Re: ‘‘Selective Use of Adrenal Venous Samplingin the Lateralization of Aldosterone-ProducingAdenomas

Unilateral adrenalectomy in patients with aldosterone-

producing adenoma or unilateral primary adrenal

hyperplasia results in normalization of hypokalemia and

aldosterone levels in all; hypertension is improved in all

and is cured in approximately 30% to 60% of patients. In

bilateral idiopathic hyperplasia and glucocorticoid reme-

diable aldosteronism, unilateral or bilateral adrenalec-

tomy seldom corrects the hypertension. Bilateral

idiopathic hyperplasia and glucocorticoid remediable

aldosteronism should be treated medically. Adrenal

venous sampling is the reference standard test to differ-

entiate unilateral from bilateral disease in patients with

primary aldosteronism.1 Adrenal venous sampling is

performed well at a limited number of centers where the

test is conducted by dedicated, experienced radiologists;

thus, the risk of not cannulating the right adrenal vein is

minimized. As an invasive procedure, adrenal venous

sampling is not without potential sequelae that include

groin hematoma, adrenal vein dissection, adrenal gland

hemorrhage, and adrenal infarction. In experienced cen-

ters, rates of such complications are quite low and rarely

of any lasting clinical consequence.1 However, in view of

the limited availability of accurate and safe adrenal vein

sampling, some centers have advised alternate pathways

to the subtype diagnosis of the patient with primary

aldosteronism.

As described by Tan and colleagues (DOI: 10.1007/

s00268-005-0622-8), 52 of 65 (80%) patients with primary

aldosteronism who underwent laparoscopic adrenalec-

tomy had their adrenal tumors lateralized based solely on

CT and/or MRI. The remaining 13 (20%) patients had

doubtful lateralization based on conventional imaging. Of

these 13 patients, eight underwent adrenal venous

sampling. All 13 patients with doubtful lateralization

eventually had laparoscopic adrenalectomy. With this

selective approach, the hypokalemia was cured in 98% of

patients, the aldosteronism was cured in 85% of patients,

and the hypertension improved or resolved in 83% of

patients. Except for the suboptimal aldosteronism cure

rate, these results are comparable to other centers that

use adrenal venous sampling more liberally.2

The authors performed 91 consecutive adrenalecto-

mies for primary aldosteronism during the study period,

yet they only analyzed approximately 70% of the cases

due to ‘‘insufficient clinical information.’’ We must assume

that 30% of the cases were excluded from their retro-

spective analysis due to lack of data such as blood

pressure measurements, medication(s), serum potas-

sium levels, and/or plasma aldosterone concentrations.

Clinical data from this sizable segment of patients ex-

cluded from the consecutive series could have easily al-

tered the conclusions derived from the study group.

Five of the thirteen patients with doubtful lateraliza-

tion on CT or MRI who had laparoscopic adrenalectomies

(but not adrenal venous sampling) had the following

outcomes: all five patients remained hypertensive, and

only one had a reduction in medication requirements. The

aldosterone cure rate in this subgroup was only 67% in

the non-adrenal venous sampling arm; however, the

aldosterone cure rate was only known for three of the five

patients. All five patients were seemingly cured of their

hypokalemia, but how extensive was the follow-up? Was

a single sample drawn shortly after surgery or did serial

rechecks over many months take place? Why would you

offer adrenalectomy without adrenal venous sampling

data in any patient with doubtful lateralization by con-

ventional imaging?

We concur with the authors’ algorithm for diagnostic

workup, although we would expand this to include all

patients over the age of 40 years due to the increased

prevalence of nonfunctioning cortical adenomas in this

age group. The perception by some is that clinicians at

Mayo Clinic utilize adrenal venous sampling at the ‘‘drop

of a hat,’’ is not a reflection of true practices. The ap-

proach at Mayo Clinic is to select patients for adrenal

venous sampling based on their degree of aldosterone

excess, their age, their desire for surgical treatment,

and their CT findings.1 Only 30% of patients with pri-

� 2006 by the Societe Internationale de Chirurgie World J Surg (2006) xx: 886–887

Published Online: 21 April 2006 DOI: 10.1007/s00268-006-0101-x

INVITED COMMENTARY

mary aldosteronism have a unilateral source of aldo-

sterone excess (i.e., an aldosterone-producing adenoma

and primary adrenal hyperplasia [unilateral hyperpla-

sia]). Present generation CT scanners with thin cuts

through the adrenal glands demonstrate subtle findings

that can be difficult to interpret. Certainly, if a greater

than 1-cm hypodense cortical adenoma with a normal-

appearing contralateral gland is identified in a young

patient (where a nonfunctioning cortical adenoma is

unlikely) with primary aldosteronism, adrenal venous

sampling is not necessary. However, when the bio-

chemical diagnosis is secure and CT imaging shows

bilaterally normal or abnormal adrenals, or adrenal limb

thickening is unilateral or bilateral in the appropriate

clinical scenario, adrenal venous sampling, in our

opinion, is mandatory. Our most recent series of 203

consecutive patients who were selected for adrenal

venous sampling (1990 to 2003) based on the degree of

aldosterone excess, age, desire for surgical treatment,

and CT findings revealed that 42 patients (21.7%) with

normal CT or bilateral micronodular findings proved to

have unilateral adrenal disease and would have been

incorrectly excluded from adrenalectomy – a subgroup

that Tan and colleagues have not addressed in their

surgery-based study.1 In addition, 48 (24.7%) of the

patients in our adrenal venous sampling series would

have had an unnecessary or inappropriate adrenalec-

tomy based on the CT findings alone. Despite this

‘‘liberal’’ approach to adrenal venous sampling, we

performed this procedure in only 21% of our overall

patient population with confirmed primary aldosteronism

during that time period.

While we do share the same general clinical ap-

proach (conservative versus liberal) with Tan and col-

leagues, we disagree with their conclusions that are

based on their limited follow-up data and lack of knowl-

edge of primary aldosteronism subtypes in patients at

their institution who did not have surgery during the same

time period that this study was completed.

REFERENCES

1. Young WF Jr, Stanson AW, Thompson GB, Grant CS,

Farley DR, van Heerden JA. Role for adrenal venous

sampling in primary aldosteronism. Surgery 2004;136:

1227–1233.

2. Sawka AM, Young WF Jr, Thompson GB, Grant CS,

Farley DR, Leibson C, van Heerden JA. Primary aldos-

teronism: Factors associated with normalization of blood

pressure after surgery. Ann Intern Med 2001;135:258–261.

Geoffrey B. Thompson, MD,

William F. Young Jr, MD

Mayo Clinic College of Medicine,

200 First Street SW

Rochester, MN55905,

USA

e-mail: Thompson.geoffrey@may.edu

Invited Commentary: 887