Association of Hemodynamic Factors With Intracranial Aneurysm Formation and Rupture

Neurosurgery ◽  
2015 ◽  
Vol 78 (4) ◽  
pp. 510-520 ◽  
Author(s):  
Anil Can ◽  
Rose Du

Abstract BACKGROUND: Recent evidence suggests a link between the magnitude and distribution of hemodynamic factors and the formation and rupture of intracranial aneurysms. However, there are many conflicting results. OBJECTIVE: To quantify the effect of hemodynamic factors on aneurysm formation and their association with ruptured aneurysms. METHODS: We performed a systematic review and meta-analysis through October 2014. Analysis of the effects of hemodynamic factors on aneurysm formation was performed by pooling the results of studies that compared geometrical models of intracranial aneurysms and “preaneurysm” models where the aneurysm was artificially removed. Furthermore, we calculated pooled standardized mean differences between ruptured and unruptured aneurysms to quantify the association of hemodynamic factors with ruptured aneurysms. Standard PRISMA guidelines were followed. RESULTS: The hemodynamic factors that showed high positive correlations with location of aneurysm formation were high wall shear stress (WSS) and high gradient oscillatory number, with pooled proportions of 78.8% and 85.7%, respectively. Positive correlations were largely seen in bifurcation aneurysms, whereas negative correlations were seen in sidewall aneurysms. Mean and normalized WSS were significantly lower and low shear area significantly higher in ruptured aneurysms. CONCLUSION: Pooled analyses of computational fluid dynamics models suggest that an increase in WSS and gradient oscillatory number may contribute to aneurysm formation, whereas low WSS is associated with ruptured aneurysms. The location of the aneurysm at the bifurcation or sidewall may influence the correlation of these hemodynamic factors.

2013 ◽  
Vol 19 (1) ◽  
pp. 43-48 ◽  
Author(s):  
K. Wang ◽  
Y. Sun ◽  
A-M. Li

Despite experience and technological improvements, stent-assisted coiling for intracranial aneurysms still has inherent risks. We evaluated peri-procedural morbidity and mortality associated with stent-assisted coiling for intracranial aneurysms. Patients with cerebral aneurysms that were broad-based (>4 mm) or had unfavorable dome/neck ratios (<1.5) were enrolled in this study between February and November 2011 at our center. Aneurysms were treated with the self-expanding neurovascular stents with adjunctive coil embolization. Seventy-two consecutive patients (27 men and 45 women; 22–78 years of age; mean age, 52.8 years) underwent 13 procedures for 13 ruptured aneurysms and 64 procedures for 73 unruptured aneurysms. Nine [11.7%, 95% CI(4.5%–18.9%)] procedure-related complications occurred: one and eight with initial embolization of ruptured and unruptured aneurysms, respectively. Complications included six acute in-stent thromboses, one spontaneous stent migration, one post-procedural aneurysm rupture, and one perforator occlusion. Three complications had no neurologic consequences. Two caused transient neurologic morbidity, two persistent neurologic morbidity, and two death. Procedure-related neurologic morbidity and mortality rates, respectively, were as follows: overall, 5.2% (95%CI, 0.2%–10.2%) and 2.6% (95%CI, 0%–6.2%); ruptured aneurysms, 7.7% (95%CI, 0%–36%) and 0% (95%CI, 0%–25%); unruptured aneurysms, 4.7% (95%CI, 0%–9.9%) and 3.1% (95%CI, 0%–7.3%). Combined procedure-related morbidity and mortality rates for ruptured and unruptured aneurysms were 7.7% (95%CI, 1.7%–13.7%) and 7.8% (95%CI, 1.8%–13.8%), respectively. Stent-assisted coiling is an attractive option for intracranial aneurysms. However, stent-assisted coiling for unruptured aneurysms is controversial for its comparable risk to natural history.


2010 ◽  
Vol 16 (3) ◽  
pp. 231-239 ◽  
Author(s):  
L.M. Pyysalo ◽  
L.H. Keski-Nisula ◽  
T.T. Niskakangas ◽  
V.J. Kähärä ◽  
J.E. Öhman

