Figure 1.

AVS protocol with simultaneous and triplicate sampling. AVS began with cannulation of the femoral veins and measurement of the unstimulated aldosterone and cortisol in the IVC (t = −15 minutes). Two catheters were then threaded into the bilateral adrenal veins and confirmed using adrenal venography and adjunctive cone-beam computed tomography, in a process that typically took 15 minutes. Once the bilateral adrenal venous catheters were in place, measurements of unstimulated aldosterone and cortisol were obtained simultaneously from the bilateral adrenal veins every 5 minutes for a total of 3 samples each. With the adrenal vein catheters still in place, a single intravenous injection of 250 mcg of ACTH was then administered and simultaneous measurements of stimulated aldosterone and cortisol were obtained 5, 10, and 15 minutes after the ACTH injection. Once the final stimulated samples were obtained from each adrenal vein, the catheters were withdrawn and a final stimulated sample of aldosterone and cortisol was obtained from the IVC. Abbreviation: AVS, adrenal venous sampling.