Questioning the Utility of Temporal Artery Biopsy in Giant Cell Arteritis: A Negative Biopsy May Facilitate Decision-making.

Abstract

We undertook a prospective study of adult patients undergoing TAB for GCA in Calgary. Consecutive, multicenter recruitment was performed over 2 years. Primary outcomes included initiation or discontinuation and duration of corticosteroids. Twenty-one TABs were performed in 20 patients. Nineteen percent of TABs were positive, and 71.4%, negative. In 9.5% of patients, accidental sampling of a vessel other than the superficial temporal artery occurred. Fifty-two percent of patients received steroids before TAB, of which the mean duration was 8.0 days for TAB+ (postive temporal artery biopsy result) patients and 8.4 days for TAB- (negative temporal artery biopsy result; P = 0.22) patients. Before TAB, the American College of Rheumatology score was 2.5 for TAB+ patients and 2.4 for TAB- (P = 0.74). Postbiopsy, the American College of Rheumatology score was 3.5 for TAB+ patients (therefore reaching diagnostic threshold of 3) but remained 2.4 for TAB- (P = 0.02). TAB+ patients were treated for 352.3 days, whereas TAB- patients for 16.7 days (P = 0.29). Complications were more likely with long-term (>6 weeks) steroids (P = 0.17). In patients with a low suspicion of GCA, a negative TAB helps bolster physician confidence and leads to a shorter steroid duration.