Effect of Temporal Artery Biopsy Length and Laterality on Diagnostic Yield

Background: Giant cell arteritis (GCA) is the most common vasculitis in adults and is associated with significant morbidity and mortality. Temporal artery biopsy (TAB) remains the gold standard for diagnosis in the United States; however, practices vary in the length of artery obtained and whether bilateral simultaneous biopsies are obtained. Methods: Retrospective chart review of all TABs performed at the Johns Hopkins Wilmer Eye Institute between July 1, 2007, and September 30, 2017. Results: Five hundred eighty-six patients underwent TAB to evaluate for GCA. Of 404 unilateral biopsies, 68 (16.8%) were positive. Of 182 patients with bilateral biopsies, 25 (13.7%) had biopsies that were positive and 5 patients (2.7%) had biopsies that were discordant, meaning only 1 side was positive. There was no significant difference in the average postfixation length of positive and negative TAB specimens (positive mean length 1.38 ± 0.61 cm, negative mean length 1.39 ± 0.62 cm, P = 0.9). Conclusions: There is no significant association between greater length of biopsy and a positive TAB result in our data. Although the rate of positive results was not higher in the bilateral group compared with the unilateral group, 2.7% of bilateral biopsies were discordant, similar to previously published rates. Overall, this suggests that initial bilateral biopsy may increase diagnostic yield, albeit by a small amount.