Intracranial Saccular Aneurysms Research Articles

Verification of a simplified aneurysm dimensionless flow parameter to predict intracranial aneurysm rupture status.

Aneurysm number (An) is a novel prediction tool utilising parameters of pulsatility index (PI) and aneurysm geometry. An has been shown to have the potential to differentiate intracranial aneurysm (IA) rupture status. The objective of this study is to investigate the feasibility and accuracy of An for IA rupture status prediction using Australian based clinical data. A retrospective study was conducted across three tertiary referral hospitals between November 2017 and November 2020 and all saccular IAs with known rupture status were included. Two sets of An values were calculated based on two sets of PI values previously reported in the literature. Five hundred and four IA cases were included in this study. The results demonstrated no significant difference between ruptured and unruptured status when using An ≥ 1 as the discriminator. Further analysis showed no strong correlation between An and IA subtypes. The area under the curve (AUC) indicated poor performance in predicting rupture status (AUC1=0.55 and AUC2=0.56). This study does not support An ≥ 1 as a reliable parameter to predict the rupture status of IAs based on a retrospective cohort. Although the concept of An is supported by hemodynamic aneurysm theory, further research is needed before it can be applied in the clinical setting. This study demonstrates that the novel prediction tool, An, proposed in 2020 is not reliable and that further research of this hemodynamic model is needed before it can be incorporated into the prediction of intracranial aneurysm rupture status.

Neurovascular Imaging with Ultra-High-Resolution Photon-Counting CT: Preliminary Findings on Image Quality Evaluation.

The first-generation photon-counting detector (PCD) CT was recently introduced into clinical practice and represents a promising innovation in high-resolution CT imaging. The purpose of this study was to assess the image quality of ultra-high-resolution (UHR) PCD-CT compared with energy-integrating detector (EID)-CT, and to explore different reconstruction kernel sharpness levels for the evaluation of intracranial aneurysms. Ten patients with intracranial saccular aneurysms, who had previously undergone conventional EID-CT, were prospectively enrolled. CT angiograms were acquired on a clinical dual-source PCD-CT in UHR mode, and reconstructed with four vascular kernels (Bv36, Bv40, Bv44, Bv48). Quantitative and qualitative image quality parameters of the intracranial arteries were evaluated. For the quantitative analysis (image noise, SNR, CNR), regions of interest were manually placed at standard anatomical intracranial and extracranial locations by one author. In addition, vessel border sharpness was evaluated quantitatively. For the qualitative analysis, three blinded neuroradiologists rated PCD-CT and EID-CT image quality for the evaluation of the intracranial vessels (i.e., the aneurysms and nine standard vascular branching locations) on a 5-point Likert-type scale. Additionally, readers independently selected their preferred kernel among the four kernels evaluated on PCD-CT. In terms of quantitative image quality, Bv48, the sharpest kernel, yielded increased image noise, and decreased SNR and CNR parameters compared to Bv36, the smoothest kernel. Compared to EID-CT, the Bv48 kernel offered better quantitative image quality for the evaluation of small intracranial vessels (p < .001). Image quality ratings of the Bv48 were superior to those of the EIDCT, and not significantly different from ratings of the B44 reconstruction kernel. When comparing side-by-side all four PCD-CT reconstruction kernels, readers selected the B48 kernel as the best to visualize the aneurysms in 80% of cases. UHR PCD-CT provides improved image quality for neurovascular imaging. Although the less sharp kernels provided superior SNR and CNR, the sharpest kernels delivered the best subjective image quality on PCD-CT for the evaluation of intracranial aneurysms.CNR ＝ Contrast-to-Noise Ratio; EID-CT ＝ Energy-Integrating Detector CT; PCD-CT ＝ Photon-Counting Detector CT; QIR ＝ Quantum Iterative Reconstruction; UHR ＝ Ultra-High-Resolution.

The rupture risk of intracranial saccular aneurysm: a case-control study based on a three-dimensional computed tomography angiography model.

