Identifying predictors of lymphatic leak after nephrectomy using American College of Surgeons-National Surgical Quality Improvement Program Targeted Data.

e16545 Background: Chylous ascites is a rare complication of nephrectomy with a reported incidence of up to 5.9%, caused by the disruption of lymphatic vessels in the retroperitoneum. Data from single institution retrospective reviews identify left-sided surgery, higher body mass index (BMI), and radical/donor nephrectomy as potential risk factors but are limited by small population size. We sought to identify predictors of lymphatic leak following nephrectomy using the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) Nephrectomy-Targeted database. Methods: Using the database from 2019 to 2022, we identified adult ( > 18 years old) patients who underwent nephrectomy. Patients were then dichotomized based on whether they developed lymph leak. We performed logistic regression to determine the association between baseline and perioperative covariates with development of lymph leak. Similarly, we evaluated the association between development of lymph leak and 30-day postoperative complications. Results: Our results yielded a total of 29,299 nephrectomies performed, of which 586 (2.0%) were documented to have a lymph leak. Open approach, left laterality, N1 or M1 staging, major visceral resection, lymph node sampling, unplanned conversion to open, nephrology related chemotherapy, prior pelvic surgery, higher preoperative creatinine, lower preoperative hemoglobin, lower preoperative albumin, ASA class, history of recent weight loss, steroid use, bleeding disorder, dialysis, disseminated cancer, or congestive heart failure. were associated with an increased likelihood of lymph leak. In our analysis, age, gender, ethnicity, BMI, history of smoking or diabetes were not statistically significantly associated with increased lymph leak. In the postoperative setting, there was association between development of lymph leak and myocardial infarction, cardiac arrest, postoperative ileus, postoperative bleeding, urinary tract infection, surgical site infection, clostridium difficile colitis, sepsis, pneumonia, venous thromboembolic event, renal insufficiency, unplanned reoperation, longer hospital stay, and readmissions. Conclusions: Chylous ascites is associated with worse postoperative outcomes. To our knowledge, this is the largest contemporary population-based analysis of risk factors for lymph leak following nephrectomy; our findings can be used to guide surgeons in determining which patients should be counseled to adhere to a postoperative prophylactic low fat diet and monitored closely for chylous ascites.