Quantification of fluorescence angiography for visceral perfusion assessment: measuring agreement between two software algorithms.

BACKGROUND: Indocyanine green fluorescence angiography (ICG-FA) may reduce perfusion-related complications of gastrointestinal anastomosis. Software implementations for quantifying ICG-FA are emerging to overcome a subjective interpretation of the technology. Comparison between quantification algorithms is needed to judge its external validity. This study aimed to measure the agreement for visceral perfusion assessment between two independently developed quantification software implementations. METHODS: This retrospective cohort analysis included standardized ICG-FA video recordings of patients who underwent esophagectomy with gastric conduit reconstruction between August 2020 until February 2022. Recordings were analyzed by two quantification software implementations: AMS and CPH. The quantitative parameter used to measure visceral perfusion was the normalized maximum slope derived from fluorescence time curves. The agreement between AMS and CPH was evaluated in a Bland-Altman analysis. The relation between the intraoperative measurement of perfusion and the incidence of anastomotic leakage was determined for both software implementations. RESULTS: Seventy pre-anastomosis ICG-FA recordings were included in the study. The Bland-Altman analysis indicated a mean relative difference of + 58.2% in the measurement of the normalized maximum slope when comparing the AMS software to CPH. The agreement between AMS and CPH deteriorated as the magnitude of the measured values increased, revealing a proportional (linear) bias (R2 = 0.512, p < 0.001). Neither the AMS nor the CPH measurements of the normalized maximum slope held a significant relationship with the occurrence of anastomotic leakage (median of 0.081 versus 0.074, p = 0.32 and 0.041 vs 0.042, p = 0.51, respectively). CONCLUSION: This is the first study to demonstrate technical differences in software implementations that can lead to discrepancies in ICG-FA quantification in human clinical cases. The possible variation among software-based quantification methods should be considered when interpreting studies that report quantitative ICG-FA parameters and derived thresholds, as there may be a limited external validity.

Early predictive factors and risk assessment for anastomotic leakage in patients undergoing low anterior resection for rectal cancer.

OBJECTIVE: Anastomotic leakage is a complication that creates significant concern in terms of postoperative morbidity and mortality after colorectal surgery. This study aimed to identify variables for detecting anastomotic leakage in those who had open, laparoscopic, or robotic low anterior resection for cancer and to explore their relationships. PATIENTS AND METHODS: A total of 283 patients who were diagnosed with rectal cancer and underwent low anterior resection were divided into two groups: those with and without anastomotic leakage. Demographic and clinical data were analyzed. Anastomotic leakage was detected in 23 of 283 patients who underwent low anterior resection. RESULTS: The postoperative analysis of the biochemical data of the patients showed statistically significant differences between the two groups in terms of C-reactive protein (Crp), albumin, lymphocytes, leukocytes, neutrophils, and their ratio. The performance of these parameters in predicting anastomotic leakage was statistically analyzed in the patient group with anastomotic leakage, and nomogram results were acquired. Immune system components and biomarkers were statistically tested, and nomogram results were obtained in rectal cancer patients. CONCLUSIONS: These parameters can be used together as a potential marker in anastomotic leakage. Further development of these variables has the potential to facilitate the timely detection and treatment of anastomotic leakage.

'4-Check' protocol for intraoperative anastomotic assessment during transanal total mesorectal excision: retrospective cohort study.

BACKGROUND: Anastomotic leakage is a major complication following rectal cancer surgery. The primary aim of this study was to investigate the efficacy of a protocol based on a quadruple intraoperative anastomotic assessment (4-Check) during transanal total mesorectal excision (TaTME). METHODS: Patients who underwent TaTME for rectal cancer with primary anastomosis were reviewed and divided into two groups: before (pre-4-Check: April 2015 - April 2019) and after the implementation of the 4-Check protocol (May 2019 - May 2022). This protocol consisted of a multimodal anastomotic integrity assessment, including indocyanine green-evaluation of colonic stump and intraluminal anastomosis perfusion, a reverse air leak test and anastomotic doughnuts assessment. The primary outcome was incidence of clinical and/or radiological anastomotic leakage. The secondary outcome included intraoperative anastomosis defects and repairs and 30-day complication rate. Propensity score matching and multivariable analyses were performed. RESULTS: Of 186 patients, 160 were selected: 86 patients in the pre-4-Check and 74 in the 4-Check group. After propensity score matching, there was no difference in postoperative anastomotic leakage (pre-4-Check versus 4-Check: 11.1 per cent versus 7.4 per cent; P = 0.50). However, in the 4-Check group, the intraoperative detection of defects and repairs was significantly increased (P = 0.03), and the number of complications was reduced (pre-4-Check versus 4-Check: 33.3 per cent versus 9.3 per cent, P = 0.004). Multivariable analyses confirmed that the use of the 4-Check protocol, the detection of anastomotic defects and increased albumin levels were associated with a reduced number of complications. CONCLUSION: The 4-Check protocol allowed the intraoperative detection and repair of anastomotic defects. Anastomotic leakage rates were not reduced; however, 30-day complication rates were lower after implementation of this protocol.

