Background
Primary aldosteronism (P.A.) is a disease caused by excessive autonomous aldosterone from adrenal tumor or hyperplasia, characterized by the inhibition of the renin-angiotensin system, sodium retention, and excessive excretion of potassium and hydrogen [
1]. P.A. was regarded as a rare disease since it was first discovered by Conn in 1955 [
2] for it was found only in less than 1% of hypertensive patients [
3]. However, recent studies have noticed that P.A. accounts for 5% of hypertensive patients in primary care [
4], and the prevalence in patients with resistant hypertension has reached 17–23% [
5]. A study on the Chinese population with newly detected hypertension also profiled at least 4% of patients suffered P.A [
6]. Besides, P.A. is a significant cause of increased stroke risk, coronary artery disease, atrial fibrillation, ventricular hypertrophy, and renal damage [
7]. It could be assumed that most P.A. patients missed proper diagnosis and suffered cardiovascular damage, which may explain the limitation of traditional hypertensive drugs on resistant hypertension.
P.A. includes two main subtypes: aldosterone-producing adenoma (APA, accounting for about 35%) and bilateral adrenal hyperplasia (BAH, accounting for about 60%). Other rare subtypes include primary adrenal hyperplasia, family aldosteronism, and aldosterone-secreting adrenocortical carcinoma [
1,
8]. It is controversial whether P.A. patients should be treated with surgery or drugs [
9]. Unilateral adrenalectomy is suggested for most patients with adenoma or primary adrenal hyperplasia, which statistically satisfied the goal of clinical and laboratory remission [
10,
11]. However, anti-RAAS drugs and glucocorticoids are more recommended for BAH or family aldosteronism patients [
12].
Raising the accuracy of diagnosis and subtyping is extremely important for P.A. patients. Screening of P.A. is based on the aldosterone to renin ratio (ARR), and people with abnormally elevated ARR should be screened by further oral salt loading or captopril confirmatory tests [
13]. P.A. subtyping test is also an essential, although difficult and challenging, step [
13]. Adrenal venous sampling (AVS) was now regarded as the gold standard for P.A. subtyping but only performed in limited centers [
12,
14]. Our team was experienced in this technique. Recently, we have developed a computed tomography image fusion, coaxial guidewire technique, and fast intraprocedural cortisol testing (CCF) technique, which significantly increased the success rate of AVS to 98% and shortened the whole procedure time [
15]. Moreover, we are still committed to exploring a more optimized AVS procedure.
AVS outcome was interpreted by comparing aldosterone levels in the adrenal venal of the dominant and nondominant side, which could be affected by the position change [
16]. Before AVS without corticotropin injection, patients were suggested to keep a supine position to avoid aldosterone fluctuation [
13,
17]. However, the length of supine time before AVS had no established standard, although authoritative guidelines recommend recumbency times ranging from 1 h to overnight [
13,
17]. In previous work, we chose 1–2 h of supine time as the guideline suggested [
17]. We observed many problems were caused by excessive supine time, such as patient’s urinary retention and anxiety, while reduced supine time was found to be more friendly for these patients.
The cortisol level of patients is also an important factor affecting the selective index (S.I.) during AVS. A cohort study showed that at least 15 min of rest before blood sampling was enough to minimize the stress effect and guarantee a satisfactory outcome [
18]. Thus, we speculate that 15-min supine time is enough to minimize the fluctuation of aldosterone and cortisol fluctuation caused by position change and preoperative stress.
However, evidence of the most optimal supine time before AVS still lacks, which could simultaneously improve patient satisfaction and compromise the success rate. We expect that the shortened supine time will improve patient experience and ensure the success rate at the same time.