212. The anteromedial ultrasound of the large vessels in patients with Giant Cell Arteritis

Background: Giant cell arteritis (GCA) affects both the cranial and large vessels. Ultra-sonographic studies have reported that large vessel vasculitis (LVV) in patients with GCA varies from 30% to 55%. This study aimed to investigate the rate of LVV in patients with GCA by using the anteromedial approach to examine the large supraaortic vessels in addition to the cranial arteries. Methods: Patients with new-onset GCA referred to the Department of Rheumatology, Martina Hansens Hospital in Bærum, Norway, were examined between September 2017 and July 2021. The diagnosis was based on the typical clinical manifestations and verified six months after the diagnosis. All the patients were scanned by ultrasound, using the anteromedial approach for the supraaortic vessels (carotid, vertebral, subclavian, axillary proximally and distally) and the examination of the cranial vessels (temporal, facial). In a selected group of patients, the ascending aorta and the aortic arch were also examined. The anteromedial approach consists of a continuous ultrasound evaluation of the large supraaortic vessels with the patient prone. The examination utilized a GE S8 ultrasound machine and an Applio 800 with 9-12 Mhz linear probes for the large vessels and >18Mhz probes One hundred for the cranial arteries. The age, gender, CRP and the distribution of vasculitis in the vessels were recorded. Results: One hundred twenty-three patients, 82 (85%) females, and 41 (25%) males, were diagnosed with GCA during the recruitment period. The mean age was 72,6 years (95% CI (71-74)) for the female patients and 73 years (95% CI (69-74)) for the male patients. Mean CRP was 99 mg/dl (95% CI (87-110)). Of the 123 GCA patients, 35 patients (28 %) had cranial GCA only, 21 patients (17%) had LVV only, and 67 patients (55 %) had mixed disease (both cranial and LVV GCA). Five patients suffered a visual loss (4%). Fifty-seven patients had an ultrasound evaluation of the ascending aorta, and arch and four of them had an increased diameter of the aortic area >= 40 mm. The temporal arteries were the most frequently involved cranial vessels in 81% of the patients,while the facial artery was involved in 41%. The large supraaortic vessels primarily involved were the right proximal axillary (33%), the left proximal axillary (32 %), the left distal axillary (32 %), the right distal axillary (31 %), and the subclavian (left 26% and right 30 %). The left carotid and vertebral were involved in 17 % of patients, while the right carotid in 9 % and right vertebral in 20% of the patients. Conclusions: The anteromedial ultrasound examination revealed inflammation of the large supraaortic vessels in 72% of the GCA patients indicating that the involvement of supraaortic arteries is more common in GCA than previously reported. In our cohort, only a small percentage of patients (4%) suffered a visual loss. Disclosures: None declared. Preliminary data published here: https://acrabstracts.org/abstract/the-anteromedial-ultrasound-examination-of-the-large-supraaortic-vessels-identifies-higher-rates-of-large-vessel-involvement-than-previous-reported-in-patients-with-giant-cell-arteritis