POS0812 SUBCLAVIAN ARTERIES INVOLVEMENT IN PATIENTS WITH GIANT CELL ARTERITIS: DO WE NEED A MODIFIED HALO SCORE?

Background:EULAR recommendations propose temporal and axillary arteries ultrasound (US) as first-line investigation when predominantly cranial giant cell arteritis (GCA) is suspected. Recently, two novel US scoring systems, the halo count and the Southend Halo Score, have been developed to quantify the extent of inflammation by US in GCA.Objectives:To assess whether adding the subclavian arteries examination into the ultrasound (US) Southend Halo Score, as proposed in the modified Halo Score, improves the diagnostic accuracy of GCA and its relationship with systemic inflammation.Methods:Retrospective observational study of patients referred to a GCA fast track pathway (FTP) over a 1-year period. Patients underwent US exam of temporal and large vessel (LV) (carotid, subclavian and axillary) arteries. The extent of inflammation was measured by the halo count, the Southend Halo Score and the modified Halo Score (Image 1). The gold standard for GCA diagnosis was clinical confirmation after 6 months follow-up.Results:64 patients were evaluated in the FTP, 17(26.5%) had GCA. Subclavian arteries involvement was present only in patients with GCA (29.4% versus 0%,pFigure 1.Proposed scores to quantify the extent of vascular inflammation by ultrasound in giant cell arteritis. A. Halo count, B. Halo Score, C: Modified Halo ScoreTable 1.Clinical, laboratory and ultrasound findings of patients included in the fast track pathway with or without GCA clinical confirmation.Totaln=64Patients with GCAn=17Patients without GCAn=47pAge, median (IQR)78 (69.3-83)78 (72.5-83)78 (66-83)0.5Female, n (%)42 (65.6%)10 (58.8%)32 (68.1%)0.491Temporal artery biopsy positive n=13, no. of patients5 (38.5%)5 (50%)0 (0%)0.23118F-FDG-PET/CT positive n=14, no. of patients7 (50%)5 (62.5%)2 (33.3%)0.592Fulfilling 1990 GCA criteria, no. of patients16 (25%)8 (47.1%)8 (17%)0.022PMR diagnosis before US examination, no. of patients21 (32.8%)4 (23,5%)17 (36,2%)0.386Headache, no. of patients31 (48.4%)12 (70.6%)19 (40.4%)0.033Jaw claudication, no. of patients12 (18.8%)9 (52.9%)3 (6.4%)Ocular ischaemia, no. of patients4 (6.3%)2 (11.8%)2 (4.3%)0.285Abnormal TA clinical examination, no. of patients5 (7.8%)3 (17.6%)2 (4.3%)0.112CRP (mg/dL), median (IQR)1.7(0-6.5)7 (2.1-14)1.1 (0-5.1)0.001ESR (mm/h), mean (SD)52.8 (34.6)68.3 (33.3)46.8 (33.3)0.044Haemoglobin (g/dL), mean (SD)12.5 (1.7)11.8 (1.6)12.7 (1.7)0.059Platelets 109/L, mean (SD)276.1 (105.8)323.4 (116.3)258.7 (97.3)0.52Positive US findings, no. of patients17 (26.6%)15 (88.2%)2 (4.3%)Temporal artery positive US findings, no. of patients13 (20.3%)12 (70.6%)1 (2.1%)Axillary positive US findings, no. of patients9 (14.1%)8 (47.1%)1 (2.1%)Subclavian positive US findings, no. of patients5 (7.8%)5 (29.4%)0 (0%)Temporal artery + axillary or subclavian positive US findings, no. of patients5 (7.9%)5 (29.4%)0 (0%)0.003Halo Count, median (IQR)0 (0-0.75)2 (1-4.5)0 (0-0)Halo Score, median (IQR)0 (0-4.5)18 (7-22.5))0 (0-0)Modified Halo Score, median (IQR)0 (0-2.75)8 (3-13.5)0 (0-0)Conclusion:The inclusion of subclavian arteries examination in the modified Halo Score does not improve the diagnostic accuracy of GCA. Nevertheless, it correlates better with markers of systemic inflammation in LV-GCADisclosure of Interests:None declared