This multicenter randomized controlled trial plans to enroll primary aldosteronism (PA) patients who meet the following criteria: confirmed unilateral dominant secretion by adrenal vein sampling (AVS), willingness to undergo surgery, and coexisting chronic kidney disease (CKD). Participants will be randomly assigned in a 1:1 ratio to one of two groups. To determine whether short-term postoperative hydrocortisone replacement therapy (intervention group) is superior to conventional management (surgery within 7 days after AVS, control group) in terms of reducing the decline in estimated glomerular filtration rate (eGFR) at 12 months after surgery.

Inclusion Criteria:

1. Signed and dated informed consent form.
2. Age 18-75 years, any gender.
3. Confirmed diagnosis of primary aldosteronism (PA): positive PA screening test plus positive saline infusion test or captopril challenge test.
4. Imaging findings indicating unilateral adrenal lesion, with adrenal vein sampling (AVS) confirming unilateral dominant secretion consistent with the lesion side, and planned unilateral adrenalectomy.
5. Baseline eGFR 30-60 mL/min/1.73 m² OR positive proteinuria.

Exclusion Criteria:

1. Use of hydrocortisone within 3 months prior to AVS.
2. eGFR < 30 mL/min/1.73 m², or documented acute kidney injury (AKI) within the past 3 months.
3. Overt cortisol-secreting tumor (clinical Cushing's syndrome) or requirement for long-term hormone replacement therapy.
4. Severe proteinuria (24-hour urinary protein ≥ 3.5 g or ACR ≥ 300 mg/g).
5. NYHA class III-IV heart failure, or acute coronary syndrome or stroke within the past 3 months.
6. Severe allergy to hydrocortisone or history of serious adverse reactions to hydrocortisone.
7. Pregnancy, lactation, or planned pregnancy in the near future.
8. Active malignancy or life expectancy < 1 year.
9. Inability to tolerate surgery.
10. Inability to comply with follow-up as judged by the investigator, or any other condition deemed unsuitable for study participation.