Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Stenosis

Flavien Vincent, MD, PhD; Julien Ternacle, MD, PhD*; Tom Denimal, MD; Mylène Shen, MSc; Bjorn Redfors, MD, PhD; Cédric Delhaye, MD; Matheus Simonato, MD; Nicolas Debry, MD; Basile Verdier, MD; Bahira Shahim, MD, PhD; Thibault Pamart, MD; Hugues Spillemaeker, MD; Guillaume Schurtz, MD; François Pontana, MD, PhD; Vinod H. Thourani, MD; Philippe Pibarot, DVM, PhD; Eric Van Belle, MD, PhD

Disclosures

Circulation. 2021;143(10):1043-1061. 

In This Article

Abstract and Introduction

Abstract

After 15 years of successive randomized, controlled trials, indications for transcatheter aortic valve replacement (TAVR) are rapidly expanding. In the coming years, this procedure could become the first line treatment for patients with a symptomatic severe aortic stenosis and a tricuspid aortic valve anatomy. However, randomized, controlled trials have excluded bicuspid aortic valve (BAV), which is the most frequent congenital heart disease occurring in 1% to 2% of the total population and representing at least 25% of patients 80 years of age or older referred for aortic valve replacement. The use of a less invasive transcatheter therapy in this elderly population became rapidly attractive, and approximately 10% of patients currently undergoing TAVR have a BAV. The U.S. Food and Drug Administration and the "European Conformity" have approved TAVR for low-risk patients regardless of the aortic valve anatomy whereas international guidelines recommend surgical replacement in BAV populations. Given this progressive expansion of TAVR toward younger and lower-risk patients, heart teams are encountering BAV patients more frequently, while the ability of this therapy to treat such a challenging anatomy remains uncertain. This review will address the singularity of BAV anatomy and associated technical challenges for the TAVR procedure. We will examine and summarize available clinical evidence and highlight critical knowledge gaps regarding TAVR utilization in BAV patients. We will provide a comprehensive overview of the role of computed tomography scans in the diagnosis, and classification of BAV and TAVR procedure planning. Overall, we will offer an integrated framework for understanding the current role of TAVR in the treatment of bicuspid aortic stenosis and for guiding physicians in clinical decision-making.

Introduction

Initially designed as a new therapeutic option for inoperable patients with symptomatic severe aortic stenosis (AS),[1] the effectiveness of transcatheter aortic valve (AV) replacement (TAVR) has been confirmed through 15 years of successive randomized, controlled trials (RCTs). Transfemoral TAVR has demonstrated similar results or superiority over surgical AV replacement (SAVR) in low- to high-surgical risk elderly patients with tricuspid AV (TAV) stenosis.[2–5] Thus, TAVR is now the gold standard for patients at high surgical risk or deemed inoperable,[6] and is favored in patients at intermediate risk suitable for a transfemoral approach.[7] Conversely, the European Society of Cardiology guidelines recommend surgery (IIa/C) as the first line therapy for patients with severe AS and a bicuspid AV (BAV) anatomy[6] because these patients were excluded from previous RCTs. Thus, the efficacy and safety of TAVR are not well established in this population, while it is already frequently used. The balloon-expandable (BE) valve (SAPIEN-3) and self-expanding (SE) transcatheter heart valves (THVs) (Evolut-R/Pro) have received U.S. Food and Drug Administration and "European Conformity" approval for all surgical risk regardless of the valve anatomy and precaution regarding BAV, have recently been removed from commercial labeling.[8,9] Before being discontinued, the mechanical-expandable (ME) valve (Lotus Edge) was approved for high-risk patients regardless of the anatomy but with a precaution concerning the lack of data in BAV.[10]

This review aims to: (1) examine and summarize the currently available evidence for TAVR efficacy and identify the critical knowledge gaps; (2) address technical challenges of TAVR in BAV anatomy; (3) emphasize the role of computed tomography (CT) for BAV evaluation and TAVR procedure planning; and (5) offer an integrated framework for understanding the current role of TAVR in the treatment of bicuspid AS.

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