Impact of cranial and axillary/subclavian artery involvement by color duplex sonography on response to treatment in giant cell arteritis

Abstract

Color duplex sonography (CDS) today is broadly used in the diagnostic workup of patients with suspected cranial or extracranial giant cell arteritis (GCA). This study aimed to determine the prognostic impact of the disease pattern assessed by CDS on the treatment response in GCA. This was a retrospective, longitudinal follow-up study of 43 patients who were diagnosed with GCA at our institution between 2002 and 2010. All patients underwent CDS of the temporal and subclavian/axillary arteries at baseline and were observed for at least 6 months. Vasculitis was sonographically characterized by a circumferential, hypoechogenic wall thickening. According to the CDS findings, patients were categorized into patients with involvement of the subclavian/axillary arteries only (group A1, n = 17), patients with involvement of both the subclavian/axillary arteries and the temporal arteries (group A2, n = 9), and patients with isolated cranial GCA (group B, n = 17). Data on recurrences, corticosteroid doses, and steroid-sparing agents were extracted from the medical records. Treatment response over time was analyzed by Kaplan-Meier curves with log-rank testing. The mean follow-up time was 25.4 months and did not differ between groups (P = .4). Patients in group A1 were significantly younger than patients in groups A2 and B (P < .01). The interval between symptom onset and diagnosis was significantly longer in groups A1 and A2 compared with group B (P < .01). The number of recurrences per month was significantly higher in group A2 compared with group A1 and group B (A1, 0.07; A2, 0.13; B, 0.03; P < .01). Whereas there were no significant differences in the mean time until a daily prednisolone dose <10 mg was reached, patients in group A2 more frequently required steroid-sparing agents (A1, 24%; A2, 56%; B, 24%; P = .04). Extensive vascular involvement of both the temporal and subclavian/axillary arteries, as depicted by CDS, may be associated with a poor treatment response in GCA.