PP6. OUTCOMES OF PATIENTS UNDERGOING TEMPORAL ARTERY BIOPSY OF LESS THAN 1 CM LENGTH FOR SUSPECTED GIANT CELL ARTERITIS

Background: The cornerstone of diagnosis in giant cell arteritis (GCA) is temporal artery biopsy (TAB). The conventional wisdom is that long length biopsies be obtained but no consensus exists on optimum length of biopsy. Objective: To examine the relationship between TAB length and 1 year outcomes in patients with suspected GCA. Methods: Clinical data was abstracted from the medical record on all patients undergoing TAB from 1994–2003. Data collected included age, gender, race, length of biopsy, histopathologic findings and outcomes including visual loss, stroke, myocardial infarction, polymyalgia rheumatica and death at 1 year. GCA diagnosis at 1 year was defined on clinical grounds or positive biopsy. False negative rate was defined as a negative biopsy but GCA at 1 year due to a repeat positive biopsy or clinical grounds. Results: 200 patients with TAB had complete follow-up data. The mean age was 69.6±11.0 years and 166/200 (83.3%) were females. The TAB length ranged from 0.1–2.4 cm, with a mean of 0.73±0.31 cm. 146/200 (73%) had a negative biopsy and 54/200 (27%) had a positive biopsy. There was no significant difference in mean biopsy length between patients with a positive (0.80±0.29) and negative biopsy (0.71±0.32, p = 0.0999). 2/143 (1.4%) patients had a false negative biopsy. Their TAB lengths were 0.6cm and 0.7cm, which approximated the mean length for the group. Taking a