Aneurysms in High-Altitude Populations: Epidemiology, Management, and Rupture Risk

Aneurysms in High-Altitude Populations: Epidemiology, Management, and Rupture Risk | 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 Aneurysms in High-Altitude Populations: Epidemiology, Management, and Rupture Risk Chi Lin, Jianbo Zhang, Xiaolong Zhao, Xitao Zong, Yanxiang Tong, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9608513/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background This study aimed to explore the epidemiology, treatment approaches, and rupture risk factors of high-altitude IAs. Methods Patients in the UIAs and RIAs groups were analyzed retrospectively. Statistical analysis of aneurysm incidence, location, and size was conducted between the two groups. Logistic regression and ROC curve analyses were then used to identify the AR (height/neck width ratio) and assess NUAD (Non‑compliant use of antihypertensive drugs) and AIMF (Aneurysms with irregular morphological features) as risk factors for IAs rupture. Finally, the patient's discharge Glasgow Outcome Scale (GOS) score was calculated to evaluate the rate of good outcomes. Results The incidence of ICA (36.10%) in the UIAs group was significantly greater than the incidence of ICA (22.84%) in the RIAs group. The incidence of ACA (17.56%) in the UIAs group was significantly lower than the incidence of ACA (28.41%) in the RIAs group. The occurrence of medium-sized aneurysms in the ACA (4.33%) and MCA (12.99%) in the UIAs group was significantly lower than that in the RIAs group (14.41%) and MCA group (20.95%). The GOS was significantly higher in the UIAs group than in the RIAs group. Regression data showed AR, NUAD and AIMF prediction was valid respectively. Conclusions The incidence of ACA rupture was greater in patients with ruptured aneurysms, and the risk of rupture of medium and small aneurysms was lower in the UIAs group. AR served as a critical predictor of rupture in IAs at distinct anatomical sites. Additional factors contributing to IAs rupture included NUAD and AIMF. Intracranial aneurysms Epidemiological features High altitude Aneurysm rupture Risk Figures Figure 1 Figure 2 Figure 3 Introduction An aneurysm refers to a cystic protrusion above the intracranial artery wall. The wall of the protrusion is very thin and easily ruptures and bleeds[1]. The main reasons for the formation of an aneurysm are as follows. First, hypertension can develop. Long-term hypertension causes hardening and hyalinoid changes in the intracranial arterial blood tube wall, which increases the brittleness of the blood vessel. In the case of increased blood flow, cystic protrusions in the blood vessel wall will form aneurysms[2]. Second, genetic factors cause the loss of elastic fibers in the intracranial artery wall, which can cause weakness of the blood vessel wall and easily lead to hemangioma[3]. Third, viral infection, which can also lead to arteritis, can cause damage to the wall of the artery, and then, cystic protrusions can form aneurysms[4]. Fourth, craniocerebral trauma or damage to blood vessel walls caused by iatrogenic factors can result in the occurrence of aneurysms[5]. The main symptom of aneurysms is subarachnoid hemorrhage (SAH). It is also the main cause of disability in up to 40% of affected people and places a large burden on the country, society and families[6]. High altitude refers to the area above 1500 m[7]. There are more patients with high blood pressure in high altitudes than in low altitudes[8], and the risk of aneurysm formation is greater in high altitudes than in low altitudes. The incidence of arterial aneurysms is high in high altitudes, and it may also be related to slow recovery after cerebrovascular injury injury in hypoxic environments[9]. It is also possible that it is the dietary habits of the population. In high-altitude areas with high altitude and oxygen deficiency, people like to eat high sodium and high-fat foods. Studies have reported the incidence of aneurysms in low altitudes. There are more epidemiological characteristics and risk factors for aneurysm rupture in low-altitude areas[10], but there are no reports on the risk factors for aneurysm rupture in high-altitude areas. In this retrospective study, the epidemiological characteristics and rupture risk factors for aneurysms were summarized, which is helpful for planning, screening and prevention strategies and predicting the prognosis of individual patients in high altitudes. Patients and Methods Patient selection This was a retrospective analysis of imaging data from patients with altitudes above 1500 m in the Neurosurgery Department of Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state) from 01/01/2015 to 30/09/2023. Patients were diagnosed with intracranial aneurysms (IAs) through digital subtraction angiography (DSA) (Canon INFX-9000C, Japan), computed tomography angiography (CTA) (Canon 320 Rows CT Aquilion One, Japan), or magnetic resonance angiography (MRA) (3.0T magnetic resonance imaging, GE Discovery MR750W, USA) examinations. The inclusion criteria were as follows: ruptured intracranial aneurysm (RIAs) group (Figure 1) and Hunt–Hess score ranging from "1" to "5" based on the patient's condition[11]. In the Unruptured intracranial aneurysms (UIAs) group (Figure 1), the Hut–Hess score was 0. Exclusion criteria is provided (Figure 1). This retrospective study was approved by the Medical Ethics Committee of Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state) ((2024) YDNLSN0.97). The collected data included sex, age, ethnicity, comorbid underlying disease, ratio of aneurysm height to neck width (AR), aneurysm size, Intracranial Aneurysm Morphology, Non‑compliant use of antihypertensive drugs (NUAD), blood glucose, admission Hunt–Hess score, and Glasgow Outcome Scale (GOS) score at discharge. The treatment methods were determined based on the patient's physical condition, imaging data, and choice of the patient and their family and were divided into interventional treatment and surgical clipping. Timely follow-up of head CT, CTA or MRA was conducted after surgery. The locations of the aneurysms included the anterior cerebral artery (ACA), internal carotid artery (ICA), middle cerebral artery (MCA) and posterior circulation (PCA), which indicated that the ACA included the anterior communication and pericallum; the ICA included the ocular segment, posterior communication, bifurcation, and anterior choroidal artery; the MCA included the proximal, bifurcation, and distal segments; and the PCA included the basal bifurcation, basal trunk, superior cerebellum, anterior inferior cerebellum, posterior inferior cerebellum, vertebral artery, and posterior cerebral artery. In the UIAs group, the AR of the multiple aneurysms were averaged, whereas in the RIAs group, the AR of the responsible aneurysms were determined if bleeding was responsible, and if the AR of the responsible aneurysms were not determined, the AR of the multiple aneurysms were averaged. Multiple aneurysms were counted by location. If multiple aneurysms occurred at the same location, 1 was counted. The size of multiple aneurysms was calculated according to the actual number of aneurysms. Treatment method selection The choice between interventional treatment and surgical clipping treatment was mainly based on imaging data to maximize patient benefits. In addition, if both treatment methods were acceptable, the results tended to be based on the opinions of the patients and their families. Concept of detection indicators The maximum diameter of the aneurysm was divided into small (<5 mm), medium (5 mm ≤ diameter<15 mm), large (15 mm ≤ diameter<25 mm), and giant (diameter ≥ 25 mm)[12, 13]. AR was defined as the ratio of aneurysm height to aneurysm neck width, where aneurysm height is defined as the vertical distance from the aneurysm neck plane to the farthest point of the aneurysm[14]. Blood blister-like aneurysm (BBA) has diagnostic criteria based on independent diagnosis by experienced neurosurgeons and radiologists[15]. Aneurysms with irregular morphological features (AIMF): Based on their morphological appearance, intracranial aneurysms were categorized into two subtypes: irregular (characterized by the presence of lobulation, blebs, or wall protrusions) and regular (devoid of these irregular morphological characteristics) Outcomes At discharge, patients were scored using the Glasgow Outcome Scale (GOS). The scoring criteria were as follows: good recovery (5), moderate disability (4), severe disability (3), vegetative state (2), and death (1). The patients were divided into 2 outcome groups: a good outcome group, which was defined as independent (GOS scores, 4-5), and a poor outcome group, which was defined as dependent (GOS scores, 3-1)[16, 