Prevalence and Characteristics of Unruptured Cerebral Aneurysms in Ischemic Stroke Patients

The rupture of an anterior communicating artery aneurysm does not associate with an asymmetry in the A1 or A2 arteries: a retrospective study of radiological features

BACKGROUND AND OBJECTIVES

Although the formation and rupture risk of an anterior communicating artery (ACoA) aneurysm has been the subject of many studies, no previous study has primarily searched for the relationship of the parent and daughter vessels and the impact of their size/diameter ratio on the potential rupture risk of an AcoA aneurysm. The objective of this study is to explore this link and to further analyse the surrounding vasculature of the anterior communicating artery aneurysm.

MATERIALS AND METHODS

We conducted a retrospective analysis of 434 patients: 284 patients with an ACoA aneurysm (121 unruptured and 162 ruptured) and 150 control patients without an ΑCoA aneurysm. Radiological angiography investigations were used to assess the diameter ratios of the parent vessels in addition to ACoA aneurysm morphology parameters.

RESULTS

When comparing the ruptured to the unruptured cases, we observed no significant difference in the parent or daughter vessel diameter ratios. Younger patient age (OR 0.96, p = 0.00) and a higher aneurysm size ratio (OR 1.10, p = 0.02) were of prognostic importance concerning the rupture risk of the aneurysm. The A1 diameter ratio and the A2 diameter were not statistically significant (OR 1.00, p = 0.99, and OR 3.38, p = 0.25 respectively).

CONCLUSIONS

In our study, we focused on asymmetry in the parent and daughter vessels as well as traditional ACoA aneurysm morphological characteristics. We were able to label younger patient age and a greater size ratio as independent prognostic factors for ACoA aneurysm rupture. We were unable to label parent and daughter vessel asymmetry as prognostic factors. To validate our findings, parent and daughter vessel asymmetry should be subjected to future prospective studies.

Intracranial aneurysms in patients with acute ischemic stroke prevalence and influence on mechanical thrombectomy over 14 years in a tertiary-care center

INTRODUCTION

The prevalence of intracranial aneurysms (IA) in patients with acute ischemic stroke (AIS) requiring mechanical thrombectomy (MT) is unclear.

OBJECTIVE

To describe the prevalence of IA in patients with AIS and their influence on MT.

MATERIALS & METHODS

This is a retrospective cohort study on all patients admitted with a diagnosis of AIS from January 2008 to March 2022 at a tertiary academic center. The records were reviewed for demographic, clinical, imaging, and outcomes data. Only patients who had CTA at admission were included in this analysis.

RESULTS

Among 2265 patients admitted with AIS, this diagnosis was confirmed in 2113 patients (93.3 %). We included 1111 patients (52.6 %) who had head CTA and 321 (28.9 %) who underwent MT. The observed prevalence of aneurysms on CTA was 4.5 % (50/1111 patients), and 8 (16 %) had multiple aneurysms. MT was performed in 7 patients harboring IAs: 6 ipsilateral (5 proximal and 1 distal to the occlusion)and 1 contralateral aneurysm.. The patient with a contralateral aneurysm had a TICI 2B score In patients with ipsilateral aneurysms, TICI 2B or 3 was achieved in 3 cases (50 %), which is significantly lower than historical control of MT (91.6 %) without IA (p = 0.01). No aneurysms ruptured during MT. The aneurysm noted distal to the occlusion was mycotic.

CONCLUSION

In this analysis, the observed prevalence of IA in patients with AIS was 4.5%. Ipsilateral aneurysms (proximal or distal to the occlusion site) deserve particular attention, given the potential risk of rupture during MT. Aneurysms located distal to the occlusion were mycotic and the rate of recanization in patients with ipsilateral aneurysms was low compared to historical controls. Further studies are needed to improve the outcomes in patients with IA requiring MT.

Assessing the risk of intracranial aneurysm rupture using computational fluid dynamics: a pilot study

Objective

This study compared 2 representative cases with ruptured aneurysms to explore the role of hemodynamic and morphological parameters in evaluating the rupture risk of intracranial aneurysms (IAs).

Methods

CTA and 3-dimensional rotational angiography (3DRA) of 3 IAs in 2 patients were retrospectively analyzed in this study. Hemodynamics and morphological parameters were compared between a ruptured IA and an unruptured IA in case1, and between before and after aneurysm rupture in case 2.

