Selective venous sampling for ACTH in Cushing's disease

Abstract

Selective catheterization was carried out in fifteen patients with Cushing's disease and one patient with Cushing's syndrome, and venous samples were obtained for the measurement of adrenocorticotropic hormone (ACTH). Transsphenoidal microsurgery revealed pituitary adenomas in fifteen patients. In nine of the fifteen patients, ACTH levels in the inferior petrosal sinus or jugular vein were unequivocally higher than the simultaneous peripheral value. The ratios were greater than 2.0 with a range of 2.2 to 9.5. The ratios in the superior vena cava and inferior vena cava were smaller than 2.0 except in one case. When the peripheral mean ACTH values were raised, the ratios in the jugular vein tended to be greater. In five patients with pituitary microadenoma bilateral inferior petrosal sinuses or jugular veins were successfully catheterized, and in four of them the results of selective venous sampling were correlated with the laterality of pituitary microadenoma. In one patient without pituitary adenoma, the peripheral mean ACTH value was very high, and the ratios in the inferior petrosal sinus and jugular vein were smaller than 2.0. Selective venous ACTH sampling from the inferior petrosal sinus or jugular vein is a useful aid for the differential diagnosis of Cushing's syndrome, when standard clinical and biochemical studies are inconclusive, and in diagnosing the localization of pituitary adenoma.