Longitudinal Strain by Automated Function Imaging Detects Single-Vessel Coronary Artery Disease in Patients Undergoing Dipyridamole Stress Echocardiography

Evolution of Stress Echocardiogram in the Era of CT Angiography

The ideal diagnostic modality for acute chest pain is a highly debated topic in the cardiovascular community. With the rapid rise of coronary computed tomography angiography (CTA) and the fall of functional testing, stress echocardiography (SE) is at a delicate crossroads. Though there are many advantages of coronary CTA, it is not without its flaws. The exact realm of SE needs to be clearly defined, as well as which patients need diagnostic testing. The emergence of additional parameters will propel the evolution of modern SE. In this review article, we explore the role of SE, guidelines, comparison of SE versus CTA, and additional parameters in the coronary CTA era.

Assessment of Postsystolic Shortening and Global Longitudinal Strain Improves the Sensitivity of Dobutamine Stress Echocardiography in End-Stage Liver Disease

BACKGROUND

Dobutamine stress echocardiography (DSE) remains a widely used method for detection of coronary artery disease (CAD) in patients with end-stage liver disease (ESLD) despite low sensitivity. Speckle-tracking assessment of strain may enhance the sensitivity of DSE in the general population, but the value of strain analysis in ESLD is unknown.

METHODS

Dobutamine stress echocardiography with two-dimensional speckle-tracking and quantitative coronary angiography were performed in 146 patients with ESLD. Thirty-six patients (25%) had CAD (≥50% diameter stenosis of a major vessel). Global longitudinal strain at rest (GLSr) and at peak stress (GLSp) and an index of postsystolic (PSSi) shortening ([maximal extent of shortening - extent of shortening in systole]/[extent of shortening in systole]) were determined. A PSSi of ≥ 0.25 was considered evidence for CAD. Receiver operating characteristic analysis was used to determine the optimal thresholds of GLSr and GLSp for CAD and to assess the diagnostic performance of visual assessment of wall motion (WMA) and strain parameters. The sensitivity and specificity of WMA, GLSr, GLSp, and PSSi were compared.

RESULTS

Thirty-six patients (25%) had significant CAD. The areas under the curve for WMA, GLSr, GLSp, and PSSi were 0.60, 0.72, 0.68, and 0.78, respectively. Visual assessment of wall motion had a sensitivity of 28%. The sensitivity of each of the strain parameters, GLSr (53%, P = .016), GLSp (69%, P = .004), and PSSi (78%, P < .001), exceeded the sensitivity for WMA. Visual assessment of wall motion specificity was 92%, which exceeded the specificity for each of the strain parameters (GLSr = 82%, P = .037; GLSp = 63%, P < .001; and PSSi =78%, P = .009). Of the strain parameters, PSSi had the best balance between sensitivity and specificity (both 78%).

CONCLUSION

Assessment of GLS and PSSi with DSE yields better sensitivity than WMA in ELSD patients. Index of postsystolic shortening had the best diagnostic performance of all parameters in this population with a low prevalence of CAD.

Preliminary Feasibility of Stress Myocardial Elastography for the Detection of Coronary Artery Disease

Myocardial elastography (ME) is a cardiac strain imaging technique that has been found capable of detecting a decrease in radial strain caused by ischemia or infarction in patients with coronary artery disease (CAD) as well as in a canine model. Prior studies have focused on rest imaging, but stress testing can reveal functional deficits caused by stenoses that are asymptomatic at rest. Therefore, it has been proposed that stress ME (S-ME) improves the detection of CAD. A novel strain difference (Δε) metric is presented and investigated in a canine model of induced ischemia, as well as in a study in human patients with CAD validated by myocardial perfusion imaging. In the canine model study, flow-limiting stenosis was induced by partial ligation in n = 2 canines, and stenosis was found to consistently reduce Δε in the affected myocardial regions compared with baseline, as well as compared to myocardial regions that are remote to the induced stenosis. In the clinical study, the median Δε was significantly lower (p < 0.05) in infarcted myocardial regions (-6.29%) than in those with normal perfusion (4.62%), with Δε in ischemic regions falling in between (-2.91%). The same trend was observed when considering radial strain during stress and, to a lesser degree, at rest alone. The results indicate that S-ME may be more sensitive to mild cases of CAD that are functionally asymptomatic at rest.

