Declining trend in the estimated annual rupture rate of unruptured cerebral aneurysms in Japan: a nationwide study.

The incidence of subarachnoid hemorrhages (SAHs) in Japan has recently decreased. However, trends in the annual rates of unruptured cerebral aneurysms (UCAs) are unclear because calculations based on follow-up periods are limited to patients with ruptured cerebral aneurysms. We aimed to clarify current trends in the estimated annual rupture rates of UCAs in Japan and to identify the most relevant contributing factors. We analyzed data from the Japanese Ministry of Health, Labour and Welfare and records of the Japan Neurosurgical Society. The estimated annual rupture rates of UCAs between 2003 and 2018 were calculated according to age-adjusted mortality rates of SAH and number of treated ruptured cerebral aneurysms (RCAs). We estimated trends in annual rupture rates using sensitivity analysis and assessed associations between estimated annual rupture rates and the prevalences of hypertension and current smoking. The estimated annual rupture rate of UCAs significantly decreased from 1.44 to 0.87% and from 0.92 to 0.76%, respectively, in terms of age-adjusted mortality rates of SAH and number of treated RCAs (p < 0.001). The range of changes in estimated annual rupture rates of UCAs was - 1.13%‒0.83%, representing a declining UCA trend of 88%. The estimated annual rupture rates of UCAs declined by 0.02-0.10% and 0.01-0.05% with every percent decrease in hypertension and current smoking prevalence, respectively. The estimated annual rupture rate of UCAs has recently decreased in Japan, possibly due to a decrease in the prevalence of hypertension rather than smoking.

Relationship Between Brain Tumors and Intracranial Aneurysms: A Systematic Review.

AIM: To investigate the possible relationship between intracranial aneurysms and brain neoplasms. MATERIAL AND METHODS: A comprehensive literature review involving a search of the databases PubMed and Embase to identify relevant articles was conducted in March 2021. The initial search retrieved 451 articles. After deduplication and screening of abstracts, 56 articles were selected. After reading of the full texts, 19 articles were included in the review. RESULTS: There insufficient evidence to support that people with brain neoplasms have a higher incidence rate of IAs. However, the prevalence of IAs appears to be higher in patients with pituitary tumors than in the general population. The key factors affecting prognosis were tumor type in patients with unruptured aneurysms and progression of subarachnoid hemorrhage in individuals with ruptured aneurysms. Treatment should be individualized according to patient age, tumor pathology, location, and aneurysm rupture risk. CONCLUSION: There is a lack of evidence to affirm that the existence of brain neoplasm plays a role in the formation and rupture of intracranial aneurysms. Additionally, there is insufficient evidence to confirm a greater prevalence of intracranial aneurysms in individuals with brain tumors. The association of these two disorders does not appear to worsen patient outcome. Prognosis depends on tumor pathology for malignant cases and on subarachnoid hemorrhage in patients with ruptured aneurysms.

Trends in incidence and treatments of spontaneous subarachnoid hemorrhage- a 10 year hospital based study.

BACKGROUND: Improved endovascular methods make it possible to treat complex ruptured aneurysms, but surgery is still needed in certain cases. We evaluated the effects on the clinical results of the changes in aneurysm treatment. METHODS: The study cohort was 837 patients with spontaneous subarachnoid hemorrhage (SAH) and one or multiple aneurysms, admitted to Dept of Neurosurgery, Uppsala University Hospital from 2012 to 2021. Demography, location and treatment of aneurysms, neurologic condition at admission and discharge, mortality and last tier treatment of high intracranial pressure (ICP) was evaluated. Functional outcome was measured using the Extended Glasgow Outcome Scale (GOSE) Data concerning national incidences of stroke diseases was collected from open Swedish databases. RESULTS: Endovascular methods were used in 666 cases (79.6%). In 111 (13.3%) with stents. Surgery was performed in 115 cases (13.7%) and 56 patients (6.7%) had no aneurysm treatment. The indications for surgery were a hematoma (51 cases, 44.3%), endovascular treatment not considered safe (47 cases, 40.9%), or had been attempted without success (13 cases, 11.3%). Treatment with stent devices increased, and with surgery decreased over time. There was a trend in decrease in hemicraniectomias over time. Both the patient group admitted awake (n = 681) and unconscious (n = 156) improved significantly in consciousness between admission and discharge. Favorable outcome (GOSE 5-8) was seen in 69% for patients admitted in Hunt & Hess I-II and 25% for Hunt & Hess III-V. Mortality at one year was 10.9% and 42.7% for those admitted awake and unconscious, respectively.The number of cases decreased during the study period, which was in line with Swedish national data. CONCLUSIONS: The incidence of patients with SAH gradually decreased in our material, in line with national data. The treatment policy in our unit has been shifting to more use of endovascular methods. During the study period the use of hemicraniectomies decreased.

