Differentiation of hypertensive heart disease and hypertrophic cardiomyopathy with myocardial stiffness measurements: a shear wave imaging study using ultra-high frame rate echocardiography

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
M Cvijic ◽  
S Bezy ◽  
A Petrescu ◽  
P Santos ◽  
M Orlowska ◽  
...  
Keyword(s):  
Hypertrophic Cardiomyopathy ◽  
Shear Wave ◽  
Interventricular Septum ◽  
Hypertensive Heart Disease ◽  
Wall Stress ◽  
Left Ventricular ◽  
Frame Rate ◽  
Invasive Technique ◽  
Myocardial Stiffness ◽  
High Frame Rate

Abstract Background Recently, cardiac shear wave (SW) elastography, based on high frame rate (HFR) echocardiography, has been proposed as new non-invasive technique for assessing myocardial stiffness. As myocardial stiffness increases with increasing wall stress, differences in measured operating myocardial stiffness do not necessarily reflect differences in intrinsic myocardial properties, but can also be caused by mere changes in loading or chamber geometry. This complicates myocardial stiffness interpretation for different types of pathologic hypertrophy. Purpose To explore the relationship between myocardial stiffness and underlying pathological substrates for cardiac hypertrophy. Methods We included 20 patients with hypertension (HT) and myocardial remodelling (59±14 years, 75% male), 20 patients with hypertrophic cardiomyopathy (HCM) (59±16 years, 60% male) and 20 healthy controls (56±14 years, 75% male). Left ventricular (LV) parasternal long axis views were acquired with an experimental HFR scanner at 1293±362 frames per seconds. Propagation velocity of SW occurring after mitral valve closure in the interventricular septum (IVS) served as measure of operating myocardial stiffness (Figure A). To compare myocardial stiffness among hearts with differing loading conditions and chamber geometry, SW velocities were normalized to end-diastolic wall stress, estimated at IVS from regional wall thickness, longitudinal and circumferential regional radii of curvature, and non-invasively estimated LV end-diastolic pressure (EDP). Results SW velocities differed significantly between groups (p<0.001). The controls had the lowest SW velocities (4.02±0.97 m/s), whereas values between HT and HCM group were comparable (6.46±0.99 m/s vs. 7.00±2.10 m/s; p=0.738). Considering end-diastolic wall stress, HCM patients had the same SW velocity at lower wall stress compared to HT (Figure B), indicating higher myocardial stiffness in the HCM group. SW velocities normalized for wall stress indicated significantly different myocardial stiffness among all groups (p<0.001) (Figure C). In a multiple linear regression model, the underlying pathological substrate independently influenced SW velocity (beta 1.37, 95% CI (0.78–1.96); p<0.001), while wall stress did not significantly affect its value (p=0.479). Conclusions Our study demonstrated that SW elastography can detect differences in myocardial stiffness in hypertensive heart and hypertrophic cardiomyopathy. Additionally, our results suggest that SW velocity is dominated by underlying myocardial tissue properties. We hypothesize that differential changes in cardiomyocytes and/or the extracellular matrix contribute to the differential myocardial stiffening in different pathologic entities of LV hypertrophy. Thus, SW elastography could provide useful novel diagnostic information in the evaluation of LV hypertrophy. Figure A, B, C Funding Acknowledgement Type of funding source: None

scholarly journals 417 Can myocardial stiffness measurements distinguish the underlying pathology in hearts with thick walls? A shear wave imaging study using ultra-high frame rate echocardiography

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
M Cvijic ◽  
S Bezy ◽  
A Petrescu ◽  
P Santos ◽  
M Orlowska ◽  
...  
Keyword(s):  
Shear Wave ◽  
Diastolic Pressure ◽  
Interventricular Septum ◽  
Imaging Study ◽  
Wall Stress ◽  
Left Ventricular ◽  
Frame Rate ◽  
Invasive Technique ◽  
Radius Of Curvature ◽  
Myocardial Stiffness

