Sonographic study on vessel wall remodelling of the cranial and axillary arteries in giant cell arteritis under treatment: implications for diagnosis of relapses and impact of tocilizumab treatment.

Objectives: Giant cell arteritis (GCA) is the most common primary systemic vasculitis and is nowadays commonly diagnosed using vascular ultrasound. Whether repeated ultrasound is helpful in disease management is unclear.

Methods: We conducted a retrospective analysis of 100 patients diagnosed with GCA between 01/2016 and 12/2022. High-resolution ultrasound was performed to assess vasculitic wall thickening in superficial temporal, facial, and axillary arteries at diagnosis and during follow-up. Patients were treated according to current standards, with tocilizumab treatment initiated within 6 months after diagnosis in 38 patients. The course of wall thickening in the different vascular segments was recorded. Patients with and without complete normalisation of wall thickening were compared. The impact of tocilizumab treatment on vessel wall remodelling and the potential benefit of repeated ultrasound examinations for the diagnosis of relapsing disease were assessed.

Results: In the overall cohort (63% females, mean age 72.8±8.9 years), one, two or three arterial territories were affected in 31, 50 and 17 patients. Follow-up ultrasound examinations showed a significant reduction in wall thickening over time: superficial temporal arteries -0.42 mm, facial arteries -0.35 mm, axillary arteries -0.36 mm. Normalisation of wall thickening occurred in 32.6% (superficial temporal arteries), 53.1% (facial arteries), and 35.5% (axillary arteries), with some differences in clinical characteristics between patients with and without complete sonographic remission. Patients treated with tocilizumab showed a slightly faster early reduction in mean intima-media thickness which was lost over time. Repeated ultrasound showed a significant increase in maximum IMT (at least +0.3 mm) in 3.6% of the superficial temporal arteries, 18.4% of the facial arteries, and 21.4% of the axillary arteries in patients with relapsing disease.

Conclusions: Our results help to interpret repeated IMT measurements of the affected cranial and extracranial arteries in patients with GCA undergoing treatment. Repeated ultrasound examinations appear to be of limited diagnostic value in the diagnosis of relapsing GCA.