Abstract
The risk of bleeding and rebleeding from cerebral arteriovenous malformation (AVM) was analysed in 142 cases. Life table analysis was used for the assessment, and surgical cases in preoperative period were also included for the analysis, in addition to non-surgical cases. The follow-up period ranged from one month to 29 years with a mean of 4 years.
The age of the patients at onset ranged from 6 to 69 years, and averaged 29 years. Seventy percent of the patients were males. As an initial symptom, intracranial bleeding was noted in 105 cases and other symptoms in 37 cases. The rate of bleeding as an initial symptom was significantly higher in patients with a small AVM (within 5cm3) than larger ones (p<0.01).
During the follow-up period, 26 patients had rebleeding and 6 patients with initially unruptured AVM had bleeding. Mortality in cases with single bleeding was 3%, double 14%, and triple 28%.
Cumulative probability of bleeding for all patients after the onset was 9%in the first year, and 22%in the fifth year. The probability of rebleeding was 13%in the first year and 30%in the fifth year, while the risk of bleeding with an initially unruptured AVM was 3%in the first year and 7%in the fifth year. There was no correlation between the cumulative probability of rebleeding in five years and age at the onset or location or volume of AVM.
