Utilizing Indocyanine Green Dye Angiography to Detect Simulated Flap Venous Congestion in a Novel Experimental Rat Model

Abstract Background Venous congestion is a leading cause for free flap failure and still relies on clinical observation as the diagnostic gold standard. We sought to characterize blood flow in a variable venous congestion murine hind limb model using indocyanine green (ICG, SPY Pack, LifeCell, Branchburg, NJ) angiography. Methods Male Sprague–Dawley rats (Charles River, Hudson, NY) underwent bilateral partial amputation at the inguinal ligament, leaving only the femoral vessels and femur intact. Complete unilateral venous occlusion was achieved via suture ligation, while partial occlusion was achieved by surrounding the femoral vein with a synthetic microtube to achieve 25, 75, 85, or 92% occlusion. Relative blood flow of occluded and control limbs was tracked with ICG angiography throughout a 90-minute time course. Results ICG angiography detected statistically significant ( p