Preoperative assessment of blood supply and its role in predicting anastomotic leak.

BACKGROUND: Anastomosis leak is one of the significant postoperative complications after colorectal surgery. The aim of this systematic review was to synthesize the evidence relative to the preoperative assessment of the colon and rectum blood supply and to investigate its role in predicting anastomosis leak. METHOD: This systematic review was conducted according to the recommendations of the Cochrane Handbook for Reviews of Interventions and reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, Embase, and the Cochrane Library were searched to identify eligible studies. The main outcome variable was the preoperative assessment of patterns of blood supply to the colon and the impact of these patterns on anastomosis leak. The quality of bias control in the studies was assessed using the Newcastle-Ottawa Scale. Due to the heterogeneous nature of the included studies, no meta-analysis was conducted. RESULTS: Fourteen studies were included. The study covered a period from 1978 to 2021. A significant degree of variation in the arterial and/or venous supply of the colon and rectum might influence anastomosis leak rates. Calcification in great blood vessels can be assessed with a preoperative computed tomography scan, which may predict anastomosis leak rates. This is supported by many experimental studies that showed increased rates of anastomosis leak after preoperative ischemia, but the extent of this impact is not well established. CONCLUSION: Preoperative assessment of blood supply to the colon and rectum might help in planning the surgical intervention to reduce anastomosis leak rates. Calcium scoring of major arteries might predict anastomosis leak and thus play a crucial role in intraoperative decision-making.

Intraluminal Anastomotic Assessment Using Indocyanine Green Near-Infrared Imaging for Left-Sided Colonic and Rectal Resections: a Systematic Review.

BACKGROUND: Indocyanine green fluorescence angiography (ICG-FA) has been used in colorectal surgery to assess anastomotic perfusion and reduce the risks of anastomotic leaks. The main objective of this paper is to review the data on the transanal application of ICG-FA for the intraluminal assessment of colorectal anastomosis. METHODS: A literature search was conducted for articles published between 2011 and 2021 using PubMed and Cochrane databases, related to the application of ICG for the intraluminal assessment of colorectal anastomosis. Original scientific manuscripts, review articles, meta-analyses, and case reports were considered eligible. RESULTS: A total of 305 studies have been identified. After abstract screening for duplicates, 285 articles remained. Of those, 271 were not related to the topic of interest, 4 were written in a language other than English, and 4 had incomplete data. Six articles remained for the final analysis. The intraluminal assessment of colorectal anastomosis with ICG-FA is feasible, safe, and may reduce the incidence of leaks. CONCLUSION: The intraluminal assessment of anastomotic perfusion via ICG-FA may be a promising novel application of ICG technology. More data is needed to support this application further to reduce leak rates after colorectal surgery, and future randomized clinical trials are awaited.

Multisensor perfusion assessment cohort study: Preliminary evidence toward a standardized assessment of indocyanine green fluorescence in colorectal surgery.

