Effect of Collection Timing on Selectivity Index in unstimulated adrenal venous sampling: discovery and validation

Monday, March 31, 2025

3:54 PM – 4:03 PM CT

Location: Music City Center, 202 BC

Presenting Author(s)

Mohammed Elkholy, MD

Postdoctoral research fellow
The Laboratory for Minimally Invasive Tumor Therapies, Department of Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, United States of America, United States

Author/Co-author(s)

AM

Ahmad Maaly, MD

Postdoctoral Research Fellow
Beth Israel Deaconess Medical Center/Harvard Medical School, United States
MF

Mohamed Farghaly, MD

Postdoctoral research fellow
The Laboratory for Minimally Invasive Tumor Therapies, Department of Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, United States of America., United States
SM

Sanan Mahrokhain, BS

Postdoctoral research fellow
Brigham and Women's Hospital, United States
LT

Laura Tsai, BS

Postdoctoral research fellow
Brigham and Women's Hospital, United States
IH

Isabelle Hanna, BS

Postdoctoral research fellow
Brigham and Women's Hospital, United States
AV

Anand Vaidya, MD

Endocrinologist, Director, Center for Adrenal Disorders
Brigham and Women's Hospital, United States
Barry Sacks, MD

Faculty Interventional Radiologist
Beth Israel Deaconess Medical Center - Harvard Medical School, United States
Marwan Moussa, MD

Instructor of Radiology
Beth Israel Deaconess Medical Center/ Harvard Medical School, United States

Purpose: To determine the impact of unstimulated peripheral sample collection timing on the selectivity index (SI) and overall success of adrenal venous sampling (AVS) for primary aldosteronism (PA) subtyping.

Materials and Methods: The study was divided into an observational retrospective study and a prospective validation study. The retrospective study included 74 patients undergoing AVS pre- and post-ACTH stimulation for PA subtyping. Patients were divided into two groups: 1) “30 min-pre” where peripheral samples collected 30 minutes before adrenal venous sampling and 2) “1 min-post” with samples collected 1 minute post-adrenal venous sampling. An SI below 2 was classified as false negative, and an SI above 2 as true positive. Data was analyzed using Chi-squared test with a two-sided P < 0.05 indicating statistical significance. For validation, 27 patients were enrolled prospectively. In each patient, two peripheral samples were collected 30 minutes before and 1 minute after venous sampling. Cortisol and aldosterone levels were compared using the Wilcoxon matched-pair signed rank test, with a two-sided P < 0.05 indicating statistical significance.

Results:

Retrospectively, 38% of patients in the “30 min-pre” group had false negative results for SI in the right adrenal vein, compared to 14% in the “1 min-post” group (P = 0.017). On the left side, 17 patients in the “30 min-pre” group had a SI < 2 but ≥ 5 post-stimulation, with a false negative rate of 17/37. In the “1 min-post” group, 5 patients had false negatives, with a rate of 5/37. Chi-square = 9.315, P = 0.002. In the prospective study, peripheral cortisol concentration 1 min post decreased by 28% compared to 30-minute pre (median, 6.4 μmol/L to 4.6 μmol/L; P < 0.001). The SI increased by 40% on both sides (P < 0.001). Fewer patients had successful left adrenal vein cannulation before adrenal vein sampling (78%) compared to after (93%), P = 0.16. Also, fewer patients had successful left adrenal vein cannulation before adrenal vein sampling (70%) than after (78%), P = 0.46.

Conclusion:

Collecting peripheral samples 30 minutes before adrenal venous samples negatively affects SI compared to peripheral samples collected 1 minute after adrenal veins sampling. To maximize chances of successful AVS peripheral samples should be collected just after adrenal venous sampling.