Vessel inflammation and morphological changes in patients with large vessel vasculitis: a retrospective study

Association of PET vascular activity score with Takayasu's arteritis angiographic progression

OBJECTIVE

Arterial wall Fluorodeoxyglucose (FDG) uptake can reflect vascular inflammation in Takayasu's arteritis (TAK); however, its association with vascular prognosis remains unclear. This study assessed the predictive efficacy of the PET vascular activity score (PETVAS) for vascular prognosis and whether FDG uptake in specific arterial territories was associated with angiographic progression in TAK.

METHODS

Patients with TAK from a prospective observational cohort who underwent 18F-FDG PET/CT and serological tests at baseline were included. Magnetic Resonance Angiography and/or Contrast-Enhanced Ultrasound were conducted at baseline and every six months during follow-up. The PETVAS was calculated. New/aggravated lesions were considered as angiographic progression.

RESULTS

The imaging evaluation included 1,353 arterial territories from 123 patients. The baseline PETVAS was positively correlated with Erythrocyte Sedimentation Rate (ESR), serum IL-6, and Platelet. Angiographic progression was noted in 45 patients (36.6%) with 72 territories (5.3%) during 30 (18-72) months of follow-up. Of these, 19 (42.2%) had baseline PETVAS > 15, including 84.2% (16/19) naïve cases and 78.9% (15/19) with ESR ≥ 30 mm/h. Multivariate Cox proportional hazards regression analysis adjusted for age and sex showed baseline PETVAS > 15 (HR 1.93; 95% CI, 1.01-3.68; p = 0.04) an independent predictor of angiographic progression.

CONCLUSION

Baseline PETVAS > 15 was an independent predictor of angiographic progression in TAK. Baseline FDG uptake in specific arterial territories did not correlate with vascular progression. Our study provides a feasible PET/CT-based predictive marker for vascular progression in TAK and underscores the importance of regular imaging follow-up to monitor disease outcomes.

CLINICAL TRIAL NUMBER

Not applicable.

Positron Emission Tomography in Takayasu Arteritis: A Review Including Patterns of Vascular Involvement Across Modalities and Regions

Takayasu arteritis (TAK) is a rare, chronic large-vessel vasculitis that predominantly affects the aorta and its major branches. Early and accurate diagnosis remains essential to prevent irreversible vascular damage and organ dysfunction. Positron emission tomography/computed tomography (PET/CT) has emerged as a valuable imaging modality for detecting active vascular inflammation in TAK. Using 18F-fluorodeoxyglucose (18F-FDG), PET/CT enables the assessment of metabolic activity in inflamed arterial walls, supporting both initial diagnosis and disease monitoring. Compared with conventional imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT), PET/CT provides functional data correlated with inflammatory activity rather than solely anatomical changes. Recent studies have highlighted its utility in distinguishing active from chronic disease, predicting relapse, and evaluating treatment response. This review summarizes the role of PET/CT in TAK, addressing its advantages, patterns of vascular involvement, limitations, and future perspectives. Vascular lesions identified using PET/CT do not always align with those detected by other imaging modalities, with PET/CT demonstrating superiority in revealing aortic inflammation potentially overlooked by alternative techniques. Further research is needed to establish whether PET/CT-based vascular involvement patterns, rather than conventional angiographic findings, can help identify disease subtypes of TAK.

Impact of conventional and biological disease-modifying anti-rheumatic drugs on arterial lesions in Takayasu arteritis

BACKGROUND

The definition of Takayasu arteritis (TAK) remission and disease activity is still unclear. Vascular imaging is an essential tool for following-up patients. Herein, we aimed to compare the evolution of vascular lesions (i.e. vessel wall thickening and stenosis) under conventional cDMARDs relatively to biological DMARDs (bDMARDs) in TAK patients followed with the same CT angiography modalities.

METHOD

We compared 75 lines of therapy in TAK patients who received cDMARDs (n = 40 lines) and bDMARDs (n = 35 lines) using CT angiography. We established 1-3 main target vessels with vessel wall thickening and/or stenosis. Every targeted vessel had its thickness and its lumen diameter measured at the initiation of immunosuppressive treatment and at 12 months.

RESULTS

We observed an overall reduction in arterial wall thickness in 73% of cases and 31% had >25% relative decrease in the wall thickness. Using a linear mixed effects model, first-line immunosuppressive therapy (P = 0.012) and bDMARDs relatively to cDMARDs (P = 0.026) were independently associated with vessel wall thickness reduction in TAK. Thirty-eight percent of the stenotic vessels had a > 25% relative increase in lumen diameter under immunosuppressive therapy. The relative increase >25% in lumen diameter was noted in 56% vs 17% with bDMARDs compared with cDMARDs.

CONCLUSION

Immunosuppressive treatments can reduce arterial wall thickness and widen lumen diameter in TAK. bDMARDs seem to be more effective than cDMARDs to improve arterial lesions in TAK.

