Outcomes of arteriovenous malformations with single versus multiple draining veins: A multicenter study

Background: Cerebral arteriovenous malformations (AVMs) are complex vascular lesions that pose a risk for hemorrhagic stroke. The number of draining veins has recently emerged as a significant predictor of rupture risk. This multicenter study aimed to evaluate the outcomes in adult AVM patients with single versus multiple draining veins. Methods: We conducted a retrospective analysis of 735 AVM patients from the Multicenter International Study for Treatment of Brain AVMs (MISTA) database. Patients were categorized into single draining vein (n = 430) and multiple draining veins (n = 305) groups. Logistic and linear regression models were used to assess outcomes, adjusting for baseline characteristics, including age, rupture status, Spetzler-Martin grade, and other relevant factors. Results: After adjustment, no significant differences were observed in complete AVM obliteration at last follow-up between the multiple and single draining veins groups (OR: 1.1; 95 % CI: 0.72–1.93, p = 0.49) after any treatment type. Good functional outcomes at last follow-up (mRS 0–2) were similar between the two groups (OR: 1.00; 95 % CI: 0.48–2.09, p = 0.98), as were retreatment rates (OR: 1.68; 95 % CI: 0.74–3.83, p = 0.21). Ruptured AVMs were more common in the single draining vein group (52.0 % vs. 35.4 %, p < 0.001). Patients in the multiple draining vein group had lower odds of hemorrhagic complications compared to the single vein group (OR: 0.38; 95 % CI: 0.14–1.02, p = 0.05). Conclusion: Single draining vein AVMs were more likely to present with rupture, but no significant differences in obliteration rates, functional outcomes, or retreatment rates were found between the groups after adjustment. These findings suggest that while venous drainage patterns may influence initial presentation, they do not appear to affect overall treatment success or patient prognosis after any treatment type. Further studies are needed to confirm.