17] . Statistical methods Continuous variables that followed a normal distribution are represented by x̄ ± s , and independent sample t tests were used for comparisons between two groups. If the data did not follow a normal distribution, they were represented by M (median) (Q1, Q3), and comparisons between the two groups were conducted using the Mann‒Whitney U test. Categorical variables are expressed as frequencies and percentages, and comparisons of rates between two groups were performed using χ2 tests. The AR, NUAD and AIMF data were subjected to logistic regression analysis to predict aneurysm rupture. An ROC curve model was used to evaluate the effectiveness of the AR in predicting IAs rupture. Differences were considered statistically significant at P <0.05. Statistical analysis was performed via SPSS Statistics (version 23, IBM, USA). Images were generated via GraphPad Prism (version 8, GraphPad Software, USA). A two-sided p value < 0.05 was considered to indicate statistical significance. Results Participant characteristics Among the 628 patients with IAs, only 532 met the inclusion criteria (Figure 1). The study patients with IAs consisted of 262 (49.25%) males and 270 (50.75%) females. The UIAs group included 93 (49.73%) males and 94 (50.27%) females (Table 1). The RIAs group included 169 (48.99%) males and 176 (51.01%) females (Table 1). In particular, the percentage of patients with hypertension and heart disease in the UIAs group was significantly greater than that in the RIAs group, and there was no significant difference in the percentage of patients with diabetes (Table 1). Fifty-one patients (27.27%) in the UIAs group were treated, including 44 patients (23.52%) who received intervention, 7 patients (3.74%) who received surgical clipping (Table 1), and 136 patients (72.73%) who were not treated at the Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state) or who were abandoned by patients or their families. Two hundred and forty-three patients (70.43%) in the RIAs group were treated, including 155 patients (44.93%) of interventional treatment, 88 patients (25.51%) of surgical clipping and 101 patients (29.28%) who did not receive treatment at the same hospital or were abandoned by patients or their families (Table 1). The age group with the highest incidence of aneurysms was between 51 and 60 years (Figure 2A and B). Outcome Analysis The GOS of the UIAs group was significantly greater than that of the RIAs group (Table 1). The rate of good outcomes in the UIAs group was significantly greater than that in the RIAs group (Figure 2C). Characteristics of IAs A total of 564 IAs (including 1 patient with multiple IAs) were found based on location, including 205 (36.35%) in the UIAs group and 359 (63.65%) in the RIAs group. The incidence of the ICA (74, 36.10%) in the UIAs group was significantly greater than the incidence of the ICA (82, 22.84%) in the RIAs group. In contrast, the incidence rate of the ACA (36, 17.56%) in the UIAs group was significantly lower than the incidence rate of the ACA (102, 28.41%) in the RIAs group (Table 2). There was no significant difference in the incidence rates of the MCA 69 (33.66%) and PCA 26 (12.68%) in the UIAs group compared with the incidence rates of the MCA 141 (39.28%) and PCA 34 (9.47%) in the RIAs group (Table 2). The UIAs group had 231 aneurysms, whereas the RIAs group had 444 aneurysms (multiple aneurysms, each assessed by standard size). Only the RIAs group had one case of giant aneurysm, whereas the UIAs group did not. There was no significant difference in the incidence of the ICA 3 (1.3%), ACA 1 (0.43%), MCA 5 (2.16%), or PCA 3 (1.3%) between the UIAs group and the RIAs group in terms of the ICA 4 (0.9%), ACA 2 (0.45%), MCA 4 (0.9%), and PCA 1 (0.23%) for the occurrence of large aneurysms. The occurrence of middle -sized aneurysms in the ACA (10, 4.33%) and MCA (30, 12.99%) in the UIAs group was significantly lower than that in the RIAs group (64, 14.41%) and MCA (93, 20.95%) in the ACA group (Table 2). However, the incidence of the ICA23 (9.96%) and PCA11 (4.76%) in the UIAs group was not significantly different from that in the RIAs group (ICA55 (12.39%) and PCA15 (3.38%)) (Table 2). The incidence of small aneurysms of the ICA in the two groups was significantly greater in the UIAs group (60, 25.97%) than in the RIAs group (40, 9.01%), while the incidence of the ACA in the UIAs group (26, 11.26%) was significantly lower than that in the RIAs group (80, 18.02%) (Table 2). The incidence rates of the MCA 44 (19.05%) and PCA 15 (6.49%) in the UIAs group were not significantly different from those in the RIAs group (MCA 66 (14.86%) and PCA 19 (4.28%)). The incidence of multiple aneurysms in the UIAs group (32 [17.11%]) was not significantly different from that in the RIAs group (61 [17.68%]) (Table 2). The incidence of BBA in UIAs Group 7 (3.74%) was significantly lower than that in RIAs Group 31 (8.99%) (Table 2). The ability of the AR to predict aneurysm rupture AR analysis revealed that the risk of aneurysm rupture in different locations was significantly lower in the UIAs group than in the RIAs group. Logistic regression curves and ROC curves were used for the analysis of the two groups of ACA, ICA, MCA and PCA aneurysms. Logistic regression and ROC curve analysis of the AR data were conducted. Compared with that of the RIAs group, the AR of the UIAs group was significantly lower than that of the RIAs group (Table 2). The regression data showed β 0, β 1 and OR (Figure 2D and Figure 3A, C, E, G), and ROC curve analysis revealed that the area under the curve (AUC) was significant difference (Figure 3B, D, F, H). Predictive value of other factors for aneurysm rupture Analysis of additional risk factors for IAs rupture indicated that NUAD and AIMF were risk factors for such events in the high-altitude setting (Table 3). Discussion The characteristics of aneurysms in high altitudes are similar to those in lower altitudes, and the age characteristics are also consistent with those in the lower altitudes. The proportion of patients with hypertension and heart disease had a higher probability of going to the hospital for examination, so these patients had a higher detection rate of aneurysms in the UIAs group. The main reason was that patients with hypertension and heart disease often visit the hospital for examination, and the rate of cerebrovascular examination was greater than that in the RIAs group. The UIAs group had a high rate of hypertension and heart disease, and the location and size of the aneurysms were significantly different between the UIAs group and the RIAs group. AR serves as a critical predictor of rupture in intracranial aneurysms at distinct anatomical sites. Additional factors contributing to IAs rupture include NUAD and AIMF. The peak age of aneurysm onset in high altitude was similar to that reported at normal times, mainly in the 51–60 years age group[ 18 ]. In this age group, it was important to check the brain blood and brain regularly. In the epidemic population, the incidence of aneurysms was slightly greater in women than in men, similar to that reported in Plains[ 19 ]. According to the analysis of the current status of high-altitude aneurysm treatment, interventional surgery is relatively popular in high altitudes, and relatively few patients choose clipping surgery, which is in line with the current treatment methods. In addition, the proportion of UIAs patients who chose to stop treatment was relatively high. The main reason was that some patients and their families were asymptomatic at present or were afraid of surgical risks, so they chose to observe and follow up and then start treatment when they were at risk of rupture. A small number of patients and their families chose other hospitals for treatment. In the RIAs group, due to aneurysm rupture accompanied by SAH, most of the patients were in a dangerous condition when they came to the hospital, and more patients and their families chose hospitalization, while some patients and their families also chose to give up treatment. Patients who chose other hospital treatments or whose families considered serious illness were excluded from treatment. From the perspective of the arterial origin and aneurysm location, the ICA had a greater rate of aneurysm occurrence in the UIAs group, whereas the ACA had a greater rate of aneurysm occurrence in the RIAs group. According to this ratio, if a patient's unruptured aneurysm was located in the ICA, the patient should be prepared for treatment in advance because the aneurysm might rupture at any time. However, in terms of the size of the aneurysms themselves, there was no significant difference in the incidence of large aneurysm rupture between the two groups, whereas there were significant