Background:  Left ventricular diastolic function is a complex assessment, as there is no single non-invasive parameter that provides a direct measurement of myocardial relaxation, myocardial compliance, or – as a surrogate - LV filling pressure. A combination of several parameters is therefore used to estimate the diastolic function.

Shear wave (SW) elastography is a novel method based on high frame rate echocardiography. SWs occur after mechanical excitation of the myocardium, e.g. after mitral valve closure (MVC), and their propagation velocity is directly related to myocardial stiffness (MS) that in turn is modulated by LV filling pressure.

Purpose: The aim of this study was to investigate whether SW speed is a surrogate marker for LV filling pressure and, thus, could be used to estimate left ventricular end-diastolic pressures (LVEDP) as marker of diastolic function.

Methods: We have prospectively enrolled 79 patients with a wide range of diastolic function, scheduled for heart catheterization so that LV filling pressures could be invasively measured. Patients with dysfunction in the anteroseptal wall , severe aortic stenosis, and a more than moderate mitral regurgitation or regional myocardial abnormalities were excluded.

Echocardiography was performed immediately after catheterization. SW elastography in parasternal long axis views of the left ventricle (LV) was performed using an experimental scanner (HD-PULSE) at 1050±220 frames per second. Tissue acceleration maps were extracted from an anatomical M-mode line along the midline of the LV septum. The SW propagation velocity at MVC was measured as the slope on the M-mode acceleration map (Figure A). Standard echocardiographic parameters of diastolic function were obtained with a high end ultrasound machine and analyzed as described in the guidelines.

Results: SW velocities at ED correlated well with the invasively measured LVEDP (R²=0.56, Figure B). In comparison, classical echocardiographic parameters correlated weakly with LV filling pressures (E/E’: R²=0.27; E/A: R²=0.26, Figure C).

For the detection of an elevated LVEDP above 16 mmHg, a cut off value for the SW velocity at MVC of  5.27 m/s (Figure A, B) was associated with a sensitivity of 92 %, a specificity of 88,6 % and an AUC of 94 % (Figure D).

Conclusions: End-diastolic shear wave velocities showed a significant correlation with the end-diastolic filling pressure and allowed to differentiate normal from elevated filling pressure which indicates a potential clinical value of the new method. And thus, the shear wave velocity could contribute to the non-invasive assessment of diastolic function.