What is it about?

Giant cell arteritis (GCA) is an autoimmune disease of the blood vessels in the elderly that can cause lack of blood flow to various parts of the body, especially the eyes, with resultant blindness. The traditional "gold standard" test to confirm the clinical suspicion of GCA is a temporal artery biopsy, but this requires a 45 minute procedure and a scalp wound. As of late ultrasound has been increasingly proposed as a substitute for temporal artery biopsy. It is important to confirm the diagnosis of GCA, because the treatment of GCA is glucocorticoids (steroids) which have many potential side effects. European physicians seem to prefer ultrasound more than temporal artery biopsy. More than ninety percent of North American ophthalmologists, neurologists and rheumatologists in Ontario, Canada prefer a temporal artery biopsy.

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Why is it important?

In some areas it is may be difficult to obtain a temporal artery biopsy. Temporal artery biopsy is an invasive procedure. In order to obtain a specimen that is of adequate length, surgeons require appropriate training. Ultrasound is non-invasive, can be performed serially, and can also image other blood vessels in addition to the temporal artery. However ultrasound is also very dependent on the skill and experience of the operator. Also, on ultrasound other conditions such as atherosclerosis can give the false impression of GCA.

Perspectives

The TABUL study is frequently cited as support for ultrasound. Although the TABUL study performed excellent ultrasounds, the temporal artery biopsies were subpar. Few people know that in the TABUL study the "surgeon" was unable to find the artery 7.3% of the time and that 43% of the time when the artery was found, the specimen was too short to be of optimal use for the pathologist. With an experienced surgeon temporal artery biopsy is a straightforward procedure. In my opinion an experienced surgeon can find the temporal artery about 99% of the time, and obtain a specimen >=1 centimeter at least 95% of the time. Meta-analyses suggest that temporal artery biopsy is at least as sensitive if not more sensitive than ultrasound. Although temporal artery biopsy is time-consuming, and difficult to schedule, a tissue diagnosis (pathology) is the most reassuring for me. (For most surgeons there is little to no financial incentive to perform a temporal artery biopsy because the procedure pays very little) If an institution chooses to use ultrasound or MRI to diagnose GCA, I believe it prudent to correspond the results of the first fifty to one hundred cases with biopsy and imaging before relying solely on imaging.

Dr Edsel B Ing
University of Toronto

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This page is a summary of: Practice Preferences: Temporal Artery Biopsy versus Doppler Ultrasound in the Work-Up of Giant Cell Arteritis, Neuro-Ophthalmology, October 2019, Taylor & Francis, DOI: 10.1080/01658107.2019.1656752.
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