Leaflet Immobility and Thrombosis in Transcatheter Aortic Valve Replacement

Arnold C. T. Ng; David R. Holmes; Michael J. Mack; Victoria Delgado; Raj Makkar; Philipp Blanke; Jonathon A. Leipsic; Martin B. Leon; Jeroen J. Bax

Disclosures

Eur Heart J. 2020;41(33):3184-3197. 

In This Article

Abstract and Introduction

Abstract

Transcatheter aortic valve replacement (TAVR) has grown exponentially worldwide in the last decade. Due to the higher bleeding risks associated with oral anticoagulation and in patients undergoing TAVR, antiplatelet therapy is currently considered first-line antithrombotic treatment after TAVR. Recent studies suggest that some patients can develop subclinical transcatheter heart valve (THV) thrombosis after the procedure, whereby thrombus forms on the leaflets that can be a precursor to leaflet dysfunction. Compared with echocardiography, multidetector computed tomography is more sensitive at detecting THV thrombosis. Transcatheter heart valve thrombosis can occur while on dual antiplatelet therapy with aspirin and thienopyridine but significantly less with anticoagulation. This review summarizes the incidence and diagnostic criteria for THV thrombosis and discusses the pathophysiological mechanisms that may lead to thrombus formation, its natural history, potential clinical implications and treatment for these patients.

Graphical Abstract

Introduction

The use of bioprosthetic aortic valves as compared with mechanical valves has been the dominant strategy for the treatment of aortic stenosis in elderly patients. Worldwide, transcatheter aortic valve replacement (TAVR) has replaced surgical aortic valve replacement (SAVR) as the treatment of choice for high-risk patients and is increasingly utilized in lower-risk patients. Recent data suggested that TAVR for intermediate- and low-risk aortic stenosis patients was associated with significantly lower stroke and mortality risk at 1 year compared with SAVR.[1,2] Furthermore, there is preliminary evidence for survival benefit in early TAVR for asymptomatic patients with very severe aortic stenosis.[3] Accordingly, it is likely that TAVR will be increasingly utilized in the future.

However, subclinical transcatheter heart valve (THV) thrombosis (usually referring to thrombus formation on the valve leaflets) following TAVR is increasingly recognized in patients who undergo routine four-dimensional (4D) multidetector computed tomography (MDCT) post-procedure. This review aims to determine the incidence of THV thrombosis, identify potential pathogenesis, summarize the imaging diagnostic criteria, and explore potential clinical implications and management strategies for patients.

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