Long-term follow-up studies after endovascular treatment for intracranial aneurysm are still rare and inconclusive. The aim of this study was to assess the long-term clinical and angiographic outcome of patients with endovascularly treated aneurysms. The clinical outcome of all 185 patients with endovascularly treated aneurysms were analyzed and 77 out of 122 surviving patients were examined with MRI and MRA nine to 16 years (mean 11 years) after the initial endovascular treatment. Sixty-three patients were deceased at the time of follow-up. The cause of death was aneurysm-related in 34 (54%) patients. The annual rebleeding rate from the treated aneurysms was 1.3% in the ruptured group and 0.1% in the unruptured group. In long-term follow-up MRA 18 aneurysms (53%) were graded as complete, 11 aneurysms (32%) had neck remnants and five aneurysms (15%) were incompletely occluded in the ruptured group. The occlusion grade was lower in the unruptured group with 20 aneurysms (41%) graded as complete, 11 (22%) had neck remnants and 18 (37%) were incomplete. However, only three aneurysms were unstable during the follow-up period and needed retreatment. Endovascular treatment of unruptured aneurysms showed incomplete angiographic outcome in 37% of cases. However, the annual bleeding rate was as low as 0.1%. Endovascular treatment of ruptured aneurysms showed incomplete angiographic outcome in 15% of cases and the annual rebleeding rate was 1,3%.


2019 ◽  
Vol 131 (4) ◽  
pp. 1262-1268 ◽  
Author(s):  
Shunsuke Omodaka ◽  
Hidenori Endo ◽  
Kuniyasu Niizuma ◽  
Miki Fujimura ◽  
Takashi Inoue ◽  
...  

OBJECTIVERecent MR vessel wall imaging studies have indicated intracranial aneurysms in the active state could show circumferential enhancement along the aneurysm wall (CEAW). While ruptured aneurysms frequently show CEAW, CEAW in unruptured aneurysms at the evolving state (i.e., growing or symptomatic) has not been studied in detail. The authors quantitatively assessed the degree of CEAW in evolving unruptured aneurysms by comparing it separately to that in stable unruptured and ruptured aneurysms.METHODSA quantitative analysis of CEAW was performed in 26 consecutive evolving aneurysms using MR vessel wall imaging. Three-dimensional T1-weighted fast spin echo sequences were obtained before and after contrast media injection, and the contrast ratio of the aneurysm wall against the pituitary stalk (CRstalk) was calculated as the indicator of CEAW. Aneurysm characteristics of evolving aneurysms were compared with those of 69 stable unruptured and 67 ruptured aneurysms.RESULTSThe CRstalk values in evolving aneurysms were significantly higher than those in stable aneurysms (0.54 vs 0.34, p < 0.0001), and lower than those in ruptured aneurysms (0.54 vs 0.83, p < 0.0002). In multivariable analysis, CRstalk remained significant when comparing evolving with stable aneurysms (odds ratio [OR] 12.23, 95% confidence interval [CI] 3.53–42.41), and with ruptured aneurysms (OR 0.083, 95% CI 0.022–0.310).CONCLUSIONSThe CEAW in evolving aneurysms was higher than those in stable aneurysms, and lower than those in ruptured aneurysms. The degree of CEAW may indicate the process leading to rupture of intracranial aneurysms, which can be useful additional information to determine an indication for surgical treatment of unruptured aneurysms.


Neurosurgery ◽  
2005 ◽  
Vol 57 (6) ◽  
pp. 1096-1102 ◽  
Author(s):  
YiLing Cai ◽  
Laurent Spelle ◽  
Huan Wang ◽  
Michel Piotin ◽  
Charbel Mounayer ◽  
...  

Abstract OBJECTIVE: With a globally aging population, it is imperative to develop specific treatment strategies for intracranial aneurysms in the elderly. However, the optimal management of intracranial aneurysms in the elderly remains controversial, particularly for the unruptured aneurysms. Although endovascular treatment is increasingly being used for the management of aneurysms, large endovascular series in the elderly population are relatively lacking, especially with regard to the unruptured aneurysms. We present our single-center endovascular experience in treating intracranial aneurysms in 63 consecutive patients 70 years of age and older. METHODS: Between November 1998 and December 2003, among a total of 990 patients with intracranial aneurysms treated endovascularly at our center, 63 patients (6%) were 70 years of age or older. Forty-one patients presented with subarachnoid hemorrhage (SAH), and 22 presented with symptomatic unruptured aneurysms. A total of 84 aneurysms were detected in these 63 patients. Only those responsible for either the subarachnoid hemorrhage or clinical symptoms (68 aneurysms) were treated. The aneurysm characteristics, endovascular procedures and techniques, angiographic and clinical outcomes, and complications were reviewed. RESULTS: Selective embolization failed in three aneurysms (4%). In the remaining 65 aneurysms, complete occlusion was achieved in 33 aneurysms (51%), neck remnant was observed in 17 aneurysms (27%), and residual aneurysmal filling was observed in six aneurysms (9%). Parent vessel occlusion was used in the treatment of nine aneurysms (13%). Thirteen procedure-related complications occurred (19%), six of which resulted in clinical complications (9%). Nine deaths (14%) occurred; three (5%) were directly related to the endovascular procedures, and six (9%) were related to the medical complications of SAH. The remaining 54 patients had a mean clinical follow-up time of 13 months (range, 1–47 mo). Ninety-one percent (20 out of 22) of the patients with unruptured aneurysms and 89% (25/28) of the patients with low-grade (Hunt and Hess Grade I and II) ruptured aneurysms achieved excellent outcomes (modified Rankin Scale score, 0–1), whereas 77% (10 out of 13) of the patients with high-grade (Hunt and Hess Grade ≥ III) ruptured aneurysms either died or had very poor outcomes (modified Rankin Scale score, 4–5). Angiographic follow-up (mean, 11 mo; range, 3–38 mo) was obtained in 34 of the 54 living patients (63%). Two aneurysms demonstrated minor changes that required no further treatment (5%). Five aneurysms showed major recurrences (17%), all of which were successfully retreated endovascularly. CONCLUSION: The elderly patients should merit strong consideration for endovascular treatment of both ruptured and symptomatic unruptured intracranial aneurysms. However, in elderly patients with high-grade subarachnoid hemorrhage, morbidity and mortality rates remain high.


