Non-Doppler two dimensional strain imaging for evaluation of coronary artery disease

Real-time three-dimensional echocardiography and two-dimensional speckle tracking imaging in the evaluation of left atrial function in patients with triple-vessel coronary artery disease without myocardial infarction

OBJECTIVE

To evaluate left atrial function in patients with triple-vessel disease (TVD) without myocardial infarction by real-time three-dimensional echocardiography (RT-3DE) and two-dimensional speckle tracking imaging (2D-STE).

METHODS

Sixty patients with coronary artery disease (CAD) without myocardial infarction were classified into two groups in accordance with the coronary angiography results: group B (all triple-vessel stenosis ≥ 50% and < 75%) and group C (all triple-vessel stenosis ≥ 75%). Thirty healthy individuals were selected as group A. LA volume related parameters including left atrial maximum volume index (LAVImax), LA passive and active ejection fraction (LAPEF, LAAEF) and LA total ejection fraction (LATEF) were measured by RT-3DE. The global peak atrial longitudinal systolic strain (LASRs), early and late diastolic LA strain (LASRe and LASRa) rates were measured by 2D-STE.

RESULTS

We found statistically significant differences between 2D-STE and RT-3DE related parameters of these three groups. Furthermore, in groups B and C, N-terminal fragment brain natriuretic peptides (NT-pro-BNP) and left ventricular end-diastolic pressure (LVEDP) were found to be significantly correlated with LASRs and LASRa. And NT-pro-BNP had a moderate correlation with LVEDP.

CONCLUSIONS

2D-STE and RT-3DE can assess the LA function in patients with TVD without myocardial infarction. And LA strain values may provide additional information for predicting increased LVEDP and NT-pro-BNP.

Longitudinal strain measured by two-dimensional speckle tracking echocardiography to evaluate left ventricular function in patients with myocardial bridging of the left anterior descending coronary artery

OBJECTIVES

Myocardial bridging (MB) can cause myocardial ischemia, myocardial infarction, or even sudden cardiac death. We aimed to evaluate the left ventricular function in patients with MB of the left anterior descending coronary artery (LAD) using longitudinal strain (LS) measured by two-dimensional speckle tracking echocardiography.

METHODS

We enrolled 46 subjects with MB in the LAD diagnosed by coronary angiography. Patients were categorized into two groups according to the severity of tunneled artery stenosis: <50% as group I (23 patients) and ≥50% as group II (23 patients). Twenty-five gender- and age-matched subjects without MB confirmed by coronary angiography or with normal results on treadmill exercise test were included as controls. Two-dimensional strain software was applied to measure the territories systolic average peak LS of the LAD coronary artery (LAD-TPLS), right coronary artery (RCA-TPLS), and left circumflex coronary artery (LCX-TPLS) and to measure the global systolic peak LS of left ventricle (LV-GPLS).

RESULTS

The ratio of mitral peak early (E) and late (A) filling velocity (E/A) and the average mitral annular velocity (e') were lower, and the mitral E/e' ratio was higher in group II than in group I and controls (P < 0.05). LV-GPLS and LAD-TPLS were significantly less negative in group II than in group I and controls (LV-GPLS: -19.77 ± 1.60% vs -21.10 ± 1.91% and -21.76 ± 1.23%; LAD-TPLS: -19.24 ± 2.22% vs -22.00 ± 2.22% and -22.74 ± 1.82%, P < 0.001). The systolic compression severity of the tunneled artery was significantly correlated with LAD-TPLS (r = -0.56, P < 0.001), but less strongly correlated with LV-GPLS (r = -0.40, P < 0.05). The area under the curves of LAD-TPLS was larger than that of LV-GPLS; a cutoff value for LAD-TPLS of -21.68% had 91.3% sensitivity and 73.9% specificity for detection of ≥50% of the tunneled artery stenosis.

CONCLUSIONS

In patients with ≥50% systolic narrowing of the tunneled artery, left ventricular systolic function and diastolic function were impaired, and the LAD-TPLS is an excellent predictor of ≥50% systolic narrowing of the tunneled artery in patients with MB of the LAD.

Assessment of left and right atrial geometrical changes in patients with stable coronary artery disease: Left and right atrial strain and strain rate imaging study

Objective

In patients with coronary artery disease (CAD), there are several studies that assessed the left ventricular (LV) function by strain (S) and strain rate (SR) imaging. The aim of this study is to evaluate the function of both atria in patients with CAD using strain and strain rate imaging, and to correlate this with the severity of CAD.

