Subclavian arteries involvement in patients with giant cell arteritis: do we need a modified Halo Score?

Abstract

Objective: To assess whether adding the subclavian arteries examination into the ultrasound (US) Southend Halo Score, as proposed in the modified Halo Score, improves the diagnostic accuracy of giant cell arteritis (GCA) and its relationship with systemic inflammation.Methods: Retrospective observational study of patients referred to a GCA fast track pathway (FTP) over a 1-year period. Patients underwent US exam of temporal and large vessel (LV) (carotid, subclavian and axillary) arteries. The extent of inflammation was measured by the halo count, the Southend Halo Score and the modified Halo Score. The gold standard for GCA diagnosis was clinical confirmation after 6 months follow-up.Results: 64 patients were evaluated in the FTP, 17(26.5%) had GCA. Subclavian arteries involvement was present only in patients with GCA (29.4% versus 0%,p<0.001). Overall, the three scores showed excellent diagnostic accuracy for GCA (ROC AUC 0.906, 0.930 and 0.928, respectively) and moderate correlations with acute phase reactants (0.35-0.51, p<0.01). Only the modified Halo Score correlated with markers of inflammation in patients with LV involvement. Conclusions: The inclusion of subclavian arteries examination in the modified Halo Score does not improve the diagnostic accuracy of GCA. Nevertheless, it correlates better with markers of systemic inflammation in LV-GCA