pEGASUS-HPC Stent Pusher-Assisted Catheterization (PAC) Technique in Y-Stent-Assisted Coiling of Unruptured Wide-Necked Cerebral Aneurysms: A Multicenter Retrospective Study

pEGASUS-HPC Stent Pusher-Assisted Catheterization (PAC) Technique in Y-Stent-Assisted Coiling of Unruptured Wide-Necked Cerebral Aneurysms: A Multicenter Retrospective Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article pEGASUS-HPC Stent Pusher-Assisted Catheterization (PAC) Technique in Y-Stent-Assisted Coiling of Unruptured Wide-Necked Cerebral Aneurysms: A Multicenter Retrospective Study Mohammad Almohammad, Bayan Alhaj Moustafa, Ali Khanafer, Mete Dadak, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7542254/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 15 Nov, 2025 Read the published version in Neuroradiology → Version 1 posted You are reading this latest preprint version Abstract Objectives: To evaluate the safety and efficacy of the pusher-assisted catheterization (PAC) technique using the pEGASUS-HPC stent pusher instead of a microwire for accessing unruptured wide-necked cerebral aneurysms during Y-stent-assisted coiling. Methods: In this multicenter retrospective study (July 2021– June 2025), 48 unruptured wide-necked cerebral aneurysms underwent Y-stent-assisted coiling using pEGASUS HPC stents. Based on the catheterization technique, cases were assigned to either the microwire-assisted catheterization (MAC, n=23) or the stent pusher-assisted catheterization (PAC, n=25) group. Clinical and procedural data were analyzed to compare safety and efficacy, focusing on success rates, required catheterization time, complications, and adverse events. Results: The cohort had a mean age of 62.6 ± 9.8 years, with 64.3% of patients being female. In the MAC group, aneurysm catheterization was successful in all 23 cases (100%), with a mean catheterization time of 5.31 ± 1.2 minutes. In contrast, the PAC group achieved successful catheterization in 88% of cases (22/25), with a markedly reduced mean catheterization time of 0.82 ± 0.27 minutes—approximately 6.5 times faster than the conventional MAC technique (p < 0.001). Importantly, no procedure-related complications, such as perforations or dissections, were observed in either group. Conclusion: The PAC technique using the pEGASUS-HPC stent appears to be a safe and time-efficient alternative to microwire-assisted catheterization in Y-stent-assisted coiling of unruptured wide-necked cerebral aneurysms. It significantly reduces catheterization time without increasing complication rates. Further studies are needed to confirm these preliminary findings. Stent pusher pEGASUS HPC coiling catheterization Figures Figure 1 Figure 2 INTRODUCTION In stent-assisted coiling (SAC), two commonly used techniques exist for positioning the tip of the coiling microcatheter within the aneurysm sac, depending on the procedural strategy. The first, known as the jailing technique, involves placing the coiling microcatheter into the aneurysm sac before deploying a stent via a second microcatheter in the parent vessel, thereby trapping (or "jailing") the coiling catheter between the stent and the vessel wall. The second approach entails first deploying the stent, followed by navigating the coiling microcatheter through the stent struts into the aneurysm sac 1 , 2 . In the present study, the latter technique was applied in all cases. Among the various advanced SAC techniques, Y-stenting has gained particular relevance for bifurcation aneurysms, where conventional strategies often fall short. By creating a Y-shaped scaffold at the vessel bifurcation, this approach enables secure coil placement and effective neck coverage in anatomically challenging cases 3 . Three primary mechanisms of iatrogenic aneurysm perforation during endovascular treatment have been described: perforation caused by the guidewire, the microcatheter, or the coils 4 , 5 . Reported incidence rates range from 2–4.4%, with a significantly higher risk observed in small aneurysms—especially those measuring less than 4 mm in maximum diameter 4 , 6 , 7 . Iatrogenic perforation of cerebral aneurysms during endovascular treatment represents a serious complication, associated with morbidity and mortality rates of up to 39% 8 . The pEGASUS-HPC stent, developed by Phenox GmbH (Bochum, Germany), is a low-profile, self-expanding, laser-cut stent with an open-cell design. It was specifically engineered to conform to various intracranial vessel anatomies and is intended for the treatment of wide-neck aneurysms, arterial dissections, and intracranial stenosis 9 , 10 . Its compatibility with standard 0.0165" inner diameter microcatheters used for coiling procedures eliminates the need for microcatheter exchange, thereby simplifying the intervention. Furthermore, the stent is coated with a hydrophilic polymer (HPC) that reduces thrombogenicity by limiting platelet adhesion to its surface 11 , 12 . The pusher-assisted catheterization (PAC) technique using the pEGASUS-HPC stent pusher was first described by Alhaj Moustafa et al. in a multicenter retrospective study investigating its use in conventional stent-assisted coiling (SAC) of non-ruptured cerebral aneurysms 13 . Their findings demonstrated high catheterization success rates, significantly reduced procedure time compared to standard microwire-assisted techniques, and a favorable safety profile without procedure-related complications. Building upon these promising results, the present study applies the PAC technique specifically in the context of Y-stent-assisted coiling of wide-necked aneurysms—an anatomically and technically more demanding setting. Our aim was to evaluate whether the advantages of PAC, previously demonstrated in straightforward anatomical settings, also apply to bifurcation aneurysms requiring dual-stent constructs in a Y-configuration. METHODS Study Design: This retrospective analysis was conducted across four neurovascular centers, including all consecutive cases treated between June 2021 and June 2025. The study protocol received approval from the local ethics committee (IRB: XXXXXXX). Due to the retrospective nature of the study and the use of fully anonymized data, the requirement for informed consent was waived. Study Participants: All patients with intracranial wide-necked aneurysms treated by Y-stent-assisted coiling (Y-SAC) using the pEGASUS-HPC stent were included in this study. Wide-necked aneurysms were defined as those with a neck diameter ≥ 4 mm or a dome-to-neck ratio < 2, based on previously established criteria in the literature 14 . Only electively treated, unruptured aneurysms were eligible for inclusion. Patients with acutely ruptured aneurysms were excluded. No additional exclusion criteria were applied and no exclusions were made for other reasons. Endovascular Procedures: All procedures were performed using the pEGASUS-HPC stent system (Phenox GmbH, Bochum, Germany), with two stents deployed in a Y-configuration across the aneurysm neck to reconstruct the bifurcation within the parent vessels. The microcatheter employed for stent delivery was retained for subsequent coil placement, thereby eliminating the need for catheter exchange 13 . Catheterization of the aneurysm sac was achieved by advancing the microcatheter through the cells of the implanted stents. Patients were categorized into two groups according to the catheterization technique used: in the MAC group (n = 23), navigation was facilitated using a Synchro® 0.014” × 215 cm microwire (Stryker®); in the PAC group (n = 25), the pEGASUS stent pusher itself served as a guiding element for advancing the microcatheter into the aneurysm