The influence of growth hormone therapy on ultrasound myocardial tissue characterization in patients with childhood onset GH deficiency

Abstract

Background: In growth hormone deficiency (GHD), a reduction in left ventricular mass (LV-mass) and impairment of systolic function has been shown. In this study, we investigated the effects of 12 months of GH replacement therapy on cardiac structure and functional indices measured by echocardiographic techniques in adult patients with childhood onset GH deficiency. Methods: Sixteen patients (age 42.3±13.1 years, 10 males) were investigated before and after 12 months of GH treatment at a dose of 0.02 IU/kg/day (7 μg/kg/day). Echocardiography was performed including the ultrasound myocardial tissue characterization technique. We measured two parameters of the ultrasonic tissue characterization with integrated backscatter: the magnitude of the cardiac-cycle-dependent variation in integrated backscatter signals (CV-IBS) and the mean value of integrated backscatter signals calibrated by the pericardium (cal-IBS). Results: Left ventricular diameter and wall thickness did not change after GH treatment, although systolic increase in interventricular septum thickness (IVS%) and systolic increase in posterior wall thickness (PWT%) increased significantly (IVS% 52.2±31.9% vs. 67.3±30.4% and PWT% 48.7±20.2% vs. 58.0±17.7%, p<0.01 and p<0.01, respectively). Ejection fraction increased from 56.2±7.2% to 63.2±6.1% ( p<0.01). LV-mass index did not change after GH treatment (78.4±22.1 vs. 81.9±21.1 g/m 2). CV-IBS increased significantly after GH treatment ( p<0.05), in both the interventricular septum and the left ventricular posterior wall (4.7±1.5 vs. 5.8±1.9 dB for the interventricular septum, 4.9±1.8 vs. 6.5±2.4 dB for the left ventricular posterior wall, p<0.05 and p<0.05, respectively). Cal-IBS also increased significantly after GH treatment (−23.5±4.1 vs.−21.8±4.2 dB for the interventricular septum, −23.0±4.4 vs. −21.8±4.3 dB for the left ventricular posterior wall, p<0.01 and p<0.05, respectively). Conclusion: Twelve months GH treatment in adults with childhood onset GHD resulted in improvement of cardiac contractile performance. Observed changes in cal-IBS and CV-IBS suggest that GH treatment in this patient group can lead to a further somatic maturation of the heart, probably not accomplished previously.