331 - Post-renal Transplant Collections – Which Patients Benefit from Lymphangiography?

Purpose: Post-renal transplant collections have a wide differential; urinomas, seromas, and lymphoceles frequently require IR drainage. Treating the underlying cause reduces duration of drainage. There is a paucity of data regarding what lymphocyte count defines a lymphocele and which patients benefit from lymphatic embolization. We hypothesize that high ( >80%) lymphocyte percentage predicts treatment success.

Materials and Methods: We performed a retrospective review of all patients with post-renal transplant collections from 12/2022 to 6/2025 who had a lymphangiogram. Patients undergoing lymphangiogram typically had at least 50% lymphocytes on fluid cell count. Lymphangiogram date, drain removal date, and fluid cell count lymphocyte percentage were recorded. Successful embolization was defined as any patient with drain removed at next follow up after lymphangiogram. Embolic agent was recorded (lipiodol only or lipiodol and glue). Continuous variables were evaluated with mean and standard deviation and compared with Wilcoxon rank-sum test. ROC curve analysis was conducted, and optimal cutoff was identified using Youden’s J statistic. 

Results: 18 patients had lymphangiograms during the study period. 9 patients had drains removed at subsequent follow up and 9 patients needed additional sclerotherapy. While glue was typically used only if an active leak was seen, it was not a statistically significant predictor of subsequent drain removal (p >0.05). Mean (SD) lymphocyte percentage was 88.56 (9.53)% in patients with and 82.22 (26.7)% in patients without successful embolization (p=0.044). ROC curve had an AUC of 0.47 with an optimal cutoff lymphocyte percentage of 79% with 89% sensitivity and 33% specificity. 

Conclusion: High fluid collection lymphocyte percentage has a high sensitivity and low specificity for successful intranodal embolization of lymphoceles in post-renal transplant patients. Lipiodol alone, even without identifying a leak, was successful in expediting drain removal in patients with high lymphocyte percentage. A cutoff lymphocyte percentage above 79% can potentially predict successful embolization.