Endocrine Abstracts

Introduction: Acromegaly is a rare chronic disorder caused by growth hormone hypersecretion due to GH-producing pituitary adenoma. Surgery is the first-line treatment modality. However, patients with severe cardiac involvement are high-risk candidates for pituitary surgery. These patients may benefit from rapid preoperative biochemical control of acromegaly. There is emerging evidence of efficacy of pegvisomant, a GH-receptor antagonist, (either alone or in combination with somatostatin receptor ligands) in achieving rapid normalization of IGF-1. However clinical experience in using pegvisomant as monotherapy in preoperative setting in high-risk cardiac patients is lacking.

We present two cases with acromegaly-induced dilated cardiomyopathy (DCM) who had preoperative treatment with pegvisomant.

Case reports: Case 1: A 53-year-old woman with biochemically confirmed acromegaly (random GH 10.5 mg/l (normal range 0.02–1.23), IGF1 1015 mg/l (normal range 71–224)) was referred to our clinic. Neuroimaging (MRI) of the head revealed a pituitary adenoma (15 × 14 × 6 mm). The patient was considered high-risk for surgery due to acromegaly-induced comorbidities especially the heart failure with reduced left ventricular ejection fracture (LVEF) of 29% and a severe mitral insufficiency. In addition, she had diabetes and obstructive sleep apnea. We started treatment with pegvisomant (daly 10 mg). Within two months of treatment, the IGF-1 decreased to 450 mg/l. LVEF improved to 37%. Not surprisingly, diabetes control also got better with reduced requirement for insulin. Tongue size and upper airway swelling decreased as well. Resection of pituitary adenoma was uneventful with complete biochemical and structural remission. Case 2: A 46-year-old man was admitted with congestive heart failure. Imaging (TTE, cardiac MRI) revealed a DCM with a LVEF of 20% and a severe aortic regurgitation. Careful clinical examination revealed typical clinical findings suggestive of acromegaly. The diagnosis was confirmed by elevated random GH; 38 mg/l and elevated IGF-1; 1080 mg/l. MRI scan of the brain showed a pituitary adenoma with infiltration of the cavernous sinus (32 × 22 × 20 mm). To optimize cardiac function, aortic valve replacement was scheduled before pituitary surgery. In addition, we started preoperative treatment with pegvisomant. After two months, the IGF-1 decreased to 700 mg/l. The aortic valve replacement was successful. LVEF in this case remained unchanged in short-term follow-up. However, NT-proBNP was regredient. The pituitary surgery is still pending.

Discussion: Severe cardiovascular disease in patients with acromegaly portends high mortality rate (almost 100% within 15 years). Preoperative treatment with pegvisomant may reduce perioperative risk by rapidly normalizing IGF-1 levels.