Abstract Background Different pathophysiologic pathways in the development of left ventricular (LV) hypertrophy may alter passive myocardial stiffness differently. Recently, cardiac shear wave (SW) elastography has been proposed as new non-invasive technique for assessing myocardial stiffness. Purpose To explore the relationship between myocardial stiffness and the underlying pathological substrates for cardiac hypertrophy. Methods We included 17 patients with cardiac amyloidosis (AML) (69 ± 10 years, 41% male), 17 patients with hypertrophic cardiomyopathy (HCM) (59 ± 16 years, 65% male) matched for interventricular septum (IVS) thickness and 17 hypertensive patients (HT) with prominent myocardial remodelling (56 ± 15 years, 71% male). LV parasternal long axis views were acquired with an experimental ultrasound scanner at 1255 ± 354 frames per seconds. Myocardial acceleration maps were created from the HFR-datasets and an anatomical M-mode line was drawn along the midline of the IVS (Figure A). The propagation velocity of natural SWs occurring at mitral valve closure (MVC) was measured on these M-modes in order to assess operating myocardial stiffness. To compare myocardial stiffness among hearts with differing loading conditions and chamber geometry, SW velocities were normalized to operating end-diastolic wall stress. The end-diastolic wall stress was estimated at the IVS from regional wall thickness, longitudinal and circumferential regional radii of curvature, and noninvasively estimated left ventricular end-diastolic pressure (EDP). Results IVS thickness was significant different among groups (AML: 1.63 ± 0.33 cm, HCM: 1.69 ± 0.21 cm, HT: 1.48 ± 0.14 cm; p = 0.037). HT patients had significant higher septal radius of curvature compared to other two groups (p < 0.05), while the AML patients had the highest estimated EDP (p < 0.05). All groups had comparable, elevated SW velocities at MVC (AML: 6.49 ± 1.00 m/s, HCM: 6.46 ± 1.45 m/s, HT: 6.22 ± 0.96 m/s; p = 0.752). Considering end-diastolic wall stress, HT patients had the same SW velocity at higher wall stress compared to AML and HCM (Figure B), indicating lower myocardial stiffness in the HT group. SW velocities normalized for wall stress indicated significantly different myocardial stiffness among groups (p = 0.003) (Figure C). The HT group had the lowest normalized myocardial stiffness, whereas values of the AML group overlapped with the HCM group (p = 1.00). Conclusions Our study demonstrated that shear wave elastography can detect differences in myocardial stiffness in hearts with thick walls. Considering the effect of wall stress, our results suggest that factors other than chamber geometry and loading condition mediate myocardial stiffness in hearts with thick walls. We hypothesize that differential changes in cardiomyocytes and/or the extracellular matrix contribute to the differential myocardial stiffening in different pathologic entities of LV hypertrophy. Abstract 417 Figure.

P1501Can we measure the stiffening of hypertensive hearts non-invasively? A shear wave imaging study using ultra-high frame rate echocardiography

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M Cvijic ◽  
P Santos ◽  
A M Petrescu ◽  
S Bezy ◽  
M Orlowska ◽  
...  
Keyword(s):  
Left Atrium ◽  
Shear Wave ◽  
Interventricular Septum ◽  
Left Ventricular ◽  
Frame Rate ◽  
Volume Index ◽  
Healthy Controls ◽  
Myocardial Stiffness ◽  
High Frame Rate ◽  
Concentric Hypertrophy

