Left-versus-right-adrenal-volume ratio as a screening index before adrenal venous sampling to identify unilateral primary aldosteronism patients.

Objectives: The current study aimed to investigate the value of the computed tomography-based left-versus-right adrenal gland volume ratio (L/Rv) in screening patients with unilateral primary aldosteronism.

Methods: The current study recruited 114 patients who underwent successful adrenal venous sampling (AVS) and adrenal computed tomography at West China Hospital of Sichuan University. The patients were divided into three groups according to the AVS results: AVS-left, AVS-bilateral, and AVS-right primary aldosteronism. The volumes of the left and right adrenal glands were semiautomatically calculated. The L/Rv of each patient was computed, and its value in identifying unilateral primary aldosteronism was analyzed.

Results: The mean value of the L/Rv was larger in AVS-left patients and smaller in AVS-right patients than that in AVS-bilateral patients. In AVS-left primary aldosteronism patients, the cutoff value of the L/Rv with the highest Youden index was 1.344 [area under the curve (AUC) 0.851, sensitivity 80.0%, specificity 78.1%]. The optimal cutoff value was 1.908, of which 46.0% (23/50) of AVS-left primary aldosteronism patients could be identified (specificity 100.0%). In AVS-right primary aldosteronism patients, the cutoff value of the L/Rv with the highest Youden index was 1.267 (AUC 0.868, specificity 72.8%, sensitivity 87.9%). The optimal cutoff value was 0.765, of which 27.3% (9/33) of AVS-right primary aldosteronism patients could be identified (specificity 100.0%). Patients with L/Rv more than 1.908 or less than 0.765 had higher complete success rate postsurgery.

Conclusion: Although not perfect, the L/Rv is an applicable index to screen unilateral primary aldosteronism patients for surgery. Primary aldosteronism patients, even those aged more than 35 years, with an L/Rv more than 1.908 or less than 0.765 can be spared AVS before surgery.