Kamemura et al reported a model for identifying a patient with primary aldosteronism who may or who may not need adrenal vein sampling (AVS). The authors are from multiple institutions in Japan.
Patient selection: primary aldosteronism
Initial testing: abdominal CT to visualize both adrenal glands
Subtyping by CT was concordant with AVS in 56% of patients with bilateral adrenal tumors, 38% of patients with unilateral adrenal tumors and 89% of patients without adrenal tumors.
Rules:
(1) If a patient has an adrenal tumor on abdominal CT, then perform adrenal vein sampling.
(2) If a patient does not have an adrenal tumor on abdominal CT, then use score to determine if adrenal vein sampling is appropriate.
Parameters in a patient without adrenal tumor on CT:
(1) sex
(2) serum potassium in mmol/L
(3) aldosterone to renin ratio (ARR)
aldosterone to renin activity ratio =
= (aldosterone in pg/mL) / (renin activity in ng/mL per hour)
Parameter |
Finding |
Points |
sex |
female |
1 |
|
male |
0 |
serum potassium |
< 3.8 mmol/L |
0 |
|
>= 3.8 mmol/L |
1 |
ARR |
<= 550 |
1 |
|
> 550 |
0 |
total score =
= SUM(points for all 3 parameters)
Interpretation:
• minimum score: 0
• maximum score: 3
• The higher the score the greater the chance of bilateral disease.
• A patient with a score of 3 probably has bilateral disease and does not need adrenal vein sampling.
Score |
Sensitivity for Bilateral |
Specificity for Bilateral |
2 |
74% |
75% |
3 |
29% |
96% |
Performance:
• The area under the ROC curve is 0.80.
Specialty: Endocrinology