Subdural Hygroma After Management of Ruptured Intracranial Aneurysms: Incidence, Associated Factors, Clinical Course, and Management Options.

OBJECTIVE: To evaluate the incidence, associated factors, clinical course, and management options of subdural hygroma in patients treated for aneurysmal subarachnoid hemorrhage (aSAH). METHODS: From January 2013 until June 2022, 336 consecutive patients with aSAH underwent treatment in our center. No one patient was excluded from the study cohort. Computed tomography (CT) examinations were performed at admission, immediately after surgery and on the first postoperative day, and subsequently in case of any neurologic deterioration or, at least, once per week until discharge from the hospital. Thereafter, CT examinations were at the discretion of specialists in the rehabilitation facility, referring physicians, or neurosurgeons at the outpatient clinic. RESULTS: The length of radiologic follow-up starting from CT at admission ranged from 1 to 3286 days (mean, 673 ± 895 days; median, 150 days). Subdural hygromas developed in 84 patients (25%). An average interval until this imaging finding from the initial CT examination was 25 ± 55 days (median, 8 days; range, 0-362 days). Evaluation in the multivariate model showed that patient age ≥72 years (P < 0.0001), cerebrospinal fluid (CSF) shunting (P < 0.0001), and microsurgical clipping of ruptured intracranial aneurysm (RIA; P < 0.0001) are independently associated with the development of subdural hygroma. In 54 of 84 cases (64%), subdural hygromas required observation only. Increase of the lesion size with (5 cases) or without (10 cases) appearance of midline shift was associated with patient age <72 years (P = 0.0398), decompressive craniotomy (P = 0.0192), and CSF shunting (P = 0.0009), whereas evaluation of these factors in the multivariate model confirmed independent association of only CSF shunting (P = 0.0003). Active management of subdural hygromas included adjustment of the shunt programmable valve opening pressure, cranioplasty, external subdural drainage, or their combination. Overall, during follow-up (mean, 531 ± 824 days; median, 119 days; range, 2-3285 days) after the start of observation or applied treatment, subdural hygromas showed either decrease (50 cases) or stabilization (34 cases) of their sizes, and no one lesion showed progression again. CONCLUSIONS: The clinical course of subdural hygromas in patients treated for aSAH is generally favorable, but occasionally these lesions show progressive enlargement with or without the appearance of midline shift, which requires active management.

Unruptured untreated intracranial aneurysms: a retrospective analysis of outcomes of 445 aneurysms managed conservatively.

BACKGROUND: Factors predicting the growth or rupture of unruptured intracranial aneurysms (UIAs) remain under debate. Increased availability of neuro-imaging has led to increasing incidental findings, therefore understanding the natural history is vital to make appropriate management and follow-up decisions. We analysed a large dataset of UIAs to better identify patients at increased risk, therefore requiring enhanced monitoring and/or prophylactic intervention. METHODS: Electronic patient records were reviewed from consecutive patients regarding the following data: baseline demographics; past medical and smoking history; indication for imaging detecting the UIA(s); size, location and morphology of UIA(s), duration of imaging follow-up, detection of growth and rupture. Logistic regression was used to identify risk factors for UIA growth or rupture. Subgroup analysis was performed for 'small' aneurysms (<7mm). RESULTS: 445 UIAs in 274 patients were analysed. Total imaging follow-up was 2268 aneurysm-years (median 3.8 years/UIA). 27 UIAs grew (1.2% annually), and 15 ruptured (0.46%). 70.1% of UIAs were detected incidentally. Mean aneurysm diameter was 4.1mm.Logistic regression identified age < 50, autosomal dominant polycystic kidney disease (ADPKD), hypertension and diameter > 7mm as significant risk factors for growth/rupture. Additionally, previous smoking compared to current smoking was a protective factor against growth or rupture, but no significant difference was seen when comparing current- with non-smokers. Small aneurysm subgroup analysis identified diameter > 5mm, age < 50, ADPKD, and ongoing smoking as risk factors. No significant difference was observed in risk between those with and without previous SAH. CONCLUSIONS: This study underlines the need for imaging surveillance of even small UIAs. Smoking is a modifiable risk factor for growth/rupture of pre-existing aneurysms, while ADPKD is a particularly strong risk factor.

