Vascular ultrasound may offer first-line alternative for diagnosing giant cell arteritis
Vascular ultrasound, using high-end equipment and optimized settings, may be an effective replacement for temporal artery biopsy as a first-line diagnostic tool in patients with suspected giant cell arteritis, according to a Danish study.
“Temporal artery biopsy is considered the diagnostic gold standard for giant cell arteritis,” Stavros Chrysidis, PhD, of the University of Southern Denmark, Hospital of South West Jutland, and colleagues wrote in The Lancet Rheumatology. “However, use of temporal artery biopsy in routine care has been questioned because it is an invasive procedure and its performance and subsequent pathological evaluation can delay diagnosis, and it has low sensitivity.”
“The European Alliance of Associations for Rheumatology (EULAR) recommends ultrasound as a first-line diagnostic test for patients with predominantly cranial symptoms of giant cell arteritis if expert ultrasonography is promptly available,” they added. “However, few studies in the meta-analysis on which these recommendations were based had a low risk of bias. Limitations of these studies were that the ultrasound diagnosis was made by an investigator not masked to clinical data, the final diagnosis was influenced by the ultrasound results, and temporal artery biopsy was not done in all patients.”
To analyze the diagnostic accuracy of ultrasound in cases of suspected GCA, Chrysidis and colleagues conducted a prospective, multicenter, non-interventional cohort study of patients at three hospitals. Participants aged 50 years or older with clinically suspected extracranial or cranial GCA underwent a bilateral ultrasound of the temporal, facial, common carotid, and axillary arteries.
The participants then underwent a temporal artery biopsy within 7 days of starting corticosteroid treatment. The researchers followed up on the participants at 6 months, during which time clinicians collected data from all examinations, allowing them to make a full diagnosis at the end of that period. The researchers’ diagnostic criterion standard was a confirmed diagnosis after 6 months of follow-up.
A total of 118 patients were screened for inclusion between April 1, 2014, and July 31, 2017, of whom 106 underwent ultrasound and temporal artery biopsy and were included in the analysis.
Temporal artery biopsy was positive in 43% of the included patients. Ultimately, 58% of the included patients had a clinically confirmed diagnosis of GCA at 6 months, resulting in a sensitivity of 74% (95% CI, 62-84) and a specificity of 100% (95% CI, 92-100) for temporal artery biopsy.
Further, cranial artery ultrasound was positive in all participants who had a positive temporal artery biopsy. Among the 12 patients who were positive by ultrasound and negative by temporal artery biopsy, seven — or 58% — were confirmed to have large-vessel GCA through other imaging methods. The sensitivity of ultrasound GCA diagnosis was 94% (95% CI, 84-98), with a specificity of 84% (95% CI, 70-93).
A logistic regression analysis confirmed that ultrasound was the strongest baseline predictor for a clinically confirmed GCA diagnosis at 6 months, with a crude odds ratio of 76.6 (95% CI, 21-280) and an adjusted — for sex and age — OR of 141 (95% CI, 27-743).
“Ultrasound assessment of vasculitis as the initial diagnostic test in individuals who have been referred to specialists because of clinically suspected giant cell arteritis was the strongest independent predictor for the final giant cell arteritis diagnosis at 6 months of follow-up,” Chrysidis and colleagues wrote.
“Vascular ultrasound of cranial arteries and large vessels by trained ultrasonographers using high-end equipment and optimized settings have high diagnostic sensitivity and specificity in patients with suspected giant cell arteritis, and it might replace invasive temporal artery biopsy as a first-line diagnostic method,” they added. “In the future, implementation studies might be needed to test the applicability of these methods to health care internationally.”