Intracranial Aneurysm Location: Key Factor in Ruptures with Internal Carotid Artery Occlusion

Intracranial Aneurysm Location: Key Factor in Ruptures with Internal Carotid Artery Occlusion | 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 Intracranial Aneurysm Location: Key Factor in Ruptures with Internal Carotid Artery Occlusion Pengran Liu, Bangyue Wang, Jing Guo, Hui Dai, Yan Zhao, Wentao Dong, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4793934/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Aug, 2025 Read the published version in BMC Neurology → Version 1 posted 10 You are reading this latest preprint version Abstract Background and Purpose Intracranial aneurysms combined with spontaneous internal carotid artery occlusion (ICAO) are a rare and serious vascular disorder. Currently, there is only limited information available on the clinical characteristics of these patients and the risk factors for aneurysm rupture. Our objective is to describe the clinical features of these patients and predict the risk factors for the rupture of unruptured intracranial aneurysms (UIAs) combined with ICAO. Methods We retrospectively analyzed cases of intracranial aneurysms with concurrent spontaneous ICAO from the Chinese Multicenter Aneurysm Database(CMAD). We collected population demographic characteristics and clinical data using a standardized case questionnaire from CMAD. Binary logistic regression analysis was used to identify risk factors for rupture of UIA associated with combined ICAO. Results We identified 93 patients with intracranial aneurysms combined with ICAO, including 38 females and 55 males, with an average age of 60.7 ± 9.5years (ranging from 32 to 79 years old). Among those with ICAO, 52 had ruptured intracranial aneurysms (RIAs) and 41 had UIAs. Specifically, there were 81 cases of unilateral ICAO, with 16 aneurysms located on the same side as the ICAO, 22 in the midline, and 43 on the opposite side of the ICAO; 12 cases were bilateral ICAO. Binary logistic regression analysis indicated that risk factors associated with the rupture of UIAs with ICAO included bilateral internal carotid artery occlusion and aneurysms in the posterior circulation. Furthermore, multivariate analysis showed that posterior circulation aneurysms are an independent risk factor for the rupture of UIAs with ICAO. Conclusion We have described and analyzed the clinical characteristics and risk factors influencing the rupture of intracranial aneurysms in patients with ICAO. The study found that the location of the aneurysm is an important risk factor for the rupture of UIAs combined with ICAO. subarachnoid hemorrhage intracranial aneurysm internal carotid artery occlusion blood flow risk factors Introduction Among the general population, the prevalence rate of unruptured intracranial aneurysm1 (UIA) is approximately 3.2% [ 1 ] , the annual risk of Subarachnoid hemorrhage (SAH) from UIA is about 1% [ 2 ] . SAH is an extremely serious and potentially fatal condition, with a high mortality and disability rate, most cases of non-traumatic SAH are attributed to the rupture of intracranial aneurysms [ 3 , 4 , 5 , 6 ] . With the widespread use of non-invasive imaging techniques, an increasing number of patients with spontaneous internal carotid artery occlusion (ICAO) are found to have intracranial aneurysms. ICAO is a relatively common cause of stroke and transient ischemic attacks (TIAs), accounting for about 10–15% of all cases [ 7 ] . Therefore, it is believed that the presence of both conditions can elevate the risk of mortality and morbidity even when collateral circulation is adequate. These conditions are more common in older patients who often have significant comorbidities and advanced atherosclerosis. The management of IAs in the presence of ICAO poses a considerable challenge for neurosurgeons due to the potential treatment risks and high rupture probability. Current literature on IAs with ICAO is largelyanecdotal [ 8 – 12 ] , lacking definitive guidelines and consensus for optimal patient management. Existing research has pinpointed potential risk factors for intracranial aneurysm rupture, including size, location, multiplicity, shape, smoking, age, hypertension, hypercholesterolemia, and a history ofSAH [ 13 – 18 ] . Yet, data on rupture risks for UIAs in the context of ICAO remain unreported. Our research is dedicated to exploring the clinical characteristics and risk factors influencing the rupture of intracranial aneurysms associated with ICAO. This exploration aims to deepen our understanding of the causes behind the rupture of IAs in the context of ICAO and to enhance the treatment strategies and prognosis for such conditions. Materials and Methods Patients Data This study used data from the Chinese Multicenter Aneurysm Database (CMAD) (website: http://www.cmadtj.com ; clinical trial No.:ChiCTR2200065083). CMAD is a multicenter research project registered in China, led by Tianjin Medical University General Hospital. The collaborating centers, located in Tianjin, Hebei, Shandong, and Shanxi, have collectively registered over 10,000 cases of cerebral aneurysms. The CMAD data is sourced from medical records. This study was approved by the Ethics Committee of the Tianjin Medical University General Hospital (IRB2021-YX-178-01) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2100054014). All the procedures were performed in accordance with the World Medical Association Declaration of Helsinki [ 19 ] . After being approved, we cross-searched CMAD of patients combining the terms “intracranial aneurysms” and “internal carotid artery occlusion.” The inclusion criteria were as follows: diagnosis of aneurysms with spontaneous occlusion of the internal carotid artery confirmed by at least one examination—computed tomography angiography (CTA), magnetic resonance angiography (MRA), or digital subtraction angiography (DSA). The exclusion criteria were as follows: (1) comorbid Moyamoya disease, (2) acute carotid artery occlusion. Clinical Data The following information was collected from patients with CMAD: patient demographics (age, sex), medical history (hypertension, type II diabetes, coronary heart disease, ischemic stroke, smoking, alcohol consumption), aneurysm characteristics (number, size and location), and internal carotid artery occlusion side (left, right, bilateral). Statistical Analysis Normally distributed continuous data are presented as the mean ± standard deviation (SD). When a patient has multiple aneurysms, ruptured aneurysms are classified according to the responsible aneurysm, while unruptured aneurysms are classified based on the largest aneurysm. We use logistic regression to identify risk factors for the rupture of UIA combined with ICAO in patients. In the univariate analysis, variables with p < 0.05 were entered into the multivariate analysis. We performed multivariable backward stepwise logistic regression analysis to identify independent factors associated with subarachnoid hemorrhage. Statistical analyses were performed using SPSS software (version 27.0, SPSS IBM), and a P-value < 0.05 was considered statistically significant. Results Patient Characteristics Table 1 :Baseline Characteristics of Intracranial Aneurysms with ICAO and Subgroups for Comparing Patients with RIA and UIA. Among 11,686 IA patients, 281 patients with ICAO. After excluding 181 Moyamoya disease patients and 7 with acute internal carotid artery occlusion, 93 (0.8%) patients were included in the study. The study cohort consisted of 55 males and 38 females, with an average age of 60.7 ± 9.5years. This encompassed 52 cases of RIAs and 41 cases of UIAs. We found that 81 patients had unilateral ICAO, while 12 had bilateral ICAO. Among those with unilateral ICAO, aneurysms were located ipsilaterally in 16 patients, along the midline in 22 patients, and contralaterally in 43 patients. The 93 patients in our study had a total of 115 intracranial aneurysms, with 76 presenting a single aneurysm and 17 presenting multiple aneurysms. In patients with unilateral ICAO, a total of 99 aneurysms were identified: 21 aneurysms were located on the same side as the occluded carotid artery, 53 on the opposite side, and 25 along the midline (14 in the anterior communicating artery and 11 at the tip of the basilar artery). In patients with bilateral ICAO, 16 aneurysms were found, with 4 located in the anterior circulation and 12 in the posterior circulation. Table 1 Baseline Characteristics of Intracranial Aneurysms with ICAO and Subgroups for Comparing Patients with RIA and UIA Characteristic All(n = 93) RIA(n = 52) UIA(n = 41) P value Sex 0.456 male 55(59.1%) 29(55.8%) 26(63.4%) female 38(40.9%) 23(44.2%) 15(36.6%) Age, year 60.7 ± 9.5y 61.3 ± 9.1y 60.0 ± 10.1y 0.158 <65 56(60.2%) 28(53.8%) 28(68.3%) ≥ 65 37(39.8%) 24(46.2%) 13(31.7%) Medical history Hypertension(yes) 55(59.1%) 33(63.5%) 22(53.7%) 0.340 Type II diabetes(yes) 12(12.9%) 8(15.4%) 4(9.8%) 0.421 Ischemic stroke(yes) 18(19.4%) 9(17.3%) 9(22.0%) 0.574 Smoking(yes) 25(26.9%) 15(28.8%) 10(24.4) 0.630 Alcohol consumption(yes) 11(11.8%) 7(13.5%) 4(9.8%) 0.583 Coronary heart disease(yes) 13(14.0%) 7(13.5%) 6(14.6%) 0.871 Number of ICAO 0.008 Unilateral 81(87.1%) 41(78.8%) 40(97.6%) Bilateral 12(12.9%) 11(21.2%) 1(2.4%) Number of aneurysms 0.178 Single aneurysm 76(81.7%) 40(76.9%) 36(87.8%) Multiple aneurysms 17(18.3%) 12(23.1%) 5(12.2%) Aneurysms site 0.001 ACA/AcomA 21(48.8%) 14(26.9%) 7(17.1%) MCA 1(1.1%) 0(0%) 1(2.4%) PcomA 16(17.2%) 7(13.5%) 9(21.95%) ICA 19(20.4%) 4(7.7%) 15(36.6%) Posterior circulation 36(38.7%) 27(51.9%) 9(21.95%) Aneurysm size 0.491 <5mm 53(57%) 28(53.8%) 25(61%) ≥ 5mm 40(43%) 24(46.2%) 16(39%) Abbreviations: ACA, anterior cerebral artery; AcomA, anterior communicating artery; ICA, internal