Infrared Thermography as a Diagnostic Tool for the Assessment of Patients with Symptomatic Peripheral Arterial Disease Undergoing Infrafemoral Endovascular Revascularisations

Abstract

Aim: The aim of this study was to evaluate the utility and reliability of temperature foot changes measured by infrared thermography (IRT) for the evaluation of patients with atherosclerotic peripheral arterial disease (PAD) before and after endovascular revascularisation. Methods: This is an observational prospective study carried out on symptomatic PAD patients. Evaluations consisted of a clinical examination, duplex scan with ankle–brachial index calculation (ABI) and IRT measurements with infrared camera FLIR-ONE connected to a smartphone with android technology. Locations on the foot sampled with IRT were the anterior tibial, pedal, posterior and arcuate arteries. Results obtained with IRT on the symptomatic foot were compared to the contralateral foot and with the ABI values obtained bilaterally before and 24 h after revascularisation. Results: Within one year, 40 patients were enrolled, among whom 87,5% suffered from critical limb ischaemia. In three patients, it was impossible to obtain ABI measurements because of ulcerations on the limb. Skin temperature changes obtained by IRT between the symptomatic limb and the contralateral limb had a mean difference of 1.7 °C (range: 1.1–2.2 °C), p < 0.001. There was a positive correlation between ABI and temperature values of the limb needed for treatment before revascularisation (p = 0.025; r = 0.36) and after revascularisation (p = 0.024, r = 0.31). The technical success rate was 100% in all cases, achieving a significant increase in temperature at all points of the foot analysed, with a median change of 2 °C (p < 0.001). Conclusion: IRT is a safe, reliable and simple application. It could be a valuable tool for the assessment of the clinical presentation and severity of foot blood perfusion in symptomatic PAD patients and the evaluation of the technical success of endovascular revascularisation. IRT might have a role in follow-up of revascularisation procedures.

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 .…”

“…Five studies have monitored the effect of revascularization procedures using IRT [ 33 , 34 , 35 , 39 , 49 ]. Zenunaj et al [ 39 ] evaluated the effectiveness of an intervention by measuring the temperature in both feet before and 24 h after the surgery, observing an improvement of +2.1 °C and +0.5 °C in the limb that underwent the revascularization.…”

“…Five studies have monitored the effect of revascularization procedures using IRT [ 33 , 34 , 35 , 39 , 49 ]. Zenunaj et al [ 39 ] evaluated the effectiveness of an intervention by measuring the temperature in both feet before and 24 h after the surgery, observing an improvement of +2.1 °C and +0.5 °C in the limb that underwent the revascularization. Similarly, the article of Staffa et al [ 34 ] evaluated IRT as a supplementary method in assessing the treatment effect of percutaneous transluminal angioplasty by obtaining thermal images before and after the surgery.…”

“…The systematic review included studies that employed IRT in patients with PAD as both diagnostic methods, or as an outcome for measuring the success of an interventional procedure. At first, IRT demonstrated its versatility, being employed in studies enrolling PAD patients at any disease stage and being exposed to different procedures, including revascularization [ 33 , 34 , 35 , 39 , 49 ], pharmacological [ 43 , 45 ] or physical [ 36 , 38 ].…”

“…In relation to the twenty-one included studies, the majority of them ( n = 13) had a relatively small sample size (less than 50 patients), while the remaining eight recruited a significant number of participants (from 51 to 217). In addition, the studies enrolled patients with a wide heterogeneity of age, from relatively young age patients (mean age < 40 years old [ 47 ] to older patients (mean age > 75 years [ 39 ]), making it difficult to summarize the data collected.…”