Results

In case 1, the ruptured aneurysm had larger morphological parameters including size ratio (SR), aspect ratio (AR), aneurysm vessel angle (θF), Aneurysm inclination angle (θA), Undulation index (UI), Ellipticity index (EI), and Non-sphericity Index (NSI) than the unruptured aneurysm. And oscillatory shear index (OSI) is also larger. Higher rupture resemblance score (RRS) was shown in the ruptured aneurysm. In case 2, the aneurysm had one daughter sac after 2 years. Partial morphological and hemodynamic parameters including SR, AR, θF, θA, UI, EI, NSI, OSI, and relative residence time (RRT) increased, and normalized wall shear stress (NWSS) was significantly reduced. RRS increased during this period.

Conclusion

SR and OSI may have predictive values for the risk of intracranial aneurysm rupture. It is possible that WSS Changes before and after IA rupture, yet the influence of high or low WSS on growth and rupture of IA remains unclear. RRS is promising to be used in the clinical assessment of the rupture risk of IAs and to guide the formulation of treatment plans.

Prevalence and prognosis of acute ischemic stroke coexisting with unruptured intracranial aneurysms

Objectives

The prevalence of unruptured intracranial aneurysms (UIAs) in the acute ischemic stroke (AIS) cohort is probably higher than in the general population. This study investigated the prevalence of UIAs in AIS patients and the management risk and prognosis when treating AIS.

Methods

From January 2020 to January 2023, we conducted a single-center retrospective study at Tianjin Huanhu Hospital. Each patient underwent both brain MRI and MRA/CTA to diagnose AIS and UIAs. Clinical, radiologic, and therapeutic data during hospitalization and prognosis were analyzed. Propensity-score matching (PSM) was performed to evaluate the risk of in-hospital adverse events, unfavorable outcomes at discharge when receiving post-stroke treatment and stroke recurrence.

Results

In all, 2,181 AIS patients were included, of whom 270 had UIAs (12.4%; 95%CI 11.0-13.8%). From the unmatched and matched cohort, the incidence of in-hospital adverse events and unfavorable outcomes at discharge in patients with UIAs were not significantly different; the risk of stroke recurrence was significantly higher in patients with UIAs than in those without (unmatched: aHR, 1.71 [1.08-2.70]; matched: aHR, 2.55 [1.16-5.58]). Multivariable Cox regression models showed that aneurysm size and the presence of homoregional infarction associated with higher risk of recurrence (unmatched: aHR, 1.31 [1.21-1.41] and aHR, 3.50 [1.52-8.10]; matched: aHR, 1.28 [1.18-1.40]; p < 0.001 and aHR, 3.71 [1.12-12.34]).

Conclusion

The UIAs may not increase the risk of in-hospital adverse events and unfavorable outcomes at discharge in receiving post-stroke treatment, but it may associated with a high risk of stroke recurrence.

Prevalence and risk factors of unruptured intracranial aneurysms in ischemic stroke patients - A global meta-analysis

Background

Unruptured intracranial aneurysms (UIAs) have an estimated global prevalence of 2.8% in the adult population; however, UIA was identified among more than 10% of ischemic stroke patients. Many epidemiological studies and reviews have pointed to the presence of UIA among patients with ischemic stroke; yet, the extent of this association is not fully known. We performed a systematic review and meta-analysis to determine the prevalence of UIA in patients admitted to hospitals with ischemic stroke and transient ischemic attack (TIA) at both global and continental levels and evaluate factors associated with UIA in this population.

Methods

We identified, in five databases, all studies describing UIA in ischemic stroke and TIA patients between January 1, 2000, and December 20, 2021. Included studies were of observational and experimental design.

Results

Our search yielded 3581 articles of which 23 were included, with a total of 25,420 patients. The pooled prevalence of UIA was 5% (95% confidence interval [CI] = 4-6%) with stratified results showing 6% (95% CI = 4-9%), 6% (95% CI = 5-7%), and 4% (95% CI = 2-5%) in North America, Asia, and Europe, respectively. Significant risk factors were large vessel occlusion (odds ratios [OR] = 1.22, 95% CI = 1.01-1.47) and hypertension (OR = 1.45, 95% CI = 1.24-1.69), while protective factors were male sex (OR = 0.60, 95% CI = 0.53-0.68) and diabetes (OR = 0.82, 95% CI = 0.72-0.95).

