Determine When Adrenal Venous Sampling May Be Skipped in PA
STEP 1 — Gather Information
Confirm primary aldosteronism via positive ARR and confirmatory test. Collect age, serum potassium (spontaneous hypokalemia), plasma aldosterone concentration (marked excess), and adrenal CT characteristics (unilateral lesion with cortical adenoma features: size <4 cm, homogeneous attenuation, no irregular margins).
STEP 2 — Rule In / Rule Out
Is the patient younger than 35 years? If no, proceed to adrenal venous sampling. If yes, continue to assess additional criteria.
STEP 3 — Classify or Stratify
Does the patient have spontaneous hypokalemia, marked aldosterone excess (e.g., PAC >20 ng/dL), and a unilateral adrenal lesion on CT with features consistent with a cortical adenoma? If all three are present, AVS may be omitted. If any criterion is missing, proceed to AVS.
STEP 4 — Decide
If criteria are met, proceed directly to unilateral laparoscopic adrenalectomy without adrenal venous sampling. Otherwise, perform adrenal venous sampling to lateralize aldosterone excess before surgery.
Clinical Guardrails / Mimics / Pitfalls
Ensure CT is interpreted by an experienced radiologist to avoid misclassifying hyperplasia or carcinoma as adenoma. Do not skip AVS if the lesion is >4 cm, irregular, or bilateral. Biochemical confirmation of PA is required; do not rely on ARR alone. Avoid in patients with concomitant medications that alter aldosterone/renin. Remember that age <35 alone is insufficient; all three criteria must be satisfied.
Concrete Clinical Example
A 32‑year‑old woman with hypertension and spontaneous hypokalemia (K+ 3.0 mmol/L) has PAC 35 ng/dL, suppressed PRA, and ARR >50. Adrenal CT shows a 1.5 cm homogeneous left adrenal nodule without contralateral lesion. She meets all criteria and proceeds to left laparoscopic adrenalectomy without AVS.
Source: The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2016, doi:10.1210/jc.2015-4061