Dynamic Assessment of Drain Fluid Amylase Estimates the Risk of CR-POPF Following Pancreatoduodenectomy

Objective: To evaluate whether drain fluid amylase levels on day-1 (DFA1) and day-3 (DFA3) can reliably estimate the risk of clinically relevant-postoperative pancreatic fistula (CR-POPF) following pancreatoduodenectomy (PD) compared to either value alone or in combination with clinicopathologic variables. Background: CR-POPF is a major source of morbidity and mortality following PD. Current drain management algorithms are variable and are mostly dependent on DFA1, while the DFA3 is seldom utilized to guide clinical decision making. Methods: Between 2015-2020, patients who underwent PD at two high-volume pancreas centers and had intraoperative drain placement with measurement of DFA1 and DFA3 were retrospectively reviewed. Models to predict CR-POPF were constructed using DFA1, DFA3, fistula risk score (FRS) and other patient or treatment-related parameters. The fittest and more parsimonious model was used to construct a CR-POPF risk calculator. Results: Nine-hundred-twenty-three patients were included in the analysis. The FRS was high in 100(10.9%), intermediate in 524(57.3%), low in 211(23.1%) and negligible in 79(8.6%) patients. The overall rate of CR-POPF was 9.2%. Five logistic regression models were constructed using variables known to be implicated in CR-POPF. A model based solely on DFA1 and DFA3 with a cross-validated area under the curve of 0.846 was selected. A calculator using DFA1 and DFA3 was created based on this model to estimate the risk of CR-POPF. Conclusions: Risk of CR-POPF following pancreatoduodenectomy can be accurately estimated based on measurement of DFA1 and DFA3. Our CR-POPF kinetics calculator can facilitate postoperative risk stratification and guide drain management algorithms