cerebral artery;MCA,middle cerebral artery; PcomA, posterior communicating artery. Table 2 Frequency of Posterior Circulation Aneurysms in RIA and UIA Patients Posterior circulation aneurysms All(n = 36) RIA(n = 27) UIA(n = 9) BA 16(44.4%) 14(51.9%) 2(22.2%) PCA 13(36.1%) 9(33.3%) 4(44.4%) SCA 1(2.8%) 1(3.7%) 0(0) PICA 3(8.3%) 2(7.4%) 1(11.1%) VA 3(8.3%) 1(3.7%) 2(22.2%) Abbreviations: BA, basilar artery ;SCA,superior cerebellar artery; AICA,anterior inferior cerebellar artery ;PICA,posterior inferior cerebellar artery;VA,vertebral artery. Table 3 :The distribution frequencies of the relationship between ICAO lateralization and intracranial aneurysm location between the two groups. After excluding 12 patients with bilateral internal carotid artery occlusion, a comparison was made among 81 patients with unilateral internal carotid artery occlusion to assess the relationship between the side of internal carotid artery occlusion and the location of intracranial aneurysms. A chi-square test indicated a statistically significant difference between the two groups(p = 0.009). Table 3 Comparison of the relationship between aneurysm location and side of ICAO between the RIA and UIA groups Groups All(n = 81) RIA(n = 41) UIA(n = 40) Ipsilateral 16(19.8%) 8(19.5%) 8(20.0%) Contralateral 43(53.1%) 16(39.0%) 27(67.5%) Midline 22(27.2%) 17(41.5%) 5(12.5%) P value 0.009 Table 4 : Comparison of arterial aneurysm location between unilateral ICAO and bilateral ICAO. Merging unilateral and bilateral internal carotid artery occlusions for intracranial aneurysm location grouping revealed a significant statistical difference(p < 0.001). Bilateral occlusions are more prone to posterior circulation aneurysms. Table 4 Comparison of arterial aneurysm location between unilateral ICAO and bilateral ICAO. Groups All(n = 93) Anterior circulation aneurysm(n = 57) Posterior circulation aneurysm(n = 36) Unilateral occlusion 81(87.1%) 55(67.9%) 26(32.1%) Bilateral occlusion 12(12.9%) 2(16.7%) 10(83.3%) P value <0.001 Risk factors for ICAO combined with UIA rupture Results of a univariable and multivariable analysis of factors related to ICAO combined with UIA rupture in patient are summarized in Table 5 . The statistical results showed that the following variables were associated with aneurysm rupture based on the univariable analysis: Bilateral internal carotid artery occlusion (HR 10.732; 1.323–87.021 95% CI; P = 0.026), posterior circulation aneurysms (HR 3.84; 1.533–9.617 95% CI; P = 0.004). Further multivariable analysis revealed that posterior circulation aneurysms (HR 2.874; 1.101–7.497 95% CI; P = 0.031) were an independent risk factor for UIA rupture combined with ICAO. Although hypertension is not a risk factor for UIA rupture combined with ICAO in the multivariable regression analysis, further analysis of the hypertensive patient group reveals that uncontrolled blood pressure control increases the risk of aneurysm rupture. See supplementary materials for details. Table 5 Risk factors associated with rupture: Univariable and multivariable analysis Characteristics Univariate Multivariate HR 95% CI P value HR 95% CI P value Sex(fmale) 1.375 0.265–2.087 0.457 — — — Age(≥ 65y) 1.846 0.786–4.338 0.160 — — — Medical history Hypertension(Yes) 1.500 0.652–3.453 0.341 — — — Type II diabetes(Yes) 1.682 0.469–6.033 0.425 — — — Ischemic stroke(Yes) 0.744 0.265–2.087 0.574 — — — Smoking(Yes) 1.257 0.495–3.191 0.631 — — — Alcohol consumption(Yes) 1.439 0.391–5.297 0.584 — — — Coronary heart disease(Yes) 0.907 0.280–2.943 0.871 — — — Occlusion number Single 1 Reference — 1 Reference — Double 10.732 1.323–87.021 0.026 6.663 0.778–57.097 0.084 Location of aneurysm Anterior circulation 1 Reference — 1 Reference — Posterior circulation 3.84 1.533–9.617 0.004 2.874 1.101–7.497 0.031 Number of aneurysm Single aneurysm 1 Reference — — — — Multiple aneurysms 2.160 0.693–6.729 0.184 — — — Aneurysm size <5mm 1 Reference — — — — ≥ 5mm 1.339 0.583–3.075 0.491 — — — Discussion We conducted a comprehensive study on 93 patients with cerebral aneurysms and concurrent internal carotid artery occlusion to investigate their clinical characteristics and risk factors influencing aneurysm rupture. To our knowledge, this is the largest multicenter study to date on intracranial aneurysms in the setting of internal carotid artery occlusion. The main aim of our study was to gain a deeper understanding of the clinical features associated with this rare condition and analyze the impact of various risk factors on the risk of rupture of unruptured intracranial aneurysms in the context of concurrent internal carotid artery occlusion. Baseline Characteristics of Patients with ICAO combined with intracranial aneurysms The formation mechanism of intracranial aneurysms primarily involves abnormal hemodynamic changes triggered by anatomical variations and pathological conditions, as well as the biomechanical interaction of the arterial wall [ 20 ] . The Circle of Willis, as an important bridge and flow regulator of intracranial vascular connections, is crucial for maintaining stable cerebral circulation [ 21 ] . However, due to structural abnormalities of cerebral vessels, especially congenital variations in the region of the Circle of Willis, changes in intracranial hemodynamics may occur, leading to the formation of intracranial aneurysms [ 22 , 23 ] . A study by Shakur et al. [ 24 ] revealed that patients with concurrent internal carotid artery occlusion and intracranial aneurysms exhibit a significant increase in blood flow velocity and wall shear stress in the anterior communicating artery. Furthermore, new or enlarged aneurysms are frequently observed on collateral vessels following internal carotid artery occlusion. This study revealed that the majority of intracranial aneurysms associated with concurrent internal carotid artery occlusion are located on the contralateral collateral circulation and midline, particularly in regions with higher hemodynamic loads such as the anterior communicating artery, posterior communicating artery, basilar artery, and the junction of the basilar artery and posterior cerebral artery. The higher incidence of intracranial aneurysms in the anterior communicating artery and posterior communicating artery is also attributed to compensatory changes in the cerebral Willis circle following internal carotid artery occlusion, with these arteries being considered as the primary collateral pathways after internal carotid artery occlusion [ 25 , 26 ] . The majority of the literature on the coexistence of ICAO and intracranial aneurysms is derived from prospective studies investigating aneurysm formation, growth, and rupture post internal carotid artery ligation, as well as isolated case reports. These aneurysms predominantly affect the anterior communicating artery and posterior communicating artery.In the study conducted by Crobeddu et al., it was found that the majority of intracranial aneurysms in patients with concomitant internal carotid artery occlusion were located in the anterior communicating artery, with a lower incidence observed in the posterior circulation [ 27 ] .Nevertheless, our retrospective study using CMAD demonstrated a notable association between internal carotid artery occlusion and concomitant posterior circulation aneurysms. The incidence of posterior circulation aneurysms was found to be 38.7%, with a strikingly higher rate of 51.9% observed in cases of ruptured aneurysms. This incidence far surpasses the occurrence rate of posterior circulation aneurysms in the absence of concurrent ICAO [ 28 , 29 ] . Furthermore, animal experiments conducted by Gao L et al. [ 30 ] indicated that after carotid artery ligation, there was a significant increase in the maximum blood flow velocity in the basilar artery by 105–900%. All rabbits subjected to carotid artery ligation developed de novo aneurysms, characterized by a bulging near the terminal segment of the basilar artery, thinning of the media, and absence of the internal elastic lamina. These findings are consistent with the results of our study. Our study revealed that in patients with intracranial aneurysms and concurrent unilateral ICAO, aneurysms were more frequently located on the contralateral side and in the midline position of the ICAO. Additionally, our comparison between unilateral and bilateral internal carotid artery occlusions demonstrated a higher propensity for developing posterior circulation aneurysms in cases of bilateral occlusion. These findings collectively suggest that the establishment of major collateral circulation and hemodynamic alterations following internal carotid artery occlusion may play a critical role in the pathogenesis and progression of cerebral aneurysms. Risk factors for ICAO combined with UIA rupture In past and current research, it has been found that the location of an aneurysm is a significant risk factor for its rupture [ 13 , 16 , 18 ] . Aneurysms in the posterior circulation are believed to be associated with a higher risk of rupture [ 16 , 31 , 32 , 33 ] . In our study, aneurysms located in the posterior circulation were identified as an independent risk factor for the rupture of UIA in patients with concurrent ICAO, consistent with previous research findings. Currently, there are numerous predictive models for assessing the rupture risk of UIA [ 34 – 36 ] . In terms of intracranial aneurysm characteristics, our study results suggest that the location of the aneurysm may be a more critical parameter to consider in stratifying rupture risk. Investigating such cases contributes to a better understanding of the pivotal role of hemodynamic alterations in the processes of aneurysm formation, growth, and rupture. In the presence of internal carotid artery occlusion, the