sac (Fig. 1 ). Data Collection: All data were collected in anonymized form and encompassed patient-related variables (age, sex), detailed aneurysm characteristics (including size, neck width, anatomical location, and number of aneurysms per patient), as well as procedural information. The latter included the specific catheterization technique used, duration of catheterization, type of navigation method (microwire or stent pusher), and the stent and coil systems applied. Information on peri-procedural antiplatelet management—such as drug regimen, treatment duration, and response testing—was also recorded. Furthermore, intraoperative complications (e.g., aneurysm perforation, vasospasm, and arterial dissection) and the technical success of aneurysm access were systematically documented. Procedural Endpoints: The main procedural outcomes assessed were the success of aneurysm catheterization and the duration required for catheter navigation. Successful catheterization was defined as the ability to advance the coiling microcatheter through the stent cells with accurate placement of its tip within the aneurysm sac. Catheterization time was measured from the moment of stent deployment to the point at which the microcatheter was correctly positioned for coil delivery. Safety Endpoints: Safety assessment focused on the occurrence of intraprocedural complications. Aneurysm perforation was defined as the unintended penetration of the aneurysm wall by the microwire, microcatheter, or embolization coil, resulting in contrast extravasation visible on angiography and indicating subarachnoid leakage. Prompt detection of such events is essential to reduce the risk of serious morbidity and mortality 8 , 15 . Accordingly, as part of the standardized safety protocol, a low-volume contrast injection via the intermediate catheter was routinely performed immediately after aneurysm catheterization. Arterial dissection was characterized by an intimal tear leading to intramural hematoma formation and separation of the vessel wall layers, typically presenting with angiographic signs such as a double-lumen configuration, string sign, or intimal flap 16 – 18 . Advanced imaging techniques, such as diffusion-weighted imaging (DWI), are currently under investigation as a tool for improving the early detection of such dissections 19 . Temporary vasospasm was defined as a transient, angiographically confirmed narrowing of the vessel lumen due to vascular smooth muscle contraction 20 . Other potential complications unrelated to aneurysm access—such as air embolism, thromboembolic events, or distal vessel occlusion—were also systematically evaluated, but none occurred in the present cohort. Antiplatelet Regimen: All patients were premedicated with dual antiplatelet therapy, comprising prasugrel (10 mg once daily) and acetylsalicylic acid (100 mg once daily), starting five days before the scheduled endovascular intervention. On the day of treatment, platelet function testing was performed using the VerifyNow® system (Werfen) to confirm therapeutic efficacy. No cases of inadequate response were detected; all patients exhibited sufficient platelet inhibition. Statistical Analysis: Data processing and analysis were conducted using SPSS software (IBM, Version 25, Windows). The distribution of continuous variables was evaluated using the Shapiro–Wilk test. Descriptive statistics are reported as mean ± standard deviation (SD) for normally distributed data, or as median with interquartile range (IQR) for non-normally distributed variables. Categorical data are presented as absolute frequencies and percentages. Group comparisons for continuous variables were performed using the independent Student’s t-test or the Mann–Whitney U test, depending on data normality. Associations between categorical variables were assessed using the Chi-square test or Fisher’s exact test, where applicable. A p-value below 0.05 (two-tailed) was considered indicative of statistical significance. RESULTS Demographic and clinical characteristics : Between June 2021 and June 2025, a total of 42 patients with 48 incidental, unruptured intracranial aneurysms underwent elective Y-stent-assisted coiling (Y-SAC) using two pEGASUS-HPC stents per case. The mean patient age was 62.6 ± 9.8 years, with 64.3% of patients being female (n = 27). The aneurysms had an average neck width of 4.6 ± 1.7 mm, a mean sac width of 5.9 ± 2.9 mm, and a mean sac depth of 5.3 ± 3.1 mm. The mean dome-to-neck ratio was 1.3 ± 0.7. The most frequent aneurysm location was the anterior communicating artery (AComA, n = 16; 33.3%), followed by the basilar artery (BA, n = 14; 29.2%) and the middle cerebral artery (MCA, n = 12; 25%). Aneurysms in the anterior circulation (n = 34; 70.8%) were more common than those in the posterior circulation. With regard to laterality, 20.8% (n = 10) of aneurysms were located on the left side, 16.7% (n = 8) on the right, and 62.5% (n = 30) were located midline in the AComA or BA. All aneurysms were saccular and had not been previously treated (Table 1 ). Table 1 Demographic, clinical, and imaging characteristics. AcomA, anterior communicating artery. BA, basilar artery. ICA, internal carotid artery. MCA, middle cerebral artery. PcomA, posterior communicating artery. MAC, microwire-assisted catheterization. PAC, pusher-assisted catheterization. SD, standard deviation. Parameters N (%) / Mean ± SD Group All MAC group PAC group Patient characteristics (n = 42) Number of Patients 42 (100%) 23 (54.8%) 19 (45.2%) Age, years 62.6 ± 9.8 63.4 ± 10.2 61.9 ± 9.5 Gender, female 27 (64.3%) 14 (60.9%) 13 (68.4%) Aneurysm characteristics (n = 48) Number of aneurysms 48 (100%) 23 (47.9%) 25 (52.1%) Aneurysm Location AcomA 16 (33.3%) 8 (34.8%) 8 (32%) BA 14 (29.2%) 6 (26.1%) 8 (32%) MCA 12 (25%) 6 (26.1%) 6 (24%) ICA 3 (6.2%) 1 (4.3%) 2 (8%) PcomA 3 (6.2%) 2 (8.7%) 1 (4%) Anterior vs. Posterior Anterior 34 (70.8%) 16 (69.6%) 18 (72%) Aneurysm Laterality Left 10 (20.8%) 7 (30.4%) 7 (28%) Right 8 (16.7%) 5 (21.7%) 5 (20%) Midline 30 (62.5%) 4 (17.4%) 4 (16%) Aneurysm Neck-Width 4.6 ± 1.7 4.7 ± 1.6 4.5 ± 1.8 Aneurysm Sack-Width 5.9 ± 2.9 6.0 ± 2.8 5.8 ± 2.9 Aneurysm Sack-depth 5.3 ± 3.1 5.5 ± 3.2 5.1 ± 3.0 Dome to neck Ratio 1.3 ± 0.7 1.2 ± 0.6 1.3 ± 0.7 Procedural Endpoints: In the MAC group, aneurysm catheterization was successful in all 23 cases (100%), with a mean catheterization time of 319 ± 72 seconds (5.31 ± 1.2 minutes). In the PAC group, catheterization was successful in 22 out of 25 cases (88%). The mean catheterization time was significantly shorter at 49 ± 16 seconds (0.82 ± 0.27 minutes). While the difference in catheterization success did not reach statistical significance (p = 0.235, Fisher’s exact test), the reduction in catheterization time in the PAC group was statistically significant (p < 0.001, unpaired two-tailed t-test). In all three unsuccessful PAC cases, aneurysm catheterization was successfully achieved using a microwire (Table 2 ). Table 2 Catheterization success, catheterization time, and procedural complications. MAC, microwire-assisted catheterization. PAC, pusher-assisted catheterization. SD, standard deviation. Parameters N (%) / Mean ± SD MAC group (n = 23) PAC group (n = 25) Catheterization success, n (%) 23 (100%) 22 (95%) Catheterization time, seconds (mean ± SD) 319 ± 72 49 ± 16 Catheterization time, minutes (mean ± SD) 5.31 ± 1.2 0.82 ± 0.27 Perforations, n (%) 0 (0%) 0 (0%) Vasospasms, n (%) 3 (13%) 4 (16%) Dissections, n (%) 0 (0%) 0 (0%) Procedural Complications: No intraprocedural aneurysm perforations or dissections were observed in either group. Temporary vasospasm occurred in 3 cases (13%) in