Digital laser doppler flowmetry may discriminate “limited” from “diffuse” 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.

Nailfold capillaroscopy : a comprehensive review on common findings and clinical usefulness in non-rheumatic disease

Nailfold video-capillaroscopy (NVC) is a useful diagnostic tool, used to early detect abnormalities in micro-circulation, providing a qualitative description of microvascular anomalies in Raynaud's phenomenon. NVC role in the diagnosis of Systemic Sclerosis is well known. In other rheumatic conditions such as connective tissue diseases, vasculitis, and arthritis, the NVC anomalies are often included in a scleroderma like pattern. The use of NVC in non-rheumatic diseases (NRD), with remarkable microvascular damage, as diabetes, is not standardized yet, although several research studies are carrying on. The aim of this article is to provide a resume of published results in order to lay the groundwork for the employment of NVC both in the diagnosis and follow up of microvascular complication in NRD. Furthermore, we mention NVC findings in pathologies without well recognize microvascular damages in their pathogenesis : micro-vessels abnormalities may suggest a different point of view. J. Med. Invest. 68 : 6-14, February, 2021.

Assessing recovery after cold challenge and thumb involvement can help to rule out systemic sclerosis in patients presenting with Raynaud's phenomenon

Objective: Our aim was to study whether recovery from a Raynaud's attack and involvement of the thumb are differentiators for systemic sclerosis (SSc) in patients with Raynaud's phenomenon (RP).Method: A stepwise cooling and recovery procedure was performed, provoking an RP attack, in patients with primary Raynaud's phenomenon (PRP, n = 68) and SSc (n = 18). During the procedure, the perfusion of all five fingers during cooling and recovery was assessed by photoelectric plethysmography.Results: In SSc patients, perfusion after 10 min in one or more fingers was more frequently not restored than in PRP patients (p = 0.001), with a negative predictive value of 98%. The thumb was more frequently involved in SSc patients (p = 0.036), with a negative predictive value of 95%. Positive predictive values were low.Conclusions: In patients with RP, when there is restoration of perfusion in all fingers after 10 min or when the thumb is spared, the presence of an underlying SSc is very unlikely. Although these results need to be validated in a clinical setting in a larger prospective study, these signs can help physicians to select additional testing for SSc in RP patients.

Sample size determination in the laser-Doppler measurements of skin blood flow

Pre-study calculations of the required sample size are vital to a large majority of studies. Using the method based on the Monte-Carlo simulations, we have illustrated how the sample size is related to the statistic power value, the significance level, the variability of observations and the minor magnitude of the effect of interest under study. If the study has been already completed, one should not perform any 'post hoc' power calculations. In this case, calculation of confidence intervals is a better choice. We assessed the confidence intervals given in a number of publications where microcirculation is studied by LDF techniques using different protocols. We have found that types I and II errors are frequently encountered in the LDF studies, which is a consequence of an inappropriate sample size.

Acral coldness - severely reduced blood flow to fingers and toes

The term acral coldness is used to describe physiologic or pathologic situations in humans where the fingers and toes are exceptionally cold in spite of normal central body temperature. In the thermoneutral zone, the blood flow to acral skin normally shows large fluctuations between high and low values, with a frequency of about 3 cycles per minute. At an acral skin temperature of about 21°C, finger blood flow is constantly low. At lower temperatures the fingers and toes become painful. This is a normal physiologic reaction, probably because of ischemia. The characteristics of the most frequent acral vascular syndromes, Raynaud phenomenon, acrocyanosis, and chilblains, are discussed. Common to all three is pathologically low blood flow and disappearance of physiologic fluctuations even in the thermoneutral zone. Ischemic vascular diseases in acral skin are usually diagnosed from clinical observations. Measurements of fluctuating blood flow by laser or ultrasound Doppler could be useful, but should be carried out at a room temperature of 24-25°C.

Evidence for increase in finger blood flow, evaluated by laser Doppler flowmetry, following iloprost infusion in patients with systemic sclerosis: a week-long observational longitudinal study

OBJECTIVES

Iloprost plays an important role in the treatment of Raynaud's phenomenon (RP), but has transient vasodilatory effects owing to its very short half-time. We aimed to evaluate short- and medium-term haemodynamic effects of iloprost by measuring dorsal finger microvessel blood flow using laser Doppler flowmetry (LDF), in patients with RP associated with systemic sclerosis (SSc).

METHOD

In 24 consecutive SSc patients with RP (disease duration 10.5 ± 1.3 years), LDF with heating probes was used to measure blood flow in four fingers by occlusive and heating tests, at baseline, after 3 consecutive days of iloprost infusion, and at 24 h and 7 days after last iloprost infusion. Nailfold videocapillaroscopy (NVC) patterns of microvascular damage were investigated. Sixteen healthy controls were studied to compare baseline flows.

RESULTS

Compared to controls, SSc patients showed significantly impaired axon reflex vasoregulation and nitric oxide responses at baseline (p = 0.001 and p = 0.03, respectively). After iloprost, a prompt but transient significant improvement in endothelial-dependent vasodilation (occlusive test) was seen only in SSc patients with an 'active' NVC pattern (p ≤ 0.05). The iloprost effects vanished within 7 days after the last infusion. No significant differences were found, in the whole study, between patients with and without digital ulcers.

CONCLUSIONS

Microcirculatory blood flow increases following 3 days of iloprost infusion but fades shortly after treatment. Although iloprost is effective in reducing the severity of RP in SSc, the most suitable regimen and timing to obtain longer lasting vasodilatory benefits remain to be established.

Laser Doppler perfusion imaging in systemic sclerosis impaired response to cold stimulation involves digits and hand dorsum

OBJECTIVES

To assess by Laser Doppler perfusion imaging (LDPI) skin blood perfusion of hands in patients with SSc and primary RP (PRP) at baseline and after cold stimulation (CS). In SSc patients, the associations between skin perfusion and nailfold video capillaroscopy (NVC) patterns were also evaluated.

METHODS

Forty patients with SSc, 38 patients with PRP and 32 healthy controls were recruited. Skin blood flow of the hands was detected by Lisca Laser Doppler Perfusion Imager at baseline and after CS. Further laser Doppler scanning was performed for each hand at 0 (T(1)), 3 (T(2)), 7 (T(3)) and 15 min (T(4)).

RESULTS

Baseline mean perfusion is significantly (P < 0.000 l) lower in SSc patients than in healthy controls. In SSc patients, mean perfusion is reduced after CS (P < 0.0001) and skin flow recovery (significant difference between T(0) and T(4), P < 0.0001) is incomplete. In SSc patients with low vascular damage (early and active capillaroscopic groups), the abnormal microvascular response to CS involves only the digits, while the perfusion of hands dorsum is normal. With the progression of vascular damage (late capillaroscopic groups), the abnormal microvascular response to CS also appears in the hand dorsum skin. In PRP patients, baseline hand perfusion is very low and the skin flow recovery after CS is absent (P < 0.05).

CONCLUSION

In early SSc, the thermoregulation of finger skin is impaired, but only in advanced stages of microangiopathy does the skin of the hand dorsum show a vasomotor control failure.