Temporal artery biopsy: A technical guide and review of its importance and indications

Giant cell temporal arteritis: a clinicopathological study with emphasis on unnecessary biopsy

Introduction

Temporal artery (TA) biopsy is commonly used for the diagnosis of giant cell arteritis (GCA). However, a positive biopsy is no longer mandatory for diagnosis. This study aims to correlate the histopathological findings of TA biopsies in suspected cases of GCA to the clinical presentation in an ophthalmic tertiary eye care center to draw useful conclusions and advocate the possible implementation of guidelines for TA biopsy.

Methods

Data was collected from patients' medical records including, demographics, clinical data, and histopathological findings and diagnosis. The 2022 American College of Rheumatology/ European Alliance of Associations for Rheumatology (ACR/EULAR) criteria have been used and partially adopted as a guide to compare the variables between TA biopsy-positive and negative groups as well as the TA biopsy-positive group and the group of patients with TA biopsy showing atherosclerosis.

Results

Out of the total 35 patients who underwent a TA biopsy during the period of 23 years, 22.9% of patients had histopathological findings consistent with GCA and 42.9% had TA atherosclerotic changes, while the remaining 34.3% had histologically unremarkable TA. The mean age of all patients was 66 ± 10.9 years. Slightly more than half were females (54.3%) and the remaining were males (45.7%). In the group with positive TA biopsies, the mean age was 71 ± 8.4 years with a higher female predominance (female-to-male ratio of 5:3). The mean diagnostic clinical score used in our study was higher (7.5 ± 2.33) in the GCA-positive group when compared to the other groups with statistical significance (mean of 4.85 ± 2.01 in patients with overall GCA-negative biopsies and 5.13 ± 2.10 in the group with atherosclerosis). Other three clinical variables that were found to be statistically significant in the GCA biopsy-positive group were scalp tenderness, jaw claudication, and optic nerve pallor.

Discussion

The mean age (71 ± 8.4 years) and the female predominance of GCA in our group of patients with positive TA biopsy (62.5%) was like other reports. In our study 22.9% of performed TA biopsies over the period of the study were positive confirming the diagnosis of GCA on histological exam, which was similar to another report and is considered to be relatively low. The incorporation of increased clinically focused assessments and algorithms, with the aid of the ACR/EULAR criteria, may decrease the frequency of TA biopsies that carries unnecessary cost and risk of procedure-related morbidity. We highly recommend applying the age of ≥ 50 years as an initial criterion for diagnosis, followed by the consideration of the statistically significant clinical features: scalp tenderness, jaw claudication, and optic nerve pallor.

Temporal artery biopsy for suspected giant cell arteritis: A mini review

Giant cell arteritis (GCA) is a granulomatous inflammation involving medium and large vessels that can lead to serious clinical manifestations associated with tissue ischemia. Temporal artery biopsy (TAB) is currently the gold standard method for the diagnosis of GCA, with a specificity of 100% and a sensitivity of 77%. However, the false-negative rate for TAB ranges from 9% to 61%. False negatives may be related to the timing of biopsy, the length of specimen, and the existence of "skip lesions." We reviewed the relevant evidence for methods to improve the sensitivity and reduce the false-negative rate for TAB. To reduce the false-negative rate for TAB, it is recommended to perform TAB within 1 week of starting corticosteroid therapy. Although there is currently no consensus, we suggest that the temporal artery is cut to a length of 20‒30 mm and to prepare serial pathological sections. It is necessary to attach great importance to patients suspected of having GCA, and complete TAB should be performed as soon as possible while starting corticosteroid therapy promptly. We also discuss the clinical value of non-invasive vascular imaging technologies, such as DUS, CTA, MRA, and 18F-FDG-PET/CT, as auxiliary methods for GCA diagnosis that could partially replace TAB.

Use of high-plex data provides novel insights into the temporal artery processes of giant cell arteritis

Objective

To identify the key coding genes underlying the biomarkers and pathways associated with giant cell arteritis (GCA), we performed an in situ spatial profiling of molecules involved in the temporal arteries of GCA patients and controls. Furthermore, we performed pharmacogenomic network analysis to identify potential treatment targets.

Methods

Using human formalin-fixed paraffin-embedded temporal artery biopsy samples (GCA, n = 9; controls, n = 7), we performed a whole transcriptome analysis using the NanoString GeoMx Digital Spatial Profiler. In total, 59 regions of interest were selected in the intima, media, adventitia, and perivascular adipose tissue (PVAT). Differentially expressed genes (DEGs) (fold-change > 2 or < -2, p-adjusted < 0.01) were compared across each layer to build a spatial and pharmacogenomic network and to explore the pathophysiological mechanisms of GCA.

Results

Most of the transcriptome (12,076 genes) was upregulated in GCA arteries, compared to control arteries. Among the screened genes, 282, 227, 40, and 5 DEGs were identified in the intima, media, adventitia, and PVAT, respectively. Genes involved in the immune process and vascular remodeling were upregulated within GCA temporal arteries but differed across the arterial layers. The immune-related functions and vascular remodeling were limited to the intima and media.

Conclusion

This study is the first to perform an in situ spatial profiling characterization of the molecules involved in GCA. The pharmacogenomic network analysis identified potential target genes for approved and novel immunotherapies.

Temporal artery biopsy

Giant cell arteritis is a common vasculitis in patients over the age of 50 years old. If not promptly recognized and aggressively treated with high-dose glucocorticoids, ischemia resulting in permanent vision loss or stroke can occur. Yet, the treatment with high-dose glucocorticoids over a long period of time can be problematic in this particular patient population given their age and associated comorbidities. Temporal artery biopsies (TAB) are an important diagnostic tool to evaluate patients with suspected giant cell arteritis. Herein, we explore indications for TAB and practical points in obtaining a TAB based on available evidence. We review the surgical procedure itself and associated complications. Lastly, we examine common pathological findings and considerations of alternative diagnoses.