Correlation between the infrared thermogram and microvascular abnormalities of the nailfold in patients with systemic sclerosis

Further insight into systemic sclerosis from the vasculopathy perspective

Systemic sclerosis (SSc) is an autoimmune disease characterized by immune dysfunction, vascular system dysfunction, and tissue fibrosis. Vascular injury, vascular remodeling, and endothelial dysfunction are the hallmark pathological changes of the disease. In the early stages of SSc development, endothelial cell injury and apoptosis can lead to vascular and perivascular inflammation, oxidative stress, and tissue hypoxia, which can cause clinical manifestations in various organs from the skin to the parenchymal organs. Early diagnosis and rational treatment can improve patient survival and quality of life. Ancillary examinations such as nailfold capillaroscopy as well as optical coherence tomography can help early detect vascular injury in SSc patients. Studies targeting the mechanisms of vascular lesions will provide new perspectives for treatment of SSc.

Clinical assessment of patients with systemic sclerosis: is there a place for thermography?

Recurrent changes of temperature and persistence of cooling along fingers at the room temperature make hands the most frequent region of interest for thermography in systemic sclerosis (SSc). The aim of this study was to evaluate dependance of temperature in hands on a subtype of the disease, immune profile of antinuclear antibodies (ANA), and lung involvement. There were 29 patients with limited cutaneous involvement (lcSSc) and 10 patients with diffuse cutaneous disease (dcSSc) enrolled for the study. To compare measurements to normal values, there were enrolled 29 healthy volunteers (control group). All participants were submitted to thermography with handheld camera FLIR One Pro for iOS, attached to mobile phone iPhone 11, at the fixed temperature of 21 °C. Measurements included average temperature (T_avg) over nailfolds in thumbs and fingers II-V, as well as the difference in average temperatures (TΔ) between metacarpus of the hand and its thumb and fingers II-V. Both thumbs and fingers II-V remained cooler in subjects with dcSSc compared to those with lcSSc. This implicated a significantly greater TΔ along thumbs and fingers II-V in dcSSc group. Although T_avg at nailfolds in SSc patients was not lower than in healthy controls, TΔ remained significantly more pronounced in both lcSSc and dcSSc subjects. A positivity to ACA in lcSSc group was found to be associated with significantly lower T_avg and more pronounced TΔ in fingers II-V than the presence of anti-Scl70 antibodies. Temperature measurements remained statistically independent on a presence of ILD in lcSSc group, but both thumbs and fingers II-V in dcSSc group were warmer in case of lung involvement. The study showed the dcSSc subtype, the positivity of ACA in lcSSc, but not lung involvement were associated with poorer thermal control in the hands of SSc patients. A comparison to healthy controls highlighted the weakness of temperature measurements at nailfolds (T_avg) but increased the value of TΔ in thermography of hands.

Correlation between Microvascular Damage and Internal Organ Involvement in Scleroderma: Focus on Lung Damage and Endothelial Dysfunction

BACKGROUND

Systemic sclerosis (SSc) is an incurable connective tissue disease characterized by decreased peripheral blood perfusion due to microvascular damage and skin thickening/hardening. The microcirculation deficit is typically secondary to structural vessel damage, which can be assessed morphologically and functionally in a variety of ways, exploiting different technologies.

OBJECTIVE

This paper focuses on reviewing new studies regarding the correlation between microvascular damage, endothelial dysfunction, and internal organ involvement, particularly pulmonary changes in SSc.

METHODS

We critically reviewed the most recent literature on the correlation between blood perfusion and organ involvement.

RESULTS

Many papers have demonstrated the link between structural microcirculatory damage and pulmonary involvement; however, studies that have investigated correlations between microvascular functional impairment and internal organ damage are scarce. Overall, the literature supports the correlation between organ involvement and functional microcirculatory impairment in SSc patients.

CONCLUSIONS

Morphological and functional techniques appear to be emerging biomarkers in SSc, but obviously need further investigation.

Imaging techniques for assessment of vascular involvement in systemic sclerosis

PURPOSE OF REVIEW

Vascular assessment in systemic sclerosis (SSc) is included in classification criteria for this disease, thus routinely used in the evaluation of patients in which this diagnosis is being considered. In this review, imaging techniques for assessment of vascular involvement in SSc hands and skin are discussed.

RECENT FINDINGS

Longitudinal use of imaging techniques has important implications for understanding the progressive vasculopathy and fibrotic transition in SSc. Nailfold and oral capillaroscopy as well as laser speckle contrast analysis are established techniques for vascular functional assessment, but longitudinal use is challenged by equipment costs and clinical time constraints. Ultrasound techniques are well described but require technical training. Advances in mobile infrared thermography and optical coherence tomography could potentially provide a point-of-care, quantitative outcome measure in clinical trials and practice.

SUMMARY

The equipment cost, technical training, data standardization, and invasiveness of vascular assessment techniques that quantify morphological (microangiopathy) and functional (blood flow reduction) are critical for implementation into SSc clinical trials and practice to understand progressive vasculopathy, such as wound development.