BACKGROUND: Traditional methods of assessing colonic perfusion are based on the surgeon's visual inspection of tissue. Fluorescence angiography provides qualitative information, but there remains disagreement on how the observed signal should be interpreted. It is unclear whether fluorescence correlates with physiological properties of the tissue, such as tissue oxygen saturation. The aim of this study was to correlate fluorescence intensity and colonic tissue oxygen saturation. METHODS: Prospective cohort study performed in a single academic tertiary referral center. Patients undergoing colorectal surgery who required an anastomosis underwent dual-modality perfusion assessment of a segment of bowel before transection and creation of the anastomosis, using near-infrared and multispectral imaging. Perfusion was assessed using maximal fluorescence intensity measurement during fluorescence angiography, and its correlation with tissue oxygen saturation was calculated. RESULTS: In total, 18 patients were included. Maximal fluorescence intensity occurred at a mean of 101 seconds after indocyanine green injection. The correlation coefficient was 0.73 (95% confidence interval of 0.65-0.79) with P < .0001, showing a statistically significant strong positive correlation between normalized fluorescence intensity and tissue oxygen saturation. The use of time averaging improved the correlation coefficient to 0.78. CONCLUSION: Fluorescence intensity is a potential surrogate for tissue oxygenation. This is expected to lead to improved decision making when transecting the bowel and, consequently, a reduction in anastomotic leak rates. A larger, phase II study is needed to confirm this result and form the basis of computational algorithms to infer biological or physiological information from the fluorescence imaging data.

Early endoscopic assessment after esophagectomy can predict anastomotic complications: a novel scoring system.

BACKGROUND: Anastomotic leakage after esophagectomy is a serious and demanding complication. Early detection and treatment can probably prevent clinical deterioration of the patient. We have used early endoscopic assessment and a novel endoscopy score to predict anastomotic complications. METHODS: 57 patients planned for Ivor Lewis esophagectomy were included. Endoscopy videos were recorded and biopsies were taken from the gastric conduit on day 7 or 8 after esophagectomy. A scoring system based on the endoscopic appearance, the combined endoscopy score (0-6), was developed. Scoring of the videos was done blinded. Patient outcome with regards to anastomotic complications was registered on postoperative day 30 in accordance with the ECCG definitions and compared to histopathology assessment and the combined endoscopy score retrospectively. RESULTS: The rate of anastomotic defect (necrosis and leakage, ECCG definitions) was 19%. 7 out of 8 patients with a combined endoscopy score of ≥ 4 developed anastomotic defects. The combined endoscopy score was the only predictor for anastomotic complications. CONCLUSION: Prediction of anastomotic complications enables early detection and treatment which often limits the clinical extent of the complication. Early postoperative endoscopy is safe and a relatively simple procedure. The combined endoscopy score is an accurate tool to predict anastomotic complications.

Serial assessment of inflammatory parameters for prediction of septic complications following surgery for colorectal endometriosis : A descriptive, retrospective study.

PURPOSE: To assess whether C­reactive protein (CRP), white blood cell count (WBC) and body temperature changes are suitable parameters for the early detection of septic complications following resection of colorectal deep endometriosis (DE). METHODS: Retrospective data analysis of CRP, WBC and body temperature courses following colorectal surgery for DE at a tertiary referral center for endometriosis. RESULTS: Out of 183 surgeries performed, 10 major surgical complications were observed, including 4 anastomotic leakages (AL 2%) and 2 rectovaginal fistulae (RVF 1%). In the presence of a lower gastrointestinal tract (GIT)-related septic complication or abdominal wall abscess, serum CRP levels were increased starting at postoperative day 2-3. A cut-off value of 10 mg/dl on day 4 for prediction of early septic complications could be verified (area under the curve 0.94, obtained by receiver operating characteristics analysis, sensitivity 88%, specificity 90%, positive predictive value 32%, negative predictive value 99%). Additionally, most patients with early septic complications exhibited increased WBC levels starting mainly from day 3-4; however, increased inflammatory parameters could not be observed in one patient with an RVF. Body temperature did not prove useful for early discrimination between uncomplicated cases and those with early septic complications. CONCLUSION: Relevant elevations of serum CRP and WBC levels were demonstrated in patients with early septic complications following surgery for colorectal DE starting at postoperative day 2-4. The cut-off value of 10 mg/dl for CRP levels may serve as an early predictor for lower GIT-related septic complications but should be used with caution in women with suspected RVF development.

Quantitative perfusion assessment of gastric conduit with indocyanine green dye to predict anastomotic leak after esophagectomy.

