Are brain arteriovenous malformations congenital or developmental? Evidence from paediatric age data.

Abstract

The natural history of pediatric brain arteriovenous malformations (AVMs) remains uncertain, particularly regarding their origin (congenital versus postnatal) and risk of rupture. This study analyzes age-related patterns in AVM presentation from a single quaternary referral center. A retrospective review of 275 pediatric AVM cases from 2009-2022, was conducted using radiological, surgical, and hospital records to identify age at first hemorrhage and associated AVM characteristics. Two mathematical models were developed: (i) a congenital model with a variable age-dependent rupture risk, and (ii) a postnatal model of AVM development, assuming age-dependent variable incidence and a constant rupture rate. Data were normalized to institutional age-based presentation rates. Hemorrhagic presentation peaked between ages 7 and 14, before declining sharply, a trend which remained after normalization. A congenital model with age-dependent rupture rate accounted well for the empirical distribution, while the postnatal model overpredicted adolescent hemorrhage and could not account for the observed decline. However, the rising distribution of asymptomatic AVMs with age suggests that a purely congenital model is implausible. The study supports a model where pediatric brain AVMs are largely postnatally acquired, though likely very early, with age-dependent varying annual risk of rupture peaking at age 13, before declining to an adult risk rate.