Cardiac Mass and Function, Carotid Artery Intima-Media Thickness, and Lipoprotein Levels in Growth Hormone-Deficient Adolescents

Abstract

The objective of our study was to evaluate whether cardiac mass and function, carotid artery intima-media thickness, and serum lipid and lipoprotein(a) levels are abnormal in adolescents with GH deficiency. Young adults with childhood-onset and adulthood-onset GH deficiency have been found to have a higher cardiovascular risk, as manifested among other factors by reduced left ventricular mass, impaired systolic function, significant increase in arterial intima-media thickness, and dyslipidemia. Twelve adolescents (seven males and five females) with GH deficiency (10 idiopathic and 2 organic), with an age of 14.2 ± 2.8 yr and a height of 140.6 ± 17.9 cm (height sd score,− 2.6 ± 0.3), were studied. Six children had received GH in the past but were off therapy for several years, whereas six patients had never been treated with GH. Fasting blood samples were obtained for serum lipids and lipoprotein(a) analysis. Patients underwent transthoracic M-mode and two-dimensional echocardiographic evaluation for measurement of interventricular septal thickness, left ventricular posterior wall thickness, and left ventricular mass, as well as left ventricular ejection fraction at rest and pulmonary venous flow velocities; carotid artery intima-media thickness was measured using high-resolution mode B ultrasound. Seven GH-deficient (GHD) adolescents on GH at the time of the study and 19 healthy adolescents, all comparable for age, pubertal status, height, weight, blood pressure, and pulse, participated in this study as controls. Interventricular septal thickness (6.5 ± 1.3 vs. 7.0 ± 1.5 mm), left ventricular posterior wall thickness (7.0 ± 1.8 vs. 7.5 ± 2.0 mm), and left ventricular mass after correction for body surface area (71.2 ± 21.8 vs. 70.7 ± 18.0 g/m2) were similar in untreated GHD patients and healthy controls. Similarly, the left ventricular ejection fraction at rest was similar in untreated GHD subjects and controls (70.0 ± 0.7 vs. 70.0 ± 0.6%), as were the pulmonary venous flow velocities (0.54 ± 0.16 vs. 0.55 ± 0.10 m/s for diastolic peak velocity; 0.51 ± 0.16 vs. 0.50 ± 0.09 m/s for systolic peak velocity; and 0.19 ± 0.06 vs. 0.19 ± 0.05 m/s for atrial reversal filling). Carotid artery intima-media thickness (0.60 ± 0.02 mm and 0.59 ± 0.02 mm for the right and left carotid arteries, respectively) was also normal in our untreated GHD patients when compared with healthy controls. In addition, all echocardiographic measurements were similar in GHD subjects on or off GH at the time of the study. Low-density lipoprotein cholesterol levels were increased in untreated GHD patients when compared with healthy controls (3.17 ± 0.70 vs. 2.33 ± 0.36 mmol/L; P < 0.01), whereas total cholesterol, high-density lipoprotein cholesterol, and triglyceride concentrations were similar to that of controls. Total cholesterol levels were increased in our untreated GHD adolescents when compared with GHD subjects receiving GH therapy at the time of the study, while low-density lipoprotein cholesterol and triglyceride levels were also elevated, although not significantly. Lipoprotein(a) levels were elevated in untreated GHD adolescents when compared with healthy controls, and untreated GHD subjects had higher lipoprotein(a) concentrations than GH-treated patients. GHD adolescents, regardless of whether or not they received GH therapy, do not seem to show alterations in cardiac mass and function or early atherosclerotic changes. They must, however, be followed carefully because they already present cardiovascular risk factors such as dyslipidemia, which may increase their cardiovascular morbidity over time.