Does tocilizumab eliminate inflammation in GCA? A cohort study on repeated temporal artery biopsies

BACKGROUND

Vascular inflammation persists in temporal artery biopsy (TAB) of giant cell arteritis (GCA) patients even after prolonged glucocorticoid (GC) therapy. We aimed to evaluate the histological impact of adding tocilizumab (TCZ) to GCs.

METHODS

We enrolled all consecutive GCA patients with an inflammed TAB at diagnosis who were treated with TCZ and GCs for ≥6 months and followed from December 2017 to December 2023. Within 2 weeks, all patients underwent a second TAB, positron emission 18-fluorodeoxyglucose tomography/CT (PET/CT) and vessel colour Doppler ultrasonography (CDUS). Results were compared with pretreatment findings.

RESULTS

13 patients repeated TAB after a median TCZ treatment of 2.4 years (Q1-Q3: 1.2-3.9 years). The first TAB showed transmural inflammation (TMI) in 11/13 patients (84.6%), inflammation limited to adventitia (ILA) in one patient (7.7%) and small vessel vasculitis (SVV) in another (7.7%). On repeated TABs, five patients (38.5%) still showed some degree of inflammation. Among the 11 patients with initial TMI, 2 had ILA, 1 had TMI, 1had SVV and 1 had vasa vasorum vasculitis at the second TAB. Nine patients had active vasculitis at baseline PET/CT, and three (33.3%) still showed activity at the last PET/CT, with a relevant reduction in mean PET vascular activity score (-6.5; 95% CI 1.54 to 11.45; p=0.017). The repeated quantitative CDUS revealed altered parameters suggestive of vasculitis in temporal arteries in about one-third of the patients.

CONCLUSION

Our study, using pathological and imaging assessments, revealed that after TCZ and GCs, over one-third of patients still presented with vascular inflammation.

Development of the Takayasu Arteritis Integrated Disease Activity Index

OBJECTIVE

Accurate clinical assessment of disease activity in Takayasu arteritis (TAK) can be challenging. 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) can directly measure vascular inflammation. This study details the development of a new type of disease activity index called the Takayasu's Arteritis Integrated Disease Activity Index (TAIDAI).

METHODS

Clinical symptoms for TAIDAI were identified from a literature review. Each symptom was paired with FDG-PET findings in corresponding arterial territories. Constitutional symptoms were paired with acute phase reactant levels. One point was given for each clinical symptom paired with supporting FDG-PET or laboratory abnormalities and summed into the TAIDAI score. A TAIDAI of ≥1 defined active disease. To assess performance of TAIDAI, face validity, content validity, and sensitivity to change were evaluated within a prospective observational cohort study of patients with TAK.

RESULTS

Seventeen clinical symptoms were paired with imaging or laboratory abnormalities. In a cohort of 96 patients contributing 204 study visits, TAIDAI showed excellent sensitivity (96.3%) and good specificity (79.2%) compared to physician's clinical assessment. TAIDAI significantly correlated with physician global assessment, PET Vascular Activity Score, patient global assessment, and acute phase reactant levels. In patients treated with either tumor necrosis factor inhibitors or tocilizumab, a TAIDAI of 0 was achieved in 21 (91%) of 23 patients who met a predefined definition of clinical response.

CONCLUSION

TAIDAI is new type of disease activity index in TAK in which clinical symptoms are integrated with specific laboratory and imaging findings. TAIDAI should be validated in future randomized controlled trials in TAK.

Effectiveness and safety of a 26-week taper regimen of glucocorticoid in GCA patients: Results from a prospective cohort study

OBJECTIVES

To assess the effectiveness and safety of the 26-week tapering regimen of glucocorticoids (GC) used in the GiACTA trial in a prospective cohort of treatment-naive, biopsy-proven GCA patients.

METHODS

Patients with a new diagnosis of biopsy-proven GCA enrolled in the GC arm of the START project (molecular stratification of patients with GCA to tailor GC and tocilizumab therapy) were included. All patients were treated with the 26-week taper regimen of GC used in the GiACTA trial. The primary endpoint was the rate of relapse-free remission at week 52. The secondary endpoints were the proportion of patients with incident aortic damage, cumulative GC doses and GC-related adverse events (AE).

RESULTS

22 patients were included between December 2018 and February 2022. At week 52, 10 patients (45 %, 95 % CI 24-68) were in relapse-free remission. After a median (IQR) follow-up of 35 (22-40) months, 7 patients (32 %, 95 % CI 14-55) were in relapse-free remission. 18 patients with baseline large-vessel imaging underwent CT angiography at the end of the follow-up. No patients had evidence of new aortic dilation, significant progression of aortic damage or large vessel stenosis. 15/22 patients (68 %) had at least one relapse during follow-up. No patients developed visual or cerebrovascular manifestations during relapses. 15/22 (68 %) patients had at least one GC-related AE.

