Evaluation and Recalibration of Risk-Stratified Pancreatoduodenectomy Drain Fluid Amylase Removal Criteria

Background: Risk-stratified drain fluid amylase cutoff values for postoperative day 1 (POD1) (DFA1) and POD3 (DFA3) can guide early drain removal after pancreatoduodenectomy (PD). The aim of this study was to evaluate and recalibrate cutoff values instituted in Feb 2019 using a prospective sequential cohort. Methods: We performed a single-institution prospective cohort study of consecutive patients who underwent pancreatoduodenectomy following implementation of institution-specific DFA cutoffs in February 2019 through April 2022. DFA values, drain removal, and clinically relevant postoperative pancreatic fistulas (CR-POPF) were analyzed. Receiver operating characteristic (ROC) curve analysis determined optimal cutoff values. Results: In total, 267 patients, 173 (65%) low-risk and 94 (35%) high-risk, underwent 228 (85%) open and 39 (15%) robotic pancreatoduodenectomies. Seven (4%) low-risk patients and 21 (22%) high-risk patients developed CR-POPF. Drains were removed in 147 (55%) patients before/on POD3, with 1 (0.7%) CR-POPF. In low-risk patients, CR-POPF was excluded with 100% sensitivity if DFA1 < 286 (area under curve, AUC = 0.893, p = 0.001) or DFA3 < 97 (AUC = 0.856, p = 0.002). DFA1 < 137 (AUC = 0.786, p < 0.001) or DFA3 < 56 (AUC = 0.819, p < 0.001) were 100% sensitive in high-risk patients. Previously established DFA1 cutoffs of 100 (low-risk) and < 26 (high-risk) were 100% sensitive, while DFA3 cutoffs of 300 (low-risk) and 200 (high-risk) had 57% and 91% sensitivity. Conclusions: Within a learning health system, we recalibrated post-PD drain removal thresholds to DFA1 ≤ 300 and DFA3 ≤ 100 for low-risk and DFA1 ≤ 100 and DFA3 ≤ 50 for high-risk patients. This methodology is generalizable to other centers for developing institution-specific criteria to optimize safe early drain removal.