Comparison of patients with biopsy positive and negative primary angiitis of the central nervous system.

Objective: There is limited evidence on when to obtain a central nervous system (CNS) biopsy in suspected primary angiitis of the central nervous system (PACNS). Our objective was to identify which clinical and radiological characteristics were associated with a positive biopsy in PACNS.

Methods: From the multicentre retrospective Cohort of Patients with Primary Vasculitis of the CNS (COVAC), we included adults with PACNS based on a positive CNS biopsy or otherwise unexplained intracranial stenoses with additional findings supportive of vasculitis. Baseline findings were compared between patients with a positive and negative biopsy using logistic regression models.

Results: Two hundred patients with PACNS were included, among which a biopsy was obtained in 100 (50%) and was positive in 61 (31%). Patients with a positive biopsy were more frequently female (odds ratio [OR] 2.90; 95% CI: 1.25, 7.10; P = 0.01) and more often presented with seizures (OR 8.31; 95% CI: 2.77, 33.04; P < 0.001) or cognitive impairment (OR 2.58; 95% CI: 1.11, 6.10; P = 0.03). On imaging, biopsy positive patients more often had non-ischaemic parenchymal or leptomeningeal gadolinium enhancement (OR 52.80; 95% CI: 15.72, 233.06; P < 0.001) or ≥1 cerebral microbleed (OR 8.08; 95% CI: 3.03, 25.13; P < 0.001), and less often had ≥1 acute brain infarct (OR 0.02; 95% CI: 0.004, 0.08; P < 0.001). In the multivariable model, non-ischaemic parenchymal or leptomeningeal gadolinium enhancement (adjusted OR 8.27; 95% CI: 1.78, 38.46; P < 0.01) and absence of ≥1 acute brain infarct (adjusted OR 0.13; 95% CI: 0.03, 0.65; P = 0.01) were significantly associated with a positive biopsy.

Conclusion: Baseline clinical and radiological characteristics differed between biopsy positive and negative PACNS. These results may help physicians individualize the decision to obtain a CNS biopsy in suspected PACNS.