Assessing the risk of rupture in intracranial aneurysms is crucial. Advancements in medical imaging now allow for three-dimensional (3D) assessments of aneurysms, providing a more detailed understanding of their morphology and associated risks. This study aimed to compare the 3D morphological parameters of ruptured and unruptured intracranial saccular aneurysms (ISAs) using computed tomography angiography (CTA) and to analyze risk factors linked to ISA rupture. This retrospective case-control study included patients diagnosed with ISAs via CTA, for which data were sourced from both the Emergency Department and Inpatient Unit in The First Affiliated Hospital of Jinan University. The patients were categorized into rupture and unrupture groups. We used 3D-Slicer (version 5.2.2, Slicer Community) to construct morphological models of the ISAs and their parent arteries. These models facilitated assessments of intracranial aneurysmal volume (IAV), aneurysmal surface area (ASA), and maximum sectional area (MSA). Differences in 3D morphological parameters between ruptured and unruptured ISAs were then analyzed. For statistical analysis, we first performed single factor analysis on the data, constructed a receiver operating characteristic (ROC) curve one by one with statistically significant parameters, and screened out ROC curves that met the sample requirements. Second, we performed multiparameter logistic regression analysis to construct a ROC curve model and analyzed its predictive performance. The analysis encompassed 97 patients comprising 97 ISAs diagnosed from March 2016 to March 2022. Significant differences in morphological parameters were observed between the rupture and unrupture groups (P<0.05), including IAV, ASA, MSA, IAV/diameter (IAV/D), IAV/neck width (IAV/N), MSA/diameter (MSA/D), MSA/neck width (MSA/N), ASA/neck width (ASA/N), and ASA/MSA. It was found that the IAV, ASA, and MSA values of the rupture group were larger than those of the unrupture group. Meanwhile, the IAV/D, IAV/N, MSA/D, MSA/N, and ASA/N values were larger in the rupture group, while ASA/MSA and ASA/IAV were smaller. This study underscores the significance of specific morphological indicators, such as ASA/N and ASA/MSA, in predicting the rupture risk of ISAs. The IAV, MSA, and ASA parameters, especially in relation to diameter and neck width, provide crucial insights into the rupture potential of ISAs.

Nomogram-based geometric and hemodynamic parameters for predicting the growth of small untreated intracranial aneurysms.

Previous studies have shown that the growth status of intracranial aneurysms (IAs) predisposes to rupture. This study aimed to construct a nomogram for predicting the growth of small IAs based on geometric and hemodynamic parameters. We retrospectively collected the baseline and follow-up angiographic images (CTA/ MRA) of 96 small untreated saccular IAs, created patient-specific vascular models and performed computational fluid dynamics (CFD) simulations. Geometric and hemodynamic parameters were calculated. A stepwise Cox proportional hazards regression analysis was employed to construct a nomogram. IAs were stratified into low-, intermediate-, and high-risk groups based on the total points from the nomogram. Receiver operating characteristic (ROC) analysis, calibration curves, decision curve analysis (DCA) and Kaplan-Meier curves were evaluated for internal validation. In total, 30 untreated saccular IAs were grown (31.3%; 95%CI 21.8%-40.7%). The PHASES, ELAPSS, and UIATS performed poorly in distinguishing growth status. Hypertension (hazard ratio [HR] 4.26, 95%CI 1.61-11.28; P = 0.004), nonsphericity index (95%CI 4.10-25.26; P = 0.003), max relative residence time (HR 1.01, 95%CI 1.00-1.01; P = 0.032) were independently related to the growth status. A nomogram was constructed with the above predictors and achieved a satisfactory prediction in the validation cohort. The log-rank test showed significant discrimination among the Kaplan-Meier curves of different risk groups in the training and validation cohorts. A nomogram consisting of geometric and hemodynamic parameters presented an accurate prediction for the growth status of small IAs and achieved risk stratification. It showed higher predictive efficacy than the assessment tools.

Flow diverters treatment planning of small- and medium-sized intracranial saccular aneurysms on the internal carotid artery via constraint-based virtual deployment.

The internal carotid artery (ICA) is a region with a high incidence for small- and medium-sized saccular aneurysms. However, the treatment relies heavily on the surgeon's experience to achieve optimal outcome. Although the finite element method (FEM) and computational fluid dynamics can predict the postoperative outcomes, due to the computational complexity of traditional methods, there is an urgent need for investigating the fast but versatile approaches related to numerical simulations of flow diverters (FDs) deployment coupled with the hemodynamic analysis to determine the treatment plan. We collected the preoperative and postoperative data from 34 patients (29 females, 5 males; mean age 55.74 ± 9.98 years) who were treated with a single flow diverter for small- to medium-sized intracranial saccular aneurysms on the ICA. The constraint-based virtual deployment (CVD) method is proposed to simulate the FDs expanding outward along the vessel centerline while be constrained by the inner wall of the vessel. The results indicate that there were no significant differences in the reduction rates of wall shear stress and aneurysms neck velocity between the FEM and methods. However, the solution time of CVD was greatly reduced by 98%. In the typical location of small- and medium-sized saccular aneurysms, namely the ICA, our virtual FDs deployment simulation effectively balances the computational accuracy and efficiency. Combined with hemodynamics analysis, our method can accurately represent the blood flow changes within the lesion region to assist surgeons in clinical decision-making.

