Interaction between myocardial and vascular changes in obese children: a pilot study

Abstract

Background: Changes in vascular and myocardial structure and function have been demonstrated in obese children, but limited data are available on how these changes are related. The aims of this study were to investigate vascular and myocardial changes in obese children with lipid abnormalities and to study the interactions between vascular and myocardial parameters.

Methods: A cross-sectional, prospective observational study was conducted. Twenty-one obese and 27 normal-weight controls aged 14 ± 2 years participated. Cardiac assessment included geometric parameters and myocardial deformation (strain and strain rate) analysis by color tissue Doppler and speckle-tracking echocardiography. Vascular assessment included carotid intima-media thickness, flow-mediated dilatation, pulse-wave velocity, and other stiffness measures of the aorta and carotid artery, as well as noninvasive estimation of arterial elastance and left ventricular (LV) end-systolic elastance.

Results: Obese children compared with controls had lower color tissue Doppler-derived LV systolic radial strain values (45 ± 11% vs 56 ± 12%, P = .002), lower speckle-tracking echocardiography-derived LV systolic longitudinal strain values (-18 ± 2% vs -21 ± 2%, P < .001), and lower speckle-tracking echocardiography-derived LV early diastolic strain rate values (1.7 ± 0.3 vs 2.5 ± 0.4, P < .001). Carotid intima-media thickness was increased, pulse-wave velocity was faster, and arterial distension coefficients were lower in obese children. The ratio of arterial elastance to LV end-systolic elastance (a marker of ventricular-arterial coupling) was lower in obese children than controls (0.73 ± 0.32 vs 0.47 ± 0.15, P = .003). Changes in vascular parameters were correlated with changes in longitudinal myocardial deformation parameters.

Conclusions: Obese children with lipid abnormalities have reduced systolic and diastolic LV deformation characteristics, early vessel wall changes, and increased arterial stiffness. Abnormal ventricular-vascular interaction is suggested by these data and warrants further investigation.