Impaired gastric conduit perfusion is a risk factor for anastomotic leak after esophagectomy. The aim of this study is to evaluate the feasibility of intraoperative quantitative assessment of gastric conduit perfusion with indocyanine green fluorescence angiography as a predictor for cervical esophagogastric anastomotic leak after esophagectomy. Indocyanine green fluorescence angiography using the SPY Elite system was performed in patients undergoing a transhiatal or McKeown esophagectomy from July 2015 through December 2020. Ingress (dye uptake) and Egress (dye exit) at two anatomic landmarks (the tip of a conduit and 5 cm from the tip) were assessed. The collected data in the leak group and no leak group were compared by univariate and multivariable analyses. Of 304 patients who were evaluated, 70 patients developed anastomotic leak (23.0%). There was no significant difference in patients' demographic between the groups. Ingress Index, which represents a proportion of blood inflow, at both the tip and 5 cm of the conduit was significantly lower in the leak group (17.9 vs. 25.4% [P = 0.011] and 35.9 vs. 44.6% [P = 0.019], respectively). Ingress Time, which represents an estimated time of blood inflow, at 5 cm of the conduit was significantly higher in the leak group (69.9 vs. 57.1 seconds, P = 0.006). Multivariable analysis suggested that these three variables can be used to predict future leak. Variables of gastric conduit perfusion correlated with the incidence of cervical esophagogastric anastomotic leak. Intraoperative measurement of gastric conduit perfusion can be predictive for anastomotic leak following esophagectomy.

The assessment of perioperative risk factors of anastomotic leakage after intestinal surgeries; a prospective study.

BACKGROUND: Anastomotic leaks (AL) are among the most serious complications due to the substantial impact on the quality of life and mortality. Inspite of the advance in diagnostic tools such as laboratory tests and radiological adjuncts, only moderate improvement has been recorded in the rate of detected leaks. The purpose of the research was to assess the perioperative risk factors for AL. METHODS: This study was achieved at MUH and MIH/Egypt within the period between January 2016 and January 2019 for the candidates who underwent bowel anastomosis for small intestinal (except duodenal one) and colorectal pathology. The collected data were analyzed using SPSS of V-26. RESULTS: This study included 315 cases, among them, 27 cases (8.57%) developed AL. The percentage of covering stoma was significantly higher in the non-leakage group vs leakage one (24.3% vs 11.1% respectively). lower albumin, operative timing, perforation, and covering stoma were shown as significant risk factors for leakage, but with multivariate analysis for these factors, the emergency operation, and serum albumin level was the only independent risk factors that revealed the significance consequently (p = 0.043, p = 0.015). The analysis of different predictors of AL on the third day showed that the cut-off point in RR was 29 with 83% sensitivity and 92% specificity in prediction of leakage, the cut-off point in RR was 118 with 74% sensitivity and 87% specificity in prediction of leakage and the cut-off point in CRP was 184.7 with 82% sensitivity and 88% specificity in prediction of AL and all had statistically significant value. CONCLUSIONS: The preoperative serum albumin level and the emergency operations are independent risk factors for anastomotic leakage. Moreover, leakage should be highly suspected in cases with rising respiratory rate, heart rate, and CRP levels.

Quantitative fluorescence-guided perfusion assessment of the gastric conduit to predict anastomotic complications after esophagectomy.

BACKGROUND: Fluorescence angiography (FA) assesses anastomotic perfusion during esophagectomy with gastric conduit reconstruction, but its interpretation is subjective. This study evaluated time to fluorescent enhancement in the gastric conduit, with the aim to determine a threshold to predict postoperative anastomotic complications. METHODS: In a prospective cohort study, all consecutive patients undergoing esophagectomy with gastric conduit reconstruction from July 2018 to October 2019 were included. FA was performed before anastomotic reconstruction following injection of indocyanine green (ICG). During FA, the following time points were recorded: ICG injection, first fluorescent enhancement in the lung, at the base of the gastric conduit, at the planned anastomotic site, and at ICG watershed or in the tip of the gastric conduit. Anastomotic complications including anastomotic leakage and clinically relevant strictures were documented. RESULTS: Eighty-four patients were included, the majority (67 out of 84, 80%) of which underwent an Ivor Lewis procedure. After a median follow-up of 297 days, anastomotic leakage was observed in 12 out of 84 (14.3%) and anastomotic stricture in 12 out of 82 (14.6%). Time between ICG injection and enhancement in the tip was predictive for anastomotic leakage (P = 0.174, area under the curve = 0.731), and a cut-off value of 98 seconds was derived (specificity: 98%). All times to enhancement at the planned anastomotic site and ICG watershed were significantly predictive for the occurrence of a stricture, however area under the curves were <0.7. CONCLUSIONS: The identified fluorescent threshold can be used for intraoperative decision making or to identify potentially high-risk patients for anastomotic leakage after esophagectomy with gastric conduit reconstruction.

