Selective compromise of hypoplastic posterior communicating artery variants with aneurysms treatable by coil embolization: clinical and radiologic outcomes

Impact of fetal-type posterior cerebral artery on recanalization of posterior communicating artery aneurysms after coil embolization: matched-pair case-control study

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.

Comparative analysis of coil embolization in posterior and anterior communicating artery aneurysms

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.