Cautious Optimism Regarding Early Transcatheter Aortic Valve Replacement

Abstract

Leonardo da Vinci provided his first drawing of the aortic valve 5 centuries ago, and by the following century Lazare Riviere first described pathologic aortic valve stenosis in the “Opera Medica Universa.” Although it took another 300 years until Harken first implanted an aortic valve prosthetic in the proper anatomical position in 1966, there has been rapid evolution in aortic valve care during the past 5 decades. The remainder of the 20th century saw important improvements in surgical techniques and valve design, and the 21st century brought a revolution to this space with the first human transcatheter aortic valve replacement (TAVR) placed by Cribier in 2002. During the past 2 decades, there has been an unprecedented degree of technologic innovation in the field and randomized trial data confirming TAVR as a safe and effective treatment option for anatomically feasible patients with severe aortic stenosis (AS) across all surgical risk groups. Without question, the roll out of TAVR has been methodical and data driven. Approval of the earlygeneration devices was provided only after randomized trials confirmed efficacy and safety in patients considered either inoperable or at high surgical risk.1,2 Expansion of the therapeutic indication to include intermediate and low surgical risk patients followed after subsequent trials randomly assigned patients to either the surgical standard or TAVR and confirmed the safety and efficacy among these groups. Accordingly, TAVR treatment is now available in 715 US TAVR centers (as of August 2020). Although the focus of these trials has been the treatment of patients with symptomatic severe AS, we have begun to question whether there is a benefit to treating patients with AS at an earlier stage. At the time of diagnosis, up to onehalf of the patients with severe AS fit the definition of “asymptomatic.” The idea that timely intervention can prevent irreversible damage to the heart (including left ventricle [LV] hypertrophy, left atrium [LA] enlargement, and eventual LV dysfunction) combined with the safety and minimally invasive nature of the procedure have raised the question of earlier intervention in the course of AS.3 The treatment of asymptomatic severe AS is the focus of a number of randomized controlled trials. AVATAR (Aortic Valve Replacement Versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis) and RECOVERY (Randomized Comparison of Early Surgery Versus Conventional Treatment in Very Severe Aortic Stenosis [NCT01161732]) were designed to understand whether early surgical intervention might be beneficial rather than ongoing monitoring.3 In this regard, both trials have shown early surgical aortic valve replacement (SAVR) to be beneficial in terms of allcause mortality and newonset heart failure compared with conservative management.3 However, the small number of included patients with variable followup limits the extension of these findings. Nevertheless, the findings are thought provoking, especially when one considers the less invasive option of TAVR. In this regard, the Evaluation of TAVR Compared to Surveillance for Patients With Asymptomatic Severe Aortic Stenosis (NCT03042104) study using the balloonexpandable SAPIEN3 prosthetic (Edwards Lifesciences, Irvine,