Primary aldosteronism patients with bilateral adrenal vein sampling success achieve better outcomes through unilateral adrenalectomy

Abstract

Background: Adrenal vein sampling (AVS) is the gold standard for diagnosing the dominant side in patients with primary aldosteronism (PA). CYP11B2 encodes aldosterone synthase. The aim of this study was to investigate the prognosis of dominant-side adrenalectomy in patients with PA identified by AVS in the context of aldosterone synthase expression in the postoperative pathology of those patients.

Methods: This retrospective study included 73 PA patients who underwent AVS followed by unilateral adrenalectomy. Patients were categorized into AVS bilateral success group, AVS unilateral success group, and AVS bilateral failure group based on their AVS status. Immunohistochemistry (IHC) for CYP11B2 was combined with postoperative pathology in these patients, and the clinical and biochemical prognosis of these patients was assessed 6 months after adrenalectomy.

Results: Between September 2023 and September 2024, 73 patients underwent unilateral adrenalectomy guided by AVS at our institution, with CYP11B2 IHC successfully performed in 63 cases. Among these, 21 patients (33.33%) achieved bilateral AVS success, 20 (31.75%) demonstrated unilateral AVS success, and 22 (34.92%) exhibited bilateral AVS failure. Pathological analysis of the bilateral AVS success group revealed aldosterone-producing adenoma (APA) in 12 cases, aldosterone-producing micronodule (APM) in 1, multiple-aldosterone-producing micronodules/nodules (MAPM/MAPN) in 2, aldosterone-producing diffuse hyperplasia (APDH) in 1, APA with MAPM in 3, and APA with APDH in 2. In this group, complete and partial clinical success rates were 47.62% (10/21) and 52.38% (11/21), respectively, while biochemical success rates reached 95.24% (20/21) for complete and 4.76% (1/21) for partial success. The unilateral AVS success cohort included APA (n=8), aldosterone-producing nodule (APN) (n=2), MAPM/MAPN (n=3), APA with MAPM (n=4), APA with APDH (n=2), and 1 CYP11B2 IHC-negative lesion, with clinical success rates of 40.00% (8/20) complete and 60.00% (12/20) partial, alongside 90.00% (18/20) complete and 10.00% (2/20) partial biochemical success. The bilateral AVS failure group comprised APA (n=8), MAPM/MAPN (n=1), APA with MAPM (n=5), APA with APDH (n=2), and 6 CYP11B2 IHC-negative lesions, demonstrating 36.36% (8/22) complete, 50.00% (11/22) partial, and 13.64% (3/22) no clinical success, with biochemical outcomes of 72.73% (16/22) complete, 18.18% (4/22) partial, and 9.09% (2/22) no success. Notably, bilateral AVS success correlated with significantly superior biochemical outcomes compared to bilateral failure (P=0.045).

Conclusions: Adrenalectomy guided by AVS yields better outcomes in patients with PA when AVS is successful on both sides compared to those with bilateral AVS failure. The source of excess aldosterone secretion on the dominant side identified by AVS is not necessarily an APA/APN. It may also include MAPM/MAPN, diffuse adrenal cortical hyperplasia, and various complex combined conditions. In patients with bilateral AVS failure, adrenal specimens more frequently exhibit negative immunohistochemical staining for CYP11B2.

Keywords: CYP11B2; Primary aldosteronism (PA); adrenal vein sampling (AVS); dominant side; prognosis.

Figure 1

CT and enhanced CT of adrenal mass. (A) A non-contrast CT scan revealing a mass in the left adrenal gland. (B,C) The enhanced phase and excretory phase imaging of the left adrenal mass, respectively. The red arrows point to the area of the patient’s left adrenal lesion. (D) The right adrenal gland of the same patient. (E,F) The enhanced phase and excretory phase imaging of the right adrenal gland, correspondingly. CT, computed tomography.

Figure 2

Adrenal vein sampling. (A,B) Images of right adrenal vein blood collection with catheter placed in the right adrenal vein, respectively. (C,D) Images of left adrenal vein blood collection with catheter placed in the left adrenal vein, respectively.

Figure 3

Postoperative pathology and immunohistochemistry. (A) A postoperative pathology, HE-stained image of a patient with PA. (B) Image of CYP11B2 IHC staining in this patient, classified as APA by HISTALDO. The magnification is 4×. APA, aldosterone-producing adenoma; HE, hematoxylin and eosin; HISTALDO, histopathology of primary aldosteronism; IHC, immunohistochemistry; PA, primary aldosteronism.

Figure 4

All pictures show the pathology of PA patients with CYP11B2 IHC staining. According to HISTALDO typing, the figures are labeled as follows: (A) APA, (B) APA combined with MAPM, (C) APN, (D) MAPM/MAPN, (E) MAPM, and (F) APDH. APA, aldosterone-producing adenoma; APDH, aldosterone-producing diffuse hyperplasia; APN, aldosterone-producing nodule; HISTALDO, histopathology of primary aldosteronism; IHC, immunohistochemistry; MAPM, multiple-aldosterone-producing micronodule; MAPN, multiple-aldosterone-producing nodule; PA, primary aldosteronism.

Figure 5

Prognosis of subgroups of PA patients undergoing AVS. Horizontal coordinates are the different AVS conditions as well as the different PASO prognoses. Vertical coordinates are the number of patients. According to the PASO evaluation, the red bars represent the amount of patients who were for no success, the yellow bars represent the patients who were partially successful, and the green bars represent the patients who were completely successful. The three bars on the left side of the annotated shape are the number of patients who failed AVS bilaterally, the three bars in the middle are the patients who had unilateral success with AVS, and the three bars on the right side are the patients who had bilaterally success with AVS. (A) Different biochemical prognosis of patients with different AVS after unilateral adrenalectomy in PA patients. (B) Different clinical prognosis of patients with different AVS after unilateral adrenalectomy in PA patients. AVS, adrenal vein sampling; PA, primary aldosteronism; PASO, primary aldosteronism surgical outcome.

Figure 6

Relationship between AVS dominant side by side and pathologic IHC. The horizontal coordinate is the division of patients into APA/APN group, APM/MAPM/APDH/APA + MAPM/APA + APDH group, and negative group according to different pathologic types. The vertical coordinate is the number of patients with different pathologic types. APA, aldosterone-producing adenoma; APDH, aldosterone-producing diffuse hyperplasia; APM, aldosterone-producing micronodule; APN, aldosterone-producing nodule; AVS, adrenal vein sampling; IHC, immunohistochemistry; MAPM, multiple-aldosterone-producing micronodule.