Selective venous sampling in diagnosing ACTH dependent hypercortisolism

PURPOSE: To evaluate the sensitivity of selective sampling from the inferior petrosal sinuses in the differential diagnosis of ACTH-dependent hypercortisolism with non-diagnostic pituitary imaging. MATERIALS AND METHODS: Between 1987 and 2001, 17 patients (14 women and 3 men, aged 18-63 years) with ACTH-dependent hypercortisolism and negative X-ray of the sellar region, underwent simultaneous bilateral sampling from the inferior petrosal sinuses with ACTH measurement, at baseline and after stimulation with CRH (100 micro i.v.). Baseline samplings were also carried out at the level of the infrarenal and suprarenal inferior vena cava, of the adrenal and suprahepatic veins, of the superior vena cava, of the jugular veins, and of a peripheral vein. A central/peripheral gradient >2 at baseline and/or one >3 after stimulation with CRH was considered indicative of the pituitary origin of ACTH. Bilateral femoral venous catheterization was performed in an angiographic room using 5-French introducers after local anaesthesia. Selective catheterization of the inferior petrosal sinuses was achieved with 100 cm-long, steam-bent (45 degrees) 5-French catheters, without lateral holes. RESULTS: Twelve patients exhibited ACTH central/ peripheral gradients indicating the pituitary origin of the hormonal hyperincretion; this was confirmed by surgical exploration of the hypophysis in 10 patients, whereas 2 refused surgery and were therefore "lost". Of the five patients without ACTH central/peripheral gradients, one had an adrenal metastasis from ACTH-secreting lung neoplasia (with ACTH gradient in the blood flowing back from the adrenal gland), one had a hepatic CRHoma (with high levels of CRH in the suprahepatic veins), whereas the origin of the hyperincretion remained indeterminate in three. CONCLUSIONS: Bilateral simultaneous selective sampling from the inferior petrosal sinuses for ACTH measurements proved to be highly sensitive and free of complications in the differential diagnosis of ACTH-dependent forms of hypercortisolism.