Author Block: Carter W. Lim, Harrish Nithianandan, Vinay Kansal, Sangsu Han, James Farmer, Danah Albreiki

Author Disclosure Block: C.W. Lim: None. H. Nithianandan: None. V. Kansal: None. S. Han: None. J. Farmer: None. D. Albreiki: None.

Abstract Body:

Purpose: Temporal artery biopsy (TAB) is regarded as the gold standard investigation for confirming the clinical diagnosis of giant cell arteritis (GCA). Healing or healed arterial injury (HH) has been shown through serological markers to represent an intermediate between GCA-positive and GCA-negative TAB. The clinical outcomes of HH, however, have yet to be elucidated. The purpose of this study was to compare the rates of GCA-related adverse events in patients with an initial TAB diagnosis of HH to those with GCA-positive and GCA-negative diagnoses. 

Study Design: Retrospective cohort study Methods: This study examined 393 patients who underwent TABs for clinical suspicion of GCA at a single academic centre between 2009 and 2018. Rates of vision loss, stroke, aortitis, and aortic aneurysms (thoracic or abdominal) were compared between patients with histological TAB diagnoses of GCA-positive, HH, and GCA-negative. 

Results: 76 GCA-positive, 77 HH, and 240 GCA-negative TABs were identified. Rates of vision loss, including amaurosis fugax and decreased visual acuity, were not significantly different between the groups (p=0.46). Rates of aortic aneurysms in the GCA-negative, HH, and GCA-positive groups were 3%, 8%, and 12%, respectively. Rates of aortic aneurysms between GCA-negative and HH were not significantly different, whereas patients with GCA-positive TABs demonstrated significantly greater rates of aortic aneurysms (p=0.01). There was no association between pathology results and the rates of future stroke. Findings of aortitis (pathological or radiological) were exceedingly rare, with only two diagnoses made in the GCA-positive group and none in the HH and GCA-negative groups. 

Conclusions: TAB diagnosis of HH was not associated with significantly greater rates of vision or systemic adverse events compared to GCA-negative TABs. There was a dose-response trend in rate of aortic aneurysms between patients diagnosed with GCA-negative, HH, and GCA-positive TABs.