Monitoring Disease Activity in Patients With Takayasu Arteritis With the OMERACT Takayasu Ultrasound Score (OTUS) (MOTUS)

A Multicenter Prospective Observational Study on the Role of the OMERACT Takayasu Ultrasound Score (OTUS) in Monitoring Disease Activity in Patients With Takayasu Arteritis

This is a multicenter prospective observational study aimed at evaluating the role of an ultrasonographic score in monitoring disease activity in patients with Takayasu arteritis (TAK). Patients with active disease, either at new diagnosis or during relapse, will undergo serial vascular US assessments during follow-up according to routine clinical practice at each participating centers. For each patient, an OMERACT-derived US score (OTUS) will be calculated. This score was developed and preliminarily validated in previous phases of a multistep project endorsed by OMERACT (Outcome Measures in Rheumatology), an international initiative focused on the development and validation of outcome measures in rheumatology. The study hypothesis is that this score is sensitive to change over time and can be used to monitor disease activity and predict outcome in patients with TAK.

Study Overview

• Status: Not yet recruiting
• Conditions: Takayasu Arteritis (TAK)

Detailed Description

This is an observational study. The study concerns a diagnostic procedure (vascular US) that is part of normal clinical practice for patients with large-vessel vasculitis (LVV). The decision to perform vascular US in patients with TAK will remain independent from the decision to enroll the patient in the study. No investigational medicinal product or experimental device is involved. The procedure under study is an ultrasonographic scoring system derived from vascular US examinations of selected arterial segments in patients with TAK. Examinations will be performed according to standardized OMERACT protocols, including assessment of the common carotid, subclavian and axillary arteries, and the abdominal aorta. For each patient, an OMERACT-derived OTUS score will be calculated at each assessment. No comparator is mandated; however, clinical disease activity state and results from other imaging modalities (FDG-PET, MRA, CTA), when available as part of routine clinical care, will be collected for exploratory analyses. Study participation will last 24 months, during which patients will undergo serial US examinations at predefined follow-up visits as part of routine clinical monitoring. Vascular US is a non-invasive, radiation-free and contrast-free technique, already employed in standard clinical care and used here exclusively for observational purposes.

• Study Type: Observational
• Enrollment (Estimated): 100

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of patients with TAK and active disease, either newly diagnosed or experiencing a relapse. Active disease is defined as the presence of clinical signs and/or symptoms attributable to TAK, with or without elevation of inflammatory markers (ESR, CRP), and/or imaging evidence of active vasculitis (excluding US findings used in OTUS scoring).

Patients of any gender, aged ≥18 years, will be eligible.

Description

Inclusion Criteria:

• Age ≥18 years
• Male and female
• Diagnosis of TAK according to the 1990 ACR and/or 2022 ACR/EULAR classification criteria

• Active disease, defined as the presence of at least two of the following three domains:

  • Clinical domain: new onset or worsening of clinical signs and/or symptoms attributable to TAK;
  • Laboratory domain: elevation of inflammatory markers, defined as ESR and/or CRP above the upper limit of normal according to local laboratory standards, not attributable to causes other than TAK;
  • Imaging domain: imaging evidence of active vasculitis on modalities other than ultrasound, including FDG-PET, magnetic resonance angiography (MRA), or computed tomography angiography (CTA).
• Ability to undergo serial vascular ultrasound assessments during follow-up
• Provision of signed informed consent

Exclusion Criteria:

• Inability or contraindication to undergo vascular US
• Severe comorbidities limiting participation or follow-up
• Concomitant conditions that may confound ultrasound findings (e.g., significant atherosclerosis requiring intervention, complete occlusion of one of the arterial segments under investigation)
• Diagnosis of another rheumatologic disease
• Refusal or inability to provide informed consent

