MO279DETERMINANTS TO CONSIDER THERAPEUTIC PLASMA EXCHANGE FOR TREATMENT OF SEVERE ANCA-ASSOCIATED VASCULITIS: A RETROSPECTIVE STUDY FROM A SINGLE CENTER
Authors: Tampe Björn , Hakroush Samy 
Published: May 2021

Abstract

Background and Aims
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic vasculitis, most frequently presenting as microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA). Pathogenic ANCAs trigger a deleterious immune response resulting in pauci-immune necrotizing and crescentic glomerulonephritis (GN). Standard therapeutical regimens include aggressive immunosuppressive therapy. Since some patients require RRT despite intensive immunosuppressive therapy, additional therapeutic plasma exchange (PEX) to deplete pathogenic ANCAs has been recommended but its value has recently been questioned. Because therapeutic decision making is crucial in these critically ill patients, we here aimed to identify determinants for PEX consideration in a retrospective study from a single center tertiary hospital in a real-world population of 46 patients with severe AAV requiring intensive care treatment.

Method
A total number of 46 patients with biopsy-proven AAV at the University Medical Center Göttingen were retrospectively included between 2015 till 2020. While no formal approval was required for the use of routine clinical data, a favorable ethical opinion was granted by the local Ethics committee. Medical records were used to obtain data on age, sex, diagnosis (MPO or PR3) and laboratory results (serum creatinine, C-reactive protein/CRP, urinary albumin/creatinine ration). The estimated glomerular filtration rate (GFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. A renal pathologist (SH) evaluated all biopsies. Within a renal biopsy specimen, each glomerulus was scored separately for the presence of necrosis, crescents and global sclerosis. Consequently, the percentage of glomeruli with any of these features was calculated as a fraction of the total number of glomeruli in each renal biopsy. Apart from these categories, the degree of interstitial fibrosis/tubular atrophy (IF/TA) was quantified. Based on these scorings, histopathological subgrouping according to Berden et al (focal, crescentic, mixed or sclerotic class) and ARRS according to Brix et al (low, medium or high risk) were performed.

Results
The decision to consider PEX was more likely in patients with need for intensive care treatment and severe renal dysfunction. In contrast, short-term outcomes did not depend on clinical or laboratory characteristics assessed at admission. Histopathological analysis confirmed active disease reflected by increased glomerular necrosis and crescents, but these histopathological findings did not associate with short-term outcome either. Interestingly, only increased global glomerular sclerosis in renal biopsies associated with a detrimental short-term outcome.

Conclusion
In conclusion, our study investigated determinants for the consideration of therapeutic PEX in patients with severe AAV requiring intensive care treatment. This aspect underscores the need for renal biopsy and requires further investigation in a prospective controlled setting for therapeutic decision making especially in patients with severe AAV requiring intensive care treatment, especially important for treating intensivists.