ESC 2022: AI outshines sonographer echocardiogram assessment in EchoNet-RCT

David Ouyang

Results of one of the first and only randomised, blinded trials to assess the use of an artificial intelligence (AI) algorithm as an assessment tool for cardiac function suggest that AI improves evaluation when compared to assessment by a sonographer, attendees at the European Society of Cardiology (ESC) 2022 congress (26–29 August, Barcelona, Spain) have heard.

This was the message delivered by David Ouyang (Smidt Heart Institute at Cedars-Sinai, Los Angeles, USA) who presented findings from EchoNet-RCT, a blinded, randomised controlled trial involving a head-to-head comparison of sonographer and AI analysis of left ventricular ejection fraction (LVEF) in echocardiograms.

EchoNet-RCT was powered to show non-inferiority of the AI algorithm compared to sonographer tracings, but results presented by Ouyang showed that the AI demonstrated superiority with respect to the trial’s prespecified outcomes.

Echocardiography is an important cardiac diagnostic tool, Ouyang commented, though noted that one of its drawbacks is variability in interpretation. EchoNet-Dynamic is a deep learning algorithm that was trained on echocardiogram videos to assess cardiac function and was previously shown to assess LVEF with a mean absolute error of 4.1–6%. The algorithm uses information across multiple cardiac cycles to minimise error and produce consistent results.

EchoNet-RCT tested whether AI or sonographer assessment of LVEF is more frequently adjusted by a reviewing cardiologist. The standard clinical workflow for determining LVEF by echocardiography is that a sonographer scans the patient; the sonographer provides an initial assessment of LVEF; and then a cardiologist reviews the assessment to provide a final report of LVEF. In this clinical trial, the sonographer’s scan was randomly allocated 1:1 to AI initial assessment or sonographer initial assessment, after which blinded cardiologists reviewed the assessment and provided a final report of LVEF.

The researchers compared how much cardiologists changed the initial assessment by AI to how much they changed the initial assessment by sonographer. The primary endpoint was the frequency of a greater than 5% change in LVEF between the initial assessment (AI or sonographer) and the final cardiologist report. The trial was designed to test for non-inferiority, with a secondary objective of testing for superiority.

The study included 3,495 transthoracic echocardiograms performed on adults for any clinical indication. The proportion of studies substantially changed was 16.8% in the AI group and 27.2% in the sonographer group (difference -10.4%, 95% confidence interval [CI] -13.2% to -7.7%, p<0.001 for non-inferiority, p<0.001 for superiority). The safety endpoint was the difference between the final cardiologist report and a historical cardiologist report. The mean absolute difference was 6.29% in the AI group and 7.23% in the sonographer group (difference -0.96%, 95% CI -1.34% to -0.54%, p<0.001 for superiority).


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