Selective Use of Bilateral Inferior Petrosal Sinus Sampling in Patients with Adrenocorticotropin-Dependent Cushing's Syndrome Prior to Transsphenoidal Surgery

Context: Few data are available on the selective use of bilateral inferior petrosal sinus sampling (BIPSS) in the presurgical evaluation of patients with ACTH-dependent Cushing's syndrome, so we investigated whether its use only in patients without a clear adenoma on magnetic resonance imaging and/or inconsistent biochemical testing affected remission and long-term outcome after surgery in patients with Cushing's disease (CD). Setting: This was a retrospective review of patients treated for CD by one pituitary neurosurgeon at tertiary medical centers in New York City. Patients: A total of 193 consecutive adult patients who underwent initial transsphenoidal surgery (TS) for presumed CD between 1987 and 2005 were included. Main Outcome Measures: We examined preoperative pituitary imaging and biochemical data, results of BIPSS and surgical pathology, and outcome based on biochemical tests after initial TS and long term after subsequent therapies. Results: Remission rate after the first TS was 80.8% overall, 79.1% in the BIPSS group (n = 105), and 83.0% in the No-BIPSS group (n = 88). Recurrences occurred in 13.5% after the first TS at a mean of 4.8 +/- 3.5 yr (range, 0.7-12.4 yr) with no difference between BIPSS and No-BIPSS groups. Longterm remission was achieved after surgeries and radiotherapy in 85% (86.7% of BIPSS group, 83.0% of No-BIPSS group). CD was ultimately confirmed in all but one patient in each group. Conclusions: Selective use of BIPSS in the preoperative evaluation of patients with presumed CD did not lead to misdiagnosis in the No-BIPSS group or adversely affect remission rates or long-term outcome. (J Clin Endocrinol Metab 93: 4624-4632, 2008)