Indocyanine Green Angiography for Continuously Monitoring Blood Flow Changes and Predicting Perfusion of Deep Inferior Epigastric Perforator Flap in Rats.

Deep inferior epigastric perforator (DIEP) flap approach has excellent outcomes and low morbidity. However, it is associated with high rates of perfusion-related complications. To observe the blood flow changes and the stages of the flap perfusion, as well as the necrosis formation, we used indocyanine green (ICG) to monitor its perforators before and after DIEP flap harvesting. Methods: Abdominal perforator flaps supplied by the right superior abdominal perforating arteries were generated from seven SD rats. Laser-assisted ICG angiography was applied for dynamical and continuous observation of changes in the blood flow and courses of flap perfusion. Areas of flap perfusion were quantitatively analyzed using ImageJ. Results: The average perfusion area of the seven flaps after surgery and at days 1, 2, and 3 after surgery were 23.06 ± 2.47, 22.48 ± 2.04, 28.34 ± 1.14, and 28.97 ± 2.44 cm2, respectively. Compared to values after surgery, no significant difference was observed on day one (p > 0.05); however, the flaps had significantly improved perfusion areas on day 2 (mean value of 5.28 ± 1.83 cm2, p < 0.01) and day 3 (mean value of 5.91 ± 2.60 cm2, p < 0.01) postsurgery. In addition, there were no significant differences between days 2 and 3 (p > 0.05). The blood flow changes in both arteries and veins, the stages of flap perfusion, and the development of necrosis at the distal end of the flap were also observed. Conclusion: We gained valuable knowledge on the dynamic of blood flow changes and the course of flap perfusion inside the DIEP flap. Dynamic and continuous observation with ICG angiography through an SPY system is a powerful method for monitoring of blood supply in flaps that can be used to predict flap perfusion with a strong positive predictive significance.