Significance of Computed Tomography and Serum Potassium in Predicting Subtype Diagnosis of Primary Aldosteronism.

CONTEXT: The number of centers with established adrenal venous sampling (AVS) programs for the subtype diagnosis of primary aldosteronism (PA) is limited.

OBJECTIVE

Aim was to develop an algorithm for AVS based on subtype prediction by computed tomography (CT) and serum potassium.

DESIGN

A multi-institutional retrospective cohort study in Japan.

PATIENTS: A total of 1591 patients with PA were classified into four groups according to CT findings and potassium status. Subtype diagnosis of PA was determined by AVS.

MAIN OUTCOME MEASURE: Prediction value of the combination of CT findings and potassium status for subtype diagnosis.

RESULTS

The percentages of unilateral hyperaldosteronism on AVS were higher in patients with unilateral disease on CT than those with bilateral normal results on CT (50.8% vs 14.6%, P < 0.01), and these percentages were higher in those with hypokalemia than those with normokalemia (58.4% vs 11.5%, P < 0.01). The prevalence and odds ratio for unilateral hyperaldosteronism on AVS were as follows: bilateral normal on CT with normokalemia, 6.2% (reference); unilateral disease on CT with normokalemia, 23.8% and 4.8 [95% confidence interval (CI), 3.1 to 7.2]; bilateral normal on CT with hypokalemia, 38.1% and 9.4 (95% CI, 6.2 to 14.1), and unilateral disease on CT with hypokalemia, 70.6% and 36.4 (95% CI, 24.7 to 53.5).

CONCLUSIONS

Patients with PA with bilateral normal results on CT and normokalemia likely have a low prior probability of a lateralized form of AVS and could be treated medically, whereas those with unilateral disease on CT and hypokalemia have a high probability of a lateralized form of AVS.