Intracranial Arteriovenous Malformation RUpture riSk Study (ICARUSS): A Multicentric Case-Control Study

Introduction: Intracranial arteriovenous malformations (AVMs) cause intracranial hemorrhage, and the factors that have been associated with a high rupture risk are prior hemorrhage, a small nidus, a deep location of the nidus, a single draining vein, deep venous drainage, aneurysms associated with AVMs, or draining vein stenosis. The role of draining vein diameters in rupture risk is unknown. The aim of the present study was to investigate the predictors for intracranial AVM rupture and to examine the role of draining vein diameters as a surrogate measure of flow-shear stress in the nidus in predicting the risk of AVM rupture. Materials and Methods: Two hundred three patients were included in this multicenter case-control study, of which 117 (57%) had unruptured AVMs, and 86 (43%) had ruptured AVMs. Clinical and angiographic data were registered by 5 independent investigators who were blinded regarding the endpoints of the study. Results: In the univariate analysis, the variables associated with AVM rupture were age, a deep nidus, the nidus diameter, a deep draining vein, a single draining vein, deep and single draining veins, the draining vein diameter, and a draining vein diameter > 5 mm. The variables significantly associated with AVM hemorrhage risk after adjusted (multivariate) analysis were age (OR 0.97, 95% CI 0.95-0.99, p=0.015), a deep nidus (OR 3.21, 95% CI 1.11-9.22, p=0.030), nidus diameter (OR 0.94, 95% CI 0.91-0.96, p 5 mm (OR 5.80, 95% CI 2.70-12.47, p 5 mm was positively associated with the risk of AVM rupture. A prospective study is necessary to confirm these findings. Funding Statement: This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors. Declaration of Interests: The authors state: "There are no competing interests to declare." Ethics Approval Statement: This was a multicentric, observational, case-control study. The study protocol was approved by the institutional review board, which waived the need for written informed consent from participants. The article was prepared accordingly, with recommendations from the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines.