Coronary flow reserve is impaired in patients with adult growth hormone (GH) deficiency

Abstract

Objective: Relationship between adult growth hormone deficiency (AGHD) and increased cardiovascular disease risk is very well known in hypopituitary patients treated with conventional hormone replacement therapy other than growth hormone (GH) administration. Endothelial dysfunction, an early and reversible event in pathogenesis of atherosclerosis, is associated with increased vascular smooth muscle tone, arterial stiffening and intima-media thickness (IMT). Coronary flow reserve (CFR) measurement by transthoracic Doppler echocardiography (TTDE) reflects coronary microvascular and endothelial functions, as a cheaper and an easy screening test. We have used TTDE to evaluate endothelial function and coronary microvascular function in AGHD.

Design: Cross-sectional observational study.

Patients: A total of 10 GH-deficient adults on conventional replacement therapy other than GH (4 males, 6 females; mean age 37 +/- 11 years) and 15 healthy subjects (7 males, 8 females; mean age 41 +/- 11 years) were studied. Patients and controls were all nonsmokers, normotensive and nondiabetic.

Measurements: IGF-1, free T4, lipid profile, insulin, glucose, insulin resistance (IR), anthropometrical and physical parameters were recorded. CFR recordings and IMT measurements were performed using the Vivid 7 echocardiography device.

Results: IMT were significantly higher in patients than controls (0.70 + 0.19 mm and 0.53 + 0.13 mm, respectively; P = 0.02). CFR was significantly lower in patients than in controls (1.96 +/- 0.35 and 2.62 +/- 0.45, respectively; P < 0.001). CFR was positively correlated with IGF-1 levels (r = 0.54, P = 0.005).

Conclusion: CFR is significantly lower in adults with GH deficiency than in controls. Direct correlation between CFR and IGF-1 concentrations suggests GH replacement could improve microvascular function and thereby could decrease cardiovascular morbidity and mortality in AGHD.