differences in the incidence of ruptured bleeding in different parts of the medium and small aneurysms between the two groups. There were differences in the ACA and MCA between medium-sized aneurysms and between the ICA and ACA between small-sized aneurysms. If patients with aneurysms of different sizes and different locations are at risk of rupture, further treatment can be administered early. Among patients with ruptured aneurysms in high-altitude areas, the incidence of BBAs (8.99%) was greater than that in low-altitude areas (0.3%-6.6%)[ 20 , 21 ], which might be related to the special hypoxic environment at high altitudes. AR has a good ability to predict aneurysm rupture in high altitudes, and many studies in plain areas have shown that AR could play a role in determining whether AR is a risk factor for aneurysm rupture. According to our logistic regression analysis, the ACA, ICA, MCA and PCA all had obvious predictive effects. AR has good ability to predict aneurysm rupture in high altitudes, and many studies in plain areas have shown that AR can play a role in determining whether AR is a risk factor for aneurysm rupture[ 22 , 23 ]. According to our logistic regression analysis, the ACA, ICA, MCA and PCA all had obvious predictive effects. Moreover, a ROC curve was used to determine the sensitivity and specificity of the AR in different aneurysm locations, and the analysis revealed that the AR had an obvious predictive effect. Additional risk factors for predicting in IAs rupture included NUAD and AIMF. Specifically, NUAD defined as irregular intake of antihypertensive drugs induced blood pressure fluctuations, which elevated the risk of IAs rupture, consistent with findings from relevant studies[ 24 ]. Similarly, AIMF was another risk factor for IAs rupture, which was also in line with the results of previous research[ 24 ]. An analysis of the patients’ GOS, revealed that the UIAs group had a significantly better prognosis than did the RIAs group, and the Hunt–Hess score at admission was also crucial. Given tha the admission Hunt–Hess score of the UIAs group was "0", an effective GOS correlation could not be established. However, the Hunt–Hess score at admission in the RIAs group was negatively correlated with the GOS score[ 25 ]. The lower the Hunt–Hess score is, the greater the GOS score at discharge and, the better the prognosis, and the more severe the neurological damage upon admission is, the greater the Hunt–Hess score, and the worse the discharge prognosis. By analyzing the epidemic characteristics and treatment status of high-altitude aneurysms, as well as assessing the risk of rupture by AR, we can effectively grasp the development pattern and treatment of high-altitude aneurysms, providing assistance for the future understanding of high-altitude aneurysms. Conclusions We summarized the common locations and rupture-prone sites of IAs in high-altitude populations, as well as the risk factors contributing to IAs rupture. In patients with ruptured aneurysms, the incidence of ICA rupture was greater in patients with unruptured aneurysms, whereas the incidence of ACA rupture was greater in patients with ruptured aneurysms, and the risk of rupture of medium and small aneurysms was lower in the unruptured group. AR serves as a critical predictor of rupture in intracranial aneurysms at distinct anatomical sites. Additional factors contributing to IAS rupture include NUAD and AIMF. Abbreviations UIAs: Unruptured intracranial aneurysms, RIAs: Ruptured intracranial aneurysms, SAH: Subarachnoid hemorrhage, IAs: Intracranial aneurysms, DSA: Digital subtraction angiography, CTA: Computed tomography angiography, MRA: Magnetic resonance angiography, GOS: Glasgow Outcome Scale, AR: Ratio of aneurysm height to neck width, BBA: Blood blister-like aneurysm, ACA: Anterior cerebral artery, ICA: Internal carotid artery, MCA: Middle cerebral artery, PCA: Posterior circulation. NUAD: Non‑compliant use of antihypertensive drugs, AIMF: Aneurysms with irregular morphological features. Declarations Disclosure statement No potential conflict of interest was reported by the author(s). Funding This work was supported by Grant No. XZ202201YD0028C from Central government funds for guiding local scientific and technological development. Availability of Data and Materials All data generated or analyzed during this study are included in this published article. Ethics approval and Consent to Participate The study was conducted in accordance with the Declaration of Helsinki.The Medical Ethics Committee of the First People's Hospital of Honghe State (Southern central hospital of yunnan province). All of the participants provided signed informed consent. Author contributions L.W., C.L., and J. Z.conceptualized and designed the study. T.Z., Y.T., F.W., J.W., and L.W. were responsible for material preparation and data analysis.X.Z.; L.W. and J.W. drafted the original manuscript. All authors have read and approved the final manuscript for publication. Acknowledgements We extend our deepest gratitude to all patients and their caregivers who participated in this study for their valuable contributions and patience. At the same time, we also appreciate the efforts of the participating doctors and other relevant personnel. References Pavlos T, Ahmad S, Nikolaos M, Eric C P, Chrissa S, Leonardo R-C, et al. Aneurysm Formation, Growth, and Rupture: The Biology and Physics of Cerebral Aneurysms. World Neurosurg. 2019; 130. https://doi.org/10.1016/j.wneu.2019.07.093 Karhunen V, Bakker MK, Ruigrok YM, Gill D, Larsson SC. Modifiable Risk Factors for Intracranial Aneurysm and Aneurysmal Subarachnoid Hemorrhage: A Mendelian Randomization Study. J Am Heart Assoc. 2021; 10: e022277. https://doi.org/10.1161/jaha.121.022277 Bakker MK, van der Spek RAA, van Rheenen W, Morel S, Bourcier R, Hostettler IC, et al. Genome-wide association study of intracranial aneurysms identifies 17 risk loci and genetic overlap with clinical risk factors. Nat Genet. 2020; 52: 1303-1313. https://doi.org/10.1038/s41588-020-00725-7 Rabelo NN, Samaia da Silva Coelho AC, Telles JPM, Coelho G, de Souza CS, Tozetto-Mendoza TR, et al. Human herpesvirus DNA occurrence in intracranial aneurysmal wall: illustrative case. J Neurosurg Case Lessons. 2021; 2: Case21301. https://doi.org/10.3171/case21301 Griswold D, Fernandez L, Rubiano A. Traumatic Subarachnoid Hemorrhage: A Scoping Review. J Neurotrauma. 2022; 39: 35-48. https://doi.org/10.1089/neu.2021.0007 Macdonald R, Jaja B, Cusimano M, Etminan N, Hanggi D, Hasan D, et al. SAHIT Investigators--on the outcome of some subarachnoid hemorrhage clinical trials. Translational stroke research. 2013; 4: 286-296. https://doi.org/10.1007/s12975-012-0242-1 Mallet RT, Burtscher J, Richalet JP, Millet GP, Burtscher M. Impact of High Altitude on Cardiovascular Health: Current Perspectives. Vasc Health Risk Manag. 2021; 17: 317-335. https://doi.org/10.2147/vhrm.s294121 Bilo G, Caravita S, Torlasco C, Parati G. Blood pressure at high altitude: physiology and clinical implications. Kardiologia polska. 2019; 77: 596-603. https://doi.org/10.33963/kp.14832 Silpanisong J, Pearce WJ. Vasotrophic regulation of age-dependent hypoxic cerebrovascular remodeling. Curr Vasc Pharmacol. 2013; 11: 544-563. https://doi.org/10.2174/1570161111311050002 Kaminogo M, Yonekura M, Shibata S. Incidence and outcome of multiple intracranial aneurysms in a defined population. Stroke. 2003; 34: 16-21. https://doi.org/10.1161/01.str.0000046763.48330.ad Yifan Y, Seidu A R, Zhigang L. The impact of residual hematoma after evacuation on the outcomes of patients with ruptured intracranial aneurysms with intracerebral hematoma: A longitudinal single-center observational study. Medicine (Baltimore). 2022; 101. https://doi.org/10.1097/md.0000000000030129 Wei Z, Peixi L, Yanlong T, Yuxiang G, Bin X, Liang C, et al. Complex middle cerebral artery aneurysms: a new classification based on the angioarchitecture and surgical strategies. Acta Neurochir (Wien). 2013; 155. https://doi.org/10.1007/s00701-013-1751-8 Wang L, He W, Zhang H, Wang S, Zhao Y, Tian F, et al. Comparison of transcranial color Doppler sonography without and with contrast enhancement for detection and characterization of intracranial aneurysms. Journal of clinical ultrasound : JCU. 2012; 40: 535-539. https://doi.org/10.1002/jcu.21911 Yin JH, Su SX, Zhang X, Bi YM, Duan CZ, Huang WM, et al. U-Shaped Association of Aspect Ratio and Single Intracranial Aneurysm Rupture in Chinese Patients: A Cross-Sectional Study. Front Neurol. 2021; 12: 731129. https://doi.org/10.3389/fneur.2021.731129 Xiao-Dong Z, Peng H, Chuan H, Yue-Shan F, Gui-Lin L, Hong-Qi Z. Current Knowledge of and Perspectives about the Pathogenesis of Blood Blister-like Aneurysms of the Internal Carotid Artery: A Review of the Literature. Int J Med Sci. 2021; 18. https://doi.org/10.7150/ijms.53154 Chen DY, Wu PF, Zhu XY, Zhao WB, Shao SF, Xie JR, et al. Risk factors and predictive model of cerebral edema after road traffic accidents-related traumatic brain injury. Chin J Traumatol. 