2004 ◽  
Vol 101 (6) ◽  
pp. 1018-1025 ◽  
Author(s):  
Luigi Pentimalli ◽  
Andrea Modesti ◽  
Andrea Vignati ◽  
Enrico Marchese ◽  
Alessio Albanese ◽  
...  

Object. Mechanisms involved in the rupture of intracranial aneurysms remain unclear, and the literature on apoptosis in these lesions is extremely limited. The hypothesis that apoptosis may reduce aneurysm wall resistance, thus contributing to its rupture, warrants investigation. The authors in this study focused on the comparative evaluation of apoptosis in ruptured and unruptured intracranial aneurysms. Peripheral arteries in patients harboring the aneurysms and in a group of controls were also analyzed. Methods. Between September 1999 and February 2002, specimens from 27 intracranial aneurysms were studied. In 13 of these patients apoptosis was also evaluated in specimens of the middle meningeal artery (MMA) and the superficial temporal artery (STA). The terminal deoxynucleotidyl transferase—mediated deoxyuridine triphosphate nick-end labeling technique was used to study apoptosis via optical microscopy; electron microscopy evaluation was performed as well. Apoptotic cell levels were related to patient age and sex, aneurysm volume and shape, and surgical timing. Significant differences in apoptosis were observed when comparing ruptured and unruptured aneurysms. High levels of apoptosis were found in 88% of ruptured aneurysms and in only 10% of unruptured lesions (p < 0.001). Elevated apoptosis levels were also detected in all MMA and STA specimens obtained in patients harboring ruptured aneurysms, whereas absent or very low apoptosis levels were observed in MMA and STA specimens from patients with unruptured aneurysms. A significant correlation between aneurysm shape and apoptosis was found. Conclusions. In this series, aneurysm rupture appeared to be more related to elevated apoptosis levels than to the volume of the aneurysm sac. Data in this study could open the field to investigations clarifying the causes of aneurysm enlargement and rupture.


2019 ◽  
Vol 26 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Jens J Froelich ◽  
Nicholas Cheung ◽  
Johan AB de Lange ◽  
Jessica Monkhorst ◽  
Michael W Carr ◽  
...  

Objective Incomplete aneurysm occlusions and re-treatment rates of 52 and 10–30%, respectively, have been reported following endovascular treatment of intracranial aneurysms, raising clinical concerns regarding procedural efficacy. We compare residual, recurrence and re-treatment rates subject to different endovascular techniques in both ruptured and unruptured intracranial aneurysms at a comprehensive state-wide tertiary neurovascular centre in Australia. Methods Medical records, procedural and follow-up imaging studies of all patients who underwent endovascular treatment for intracranial aneurysms between July 2010 and July 2017 were reviewed retrospectively. Residuals, recurrences and re-treatment rates were assessed regarding initial aneurysm rupture status and applied endovascular technique: primary coiling, balloon- and stent-assisted coiling and flow diversion. Results Among 233 aneurysms, residual, recurrence and re-treatment rates were 27, 11.2 and 9.4%, respectively. Compared with unruptured aneurysms, similar residual and recurrence (p > .05), but higher re-treatment rates (4.5% vs. 19%; p < .001) were found for ruptured aneurysms. Residual, recurrence and re-treatment rates were: 13.3, 16 and 12% for primary coiling; 12, 12 and 10.7% for balloon-assisted coiling; 14.9, 7.5 and 4.5% for stent-assisted coiling; 91.9, 0 and 5.4% for flow diversion. Stent-assistance and flow-diversion were associated with lower recurrence and re-treatment rates, when compared with primary- and balloon-assisted coiling (p < .05). Conclusions Residuals and recurrences after endovascular treatment of intracranial aneurysms are less common than previously reported. Stent assistance and flow diversion seem associated with reduced recurrence- and re-treatment rates, when compared with primary- and balloon-assisted coiling. Restrained use of stents in ruptured aneurysms may be a contributing factor for higher recurrence/retreatment rates compared to unruptured aneurysms.


