Drain fluid amylase as a sensitive biomarker for the early detection of anastomotic leakage in ileal pouch surgery

Aim We studied the levels of amylase in drain fluid to investigate its utility as a biomarker of anastomotic leak in ileal pouch patients who did not have a covering loop ileostomy. The luminal contents of the small intestine are high in amylase. Ileal J pouches are formed for restoration of continuity in patients with ulcerative colitis after removal of the colon and rectum. A drain is placed alongside the ileal pouch in the pelvis. Method This study is a retrospective analysis of prospectively collected daily drain fluid amylase levels in consecutive patients undergoing restorative proctectomy and ileal J pouch anal anastomosis, without a covering loop ileostomy, between November 2016 and April 2018. Results Thirteen patients underwent surgery without a covering loop ileostomy. Two patients suffered an anastomotic leak and were returned to theatre, one on day 5 and the other on day 6 postoperatively. The mean daily drain fluid amylase level in those who did not leak was between 25 and 46 U/l with a range of 22-139 U/l for all samples collected. In the two patients who suffered a clinical leak the drain fluid amylase level rose to 22 432 and 10 212 U/l on the day of clinical leak diagnosis. The mean rectal tube (intraluminal) amylase level was 63 097 U/l as measured on day 1 postoperatively. Conclusion In this small cohort of patients, the measurement of drain fluid amylase is a highly sensitive biomarker of clinical anastomotic leak.