Comparison of conservative management, microsurgery only, and microsurgery with preoperative embolization for unruptured arteriovenous malformations: A propensity score weighted prospective cohort study.

[AIMS] To compare the efficacy and deficiency of conservative management (CM), microsurgery (MS) only, and microsurgery with preoperative embolization (E + MS) for unruptured arteriovenous malformations (AVMs).

[METHODS] We prospectively included unruptured AVMs undergoing CM, MS, and E + MS from our institution between August 2011 and August 2021. The primary outcomes were long-term neurofunctional outcomes and hemorrhagic stroke and death. In addition to the comparisons among CM, MS, and E + MS, E + MS was divided into single-staged hybrid and multi-staged E + MS for further analysis. Stabilized inverse probability of treatment weighting using propensity scores was applied to control for confounders by treatment indication across the three groups.

[RESULTS] Of 3758 consecutive AVMs admitted, 718 patients were included finally (266 CM, 364 MS, and 88 E + MS). The median follow-up duration was 5.4 years. Compared with CM, interventions (MS and E + MS) were associated with neurological deterioration. MS could lower the risk of hemorrhagic stroke and death. Multi-staged E + MS was associated with neurological deterioration and higher hemorrhagic risks compared with MS, but the hybrid E + MS operation significantly reduced the hemorrhage risk.

[CONCLUSION] In this study, unruptured AVMs receiving CM would expect better neurofunctional outcomes but bear higher risks of hemorrhage than MS or E + MS. The single-staged hybrid E + MS might be promising in reducing inter-procedural and subsequent hemorrhage.