Compare deep learning model and conventional logistic regression model for the identification of unstable saccular intracranial aneurysms in computed tomography angiography.

It is crucial to distinguish unstable from stable intracranial aneurysms (IAs) as early as possible to derive optimal clinical decision-making for further treatment or follow-up. The aim of this study was to investigate the value of a deep learning model (DLM) in identifying unstable IAs from computed tomography angiography (CTA) images and to compare its discriminatory ability with that of a conventional logistic regression model (LRM). From August 2011 to May 2021, a total of 1,049 patients with 681 unstable IAs and 556 stable IAs were retrospectively analyzed. IAs were randomly divided into training (64%), internal validation (16%), and test sets (20%). Convolutional neural network (CNN) analysis and conventional logistic regression (LR) were used to predict which IAs were unstable. The area under the curve (AUC), sensitivity, specificity and accuracy were calculated to evaluate the discriminating ability of the models. One hundred and ninety-seven patients with 229 IAs from Banan Hospital were used for external validation sets. The conventional LRM showed 11 unstable risk factors, including clinical and IA characteristics. The LRM had an AUC of 0.963 [95% confidence interval (CI): 0.941-0.986], a sensitivity, specificity and accuracy on the external validation set of 0.922, 0.906, and 0.913, respectively, in predicting unstable IAs. In predicting unstable IAs, the DLM had an AUC of 0.771 (95% CI: 0.582-0.960), a sensitivity, specificity and accuracy on the external validation set of 0.694, 0.929, and 0.782, respectively. The CNN-based DLM applied to CTA images did not outperform the conventional LRM in predicting unstable IAs. The patient clinical and IA morphological parameters remain critical factors for ensuring IA stability. Further studies are needed to enhance the diagnostic accuracy.

Endovascular Coiling of Ruptured Tiny Saccular Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BackgroundThe safety and efficacy of endovascular coiling of ruptured tiny saccular intracranial aneurysms (IAs) (≤ 3mm) remains unknown. MethodsA comprehensive search of PubMed, Embase, Web of Science, and Scorpus databases up to November 15, 2023 was performed. Pooled prevalence was calculated for occlusion rates, recanalization, retreatment, long-term favorable outcome, and procedure-related complications and mortality. Pooled odds ratios were calculated to compare these outcomes between coiling and stent-assisted coiling (SAC). Results42 studies with 2,174 ruptured tiny saccular IAs treated with coiling were included. The follow-up complete aneurysm occlusion rate was 83.9% (95% CI: 77.2–88.9%). The rates of recanalization and retreatment were 7.7% (95% CI: 5.7–10.2%) and 5.8% (95% CI: 4.5–7.5%). The range of median Hunt and Hess grades was 1.4–2.9 and the favorable outcome rate was 85.6% (95% CI: 81.1–89.2%). The rates of thromboembolism, intraprocedural rupture, and mortality were 4.6% (95% CI: 3.6–5.8%), 5.4% (95% CI: 4.1–7.0%), and 5.6% (95% CI: 4.4–7.2%), respectively. Comparison of coiling and SAC revealed no significant difference, except for a higher likelihood of follow-up complete aneurysm occlusion in SAC (odds ratio [OR] 0.37, 95% CI: 0.17–0.80) and recanalization in the coiling (OR, 3.21 [95% CI, 1.37–7.51]). ConclusionsOur meta-analysis demonstrates that coiling for ruptured tiny saccular IA is a feasible, effective, and safe approach that is associated with favorable clinical outcomes in both the short and long term for patients with mild to moderate Hunt and Hess grades.

