The Minimum Distance May Affect Perioperative Complications and Completed Occlusions of Endovascular Treatment for Tandem Intracranial Aneurysms: A Multi-Institutional Retrospective Study

Abstract

Background: Tandem aneurysms (TAs) are a distinct type of multiple intracranial aneurysms (IAs), the treatment strategies for which remain controversial. We aimed to reveal the clinical and angiographic outcomes of endovascular treatment as well as their risk factors in these complex multiple IAs. Methods: This multicenter, retrospective follow-up study was carried out in 3 hospitals in China. In total, clinical and angiographical data of 137 patients with 145 lesions (7 patients had bilateral lesions) and 315 TAs were collected. The treatment strategies were divided into full or partial treatment, single- or multiple-session treatment, and coiling (including single coiling and stent-assisted coiling)- or flow-diverting stent (FDS) treatment. Perioperative complications, as well as angiographic and clinical outcomes and their risk factors, were analyzed using univariate analysis and a multiple regression model. Results: Of treated TA lesions, 17 (16.0%) perioperative complications were found. Significant differences were found between the single- and multiple-session treatment groups (p = 0.012). At the latest follow-up, there were no significant differences in the modified Raymond Scale scores between different treatment groups. Significant differences were found in the embolization degree between the coiling and FDS groups (p = 0.038) and between the single common stent (without coiling) and the other treatment groups (p < 0.001). In IAs managed by a single LVIS stent (without coiling), 60% achieved improved or completed occlusion. Multivariate regression analysis found that a shorter minimum distance (odds ratio [OR] 5.967, 95% confidence interval [CI] 1.366–26.074; p = 0.018), multiple-session treatment (OR 9.961, 95% CI 1.707–58.127; p = 0.011), and diabetes (OR 8.106, 95% CI 1.928–34.084; p = 0.004) were predictors of perioperative complications, while shorter minimum distance (OR 5.619, 95% CI 1.493–21.152; p = 0.011), greater diameter ratio (OR 3.621, 95% CI 1.014–12.937; p = 0.048), and greater size ratio (OR 2.424, 95% CI 1.007–5.834; p = 0.048) were predictors of low completed occlusion rate. Conclusions: Both coiling and FDS can be utilized safely and can achieve similar clinical outcomes. FDS and LVIS are recommended for IAs that do not require embolization but cannot be prevented from being covered by stents. A multiple-session treatment may increase the treatment risk, and the minimum distance may affect the incidence of perioperative complications and completed occlusions. Further hemodynamic and prospective studies on such TAs in close proximity to one another are needed.