Long-Term Outcomes and Natural Course of Giant Cerebral Arteriovenous Malformations (> 6 cm): Insights From a National Multicenter Propensity Score-Matched Cohort.

OBJECTIVES

This study evaluated the natural history of giant cerebral arteriovenous malformations (AVMs) over 6 cm and compared long-term outcomes of interventional treatment versus conservative management.

MATERIALS AND

METHODS

Patients with AVMs > 6 cm were identified from a national multicenter prospective registry (MATCH). Rupture risk factors were analyzed with uni- and multivariate models. Propensity score matching balanced intervention and conservative groups. The primary outcome was long-term hemorrhagic stroke or death; secondary outcomes included obliteration rates and neurological status. Subgroup and sensitivity analyses assessed robustness.

RESULTS

From August 2011 to December 2021, 380 patients with giant AVMs were enrolled. Annual rupture risk was 2.4% for unruptured lesions, 9.4% for previously ruptured, and 3.6% overall. Ventricular involvement (OR = 3.61) and draining vein stenosis (OR = 2.61) were independent hemorrhage risk factors. Over a mean follow-up of 7.3 years, intervention did not significantly reduce hemorrhagic stroke or death compared to conservative management but was associated with higher hemorrhagic stroke risk (HR = 2.04) and neurological deterioration, despite higher obliteration rates (39.1%). Stratified analysis suggested microsurgery and embolization alone were less favorable, while embolization plus radiosurgery more effectively reduced hemorrhagic stroke or death. Subgroup analysis indicated conservative management was preferable for higher S-M grades, unruptured AVMs, and eloquent brain regions.

CONCLUSION

The annual rupture rate of giant AVMs (> 6 cm) is approximately 3.6%. Interventional treatment for giant AVMs is not superior to conservative management, and the risks of hemorrhagic stroke and neurological deterioration remain substantial-particularly for unruptured, high-grade, or eloquently located AVMs.