Lateralization outcomes of bilateral inferior petrosal sinus sampling: desmopressin vs CRH

Purpose: Bilateral inferior petrosal sinus sampling (BIPSS) is the gold standard for localizing ACTH-dependent Cushing's syndrome (CS). While corticotropin-releasing hormone (CRH) was initially used for stimulation, desmopressin has become a common alternative. This research evaluates desmopressin's effectiveness in lateralizing Cushing's disease (CD) during BIPSS compared to CRH stimulation. Methods: The study included 33 individuals with ACTH-dependent CS who underwent BIPSS and had diagnoses confirmed by endoscopic endonasal transsphenoidal pituitary surgery (EETPS). Fourteen participants underwent BIPSS with CRH and 19 with desmopressin. A comparative analysis was conducted. Results: BIPSS accurately lateralized 76% of cases, specifically, 71% with CRH and 79% with desmopressin (p = 0.2). For tumors < 6 mm on MRI, overall accuracy was 82%, namely, 75% with CRH and 90% with desmopressin (p = 0.4). IPSS achieved 100% accuracy in the four cases with no lesion on preoperative MRI. Conclusion: This study demonstrates no significant difference in lateralization accuracy between desmopressin and CRH for IPSS. In challenging cases, especially those with microadenomas or non-lesional CD, desmopressin with IPSS aids in preoperative lateralization.