Subclinical valve thrombosis in transcatheter aortic valve implantation: A systematic review and meta-analysis

Recent high-resolution computed tomography studies after transcatheter aortic valve insertion (TAVI) have reported a high prevalence of subclinical valve thrombosis (SCVT), potentially contributing to increased risk of late stroke. We aimed to investigate SCVT in patients after TAVI, with a focus on prevalence, predisposing factors, management, and potential sequelae.

A comprehensive literature review of patients with SCVT after TAVI was carried out on all published studies in 3 major electronic databases from their inception until October 2019. Studies with sufficient data were included in a meta-analysis comparing the risk of stroke between patients with SCVT and those with normal valve function, as well as the protective effects of antiplatelet and anticoagulation on preventing SCVT.

From 3456 patients examined in a comprehensive review, 398 patients (11.5%) demonstrated evidence of SCVT during follow-up. Dual antiplatelet therapy was given in 45.5% of cases, single antiplatelet therapy in 19.8%, and oral anticoagulation in 28.5%. A meta-analysis demonstrated that rates of stroke were more than 3 times greater in patients with SCVT compared with those without (logistic odds, 1.10; 95% confidence interval, 0.63-1.57, P < .0001). Oral anticoagulation was superior to dual antiplatelet therapy or single antiplatelet therapy, preventing the formation of SCVT (logistic odds, -1.05, 95% confidence interval, -1.71 to -0.39, P < .0001).

Subclinical valve thrombosis is seen in 11.5% of patients after TAVI and is associated with increased risk of stroke. When oral anticoagulation is used postprocedurally, it is more effective than either dual or single-antiplatelet therapy in preventing subclinical valve thrombosis. These findings suggest that further studies are needed to define the optimal antithrombotic regimen to mitigate thrombotic and embolic sequelae after TAVI.