2024. https://doi.org/10.1016/j.cjtee.2024.02.001 Linjie W, Chi L, Xingsen X, Shiju J, Yalan D, Li P, et al. The Effect of Hemoglobin Concentration on Hyperbaric Oxygen and Non-hyperbaric Oxygen in the Treatment of Hypertensive Intracerebral Hemorrhage After Operation at the High Altitude. Front Hum Neurosci. 2022; 16. https://doi.org/10.3389/fnhum.2022.834427 Claassen J, Park S. Spontaneous subarachnoid haemorrhage. Lancet. 2022; 400: 846-862. https://doi.org/10.1016/s0140-6736(22)00938-2 Krzyżewski RM, Kliś KM, Kucala R, Polak J, Kwinta BM, Starowicz-Filip A, et al. Intracranial aneurysm distribution and characteristics according to gender. Br J Neurosurg. 2018; 32: 541-543. https://doi.org/10.1080/02688697.2018.1518514 Sook Young S, Yong Sam S, Kyung Gi C, Sun Yong K, Se Hyuk K, Young Hwan A, et al. Blood blister-like aneurysms at nonbranching sites of the internal carotid artery. J Neurosurg. 2006; 105. https://doi.org/10.3171/jns.2006.105.3.400 Geoffrey W P, Christopher A S, Ramesh G. Endovascular treatment of blister aneurysms. Neurosurg Focus. 2017; 42. https://doi.org/10.3171/2017.3.focus1751 Lombarski L, Kunert P, Tarka S, Piechna A, Kujawski S, Marchel A. Unruptured intracranial aneurysms: relation between morphology and wall strength. Neurologia i neurochirurgia polska. 2022; 56: 410-416. https://doi.org/10.5603/PJNNS.a2022.0053 Ma P, Li Y, Feng Y, Wu G, Li B, Wu H. The Application of Multiple Magnetic Resonance Scanning Techniques in Evaluating the Stability of Intracranial Aneurysms. International journal of general medicine. 2023; 16: 2003-2011. https://doi.org/10.2147/ijgm.s402255 Zhong P, Lu Z, Li Z, Li T, Lan Q, Liu J, et al. Impact of premorbid hypertension and renin-angiotensin-aldosterone system inhibitors on the severity of aneurysmal subarachnoid haemorrhage: a multicentre study. Stroke Vasc Neurol. 2025; 10. https://doi.org/10.1136/svn-2023-003052 C C, A R. Neurological and psychosocial outcome after subarachnoid haemorrhage, and the hunt and hess scale as a predictor of clinical outcome. Zentralbl Neurochir. 2005; 66. https://doi.org/10.1055/s-2005-836477 Tables Tables 1 to 3 are available in the supplementary files section Additional Declarations No competing interests reported. Supplementary Files Table1.docx Table2.docx Table3.docx Cite Share Download PDF Status: Posted Version 1 posted 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. We do this by developing innovative software and high quality services for the global research community. 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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-9608513","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":636770084,"identity":"4c2a17b3-5302-41ea-861d-379d7c34eaf2","order_by":0,"name":"Chi Lin","email":"","orcid":"","institution":"Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state)","correspondingAuthor":false,"prefix":"","firstName":"Chi","middleName":"","lastName":"Lin","suffix":""},{"id":636770085,"identity":"af1f9e30-c794-4c24-a852-c6569fe6bb15","order_by":1,"name":"Jianbo Zhang","email":"","orcid":"","institution":"The 925th Hospital of PLA, Guiyang, People’s Republic of China","correspondingAuthor":false,"prefix":"","firstName":"Jianbo","middleName":"","lastName":"Zhang","suffix":""},{"id":636770086,"identity":"8e7cccf8-f361-4893-b8d5-ab6365d12e23","order_by":2,"name":"Xiaolong Zhao","email":"","orcid":"","institution":"PLA 956th Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xiaolong","middleName":"","lastName":"Zhao","suffix":""},{"id":636770087,"identity":"3018e6ed-85da-4450-a205-fdbe77d42e49","order_by":3,"name":"Xitao Zong","email":"","orcid":"","institution":"Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state)","correspondingAuthor":false,"prefix":"","firstName":"Xitao","middleName":"","lastName":"Zong","suffix":""},{"id":636770088,"identity":"8a6d2a6a-1b36-4e20-8566-c908f9e1f873","order_by":4,"name":"Yanxiang Tong","email":"","orcid":"","institution":"Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state)","correspondingAuthor":false,"prefix":"","firstName":"Yanxiang","middleName":"","lastName":"Tong","suffix":""},{"id":636770090,"identity":"3a66121b-8d77-481e-be18-01ff03ce0eb9","order_by":5,"name":"Fei Wang","email":"","orcid":"","institution":"PLA 956th Hospital","correspondingAuthor":false,"prefix":"","firstName":"Fei","middleName":"","lastName":"Wang","suffix":""},{"id":636770092,"identity":"53ada63f-615c-45ff-b547-6e91db2ec03d","order_by":6,"name":"Jun Wang","email":"","orcid":"","institution":"PLA 956th Hospital","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Wang","suffix":""},{"id":636770094,"identity":"908c94eb-49df-4ce5-b624-cb5638b7078a","order_by":7,"name":"Lixia Wu","email":"","orcid":"","institution":"Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state)","correspondingAuthor":false,"prefix":"","firstName":"Lixia","middleName":"","lastName":"Wu","suffix":""},{"id":636770096,"identity":"4ed038a6-dc20-4f24-b9c0-97cdb2d3edba","order_by":8,"name":"JiaXiong Wang","email":"","orcid":"","institution":"PLA 956th Hospital","correspondingAuthor":false,"prefix":"","firstName":"JiaXiong","middleName":"","lastName":"Wang","suffix":""},{"id":636770097,"identity":"1638cb8e-070c-4dc2-89a9-fc8f63667b1f","order_by":9,"name":"Linjie Wei","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4klEQVRIiWNgGAWjYFACxsYDCQxsPAzszQcffKiQkJMnQksDRAvPsWTDGWcsjA0biLDnAJiUyDGT5m2rSIRycQOD480NBx7u4JPhB9kyc55EAmMD88NHN/BpOXOw4UDiGTYeyXagXz5uk8hjZ2AzNs7Bo8XsRiJQSxsbj8EZkC3bJIoZG3jYpPFquf8QosX+BsgvcySAJhDScoMRagvY+w1EaLE/A3WYBMhhM45JGBs2E/CLZPvxhw9/th2z5wd5/0NNnZw8e/PDx/i0QMExJDYzYeUgUEOcslEwCkbBKBiZAABSwlSEogC6bAAAAABJRU5ErkJggg==","orcid":"","institution":"PLA 956th Hospital","correspondingAuthor":true,"prefix":"","firstName":"Linjie","middleName":"","lastName":"Wei","suffix":""}],"badges":[],"createdAt":"2026-05-04 12:40:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9608513/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9608513/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109405911,"identity":"8e3bd548-b675-41b4-9414-4bccb7871a2f","added_by":"auto","created_at":"2026-05-17 13:22:16","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":973167,"visible":true,"origin":"","legend":"\u003cp\u003eA flowchart of the identification and grouping process for eligible patients.\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/8f635645898e17a24af91a50.png"},{"id":109405898,"identity":"70727e66-183a-4f80-bf07-f8985881ef06","added_by":"auto","created_at":"2026-05-17 13:22:05","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2800763,"visible":true,"origin":"","legend":"\u003cp\u003eA: The age distribution map of UIAs group aneurysms showed that the peak age range for discovery was between 51 and 60 years. B: The age distribution map for the discovery of aneurysms in the RIAs group showed that the peak age range for discovery was between 51 and 60 years. C: There was a significant difference in the percentage of patients with good outcomes between the groups. D: The odds ratios and 95% CI for different locations of the ACA, ICA, MCA and PCA. ***P \u0026lt; 0.001 was determined by the chi-square test.\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/e212729554fb61b21f335a8c.png"},{"id":109406625,"identity":"82fd19a0-44cf-4d60-8c99-a29bc11769cc","added_by":"auto","created_at":"2026-05-17 13:29:08","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":6883390,"visible":true,"origin":"","legend":"\u003cp\u003eLogistic regression analysis of the AR for predicting the risk of aneurysm rupture at different locations and the ROC curve were used to measure the AR for aneurysm rupture at different locations. A-B, C-D, E-F and G-H represent the AR logistic regression analysis and ROC curves of the ACA, ICA, MCA and PCA groups, respectively.\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/93c0268dfd328c7c2cf1fdcf.png"},{"id":109535265,"identity":"dfbc9b3b-2c90-4ec4-9073-503e408ef9fa","added_by":"auto","created_at":"2026-05-19 08:56:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":12158153,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/3b93b854-3b62-4934-976b-12ff475c1e9e.pdf"},{"id":109405910,"identity":"ec26aa52-d8a1-4db1-96c4-d2f9f2f83704","added_by":"auto","created_at":"2026-05-17 13:22:16","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":19461,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/09f306d1cb251ce641859161.docx"},{"id":109405897,"identity":"cdfad917-7d30-48b7-b8ce-b3cc20b636c2","added_by":"auto","created_at":"2026-05-17 13:22:05","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":23765,"visible":true,"origin":"","legend":"","description":"","filename":"Table2.docx","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/890e6a271411e832174a4578.docx"},{"id":109406327,"identity":"80efd854-a04c-41f5-a629-5f9cacdfc767","added_by":"auto","created_at":"2026-05-17 13:27:45","extension":"docx","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":15177,"visible":true,"origin":"","legend":"","description":"","filename":"Table3.docx","url":"https://assets-eu.researchsquare.com/files/rs-9608513/v1/fab234ce65438f7ee84ae9f5.