RESUMEN
OBJECTIVES: Giant cell arteritis (GCA) is the main systemic vasculitis in individuals aged ≥ 50 years. Color Doppler ultrasound (CDS) has an established role in GCA diagnosis and management. This study aims to assess the clinical characteristics associated with a positive CDS evaluation and the impact of additional axillary artery examination on diagnostic sensitivity. MATERIAL AND METHODS: We conducted a retrospective analysis of patients undergoing CDS of the superficial temporal arteries, with or without axillary artery assessment, at our hospital, between 2009 and 2023. Patients meeting the new 2022 diagnostic criteria for GCA were included and their characteristics were analyzed according to the presence of the halo sign on CDS. RESULTS: Of the 135 included patients (54 % female, mean age 75 ± 8 years), the halo sign was observed in 57 %, correlating with higher systemic symptom prevalence (61 % vs 42 %, p = 0.035), lower hemoglobin (p < 0.001), and higher erythrocyte sedimentation rate (p = 0.028). The halo sign inversely related to prior corticosteroid therapy (p = 0.033). Patients with axillary halo sign had fewer external carotid symptoms and a higher vertebral halo sign prevalence. Vertebral halo sign was associated with posterior circulation ischemic stroke (65 %, p < 0.001). Axillary artery studies improved diagnostic sensitivity by 9 %. CONCLUSION: In our study, the halo sign correlated with higher systemic symptoms and analytical abnormalities. Axillary artery examination enhanced CDS sensitivity, linked to severe outcomes like stroke. Prior corticosteroid therapy reduced CDS sensitivity. The correlation of clinical, laboratory, and ultrasound findings provides a more comprehensive understanding of GCA pathogenesis and evolution.