Tomoko Kamata

Characteristic myocardial strain identified in hypertrophic cardiomyopathy subjects with preserved left ventricular ejection fraction using a novel multi-layer transthoracic echocardiography technique

PURPOSE In order to evaluate compensatory mechanisms in hypertrophic-cardiomyopathy (HCM) subjects with preserved left-ventricular (LV) ejection-fraction (EF), we measured myocardial percentage endocardial strain dependency, as represented by 2D LV global longitudinal (GLS) and circumferential-strain (GCS), using a novel, multi-layer, speckle-tracking transthoracic-echocardiography (TTE) technique. METHODS A total of 60 subjects (40 HCM with preserved LV EF (30 male; 62 ± 15 years, all LV EF>50%)) and 20 controls (10 male; 59 ± 10 years) underwent TTE (Vivid-E9). Quantitative strain-measurements of: endocardial, all and epicardial layers were performed at each-site. We defined percentage endocardial strain dependency as the ratio of endocardial strain to epicardial strain. RESULTS Absolute GLS values at all views in all, endocardial and epicardial myocardial layers were significantly smaller in HCM subjects than in controls (all P<0.001). There were no significant differences between both-groups in absolute GCS values in the endocardial layers, at the mitral valve and papillary muscle levels. Percentage endocardial GCS dependency at all levels were greater in HCM subjects than in controls (all P<0.01). In HCM subjects, percentage endocardial GCS dependency at the mitral valve and papillary muscle levels revealed significant, moderate, negative correlations with LV end-diastolic and systolic dimensions (correlation coefficients -0.505, -0.451 (mitral valve level) and -0.533, -0.591 (papillary muscle level), respectively). CONCLUSIONS In HCM subjects with preserved LV EF, 2D LV GLS was lower than in controls, but endocardial GCS was maintained in compensation for reduction in endocardial GLS; thus percentage endocardial GCS dependency may increase, and the larger the LV size, the smaller this compensatory effect.

Resting multilayer 2D speckle-tracking transthoracic echocardiography for the detection of clinically stable myocardial ischemic segments confirmed by invasive fractional flow reserve. Part 1: Vessel-by-vessel analysis.

PURPOSE To detect stable ischemic left ventricular (LV)-segments confirmed via invasive fractional flow reserve (FFR) by quantitative longitudinal-strain (LS) determined using resting multilayer TTE. METHODS A retrospective analysis of 39 stable patients (32 males; 65.8±11.9years) with 46 coronary arteries with ≥50% stenosis confirmed by invasive coronary angiography who underwent invasive FFR measurement and TTE (Vivid E9, GE). On TTE, regional LS (absolute values) were calculated in whole, endocardial, and epicardial layers perfused by stenotic coronary arteries. RESULTS Of the 46 vessels, FFR values of <0.75, ≥0.75, ≤0.80 and >0.80 were observed in 17, 29, 27 and 19 vessels, respectively. In a vessel-by-vessel analysis, the whole-layer and endocardial LS were significantly smaller in LV-segments perfused by vessels with an FFR<0.75 than in those with an FFR≥0.75, but epicardial LS was not. In ROC curves, the best cutoff values of whole-layer, endocardial and epicardial LS were, respectively, 14.0% (sensitivity, 94%; specificity 38%; area under the curve, 0.685), 10.0% (47%; 86%; 0.664) and 14.0% (100%; 24%; 0.640) to detect LV-segments with an FFR<0.75; and 14.0% (82%; 37%; 0.561), 10.0% (33%; 84%; 0.573), and 14.0% (89%; 21%; 0.538) to detect LV-segments with an FFR≤0.80. CONCLUSION For stable subjects with coronary arteries with ≥50% stenosis, the regional whole-layer and endocardial LS were significantly smaller in LV-segments perfused by vessels with an FFR<0.75 than in those with an FFR≥0.75, but epicardial LS was not; and that the whole-layer and endocardial LS had a modest diagnostic efficiency in identifying LV-segments perfused by vessels with an FFR<0.75.

Consistencies of 3D TTE global longitudinal strain of both ventricles between assessors were worse for 2D, but better for 3D ventricular EF