Abstract Background Cardiac shear wave (SW) elastography is a novel technique based on high-frame-rate (HFR) echocardiography which has been shown to be related to myocardial stiffness. In this study we explore the relation between myocardial SW velocity and myocardial remodelling in remodelled hearts of patients with arterial hypertension (AH). Methods We prospectively included 33 treated AH patients with hypertrophic left ventricular (LV) remodelling (59±14 years, 55% male) and 26 aged matched healthy controls (55±15 years, 77% male). AH patients were further divided according to their LV geometric pattern into a concentric remodelling (CR) group (13 patients) and a concentric hypertrophy (CH) group (20 patients). LV parasternal long axis views were acquired with an experimental HFR ultrasound scanner (HD-PULSE) at 1266±317 frames per seconds. Myocardial acceleration maps were created from the HFR-datasets and an anatomical M-mode line was drawn along the midline of the interventricular septum (IVS). The propagation velocity of natural SWs occurring at mitral valve closure (MVC) was measured on these M-modes (Figure A) in order to assess passive myocardial stiffness. Standard echocardiography using a commercial scanner was performed to evaluate LV remodelling. Results SW velocities at MVC differed significantly between AH patients and controls (5.83±1.20 m/s vs. 4.04±0.96 m/s; p<0.001). Within the patient group, patients with CH had highest SW velocities at MVC (p<0.001), whereas values between controls and patients with CR were comparable (p=0.075) (Figure B). In AH patients, significant positive correlations were found between SW velocity at MVC and parameters of LV remodelling (IVS thickness: r=0.728, p<0.001; LV mass index: r=0.780, p<0.001, LV end-diastolic volume: r=0.604, p=0.008) (Figure C) and also parameters of diastolic function (E/e': r=0.495, p=0.005, left atrium diameter: r=0.866, p<0.001, left atrium volume index: r=0.661, p<0.001). Figure A, B, C Conclusions SW velocity – and therefore myocardial stiffness – is higher in AH patients compared to healthy controls and increases with increasing severity of hypertensive heart disease. Patients with concentric remodelling have still close-to-normal passive myocardial properties while patients with concentric hypertrophy show significant stiffening. Echocardiographic shear wave elastography is a promising new technique for the non-invasive assessment of myocardial stiffness and might provide valuable new insights into myocardial function and the pathophysiology of myocardial disease.

scholarly journals Interplay of cardiac remodelling and myocardial stiffness in hypertensive heart disease: a shear wave imaging study using high-frame rate echocardiography

2019 ◽  
Vol 21 (6) ◽  
pp. 664-672 ◽  
Author(s):  
Marta Cvijic ◽  
Stéphanie Bézy ◽  
Aniela Petrescu ◽  
Pedro Santos ◽  
Marta Orlowska ◽  
...  
Keyword(s):  
Heart Disease ◽  
Interventricular Septum ◽  
Hypertensive Heart Disease ◽  
Imaging Study ◽  
Wall Stress ◽  
Left Ventricular ◽  
Frame Rate ◽  
Healthy Controls ◽  
Myocardial Stiffness ◽  
Concentric Hypertrophy

Abstract Aims To determine myocardial stiffness by means of measuring the velocity of naturally occurring myocardial shear waves (SWs) at mitral valve closure (MVC) and investigate their changes with myocardial remodelling in patients with hypertensive heart disease. Methods and results Thirty-three treated arterial hypertension (HT) patients with hypertrophic left ventricular (LV) remodelling (59 ± 14 years, 55% male) and 26 aged matched healthy controls (55±15 years, 77% male) were included. HT patients were further divided into a concentric remodelling (HT1) group (13 patients) and a concentric hypertrophy (HT2) group (20 patients). LV parasternal long-axis views were acquired with an experimental ultrasound scanner at 1266 ± 317 frames per seconds. The SW velocity induced by MVC was measured from myocardial acceleration maps. SW velocities differed significantly between HT patients and controls (5.83 ± 1.20 m/s vs. 4.04 ± 0.96 m/s; P &lt; 0.001). In addition, the HT2 group had the highest SW velocities (P &lt; 0.001), whereas values between controls and the HT1 group were comparable (P = 0.075). Significant positive correlations were found between SW velocity and LV remodelling (interventricular septum thickness: r = 0.786, P &lt; 0.001; LV mass index: r = 0.761, P &lt; 0.001). SW velocity normalized for wall stress indicated that myocardial stiffness in the HT2 group was twice as high as in controls (P &lt; 0.001), whereas values of the HT1 group overlapped with the controls (P = 1.00). Conclusions SW velocity as measure of myocardial stiffness is higher in HT patients compared with healthy controls, particularly in advanced hypertensive heart disease. Patients with concentric remodelling have still normal myocardial properties whereas patients with concentric hypertrophy show significant stiffening.