Optimizing Patient Care: A Multicentric Study on the Clinical Impact of Sim&Size™ Simulation Software in Intracranial Aneurysm Treatment With Pipeline Embolization Devices

Background and PurposeTo determine the clinical effects (stent size, and number of stents used) of the Sim&SizeTM simulation software on the endovascular treatment of unruptured saccular intracranial aneurysms with Pipeline Embolization Devices (PED). Materials and MethodsThis study is a retrospective analytical multicenter study of patients treated with PED (Flex and Flex with SHIELD) for intracranial aneurysm in XXXX and XXXX. ResultsThe study included 253 patients, of which 75 were treated in Colombia and 178 were treated in France. The majority of patients were women (83.8%), with a median age of 57.48 years, and had large vessel location (88.1%), with most aneurysms located in the ICA paraclinoid segment (56.8%). Patients in the group with Sim&SizeTM simulation had shorter stents than those without simulation (15.62 mm vs. 17.36 mm, p-value= 0.001). Also, a lower proportion of these patients required more than one stent (1.4% vs. 7.3%, p-value=0.022). There were 7 complications reported in the group that used the Sim&SizeTM simulation software, compared to 9 complications in the group that did not use the software. ConclusionsUsing Sim&SizeTM simulation software for endovascular treatment of patients with intracranial aneurysms using PED reduces the stent length and decreasing the number of devices needed per treatment.

Unveiling rupture risk and clinical outcomes in midline aneurysms: A matched cohort analysis investigating the impact of localization within the anterior or posterior circulation.

Intracranial aneurysms (IAs) located in the anterior and posterior circulations of the Circle of Willis present differential rupture risks. This study aimed to compare the rupture risk and clinical outcomes of anterior communicating artery aneurysms (AcomA) and basilar tip aneurysms (BAs); two IA types located along the midline within the Circle of Willis. We retrospectively collected data from 1026 patients presenting with saccular IAs. Only AcomA and BAs with a 3D angiography were included. Out of 186 included IAs, a cohort of 32 BAs was matched with AcomA based on the patients' pre-existing conditions and morphological parameters of IAs. Clinical outcomes, including rupture risk, hydrocephalus development, vasospasm incidence, and patients' outcome, were compared. The analysis revealed no significant difference in rupture risk, development of hydrocephalus, need for ventricular drainage, or vasospasm incidence between the matched AcomA and BA cohorts. Furthermore, the clinical outcomes post-rupture did not significantly differ between the two groups, except for a higher Fisher Grade associated with BAs. Once accounting for morphological and patient factors, the rupture risk between AcomA and BAs is comparable. These findings underscore the importance of tailored management strategies for specific IA types and suggest that further investigations should focus on the role of individual patient and aneurysm characteristics in IA rupture risk and clinical outcomes.

Low and Borderline Ankle-Brachial Index Is Associated With Intracranial Aneurysms: A Retrospective Cohort Study.

A low ankle-brachial index (ABI) has been linked to systemic inflammation and an elevated risk of cardiovascular events, most notably myocardial infarction and stroke. Intracranial aneurysms (IAs) share similar risk factors with other cardiovascular diseases. However, the association between low ABI and IAs has not been sufficiently investigated. Our objective was to investigate the potential connection between ABI values and the prevalence of unruptured IAs. This retrospective cohort study reviewed 2751 patients who had ABI measurements at a public tertiary hospital from January 2011 to December 2013. Patients with available cerebrovascular imaging or a diagnosis of ruptured IA were included in the study (n = 776) to examine the association between ABI and saccular IAs. The patients were classified into 4 groups: low ABI (≤0.9, n = 464), borderline ABI (0.91-0.99; n = 47), high ABI (>1.4, n = 57), and normal ABI (1.00-1.40; n = 208). The prevalence of IAs was 20.3% (18.1% unruptured IAs) in the low ABI group, 14.9% (12.8% unruptured IAs) in the borderline ABI group, 7.0% (5.3% unruptured IAs) in the high ABI group, and 2.4% (1.9% unruptured IAs) in the normal ABI group (P < .001). There were no significant differences in the prevalence of ruptured IAs between the ABI groups (P = .277). Sex- and age-adjusted multinomial regression, including clinically relevant variables, revealed that low ABI (odds ratio [OR], 13.02; 95% CI, 4.01-42.24), borderline ABI (OR, 8.68; 95% CI, 2.05-36.69), and smoking history (OR, 2.01; 95% CI, 1.07-3.77) were associated with unruptured IAs. The prevalence of unruptured IAs was 9-fold higher in the low ABI group and nearly 7-fold higher in the borderline ABI group when compared with the normal ABI group. ABI measurements could be clinically relevant for identifying individuals at higher risk of IAs and may help guide screening and preventive strategies.

