A study of temporal artery biopsy for the diagnosis of giant cell arteritis.

Objective: This large, retrospective, multicenter study examines the Mayo Clinic experience with temporal artery biopsies over an 11-year period to help form guidelines that would lead to optimal performance of the technique. Methods: Pathology records were identified from all patients at all three Mayo Clinic sites (Rochester, MN; Jacksonville, FL; and Scottsdale, AZ) who underwent temporal artery surgery over an 11-year period, from January 1, 1994, to December 31, 2004. From each report, we extracted demographic information, the length of the temporal artery removed in the biopsy from each side, and the pathologic findings in each specimen. We used logistic regression to assess whether biopsy positivity may be associated with the following factors: biopsy length, age, sex, type (unilateral vs. bilateral), and year of study. Results: Our data set included 3817 temporal artery biopsies performed on 2539 patients at Mayo Clinic. Overall, 681 patients (27%) had a positive biopsy on at least one side. Biopsy length was uniformly noted to have no significant effect on biopsy positivity. Of the 603 patients with a bilateral biopsy, 43 (7%) had a negative initial biopsy followed by a positive result on the contralateral side. Conclusion: Our results support that one can recommend any length of biopsy, within the range our study, without affecting the rate of positivity. Furthermore, we conclude that if a unilateral biopsy is negative on frozen section, then we recommend a second biopsy on the contralateral side to avoid possible missed diagnoses. Key Points • Our paper is a large retrospective study over all 3 Mayo Clinic campuses investigating the association between temporal artery biopsy length and the positivity rate of biopsies. • We also determined the value of performing bilateral biopsies in which the first biopsy was negative on frozen section. • We believe the strength of our study is having one of the largest sample sizes of biopsies in the literature to date including 3817 biopsies. • The sum of our research supports that we found biopsy positivity is not a function of length and, second, bilateral biopsies diagnose up to 7% of disease not otherwise picked up by unilateral approaches. [ABSTRACT FROM AUTHOR]