ORADE Report: Dr. Stephanie Garner

Dr. Stephanie Garner was the recipient of a 2019 ORADE Grant

The 19^th International Vasculitis and ANCA Workshop was held in the Spring of 2019 in Philadelphia, Pennsylvania.  There were over 500 attendees from over 40 countries, and I was lucky enough to be one of them! There was a strong academic program and the social program included the National Institute of Health band lead by the director of the NIH at the History Reading Terminal Market. The abstracts for this meeting were published in Rheumatology (1).

New (proposed) Classification Criteria in Giant Cell Arteritis

The American College of Rheumatology Classification Criteria for Giant Cell Arteritis (GCA) were published in 1990 and have not been updated since Nirvana was headlining. While leggings are once again in fashion, there have been significant advances in our knowledge of GCA and our approaches to diagnosis. Imaging techniques including ultrasound, magnetic resonance imaging and PET have helped improve our diagnostic yield and reduce the need for biopsies. Ponte et al (Abstract 077) presented the new proposed classification criteria for GCA. The new classification criteria were developed through a five phase process that included review of over 2000 cases of Takayasu’s arteritis and GCA. Logistic regression was employed to identify and weigh the criteria. The criteria were then validated in an independent data set within the Diagnostic and Classification Criteria in Vasculitis. While the new criteria now take into account imaging findings another big change is the drop of “age at diagnosis” from 50 to 40 years. It is important to note that the new criteria have not yet received endorsement by EULAR and ACR.

Criteria: ≥ 6 points meets threshold for classification.

Sensitivity 89.1%, Specificity 91.6%

Updates in Imaging: Giant Cell Arteritis

When discussing ultrasound (US) findings in temporal arteritis, we hope to find a classic “halo sign” of the temporal arteries which has a sensitivity and specificity of 55-100% and 78-100% respectively (2). Diamantopoulos and Haaversen (Abstract 085) from Norway suggested we should broaden our field of view to interrogate the large supra-aortic vessels as it will identify higher rates of large vessel vasculitis. The authors included patients who had typical clinical manifestations of GCA and elevated CRP. They then scanned the supra-aortic arteries (carotid, vertebral, subclavian, axillary arteries) along with the cranial vessels (temporal, facial, and occipital). Of the 28 patients included in the study, six had only cranial disease, 15 patients had US evidence of both extra-cranial and cranial involvement, and seven had only extra-cranial disease. Axillary artery involvement, which is included in the new proposed classification criteria for GCA, was found in 39% of patients. While this was a small study the incidence of extra-cranial disease was quite high (79%) raising the question whether we should be routinely scanning these patients extra-cranially.

The proposed changes to the classification criteria for GCA also include findings of FDG-PET which has a reasonable sensitivity and specificity for LVV (sensitivity 67%–77%, specificity 66-100%) (3). There were several abstracts presented reviewing the utility of FDG-PET scanning in the monitoring of disease activity in large vessel vasculitis. In a prospective cohort of 52 patients with LVV, patients had FDG-PET/CT scans every six months (Abstract 232). Disease activity and treatment changes were tracked over this period. Interestingly the authors noted that FDG-PET/CT activity (as measured by a visual analogue scale) correlated well with clinical disease activity measures when patients had treatment escalated or no changes made in therapy. However, when patients had de-escalation of therapy, FDG-PET/CT activity worsened (p<0.02). Whether this reflects subclinical disease or is not clinically relevant deserves further study. To minimize radiation exposure, FDG-PET/MR has been proposed as a modality for monitoring patients (Abstract 107). While this appeared to work as well as FDG-PET/CT, 50% of patients in clinical remission had evidence of active uptake. This again raises the issue of how clinically useful this modality is. Unfortunately, (or fortunately?) for us here in Ontario, PET scans are not accessible outside oncology and sarcoid.

‘Less is More’ in ANCA Associated Vasculitis

As new medications have been introduced and our management approaches have been refined, patients with ANCA associated vasculitis are no longer commonly dying of the disease itself but rather complications from therapy. The most common cause of death within the first year of treatment is infection; steroids contribute significantly to this. While assessing the benefit of plasma exchange was a significant component of the Plasma Exchange in Vasculitis (PEXIVAS) trial, the other key objective was to assess the efficacy and toxicity of a rapidly tapering regimen of corticosteroids in patients with severe ANCA associated vasculitis (Abstract 361).  Patients were started on traditional dosing (mg/kg) and then in the rapidly tapering group the dose of steroid was halved after week one and then tapered by five mg every two weeks. The primary outcome was a composite measure of death or end stage renal disease (ESRD).  There were 330 patients in the reduced dose group and 325 patients in the standard dose group. No difference in the primary outcome measure (death, ESRD) between the two groups. There were significantly more serious infections in the standard dose group compared to the low dose group (33% standard dose, 27% reduced dose, p= 0.016). This would suggest that we should consider lowering the standard tapering regimen of prednisone that we use in patients with ANCA associated vasculitis.

References

1. 2019 March Volume 58, Supplement 2
2. Buttgereit, et al 2016;315(22):2442-2458.
3. Duftner et al RMD Open.2018 Feb 2;4(1)