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.