Role of Cardiovascular Ultrasound in the Evaluation of Obese Subjects

Epicardial Adipose Tissue in Patients with Coronary Artery Disease: A Meta-Analysis

Objective: The aim of this study is to assess the association between epicardial adipose tissue (EAT) and coronary artery disease (CAD) via meta−analysis. Methods: Specific searches of online databases from January 2000 to May 2022 were conducted. All observational studies evaluating the association between EAT and CAD in PubMed, Web of Science, and the Cochrane Library databases were screened. A meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta−Analyses guidelines (PRISMA). In total, 21 studies encompassing 4975 subjects met the inclusion criteria, including 2377 diagnosed and assigned as the CAD group, while the other 2598 were assigned as the non−CAD group. Subjects in the CAD group were further divided into the severe stenosis group (stenosis ≥ 50%, n = 846) and the mild/moderate stenosis group (stenosis < 50%, n = 577). Results: Both the volume and thickness of EAT in the CAD group were larger compared to the non−CAD group (p < 0.00001). In a subgroup analysis within the CAD group, the severe stenosis group had a larger volume and thickness with respect to EAT when compared to the mild/moderate group (p < 0.001). Conclusions: The enlargement of EAT presented in CAD patients with an association with CAD severity. Although limited by different CAD types and measuring methods for EAT, as well as a smaller sample size, our results suggest that EAT is a novel predictor and a potential therapeutic target for CAD.

Association between Isometric and Allometric Height-indexed Left Atrial Size and Atrial Fibrillation

BACKGROUND

Height-based indexations for evaluation of left atrial (LA) volumes have been proposed as an alternative method to account for body stature when body composition is abnormal. We sought to derive reference values for these indexation methods, and to examine their association to atrial fibrillation (AF).

METHODS

A healthy population was randomly split into a derivation and validation cohort (n=493 each). The derivation cohort was used to derive reference values for iso- and allometric height-indexed LA volumes. Echocardiography included measurement of maximal and minimal LA volume (LAV_max and LAV_min, respectively). Association between these measures and AF was investigated in the validation cohort. Cox proportional hazards regression was performed adjusting for CHARGE-AF risk score.

RESULTS

From 986 healthy subjects, allometric height-indexed exponents were determined to 1.72 and 1.56 for LAV_max and LAV_min, respectively. Upper reference values were determined to LAV_max>22.1mL/m^1.72 and LAV_min>12.7mL/m^1.56. In the validation cohort, 41 (8%) developed AF during follow-up (median: 14.7 years). In unadjusted analyses, both isometric and allometrically indexed LAV_max were associated with AF (HR=1.07 (1.03-1.11), p<0.001 and HR=1.11 (1.05-1.18), p<0.001, per 1-ml/m and 1-ml/m^1.72 increase respectively) with equal C-statistics of 0.63. Height-indexed LAV_min was also associated with AF with higher C-statistics than LAV_max. All findings were consistent after multivariable adjustment. LAV_max>22.1mL/m^1.72 posed an increased risk of AF (HR=4.65 (1.83-11.86)), however, LAV_min>12.7mL/m^1.56 carried a higher risk (HR=6.33 (2.66-15.07)).

CONCLUSION

Both Isometric and allometrically height-indexed LA volumes are associated with AF in the general population. LAV_min is more strongly associated with AF than LAV_max regardless of indexation.

Epicardial fat and coronary artery disease: Role of cardiac imaging

Epicardial adipose tissue (EAT) represents the fat depot located between the myocardium and the visceral pericardial layer. Far from being an inert tissue, EAT has been recognized as secreting a large amount of bioactive molecules called adipokines, which have numerous exocrine and paracrine effects. Recent evidence demonstrates that pericoronary adipose tissue (PCAT) - the EAT directly surrounding the coronary arteries - has a complex bidirectional interaction with the underlying vascular wall. While in normal conditions this mutual cross-talk helps maintain the homeostasis of the vascular wall, dysfunctional PCAT produces deleterious pro-inflammatory adipokines involved in atherogenesis. Importantly, PCAT inflammation has been associated with coronary artery disease (CAD) and major cardiovascular events. This review aims to provide an overview of the imaging techniques used to assess EAT, with a specific focus on cardiac computed tomography (CCT), which has become the key modality in this field. In contrast to echocardiography and cardiac magnetic resonance (CMR), CCT is not only able to visualize and precisely quantify EAT, but also to assess the coronary arteries and the PCAT simultaneously. In recent years, several papers have shown the utility of using CCT-derived PCAT attenuation as a surrogate measure of coronary inflammation. This noninvasive imaging biomarker may potentially be used to monitor patient responses to new antinflammatory drugs for the treatment of CAD.

