dromlakhani Determine successful catheterization in adrenal venous sampling using selectivity index
STEP 1 — Gather Information
Collect cortisol concentration from the right adrenal vein, left adrenal vein, and inferior vena cava (or peripheral vein), and record whether ACTH stimulation was administered during sampling.
STEP 2 — Rule In / Rule Out
If ACTH stimulation was used, apply the selectivity index cut‑off of ≥5; otherwise apply the cut‑off of ≥2.
STEP 3 — Classify or Stratify
Calculate the selectivity index (SI) for each adrenal vein as cortisol adrenal vein ÷ cortisol IVC; label the vein selective if SI meets the applicable cut‑off, otherwise non‑selective.
STEP 4 — Decide
Declare catheterization successful for a given adrenal vein when its SI meets the cut‑off; if both veins are non‑selective, consider catheter repositioning or repeat AVS.
Clinical Guardrails / Mimics / Pitfalls
Be aware of cortisol fluctuations, dilution, or drainage veins that can falsely lower SI; cortisol co‑secretion may suppress contralateral cortisol and affect SI interpretation; do not rely on SI alone for lateralization—use lateralization index after confirming selectivity; ensure simultaneous sampling to avoid timing artifacts.
Concrete Clinical Example
During ACTH‑stimulated AVS, right adrenal vein cortisol 450 ng/mL, IVC cortisol 80 ng/mL gives SI = 5.6 (≥5) → selective; left adrenal vein cortisol 120 ng/mL, IVC 80 ng/mL gives SI = 1.5 (<5) → non‑selective; right‑sided catheterization deemed successful, proceed with lateralization assessment.
Source: Japan Endocrine Society clinical practice guideline for the diagnosis and management of primary aldosteronism 2021, Japan Endocrine Society, 2022
TODO: consider adding scripts/calc.py for the jes-pa-avs-catheterization-success calculator