Treatment with growth hormone receptor antagonist in acromegaly: effect on cardiac structure and performance

The aim of the current study was to evaluate the effect of short-term (6 months) and long-term (18 months) treatment with pegvisomant on cardiac structure and performance in patients with acromegaly.

Seventeen patients (nine women, eight men, 27-61 yr) with active acromegaly entered and 12 completed the long-term study. After a baseline evaluation, including measurement of hemodynamic, biochemical, and hormonal parameters, and a standard Doppler echocardiography, treatment with pegvisomant was started at the initial dose of 10 mg/d, increasing by 5 mg/d every 6 wk on the basis of IGF-I levels until normalization or the achievement of a maximal dose of 40 mg/d.

After short-term treatment, IGF-I levels were normalized in 10 of the 17 (59%) patients. Left ventricular mass index (LVMi) was significantly decreased without changes in diastolic and systolic performance. After long-term treatment, IGF-I levels were normalized in 10 of the 12 (83%) patients. Blood glucose and serum insulin levels were decreased compared with baseline. LVMi was further decreased compared with short-term treatment, so that the prevalence of left ventricle hypertrophy decreased from 50% at baseline to 17% after 18 months of treatment. Moreover, ejection fraction as well as early to late (atrial) peak velocity ratio (E/A) were significantly increased, whereas isovolumic relaxation time was significantly decreased compared with baseline, demonstrating an improvement of both diastolic and systolic function. A significant correlation was found between the change in IGF-I levels and that of left ventricular ejection fraction. In general, the prevalence of cardiac insufficiency was present in 13 of the 17 (76%) patients at baseline and in one (8%) patient after 18 months of treatment.

Long-term treatment with the GH receptor antagonist improves acromegalic cardiomyopathy by decreasing cardiac hypertrophy and enhancing diastolic and systolic function, and consequently partially or completely reverting the cardiac insufficiency.