Small Ruptured Anterior Communicating Artery Aneurysms in the Endovascular Right-of-First-Refusal Era: Intraprocedural Rupture Risk and Retreatment at Follow-up

Ruptured small anterior communicating artery (ACoA) aneurysms can pose a technical challenge for endovascular therapy. We sought to explore treatment and follow-up results in the modern endovascular right of first refusal era. Smaller (≤ 7mm) ruptured aneurysms of the ACoA undergoing treatment were compared with non-ACoA counterparts, and further dichotomized by size (≤3mm and 3-7mm). Immediate- and 2-year angiographic results, procedural complications, retreatment, and functional results at follow-up were stratified by treatment modalities and compared between aneurysm location and size groups. Of 449 consecutive small ruptured aneurysms, 35% (n=155) were ACoA. Endovascular treatment was the first-line option in 68%. While the immediate aneurysm occlusion was more favorable in the ACoA group compared to other aneurysms treated endovascularly (Raymond-Roy I-II, 89% vs. 74%, P= .003), the residual and/or recanalization requiring retreatment rate at 2 years was higher (27% vs. 17%, P= .04). ACoA aneurysms were associated with a 2-fold higher risk of retreatment (OR 2.08, P= .02) in multivariate analyses of the endovascular cohort. The incidence of intraprocedural rupture was numerically higher for coiled ≤3mm ACoA aneurysms (12.5% vs. 2.2%, P= .11), corresponding to a higher major complication rate (12.5% vs. 1.1%, P= .06) in this subgroup. Endovascularly treated ≤3mm ACoA aneurysms were associated with a 4-fold higher risk of recanalization (OR 4.4, P= .01) and retreatment (OR 3.8, P= .03). While the immediate efficacy is satisfactory for endovascularly-treated small ruptured ACoA aneurysms, there are increasing needs for retreatment and non-negligible risks for coiling ACoA aneurysms ≤3mm.