Methods

We conducted a prospective, single center case control study for 40 consecutive patients who presented to our department with chronic stable angina and were candidates for invasive coronary angiography. We enrolled patients from December 2013 to May 2014 and each patient was subjected to echocardiographic assessment of E/e' of mitral valve, left atrial volume index (LAVI), right atrial volume index (RAVI), and peak atrial longitudinal strain (es) and strain rate (SR) during LV systole. This was followed by invasive coronary angiography for assessment of the severity of CAD using Gensini score. Patients were classified according to angiographic results into 3 groups: Group I (Gensini score = zero), Group II (Gensini score > 0 and < 20) and Group III (Gensini score ≥ 20).

Results

There was no statistically significant difference between the three groups in either LA volumes (V_min, V_max) and distensibility with p value of 0.272, 0.126, and 0.243 respectively or RA volumes and distensibility with a p value of 0.671, 0.183, and 0.259 respectively. On the other hand, LA & RA systolic S and SR were significantly lower among CAD patients in comparison with the group of normal coronaries. Mean LA S and SR was decreased in group III than group II (15.97 ± 3.73, 21.8 ± 6.75 % and 1.11 ± 0.30, 1.81 ± 1.23 s^-1) with p value of 0.005&0.041 respectively. RA systolic S and SR were significantly lower in the 2 groups with CAD than the group with normal coronaries with a p value of 0.001 and 0.002 respectively.

Conclusion

In patients with CAD and normal EF, borderline E/e' ratio and normal atrial size, there are decreased LA and RA systolic S and SR parameters with no effect on atrial volumes or distensibility. Accordingly, this could prove that atrial wall deformation occurs early in CAD even before any changes in atrial volumes or dimensions.

Speckle tracking analysis in intensive care unit: A toy or a tool?

The use of conventional echocardiography in the intensive care unit (ICU) is today established to assess left and right ventricular systolic function, for preload determination and procedural guidance. Next step in ICU echocardiography could be the use of novel ultrasound techniques such as strain echocardiography to assist in the management of patients with acute coronary syndrome, heart failure, or pulmonary embolism. This review has gathered the available evidence supporting the incremental value of strain in the diagnostic workup of cardiac diseases treated in ICU.

Detection of left atrial dysfunction with speckle tracking echocardiography

BACKGROUND

The aim of this study was to evaluate the relationship between the SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) score and left ventricular end-diastolic pressure (LVEDP) measured with an invasive method and with speckle-tracking echocardiography (STE).

METHODS

The study included 124 patients who underwent cardiac catheterization. LVEDP values and coronary images were obtained for all patients. SYNTAX scores were calculated and separated into three tertiles (SYNTAX = 0, SYNTAX < 22, and SYNTAX > 22). Standard echocardiography and STE were performed on all the patients. Peak LA strain (LAs strain) in ventricular end-systole and LA strain during LA contraction (LAa strain) values were obtained with STE.

RESULTS

In univariate analysis, a strong correlation was observed between the SYNTAX score and LAs strain and a moderate correlation with LAa strain. A moderate correlation was also found between both LAs strain and LAa strain and LVEDP. In multiple regression analysis, LAs strain and LVEDP were observed to be independent predictors of SYNTAX score.

CONCLUSION

LAs strain and LVEDP were observed to be independent predictors of SYNTAX scores. The relationship between LAs strain, LVEDP, and SYNTAX score could be useful in clinical practice.

Measuring age-dependent myocardial stiffness across the cardiac cycle using MR elastography: A reproducibility study

PURPOSE

To assess reproducibility in measuring left ventricular (LV) myocardial stiffness in volunteers throughout the cardiac cycle using MR elastography (MRE) and to determine its correlation with age.

METHODS

Cardiac MRE (CMRE) was performed on 29 normal volunteers, with ages ranging from 21 to 73 years. For assessing reproducibility of CMRE-derived stiffness measurements, scans were repeated per volunteer. Wave images were acquired throughout the LV myocardium, and were analyzed to obtain mean stiffness during the cardiac cycle. CMRE-derived stiffness values were correlated to age.

RESULTS

Concordance correlation coefficient revealed good interscan agreement with rc of 0.77, with P-value < 0.0001. Significantly higher myocardial stiffness was observed during end-systole (ES) compared with end-diastole (ED) across all subjects. Additionally, increased deviation between ES and ED stiffness was observed with increased age.

