“…Ondra et al 7 published the results of almost 24 years of follow-up in a cohort of bAVM patients in Finland, and established an annual risk of bAVM hemorrhage of 4% per year, regardless of bAVM characteristics and clinical presentation. Graf, 5 Crawford, 3 and Fults 4 showed that bAVMs may have different behavior during follow-up, with an increased risk of bleeding in the first year after diagnosis. In a more recent series, Mast et al 23 demonstrated that the risk of hemorrhage in follow-up can be widely variable, from 2.2% to 17.8% per year, depending on presentation, AVM venous drainage, and sex.…”