Intracranial aneurysm wall (in)stability–current state of knowledge and clinical perspectives

Abstract

Intracranial aneurysm (IA), a local outpouching of cerebral arteries, is present in 3 to 5% of the population. Once formed, an IA can remain stable, grow, or rupture. Determining the evolution of IAs is almost impossible. Rupture of an IA leads to subarachnoid hemorrhage and affects mostly young people with heavy consequences in terms of death, disabilities, and socioeconomic burden. Even if the large majority of IAs will never rupture, it is critical to determine which IA might be at risk of rupture. IA (in)stability is dependent on the composition of its wall and on its ability to repair. The biology of the IA wall is complex and not completely understood. Nowadays, the risk of rupture of an IA is estimated in clinics by using scores based on the characteristics of the IA itself and on the anamnesis of the patient. Classification and prediction using these scores are not satisfying and decisions whether a patient should be observed or treated need to be better informed by more reliable biomarkers. In the present review, the effects of known risk factors for rupture, as well as the effects of biomechanical forces on the IA wall composition, will be summarized. Moreover, recent advances in high-resolution vessel wall magnetic resonance imaging, which are promising tools to discriminate between stable and unstable IAs, will be described. Common data elements recently defined to improve IA disease knowledge and disease management will be presented. Finally, recent findings in genetics will be introduced and future directions in the field of IA will be exposed.

Structural Fragility of Cerebral Aneurysms: A Comparative Analysis of Unruptured & Ruptured Aneurysms

“…(Kormanz). Along the same lines, Morel et al found that unruptured intracranial aneurysmal walls display a significantly lower expression of inflammatory cluster differentiation (CD68) positive cells, suggestive of macrophages, thereby lending support to the role of a sustained macrophage influx as critical effectors in progressive aneurysmal remodeling, growth and subsequent rupture [48]. In addition to direct histological evidence documenting a sparse inflammatory cell invasion in unruptured intracranial aneurysmal models, radiologic studies further substantiate such observations by documenting changes in aneurysmal wall enhancement.…”

Challenges in identifying ruptured aneurysms in cases of multiple aneurysms: Utilizing MRI with contrast for surgical planning—A case report

“…Incorporating vascular wall MRI into the diagnostic algorithm might greatly improve the ability to identify the site of the ruptured aneurysm, hence optimizing the surgical strategy to minimize further bleeding and optimize patient outcomes. 16 , 17…”

Impact of disrupted cyclic stretch in intracranial aneurysms: Insights from endothelial cell transcriptomic dataset

“…The pathogenesis of intracranial aneurysm (IA) is highly complex [1] . Several studies emphasized the role of wall shear stress (WSS) in endothelial cell (EC) dysfunction and IA initiation and growth [2] , [3] , [4] , [5] , [6] .…”