ESPN 50th Annual Meeting

ESPN 2017


 
Elevated Time-varying Myocardial Wall Stress in Children with hypertension
HAOTIAN GU 1 PHIL CHOWIENCZYK 1 JOHN SIMPSON 2 MANISH SINHA 2

1- KINGS COLLEGE LONDON
2- EVELINA LONDON CHILDRENS HOPSITAL
 
Introduction:

Myocardial wall stress (MWS) has been shown in adults with hypertension to be a primary determinant of ventricular remodeling, the changes in left ventricular (LV) geometry and structure. Studies investigating time-varying arterial load and instantaneous LV geometry as determinants of wall stress in children with hypertension have not been performed.

Material and methods:

Transthoracic echocardiographic imaging of the left ventricle was performed and endocardial and epicardial volumes obtained from Tomtec wall tracking analysis. Carotid tonometry during systole was used to estimate LV pressure and was calibrated by mean and diastolic blood pressure (BP). MWS was calculated from LV volume and pressure measurements. Eighty children (41 boys) aged 13.0 ± 3.0 (mean ± SD) years (29 normotension and 51 hypertension) were studied.

Results:

Children with hypertension were older (Hypertension VS normotensive: 14.1±2.8 VS 11.0±3.3 years, p<0.001) and have higher body mass index (BMI) (22.3±4.6 VS 19.4±4.3 kg/m2, p=0.007), systolic (132±19 VS 103±11mmHg, p<0.001) and diastolic BP (72±16 VS 57±11mmHg, p<0.001) than controls. LVM (120.0±37 VS 79.0±29.5g, p<0.001), LVM index (33.6±9.6 VS 28.1±5.1 g/m2.7, p=0.006) and relative wall thickness (RWT) (0.39±0.07 VS 0.32±0.05, p<0.001) were higher in children with hypertension than in those with normotension.  Peak stress (Normotensive VS Hypertension: 338.8±18.5 VS 397.5±14.3 kdyne/cm2, p<0.001) and mean stress (323.6±14.5 VS 411.7±13.8 kdyne/cm2, p<0.001) was significantly elevated following adjustment for age, BMI and LVM index    This relation disappeared after adjustment for blood pressure indices.

Conclusions:

In children with hypertension, despite evidence of LV geometry alteration, MWS remained elevated and was explained by high blood pressure alone. We would postulate that improved blood pressure control may improve LV remodeling.