Extended ultrasound examination identifies more large vessel involvement in patients with giant cell arteritis

Objectives To compare limited with a more extended ultrasound examination (anteromedial ultrasound, A2-ultrasound) to detect large vessel (LV) involvement in patients with newly diagnosed GCA. Methods Patients with new-onset GCA were included at the time of diagnosis. All patients were examined using limited ultrasound (ultrasound of the axillary artery as visualized in the axilla) and an extended A2-ultrasound method (which also includes the carotid, vertebral, subclavian and proximal axillary arteries), in addition to temporal artery ultrasound. Results One hundred and thirty-three patients were included in the study. All patients fulfilled the criteria according to a proposed extension of the 1990 ACR classification criteria for GCA and had a positive ultrasound examination at diagnosis. Ninety-three of the 133 GCA patients (69.9%) had LV involvement when examined by extended A2-ultrasound, compared with only 56 patients (42.1%) by limited ultrasound (P < 0.001). Twelve patients (9.0%) had vasculitis of the vertebral arteries as the only LVs involved. Five patients (3.8%) would have been missed as having GCA if only limited ultrasound was performed. Forty patients (30.0%) had isolated cranial GCA, 21 patients (15.8%) had isolated large vessel GCA and 72 patients (54.1%) had mixed-GCA. Conclusion Extended A2-ultrasound examination identified more patients with LV involvement than the limited ultrasound method. However, extended A2-ultrasound requires high expertise and high-end equipment and should be performed by ultrasonographers with adequate training.