Ultrasound Is a Useful Tool to Assess Disease Activity and Treatment Response in Giant Cell Arteritis

Ultrasound is a feasible imaging tool to monitor patients with giant cell arteritis (GCA), with both temporal and axillary artery halo-specific features showing sensitivity to change, according to study results published in Annals of the Rheumatic Diseases. Study results also suggested a significant association between temporal artery halo features and disease activity markers and glucocorticoid cumulative dose.

A team of researchers conducted a prospective observational cohort study including patients with newly diagnosed GCA to determine the sensitivity to changes of ultrasound halo features and their correlation with disease activity and glucocorticoid treatment.

A total of 49 patients (73.5% women; mean age, 78.2 years) with ultrasound-confirmed GCA underwent serial ultrasound assessments of the temporal and axillary arteries at fixed time points, during which the number of segments with halo and maximum halo intima-media thickness were recorded. Researchers then compared disease presentation and first relapse.

A total of 354 visits were recorded during the study period, with a mean of 7.2 visits during a mean of 307.5 days. Prior to ultrasound initiation, patients received treatment with high doses of glucocorticoids for a mean of 2.5 days and had a mean cumulative prednisolone (or equivalent) dose of 927.3 mg. At baseline ultrasound, all patients had at least 1 arterial segment with a halo sign; 220 arterial segments with halo were recorded (201 and 19 temporal and axillary artery segments, respectively). Of the cohort, 47 (95.9%) patients had temporal artery involvement, 2 (22.4%) had axillary involvement, and 9 (18.4%) had both.

Halo sensitivity to change was measured at baseline and at weeks 1, 3, 6, 12, and 24. A total of 250 assessment visits were included. Of the 36 patients at week 24, 16 (44.4%) were reported to have a halo sign; 12 patients had temporal artery involvement and 5 patients had axillary involvement. Disease relapse was observed in 3 (18.8%) patients; however, there was an increase in the number of arterial segments with halo and halo size in these patients compared with that of previous visits recorded.

During the course of the 24-week follow-up, there was a positive correlation observed between temporal artery halo features and disease activity markers, such as erythrocyte sedimentation rate, C-reactive protein, and Birmingham Vasculitis Activity Score; however, no significant correlation was noted for axillary artery halo features.

Patients with a smaller number of temporal artery arterial segments with halo and lower values of temporal artery intima-media thickness were more likely to achieve disease remission. However, this association was not observed with axillary halo features.

Study limitations included the fact that the ultrasonographers were not blinded to clinical data and that many patients were referred to the study by the ophthalmology department, thus increasing the bias toward a more cranial phenotype of GCA.

“Assessment of ultrasound-specific halo features, instead of the current binary presence/absence of halo sign in any arterial segment, should be used to evaluate disease activity and response to treatment in patients with GCA. Future clinical trials in GCA should study treatment effect on halo features as an outcome measure,” the researchers noted.

Reference

Ponte C, Monti S, Scirè CA, et al. Ultrasound halo sign as a potential monitoring tool for patients with giant cell arteritis: a prospective analysis. Ann Rheum Dis. Published online July 2, 2021. doi:10.1136/annrheumdis-2021-220306