Posterior Communicating Artery-incorporated Internal Carotid-Posterior Communicating Artery Aneurysms Prone to Recur After Coil Embolization

OBJECTIVE: The objective was to clarify predisposing factors of recurrence after coil embolization for internal carotid-posterior communicating artery (IC-Pcom) aneurysms. METHODS: The medical records were retrospectively reviewed and patients harboring IC-Pcom aneurysms treated with coil embolization between June 2004 and June 2020 were identified. Aneurysms whose 3-dimensional images were available, whose initial treatment was performed during the study period, and whose follow-up term was more than 1 year were included. Information of the patients, the aneurysms and Pcoms, the initial treatment, and angiographic outcomes were collected. The IC-Pcom aneurysms were divided into Pcom-incorporated when their neck mainly rode on the Pcom or non-Pcom-incorporated when their neck mainly rode on the internal carotid artery or the classification was equivocal. Relationship between these factors and recurrence was analyzed. RESULTS: Fifty-seven IC-Pcom aneurysms from 55 patients were recruited. Fifteen of the 57 aneurysms were categorized into Pcom-incorporated. Eighteen of the 57 aneurysms recurred. Mean follow-up term was 74.3 months and mean duration between the initial treatment and recurrence was 47.9 months. On univariate analyses, ruptured (P = 0.004), fetal-type Pcom (P = 0.002), and Pcom-incorporated (P < 0.001) were significantly correlated with recurrence. Multivariate analysis demonstrated that Pcom-incorporated aneurysms were significantly associated with recurrence (P < 0.001) along with ruptured (P = 0.027). Kaplan-Meier estimate demonstrated that cumulative recurrence-free rate was significantly lower in Pcom-incorporated aneurysms compared with non-Pcom-incorporated aneurysms (log-rank P < 0.001). CONCLUSIONS: Pcom-incorporated IC-Pcom aneurysms were susceptible to recur after coil embolization, especially when ruptured and the incorporated Pcom was fetal-type.