Systematic Review and Meta‐Analysis of Endovascular Therapy Effectiveness for Unruptured Saccular Intracranial Aneurysms

Background Currently, endovascular treatment of intracranial aneurysms is limited by low complete occlusion rates. The advent of novel endovascular technology has expanded the applicability of endovascular therapies; however, the superiority of novel embolic devices over the traditional Guglielmi detachable coils is still debated. We performed a systematic review of literature that reported the Raymond–Roy occlusion classification (RROC) rates of modern endovascular devices to determine their immediate and follow‐up occlusion effectivenesses for the treatment of unruptured saccular intracranial aneurysms. Methods A search was conducted using electronic databases (PUBMED, Cochrane, ClinicalTrials.gov, and Web of Science). We retrieved studies published between 2000 and 2022, reporting immediate and follow‐up RROC rates of subjects treated with different endovascular intracranial aneurysm therapies. We extracted demographic information of the treated patients and their reported angiographic RROC rates. Results A total of 80 studies from 15 countries were included for data extraction. The RROC rates determined from angiogram were obtained for 21 331 patients (72.5% women, pooled mean age: 58.2 [95% CI]: 56.8–59.6), harboring 22 791 aneurysms. The most frequent aneurysm locations were the internal carotid artery (46.4%, 95% CI: 41.9%–50.9%), the anterior communicating artery (26.4%, 95% CI: 22.5%–30.8%), the middle cerebral artery (24.5%, 95% CI: 19.2%–30.8%), and the basilar tip (14.4%, 95% CI: 11.3%–18.3%). The complete occlusion probability (RROC‐I) was analyzed for Guglielmi detachable coils, the Woven EndoBridge, and flow diverters. The RROC‐I rate was the highest in balloon‐assisted coiling (73.9%, 95% CI: 65.0%–81.2%) and the lowest in the Woven EndoBridge (27.8%, 95% CI: 13.2%–49.2%). The follow‐up RROC‐I probability was homogenous in all analyzed devices. Conclusion We observed that the coil‐based endovascular therapy provides acceptable rates of complete occlusion, and these rates are improved in balloon‐assisted coils. Out of the analyzed devices, the Woven EndoBridge exhibited the shortest time to achieve &gt;90% probability of follow‐up complete occlusion (∼18 months). Overall, the Guglielmi detachable coils remain the gold standard for endovascular treatment of unruptured saccular aneurysms.

Fusiform versus Saccular Intracranial Aneurysms-Hemodynamic Evaluation of the Pre-Aneurysmal, Pathological, and Post-Interventional State.

Minimally-invasive therapies are well-established treatment methods for saccular intracranial aneurysms (SIAs). Knowledge concerning fusiform IAs (FIAs) is low, due to their wide and alternating lumen and their infrequent occurrence. However, FIAs carry risks like ischemia and thus require further in-depth investigation. Six patient-specific IAs, comprising three position-identical FIAs and SIAs, with the FIAs showing a non-typical FIA shape, were compared, respectively. For each model, a healthy counterpart and a treated version with a flow diverting stent were created. Eighteen time-dependent simulations were performed to analyze morphological and hemodynamic parameters focusing on the treatment effect (TE). The stent expansion is higher for FIAs than SIAs. For FIAs, the reduction in vorticity is higher (Δ35-75% case 2/3) and the reduction in the oscillatory velocity index is lower (Δ15-68% case 2/3). Velocity is reduced equally for FIAs and SIAs with a TE of 37-60% in FIAs and of 41-72% in SIAs. Time-averaged wall shear stress (TAWSS) is less reduced within FIAs than SIAs (Δ30-105%). Within this study, the positive TE of FDS deployed in FIAs is shown and a similarity in parameters found due to the non-typical FIA shape. Despite the higher stent expansion, velocity and vorticity are equally reduced compared to identically located SIAs.

Aneurysm Wall Contrast on Magnetic Resonance Imaging: A New Predictor of Rupture of Saccular Intracranial Aneurysms

Background. Recent studies suggest that accumulation of contrast agent in the aneurysm’s wall may predict a high risk of aneurysm growth or rupture.Objective. To compare the enhancement of the aneurysm wall with other characteristics that affect at the risk of rupture.Materials and Methods. The study included 95 patients with 132 previously identified saccular aneurysms, who underwent magnetic resonance imaging (MRI) according to a specialized protocol using 3.0 Tesla MRI scanner. The presence or absence of aneurysm’s wall enhancement compared with the following characteristics: gender and age of the patient, the size and shape of the aneurysm, the presence of arterial hypertension, and the PHASES score.Results. Accumulation of contrast agent by the aneurysm’s wall was associated with the aneurysm dome size (p &lt; 0,001, Sp = 78,1 %, Se = 72,1 %) and PHASES score (p &lt; 0,001, Sp = 64,1 %, Se =57,1 %). No relationship between age, gender, arterial hypertension, shape, and aneurysm location and contrast enhancement was found (p &gt; 0,05).Conclusion. Contrast enhancement of the aneurysm wall on MRI can be considered an additional risk marker of its rupture.