Comparison between Visual Assessment and Longitudinal Strain during Dobutamine Stress Echocardiography

Background

The relationship between visual assessment and longitudinal strain during dobutamine stress echocardiography (DSE) remains poorly investigated. This study assessed wall motion segments visually graded as normokinetic, hypokinetic, and akinetic at baseline and the peak of DSE and compared with longitudinal strain between segments with and without induced impaired contractility and improved contractility during DSE.

Methods

This study included 112 patients examined by DSE, consisting of 58 patients referred for diagnostic study and 54 patients referred for viability study. Regional left ventricular (LV) contractility was assessed visually and longitudinal strain was measured using echocardiography transthoracic.

Results

At baseline, the strain of LV segments was -16.33 ± 6.26 in visually normokinetic, 13.05 ± 6.44 in visually hypokinetic, and -8.46 ± 5.69 in visually akinetic segments. During peak dose, the strain of LV segments was -15.37 ± 6.89 in visually normokinetic, -11.37 ± 5.11 in visually hypokinetic, and -7.37 ± 3.92 in visually akinetic segments. In segments with visually observed impaired contractility, the median longitudinal strain was significantly lower than in segments without impaired contractility. For segments with visually observed improved contractility, the median longitudinal strain was significantly higher than for segments without improved contractility. In diagnostic study, sensitivity of visual assessment for absolute decrease of >2% longitudinal strain was 77%, respectively. In the viability study, the sensitivity was 82% for an absolute decrease of ≥2% longitudinal strain.

Conclusions

There is good association between strain analysis value and visually assessed wall motion contractility.

Prognostic value of two-dimensional strain in early ischemic heart disease: A 5-year follow-up study

INTRODUCTION

Two-dimensional strain echocardiography (2D-SE) is a reliable method for measuring deformation of the left ventricle.

AIM OF THE STUDY

Aim of the study was to determine changes in 2D-SE parameters over time collected during dipyridamole stress echo-cardiography (dipy-stress) and prognosis of patients with non-diagnostic dipy-stress results.

METHODS

In the first phase of the study, assessment of a prospective enrolled population with a non-diagnostic dipy-stress test result was conducted, checking through coronary CT angiography (CCTA) the presence of coronary artery disease (CAD). In the follow-up phase, an echocardiographic re-evaluation and outcome analysis during a mean follow-up of 78 months was carried out.

RESULTS

In the first phase, Global Circumferential Strain (GCS) values were similar in the CCTA positive and CCTA negative groups at rest and after stress. For Global Longitudinal Strain (GLS), there was a significant reduction (p < .0001) in the CCTA positive group compared to the CCTA negative group. After 78 ± 9 months none of the enrolled patients experimented cardiac events. Values of GCS, both at rest and after stress, did not differ statistically comparing follow-up values with baseline ones. No statistically significant changes were seen in the same analysis for GLS rest and stress values, between baseline and follow-up in the two groups.

CONCLUSIONS

Performing 2D-SE during dipy-stress can detect mild CAD that conventional stress-tests miss. Patients with mild coronary stenosis may have a favorable mid-term prognosis, but efforts should be made to investigate the decrease trend in GLS, at rest and after stress, reported in this patient group.

The feasibility, reliability, and incremental value of two-dimensional speckle-tracking for the detection of significant coronary stenosis after treadmill stress echocardiography

Background

Two-dimensional speckle-tracking echocardiography (STE) may help detect coronary artery disease (CAD) when combined with dobutamine stress echocardiography. However, few studies have explored STE with exercise stress echocardiography (ESE). We aimed to evaluate the feasibility, reliability, and incremental value of STE combined with treadmill ESE compared to treadmill ESE alone to detect CAD.