PURPOSE We evaluated the consistency of different-assessors in estimating three-dimensional (3D) global-longitudinal-strain (GLS) of left (LV) and right ventricle (RV) using transthoracic-echocardiography (TTE) for LV and RV systolic-function. We compared results from two-independent-specialists using this-approach for 3D LV and RV parameters in a population with 74% hypertrophic-cardiomyopathy (HCM) patients. METHODS 58 patients (43 HCM (32 male; 62 ± 15 years) and 15 controls (5 male; 53 ± 22 years)) underwent TTE (Vivid-E9) to measure 2D and 3D GLS of the LV and RV by two-independent-specialists. RESULTS Consistencies of estimates of 3D LV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection-fraction (EF) between the two-assessors were 0.872 (3D LVEDV, P<0.001), 0.797 (3D LVESV, P<0.001), and 0.215 (3D LVEF, P=0.105). Consistencies of 2D and 3D LV GLS between two-assessors were 0.900 (2D LVGLS, P<0.001) and 0.874 (3D LVGLS, P<0.001). Consistencies of estimates of 3D RVEDV, RVESV, and RVEF between two assessors were 0.781 (3D RVEDV, P<0.001), 0.755 (3D RVESV, P<0.001), and 0.26 (3D RVEF, P=0.049). Consistencies of 2D and 3D GLS of whole RV and those of RV free wall only between two-assessors were 0.886 (2D GLS of whole RV, P<0.001), 0.687 (3D GLS of whole RV, P<0.001), 0.707 (2D GLS of RV free wall, P<0.001), and 0.630 (3D GLS of RV free wall, P<0.001). CONCLUSIONS Consistencies of independent-estimates of 3D GLS of the LV and RV using TTE between two-assessors were worse than for 2D GLS of the LV and RV, but better than for 3D LVEF and RVEF in a population with 74% HCM patients.

Inter- and intraobserver consistency in LV myocardial strain measurement using a novel multi-layer technique in patients with severe aortic stenosis and preserved LV ejection fraction.

BACKGROUND A new transthoracic echocardiography (TTE) technique allows multi-layer measurement of left ventricular (LV), endocardial, epicardial, and whole layer myocardial strain. We evaluated interobserver and intraobserver TTE reproducibility for 2D LV global longitudinal (GLS) and circumferential strain (GCS) estimates using data from severe aortic stenosis (AS) subjects with preserved LV ejection fraction (EF). METHODS Twenty severe AS subjects (11 male; mean age, 75±7years; LV EF >50%) underwent TTE (Vivid E9, GE Healthcare). Quantitative strain measurements of whole, endocardial, and epicardial layers were performed. GLS was defined as all 17 averaged LV segments, according to the American Heart Association classification. GCS was measured at the levels of the mitral valve, papillary muscle, and apex. RESULTS Interobserver correlation coefficients in whole, endocardial, and epicardial layers for GLS estimates were 0.81, 0.83, and 0.80, respectively, whereas those for GCS estimates were 0.38, 0.56, and 0.19, respectively, for the mitral valve, 0.44, 0.54, and 0.36, respectively, for the papillary muscle, and 0.55, 0.29, and 0.59, respectively, for the apex. Intraobserver correlation coefficients in whole, endocardial, and epicardial layers for GLS estimates were 0.97, 0.97, and 0.94, respectively, whereas those for GCS estimates were 0.86, 0.81, and 0.50 , respectively, for the mitral valve, 0.56, 0.72, and 0.28, respectively, for the papillary muscle, and 0.70, 0.69, and 0.62, respectively, for the apex. CONCLUSION In severe AS subjects with preserved LVEF, inter- and intra-observer TTE reproducibility in whole, endocardial, and epicardial layers were more consistent for 2D LV GLS than for 2D LVGCS.

Efficiency of quantitative longitudinal peak systolic strain values using automated function imaging on transthoracic echocardiogram for evaluating left ventricular wall motion: New diagnostic criteria and agreement with naked eye evaluation by experienced cardiologist

PURPOSE To evaluate the efficiency of automated function imaging (AFI) on transthoracic echocardiogram (TTE) for detecting left ventricular (LV) wall motion (LVWM) abnormalities, we compared longitudinal peak systolic strain (LPSS) measurements using AFI with naked eye TTE evaluations by experienced cardiologists and non-experienced residents. MATERIALS AND METHODS A total of 352 segments of LV myocardium from 22 consecutive subjects with LVWM abnormalities based on American Heart Association classifications (11 male, mean age 58 ± 14 years) on previous TTE (Vivid-7, GE) were evaluated. LPSS was measured using stored AFI data. Naked eye evaluation of LVWM was performed by 2 experienced cardiologists and 2 non-experienced residents. RESULTS AFI successfully tracked 342 (97%) of all segments (mean LPSS -14.8 ± 8.1%). A significant strong negative correlation was observed between LV ejection fraction using method of disks and global LPSS (R=-0.8974). Temporary AFI criteria of LPSS were normal <-12; hypokinesis -12-2; and akinesis >2. Of 342 segments, 239, 87, and 16 segments were diagnosed as normal, hypokinesis, and akinesis, respectively. Level of agreement and kappa coefficients between qualitative evaluation of LVWM by AFI temporary criteria and qualitative evaluation of LVWM by experienced cardiologist 2 (0.784 and 0.479, respectively) were inferior to those comparing experienced cardiologists (0.845 and 0.595) but superior comparing experienced cardiologist with non-experienced resident (0.696 and 0.323), and between the 2 non-experienced-residents (0.682 and 0.347). CONCLUSION Qualitative evaluation of LVWM using temporary AFI criteria had a 97% success rate and agreed well with findings of an experienced cardiologist. AFI can be a useful tool for training residents.

