U.S. fast-track clinic models
The fast-track clinic models in the United States vary. Results of a survey of the U.S. clinics were presented as an abstract at the 2021 American College of Rheumatology annual meeting. Some centers have a vasculitis specialist obtain and interpret the imaging. At others, a vasculitis specialist refers patients to a VUS-trained rheumatologist to perform and interpret the test. Another approach is to have vasculitis specialists refer patients to ultrasound technicians trained in VUS, with a vascular surgeon interpreting the images and either a VUS-trained rheumatologist or vascular medicine specialist verifying the images.
The take-home message of that survey is that “ultrasound evaluation should be considered in the hands of experts, realizing that not everyone has that skill set, but if it is available, it’s a way to expedite diagnosis and it can be helpful in managing the GCA patient in an appropriate way, quicker than trying to schedule cross-sectional imaging,” said Massachusetts General’s Dr. Kohler, who is a coauthor of the abstract. “Certainly, cross-sectional imaging also plays an important role, but when it comes to confirming whether to continue with treatment or not for a very serious condition, ultrasound is a quick way to get the answer.”
In addition to the fast-track clinic at Massachusetts General, the survey included fast-track clinics at the University of Washington, Seattle; Brigham and Women’s Hospital, Boston; Loma Linda (Calif.) University; University of California, Los Angeles; and at a private practice, Arthritis and Rheumatism Associates in the Washington area.
Advantages of VUS vs. TAB
At Massachusetts General, some of the rheumatologists are trained to perform VUS. The rheumatologists also perform the clinical evaluation of suspected cases of GCA. The advantage of VUS, Dr. Kohler said, is that the answer is “right there”; that is, the imaging yields a diagnosis almost instantaneously whereas a biopsy must be sent to a lab for analysis.
“Since a lot of patients with suspected vasculitis may already come to us on steroid therapy, and if there’s a low probability or low suspicion for vasculitis, [VUS] actually confirms that, and we’re able to taper prednisone or steroids quickly rather than keep them on a prolonged course.”
Alison Bays, MD, MPH, of the department of rheumatology at the University of Washington, said that the advantages of avoiding biopsy aren’t to be overlooked. “Temporal artery biopsies are invasive and carry surgical risks, especially as many of our patients are elderly,” she told this news organization.
Dr. Alison Bays
“These patients occasionally refuse biopsy, but the acceptance of ultrasound is high,” Dr. Bays said. “Scheduling surgery can be more complicated, resulting in delays to biopsy and potentially higher rates of false negatives. Additionally, ultrasound has resulted in a higher rate of diagnosis with GCA as TAB misses large-vessel involvement.” The fast-track clinic at the university has evaluated 250 patients since it opened in 2017.
Dr. Bays and colleagues published the first United States study of a fast-track protocol using vascular sonographers. “Our group has demonstrated that fast-track clinics can rapidly and effectively evaluate patients, and we demonstrated a different method of evaluation using vascular sonographers rather than rheumatologists to do the vascular ultrasound,” she said. “It utilizes the familiarity vascular sonographers already have with imaging blood vessels.”
She added that the TABUL study in the United Kingdom in 2016 demonstrated that VUS yielded a savings of $686 (£484 as reported in the study), compared with TAB. “Further studies need to be done in the United States,” she said. “Beyond direct comparison of costs, reduction in steroid burden due to quick evaluation and diagnosis may carry additional benefits.”
At Brigham and Women’s Hospital, the division of rheumatology and the vascular section of the cardiology division collaborate on the GCA evaluation, said Sara Tedeschi, MD, MPH, codirector of the fast-track clinic there. Trained vascular technologists credentialed in the procedure and specifically trained in using VUS for evaluating arteritis perform the VUS. Cardiologists with a subspecialty in vascular medicine interpret the studies.
Dr. Sara Tedeschi
VUS patients have a rheumatology evaluation just before they have the ultrasound. “The rheumatology evaluation is then able to incorporate information from the VUS together with laboratory data, the patient’s history, and physical examination,” Dr. Tedeschi said.
“If the rheumatologist recommends a temporal artery biopsy as a next step, we arrange this with vascular surgery,” she said. “If the rheumatologist recommends other imaging such as MRA [magnetic resonance angiography] or PET-CT, we frequently review the images together with our colleagues in cardiovascular radiology and/or nuclear medicine.”
But in the United States, it will take some time for GCA fast-track clinics to become the standard, Dr. Tedeschi said. “Temporal artery biopsy may be faster to arrange in certain practice settings if VUS is not already being employed for giant cell arteritis evaluation,” she said.
Dr. Bays recognized this limitation, saying, “We are hoping that in the future, the American College of Rheumatology will consider vascular ultrasound as a first-line diagnostic test in diagnosis as rheumatologists and vascular sonographers gain familiarity over time.”
But that would mean that centers performing VUS for GCA would have to meet rigorous standards for the procedure. “With that, standardization of a protocol, high-quality equipment, and adequate training are necessary to ensure quality and reduce the chance of false-positive or false-negative results,” she said.
Dr. Chrysidis, Dr. Bays, and Dr. Tedeschi have disclosed no relevant financial relationships. Dr. Kohler is a board member of Ultrasound School of North American Rheumatologists.
A version of this article first appeared on Medscape.com.