Core Laboratory Versus Center-Reported Echocardiographic Assessment of the Native and Bioprosthetic Aortic Valve

Insights into quantitative differences between core laboratory and center-reported echocardiographic assessment of the native and bioprosthetic aortic valve are lacking. We aimed to explore clinically relevant differences between these evaluations.

Data were used from the PERIcardial SurGical AOrtic Valve ReplacemeNt (PERIGON) Pivotal Trial for the Avalus valve. In this trial, patients with an indication for surgical aortic valve replacement (SAVR) due to aortic stenosis or regurgitation (AR) were enrolled. Serial echocardiographic examinations were performed at each center and blindly reanalyzed by an independent echocardiographic core laboratory (ECL). For the bioprosthetic valve analysis, postoperative data throughout the 5-year follow-up were pooled. Differences between the ECL and the centers in continuous parameters were quantified in mean differences and intraclass correlation coefficients (ICCs). Agreement on AR, paravalvular leak (PVL), and prosthesis-patient mismatch (PPM) classification was investigated using Cohen's kappa coefficients.

The analysis on the native aortic valve was performed on 1118 echocardiograms. The relative mean difference was largest for the left ventricular outflow tract (LVOT) area, followed by stroke volume and effective orifice area (index), with center-reported values being 11%-7% higher. High ICCs of around 0.90 were observed for the parameters peak aortic jet velocity, mean pressure gradient, and the velocity-time integral across the aortic valve. Over 5000 echocardiograms were available for the bioprosthetic valve analysis. Therein, comparable results were observed. The kappa coefficient was 0.59 (95% confidence interval [CI] 0.56, 0.63) for agreement on native AR, 0.28 (95% CI 0.18, 0.37) for PVL, and 0.42 (95% CI 0.40, 0.44) for PPM.

There is high agreement between the ECL and clinical centers on continuous-wave Doppler-related measurements. In contrast, agreement is low for parameters that involve measurement of the LVOT diameter. These results provide important context for the interpretation of aortic valve performance in studies that lack central ECL evaluation.

ClinicalTrials.gov identifier: NCT02088554.