The natural history of unruptured intracranial arteriovenous malformations

TLDR

The authors performed a long‑term retrospective cohort study of 168 patients with clinically unruptured intracranial AVMs, reviewing Mayo Clinic records from 1974–1985 and following 166 patients for a mean of 8.2 years with imaging to assess natural history. Intracranial hemorrhage occurred in 18 % of patients, with a mean annual risk of 2.2 % that rose over time; 29 % of ruptures led to death and 23 % of survivors had significant long‑term morbidity, while AVM size and hypertension did not predict rupture.

Abstract

✓ The authors conducted a long-term follow-up study of 168 patients to define the natural history of clinically unruptured intracranial arteriovenous malformations (AVM's). Charts of patients seen at the Mayo Clinic between 1974 and 1985 were reviewed. Follow-up information was obtained on 166 patients until death, surgery, or other intervention, or for at least 4 years after diagnosis (mean follow-up time 8.2 years). All available cerebral arteriograms and computerized tomography scans of the head were reviewed. Intracranial hemorrhage occurred in 31 patients (18%), due to AVM rupture in 29 and secondary to AVM or aneurysm rupture in two. The mean risk of hemorrhage was 2.2% per year, and the observed annual rates of hemorrhage increased over time. The risk of death from rupture was 29%, and 23% of survivors had significant long-term morbidity. The size of the AVM and the presence of treated or untreated hypertension were of no value in predicting rupture.