FRI0361 The Extension of Inflammatory Infiltrates or Intimal Hyperplasia in Temporal Arteries Do Not Significantly Predict CTA-Detection of Aortic Thickening in Newly-Diagnosed Patients with biopsy-proven Giant-Cell Arteritis

BackgroundGiant cell arteritis (GCA) is a granulomatous vasculitis preferentially targeting the carotid and vertebral artery branches. Aortic involvement is common and may lead to severe complications such as aortic dilatation/aneurysm or dissection1. While small necropsy studies detected histopathologically-proven aortic inflammation in more than 90% of patients, aortic wall thickening suggesting aortitis is detected in 65% of patients using CTA at diagnosis 2. We hypothesized that histological features underlying arterial wall thickening (transmural inflammatory infiltrate or intimal hyperplasia) observed in temporal artery biopsies might predict CTA-detection of aortic wall involvement.ObjectivesTo assess whether the extension of inflammatory infiltrates and/or the degree of intimal hyperplasia in temporal artery biopsies (TAB) from GCA patients correlate with CTA detection of aortitis at the time of diagnosis.MethodsTABs from biopsy-proven GCA included in an ongoing prospective study for detection of large vessel vasculitis (LVV) at diagnosis1 were scored for the extent of inflammatory infiltrates or intimal hyperplasia as described3. Aortitis was defined by CTA as concentric thickening of the aortic wall ≥2mm. TABs were categorized according to the extent of inflammatory infiltrates (inflammation limited to adventitia vs transmural inflammation) and the degree of intimal hyperplasia. The latter was considered mild/moderate or severe depending on the ratio between the maximal thickness of the intima layer and the distance between the center of the lumen and the internal elastic lamina (75%). Fisher exact test was used for statistical analysis.ResultsBetween November 2006 and June 2013, 51 patients diagnosed with biopsy-proven GCA were included in a CTA-based screening protocol for LVV. Overall, aortitis was detected by CTA in 34 (66.7%) of cases. Inflammation limited to the adventitia was observed in 10 (19.6%) of cases and transmural inflammation in 41 (80.4%). Mild/moderate intimal hyperplasia was observed in 17 (33.3%) biopsies and severe intimal hyperplasia in 34 (66.7%). CTA-detected aortitis was observed in 27 (79.4%) of patients with transmural inflammation compared with 7 (70%) of patients with inflammation limited to the adventitia (p=1.00). Aortitis was seen in 23 (67.6%) of patients with severe intimal hyperplasia compared to 11 (64.7%)of patients with mild/moderate neointima formation (p=1.00).ConclusionsAlthough the limited size of