thrombosis, obstructive thrombus formation leads to an increased transvalvular gradient, often provoking heart failure symptoms. Subclinical leaflet thrombosis is most often an incidental finding, characterized by a thin layer of thrombus covering the aortic side of one or more leaflets; it is also referred to as Hypo-Attenuating Leaflet Thickening (HALT) as described on multi-detector computed tomography (MDCT) imaging. This phenomenon may also affect leaflet motion and is then classified as Hypo-Attenuation affecting Motion (HAM). Even in case of HAM, the transvalvular pressure gradient remains within normal range and does not provoke heart failure symptoms. Whereas, clinical valve thrombosis requires treatment, the clinical impact and need for intervention in subclinical leaflet thrombosis is still uncertain. Oral anticoagulant therapy protects against and resolves both clinical valve thrombosis and subclinical leaflet thrombosis; however, large-scale randomized clinical trials studying different antithrombotic strategies after TAVR are still under way. This review article summarizes the currently available data within the field of transcatheter aortic valve/leaflet thrombosis and discusses the need for a patient tailored antithrombotic approach.
Highlights
Transcatheter aortic valve replacement (TAVR) has become an established therapeutic option for patients with symptomatic, severe aortic valve stenosis who are at increased surgical risk
This review aims to summarize and discuss currently available data on clinical valve thrombosis and subclinical leaflet thrombosis in transcatheter aortic bioprosthesis with additional focus on a patient-tailored antithrombotic approach
A recent retrospective analysis showed that absence of oral anticoagulant (OAC) was independently associated with an increase in transvalvular gradient at long-term follow-up [32]. The fact that this phenomenon is a dynamic process makes it hard to investigate its possible impact on long-term durability. This assumption is not supported by mid-term data demonstrating transcatheter heart valve (THV) durability to be non-inferior as compared to surgical bioprosthetic valves, subclinical leaflet thrombosis occurs more frequent after TAVR than after surgical aortic valve replacement (SAVR) [29, 30, 33]
Summary
Transcatheter aortic valve replacement (TAVR) has become an established therapeutic option for patients with symptomatic, severe aortic valve stenosis who are at increased surgical risk.
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