Purpose: Acromegaly is associated with increased cardiovascular morbidity and mortality when inadequately treated, which may be secondary to associated comorbidities or to direct IGF-1 effects on the cardiovascular system. By using a control group carefully matched for traditional cardiovascular risk factors, we aimed to assess the direct contribution of disease activity and IGF-1 levels to arterial damage as assessed by measurements of arterial stiffness and endothelial function.
Methods: Twenty-nine subjects with acromegaly (11 males, 52 ± 14 year; 15 active acromegaly) and 24 matched controls underwent evaluation of large and small artery compliance using applanation tonometry, pulse wave velocity (PWV), augmentation index (Alx), carotid ultrasonography intima-media thickness, (IMT) and flow-mediated dilatation (FMD).
Results: IGF-1 expressed as times the upper limit of the normal range (x ULN) was 2.2 ± 1.1 in patients with active disease versus 0.7 ± 0.2 in patients in remission. Irrespective of disease activity, FMD was lower in patients with acromegaly than in control subjects, (3.4 ± 2.7 % in active acromegaly, 4.4 ± 3.3 % in controlled acromegaly and 7.5 ± 3.8 % in controls; p = 0.004). There were no significant differences in PWV, Alx, and IMT between groups. A positive correlation was found between IGF-1× ULN and IMT (r = 0.4; P = 0.02). Asymmetric dimethylarginine (ADMA), a novel cardiovascular risk factor, was positively correlated to arterial stiffness (r = 0.46; p = 0.017) and negatively with small vessel compliance (r = -0.44, p = 0.02).
Conclusions: Patients with acromegaly have significantly impaired endothelial function as assessed by FMD, but other tested vascular parameters were similar to a control group that was adequately matched for cardiovascular risk factors.
Keywords: ADMA; Acromegaly; Cardiovascular risk factors; Endothelial function; Vascular function.