Left atrial deformation analysis as a predictor of severity of coronary artery disease

Incremental prognostic utility of left ventricular and left atrial strains in coronary artery disease patients with reduced systolic function

OBJECTIVE

This study aimed to investigate the predictive value of left ventricular global longitudinal strain (GLS) and left atrial reservoir strain (LARS) on adverse events in chronic coronary artery disease (CAD) patients with reduced systolic function.

METHODS

A total of 192 consecutive patients clinically diagnosed with chronic CAD and left ventricular ejection fraction (LVEF) ≤ 50% were finally included. Multiple strain parameters were analyzed with speckle tracking echocardiography. The composite endpoint included all-cause mortality, rehospitalization due to heart failure, myocardial infarction, and stroke.

RESULTS

Patients experiencing the endpoint showed lower LVEF, lower absolute GLS and LARS than those without events. Both GLS (AUC = 0.82 [GLS] vs. 0.58 [LVEF], p < 0.001) and LARS (AUC = 0.71 [LARS] vs. 0.58 [LVEF], p = 0.033) were superior to LVEF in predicting adverse events. Multivariate cox regression analysis showed that both GLS (hazard ratio, 0.71; 95% CI, 0.63-0.79; p < 0.001) and LARS (hazard ratio, 0.96; 95% CI, 0.93-0.98; p < 0.001) were independent predictors for the endpoint. The addition of LARS (global chi-squared, 35.7 vs. 17.4; p < 0.05), GLS (global chi-squared, 58.6 vs. 17.4; p < 0.05) or both LARS and GLS (global chi-squared, 79.6 vs. 17.4; p < 0.05) to LVEF in the prediction model significantly improved its performance. The same significant improvement was also shown in the subgroups of mild (30% < LVEF ≤ 50%) and severe (LVEF ≤ 30%) reduced systolic function.

CONCLUSIONS

Regarding CAD patients with reduced LVEF, both GLS and LARS are superior to LVEF in predicting adverse events, providing significant incremental value to LVEF.

Coronary artery disease is associated with impaired atrial function regardless of left ventricular filling pressure

BACKGROUND

Left atrial (LA) strain is impaired in left ventricular (LV) diastolic dysfunction, associated with increased LV end diastolic pressure (LVEDP). In patients with preserved LV ejection fraction (LVEF), coronary artery disease (CAD) is known to impair LV diastolic function. The relationship of LVEDP with CAD and impact on LA strain is not well studied.

METHODS AND RESULTS

Patients with LVEF >50% (n = 37, age 61 ± 7 years) underwent coronary angiography, high-fidelity LV pressure measurements and cardiac magnetic resonance imaging. LA volumes, LA emptying fraction (LAEF), LA reservoir strain (LARS) and LA long-axis shortening (LALAS) were measured. By coronary angiography, patients were assigned into 3 groups: severe-CAD (n = 19, with obstruction of major coronary arteries >70% and/or history of coronary revascularization), mild-to-moderate-CAD (n = 10, obstruction of major coronary arteries 30-60%), and no-CAD (n = 8, obstruction of major coronary arteries and branches <30%). Overall, LVEF was 65 ± 8% and LVEDP was 14.4 ± 5.6 mmHg. Clinical characteristics, LVEDP and LV function measurements were similar in 3 groups. Severe-CAD group had lower LAEF, LALAS and LARS than those in no-CAD group (P < 0.05 all). In regression analysis, LARS and LALAS were associated with CAD severity and treatment with Nitrates, whereas LAEF and LAEFactive were associated with CAD severity, treatment with Nitrates and LA minimum volume (P < 0.05 all). LAEFpassive was associated with LVED volume (P < 0.05).

CONCLUSIONS

LA functional impairment may be affected by coexistent CAD severity, medications, in particular, Nitrates, and loading conditions, which should be considered when assessing LA function and LA-LV interaction. Our findings inspire exploration in a larger cohort.

Machine learning-enhanced echocardiography for screening coronary artery disease

BACKGROUND

Since myocardial work (MW) and left atrial strain are valuable for screening coronary artery disease (CAD), this study aimed to develop a novel CAD screening approach based on machine learning-enhanced echocardiography.