vertebral-basilar system can compensate for cerebral blood supply through collateral circulation pathways, such as the posterior communicating artery. The increased vulnerability to rupture and hemorrhage in posterior circulation aneurysms, particularly those located in the basilar artery, in the context of internal carotid artery occlusion, can be elucidated by both hemodynamic and anatomical factors.Primarily, the risk of formation and rupture of vertebral-basilar artery aneurysms may be related to the direction of blood flow perpendicular to the inflow direction of the aneurysm [ 37 ] . Additionally, despite the similar appearance of the fully developed anatomy of the vertebral-basilar arteries and the internal carotid arteries, their embryonic origins are entirely distinct. The vertebral-basilar arteries are derived from the fusion of two longitudinal neural arteries, whereas the internal carotid arteries originate directly from a single vessel (the third aortic arch) [ 38 ] .These factors may render the vertebral-basilar arteries more susceptible to hemodynamic alterations caused by ICAO, potentially resulting in a greater likelihood of rapid growth and rupture of posterior circulation aneurysms as opposed to anterior circulation aneurysms. Nonetheless, the precise underlying mechanisms remain elusive, warranting further investigation to elucidate this phenomenon. Previous studies have also revealed a higher mortality rate associated with posterior circulation aneurysms compared to anterior circulation aneurysms [ 39 – 42 ] . Therefore, when treating posterior circulation aneurysms concomitant with internal carotid artery occlusion, it is imperative to carefully select treatment modalities and closely monitor the risk of rupture. Further research is needed to elucidate the specific mechanisms, enhance treatment decision-making, and prevent rupture. Numerous studies have highlighted age as a critical risk factor for aneurysm rupture, with the risk escalating as individuals grow older [ 13 , 43 , 44 ] . Although this study indicates that age may not be an independent risk factor for the rupture of UIA in the presence of concomitant ICAO, statistical analysis reveals a positive association between increasing age and the risk of aneurysm rupture, aligning with previous research findings. While hemodynamic and anatomical characteristics play a crucial role in the formation and rupture of aneurysms, environmental factors also contribute significantly. Factors such as smoking history, multiple aneurysms, and hypertension have been established as independent risk factors for rupture in other studies [ 45 – 49 ] . However, in our cohort, these factors did not show a significant impact on aneurysm rupture. Furthermore, the size and shape of an aneurysm play a critical role in assessing the risk of rupture in UIA. Larger aneurysms and irregular shapes are often associated with a higher risk of rupture. Therefore, a comprehensive assessment of the risk of aneurysm rupture should take into account hemodynamic, anatomical, and environmental factors. Limitations This study has some limitations. Firstly, the study design is retrospective, which may introduce information retrieval biases and issues with incomplete data. Future research should consider using prospective study designs to address these limitations. Secondly, the sample size of this study is relatively small, which may limit the statistical power and generalizability of the study findings. Future studies should include larger and more diverse samples to enhance the robustness of these results. Thirdly, during our research process, we overlooked the impact of anatomical variations in the Willis circle on cerebral hemodynamics. This oversight may have led to an exaggerated emphasis on the influence of changes in cerebral hemodynamics following internal carotid artery occlusion on the development and rupture of intracranial aneurysms. In future research, revising the study plan, collecting new data, or employing novel analytical methods may be necessary to analyze how variations in Willis circle anatomy combined with ICAO impact the formation and rupture of intracranial aneurysms. Conclusion We conducted a comprehensive retrospective analysis to investigate the clinical characteristics of intracranial aneurysms associated with ICAO and identify key factors that may increase the risk of rupture in UIA. Our study found that aneurysm location, particularly in the posterior circulation, is a significant risk factor for rupture in UIA associated with ICAO. Furthermore, we identified a notable association between ICAO and an increased risk of aneurysmal rupture. This highlights the importance of not only focusing on the ischemic stroke risks associated with ICAO but also considering the hemodynamic changes caused by ICAO that may contribute to the risk of aneurysm rupture. This provides valuable insights for the management of ICAO. Declarations • Ethics approval and consent to participate Human Ethics and Consent to Participate declarations: not applicable. • Availability of data and materials The datasets generated and/or analysed during the current study are not publicly available due [REASON WHY DATA ARE NOT PUBLIC] but are available from the corresponding author on reasonable request. • Competing interests The authors declare that they have no competing interests • Funding No funding. • Acknowledgements Not applicable. References Vlak MH, Algra A, Brandenburg R, Rinkel GJ. Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: a systematic review and meta-analysis. 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Backes D, Rinkel GJE, Greving JP, Velthuis BK, Murayama Y, Takao H, Ishibashi T, Igase M, terBrugge KG, Agid R, Jääskeläinen JE, Lindgren AE, Koivisto T, von Und Zu Fraunberg M, Matsubara S, Moroi J, Wong GKC, Abrigo JM, Igase K, Matsumoto K, Wermer MJH, van Walderveen MAA, Algra A, Vergouwen MDI. ELAPSS score for prediction of risk of growth of unruptured intracranial aneurysms. Neurology. 2017 Apr 25;88(17):1600-1606. De Rooij NK, Velthuis BK, Algra A, Rinkel GJE: Configuration of the circle of Willis, direction of flow, and shape of the aneurysm as risk factors for rupture of intracranial aneurysms. J Neurol 2009;256:45–50. Okahara M, Kiyosue H, Mori H, Tanoue S, Sainou M, Nagatomi H: Anatomical variations of the cerebral arteries and their embryology: a pictorial review. Eur J Radiol 2001;12:2548–2561. Rice BJ, Peerless SJ, Drake CG. Surgical treatment of unruptured aneurysms of the posterior circulation. J Neurosurg. 1990;73:165–73. Eskridge JM, Song JK. Endovascular embolization of 150 basilar tip aneurysms with Guglielmi detachable coils: results of the Food and Drug Administration multicenter clinical trial. J Neurosurg. 1998;89:81–6. Peerless SJ, Hernesniemi JA, Gutman FB, Drake CG. Early surgery for ruptured vertebrobasilar aneurysms. J Neurosurg. 1994;80:643–9. Raaymakers TW, Rinkel GJ, Limburg M, Algra A. Mortality and morbidity of surgery for unruptured intracranial aneurysms: a meta-analysis. Stroke. 1998;29:1531–8. Kawada T, Hishikawa T, Date I, Tominari S, Morita A. Risk of rupture of unruptured cerebral aneurysms in elderly patients. Neurology. 2016 Apr 26;86(17):1650. Juvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg. 2000 Sep;93(3):379-87. Juvela S. Natural history of unruptured intracranial aneurysms: risks for aneurysm formation, growth, and rupture. Acta Neurochir Suppl. 2002;82:27-30 Sonobe M, Yamazaki T, Yonekura M, Kikuchi H. Small Unruptured Intracranial Aneurysm Verification Study: SUAVe Study, Japan. Stroke 2010;41:1969-77. Juvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg 2000;93:379-87. Yasui N, Suzuki A, Nishimura H, Suzuki K, Abe T. Long-term follow-up study of unruptured intracranial aneurysms. Neurosurgery 1997;40:1155-9. Brown RD Jr, Huston J, Hornung R, et al. Screening for brain aneurysm in the Familial Intracranial Aneurysm study: frequency and predictors of lesion detection. J Neurosurg.2008;108(6):1132-1138. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 13 Aug, 2025 Read the published version in BMC Neurology → Version 1 posted Editorial decision: Revision requested 05 Apr, 2025 Reviews received at journal 31 Mar, 2025 Reviews received at journal 26 Mar, 2025 Reviewers agreed at journal 18 Mar, 2025 Reviewers agreed at journal 17 Mar, 2025 Reviewers invited by journal 02 Sep, 2024 Editor invited by journal 25 Jul, 2024 Editor assigned by journal 25 Jul, 2024 Submission checks completed at journal 25 Jul, 2024 First submitted to journal 24 Jul, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4793934","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":341761440,"identity":"bace9555-e356-4b06-aaf2-e4862d33e550","order_by":0,"name":"Pengran Liu","email":"","orcid":"","institution":"Tianjin Medical University General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Pengran","middleName":"","lastName":"Liu","suffix":""},{"id":341761441,"identity":"5e7a7f30-0456-48f7-af61-14e84cf7859c","order_by":1,"name":"Bangyue Wang","email":"","orcid":"","institution":"Tianjin Medical University General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Bangyue","middleName":"","lastName":"Wang","suffix":""},{"id":341761442,"identity":"850a09d9-3d24-46ce-b872-2ef979cf4019","order_by":2,"name":"Jing Guo","email":"","orcid":"","institution":"The Second People’s Hospital Of Mudanjaing City","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Guo","suffix":""},{"id":341761443,"identity":"f533dc87-e3b1-4995-963c-6441cd9ef58f","order_by":3,"name":"Hui Dai","email":"","orcid":"","institution":"Tianyou Hospital","correspondingAuthor":false,"prefix":"","firstName":"Hui","middleName":"","lastName":"Dai","suffix":""},{"id":341761444,"identity":"7504fe2c-2557-47aa-9cce-e841a286f3f8","order_by":4,"name":"Yan