P006 The potential of colour Doppler ultrasound in reducing temporal artery biopsies in suspected giant cell arteritis

Abstract

Abstract Background/Aims Giant cell arteritis (GCA) is an emergency. The initial treatment with high dose glucocorticoids (GC) is often started on clinical suspicion without waiting for temporal artery biopsy (TAB) results. Colour Doppler ultrasound (CDUS) is a simple, non-invasive test which is readily available. However, like any other ultrasound, it is operator dependent. Non-compressible ‘halo sign’ is the most specific abnormality on CDUS. British society for Rheumatology (BSR) guidelines advises to avoid TAB in patients with low clinical probability and negative CDUS as well as in high clinical probability and positive CDUS. Methods We adopted the quality improvement methodology for assessment. Retrospective data of suspected GCA patients was collected over the last two years. CDUS was introduced to investigative plan midway, after eleven months. Two rheumatology consultants were trained in CDUS. Results were compared before and after the introduction of ultrasound as a diagnostic tool. In collecting the data, our main focus for documentation was based on clinical symptoms, CDUS and TAB results. Patient were divided into high, medium and low probability groups based on clinical assessment by a rheumatologist. Final diagnosis was decided on the basis of clinical assessment at 6 months. Results It was a retrospective review from January 2018 to November 2019, 101 patients were referred with suspected GCA. Median age was 72 years (50 - 91 years) with male to female ratio of 1:3. Thirty five patients were referred in the first 11 months and 28.6% were diagnosed with GCA. CDUS and TAB was done in 20% and 49% of patients respectively. Sixty six patients were referred in the next 12 months after CDUS was introduced and 21.2% were diagnosed as GCA. CDUS and TAB were done in 82% and 38% of the patients respectively. We reviewed all TABs in the second phase of QIP (38%). As per current BSR guideline, 8 TABs could have been avoided in patients with positive CDUS and high probability of GCA or negative CDUS and low probability of GCA. Even if we deduct these 8 TABs from total of 25, 26% of our suspected GCA referrals would still require TAB for diagnostic workup. Conclusion After the routine introduction of CDUS, the percentage of patients requiring TAB has declined. Approximately one fourth patients would still require TAB as per BSR guidelines. To improve the clinical relevance of biopsies further we recommended; the routine use of GCA probability score, improve CDUS skills and arrange availability of urgent slots in clinic for CDUS. We also noticed that the number of patients referred has almost doubled. This might be due to better education and awareness at the primary and secondary care level which was done as part of the project. Disclosure A.A. Sidhu: None. A. Nandagudi: None. A. Bharadwaj: None.