Conclusion

The prevalence of UIA is notably higher in ischemic stroke patients than the general population. Physicians should be aware of common risk factors in stroke and aneurysm formation for appropriate prevention.

Risk Factors for Cerebral Aneurysm Rupture in Mongolia

Purpose

Identification of country-specific demographic, medical, lifestyle, and geoenvironmental risk factors for cerebral aneurysm rupture in the developing Asian country of Mongolia. First-time estimation of the crude national incidence of aneurysmal subarachnoid hemorrhage (aSAH).

Methods

A retrospective analysis of all intracranial digital subtraction angiographies (DSA) acquired in Mongolia during the 2‑year period 2016–2017 (1714 examinations) was performed. During this period, DSA was used as primary diagnostic imaging modality for acute severe neurological symptoms in the sole hospital nationwide dedicated to neurological patients. The catchment area of the hospital included the whole country. Patients with incidental and ruptured aneurysms were reviewed with respect to their medical history and living conditions. The data was used to install a Mongolian aneurysm registry.

Results

The estimated annual crude incidence of cerebral aneurysm rupture was 6.71 for the country of Mongolia and 14.53 per 100,000 persons for the capital region of Ulaanbaatar. Risk factors common in developed countries also applied for the Mongolian population: A medical history of hypertension, smoking or the presence of multiple aneurysms led to a higher relative risk of rupture. In contrast, female gender was not associated with a higher risk in this national cohort. Males pursuing a traditional nomadic living may exhibit a specifically high risk of rupture.

Conclusion

Disease management of over 200 individuals/year with aSAH constitutes a socioeconomic burden in Mongolia. Efforts to raise awareness of the risk factors hypertension and smoking among the Mongolian population are desirable. Measures to improve the nationwide availability of modern neurovascular treatment options are currently under consideration.

Prevalence, predictors and prognosis of incidental intracranial aneurysms in patients with suspected TIA and minor stroke: a population-based study and systematic review

INTRODUCTION

Unruptured intracranial aneurysms (UIAs) are common incidental imaging findings, but there are few data in patients with transient ischaemic attack (TIA)/stroke. The frequency of UIA might be higher due to shared risk factors, but rupture risk might be reduced by intensive secondary prevention. We determined the prevalence and prognosis of UIA in patients with suspected TIA/minor stroke.

METHODS

All patients referred to the population-based Oxford Vascular Study (2011-2020) with suspected TIA/minor stroke and non-invasive angiography were included. We determined the prevalence of incidental asymptomatic UIA and the risk of subsequent subarachnoid haemorrhage (SAH) by follow-up on intensive medical treatment, with guideline-based monitoring/management. We also did a systematic review of UIA prevalence/prognosis in cohorts with TIA/stroke.

FINDINGS

Among 2013 eligible patients, 95 (4.7%) had 103 previously unknown asymptomatic UIA. Female sex (OR 2.3, 95% CI 1.5 to 3.7), smoking (2.1, 1.2 to 3.6) and hypertension (1.6, 1.0 to 2.5) were independently predictive of UIA, with a prevalence of 11.1% in those with all three risk factors. During mean follow-up of 4.5 years, only one SAH occurred: 2.3 (95% CI 0.3 to 16.6) per 1000 person-years. We identified 19 studies of UIA in TIA/stroke cohorts (n=12 781), all with either symptomatic carotid stenosis or major acute stroke. The pooled mean UIA prevalence in patients with TIA/stroke was 5.1% (95% CI 4.8 to 5.5) and the incidence of SAH was 4.6 (95% CI 1.9 to 11.0) per 1000 person-years.

INTERPRETATION

The 5% prevalence of UIA in patients with confirmed TIA/minor stroke is likely higher than that in the general population. However, the risk of SAH on intensive medical treatment and guideline-based management/monitoring is low.

Incidental Unruptured Intracranial Aneurysms Do Not Impact Outcome in Patients With Acute Cerebral Infarction

Background: This study was to examine the patients with acute cerebral infarction (ACI) treated at a single center over 9 years and who underwent Unruptured intracranial aneurysm (UIA) screening by three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA), and to explore the factors associated with outcomes.