scholarly journals Relationship between myocardial properties and myocardial stiffness in hearts with thick walls: a shear wave imaging study using ultra-high frame rate echocardiography

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
M Cvijic ◽  
A Petrescu ◽  
S Bezy ◽  
P Santos ◽  
M Orlowska ◽  
...  
Keyword(s):  
Shear Wave ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Frame Rate ◽  
Local Geometry ◽  
Cavity Pressure ◽  
Invasive Approach ◽  
Tissue Properties ◽  
Myocardial Stiffness ◽  
High Frame Rate

Abstract Funding Acknowledgements Type of funding sources: None. Background Shear wave (SW) imaging, based on high frame rate (HFR) echocardiography, is a new non-invasive approach for assessing myocardial stiffness. Operating myocardial stiffness increases with increasing wall stress, therefore measured myocardial stiffness does not necessarily reflect intrinsic myocardial properties only, but can be influenced by cavity pressure and chamber geometry. Purpose  To explore the relationship between local myocardial geometry, cavity pressure and pathological substrate with SW velocity and to determine to which extent the above mentioned factors influence SW velocity. Methods We included 26 healthy controls (55 ± 14 years, 77 % male) and 61 patients with thick heart (24 patients with cardiac amyloidosis (AML) [70 ± 9 years, 52 % male], 37 patients with hypertrophic cardiomyopathy (HCM) [54 ± 14 years, 78 % male]). Left ventricular (LV) parasternal long axis views were acquired with an experimental HFR scanner at 1142 ± 282 frames per seconds. Propagation velocity of the SW occurring after mitral valve closure in the interventricular septum (IVS) served as measure of myocardial stiffness (Figure A). While conventional echocardiographic measurements were used to evaluate local myocardial geometry (LV end-diastolic diameter [EDD], IVS thickness) and LV cavity pressure (LV diastolic pressure-estimated by E/e` and LV systolic pressure-estimated by systolic blood pressure and potential LV outflow gradient in HCM). Results  LV cavity pressure and local geometry differed significantly between controls and patients (p &lt; 0.05, for all, Figure B). SW velocity correlated with cavity pressure (E/e`: r = 0.375, p &lt; 0.001, LV systolic pressure: r = 0.264, p = 0.020) and local geometry (IVS thickness: r = 0.700, p &lt; 0.001; EDD: r=-0.307, p = 0.007) and differed significantly among groups (Figure C). Multivariate analysis revealed that SW velocity was independently related only with the pathological substrate and IVS thickness (p = 0.006 and p &lt; 0.001, respectively). In a regression model, the pathological substrate, cavity pressure and local geometry accounted for 56% of variation in SW velocity (p &lt; 0.001), while the pathological substrate alone accounted for nearly half of the variance (R2 = 0.44, p &lt; 0.001) (Figure D). Conclusions  Our study demonstrated that SW velocity is related to both pathological substrate and local geometry and LV pressures. Additionally, our results suggest that variations in myocardial tissue properties had the most influence on SW velocity, while LV pressure and local geometry played a minor role. Therefore, the changes in SW velocity reflect predominantly tissue properties that are altered by underlining disease rather than cavity pressure and morphological abnormalities. Thus, SW elastography could provide useful novel diagnostic information in the evaluation of cardiomyopathies. Abstract Figure A, B, C, D

scholarly journals Shear wave elastography by high frame rate echocardiography can detect diffuse myocardial fibrosis after heart transplantation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Petrescu ◽  
S Bezy ◽  
M Cvijic ◽  
P Santos ◽  
J Duchenne ◽  
...  
Keyword(s):  
Shear Wave ◽  
Myocardial Fibrosis ◽  
Myocardial Injury ◽  
Shear Wave Elastography ◽  
Diffuse Myocardial Fibrosis ◽  
Frame Rate ◽  
Myocardial Stiffness ◽  
High Frame Rate ◽  
Native T1 ◽  
Propagation Velocities

