RAPID REDUCTION OF LEFT-VENTRICULAR HYPERTROPHY IN ACROMEGALY AFTER SUPPRESSION OF GROWTH-HORMONE HYPERSECRETION

Objective: To examine the possible role of growth hormone as a pathogenetic factor in the development of myocardial hypertrophy in acromegaly. Design: An uncontrolled clinical trial. Setting: Tertiary-care medical center. Patients: Sixteen patients with acromegaly were stratified into two groups: Group I (n = 10) had left ventricular hypertrophy (LVH), and group II (n = 6) did not have LVH. Intervention: Therapy with octreotide acetate (SMS 201-995), a long-acting somatostatin analog (mean dose, 538 mug/d), was administered for 2 months. Measurements: Plasma growth hormone and insulin-like growth factor I (IGF-I) concentrations, hand volume, and echocardiographic left ventricular dimensions and mass were measured at baseline and at 1 week and 2 months after the start of therapy. Results: Before octreotide therapy, both groups had similar hand volumes and similar growth hormone and IGF-I hypersecretion. Both groups showed a reduction in growth hormone at 2 months (mean reduction, 13.7 mug/L in patients with LVH [P < 0.01 ] and 14.1 mug/L in patients without LVH [P < 0.05]). Plasma IGF-I was also decreased (mean reduction, 305 mug/L in patients with LVH [P < 0.01] and 304 mug/L in patients without LVH [P < 0.05]). Reduction of growth hormone and IGF-I hypersecretion in patients with LVH was associated with a rapid decrease in left ventricular mass (339 g to 299 g, P < 0.01) within 1 week, which was sustained at 2 months (274 g, P < 0.04). Patients without LVH showed no statistical change in left ventricular mass. In patients with LVH, the decrease in left ventricular mass correlated with the octreotide-induced decrease in growth hormone (r = 0.79, P < 0.05) but not with blood pressure. Blood pressure, left ventricular dimensions, and percent of fractional shortening were not altered by therapy in either group. Hand volume decreased in both groups. Conclusions: Normalization of growth hormone secretion is associated with reduction of left ventricular mass in acromegalic patients with LVH within 1 week of initiating therapy with octreotide.