CONCLUSION

CMRE-derived stiffness is reproducible, with myocardial stiffness changing cyclically across the cardiac cycle. Stiffness is significantly higher during ES compared with ED. With age, ES myocardial stiffness increases more than ED, giving rise to an increased deviation between the two.

Menopausal cardiomyopathy: does it really exist? A case-control deformation imaging study

AIM

We aimed to evaluate and compare the left ventricular (LV) functions of pre- and postmenopausal women at similar ages with none of the known cardiovascular risk factors, by both conventional and advanced echocardiographic methods such as 2-D strain imaging via speckle tracking echocardiography.

METHODS

The study population consisted of 40 healthy postmenopausal women aged 45-50 years and 40 healthy premenopausal women of the same age group. None of the subjects had any cardiovascular risk factors and were on hormone replacement therapy. LV strain and strain rate parameters were measured by 2-D strain imaging. The main outcome measure was effect of menopause on LV function.

RESULTS

There were no significant differences between the pre- and postmenopausal groups with regard to conventional echocardiographic parameters. LV longitudinal strain and LV early diastolic strain rate values were significantly lower in the postmenopausal group when compared to the premenopausal group. Also, there was a significant negative correlation between LV global strain and serum follicle-stimulating hormone (r = -0.349, P = 0.002).

CONCLUSION

Our study results demonstrated that healthy postmenopausal women had lower LV longitudinal strain values when compared to the healthy premenopausal women of the same age group by speckle tracking echocardiography.

Two-Dimensional Strain Imaging: Basic principles and Technical Consideration

Tissue Doppler Imaging (TDI) and TDI-derived strain provide considerably accurate information in the non-invasive assessment of local myocardial functions. Given its high temporal and spatial resolution, TDI allows assessment of local myocardial functions in each phase of cardiac cycle. However, the most important limitation of this method is its angle dependence. New techniques to measure myocardial deformation, such as speckle tracking echocardiography, overcome the angle-dependence limitation of TDI-derived strain. Moreover, these techniques provide more unique information about myocardial fiber orientation. This review examines the architectural structure and function of the myocardium and includes technical revisions of this information that will provide a basis for STE.

Characterization of aging-associated cardiac diastolic dysfunction

AIMS

Diastolic dysfunction is common in geriatric heart failure. A reliable parameter to predict myocardium stiffness and relaxation under similar end-diastolic pressure is being developed. We propose a material and mathematical model for calculating myocardium stiffness based on the concept of linear correlation between [Formula: see text] and wedge pressure.

METHODS AND RESULTS

We enrolled 919 patients (male: [Formula: see text][Formula: see text]). Compared with the younger population of controls (mean age: [Formula: see text] years; [Formula: see text]; male: [Formula: see text] [Formula: see text]), the elderly (mean age: [Formula: see text]; [Formula: see text]; male: [Formula: see text] [Formula: see text]) had a greater prevalence of hypertension, diabetes mellitus, and coronary artery disease (all [Formula: see text]). We collected their M-mode and 2-D echocardiographic volumetric parameters, intraventricular filling pressure, and speckle tracking images to establish a mathematical model. The feasibility of this model was validated. The average early diastolic velocity of the mitral annulus assessed using tissue Doppler imaging was significantly attenuated in the elderly ([Formula: see text]: [Formula: see text] vs. [Formula: see text]; [Formula: see text]) and corresponded to the higher estimated wedge ([Formula: see text]) pressure ([Formula: see text] vs. [Formula: see text]; [Formula: see text]) in that cohort. E (Young's modulus) was calculated to describe the tensile elasticity of the myocardium. With the same intraventricular filling pressure, E was significantly higher in the elderly, especially those with [Formula: see text] values [Formula: see text]. Compared with diastolic dysfunction parameters, E also presented sentinel characteristics more sensitive for detecting early myocardial relaxation impairment, which indicates stiffer myocardium in aging hearts.

CONCLUSION

Our material and geometric mathematical model successfully described the stiffer myocardium in aging hearts with higher intraventricular pressure. Additional studies that compare individual differences, especially in health status, are needed to validate its application for detecting diastolic heart failure.

Emerging role of echocardiographic strain/strain rate imaging and twist in systolic function evaluation and operative procedure in patients with aortic stenosis

Systolic function of the left ventricle is vital for patients with aortic stenosis. Unfortunately, the most widely used clinical parameter, the left ventricular ejection fraction, is not sensitive enough, especially for patients with left ventricular hypertrophy. Echocardiographic strain/strain rate and twist are emerging parameters for left ventricular systolic and diastolic function evaluation. Aortic stenosis could reduce strain/strain rate while magnifying twist. Furthermore, strain/strain rate correlates well with the prognosis of patients with aortic stenosis. Most importantly the circumferential strain, strain rate and twist also play a role in differentiating cardiac compensation or decompensation. In any case, these parameters could normalize after successful surgical aortic valve replacement or transcatheter aortic valve replacement. Regardless of these advantages, clinical evidence is needed to ensure their usefulness.

