Relationship between preclinical abnormalities of global and regional left ventricular function and insulin resistance in severe obesity: a Color Doppler Imaging Study

Abstract

Background: The aim of this study was to evaluate the relationship between insulin resistance and preclinical abnormalities of the left ventricular structure and function detected in severe obesity by Color Doppler Myocardial Imaging (CDMI). Forty-eight consecutive severely obese patients (Group O) (11 males, 37 females, mean age 32.877 years) were enrolled. Forty-eight sexand age-matched non-obese healthy subjects were also recruited as controls (Group C). All subjects underwent conventional 2D-Color Doppler echocardiography and CDMI. The homeostasis model assessment insulin resistance index (HOMA-IR) was used to assess insulin resistance results. Obese subjects had a greater left ventricular mass index (by height) (58.8714 g/m 2.7 ) than controls (3778 g/m 2.7 ) (Po0.0001), owing to compensation response to volume overload caused by a greater cardiac output (Po0.02). Preload reserve was increased in obese subjects, as demonstrated by a significant increase in left atrial dimension (Po0.0001). Obese patients had a slightly reduced LV diastolic function (transmitral E/A ratio: Group O, 1.170.8 vs Group C, 1.5 70.5; Po0.002). Cardiac deformation assessed by regional myocardial systolic strain and strain rate (SR) values was significantly lower (abnormal) in obese patients than in controls, both at the septum and lateral wall level. These strain and SR abnormalities were significantly related to body mass index. In addition, the early phase of diastolic function, evaluated using SR, was compromised in obese patients (Po0.001). The HOMA-IR values in obese patients were significantly higher (3.0971.6) than those determined in the control group (0.9270.5) (Po0.0001). The HOMA-IR values, in the obese group, were significantly related to systolic strain and SR values sampled at the septum level (Po0.0001). Conclusion: In conclusion, this study has demonstrated that obese patients pointed out systolic structural and functional abnormalities at a preclinical stage, in particular through strain and SR analysis; on the other hand, those altered CDMI parameters well distinguish obese subjects as compared with the control group. Furthermore, another main finding of the study was that myocardial deformation (systolic strain) could have a correlation with insulin resistance level.

Effect of Obesity on Left Ventricular Longitudinal Myocardial Strain by Speckle Tracking Echocardiography in Children and Adolescents

“…These strain imaging parameters appear to be related to the severity of obesity and can contribute to increased BMI. Furthermore, our results are similar to the previous study of results (6,7,30 Di Bello et al (30) evaluate the regional myocardial function in obese adult patients (n=48; mean age, 32.8 years) and showed that systolic strain and SR values were lower in the obese group than the controls, both at the septum and lateral wall level. It was reported by Lorch et al (2) that decreased diastolic dysfunction in obese children have recorded using the strain parameters (early diastolic SR and SR E/A ratios ) in the LV septal and lateral walls.…”

“…The STE-derived strain parameter is a relatively new parameter that is used to assess systolic and diastolic myocardial function (11,13,30). Obese subjects also had higher risk of a pseudonormalized diastolic pattern.…”

“…Up to this time, studies on 2D speckle tracking strain has a limited number of studies in obese children. It is clear that this method is useful in obesity (7,13,30). Previous studies of obesity LV function to show subclinical abnormalities was used color Doppler strain or 2D speckle tracking strain (7,8,11,13,(18)(19)(20)30).…”

Cardiac Remodeling in Obesity

“…However, few clinical studies of global LV function have taken into account either myocardial afterload or preload 74,76 (Table 1). The strain studies thus far published have used Doppler, 73,81,86 myocardial systolic and diastolic velocities, 67 or both 82 ( Figure 6), and velocity vector imaging to investigate LV twist and rotation. These studies consistently demonstrate lower levels of strain, velocities, strain rates, and torsion in obese patients with normal EF, compared with the control subjects.…”

Improvement of left ventricular function by lifestyle intervention in obesity: contributions of weight loss and reduced insulin resistance

“…The public health ramifications are considerable, as obesity is an established risk factor for the development of heart failure, with effects on cardiovascular morbidity and mortality rates independent of commonly associated co-morbidities, such as coronary artery disease, hypertension and diabetes mellitus [3]. Subclinical left ventricular dysfunction is a common finding in overweight patients [4,5] and may progress over time to overt heart disease. As weight excess and insulin resistance are considered to mediate the link between obesity and cardiac function [5,6], successful strategies for weight reduction and improvement in metabolic status could improve left ventricular performance.…”