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Aneurysms in High-Altitude Populations: Epidemiology, Management, and Rupture Risk","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAn aneurysm refers to a cystic protrusion above the intracranial artery wall. The wall of the protrusion is very thin and easily ruptures and bleeds[1]. The main reasons for the formation of an aneurysm are as follows. First, hypertension can develop. Long-term hypertension causes hardening and hyalinoid changes in the intracranial arterial blood tube wall, which increases the brittleness of the blood vessel. In the case of increased blood flow, cystic protrusions in the blood vessel wall will form aneurysms[2]. Second, genetic factors cause the loss of elastic fibers in the intracranial artery wall, which can cause weakness of the blood vessel wall and easily lead to hemangioma[3]. Third, viral infection, which can also lead to arteritis, can cause damage to the wall of the artery, and then, cystic protrusions can form aneurysms[4]. Fourth, craniocerebral trauma or damage to blood vessel walls caused by iatrogenic factors can result in the occurrence of aneurysms[5]. The main symptom of aneurysms is subarachnoid hemorrhage (SAH). It is also the main cause of disability in up to 40% of affected people and places a large burden on the country, society and families[6]. High altitude refers to the area above 1500 m[7]. There are more patients with high blood pressure in high altitudes than in low altitudes[8], and the risk of aneurysm formation is greater in high altitudes than in low altitudes. The incidence of arterial aneurysms is high in high altitudes, and it may also be related to slow recovery after cerebrovascular injury injury in hypoxic environments[9]. It is also possible that it is the dietary habits of the population. In high-altitude areas with high altitude and oxygen deficiency, people like to eat high sodium and high-fat foods. Studies have reported the incidence of aneurysms in low altitudes. There are more epidemiological characteristics and risk factors for aneurysm rupture in low-altitude areas[10], but there are no reports on the risk factors for aneurysm rupture in high-altitude areas. In this retrospective study, the epidemiological characteristics and rupture risk factors for aneurysms were summarized, which is helpful for planning, screening and prevention strategies and predicting the prognosis of individual patients in high altitudes.\u003c/p\u003e"},{"header":"Patients and Methods","content":"\u003cp\u003e\u003cem\u003ePatient selection\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThis was a retrospective analysis of imaging data from patients with altitudes above 1500 m in the Neurosurgery Department of Yunnan Diannan Central Hospital (The First People\u0026apos;s Hospital of Honghe state) from 01/01/2015 to 30/09/2023. Patients were diagnosed\u0026nbsp;with intracranial aneurysms\u0026nbsp;(IAs)\u0026nbsp;through\u0026nbsp;digital subtraction angiography (DSA) (Canon INFX-9000C, Japan),\u0026nbsp;computed tomography angiography\u0026nbsp;(CTA) (Canon 320\u0026nbsp;Rows\u0026nbsp;CT Aquilion One, Japan), or\u0026nbsp;magnetic\u0026nbsp;resonance angiography (MRA) (3.0T magnetic resonance imaging,\u0026nbsp;GE Discovery MR750W, USA) examinations. The inclusion criteria were\u0026nbsp;as follows: ruptured\u0026nbsp;intracranial\u0026nbsp;aneurysm (RIAs) group (Figure 1) and\u0026nbsp;Hunt\u0026ndash;Hess score\u0026nbsp;ranging\u0026nbsp;from \u0026quot;1\u0026quot; to \u0026quot;5\u0026quot; based on the patient\u0026apos;s condition[11].\u0026nbsp;In the\u0026nbsp;Unruptured intracranial aneurysms\u0026nbsp;(UIAs)\u0026nbsp;group\u0026nbsp;(Figure 1), the Hut\u0026ndash;Hess score was 0. Exclusion criteria is provided (Figure 1). This retrospective study was approved by\u0026nbsp;the Medical Ethics Committee of\u0026nbsp;Yunnan Diannan Central Hospital (The First People\u0026apos;s Hospital of Honghe state) ((2024) YDNLSN0.97).\u003c/p\u003e\n\u003cp\u003eThe collected data included\u0026nbsp;sex, age, ethnicity, comorbid underlying disease, ratio of aneurysm height to neck width (AR), aneurysm size, Intracranial Aneurysm Morphology, Non‑compliant use of antihypertensive drugs (NUAD), blood glucose, admission Hunt\u0026ndash;Hess score, and Glasgow Outcome Scale (GOS) score at discharge. The treatment methods were determined based on the patient\u0026apos;s physical condition, imaging data, and choice of the patient and their family and were divided into interventional treatment and surgical clipping. Timely follow-up of head CT, CTA or MRA was conducted after surgery. The locations of\u0026nbsp;the\u0026nbsp;aneurysms included the anterior cerebral artery\u0026nbsp;(ACA), internal carotid artery (ICA), middle cerebral artery (MCA) and posterior circulation (PCA), which indicated that the ACA included the anterior communication and pericallum; the ICA included the ocular segment, posterior communication, bifurcation, and anterior choroidal artery; the MCA included the proximal, bifurcation, and distal segments; and the PCA included the basal bifurcation, basal trunk, superior cerebellum, anterior inferior cerebellum, posterior inferior cerebellum, vertebral artery, and posterior cerebral artery. In the UIAs group, the AR of the multiple aneurysms were averaged, whereas in the RIAs group, the AR of the responsible aneurysms were determined if bleeding was responsible, and if the AR of the responsible aneurysms were not determined, the AR of the multiple aneurysms were averaged. Multiple aneurysms were counted by location. If multiple aneurysms occurred at the same location, 1 was counted. The size of multiple aneurysms was calculated according to the actual number of aneurysms.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eTreatment method selection\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe choice between interventional treatment and surgical clipping treatment was mainly based on imaging data to maximize patient benefits. In addition, if both treatment methods were acceptable, the results tended to be based on the opinions of the patients and their families.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConcept of detection indicators\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe maximum diameter of the aneurysm was divided into small (\u0026lt;5 mm), medium\u0026nbsp;(5 mm \u0026le; diameter\u0026lt;15 mm), large (15 mm \u0026le; diameter\u0026lt;25 mm), and giant (diameter \u0026ge; 25 mm)[12, 13]. AR was defined as the ratio of aneurysm height to aneurysm neck width, where aneurysm height is defined as the vertical distance from the aneurysm neck plane to the farthest point of the aneurysm[14]. Blood blister-like aneurysm (BBA) has diagnostic criteria based on independent diagnosis by experienced neurosurgeons and radiologists[15]. Aneurysms with irregular morphological features (AIMF): Based on their morphological appearance, intracranial aneurysms were categorized into two subtypes: irregular (characterized by the presence of lobulation, blebs, or wall protrusions) and regular (devoid of these irregular morphological characteristics)\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOutcomes\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAt discharge, patients were scored using the Glasgow Outcome Scale (GOS). The scoring criteria were as follows: good recovery (5), moderate disability (4), severe disability (3), vegetative state (2), and death (1). The patients were divided into 2 outcome groups: a good outcome group, which was defined as independent (GOS scores, 4-5), and a poor outcome group, which was defined as dependent (GOS scores, 3-1)[16, 17]\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eStatistical methods\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eContinuous variables that followed a normal distribution are represented by x̄\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u0026plusmn;\u003cem\u003es\u003c/em\u003e, and independent sample t tests were used for comparisons between two groups. If the data did not follow a normal distribution, they were represented by M (median) (Q1, Q3), and comparisons between the two groups were conducted using the Mann‒Whitney U test. Categorical variables are expressed as frequencies and percentages, and comparisons of rates between two groups were performed using \u0026chi;2 tests. The AR, NUAD and AIMF data were subjected to logistic regression analysis to predict aneurysm rupture. An ROC curve model was used to evaluate the effectiveness of the AR in predicting IAs rupture. Differences were considered statistically significant at \u003cem\u003eP\u003c/em\u003e\u0026lt;0.05. Statistical analysis was performed via SPSS Statistics (version 23, IBM, USA). Images were generated via GraphPad Prism (version 8, GraphPad Software, USA). A two-sided \u003cem\u003ep\u0026nbsp;\u003c/em\u003evalue \u0026lt; 0.05 was considered to indicate statistical significance.