New echocardiographic techniques in the evaluation of left ventricular function in obesity

Obesity: the perfect storm for heart failure

Obesity condition causes morphological and functional alterations involving the cardiovascular system. These can represent the substrates for different cardiovascular diseases, such as atrial fibrillation, coronary artery disease, sudden cardiac death, and heart failure (HF) with both preserved ejection fraction (EF) and reduced EF. Different pathogenetic mechanisms may help to explain the association between obesity and HF including left ventricular remodelling and epicardial fat accumulation, endothelial dysfunction, and coronary microvascular dysfunction. Multi-imaging modalities are required for appropriate recognition of subclinical systolic dysfunction typically associated with obesity, with echocardiography being the most cost-effective technique. Therapeutic approach in patients with obesity and HF is challenging, particularly regarding patients with preserved EF in which few strategies with high level of evidence are available. Weight loss is of extreme importance in patients with obesity and HF, being a primary therapeutic intervention. Sodium-glucose co-transporter-2 inhibitors have been recently introduced as a novel tool in the management of HF patients. The present review aims at analysing the most recent studies supporting pathogenesis, diagnosis, and management in patients with obesity and HF.

Cardiovascular Imaging in Obesity

Obesity represents one of the most challenging public health problems of our century. It accounts for approximately 5% of deaths worldwide, mostly owing to cardiovascular disease and its associated complications. Cardiovascular noninvasive imaging may provide early accurate information about hypertrophy and ischemia/fibrosis in obese subjects. Echocardiography and nuclear cardiology have serious limitations in obese subjects owing to poor acoustic window and attenuation artifacts, respectively. Coronary computed tomography angiography can provide information about obstructive coronary disease; however, the use of radiation is a serious disadvantage. Finally, cardiac magnetic resonance (CMR) holds the promise of an "all in one" examination by combining evaluation of function, wall motion/thickness, stress rest/perfusion, replacement and diffuse fibrosis without radiation. Future studies are required to document the cost/benefit ratio of the CMR in the evaluation of cardiovascular risk in overweight/obese children and adolescents.

[Adipose epicardial tissue association with subclinical systolic dysfunction detected by longitudinal strain in diabetic patients with poor glycemic control]

OBJECTIVE

The aim of this study is to assess the association between epicardial adipose tissue (EAT) and infraclinical myocardial dysfunction detected by strain imaging in diabetic patients (T2DM) with poor glycemic control.

METHODS

22 patients with T2DM and 22 healthy control subjects of similar age and sex were prospectively recruited. Echocardiographic parameters were investigated.

RESULTS

In comparison to controls, diabetic patients had significantly higher body mass index (27.7 vs. 24.6; P<0.01), waist perimeter (103 vs. 84; P<0.001) and usCRP level (5.4 vs. 1.5; P<0.01). On echocardiography; no differences were found in terms of ejection fraction or ventricular mass; however, patients with T2DM had significantly thicker EAT (8.7±0.7 vs. 3.0±1.0; P<0.001) and altered systolic longitudinal strain (-18.8±3.2 vs. 22.3±1.6; P<0.001). On multivariate analysis, EAT was identified as an independent contributor (β=0,46, P=0.001) to systolic longitudinal strain.

CONCLUSION

In patients with T2DM and poor glycemic control; EAT was associated with infraclinical systolic dysfunction evaluated by global longitudinal strain despite normal at rest ejection fraction and no coronary artery disease.

Prevalence and determinants of left ventricular diastolic dysfunction in obese subjects and the role of left ventricular global longitudinal strain and mass normalized to height

BACKGROUND

Left ventricular (LV) diastolic dysfunction (DD) is a frequent finding in obesity and may predispose to the development of heart failure (HF). However, no data are available on the prevalence of DD after the introduction of the 2016 Recommendations of the American Society of Echocardiography and the European Association of Cardiovascular Imaging.

