(PC240) Correlation Between Infrared Pedal Temperature Measurements and Lower Extremity Non-invasive Tests in Patients with Peripheral Artery Disease Following Revascularization

Objectives: The non-invasive gold standard for distal extremity arterial flow evaluation are ankle/toe-brachial indexes (ABI/TBI) and toe pressure. These tests must be administered in the clinical setting requiring the patient to travel. Currently, there are no home-based devices that can detect early changes in arterial blood flow. External temperature measurement may serve as a screening tool to identify early signs of diminished vascular flow around wounds after a revascularization procedure. This study aimed to evaluate the correlation between Infrared Thermometer readings and TBI in patients with ischemia foot wounds post revascularization.

Methods: Patients with peripheral artery disease (PAD) who had undergone revascularization from January 2024- November 2024 were enrolled. Foot temperature was measured using the Exergen DermaTemp DT-2000-BT FootScanner™ Infrared Thermometer with Bluetooth® Technology at six locations (hallux, 1st, 3rd, 5th metatarsal, midfoot, heel) on both feet. ABI/TBI/toe pressure were obtained as per standard of care. Subjects were categorized into wounds and no-wounds with the wound side being the side of intervention. Descriptive statistics were calculated. Fisher's exact test and Student's t-test were conducted to compare both groups. Pearson correlation analysis was performed to assess the relationship between foot temperature and ABI/TBI in both groups.

Results: Thirty-three patients were analyzed (72% male) of which 39% had foot wounds. The wound group cohort had a mean age of 75 years and was predominantly male (69%) and white (92%). The wound group demonstrated significantly lower mean ABIs compared versus the no-wound group (0.65 vs. 0.71, p< 0.006) as well as reduced toe pressure (46.2 mmHg vs. 66.41 mmHg, p < 0.0001) (Table I). The wound group exhibited consistently higher mean temperatures across all six measured foot regions compared to the no-wound group (p < 0.0001) (Table II). Higher TBI was associated with lower temperatures at both the first metatarsal (R = -0.60, p = 0.02) and the third metatarsal (R = -0.66, p = 0.03) among the wound group in the right foot.

Conclusions: The wound group demonstrated lower ABI and toe pressure, and elevated foot temperatures compared to the no-wound group indicating that changes in temperature of the foot wound area may be an early sign of diminishing blood flow prompting formal clinical evaluation. Additionally, higher right mean TBIs was associated with lower temperature in 1st and 3rd metatarsal. These observations highlight the importance of investigating the potential role of vascular and thermoregulatory mechanisms in PAD.