Assessment of the Dynamic Reduction in Volume and Prolonged Shrinkage of Giant and Symptomatic Cerebral Aneurysms Following Combined Endovascular Interventions

Large (with a diameter of ≥15 mm) and giant (with a diameter of ≥25 mm) intracranial aneurysms represent a distinct subset within the spectrum of cerebral aneurysms, necessitating intricate treatment considerations given their challenging nature and unfavorable natural course. Traditionally characterized by gradual enlargement, these aneurysms frequently progress to rupture, leading to substantial morbidity and higher mortality rates. Additionally, these aneurysms commonly induce peri-aneurysmal edematous changes in the neighboring brain regions. This impact extends to cranial nerves, potentially resulting in functional compromise due to compression of the surrounding brain tissue. The degree of functional impairment is contingent upon the distribution of the cranial nerves within the cerebral circulation.Current treatment options for large and giant cerebral aneurysms involve endovascular interventions employing endoluminal flow diverter stents, with or without coils, and a hybrid approach of combining bypass anastomosis and parent artery occlusion using the endovascular method. These methods have consistently demonstrated high rates of complete aneurysm occlusion and maintain an acceptable safety profile.

2. Previous studies at the National Centre for Neurosurgery. "Management of giant internal carotid aneurysm by extracranial-intracranial bypass and flow diverter stent" and "Early and midterm results of treatment of giant internal carotid artery paraclinoid aneurysms with trapping and flow diverters" has previously been studied and published. The studies included patients who underwent treatment at the Vascular and Functional Neurosurgery Department, National Centre for Neurosurgery, Astana, Kazakhstan.

3. Research Gap and Novelty of a Research Project. Despite the favorable outcomes observed with treatment methods such as endovascular interventions employing endoluminal flow diverter stents, either with or without coils, and a hybrid approach involving bypass anastomosis and parent artery occlusion using the endovascular method, there is a notable lack of comprehensive data on aneurysmal sac shrinkage and complete obliteration rates following these treatments. To address this gap, this study will evaluate the treatment effects specifically on aneurysmal sac shrinkage and volume reduction - crucial factors for a comprehensive assessment of the effectiveness of these interventions.

In parallel, other studies have delved into investigating aneurysm shrinkage following the use of flow diverters with and without coils. Nevertheless, it is crucial to emphasize that these studies failed to take into account the extent of aneurysm closure evaluated using the Raymond Roy scale, as well as data on the deployment of stents assessed using the O'Kelly-Marotta grading system. Additionally, most of the publications are limited to case descriptions only. Notably, these cases did not include an examination of the packing density of the aneurysm. Furthermore, there is a lack of evidence regarding the role of inflammatory factors in the reduction of brain aneurysms following the deployment of flow diverters. In contrast, studies on patients with abdominal aortic aneurysms have explored the influence of preoperative inflammatory markers, such as Neutrophil-to-Lymphocyte (NLR) and Platelet-to-Lymphocyte (PLR) ratios, on post-endovascular aneurysm repair (EVAR) sac shrinkage. These studies have underscored the substantial impact of these inflammatory markers on aneurysm shrinkage following stent placement. Consequently, this prompts consideration for potential research on these variables in cerebral vascular aneurysm model studies.

In summary, while the flow-diverter treatment process typically spans 6 months to a year with the objective of complete aneurysm elimination, there remains a significant lack of data regarding the extended clinical outcomes of flow-diverter therapy, particularly in the context of large-thrombosed aneurysms.