METHODS AND RESULTS

To assess the impact of the new Recommendations on the prevalence of DD and on their clinical and echocardiographic correlates in obesity, a prospective study was performed in 588 subjects with an ejection fraction (EF) ≥50% and no history of HF either obese (n = 402; mean age: 47 ± 12 years; women 71%; body mass index [BMI]: 44 ± 8 kg/m² ), overweight (n = 86; BMI: 28 ± 1 kg/m² ), or with a normal weight (n = 100; BMI: 22 ± 2 kg/m² ). All subjects underwent an echocardiographic and Doppler study, including the assessment of global longitudinal strain (GLS). DD occurred in 19% of obese patients, 12% of overweight subjects, and 2% of normal weight subjects. We used multivariable logistic analysis to assess the risk of DD. In patients with BMI ≥30 kg/m² , LV mass normalized to height (2.7) (OR: 1.04, P = .0028), and GLS (OR: 0.85, P = .0032) were associated with an increased risk of DD followed by EF (OR: 0.91, P = .045), diabetes (OR: 1.91, P = .065), and systolic blood pressure (OR: 1.02, P = .076).

CONCLUSION

These results show that DD is highly prevalent among obese subjects and impairment of longitudinal systolic mechanics, as reflected by GLS reduction, and LV mass normalized to height are major independent predictors of DD in this patients' population.

Subclinical Myocardial Impairment in Metabolic Diseases

Type 2 diabetes mellitus (T2DM) and obesity are important contributors to nonischemic heart failure (HF) and atrial fibrillation. There is a 2- to 5-fold increase in HF associated with T2DM, and there is a 5% in HF risk in men and 7% increment in women for every unit increment in body mass index, after adjustment for traditional cardiovascular risk factors. Likewise, the risk of atrial fibrillation increases by about 6% per unit increase in body mass index. Metabolic cardiomyopathy leads to a number of changes in cardiac structure and function that can be recognized by imaging in the asymptomatic phase, and these parameters can be used for monitoring the progression of disease or the response to therapy. The purpose of this review is to familiarize clinicians with the potential benefits of early detection of preclinical myocardial abnormalities, as well as the mechanisms that might inform interventions to prevent disease progression in patients with T2DM and obesity.

The Impact of Obesity on the Cardiovascular System

Obesity is a growing health problem worldwide. It is associated with an increased cardiovascular risk on the one hand of obesity itself and on the other hand of associated medical conditions (hypertension, diabetes, insulin resistance, and sleep apnoea syndrome). Obesity has an important role in atherosclerosis and coronary artery disease. Obesity leads to structural and functional changes of the heart, which causes heart failure. The altered myocardial structure increases the risk of atrial fibrillation and sudden cardiac death. However, obesity also has a protective effect on the clinical outcome of underlying cardiovascular disease, the phenomenon called obesity paradox. The improved cardiac imaging techniques allow the early detection of altered structure and function of the heart in obese patients. In this review, we attempt to summarize the relationship between obesity and cardiovascular diseases and outline the underlying mechanisms. The demonstrated new techniques of cardiac diagnostic procedures allow for the early detection and treatment of subclinical medical conditions and, therefore, the prevention of cardiovascular events.

Young Women With Abdominal Obesity Have Subclinical Myocardial Dysfunction

BACKGROUND

Abdominal obesity is an independent risk factor for cardiovascular disease. The effect of abdominal obesity on myocardial function in young obese women remains unknown. Therefore, we aimed to investigate cardiac morphology and function, myocardial deformation, and mechanical indices, in young women with and without abdominal obesity.

METHODS

Cross-sectional analyses of 39 women with abdominal obesity (waist circumference ≥ 80 cm) and 33 nonobese control subjects (waist circumference < 80 cm) aged 18-30 years underwent conventional echocardiographic measures of cardiac morphology and function together with tissue Doppler, and 2-dimensional speckle tracking measures of myocardial deformation and mechanics. Cardiometabolic risk factors including anthropometric, hypertension, biochemistry, and fitness were also assessed.

RESULTS

Standard echocardiography results for cardiac morphology and function were similar between groups, with the exception of larger left atrial dimensions in women with abdominal obesity (P ≤ 0.05). Compared with control subjects, women with abdominal obesity also demonstrated reduced systolic and diastolic mitral annular plane velocities, increased left atrial pressure surrogates (E/diastolic mitral annular plane velocity), and prolonged timing measures of diastolic function including isovolumic relaxation time and transmitral deceleration time (P ≤ 0.05). In addition, longitudinal strain and diastolic strain rate were reduced in women with abdominal obesity (P ≤ 0.05) but circumferential deformation and myocardial mechanics (twist indices and rotation) were preserved. Markers of abdominal obesity retained an independent direct correlation with parameters of cardiac dysfunction, explaining 12%-39% of the overall variability.