the MAC group—affecting the vertebral artery (n = 1) and internal carotid artery (n = 2)—and in 4 cases (16%) in the PAC group (vertebral artery: n = 2; internal carotid artery: n = 2). In all instances, vasospasm developed during navigation of the triaxial system through tortuous vessel anatomy. Treatment consisted of intra-arterial infusion of 2 mg nimodipine diluted in 1 L of saline via the guiding catheter, resulting in full angiographic resolution during the procedure. No clinical sequelae were observed, and no further periprocedural complications occurred in either group (Table 2 ). DISCUSSION This multicenter retrospective cohort study evaluated the safety and efficacy of a novel catheterization approach—pusher-assisted catheterization (PAC)—for Y-stent-assisted coiling (Y-SAC) of wide-necked, unruptured cerebral aneurysms. In contrast to the conventional microwire-assisted catheterization (MAC) technique, PAC employs the pEGASUS-HPC stent pusher to guide the coiling microcatheter through the stent struts into the aneurysm sac. To our knowledge, this is the first systematic clinical investigation of this technique specifically in the challenging context of dual-stent Y-constructs at intracranial bifurcations. The PAC technique was first introduced by Alhaj Moustafa et al. in the setting of pEGASUS-HPC stent assisted coiling (SAC), where it showed high efficacy and a favorable safety profile 13 . Building upon this prior work, the present study marks a significant advancement by applying the pEGASUS-HPC PAC technique to the technically more demanding setting of wide-necked bifurcation aneurysms, where dual-stent Y-configurations are necessary for adequate neck coverage. The overall safety profile of both techniques (MAC and PAC) was favorable, with no intraprocedural aneurysm perforations or dissections in either group. Temporary vasospasm occurred in 13% of MAC and 16% of PAC cases, typically during triaxial system navigation. All vasospasms resolved completely after intra-arterial nimodipine administration, and no clinical sequelae were observed. These findings suggest that PAC does not increase the risk of procedural complications, even in the technically demanding setting of Y-SAC. The catheterization success rate was slightly lower in the PAC group (88%) compared to 100% in the MAC group; however, this difference did not reach statistical significance (p = 0.235). Importantly, all failed PAC attempts were successfully salvaged by switching to MAC, demonstrating that the technique can be safely integrated into existing workflows. As observed in the original description of PAC for SAC, catheterization failures were primarily associated with tangential aneurysm configurations, which may impair the passive alignment of the pusher tip with the aneurysm orifice (Fig. 2 ). The most striking advantage of PAC was its marked reduction in catheterization time. With an average access time of 0.82 ± 0.27 minutes, PAC was approximately 6.5 times faster than MAC (5.31 ± 1.2 minutes, p < 0.001). This result is consistent with previous findings from the single-stent SAC and highlights the applicability of PAC even in Y-stenting procedures, where vascular anatomy and dual-stent configurations are more complex and catheterization inherently more demanding. The significant time savings associated with PAC may translate into reduced fluoroscopy exposure, lower contrast volume, and decreased operator fatigue—factors that collectively improve procedural safety and efficiency. Another theoretical advantage of PAC lies in the elimination of microwire manipulation within or near the aneurysm sac. Given that guidewire-related perforation is a well-recognized cause of intraprocedural rupture—especially in small, fragile, or posterior circulation aneurysms—the use of a blunt, atraumatic stent pusher as a guiding element may lower this risk. Although no perforations occurred in this study, the concept of minimizing intraluminal manipulation remains highly relevant and deserves further investigation in larger, risk-stratified populations. Overall, the PAC technique appears particularly effective in favorable aneurysm orientations, where the sac aligns coaxially with the parent vessel, allowing smooth advancement of the microcatheter over the pusher. In anatomically complex or tangential configurations, MAC remains a reliable and immediately available fallback strategy. Limitations This study has several limitations. Its retrospective nature introduces a potential for selection and performance bias. Although the sample size exceeds that of many comparable Y-stenting series, it remains relatively modest. The exclusive use of the pEGASUS-HPC stent limits generalizability, as performance may differ with other stent platforms. Furthermore, long-term clinical and angiographic follow-up was not the focus of this study and must be addressed in future prospective trials. Conclusion The pEGASUS-HPC PAC technique appears to offer a safe, effective, and significantly time-saving alternative to conventional microwire navigation in Y-stent-assisted coiling of unruptured wide-necked bifurcation aneurysms. While its success appears to be influenced by anatomical configuration, the PAC technique may offer meaningful procedural advantages in appropriately selected cases. Future prospective studies with larger patient cohorts and diverse stent platforms are warranted to validate these preliminary findings and assess their broader clinical applicability. Abbreviations ACA anterior cerebral artery AComA anterior communicating artery BA basilar artery DWI diffusion-weighted imaging HPC hydrophilic polymer coating ICA internal carotid artery i.a. intra-arterial IRB institutional review board IQR interquartile range MAC microwire-assisted catheterization MCA middle cerebral artery PAC pEGASUS HPC stent pusher-assisted catheterization PComA posterior communicating artery SAC stent-assisted coiling SD standard deviation VA vertebral artery Declarations Conflicts of Interest: All other authors declare no conflicts of interest Ethical Approval and Consent: The study was approved by the local ethics committee (IRB: XX-XXXXX). Informed consent was waived due to the completely retrospective and anonymized nature of the data analysis. Competing Interests All authors declare no conflicts of interest. Funding: No funding was received for this study. Author Contribution M.A. conceived the study, coordinated data collection across centers, performed statistical analysis, and drafted the main manuscript text. B.A.M., A.K., M.D., A.A., J.K., S.F., and Z.A. contributed to case acquisition, data collection, and interpretation. C.N., A.G., and M.G. contributed to study design and critically revised the manuscript for important intellectual content. H.H. and A.K. supervised the project, provided critical revisions, and ensured methodological accuracy. All authors reviewed and approved the final version of the manuscript References Biondi A, Janardhan V, Katz JM et al (2007) Neuroform stent-assisted coil embolization of wide-neck intracranial aneurysms: strategies in stent deployment and midterm follow-up. Neurosurgery ; 61: 460–468; discussion 468–469. 10.1227/01.NEU.0000290890.62201.A9 Kim BM, Kim DJ, Kim DI (2011) Stent application for the treatment of cerebral aneurysms. 