Methods

We conducted a case–control study of all consecutive patients with abnormal ESE in 2018–2020 who subsequently underwent coronary angiography within a six-month interval. We 1:1 propensity score-matched these patients to those with a normal ESE. Two blinded operators generated a 17-segment bull's-eye map of longitudinal strain (LS). We utilized the mean differences between stress and baseline LS values in segments 13–17, segment 17, and segments 15–16 to create receiver operator curves for the overall examination, the left anterior descending artery (LAD), and the non-LAD territories, respectively.

Results

We excluded 61 STEs from 201 (30.3%) eligible ESEs; 47 (23.4%) because of suboptimal image quality and 14 (7.0%) because of excessive heart rate variability precluding the calculation of a bull's-eye map. After matching, a total of 102 patients were included (51 patients in each group). In the group with abnormal ESE patients (mean age 66.4 years, 39.2% female), 64.7% had significant CAD (> 70% stenosis) at coronary angiogram. In the group with normal ESE patients (mean age 65.1 years, 35.3% female), 3.9% were diagnosed with a new significant coronary stenosis within one year. The intra-class correlation for global LS was 0.87 at rest and 0.92 at stress, and 0.84 at rest, and 0.89 at stress for the apical segments. The diagnostic accuracy of combining ESE and STE was superior to visual assessment alone for the overall examination (area under the curve (AUC) = 0.89 vs. 0.84, p = 0.025), the non-LAD territory (AUC = 0.83 vs. 0.70, p = 0.006), but not the LAD territory (AUC = 0.79 vs. 0.73, p = 0.11).

Conclusions

Two-dimensional speckle-tracking combined with treadmill ESE is relatively feasible, reliable, and may provide incremental diagnostic value for the detection and localization of significant CAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12947-021-00259-w.

Rapidly and Accurately Detecting Significant Coronary Artery Stenosis in Patients with Suspected Stable Coronary Artery Disease and Normal Segmental Wall Motion by Speckle Tracking Automated Functional Imaging

This study was performed to explore the value of a machine with built-in speckle tracking automated functional imaging (AFI) in predicting the severity of coronary artery lesions in patients with suspected stable coronary artery disease (SCAD) with normal wall motion. One hundred forty-three consecutive patients with clinically suspected SCAD with normal wall motion were included. Multiple parameters, including global longitudinal peak strain, post-systolic index (PSI) and peak strain dispersion, were automatically analyzed with AFI. Territorial longitudinal strain (TLS) and territorial PSI (TPSI) were also calculated. Receiver operating characteristic curve analyses revealed that global longitudinal peak strain and PSI were superior to other parameters in detecting left main or three-vessel SCAD. A combination of TLS and TPSI could improve diagnostic performance in identifying significant stenotic left anterior descending and right coronary arteries. In conclusion, 2-dimensional speckle tracking AFI can rapidly provide multiple parameters for detecting significant coronary artery stenosis with high accuracy in patients suspected of having SCAD with normal wall motion.

Myocardial strain indices and coronary flow reserve are only mildly affected in healthy hypertensive patients

To investigate changes in two-dimensional myocardial strain echocardiography (2DSTE) indices following a dipyridamole stress test (DIPSE) in relatively healthy hypertensive patients and healthy controls. Forty-seven male hypertensive patients (aged 57±9 years) with normal ejection fraction and without left ventricular (LV) hypertrophy and 20 healthy male subjects were studied with conventional and 2DSTE echocardiography at rest and post DIPSE. Coronary flow reserve (CFR) in the left anterior descending artery following DIPSE was also evaluated. Global longitudinal strain (GLS) and TWIST were higher while UNTWIST rate was lower in hypertensives versus controls (p < 0.05 for all); TWIST remained higher in hypertensives (p = 0.021) after adjustment for differences in age and body mass index (BMI) between the groups. CFR was higher in controls compared to hypertensives even after adjustment for confounders (4.14 vs. 2.53, p = 0.001). DIPSE-induced changes did not differ between the groups after adjustment for age and BMI (p > 0.05 for all). DIPSE-induced improvement in GLS was associated with higher CFR only in hypertensive patients (r - 0.372, p = 0.010). The current study showed that well controlled hypertensive patients have only mild echocardiographic differences compared to controls; some of these differences appear to depend on age and BMI. A 'hyper-rotation' phenomenon (i.e. higher TWIST) early in hypertension may be a compensatory mechanism to preserve global systolic LV function. Coronary microcirculatory function was impaired in hypertensive patients, albeit within normal range, and was associated with DIPSE-induced changes in myocardial long-axis systolic function.