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in OTUS between active disease and remission in patients with Takayasu arteritis	Change in OTUS from baseline (active disease) to the first visit at which clinical remission is achieved, as determined by the treating physician (blinded to ultrasound results).	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24. For the primary endpoint only baseline → first remission visit will be analyzed.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To evaluate the agreement between OTUS-based activity assessment and NIH disease activity score	Cohen's kappa coefficient measuring agreement between OTUS-based disease activity classification and the National Institutes of Health (NIH) disease activity score for Takayasu arteritis (range 0-4, with higher scores indicating more active disease).	Baseline, month 1, month 3, month 6, month 12, month 18, month 24
Hazard ratio for time to relapse per unit increase in baseline OTUS score	Time to disease relapse (months), defined as recurrence of clinical signs and/or symptoms attributable to TAK with or without elevation of inflammatory markers, as judged by the treating physician. The hazard ratio per unit increase in baseline OTUS score will be estimated using Cox proportional-hazards regression.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Hazard ratio for time to vascular damage progression per unit increase in baseline OTUS score	Time to vascular damage progression (months), defined as new or worsening stenosis, occlusion, or aneurysm detected on CTA, MRA, or vascular US compared to baseline. The hazard ratio per unit increase in baseline OTUS score will be estimated using Cox proportional-hazards regression.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Odds ratio for successful glucocorticoid discontinuation per unit increase in baseline OTUS score	Proportion of patients achieving successful glucocorticoid discontinuation, defined as complete GC tapering without relapse for at least 3 consecutive months. The odds ratio per unit increase in baseline OTUS score will be estimated using logistic regression.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Hazard ratio for time to relapse per unit increase in OTUS change from baseline to month 3	Time to disease relapse (months), defined as recurrence of clinical signs and/or symptoms attributable to TAK with or without elevation of inflammatory markers, as judged by the treating physician. The hazard ratio per unit increase in OTUS change from baseline to month 3 (ΔOTUS) will be estimated using Cox proportional-hazards regression.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Hazard ratio for time to vascular damage progression per unit increase in OTUS change from baseline to month 3	Time to vascular damage progression (months), defined as new or worsening stenosis, occlusion, or aneurysm detected on CTA, MRA, or vascular US compared to baseline. The hazard ratio per unit increase in OTUS change from baseline to month 3 (ΔOTUS) will be estimated using Cox proportional-hazards regression.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Odds ratio for successful glucocorticoid discontinuation per unit increase in OTUS change from baseline to month 3	Proportion of patients achieving successful glucocorticoid discontinuation, defined as complete GC tapering without relapse for at least 3 consecutive months. The odds ratio per unit increase in OTUS change from baseline to month 3 (ΔOTUS) will be estimated using logistic regression.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
To assess the diagnostic ability of OTUS to detect clinical relapse during follow-up.	Diagnostic performance of OTUS for relapse detection	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Absolute OTUS score in treatment responders vs non-responders	Absolute OTUS score at each visit compared between clinical responders and non-responders to treatment, defined by physician global assessment. Difference between groups will be assessed using Mann-Whitney U test, with effect size estimation.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
OTUS change from baseline (ΔOTUS) in treatment responders vs non-responders	Change in OTUS score from baseline to each follow-up visit (ΔOTUS) compared between clinical responders and non-responders to treatment, defined by physician global assessment. Difference between groups will be assessed using Mann-Whitney U test, with effect size estimation.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Correlation between OTUS changes and clinical/laboratory markers of disease activity in Takayasu arteritis	Correlation between OTUS variation and: (i) ESR/CRP; (ii) clinical disease activity, as assessed by the Physician Global Assessment (PGA) of disease activity (0-10 visual analogue scale) and the National Institutes of Health (NIH) disease activity score for Takayasu arteritis.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Agreement between OTUS-based disease activity classification and Physician Global Assessment (PGA) in Takayasu arteritis	Cohen's kappa coefficient measuring agreement between OTUS-based disease activity classification and Physician Global Assessment (PGA) of disease activity, assessed on a 0-10 visual analogue scale.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Reference values for arterial wall thickness measured by vascular ultrasound in assessed arterial segments	Arterial wall thickness (mm) measured by standardized vascular ultrasound in the bilateral common carotid, subclavian and axillary arteries, and abdominal aorta. Descriptive statistics will be used to define reference values and proposed normality cut-offs.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Change in OTUS score over time stratified by treatment class	Change in OTUS score (continuous, expressed as ΔOTUS from baseline) over 24 months, compared across therapeutic classes (e.g., glucocorticoids alone, conventional immunosuppressants, biologics). Differences between treatment groups will be analyzed using linear mixed-effects models.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
Proportion of patients with changes in ultrasound lesion characteristics over time stratified by treatment class	Proportion of patients (%) showing new, resolved, or persistent elementary ultrasound lesions (macaroni sign, stenosis, occlusion) as defined by OMERACT criteria, compared across therapeutic classes. Differences between treatment groups will be described using proportions and compared using chi-square or Fisher's exact test as appropriate.	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.
To compare OTUS findings with FDG-PET, MRA and/or CTA obtained as part of routine clinical practice.	Concordance between OTUS and PET/MRA/CTA findings, both qualitative and quantitative (when available).	US performed at baseline, month 1, month 3, month 6, month 12, month 18, month 24.

Collaborators and Investigators

• Sponsor: IRCCS San Raffaele
• Collaborators: University Hospital Padova; Azienda USL Reggio Emilia - IRCCS

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): December 31, 2032
• Study Completion (Estimated): December 31, 2032

Study Registration Dates

• First Submitted: April 23, 2026
• First Submitted That Met QC Criteria: April 30, 2026
• First Posted (Actual): May 6, 2026

Study Record Updates

• Last Update Posted (Actual): May 11, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Skin Diseases; Skin Diseases, Vascular; Aortic Diseases; Vasculitis; Arteritis; Skin and Connective Tissue Diseases; Aortic Arch Syndromes; Takayasu Arteritis
• Other Study ID Numbers: TAK-MOTUS

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No