Neutrophil-to-lymphocyte ratio associated with symptomatic saccular unruptured intracranial aneurysm

Background and purposeWhether symptomatic unruptured intracranial aneurysms (UIAs) lead to change in circulating inflammation remains unclear. This study aims to evaluate the role of hematological inflammatory indicators in predicting symptomatic UIA.MethodsAdult patients diagnosed with saccular intracranial aneurysm from March 2019 to September 2023 were recruited retrospectively. Clinical and laboratory data, including the white blood cells (WBC), neutral counts (NEUT), lymphocyte counts (LYM), and monocyte counts (MONO) of each patient, were collected. The neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR) were calculated as NLR = NEUT/LYM, LMR = LYM/MONO, SII = PLT*NEUT/LYM. The hematological inflammatory indicators were compared in symptomatic saccular and asymptomatic UIA patients. Multivariable logistic regression analyses were performed to explore the factors predicting symptomatic UIA.ResultsOne hundred and fifty UIA patients with a mean age of 58.5 ± 12.4 were included, of which 68% were females. The NLR and LMR were significantly associated with symptomatic UIA, and the association remained in small UIAs (< 7 mm). The multiple logistic regression analysis showed that NLR was independently associated with symptomatic UIA. On ROC curve analysis, the optimal cutoff value of NLR to differentiate symptomatic from asymptomatic was 2.38. In addition, LMR was significantly associated with symptomatic UIA smaller than 7 mm.ConclusionThere was a significant correlation between NLR and symptomatic UIA. The NLR was independently associated with symptomatic UIA.

Predicting incomplete occlusion of intracranial aneurysms treated with flow diverters using machine learning models.

Intracranial saccular aneurysms are vascular malformations responsible for 80% of nontraumatic brain hemorrhage. Recently, flow diverters have been used as a less invasive therapeutic alternative for surgery. However, they fail to achieve complete occlusion after 6 months in 25% of cases. In this study, the authors built a tool, using machine learning (ML), to predict the aneurysm occlusion outcome 6 months after treatment with flow diverters. A total of 667 aneurysms in 616 patients treated with the Pipeline embolization device at a tertiary referral center between January 2011 and December 2017 were included. To build the predictive tool, two experiments were conducted. In the first experiment, six ML algorithms (support vector machine [SVM], decision tree, random forest [RF], k-nearest neighbor, XGBoost, and CatBoost) were trained using 26 features related to patient risk factors and aneurysm morphological characteristics, and the results were compared with logistic regression (LR) modeling. In the second experiment, the models were trained using the top 10 features extracted by Shapley additive explanation (SHAP) analysis performed on the RF model. The results showed that the authors' tool can better predict the occlusion outcome than LR (accuracy of 89% for the SVM model vs 62% for the LR model), even when trained using a subset of the features (83% accuracy). SHAP analysis revealed that age, hypertension, smoking status, branch vessel involvement, aneurysm neck, and larger diameter dimensions were among the most important features contributing to accurate predictions. In this study, an ML-based tool was developed that successfully predicts outcome in intracranial aneurysms treated with flow diversion, thus helping neurosurgeons to practice a more refined approach and patient-tailored medicine.

