Context The number of centers with established adrenal venous sampling (AVS) programs for the subtype diagnosis of primary aldosteronism (PA) is limited. Objective Aim was to develop an algorithm for AVS based on subtype prediction by computed tomography (CT) and serum potassium. Design A multi-institutional retrospective cohort study in Japan. Patients A total of 1591 patients with PA were classified into four groups according to CT findings and potassium status. Subtype diagnosis of PA was determined by AVS. Main Outcome Measure Prediction value of the combination of CT findings and potassium status for subtype diagnosis. Results The percentages of unilateral hyperaldosteronism on AVS were higher in patients with unilateral disease on CT than those with bilateral normal results on CT (50.8% vs 14.6%, P < 0.01), and these percentages were higher in those with hypokalemia than those with normokalemia (58.4% vs 11.5%, P < 0.01). The prevalence and odds ratio for unilateral hyperaldosteronism on AVS were as follows: bilateral normal on CT with normokalemia, 6.2% (reference); unilateral disease on CT with normokalemia, 23.8% and 4.8 [95% confidence interval (CI), 3.1 to 7.2]; bilateral normal on CT with hypokalemia, 38.1% and 9.4 (95% CI, 6.2 to 14.1), and unilateral disease on CT with hypokalemia, 70.6% and 36.4 (95% CI, 24.7 to 53.5). Conclusions Patients with PA with bilateral normal results on CT and normokalemia likely have a low prior probability of a lateralized form of AVS and could be treated medically, whereas those with unilateral disease on CT and hypokalemia have a high probability of a lateralized form of AVS.
1 May 2012 in The Journal of Clinical Endocrinology & Metabolism
Although confirmatory testing to verify aldosterone excess is a key step in the diagnosis of primary aldosteronism (PA), there is no consensus as to whether it is always needed and which of the tests need to be performed. The objective of this study was to investigate the diagnostic significance of confirmatory tests in PA. In group A, 120 hypertensive patients who had positive case detection using the aldosterone to renin ratio (ARR) were subjected to at least one confirmatory test: the captopril challenge test (CCT), furosemide upright test (FUT), or saline infusion test (SIT). Among group A, 57 patients underwent all three confirmatory tests (group B), and 57 patients were differentiated as having either unilateral or bilateral PA based upon adrenal venous sampling, adrenal scintigraphy, and/or adrenal surgery (group C). The percentages of patients with positive CCT and FUT were 86 and 87% in group A, 88 and 88% in group B, and 96 and 94% in group C, respectively. The percentage of patients with positive SIT results was lower than that with other tests (P < 0.01). The percentage of patients with positive results for the three tests was higher in patients with baseline ARR of at least 1000 or plasma aldosterone concentration (PAC) of at least 250 pg/ml than in those with lower ARR or PAC in all three groups. Most patients with positive case detection also had positive results on the CCT and FUT, especially when ARR was at least 1000 or PAC was at least 250 pg/ml under renin suppresion. Confirmatory testing for PA may not be needed in all patients with positive case detection.