Nailfold videocapillaroscopy can help to predict which patients with systemic sclerosis may develop serious cardiopulmonary complications, according to findings from a Dutch cross-sectional study.
While individual autoantibodies seen in systemic sclerosis (SSc) are known to be associated with greater or lesser risk of cardiopulmonary involvement, in this study nailfold vascularization patterns independently predicted pulmonary artery hypertension or interstitial lung disease.
ACR Copyright 2017
Nailfold capillaroscopy images show progressively worsening damage: microhemorrhage and hemosiderin (top left), an isolated dilated loop (top right), lower capillary density and microhemorrhage (lower right), and architectural derangement (lower left).
All patients in the study had NVC pattern data as well as anti-extractable nuclear antigen (anti-ENA) antibodies. The mean age of the patients was 54 years; 82% were female, and median disease duration was 3 years. Just over half the cohort had interstitial lung disease, and 16% had pulmonary artery hypertension.
Among the anti-ENA autoantibody subtypes, anti-ACA was seen in 37% of patients, anti-Scl-70 in 24%, anti-RNP in 9%, and anti-RNAPIII in 5%; other subtypes were rarer. SSc-specific NVC patterns were seen in 88% of patients, with 10% of the cohort showing an early (less severe microangiopathy) pattern, 42% an active pattern, and 36% a late pattern.
One of the study’s objectives was to determine whether one or more mechanisms was responsible for both autoantibody production and the microangiopathy seen in SSc.
If a joint mechanism is implicated, “more severe NVC patterns would be determined in patients with autoantibodies (such as anti-Scl-70 and anti-RNAPIII) that are associated with more severe disease,” wrote Dr. Markusse and her colleagues. “On the other hand, if specific autoantibodies and stage of microangiopathy reflect different processes in the disease, a combination of autoantibody status and NVC could be helpful for identifying patients at highest risk for cardiopulmonary involvement.”
The investigators reported finding a similar distribution of NVC abnormalities across the major SSc autoantibody subtypes (except for anti–RNP-positive patients), suggesting that combinations of the two variables would be most predictive of cardiopulmonary involvement. More severe NVC patterns were associated with a higher risk of cardiopulmonary involvement, independent of the presence of a specific autoantibody.
Notably, the researchers wrote, “prevalence of ILD [interstitial lung disease] is generally lower among ACA-positive patients. According to our data, even among ACA-positive patients there was a trend for more ILD being associated with more severe NVC patterns (OR = 1.33).”
A similar pattern was seen for pulmonary artery hypertension. “Based on anti-RNP and anti-RNAPIII positivity, patients did not have an increased risk of a [systolic pulmonary artery pressure] greater than 35 mm Hg; however, with a severe NVC pattern, this risk was significantly increased (OR = 2.33).”
The investigators cautioned that their findings should be confirmed in larger cohorts. The study by Dr. Markusse and her colleagues was conducted without outside funding, though manufacturers donated diagnostic antibody tests. One of the 11 study coauthors disclosed receiving financial support from Actelion.