Neutrophil-to-lymphocyte ratio vs C-reactive protein as early predictors of anastomotic leakage after colorectal surgery: A retrospective cohort study

Drainage fluid LDH and neutrophil to lymphocyte ratio as biomarkers for early detecting anastomotic leakage in patients undergoing colorectal surgery

OBJECTIVES

In this study, we investigated the role of several circulating and drainage fluid biomarkers for detecting postoperative complications (PCs) and anastomotic leakage (AL) in patients undergoing colorectal surgery.

METHODS

All consecutive patients undergoing colorectal surgery between June 2018 and April 2020 were prospectively considered. On postoperative days (POD) 1, 3, and 5, we measured lactate dehydrogenase (LDH) in drainage fluid, C-reactive protein (CRP) in serum and drainage fluid, and neutrophil to lymphocyte ratio (NLR).

RESULTS

We enrolled 187 patients. POD1 patients with AL had higher serum CRP levels, while on POD3 and on POD5 higher NLR and serum CRP. LDH and CRP in drainage fluid were also significantly higher at both time points. The area under the curves (AUCs) of serum and drainage fluid CRP were 0.752 (0.629-0.875) and 0.752 (0.565-0.939), respectively. The best cut-off for serum and drainage fluid CRP was 185.23 and 76 mg/dL, respectively. The AUC of NLR on POD3 was 0.762 (0.662-0.882) with a sensitivity and specificity of 84 and 63 %, respectively, at a cut-off of 6,6. Finally, drainage fluid LDH showed the best diagnostic performance for AL, with an AUC, sensitivity, and specificity of 0.921 (0.849-0.993), 82 %, and 90 % at a cut-off of 2,186 U/L. Trends in serum parameters between patients with or without PCs or AL were also evaluated. Interestingly, we found that NLR decreased faster in patients without PCs than in patients with PCs and patients with AL.

CONCLUSIONS

Drainage fluid LDH and NLR could be promising biomarkers of PCs and AL.

Systematic review of the significance of neutrophil to lymphocyte ratio in anastomotic leak after gastrointestinal surgeries

INTRODUCTION

The inflammatory response is thought to be a critical initiator of epigenetic alterations. The neutrophil to lymphocyte ratio (NLR), a biomarker of inflammation, is computed by dividing the number of neutrophils by the number of lymphocytes. The primary goal of this systematic review and meta-analysis was to evaluate the pre-operative NLR of gastrointestinal surgery patients who had an anastomotic leak (AL) in comparison to those who did not AL.

METHODS

We performed a comprehensive search for relevant papers published before May 4, 2022, using PubMed, Scopus, and Web of Science. Standardized mean difference (SMD) with a 95% confidence interval (CI) was pooled in meta-analysis to yield a summary estimate. We utilized the random-effects model to create pooled effects since we discovered a substantial heterogeneity level. For evaluating quality, the Newcastle-Ottawa scale (NOS) was implemented.

RESULTS

The research comprised 12 studies with a total of 2940 individuals who had GI operations, 353 of whom went on to develop AL. We discovered that patients who had GI surgeries and acquired AL had significantly higher NLR levels than those who did not (random-effects model: SMD = 0.75, 95% CI = 0.11-1.38, p = 0.02). Patients with AL showed significantly higher NLR levels than control group in retrospective studies (SMD = 0.93, 95% CI = 0.20-1.66, p=0.01) but not in prospective studies (SMD = - 0.11, 95% CI = - 0.65-0.43, p = 0.69), according to the subgroup analysis based on research design. Subgroup analysis based on ethnicity yielded that white patients with AL exhibited significantly higher NLR values than the control group (SMD = 1.35, 95% CI = 0.01-2.68, p = 0.04) but this result was not applied to East Asian patients (SMD = 0.14, 95% CI = -0.13-0.41, p = 0.29).

CONCLUSION

Our research suggests a potential association between preoperative NLR and postoperative AL. However, it is essential to acknowledge the variability in the findings, with significantly higher NLR levels observed in retrospective studies and among white patients, but not consistently replicated in prospective studies and among East Asian patients. Further investigations with larger and more diverse cohorts are warranted to validate these findings and explore potential factors contributing to the observed discrepancies.

C-reactive Protein and Procalcitonin Levels to Predict Anastomotic Leak After Colorectal Surgery: Systematic Review and Meta-analysis

BACKGROUND

Anastomotic leak (AL) is a feared complication after colorectal surgery. Prompt diagnosis and treatment are crucial. C-reactive protein (CRP) and procalcitonin (PCT) have been proposed as early AL indicators. The aim of this systematic review was to evaluate the CRP and CPT predictive values for early AL diagnosis after colorectal surgery.

METHODS

Systematic literature search to identify studies evaluating the diagnostic accuracy of postoperative CRP and CPT for AL. A Bayesian meta-analysis was carried out using a random-effects model and pooled predictive parameters to determine postoperative CRP and PCT cut-off values at different postoperative days (POD).

RESULTS

Twenty-five studies (11,144 patients) were included. The pooled prevalence of AL was 8% (95 CI 7-9%), and the median time to diagnosis was 6.9 days (range 3-10). The derived POD3, POD4 and POD5 CRP cut-off were 15.9 mg/dl, 11.4 mg/dl and 10.9 mg/dl respectively. The diagnostic accuracy was comparable with a pooled area under the curve (AUC) of 0.80 (95% CIs 0.23-0.85), 0.84 (95% CIs 0.18-0.86) and 0.84 (95% CIs 0.18-0.89) respectively. Negative likelihood ratios (LR-) showed moderate evidence to rule out AL on POD 3 (LR- 0.29), POD4 (LR- 0.24) and POD5 (LR- 0.26). The derived POD3 and POD5 CPT cut-off were 0.75 ng/ml (AUC = 0.84) and 0.9 ng/ml (AUC = 0.92) respectively. The pooled POD5 negative LR (-0.18) showed moderate evidence to rule out AL.

