Here’s how to use objective data to monitor your revascularization patients
Use NIRS to enhance your patient monitoring
Using near-infrared spectroscopy (NIRS) when evaluating and monitoring your revascularization patients can give you insights beyond just a simple pulse check.
Occluded arteries in the lower limb can lead to devastating consequences for the patient. Having tools to repeatedly measure tissue oxygenation (StO2) status throughout the post-intervention stages can reveal what is happening beneath the skin and in the blood vessels supplying the ischemic angiosome.
SnapshotNIR is one of those tools, allowing clinicians to see beneath the skin using NIRS.
SnapshotNIR being used on a patient with a foot injury.
What types of revascularization procedures can SnapshotNIR be useful for?
Patients with diabetes and peripheral arterial disease (PAD) are particularly susceptible to atherosclerotic changes to the blood vessels below the knee (1). When these patients are assessed, in addition to doppler measures, SnapshotNIR can assess for a potential need of a revascularization procedure. The aim of these procedures is to improve peripheral circulation to reduce ischemia and perfusion to the areas that may be suffering from a chronic wound, the end goal being limb preservation. (1).
Two common approaches are open reconstructive or endovascular surgery (1)
There are often multiple options for revascularization that a surgeon can decide upon for a patient. An important consideration is to always attempt an endovascular first approach to reduce the risk of operative complications for these patients (2). A second consideration is to attempt an angiosomal-targeted procedure.
Although there is no current consensus on the best practice for revascularization techniques for PAD, diabetic foot ulcer (DFU) or tissue loss (3), the trend is in the direction of aiming for an angiosomal-targeted revascularization whenever possible (4). In revascularization procedures according to the angiosomal model, completing direct or indirect revascularization depends on if the procedure addresses the source artery that supplies blood to the area of tissue loss. Direct revascularization is achieved when the source artery is addressed, whereas indirect revascularization does not achieve this (5, 6).
Image supplied by Unsplash showing a darkened surgical room.
Vascular Case Examples with SnapshotNIR
Dr. Craig Walker, MD, Chairman New Cardiovascular Horizons, Clinical Professor of Medicine, Tulane University School of Medicine, New Orleans, LA has noted that SnapshotNIR can be specifically used in situations such as:
Timing of procedures – using Snapshot to determine if there is adequate oxygen to the area that will be operated on, otherwise, the intervention can be delayed to optimize the patient.
Post-intervention – measure StO2 immediately after an operation to help determine if the revascularization procedure chosen has done it’s expected job.
Post-intervention – ongoing monitoring of the patient to ensure continued adequate oxygenation to the wound for full healing.
Case example 1 - Timing of revascularization procedure
This patient required an immediate revascularization procedure for limb preservation. On assessment using SnapshotNIR and Arterial Doppler, the Anterior Tibial Artery was occluded. Seen in the images, pre-intervention, the dorsal foot did not have adequate oxygen supply as compared to the post-intervention image where oxygenated hemoglobin can be seen across the dorsum of the foot.
Patient images courtesy of Dr. Bryan Fisher, MD.
Case example 2 - Measuring immediate post-intervention effectiveness
Using SnapshotNIR, the clinician was able to confirm that the revascularization procedure on this patient was successful. Just 3 hours after revascularization, the patient was demonstrating an increase in oxygenation.
The three distal markers (further down the ankle) indicate an increase of 5% (from an average of 61% to 64%), and the two proximal markers (further up the ankle) increasing by 7% (from an average of 41% to 48%), with the expectation that the StO2 will continue to improve over the next few weeks.
Patient images courtesy of Dr. Jason Lindsey. Pre-revascularization.
Patient images courtesy of Dr. Jason Lindsey. 3 hours post-revascularization.
Case example 3 – Ongoing patient monitoring for chronic wound healing
A patient presented with lower limb ischemia and a non-healing chronic wound. On assessment, the patient’s occluded arteries included the Posterior Tibialis Artery (PTA), the Anterior Tibialis Artery (ATA), and the Popliteal Artery (PA).
Pre-intervention images from SnapshotNIR were used to confirm occlusion of the three source arteries. NIRS imaging of the patient’s left lower leg and foot pre- and post-intervention. Images pre-intervention confirmed the patient had occluded arteries and would be a candidate for revascularization of the popliteal artery. The lateral medial ankle had an average of 58% StO2, and plantar foot StO2 average of 61.5%.
Patient case images courtesy of Dr. Vincent Sollecito. Pre-intervention.
This patient underwent revascularization of the source artery, the PA, to the three main lower limb angiosomes for a successful outcome. Ongoing monitoring with SnapshotNIR captured these post-intervention images one-month after popliteal artery revascularization. The StO2 images color clearly shows improvement within all affected angiosomes. The lateral medial ankle StO2 average increased by 20 points to 78%, and plantar foot average increased by to 13.5 points to 75%.
Patient case images courtesy of Dr. Vincent Sollecito. Post-intervention.
Using objective data in your clinical practice for revascularization
If vascular conditions are caught in time, surgical planning can be expedited. Surgeons can open macro or micro blood vessels to reestablish blood flow. Early intervention often leads to better healing outcomes for acute and chronic wounds, reducing the chance of an amputation, and improving patient outcomes. A simple ‘Snapshot’ can potentially lead to a much higher quality and quantity of life for the patient.
“Many times, a vascular surgeon or invasive cardiologist will open the blood vessel to supply the wound area. SnapshotNIR can be used to determine if the wound area blood supply has improved. Based on this information, we can determine if further vascular intervention is needed.”
- Dr. Jonathan Arnold, MD, ABPM-UHM, CWS-P
References:
1. Kabir MH, Khan AM, Hasan MA, Chy AR, Idris R, Ahmad J. Revascularization in diabetic foot ulcer and outcome. Instruction to Authors. 2022;2022(3rd):30.
2. Heiss C, Olinic DM, Belch JJ, Brodmann M, Mazzolai L, Stanek A, Madaric J, Krentz A, Schlager O, Lichtenberg M, Frank U. Management of chronic peripheral artery disease patients with indication for endovascular revascularization. Vasa. 2022 Apr 14.
3. Chuter, V., Schaper, N., Mills, J., Hinchliffe, R., Russell, D., Azuma, N., Behrendt, C.A., Boyko, E.J., Conte, M.S., Humphries, M.D. and Kirksey, L., 2023. Effectiveness of revascularisation for the ulcerated foot in patients with diabetes and peripheral artery disease: A systematic review. Diabetes/metabolism research and reviews, p.e3700.
4. van den Berg, J.C., 2018, June. Angiosome perfusion of the foot: An old theory or a new issue?. In Seminars in vascular surgery (Vol. 31, No. 2-4, pp. 56-65). WB Saunders.
5. Stimpson, A.L., Dilaver, N., Bosanquet, D.C., Ambler, G.K. and Twine, C.P., 2019. Angiosome specific revascularisation: does the evidence support it?. European Journal of Vascular and Endovascular Surgery, 57(2), pp.311-317.
6. Tange, F.P., Ferrari, B.R., van den Hoven, P., van Schaik, J., Schepers, A., van Rijswijk, C.S., van der Meer, R.W., Putter, H., Vahrmeijer, A.L., Hamming, J.F. and van der Vorst, J.R., 2023. Evaluation of the Angiosome Concept Using Near-Infrared Fluorescence Imaging with Indocyanine Green. Annals of Vascular Surgery, 93, pp.283-290.