Role of unilateral‐cannulating adrenal venous sampling for the subtyping of primary aldosteronism for adrenalectomy: Experience from a low‐volume center

AbstractBackgroundCurrent guidelines recommend adrenal venous sampling (AVS) for subtyping primary aldosteronism (PA). However, bilateral adrenal cannulation failure is common especially at low‐volume centers. The role of unilateral‐cannulating AVS in selecting patients for unilateral adrenalectomy is unclear.MethodsFifty consecutive patients underwent AVS between 2009 and 2023 and thirty‐three (66%) underwent unilateral adrenalectomy. We defined unilateral PA (uPA) by the normalized plasma aldosterone and the aldosterone–renin ratio following unilateral adrenalectomy. We examined the effectiveness of unilateral‐cannulating AVS in identifying uPA.Results88%, 50%, and 48% of patients had the left, right, and bilateral adrenal veins successfully cannulated, respectively. Among patients with bilateral successful cannulation, a lateralization index (LI) > 4 provided a sensitivity of 100% and a positive predictive value (PPV) of 86.7% for uPA. Thresholds for the contralateral suppression index (CSI) and relative aldosterone secretion index (RASI) were derived from this subgroup and applied to the entire cohort. CSI <0.5 demonstrated a sensitivity of 76.5% and PPV of 92.9% for uPA, whereas RASI >2.4 showed a sensitivity of 85.0% and PPV of 94.4% for uPA. With CSI <0.5 or RASI >2.4 combined, a higher PPV (95.5%) was achieved when compared to computed tomography and iodocholesterol scintigraphy (86.2% and 62.5%, respectively).ConclusionDespite unsuccessful bilateral cannulation, our study confirms that unilateral‐cannulating AVS can effectively select patients for unilateral adrenalectomy based on a combination of CSI or RASI criteria.