Noninvasive assessment of left ventricular performance using pressure-volume loops, blood propulsion and strain tensors: results from the World Alliance of Societies of Echocardiography study

Abstract

Aims: Left ventricular (LV) pressure-volume (PV) loops, LV strain tensors, and intraventricular pressure gradients (IVPG) provide physiological information on cardiovascular performance and the interaction between LV and arterial system. Given that acquisition of PV loops and IVPG require invasive measurements, there is interest in the development of new noninvasive tools. This work aims to (i) demonstrate the application of noninvasive methods based on three-dimensional echocardiography (3DE) for describing PV loops and haemodynamic performance in terms of IVPG, in conjunction to LV strain tensors and (ii) to determine sex-, age-, and race-related normative values.

Methods and results: This work is based on 3DE data from the World Alliance of Societies of Echocardiography study (1403 normal subjects). It applies physics-based techniques to construct noninvasive PV loops, assess blood propulsion using IVPG and 3D deformation using LV strain tensors. Sex- and age-related differences in strain and PV loop are limited to some parameters only, while haemodynamic performance in terms of IVPG does not vary with sex and is reduced with aging. Asian populations are characterized by smaller hearts, higher EF, strain, and PV loop scores than Whites, which in turn have similar LV size to Blacks and higher EF, strain, and PV loop scores, while IVPG was more similar across the populations.

Conclusion: This study analysed a large normal population with physics-based methods that allow a deep mechanical and haemodynamic analysis of 3DE with 70% feasibility and provided reference values for a series of advanced parameters and their dependency on sex, age, and race.

Keywords: cardiac blood flow; cardiac strain; intraventricular pressure gradient; left ventricular function; pressure-volume loop; three-dimensional echocardiography.