The use of color duplex sonography (CDS) in the diagnosis of patients with suspected giant cell arteritis (GCA) is associated with high specificity and positive predictive value, thus reducing the need for temporal artery biopsies, according to the results of a recent study published in Rheumatology.1 CDS includes routine assessment of temporal arteries and axillary arteries.
The investigators performed 377 CDS scans of temporal and axillary arteries in 293 consecutive patients (mean age, 72±10; 67% women; 73% on high-dose glucocorticoid therapy for 17±33 days) with either suspected or established GCA, from July 2014 through September 2016. Overall, 56% of the scans were performed on patients referred for suspected GCA, 24% were on regular follow-up appointments for patients with diagnosed GCA, and 20% were on patients with established GCA and a suspicion of disease flare.
Among new referrals with <7 days of glucocorticoid treatment (n=55), the sensitivity of CDS was 63.3% (95% CI, 44%-88%), the specificity was 100% (95% CI, 83%-100%), the positive predictive value was 100%, and the negative predictive value was 64.5% (95% CI, 53%-74%). The sensitivity in patients with jaw claudication and high levels of inflammatory markers increased to 81.8% (95% CI, 48%-98%) and the specificity remained at 100% (95% CI, 2.5%-100%).
During the observation phase, the overall number of temporal artery biopsies decreased significantly from 72 (42%) in the historic cohort to 36 (25%) in the recent cohort (P =.002). CDS was positive in 21% of 89 follow-up scans of asymptomatic patients, vs 37% in participants with disease flares. The number of halos reported by patients decreased over time, with only new patients or patients experiencing flares exhibiting a halo in ≥4 sites. The diameter of axillary halos decreased from referral (1.6±0.4 mm) to follow-up (1.4±0.2 mm; P =.01) or flares (1.4±0.2 mm; P =.02).
The investigators concluded “CDS provides high positive predictive value for diagnosing GCA and allows for a significant reduction in temporal artery biopsies,” thus demonstrating that fast-track services should be implemented for GCA diagnosis.
Monti S, Floris A, Ponte CB, et al. The proposed role of ultrasound in the management of giant cell arteritis in routine clinical practice [published online October 16, 2017]. Rheumatology (Oxford). doi:10.1093/rheumatology/kex341