Author(s):  
Xin-Yu Li ◽  
Cong-Hui Li ◽  
Ji-Wei Wang ◽  
Jian-Feng Liu ◽  
Hui Li ◽  
...  

Abstract Purpose The purpose of the study was to investigate the safety and efficacy of endovascular embolization of ruptured intracranial aneurysms within 72 hours of subarachnoid hemorrhage (SAH). Materials and methods Patients with intracranial aneurysms treated with embolization were divided into group A (n = 277), patients with ruptured aneurysms treated within 72 hours of SAH; group B (n = 138), patients with ruptured aneurysms treated beyond 72 hours; and group C (n = 93), patients with unruptured aneurysms. Results Embolization was successful in all but four patients (99.2%). The periprocedural complication rate was 36.2% in group B, significantly (p < 0.05) greater than that in group A (24.5%) or group C (11.8%). The rebleeding rate was 9.7% (6/62 patients) in groups A and B after embolization and only 0.3% (1/346 patients) in aneurysms with total or subtotal occlusion. Of these three groups of patients, 69.7% in group A, 58.7% in group B, and 76.3% in group C achieved Glasgow Outcome Scale (GOS) score of 5 or modified Rankin Scale (mRS) score of 0– to 1 at discharge. A significant difference (p < 0.05) existed in the clinical outcome between the three groups. The percentages of patients without deficits (GOS 5 or mRS 0–1) and slight disability (mRS 2) were 80.2% in group A, 81.2% in group B, and 96.7% in group C. The mortality rate was 4.3% (12/277 patients) in group A and 7.2% (10/138 patients) in group B with no significant (p = 0.21) difference. Follow-up was performed at 3 to 54 months (mean 23.2), and the recanalization rate was 28.6% (32/112 patients) in group A, 22.4% (11/49 patients) in group B, and 28.6% (16/56 patients) in group C, with no significant differences (p = 0.15). Hydrocephalus occurred in 30.5% (39/128 patients) in group B, which was significantly (p < 0.01) greater than that in group A (9.4%) or group C (2.2%). Conclusion Early embolization of ruptured cerebral aneurysms within 72 hours of rupture is safe and effective and can significantly decrease periprocedural complications compared with management beyond 72 hours. Timely management of cisternal and ventricular blood can reduce hydrocephalus incidence and improve prognosis.


Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Maxim Mokin ◽  
Muhammad Waqas ◽  
Andrew Gong ◽  
Felix Chin ◽  
Hamid Rai ◽  
...  

Abstract INTRODUCTION Size of the cerebral aneurysms is given a considerable weightage in deciding on the management for cerebral aneurysms. Literature on the size of ruptured aneurysms is heterogenous and often contradictory. The purpose of this systematic review was to determine the size of ruptured aneurysms with respect to location. METHODS We conducted a systematic review of literature. The protocol was registered with PROSPERO. PubMed, Cochrane, CiNAHL, and EMBASE databases were reviewed All the studies reporting the mean size of consecutive patients with intracranial aneurysms were included. Studies that did not report mean with standard deviations or were restricted to the study of small or large aneurysms were excluded. Heterogeneity was assessed using I2 and random effect model was used to perform metanalysis of the data. Pooled mean and standard deviation were calculated for overall size and subgroup of aneurysms at a specific location. R statistical package was used for analysis. RESULTS A total of 64 studies with 10 873 intracranial aneurysms were included in the meta-analysis. Pooled mean ruptured intracranial aneurysm size in 64 studies was 6.99 ± 4.14 mm. Mean size for anterior communicating artery was reported by 9 studies, 1118 aneurysms with a pooled mean of 4.65 ± 2.12 mm. Posterior communicating artery aneurysm size was reported in 10 studies with pooled mean of 6.43 ± 2.41 mm. Nine studies reported mean size of middle cerebral artery. The pooled value was 8.90 ± 4.91 mm. Pooled mean size for posterior inferior cerebellar artery was 4.09 ± 1.63 mm. CONCLUSION Mean size of ruptured intracranial aneurysms reported by most studies is less than 7.0 mm and varies with the location of the aneurysm. Morphological and hemodynamic factors other than size may be more important in determining rupture risk.