Obesity, Cardiac Remodeling, and Metabolic Profile: Validation of a New Simple Index beyond Body Mass Index

Aim:

The body mass index (BMI), the most used anthropometric index of obesity, has an important limitation, not taking into consideration the distribution of body fat. We developed a new simple index: the waist-corrected BMI (wBMI), calculated as waist circumference (WC) × BMI. The study aim was to assess the role of wBMI, compared to BMI, WC, and Waist-to-Height Ratio (WHtR) in predicting abnormal cardiac geometry, insulin resistance, increased arterial stiffness, and dyslipidemia.

Methods:

This was a cross-sectional study that included 805 patients referred to our Department of Preventive Cardiology for risk factors evaluation and treatment. Eleven echographic and laboratory parameters were determined, and receiver operating characteristic (ROC) curves were derived. Areas under ROC curves (AUC) were used to assess the accuracy of the four indexes to identify unfavorable characteristics.

Results:

There were 29% overweight, 59% obese, and 77% hypertensive patients. Of 11 echographic and laboratory parameters, wBMI, BMI, WHtR, and WC had the largest AUC for identifying 3, 1, 6, and 1 parameters, respectively, but with overlapping 95% confidence intervals. wBMI had the largest AUC for increased arterial stiffness and insulin resistance; also, it was superior to BMI for increased left atrial volume, relative wall thickness, and triglyceride level.

Conclusions:

In a large population with a high prevalence of obesity and hypertension, all four indexes were associated with unfavorable characteristics. wBMI has the theoretical advantage of taking into account simultaneously the global fat mass and distribution and might be useful for a better cardiovascular risk assessment.

The Association of Left Ventricular Mass Index with Metabolic Syndrome in Comparison to Hypertensive Patients

BACKGROUND AND OBJECTIVES

The metabolic syndrome (MS) is a condition associated with the clustering of risk factors including high blood pressure (BP), abdominal obesity, glucose intolerance, and dyslipidemia; which increases cardiovascular morbidity and mortality. High burden of subclinical disease component of MS contributes to the increased risk by causing left ventricular (LV) hypertrophy, thereby affecting long-term prognosis. This cross-sectional study uncovers the role of LV hypertrophy (LVH) and LV mass index (LVMI) in patients with MS in comparison to hypertensive patients.

SUBJECTS AND METHODS

A total of fifty North Indians, out of which 25 subjects were cases with the MS (obesity, dyslipidemia, glucose intolerance/diabetes with hypertension) and rest of the 25 subjects were control with hypertensive patients were included in the study and assessed for LVH and LVMI by two-dimensional echocardiography. Data were analyzed by SPSS version 21.0 based program.

RESULTS

MS cases had a significantly higher mean LVMI (49.60 ± 21.23 g/m^2.7) (P < 0.05), also higher exposure rate of LVH with 11 cases (44%) and relative risk of 1.38 (odds ratio 1.67, 95% confidence interval 0.53-5.29) than controls with hypertensive patients. Among LVH patients, mean LVMI was highest in MS cases with males (50.31 ± 26.03 g/m^2.7), high body mass index >30 kg/m² (51.14 ± 22.08 g/m^2.7), FBS ≤ 140 mg/dl (53.72 ± 27.91 g/m^2.7), high TG > 150 mg/dl (50.00 ± 22.09 g/m^2.7), and low HDL (male <40, female <50 mg/dl) (57.22 ± 27.23 g/m^2.7) than controls with hypertension; respectively (P > 0.05, not significant).

CONCLUSION

MS, as a clustering of cardiovascular risk factors, is associated with higher LVM and prevalence of LVH. Therefore, high BP, increased waist circumference, dyslipidemia, and hyperglycemia separately and additively contributes to LVH suggesting that optimal BP control along with weight loss, lipid lowering agents, and euglycemic state may contribute to regression of LVH and LVM.