Multi-center comparison of corticotropin releasing hormone vs. desmopressin stimulation responses in inferior petrosal sinus sampling for Cushing's disease.

OBJECTIVES

Inferior petrosal sinus sampling (IPSS) is important for confirming Cushing's Disease (CD). Due to lack of corticotropin releasing hormone (CRH) availability, desmopressin/DDAVP is being used as the alternative stimulating agent but has limited data regarding testing cutoffs.

DESIGN

We compared the stimulation profiles of desmopressin and CRH in patients with CD.

METHODS

Data from the multi-center Registry of Adenomas of the PItuitary and Related Disorders (RAPID) was evaluated. 93 patients with CD confirmed by pathology or biochemical remission that underwent IPSS testing prior to surgical resection (desmopressin [n = 57], CRH [n = 36] or both [n = 1]). IPSS stimulation using desmopressin or CRH according to individual institutions. Central:peripheral normalized adrenocorticotropin hormone (ACTH) ratio at baseline and post-stimulation were analyzed.

RESULTS

No difference in demographic, surgical, or follow-up remission characteristics were seen between desmopressin or CRH patients. ACTH ratio increased earlier and were significantly higher after CRH stimulation at 2 min compared with desmopressin (130 ± 177.8 vs. 33.5 ± 45.0 pg/mL, p = 0.0002). ACTH ratio increased on average 6.3X after 2 min with CRH stimulation and 2.7X with either agent at 5 min. 72/93 (77%) patients showed > 2X ACTH ratio from baseline. A total of 51/57 (89%) and 33/36 (91.7%) of patients showed > 3X post-stimulation ACTH ratio with desmopressin or CRH, respectively.

CONCLUSIONS

CRH showed a more robust stimulation response than desmopressin for ACTH ratio during IPSS at 2 min but both agents showed similar effect at 5 min. Elevations of ACTH of 2.7X after desmopressin stimulation at 2-5 min may help identify sellar sources of ACTH.