Resting multilayer 2D speckle-tracking TTE for detection of ischemic segments confirmed by invasive FFR part-2, using post-systolic-strain-index and time from aortic-valve-closure to regional peak longitudinal-strain

PURPOSE This study evaluated the post-systolic strain index (PSI), and the time interval between aortic valve closure (AVC) and regional peak longitudinal strain (PLS), measured by transthoracic echocardiography (TTE), for detection of left ventricular (LV) myocardial ischemic segments confirmed by invasive fractional flow reserve (FFR). MATERIALS AND METHODS 39 stable patients (32 males; 65.8±11.9years) with 46 coronary arteries at ≥50% stenosis on invasive coronary angiography underwent 2D speckle tracking TTE (Vivid E9, GE Healthcare) and invasive FFR measurements. PSI, AVC and regional PLS in each LV segment were calculated. RESULTS FFR ≤0.80 was detected in 27 LV segments. There were no significant differences between segments supplied by FFR ≤0.80 and FFR >0.80 vessels in either PSI or the time interval between AVC and regional PLS. To identify LV segments±FFR ≤0.80, the receiver operator characteristic (ROC) curves for PSI, and the time interval between AVC and regional PLS had areas under the curve (AUC) values of 0.58 and 0.57, respectively, with best cut-off points of 12% (sensitivity 70.4%, specificity 57.9%) and 88ms (sensitivity 70.4%, specificity 52.6%), respectively, but the AUCs were not statistically significant. CONCLUSION In stable coronary artery disease patients with ≥50% coronary artery stenosis, measurement of PSI, and the time interval between AVC and regional PLS, on resting TTE, enabled the identification of LV segments with FFR ≤0.80 using each appropriate threshold for PSI, and the time interval between AVC and regional PLS, with reasonable diagnostic accuracy. However, the AUC values were not statistically significant.

Better agreement between independent assessors of three-dimensional global longitudinal strain of whole right ventricle using transthoracic echocardiography than for other three-dimensional right ventricular parameters.

a Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan b Department of Molecular Diagnosis, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan c Department of Respirology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba 260-8670, Japan

Quantitative Differentiation of LV Myocardium with and without Layer-Specific Fibrosis Using MRI in Hypertrophic Cardiomyopathy and Layer-Specific Strain TTE Analysis

To achieve further risk stratification in hypertrophic cardiomyopathy (HCM) patients, we localized and quantified layer-specific LVM fibrosis on MRI in HCM patients using regional layer-specific peak longitudinal strain (PLS) and peak circumferential strain (PCS) in LV myocardium (LVM) on speckle tracking transthoracic echocardiography (TTE). A total of 18 HCM patients (14 males; 58 ± 17 years) underwent 1.5T-MRI and TTE. PLS and PCS in each layer of the LVM (endocardium, epicardium, and whole-layer myocardium) were calculated for 17 AHA-defined lesions. MRI assessment showed that fibrosis was classified as endocardial, epicardial, or whole-layer (= either or both of these). Regional PLS was smaller in fibrotic endocardial lesions than in non-fibrotic endocardial lesions (P = 0.004). To detect LV endocardial lesions with fibrosis, ROC curves of regional PLS revealed an area under the curve (AUC) of 0.609 and a best cut-off point of 13.5%, with sensitivity of 65.3% and specificity of 54.3%. Regional PLS was also smaller in fibrotic epicardial lesions than in non-fibrotic epicardial lesions (P < 0.001). To detect LV epicardial lesions with fibrosis, ROC curves of PLS revealed an AUC of 0.684 and a best cut-off point of 9.5%, with sensitivity of 73.5% and specificity of 55.5%. Using whole-layer myocardium analysis, PLS was smaller in fibrotic lesions than in non-fibrotic lesions (P < 0.001). To detect whole-layer LV lesions with fibrosis, ROC curves of regional PLS revealed an AUC of 0.674 and a best cut-off point of 12.5%, with sensitivity of 79.0% and specificity of 50.7%. There were no significant differences in PCS of LV myocardium (endocardium, epicardium, and whole-layer) between fibrotic and non-fibrotic lesions. Quantitative regional PLS but not PCS in LV endocardium, epicardium, and whole-layer myocardium provides useful non-invasive information for layer-specific localization of fibrosis in HCM patients.