VESS20 - Diagnosis of Giant Cell Arteritis in the Modern Era: Assessing the Role of Temporal Artery Biopsy

Objectives: Temporal artery biopsy (TAB) has long served as the diagnostic gold standard for Giant cell arteritis (GCA). However, in 2022, the American College of Rheumatology (ACR) updated the diagnostic criteria for GCA, incorporating more clinical features and imaging. This study evaluates the current value of TAB in diagnosing GCA within the context of updated classification criteria and evolving diagnostic practices.

Methods: We conducted a retrospective review of patients who underwent TAB for suspected GCA at a tertiary academic medical center over a 10-year period. Data collected included demographics, clinical factors, laboratory and imaging results, and biopsy findings. Univariate and bivariate analyses as well as receiver operating characteristic curves were calculated using Stata SE. Comparisons were performed between biopsy-positive and biopsy-negative groups based on the 1990 ACR criteria versus the updated 2022 ACR criteria.

Results: A total of 169 patients who underwent temporal artery biopsy were included (mean age 71 years; 64.5% female). Common comorbidities included hypertension (63.9%), diabetes (32.5%), and coronary artery disease (23.7%). Headache (45%) and vision changes (42%) were the most frequent indications. At biopsy, 88.2% were receiving corticosteroids, and 21.3% had biopsy-proven GCA. Biopsy results did not affect steroid management, with similar time to taper initiation and total steroid duration between positive and negative biopsies. Using 2022 criteria, 81.6% were diagnosed with GCA versus 65.1% using prior criteria. Biopsy was essential for diagnosis in 2.2% under new criteria compared with 17% under old criteria. Diagnosis of GCA was less reliant on biopsy using the new criteria (AUC 0.9891 vs. 0.9273). No significant complications were noted in TAB patients.

Conclusions: In our cohort of 169 patients, the overall biopsy positivity rate was modest, and steroid use at the time of biopsy did not significantly affect diagnostic yield. Use of adjunctive imaging, including ultrasound, was infrequent, underscoring the continued reliance on biopsy as a diagnostic tool. Under the new criteria, patients were more likely to be diagnosed with GCA compared with the old criteria. Three cases of GCA would have been missed without biopsy under the new criteria, compared with 16 cases under the old criteria, highlighting the decreasing importance of invasive biopsy to establish the diagnosis of GCA. At the same time, TAB remains a low-risk procedure. These findings suggest that the role of biopsy in the diagnostic algorithm for GCA may need further investigation. Further analyses are also critical to clarifying the impact of biopsy on medical therapy and outcomes.