Abstract Background Myocardial fibrosis is fundamental in the development of cardiac failure, regardless of ethiology. In both animal models and humans it has been shown that diffuse myocardial fibrosis (DMF) contributes to functional impairment, especially to increased passive myocardial stiffness, which is an important pathophysiological determinant of left ventricular diastolic dysfunction. Histological examination is the gold standard for myocardial fibrosis quantification, however, it requires endomyocardial biopsies which are invasive and not without risk. Echocardiographic shear wave (SW) elastography, based on high frame rate imaging, is an emerging approach for measuring myocardial stiffness in vivo. Natural 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, thus providing an opportunity to assess myocardial stiffness at end-diastole. Purpose The aim was to investigate if propagation velocities of natural SWs can be used to detect diffuse myocardial fibrosis in a cohort of heart transplant recipients. Methods We prospectively enrolled 22 patients (10.3±6.3 years after HTx) that underwent CMR during their annual check-up. We performed SW elastography in parasternal long axis views of the left ventricle using a fully programmable experimental scanner (HD-PULSE) equipped with a clinical phased array transducer (Samsung Medison P2–5AC) at 1100±250 frames per second. The SW propagation velocities at MVC were measured in the basal LV septum. Native T1 and extracellular volume (ECV) were measured at the same segment to evaluate DMF. A cut-off value for native T1 of 1040 ms and for ECV of 29% was used to define DMF in our cohort. Results We found good correlations between SW velocities and both myocardial T1 (r=0.80, p&lt;0.0001, Figure A) and ECV (r=0.64, p=0.003, Figure B) measured with CMR. Further, we derived reference thresholds of natural SW velocities to identify DMF in HTx patients. The optimal cut-off value of SW velocity to identify patients with nativT1&gt;1040 ms was 4.84 m/s (AUC 0.81, sensitivity 82%, specificity 82%, Figure C). To identify patients with ECV&gt;0.29 the cut-off value of SW velocity was 4.74 m/s (AUC 0.74, sensitivity 73%, specificity 78%, Figure D). Conclusions End-diastolic shear wave propagation velocities, as measure of myocardial stiffness, showed a good correlation with CMR defined diffuse myocardial injury. Values higher than 4.74 m/s could identify diffuse myocardial injury in HTX patients with a good sensitivity and good specificity. These findings thus suggest that shear wave elastography has the potential to become a valuable non-invasive method for the detection of diffuse myocardial fibrosis. Funding Acknowledgement Type of funding source: None

Shear wave elastography: can we estimate filing pressures?

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A.E Werner ◽  
S Bezy ◽  
M Orlowska ◽  
G Kubiak ◽  
W Desmet ◽  
...  
Keyword(s):  
Diastolic Function ◽  
Shear Wave ◽  
Propagation Velocity ◽  
Shear Wave Elastography ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Frame Rate ◽  
Funding Source ◽  
High Frame Rate ◽  
Non Invasive

