Quantification of sigmoid perfusion with near-infrared fluorescence and indocyanine green during open abdominal aortic aneurysm reconstruction.

OBJECTIVE

This study evaluated the feasibility of quantitative near-infrared fluorescence imaging with indocyanine green (NIRF-ICG) to assess changes in colon perfusion induced by abdominal aortic aneurysm reconstruction. Improved perfusion assessment may support clinical decision-making in patients at risk for developing colon ischemia.

METHODS

NIRF-ICG recordings of the sigmoid colon from 25 patients treated at a single center were retrospectively analyzed. Time-intensity curves were extracted from the sigmoid colon and small intestine and classified as demonstrating adequate, questionable, or poor perfusion. Four curve-derived perfusion parameters (time to maximum intensity, maximum inflow rate of the normalized curve, and remaining fluorescence intensity 30 seconds and 60 seconds after maximum intensity) were compared to objectively evaluate changes in fluorescence inflow and outflow before and after aortic reconstruction.

RESULTS

Quantitative analysis was feasible in 23 patients undergoing elective procedures and in 1 patient undergoing acute surgery. Although all patients demonstrated adequate perfusion on clinical assessment, quantitative classification identified perfusion deterioration in 13 patients. All four derived perfusion parameters showed a significant decrease in sigmoid perfusion after aortic reconstruction (time to maximum intensity, P < .001; maximum inflow rate of the normalized curve, P = .019; remaining fluorescence intensity 30 seconds after maximum intensity, P = .029; remaining fluorescence intensity 60 seconds after maximum intensity, P = .021), whereas small intestinal perfusion remained unchanged (all P > .05). In two cases, severely impaired perfusion detected by NIRF-ICG imaging recovered postoperatively, as confirmed by a NIRF-ICG measurement during planned second-look surgery. Two patients classified as having poor perfusion required acute relaparotomy due to anastomotic bleeding. There were no cases of colon ischemia, and mortality was zero.

CONCLUSIONS

Quantitative NIRF enables objective intraoperative assessment of sigmoid perfusion during open abdominal aortic aneurysm repair. The observed recovery from transient perfusion deficits supports heightened awareness rather than immediate bowel resection in cases suspected of malperfusion. Validation of perfusion patterns predictive of ischemia is required to establish risk stratification criteria and optimize clinical decision-making.