The Impact of Diabetes in Intermittent Claudication: A Prospective Cohort Study.

The aim of this study was to determine the lower-limb outcome in patients with intermittent claudication (IC) and to identify predictors for deterioration. This study employed a prospective observational cohort single-centre design. One hundred fifty patients with IC attending a vascular surgery unit for the first time were recruited. Lower limb perfusion was assessed utilising ankle brachial index (ABI) measures, toe-brachial index (TBI) measures, Doppler waveform analysis and the walking impairment questionnaire. Follow-up was conducted after 1 year and 2 years following recruitment to assess haemodynamic parameters, symptom severity and outcome. Recruited participants had a mean age of 69.7 (±9.3) years, BMI 27.8(±4.2) and 79.3% were men. Significant haemodynamic decline (decline in ABPI by ≥0.15 and/or decline in TBPI by ≥0.1) occurred in 50.6% of the cohort within 2 years of whom 23.3% developed chronic limb threatening ischaemia (CLTI) with rest pain and/or tissue loss. Baseline ABPI, ABPI ≤ 0.5, TBPI ≤ 0.39, infrapopliteal artery (IPA) disease and high Haemoglobin A1c were identified as significant predictors for deterioration to CLI. (P < .05, binomial logistic regression). Patients with IC are at a high risk of developing CLTI within 2 years. Risk of lower limb adverse events is tripled in patients with IPA disease, low ankle and toe pressures and poorly controlled diabetes. Early identification of those at high risk for early deterioration may justify a paradigm shift in the management of this subgroup.

The Effects of Skin Temperature Changes on the Integrity of Skin Tissue: A Systematic Review.

OBJECTIVE: To determine whether changes in skin temperature can affect the integrity of skin. METHODOLOGY: The authors conducted a systematic literature search as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. They searched the CINAHL (Cumulative Index to Nursing and Allied Health Literature), Cochrane, MEDLINE Complete, Academic Search Ultimate, and HyDi databases for articles examining the effects of skin temperature on skin integrity published through April 2020. Two independent reviewers scored the methodologic quality of the 13 included studies. RESULTS: Only 11 studies were included in the qualitative analysis, as the other two articles had a critical risk of bias. There is strong evidence to indicate that an increase in skin temperature leads to changes in skin structure and function. However, ulcer formation was more affected by intrinsic and extrinsic factors, rather than by temperature alone. CONCLUSION: Further high-quality randomized controlled trials are required to investigate the direct effect of skin temperature on ulceration.

Thermographic Characteristics of the Diabetic Foot With Peripheral Arterial Disease Using the Angiosome Concept.

AIM: To compare temperature changes following a challenge of limb elevation, in 3 forefoot angiosomes between type 2 diabetes mellitus patients with and without peripheral arterial disease (PAD). METHODS: Participans were categorized in a no PAD, mild PAD or severe PAD group. All underwent thermal imaging, then successive thermal images were taken at 1 min intervals after the lower limbs were elevated for 5 min. Thereafter, the lower limbs were lowered to the original position and imaged after 1 min. Mean temperatures of the hallux, medial and lateral forefoot were analysed by the angiosome concept. RESULTS: Forty-two limbs were analysed. Mean resting temperatures of all angiosomes of participants with PAD were higher than those with no peripheral arterial disease. A significant difference in the mean initial temperature between the groups was found in the medial and lateral forefoot angiosomes (p=0.048, p=0.049 respectively), whilst at the hallux these temperatures were not significant (p=0.165). After limb elevation, the only significant difference was seen in the lateral foot area at 1 min (p=0.021). CONCLUSIONS: These results confirm that patients with PAD exhibit significantly higher forefoot temperatures, according to the angiosome concept. The challenge by foot elevation did not affect the thermal pattern significantly.

Interrater Reliability of Spectral Doppler Waveform Analysis Among Podiatric Clinicians.

BACKGROUND: Spectral Doppler ultrasound examination of pedal arteries is one of the most frequently used noninvasive assessment methods by health-care professionals for the diagnosis and ongoing monitoring of people at risk for or living with peripheral arterial disease. The aim of this study was to determine the interrater reliability of the interpretation of spectral Doppler waveform analysis. METHODS: An interrater reliability study was conducted among five experienced podiatric physicians at the University of Malta Research Laboratory (Msida, Malta). A researcher who was not a rater in this study randomly selected 229 printed spectral Doppler waveforms from a database held at the University of Malta. Each rater independently rated the qualitative spectral waveforms. RESULTS: Interrater reliability of the spectral Doppler waveform interpretation was excellent among the five experienced podiatric physicians (α = 0.98). The intraclass correlation coefficient showed a high degree of correlation in waveform interpretation across raters ( P < .001). CONCLUSIONS: This study demonstrates high interrater reliability in visual spectral Doppler interpretation among experienced clinicians. The current foot screening guidelines do not refer to spectral Doppler waveform analysis in their recommendations, which has been shown in studies to be an important modality for the diagnosis of peripheral arterial disease when ankle-brachial pressure indexes are falsely elevated in calcified arteries. If interpreted correctly, the information obtained can provide an indication of the presence of peripheral arterial disease and facilitate early management of this condition.