Abstract Background The assessment of the left ventricular diastolic function is complex, 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. Estimation of diastolic function is therefore based on the combination of many parameters. Shear wave (SW) elastography (SWE) 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). Purpose The aim of this study was to investigate if velocities of natural shear waves are related to MS at end diastole (ED) and, thus, could be used to estimate left ventricular end-diastolic pressures (LVEDP) as marker of diastolic function. Methods So far, we have prospectively enrolled 30 patients with a wide range of diastolic function, scheduled for heart catheterization so that LV filling pressures could be invasively measured. Patients with severe aortic stenosis, mitral stenosis of any degree and a more than moderate mitral regurgitation, as well as regional myocardial abnormalities or dysfunction in the anteroseptal wall 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 1100±250 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). Results SW velocities at ED correlated very well with the invasively measured LVEDP (r=0.815, p&lt;0.001, Figure B). In comparison, classical echocardiographic parameters correlated only weakly or not with LVEDP (E/A: r=0.528, p=0.036, Figure C; E/e': r=−0.169, p=0,531, Figure D) with LVEDP. For the detection of an elevated LVEDP above 15 mmHg, a cut off value for the SW velocity at MVC of 3.75 m/s was associated with a Sensitivity of 92.9% and a Specificity of 83.3%. Conclusions End-diastolic shear wave velocities, measured by high frame rate shear wave elastography, showed a significant correlation with the end-diastolic filling pressure of the LV indicating a potential clinical value of the new method for a non-invasive and direct assessment of LV diastolic function. More patients will be included to confirm these findings. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fonds Wetenschappelijk Onderzoek Flanderen (Research Foundation Flanders)

scholarly journals The influence of hemodialysis-induced preload changes on the propagation speed of natural shear waves

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
S Bezy ◽  
M Orlowska ◽  
A Van Craenenbroeck ◽  
M Cvijic ◽  
J Duchenne ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Shear Wave ◽  
Wave Speed ◽  
Shear Waves ◽  
Propagation Speed ◽  
Left Ventricular ◽  
Frame Rate ◽  
High Frame Rate ◽  
Shear Wave Speed ◽  
Wave Propagation Speed

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation - Flanders (FWO) Background Shear wave elastography (SWE) is a novel ultrasound technique based on the detection of transverse waves travelling through the myocardium using high frame rate echocardiography. The propagation speed of these shear waves is dependent on the stiffness of the myocardium. Previous studies have shown the potential of SWE for the non-invasive assessment of myocardial stiffness. It is unclear, however, if preload changes lead to measurable changes in the shear wave propagation speed in the left ventricle. In patients undergoing hemodialysis, the volume status is acutely changed. In this way, the effect of preload changes on shear wave speed can be assessed. Purpose The aim of this study was to explore the influence of preload changes on end-diastolic shear wave propagation speed. Methods Until now, 6 patients (age: 80[53-85] years; female: n = 2) receiving hemodialysis treatment were included. Echocardiographic images were taken before and every hour during a 4 hour hemodialysis session. Left ventricular parasternal long-axis views were acquired with an experimental high frame rate ultrasound scanner (average frame rate: 1016[941-1310] Hz). Standard echocardiography was performed with a conventional ultrasound machine. Shear waves were visualized on tissue acceleration maps by drawing an M-mode line along the interventricular septum. Shear wave propagation speed after mitral valve closure (MVC) was calculated by measuring the slope of the wave pattern on the acceleration maps (Figure A). Results Over the course of hemodialysis, the systolic (141[135-156] mmHg vs. 165[105-176] mmHg; p = 0.35 among groups) and diastolic blood pressure (70[66-75] mmHg vs. 82[63-84] mmHg; p = 0.21 among groups), heart rate (56[54-73] bmp vs. 57[50-67] bpm; p = 0.76 among groups), E/A ratio (1.6[0.7-1.8] vs. 1.2[0.6-1.4]; p = 0.43 among groups) and E/e’ (14[9-15] vs. 9[8-13]; p = 0.24 among groups ) remained the same. The ultra-filtrated volumes are shown in Figure B. The shear wave propagation speed after MVC gradually decreased during hemodialysis (6.7[5.4-9.7] m/s vs. 4.4[3.6-9.0] m/s; p = 0.04 among groups) (Figure C). There was a moderate negative correlation between shear wave speed and the ultra-filtrated volume (r=-0.63; p &lt; 0.01) (Figure D). Conclusion The shear wave propagation speed at MVC significantly decreased over the course of hemodialysis and correlated to the ultra-filtrated volume. These results indicate that alterations in left ventricular preload affect the speed of shear waves at end-diastole. End-diastolic shear wave speed might therefore be a potential novel parameter for the evaluation of the left ventricular filling state. More patients will be included in the future to further explore these findings. Abstract Figure.