Zhao","email":"","orcid":"","institution":"Tianjin Medical University General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Zhao","suffix":""},{"id":341761445,"identity":"5c948195-b9b4-4480-b846-3248cc5c0568","order_by":5,"name":"Wentao Dong","email":"","orcid":"","institution":"Affiliated Jinhua Hospital","correspondingAuthor":false,"prefix":"","firstName":"Wentao","middleName":"","lastName":"Dong","suffix":""},{"id":341761446,"identity":"f9a5fa7c-c574-4d89-8826-0ae16e1d3724","order_by":6,"name":"Shujie Liu","email":"","orcid":"","institution":"The Second People’s Hospital Of Mudanjaing City","correspondingAuthor":false,"prefix":"","firstName":"Shujie","middleName":"","lastName":"Liu","suffix":""},{"id":341761447,"identity":"2ca11de0-b1e7-43c4-a91c-d09c29a352ae","order_by":7,"name":"Xinyu Yang","email":"","orcid":"","institution":"Tianjin Medical University General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xinyu","middleName":"","lastName":"Yang","suffix":""},{"id":341761448,"identity":"176347f1-285a-48fc-8e32-e1f44797b9d4","order_by":8,"name":"Xiaojun Zhang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA50lEQVRIie3RMYvCMBTA8VcCmWKzpije5lwRnMTPklLIVMGxg0NB0cEWHfsxHB0jgbhEZ8eKX+DkFqfjOFfF1M0hv/n9SV4C4DgfCNPp/udG2JDS1bXi6cSe+EwLBK1BHJSyF1ZG25M2JB0EA+FtJO8H5xmqcTEw+DJOFAqlFGmUYaCLJX+doGLfK43yA5XpU7RtATOHjeWUI2eNXCFf7uanyGAI2ciWJCFr/CovkzEeR3NUK+k3CRHeWgoM9RKm425J/h/ZIMaNJtZdvlbTXfV9/8rcu97SSZsuitfJA/LeuOM4jvPUHxasTCNZI8F7AAAAAElFTkSuQmCC","orcid":"","institution":"Tianyou Hospital","correspondingAuthor":true,"prefix":"","firstName":"Xiaojun","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2024-07-24 09:06:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4793934/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4793934/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12883-025-04362-7","type":"published","date":"2025-08-13T15:57:41+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89310656,"identity":"8f17d11c-2f4c-4594-9cb8-0bde514a8964","added_by":"auto","created_at":"2025-08-18 16:09:13","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":858651,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4793934/v1/3c13bd84-f81d-4643-89f9-8c0358925c90.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Intracranial Aneurysm Location: Key Factor in Ruptures with Internal Carotid Artery Occlusion","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAmong the general population, the prevalence rate of unruptured intracranial aneurysm1 (UIA) is approximately 3.2%\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e, the annual risk of Subarachnoid hemorrhage (SAH) from UIA is about 1%\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. SAH is an extremely serious and potentially fatal condition, with a high mortality and disability rate, most cases of non-traumatic SAH are attributed to the rupture of intracranial aneurysms\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. With the widespread use of non-invasive imaging techniques, an increasing number of patients with spontaneous internal carotid artery occlusion (ICAO) are found to have intracranial aneurysms. ICAO is a relatively common cause of stroke and transient ischemic attacks (TIAs), accounting for about 10\u0026ndash;15% of all cases\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Therefore, it is believed that the presence of both conditions can elevate the risk of mortality and morbidity even when collateral circulation is adequate. These conditions are more common in older patients who often have significant comorbidities and advanced atherosclerosis. The management of IAs in the presence of ICAO poses a considerable challenge for neurosurgeons due to the potential treatment risks and high rupture probability. Current literature on IAs with ICAO is largelyanecdotal\u003csup\u003e[\u003cspan additionalcitationids=\"CR9 CR10 CR11\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e, lacking definitive guidelines and consensus for optimal patient management.\u003c/p\u003e \u003cp\u003eExisting research has pinpointed potential risk factors for intracranial aneurysm rupture, including size, location, multiplicity, shape, smoking, age, hypertension, hypercholesterolemia, and a history ofSAH\u003csup\u003e[\u003cspan additionalcitationids=\"CR14 CR15 CR16 CR17\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. Yet, data on rupture risks for UIAs in the context of ICAO remain unreported.\u003c/p\u003e \u003cp\u003eOur research is dedicated to exploring the clinical characteristics and risk factors influencing the rupture of intracranial aneurysms associated with ICAO. This exploration aims to deepen our understanding of the causes behind the rupture of IAs in the context of ICAO and to enhance the treatment strategies and prognosis for such conditions.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients Data\u003c/h2\u003e \u003cp\u003eThis study used data from the Chinese Multicenter Aneurysm Database (CMAD) (website: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.cmadtj.com\u003c/span\u003e\u003cspan address=\"http://www.cmadtj.com\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e; clinical trial No.:ChiCTR2200065083). CMAD is a multicenter research project registered in China, led by Tianjin Medical University General Hospital. The collaborating centers, located in Tianjin, Hebei, Shandong, and Shanxi, have collectively registered over 10,000 cases of cerebral aneurysms. The CMAD data is sourced from medical records. This study was approved by the Ethics Committee of the Tianjin Medical University General Hospital (IRB2021-YX-178-01) and registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2100054014). All the procedures were performed in accordance with the World Medical Association Declaration of Helsinki\u003csup\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e. After being approved, we cross-searched CMAD of patients combining the terms \u0026ldquo;intracranial aneurysms\u0026rdquo; and \u0026ldquo;internal carotid artery occlusion.\u0026rdquo; The inclusion criteria were as follows: diagnosis of aneurysms with spontaneous occlusion of the internal carotid artery confirmed by at least one examination\u0026mdash;computed tomography angiography (CTA), magnetic resonance angiography (MRA), or digital subtraction angiography (DSA). The exclusion criteria were as follows: (1) comorbid Moyamoya disease, (2) acute carotid artery occlusion.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eClinical Data\u003c/h2\u003e \u003cp\u003eThe following information was collected from patients with CMAD: patient demographics (age, sex), medical history (hypertension, type II diabetes, coronary heart disease, ischemic stroke, smoking, alcohol consumption), aneurysm characteristics (number, size and location), and internal carotid artery occlusion side (left, right, bilateral).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eNormally distributed continuous data are presented as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD). When a patient has multiple aneurysms, ruptured aneurysms are classified according to the responsible aneurysm, while unruptured aneurysms are classified based on the largest aneurysm. We use logistic regression to identify risk factors for the rupture of UIA combined with ICAO in patients. In the univariate analysis, variables with p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were entered into the multivariate analysis. We performed multivariable backward stepwise logistic regression analysis to identify independent factors associated with subarachnoid hemorrhage. Statistical analyses were performed using SPSS software (version 27.0, SPSS IBM), and a P-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\"\u003e\n \u003ch2\u003ePatient Characteristics\u003c/h2\u003e\n \u003cp\u003eTable\u0026nbsp;\u003cspan\u003e1\u003c/span\u003e:Baseline Characteristics of Intracranial Aneurysms with ICAO and Subgroups for Comparing Patients with RIA and UIA. Among 11,686 IA patients, 281 patients with ICAO. After excluding 181 Moyamoya disease patients and 7 with acute internal carotid artery occlusion, 93 (0.8%) patients were included in the study. The study cohort consisted of 55 males and 38 females, with an average age of 60.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.5years. This encompassed 52 cases of RIAs and 41 cases of UIAs. We found that 81 patients had unilateral ICAO, while 12 had bilateral ICAO. Among those with unilateral ICAO, aneurysms were located ipsilaterally in 16 patients, along the midline in 22 patients, and contralaterally in 43 patients. The 93 patients in our study had a total of 115 intracranial aneurysms, with 76 presenting a single aneurysm and 17 presenting multiple aneurysms. In patients with unilateral ICAO, a total of 99 aneurysms were identified: 21 aneurysms were located on the same side as the occluded carotid artery, 53 on the opposite side, and 25 along the midline (14 in the anterior communicating artery and 11 at the tip of the basilar artery). In patients with bilateral ICAO, 16 aneurysms were found, with 4 located in the anterior circulation and 12 in the posterior circulation.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 1\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eBaseline Characteristics of Intracranial Aneurysms with ICAO and Subgroups for Comparing Patients with RIA and UIA\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCharacteristic\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll(n\u0026thinsp;=\u0026thinsp;93)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRIA(n\u0026thinsp;=\u0026thinsp;52)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUIA(n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.456\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003emale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55(59.