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cem\u003eParticipant characteristics\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAmong the 628 patients with IAs, only 532 met the inclusion criteria (Figure 1). The study patients with IAs consisted of 262 (49.25%) males and 270 (50.75%) females.\u0026nbsp;The UIAs group included 93 (49.73%) males and 94 (50.27%) females (Table 1). The RIAs group included 169 (48.99%) males and 176 (51.01%) females (Table 1). In particular, the percentage of patients with hypertension and heart disease in the UIAs group was significantly greater than that in the RIAs group, and there was no significant difference in the percentage of patients with diabetes (Table 1). Fifty-one patients (27.27%) in the UIAs group were treated, including 44 patients (23.52%) who received intervention, 7 patients (3.74%) who received surgical clipping (Table 1), and 136 patients (72.73%) who were not treated at the Yunnan Diannan Central Hospital (The First People's Hospital of Honghe state) or who were abandoned by patients or their families. Two hundred and forty-three patients (70.43%) in the RIAs group were treated, including 155 patients (44.93%) of interventional treatment, 88 patients (25.51%) of surgical clipping and 101 patients (29.28%) who did not receive treatment at the same hospital or were abandoned by patients or their families (Table 1). The age group with the highest incidence of aneurysms was between 51 and 60 years (Figure\u0026nbsp;2A and B).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eOutcome Analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe GOS of the\u0026nbsp;UIAs group was significantly greater than that of the RIAs group (Table 1). The rate of\u0026nbsp;good outcomes\u0026nbsp;in\u0026nbsp;the\u0026nbsp;UIAs\u0026nbsp;group was significantly\u0026nbsp;greater\u0026nbsp;than that\u0026nbsp;in\u0026nbsp;the\u0026nbsp;RIAs\u0026nbsp;group (Figure 2C).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eCharacteristics of IAs\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eA total of 564 IAs (including 1 patient with multiple IAs) were found based on location, including 205 (36.35%) in the UIAs group and 359 (63.65%) in the RIAs group. The incidence of the ICA (74, 36.10%) in the UIAs\u0026nbsp;group was significantly\u0026nbsp;greater\u0026nbsp;than the incidence of the ICA (82, 22.84%) in the RIAs\u0026nbsp;group.\u0026nbsp;In contrast, the incidence rate of the ACA (36, 17.56%) in the UIAs\u0026nbsp;group was significantly lower than the incidence rate of the ACA\u0026nbsp;(102, 28.41%) in the RIAs\u0026nbsp;group (Table 2). There was no significant difference in the incidence rates of the MCA 69 (33.66%) and PCA 26 (12.68%) in the\u0026nbsp;UIAs group compared with the incidence rates of the MCA 141 (39.28%) and PCA 34 (9.47%) in the\u0026nbsp;RIAs group (Table 2). The\u0026nbsp;UIAs group had 231 aneurysms, whereas the RIAs group had 444 aneurysms (multiple aneurysms, each assessed by standard size). Only the RIAs group had one case of giant aneurysm, whereas the\u0026nbsp;UIAs group did not. There was no significant difference in the incidence of the ICA 3 (1.3%), ACA 1 (0.43%), MCA 5 (2.16%), or PCA 3 (1.3%) between the UIAs group and the RIAs group in terms of the ICA 4 (0.9%), ACA 2 (0.45%), MCA 4 (0.9%), and PCA 1 (0.23%) for the occurrence of large aneurysms. The occurrence of middle -sized aneurysms in the\u0026nbsp;ACA\u0026nbsp;(10,\u0026nbsp;4.33%) and MCA\u0026nbsp;(30,\u0026nbsp;12.99%) in the\u0026nbsp;UIAs\u0026nbsp;group was significantly lower than that in the\u0026nbsp;RIAs\u0026nbsp;group\u0026nbsp;(64,\u0026nbsp;14.41%) and MCA\u0026nbsp;(93,\u0026nbsp;20.95%)\u0026nbsp;in the ACA group\u0026nbsp;(Table 2). However, the incidence of the\u0026nbsp;ICA23 (9.96%) and PCA11 (4.76%) in the UIAs group was not significantly different from that in the RIAs group (ICA55 (12.39%) and PCA15 (3.38%)) (Table 2). The incidence of small aneurysms of the ICA in the two groups was significantly greater in the UIAs group (60, 25.97%) than in the RIAs group (40, 9.01%), while the incidence of the ACA in the UIAs group (26, 11.26%) was significantly lower than that in the RIAs group (80, 18.02%) (Table 2). The incidence rates of the MCA 44 (19.05%) and PCA 15 (6.49%) in the UIAs group were not significantly\u0026nbsp;different from those in the\u0026nbsp;RIAs group (MCA 66 (14.86%) and PCA 19 (4.28%)). The incidence of multiple aneurysms in the UIAs group (32 [17.11%]) was not significantly different from that in the RIAs group (61 [17.68%]) (Table 2). The incidence of BBA in UIAs\u0026nbsp;Group 7 (3.74%) was\u0026nbsp;significantly\u0026nbsp;lower than that in\u0026nbsp;RIAs\u0026nbsp;Group 31 (8.99%) (Table 2).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe\u0026nbsp;\u003c/em\u003e\u003cem\u003eability\u003c/em\u003e\u003cem\u003e\u0026nbsp;of\u0026nbsp;\u003c/em\u003e\u003cem\u003ethe\u0026nbsp;\u003c/em\u003e\u003cem\u003eAR\u0026nbsp;\u003c/em\u003e\u003cem\u003eto predict\u003c/em\u003e\u003cem\u003e\u0026nbsp;aneurysm rupture\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAR analysis\u0026nbsp;revealed that the risk of aneurysm rupture in different locations was significantly lower in the UIAs group than in the RIAs group. Logistic regression curves and ROC curves were used for the analysis of the two groups of ACA, ICA, MCA and PCA aneurysms. Logistic regression and ROC curve analysis of the AR data were conducted. Compared with that of the RIAs group, the AR of the UIAs group was significantly lower than that of the RIAs group (Table 2). The regression data showed β 0, β 1 and OR (Figure 2D and Figure 3A, C, E, G), and ROC curve analysis revealed that the area under the curve (AUC) was significant difference (Figure 3B, D, F, H).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePredictive value of other factors for aneurysm rupture\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAnalysis of additional risk factors for IAs rupture indicated that NUAD and AIMF were risk factors for such events in the high-altitude setting (Table 3).\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe characteristics of aneurysms in high altitudes are similar to those in lower altitudes, and the age characteristics are also consistent with those in the lower altitudes. The proportion of patients with hypertension and heart disease had a higher probability of going to the hospital for examination, so these patients had a higher detection rate of aneurysms in the UIAs group. The main reason was that patients with hypertension and heart disease often visit the hospital for examination, and the rate of cerebrovascular examination was greater than that in the RIAs group. The UIAs group had a high rate of hypertension and heart disease, and the location and size of the aneurysms were significantly different between the UIAs group and the RIAs group. AR serves as a critical predictor of rupture in intracranial aneurysms at distinct anatomical sites. Additional factors contributing to IAs rupture include NUAD and AIMF.