Implications of increased serum amylase after pancreaticoduodenectomy: toward a better definition of clinically relevant postoperative acute pancreatitis

Background: Postoperative acute pancreatitis (POAP) can be a possible cause of postoperative pancreatic fistula (POPF). The present study aimed to evaluate the role of clinically-relevant POAP (CR-POAP), defined according to different cut-offs of postoperative amylase (AMS) values and C-reactive protein (CRP), in the development of clinically relevant POPF (CR-POPF) after pancreaticoduodenectomy (PD). Methods: Data from 610 patients who underwent PD (2015- 2018) were analyzed. Patients were divided according to the upper limit (100 U/l) and 3-fold the upper limit (300 U/l) of serum POD1 AMS. Univariate and multivariable analysis of possible predictors of CR-POPF were performed. Results: Overall, 360 patients (59%) had POD1 serum AMS <= 100 U/l, 142 patients (23%) had POD1 serum AMS >100 U/l and <= 300 U/l, and 108 patients (18%) had POD1 serum AMS >300 U/l. Patients with POD1 serum AMS >300 had a higher frequency of soft pancreatic texture, complications, main pancreatic duct diameter <= 3 mm, and CR-POPF. POD1 serum AMS >100 U/l associated to POD2 CRP >= 180 mg/l (OR: 4.3, p < 0.001) was an independent predictor of CR-POPF. Conclusion: These results confirm that CR-POAP, defined as POD1 serum AMS >100 U/l and POD2 CRP >= 180 mg/l, is associated with an increased risk of CR-POPF.