Abstract 18311: Low and Borderline Ankle Brachial Index Are Associated With Intracranial Aneurysms - A Retrospective Cohort Study

Background: A low ankle-brachial index (ABI) is associated with a higher risk of cardiovascular diseases, stroke, and systemic inflammation. Intracranial aneurysms (IAs) share similar risk factors with other cardiovascular diseases. However, there is a lack of studies that investigate the association between low ABI and IAs. Aims: To study whether low, borderline, or high ABI is associated with an increased risk of IAs compared to a normal ABI. Methods: We conducted a retrospective review of all patients (n=2751) who had ABI measurements at our tertiary hospital between 2011 and 2013. Patients with available cerebrovascular imaging or a diagnosis of a ruptured IA were included in the study (n=776) to examine the association between ABI and saccular IAs. The patients were classified into four groups as follows: low ABI (≤0.9, n=464), borderline ABI (0.91-0.99, n=47), high ABI (&gt;1.4, n=56), and normal ABI (1.00-1.40, n=209). Results: The prevalence of IAs was 20.3% (18.1% unruptured IAs) in the low ABI group, 14.9% (12.8% unruptured IAs) in the borderline ABI group, 7.0% (5.3% unruptured IAs) in the high ABI group, and 2.4% (1.9% unruptured IAs) in the normal ABI group (p &lt;0.001). In the multinomial regression, which included clinically relevant variables, low ABI (odds ratio [OR], 11.3; 95% confidence interval [CI], 4.1-31.5; p &lt; 0.001) and borderline ABI (OR, 7.1; 95% CI, 1.9-26.6; p &lt;0.001) were the only variables significantly associated with unruptured IAs. Conclusions: Patients with low ABI and borderline ABI had a higher prevalence of IAs compared to patients with a normal ABI. The prevalence of IAs was almost 9-fold higher in the low ABI group and nearly 7-fold higher in the borderline ABI group when compared to the normal ABI group.

Abstract 170: Flow Diversion for Distal Aneurysms of the Posterior Circulation: A Multicenter Retrospective Study

Introduction Flow diversion (FD) has emerged as an effective treatment option for intracranial aneurysms (IAs). However, there is limited evidence regarding its safety and efficacy specifically for distal aneurysms of the posterior circulation including posterior inferior cerebellar artery (PICA), anterior inferior cerebellar artery (AICA), superior cerebellar artery (SCA), and the P2 and P3 segment of the posterior cerebral artery (PCA). This study aimed to investigate the outcomes of FD for these aneurysms. Methods A retrospective analysis of a multicentric observational registry was performed between 2014 and 2022. Patients harboring distal aneurysms of the posterior circulation including the PICA, AICA, SCA, and PCA P2‐3 treated with FD were included. Aneurysms characteristics and outcomes were calculated for the total series and a comparison was performed between fusiform/dissecting versus saccular aneurysms. The primary outcome was complete occlusion at last imaging follow up which was defined as per the Raymond Roy occlusion scale. Additional outcomes included the retreatment rate, and thromboembolic and hemorrhagic complications Results Overall, 36 patients with 36 aneurysms were treated with FD with a median age in years of 60.0 (interquartile range [IQR]: 52.8‐65.3 years). Of those, 13 were fusiform/dissecting while 23 were saccular IAs. Complete occlusion was achieved in 78.1% for all IAs at a median follow‐up of 14.0 months (IQR: 9.3‐48.6 months). There was no significant difference in rates of complete occlusion between fusiform/dissecting (91.7%) and saccular aneurysms (70%, p=0.151). Thromboembolic and hemorrhagic complications were observed in four cases (11.1%), and retreatment was required for four IAs (11.4%). There was no significant difference in rates of thromboembolic and hemorrhagic complications, or retreatment between fusiform/dissecting and saccular IAs Conclusion This study suggests the safety and efficacy of FD for distal aneurysms of the posterior circulation. Further larger‐scale studies are warranted to confirm these findings and to explore the long‐term safety and efficacy of FD in this specific aneurysm population.

Abstract 174: Treatment of Unruptured Saccular Aneurysms with PED: A Systematic Review and Meta‐Analysis of Long‐Term Outcomes