Left atrial and right atrial deformation in patients with coronary artery disease: a velocity vector imaging-based study

Background

Impaired left ventricular (LV) function has been shown by strain rate (SR) imaging in patients with coronary artery disease (CAD). Our aim was to investigate global and regional, systolic and diastolic left atrial (LA) and right atrial (RA) longitudinal deformation in CAD using velocity vector imaging.

Methods

Echocardiographic and velocity vector imaging studies were performed in 20 patients with mild CAD, 40 patients with severe CAD and 25 controls. Maximal atrial volume, peak atrial longitudinal strain (ε_s) and SR during LV systole (SRs), SR during early LV filling (SRe) and late LV filling (SRa) were measured. Longitudinal strain during atrial contraction (ε_a) was obtained at the onset of P-wave on electrocardiography, and ε_a/ε_s was calculated.

Results

Longitudinal peak ε_s and SRs of LA showed decreased trend among CAD patients. The global and lateral LA SRe were prominently lower, while RA ε_a, SRa and ε_a/ε_s were prominently higher in 2 CAD groups than control group (P value <0.05). As compared with controls and patients with other single-vessel disease, LA SRa and ε_a/ε_s ratio were significantly increased among patients with exclusively left anterior descending coronary artery (LAD) stenosis (SRa 1.14±0.38 s⁻¹, 1.10±0.41 s⁻¹, 1.45±0.46 s⁻¹, P value<0.05; ε_a/ε_s 0.44±0.11, 0.44±0.20, 0.57±0.12, P value<0.01).

Conclusions

Apparently decreased SRe of LA and increased ε_a, SRa and ε_a/ε_s of RA were found in CAD patients with preserved LVEF and E/E' in gray zone. SRa and ε_a/ε_s of LA were found to significantly increase in those with LAD stenosis.

Correlation between left ventricular global and regional longitudinal systolic strain and impaired microcirculation in patients with acute myocardial infarction

OBJECTIVES

We investigated the correlation between left ventricular global and regional longitudinal systolic strain (GLS and LRS) and coronary flow reserve (CFR) assessed by transthoracic echocardiography (TTE) in patients with a recent acute myocardial infarction (AMI). Furthermore, we investigated if LRS and GLS imaging is superior to conventional measures of left ventricle (LV) function.

METHODS

In a consecutive population of first time AMI patients, who underwent successful revascularization, we performed comprehensive TTE. GLS and LRS were obtained from the three standard apical views. Assessment of CFR by TTE was performed in a modified apical view using color Doppler guidance.

RESULTS

The study population consisted of 183 patients (51 females) with a median age of 63 [54;70] years. Eighty-nine (49%) patients had a non-ST elevation myocardial infarction and 94 (51%) patients had a ST elevation myocardial infarction. The GLS was -15.2 [-19.3;-10.1]% in the total population of 183 patients. Total wall motion score index (WMSI) in the population was 1.19 [1;1.5]. Eighty-five patients suffered from culprit lesion in left anterior descending artery (LAD). The CFR in these patients was 1.86 [1.36;2.35] and the GLS was -14.3 [-18.9; -9.8]%. A significant difference was observed in the LRS in LAD territory in culprit LAD infarction patients with a CFR ≤ 2 (-9.6 [-13.77;-6.44]) compared with the LRS in LAD territory in culprit LAD infarction patients with a CFR > 2 (-19.33 [-21.1;-16.5]), P < 0.0001. We found no significant difference between WMSI in LAD territory in culprit LAD infarction patients with a CFR ≤ 2 (1.56 [1.06;2.23]) compared with WMSI in LAD territory in culprit LAD infarction patients with a CFR > 2 (1.37 [1.03;2.11]); P = 0.18. The same pattern was observed in both circumflex coronary artery (CX) and right coronary artery (RCA) territories. In the total population, we found a strong correlation between CFR and GLS (r = -0.85, P < 0.0001). This was also seen in the multivariate regression model adjusting for possible confounders including WMSI (P < 0.001).

