The Use of Indocyanine Green Fluorescent Angiography (LUNA) to Follow Improvements in Wound Healing After Application of a Fresh Amniotic Membrane

Background: Indocyanine Green Fluorescent Angiography measures skin perfusion. Serial image analysis permits clinicians to follow angiogenesis during the healing process. In short, vascular endothelial growth factor (VEGF) promotes blood vessel growth and increases capillary permeability. As a result, areas with high levels of VEGF have leaky capillaries, which lead to an area of greater fluorescence on the Angiography image. Cellular or Tissue Based products (CTPs), such as fresh hypothermically stored amniotic membrane (HSAM), promote wound healing. It is thought that CTPs support the extracellular matrix and increase growth factor production; however, the mechanism of action (MOA) for these products has not been evaluated in vivo.

Methods: As part of an MOA trial, venous leg ulcers were imaged with the Angiography device prior to the application of HSAM and weekly thereafter for four weeks. A total of 15 patients with venous leg ulcers between 2 to 20 cm² were enrolled in an IRB-approved prospective, single-center clinical trial. All patients underwent Angiography imaging prior to graft application and weekly thereafter for four weeks. Image analysis included calculation of the variability index (VI). The VI measures the amount of fluorescence in the skin and is an indirect measure of VEGF-induced angiogenesis.

Results: In conclusion, the images demonstrate an increase in VI post grafting indicating increased angiogenesis in the wound. This correlates with healing of the ulcers