Assessment of bilateral inferior petrosal sinus sampling in the diagnosis and surgical treatment of the ACTH-dependent Cushing's syndrome: a comparison with other tests.

BACKGROUND: Bilateral inferior petrosal sinus sampling (BIPSS), currently, is the gold standard test for the differential diagnosis of Cushing's syndrome (CS), but few data are available on the efficacy and accuracy of BIPSS in the qualitative diagnosis of ACTH-dependent CS and lateralization of Cushing's disease (CD); especially, the evaluation of BIPSS in all CD patients with transsphenoidal surgery (TSS). As a result, we investigated whether such invasive test compared other noninvasive tests may affect the efficacy and accuracy of diagnosis and TSS treatment in ACTH-dependent CS.

OBJECTIVE: We investigated the efficacy and lateralized accuracy of diagnostic and therapeutic of BIPSS in ACTH-dependent CS.

SETTINGS: A retrospective analysis was conducted at a single care center in Ruijin Hospital, Shanghai City.

PARTICIPANTS: CD was confirmed by histopathology in one hundred and nineteen patients, include sixty-four patients with BIPSS procedure; and ectopic ACTH syndrome (EAS) also was histological confirmed in five patients. MAIN INTERVENTIONS AND OUTCOMES: Sixty-nine patients were all administrated with BIPSS test. Additionally, other noninvasive tests included endocrine examinations, low and high dose dexamethasone suppression test (LDDST and HDDST); imagine examinations include magnetic resonance imaging (MRI) and positron emission tomography and computerized tomography (PET-CT).Gradients of inferior petrosal sinus (IPS) to peripheral (IPS/P) ACTH were calculated before and after BIPSS procedure completed five minutes.

RESULTS: In patients with proven pituitary cases, stringent response criteria in MRI and HDDST testing were fully by 51.6% and 60.3% respectively. While BIPSS, gave direct evidence of CD in 90.6% of these cases. The sensitivity for a basal IPS/P gradient greater than 2 was 89.1%, with 100% specificity and a diagnostic accuracy of 87.5%. A subgroup of 14 patients (all were CD) had contradictory responses to routine test with HDDST; while the sensitivity, specificity and accuracy of BIPSS were 100% respectively. Compared with the MRI and DST, we accepted Receiver Operating Characteristic (ROC) curve analysis showed that BIPSS performance is the best efficacy diagnosis tool in CS. In total, 57 of 64 patients with CD had an IPS/P gradient greater than 2, resulting in the sensitivity, specificity and diagnostic accuracy are 90.5%, 100%, 95.2% respectively. Additionally, the accuracy value of BIPSS in indicating dominant side should also be stressed in adenoma lateralization of CD. Finally, BIPSS test contributed most in the remission efficacy of TSS; then remission rate of underwent BIPSS group is 92.2% compared to the rate of 80% in without BIPSS group (p<0.01), Compared with other noninvasive tests, turn out the highest accuracy rate in remission.

CONCLUSIONS: The application of BIPSS is associated with efficacy and accuracy of ACTH-dependent CS and lateralization of CD, what's more, all above, we can conclude that BIPSS is associated with the surgical therapy in CD patients. Therefore, BIPSS dedicate to the diagnosis, treatment and intraoperation administration of ACTH-dependent CS.