Impaired coronary microcirculation is associated with left ventricular diastolic dysfunction in end-stage chronic kidney disease patients

INTRODUCTION

Coronary vascular dysfunction, as assessed by coronary flow reserve (CFR) in the left anterior descending coronary artery, is found in various conditions including end-stage chronic kidney disease (CKD). Currently, we investigated the associations of CFR with echocardiographic indices of systolic and diastolic cardiac function and identified independent predictors of CFR in hemodialysis patients.

METHODS

End-stage CKD patients treated with hemodialysis (n = 29) without known cardiovascular disease were recruited from a Hemodialysis Unit in Northwestern Greece. A thorough echocardiographic evaluation including CFR measurement following dipyridamole infusion was performed in all participants. Arterial stiffness was assessed by measurement of carotid-femoral pulse wave velocity and aortic augmentation index.

RESULTS

The mean age of the patients was 63 years, and mean duration of hemodialysis was 2.9 years. CFR was 1.60 ± 0.37 while dipyridamole caused a significant increase in E'_sep , S_lat , E'_lat , and Stroke volume (P < .05 for all). Independent predictors of CFR were posterior wall thickness (B -0.408, P = .013) and dipyridamole-induced changes in Tei index (B -0.425, P = .007). A severely decreased CFR < 1.5 was observed in 52% of the patients. E/E' ratio (B 10.84, P = .014) was the single independent predictor of severely decreased CFR.

CONCLUSIONS

In end-stage CKD patients on hemodialysis without known cardiovascular disease, impaired coronary vascular function was prevalent and related to increased left ventricular wall thickness, increased filling pressures, and dipyridamole-induced deteriorated myocardial function independently of the presence of wall-motion abnormalities. Further studies are required to clarify the prognostic role of dipyridamole-induced cardiac changes in hemodialysis patients.

The prognostic role of myocardial strain indices and dipyridamole stress test in renal transplantation patients

INTRODUCTION

Renal transplantation (RT) increases survival in end-stage kidney disease patients but cardiovascular diseases remain the leading cause of morbidity and mortality. We evaluated the role of myocardial strain (2DSTE) indices and dipyridamole-induced (DIPSE) changes in echocardiographic parameters at baseline for the prediction of clinical events and echocardiographically assessed deterioration of cardiac function in a RT population.

METHODS

Forty-five RT patients underwent an echocardiographic study at baseline including 2DSTE and DIPSE. If no cardiovascular/renal event occurred, patients were investigated at 3-year follow-up; eight patients presented a clinical event while 37 patients were re-evaluated.

RESULTS

Coronary flow reserve (CFR) was abnormal in 24% of the population. DIPSE induced improvements in classic and 2DSTE systolic and diastolic echocardiographic indices including TWIST, UNTWIST, global longitudinal strain (GLS), and circumferential strain (P < .05 for all). Compared to baseline, deteriorations in E/E', LVEF, E', and TWIST were observed at follow-up (P < .05 for all). DIPSE-induced changes in GLS, global radial strain, and LVEF were associated with changes in these indices at follow-up (P < .05 for all). Higher LV mass index, E/E', and lower MAPSE, E', and CFR at baseline were associated with the occurrence of clinical events at follow-up (P < .05 for all).

