Perfusion Angiography with Indocyanine Green Fluorescence in Patients With Critical Ischemia

Perfusion, or the steady state nutritive delivery of blood to the tissue capillary bed, is vital for the survival of tissue. Accurate perfusion measurement can provide important diagnostic and prognostic information. Precise measurement of functional tissue perfusion is needed for preventive measures, early diagnosis, and adequate treatment, especially in the patients with peripheral vascular diseases. Higher rates of tissue salvage not only improve the patient's quality of life but also positively impact the closure and healing rates of an open wound from a partial amputation or incision. The SPY Elite System (Novadaq Technologies, Ontario, Canada; LifeCell, Branchburg, NJ) allows perfusion evaluation by using the fluorescent properties of indocyanine green dye. Although this technology has been used for decades in ophthalmology, its introduction to plastic reconstructive surgery and vascular surgery is relatively recent. It can be used in the intraoperative or postoperative setting to visually assess superficial blood flow. The indocyanine green dye is administered, and the device's infrared laser stimulates the fluorescent properties of the dye, allowing real-time, dynamic images to have an angiogram-like character, making them clear and easy to read. We present pilot case studies (n = 5), where the SPY Fluorescence Imaging Device was used to determine real-time perfusion analysis after angiographic intervention in patients with critical ischemia. These prospective case studies demonstrate feasibility and utility of laser-assisted fluorescent angiography in the periprocedure evaluation of patients with critical ischemia. Qualitative and quantitative fluorescent images provide real-time and objective assessments of pedal tissue perfusion. Laser-assisted fluorescent angiography-derived peak pedal perfusion and ingress slope provide objective measurements of tissue perfusion that correlate with conventional methods using ankle-brachial indices. This technology continues to see new promising applications in many areas of surgery, including colorectal surgery, surgical oncology, and microvascular lymphedema treatment to name a few. To date there has been a paucity of literature published on how this technology can be used in vascular surgery. With further study, we anticipate that this technology may be a helpful adjunct for intra-procedural decision making and predicting wound healing capacity.