View
213
Download
1
Category
Preview:
Citation preview
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
Recommended