Summary
Kidney and lung involvement constitute key disease features and largely confer higher disease burden and mortality in patients with ANCA-associated vasculitis (AAV). Lung biopsy is only performed in a minority of cases and diagnosis of lung involvement relies on clinical and imaging findings. As such, evaluation of CT scans is of utmost importance. In this study the authors aimed to describe individual pulmonary patterns in AAV subtypes and correlate these findings to major clinical outcomes.

In a retrospective analysis of AAV patients with Granulomatosis with Polyangiitis (GPA) or Microscopic Polyangiitis (MPA) at University Hospital Aachen the authors screened 258 patients treated between 1999 and 2020. The patients were (re)classified based on the current ACR/EULAR criteria from 2022, and after exclusion of patients with insufficient clinical and/or follow-up informations, they included 94 AAV patients in the analysis. Lung involvement was present in 44 cases with available CT scans. In the subcohort of patients with pulmonary affection, treatments with Rituximab and Cyclophosphamide were used almost equally. The median follow-up was over 37 months.

It was shown that ground-glass opacities were seen in 66,7% of patients with relapsing disease (and only 18,8% among non-relapse patients; OR 8,67, p=0,004). The same trend was observed for the presence of pleural effusion (OR 6,07, p=0,023), whereas nodules occurred less frequently in relapsing patients (OR 0,15, p=0,009).

Impact on Patient Treatment and Future Perspectives
This study sheds a more detailed view on specific CT patterns in relation to clinical outcomes and relapse rates and shows that MPA patients with signs of ground-glass opacities or pleural effusions are more prone to develop relapses, what may be of interest when deciding about closer monitoring and possibly intensified therapy.

Further investigations require of course far larger cohorts, precise group matching and the inclusion of relevant confounding factors, such as the glucocorticoid dose used.

Fazit
Diese Studie wirft einen Blick auf spezifische CT-Muster im Zusammenhang mit klinischen Ergebnissen und Rückfallraten von ANCA-assoziierten Vasculitiden und zeigt, dass MPA-Patienten mit Anzeichen von ground-glass-Muster oder Pleuraergüssen eher zu Rückfällen neigen, was bei der Entscheidung über eine engmaschigere Überwachung und möglicherweise intensivierte Therapie von Interesse sein kann.

References:
[1] Vogt K, CB Fink et al. Distinct pulmonary patterns in ANCA-associated vasculitides: insights from a retrospective single center cohort study. Rheumatology International. doi.org/10.1007/s00296-024-05664-8. published online 13 August 2024

Composed by Dr. med. Ralph Melzer, Chefarzt Rheumatologie, Luzerner Kantonsspital