Chronic
growth hormone (GH)/
insulin-like growth factor I (
IGF-I) excess is associated with considerable mortality in
acromegaly, but no data are available in
pituitary gigantism. The aim of the study was to evaluate the long-term effects of early exposure to GH and
IGF-I excess on cardiovascular and metabolic parameters in adult patients with
pituitary gigantism. Six adult male patients with newly diagnosed
gigantism due to
GH secreting pituitary adenoma were studied and compared with 6 age- and sex-matched patients with
acromegaly and 10 healthy subjects. Morphologic and functional cardiac parameters were evaluated by Doppler echocardiography.
Glucose metabolism was assessed by evaluating
glucose tolerance and homeostasis model assessment index. Disease duration was significantly longer (P<.05) in patients with
gigantism than in patients with
acromegaly, whereas GH and
IGF-I concentrations were comparable. Left ventricular mass was increased both in patients with
gigantism and in patients with
acromegaly, as compared with controls.
Left ventricular hypertrophy was detected in 2 of 6 of both patients with
gigantism and patients with
acromegaly, and isolated intraventricular septum thickening in 1 patient with
gigantism. Inadequate diastolic filling (ratio between early and late transmitral flow velocity<1) was detected in 2 of 6 patients with
gigantism and 1 of 6 patients with
acromegaly. Impaired
glucose metabolism occurrence was higher in patients with
acromegaly (66%) compared with patients with
gigantism (16%). Concentrations of
IGF-I were significantly (P<.05) higher in patients with
gigantism who have cardiac abnormalities than in those without cardiac abnormalities. In conclusion, our data suggest that GH/
IGF-I excess in young adult patients is associated with morphologic and functional cardiac abnormalities that are similar in patients with
gigantism and in patients with
acromegaly, whereas occurrence of impaired
glucose metabolism appears to be higher in patients with
acromegaly, although patients with
gigantism are exposed to GH excess for a longer period.