Assessment of Microcirculation of an Axial Skin Flap Using Indocyanine Green Fluorescence Angiography

Abstract

In many cases the complexities of skin-flap microcirculation are difficult to assess despite all the subjective and objective examination techniques available today. Adequate microcirculation is essential for tissue viability, so any method employed for studying microcirculation should provide as accurate an assessment of the prevailing conditions as possible. Of all the clinical methods, the fluorescence technique using the dye sodium fluorescein has so far provided the most reliable results. However, the pharmacokinetic properties of this tracer have prevented the technique from becoming established in clinical practice. The fluorescent dye indocyanine green (Cardio Green), on the other hand, has far more favorable pharmacokinetics. In an experimental animal model, the fluorescence technique using indocyanine green (indocyanine green angiography, ICGA) was used to study postoperative changes in the microcirculation of a skin flap. On the day of operation, indocyanine green angiography revealed a state of hemodynamic imbalance for which the organism was able to compensate in the postoperative phase with the aid of humoral, physical, and metabolic factors. With indocyanine green angiography it was possible to quantify objectively the new hemodynamic equilibrium. Basically, microcirculation may be quantified in temporal and spatial terms. The significant objectivity of indocyanine green angiography and short intervals between each examination favor its possible and meaningful use in clinical practice and give cause for continuing studies.