eP267 - Fluorescence Angiography with Indocyanine Green for Low Anterior Resection in Patients with Rectal Cancer: A Prospective Before and After Study

Purpose/Background: Multiple risk factors have been identified for anastomotic leaks in colorectal surgery, including inadequate anastomotic bowel perfusion. This can be assessed perioperatively with indocyanine green fluorescence angiography during colon resections. Possible benefits from its systematic use in high-risk patients with rectal cancer and associated anastomotic leaks remain inconsistent.This study aimed to evaluate the surgical modifications induced by indocyanine green assessment during rectal cancer surgery and associated anastomotic leaks.Methods/Interventions: This is a Canadian before and after cohort study, conducted at a single high-volume colorectal surgery center. Patients undergoing low anterior resection for rectal cancer within 15cm from anal margin were prospectively included in the experimental group, from 2019 to 2020. They underwent surgery using fluorescence angiography with indocyanine green. This technology was used twice during surgery: after full colon mobilization and vessels ligation (time 1), and then after final bowel transection, right before completion of the anastomosis (time 2). This experimental cohort was compared to a retrospective control group, consisting of patients with the same disease, who underwent the same procedure prior to the introduction of indocyanine green technology. Patients with stapled or handsewn coloanal anastomoses were eligible.The main outcomes were the rates of modifications from planned anastomosis dictated by indocyanine green evaluation and rates of anastomotic leaks. Handsewn coloanal anastomoses were specifically analyzed.Results/Outcomes: Each cohort included 113 patients. There were 79 stapled anastomoses and 34 handsewn coloanal anastomoses, in each group. Both arms were comparable for patients’ characteristics and surgical features, including anastomosis height and neoadjuvant radiation. Operative techniques and perioperative protocols were standardized. Intraoperative fluorescence angiography's time 1 was performed in 99.1% of patients. Indocyanine green’s use led to modifications from initial surgical plan in 10.6% of patients, with no occurrence of anastomotic leaks in this specific group. When comparing anastomotic leak rates, using indocyanine green seemed to be protective, but this could not be statistically proven, overall (13.3% vs. 6.2%, p-value 0.07) , neither for handsewn coloanal anastomoses (11.8% vs. 5.9%, p-value 0.67). However, mean length of hospital stay was significantly reduced among patients with leaks, for whom indocyanine green was used (11.9 days vs. 5.67 days, p-value 0.02).Conclusion/

Discussion: Fluorescence angiography influenced ultimate proximal resection margin in a relevant proportion of cases. It might be associated with reduced leak rates, although not formally proven with this data. While no difference was shown in reintervention rates, length of hospital stay among patients with anastomotic leaks was significantly shorter in the indocyanine green group, suggesting the clinical impact of those leaks could be lessened by the use of this technology. A lack of power could explain some non-significant results, especially with overall low anastomotic leak rates recorded. Overall, fluorescence angiography is safe and easy to use and apply in high-volume colorectal surgery centers."Changes in surgical plan following fluorescence angiography

Anastomotic leaks at 30 days
"