Evaluation of graft anastomosis using time-intensity curves and quantitative near-infrared fluorescence angiography during peripheral arterial bypass grafting

Indocyanin Green Fluorescence Evaluation of Colonic Perfusion During Elective Open Abdominal Aortic Aneurysm Repair

OBJECTIVES

Colonic ischaemia is a rare but devastating complication of open aortic aneurysm repair and is associated with high morbidity and a mortality of up to 50%. The aim of this study was to determine the safety and effectiveness of using indocyanin green florescence (ICG) to interrogate colonic perfusion intra-operatively.

DESIGN

Prospective observational study.

METHODS

All elective open abdominal aneurysm repairs over a 6 month period underwent colonic perfusion interrogation with ICG according to a pre-defined protocol. Patient demographics and imaging findings were recorded prior to surgery. ICG was given just prior to laparotomy closure. Time to florescence was measured from the start of IV administration to surgeon defined maximal florescence of the sigmoid colon.

RESULTS

Ten patients fulfilled the inclusion criteria. All patients were male with an average age of 69.7 years. Inferior mesenteric artery reimplantation was performed in 5 patients. Median colonic fluorescence time was 58 s. No complications related to ICG were identified. A single patient had clinical concern of colonic ischaemia and delayed perfusion (>3 min) on ICG; colorectal opinion advised not for immediate resection. At relook laparotomy, ischaemic colon at the area of demarcation was noted and a Hartmann's procedure was performed. No other patients had delayed perfusion and no further episodes of colonic ischaemia were noted. IMA reimplantation did not show statistical difference in colonic ICG time (P = .81, 95% CI -1.98 to 2.45). There was no statistical difference between operating times between the cohort and all repairs performed 6 months before the data collection (P = .59, 95% CI -.73 to 1.24).

CONCLUSION

In this pilot study ICG appears to be a safe and useful adjunct in objective assessment of colonic perfusion during open AAA repair. Further research is required to fully determine its role in this cohort of patients.

Anastomotic stenosis of a reconstructed dissecting superior mesenteric artery aneurysm undetectable by intraoperative indocyanine green angiography: A case report

Intraoperative evaluation of blood flow using ICG angiography revealed no significant abnormality. However, the anastomotic stenosis was revealed by postoperative CT angiography; more precise intraoperative evaluation methods need to be developed.

Quantifying tissue perfusion after peripheral endovascular procedures: Novel tissue perfusion endpoints to improve outcomes

Peripheral artery disease (PAD) is a flow-limiting condition caused by narrowing of the peripheral arteries typically due to atherosclerosis. It affects almost 200 million people globally with patients either being asymptomatic or presenting with claudication or critical or acute limb ischemia. PAD-affected patients display increased mortality rates, rendering their management critical. Endovascular interventions have proven crucial in PAD treatment and decreasing mortality and have significantly increased over the past years. However, for the functional assessment of the outcomes of revascularization procedures for the treatment of PAD, the same tests that have been used over the past decades are still being employed. Those only allow an indirect evaluation, while an objective quantification of limb perfusion is not feasible. Standard intraarterial angiography only demonstrates post-intervention vessel patency, hence is unable to accurately estimate actual limb perfusion and is incapable of quantifying treatment outcome. Therefore, there is a significant necessity for real-time objectively measurable procedural outcomes of limb perfusion that will allow vascular experts to intraoperatively quantify and assess outcomes, thus optimizing treatment, obviating misinterpretation, and providing significantly improved clinical results. The purpose of this review is to familiarize readers with the currently available perfusion-assessment methods and to evaluate possible prospects.

Evolution of photodynamic medicine based on fluorescence image-guided diagnosis using indocyanine green and 5-aminolevulinic acid

New diagnostic techniques based on photodynamic medicine, such as near-infrared fluorescence using indocyanine green (NIR-ICG) and 5-aminolevulinic acid-mediated photodynamic diagnosis (ALA-PDD), are aiding navigation tasks across various fields of surgery. Specifically, NIR-ICG is being used for the intraoperative identification of sentinel lymph nodes or blood vessels in organ resection and for blood flow evaluation in surgery. These ICG-fluorescent imaging techniques could provide an additional and potentially valuable way to identify vascular and lymphatic structures in surrounding tissue. 5-Aminolevulinic acid is a precursor of a photosensitizing substance with affinity for tumors; thus, diagnostic laparoscopy using ALA-PDD in combination should improve the accuracy of detecting peritoneal dissemination in patients with advanced gastric cancer. The ability to overlay fluorescent imaging with conventional color images in real time using ALA-PDD and NIR with ICG would be of immense benefit to surgeons, providing good visualization and detection of target lesions not seen with the naked eye. A multi-center clinical study examining the safety and efficacy of ALA-PDD during laparoscopic examination for patients with advanced gastric cancer is currently underway in the form of doctor-initiated trials, and further verification studies will be conducted. Such imaging capability could have broad potential across cancer and vascular surgery.

Influence of residual coronary flow on bypass graft flow for graft assessment using near-infrared fluorescence angiography

PURPOSE

Near-infrared fluorescence angiography (NIR) detects the attenuation of fluorescence luminance intensity (FLI) through coronary artery bypass grafts affected by anastomotic stenosis. This study investigates the influence of residual blood flow of the host coronary artery (Ho) on bypass graft (Gr) FLI using a coronary artery bypass (CABG) model.

METHODS

A mock circuit system was created using artificial vessels and artificial blood was supplied to the Gr and the Ho. We used NIR to examine the changes in FLI through the Gr.

RESULTS

The Gr FLI was significantly attenuated according to the degree of Gr stenosis. The Gr FLI did not differ significantly among all degrees of Ho stenosis. High FLI grafts included grafts with degrees of Gr stenosis ≤ 75%, regardless of the severity of Ho stenosis. Moderate and low FLI grafts had 90 or 99% Gr stenosis, regardless of the severity of Ho stenosis. Gr FLI with 99% Gr stenosis was higher in 99% Ho stenosis than in ≤ 90% Ho stenosis.

CONCLUSIONS

A high Gr FLI indicated the absence of ≥ 90% stenosis in the anastomosis and a low Gr FLI indicated severe stenosis in the anastomosis despite Ho stenosis. High Ho stenosis may prevent the attenuation of Gr FLI in severely stenosed grafts.