Laser-Assisted Indocyanine Green Angiography A Critical Appraisal

Background: Laser-assisted indocyanine green angiography (ICG-A) has been promoted to assess perfusion of random skin, pedicled, and free flaps. Few studies address its potential limitations. Methods: Thirty-seven patients who underwent reconstructive procedures with ICG-A were studied retrospectively to determine the correlation between clinical findings and ICG-A. Indocyanine green angiography underestimated perfusion when areas of less than or equal to 25% uptake were not debrided and remained perfused. Indocyanine green angiography overestimated perfusion when areas with greater than 25% uptake developed necrosis. Results: Of 14 random skin flaps, ICG-A underestimated perfusion in 14% and overestimated in 14%. In 16 patients undergoing perforator flap breast reconstruction, ICG-A correlated with computed tomographic angiogram (CTA) in 85%. Indocyanine green angiography underestimated perfusion in 7% and overestimated in 7%. In 8/11 patients undergoing fasciocutaneous flaps, ICG-A aided in donor site selection. In 3/6 ALT flaps, a better unilateral blush was found that correlated with Doppler. In all 3, a dominant perforator was found. In 11 patients, there was a 9% underestimation of flap perfusion. In 3 pedicled flaps, there was a 66% underestimation and 33% overestimation of perfusion. Conclusions: Indocyanine green angiography often confirmed our clinical/radiologic findings in abdominal perforator and fasciocutaneous flaps. It tended to underestimate perfusion in pedicle and skin flaps. When clinical examination was obvious, ICG-A rendered clear-cut findings. When clinical examination was equivocal, ICG-A tended to provide ambiguous findings, demonstrating that a distinct cutoff point does not exists for every patient or flap. Indocyanine green angiography is a promising but expensive technology that would benefit from standardization. Further research is needed before ICG-A can become a reliable tool for surgeons.