METHODS

This prospective study used data from patients undergoing coronary angiography, in which the novel echocardiography features were extracted by a machine learning algorithm. A total of 818 patients were enrolled and randomly divided into training (80%) and testing (20%) groups. An additional 115 patients were also enrolled in the validation group.

RESULTS

The superior diagnosis model of CAD was optimized using 59 echocardiographic features in a gradient-boosting classifier. This model showed that the value of the receiver operating characteristic area under the curve (AUC) was 0.852 in the test group and 0.834 in the validation group, with high sensitivity (0.952) and low specificity (0.691), suggesting that this model is very sensitive for detecting CAD, but its low specificity may increase the high false-positive rate. We also determined that the false-positive cases were more susceptible to suffering cardiac events than the true-negative cases.

CONCLUSIONS

Machine learning-enhanced echocardiography can improve CAD detection based on the MW and left atrial strain features. Our developed model is valuable for estimating the pre-test probability of CAD and screening CAD patients in clinical practice.

TRIAL REGISTRATION

Registered as NCT03905200 at ClinicalTrials.gov. Registered on 5 April 2019.

Four-dimensional quantification on left atrial volume-strain in coronary heart disease patients without regional wall motion abnormalities: Correlation with the severity of coronary stenosis

OBJECTIVE

Echocardiography is a time and cost-effective imaging modality, providing evidence of myocardial ischemia by detecting the regional wall motion abnormalities (RWMA). However, quite a few coronary heart disease (CHD) patients do not present RWMA. The left atrium (LA) plays an irreplaceable role in determining the prognosis and risk stratification of cardiovascular disease including CHD. In this present study, we intend to explore the myocardial mechanics changes of LA mainly using four-dimensional (4D) LA quantitative volume-strain in CHD patients without RWMA at rest but were confirmed by coronary angiography (CAG) and to figure out several variables of the LA that could contribute to the identification of those patients.

METHODS

We prospectively enrolled 76 patients who underwent two-dimensional echocardiography (2DE), four-dimensional echocardiography (4DE), and CAG for suspected CHD but without echocardiographic visible RWMA at rest. Patients diagnosed with CHD by CAG were furtherly divided into three groups according to the extent of coronary stenosis accessed by Gensini score (GS) as the mild, moderate, and severe CHD group. Twenty-four subjects with negative CAG results served as the control group. LA end-systolic anteroposterior diameter (LAAPD) and biplane LV ejection fraction (Biplane LVEF) were measured by 2DE; LA maximum volume (LAVmax), LA minimum volume (LAVmin), LA volume at the onset of atrial contraction (LAVpreA), LAVmax index (LAVmaxI), LA ejection volume (LAEV), LA ejection fraction (LAEF) accompanied by LA longitudinal strain during reservoir phase (LASr), conduit phase (LAScd), contraction phase (LASct) and LA circumferential strain during reservoir phase (LASr_c), conduit phase (LAScd_c), contraction phase (LASct_c) were measured by 4DE automatically. We compared these parameters between groups, explored how they change and whether they are related to the CHD severity.

RESULTS

LAEF, LASr_c, and LASct_c was lower in CHD group compared with the control group (p = .031, .002, .004, respectively). Pearson correlation analysis showed that LASr, LASct, LASr_c, and LASct_c negatively correlated with the GS. Additionally, LASr of patients in the severe CHD group decreased significantly compared with those in the mild CHD group, moderate CHD group, and control group, demonstrating the highest area under the receiver operating characteristic (ROC) curve (AUC) (AUC = .736 [p = .003, 95% CI .589-.884], sensitivity 67.8%, specificity 70.6%) with the cut-off value of 17.5% for predicting severe CHD patients.

CONCLUSION

Four-dimensional LA strain may provide new insight into identification and management for CHD patients and correlate with CHD severity. LASr showed good sensitivity (67.8%) and specificity (70.6%) for diagnosing severe CHD individuals.

Determinants of the Volumetric Markers of Left Atrial Contraction Function in Coronary Artery Disease: A Cross-sectional Study

BACKGROUND

A body of research advocates the prognostic role and usefulness of the volumetric markers of left atrial (LA) phasic functions in the diagnosis of LA dysfunction. We aimed to determine the independent determinants of the volumetric markers of LA contraction function in candidates for coronary artery bypass graft (CABG) surgery.

