FRI0214 PERSISTENT LOW-GRADE FDG-PET VASCULAR INFLAMMATION IN REMITTED LVV-GCA PATIENTS IS ASSOCIATED TO A SIGNIFICANT HIGH RISK OF RELAPSE
Authors: R. Padoan, A. Tomelleri, M. Felicetti, C. Campochiaro, E. Baldissera, F. Crimì, P. Zucchetta, D. Cecchin, M. Picchio, L. Dagna, A. Doria, F. Schiavon
Journal: Annals of the Rheumatic Diseases (2020)

Background: Persistent low-grade vascular inflammation in giant cell arteritis (GCA) with large vessel involvement (LVV) treated patients could represent the expression of persistent subclinical disease activity or post-inflammatory vascular remodelling. Whether these findings have any impact on future vascular outcomes is still an unmet need. Objectives: To evaluate the frequency and evolution of FDG-PET low-grade vascular inflammation in remitted LVV-GCA patients. Methods: We included all consecutive patients classified as GCA with LVV involvement, with a minimum disease duration of 12 months and clinically remitted, who underwent to at least one PET/MR scan between January 2015 and January 2020. For each scan vessel’s metabolic activity was assessed using the Meller’s grading 1 . Low-grade inflammation was defined as Meller 1 and 2 (inferior or equal to liver), as reported in previous studies. Demographic and clinical data, as well as disease remission or flares, were recorded and compared to vascular metabolic activity. Results: In total 88 PET scans were performed in 54 LVV-GCA patients, predominantly female (77.8%), aged 68[7,8] years, with a regular BMI (23.9[2.8]) and with a long-standing disease (27[32.6] months). A subsequent PET/MR scan was available in 34 patients (median time between the two scans 9[6.3] months). At first PET examination, low-grade metabolic activity was reported in 68,5% of the cases, while complete remission in 15% and high metabolic activity in 25%. Comparing patients with low-grade vascular inflammation to those with complete remission (Meller 0), they had lower disease duration (28[25.9] vs 73[68] months, but without significance) and they were treated with higher daily prednisone dosage (5[3.8] vs 0[2.2], p=0.042). No significant differences were noted in age, acute phase reactants and type of treatment. Moreover, when compared to those with high metabolic activity (Meller 3), the latter had only significantly higher CRP levels (8.3[13.8] vs 4.1[3.9], p=0.03) and lower disease duration (19[20.6] vs 28[25.9] months, but without significance). While no significant differences were noted in age and type of treatment (both glucocorticoids and immunosuppressants). Among all patients with low-grade vascular inflammation, 81% of them underwent to steroids or immunosuppressants tapering due to clinical remission. At the subsequent PET examination, a worsening of metabolic activity (Meller 3) was found in 4/20 patients, with 1 clinical flare. While in 14/20 patients the subsequent PET revealed a persistent metabolic activity. Only in 2/20 there was a complete metabolic remission. Change or increase of the treatment regimen led to an improvement (Meller 0 or 1) in all the cases. Low-grade metabolic activity was associated with a significant increased risk of worsening/flare at the subsequent PET examination (RR 5.29[1.87-16.11], p=0.002). Conclusion: Low-grade vascular inflammation at PET examination is a common feature in remitted patients. It is associated with older age, lower disease duration and clinical remission. Treatment tapering is associated with an increased risk of worsening/flare. Further research is urgently needed to address this issue. References: [1]J. Meller et al., “Early diagnosis and follow-up of aortitis with [(18)F]FDG PET and MRI.,” Eur. J. Nucl. Med. Mol. Imaging, vol. 30, no. 5, pp. 730–6, May 2003. Disclosure of Interests: Roberto Padoan: None declared, Alessandro Tomelleri: None declared, Mara Felicetti: None declared, Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Elena Baldissera Speakers bureau: Novartis, Pfizer, Roche, Alpha Sigma, Sanofi, Filippo Crimì: None declared, Pietro Zucchetta: None declared, Diego Cecchin: None declared, Maria Picchio: None declared, Lorenzo Dagna Grant/research support from: Abbvie, BMS, Celgene, Janssen, MSD, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, SG, SOBI, Consultant of: Abbvie, Amgen, Biogen, BMS, Celltrion, Novartis, Pfizer, Roche, SG, and SOBI, Andrea Doria Consultant of: GSK, Pfizer, Abbvie, Novartis, Ely Lilly, Speakers bureau: UCB pharma, GSK, Pfizer, Janssen, Abbvie, Novartis, Ely Lilly, BMS, Franco Schiavon: None declared