Progression of cardiovascular disease in acromegalic patients treated by external pituitary irradiation.

Cardiovascular complications are a major cause of morbidity and mortality in acromegaly and seem to be related to the long duration of the disorder. Conventional external pituitary irradiation for acromegaly produces a consistent, but slow, fall in elevated serum growth hormone (GH) levels. It has not been established whether such treatment is effective in preventing the development of cardiovascular complications. The evolution of cardiovascular disease has therefore been studied in 11 acromegalic patients followed up for a mean 10 years (range 3-17) after external pituitary irradiation. At the final follow-up fasting serum GH were significantly (P less than 0.01) lower than pre-irradiation levels, but cardiovascular events (myocardial infarction, dysrhythmias, hypertension, major arterial disease, heart failure) increased significantly in prevalence (P less than 0.01) during this period. Electrocardiographic abnormalities also increased in prevalence. At the final follow-up 6 patients had cardiomegaly on chest X-ray and echocardiographs (10 patients) were abnormal in every case. All 11 patients had evidence of complete or partial anterior hypopituitarism. We confirm that external pituitary irradiation is effective in reducing elevated serum GH levels in acromegaly, but suggest that such a slow reduction in serum GH levels does not retard the development of cardiovascular complications.