Noninvasive measurements of tissue perfusion in critical limb ischemia

Abstract

Critical limb ischemia (CLI) remains a challenge for an interdisciplinary therapeutic team due to chronic nonhealing wounds. Against this background, there is a necessity of quality control after revascularization. Beside the isolated evaluation of the macrocirculation by Ankle-Brachial or Toe-Brachial Index measurements, the microcirculation as an additional important factor of wound healing often remains underestimated. The following article gives an overview about the current investigation methods for noninvasive perfusion control of the CLI patient. Therefore, transcutaneous oxygen pressure (tcpO2), the “oxygen-to-see” method which is a combination of white light tissue spectrometry and laser-Doppler flowmetry, fluorescence angiography with indocyanine green, and multispectral optoacoustic tomography will be described.

Quantitative assessment of microperfusion by indocyanine green angiography in kidney transplantation resembles chronic morphological changes in kidney specimens

“…The operating room was shaded, and the fluorescence dye ICG (ICG, ICG‐Pulsion Medical Systems, Germany or Verdye, Diagnostic Green, Belgium) was injected systemically via a central venous catheter 5 minutes after reperfusion of the kidney (Figure ). As published previously, a standardized dose of 0.02 mg ICG/kg body weight was applied, ensuring a comparable quantitative assessment . After the application of the fluorescence dye, measurements were conducted for a time period of 138 seconds to monitor the organ inflow and outflow.…”

Wound closure by means of free flap and arteriovenous loop: Development of flap autonomy in the long‐term follow‐up

“…The perfusion sequence is then displayed in a video sequence, which can be analysed and quantified afterwards by an integrated analysis software (SPY‐Q). ICG is a water‐soluble tricarbocyanine dye that has been widely used for various medical indications; it can be safely used in renal insufficient patients as it is metabolised by the hepato‐biliary system . In this study, we intravenously applied a standardised dose of 0.1 mg ICG per kg body weight.…”

On the Cutting Edge: Wound Care for the Endovascular Specialist

“…Reports in the literature demonstrate that up to 10 to 18% of chronic wounds fail to heal even after successful macrovascular reconstruction. [59][60][61][62] Therefore, the assessment of "sufficient tissue perfusion" for wound healing is an area of active investigation and continues to evolve. Two-dimensional perfusion angiography, methylene blue angiography, transcutaneous measurement of oxygen partial pressure (tcPO 2 ), multispectral optoacoustic tomography, hyperspectral tissue oxygenation measurement (HTOM), and nearinfrared fluorescence angiography (NIFA) have all demonstrated promise in the assessment of distal perfusion and Fig.…”

“…tissue viability prior to and during debridement. 62 We have found HTOM and NIFA to be particularly effective in our multidisciplinary CLI practice, as they allow real-time, intraoperative assessment of the impact of revascularization on wound perfusion.…”

“…67,68 First used in 1959 to assess liver function and cardiac output, it has been regularly used for ophthalmological measurement of retinal and choroidal blood flow as well as for flap perfusion analysis in reconstructive plastic surgery. 62 After intravenous injection, ICG binds to plasma proteins and is excited to fluorescence by a nearinfrared light source. 67,69 Handheld cameras employing silicon and indium gallium arsenide are then used to measure the emitted light within the optical near-infrared range (700-1,299 nm) from the ICG-bound plasma proteins near the skin surface down to 2 to 4 cm in depth, serving as a surrogate for superficial tissue perfusion.…”