Impact of successful transsphenoidal surgery on cardiovascular risk factors in acromegaly

Background: Cardiac abnormalities develop in patients with acromegaly as a consequence of effects of GH/IGF-I on the heart and related cardiovascular risk factors. Objective: To evaluate the possible contribution of postoperative variations in blood pressure (BP), glucose tolerance and insulin sensitivity to the cardiac improvement reported in patients who have been cured of acromegaly. Design: Thirty-one patients with acromegaly were studied before and 6 months after successful transsphenoidal surgery, defined by normal age-related IGF-I concentrations and glucose-suppressed GH concentrations <1 μg/l. Methods: Cardiovascular parameters were assessed by Doppler echocardiography and 24-h ambulatory blood pressure monitoring. Insulin sensitivity indexes were calculated on the basis of fasting and post-load glycaemia and insulinaemia and referred to as HOMAISI and OGTTISI, respectively. Results: Successful surgery was confirmed to improve left ventricular mass index (LVMI) and diastolic filling significantly. Mean 24-h systolic BP values decreased (P = 0.009) and BP rhythm was restored in 12 of 15 patients with a blunted preoperative profile. Glucose tolerance normalized in patients with preoperative glucose intolerance (n = 7) or diabetes mellitus (n = 3). HOMAISI and OGTTISI increased (P = 0.0001 for each parameter), indicating a marked improvement in insulin sensitivity. The post-operative reduction in LVMI correlated with increased insulin sensitivity (P < 0.001 for both indexes), but not with other parameters. Improved diastolic filling correlated with the reduction in LVMI. Conclusions: Successful surgery in patients with acromegaly induces a significant improvement in haemodynamic and metabolic risk factors. This study suggests a direct link between insulin resistance and acromegalic cardiomyopathy.