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Marburg","correspondingAuthor":false,"prefix":"","firstName":"Abdallah","middleName":"","lastName":"Aburub","suffix":""},{"id":515825645,"identity":"bf0eb532-c124-43ad-a608-91ee53cb55a2","order_by":8,"name":"Julia Korthäuer","email":"","orcid":"","institution":"Stiftungsklinikum Mittelrhein","correspondingAuthor":false,"prefix":"","firstName":"Julia","middleName":"","lastName":"Korthäuer","suffix":""},{"id":515825647,"identity":"18c5d21f-b6e5-43c4-9b9b-6b6431c48d5a","order_by":9,"name":"Stephan Felber","email":"","orcid":"","institution":"Stiftungsklinikum Mittelrhein","correspondingAuthor":false,"prefix":"","firstName":"Stephan","middleName":"","lastName":"Felber","suffix":""},{"id":515825648,"identity":"2c865c1b-566d-4d86-83d3-7c2038412648","order_by":10,"name":"Zakarya Ali","email":"","orcid":"","institution":"Sana Klinikum Offenbach","correspondingAuthor":false,"prefix":"","firstName":"Zakarya","middleName":"","lastName":"Ali","suffix":""},{"id":515825650,"identity":"b863fa55-db5a-4dd8-a17c-8fc78cfd5340","order_by":11,"name":"Hans Henkes","email":"","orcid":"","institution":"Klinikum Stuttgart","correspondingAuthor":false,"prefix":"","firstName":"Hans","middleName":"","lastName":"Henkes","suffix":""},{"id":515825651,"identity":"ce51a86e-a456-4ded-a864-2e90478c5594","order_by":12,"name":"André Kemmling","email":"","orcid":"","institution":"Philipps University of Marburg","correspondingAuthor":false,"prefix":"","firstName":"André","middleName":"","lastName":"Kemmling","suffix":""}],"badges":[],"createdAt":"2025-09-05 08:23:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7542254/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7542254/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00234-025-03838-0","type":"published","date":"2025-11-15T15:58:48+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":91836127,"identity":"02190e33-3674-4d05-8f24-a509013c92ff","added_by":"auto","created_at":"2025-09-22 09:36:07","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":78176,"visible":true,"origin":"","legend":"","description":"","filename":"AnonymousMainDocument.docx","url":"https://assets-eu.researchsquare.com/files/rs-7542254/v1/62d5a7ca0291e60099c3cb23.docx"},{"id":91839560,"identity":"6caa0aa4-a321-4a07-a09f-1684a0a840b8","added_by":"auto","created_at":"2025-09-22 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09:28:07","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":66843,"visible":true,"origin":"","legend":"","description":"","filename":"12f3ddaa0fc343b4bdb9c5181ebc1bb11structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7542254/v1/c73991c09ba629734d607c43.xml"},{"id":91836129,"identity":"360d6419-b4e3-4171-99b7-f2dc1a96bc9a","added_by":"auto","created_at":"2025-09-22 09:36:07","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":75308,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7542254/v1/03c99ed72832103b5812a7f8.html"},{"id":91834906,"identity":"4697c43d-0e8e-468b-b157-49718b8fb42a","added_by":"auto","created_at":"2025-09-22 09:28:07","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":165403,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eIllustration of the pEGASUS stent pusher-assisted catheterization (PAC) technique for Y-stent-assisted coiling of a bifurcation aneurysm.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1- Stent pusher tip. 2- Second deployed pEGASUS HPC stent. 3- First deployed pEGASUS HPC stent. 4- Microcatheter used for stent delivery and subsequent coiling. 5- The sac of the aneurysm. 6- Coils.\u003c/p\u003e\n\u003cp\u003e(A) Anatomy after placement of two pEGASUS HPC stents in a Y-configuration across the aneurysm neck. \u003cbr\u003e\n(B) Advancement of the microcatheter toward the level of the neck of the aneurysm.\u003cbr\u003e\n(C) Retraction of the stent pusher tip to the aneurysm level.\u003cbr\u003e\n(D) Advancement of the stent pusher tip through the stent struts into the aneurysm sac.\u003cbr\u003e\n(E) Navigation of the microcatheter into the aneurysm, using the pusher as a rail.\u003cbr\u003e\n(F) Withdrawal of the stent pusher and subsequent coil embolization of the aneurysm.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7542254/v1/1ee09e69e682a4e760f1239a.jpg"},{"id":91834901,"identity":"3a4b459b-a2e6-458a-b95c-4dd37da09152","added_by":"auto","created_at":"2025-09-22 09:28:07","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":63995,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSchematic demonstrating anatomical limitation of the PAC technique. In this example, the aneurysm arises tangentially from the parent vessel, preventing coaxial alignment of the stent pusher with the aneurysm neck and resulting in unsuccessful catheterization.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e1- Stent pusher tip. 2- Second deployed pEGASUS HPC stent. 3- First deployed pEGASUS HPC stent. 4- Microcatheter used for stent delivery and intended for coiling. 5- The sac of the aneurysm.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7542254/v1/21f8d7fe15fb78d65d1aa61f.jpg"},{"id":96105308,"identity":"c4951be0-65b0-4ab3-98a6-3528f1a238a0","added_by":"auto","created_at":"2025-11-17 16:11:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1125934,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7542254/v1/a12609cf-9634-4070-8da8-c30d0439c13b.pdf"}],"financialInterests":"Competing interest reported. All authors declare no conflicts of interest.","formattedTitle":"pEGASUS-HPC Stent Pusher-Assisted Catheterization (PAC) Technique in Y-Stent-Assisted Coiling of Unruptured Wide-Necked Cerebral Aneurysms: A Multicenter Retrospective Study","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eIn stent-assisted coiling (SAC), two commonly used techniques exist for positioning the tip of the coiling microcatheter within the aneurysm sac, depending on the procedural strategy. The first, known as the jailing technique, involves placing the coiling microcatheter into the aneurysm sac before deploying a stent via a second microcatheter in the parent vessel, thereby trapping (or \"jailing\") the coiling catheter between the stent and the vessel wall. The second approach entails first deploying the stent, followed by navigating the coiling microcatheter through the stent struts into the aneurysm sac\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. In the present study, the latter technique was applied in all cases.\u003c/p\u003e\u003cp\u003eAmong the various advanced SAC techniques, Y-stenting has gained particular relevance for bifurcation aneurysms, where conventional strategies often fall short. By creating a Y-shaped scaffold at the vessel bifurcation, this approach enables secure coil placement and effective neck coverage in anatomically challenging cases\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThree primary mechanisms of iatrogenic aneurysm perforation during endovascular treatment have been described: perforation caused by the guidewire, the microcatheter, or the coils\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. Reported incidence rates range from 2\u0026ndash;4.4%, with a significantly higher risk observed in small aneurysms\u0026mdash;especially those measuring less than 4 mm in maximum diameter\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eIatrogenic perforation of cerebral aneurysms during endovascular treatment represents a serious complication, associated with morbidity and mortality rates of up to 39%\u003csup\u003e8\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe pEGASUS-HPC stent, developed by Phenox GmbH (Bochum, Germany), is a low-profile, self-expanding, laser-cut stent with an open-cell design. It was specifically engineered to conform to various intracranial vessel anatomies and is intended for the treatment of wide-neck aneurysms, arterial dissections, and intracranial stenosis\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. Its compatibility with standard 