A Practical Guide for Left Adrenal Vein Sampling in Patients with Left Renal Vein Variants.

Background: The presence of left renal vein (LRV) variants can increase the complexity of adrenal vein sampling (AVS), an already technically demanding procedure. While AVS literature often focuses on the right adrenal vein, an understanding of common LRV variants, their relationship with the left adrenal vein, and principles for successful catheterization can facilitate AVS. This guide provides practical, technical tips for AVS for duplicated (Du), circumaortic (Ca), and retroaortic (Ra) LRVs.

Methods: AVS cases were identified at a single institution (June 2009-March 2023) based on adrenophrenic trunk drainage relative to variant LRVs. Available cross-sectional imaging was reviewed to evaluate LRV anatomy pre-procedure. Twenty-seven cases (1 DuLRV, 13 CaLRVs, and 13 RaLRVs) were identified. Diagnostic AVS was confirmed by a threshold selectivity index. Literature on LRV anatomic variants was also reviewed.

Results: Based on the authors' experience and literature review, the following principles can guide AVS in the setting of LRV variants. In the presence of DuLRV or CaLRV, the left adrenal vein invariably drains into a normally positioned, pre-aortic LRV limb, so AVS can proceed as expected with a Simmons as the catheter of choice. In contrast, a LAV draining into a RaLRV may require a hockey stick-like catheter, or in rare cases a microcatheter, for selecting and sampling, due to the longer RaLRV course, which usually drains into the IVC more inferiorly and can be stenotic where the aorta crosses.

Conclusion: Knowing the presence and understanding the anatomy of LRV variants can facilitate an efficient AVS.