P10 Rapid-access temporal artery ultrasound by vascular sonographers in suspected GCA: an audit during and after a training phase
Authors: Devonshire Laura , Koutsianas Christos , Ostrowski Anna , Trumper Monica , Randhawa Kiran , Klocke Rainer 
Published: April 2020

Abstract

Background
Fast, same-day access ultrasound (US) of temporal (TA) and axillary (AxA) arteries has emerged as part of a gold standard of assessment for suspected giant cell arteritis (GCA). GCA is a rheumatological emergency but many rheumatology units lack expertise and capacity to provide such a service themselves. We audited US scanning for GCA by experienced vascular sonographers, but new to TA scanning, during and after a training phase.

Methods
Before the training audit a meeting between three vascular sonographers (LD, AO and MT), the radiology US Lead (KR) and an experienced rheumatologist sonographer (RK) took place to share the rationale, technique and evidence-base of TA/AXA scanning in suspected GCA. Early during the training period ad hoc co-scanning between technicians and RK/KR was performed and one technician attended the Vascular Scanning Unit at Nuffield Orthopaedic Centre in Oxford. Rheumatology medical staff was encouraged to refer all patients with suspected GCA to the Vascular US unit for scanning, with patients and clinicians being aware that the scan was for training purposes only. At the end of the training period, a sample review of images and reports was undertaken and diagnostic criteria and terminology rehearsed before service scanning commenced.

Results
Twenty-six subjects were scanned during the training period between July 2018 and May 2019: mean [range] 73 [53-89] years, 77% female. Of these 9 (35%) showed US changes reported as diagnostic of GCA in TAs, one equivocal and the remainder negative for GCA. Three of the 9 US-positive subjects underwent TA biopsy, which confirmed GCA in all cases. Of the 6 cases not undergoing biopsy, all were treated as GCA except one (3rd US training case, ESR 2). A total of 10 (38%) of all subjects underwent TA biopsy of which 7 showed a negative biopsy and negative TA US for GCA, thus resulting in a 100 % concordance of US and TA biopsy. In the first 4 months following the training phase, 23 subjects have been scanned for suspected GCA (mean [range] 69 [53-87] years, 65 % female): diagnostic, equivocal and negative changes for GCA were seen in 4, 2 and 17 subjects, respectively. No US-positive and 3 US-negative subjects underwent TA biopsy which showed negative histology for GCA in all three. Duration of steroid treatment before US and TA biopsy was a median 1 (IQR 0.75-4.0) and 6.5 (IQR 5.0-9.5) days, respectively, across both cohorts.

Conclusion
This audit suggests that experienced general vascular sonographers can achieve good proficiency in TA/AxA US for suspected GCA with excellent concordance with TA biopsy results to support a rapid-access clinical pathway for patients with suspected GCA. Furthermore, the audit suggests a reduction in biopsy rates in subjects whose US is positive for GCA.

Disclosures
L. Devonshire None. C. Koutsianas None. A. Ostrowski None. M. Trumper None. K. Randhawa None. R. Klocke None.