The Application of Medical Thermography to Discriminate Neuroischemic Toe Ulceration in the Diabetic Foot.

This study aimed to determine whether thermal imaging can detect temperature differences between healthy feet, nonulcerated neuroischemic feet, and neuroischemic feet with toe ulcers in patients with type 2 diabetes mellitus (T2DM). Participants were prospectively divided into 3 groups: T2DM without foot problems; a healthy, nonulcerated neuroischemic group, and an ulcerated neuroischemic group. Thermal images of the feet were obtained with automated segmentation of regions of interest. Thermographic images from 43 neuroischemic feet, 21 healthy feet, and 12 neuroischemic feet with active ulcer in one of the toes were analyzed. There was a significant difference in toe temperatures between the 3 groups ( P = .001), that is, nonulcerated neuroischemic (n = 181; mean temperature = 27.7°C [±2.16 SD]) versus neuroischemic ulcerated (n = 12; mean temperature = 28.7°C [±3.23 SD]), and healthy T2DM group (n = 104; mean temperature = 24.9°C [±5.04 SD]). A post hoc analysis showed a significant difference in toe temperatures between neuroischemic nonulcerated and healthy T2DM groups ( P = .001), neuroischemic ulcerated and healthy groups ( P = .001). However, no significant differences in toe temperatures were identified between the ulcerated neuroischemic and nonulcerated neuroischemic groups ( P = .626). There were no significant differences between the ulcerated toes (n = 12) and the nonulcerated toes (n = 57) of the same foot in the ulcerated neuroischemic group ( P = .331). Toe temperatures were significantly higher in neuroischemic feet with or without ulceration compared with healthy feet in patients with T2DM. There were no significant differences in temperatures of ulcerated toes and the nonulcerated toes of the same foot, implying that all the toes of the same foot could potentially be at risk of developing complications, which can be potentially detected by infrared thermography.

Establishing Differences in Thermographic Patterns between the Various Complications in Diabetic Foot Disease.

AIM: To evaluate the potential of thermography as an assessment tool for the detection of foot complications by understanding the variations in temperature that occur in type 2 diabetes mellitus (DM). METHODS: Participants were categorized according to a medical examination, ankle brachial index, doppler waveform analysis, and 10-gram monofilament testing into five groups: healthy adult, DM with no complications, DM with peripheral neuropathy, DM with neuroischaemia, and DM with peripheral arterial disease (PAD) groups. Thermographic imaging of the toes and forefeet was performed. RESULTS: 43 neuroischaemic feet, 41 neuropathic feet, 58 PAD feet, 21 DM feet without complications, and 126 healthy feet were analyzed. The temperatures of the feet and toes were significantly higher in the complications group when compared to the healthy adult and DM healthy groups. The higher the temperatures of the foot in DM, the higher the probability that it is affected by neuropathy, neuroischaemia, or PAD. CONCLUSIONS: Significant differences in mean temperatures exist between participants who were healthy and those with DM with no known complications when compared to participants with neuroischaemia, neuropathy, or PAD. As foot temperature rises, so does the probability of the presence of complications of neuropathy, neuroischaemia, or peripheral arterial disease.

The identification of higher forefoot temperatures associated with peripheral arterial disease in type 2 diabetes mellitus as detected by thermography.

AIMS: The purpose of this study was to investigate whether heat emitted from the feet of patients with type 2 diabetes (DM) and peripheral arterial disease (PAD) differed from those with type 2 diabetes without complications (DM). METHODS: A non-experimental, comparative prospective study design was employed in a tertiary referral hospital. Out of 223 randomly selected participants (430 limbs) who were initially tested, 62 limbs were categorized as DM+PAD and 22 limbs as DM without PAD. Subjects with evidence of peripheral neuropathy were excluded. Participants underwent thermographic imaging. Automatic segmentation of regions of interest extracted the temperature data. RESULTS: A significant difference in temperature in all the toes between the two groups was found (p=0.005, p=0.033, p=0.015, p=0.038 and p=0.02 for toes 1-5 respectively). The mean forefoot temperature in DM+PAD was significantly higher than that in DM (p=.019), with DM+PAD having a higher mean temperature (28.3°C) compared to DM (26.2°C). Similarly, the toes of subjects with DM+PAD were significantly warmer than those of subjects with DM only. CONCLUSIONS: Contrary to expectations the mean toe and forefoot temperatures in DM patients with PAD is higher than in those with DM only. This unexpected result could be attributed to disruption of noradrenergic vasoconstrictor thermoregulatory mechanisms with resulting increased flow through cutaneous vessels and subsequent increased heat emissivity. These results demonstrate that thermography may have potential in detecting PAD and associated temperature differences.