0.0165\" inner diameter microcatheters used for coiling procedures eliminates the need for microcatheter exchange, thereby simplifying the intervention. Furthermore, the stent is coated with a hydrophilic polymer (HPC) that reduces thrombogenicity by limiting platelet adhesion to its surface\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe pusher-assisted catheterization (PAC) technique using the pEGASUS-HPC stent pusher was first described by Alhaj Moustafa et al. in a multicenter retrospective study investigating its use in conventional stent-assisted coiling (SAC) of non-ruptured cerebral aneurysms\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Their findings demonstrated high catheterization success rates, significantly reduced procedure time compared to standard microwire-assisted techniques, and a favorable safety profile without procedure-related complications. Building upon these promising results, the present study applies the PAC technique specifically in the context of Y-stent-assisted coiling of wide-necked aneurysms\u0026mdash;an anatomically and technically more demanding setting. Our aim was to evaluate whether the advantages of PAC, previously demonstrated in straightforward anatomical settings, also apply to bifurcation aneurysms requiring dual-stent constructs in a Y-configuration.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Design:\u003c/h2\u003e\u003cp\u003eThis retrospective analysis was conducted across four neurovascular centers, including all consecutive cases treated between June 2021 and June 2025. The study protocol received approval from the local ethics committee (IRB: XXXXXXX). Due to the retrospective nature of the study and the use of fully anonymized data, the requirement for informed consent was waived.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eStudy Participants:\u003c/h3\u003e\n\u003cp\u003eAll patients with intracranial wide-necked aneurysms treated by Y-stent-assisted coiling (Y-SAC) using the pEGASUS-HPC stent were included in this study. Wide-necked aneurysms were defined as those with a neck diameter\u0026thinsp;\u0026ge;\u0026thinsp;4 mm or a dome-to-neck ratio\u0026thinsp;\u0026lt;\u0026thinsp;2, based on previously established criteria in the literature\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Only electively treated, unruptured aneurysms were eligible for inclusion. Patients with acutely ruptured aneurysms were excluded. No additional exclusion criteria were applied and no exclusions were made for other reasons.\u003c/p\u003e\n\u003ch3\u003eEndovascular Procedures:\u003c/h3\u003e\n\u003cp\u003eAll procedures were performed using the pEGASUS-HPC stent system (Phenox GmbH, Bochum, Germany), with two stents deployed in a Y-configuration across the aneurysm neck to reconstruct the bifurcation within the parent vessels. The microcatheter employed for stent delivery was retained for subsequent coil placement, thereby eliminating the need for catheter exchange\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Catheterization of the aneurysm sac was achieved by advancing the microcatheter through the cells of the implanted stents. Patients were categorized into two groups according to the catheterization technique used: in the MAC group (n\u0026thinsp;=\u0026thinsp;23), navigation was facilitated using a Synchro\u0026reg; 0.014\u0026rdquo; \u0026times; 215 cm microwire (Stryker\u0026reg;); in the PAC group (n\u0026thinsp;=\u0026thinsp;25), the pEGASUS stent pusher itself served as a guiding element for advancing the microcatheter into the aneurysm sac (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eData Collection:\u003c/h3\u003e\n\u003cp\u003eAll data were collected in anonymized form and encompassed patient-related variables (age, sex), detailed aneurysm characteristics (including size, neck width, anatomical location, and number of aneurysms per patient), as well as procedural information. The latter included the specific catheterization technique used, duration of catheterization, type of navigation method (microwire or stent pusher), and the stent and coil systems applied. Information on peri-procedural antiplatelet management\u0026mdash;such as drug regimen, treatment duration, and response testing\u0026mdash;was also recorded. Furthermore, intraoperative complications (e.g., aneurysm perforation, vasospasm, and arterial dissection) and the technical success of aneurysm access were systematically documented.\u003c/p\u003e\n\u003ch3\u003eProcedural Endpoints:\u003c/h3\u003e\n\u003cp\u003eThe main procedural outcomes assessed were the success of aneurysm catheterization and the duration required for catheter navigation. Successful catheterization was defined as the ability to advance the coiling microcatheter through the stent cells with accurate placement of its tip within the aneurysm sac. Catheterization time was measured from the moment of stent deployment to the point at which the microcatheter was correctly positioned for coil delivery.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eSafety Endpoints:\u003c/h2\u003e\u003cp\u003eSafety assessment focused on the occurrence of intraprocedural complications. Aneurysm perforation was defined as the unintended penetration of the aneurysm wall by the microwire, microcatheter, or embolization coil, resulting in contrast extravasation visible on angiography and indicating subarachnoid leakage. Prompt detection of such events is essential to reduce the risk of serious morbidity and mortality\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Accordingly, as part of the standardized safety protocol, a low-volume contrast injection via the intermediate catheter was routinely performed immediately after aneurysm catheterization. Arterial dissection was characterized by an intimal tear leading to intramural hematoma formation and separation of the vessel wall layers, typically presenting with angiographic signs such as a double-lumen configuration, string sign, or intimal flap\u003csup\u003e\u003cspan additionalcitationids=\"CR17\" citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Advanced imaging techniques, such as diffusion-weighted imaging (DWI), are currently under investigation as a tool for improving the early detection of such dissections\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Temporary vasospasm was defined as a transient, angiographically confirmed narrowing of the vessel lumen due to vascular smooth muscle contraction\u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. Other potential complications unrelated to aneurysm access\u0026mdash;such as air embolism, thromboembolic events, or distal vessel occlusion\u0026mdash;were also systematically evaluated, but none occurred in the present cohort.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eAntiplatelet Regimen:\u003c/h3\u003e\n\u003cp\u003eAll patients were premedicated with dual antiplatelet therapy, comprising prasugrel (10 mg once daily) and acetylsalicylic acid (100 mg once daily), starting five days before the scheduled endovascular intervention. On the day of treatment, platelet function testing was performed using the VerifyNow\u0026reg; system (Werfen) to confirm therapeutic efficacy. No cases of inadequate response were detected; all patients exhibited sufficient platelet inhibition.