Comparing Apples to Apples: Propensity Score-Matched Analysis and Comparison of Endovascular and Microsurgical Treatment of Unruptured Middle Cerebral Artery Aneurysms

Introduction: Aneurysm location heavily influences the choice between microsurgical or endovascular treatment of unruptured intracranial aneurysms (UIAs). Middle cerebral artery (MCA) aneurysms traditionally have leaned towards microsurgery due to their complex anatomy, precluding straightforward endovascular treatment. However, there is a growing trend towards endovascular treatment for MCA UIAs. This single-center study aims to compare matched MCA UIAs treated.

Methods: We employed propensity score matching (PSM) using a generalized linear model based on distance, employing the nearest-neighbor matching method and a 1:1 ratio. The PSM was adjusted for age, aneurysm dome dimension, and PHASES score. We used ordinal and binary logistic regression models, adjusting for response variable weights, to analyze the relationship between treatment and covariates.

Results: A total of 167 patients with 191 MCA UIAs were included in the study, with a median follow-up of 86 months. Of these, 156 aneurysms were treated microsurgically, and 35 (18%) endovascularly.
After matching, 35 patients that underwent clipping (26 females, median age 58.66 ± 13.1 years) were compared to 35 patients who underwent endovascular treatment (27 females, median age 58.23 ± 10.4 years). Patients treated endovascularly more often had multiple aneurysms (p = 0.03). In the long-term follow-up, no significant differences were observed in modified Rankin Scale (mRS) outcomes (p = 1), hemorrhage (8.6% in the endovascular group, 0 in microsurgical, p = 0.08), or change in neurological status after treatment (evaluated quantitatively and qualitatively as mRS difference, p = 0.61).

Conclusion : In the long-term follow-up, there were no significant differences in outcomes found between microsurgical and endovascular treatment of MCA UIAs in matched groups. Notably, there were three hemorrhages in the endovascular group (including one from the previously treated MCA UIA), but this difference was statistically insignificant.