5. Diagnostic algorithm to evaluate the clinical significance of small-vessel vasculitis surrounding a normal temporal artery
Creators: name: Espigol-Frigolé, Georgina
name: Rios-Garcés, Roberto
name: Prieto-González, Sergio
name: Marco-Hernández, Javier
name: Alba-Rovira, Roser
name: Corbera-Bellalta, Marc
name: Alba, Marco A
name: Kamberovic, Farah
name: Hernández-Rodríguez, José
name: Grau, Josep M
name: Cid, Maria C
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background:</strong> Systemic vasculitides are complex and heterogeneous diseases with overlapping features that frequently pose a diagnostic challenge to clinicians. The temporal artery biopsy (TAB) is the primary modality for establishing a diagnosis of giant cell arteritis (GCA) but, occasionally, TAB show small vessel inflammation (SVI) surrounding a spared temporal artery as the only pathologic finding. Ultimate diagnosis and, consequently, optimal treatment remain uncertain in these patients<strong>. Objective:</strong> To analyze the final diagnosis of patients with SVI surrounding a spared temporal artery after a pre-established diagnostic algorithm and to identify clinical and laboratory findings with potential usefulness in predicting the ultimate diagnosis. <strong>Methods</strong>: Patients with TAB showing SVI were subjected to the diagnostic algorithm displayed in figure 1, completed by at least 1 year follow-up. Clinical and laboratory features at the time of diagnosis were recorded. The algorithm led to the following final diagnosis: GCA, other systemic vasculitis (other SV) and unclassifiable vasculitis. Chi-squared and ANOVA tests were used for statistical comparison using IBM SPSS Statistics 20. <strong>Results:</strong> From 1998 to 2017, 826 TAB were performed in our institution. Biopsy disclosing SVI surrounding a normal temporal artery was described in 82 (10%) patients. In all patients TAB was selected as the first invasive procedure because GCA was initially considered the most likely diagnosis. 17 patients declined to undergo subsequent work-up to complete the diagnostic algorithm and 14 died or were lost to follow –up before completing 1 year. All of them were excluded. The study cohort consisted of 47 patients (27 women and 20 men) aged 74.2±9.4 years followed for 55.16±55.20 months. 36 (76%) fulfilled at least 3 ACR classification criteria for GCA. In 17 patients the final diagnosis was consistent with GCA based on the absence of small vessel vasculitis (SVV) in other territories, large-vessel inflammation by imaging or subsequent development of aortic aneurysm; in 19 SVV was subsequently demonstrated in other territories and were diagnosed with other SV (11 ANCA-vasculitis, 1 cryoglobulinemia, 2 PAN, 5 vasculitis associated to autoimmune diseases) and in 11 diagnosis remained undetermined. <strong>Conclusion:</strong> SVV surrounding a spared temporal artery is a relevant but equivocal finding in TAB. After a detailed diagnostic work-up most patients can be diagnosed with GCA or other systemic vasculitis although diagnosis remains uncertain in some cases. Search for more accurate molecular biomarkers is necessary for a better interpretation of these findings. <strong>Disclosures:</strong> Lecturing/Consulting fees from Janssen, Meeting attendance support from Roche and Boehringer