METHODS

This cross-sectional study enrolled 516 candidates for CABG. The biplane maximal, minimal, and pre-P volumes of the LA were measured with two-dimensional echocardiography, and LA active emptying fraction was calculated. The standardized correlation coefficient for the correlation between each factor and LA active emptying fraction was calculated by using univariate and backward multivariable regression analyses.

RESULTS

The multivariable regression analysis demonstrated that the heart rate (β = 0.15; p = 0.001), S (β = 0.09; p = 0.036), E/e′ ratio (β = −0.11; p = 0.014), left ventricle (LV) ejection fraction (β = 0.15; p = 0.001), and LA enlargement (β = −0.19; p < 0.001) were the independent determinants of LA active emptying fraction.

CONCLUSIONS

The independent determinants of LA contraction function were the heart rate, S, LV ejection fraction, LA enlargement, and E/e′ ratio in candidates for CABG surgery.

Contemporary narrative review on left atrial strain mechanics in echocardiography: cardiomyopathy, valvular heart disease and beyond

Left atrial (LA) strain mechanics refer to the measurement of LA myocardial deformation expressed as a percentage, and have been gathering interest over the last decade with expanding research supporting their utility in multiple cardiovascular disorders. Measured through advanced dynamic imaging techniques which include tissue Doppler imaging (TDI) and two-dimensional (2D) speckle tracking echocardiography (STE), LA strain mechanics are affected by left ventricular diastolic dysfunction prior to the onset of functional and structural changes in the left ventricle (LV). There is a need for practising cardiologists to become more familiar with the clinical utility of LA strain mechanics. In this article, we begin by reviewing the physiologic function of the LA, using this as a basis for understanding LA strain mechanics. The focus of this review article is to provide a contemporary update on the utility of LA strain mechanics in a range of cardiovascular disorders, including atrial fibrillation (AF), hypertrophic cardiomyopathy (HCM), valvular pathologies, coronary artery disease (CAD) as well as systemic diseases, such as hypertension (HTN), obesity and diabetes mellitus (DM). This article also highlights the current limitations in more widespread clinical applications of LA strain mechanics, as well as outlining the future perspectives on the clinical applications of LA strain mechanics.

Speckle Tracking Echocardiography: Early Predictor of Diagnosis and Prognosis in Coronary Artery Disease

Echocardiography represents a first level technique for the evaluation of coronary artery disease (CAD) which supports clinicians in the diagnostic and prognostic workup of these syndromes. However, visual estimation of wall motion abnormalities sometimes fails in detecting less clear or transient myocardial ischemia and in providing accurate differential diagnosis. Speckle tracking echocardiography (STE) is a widely available noninvasive tool that could easily and quickly provide additive information over basic echocardiography, since it is able to identify subtle myocardial damage and to localize ischemic territories in accordance to the coronary lesions, obtaining a clear visualization with a "polar map" useful for differential diagnosis and management. Therefore, it has increasingly been applied in acute and chronic coronary syndromes using rest and stress echocardiography, showing good results in terms of prediction of CAD, clinical outcome, left ventricular remodeling, presence, and quantification of new/residual ischemia. The aim of this review is to illustrate the current available evidence on STE usefulness for the assessment and follow-up of CAD, discussing the main findings on bidimensional and tridimensional strain parameters and their potential application in clinical practice.

New Ultrasound Technologies for Ischemic Heart Disease Assessment and Monitoring in Cardiac Rehabilitation

Owing to its ease of application, noninvasive nature, and safety, echocardiography is an essential imaging modality to assess cardiac function in patients affected by ischemic heart disease (IHD). Over the past few decades, we have witnessed a continuous series of evolutions in the ultrasound field that have led to the introduction of innovative echocardiographic modalities which allowed to better understand the morphofunctional abnormalities occurring in cardiovascular diseases. This article offers an overview of some of the newest echocardiographic modalities and their promising application in IHD diagnosis, risk stratification, management, and monitoring after cardiac rehabilitation.