Adrenal venous sampling (AVS) is performed to distinguish the subtype of primary aldosteronism (PA). The clinical implication of contralateral suppression (CS; aldosterone/cortisolnondominant<aldosterone/cortisolperipheral) at AVS remains unclear. We aimed to investigate the clinical significance of CS and its impact on postoperative outcomes after unilateral adrenalectomy. In this retrospective observational multi-center study, we analyzed PA patients who underwent both successful adrenocorticotropin hormone-stimulated AVS and unilateral adrenalectomy. Successful cannulation was defined as the selectivity index (cortisoladrenal/cortisolperipheral) ≥3. Clinical and biochemical outcomes after unilateral adrenalectomy were evaluated based on the international Primary Aldosteronism Surgical Outcome consensus. Among 263 patients analyzed, 247 had CS (93.9%). Patients with CS had lower serum potassium levels, higher plasma aldosterone concentration, higher aldosterone-to-renin ratio (ARR), and larger adenoma size than those without CS. Those with CS showed significantly higher lateralization index than those without CS (P<0.001). Although postoperative blood pressure and ARR significantly decreased in those with CS, clinical and biochemical outcomes were comparable in both groups. When the cut-off value of age was determined using receiver operating characteristic (ROC) analysis, patients aged ≥50 years old with contralateral suppression index (CSI; the ratio between aldosterone/cortisolnondominant and aldosterone/cortisolperipheral) ≤0.26 had greater odds ratio (6.43; 95% confidence interval, 1.30 to 31.69) of incident chronic kidney disease than those aged <50 years with CSI >0.26 after adjusting for other factors.
