Background Calcinosis and acro-osteolysis are frequent in systemic sclerosis (SSc) and are easily detected by X-rays (1). Recent findings indicate that these lesions may be related to digital vasculopathy. Accumulating evidence support the input of nailfold videocapillaroscopy (NVC) as a marker of digital vasculopathy.
Objectives To determine whether calcinosis and acro-osteolysis are associated with specific NVC features.
Methods Consecutive SSc patients were consecutively included during a 24-month period. NVC was performed and analysed by one investigator (JA) blinded for the results of X-Rays and classified as early, active and late pattern (2). Two independent investigators carried out radiological assessment on standard anteroposterior views of the hands and wrists (LM, MS), followed by a consensus reading (AF and YA). Calcinosis was defined by the presence of at least one calcification in soft tissue and acro-osteolysis by the presence of the resorption of at least one digit tip. Both were classified on X-rays as mild, moderate or severe according to their extent.
Results 155 patients were included, with a mean age of 57±13 years and a mean disease duration of 9±5 years; 65 (42%) had the diffuse cutaneous subset. 15 (10%) patients had a normal, 46 (30%) an early, 47 (30%) an active, and 47 (30%) a late NVC pattern. Regarding X-ray analysis, the kappa coefficient of inter-rater agreement was 0.75. 43 (28%) patients had calcinosis, of whom 26 (17%) had moderate or severe lesions; 25 (16%) patients had acro-osteolysis; of whom 13 (8%) had severe lesions. Patients with calcinosis were more likely to have acro-osteolysis (p=0.02), but Cramer's V coefficient of association was 0.19, supporting low association between these variables.
Patients with calcinosis and acro-osteolysis were more likely to have the late NVC pattern (p=0.04 and p<0.0001 respectively). In line with this result, significant capillary loss was observed in patients with calcinosis (4±1.9 vs. 5.5±2.4 mean capillaries/finger, p=0.001) and acro-osteolysis (2.8±1.3 vs. 5.6±2.27 capillaries/finger, p<0.001). Of note, association with the late NVC pattern was stronger (p=0.01) and capillary loss was more pronounced in patients with moderate or severe calcinosis (p<0.001). No association was observed between calcinosis and irregular enlargement of capillaries (neoangiogenesis). Conversely, neoangiogenesis was more frequently observed in patients with severe acro-osteolysis (p=0.03). Multivariate logistic regression analysis confirmed the independent association between calcinosis (p=0.03) and acro-osteolysis (p=0.01) with the late NVC pattern, together with a modified Rodnan skin score >14 (p=0008) and positive antitopoisomerase-I antibodies (p=0.01).
Conclusions We show for the first time an independent association between calcinosis/acro-osteolysis and the late NVC pattern, and in particular, with reduced number of capillaries. This result suggests that these lesions may be related to the severe capillary loss observed at this stage. Acro-osteolysis, but not calcinosis, was associated with neoangiogenesis, which may suggest an attempt to compensate bone resorption. Further studies are now needed to determine whether capillaroscopy may predict the further occurrence or worsening of these lesions.
Avouac J et al, Ann Rheum Dis 2006; (2) Cutolo M et al. J Rheumatol. 2000
Disclosure of Interest None declared