Validation of a new non-invasive predictive score (KASAI) for primary aldosteronism subtyping.

Introduction: Adrenal venous sampling (AVS) is considered the gold standard test for primary aldosteronism (PA) subtyping. Considering the limited availability of this challenging procedure, we propose a noninvasive score predicting unilateral (UPA) or bilateral (BPA) form of PA in order to reduce the need for AVS.

Material and methods: The score was retrospectively developed from a cohort of 72 patients who underwent AVS (21 patients with BPA and 51 with UPA) at Cliniques Universitaires Saint Luc between 1993 and 2021. Another multicenter cohort of 130 patients who underwent AVS (67 patients with BPA and 63 with UPA) served as external validation.

Results: Four predictive parameters of UPA highlighted by logistic regression analysis were integrated into the KASAI score: minimal serum potassium value, supine resting aldosteronemia, aldosteronemia at the end of the saline infusion test, and results of adrenal imaging. Depending on the results, 0, 1, or 3 points were assigned to each parameter. In both cohorts, a score greater than 9/12 identified UPA and a score less than 4/12 identified BPA with 100% specificity, while performing AVS remained indicated for scores between 4 and 9. The score may have avoided AVS in 40% of patients in the primary cohort and in 42% of patients in the validation cohort. The area under the ROC curve for discrimination of UPA from BPA was 0.81 (95% CI, 0.70-0.90) in the primary cohort and 0.86 (95% CI, 0.80-0.90) in the validation cohort.

Conclusion: We propose a new biological-radiological score that could simplify the diagnostic assessment of PA.