The results of large scale study presented at the Annual European Congress of Rheumatology (EULAR) 2017 demonstrated that patients meeting the 'very early diagnosis of systemic sclerosis' (VEDOSS) criteria predominantly have the characteristic appearance of an early SSc pattern when they are investigated using a technique known as nailfold videocapillaroscopy.

Nailfold videocapillaroscopy is a non–invasive, inexpensive and reproducible imaging method allowing the evaluation of structural changes in the peripheral microcirculation. Consisting of a combination of a microscope with a large magnification lens coupled with a digital video camera aided by specific software, this technique allows a precise measurement of the morphology of capillaries and their density.

The characteristic appearance of an early SSc pattern during nailfold videocapillaroscopy includes the presence of giant capillaries and haemorrhages. Conversely, loss of capillaries, vascular architectural disorganisation and the presence of abnormally shaped capillaries represent the clearest aspect of advanced SSc microvascular damage, which has also been associated with organ involvement in clinically overt SSc.

"Because SSc is usually preceded by the presence of Raynaud's phenomenon , this provides an ideal opportunity to investigate the earliest damage to the microcirculation," said lead author Professor Vanessa Smith from Ghent University Hospital, Ghent, Belgium.

"Nailfold videocapillaroscopy should be regarded as a key component of the VEDOSS criteria (that also encompass clinical changes to the microcirculation "Raynaud's phenomenon", presence of antinuclear antibodies in the circulation and puffy digits), which have been specifically designed to diagnose SSc as early as possible. One of the aims of studying the disease in such an early cohort is to find targets to ultimately treat the disease before irreversible tissue damage has occurred," she explained.

The prevalence of nailfold videocapillaroscopy early SSc patterns was higher in the Anti–Nuclear Antibody (ANA) positive VEDOSS patients than those without this antibody. The estimated distribution of early SSc patterns were 40% vs. 13% in the ANA+ and ANA– patients respectively. A typical "early" pattern was present in 79% of "target" patients.

For the quantitative capillaroscopic characteristics, the only statistically significant difference between the ANA+ and ANA– patients was in the presence of "moderate" or "extensive" giant capillaries (23 vs. 5%, p=0.027).

40 centres took part in the VEDOSS endeavour leading to a database with 1,085 patients with Raynaud's phenomenon. These patients were divided into two main groups: ANA+ patients and those without this antibody in their circulation.

Nailfold videocapillaroscopy patterns were categorised as follows: normal / non–specific alterations; non–specific abnormalities; "Early", "Active"; "Late"; and "Scleroderma–like" SSc–patterns. A quantitative assessment of capillaroscopic alterations included "absent ("none" or "rare") and "present" ("moderate" or "extensive") for the appearance of giant capillaries, haemorrhages, capillary loss and abnormally–shaped (bushy) capillaries.