scholarly journals Myocardial stiffness assessed by natural shear wave elastography is related to pressure-volume loop derived parameters

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
S Bezy ◽  
A Caenen ◽  
J Duchenne ◽  
M Orlowska ◽  
M Amoni ◽  
...  
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Propagation Speed ◽  
Shear Wave Elastography ◽  
Frame Rate ◽  
Myocardial Stiffness ◽  
High Frame Rate ◽  
Shear Wave Speed ◽  
Non Invasive ◽  
Operating Chamber

Abstract Background Several cardiovascular disorders are accompanied by a stiffening of the myocardium and may result in diastolic heart failure. The non-invasive assessment of myocardial stiffness could therefore improve the understanding of the pathophysiology and guide treatment. Shear wave elastography (SWE) is a recent technique with tremendous potential for evaluating myocardial stiffness in a non-invasive way. Using high frame rate echocardiography, the propagation speed of shear waves is evaluated, which is directly related to the stiffness of the myocardium. These waves are induced by for instance mitral valve closure (MVC) and propagate throughout the cardiac muscle. However, validation of SWE against an invasive gold standard method is lacking. Purpose The aim of this study was to compare echocardiographic shear wave elastography against invasive pressure-volume loops, a gold standard reference method for assessing chamber stiffness. Methods In 15 pigs (31.2±4.1 kg) stiffness of the myocardium was acutely changed by inducing ischemia/reperfusion (I/R) injury. For this, the proximal LAD was balloon occluded for 90 minutes with subsequent reperfusion for 40 minutes. Conventional and high frame rate echocardiographic images were acquired simultaneously with pressure-volume loops during baseline conditions and after the induction of the I/R injury. Preload was reduced in order to acquire a set of pressure-volume loops to derive the end-diastolic pressure volume relation (EDPVR). From the EDPVR, the stiffness coefficient β and the operating chamber stiffness dP/dV were obtained. High frame rate echocardiographic datasets of the parasternal long axis view were acquired with an experimental ultrasound scanner (HD-PULSE) at an average frame rate of 1304±115 Hz. Tissue acceleration maps were obtained by drawing an M-mode line along the interventricular septum in order to visualize shear waves after MVC (at end-diastole). The propagation speed was assessed by semi-automatically measuring the slope (Figure A). Results I/R injury led to an elevated chamber stiffness constant β (0.09±0.03 1/ml vs. 0.05±0.01 1/ml; p&lt;0.001) and operating chamber stiffness dP/dV (1.09±0.38 mmHg/ml vs. 0.50±0.18 mmHg/ml; p&lt;0.01). Likewise, shear wave speed after MVC increased after the induction of the I/R injury in comparison to baseline (6.1±1.2 m/s vs. 3.2±0.8 m/s; p&lt;0.001). Shear wave speed had a moderate positive correlation with β (r=0.63; p&lt;0.001) (Figure B) and a strong positive correlation with dP/dV (r=0.81; p&lt;0.001) (Figure C). Conclusion End-diastolic shear wave speed is strongly related to chamber stiffness, assessed invasively by pressure-volume loops. These results indicate that shear wave propagation speed could be used as a novel non-invasive measurement of the mechanical properties of the ventricle. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): FWO - Research Foundation Flanders

scholarly journals Shear wave elastography: can we discover elevated diastolic filling pressures?

