Bioprosthetic leaflet thrombosis and reduced leaflet motion after transcatheter aortic valve replacement: A systematic review and meta-analysis.

Background: Leaflet thrombosis and reduced leaflet motion have become a concern with the expanding use of transcatheter aortic valve replacement in lower-risk patients.

Aims: To assess the proportions, predictors and clinical impact of leaflet thrombosis and reduced leaflet motion after transcatheter aortic valve replacement.

Methods: We performed a meta-analysis of studies assessing the proportions of and/or clinical outcomes according to the presence of leaflet thrombosis after transcatheter aortic valve replacement identified with computed tomography and/or echocardiography.

Results: Fifty-three studies, representing 25,258 patients undergoing transcatheter aortic valve replacement, were considered. The proportion of leaflet thrombosis was 5.2% overall, and was higher in computed tomography versus echocardiography (16.4% vs. 1.1%, respectively); reduced leaflet motion was identified in 11% of patients with four-dimensional computed tomography. Intra-annular bioprostheses were associated with a higher proportion of leaflet thrombosis, whereas chronic oral anticoagulation was protective for leaflet thrombosis in both computed tomography and echocardiographic studies (9.7% vs. 17.5%; relative risk [RR]: 0.51, 95% confidence interval [95% CI]: 0.37-0.71 and 0.9% vs. 2.7%; RR: 0.22, 95% CI: 0.06-0.79, respectively) and for reduced leaflet motion (2.5% vs. 12.4%; RR: 0.32, 95% CI: 0.13-0.76). Leaflet thrombosis was not associated with an increased risk of death, but with a higher risk of stroke in computed tomography studies (2.8% vs. 2.4%; RR: 1.63, 95% CI: 1.05-2.55), a difference more pronounced when considering reduced leaflet motion (3.5% vs. 1.7%; RR: 2.39, 95% CI: 0.63-8.34).

Conclusions: The proportion of leaflet thrombosis is highly variable according to the screening approach, the type of valve and the use of oral anticoagulation. The occurrence of cerebral events is increased when leaflet thrombosis and/or reduced leaflet motion are diagnosed, but leaflet thrombosis has no impact on survival.