Patients with systemic sclerosis (SSc) who underwent bilateral power Doppler ultrasonography of the hands often exhibited synovial involvement, with nearly one-third of individuals showing signs of inflammatory synovitis or sclerosing tenosynovitis, according to findings published in Rheumatology.
Evaluation by power Doppler ultrasound is more sensitive than clinical examination for detection of inflammatory synovitis or sclerosing tenosynovitis in the SSc population. Still, synovial involvement prevalence has remained largely uncertain. Updated descriptions of the pathophysiology seen on power Doppler ultrasound are needed to ensure optimal therapeutic targeting with new anti-inflammatory medications. This was the first study to characterize ultrasonographic synovial involvement in patients with SSc and examine relationships to biological, immunological, and clinical aspects of disease.
From November 2014 through November 2016, researchers examined bilateral hand and wrist power Doppler images of 103 (mean disease duration, 7.6 years) patients with SSc who were diagnosed according to 2013 American College of Rheumatology/European League Against Rheumatism criteria, assessing all participants for synovitis or tenosynovitis. A single rheumatologist using OMERACT definitions read all patients’ sonograms, blinded to other relevant clinical, radiological, and laboratory findings. Odds ratios (ORs) were calculated to estimate the likelihood of results.
There were 33 (32%) individuals who displayed synovitis or tenosynovitis on power Doppler ultrasound, with the majority classified as positive for inflammatory synovitis (n=18; 17.5%) or sclerosing tenosynovitis (n=19; 18.4%). Synovitis was seen more often in the metacarpophalangeal and wrist joints; sclerosing tenosynovitis occurred more frequently in men (OR, 6.32; 95% CI, 2.17-18.41; P =.001).
Sclerosing tenosynovitis was also significantly related to anti-RNA polymerase III positivity (OR, 10.93; 95% CI, 1.84-65.12; P =.01), inflammatory arthralgia (OR, 14.64, 95% CI, 2.58-83.10; P =.002), interstitial lung disease (OR, 6.09; 95% CI, 1.86-19.98; P =.001), and diffuse disease (OR, 18.24; 95% CI, 4.80-69.32; P <.0001). Inflammatory synovitis and tenosynovitis were correlated with inflammatory arthralgia (OR, 15.96; 95% CI, 2.80-91.02; P =.002), pericarditis (OR, 7.81; 95% CI, 1.58-38.71; P =.017) and C-reactive protein >5 mg/L (OR, 5.50; 95% CI, 1.81-16.70; P =.001).
Within individual patients, sclerosing tenosynovitis and inflammatory synovitis were not significantly linked (OR, 2.77; 95% CI, 0.88-8.70; P =.095); and there were no associations detected within the cohort between power Doppler ultrasound synovial involvement and calcinosis, acro-osteolysis, or digital ulcers.
Study limitations included not examining calcinosis via power Doppler ultrasound, incomplete comparisons between power Doppler ultrasound and clinical findings, lack of multivariate analysis, nonexploration of independent contributors to synovial involvement, small sample size that limited statistical power, exclusion of capillaroscopic considerations, and a cross-sectional design that prevented causal conclusions.
“[Ultrasound] evaluation should not replace physical examination of the hand but may help to describe more precisely the pathologic mechanisms involving the hand in SSc,” advised the authors, who recommended future longitudinal trials involving larger sample sizes.
Lescoat A, Ballerie A, Belhomme N, et al. Synovial involvement assessed by power Doppler ultrasonography in systemic sclerosis: results of a cross-sectional study [published online July 28, 2018]. Rheumatology (Oxford). doi:10.1093/rheumatology/key214