Background Recanalization rates after coil embolization are known to be higher in cerebral aneurysms of the posterior (vs anterior) circulation. Although often grouped with anterior lesions, aneurysms of the posterior communicating artery (PcoA) may nevertheless behave differently.

Objective We performed a comparative analysis to explore differences in recanalization rates of PcoA and anterior communicating artery (AcoA) aneurysms, both integral to the circle of Willis.

Methods Between October 2012 and July 2017, 699 AcoA (n=427) and PcoA (n=272) aneurysms were treated by endovascular coil embolization, monitoring 667 (95.4%) via radiologic imaging for ≥ 6 months. Cumulative recordings of medical and imaging data were retrospectively reviewed, conducting propensity score matching and binary logistic regression analysis.

Results In the 667 aneurysms followed longer term, recanalization occurred in 111 (16.6%; minor 72; major 39) and was significantly more frequent in PcoA (25.5%) than in AcoA (11.0%; P<0.01) aneurysms during similar follow-up periods. After 1:1 propensity score matching, an even greater proclivity for recanalization was evident at PcoA sites (PcoA 23.0%; AcoA 12.2%; P<0.01). Although A1 segment dominance was linked to recanalization in AcoA aneurysms (18.2% vs 7.6%; P=0.01), the PcoA counterpart had no bearing on recanalization (27.7% vs 24.1%; P=0.51).

Conclusions Despite a clear preponderance of AcoA aneurysms, recanalization of PcoA aneurysms proved significantly greater, attesting to posterior circulation behavior.