The Amount and Concentration of Drain Amylase Together Predict Postoperative Pancreatic Fistula after Gastric Cancer Surgery More Accurately than the Concentration Alone

Abstract

<b><i>Introduction:</i></b> The drain amylase concentration (dAmy-C) is a useful marker for predicting pancreatic fistula after gastric cancer surgery. However, dAmy-C might be reduced in cases of high drainage volume. Therefore, we hypothesized that we could accurately assess the amount of amylase leaked from the pancreas by multiplying dAmy-C by the daily drainage volume. In this study, we investigated the clinical utility of the amount of drain amylase (A-dAmy: concentration × volume) for predicting pancreatic fistula. We investigated the clinical utility of the combination of dAmy-C and A-dAmy for predicting pancreatic fistula. <b><i>Methods:</i></b> We investigated patients who underwent gastrectomy for gastric cancer at Yodogawa Christian Hospital between 2012 and 2020. The optimal cutoff levels of dAmy-C and A-dAmy on postoperative day 1 for predicting Clavien-Dindo (CD) grade II or higher pancreatic fistula was calculated using receiver operating characteristic (ROC) curves. We calculate the positive predictive value and negative predictive value for predicting pancreatic fistula using these cutoff levels. <b><i>Results:</i></b> A total of 448 patients were eligible for analysis. Twenty-two patients experienced CD grade II or higher pancreatic fistula. ROC curves identified 1,615 IU/L as the optimal cutoff level of dAmy-C, predicting pancreatic fistula. When the simple cutoff level of dAmy-C was 1,600 IU/L, the positive predictive value for was 22.8%, and the negative predictive value was 99.7%. ROC curves identified 177.52 IU as the optimal cutoff level of A-dAmy predicting pancreatic fistula. When the simple cutoff level of A-dAmy was 177 IU, the positive predictive value was 21.2%, and the negative predictive value was 99.7%. Using these two cutoff levels together, the positive predictive value was 34.4%, and the negative predictive value was 99.7%. <b><i>Conclusion:</i></b> A-dAmy could predict and exclude pancreatic fistula after gastrectomy as with dAmy-C. The combination of dAmy-C and A-dAmy predict pancreatic fistula more accurately than dAmy-C alone.