MON-279 Precision in Adrenal Vein Sampling: Microcatheter Use in Left Adrenal Vein for Optimal Selective Index

Abstract Disclosure: M. Neff: None. J. Lin: None. N. Sharma: None. J. Sandhu: None. C. Issa: None. E. Garcia: None. K. Kozlowski: None. E. Hilborn: None. M. Jara: None. Z.C. Hannoush: None. A. Ayala: None. S. Rodgers: None. Z. Miller: None. Purpose: Adrenal vein sampling is a crucial diagnostic procedure for determining lateralization in primary aldosteronism and Cushing's to guide appropriate management, including targeted adrenalectomy. However, technical challenges in selective catheterization, particularly of the left adrenal vein (LAV) can impact diagnostic accuracy. This study aims to evaluate the effectiveness of using microcatheters during LAV sampling by comparing the Selectivity Index (SI) obtained with microcatheters versus standard catheter techniques. Materials and Methods: A retrospective study was conducted on patients who underwent LAV sampling, where SI measurements were recorded using both non-microcatheters and microcatheters. A total of 23 paired SI measurements were analyzed for each catheter type. Descriptive statistics were generated for both groups, and the wilcoxon signed rank test was employed to evaluate the statistical significance of differences in SI values between the two catheter types, with a significance threshold set at p<0.05. Results: The mean SI for non-microcatheters was 14.70, median 12.37 (IQR 7.30-19.9), while the mean SI for microcatheters was significantly higher at 20.53, median 19.45 (IQR 9.71-31.82). The wilcoxon signed rank test indicated a statistically significant improvement in SI with the use of microcatheters (Z = 2.79, r=0.49, p = 0.005). The largest difference in SI between the two methods had a mean value of 11.22, median 14.11 (IQR 3.17-23.70). Conclusions: The use of microcatheters in LAV sampling significantly improves the SI compared to non-microcatheters. This enhancement indicates that microcatheters offer greater reliability in sampling, potentially leading to more accurate diagnoses and improved clinical outcomes for patients undergoing evaluation for adrenal disorders. Presentation: Monday, July 14, 2025