Right ventricular pressure-strain relationship-derived myocardial work reflects contractility: validation with invasive pressure-volume analysis

Abstract

Background Three-dimensional (3D) echocardiography-derived right ventricular (RV) ejection fraction (EF) and global longitudinal strain (GLS) are valuable RV functional markers; nevertheless, they are substantially load-dependent. Global myocardial work index (GMWI) adjusts myocardial deformation to instantaneous pressure; therefore, it may better reflect contractility. Accordingly, we aimed to calculate RV GMWI using 3D echocardiography and examine its relationship with RV contractility's gold standard invasive measurement. Methods Sixty patients (65±14 years, 65% female) with suspected or established pulmonary hypertension were enrolled. Detailed 3D echocardiography was performed to quantify RV EF and GLS using the ReVISION software. Patients underwent RV pressure-conductance catheterization to obtain the RV pressure curve and to assess contractility (end-systolic elastance - Ees) and ventriculo-arterial coupling (Ees/arterial elastance - Ees/Ea). RV GMWI was calculated using the RV GLS and the RV pressure trace curve. Results While neither RV EF (r=-0.143, p=0.275) nor GLS (r=-0.067, p=0.611) correlated with Ees, GMWI showed a strong correlation with it (r=0.669, p<0.001). In contrast, RV EF and GLS showed a relationship with Ees/Ea (RVEF: r=0.552; GLS: r=0.460, both p<0.001). By dividing the population based on the Reveal Lite 2 risk classification, EF and GLS showed a significant decrease only in the high-risk group (low vs. intermediate vs. high risk; EF: 48.8±6.6 vs. 44.0±9.4 vs. 35.0±7.8%, ANOVA p<0.001; GLS: 18.6±3.6 vs. 17.0±4.5 vs. 13.3±3.9%, ANOVA p<0.001), whereas GMWI already showed an increase in the intermediate group (550±267 vs. 831±361 vs. 797±265 mmHg%, ANOVA p<0.01). Conclusions RV EF and GLS reflect ventriculo-arterial coupling, while GMWI strongly correlates with contractility. RV GMWI may emerge as a useful clinical tool for risk stratification and follow-up in patients with pulmonary hypertension.