Updated for the first time in 30 years, the ACR "Vasculitis Classification Standard" is here!

*It is only for medical professionals to read for reference, striving to be a waver who masters the new classification standard.
In 1990, the sensitivity of the American College of Rheumatology (ACR) classification standard has dropped significantly in the past 30 years
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With the deepening of the understanding of the pathophysiology of vasculitis, and the innovation and application of related clinical diagnostic methods, the revision of the classification criteria for primary vasculitis has also been put on the agenda
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At the 2021 ACR Annual Conference (ACR 2021) that ended not long ago, Professor Raashid Luqmani of the University of Oxford Rheumatology and Dr.
Peter C Grayson of the National Institutes of Health The new classification standard of inflammation" was discussed
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In order to "integrate with international cutting-edge information and combine Chinese clinical practice" with the rheumatology and immunology department, the medical profession and 19 experts from the Youth Committee of the Chinese Medical Association Rheumatology Branch have brought a two-day project very quickly, relatively comprehensively and in depth.
Interpretation of the ACR 2021 live broadcast
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In this issue, Professor Liu Yanying from Beijing Friendship Hospital will take us into ACR 2021 and share the new classification criteria for ACR/EULAR vasculitis
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01 Dilapidated and new: Limitations of the 1990 ACR classification criteria.
According to the size of blood vessels, vasculitis is mainly divided into macrovasculitis (such as aortic arteritis and giant cell arteritis), medium vasculitis (such as polyarteritis nodosa and Kawasaki disease) and Small vasculitis [such as anti-neutrophil antibody (ANCA) related vasculitis]
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30 years have passed since the ACR classification standard formulated in 1990
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Statistics at the time believed that the sensitivity of the diagnostic criteria for giant cell arteritis (GCA) was 93.
5% and the specificity was 91.
2%; the sensitivity of the diagnostic criteria for aortic arteritis (TAK) was 90.
5% and the specificity was 97.
8%
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However, a 2017 study showed that one-third of doctors did not use this standard to correctly classify patients with vasculitis that meet the ACR criteria, and the sensitivity of the classification criteria in the modern population has been greatly reduced
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[1] Figure 1 The sensitivity of the 1990 ACR classification standard has decreased.
In addition, the 1990 ACR classification standard still has many limitations: 1.
1990 ACR classification standard was formulated before the widespread application of vascular imaging, and some of them played an important role in diagnosis.
The new diagnostic imaging technology has not been included in the diagnostic criteria; 2.
It is difficult for patients between the ages of 40 and 50 to distinguish between GCA and TAK; 3.
When the standard was established, only patients from North America were included, which has certain geographical limitations; 4 The standards are based on outdated methodology
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Figure 2 Limitations of the 1990 ACR classification standard Professor Liu Yanying then shared that for the current clinical trials, the 1990 ACR classification standard does not meet the results of modern clinical trials, so most of them no longer adopt the 1990 ACR classification standard.
The basis of the patient's diagnosis
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It's time to break the old and build the new and establish a new classification standard
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  02How to establish the classification standard? Experts take you step by step So, how was the new classification standard established? Professor Liu Yanying took the process of establishing the GCA and TAK classification standards as an example, and shared the six stages of the establishment of the GCA and TAK classification standards
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In the first stage, experts and scholars extensively included candidate projects, created a list of case reports, and counted the clinical characteristics of >1000 cases, as well as laboratory, pathological, and imaging related data
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In the second phase, an international prospective multi-center observational study of patients with vasculitis was carried out
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In the third and fourth stages, the zeros are turned into wholes, and the review of the external expert group is used as the gold standard for diagnosis, and the data of candidate projects is condensed
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In the fifth stage, scholars deduced the classification standards of GCA and TAK, and verified the classification standards in the sixth stage
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Figure 3 The process of establishing GCA and TAK classification standards 03 What are the new standards? Exciting content first look at the classification standard of giant cell arteritis Professor Liu Yanying pointed out that for GCA, the new standard emphasizes that this is a classification diagnostic standard rather than a diagnostic standard, and this standard is only applicable to patients who have been considered for diagnosis of macrovasculitis
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This standard has a necessary condition: the patient's age must be ≥50 years old
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Positive temporal artery biopsy or halo sign on temporal artery ultrasound is a very valuable indicator.
FDG-PET shows that the diagnosis of aortic activity in GCA also has certain characteristics.
These two are the indicators newly included in the new version of the standard, and the new classification standard The sensitivity reached 87% and the specificity reached 95%
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Figure 4 Classification standard of giant cell arteritis.
Classification standard of arteritis.
TAK classification standard was used for people aged ≤40 years old.
Patients in the age range of 40 to 50 years old were in the dilemma of "no class can be divided"
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In the new classification standard, the necessary conditions for the TAK classification standard are changed to patients aged ≤ 60 years old and have imaging evidence, which enlarges the age range
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The clinical criteria are consistent with the clinical manifestations of TAK patients.
The main consideration of imaging is the number of arteries involved in the patient
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The more arteries involved, the higher the score .

