This study aim to understand whether the length of preoperative supine time would affect the AVS outcome.

Primary aldosteronism (PA) is the most common form of secondary hypertension, accounting for 5% of hypertensive patients and 17-23% in patients with resistant hypertension. Compared to the primary hypertension, PA is more prone to cause severe organ damage and even early death. Adrenal venous sampling (AVS) is an effective confirmatory test for subtyping unilateral and bilateral adrenal hyperplasia, helping doctors to make an accurate decision between surgery or medication. Supine in bed before AVS is recommended for a desirable result of AVS according to guidelines. However, investigating study about the most optimal preoperative supine time before AVS is lacking. This is a single-center prospective randomized controlled study. 120 patients diagnosed as PA and with willing for further AVS examination will be included. Participants will be randomly allocated to 15-min supine time group or 2-hours supine time group. The primary outcomes are the degrees of clinical and laboratory remission (blood pressure, type and dose of antihypertensive drugs, serum potassium, orthostatic ARR). The secondary outcomes are the technical success rate and adverse event of AVS (selective index≥2 is considered as successful surgery without corticotropin stimulate). Discussion: Primary aldosteronism is an intractable public health problem, and many techniques including AVS have been developed to correctly identify this disease. This study will help to understand whether the length of preoperative supine time would affect the diagnostic efficacy of AVS, and thus help to formulate a more reasonable AVS procedure.

Inclusion Criteria:

1. Patients are clinically diagnosed as primary aldosteronism with ARR≥37 (PAC showed as pg/ml, renin showed as μIU/mL) and passed through PA confirmatory tests (PAC-post CCT>110pg/ml, PAC-post SSIT >80pg/ml, or PAC-post FST>60pg/ml). PAC: plasma aldosterone concentration;
2. Patients with willing for AVS;
3. Age 18 or above, male or female, with legal capacity.

Exclusion Criteria:

1. Patients with suspected adrenocortical carcinoma or pheochromocytoma;
2. Patients with high risk of adrenal surgery;
3. Patients have been subtyping to glucocorticoid-suppressible hyperaldosteronism or familial hyperaldosteronism type III;
4. Patients were diagnosed as Cushing syndrome or subclinical Cushing syndrome;
5. Patients were treated with glucocorticoids recently;
6. Patients with whole body or venipuncture area infection;
7. Patients with venous access thrombosis;
8. Patients are allergic to iodine;
9. Patients with X-ray contraindications;
10. Patients with coagulation dysfunction;
11. Patients are unable to cooperate and follow-up.

Patients and investigators cannot be blinded due to the type of study. To minimize the potential influence of this limitation, we will assign the most professional vascular doctor to perform the same operation on the two groups of patients, and statisticians will be blind.