Infrared thermography in the assessment of peripheral arterial disease
Julia F. Chen, MD1, Jennifer Bloom1, Han Saem Rue1, Cassius Iyad Ochoa Chaar, MD1, Kristine Orion, MD1, Timur Sarac, MD2, Jonathan Cardella, MD1.
1Yale New Haven Hospital, New Haven, CT, USA, 2Ohio State University, Columbus, OH, USA.
OBJECTIVES: The purpose of this study is to determine whether lower limb temperatures obtained via infrared thermography (IT) can be used as an adjunct in the evaluation of peripheral arterial disease (PAD).METHODS: All patients who underwent ABI/PVR (ankle-brachial index with pulse volume recording) and TBI (toe-brachial index) within 30 days of their outpatient clinical assessment were invited to participate in this study. Participants had thermal images taken of their extremity using the FLIR ONE Gen 3 camera (FLIR Systems; Wilsonville, OR) for iOS (Apple; Cupertino, CA). Temperature points were recorded in the ankles, feet and toes. Patients with severe peripheral arterial disease (sPAD) were defined as those with TBI<0.5, ABI<0.5, or chronic critical limb ischemia (regardless of ABI or TBI). Statistical analysis was performed using Stata 15 (StataCorp; College Station, TX). RESULTS: 76 patients (43% female, average 66.3 years old) and 142 distinct lower limbs were evaluated (51.7% diabetic; 36.6% sPAD). In all patients, mean temperatures were 33.1±2.1, 32.6±2.6 and 29.2±3.4 degrees Celsius in the ankle, foot and toes respectively (p<0.001). Diabetics with sPAD had higher temperatures than non-diabetic sPAD patients at the ankle (33.9 vs 32.6 degrees, P=0.01), foot (33.8 vs 30.9, p<0.001) and toes (31.6 vs 27.1, P=0.02). Furthermore, diabetics with sPAD had higher temperatures when compared to diabetics without sPAD at the ankle (33.9 vs. 33.0, p=0.06), foot (33.8 vs. 32.6, p=0.03), and toes (31.6 vs. 29.6, p=0.09). Conversely, non-diabetics with sPAD exhibited lower temperatures at the foot when compared to non-diabetics without sPAD (32.3 vs 30.9, p=0.08). (Table) CONCLUSIONS: Temperature decreases significantly from the ankle to toe. Foot temperature varies based on PAD status, as well as diabetic status. Among patients with sPAD, those with diabetes had higher temperatures than those without. Among diabetics, those with sPAD had higher temperatures than those without sPAD. Conversely, non-diabetics with sPAD exhibited lower foot temperatures than those without sPAD. This study shows that diabetics have a different pattern of thermal change versus non-diabetics. Further studies will help define the mechanism of change and may alter therapy in this cohort. 
Back to 2019 ePosters