The sensitivity of this version of the standard has reached 94%, and the specificity is also as high as 99%
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Fig.
5 Classification criteria of aortic arteritis The diagnostic criteria of granulomatous polyangiitis Professor Liu Yanying shared that the criteria is also based on clinical manifestations, laboratory, imaging, and pathological examinations for scoring diagnosis.
Among them, the clinical symptoms are mainly ENT symptoms.
Mainly, nose-related symptoms such as epistaxis, ulcers, congestion or obstruction, or nasal septal defect or perforation are the most prominent, and the weight is 3 points
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In the laboratory examination, the positive cytoplasmic antineutrophil cytoplasmic antibody (cANCA) has a weight of 5 points, which can basically be considered for diagnosis
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However, Professor Liu Yanying specifically pointed out that before using the standard, alternative diagnoses similar to vasculitis should be excluded, that is, this standard should only be applied to patients who have been considered as vasculitis
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Pay special attention to the ear, nose and throat manifestations of lymphoma, fungal infection, and IgG-related diseases, and the classification criteria can be used after one by one is excluded
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In addition, perinuclear anti-neutrophil cytoplasmic antibody (pANCA) positive or anti-myeloperoxidase antibody (MPO) ANCA positive, serum eosinophil count ≥1×109/L are more useful for the diagnosis of other vasculitis Specificity is a deduction item of the standard
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Fig.
5 Classification criteria of granulomatous polyangiitis.
The diagnostic criteria for polyangiitis under the microscope, Professor Liu Yanying mentioned, this criterion is also used when considering the involvement of medium and small blood vessels in the patient and excluding alternative diagnosis similar to vasculitis
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If there are nose bleeding, ulcers, congestion or obstruction, or nasal septal defect, perforation and other nasal-related symptoms, an additional 3 points will be deducted
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Laboratory tests related to lungs and kidneys can also help diagnosis
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If pANCA or MPO ANCA is positive, 6 points will be added
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Professor Liu Yanying shared that although pANCA or MPO ANCA is more sensitive to polyangiitis under the diagnostic microscope, he has reservations about the weight of this item
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Figure 6 Classification criteria for polyangiitis under the microscope.
Diagnostic criteria for eosinophilic granulomatosis with polyangiitis.
The main symptoms of eosinophilic granulomatosis with polyangiitis are mainly above the respiratory symptoms, and the allergies are more prominent, and the nervous system-related symptoms also have a certain weight.

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Serum eosinophil count ≥ 1×109/L is a more characteristic indicator of the disease, with a weight of 5 points, and a biopsy showing extravascular eosinophil-based inflammation can also add 2 points
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Figure 7 Classification criteria for eosinophilic granulomatous polyangiitis Professor Liu Yanying pointed out that both GCA and TAK classification criteria are in the review process, and the final published version may be slightly different from the above two editions, but there are three classifications of ANCA-related vasculitis The standard article has been accepted and will not be changed
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Summary The new classification standard is used to diagnose the classification of diseases from clinical symptoms, laboratory, imaging, and auxiliary examinations.
It is more rigorous and more suitable for the development of modern auxiliary examinations
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The formulation of the new version of the standard is the largest vasculitis study to date, reflecting the views of representatives from different regions of the world on vasculitis
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In addition, the development of imaging technology has contributed to the upgrading of new standards, and the two complement each other and make progress together
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References: [1].
Seeliger B, Sznajd J, Robson JC, et al.
Are the 1990 American College of Rheumatology vasculitis classification criteria still valid?.
Rheumatology (Oxford).
2017;56(7):1154-1161.
doi : 10.
1093/rheumatology/kex075 Expert profile Professor Liu Yanying, deputy director of the Department of Rheumatology and Immunology, Beijing Friendship Hospital, chief physician, professor, and doctoral supervisor
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Doctor of Peking University School of Medicine, Postdoctoral of Karolinska University in Sweden
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Youth Committee of Rheumatology Branch of Chinese Medical Association, Youth Committee of Rheumatology and Immunology Physician Branch of Chinese Medical Doctor Association, Standing Committee and Secretary-General of IgG4 Related Diseases Group of Cross-Strait Medical and Health Association, and Standing Committee of Immune Purification and Cell Therapy Group of Internal Medicine Branch of Chinese Medical Association Deputy Secretary-General, National Doctors Association of Chinese Medical Doctors regularly assess specially-appointed experts
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He has presided over 9 projects including the National Key R&D Program (sub-project) of the Ministry of Science and Technology, the National Natural Science Foundation of China, and the Doctoral Fund of the Ministry of Education
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Published 71 articles in Chinese and English, including 41 articles by the first author or corresponding author
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