Early surgery outperforms conservative management in asymptomatic severe aortic stenosis

The AVATAR trial demonstrated benefits of early surgical aortic valve replacement compared with conservative management in patients with asymptomatic severe aortic stenosis with a normal left ventricular function. These results show that surgery is indicated when aortic stenosis is significant, albeit asymptomatic [1].

A recent randomised trial suggested that early surgery outperforms conservative management in a population of patients with very severe aortic stenosis [2]. However, surgery in asymptomatic patients with severe aortic stenosis remained a topic of debate. Thus, the prospective, multicentre, randomised, open-label AVATAR study (NCT02436655) assessed the efficacy and safety of early surgical valve replacement in a population of patients with asymptomatic severe aortic stenosis with a normal left ventricular function. Eligible patients underwent a mandatory exercise test to control for the onset of aortic stenosis-related symptoms. The primary endpoint was the incidence of major adverse cardiac events (MACE). The event-driven design targeted 35 events for the analysis. Prof. Marko Banovic (University Clinical Centre of Serbia, Serbia) presented the findings of the study.

The pre-specified number of events was achieved at a median follow-up of 32 months, with 157 patients randomised 1:1 to the early surgery arm or the conservative management arm. Participants in the early surgery arm demonstrated fewer MACE events (13 events) than participants in the conservative management arm (26 events). A log-rank test showed a corresponding hazard ratio of 0.46 (P=0.021) over 48 months for the primary endpoint (see Figure).

Figure: 48-week trajectory of cardiovascular events [1]



In addition, a numerical advantage of early surgery over conservative treatment was displayed for all-cause death (HR 0.56; P=0.16) and heart failure hospitalisation (HR 0.32; P=0.075). A composite endpoint of all-cause death and heart failure hospitalisation, conducted post-hoc, showed significant benefits of early surgery over watchful waiting (HR 0.40; 0.013). The intraoperative mortality rate in the early surgery arm (1.4%) did not exceed the expectations of the authors, according to Dr Banovic.

The results of the AVATAR trial are consistent with the findings of Kang et al. [2]. However, long-term follow-up is required to assess potential safety issues, such as valve durability, endocarditis, and thromboembolic complications.

 

1. 
   
   1. Banovic M, et al. Aortic Valve Replacement versus Watchful Waiting in Asymptomatic Severe Aortic Stenosis: The Avatar Trial. LBS01, AHA Scientific Sessions 2021, 13–15 November.
   2. Kang DH, et al. N Engl J Med 2020;382:111–119.

 

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Posted on 14 January 202214 January 2022