\u003c/p\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis:\u003c/h2\u003e\u003cp\u003eData processing and analysis were conducted using SPSS software (IBM, Version 25, Windows). The distribution of continuous variables was evaluated using the Shapiro\u0026ndash;Wilk test. Descriptive statistics are reported as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) for normally distributed data, or as median with interquartile range (IQR) for non-normally distributed variables. Categorical data are presented as absolute frequencies and percentages. Group comparisons for continuous variables were performed using the independent Student\u0026rsquo;s t-test or the Mann\u0026ndash;Whitney U test, depending on data normality. Associations between categorical variables were assessed using the Chi-square test or Fisher\u0026rsquo;s exact test, where applicable. A p-value below 0.05 (two-tailed) was considered indicative of statistical significance.\u003c/p\u003e\u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e\u003cb\u003eDemographic and clinical characteristics\u003c/b\u003e:\u003c/h2\u003e\u003cp\u003eBetween June 2021 and June 2025, a total of 42 patients with 48 incidental, unruptured intracranial aneurysms underwent elective Y-stent-assisted coiling (Y-SAC) using two pEGASUS-HPC stents per case. The mean patient age was 62.6\u0026thinsp;\u0026plusmn;\u0026thinsp;9.8 years, with 64.3% of patients being female (n\u0026thinsp;=\u0026thinsp;27). The aneurysms had an average neck width of 4.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7 mm, a mean sac width of 5.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9 mm, and a mean sac depth of 5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1 mm. The mean dome-to-neck ratio was 1.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7. The most frequent aneurysm location was the anterior communicating artery (AComA, n\u0026thinsp;=\u0026thinsp;16; 33.3%), followed by the basilar artery (BA, n\u0026thinsp;=\u0026thinsp;14; 29.2%) and the middle cerebral artery (MCA, n\u0026thinsp;=\u0026thinsp;12; 25%). Aneurysms in the anterior circulation (n\u0026thinsp;=\u0026thinsp;34; 70.8%) were more common than those in the posterior circulation. With regard to laterality, 20.8% (n\u0026thinsp;=\u0026thinsp;10) of aneurysms were located on the left side, 16.7% (n\u0026thinsp;=\u0026thinsp;8) on the right, and 62.5% (n\u0026thinsp;=\u0026thinsp;30) were located midline in the AComA or BA. All aneurysms were saccular and had not been previously treated (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eDemographic, clinical, and imaging characteristics.\u003c/b\u003e AcomA, anterior communicating artery. BA, basilar artery. ICA, internal carotid artery. MCA, middle cerebral artery. PcomA, posterior communicating artery. MAC, microwire-assisted catheterization. PAC, pusher-assisted catheterization. SD, standard deviation.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eParameters\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c5\" namest=\"c3\"\u003e\u003cp\u003eN (%) / Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eGroup\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAll\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMAC group\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePAC group\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003ePatient characteristics (n\u0026thinsp;=\u0026thinsp;42)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eNumber of Patients\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e42 (100%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e23 (54.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e19 (45.2%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAge, years\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e62.6\u0026thinsp;\u0026plusmn;\u0026thinsp;9.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e63.4\u0026thinsp;\u0026plusmn;\u0026thinsp;10.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e61.9\u0026thinsp;\u0026plusmn;\u0026thinsp;9.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eGender, female\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e27 (64.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e14 (60.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13 (68.4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e\u003cp\u003eAneurysm characteristics (n\u0026thinsp;=\u0026thinsp;48)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eNumber of aneurysms\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e48 (100%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e23 (47.9%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e25 (52.1%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e\u003cp\u003eAneurysm Location\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAcomA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16 (33.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8 (34.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8 (32%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e14 (29.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6 (26.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8 (32%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMCA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12 (25%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6 (26.1%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6 (24%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eICA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (6.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (4.3%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2 (8%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePcomA\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (6.2%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2 (8.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1 (4%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAnterior vs. Posterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAnterior\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e34 (70.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e16 (69.6%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e18 (72%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eAneurysm Laterality\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLeft\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10 (20.8%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7 (30.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e7 (28%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRight\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8 (16.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5 (21.7%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5 (20%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMidline\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 (62.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4 (17.4%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4 (16%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAneurysm Neck-Width\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAneurysm Sack-Width\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5.8\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAneurysm Sack-depth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eDome to neck Ratio\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eProcedural Endpoints:\u003c/h2\u003e\u003cp\u003eIn the MAC group, aneurysm catheterization was successful in all 23 cases (100%), with a mean catheterization time of 319\u0026thinsp;\u0026plusmn;\u0026thinsp;72 seconds (5.31\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 minutes). In the PAC group, catheterization was successful in 22 out of 25 cases (88%). The mean catheterization time was significantly shorter at 49\u0026thinsp;\u0026plusmn;\u0026thinsp;16 seconds (0.