Methods: The outcome was the modified Rankin scale (mRS) score at 90 days after stroke onset. The outcome was classified into a good outcome (mRS score of 0–2 points) and poor outcome (mRS score of 3–6 points).

Results: UIAs were found in 260 (6.5%) of 4,033 patients with ACI; 2,543 (63.1%) had a good outcome, and 1,490 (36.9%) had a poor outcome. There was no difference in outcomes between the two groups (P = 0.785). The multivariable analysis showed that age (OR = 1.009, 95%CI: 1.003–1.014, P = 0.003), diabetes (OR = 1.179, 95%CI: 1.035–1.342, P = 0.013), ischemic stroke history (OR = 1.451, 95%CI: 1.256–1.677, P < 0.001), and baseline NIHSS score (OR = 1.034, 95%CI: 1.018–1.050, P < 0.001) were independently associated with the 90-day outcomes in patients with ACI. The presence of incidental UIA was not associated with outcomes after ACI.

Conclusions: Age, diabetes, ischemic stroke history, and baseline NIHSS score were independently associated with the early outcomes of patients with ACI.

Effect of bifurcation in the hemodynamic changes and rupture risk of small intracranial aneurysm

The role of bifurcations is prominent in the intracranial aneurysm (IA) evaluation, and there are many contradictions and complexities in the rupture risk of small IA. Therefore, in the present study, the effect of bifurcation on the manner of hemodynamic changes and the rupture risk of the small middle cerebral artery (MCA) aneurysm is investigated. 3D anatomical models of the MCAs of 21 healthy subjects, 19 patients/IA/bifurcation, and 19 patients/IA were generated, and the models were analyzed by the computational fluid dynamic (CFD) analysis. The presence of bifurcation in the pathway of the blood flow in the parent artery of healthy subjects has reduced the maximum velocity, flow rate, and wall shear stress (WSS) by 25.8%, 38.6%, and 11.1%, respectively. The bifurcation decreased the maximum velocity and flow rate in the neck and sac of the aneurysm by 1.65~2.1 times, respectively. It increased the maximum WSS, and phase lag between the WSS graph of healthy subjects and patients by 12.8%~13.9% and 10.2%~40.4%, respectively. The effect of bifurcation on the Womersley number change in the aneurysm was insignificant, and the blood flow was in the laminar flow condition in all samples. The results also showed bifurcation increased the phase lag between the flow rate and pressure gradient graphs up to approximately 1.5 times. The rupture prediction index for patients/IA/bifurcation and patients/IA was 62.1%(CV = 4.1) and 51.8%(CV = 4.4), respectively. Thus, in equal conditions, the presence of bifurcation increased the probability of the rupture of the aneurysm by 19.9%.

Unruptured intracranial aneurysm growth trajectory: occurrence and rate of enlargement in 520 longitudinally followed cases

OBJECTIVE

As imaging technology has improved, more unruptured intracranial aneurysms (UIAs) are detected incidentally. However, there is limited information regarding how UIAs change over time to provide stratified, patient-specific UIA follow-up management. The authors sought to enrich understanding of the natural history of UIAs and identify basic UIA growth trajectories, that is, the speed at which various UIAs increase in size.

METHODS

From January 2005 to December 2015, 382 patients diagnosed with UIAs (n = 520) were followed up at UCLA Medical Center through serial imaging. UIA characteristics and patient-specific variables were studied to identify risk factors associated with aneurysm growth and create a predicted aneurysm trajectory (PAT) model to differentiate aneurysm growth behavior.

RESULTS

The PAT model indicated that smoking and hypothyroidism had a large effect on the growth rate of large UIAs (≥ 7 mm), while UIAs < 7 mm were less influenced by smoking and hypothyroidism. Analysis of risk factors related to growth showed that initial size and multiplicity were significant factors related to aneurysm growth and were consistent across different definitions of growth. A 1.09-fold increase in risk of growth was found for every 1-mm increase in initial size (95% CI 1.04-1.15; p = 0.001). Aneurysms in patients with multiple aneurysms were 2.43-fold more likely to grow than those in patients with single aneurysms (95% CI 1.36-4.35; p = 0.003). The growth rate (speed) for large UIAs (≥ 7 mm; 0.085 mm/month) was significantly faster than that for UIAs < 3 mm (0.030 mm/month) and for males than for females (0.089 and 0.045 mm/month, respectively; p = 0.048).

