Subclinical leaflet thrombus in patients with severe aortic stenosis and atrial fibrillation -ENRICH-AF TAVI study

Abstract

Subclinical leaflet thrombosis (SLT) can be one of the causes of transcatheter heart valve (THV) failure after transcatheter aortic valve implantation (TAVI). We sought to clarify the formation process of SLT and thrombogenicity during the perioperative period of TAVI. This multicenter, prospective, single-arm interventional study enrolled 26 patients treated with edoxaban for atrial fibrillation and who underwent TAVI for severe aortic stenosis between September 2018 and September 2022. We investigated changes in maximal leaflet thickness detected by contrast-enhanced computed tomography between 1 week and 3 months after TAVI in 18 patients and measured the thrombogenicity by Total Thrombus-formation Analysis System (T-TAS) and flow stagnation volume by computational fluid dynamics (CFD) (n = 11). SLT was observed in 16.7% (3/18) at 1 week, but decreased to 5.9% (1/17) at 3 months after TAVI. Patients with SLT at 1 week had a significantly decreased maximal leaflet thickness compared to those without SLT. Thrombogenicity assessed by T-TAS decreased markedly at 1 week and tended to increase at 3 months. The stagnation volume assessed by CFD was positively associated with a higher maximum leaflet thickness. This study showed the course of leaflet thrombus formation and visualization of stagnation in neo-sinus of THV in the acute phase after TAVI.

Keywords: CFD; DOAC; Leaflet thrombosis; T-TAS; TAVI.

Figure 1

Difference in maximum leaflet thickness between 1 week and 3 months after TAVI stratified by leaflet thrombus. Maximum leaflet thickness was measured in 18 patients at 1 week and 17 at 3 months after TAVI (A). Box-and-whisker plot shows the increase in maximal leaflet thickness from 1 week to 3 months CT after TAVI (B). Table shows summary statistics of the maximal leaflet thickness at 1 week, 3 months, and the difference according to the presence of the leaflet thrombosis at 1 week after TAVI (C).

Figure 2

Changes in thrombogenicity parameters. These box-and whisker plots and each data point show sequential changes in AR-AUC (A), PL-AUC (B), and platelet count (C) before (n = 25) and at 1 week (n = 21) and 3 months (n = 18) after TAVI. AR-AUC indicates area under the curve for the atheroma chip; TAVI, transcatheter aortic valve implantation; PL-AUC, area under the curve for the platelet chip.

Figure 3

Difference in flow stagnation between patients with and without leaflet thrombus. Box-and-whisker plots show the difference in mean stagnation volume at systolic (A) and diastolic phase (B) between patients with and without leaflet thrombus at 1 week after TAVI.