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.27 minutes). While the difference in catheterization success did not reach statistical significance (p\u0026thinsp;=\u0026thinsp;0.235, Fisher\u0026rsquo;s exact test), the reduction in catheterization time in the PAC group was statistically significant (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, unpaired two-tailed t-test). In all three unsuccessful PAC cases, aneurysm catheterization was successfully achieved using a microwire (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003e\u003cb\u003eCatheterization success, catheterization time, and procedural complications.\u003c/b\u003e MAC, microwire-assisted catheterization. PAC, pusher-assisted catheterization. SD, standard deviation.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameters\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e\u003cp\u003eN (%) / Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMAC group (n\u0026thinsp;=\u0026thinsp;23)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePAC group (n\u0026thinsp;=\u0026thinsp;25)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCatheterization success, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e23 (100%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e22 (95%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCatheterization time, seconds (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e319\u0026thinsp;\u0026plusmn;\u0026thinsp;72\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e49\u0026thinsp;\u0026plusmn;\u0026thinsp;16\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCatheterization time, minutes (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.31\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.27\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePerforations, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVasospasms, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (13%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4 (16%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDissections, n (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0 (0%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003eProcedural Complications:\u003c/h2\u003e\u003cp\u003eNo intraprocedural aneurysm perforations or dissections were observed in either group. Temporary vasospasm occurred in 3 cases (13%) in the MAC group\u0026mdash;affecting the vertebral artery (n\u0026thinsp;=\u0026thinsp;1) and internal carotid artery (n\u0026thinsp;=\u0026thinsp;2)\u0026mdash;and in 4 cases (16%) in the PAC group (vertebral artery: n\u0026thinsp;=\u0026thinsp;2; internal carotid artery: n\u0026thinsp;=\u0026thinsp;2). In all instances, vasospasm developed during navigation of the triaxial system through tortuous vessel anatomy. Treatment consisted of intra-arterial infusion of 2 mg nimodipine diluted in 1 L of saline via the guiding catheter, resulting in full angiographic resolution during the procedure. No clinical sequelae were observed, and no further periprocedural complications occurred in either group (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis multicenter retrospective cohort study evaluated the safety and efficacy of a novel catheterization approach\u0026mdash;pusher-assisted catheterization (PAC)\u0026mdash;for Y-stent-assisted coiling (Y-SAC) of wide-necked, unruptured cerebral aneurysms. In contrast to the conventional microwire-assisted catheterization (MAC) technique, PAC employs the pEGASUS-HPC stent pusher to guide the coiling microcatheter through the stent struts into the aneurysm sac. To our knowledge, this is the first systematic clinical investigation of this technique specifically in the challenging context of dual-stent Y-constructs at intracranial bifurcations.\u003c/p\u003e\u003cp\u003eThe PAC technique was first introduced by Alhaj Moustafa et al. in the setting of pEGASUS-HPC stent assisted coiling (SAC), where it showed high efficacy and a favorable safety profile\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Building upon this prior work, the present study marks a significant advancement by applying the pEGASUS-HPC PAC technique to the technically more demanding setting of wide-necked bifurcation aneurysms, where dual-stent Y-configurations are necessary for adequate neck coverage.\u003c/p\u003e\u003cp\u003eThe overall safety profile of both techniques (MAC and PAC) was favorable, with no intraprocedural aneurysm perforations or dissections in either group. Temporary vasospasm occurred in 13% of MAC and 16% of PAC cases, typically during triaxial system navigation. All vasospasms resolved completely after intra-arterial nimodipine administration, and no clinical sequelae were observed. These findings suggest that PAC does not increase the risk of procedural complications, even in the technically demanding setting of Y-SAC.\u003c/p\u003e\u003cp\u003eThe catheterization success rate was slightly lower in the PAC group (88%) compared to 100% in the MAC group; however, this difference did not reach statistical significance (p\u0026thinsp;=\u0026thinsp;0.235). Importantly, all failed PAC attempts were successfully salvaged by switching to MAC, demonstrating that the technique can be safely integrated into existing workflows. As observed in the original description of PAC for SAC, catheterization failures were primarily associated with tangential aneurysm configurations, which may impair the passive alignment of the pusher tip with the aneurysm orifice (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe most striking advantage of PAC was its marked reduction in catheterization time. With an average access time of 0.82\u0026thinsp;\u0026plusmn;\u0026thinsp;0.27 minutes, PAC was approximately 6.5 times faster than MAC (5.31\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2 minutes, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This result is consistent with previous findings from the single-stent SAC and highlights the applicability of PAC even in Y-stenting procedures, where vascular anatomy and dual-stent configurations are more complex and catheterization inherently more demanding. The significant time savings associated with PAC may translate into reduced fluoroscopy exposure, lower contrast volume, and decreased operator fatigue\u0026mdash;factors that collectively improve procedural safety and efficiency.\u003c/p\u003e\u003cp\u003eAnother theoretical advantage of PAC lies in the elimination of microwire manipulation within or near the aneurysm sac. Given that guidewire-related perforation is a well-recognized cause of intraprocedural rupture\u0026mdash;especially in small, fragile, or posterior circulation aneurysms\u0026mdash;the use of a blunt, atraumatic stent pusher as a guiding element may lower this risk. Although no perforations occurred in this study, the concept of minimizing intraluminal manipulation remains highly relevant and deserves further investigation in larger, risk-stratified populations.\u003c/p\u003e\u003cp\u003eOverall, the PAC technique appears particularly effective in favorable aneurysm orientations, where the sac aligns coaxially with the parent vessel, allowing smooth advancement of the microcatheter over the pusher. In anatomically complex or tangential configurations, MAC remains a reliable and immediately available fallback strategy.\u003c/p\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003eLimitations\u003c/h2\u003e\u003cp\u003eThis study has several limitations. Its retrospective nature introduces a potential for selection and performance bias. Although the sample size exceeds that of many comparable Y-stenting series, it remains relatively modest. The exclusive use of the pEGASUS-HPC stent limits generalizability, as performance may differ with other stent platforms. Furthermore, long-term clinical and angiographic follow-up was not the focus of this study and must be addressed in future prospective trials.