CONCLUSIONS

Analyzing longitudinal UIA data as continuous data points can be useful to study the risk of growth and predict the aneurysm growth trajectory. Individual patient characteristics (demographics, behavior, medical history) may have a significant effect on the speed of UIA growth, and predictive models such as PAT may help optimize follow-up frequency for UIA management.

[Management of severe internal carotid stenosis with unruptured intracranial aneurysm]

OBJECTIVE

To investigate the safety and feasibility of endovascular treatment for severe internal carotid artery stenosis (≥70%) with unruptured intracranial aneurysms.

METHODS

We retrospectively reviewed 213 cases with severe stenosis or occlusion of internal carotid artery, and those patients had been treated at Peking University Third Hospital, between January 2012 and July 2015. In the study, 14 (6.6%) cases were coexistence with unruptured intracranial aneurysms. The medical records, imaging data, treatment and prognosis were analyzed.

RESULTS

There were 15 aneurysms (11 after the stenosis, 1 before the stenosis, and 3 in the other drainage basin) in those 14 patients with severe stenosis or occlusion of internal carotid artery. One of the 14 patients underwent carotid endarterectomy, and the 11 patients were successfully implanted with an internal carotid stent (residual stenosis 0-30%, mean 6.4%). Two patients with internal carotid artery stenosis remained untreated. One of them had complete occlusion of the initial segment of the internal carotid artery and was not possible to be treated, and the other patient refused to treat with internal carotid stenosis. The sizes of aneurysms were 1.0-7.0 mm, with an average of (2.8±1.5) mm. Three cases were treated with stenosis and aneurysms treated at the same time, and stent assisted coil embolization was performed in all the aneurysms, including 1 case that treated aneurysm before the stenosis. One patient refused surgical treatment of unruptured aneurysm, and no treatment was given to 10 patients who had small unruptured aneurysms (<5.0 mm). No perioperative complications were observed during the perioperative period. Three cases were lost with the follow-up, and the other 11 patients were followed up for 15-55 months, with a median of 37 months, and had good prognosis.

CONCLUSION

Our results suggest that patient coexistance with severe internal carotid stenosis and unruptured intracranial aneurysms should be treated individually according to the location and size of aneurysms. Moreover, the presence of a small intracranial aneurysm (<5.0 mm) does not seem to increase the risk of endovascular stenosis in patients with severe internal carotid stenosis.

[Management of severe internal carotid stenosis with unruptured intracranial aneurysm]

OBJECTIVE

To investigate the safety and feasibility of endovascular treatment for severe internal carotid artery stenosis (≥70%) with unruptured intracranial aneurysms.

METHODS

We retrospectively reviewed 213 cases with severe stenosis or occlusion of internal carotid artery, and those patients had been treated at Peking University Third Hospital, between January 2012 and July 2015. In the study, 14 (6.6%) cases were coexistence with unruptured intracranial aneurysms. The medical records, imaging data, treatment and prognosis were analyzed.

RESULTS

There were 15 aneurysms (11 after the stenosis, 1 before the stenosis, and 3 in the other drainage basin) in those 14 patients with severe stenosis or occlusion of internal carotid artery. One of the 14 patients underwent carotid endarterectomy, and the 11 patients were successfully implanted with an internal carotid stent (residual stenosis 0-30%, mean 6.4%). Two patients with internal carotid artery stenosis remained untreated. One of them had complete occlusion of the initial segment of the internal carotid artery and was not possible to be treated, and the other patient refused to treat with internal carotid stenosis. The sizes of aneurysms were 1.0-7.0 mm, with an average of (2.8±1.5) mm. Three cases were treated with stenosis and aneurysms treated at the same time, and stent assisted coil embolization was performed in all the aneurysms, including 1 case that treated aneurysm before the stenosis. One patient refused surgical treatment of unruptured aneurysm, and no treatment was given to 10 patients who had small unruptured aneurysms (<5.0 mm). No perioperative complications were observed during the perioperative period. Three cases were lost with the follow-up, and the other 11 patients were followed up for 15-55 months, with a median of 37 months, and had good prognosis.

