Anatomical Variations of the Right Adrenal Vein

Primary aldosteronism (PA) is currently considered the most frequent cause of secondary hypertension, with an estimated prevalence of ≈11% in hypertensive patients. Because a unilateral aldosterone-producing adenoma can be cured by adrenalectomy and bilateral hyperaldosteronism is usually treated medically, adrenal venous sampling (AVS) is necessary to provide a subtype diagnosis of PA. However, blood sampling from the right adrenal vein (RAV) remains difficult because of its small size and anatomical variations. Therefore, RAV mapping before AVS is required for technical success. Some past reports used contrast-enhanced multidetector computed tomography (MDCT) for visualization of the RAV. Several reports mentioned that the correct craniocaudal levels at the RAV orifice were identified in a majority of patients using MDCT; however, these studies did not note the angle of inflow of the RAV. A study by Matsuura et al reported the location of the RAV orifice on the horizontal plane and a 3-dimensional angle of inflow of the RAV using an 8-detector row computed tomography (CT). In this study, RAV anatomies were not compared using catheter venographic findings obtained during AVS, and the acquisition timing was not particularly designed to access the RAV. Although a common trunk with an accessory hepatic vein (AHV) has been considered the most frequent anatomical variant of the RAV that may decrease AVS success rates, its prevalence varied across previous studies, ranging from 8% to 24%. These studies may have had fewer subjects to determine the prevalence of anatomical variations. Moreover, the angle of inflow of the RAV in the common-trunk type has not been evaluated. In addition, even though the common trunk was not formed, the lesser distance between the RAV orifices and the AHV may cause sampling failure because of misidentification. Comprehensive anatomy of the RAV will help with successful AVS procedures achieved by appropriate catheter selection and manipulation. The purpose of this study was to provide a detailed description of anatomical variations of the RAV and to evaluate the concordance of RAV imaging between MDCT and catheter venography in a large population of patients with PA. Abstract—Adrenal venous sampling is the most reliable diagnostic procedure to determine surgical indications in primary aldosteronism. Because guidelines recommend multidetector computed tomography (CT) to evaluate the adrenal gland, some past reports used multidetector CT as a guide for adrenal venous sampling. However, the detailed anatomy of the right adrenal vein and its relationship with an accessory hepatic vein remains uncertain. The purpose of this study was to describe detailed anatomical variations of the right adrenal vein and to determine the concordance between CT and catheter venography in patients with primary aldosteronism. In total, 440 consecutive patients who underwent adrenal venous sampling were included. Four-phase dynamic CT was performed. Anatomical locations and variations of the right adrenal vein and its relationship with the accessory hepatic vein were compared with catheter venographic findings. Successful catheterization was achieved in 437 patients (99%). The right adrenal vein was visualized in the late arterial phase with CT in 420 patients (95%). The right adrenal vein formed a common trunk with the accessory hepatic vein in 87 patients (20%). CT identified the correct craniocaudal level of the orifice in 354 patients (84%). Anatomical variations, location, and angle of inflow of the right adrenal vein based on CT demonstrated high concordance with catheter venography. CT may provide useful information for preparation before adrenal venous sampling. (Hypertension. 2017;69:428-434. DOI: 10.1161/HYPERTENSIONAHA.116.08375.) • Online Data Supplement