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29(55.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26(63.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003efemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e38(40.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23(44.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15(36.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge, year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.5y\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.3\u0026thinsp;\u0026plusmn;\u0026thinsp;9.1y\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60.0\u0026thinsp;\u0026plusmn;\u0026thinsp;10.1y\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.158\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e56(60.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28(53.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28(68.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e37(39.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24(46.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13(31.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMedical history\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHypertension(yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55(59.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e33(63.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22(53.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.340\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eType II diabetes(yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12(12.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8(15.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4(9.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.421\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIschemic stroke(yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18(19.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9(17.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9(22.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.574\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSmoking(yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25(26.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15(28.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10(24.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.630\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlcohol consumption(yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11(11.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(13.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4(9.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.583\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCoronary heart disease(yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13(14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(13.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6(14.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.871\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNumber of ICAO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.008\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUnilateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81(87.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e41(78.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40(97.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBilateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12(12.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11(21.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1(2.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNumber of aneurysms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.178\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSingle aneurysm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e76(81.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40(76.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36(87.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMultiple aneurysms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17(18.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12(23.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5(12.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAneurysms site\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eACA/AcomA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21(48.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14(26.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(17.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMCA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1(1.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0(0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1(2.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePcomA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16(17.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(13.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9(21.95%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eICA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19(20.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4(7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15(36.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePosterior circulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e36(38.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27(51.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9(21.95%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAneurysm size\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.491\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;5mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e53(57%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28(53.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e25(61%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;5mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40(43%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24(46.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16(39%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eAbbreviations: ACA, anterior cerebral artery; AcomA, anterior communicating artery; ICA, internal cerebral artery;MCA,middle cerebral artery; PcomA, posterior communicating artery.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab2\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 2\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eFrequency of Posterior Circulation Aneurysms in RIA and UIA Patients\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePosterior circulation aneurysms\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll(n\u0026thinsp;=\u0026thinsp;36)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRIA(n\u0026thinsp;=\u0026thinsp;27)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUIA(n\u0026thinsp;=\u0026thinsp;9)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16(44.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14(51.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2(22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePCA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13(36.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9(33.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4(44.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSCA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1(2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1(3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0(0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePICA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3(8.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2(7.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1(11.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eVA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3(8.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1(3.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2(22.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\"\u003eAbbreviations: BA, basilar artery ;SCA,superior cerebellar artery; AICA,anterior inferior cerebellar artery ;PICA,posterior inferior cerebellar artery;VA,vertebral artery.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eTable \u003cspan\u003e3\u003c/span\u003e:The distribution frequencies of the relationship between ICAO lateralization and intracranial aneurysm location between the two groups. After excluding 12 patients with bilateral internal carotid artery occlusion, a comparison was made among 81 patients with unilateral internal carotid artery occlusion to assess the relationship between the side of internal carotid artery occlusion and the location of intracranial aneurysms. A chi-square test indicated a statistically significant difference between the two groups(p\u0026thinsp;=\u0026thinsp;0.009).\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eComparison of the relationship between aneurysm location and side of ICAO between the RIA and UIA groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGroups\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll(n\u0026thinsp;=\u0026thinsp;81)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRIA(n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUIA(n\u0026thinsp;=\u0026thinsp;40)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIpsilateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16(19.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8(19.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8(20.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eContralateral\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e43(53.