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
AE Werner ◽  
S Bezy ◽  
M Orlowska ◽  
G Kubiak ◽  
J Duchenne ◽  
...  
Keyword(s):  
Diastolic Function ◽  
Shear Wave ◽  
Propagation Velocity ◽  
Shear Wave Elastography ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Frame Rate ◽  
Diastolic Filling ◽  
High Frame Rate ◽  
Echocardiographic Parameters

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): University Hospitals (Uz) Leuven Background  The assessment of the left ventricular diastolic function is complex, as there is no single invasive parameter that provides a direct measurement of myocardial relaxation, myocardial compliance, or – as a surrogate - LV filling pressure. Estimation of diastolic function is therefore based on the combination of several parameters. 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). Purpose The aim of this study was to investigate if velocities of natural shear waves are related to MS at end-diastole (ED) and, thus, could be used to estimate left ventricular end-diastolic pressures (LVEDP) as marker of diastolic function. Methods So far, we have prospectively enrolled 42 patients with a wide range of diastolic function, scheduled for heart catheterization so that LV filling pressures could be invasively measured. Patients with severe aortic stenosis, mitral stenosis of any degree and a more than moderate mitral regurgitation, as well as regional myocardial abnormalities or dysfunction in the anteroseptal wall 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 1100 ± 250 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. Results SW velocities at ED correlated well with the invasively measured LVEDP (r = 0.74, p &lt; 0.001, Figure B). In comparison, classical echocardiographic parameters correlated only weakly with LVEDP (E/A: r = 0.398, p = 0.02, Figure C; E/E’: r = 0.204, p = 0.247, Figure D). For the detection of an elevated LVEDP above 15 mmHg, a cut off value for the SW velocity at MVC of 4.395 m/s (Figure A) was associated with a sensitivity of 91.3% and a specificity of 90.9%. Conclusions End-diastolic shear wave velocities, measured by high frame rate shear wave elastography, showed a significant correlation with the end-diastolic filling pressure of the LV and allowed to differentiate normal from elevated filling pressure which indicates a potential clinical value of the new method for a non-invasive and direct assessment of LV diastolic function. More patients will be included to confirm these findings. Abstract Figure.

scholarly journals Local myocardial stiffness variations identified by high frame rate shear wave echocardiography

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Mihai Strachinaru ◽  
Johan G. Bosch ◽  
Arend F. L. Schinkel ◽  
Michelle Michels ◽  
Lida Feyz ◽  
...  
Keyword(s):  
Shear Wave ◽  
Therapy Group ◽  
Shear Waves ◽  
Interventricular Septum ◽  
Intervention Group ◽  
Muscle Stiffness ◽  
Frame Rate ◽  
Velocity Variation ◽  
High Frame Rate ◽  
Group 3

Abstract Background Shear waves are generated by the closure of the heart valves. Significant differences in shear wave velocity have been found recently between normal myocardium and disease models of diffusely increased muscle stiffness. In this study we correlate in vivo myocardial shear wave imaging (SWI) with presence of scarred tissue, as model for local increase of stiffness. Stiffness variation is hypothesized to appear as velocity variation. Methods Ten healthy volunteers (group 1), 10 hypertrophic cardiomyopathy (HCM) patients without any cardiac intervention (group 2), and 10 HCM patients with prior septal reduction therapy (group 3) underwent high frame rate tissue Doppler echocardiography. The SW in the interventricular septum after aortic valve closure was mapped along two M-mode lines, in the inner and outer layer. Results We compared SWI to 3D echocardiography and strain imaging. In groups 1 and 2, no change in velocity was detected. In group 3, 8/10 patients showed a variation in SW velocity. All three patients having transmural scar showed a simultaneous velocity variation in both layers. Out of six patients with endocardial scar, five showed variations in the inner layer. Conclusion Local variations in stiffness, with myocardial remodeling post septal reduction therapy as model, can be detected by a local variation in the propagation velocity of naturally occurring shear waves.

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