How commonly do aneurysms leak or rupture?
Aneurysms leak or rupture at the rate of 1-2% per year. That is, if you identify 100 individuals with brain aneurysms and follow them over a year, 1 or 2 of them will suffer a leak. This effect is cumulative. That is, if someone has a known brain aneurysm, and they wait say 10 years, they will have exposed themselves to a 10-20 percent chance of suffering a leak. This fact is very useful in helping patients decide whether or not to have their aneurysms repaired.
