Arterial afferent count is associated with arteriovenous malformation grade but not with rupture risk in a South American cohort

Cerebral arteriovenous malformations (AVMs) are complex vascular lesions that carry a significant risk of intracranial hemorrhage. While morphological features such as nidus size and venous drainage patterns have been associated with rupture, the predictive value of the number of arterial afferents remains unclear. To evaluate the association between the number of arterial afferents and AVM rupture, and to identify independent morphological predictors of hemorrhage in a cohort of Ecuadorian patients. We conducted a cross-sectional, observational study of 129 patients diagnosed with cerebral AVMs at a national neurosurgical referral center between 2020 and 2024. Angiographic characteristics—including nidus size, arterial afferents, venous drainage, and intranidal aneurysms—were assessed using digital subtraction angiography. Clinical presentation and rupture status were recorded. Univariate and multivariate logistic regression models were used to identify predictors of AVM rupture. AVMs with ≥ 5 arterial afferents were associated with larger nidus size and higher Spetzler-Martin grades but did not show an independent association with rupture (OR = 1.34, p = 0.22). Ruptured AVMs were significantly smaller in diameter and more likely to harbor intranidal aneurysms (OR = 2.48, p = 0.01). Seizures were more frequent in non-ruptured AVMs, while altered consciousness and neurological deficits predominated in ruptured cases. The number of arterial afferents reflects AVM complexity but is not an independent predictor of rupture. Nidus size and intranidal aneurysms are key morphological risk factors for hemorrhage. Future risk models should integrate venous hemodynamics and advanced imaging to improve rupture prediction.