Conditional cardiovascular response to growth hormone therapy in adult patients with Prader-Willi syndrome

Context: In Prader-Willi syndrome (PWS), an altered GH secretion has been related to reduced cardiac mass and systolic function when compared with controls. Objectives: The objective of the study was to evaluate the cardiovascular response to GH therapy in adult PWS patients. Study Participants: Thirteen obese PWS adults (seven males and six females, aged 26.9 ± 1.2 yr, body mass index 46.3 ± 1.6 kg/m²) participated in the study. Methods: Determination of IGF-I, metabolic parameters, echocardiography, and cardioscintigraphy with dobutamine stimulation was made during 12 months GH therapy, with results analyzed by repeated-measures ANOVA. Results: GH therapy increased IGF-I (P < 0.0001); decreased C-reactive protein levels (P < 0.05); and improved lean mass (P < 0.001), fat mass (P < 0.05), and visceral fat (P < 0.001). Echocardiography showed that 6- and 12-month GH therapy increased left ventricle mass in 76 and in 61% of patients, respectively (P < 0.05), did not change diastolic function, and slightly decreased the left ventricle ejection fraction (LVEF) (P < 0.054). Cardioscintigraphy documented stable values of LVEF throughout the study, whereas right ventricle ejection fraction decreased significantly (P < 0.05) being normally responsive to dobutamine infusion. A positive association between IGF-I z-scores and LVEF occurred at the 6- and 12-month follow-up (P < 0.05). Conclusions: In PWS, GH therapy increased cardiac mass devoid of diastolic consequences. The observation of a slight deterioration of right heart function as well as the association between IGF-I and left ventricular function during GH therapy suggest the need for appropriate cardiac and hormonal monitoring in the therapeutic strategy for Prader-Willi syndrome.