Aortic Valve Replacement Versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis: The AVATAR Trial

Abstract

Background: Surgical aortic valve replacement (SAVR) represents a class I indication in symptomatic patients with severe aortic stenosis (AS). However, indications for early SAVR in asymptomatic patients with severe AS and normal left ventricular function remain debated. Methods: The Aortic Valve replAcemenT versus conservative treatment in Asymptomatic seveRe aortic stenosis (AVATAR) trial is an investigator-initiated international prospective randomized controlled trial that evaluated the safety and efficacy of early SAVR in the treatment of asymptomatic patients with severe AS, according to common criteria (valve area ≤1 cm 2 with aortic jet velocity >4 m/s or a mean trans-aortic gradient ≥40 mm Hg), and with normal LV function. Negative exercise testing was mandatory for inclusion. The primary hypothesis was that early SAVR would reduce the primary composite endpoint of all-cause death, acute myocardial infarction, stroke or unplanned hospitalization for heart failure, as compared to a conservative strategy according to guidelines. The trial was designed as event-driven to reach a minimum of 35 prespecified events. The study was performed in 9 centers in 7 European countries. Results: Between June 2015 and September 2020, 157 patients (mean age 67 years, 57 % men) were randomly allocated to early surgery (n=78) or conservative treatment (n=79). Follow-up was completed in May 2021. Overall median follow-up was 32 months: 28 months in the early surgery group and 35 months in the conservative treatment group. There was a total of 39 events, 13 in early surgery and 26 in conservative treatment group. In the early surgery group, 72 patients (92.3 %) underwent SAVR with operative mortality of 1.4 %. In an intention-to-treat analysis, patients randomized to early surgery had a significantly lower incidence of primary composite endpoint than those in the conservative arm (HR 0.46, 95 % CI 0.23-0.90, p=0.02). There was no statistical difference in secondary endpoints, including all-cause mortality, first heart failure hospitalizations, major bleeding or thromboembolic complications, but trends were consistent with the primary outcome. Conclusions: In asymptomatic patients with severe AS, early surgery reduced a primary composite of all-cause death, acute myocardial infarction, stroke or unplanned hospitalization for heart failure compared with conservative treatment. This randomized trial provides preliminary support for early SAVR once AS becomes severe, regardless of symptoms.

Challenges in Diagnosis and Functional Assessment of Coronary Artery Disease in Patients With Severe Aortic Stenosis

“…In recent years, published large randomized trials and meta-analyses demonstrated non-inferiority and even superiority concerning major adverse cardiac events (MACE) favoring TAVR over SAVR across the spectrum of AS-patients, irrespective of baseline surgical risk ( 20 – 24 ). In addition, recently presented the Aortic Valve ReplAcemenT vs. Conservative Treatment in Asymptomatic SeveRe Aortic Stenosis (AVATAR) randomized trial demonstrated benefit of early SAVR in asymptomatic patients with severe AS and normal LV ejection fraction ( 25 ). Expert consensus opinion (class IIa, level of evidence C) highlights that percutaneous coronary intervention (PCI) should be considered in AS-patients with a primary indication to undergo TAVR who have stenosis of at least 70% DS in the proximal segments of epicardial coronary arteries that subtend a large area of myocardium at risk ( 7 , 10 ).…”

Predictors of Mortality Following Aortic Valve Replacement in Aortic Stenosis Patients

“…It is also known that surgery should be considered in asymptomatic patients and in patients with aortic stenosis at earlier stages in order to reduce the risk of surgical intervention. The use of echocardiography capabilities is an effective strategy in this cohort of patients [ 15 , 16 ].…”

Hemodynamic Performance of Sutureless vs. Conventional Bioprostheses for Aortic Valve Replacement: The 1-Year Core-Lab Results of the Randomized PERSIST-AVR Trial

“…The early recognition and management of this pathology are very important because untreated asymptomatic and symptomatic severe diseases result in poor outcomes if managed with conservative treatment. In these patients, therefore, aortic valve replacement (AVR) represents the treatment of choice (1)(2)(3)(4). New prostheses have been developed to minimize the surgical risk in patients with multiple comorbidities and to reduce operating times.…”