CONCLUSIONS

In RT patients, coronary vascular dysfunction (ie, low CFR) was associated with the occurrence of adverse events. DIPSE-induced changes in myocardial strain and classic echocardiographic indices could identify individuals with a subclinical deterioration in cardiac function at follow-up. This may indicate that DIPSE could serve as a means to assess myocardial reserve in this population.

Role of left ventricle deformation analysis in stress echocardiography for significant coronary artery disease detection: A diagnostic study meta-analysis

BACKGROUND

We compared the diagnostic accuracy of longitudinal strain (LS) imaging during stress echocardiography with visual assessment of wall motion (WM) for detecting significant coronary artery disease (CAD).

METHODS

Our systematic search included studies reporting diagnostic measures for LS imaging and visual assessment of WM for detecting significant CAD during stress echocardiography. Summary diagnostic accuracy measures including area under the curve (AUC), sensitivity, specificity, diagnostic odds ratio (DOR), and likelihood ratios (LRs) were estimated.

RESULTS

In thirteen studies with 978 patients, ten studies used invasive coronary angiography as the reference standard. Pooled AUC for diagnosing significant CAD was 0.92 (95% confidence interval [CI] 0.89-0.94) for LS imaging as compared to 0.83 (95% CI 0.80-0.86), P < 0.001 for visual assessment of WM. LS imaging had higher sensitivity (88% [95% CI 84-92] vs 74% [95% CI 68-80], P < 0.001) and comparable specificity to visual assessment of WM (80% [95% CI 72-87] vs 83% [95% CI 74-90], P = 0.592). The DOR for LS imaging and visual assessment of WM was 31 and 15, P = 0.254, respectively. The positive LR was 4.5 for both; negative LR was 0.14 and 0.31, P = 0.002 for LS imaging and visual assessment of WM, respectively.

CONCLUSIONS

Longitudinal strain imaging during stress echocardiography has better diagnostic accuracy for detecting significant CAD as compared to visual assessment of WM. Studies using larger sample size and standardized techniques of strain measurement are required to further ascertain the added advantage of strain measurement over visual assessment alone.

Ten Years of 2D Longitudinal Strain for Early Myocardial Dysfunction Detection: A Clinical Overview

In recent years, the role of left ventricular ejection fraction (EF) as the gold standard parameter for the evaluation of systolic function has been questioned, and many efforts have been concentrated in the clinical validation of new noninvasive tools for the study of myocardial contractility. Improvement in the accuracy of speckle-tracking echocardiography has resulted in a large amount of research showing the ability of two-dimensional strain to overcome EF limitations in the majority of primary and secondary heart diseases. Currently, global longitudinal strain (GLS) is considered the most accurate and sensitive parameter for the assessment of early left ventricular dysfunction. This review summarizes the advantages that this measurement can provide in several clinical settings. Moreover, the important cautions that should be considered in making the choice to use GLS also are addressed. Finally, a special focus on bull's-eye polar maps for the assessment of regional changes of longitudinal function and the usefulness of these maps in the differential diagnosis of several diseases is provided.

Stress Echocardiography: Need to Optimize its Appropriate Use in Suspected Angina and a Review of Available Additional Tools for its Clinical Application in 2018: First do no Harm! Second do it at the Highest Possible Accuracy

There is a need to reassess the most appropriate indications for stress echocardiography in the current era, in patients with suspect or known coronary artery disease (CAD), and also the most helpful additional parameters that can be easily calculated in clinical practice to increase the known suboptimal sensitivity for obstructive CAD of this test. The current review tries to clarify what is and what should be the proper role for functional testing in general, but specifically regarding modern stress echocardiography in the current practice, for suspected CAD and/or atypical chest pain. Few candidate additional parameters beyond wall motion assessment are here suggested to improve diagnostic accuracy of stress echocardiography, and pertinent literature is briefly reviewed, together with a more personal view of the author regarding the characteristics of each parameter, as far as ease of acquisition, cost, and true diagnostic or prognostic clinical usefulness are concerned. The reviewed additional parameters, which can be acquired during stress echocardiography, are Doppler coronary flow reserve in the left anterior descending artery, cardiac calcium score, global longitudinal strain, ventricular elastance, and contrast myocardial perfusion. Each of them finds a potential place in the current practice or may find a place in the future practice of stress echocardiography.

