The effect of recombinant human growth hormone therapy on left-ventricular chamber size and function in children with growth hormone deficiency

Evaluation of cardiac structure, exercise capacity and electrocardiography parameters in children with partial and complete growth hormone deficiency and their changes with short term growth hormone replacement therapy

PURPOSE

To evaluate cardiac structure, exercise capacity and electrocardiography (ECG) parameters of children with complete and partial growth hormone (GH) deficiency (GHD) and the effect of 12 months GH treatment on these.

METHODS

M-mode echocardiography, ECG and exercise test expressed as metabolic equivalent (MET) were performed in children with GHD, aged 9-14 years, divided into those with a peak GH response < 7 µg/L (complete GHD; n = 30) and 7-10 µg/L (partial GHD; n = 17) after two GH stimulation tests, at baseline and 12 months after GH initiation. Forty-eight healthy peers underwent the same tests once.

RESULTS

Left ventricular mass (LVM) was significantly lower before treatment in both groups with GHD compared to healthy peers (p = 0.015 and p = 0.032) but LVM in the GHD groups was similar to controls after 12 months of treatment. The increase in LVM in the complete GHD group was significant (p = 0.044). LVM index was significantly reduced with treatment in children with partial GHD (p = 0.035). Max METs, VO_2max and exercise duration were significantly increased in children with complete GHD after treatment (p = 0.022, p = 0.015 and p = 0.002, respectively). Significant changes in P wave and QTc dispersion on ECG between groups were within physiological limits.

CONCLUSION

This study showed that children with both partial and complete GHD had smaller cardiac structures and less exercise capacity compared to their healthy peers prior to GH treatment but this improved with 12 months of treatment. The cardiac trophic effect of GH, as well as the effect of increasing exercise capacity, is greater in those with complete GHD than in those with partial GHD.

Cardiac functions in children with growth hormone deficiency: Effects of one year of GH replacement therapy

INTRODUCTION

Children with Growth Hormone deficiency (GHD) are prone to heart dysfunction and, if left untreated, will result in marked cardiac dysfunction in adulthood. The aim was to evaluate the effect of GHD and growth hormone (GH) therapy on cardiac structure in children and adolescents, and to investigate the role of insulin like growth factor-1 (IGF-1) in this.

METHODS

M-mode, pulse-wave Doppler echocardiography and tissue Doppler imaging (TDI) were performed in 49 children with GHD who were divided into those with a peak GH response < 7 μg/L and 7-10 μg/L after two GH stimulation tests, aged 8-16 years at baseline and at six and 12 months after GH initiation, and 49 healthy peers. IGF-1 concentration was measured.

RESULTS

Although the left ventricular end diastolic and systolic diameters in both GH deficient groups were significantly lower than controls (p < 0.01), both diameters increased significantly with one year of treatment and achieved normal values (p > 0.05). Using TDI in both two patients group revealed increased E/A, prolonged isovolumic relaxation time, shortened ejection time, and a significant increase in myocardial performance index compared to controls (p < 0.001). Significant improvement was observed in these parameters from the sixth month of GH treatment (p < 0.001), this improvement does not match parameters measured in healthy peers, even after one year of treatment in both patients group. (p < 0.001). No correlation was found between IGF-1 concentration and any echocardiographic parameter.

CONCLUSION

Echocardiographic parameters were similar in children with a GH peak < 7 μg/L and 7-10 μg/L. In TDI, both systolic and diastolic function was impaired in GHD children compared to controls. These parameters improved after one year of GH therapy but did not recover to healthy control levels.

Cardiovascular Risk in Growth Hormone Deficiency: Beneficial Effects of Growth Hormone Replacement Therapy

Growth hormone deficiency (GHD) in adulthood is associated with an increased risk of developing adverse cardiovascular events and with reduced life expectancy. Cardiovascular and metabolic abnormalities have so far been evaluated only in a small number of children with GHD and adolescents. In this article we review these abnormalities and their underlying mechanisms and discuss the beneficial effect of growth hormone treatment in subjects with GHD.