Diagnostic utility of data from adrenal venous sampling for primary aldosteronism despite failed cannulation of the right adrenal vein

Background. Adrenal venous sampling is an important lateralization study for primary aldosteronism, but inability to cannulate the right adrenal vein is not uncommon and interpreted as a failed study. We challenged this notion by examining whether data from incomplete left-sided adrenal venous sampling could accurately predict lateralization. Methods. Sixty-two adrenal venous sampling studies from 2007 to 2014 at 2 tertiary-care institutions were reviewed. For this analysis, data from the right adrenal vein were excluded. The study variable was the aldosterone:cortisol ratio of the left adrenal vein compared with the inferior vena cava (LAV/IVC). Scatterplot analysis identified high and low LAV/IVC cutoffs that predicted accurately unilateral disease in 1 institutional cohort and validated in the second cohort. Results. Thirty-six studies of adrenal venous sampling were evaluated at the first institution and divided into 3 diagnostic categories: unilateral-left (n = 14), unilateral-right (n = 12), and bilateral (n = 10). Cutoff values of the ratios of LAV/IVC of >= 5.5 and <= 0.5 accurately predicted left- and right-sided disease, respectively, and were validated in 26 studies from the second institution (100% PPV). The 5.5-0.5 criteria salvaged accuracy for predicting lateralization in 50% of cases. Conclusion. Even in the setting of failed cannulation of the right adrenal vein, the actual data from-the remaining adrenal venous sampling can predict lateralization accurately in many patients. A failed adrenal venous sampling study may be of greater predictive utility than believed traditionally.