Introduction The Pipeline Embolization Device (PED) is commonly used for intracranial aneurysm treatment. While its effectiveness for certain types of aneurysms is well‐established, its efficacy for saccular aneurysms remains debatable. This review and meta‐analysis aimed to assess the long‐term outcomes of PED treatment for unruptured intracranial aneurysms (UIA). Methods A systematic review and meta‐analysis were conducted following PRISMA guidelines. Studies with at least one year of follow‐up after PED treatment for saccular aneurysms were included. The primary endpoint was angiographic complete aneurysm occlusion at long‐term (≥ 12 mo.) follow‐up. Secondary outcomes included long‐term complications. We conducted a meta‐regression analysis to explore the potential sources of heterogeneity across studies. Results Eleven studies on 594 patients with 726 aneurysms were included, of which 5% were previously treated. The mean age was 55.7 years, and 78.3% were women. The mean aneurysm size was 7.72 mm, 8.95% were treated with more than one device, and 2.9% had adjunct coiling. The long‐term complete occlusion rate was 81% (CI 95%: 72% to 88%, p&lt;0.01). Regarding long‐term complications, the rate of symptomatic ischemic stroke was 1% (CI 95%: 0% to 4%, p=0.07), the rate of delayed rupture was 1% (95%, CI 0% to 3%, p=0.02), and the rate of intracranial hemorrhage was 3% (CI 95%: 1% to 6%, p=0.81). The meta‐regression analysis revealed a decreasing trend per year for aneurysmal occlusion, ischemic stroke rate, and aneurysmal rupture rate over time and an increasing trend for ICH over time. Conclusion PED demonstrates high long‐term occlusion and low complication rates, suggesting it is a safe and effective treatment option for unruptured intracranial saccular aneurysms. However, studies with greater than 5‐10 years of follow‐up are needed to evaluate the clinical and radiographical outcomes of incompletely occluded aneurysms Additionally, as newer devices exhibit reduced thrombogenic profiles and ICH rates increase over time, reevaluation of antiplatelet therapy's role, including dosage and DAPT, is warranted.

Prevalence of pre-eclampsia in 265 patients with an intracranial aneurysm, 393 female relatives versus a control cohort: Acase-control study.

There is emerging evidence on the connection between pre-eclampsia and saccular intracranial aneurysms (sIAs). Our aim was to study the prevalence of pre-eclampsia in sIA patients, their female relatives, and matched controls, and to examine familial sIA disease and familial pre-eclampsia in sIA patients' families. We included all female sIA patients in the Kuopio Intracranial Aneurysm Patient and Family Database from 1995 to 2018. First, we identified the sIA patients, their female relatives, and matched population controls with the first birth in 1987 or later and studied the prevalence of pre-eclampsia. Second, all female sIA patients and all female relatives were analyzed for familial sIA disease and familial pre-eclampsia. Using the Finnish nationwide health registries, we obtained data on drug purchases, hospital diagnoses, and causes of death. In total, 265 sIA patients, 57 daughters, 167 sisters, 169 nieces, and 546 matched controls had the first birth in 1987 or later. Among them, 29 (11%) sIA patients, 5 (9%) daughters, 10 (6%) sisters, 10 (6%) nieces, and 32 (6%) controls had pre-eclampsia. Of all the 1895 female sIA patients and 12,141 female relatives, 68 sIA patients and 375 relatives had pre-eclampsia, including 32 families with familial pre-eclampsia. Pre-eclampsia was significantly more common in the sIA patients than in their matched controls. Familial sIA disease and familial pre-eclampsia co-occurred in seven families. Further studies of the mechanisms by which pre-eclampsia could affect the walls of brain arteries and increase the rupture risk in sIA disease are indicated.

Early clinical experience with the new generation Pipeline Vantage flow diverter in the treatment of unruptured saccular aneurysms using short-term dual antiplatelet therapy.

The Pipeline Vantage flow diverter with Shield technology (PV) used in this study is a 4th-generation flow diverter (FD) designed to reduce thrombogenicity, promote endothelialization of the implant and increase efficiency in achieving aneurysm closure. In this study, we report the aneurysm occlusion rate, complication rate and clinical outcome with short-term dual antiplatelet therapy (DAPT) in the treatment of unruptured intracranial saccular aneurysms using the PV. We retrospectively identified patients treated between September 2021 and January 2023 with the PV and subsequently underwent short-term DAPT for 3 months. Patient and aneurysm characteristics, peri- and post-procedural complications, clinical outcomes and the grade of aneurysm occlusion were documented. Thirty patients with 32 aneurysms were treated. Successful FD implantation was achieved in all cases (100%). No periprocedural complications were documented. The overall symptomatic complication rate was 10% and the neurologic, treatment-related symptomatic complication rate was 6.6%. Only one symptomatic complication (3.3%) was device-related. Permanent clinical deterioration occurred in 2/30 patients (6.6%), leading to deterioration of the mRS within the first 3 months after treatment. No mortality was documented. The rate of complete aneurysm occlusion after 3 months and after a mean imaging follow-up of 9.9 months was 65.6% and 75%, respectively. Implantation of the PV for the treatment of saccular intracranial aneurysms achieves a good aneurysm occlusion rate with a low rate of complications. In addition, the use of short-term DAPT after PV implantation appears to be safe.