CONCLUSION

In this study, we have shown a close association between myocardial deformation in patients with a recent AMI and the degree of diminished microcirculation. We found that both GLS and LRS correlated with CFR. We conclude that GLS and LRS are significantly better tools to assess impaired CFR and LV function after a recent AMI, than conventional echocardiographic measurements.

Efficacy of longitudinal speckle tracking strain in conjunction with isometric handgrip stress test for detection of ischemic myocardial segments

BACKGROUND

Isometric handgrip stress test is a simple method for detecting coronary artery disease (CAD). However, the value of this method alone is limited by relatively low sensitivity. This study thus aimed to investigate the usefulness of two-dimensional speckle-tracking strain combined with handgrip for CAD patients.

METHOD

We studied 35 patients with stable angina pectoris who underwent percutaneous coronary intervention (PCI). Longitudinal (L-ɛ) and transverse peak systolic (T-ɛ) strains were measured from three standard apical views before and 1 month after PCI. Segments corresponded to perfusion territories of coronary arteries were divided into two groups based on coronary angiography results: stenotic (S) and nonstenotic (NS) segment.

RESULTS

L-ɛ in S segments increased significantly after PCI, from -15.8% to -17.6% (P < 0.01), but not in NS segments. Moreover, L-ɛ in S segments increased significantly during handgrip before PCI, from -15.8% to -17.6% (P < 0.01), but decreased after PCI, from -17.6% to -16.7% (P = 0.02). In contrast, L-ɛ in NS segments decreased significantly during the isometric handgrip stress test before and after PCI (P < 0.05). Especially noteworthy is that a relative change in L-ɛ of >1.2% during handgrip before PCI could detect significant coronary stenosis with a sensitivity of 80%, specificity of 66%, and area under the curve of 0.77 (P < 0.001). On the other hand, no significant changes were observed in either T-ɛ segments during handgrip either before or after PCI.

CONCLUSION

Longitudinal speckle-tracking strain combined with handgrip may constitute a valuable tool for detection of ischemic myocardial segments and prediction of improvement of regional contraction after revascularization.

Application of speckle-tracking echocardiography in detecting coronary artery disease in patients with maintenance hemodialysis

BACKGROUND

Satisfactory and noninvasive diagnostic tools for coronary artery disease (CAD) are not available in hemodialysis patients. We aimed to elucidate a reliable tool to diagnose CAD in these patients.

METHODS

102 hemodialysis patients received 2D speckle-tracking echocardiography with left ventricular (LV) strain analysis and blood tests for cardiac troponin T, high-sensitive C-reactive protein, interleukin (IL)-6, and IL-18.

RESULTS

The levels of biomarkers did not differ between patients with and without CAD. The factors associated with CAD were decreased circumferential strain, decreased global longitudinal strain, and the number of LV segments with decreased longitudinal strain. Logistic regression analyses showed that the number of LV segments with decreased longitudinal strain, over 6 segments, was strongly associated with CAD in hemodialysis patients (OR 12.08, 95% CI 3.724-39.209).

CONCLUSIONS

The noninvasive modality of speckle-tracking echocardiography with strain analysis is efficient and objective for identifying CAD in hemodialysis patients.

Echocardiographic strain imaging and its use in the clinical setting

The use of echocardiography has grown tremendously over the past several years. It is used routinely for diagnosis, prognosis and monitoring changes of cardiac function in coronary artery disease, heart failure, pulmonary hypertension, arrhythmias, pericardial disease and valvular disease, as well as congenital conditions. In recent years, the advancing technology used to evaluate the heart by ultrasound has allowed physicians to understand the mechanics of the heart muscle and the contribution of abnormalities in myocardial movement to heart disease. This review will discuss novel echocardiographic strain imaging techniques, placing them in the context of myocardial mechanics and describing current and future applications.

Exploring oligodendrocyte guidance: 'to boldly go where no cell has gone before'

Oligodendrocytes, the myelinating cells of the central nervous system (CNS), originate early in the formation of the brain in specific foci, and migrate throughout the parenchyma. The instructional cues guiding the migration of these progenitor cells must be encoded into their developing environment. Soluble factors as well as membrane-bound cues most likely synergize to create a complex thoroughfare needed to sculpt and organize the brain into a functional organ with white and gray matter. Classically, the focus of many guidance related studies in the CNS has been limited to neuron physiology. However, It is becoming increasingly clear that their lifelong partners, oligodendrocytes, express both ligands and receptors able to both present and respond to these classical cues. In this short review, some recent findings in the Semaphorin and Eph fields will be presented with respect to oligodendrocyte expression and function.