Localization of Aldosterone-Producing Adenoma: Venous Sampling in Primary Aldosteronism

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Adrenal venous sampling of blood was performed for nine patients withaldosterone-producing adenoma (APA). Measurement of adrenal venous aldosteroneis useful for localization of APA but difficult, because catheterization ofthe right adrenal vein is not easy, and the blood is diluted by nonadrenal flow. To solve these problems, levels of aldosterone (A; ng/dl) and cortisol (C;μg/dl) were measured in samples from the left adrenal vein (LAV) andtheinferior vena cava (IV C), and the LAV A/C and (LAV A/C)/(IVC A/C) ratios were calculated. These ratios were also obtained for 16 patients withessential hypertension.
The adenoma could be localized in three of the nine cases by the measurementof aldosterone alone, but the use of a LAV A/C ratio greater than 5×10^-3 and a (LAV A/C)/(IVA A/C) ratio less than 1.0 as criteria separated the patients intothose with a left APA, right APA, or esseential hypertension. Consequently, adrenal venous sampling and the calculation of these ratios enables preoperativelocalization of APA with more accuracy, especially when the tumor is small or the result of CT and adrenal scintigraphy is not consistent.