SRS254 - Anastomotic leak prediction after colorectal anastomosis (ALPACA) study: Preliminary results of clinical variables, cell counts and cell phenotypes

Introduction Anastomotic leaks (AL) are devastating complications to patients, family and surgeons. Early diagnosis could allow interventions to prevent the septic sequalae that follows. Our aim is to identify systemic and local (peritoneal) markers that can predict ALs on day 1 or day 2 post-operatively. Methods Patients undergoing left sided resectional or restorative surgery for any pathology were recruited from a single tertiary centre from October 2024 to present. A peritoneal drain was placed near the anastomosis during surgery. Drain fluid and peripheral blood was collected on day 1 and day 2 post-operatively. Results 79 patients were recruited to the ALPACA study as of August 2025. 14 patients were withdrawn due to operation type, or no drain being placed intraoperatively. Of the 65 patients, 10 (12.7%) patients had an AL. Length of stay was significantly higher in the AL cohort (P = 0.002). The AL cohort had a higher serum CRP on day 2 (P = 0.007). Total cell count (TCC) per ml of drain fluid was available for 61 patients. The TCC per ml of drain fluid was significantly higher in AL patients on day 2 (P = 0.002) with good diagnostic accuracy (ROC = 0.82). Although not significant, AL patients showed a greater day 1–2 post-operative rise in monocyte proportion among live cells than non-AL patients. Conclusions Our preliminary findings show clinical variables in this cohort reflect published data. Cell phenotypes were similar between the two cohorts. Drain fluid TCC was significantly higher on day 2 post-operatively with promising diagnostic accuracy.