P299 What happens if the rheumatologist is no longer the gatekeeper to temporal artery ultrasound in giant cell arteritis?
Authors: Redfern Angela , Benson Rosalind , Cotton Caroline , Amoasii Constanta , Mewar Devesh 
Published: April 2022

Abstract

Background/Aims
Prior to 2019, temporal artery ultrasound (TAUS) was introduced under close supervision of rheumatology consultants to support the diagnosis of giant cell arteritis (GCA). Evaluation of these early scans highlighted how the majority of patients presented via the acute medical unit (AMU). In 2019 a GCA fast-track pathway (GCA-FTP) was introduced at our centre in collaboration with AMU colleagues. The aim was to promote early utilisation of TAUS by expanding access of this test to physicians working across acute care prior to specialist rheumatology input, in contrast to many other units. This evaluation sought to establish if the new GCA-FTP led to improved presentation to scan times, as well as assessing the impact on availability of TAUS.

Methods
A retrospective analysis of data was carried out on all patients referred with suspected GCA for TAUS during a 4-month period in 2020. Results were compared with those from the 2019 evaluation and benchmarked against BSR GCA guidelines. An ultrasound was considered positive if a definite halo sign, or irregular thickening consistent with arteritis, was reported. Clinical records were reviewed to identify the final diagnosis made following the rheumatology consult. The rheumatologist’s intention to treat for GCA was considered the ‘gold standard’.

Results
We identified 58 patients (39 female, 19 male) with a mean age of 68 years (range 40-90). A positive TAUS was reported in 7/58 cases, with 4/58 reported as inconclusive and 47/58 as negative. A positive ultrasound in our cohort carried a sensitivity of 64% and specificity of 100%. A total of 50 patients were referred to a rheumatologist, of which 17/50 (34%) were reviewed on the same day. 8 patients were given an alternative diagnosis without rheumatology input and were deemed to have low clinical probability of GCA. The average number of scans per week was 2.2, compared to 0.4 pre pathway. The scans were requested by rheumatologists (21/58, 36%), acute physicians (15/58, 26%), ophthalmologists (13/58, 22%), emergency department physicians (1/58, 2%), other (5/58, 9%) and unknown source (3/58, 5%). Median time from initial review to scan request was &lt;1 working day compared to 2 days pre-pathway. Median time from scan request to performance was 1 working day (previously 2 days). All scans were performed within 4 days of the request.

Conclusion
Despite reservations that enabling the non-specialist physician to access TAUS might overwhelm TAUS capacity, we have shown the opposite. Despite the higher volume of requests, the scans were requested earlier in the patient journey and performed more quickly. Diagnostic specificity remained high, despite more than 50% of the TAUS studies being requested by non-rheumatologists. We have shown that acute care physicians were able to successfully initiate diagnostic work-up in a collaborative GCA pathway.

Disclosure
A. Redfern: None. R. Benson: None. C. Cotton: None. C. Amoasii: None. D. Mewar: None.