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Young patients with primary aldosteronism may avoid adrenal vein sampling
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Young adult patients with a typical clinical presentation of primary aldosteronism can be spared invasive and expensive adrenal vein sampling and expect similar outcomes by using CT imaging to diagnosis disease subtype, according to findings from a retrospective study conducted in Japan.
“The number of centers with successful [adrenal vein sampling] programs is limited due to the degree of technical expertise required, the invasive nature of the test and its high cost,” Mitsuhide Naruse, MD, PhD, of the department of endocrinology and metabolism at Kyoto Medical Center in Kyoto, Japan, and colleagues wrote in the study background. “Therefore, alternative diagnostic methods that obviate the necessity of [adrenal vein sampling] without sacrificing accuracy are needed.”
Naruse and colleagues analyzed data from 358 patients with primary aldosteronism with hypokalemia, elevated aldosterone and unilateral disease on CT imaging, who went on to undergo successful adrenal vein sampling (AVS), using data from the Japan Primary Aldosteronism Study between 2006 and 2016. Researchers compared the concordance of diagnosis between CT imaging and AVS findings stratified by age (< 35 years, 35 to 40 years, 40 years) and considered surgical outcomes to assess the accuracy of CT imaging findings among patients in which AVS indicated bilateral aldosteronism.
Researchers observed a concordance of diagnosis between CT imaging and AVS in 90% of patients younger than 35 years, in 79% of patients aged 35 to 40 years and in 69% of patients aged at least 40 years, suggesting a reduction in sensitivity of CT imaging in patients aged at least 40 years with hypokalemia and elevated plasma aldosterone concentration (P for trend < .01).
Additionally, researchers did not observe cases of contralateral unilateral hyperaldosteronism on AVS when compared against CT imaging in patients younger than 40 years, whereas 2% of patients aged at least 40 years showed contralateral unilateral hyperaldosteronism by AVS vs. CT imaging.
Within the cohort, 11 young adult patients showed discordance between CT imaging and AVS; among those, the three patients younger than 35 years showed surgical benefit. The same benefit was shown in only three of eight patients aged 35 to 40 years due to a lack of surgical outcome data.
The diagnostic accuracy of CT findings was 100% in patients younger than 35 years and 87% in patients aged 35 to 40 years, according to researchers.
“Our present study with a larger cohort than previous studies provided further evidence to support the recent suggestion from the Endocrine Society guideline on bypassing AVS in a subgroup of patients aged < 35 years who have spontaneous hypokalemia, aldosterone excess and unilateral adrenal disease on CT,” the researchers wrote. “In contrast, patients aged 35 to 40 years have the possibility of being spared AVS, but further validation is needed to provide conclusive evidence. The clinical relevance of our study was to clarify the subgroup that can avoid AVS before proceeding to unilateral adrenalectomy.” – by Regina Schaffer
Disclosures: The authors report no relevant financial disclosures.
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In 2016, the Endocrine Society published Guidelines on the Management of Primary Aldosteronism. These state that “younger patients (age < 35 years) with spontaneous hypokalemia, marked aldosterone excess, and unilateral adrenal lesions consistent with a cortical adenoma on CT scan may not need AVS before proceeding to unilateral adrenalectomy.” The Japan Primary Aldosteronism Study (JPAS), is a collaboration between 28 centers, 23 of which are represented in the present study, pooling their data, in this case to examine the Endocrine Society statement. Thirty patients under age 35 years, and 39 aged between 35 and 40 years, all of whom had hypokalemia and elevated plasma aldosterone, underwent CT, AVS and unilateral adrenalectomy, with the results then compared.
In 27 of the 30 patients under age 35 years, CT and AVS were concordant; the remaining three had a lateralization index (LI) of 3.5 to 3.6 and contralateral suppression, but were considered to be bilateral on AVS on the basis of an LI less than 4. This is a brave call, particularly as these three are quite distinct from most of the non-concordant subjects (n = 8) in the 35 to 40 age group where values ranged from 1.2 to 3.9; the highest also showed contralateral suppression. As the authors note, synacthen-facilitated AVS (bolus/infusion/both) “may abolish true lateralization gradients,” so that all of the younger group and some of the older (35-40 years) non-concordant patients might show a factitiously low LI and be truly unilateral.
In terms of outcomes, then, the data support the recommendations of the Endocrine Society. In patients under 35 years, it is probable that the true concordance rate was 100% or at worst 97%, as one of the three showed a “partial” biochemical cure despite an LI of 3.5 and contralateral suppression. No conclusions were drawn — rightly so — for the 39 patients aged between 35 and 40 years; of the eight discordant subjects, one refused surgery, and follow-up was missing in five of the remaining seven. Worth noting is that in both groups women were the majority, particularly in the younger group (70%), which is very unusual for Japan, and in the younger group both plasma aldosterone concentration and estimated glomerular filtration rate were significantly higher — neither discussed.
The evidence base for the management of primary aldosteronism is thin, as shown by the half dozen confirmatory tests still in use; Mitsuhide Naruse, MD, PhD, as senior author deserves full credit for his efforts. If he is successful in rationalizing primary aldosteronism management, JPAS will break new ground for the rest of the world to examine, adapt and emulate.
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