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<0.0001 for all pre- vs. post-standardization comparisons) (Figure). CVs of post-standardization (Q9 and Q10) GLS were similar to those of LVEF. The concordance for contemporary strain software (E12 vs Q9) was similar to that of an independent group of 31 patients (0.06±0.05 vs. 0.07±0.05, p=0.11).
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.
Author Disclosures: H. Yang: Research Grant; Modest; HY is supported by a Health Professional Scholarship from the National Heart Foundation of Australia (100307). N. Fukuda: None. S. Wahi: None. H. Oe: None. M. Saito: None. J.D. Thomas: None. T. Marwick: None. K. Negishi: None.
- © 2014 by American Heart Association, Inc.