CONCLUSIONS

A 26 week taper regimen of GC was effective and safe in inducing and maintaining remission in a sizeable proportion of newly diagnosed GCA patients. However, the frequency of GC-related adverse events was high.

Treatment of giant cell arteritis with ultra-short glucocorticoids and tocilizumab: the role of imaging in a prospective observational study

OBJECTIVES

To assess the impact of tocilizumab (TCZ) monotherapy after ultra-short-pulse glucocorticoids (GCs) on clinical manifestations, and vessel inflammation and damage in large vessel-GCA (LV-GCA).

METHODS

In this prospective observational study, we enrolled patients with active LV-GCA. All patients received 500 mg per day i.v. methylprednisolone for three consecutive days and weekly s.c. TCZ injections from day 4 until week 52. PET/CT was performed on all patients at baseline and at weeks 24 and 52. The primary end points were the reduction in the PET vascular activity score (PETVAS) at weeks 24 and 52 compared with baseline, and the proportion of patients with relapse-free remission at weeks 24 and 52. The secondary end point was the proportion of patients with new aortic dilation at weeks 24 and 52.

RESULTS

A total of 18 patients were included (72% female, mean age 68.5 years). Compared with the baseline value, a significant reduction in the PETVAS was observed at weeks 24 and 52, mean (95% CI) reductions -8.6 (-11.5 to -5.7) and -10.4 (-13.6 to -7.2), P = 0.001 and 0.002, respectively. The proportion of patients with relapse-free remission at weeks 24 and 52 was 10/18 (56%, 95% CI 31-78) and 8/17 (47%, 95% CI 23-72), respectively. At weeks 24 and 52, no patient had shown new aortic dilation. However, 4 patients who had shown aortic dilation at baseline showed a significant increase in aortic diameter (≥5 mm) at week 52.

CONCLUSION

TCZ monotherapy after ultra-short-pulse GCs controlled the clinical symptoms of GCA and reduced vascular inflammation.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT05394909.

The role of PET/CT in disease activity assessment in patients with large vessel vasculitis

PURPOSE OF REVIEW

The aim of this article was to review the recent contributions on the role of PET in assessing disease activity in patients with large-vessel vasculitis (giant cell arteritis and Takayasu arteritis).

RECENT FINDINGS

18 FDG (fluorodeoxyglucose) vascular uptake in large-vessel vasculitis at PET shows moderate correlation with clinical indices, laboratory markers and signs of arterial involvement at morphological imaging. Limited data may suggest that 18 FDG (fluorodeoxyglucose) vascular uptake could predict relapses and (in Takayasu arteritis) the development of new angiographic vascular lesions. PET appears to be in general sensitive to change after treatment.

SUMMARY

While the role of PET in diagnosis large-vessel vasculitis is established, its role in evaluating disease activity is less clear-cut. PET may be used as an ancillary technique, but a comprehensive assessment, including clinical, laboratory and morphological imaging is still required to monitor patients with large-vessel vasculitis over time.

Association of 18 F-Fluorodeoxyglucose-Positron Emission Tomography Activity With Angiographic Progression of Disease in Large Vessel Vasculitis

OBJECTIVE

To assess whether vascular activity seen on 18 F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scan is associated with angiographic change in large vessel vasculitis (LVV).

METHODS

Patients with LVV were recruited into a prospective cohort. All patients underwent magnetic resonance angiography or computed tomography angiography and FDG-PET imaging. Follow-up imaging using the same imaging modalities was obtained ≥6 months later per a standardized imaging protocol. Arterial damage, defined as stenosis, occlusion, or aneurysm, and corresponding FDG uptake were evaluated in 17 arterial territories. On follow-up, development of new lesions was recorded, and existing lesions were characterized as improved, worsened, or unchanged.

RESULTS

A total of 1,091 arterial territories from 70 patients with LVV (38 patients with Takayasu arteritis, 32 patients with giant cell arteritis) were evaluated. Over a median 1.6 years of follow-up, new lesions developed only in 8 arterial territories in 5 patients with Takayasu arteritis. Arterial lesions improved in 16 territories and worsened in 6 territories. Most arterial territories that did not have vascular activity on FDG-PET scan at baseline had no angiographic change over the follow-up period (787 [99%] of 793). Few territories with baseline FDG-PET activity had angiographic change over time (24 [8%] of 298), but of the territories that developed angiographic change, 80% had FDG-PET activity at baseline. Within the same patient, an arterial territory with baseline FDG-PET activity had significantly increased risk for angiographic change compared to a paired arterial territory without FDG-PET activity (odds ratio 19.49 [95% confidence interval 2.44-156.02]; P < 0.01). Concomitant edema and wall thickening further increased risk for angiographic change.

CONCLUSION

Development of angiographic change was infrequent in this cohort of patients with LVV. A lack of baseline FDG-PET activity was strongly associated with stable angiographic disease. In cases of angiographic progression, change was preceded by the presence of FDG-PET activity.