Multispectral Near-Infrared Spectroscopy (Nirs) Identifies Peripheral Arterial Disease (Pad) That Ankle-Brachial Index (Abi) Can Miss
First-to-Podium research presented at HMP Global’s 2026 Symposium on Advanced Wound Care (SAWC) Fall
Key Findings:
- ABI failed to identify peripheral arterial disease (PAD) in 5 of 14 PAD-positive limbs, representing a 36% failure rate
- NIRS tissue oxygenation measurements remained reduced in PAD-positive limbs even when ABI was falsely normal or uninterpretable due to noncompressible readings
- NIRS provided non-invasive tissue perfusion measurements in all study participants, supporting its potential as a complementary assessment when pressure-based testing is limited
A new study presented today during the First-to-Podium program at the 2026 Symposium on Advanced Wound Care (SAWC) Fall suggests that near-infrared spectroscopy (NIRS) tissue oxygenation imaging could help address an important limitation of conventional vascular assessment in patients with peripheral arterial disease (PAD). The findings were presented by Alisha Oropallo, MD, PhD, FACS, FSVS, FABWMS, Director of the Comprehensive Wound Healing Center at Northwell Health. Using ankle-brachial index (ABI), researchers failed to identify PAD in more than one-third of limbs with confirmed disease, while NIRS consistently detected tissue oxygenation deficits in these limbs. The findings highlight the potential value of directly assessing tissue perfusion when arterial calcification makes traditional pressure measurements unreliable.
ABI is widely used as a first-line test for PAD because it compares blood pressure at the ankle with blood pressure in the arm. However, calcification can make lower-extremity arteries difficult to compress, potentially producing falsely elevated or uninterpretable measurements. This problem is particularly relevant in patients with diabetes and chronic kidney disease, populations that are also at increased risk for vascular disease and chronic wounds.
Challenging the Standard Vascular Screening Framework
Researchers evaluated 30 adults (77% presenting with active wounds) using multispectral NIRS imaging of the dorsal, medial, and plantar surfaces of the foot, and utilizing the palmar forearm as a systemic reference. The MIMOSA PRO manufactured by MIMOSA Diagnostics Inc. (Toronto, ON, Canada) was used to non-invasively measure microvascular tissue oxygen saturation (StO₂). Participants also underwent standard vascular testing using Doppler waveforms, ABI, and toe-brachial index (TBI) when available.
The study found that ABI did not identify disease in five of 14 PAD-positive limbs. This represented a 36% failure rate consisting of two limbs with falsely normal ABI measurements, while three limbs had non-compressible arteries that prevented meaningful ABI interpretation.
NIRS measurements showed lower tissue oxygenation in the PAD group compared with controls. Mean plantar StO₂ was 73.4% in PAD-positive limbs compared with 80.0% in controls, while mean medial foot StO₂ was 68.6% versus 73.5%, respectively. Importantly, the five PAD-positive limbs in which ABI was falsely normal or non-compressible had a mean plantar StO₂ of 73.5%, similar to the PAD group overall.
Patient vascular assessment should be driven by microvascular tissue perfusion rather than misleading pressure tests
The findings suggest that tissue oxygenation imaging could provide complementary physiological information when pressure-based measurements do not adequately reflect lower-extremity perfusion. Unlike ABI, NIRS measures microvascular oxygenation directly and does not depend on arterial compressibility.
These early results support further investigation of NIRS as part of vascular and wound-care assessment, particularly in patients for whom ABI results are normal despite clinical concern or cannot be interpreted because of arterial calcification. Future research will examine whether angiosome-level StO₂ mapping can identify perfusion patterns associated with individual arterial territories and compare NIRS measurements with other established methods for measuring tissue oxygenation.
About SAWC Fall
The Symposium on Advanced Wound Care (SAWC) Fall brings the multidisciplinary wound care team together each year in Las Vegas. Held since 2009, SAWC Fall is part of HMP Global’s flagship wound care franchise, which has convened the field since 1988. The 2026 meeting, October 15–18, draws physicians, surgeons, nurses, advanced practice providers, podiatrists, physical therapists, dietitians and researchers from all 50 states and 20 countries. The program pairs the latest evidence with hands-on workshops and case-based discussion on the developments reshaping the field, from AI-driven diagnostics and advanced wound imaging to biologic therapies, mobile care delivery and vascular approaches to limb salvage, while 139 exhibiting companies bring new technologies to the exhibit hall. Learn more at hmpglobalevents.com/sawcfall.
About HMP Global
HMP Global is the trusted leader in healthcare events, education and omnichannel engagement, with a mission to improve patient care by bringing the healthcare community together. For more than 40 years, the company has built trusted brands that healthcare professionals rely on throughout their careers, including Psych Congress, the nation’s leading conference on practical psychopharmacology; the Symposium on Advanced Wound Care (SAWC), the world’s largest wound care meeting; EMS World Expo; NEI; LINC; and Advances in IBD. Today, HMP Global’s portfolio includes 27 brands and 83 events that connect more than 2 million healthcare professionals with more than 6,000 leading experts through live experiences, accredited education, year-round engagement through HMP Collective, and first-party clinician intelligence powered by Viia, creating one of the largest healthcare engagement ecosystems. Learn more at hmpglobal.com or follow the company on LinkedIn.
