The risk of AVM bleeding is 2 to 3% per year. Death from the first hemorrhage is between 10 to 30%. Once a hemorrhage has occurred, the AVM is 9 times more likely to bleed again during the first year. Patients often want to know their lifetime risk of bleeding if they're weighing the risks and benefits of having surgery. Using the following formula one can calculate their risk (1):
Lifetime risk (%) = 105 - patient's age
For example, a 25-year-old man has an 80% lifetime risk of bleeding (at least once). Many factors affect this percentage, including where the AVM is located and what type of AVM it is. It's best to talk to your doctor about your own individual risk.