To Use or Not to Use? Quantifying the Benefit of Microcatheter Use in Adrenal Vein Sampling

Adrenal vein sampling is a technically difficult procedure with reported sampling success rates as low as 41%. Routine microcatheter use has been suggested by some to improve sampling adequacy. This study is a single-institution retrospective review of adrenal vein sampling procedures performed from 2014 to 2021 to quantify sample selectivity and adequacy with and without the use of a microcatheter. Microcatheter sampling was performed in 43 (47%) of 92 cases on the right adrenal gland and 44 (48%) of 92 cases on the left adrenal gland. Mean selectivity index was significantly higher bilaterally with microcatheters (right, 36.8 vs 27.7; P = .05; left, 33.9 vs 19.9 left; P < .001). However, sampling adequacy rates did not significantly differ between microcatheter and 5-F sampling bilaterally (right, 91% vs 90%; P = .88; left, 96% vs 98%; P = .51). Adrenal hemorrhage occurred exclusively with right-sided microcatheter sampling (n = 6, 13%). In conclusion, although microcatheter sampling increases mean selectivity index, it does not change sampling adequacy rate and may increase the risk of right adrenal hemorrhage.