Early cardiac dysfunction in obese adolescents with Down syndrome or autism

BACKGROUND

Obesity in adolescents with intellectual and developmental disabilities) occurs at twice the frequency as their typically developing peers. Typically developing adolescents with obesity have abnormal cardiac function (as measured by strain echocardiography) and cardiac mass, but the effects of obesity on cardiac health in adolescents with Down syndrome or autism spectrum disorder are unknown. The purpose of this study was to evaluate the impact of body mass index on cardiac function in adolescents with Down syndrome or autism.

METHODS

Adolescents (age 12-21 years) with Down syndrome (n = 28), autism (n = 33), and age-/sex-matched typically developing controls (n = 15) received an echocardiogram optimised for strain analysis at a single timepoint. Measures of ventricular function, mass, and size were collected. Regression modelling evaluated the impact of body mass index and intellectual and developmental disabilities diagnosis on these cardiac measures.

RESULTS

In regression modelling, an elevated body mass index z-score was associated with diminished systolic biventricular function by global strain (left ventricular longitudinal strain β 0.87, P < 0.001; left ventricular circumferential strain β 0.57, p 0.003; right ventricular longitudinal strain β 0.63, P < 0.001). Diminished left ventricular diastolic function by early diastolic strain rate was also associated with elevated body mass index (global longitudinal end-diastolic strain rate β -0.7, P < 0.001). No association was found between traditional (non-strain) measures of systolic and diastolic ventricular function and body mass index z-score.

CONCLUSIONS

Obesity in adolescents with Down syndrome or autism negatively impacts cardiac function as measured by echocardiographic strain analysis that was not detected by traditional parameters.

The influence of somatic maturity on the relationship between the triglyceride/high-density lipoprotein ratio and vascular health in children and adolescents with dyslipidemia

INTRODUCTION

Both the triglyceride to HDL cholesterol (TG/HDL) ratio and timing of pubertal maturation have been identified as independent contributors to the development of atherosclerosis.

OBJECTIVE

The purpose of our study was to determine the relationship between the TG/HDL ratio and measures of vascular health in children and adolescents with dyslipidemia stratified by somatic maturity. We hypothesized that somatic maturity would have a significant interaction with TG/HDL ratio and vascular health.

METHODS

This was a longitudinal analysis of 120 children and adolescents (age 8-14 years) with dyslipidemia recruited from a pediatric preventive cardiology clinic. At baseline and each follow-up visit, a non-fasting serum lipid panel was collected and vascular health (carotid artery intima--media thickness, pulse wave velocity, augmentation index) was assessed. Peak height velocity (PHV) was calculated at each visit, and participants were stratified into groups by maturity offset (pre-PHV, mid-PHV, post-PHV). A mixed model design permitted baseline and follow-up visits to be classified as discrete data points.

RESULTS

Of the n = 235 data points (pre-PHV = 23%, mid-PHV = 19%, and post-PHV = 58%), we identified no significant interaction between TG/HDL ratio, maturity offset, and measures of vascular structure or function. There was also no significant relationship found between TG/HDL and maturity group. Within the mid-pubertal group, there was weak relationship found between TG/HDL and augmentation index.

CONCLUSION

Despite the well-described relationship between early pubertal maturation and development of cardiovascular risk factors in adulthood, we found that vascular damage resulting from an elevated TG/HDL ratio is not independently associated with somatic maturity.

P1548 Changes in left ventricular deformation with weight loss in obese adolescents with intellectual and developmental delays (IDD)

Funding Acknowledgements

AHA Career Development grant

Background

Adolescents with IDD have twice the prevalence of obesity as their typically developed peers, leading to frequent early obesity-related subclinical cardiac dysfunction, detected by strain echo. The effects of weight loss on cardiac deformation are unknown in this population.

Purpose

To evaluate early cardiac dysfunction in overweight IDD adolescents before and after a 6-month caloric restriction-weight loss program.

Methods

Subjects with IDD co-enrolling in a weight loss program were consented for this strain imaging study, excluding those with congenital heart disease. An echo measuring LVEF (bullet), 2D speckle longitudinal LV global strain (GLS) and strain rate (GLSr) from 3 apical views and global circumferential strain from a parasternal short axis view at the paps (GCS) was performed at baseline and 6 months. Analysis included paired T-test and regression analysis, p ≤ 0.05 significant.

Results

Overweight (5) and obese (15) adolescents (40% female) had baseline LV strain measurements that were mildly diminished with increased baseline body weight predicting diminished GLS (P = 0.034) and GCS (P = 0.046) on regression modeling. After 6 months, weight and BMI decreased significantly with improvements in GLS and GCS and non-significant trends towards improvement in GLSr and early diastolic global strain rate. BMI change at 6 months predicted change in GLS (p = 0.015) and GCS (p = 0.0087) on regression modeling. At baseline, LVEF and LV end-diastolic volume were normal with no change over 6 months (p &gt; 0.55).

Conclusions

Baseline abnormalities in LV deformation with preserved LVEF are present in this young, obese IDD population with improvements in BMI predicting those in GLS and GCS after a 6-month caloric restriction-weight loss program. These data provide compelling justification for larger studies in this population.

n Baseline (mean ± SD) 6-mo. follow up 0-6 mo. change p-value Age (years) 20 17.0 ± 2.0 17.5 ± 2.1 0.5 ± 0.1 Weight (kg) 20 86.9 ± 22.2 83.1 ± 22.7 -3.7 ± 5.9 0.014 BMI (kg/m&sup2;) 20 32.2 ± 5.3 30.4 ± 5.7 -1.8 ± 2.2 0.0031 GLS (%) 20 16.9 ± 1.6 19.2 ± 2.7 2.4 ± 2.0 0.00023 GLSr 20 1.15 ± 0.018 1.22 ± 0.18 0.06 ± 0.16 0.096 EaGLSr 20 1.83 ± 0.038 2.01 ± 0.46 0.18 ± 0.45 0.098 GCS (%) 20 19.1 ± 2.3 22.0 ± 2.6 2.82 ± 2.6 0.00019 LV deformation before and after weight loss. GLS, GLSr, and GCS are reported as positive values (absolute values). Body Mass Index (BMI); Early Diastolic Global Longitudinal Strain Rate (EaGLSr)