Abstract 17885: Inter-vendor Concordance of Strain is Analogous to Ejection Fraction After Strain Standardization Initiative

Background: Disagreement of strain measurements among different vendors has provided an obstacle to the clinical use of strain. A joint standardization task force between professional societies and industry was initiated to reduce inter-vendor variability of strain. Although feedback from this process has been used in software upgrades, little is known about the effects of efforts to improve conformity. We sought whether inter-vendor agreement for global longitudinal strain (GLS) has improved after standardization initiatives. Methods: 82 subjects (55% male) prospectively underwent two sequential examinations using two ultrasound systems (Vivid E9 vs. iE33). GLS was calculated using proprietary software EchoPAC BT12 (E12) and BT13 (E13) versus QLAB 8 (Q8), QLAB 9 (Q9) and QLAB 10 (Q10). Differences in GLS were evaluated with Bland-Altman plots. Coefficients of variation (CVs) were compared using Friedman test and compared with CVs of LV volumes and ejection fraction (EF). Results: The study population had wide ranges of age (18-95, mean 52±20.3 years) and body mass index (16-43, mean 25±6 kg/m2). Their LVEF was 58±12 % (14 -72%). Between-vendor differences in GLS showed larger CVs in the comparisons among pre-standardization software versions (Q8 vs E12 and E13) than those from post-standardization (Q9 and Q10 versus E12 and E13) (p Conclusion: Subsequent to the joint standardization task force, there has been improvement in between-vendor concordance in GLS, the variability of which is now analogous to that of LVEF. The removal of concerns about measurement variability should allow wider use of GLS.