The impact of selection bias in the treatment for ruptured anterior communicating artery aneurysms: different results or different patients?

BACKGROUND

Anterior communicating artery is one of the most frequent locations for the development of intracranial aneurysm. The availability and advances of different treatments modalities allows for case-specific selection, but potentially impacts our ability to assess equipoise among them.

OBJECTIVE

Investigate and compare clinical and morphological variables among surgical and endovascular treatment groups with ruptured anterior communicating artery aneurysms.

METHODS

Data from patients from a single university hospital treated for ruptured anterior communicating aneurysms after multidisciplinary discussion in a period from January 2009 to January 2020 were retrospectively reviewed. Demographics, clinical status, aneurysm morphologic features and in-hospital complications were registered for each treatment (endovascular coiling vs. microsurgical clipping). Clinical assessment was made from outpatient evaluation at 1-year follow-up.

RESULTS

A total of 119 patients was obtained adding surgical ( = 80) and endovascular ( = 39) treatment groups. No significant changes between groups were detected regarding gender, age of treatment or other risk factors. Global complication rate ( = 0.335,  = 0.225,  = 0.428) and clinical outcome ( = 0.802) was similar among both groups. Univariate and multivariate analysis revealed statistically significant differences between endovascular and surgical treatment groups regarding dome orientation ( = 0.011), aneurysm height ( < 0.001) and maximum diameter ( < 0.001), aspect-ratio ( < 0.001), dome-to-neck ratio ( < 0.001) and dome diameter ( = 0.014).

CONCLUSIONS

Despite similar clinical outcomes and rate of complications, morphological differences highlight the presence of a selection bias and high heterogeneity, which hampers inferential analysis when comparing both techniques.