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe pEGASUS-HPC PAC technique appears to offer a safe, effective, and significantly time-saving alternative to conventional microwire navigation in Y-stent-assisted coiling of unruptured wide-necked bifurcation aneurysms. While its success appears to be influenced by anatomical configuration, the PAC technique may offer meaningful procedural advantages in appropriately selected cases. Future prospective studies with larger patient cohorts and diverse stent platforms are warranted to validate these preliminary findings and assess their broader clinical applicability.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eACA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eanterior cerebral artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eAComA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eanterior communicating artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eBA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ebasilar artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eDWI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ediffusion-weighted imaging\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eHPC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ehydrophilic polymer coating\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eICA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003einternal carotid artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ei.a.\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eintra-arterial\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eIRB\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003einstitutional review board\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eIQR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003einterquartile range\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMAC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003emicrowire-assisted catheterization\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMCA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003emiddle cerebral artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ePAC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003epEGASUS HPC stent pusher-assisted catheterization\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ePComA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eposterior communicating artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eSAC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003estent-assisted coiling\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eSD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003estandard deviation\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eVA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003evertebral artery\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflicts of Interest:\u003c/h2\u003e\u003cp\u003eAll other authors declare no conflicts of interest\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthical Approval and Consent:\u003c/strong\u003e\u003cp\u003e The study was approved by the local ethics committee (IRB: XX-XXXXX). Informed consent was waived due to the completely retrospective and anonymized nature of the data analysis.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003cp\u003eAll authors declare no conflicts of interest.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eNo funding was received for this study.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.A. conceived the study, coordinated data collection across centers, performed statistical analysis, and drafted the main manuscript text. B.A.M., A.K., M.D., A.A., J.K., S.F., and Z.A. contributed to case acquisition, data collection, and interpretation. C.N., A.G., and M.G. contributed to study design and critically revised the manuscript for important intellectual content. H.H. and A.K. supervised the project, provided critical revisions, and ensured methodological accuracy. 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Neuroimaging Clin N Am 31:147\u0026ndash;155. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.nic.2021.01.004\u003c/span\u003e\u003cspan address=\"10.1016/j.nic.2021.01.004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Stent, pusher, pEGASUS HPC, coiling, catheterization","lastPublishedDoi":"10.21203/rs.3.rs-7542254/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7542254/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjectives: \u003c/strong\u003eTo evaluate the safety and efficacy of the pusher-assisted catheterization (PAC) technique using the pEGASUS-HPC stent pusher instead of a microwire for accessing unruptured wide-necked cerebral aneurysms during Y-stent-assisted coiling.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eIn this multicenter retrospective study (July 2021– June 2025), 48 unruptured wide-necked cerebral aneurysms underwent Y-stent-assisted coiling using pEGASUS HPC stents. Based on the catheterization technique, cases were assigned to either the microwire-assisted catheterization (MAC, n=23) or the stent pusher-assisted catheterization (PAC, n=25) group. Clinical and procedural data were analyzed to compare safety and efficacy, focusing on success rates, required catheterization time, complications, and adverse events.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u0026nbsp;\u003c/strong\u003eThe cohort had a mean age of 62.6 ± 9.8 years, with 64.3% of patients being female. In the MAC group, aneurysm catheterization was successful in all 23 cases (100%), with a mean catheterization time of 5.31 ± 1.2 minutes. In contrast, the PAC group achieved successful catheterization in 88% of cases (22/25), with a markedly reduced mean catheterization time of 0.82 ± 0.27 minutes—approximately 6.5 times faster than the conventional MAC technique (p \u0026lt; 0.001). Importantly, no procedure-related complications, such as perforations or dissections, were observed in either group.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThe PAC technique using the pEGASUS-HPC stent appears to be a safe and time-efficient alternative to microwire-assisted catheterization in Y-stent-assisted coiling of unruptured wide-necked cerebral aneurysms. It significantly reduces catheterization time without increasing complication rates. Further studies are needed to confirm these preliminary findings.\u003c/p\u003e","manuscriptTitle":"pEGASUS-HPC Stent Pusher-Assisted Catheterization (PAC) Technique in Y-Stent-Assisted Coiling of Unruptured Wide-Necked Cerebral Aneurysms: A Multicenter Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-22 09:28:02","doi":"10.21203/rs.3.rs-7542254/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"620d09b1-7b0b-494d-9304-f52f245793f0","owner":[],"postedDate":"September 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-11-17T16:07:28+00:00","versionOfRecord":{"articleIdentity":"rs-7542254","link":"https://doi.org/10.1007/s00234-025-03838-0","journal":{"identity":"neuroradiology","isVorOnly":false,"title":"Neuroradiology"},"publishedOn":"2025-11-15 15:58:48","publishedOnDateReadable":"November 15th, 2025"},"versionCreatedAt":"2025-09-22 09:28:02","video":"","vorDoi":"10.1007/s00234-025-03838-0","vorDoiUrl":"https://doi.org/10.1007/s00234-025-03838-0","workflowStages":[]},"version":"v1","identity":"rs-7542254","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7542254","identity":"rs-7542254","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}