Quantitative analysis of colon perfusion pattern using indocyanine green (ICG) angiography in laparoscopic colorectal surgery

PURPOSE: This study aimed to quantitatively evaluate colon perfusion patterns using indocyanine green (ICG) angiography to find the most reliable predictive factor of anastomotic complications after laparoscopic colorectal surgery. METHODS: Laparoscopic fluorescence imaging was applied to colorectal cancer patients (n = 86) from July 2015 to December 2017. ICG (0.25 mg/kg) was slowly injected into peripheral blood vessels, and the fluorescence intensity of colonic flow was measured sequentially, producing perfusion graphs using a video analysis and modeling tool. Colon perfusion patterns were categorized as either fast, moderate, or slow based on their fluorescence slope, T(1/2MAX) and time ratio (TR = T(1/2MAX)/T(MAX)). Clinical factors and quantitative perfusion factors were analyzed to identify predictors for anastomotic complications. RESULTS: The mean age of patients was 65.4 years, and the male-to-female ratio was 63:23. Their operations were laparoscopic low anterior resection (55 cases) and anterior resection (31 cases). The incidence of anastomotic complication was 7%, including colonic necrosis (n = 1), anastomotic leak (n = 3), delayed pelvic abscess (n = 1), and delayed anastomotic dehiscence (n = 1). Based on quantitative analysis, the fluorescence slope, T(1/2MAX), and TR were related with anastomotic complications. The cut-off value of TR to categorize the perfusion pattern was determined to be 0.6, as shown by ROC curve analysis (AUC 0.929, P < 0.001). Slow perfusion (TR > 0.6) was independent factor for anastomotic complications in a logistic regression model (OR 130.84; 95% CI 6.45–2654.75; P = 0.002). Anastomotic complications were significantly correlated with the novel factor TR (> 0.6) as the most reliable predictor of perfusion and anastomotic complications. CONCLUSIONS: Quantitative analysis of ICG perfusion patterns using T(1/2MAX) and TR can be applied to detect segments with poor perfusion, thereby reducing anastomotic complications during laparoscopic colorectal surgery.