CONCLUSION

Our results suggest that patient coexistance with severe internal carotid stenosis and unruptured intracranial aneurysms should be treated individually according to the location and size of aneurysms. Moreover, the presence of a small intracranial aneurysm (<5.0 mm) does not seem to increase the risk of endovascular stenosis in patients with severe internal carotid stenosis.

Characteristics of Intracranial Aneurysms According to Levels of Coronary Artery Calcium

Background and Purpose- Several vascular risk factors are known to be associated with the occurrence of intracranial aneurysms (IAs). Coronary artery calcium (CAC), which reflects the atherosclerotic burden of the coronary arteries, is a known predictor of cardiovascular events and stroke. We investigated the relationship between IA and CAC. Methods- We retrospectively enrolled Korean subjects at a single university hospital who had both brain magnetic resonance angiography and cardiac computed tomography as part of health examinations from January 2010 to July 2017. Subjects were categorized into 4 groups according to CAC score as assessed by cardiac computed tomography: zero (0), low (1-99), intermediate (100-399), or high (≥400). Then, the prevalence of IA in each CAC score group was assessed. We also performed subgroup analysis by age, sex, and location of IA. Results- A total of 4934 subjects (mean age, 54.1±9.8 years; %women, 42.2%) were included for analysis. IAs were detected in 258 subjects (5.23%). The prevalence of IA significantly increased as the CAC score increased (4.8%, 5.4%, 6.4%, and 11.1%, respectively; P for trend, 0.004). In subjects over the age of 50 years, this correlation was more prominent in women than in men (7.1% versus 3.7%, 8.8% versus 4.4%, 8.6% versus 6.3%, and 21.1% versus 10.0%, respectively). Subgroup analysis for the aneurysm location showed that nonbifurcation aneurysm was associated with a high CAC score but bifurcation aneurysm was not. Multivariate logistic regression showed high CAC score was an independent risk factor for the presence of IA compared with zero CAC score (adjusted odds ratio, 2.16; 95% CI, 1.18-3.95). Conclusions- A high CAC score was associated with the presence of IA. This relationship was more prominent in females and nonbifurcation aneurysms.

Association Between Unruptured Intracranial Aneurysms and Downstream Stroke

Background and Purpose- Case reports suggest that unruptured intracranial aneurysms may serve as a nidus for thrombus formation and downstream embolic stroke. However, few data exist to support an association between unruptured aneurysms and ischemic stroke. Methods- We conducted a within-subjects case-control study of acute ischemic stroke patients prospectively enrolled in the Cornell Acute Stroke Academic Registry who had magnetic resonance imaging of the brain and arterial imaging of the head within 14 days of admission. Reviewers blinded to the study hypothesis ascertained the presence of aneurysms from the neuroradiologist's clinical report of the arterial imaging findings. McNemar test for paired data was used to compare the prevalence of unruptured aneurysms ipsilateral versus contralateral to the side of anterior circulation infarcts. Aneurysms of the anterior communicating artery or in the posterior circulation were not counted in the analysis. Results- Among 2116 patients registered in the Cornell Acute Stroke Academic Registry during 2011 to 2016, 1541 met our inclusion criteria, of whom 176 (11.4%; 95% CI, 9.8-13.0%) had an intracranial aneurysm. The prevalence of aneurysms did not differ on the side ipsilateral versus contralateral to the infarction (risk ratio [RR], 1.2; 95% CI, 0.9-1.5). There was no significant association between aneurysms and ipsilateral stroke in secondary analyses of the 1244 patients with stroke in a single anterior circulation territory (RR, 1.2; 95% CI, 0.8-1.9), the 619 patients with cryptogenic stroke (RR, 1.4; 95% CI, 0.9-2.0), or the 485 patients with cryptogenic stroke in a single anterior circulation territory (RR, 1.7; 95% CI, 0.8-3.3). Results were unchanged when counting only aneurysms >3 mm (RR, 1.2; 95% CI, 0.8-1.9) or 5 mm in diameter (RR, 1.2; 95% CI, 0.9-1.5). Conclusions- Contrary to our hypothesis, we found no significant association between unruptured intracranial aneurysms and ipsilateral ischemic stroke.