Abstract 12293: Subclinical Leaflet Thrombus on Transcatheter Heart Valve in Patients With Severe Aortic Stenosis and Atrial Fibrillation

Abstract

Background: Subclinical leaflet thrombosis is one of transcatheter heart valve (THV) failure that should be avoided after transcatheter aortic valve implantation (TAVI). Although the effectiveness of direct oral anticoagulants (DOACs) on subclinical leaflet thrombosis has been demonstrated, there is insufficiently established evidence for post-TAVI antithrombotic therapy. The aim of this study was to clarify the formation process of subclinical leaflet thrombosis on THV and thrombogenicity during the perioperative period of TAVI. Methods: This multicenter, prospective, single-arm interventional study enrolled 26 patients with atrial fibrillation treated with edoxaban and severe aortic valve stenosis who underwent TAVI between September 2018 and September 2022. After exclusion, 24 patients were finally analyzed. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD). Results: Of all, subclinical leaflet thrombosis was observed in 16.7% at 1 week, but decreased to 5.9% at 3 months after TAVI. There was no significant difference in maximum leaflet thickness between 1 week and 3 months, however, patients with subclinical leaflet thrombosis at 1 week had a significantly greater difference in that thickness compared to those without thrombosis. Thrombogenicity assessed by T-TAS and platelet count decreased markedly at 1 week and tended to improve at 3 months. Simple liner regression analysis showed that stagnation volume was positively associated with an increase in maximum leaflet thickness, and low-dose edoxaban was associated with a high risk of increased leaflet thickness at chronic phase. Conclusions: This study showed that course of leaflet thrombus formation in neo-sinus of THV and dynamic fluctuation of thrombogenicity in the acute phase after TAVI. These findings were merely hypotheses generation and thus necessitate future hypothesis testing with large sample sizes.