M-mode echocardiographic evaluation of systolic function, LV volume and mass in children on growth hormone therapy

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.

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

This study was designed to assess the effect of recombinant human growth hormone (rhGH) therapy on left-ventricular (LV) chamber size and function in children with idiopathic isolated growth hormone deficiency (GHD) using conventional echocardiography and tissue Doppler imaging (TDI). Thirty patients (19 boys and 11 girls) with idiopathic isolated GHD were followed-up for 12 months. Mean age of patients was 11.0 ± 2.6 years (range 6.3-15.5). At baseline and at 3, 6, and 12 months of treatment, the structure of the left ventricle was assessed by conventional echocardiography and myocardial rates and time intervals by TDI. There was a significant increase in LV mass (LVM) compared with pretreatment values. Like LVM, relative wall thickness (RWT) was also increased significantly. The significant increase in LVM indexed to body surface area and RWT became apparent at month 3 of treatment with a significant increase in LVM indexed to height(2.7) at treatment month 6. Normalized LVM increased as early month 3 of treatment, and a steady increase was observed until month 12. However, no patient had LVM > +2 standard deviation scores at month 12 of treatment. No significant differences were observed in functional parameters of the left ventricle and the interventricular septum. The results of this study showed that rhGH therapy causes an increase in myocardial mass without changing the geometry or function of the myocardium. Therefore, the increase in myocardial mass appears to be concentric, thus causing remodeling instead of hypertrophy.

Growth hormone: health considerations beyond height gain

The therapeutic benefit of growth hormone (GH) therapy in improving height in short children is widely recognized; however, GH therapy is associated with other metabolic actions that may be of benefit in these children. Beneficial effects of GH on body composition have been documented in several different patient populations as well as improvements in lipid profile. Marked augmentation of bone mineral density also seems evident in many pediatric populations. Some of these benefits may require continued therapy past the acquisition of adult height. With long-term therapy of any kind, the adverse consequences of treatment should also be considered. Fortunately, long-term GH treatment seems to be safe and well-tolerated. This review describes the long-term metabolic effects of GH treatment in the pediatric population and considers how these may benefit children who are treated with GH.

Effects of growth hormone on anthropometric measurements and cardiac function in children with thermal injury

Severe burn injuries are associated with growth delays a persistent hypermetabolic response and severe muscle catabolism and wasting. Growth hormone (GH), a potent anabolic agent and salutary modulator of post-traumatic metabolic responses has been shown to decrease muscle wasting, improve net protein synthesis and attenuate growth delays in burned children. In non-burned populations, GH has recently been shown to be of benefit in enhancing cardiac performance and improving cardiac contractility and efficiency. Yet, whether administration of GH will induce similar improvements in cardiac function in severely burned children is presently unknown. We therefore, investigated whether the administration of GH initiated upon hospital discharge (95% healed) and continued for 1-year post-burn would improve resting cardiac function in burned children. Severely burned children were randomized to receive either saline placebo (n = 37) or 0.05 mg/kg per day of GH (n = 39) from discharge until 12-month post-burn. Outcome variables included height, weight, lean body mass, resting energy expenditure, cardiac index, stroke-volume index, heart rate and left ventricular ejection fraction.

RESULTS

height, weight, lean body mass and ejection fraction showed a significant increase with GH. Our results indicate that severely burned children treated with long-term GH show a significant improvement in left ventricular ejection fraction.

Left ventricular mass and function in children with GH deficiency before and during 12 months GH replacement therapy

OBJECTIVE

This open, prospective study was designed to evaluate the effect of GH deficiency (GHD) on left ventricular (LV) mass (LVM) and performance, by echocardiography, and on lipid profile during childhood.

SUBJECTS

Twelve prepubertal children with GHD (eight boys and four girls) aged 8.1 +/- 1.7 years were studied before and after 6 and 12 months of GH replacement therapy at a dose of GH of 30 micro g/kg/day. Twelve healthy children sex-, height-, weight- and body surface area-matched with the patients, served as controls.

METHODS

Echocardiography was performed at study entry and after 12 months both in GHD children and in controls. Only in GHD children, echocardiography was repeated also after 6 months of GH replacement. In all subjects, we measured LV posterior wall thickness (LVPWT), LV end-diastolic diameter (LVEDD), LVM index (LVMi), LV systolic and diastolic function.

RESULTS

At study entry, LVPWT (5.3 +/- 0.8 vs. 6.2 +/- 1.1 mm, P < 0.05), LVEDD (34.0 +/- 2.4 vs. 36.7 +/- 2.1 mm, P < 0.007) and LVMi (47.0 +/- 6.9 vs. 59.6 +/- 9.5 g/m2, P < 0.005) were significantly lower in GHD children than in controls. Lipid profile, heart rate, blood pressure, LV systolic function and indices of ventricular filling were similar in patients and controls. After 12 months of GH replacement therapy, LVPWT (6.1 +/- 0.7 mm, P < 0.0005), LVEDD (38.8 +/- 4.3 mm, P < 0.002) and LVMi (71.5 +/- 12.7 g/m2, P < 0.0005) significantly increased in GHD children compared to pretreatment values. In particular, after 12 months of therapy GHD children achieved a normal LVMi when compared to controls (60.7 +/- 8.6, P = ns). LVMi increase was significantly correlated with the increase in IGF-I level (r = 0.49; P < 0.004). LV systolic performance, diastolic filling and blood pressure did not change significantly during GH therapy. After 12 months of treatment, the atherogenic index, measured as total/high-density lipoprotein-cholesterol ratio (2.7 +/- 0.8) was significantly lower than both pretreatment (3.4 +/- 0.3, P < 0.03) and control values (3.8 +/- 1.1, P < 0.04).

CONCLUSIONS

GH deficiency in children affects heart morphology, by inducing a significant decrease in cardiac size, but does not modify cardiac function and lipid profile. Twelve months of GH replacement treatment normalizes cardiac mass, and reduces the atherogenic index.