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16(39.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e27(67.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMidline\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22(27.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17(41.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5(12.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e0.009\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eTable\u0026nbsp;\u003cspan\u003e4\u003c/span\u003e: Comparison of arterial aneurysm location between unilateral ICAO and bilateral ICAO. Merging unilateral and bilateral internal carotid artery occlusions for intracranial aneurysm location grouping revealed a significant statistical difference(p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Bilateral occlusions are more prone to posterior circulation aneurysms.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab4\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 4\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eComparison of arterial aneurysm location between unilateral ICAO and bilateral ICAO.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eGroups\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAll(n\u0026thinsp;=\u0026thinsp;93)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eAnterior circulation aneurysm(n\u0026thinsp;=\u0026thinsp;57)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ePosterior circulation aneurysm(n\u0026thinsp;=\u0026thinsp;36)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUnilateral occlusion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e81(87.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55(67.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e26(32.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBilateral occlusion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12(12.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2(16.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10(83.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\"\u003e\n \u003ch2\u003eRisk factors for ICAO combined with UIA rupture\u003c/h2\u003e\n \u003cp\u003eResults of a univariable and multivariable analysis of factors related to ICAO combined with UIA rupture in patient are summarized in Table \u003cspan\u003e5\u003c/span\u003e. The statistical results showed that the following variables were associated with aneurysm rupture based on the univariable analysis: Bilateral internal carotid artery occlusion (HR 10.732; 1.323\u0026ndash;87.021 95% CI; P\u0026thinsp;=\u0026thinsp;0.026), posterior circulation aneurysms (HR 3.84; 1.533\u0026ndash;9.617 95% CI; P\u0026thinsp;=\u0026thinsp;0.004). Further multivariable analysis revealed that posterior circulation aneurysms (HR 2.874; 1.101\u0026ndash;7.497 95% CI; P\u0026thinsp;=\u0026thinsp;0.031) were an independent risk factor for UIA rupture combined with ICAO. Although hypertension is not a risk factor for UIA rupture combined with ICAO in the multivariable regression analysis, further analysis of the hypertensive patient group reveals that uncontrolled blood pressure control increases the risk of aneurysm rupture. See supplementary materials for details.\u003c/p\u003e\n \u003cdiv\u003e\n \u003ctable id=\"Tab5\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 5\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eRisk factors associated with rupture: Univariable and multivariable analysis\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"7\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eUnivariate\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eMultivariate\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSex(fmale)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.375\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.265\u0026ndash;2.087\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.457\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAge(\u0026ge;\u0026thinsp;65y)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.846\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.786\u0026ndash;4.338\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"7\"\u003e\n \u003cp\u003eMedical history\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHypertension(Yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.500\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.652\u0026ndash;3.453\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.341\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eType II diabetes(Yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.682\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.469\u0026ndash;6.033\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.425\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIschemic stroke(Yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.744\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.265\u0026ndash;2.087\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.574\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSmoking(Yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.257\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.495\u0026ndash;3.191\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.631\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAlcohol consumption(Yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.439\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.391\u0026ndash;5.297\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.584\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCoronary heart disease(Yes)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.907\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.280\u0026ndash;2.943\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.871\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"7\"\u003e\n \u003cp\u003eOcclusion number\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSingle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDouble\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.732\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.323\u0026ndash;87.021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.026\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.663\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.778\u0026ndash;57.097\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.084\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colspan=\"7\"\u003e\n \u003cp\u003eLocation of aneurysm\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAnterior circulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePosterior circulation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.84\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.533\u0026ndash;9.617\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.874\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.101\u0026ndash;7.497\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.031\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNumber of aneurysm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSingle aneurysm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMultiple aneurysms\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.693\u0026ndash;6.729\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.184\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAneurysm size\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026lt;5mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026ge;\u0026thinsp;5mm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.339\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.583\u0026ndash;3.075\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.491\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u0026mdash;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe conducted a comprehensive study on 93 patients with cerebral aneurysms and concurrent internal carotid artery occlusion to investigate their clinical characteristics and risk factors influencing aneurysm rupture. To our knowledge, this is the largest multicenter study to date on intracranial aneurysms in the setting of internal carotid artery occlusion. The main aim of our study was to gain a deeper understanding of the clinical features associated with this rare condition and analyze the impact of various risk factors on the risk of rupture of unruptured intracranial aneurysms in the context of concurrent internal carotid artery occlusion.\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eBaseline Characteristics of Patients with ICAO combined with intracranial aneurysms\u003c/h2\u003e \u003cp\u003eThe formation mechanism of intracranial aneurysms primarily involves abnormal hemodynamic changes triggered by anatomical variations and pathological conditions, as well as the biomechanical interaction of the arterial wall\u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/sup\u003e. The Circle of Willis, as an important bridge and flow regulator of intracranial vascular connections, is crucial for maintaining stable cerebral circulation \u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e. However, due to structural abnormalities of cerebral vessels, especially congenital variations in the region of the Circle of Willis, changes in intracranial hemodynamics may occur, leading to the formation of intracranial aneurysms \u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]\u003c/sup\u003e. A study by Shakur et al.\u003csup\u003e[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/sup\u003e revealed that patients with concurrent internal carotid artery occlusion and intracranial aneurysms exhibit a significant increase in blood flow velocity and wall shear stress in the anterior communicating artery. Furthermore, new or enlarged aneurysms are frequently observed on collateral vessels following internal carotid artery occlusion.