CONCLUSIONS

In the setting of colorectal surgery, CRP and CPT serum concentrations lower than the derived cut-offs on POD3-POD5, may be useful to rule out AL thus possibly identifying patients at low risk for AL development.

Neutrophil-to-Lymphocyte Ratio as an Early Predictor of Symptomatic Anastomotic Leakage in Patients after Rectal Cancer Surgery: A Propensity Score-Matched Analysis

Background: This study aimed to explore the role of postoperative neutrophil-to-lymphocyte ratio in predicting symptomatic anastomotic leakage in patients who underwent laparoscopic low anterior resection for rectal cancer. Methods: In this retrospective cohort study, we analyzed data of patients who underwent laparoscopic low anterior resection from May 2009 to May 2019. A receiver operating characteristic curve analysis was performed to evaluate the cut-off values with the best predictive efficacy of a symptomatic anastomotic leakage. In addition, a propensity score-matched analysis was performed by considering all covariate variables, and 61 patients with or without symptomatic anastomotic leakage were included in the analysis. Results: The present study included 306 patients; of these, 17 (5.56%) developed symptomatic anastomotic leakage after surgery. On postoperative day 5, compared with patients without symptomatic anastomotic leakage, those with leakage had significantly higher neutrophil-to-lymphocyte levels. Notably, a neutrophil-to-lymphocyte cut-off score of 6.54 indicated the best area under the curve of 0.818 (95% confidence interval: 0.697−0.940, p < 0.001) in predicting symptomatic anastomotic leakage, with a sensitivity and specificity of 76.5% and 79.4%, respectively. Conclusions: Although evidence for the predictive role of neutrophil-to-lymphocyte ratio is accumulating, it remains inconclusive. In addition, neutrophil-to-lymphocyte levels should be considered a predictive biomarker for symptomatic anastomotic leakage; however, it can more accurately be viewed as an adjunct that helps increase the clinical suspicion of emerging symptomatic anastomotic leakage.

The Significance of Blood and Peritoneal Fluid Biochemical Markers in Identifying Early Anastomotic Leak following Colorectal Resection-Findings from a Single-Center Study

Background and Objectives: The aim of our study was to evaluate the value of leukocyte, C reactive protein (CRP), procalcitonin, lactate, and carcinoembryonic antigen (CEA) in blood and peritoneal fluid in early recognition of anastomotic leak (AL) after colorectal resections. Materials and Methods: Our pilot prospective cohort study was conducted at the abdominal surgery department at University Medical Center Ljubljana. A total of 43 patients who underwent open or laparoscopic colorectal resection because of benign or malignant etiology were enrolled. All of the patients had primary anastomosis without stoma formation. Results: Three patients in our patient group developed AL (7%). We found a statistically significant elevation of serum lactate levels in patients that developed AL compared to those who did not but noted no statistically relevant difference in the blood or peritoneal fluid levels of other biochemical markers. Conclusions: Elevated lactate levels may be considered a promising biomarker for the early diagnosis of AL, but more research on bigger patient groups is warranted.

Implantation of an Impedance Sensor for Early Detection of Gastrointestinal Anastomotic Leaks

INTRODUCTION

Accurate early diagnosis of a gastrointestinal anastomotic leak remains a challenge. When an anastomotic leak develops, the electrical properties of the tissue undergoing inflammatory processes change, resulting from the extravasation of inflammatory fluid and cellular infiltration. The method described here intends to provide a novel early anastomotic leak warning system based upon measurable changes in tissue impedance nearby an acute inflammatory process.

METHODS

A biodegradable Mg-alloy was compared with a nonabsorbable stainless steel (STS) electrode connected to a wireless recording system for impedance measurement. In vitro measurements were made in physiological solutions and small animal (eight mice) and large animal (eight pigs) models with an anastomotic leak simulated by an open colotomy. Measurements were made at 10 mm intervals from the open colon at baseline and up to 120 min comparing these with a sutured colonic wound and normal tissue.

RESULTS

In-vitro biodegradable magnesium electrode impedance evaluation showed good sensitivity to different media due to its environmental corrosion properties. The impedance of an acidic environment (1.06 ± 0.02 kΩ for citric acid) was twice that of phosphate-buffered saline (PBS) (0.64 ± 0.008 kΩ) with a distinction between Normal Saline (0.42 ± 0.013 kΩ) and PBS (0.64 ± 0.008 kΩ). This was in contrast to the performance characteristics of the control STS electrodes, where impedance in an acidic environment was lower than saline or PBS (citric acid:0.76 ± 0.01 kΩ versus PBS: 1.32 ± 0.014 kΩ). In a mouse model simulating an anastomotic leak, there was a significant increase in impedance after 120 min when compared with controls (99.7% increase versus 9.6% increase, respectively; P < 0.02). This effect was confirmed in a pig model when relative impedance measurements of the leak and control groups were compared (1.86 ± 0.46 versus 1.07 ± 0.02, respectively; P < 0.027).

CONCLUSIONS

Electrophysiological measurement shows diagnostic sensitivity for a gastrointestinal leak with potential clinical utility in the postoperative detection of early intra-abdominal sepsis. Further investigation of biodegradable tissue sensors capable of monitoring an early anastomotic leak is required.