Abstract Body (Do not enter title and authors here): Background: Current conventional echocardiographic assessment of diastolic function relies on predicting left ventricular (LV) filling pressure as a surrogate of diastolic function. High frame rate (HFR) Shear wave (SW) imaging is emerging as an innovative parameter for assessing myocardial stiffness, a key determinant of diastolic function. Natural SW are induced by valve closure (i.e. mitral valve closure (MVC)). Little is known so far, to which extent SWs could reflect changes in diastolic LV filling pressures.
Purpose: We aimed at investigating the relationship between natural SW after MVC and LV diastolic pressures in an attempt to set up a cut-off value beyond which, elevated LV pressure can be suspected indicating diastolic dysfunction.
Methods: Thirty patients (mean age 68.4±9.9 years) scheduled for clinically indicated left heart catheterization were prospectively recruited. Left ventricular end-diastolic pressure (LVEDP) was measured during the catheterization. Immediately afterwards, conventional as well as HFR (1167 ±86 Hz) echocardiography was performed. We drew an anatomical M-mode along the anteroseptal wall in the parasternal long axis view from base to apex and the display was colour coded for tissue acceleration. SWs appeared immediately after MVC as tilted green bands and their propagation velocity was measured semi-automatically (Figure 1).
Results: LVEDP in our cohort ranged from 7.5 to 29.5 mmHg. From conventional echocardiographic parameters, only mitral inflow to mitral relaxation velocity ratio (E/e’) correlated moderately with LVEDP (r=0.51, p=0.006). SW velocities after MVC showed strong positive correlation with LVEDP (r=0.78, p<0.001) (Figure 2). A cut-off value for SW velocity of 5.8 m/s showed an excellent ability to discriminate normal from elevated LVEDP (AUC: 0.98; Sensitivity: 90%, specificity: 100%, accuracy: 97%) (Figure 3).
Conclusions: Our data showed that SW velocities at end-diastole after MVC could predict elevated LV filling pressures accurately. Natural shear wave imaging appears as a promising innovative tool for assessment of diastolic function.