Development and validation of the bile leakage grading criterion in patients following Roux-en-Y hepaticojejunostomy.

OBJECTIVE: The present research aimed to propose a severity grading criterion for bile leakage in pediatric patients after Roux-en-Y hepaticojejunostomy for choledochal cysts. SUMMARY BACKGROUND DATA: Despite a bile leakage classification system from the International Study Group of Liver Surgery (ISGLS) has been developed, a commonly used grading system for pediatric patients after Roux-en-Y hepaticojejunostomy has not yet been established. METHODS: A review of clinical, laboratory, and ultrasonographic parameters were used to develop a grading system for classifying the severity of bile leakage. A total of 267 patients with bile leakage were retrospectively assessed to review the system. RESULTS: We developed a grading system for bile leakage severity for use in pediatric patients following Roux-en-Y hepaticojejunostomy. By applying the criteria to 267 patients, grade I, II, or III bile leakage was determined in 103 patients (8.7%), 115 patients (9.8%), and 49 patients (4.2%) patients, respectively. The most severe bile leakage grade (grade III), was associated with significantly higher γ-glutamyl transpeptidase and amylase levels, greater drain fluid output, more intensive care unit (ICU) admissions, and longer postoperative hospital stay. Interestingly, patients with grade II leakage who underwent reoperation had significantly more ICU admissions, longer postoperative hospital stays (p < 0.05), and higher overall hospitalization cost (p < 0.05) compared with those who underwent conservation management. Of the patients with bile duct stricture and common bile duct (CBD) stones, there were no differences among the different grades of postoperative bile leakage. CONCLUSIONS: The proposed bile leakage criteria may optimize objective diagnosis and therapeutic modalities.

Development of a Risk Score to Predict Anastomotic Leak After Left-Sided Colectomy: Which Patients Warrant Diversion?

BACKGROUND: Anastomotic leak is a feared complication after left-sided colectomy, but its risk can potentially be reduced with the use of a diverting ostomy. However, an ostomy has its own associated negative sequelae; therefore, it is critical to appropriately identify patients to divert. This is difficult in practice since many risk factors for anastomotic leak exist and outside factors bias this decision. We aimed to develop and validate a risk score to predict an individual's risk of anastomotic leak and aid in the decision. METHODS: The American College of Surgeons National Surgical Quality Improvement Program Colectomy Targeted PUF was queried from 2012 to 2016 for patients undergoing elective left-sided resection for malignancy, benign neoplasm, or diverticular disease. Multivariable logistic regression identified predictors of anastomotic leak in non-diverted patients, and a risk score was developed and validated. RESULTS: 38,475 patients underwent resection with an overall anastomotic leak rate of 3%. Independent risk factors for anastomotic leak included younger age, male sex, tobacco use, and omission of combined bowel preparation. A risk score incorporating independent predictors demonstrated excellent calibration. There was strong visual correspondence between predicted and observed anastomotic leak rates. 3960 patients underwent resection with diversion, yet over half of these patients had a predicted leak rate of less than 4%. CONCLUSION: A novel risk score can be used to stratify patients according to anastomotic leak risk after elective left-sided resection. Intraoperative calculation of scores for patients can help guide surgical decision-making in both diverting the highest risk patients and avoiding diversion in low-risk patients.

Quantitative Assessment of Blood Flow in the Gastric Conduit With Thermal Imaging for Esophageal Reconstruction.

