Reconstructive Endovascular Treatment of Intracranial Ruptured Posterior Circulation Aneurysms Located on Small Arteries: Complications and Long-Term Results

Objective: Assess the complications, clinical outcomes, and angiographic results of endovascular treatment (EVT) for ruptured intracranial posterior circulation aneurysms in small arteries, and identify their risk factors. Methods: We conducted a retrospective analysis of 79 patients with ruptured posterior circulation aneurysms in small arteries (the diameter of the parent artery was <= 2 mm) treated at our hospital between January 2014 and August 2023. All patients received EVT. The study examined risk factors associated with in-hospital complications and clinical outcomes. Results: The incidence of in-hospital complications among all patients receiving reconstructive EVT was 30.4% (24/79). The median clinical follow-up time of the patients was 45 months (interquartile range: 28-65 months). Favorable clinical outcomes were observed in 83.5% (66/79) of patients, while the overall mortality rate was 11.4% (9/79). Of the 75 survivors, 59 (78.7%) underwent angiographic follow-up, revealing a median follow-up time of 11 months (interquartile range: 6-12 months) and a complete occlusion rate of 84.7% (50/59). Residual aneurysms occurred in 6.8% (4/59) of patients. Survival analysis indicated 1- and 3-year complication-free survival rates of 70.9% and 65.5%, respectively, and overall 1- and 3-year survival rates of 89.6% and 87.6%. Multivariate analysis identified external ventricular drainage (P = 0.007) as an independent risk factor for in-hospital complications. Older age (P = 0.024) and a World Federation of Neurosurgical Societies grade of 4-5 (P < 0.001) were independent risk factors for unfavorable clinical outcomes. Conclusions: Reconstructive EVT for ruptured intracranial posterior circulation small artery aneurysms was generally safe and effective. However, the risk of complications and unfavorable clinical outcomes persisted. External ventricular drainage was a significant risk factor for in-hospital complications, whereas older age and higher World Federation of Neurosurgical Societies grades were predictors of unfavorable clinical outcomes.