Quality Control of the Foot Revascularization Using Indocyanine Green Fluorescence Imaging

Abstract

Objectives Critical limb ischemia (CLI) is a clinical diagnosis, confirmed by objective tests, usually ankle-brachial index (ABI), toe pressure (TP) and TcPO2. Furthermore, the anatomical lesions in patients affected by CLI were visualized by ultrasound, angiography, CTA, or MRA. Indocyanine green fluorescence imaging (ICG-FI) is a diagnostic modality for assessing foot perfusion. We aimed to study the usefulness of ICG-FI in the quality control of revascularization. Materials and methods One hundred and four CLI limbs in 101 patients were studied with ICG-FI using SPY Elite before and after open or endovascular revascularization. ABI and TP were also measured. After ICG-FI, assessment of circulation was done using time-intensity curve derived from the two regions of interest the one being in the plantar side of the foot and the other in the dorsal side of the foot. Three parameters were derived from the curves: maximum intensity (the absolute value of the maximum intensity); intensity rate (the value from the time-intensity curve describing the increase in maximum intensity/s) and SPY10 (the intensity achieved during the first 10 s after the foot starts to gain intensity). Results Sixty-two limbs presented category 3 of Rutherford classification, 12 limbs category 4, and 30 limbs category 5. Ninety-five technically successful procedures were achieved, 63 (66.3%) endovascular and 32 (33.7%) surgical revascularizations. In 9 (9.5%) patients, an in-line flow from the aorta to the foot was not achieved due to a failure to recanalize the occlusion (n = 7) or due to distal embolization (n = 2). ABI was not reliable in 58 patients (57.4%) mostly due to pseudohypertension and TPs in 49 (48.5%) patients mostly due to previous minor amputations. ICG-FI was successful in all patients. The mean intensity values before and after the procedure in patients who underwent successful revascularization were 81 ± 47 units and 120 ± 5 units of intensity (p \ .001) and intensity rates 4.2 ± 4 and 8.0 ± 6.2 units/s (p = .001), respectively. In the PTA patients in whom the revascularization was unsuccessful, no changes were seen in the hemodynamic parameters. In 6 (8.8%) patients who underwent technically successful revascularization, the SPY values were worse after the revascularization than at the baseline. Conclusions ICG-FI with SPY Elite provides reliable information on the increase in perfusion after revascularization, in addition to implicating possible failure if there is no improvement in the ICG-FI variables. Unlike ABI and TP, it can be performed in all patients. It gives valuable information to complement traditional assessment methods.

Perfusion Parameters in Near-Infrared Fluorescence Imaging with Indocyanine Green: A Systematic Review of the Literature

“…Quantitative analysis of fluorescence imaging was conducted in 18 studies included in this review ( n = 683) [ 8 , 11 , 12 , 15 , 16 , 18 , 20 , 29 , 30 , 38 , 39 , 40 , 43 , 44 , 50 , 55 , 60 , 65 ]. Fifteen studies opted for dose-dependent ICG administration, with 10 studies selecting a dose of 0.1 mg/kg [ 12 , 15 , 16 , 20 , 29 , 30 , 38 , 39 , 40 , 43 , 44 , 50 , 55 , 60 , 65 ]. SPY Elite Imaging was the fluorescence imaging system of choice in eight studies, see Table 2 .…”

“…The PDE10, described as the fluorescence intensity increase at 10 s, was examined in four studies [ 29 , 44 , 60 , 65 ]. Two studies stated a statistically significant change in the PDE10 in PAD patients following a revascularization procedure [ 29 , 44 ].…”

Predictors of Wound Healing Following Revascularization for Chronic Limb-Threatening Ischemia

“…56 The ICG-FI is a promising tool in the assessment of change in foot perfusion after revascularization as well as quality control of the procedure. 57,58 More studies are needed to assess the value of ICG-FI in the wound healing. Another novel method of microcirculation assessment, namely, the multispectral optoacoustic tomography, combines optical imaging with conventional ultrasound.…”

On the Cutting Edge: Wound Care for the Endovascular Specialist

“…Quantitative ICG NIFA analysis performed before and after revascularization demonstrates correlation with standard perfusion analyses, such as ABIs, and has been shown to predict revascularization success or failure. [70][71][72] Furthermore, ICG NIFA has been shown to reflect differences in perfusion in patients after revascularization even in situations where other perfusion techniques such as ABI and toe pressure often fail, such as in diffuse medial calcification, making its use evident in the CLI patient. 71,[73][74][75] Fig.…”

“…[70][71][72] Furthermore, ICG NIFA has been shown to reflect differences in perfusion in patients after revascularization even in situations where other perfusion techniques such as ABI and toe pressure often fail, such as in diffuse medial calcification, making its use evident in the CLI patient. 71,[73][74][75] Fig. 8 HTOM with the HyperView device (HyperMed Imaging) uses a handheld spectrometer (a) to quantify tissue perfusion and viability via the absorption of visible light in hemoglobin molecules over a region of interest.…”