Venous aneurysms in unruptured supratentorial brain arteriovenous malformations: a protective factor against hemorrhagic stroke and insights into hemodynamic mechanisms

This study endeavors to clarify the impact of venous aneurysms (VA) on hemorrhagic risk in brain arteriovenous malformations (AVMs) and uncover potential hemodynamic mechanisms, utilizing quantitative digital subtraction angiography (QDSA) technology and survival dataset. Patients were enrolled in a multicenter prospective collaboration registry between August 2011 and August 2021, and subsequently categorized into the VA and non-VA cohorts. Using propensity score-matched survival analysis, we quantitatively assessed the natural risk of hemorrhagic stroke in these two cohorts. Additionally, a quantitative hemodynamic analysis was conducted to explore the distinctions in hemodynamic characteristics between these two cohorts. Among 3758 consecutive AVMs documented at a single center from the registry, 820 unruptured AVMs who maintained conservation management over 1 month were identified. Following a two-step matching process, 504 cases were retained for survival analysis and 408 cases for hemodynamic analysis. Overall, the presence of VA emerged as a protective factor, associated with a decreased risk of hemorrhagic stroke (HR, 0.21 [95% CI: 0.07-0.62], p = 0.004). Distinct hemodynamic characteristics were observed in AVMs with VA, showing a lower stasis index in two components of AVMs-the nidus (p = 0.014) and the main draining vein (p = 0.018). In this observational prospective cohort study, the presence of VA is associated with a decreased risk of hemorrhagic stroke in AVMs, suggesting an underlying hemodynamic mechanism involving the redistribution of excessive pressure loads within the AVM nidus by the VA. Questions What impact, if any, does VA have on the hemorrhagic risk in brain AVMs? Findings Presence of VA is associated with a decreased hemorrhagic stroke risk through the redistribution of pressure loads. Critical relevance VA in brain AVMs emerges as a protective factor against hemorrhagic stroke. Understanding this association and the underlying hemodynamic mechanisms offers valuable guidance for preventive strategies and informs clinical decision-making, improving overall patient care.