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 microg/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 HOMA(ISI) and OGTT(ISI), 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). HOMA(ISI) and OGTT(ISI) increased (P=0.0001 for each parameter), indicating a marked improvement in insulin sensitivity. The postoperative 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.