\u003c/p\u003e \u003cp\u003eThis study revealed that the majority of intracranial aneurysms associated with concurrent internal carotid artery occlusion are located on the contralateral collateral circulation and midline, particularly in regions with higher hemodynamic loads such as the anterior communicating artery, posterior communicating artery, basilar artery, and the junction of the basilar artery and posterior cerebral artery. The higher incidence of intracranial aneurysms in the anterior communicating artery and posterior communicating artery is also attributed to compensatory changes in the cerebral Willis circle following internal carotid artery occlusion, with these arteries being considered as the primary collateral pathways after internal carotid artery occlusion\u003csup\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe majority of the literature on the coexistence of ICAO and intracranial aneurysms is derived from prospective studies investigating aneurysm formation, growth, and rupture post internal carotid artery ligation, as well as isolated case reports. These aneurysms predominantly affect the anterior communicating artery and posterior communicating artery.In the study conducted by Crobeddu et al., it was found that the majority of intracranial aneurysms in patients with concomitant internal carotid artery occlusion were located in the anterior communicating artery, with a lower incidence observed in the posterior circulation \u003csup\u003e[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e.Nevertheless, our retrospective study using CMAD demonstrated a notable association between internal carotid artery occlusion and concomitant posterior circulation aneurysms. The incidence of posterior circulation aneurysms was found to be 38.7%, with a strikingly higher rate of 51.9% observed in cases of ruptured aneurysms. This incidence far surpasses the occurrence rate of posterior circulation aneurysms in the absence of concurrent ICAO\u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. Furthermore, animal experiments conducted by Gao L et al. \u003csup\u003e[\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e indicated that after carotid artery ligation, there was a significant increase in the maximum blood flow velocity in the basilar artery by 105\u0026ndash;900%. All rabbits subjected to carotid artery ligation developed de novo aneurysms, characterized by a bulging near the terminal segment of the basilar artery, thinning of the media, and absence of the internal elastic lamina. These findings are consistent with the results of our study.\u003c/p\u003e \u003cp\u003eOur study revealed that in patients with intracranial aneurysms and concurrent unilateral ICAO, aneurysms were more frequently located on the contralateral side and in the midline position of the ICAO. Additionally, our comparison between unilateral and bilateral internal carotid artery occlusions demonstrated a higher propensity for developing posterior circulation aneurysms in cases of bilateral occlusion. These findings collectively suggest that the establishment of major collateral circulation and hemodynamic alterations following internal carotid artery occlusion may play a critical role in the pathogenesis and progression of cerebral aneurysms.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eRisk factors for ICAO combined with UIA rupture\u003c/h2\u003e \u003cp\u003eIn past and current research, it has been found that the location of an aneurysm is a significant risk factor for its rupture \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. Aneurysms in the posterior circulation are believed to be associated with a higher risk of rupture\u003csup\u003e[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. In our study, aneurysms located in the posterior circulation were identified as an independent risk factor for the rupture of UIA in patients with concurrent ICAO, consistent with previous research findings. Currently, there are numerous predictive models for assessing the rupture risk of UIA\u003csup\u003e[\u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. In terms of intracranial aneurysm characteristics, our study results suggest that the location of the aneurysm may be a more critical parameter to consider in stratifying rupture risk.\u003c/p\u003e \u003cp\u003eInvestigating such cases contributes to a better understanding of the pivotal role of hemodynamic alterations in the processes of aneurysm formation, growth, and rupture. In the presence of internal carotid artery occlusion, the vertebral-basilar system can compensate for cerebral blood supply through collateral circulation pathways, such as the posterior communicating artery. The increased vulnerability to rupture and hemorrhage in posterior circulation aneurysms, particularly those located in the basilar artery, in the context of internal carotid artery occlusion, can be elucidated by both hemodynamic and anatomical factors.Primarily, the risk of formation and rupture of vertebral-basilar artery aneurysms may be related to the direction of blood flow perpendicular to the inflow direction of the aneurysm \u003csup\u003e[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/sup\u003e. Additionally, despite the similar appearance of the fully developed anatomy of the vertebral-basilar arteries and the internal carotid arteries, their embryonic origins are entirely distinct. The vertebral-basilar arteries are derived from the fusion of two longitudinal neural arteries, whereas the internal carotid arteries originate directly from a single vessel (the third aortic arch) \u003csup\u003e[\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/sup\u003e.These factors may render the vertebral-basilar arteries more susceptible to hemodynamic alterations caused by ICAO, potentially resulting in a greater likelihood of rapid growth and rupture of posterior circulation aneurysms as opposed to anterior circulation aneurysms. Nonetheless, the precise underlying mechanisms remain elusive, warranting further investigation to elucidate this phenomenon. Previous studies have also revealed a higher mortality rate associated with posterior circulation aneurysms compared to anterior circulation aneurysms\u003csup\u003e[\u003cspan additionalcitationids=\"CR40 CR41\" citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003c/sup\u003e. Therefore, when treating posterior circulation aneurysms concomitant with internal carotid artery occlusion, it is imperative to carefully select treatment modalities and closely monitor the risk of rupture. Further research is needed to elucidate the specific mechanisms, enhance treatment decision-making, and prevent rupture.\u003c/p\u003e \u003cp\u003eNumerous studies have highlighted age as a critical risk factor for aneurysm rupture, with the risk escalating as individuals grow older\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]\u003c/sup\u003e. Although this study indicates that age may not be an independent risk factor for the rupture of UIA in the presence of concomitant ICAO, statistical analysis reveals a positive association between increasing age and the risk of aneurysm rupture, aligning with previous research findings.\u003c/p\u003e \u003cp\u003eWhile hemodynamic and anatomical characteristics play a crucial role in the formation and rupture of aneurysms, environmental factors also contribute significantly. Factors such as smoking history, multiple aneurysms, and hypertension have been established as independent risk factors for rupture in other studies\u003csup\u003e[\u003cspan additionalcitationids=\"CR46 CR47 CR48\" citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e]\u003c/sup\u003e. However, in our cohort, these factors did not show a significant impact on aneurysm rupture.\u003c/p\u003e \u003cp\u003eFurthermore, the size and shape of an aneurysm play a critical role in assessing the risk of rupture in UIA. Larger aneurysms and irregular shapes are often associated with a higher risk of rupture. Therefore, a comprehensive assessment of the risk of aneurysm rupture should take into account hemodynamic, anatomical, and environmental factors.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eThis study has some limitations. Firstly, the study design is retrospective, which may introduce information retrieval biases and issues with incomplete data. Future research should consider using prospective study designs to address these limitations. Secondly, the sample size of this study is relatively small, which may limit the statistical power and generalizability of the study findings. Future studies should include larger and more diverse samples to enhance the robustness of these results. Thirdly, during our research process, we overlooked the impact of anatomical variations in the Willis circle on cerebral hemodynamics. This oversight may have led to an exaggerated emphasis on the influence of changes in cerebral hemodynamics following internal carotid artery occlusion on the development and rupture of intracranial aneurysms. In future research, revising the study plan, collecting new data, or employing novel analytical methods may be necessary to analyze how variations in Willis circle anatomy combined with ICAO impact the formation and rupture of intracranial aneurysms.