Automated Region Extraction from Thermal Images for Peripheral Vascular Disease Monitoring.

This work develops a method for automatically extracting temperature data from prespecified anatomical regions of interest from thermal images of human hands, feet, and shins for the monitoring of peripheral arterial disease in diabetic patients. Binarisation, morphological operations, and geometric transformations are applied in cascade to automatically extract the required data from 44 predefined regions of interest. The implemented algorithms for region extraction were tested on data from 395 participants. A correct extraction in around 90% of the images was achieved. The process of automatically extracting 44 regions of interest was performed in a total computation time of approximately 1 minute, a substantial improvement over 10 minutes it took for a corresponding manual extraction of the regions by a trained individual. Interrater reliability tests showed that the automatically extracted ROIs are similar to those extracted by humans with minimal temperature difference. This set of algorithms provides a sufficiently accurate and reliable method for temperature extraction from thermal images at par with human raters with a tenfold reduction in time requirement. The automated process may replace the manual human extraction, leading to a faster process, making it feasible to carry out large-scale studies and to increase the regions of interest with minimal cost. The code for the developed algorithms, to extract the 44 ROIs from thermal images of hands, feet, and shins, has been made available online in the form of MATLAB functions and can be accessed from http://www.um.edu.mt/cbc/tipmid.

Automated segmentation of regions of interest from thermal images of hands.

Thermal imaging can provide an image of the surface temperature of an object in a non-contact and noninvasive manner, making it particularly appealing for use in medical applications. In applications where it is desirable to extract temperature data from anatomical regions of interest (ROIs) in a standardised and consistent manner, the use of automated segmentation and analysis techniques can provide a faster, more reliable and more consistent approach than manual segmentation of these ROIs. In this paper we present an algorithm which automatically extracts temperature data from eight ROIs in thermal images of the volar aspect of human hands. The algorithm first identifies the hand from the background in the thermal image and then identifies pixels which make up the fingers and the palm. Finally, eight ROIs are extracted from the identified regions. The methods proposed in this work can also be extended for the processing of similar visual images.

Thermographic patterns of the upper and lower limbs: baseline data.

Objectives. To collect normative baseline data and identify any significant differences between hand and foot thermographic distribution patterns in a healthy adult population. Design. A single-centre, randomized, prospective study. Methods. Thermographic data was acquired using a FLIR camera for the data acquisition of both plantar and dorsal aspects of the feet, volar aspects of the hands, and anterior aspects of the lower limbs under controlled climate conditions. Results. There is general symmetry in skin temperature between the same regions in contralateral limbs, in terms of both magnitude and pattern. There was also minimal intersubject temperature variation with a consistent temperature pattern in toes and fingers. The thumb is the warmest digit with the temperature falling gradually between the 2nd and the 5th fingers. The big toe and the 5th toe are the warmest digits with the 2nd to the 4th toes being cooler. Conclusion. Measurement of skin temperature of the limbs using a thermal camera is feasible and reproducible. Temperature patterns in fingers and toes are consistent with similar temperatures in contralateral limbs in healthy subjects. This study provides the basis for further research to assess the clinical usefulness of thermography in the diagnosis of vascular insufficiency.

Hidden dangers revealed by misdiagnosed peripheral arterial disease using ABPI measurement.

AIM: The aim of this study was to compare ankle brachial indices (APBI) with pedal waveforms utilizing the continuous wave Doppler in a population with diabetes mellitus. METHODS: A prospective study design was employed to investigate the ABPI in a cohort of 49 people with type 2 diabetes mellitus. ABPI assessment was completed using a portable handheld Doppler and ankle pressures of <0.9 were taken as suggestive of peripheral arterial disease (PAD). Arterial spectral waveforms in each foot were also recorded and compared to the ABPI readings. RESULTS: Inconsistencies were identified between ABPIs and waveform interpretations in the study population. Approximately 35% of subjects had inconsistencies between their ABPI result and waveform interpretation in their right or left foot. CONCLUSIONS: Both ABPIs and Doppler waveforms should be used in the assessment of people with diabetes in order to screen for PAD. This would ensure an accurate assessment of PAD and would allow initiation of appropriate secondary risk factor control measures.