CRP in Drain Fluid as a Predictive Marker of Anastomotic Leak in Colorectal Surgery: A Systematic Review of the Literature

Background/Aim: Anastomotic leak (AL) remains one of the most troublesome complications in general surgery. The current review aimed to assess the level of C-reactive protein (CRP) in drainage fluid after entero-enteric, colonic, or colorectal anastomosis as a predictive biomarker for AL. Materials and Methods: Four medical databases (PUBMED-MEDLINE, Google Scholar, UpToDate, and Cochrane Library) were searched in January 2023 for prospective or retrospective studies on the role of acute-phase proteins in drainage fluid as a predictive biomarker of AL. Two independent researchers gathered and processed the data using MedCalc. The data were pooled and Student's t-test was used to compare the data between the AL and non-AL groups. Results: Overall, four studies were included in the current review, containing 753 patients in total, for whom various types of enteric and colonic anastomoses were constructed. Overall 79 (10.49%) of patients demonstrated AL and the mean CRP level (& PLUSMN;standard deviation) on postoperative day 3 was 167.7 & PLUSMN;77.13 mg/l. On the contrary, the non-AL group (674/753) had a statistically significantly lower mean CRP level at 83.76 & PLUSMN;20.32 mg/l. CRP values were not related to mortality. It was not possible to propose a CRP cut-off indicating an increased risk for AL as the data were insufficient. Conclusion: The CRP level in drainage fluid might be a valuable biomarker for predicting the possibility of AL in general surgery. However, further and larger-scale studies are needed to establish a CRP cut-off value and this variable would possibly be different for patients with different pathologies.