Impact of aneurysm morphology on aneurysmal subarachnoid hemorrhage severity, cerebral infarction and functional outcome

Objective: Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high morbidity. The objective was to evaluate, whether specific morphological aneurysm characteristics could serve as predictive values for aSAH severity, disease-related complications and clinical outcome.

Methods: A total of 453 aSAH patients (mean age: 54.9 ± 13.8 years, mean aneurysm size: 7.5 ± 3.6 mm) treated at a single center were retrospectively included. A morphometric analysis was performed based on angiographic image sets, determining aneurysm location, aneurysm size, neck width, aneurysm size ratios, aneurysm morphology and vessel size. The following outcome measures were defined: World Federation of Neurosurgical Societies (WFNS) grade 4 and 5, Fisher grade 4, vasospasm, cerebral infarction and unfavorable functional outcome.

Results: Regarding morphology parameters, aneurysm neck width was an independent predictor for Fisher 4 hemorrhage (OR: 1.1, 95%CI: 1.0-1.3, p = 0.048), while dome width (OR: 0.92, 95%CI: 0.86-0.97, p = 0.005) and internal carotid artery location (OR: 2.1, 95%CI: 1.1-4.2, p = 0.028) predicted vasospasm. None of the analyzed morphological characteristics prognosticated functional outcome. Patient age (OR: 0.95, 95%CI: 0.93-0.96, p < 0.001), WFNS score (OR: 4.8, 95%CI: 2.9-8.0, p < 0.001), Fisher score (OR: 2.3, 95%CI: 1.4-3.7, p < 0.001) and cerebral infarction (OR: 4.5, 95%CI: 2.7-7.8, p < 0.001) were independently associated with unfavorable outcome.

Conclusions: The findings indicate a correlation between aneurysm morphology, Fisher grade and vasospasm. Further studies will be required to reveal an independent association of aneurysm morphology with cerebral infarction and functional outcome.