Desmopressin is a safe and effective secretagogue to replace corticotropin-releasing hormone in petrosal sinus sampling

Purpose: Bilateral inferior petrosal sinus sampling (BIPSS) with corticotropin-releasing hormone (CRH) was the gold standard for distinguishing Cushing disease (CD) from ectopic ACTH secretion (EAS). CRH, however, is no longer available.

Objective: To assess the reliability of BIPSS with desmopressin to differentiate CD from EAS.

Methods: A retrospective study included patients who underwent BIPSS with desmopressin for ACTH-dependent hypercortisolism, with the whole diagnostic procedure in a single center.

Results: Fifty-eight patients with confirmed etiological diagnosis were included: 51 CD, 7 EAS. Forty-three CD patients (84.3%) had post-stimulation ratio ≥2 before stimulation and 6 of the other 8 (75%) had a ratio ≥3. All EAS patients were correctly diagnosed before and after stimulation. Sensitivity was 84.3% before stimulation and 92.2% combining pre- and post-stimulation results; specificity reached 100%. A ROC curve established optimal thresholds at 1.4 before stimulation and 1.7 after.

Conclusion: Desmopressin is a good substitute for CRH, correcting diagnosis compared to baseline BIPSS in 12% of cases.