Hemodynamic Analysis of Postoperative Rupture of Unruptured Intracranial Aneurysms after Placement of Flow-Diverting Stents: A Matched Case-Control Study

Abstract

BACKGROUND AND PURPOSE: Postoperative rupture of intracranial aneurysm has been reported as a fatal complication after flow-diverter placement. We assessed several hemodynamic variables to explore risk factors in the postoperative rupture process. MATERIALS AND METHODS:We enrolled 10 patients with intracranial aneurysms, treated with flow diverters between September 2014 and December 2018, who experienced postoperative aneurysm rupture (postoperative aneurysm rupture group). We matched these subjects 1:2 with 20 patients with postoperative unruptured (postoperative unruptured group) intracranial aneurysms based on clinical and morphologic factors. Using computational fluid dynamics, we assessed hemodynamic changes pre-and posttreatment between the 2 groups on a number of qualitative and quantitative parameters. RESULTS:In the postoperative aneurysm rupture group, the proportion of patients with aneurysms with an unstable flow pattern increased to 60.0% after treatment, while the proportion in the postoperative unruptured group decreased to 20.0%, a significant difference between the 2 groups (P = .028). Energy loss in the postoperative unruptured group decreased after treatment but increased in the postoperative aneurysm rupture group. The reduction ratio of energy loss showed a significant difference between the 2 groups (22.73% 6 53.59% for postoperative unruptured versus À158.81% 6 183.95% for postoperative aneurysm rupture, P = .02). Other parameters and changes of pre-and posttreatment hemodynamic parameters showed no significant difference between 2 groups. CONCLUSIONS: Compared with pretreatment, unstable flow pattern and higher energy loss after Pipeline Embolization Device placement for intracranial aneurysm may be the important hemodynamic risk factors related to delayed aneurysm rupture. ABBREVIATIONS: CFD¼ computational fluid dynamics; EL ¼ energy loss; IA ¼ intracranial aneurysm; LSA ¼ low wall shear stress area; OG ¼ occlusion grade; OSI ¼ oscillatory shear index; POR ¼ postoperative ruptured; POU ¼ postoperative unruptured; RRT ¼ relative residual time; TAWSS ¼ time-averaged wall shear stress; WSS ¼ wall shear stress

Imbalanced flow changes of distal arteries: An important factor in process of delayed ipsilateral parenchymal hemorrhage after flow diversion in patients with cerebral aneurysms

“…26 Li et al. 13 found that hemodynamics played an important role in postoperative aneurysm rupture after flow diversion, and thus we speculated that hemodynamic factors might also play an important role in the process of DIPH occurrence.…”

“…PSM is a recognized method of balancing covariates in two groups to reduce selection bias. 13 All quantitative hemodynamic parameters were presented as means and standard deviations. For qualitative data, the χ2 test or the Fisher’s exact test was used to compare the differences between two groups.…”

“…Several studies have suggested that hemodynamic changes in the distal artery after PED deployment might play an important role in the occurrence of DIPH. 11–13 However, information on hemodynamics in relation to DIPH after PED treatment is limited. In this study, computational fluid dynamics (CFD) and advanced virtual stenting technique were used to explore the hemodynamics of the distal branch associated with DIPH.…”

A Dissipation Function–Based Method for Calculating the Energy Loss of Intracranial Aneurysms

“…Moreover, we also compared the EL of aneurysm sac calculated by the two methods ( Figure 8B ). In previous studies in which the Bernoulli equation–based method was applied ( 6 , 12 , 14 – 17 ), the EL of aneurysm sac (EL beAN ) was characterized by the EL changes caused by the aneurysm formation, namely, the difference of EL be between with-aneurysm and non-aneurysm models. In our method, the EL of aneurysm sac (EL dfAN ) can be obtained by integrating DF over aneurysmal domain.…”

p64 flow diverter: Results in 108 patients from a single center

“…Some suggest that altered hemodynamics induced by the flow diverter increases the wall stress to the aneurysm. 29 Others favor the theory that thrombus formed in the aneurysm releases enzymes that cause lysis of the aneurysm wall.…”