The association between microvascular involvement, as evaluated by nailfold capillaroscopy (NC) and disease-related clinical manifestations, in patients with systemic sclerosis (scleroderma) has been recently well assessed using the current classification of scleroderma patterns (1).
As matter of fact, the “late” scleroderma pattern is the strongest related to severe skin or visceral involvement and to the risk for digital ulcers, as well as the development of ischemic lesions (2). However, although in SSc the microangiopathy observed by NC has been related with the severity of skin, heart and lung involvement, the majority of reports focused on peripheral ischemia and in particular on digital ulcers (DUs) (3).
It has been shown that the degree of capillary abnormalities may predict the development of digital ulcers. For example, an early index (CSURI) can be calculated by measuring the maximum loop diameter (D), and by counting the total number of capillaries (squared number) in the distal row (N) and the number of mega capillaries (M) (CSURI = D x M:N2) (4). Unfortunately, a very strong limitation of this index is the mandatory presence of mega capillaries, so excluding patients with a “late” pattern exactly when the risk of DUs is at the hishest risk.
On the other hands, a reliable and simple prediction index has been constructed by analysing the mean score of loss of capillaries quantified over eight fingers (one field per finger) (5). This is a day-to-day (DTD index) method to predict the development of digital trophic lesions within 6 or 12 months period has now been also validated by a large pan-european multi-center study (CAP study) (6). The CAP multicenter observational, longitudinal prospective study was conducted in SSc patients with or without history of DU. The results showed that in SSc patients with a past history of DUs the reduced mean number of capillaries in the middle finger of the dominant hand, together with increased number of current DUs and the presence of current critical digital ischemia are important factors to predict the development of new DUs.
A further study confirmed that the decrease in the capillary number and consequently the increase in the intercapillary distance was related to the presence of current digital ulcers.
Pulmonary arterial hypertension (PAH) is a complication of SSc due to increased vascular resistance, and abnormal vascularity is a well-known feature of the disease as shown by NC.
Recently, by comparing mean pulmonary artery pressure (mPAP) with NC parameters, significant correlations between mPAP values and the NC score and with the avascular areas score were found (7).
Generally, data from EUSTAR database have underlined the value of NC for screening and monitoring of SSc patients, since this diagnostic and safe method of investigation may be considered a mirror of internal organ involvement and progression (8,9). In addition, several studies on the potential use of NC in monitoring the drug-induced effects on microcirculation in SSc have been published and improvement of SSc-related microangiopathy has been demonstrated noninvasively by NC with combination therapies. For example, in increased in number of capillaries density and ramifications was noted both after 1 year treatment with iloprost and cyclosporin A, and after 1-2-3-year with iloprost and bosentan.
The significant increasing number of capillaries as quantified at NC, may both predictive and prognostic for a success of combination therapies in SSc (10).
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Disclosure of Interest None declared