Background/Purpose: While many manifestations of TA improve quickly after starting glucocorticoid therapy, vascular inflammation appears to persist.  To obtain more information about the duration of the histolopathologic changes after initiating glucocorticoids, we prospectively obtained second temporal artery biopsies in patients who had been treated for periods up to one year after first diagnostic biopsy.  The study was approved by Mayo Clinic institutional IRB.

Methods: 231 patients were seen at the Mayo Clinical for suspected TA and had temporal artery biopsies (TAB) (2004-2010).  In 89 (39%) TA was diagnosed.  40 of the 89 agreed to have a second TAB randomly assigned to 3, 6, 9, or 12 months after the first. The initial TAB was performed on the side clinically most suggestive of TA.  The second was performed on the opposite side. Histories and physical exams were performed prior to the biopsies. After biopsy oral glucocorticoid therapy was given at a median initial dose of 60 mg/day (range 30-80/day) for one month and then reduced gradually by approximately 10% of the daily dose per 2 weeks as tolerated according to the patients’ symptoms and findings. Histopathologic findings were retrospectively evaluated (in a blinded fashion) and documented by a cardiovascular pathologist (JJM).

Results: The cohort contained 28 women and the median age at diagnosis was 77 years (range 57-89). Manifestations at diagnosis were typical of TA and were similar among the four groups.  Overall 26 had jaw claudication, 15 PMR, and 6 ischemic optic neuropathy (AION).  Median hemoglobin for the 40 was 11.9 g/dl (range 9.3-14.1) and median ESR was 74 mm/hr (range 16-149).  Second TAB still showed vasculitis in 7/10 at 3 mo., 9/12 at 6 mo, 4/9 at 9 mo, and 4/9 at 12 mo, at which time median prednisone doses were, respectively, 25.0 mg/d, 9 mg/d, 10 mg/d, and 4.5 mg/d.    Overall those with a positive second TAB did not have a greater number of symptoms at diagnosis. However, all 6 pts with AION at diagnosis had vasculitis on second TAB (2 at 3 mo, 2 at 6 mo, 1 at 9 mo, and 1 at 12 mo.  Of those with a positive second TAB at 3 mo, 2 had headaches, 1 jaw claudication, and 1 scalp tenderness.  At 6 mo, 1 had headache and PMR, and at 9 and 12 mos, only 1 patient had headache. No patient developed any new manifestations of TA after therapy was started and no biopsy complications were observed.  Giant cells were present on the initial biopsy in 22 of the 40 cases.  Of those, 2 of 6 were still present at 3 mo, 6 of 8 were present at 6 mo, and none were found at 9 or 12 mos.  Additionally, giant cells were found on three follow up biopsies that were not present on the first biopsy, 1 at 3 mo, 1 at 6 mo, 1 at 9 mo.  Medial fibrosis was observed in 13 initial biopsies and 24 secondary biopsies with 6/10 at 3 mo, 9/12 at 6 mo, 5/9 at 9 mo, and 4/9 at 12 mo.

Conclusion: In a population of patients with TA treated with glucocorticoids, few reversible manifestations persisted after initiation of therapy, however, vasculitis continued in a diminishing number at 12 month follow-up. Medial fibrosis appears to correlate with chronicity of TA but is not always observed.  Giant cells may persist up to 6 months after initial biopsy but are rarely seen after that point.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/second-temporal-artery-biopsies-in-patients-with-temporal-arteritis-ta/