Strain Imaging with a Bull's-Eye Map for Detecting Significant Coronary Stenosis during Dobutamine Stress Echocardiography

BACKGROUND

Accurate visual assessment of wall motion during dobutamine stress echocardiography (DSE) requires expertise; strain stress echocardiography thus has potential for the objective and reliable evaluation of stress-induced wall motion abnormalities. The aim of this study was to test the hypothesis that strain imaging also requires expertise. Diagnostic accuracy for significant coronary artery disease was compared between visual and strain analysis with a bull's-eye map, and the effect of expertise on readers' accuracy during DSE was determined.

METHODS

Thirty-seven patients who underwent both DSE and coronary angiography within 6 months were retrospectively selected. Three experts and two fellows performed visual and two-dimensional speckle-tracking analysis using vendor-dependent (GE) software in three apical views. A bull's-eye map of longitudinal strain and a postsystolic shortening map were generated at baseline and peak stress. Significant coronary stenosis was defined as a >1% reduction in longitudinal strain with an increase in postsystolic shortening of at least two contiguous segments in the specific coronary artery territory at peak stress compared with baseline.

RESULTS

Twenty-five patients had significant coronary artery disease (>70% stenosis on coronary angiography), including 17 with left anterior descending coronary artery stenosis and 19 with non-left anterior descending coronary artery stenosis. Overall, strain imaging provided no additional benefit over visual analysis in detecting significant stenosis per patient and per vessel among experts and fellows. Strain analysis by the fellows had significantly lower specificity and accuracy compared with the experts.

CONCLUSIONS

Expertise affects strain evaluation for detecting significant coronary artery disease during DSE.

Diagnostic value of layer-specific global longitudinal strain during adenosine stress in patients suspected of coronary artery disease

Speckle tracking global longitudinal strain (GLS) from dobutamine stress echocardiography (SE) predicts coronary artery disease (CAD). The diagnostic value of GLS from vasodilator SE and the additional value of layer-specific speckle tracking analysis are unclear. We explored the usefulness of layer-specific GLS and non-layer-specific strain (automated functional imaging, AFI) from adenosine SE. The included 132 patients (67% male, 62.6 (9.0) years), of which 46 (35%) had CAD defined as ≥1 stenosis ≥70% (≥50% in the left main), underwent adenosine SE and invasive coronary angiography. Resting AFI and layer-specific GLS were similar in patients with or without CAD (p > 0.05). The stress-rest difference (Δvalue = stress-value - rest-value) in patients with CAD was less pronounced compared to patients without proved CAD (Δendocardial GLS: -1.2 (3.5)% vs. -5.0 (3.2)%; Δmidventricular GLS: -0.95 (3.0)% vs. -4.2 (2.7)%; Δepicardial GLS: -0.7 (2.5)% vs. -3.4 (2.3)%; ΔAFI: -0.8 (2.9)% vs. -3.6 (3.1)%, p < 0.00001 for all comparisons). The diagnostic value of the three layer-specific GLS values and AFI were statistically similar (p = 0.19). The four Δvalues provided independent predictive value to the risk assessment given by gender, age, wall motion and ΔEF (p = 0.002, AFI and p < 0.0001, layer-specific GLS). The accuracies were acceptable (71-80%) with modest sensitivities (54-65%) and high specificities (80-91%). The deformation response to vasodilator infusion was associated with the presence of CAD. Endocardial, midventricular and epicardial GLS and AFI from adenosine SE had similar diagnostic values. The specificities were high, but the modest sensitivities are a limitation to the clinical application.