Consolidated normal reference limits for right ventricular quantification by 3-dimensional echocardiography using a novel meta-analytic approach

Abstract

Purpose: Three-dimensional echocardiography (3DE) has superior accuracy and reproducibility for quantification of right ventricular (RV) size and function. However, the lack of consolidated normative data has been a factor in limiting its widespread clinical use. Methods: We performed a comprehensive review of the literature to identify all published studies that measured RV parameters by 3DE in healthy control groups. The parameters of interest were ejection fraction (RVEF), end-diastolic volume (RVEDV), end-systolic volume (RVESV); both non-indexed and indexed to body surface area. Age- and sex-specific normative data were extracted when available. Using a novel statistical approach, we performed a random-effects meta-analysis of these normative data to generate pooled mean values, upper reference values (mean + 2SD), lower reference values (mean – 2D), and 95% confidence intervals. Results: We identified 29 studies encompassing a total of 1610 healthy individuals. Semi-automated border detection algorithms were used in most studies. The results of the normative data meta-analysis are shown in the table. Using these results, the following 3DE cutoffs are recommended to define abnormality: RVEF 124.0 mL, RVEDVi >84.3 mL/m2, RVESV >61.0 mL, and RVESVi >38.5 mL/m2. Few studies reported age-specific (N=2) and sex-specific (N=4) data. Each decade of advancing age was associated with a gradual mild decline in volumes and preserved RVEF. Female sex was associated with mildly higher RVEF and moderately lower indexed and non-indexed volumes compared to males. View this table: Meta-analysis of normal reference values Conclusions: The proposed reference limits consolidate the body of normative data for RV quantification using 3DE, and thus should facilitate the clinical adoption of this technique. Further data are needed to evaluate age- and sex-specific differences.