Adjusting Drain Fluid Amylase for Drain Volume Does Not Improve Pancreatic Fistula Prediction

Abstract

Introduction: Drain fluid amylase (DFA) levels have been used to predict clinically relevant postoperative pancreatic fistula (CR-POPF) and guide postoperative drain management. Optimal DFA cutoff thresholds vary between studies, thereby prompting investigation of an alternative assessment technique. As DFA measurements could, in theory, be distorted by variations in ascites fluid production, we hypothesized that adjusting DFA for volume corrected drain fluid amylase (vDFA) would improve CR-POPF predictive models.

Methods: A single-institution retrospective cohort study of patients, who underwent pancreatoduodenectomies (PD) and distal pancreatectomies (DP) between 2013 and 2019, was performed. DFAs and vDFAs were measured on postoperative day (POD) 3. Clinicopathologic variables were compared between cohorts by univariable and multivariable analyses and Receiver operating characteristic (ROC) curves.

Results: Patients developing a CR-POPF were more likely to be male and have elevated DFA, vDFA, and body mass index (BMI). vDFA use did not contribute to a superior CR-POPF predictive model compared to DFA-a finding consistent on subanalysis of surgery type PD versus DP. In CR-POPF predictive models, DFA, vDFA, and male sex significantly improved CR-POPF predictive models when considering both surgery subtypes, while only DFA and vDFA significantly improved models when cohorts were segregated by surgery type.

Conclusions: Postoperative DFA remains a preferred method of predicting CR-POPF as the proposed vDFA assessment technique only adds complexity without increased discriminability.

Keywords: Abdominal drain; Amylase; Clinically relevant postoperative pancreatic fistula; Distal pancreatectomy; Pancreatic fistula; Pancreatoduodenectomy.