Quantitative analysis of temporal artery contraction after biopsy for evaluation of giant cell arteritis

Abstract

Background: Although the degree of contraction of temporal artery biopsy specimens after formalin fixation has been previously reported to range from 6% to 13%, the degree of contraction before fixation has not been previously studied.The aim of this study was to quantify the postexcision (prefixation) contraction of temporal artery biopsy specimens and to determine the relationship between contraction and the result of the biopsy. Methods: All patients undergoing temporal artery biopsies from February 2003 through May 2004 were retrospectively reviewed. Contraction was determined by subtracting the in vivo and ex vivo lengths, then dividing the difference by the in vivo length to obtain a percentage of contraction. Statistical analysis was performed with the unpaired t test and Fisher exact test. Results: We reviewed 37 negative and 7 positive biopsies for giant cell arteritis (GCA). For specimens positive for GCA, the mean contraction was 12%, whereas for negative specimens, mean contraction was 22%. There was a significant difference in the contraction between the specimens positive and negative for GCA ( p = 0.009).The Fisher exact test revealed that GCA was positively associated with arterial contraction of less than 15% ( p = 0.002). Interpretation:The temporal artery can contract substantially after excision and before tissue fixation. GCA-positive specimens exhibit statistically less contractility than negative specimens.