OBJECTIVE: The study's primary aim was to evaluate the effectiveness of thermal imaging (TI) and its secondary aim was to compare TI and indocyanine green (ICG) fluorescence angiography, with respect to the evaluation of the viability of the gastric conduit. SUMMARY BACKGROUND DATA: The optimal method for evaluating perfusion in the gastric conduit for esophageal reconstruction has not been established. METHODS: We reviewed the prospectively collected data of 263 patients who had undergone esophagectomy with gastric conduit reconstruction. TI was used in all patients. ICG fluorescence was concomitantly used in 24 patients to aid comparison with TI. A cut-off value of the anastomotic viability index (AVI) was calculated using the receiver operating characteristic curve in TI. RESULTS: Anastomotic leak was significantly less common in patients with AVI > 0.61 compared with those with AVI ≤ 0.61 (2% vs 28%, P< 0.001). Microvascular augmentation was performed in 20 patients with a low AVI score and/or preoperative chemoradiotherapy. Overall ability was comparable between TI and ICG fluorescence regarding the qualitative evaluation of the gastric conduit. However, TI was superior in the quantitative assessment of viability. CONCLUSIONS: TI could delineate the area of good perfusion in the gastric conduit for esophageal reconstruction, which can help identify patients at high risk of anastomotic leak.

Detection of early anastomotic leakage by intraperitoneal microdialysis after low anterior resection for rectal cancer: a prospective cohort study.

AIM: Anastomotic leakage (AL) is a common and serious complication following sphincter-preserving surgery for rectal cancer. Early detection and intervention can improve clinical outcomes. The aim of this prospective cohort study was to compare intraperitoneal microdialysis with a clinical scoring system for early detection of AL. METHOD: A microdialysis catheter was anchored near the anastomosis at low anterior resection (LAR) for rectal cancer. Peritoneal fluid samples were analysed (lactate, pyruvate, glucose and glycerol concentration) 4-hourly and compared with a daily clinical leak score (DULK = Dutch leakage). At day 7 a pelvic CT with rectal contrast enema was performed to establish if there had been a radiological leak. RESULTS: In this two-centre study, 129 patients [median age 65 (26-82) years; 60.5% male] underwent LAR. The leak rate was 27% (grade A, n = 11; grade B, n = 12; grade C, n = 12). Receiver operator characteristic analysis demonstrated a lactate cut-off value of 9.8 mm and had 77% sensitivity, 82% specificity, 78% accuracy, a positive predictive value (PPV) of 58, a negative predictive value (NPV) of 88 (CI 79-94) and an area under the curve (AUC) of 0.9 for AL. This compared with a clinical score ≥ 4, which had 57% sensitivity, 79% specificity, 71% accuracy, a PPV of 46, a NPV of 82 and an AUC of 0.7 for AL. The mean day for a positive test when using delta lactate ≥ 6.3 mm was 1.6 days and for leak score ≥ 4 it was 3.3 days (NS). CONCLUSION: When AL occurs, intraperitoneal lactate concentration increases over time, and at a certain cut-off has a higher sensitivity, specificity, accuracy, PPV and NPV than a clinical scoring system.

Assessment of the Value of Comorbidity Indices for Risk Adjustment in Colorectal Surgery Patients.

BACKGROUND AND PURPOSE: Comorbidity indices (CIs) are widely used in retrospective studies. We investigated the value of commonly used CIs in risk adjustment for postoperative complications after colorectal surgery. METHODS: Patients undergoing colectomy without stoma for colonic neoplasia at a single institution from 2009 to 2014 were included. Four CIs were calculated or obtained for each patient, using administrative data: Charlson-Deyo (CCI-D), Charlson-Romano (CCI-R), Elixhauser Comorbidity Score, and American Society of Anesthesiologists classification. Outcomes of interest in the 90-day postoperative period were any surgical complication, surgical site infection (SSI), Clavien-Dindo (CD) grade 3 or higher complication, anastomotic leak or abscess, and nonroutine discharge. Base models were created for each outcome based on significant bivariate associations. Logistic regression models were constructed for each outcome using base models alone, and each index as an additional covariate. Models were also compared using the DeLong and Clarke-Pearson method for receiver operating characteristic (ROC) curves, with the CCI-D as the reference. RESULTS: Overall, 1813 patients were included. Postoperative complications were reported in 756 (42%) patients. Only 9% of patients had a CD grade 3 or higher complication, and 22.8% of patients developed an SSI. Multivariable modeling showed equivalent performance of the base model and the base model augmented by the CIs for all outcomes. The ROC curves for the four indices were also similar. CONCLUSIONS: The inclusion of CIs added little to the base models, and all CIs performed similarly well. Our study suggests that CIs do not adequately risk-adjust for complications after colorectal surgery.