The Relationship of Morphological-Hemodynamic Characteristics, Inflammation, and Remodeling of Aneurysm Wall in Unruptured Intracranial Aneurysms

Abstract

Aneurysm wall remodeling (AWR) is an important pathological characteristic in aneurysm wall, which was characterized by abnormal histological structure and inflammation infiltration. In the present study, the aim is to determine the relationships of morphological-hemodynamic characteristics, inflammation, and AWR in intracranial aneurysms (IAs), as well as the pathological basis of morphological-hemodynamic predictors to achieve IA development. For this end, 113 unruptured IAs were prospectively collected from 110 cases. In addition, patient-specific computational fluid dynamics and geometry were adopted to determine hemodynamic and morphological parameters. Moreover, Hematoxylin-Eosin staining was performed to identify the AWR. By performing immunofluorescence, the inflammatory markers were detected. Masson staining was conducted to characterize the characteristics of atherosclerosis in aneurysm wall. To demonstrate the parameters regarding the AWR, a multivariate logistic analysis was conducted. Besides, correlation analyses were conducted to verify the relationship between morphological-hemodynamic and pathological characteristics. For 113 unruptured IAs, no difference was identified in baseline information. AWR was demonstrated in 92 (81.4%) IAs. To be specific, the aneurysm size (odds ratio (OR), 2.63; confidence interval (CI), 1.04-6.67; P = 0.041), size ratio (SR; OR, 1.95; CI, 1.38-2.76; P < 0.001), normalized wall shear stress average (NWSSA; OR, 0.05; CI, 0.01-0.15; P = 0.007), and relative resident time (RRT; OR, 1.28; CI, 1.07-1.53; P = 0.007) were proved as the factors of AWR. As revealed from the results of immunofluorescence, aneurysm size, SR, NWSSA, and RRT were significantly correlated with the level of inflammation in IA tissues. Furthermore, Masson staining revealed that atherosclerosis area in IA tissues and NWSSA was correlated with RRT. In this study, SR, NWSSA, and RRT were demonstrated as the risk factors of AWR. The mentioned parameters could also reflect the characteristics of inflammation and atherosclerosis in aneurysm wall as well. This study revealed that biomechanical stress and inflammation in aneurysm wall are correlated, which might suggest the pathological evidence of morphological-hemodynamic predictors for IA development.

Keywords: Aneurysm wall remodeling; Hemodynamics; Inflammation; Intracranial aneurysm; Morphology.