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe conducted a comprehensive retrospective analysis to investigate the clinical characteristics of intracranial aneurysms associated with ICAO and identify key factors that may increase the risk of rupture in UIA. Our study found that aneurysm location, particularly in the posterior circulation, is a significant risk factor for rupture in UIA associated with ICAO. Furthermore, we identified a notable association between ICAO and an increased risk of aneurysmal rupture. This highlights the importance of not only focusing on the ischemic stroke risks associated with ICAO but also considering the hemodynamic changes caused by ICAO that may contribute to the risk of aneurysm rupture. This provides valuable insights for the management of ICAO.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u0026bull; \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHuman Ethics and Consent to Participate declarations: not applicable.\u003c/p\u003e\n\u003cp\u003e\u0026bull; \u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available due [REASON WHY DATA ARE NOT PUBLIC] but are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u0026bull; \u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u0026bull; \u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding.\u003c/p\u003e\n\u003cp\u003e\u0026bull; \u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003cstrong\u003e\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eVlak MH, Algra A, Brandenburg R, Rinkel GJ. 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Anatomical variations in the circle of Willis are associated with increased odds of intracranial aneurysms: The Troms\u0026oslash; study. J Neurol Sci. 2023 Sep 15;452:120740. \u003c/li\u003e\n\u003cli\u003eShakur SF, Alaraj A, Mendoza-Elias N, Osama M, Charbel FT. Hemodynamic characteristics associated with cerebral aneurysm formation in patients with carotid occlusion. J Neurosurg. 2018 May 4;130(3):917-922.\u003c/li\u003e\n\u003cli\u003ePowers WJ. Cerebral hemodynamics in ischemic cerebrovascular disease. Ann Neurol. 1991;29:231\u0026ndash;240.\u003c/li\u003e\n\u003cli\u003eSchomer DF, Marks MP, Steinberg GK, Johnstone IM, Boothroyd DB, Ross MR, Pelc NJ, Enzmann DR. The anatomy of the posterior communicating artery as a risk factor for ischemic cerebral infarction. N Engl J Med. 1994;330:1565\u0026ndash;1570.\u003c/li\u003e\n\u003cli\u003eCrobeddu E, D\u0026apos;Urso PI, Meyer FB, Lanzino G. 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Stroke. 2017 Aug;48(8):2105-2112.\u003c/li\u003e\n\u003cli\u003eBackes D, Rinkel GJE, Greving JP, Velthuis BK, Murayama Y, Takao H, Ishibashi T, Igase M, terBrugge KG, Agid R, J\u0026auml;\u0026auml;skel\u0026auml;inen JE, Lindgren AE, Koivisto T, von Und Zu Fraunberg M, Matsubara S, Moroi J, Wong GKC, Abrigo JM, Igase K, Matsumoto K, Wermer MJH, van Walderveen MAA, Algra A, Vergouwen MDI. ELAPSS score for prediction of risk of growth of unruptured intracranial aneurysms. Neurology. 2017 Apr 25;88(17):1600-1606.\u003c/li\u003e\n\u003cli\u003eDe Rooij NK, Velthuis BK, Algra A, Rinkel GJE: Configuration of the circle of Willis, direction of flow, and shape of the aneurysm as risk factors for rupture of intracranial aneurysms. J Neurol 2009;256:45\u0026ndash;50. \u003c/li\u003e\n\u003cli\u003eOkahara M, Kiyosue H, Mori H, Tanoue S, Sainou M, Nagatomi H: Anatomical variations of the cerebral arteries and their embryology: a pictorial review. Eur J Radiol 2001;12:2548\u0026ndash;2561.\u003c/li\u003e\n\u003cli\u003eRice BJ, Peerless SJ, Drake CG. Surgical treatment of unruptured aneurysms of the posterior circulation. J Neurosurg. 1990;73:165\u0026ndash;73.\u003c/li\u003e\n\u003cli\u003eEskridge JM, Song JK. Endovascular embolization of 150 basilar tip aneurysms with Guglielmi detachable coils: results of the Food and Drug Administration multicenter clinical trial. J Neurosurg. 1998;89:81\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003ePeerless SJ, Hernesniemi JA, Gutman FB, Drake CG. Early surgery for ruptured vertebrobasilar aneurysms. J Neurosurg. 1994;80:643\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eRaaymakers TW, Rinkel GJ, Limburg M, Algra A. Mortality and morbidity of surgery for unruptured intracranial aneurysms: a meta-analysis. Stroke. 1998;29:1531\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eKawada T, Hishikawa T, Date I, Tominari S, Morita A. Risk of rupture of unruptured cerebral aneurysms in elderly patients. Neurology. 2016 Apr 26;86(17):1650. \u003c/li\u003e\n\u003cli\u003eJuvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg. 2000 Sep;93(3):379-87.\u003c/li\u003e\n\u003cli\u003eJuvela S. Natural history of unruptured intracranial aneurysms: risks for aneurysm formation, growth, and rupture. Acta Neurochir Suppl. 2002;82:27-30\u003c/li\u003e\n\u003cli\u003eSonobe M, Yamazaki T, Yonekura M, Kikuchi H. Small Unruptured Intracranial Aneurysm Verification Study: SUAVe Study, Japan. Stroke 2010;41:1969-77.\u003c/li\u003e\n\u003cli\u003eJuvela S, Porras M, Poussa K. Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg 2000;93:379-87.\u003c/li\u003e\n\u003cli\u003eYasui N, Suzuki A, Nishimura H, Suzuki K, Abe T. Long-term follow-up study of unruptured intracranial aneurysms. Neurosurgery 1997;40:1155-9.\u003c/li\u003e\n\u003cli\u003eBrown RD Jr, Huston J, Hornung R, et al. Screening for brain aneurysm in the Familial Intracranial Aneurysm study: frequency and predictors of lesion detection. J Neurosurg.2008;108(6):1132-1138.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"subarachnoid hemorrhage, intracranial aneurysm, internal carotid artery occlusion, blood flow, risk factors","lastPublishedDoi":"10.21203/rs.3.rs-4793934/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4793934/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground and Purpose\u003c/h2\u003e \u003cp\u003eIntracranial aneurysms combined with spontaneous internal carotid artery occlusion (ICAO) are a rare and serious vascular disorder. Currently, there is only limited information available on the clinical characteristics of these patients and the risk factors for aneurysm rupture. Our objective is to describe the clinical features of these patients and predict the risk factors for the rupture of unruptured intracranial aneurysms (UIAs) combined with ICAO.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eWe retrospectively analyzed cases of intracranial aneurysms with concurrent spontaneous ICAO from the Chinese Multicenter Aneurysm Database(CMAD). We collected population demographic characteristics and clinical data using a standardized case questionnaire from CMAD. Binary logistic regression analysis was used to identify risk factors for rupture of UIA associated with combined ICAO.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eWe identified 93 patients with intracranial aneurysms combined with ICAO, including 38 females and 55 males, with an average age of 60.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.5years (ranging from 32 to 79 years old). Among those with ICAO, 52 had ruptured intracranial aneurysms (RIAs) and 41 had UIAs. Specifically, there were 81 cases of unilateral ICAO, with 16 aneurysms located on the same side as the ICAO, 22 in the midline, and 43 on the opposite side of the ICAO; 12 cases were bilateral ICAO. Binary logistic regression analysis indicated that risk factors associated with the rupture of UIAs with ICAO included bilateral internal carotid artery occlusion and aneurysms in the posterior circulation. Furthermore, multivariate analysis showed that posterior circulation aneurysms are an independent risk factor for the rupture of UIAs with ICAO.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eWe have described and analyzed the clinical characteristics and risk factors influencing the rupture of intracranial aneurysms in patients with ICAO. The study found that the location of the aneurysm is an important risk factor for the rupture of UIAs combined with ICAO.\u003c/p\u003e","manuscriptTitle":"Intracranial Aneurysm Location: Key Factor in Ruptures with Internal Carotid Artery Occlusion","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-21 12:18:04","doi":"10.21203/rs.3.rs-4793934/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-05T08:05:57+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-31T12:50:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-03-26T23:11:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"111914610304898041426062869887997515477","date":"2025-03-18T06:14:05+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"257500165710614898762214820385392845366","date":"2025-03-18T00:40:20+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-09-02T12:10:44+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-07-25T22:32:17+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-07-25T08:20:38+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-07-25T08:20:32+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Neurology","date":"2024-07-24T09:03:21+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-neurology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"nurl","sideBox":"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/nurl","title":"BMC Neurology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"011404cb-77d0-4986-93bd-509bb1b048a0","owner":[],"postedDate":"August 21st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-08-18T16:05:23+00:00","versionOfRecord":{"articleIdentity":"rs-4793934","link":"https://doi.org/10.1186/s12883-025-04362-7","journal":{"identity":"bmc-neurology","isVorOnly":false,"title":"BMC Neurology"},"publishedOn":"2025-08-13 15:57:41","publishedOnDateReadable":"August 13th, 2025"},"versionCreatedAt":"2024-08-21 12:18:04","video":"","vorDoi":"10.1186/s12883-025-04362-7","vorDoiUrl":"https://doi.org/10.1186/s12883-025-04362-7","workflowStages":[]},"version":"v1","identity":"rs-4793934","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4793934","identity":"rs-4793934","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}