On apples, oranges, and ARUBA

Excerpt

Arteriovenous malformations (AVMs) are congenital vascular lesions that are associated with long-term excess mortality and morbidity essentially related to haemorrhagic stroke [10]. The prevalence of brain AVMS (BAVMs) is believed to be between 15 and 18 per 100,000 adults [1], and the incidence is estimated at 1 per 100,000 per year [19]. Roughly half of the patients with BAVMs present with intracerebral haemorrhage (ICH), resulting in a first-ever hemorrhage rate of 0.55 per 100,000 person-years [19]. The annual risk of haemorrhage is estimated at 1–4 % [12], but it may be as low as 0.9 % in patients with unruptured, superficially located brain AVMs with superficial drainage and may be as high as 34 % in patients with ruptured, deeply seated brain AVMs with deep venous drainage [20]. The known risk factors for bleeding include AVM size, deep venous drainage, deep location, and associated aneurysm [4, 9, 20, 21]. BAVMs are commonly classified according to the five-tier Spetzler-Martin scale, which is a composite score of nidus size, eloquence of adjacent brain and presence of deep venous drainage [17], although, recently, a simplified three-tier classification has been proposed [18]. …