Longitudinal Drain-Fluid Proteomics Reveals Procedure-Specific Signatures of Postoperative Leakage after Pancreatic and Colorectal Surgery

Anastomotic leakage is a serious complication after gastrointestinal surgery, with early detection limited by nonspecific clinical signs. The study included 33 pancreatic surgery patients with 201 drain-fluid samples and 34 colorectal surgery patients with 143 samples, followed up to 10 days postoperatively. In pancreatic surgery, enzymes AMY2A and PNLIP showed strong ability to distinguish leak from non-leak patients, while these markers were less reliable in colorectal surgery. Pancreatic leakage was characterized by early elevation (postoperative days 1-3) of enzymes followed by inflammatory and other proteins. Colorectal leakage was marked by decreased levels of wound-healing-related proteins around postoperative day 3. Novel candidate markers identified were PRSS2 and AZU1 for pancreatic surgery and FBLN1 and CDH5 for colorectal surgery.