Difficulty factors of adrenal venous sampling based on patient characteristics and imaging findings

Background Primary aldosteronism is one of the most common causes of secondary hypertension. Unilateral primary aldosteronism can be treated with adrenalectomy; therefore, determining laterality is essential, for which adrenal venous sampling is considered the gold standard. However, as catheter insertion and sampling at an appropriate venous point is occasionally difficult, it is a time-consuming procedure. Purpose To evaluate the patient characteristics and imaging findings that influence the adrenal venous sampling procedure. Material and Methods A total of 69 patients who underwent adrenal venous sampling between January 2013 and December 2017 were retrospectively analyzed. The procedure was considered difficult if the duration was > 142 min (mean +/- standard deviation [SD] of procedure time in this study) and/or proper sampling failed. Anatomical factors such as belly diameter, presence of adrenal nodules, diameter of the right adrenal vein and inferior vena cava, ratio of the diameters of the right adrenal vein to diameter of the inferior vena cava, vertical direction of the right adrenal vein, and vertebral level of the right adrenal vein were evaluated as predictive factors on computed tomography. Results Fifteen patients (21.7%) were considered difficult cases. The factors associated with difficulty were the long transverse diameter of the belly (P = 0.004) and high vertebral level of the right adrenal vein (P = 0.032). No statistical differences were observed in any other factors. Conclusion The long transverse diameter of the belly and high vertebral level of the right adrenal vein may prevent completion of the adrenal venous sampling procedure.