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THU0296 The role of ultrasound in the management of giant cell arteritis (GCA) in routine clinical practice
  1. S Monti1,2,
  2. A Floris3,
  3. C Ponte4,
  4. S Vaggers2,
  5. WA Schmidt5,
  6. AP Diamantopoulos6,
  7. C Pereira2,
  8. R Luqmani2
  1. 1Rheumatology, University of Pavia, IRCCS Policlinico San Matteo Foundation, Pavia, Italy, Pavia, Italy
  2. 2NDORMS, Rheumatology Department, Nuffield Orthopaedic Centre, University of Oxford, Oxford, United Kingdom
  3. 3Rheumatology, University Clinic and AOU of Cagliari, Cagliari, Italy
  4. 4Rheumatology, Hospital de Santa Maria, Rheumatology research Unit Instituto de Medicina Molecular, Lisbon Academic Medical Centre, Lisbon, Portugal
  5. 5Rheumatology, Immanuel Krankenhaus Berlin, Medical Centre for Rheumatology Berlin-Bu, Berlin, Germany
  6. 6Rheumatology, Hospital of Southern Norway Trust, Kristiansand, Norway

Abstract

Background Colour Doppler sonography (CDS) is an emerging diagnostic tool for giant cell arteritis (GCA), however, its use in routine practice is still not widespread.

Objectives To develop a protocol using CDS and explore its value in the routine care of patients with GCA.

Methods We developed a structured scanning protocol for CDS of temporal and axillary arteries (total of 8 anatomical sites scanned per patient) based on previously published methods. We tested the protocol on consecutive patients referred to a single rheumatology centre, with suspected or established GCA, between July 2014 and September 2016. We defined a positive scan by the presence of halo in at least one branch of a temporal artery (TA) or one axillary artery (AX). We report data from the first 293 consecutively scanned cases.

Results We assessed 293 patients (mean age 72±10, female/male 196/97), of whom 118 had clinically confirmed GCA. Amongst new referrals with confirmed diagnosis of GCA, 44% had a positive scan; two patients with a positive scan did not have GCA. 82% of new referrals patients showed exclusive TA involvement, 25% concomitant AX, and 4% exclusive AX involvement. High-dose glucocorticoid therapy had already been started in 78% of these patients for an average of 17±33 days. Amongst this group, the sensitivity of CDS was 46% (95% IC 37%>55%), specificity 98% (95% CI 93%>99.8%), positive predictive value 96% (88%>99.6%), and negative predictive value 60% (95% IC 52%>68%). During the period of observation, the rate of temporal artery biopsies (TAB) decreased significantly from 42% to 25% (p=0.002). During follow up, CDS was positive in 21% of 89 routine scans in asymptomatic individuals, compared to 58% in patients with confirmed clinical flares (45% of whom had negative inflammatory markers). Over time, the number of halos per patient reduced; only new or flaring patients showed a halo in >4 sites. Halo size at the TA did not change significantly (average thickness 0.6±0.1 mm), however, the size of AX artery halos significantly reduced from first referral (1.6±0.4 mm) to follow up (1.4±0.2, p=0.01) or during subsequent flares (1.4±0.2, p=0.02).

Conclusions We have developed and tested a standardised methodology for CDS evaluation of GCA. CDS provides a high positive predictive value for a diagnosis of GCA in unselected patients from routine clinical practice, although prior high dose glucocorticoid therapy is likely to reduce its sensitivity. CDS allows for a significant reduction of TAB. We explored the role of CDS to detect disease flares and demonstrated a significant reduction in the extent of abnormalities, and of the size of halo of the AX arteries during follow up or flares. These findings could have a significant impact on the management of patients with suspected and confirmed GCA.

Disclosure of Interest None declared

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