Correlation between ankle-brachial index and thermography measurements in patients with peripheral arterial disease

Abstract

Objectives To correlate the ankle-brachial index and photographic thermography findings in patients with peripheral arterial disease. Methods Photographic thermography was performed at the foot level, and ankle-brachial index was measured in 72 lower limbs of 53 patients with peripheral arterial disease who were divided into calcified artery, patients with an ankle-brachial index greater than 1.4; and non-calcified artery classified as asymptomatic, mild, moderate, and severe on the basis of peripheral arterial disease severity. Fisher’s exact test was used for categorical data, and Wilcoxon test was used for numerical data. Results Spearman’s correlation analysis showed a strong correlation (R = 0.7) between the ankle-brachial index and the mean plantar temperature in patients without lower limb artery calcification. Linear regression yielded the predictor equation Y = 3.296 × X + 29.75, wherein ankle-brachial index (X) can be predicted on the basis of temperature values. Spearman’s correlation test showed no significance ( p = 0.2174) in patients with arterial calcification. Kruskal–Wallis test with post hoc analysis using Dunn’s test for multiple comparisons showed that the mean plantar temperature was lower in patients with arterial calcification. Conclusion Photographic thermography findings show a strong correlation with ankle-brachial index in patients with non-calcified arteries.

The Value of Infrared Thermography to Assess Foot and Limb Perfusion in Relation to Medical, Surgical, Exercise or Pharmacological Interventions in Peripheral Artery Disease: A Systematic Review

“…The included studies reported different measurement sites, focusing in particular on the feet. One study did not precisely describe the measurement location [ 45 ], 2 articles studied the ankle and the anterior tibial face [ 39 , 44 ], six the toes [ 2 , 32 , 33 , 41 , 42 , 43 , 48 ], seven the dorsum of the foot [ 31 , 32 , 37 , 38 , 39 , 46 , 49 ] and eleven authors identified the plantar side of the foot, making it the most studied area [ 22 , 32 , 33 , 34 , 35 , 36 , 40 , 42 , 44 , 50 ]. A summary of the measurement locations is reported in Figure 2 .…”

“…The study of de Carvalho Abreu et al [ 22 ] correlated IRT findings and ABI in patients with PAD and observed a strong direct correlation between IRT and ABI in patients with noncalcified arteries. Moreover, the study of Wallace et al [ 37 ] found a positive correlation, concluding that IRT is a valid method in addition to ABI to assess PAD.…”

“…Despite the heterogeneity of the population enrolled and of the data collected, all authors agreed on the utility of IRT in the monitoring of PAD patients, and particularly Carvalho Abreu et al [ 22 ] suggest preferring IRT to ABI in patients who did not appreciate the latter technique, with these two measurements strictly correlated. Although the use of IRT as a diagnostic technique is still debated, more evidence is provided when employing IRT as an outcome measure.…”

“… Example of a thermographic image with the site of the collection according to each study. References: [ 2 , 21 , 22 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. …”

“…This technique is noncontact, noninvasive, low cost, and allows a quick examination of the energy radiated by the user’s body. It is safe for both patients and health professionals and is reliable for the measurement of skin temperature [ 21 , 22 , 23 ].…”