Determining the thresholds for abnormal left ventricular strains in healthy subjects by echocardiography: a meta-analysis

Abstract

Background: Left ventricular global longitudinal strain (LVGLS), circumferential strain (LVGCS) and radial strain (LVGRS) are echocardiographic parameters with wide clinical applicability. However, the thresholds for abnormal left ventricular (LV) strains, particularly the lower limits of normal (LLN), are not well established. This meta-analysis determined the mean and LLN of two-(2D) and three-dimensional (3D)LV strain in healthy subjects and factors that influence strain measurements.Methods: We searched PubMed, Embase and Cochrane databases until 31 December 2019 for studies reporting left ventricular (LV) global strain in at least 50 healthy subjects. We pooled means and LLNs of 2D and 3D LV strain using random-effects models, and performed subgroup and meta-regression analysis for LVGLS. Results: Forty-four studies were eligible totaling 8,910 subjects. The pooled means and LLNs (95% confidence intervals) were −20.1% (−20.7%, −19.6%) and −15.4% (−16.0%, −14.7%) respectively for 2D-LVGLS; −21.9% (−23.4%, −20.3%) and −15.3% (−16.9%, −13.8%) respectively for 2D-LVGCS; and 48.4% (43.8%, 53.0%) and 25.5% (17.8%, 33.1%) respectively for 2D-LVGRS. All pooled analyses demonstrated significant heterogeneity, and means and LLNs of and 3D-LV strains differed marginally from 2D. Only vendor software was associated with differences in pooled means and LLN of 2D-LVGLS.Conclusions: In conclusion, pooled means and LLNs of 2D-and 3D-LV global strain parameters in healthy subjects were reported. Based on the pooled LLNs, thresholds for abnormal, borderline and normal strains can be defined, such as less negative than −14.7%, between −14.7% and −16.0% and more negative than −16.0% respectively for 2D-LVGLS, and 2D-LVGLS values are only affected by vendor software.

Defining the reference range for right ventricular systolic strain by echocardiography in healthy subjects: A meta-analysis

“…Based on the mean and LLN with their SD or SE, meta-analysis was performed using the DerSimonian-Laird method random effects models to estimate pooled RV strain parameter means and LLNs with 95%CIs, and Forest Plots presented in all eligible studies reporting the RV strain parameters analyzed [9,10]. These analyses were also performed for purpose of sensitivity analysis performed for cohort studies of healthy subjects only and excluding case-controlled studies, and performed separately by strain vendor software if reported in at least 2 studies due to presumptive differences.…”

“…The pooled LLNs and their respective 95%CIs reported in this study, rather than the pooled means, are necessary to defining reference ranges [9,10]. The 95%CI of LLN reflects the range…”

“…the SE of the LLN using Bland's formula [9,10,12]. These estimates were then pooled using meta-analysis techniques to provide estimates of the LLN with 95%CI from multiple studies, with greater power and precision than which individual studies can provide.…”

“…Recently, we performed meta-analysis to not only provide the point estimate of average value, but also the reference ranges for normal values of left ventricle strain parameters obtained by 2-and 3-dimensional echocardiography along with magnetic resonance imaging for the first time [9,10]. This meta-analysis aims to pool the means and LLN of two-dimensional RVGLS and RVFWLS parameters measured by echocardiography in healthy subjects to determine reference ranges.…”

Nuances in Defining Normal Ranges for Chamber Quantification With Cardiovascular Magnetic Resonance

“…The implications are that biomarker values should not have a binary interpretation of normal or abnormal but should be categorized into 3 groups. 4 Measurements within the 95% CI of the LRV or URV are deemed borderline because it is uncertain whether the measurement is above or below the true LRV or URV. Measurements outside the 95% CI and closer to the mean are considered normal, and measurements outside the 95% CI and further from the mean are considered abnormal.…”