\u003c/p\u003e \u003cp\u003eThe peak age of aneurysm onset in high altitude was similar to that reported at normal times, mainly in the 51\u0026ndash;60 years age group[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In this age group, it was important to check the brain blood and brain regularly. In the epidemic population, the incidence of aneurysms was slightly greater in women than in men, similar to that reported in Plains[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. According to the analysis of the current status of high-altitude aneurysm treatment, interventional surgery is relatively popular in high altitudes, and relatively few patients choose clipping surgery, which is in line with the current treatment methods. In addition, the proportion of UIAs patients who chose to stop treatment was relatively high. The main reason was that some patients and their families were asymptomatic at present or were afraid of surgical risks, so they chose to observe and follow up and then start treatment when they were at risk of rupture. A small number of patients and their families chose other hospitals for treatment. In the RIAs group, due to aneurysm rupture accompanied by SAH, most of the patients were in a dangerous condition when they came to the hospital, and more patients and their families chose hospitalization, while some patients and their families also chose to give up treatment. Patients who chose other hospital treatments or whose families considered serious illness were excluded from treatment. From the perspective of the arterial origin and aneurysm location, the ICA had a greater rate of aneurysm occurrence in the UIAs group, whereas the ACA had a greater rate of aneurysm occurrence in the RIAs group. According to this ratio, if a patient's unruptured aneurysm was located in the ICA, the patient should be prepared for treatment in advance because the aneurysm might rupture at any time. However, in terms of the size of the aneurysms themselves, there was no significant difference in the incidence of large aneurysm rupture between the two groups, whereas there were significant differences in the incidence of ruptured bleeding in different parts of the medium and small aneurysms between the two groups. There were differences in the ACA and MCA between medium-sized aneurysms and between the ICA and ACA between small-sized aneurysms. If patients with aneurysms of different sizes and different locations are at risk of rupture, further treatment can be administered early. Among patients with ruptured aneurysms in high-altitude areas, the incidence of BBAs (8.99%) was greater than that in low-altitude areas (0.3%-6.6%)[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], which might be related to the special hypoxic environment at high altitudes. AR has a good ability to predict aneurysm rupture in high altitudes, and many studies in plain areas have shown that AR could play a role in determining whether AR is a risk factor for aneurysm rupture. According to our logistic regression analysis, the ACA, ICA, MCA and PCA all had obvious predictive effects. AR has good ability to predict aneurysm rupture in high altitudes, and many studies in plain areas have shown that AR can play a role in determining whether AR is a risk factor for aneurysm rupture[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. According to our logistic regression analysis, the ACA, ICA, MCA and PCA all had obvious predictive effects. Moreover, a ROC curve was used to determine the sensitivity and specificity of the AR in different aneurysm locations, and the analysis revealed that the AR had an obvious predictive effect. Additional risk factors for predicting in IAs rupture included NUAD and AIMF. Specifically, NUAD defined as irregular intake of antihypertensive drugs induced blood pressure fluctuations, which elevated the risk of IAs rupture, consistent with findings from relevant studies[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Similarly, AIMF was another risk factor for IAs rupture, which was also in line with the results of previous research[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. An analysis of the patients\u0026rsquo; GOS, revealed that the UIAs group had a significantly better prognosis than did the RIAs group, and the Hunt\u0026ndash;Hess score at admission was also crucial. Given tha the admission Hunt\u0026ndash;Hess score of the UIAs group was \"0\", an effective GOS correlation could not be established. However, the Hunt\u0026ndash;Hess score at admission in the RIAs group was negatively correlated with the GOS score[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. The lower the Hunt\u0026ndash;Hess score is, the greater the GOS score at discharge and, the better the prognosis, and the more severe the neurological damage upon admission is, the greater the Hunt\u0026ndash;Hess score, and the worse the discharge prognosis.\u003c/p\u003e \u003cp\u003eBy analyzing the epidemic characteristics and treatment status of high-altitude aneurysms, as well as assessing the risk of rupture by AR, we can effectively grasp the development pattern and treatment of high-altitude aneurysms, providing assistance for the future understanding of high-altitude aneurysms.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eWe summarized the common locations and rupture-prone sites of IAs in high-altitude populations, as well as the risk factors contributing to IAs rupture. In patients with ruptured aneurysms, the incidence of ICA rupture was greater in patients with unruptured aneurysms, whereas the incidence of ACA rupture was greater in patients with ruptured aneurysms, and the risk of rupture of medium and small aneurysms was lower in the unruptured group. AR serves as a critical predictor of rupture in intracranial aneurysms at distinct anatomical sites. Additional factors contributing to IAS rupture include NUAD and AIMF.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eUIAs: Unruptured intracranial aneurysms, RIAs: Ruptured intracranial aneurysms, SAH: Subarachnoid hemorrhage, IAs: Intracranial aneurysms, DSA: Digital subtraction angiography, CTA: Computed tomography angiography, MRA: Magnetic resonance angiography, GOS: Glasgow Outcome Scale, AR: Ratio of aneurysm height to neck width, BBA: Blood blister-like aneurysm, ACA: Anterior cerebral artery, ICA: Internal carotid artery, MCA: Middle cerebral artery, PCA: Posterior circulation. NUAD: Non‑compliant use of antihypertensive drugs, AIMF: Aneurysms with irregular morphological features.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDisclosure statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo potential conflict of interest was reported by the author(s).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Grant No. XZ202201YD0028C from Central government funds for guiding local scientific and technological development.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of Data and Materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval\u003c/strong\u003e \u003cstrong\u003eand Consent to Participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was conducted in accordance with the Declaration of Helsinki.The Medical Ethics Committee of the First People's Hospital of Honghe State (Southern central hospital of yunnan province). All of the participants provided signed informed consent.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;L.W., C.L., and J. Z.conceptualized and designed the study. T.Z., Y.T., F.W., J.W., and L.W. were responsible for material preparation and data analysis.X.Z.; L.W. and J.W. drafted the original manuscript. All authors have read and approved the final manuscript for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe extend our deepest gratitude to all patients and their caregivers who participated in this study for their valuable contributions and patience. At the same time, we also appreciate the efforts of the participating doctors and other relevant personnel.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePavlos T, Ahmad S, Nikolaos M, Eric C P, Chrissa S, Leonardo R-C, et al. Aneurysm Formation, Growth, and Rupture: The Biology and Physics of Cerebral Aneurysms. World Neurosurg. 2019; 130. https://doi.org/10.1016/j.wneu.2019.07.093\u003c/li\u003e\n\u003cli\u003eKarhunen V, Bakker MK, Ruigrok YM, Gill D, Larsson SC. Modifiable Risk Factors for Intracranial Aneurysm and Aneurysmal Subarachnoid Hemorrhage: A Mendelian Randomization Study. J Am Heart Assoc. 2021; 10: e022277. https://doi.org/10.1161/jaha.121.022277\u003c/li\u003e\n\u003cli\u003eBakker MK, van der Spek RAA, van Rheenen W, Morel S, Bourcier R, Hostettler IC, et al. Genome-wide association study of intracranial aneurysms identifies 17 risk loci and genetic overlap with clinical risk factors. Nat Genet. 2020; 52: 1303-1313. https://doi.org/10.1038/s41588-020-00725-7\u003c/li\u003e\n\u003cli\u003eRabelo NN, Samaia da Silva Coelho AC, Telles JPM, Coelho G, de Souza CS, Tozetto-Mendoza TR, et al. Human herpesvirus DNA occurrence in intracranial aneurysmal wall: illustrative case. J Neurosurg Case Lessons. 2021; 2: Case21301. https://doi.org/10.3171/case21301\u003c/li\u003e\n\u003cli\u003eGriswold D, Fernandez L, Rubiano A. Traumatic Subarachnoid Hemorrhage: A Scoping Review. J Neurotrauma. 2022; 39: 35-48. https://doi.org/10.1089/neu.2021.0007\u003c/li\u003e\n\u003cli\u003eMacdonald R, Jaja B, Cusimano M, Etminan N, Hanggi D, Hasan D, et al. SAHIT Investigators--on the outcome of some subarachnoid hemorrhage clinical trials. Translational stroke research. 