Abstract
OBJECTIVE: Stent-free coil embolization has advantages such as a low periprocedural risk and elimination of the need for antiplatelet therapy. Recent advancements in coil technology and adjunctive techniques, including the double-catheter method, may have contributed to improved outcomes. This study aimed to evaluate the safety, efficacy, and limitations of stent-free coil embolization for internal carotid-posterior communicating artery (IC-Pcom) aneurysms in current endovascular practice. METHODS: Between January 2017 and March 2024, 65 unruptured IC-Pcom aneurysms were initially treated with coil embolization at our institution. Of these, 58 cases without neck-bridging stents were analyzed. Final embolization status was assessed by follow-up MRA and classified according to the Raymond classification. RESULTS: The double-catheter coil embolization (DCC) was performed in 42 cases (72%). The mean follow-up duration was 42 months. Retreatment was required in 3 patients (5.2%), and 4 patients ultimately had residual aneurysms. Residual aneurysm was significantly associated with aneurysm size (dome, p = 0.033; height, p = 0.014; neck, p = 0.004) and postoperative embolization status (p = 0.002). Cutoff values predictive of residual aneurysm were: neck, 4.83 mm (area under the curve [AUC], 0.94; sensitivity, 1.0; specificity, 0.87); height, 5.35 mm (AUC, 0.88); and dome, 7.29 mm (AUC, 0.82). Complete obliteration was significantly associated with younger age (p = 0.042), absence of PcomA incorporation (p = 0.017), smaller PcomA diameter (p = 0.037), smaller aneurysm dimensions, and favorable embolization status (p <0.001). In multivariate analysis, a neck diameter <4.25 mm emerged as the sole independent predictor of complete obliteration (odds ratio, 6.33; 95% confidence interval, 1.27-31.4; p = 0.024). CONCLUSION: Stent-free coil embolization achieved high rates of complete occlusion in aneurysms with a neck diameter <4.25 mm. However, despite the adoption of modern coils and advanced techniques such as the double-catheter method, larger aneurysms exceeding this cutoff may recur during midterm follow-up, underscoring the need for alternative treatment strategies.