A study investigating the perfusion of colorectal anastomoses using fluorescence angiography: results of the FLAG randomized trial.

AIM: Our aim was to evaluate the efficacy of indocyanine green (ICG) fluorescence angiography (FA) in reducing the incidence of anastomotic leakage (AL) following colorectal anastomosis.

METHOD: A single-centre randomized trial was undertaken between 2018 and 2019. Those patients who underwent a stapled colorectal anastomosis were randomized 1:1 for ICG FA versus visual clinical assessment of blood perfusion of the anastomosed colon and rectal stump (non-ICG FA group). The primary end-point was to assess whether ICG FA was associated with a reduction in the incidence of AL. Secondary outcomes were the rate of postoperative complications and change in the level of bowel resection.

RESULTS: A total of 380 patients undergoing sigmoid and rectal resection were enrolled. After randomization, three patients were excluded. The results of 377 cases were available for analysis; 187 had ICG FA and 190 were in the non-ICG FA group. ICG FA identified impaired blood perfusion of the colon in 36 (19%) cases. An AL (grade A, B or C) developed in 48 patients: 17 (9.1%) in the ICG FA group and 31 (16.3%) in the non-ICG FA group (P = 0.04). ICG FA did not decrease the rate of AL of high anastomoses (9-15 cm from the anal verge), at 1.3% vs 4.6% in the non-ICG FA group (P = 0.37). In contrast, a decrease in AL rate was found for low (4-8 cm) colorectal anastomoses (14.4% in ICG FA vs 25.7% in the non-ICG FA group; P = 0.04).

CONCLUSION: ICG FA is associated with a reduction in AL following low anterior resection.