Background It is well known that hemodynamic stress may impact the recanalization of coiled aneurysms. One of the most common sites for aneurysms to develop is the posterior communicating artery (PcoA), the variants of which are defined by diameter ratios (PcoA/P1 segment).

Objective This study was undertaken to investigate the impact of a fetal-type posterior cerebral artery (PCA) on recanalization of PcoA aneurysms after coil embolization based on matched-pair (fetal vs non-fetal PCA) analysis.

Methods A total of 480 consecutive PcoA aneurysms (PCA: fetal, n=156; non-fetal, n=324) subjected to coil embolization between January 2007 and June 2017 were selected for study. All lesions were followed for ≥6 months via radiologic imaging, grouped by adjacent PCAs as fetal (PcoA/P1 >1) or non-fetal (PcoA/P1 ≤1) type. Paired subjects were matched (1:1) for several relevant variables.

Results Of the 480 coiled aneurysms, 159 (33.1%) showed recanalization (minor, 76; major, 83) in the course of follow-up (mean 33.8±21.9 months), developing significantly more often in fetal (37.8%) than in non-fetal (26.9%; p=0.020) PCA types. Once matched, however, 6-month and cumulative recanalization rates did not differ significantly by group (p=0.531 and p=0.568, respectively). Complications (hemorrhage, p=0.97; thromboembolism, p=0.94) during endovascular coil embolization also showed similar rates in these groups.

Conclusions The chances of recanalization after coil embolization seem to be greater in PcoA aneurysms than in intracranial aneurysms overall, thus calling for careful follow-up monitoring. Surprisingly, PcoA type appeared unrelated in this regard.