2013; 4: 286-296. https://doi.org/10.1007/s12975-012-0242-1\u003c/li\u003e\n\u003cli\u003eMallet RT, Burtscher J, Richalet JP, Millet GP, Burtscher M. Impact of High Altitude on Cardiovascular Health: Current Perspectives. Vasc Health Risk Manag. 2021; 17: 317-335. https://doi.org/10.2147/vhrm.s294121\u003c/li\u003e\n\u003cli\u003eBilo G, Caravita S, Torlasco C, Parati G. Blood pressure at high altitude: physiology and clinical implications. Kardiologia polska. 2019; 77: 596-603. https://doi.org/10.33963/kp.14832\u003c/li\u003e\n\u003cli\u003eSilpanisong J, Pearce WJ. Vasotrophic regulation of age-dependent hypoxic cerebrovascular remodeling. Curr Vasc Pharmacol. 2013; 11: 544-563. https://doi.org/10.2174/1570161111311050002\u003c/li\u003e\n\u003cli\u003eKaminogo M, Yonekura M, Shibata S. Incidence and outcome of multiple intracranial aneurysms in a defined population. Stroke. 2003; 34: 16-21. https://doi.org/10.1161/01.str.0000046763.48330.ad\u003c/li\u003e\n\u003cli\u003eYifan Y, Seidu A R, Zhigang L. The impact of residual hematoma after evacuation on the outcomes of patients with ruptured intracranial aneurysms with intracerebral hematoma: A longitudinal single-center observational study. Medicine (Baltimore). 2022; 101. https://doi.org/10.1097/md.0000000000030129\u003c/li\u003e\n\u003cli\u003eWei Z, Peixi L, Yanlong T, Yuxiang G, Bin X, Liang C, et al. Complex middle cerebral artery aneurysms: a new classification based on the angioarchitecture and surgical strategies. Acta Neurochir (Wien). 2013; 155. https://doi.org/10.1007/s00701-013-1751-8\u003c/li\u003e\n\u003cli\u003eWang L, He W, Zhang H, Wang S, Zhao Y, Tian F, et al. Comparison of transcranial color Doppler sonography without and with contrast enhancement for detection and characterization of intracranial aneurysms. Journal of clinical ultrasound : JCU. 2012; 40: 535-539. https://doi.org/10.1002/jcu.21911\u003c/li\u003e\n\u003cli\u003eYin JH, Su SX, Zhang X, Bi YM, Duan CZ, Huang WM, et al. U-Shaped Association of Aspect Ratio and Single Intracranial Aneurysm Rupture in Chinese Patients: A Cross-Sectional Study. Front Neurol. 2021; 12: 731129. https://doi.org/10.3389/fneur.2021.731129\u003c/li\u003e\n\u003cli\u003eXiao-Dong Z, Peng H, Chuan H, Yue-Shan F, Gui-Lin L, Hong-Qi Z. Current Knowledge of and Perspectives about the Pathogenesis of Blood Blister-like Aneurysms of the Internal Carotid Artery: A Review of the Literature. Int J Med Sci. 2021; 18. https://doi.org/10.7150/ijms.53154\u003c/li\u003e\n\u003cli\u003eChen DY, Wu PF, Zhu XY, Zhao WB, Shao SF, Xie JR, et al. Risk factors and predictive model of cerebral edema after road traffic accidents-related traumatic brain injury. Chin J Traumatol. 2024. https://doi.org/10.1016/j.cjtee.2024.02.001\u003c/li\u003e\n\u003cli\u003eLinjie W, Chi L, Xingsen X, Shiju J, Yalan D, Li P, et al. The Effect of Hemoglobin Concentration on Hyperbaric Oxygen and Non-hyperbaric Oxygen in the Treatment of Hypertensive Intracerebral Hemorrhage After Operation at the High Altitude. Front Hum Neurosci. 2022; 16. https://doi.org/10.3389/fnhum.2022.834427\u003c/li\u003e\n\u003cli\u003eClaassen J, Park S. Spontaneous subarachnoid haemorrhage. Lancet. 2022; 400: 846-862. https://doi.org/10.1016/s0140-6736(22)00938-2\u003c/li\u003e\n\u003cli\u003eKrzyżewski RM, Kliś KM, Kucala R, Polak J, Kwinta BM, Starowicz-Filip A, et al. Intracranial aneurysm distribution and characteristics according to gender. Br J Neurosurg. 2018; 32: 541-543. https://doi.org/10.1080/02688697.2018.1518514\u003c/li\u003e\n\u003cli\u003eSook Young S, Yong Sam S, Kyung Gi C, Sun Yong K, Se Hyuk K, Young Hwan A, et al. Blood blister-like aneurysms at nonbranching sites of the internal carotid artery. J Neurosurg. 2006; 105. https://doi.org/10.3171/jns.2006.105.3.400\u003c/li\u003e\n\u003cli\u003eGeoffrey W P, Christopher A S, Ramesh G. Endovascular treatment of blister aneurysms. Neurosurg Focus. 2017; 42. https://doi.org/10.3171/2017.3.focus1751\u003c/li\u003e\n\u003cli\u003eLombarski L, Kunert P, Tarka S, Piechna A, Kujawski S, Marchel A. Unruptured intracranial aneurysms: relation between morphology and wall strength. Neurologia i neurochirurgia polska. 2022; 56: 410-416. https://doi.org/10.5603/PJNNS.a2022.0053\u003c/li\u003e\n\u003cli\u003eMa P, Li Y, Feng Y, Wu G, Li B, Wu H. The Application of Multiple Magnetic Resonance Scanning Techniques in Evaluating the Stability of Intracranial Aneurysms. International journal of general medicine. 2023; 16: 2003-2011. https://doi.org/10.2147/ijgm.s402255\u003c/li\u003e\n\u003cli\u003eZhong P, Lu Z, Li Z, Li T, Lan Q, Liu J, et al. Impact of premorbid hypertension and renin-angiotensin-aldosterone system inhibitors on the severity of aneurysmal subarachnoid haemorrhage: a multicentre study. Stroke Vasc Neurol. 2025; 10. https://doi.org/10.1136/svn-2023-003052\u003c/li\u003e\n\u003cli\u003eC C, A R. Neurological and psychosocial outcome after subarachnoid haemorrhage, and the hunt and hess scale as a predictor of clinical outcome. Zentralbl Neurochir. 2005; 66. https://doi.org/10.1055/s-2005-836477\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 3 are available in the supplementary files section\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Intracranial aneurysms, Epidemiological features, High altitude, Aneurysm rupture, Risk","lastPublishedDoi":"10.21203/rs.3.rs-9608513/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9608513/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThis study aimed to explore the epidemiology, treatment approaches, and rupture risk factors of high-altitude IAs.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003ePatients in the UIAs and RIAs groups were analyzed retrospectively. Statistical analysis of aneurysm incidence, location, and size was conducted between the two groups. Logistic regression and ROC curve analyses were then used to identify the AR (height/neck width ratio) and assess NUAD (Non‑compliant use of antihypertensive drugs) and AIMF (Aneurysms with irregular morphological features) as risk factors for IAs rupture. Finally, the patient's discharge Glasgow Outcome Scale (GOS) score was calculated to evaluate the rate of good outcomes.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe incidence of ICA (36.10%) in the UIAs group was significantly greater than the incidence of ICA (22.84%) in the RIAs group. The incidence of ACA (17.56%) in the UIAs group was significantly lower than the incidence of ACA (28.41%) in the RIAs group. The occurrence of medium-sized aneurysms in the ACA (4.33%) and MCA (12.99%) in the UIAs group was significantly lower than that in the RIAs group (14.41%) and MCA group (20.95%). The GOS was significantly higher in the UIAs group than in the RIAs group. Regression data showed AR, NUAD and AIMF prediction was valid respectively.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThe incidence of ACA rupture was greater in patients with ruptured aneurysms, and the risk of rupture of medium and small aneurysms was lower in the UIAs group. AR served as a critical predictor of rupture in IAs at distinct anatomical sites. Additional factors contributing to IAs rupture included NUAD and AIMF.\u003c/p\u003e","manuscriptTitle":"Aneurysms in High-Altitude Populations: Epidemiology, Management, and Rupture Risk","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-15 09:38:35","doi":"10.21203/rs.3.rs-9608513/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"06de01c2-bb31-4753-a371-45481a6219a1","owner":[],"postedDate":"May 15th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-19T08:46:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-18T11:00:16+00:00","index":70,"fulltext":""},{"type":"reviewerAgreed","content":"24693952745917823821349593384943663953","date":"2026-05-08T07:28:51+00:00","index":66,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-06T11:08:49+00:00","index":59,"fulltext":""},{"type":"reviewerAgreed","content":"308469995219028913764415630222657723065","date":"2026-05-06T10:59:27+00:00","index":58,"fulltext":""},{"type":"reviewerAgreed","content":"305933818659156180664410466188640787012","date":"2026-05-06T07:58:54+00:00","index":55,"fulltext":""},{"type":"reviewersInvited","content":"50","date":"2026-05-06T07:22:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-05-05T00:04:00+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-05-05T00:03:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Chinese Neurosurgical Journal","date":"2026-05-04T12:30:19+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-19T08:56:03+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-15 09:38:35","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9608513","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9608513","identity":"rs-9608513","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}