Neurosurgery ◽  
2012 ◽  
Vol 70 (5) ◽  
pp. 1114-1124 ◽  
Author(s):  
Robert T. Wicks ◽  
Gustavo Pradilla ◽  
Shaan M. Raza ◽  
Uri Hadelsberg ◽  
Alexander L. Coon ◽  
...  

Abstract BACKGROUND: Somatosensory evoked potential (SSEP) monitoring is used during intracranial aneurysm surgery to track the effects of anesthesia, surgical manipulation, and temporary clipping. OBJECTIVE: To present the outcomes of 663 consecutive patients (691 cases) treated surgically for intracranial aneurysms who underwent intraoperative SSEP monitoring and to analyze the sensitivity and specificity of significant SSEP changes in predicting postoperative stroke. METHODS: Of 691 surgeries analyzed, 403 (391 anterior circulation, 12 posterior circulation) were unruptured aneurysms and 288 (277 anterior, 11 posterior) were ruptured. Postoperatively, symptomatic patients underwent computed tomography imaging. Positive predictive value, negative predictive value, sensitivity, and specificity were calculated with a Fisher exact test (2-tailed P value). RESULTS: Changes in SSEP occurred in 45 of 691 cases (6.5%): 16 of 403 (4.0%) in unruptured aneurysms and 29 of 288 (10%) in ruptured aneurysms. In unruptured aneurysms, reversible SSEP changes were associated with a 20% stroke rate, but irreversible changes were associated with an 80% stroke rate. In ruptured aneurysms, however, reversible changes were associated with a 12% stroke rate, and irreversible changes were associated with a 42% stroke rate. The overall accuracy of SSEP changes in predicting postoperative stroke was as follows: positive predictive value, 30%; negative predictive value, 94%; sensitivity, 25%; and specificity, 95%. CONCLUSION: Intraoperative SSEP changes are more reliable in unruptured aneurysm cases than in ruptured cases. Whereas irreversible changes in unruptured cases were associated with an 80% stroke rate, such changes in ruptured cases did not have any adverse ischemic sequelae in 58% of patients. This information is helpful during the intraoperative assessment of reported SSEP changes.


Neurosurgery ◽  
2017 ◽  
Vol 83 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Isabel C Hostettler ◽  
Varinder S Alg ◽  
Nichole Shahi ◽  
Fatima Jichi ◽  
Stephen Bonner ◽  
...  

Abstract BACKGROUND Only a minority of intracranial aneurysms rupture to cause subarachnoid hemorrhage. OBJECTIVE To test the hypothesis that unruptured aneurysms have different characteristics and risk factor profiles compared to ruptured aneurysms. METHODS We recruited patients with unruptured aneurysms or aneurysmal subarachnoid hemorrhages at 22 UK hospitals between 2011 and 2014. Demographic, clinical, and imaging data were collected using standardized case report forms. We compared risk factors using multivariable logistic regression. RESULTS A total of 2334 patients (1729 with aneurysmal subarachnoid hemorrhage, 605 with unruptured aneurysms) were included (mean age 54.22 yr). In multivariable analyses, the following variables were independently associated with rupture status: black ethnicity (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.29-4.56, compared to white) and aneurysm location (anterior cerebral artery/anterior communicating artery [OR 3.21; 95% CI 2.34-4.40], posterior communicating artery [OR 3.92; 95% CI 2.67-5.74], or posterior circulation [OR 3.12; 95% CI 2.08-4.70], compared to middle cerebral artery). The following variables were inversely associated with rupture status: antihypertensive medication (OR 0.65; 95% CI 0.49-0.84), hypercholesterolemia (0.64 OR; 95% CI 0.48-0.85), aspirin use (OR 0.28; 95% CI 0.20-0.40), internal carotid artery location (OR 0.53; 95% CI 0.38-0.75), and aneurysm size (per mm increase; OR 0.76; 95% CI 0.69-0.84). CONCLUSION We show substantial differences in patient and aneurysm characteristics between ruptured and unruptured aneurysms. These findings support the hypothesis that different pathological mechanisms are involved in the formation of ruptured aneurysms and incidentally detected unruptured aneurysms. The potential protective effect of aspirin might justify randomized prevention trials in patients with unruptured aneurysms.


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