CONCLUSIONS

A young, otherwise healthy group of women with abdominal obesity displayed subclinical cardiac dysfunction indicated using selected tissue Doppler imaging and speckle tracking echocardiography measures.

Role of Cardiovascular Ultrasound in the Evaluation of Obese Subjects

Obesity represents a worldwide increasing health problem. Obesity, through complex and not fully understood pathogenetic mechanisms, induces different structural and functional changes of left heart chambers, right heart chambers, and arteries. Ultrasound techniques are the first choice for a comprehensive assessment of the cardiovascular adaptation to obesity. This review summarizes the up-to-date literature on the topic, with particular focus on the main clinical studies, which range over different cardiovascular adaptations to obesity, namely left ventricular mass, diastolic function, right ventricle structure and function, arterial stiffness, and intima-media thickness. Also, the importance of epicardial fat and of the degree of obesity is described. Finally, the role of weight loss and bariatric surgery and the study of cardiovascular obesity-induced abnormalities in children and adolescent are discussed.

Early Detection of Left Ventricular Dysfunction in Diabetes Mellitus Patients with Normal Ejection Fraction, Stratified by BMI: A Preliminary Speckle Tracking Echocardiography Study

Background:

Diabetes mellitus (DM) represents by itself a major risk factor for cardiovascular events and the coexistence of obesity with consequent left ventricular volumetric overload could be responsible for further damages on left ventricular function. Aim of this study was to demonstrate the effect of body mass index (BMI) on left ventricular function in diabetes patients with no cardiovascular complications and with normal ejection fraction (EF).

Materials and Methods:

We evaluated 71 stable asymptomatic diabetes patients in optimal medical treatment and 24 healthy controls (C) (45% females; mean age: 58.4 +/− 9.4 years; BMI: 23.5 +/− 1.5). We stratified diabetes patients into two groups according to BMI: BMI <30 kg/m² (A: 44 patients; 47% females; mean age: 60.9 +/− 6.6 years; BMI: 25.7 +/− 1.9; Diabetes duration: 9.1 +/− 9.5 years); BMI >30 kg/m² (B: 27 patients; 37% females; mean age: 56.2 +/− 7.8 years; BMI: 33.0 +/− 2.1; Diabetes duration: 8.5 +/− 5.2 years). The following parameters were evaluated by conventional two dimensional (2D) echocardiography (GE VIVID 7) and tissue Doppler imaging (TDI): left ventricular dimensions (LVIDd; PWTd; IVSd), Left Ventricular Volumes (EDV, ESV), EF (by biplane Simpson’s method), Left Ventricular Mass (by ASE formula), peak mitral annular velocity at septal and lateral levels (Sm and Sl). Global longitudinal strain (GLS) was obtained off line by Speckle tracking imaging method using Echopac 10 software.

Results:

Groups A, B were comparable for diabetes duration and glycated hemoglobin level, history of hypertension, and lipid profile. The EF was similar in the three groups, (A: 64 +/− 6%; B: 63 +/− 4%; C: 61 +/−5%; P= NS). LVMass^2.7 indexed for height was significantly higher in A and B in comparison with C (A: 45.2 +/− 8.1 g/m^2.7; B: 46.1 +/− 9.6 g/m^2.7; C: 39.5 +/− 4.9 g/m^2.7; P < 0.05). The stroke volume index (SVi) was significantly lower in B vs A (B: 35.3 +/− 5.7 ml/m²; A: 39.3 +/7.1 ml/m²; P = 0.033). GLS was significantly lower in group B respect A and C (C: 20.9 +/− 1.3%; A: -20.3+/−2.6%; B: -19 +/− 2; P < 0.05; P < 0.01).

Conclusions:

In uncomplicated asymptomatic DM patients, the presence of first degree obesity plays an incremental role in adversely affecting left ventricular function and remodeling. The conventional echocardiographic methods such as the EF and the TDI are not so sensitive to identify the early LV dysfunction such as the evaluation of GLS by Speckle Tracking echocardiography. The longitudinal subendocardial fibers dysfunction in diabetes/obese patients could be derived by the complex interaction between metabolic (diabetes) and hemodynamic/endocrine abnormalities.