Risks for Oculomotor Nerve Palsy and Time to Recovery After Surgical Clipping of Posterior Communicating Artery Aneurysms: A Multicenter Retrospective Cohort Study.

BACKGROUND: Aneurysms of the posterior communicating segment of carotid artery (PcomA) have a high risk of rupture; when these nonruptured aneurysms are associated with oculomotor nerve palsy (ONP), the risk of rupture increases compared with asymptomatic nonruptured PcomA. OBJECTIVE: To retrospectively analyze the risk factors involved in ONP secondary to PcomA aneurysm and to study the factors involved in the recovery time of ONP once it is established. METHODS: This was a retrospective study of patients from 10 neurosurgery centers from October 2008 to December 2020. We analyzed age at diagnosis, presence of compressive neuropathy of the oculomotor nerve, presence of aneurysm rupture, largest aneurysm diameter, aneurysm projection, smoking, hypertension, diabetes, time between diagnosis and surgical treatment, as well as the outcome. RESULTS: Approximately 1 in 5 patients (119/511 23.3%) with a PcomA presented with ONP. We found that patients with aneurysms measuring greater than or equal to 7.5 mm were 1.6 times more likely to have ONP than those with aneurysms smaller than 7.5 mm. In our study, the prevalence of smoking in the PcomA + ONP group was 57.76%, and we also found that smokers were 2.51 times more likely to develop ONP. A total of 80.7% showed some degree of improvement, and 45.4% showed complete improvement with a median recovery time of 90 days. CONCLUSION: This study showed that 80.7% of patients with PcomA aneurysms undergoing surgical treatment with aneurysm clipping showed some degree of improvement of the ONP, with a median time to recovery between 90 and 120 days.

Epidemiology of Subarachnoid Hemorrhage in Isolated Islands in Japan: A Population-based Study in the Miyako Islands.

The Miyako Islands (with a population of approximately 50,000) are located in southwestern Japan, with a subtropical oceanic climate. This isolated location permitted a retrospective population-based epidemiological study of subarachnoid hemorrhage. We retrospectively enrolled 110 consecutive patients from 2010 to 2019 using the subarachnoid hemorrhage database at Okinawa Miyako Hospital, which is the only local facility with neurosurgeons. We calculated the incidence of subarachnoid hemorrhage standardized to the entire Japanese population. The seasonal distribution of subarachnoid hemorrhage onset and patients' epidemiological characteristics were also investigated. The standardized annual incidence of subarachnoid hemorrhage was 21.4 per 100,000 population, as reported previously in Japan. The patients' mean age was 62.1 ± 15.4 years, and women constituted 60.9%. Anterior communicating artery aneurysms were most common. The endovascular treatment for ruptured aneurysms was increasing as standard levels in Japan. The rates of symptomatic vasospasm and secondary hydrocephalus requiring additional neurosurgical treatment were 2.7% and 19.1%, respectively. The mortality rate was 23.6%. The percentage of patients with a modified Rankin scale score of 0-2 at discharge was 55.5%. There were no differences in the frequency of subarachnoid hemorrhage associated with seasonal distribution or climatic factors. The incidence, baseline characteristics, and clinical outcomes of subarachnoid hemorrhage in the Miyako Islands were similar to those in other regions of Japan. There are preferable epidemiological backgrounds for further practical clinical research.

Effect of combined fenestration of lamina terminalis and Liliequist membrane during surgical clipping on the incidence of chronic hydrocephalus in patients with anterior circulation ruptured aneurysms.

PURPOSE: To explore the effects of combined fenestration of lamina terminalis and Liliequist membrane during surgical clipping on the occurrence of chronic hydrocephalus in patients with ruptured anterior circulation aneurysm. METHODS: Clinical data of 78 patients with anterior circulation ruptured aneurysms who were treated between June 2018 and January 2021 were retrospectively analyzed. Based on the surgical treatment, patients were divided into 3 groups: clipping group (26 cases); fenestration group (lamina terminalis fenestration combined with clipping, 28 cases); and combination group (lamina terminalis fenestration and Liliequist membrane opening combined with clipping, 24 cases). The incidence of postoperative chronic hydrocephalus, the postoperative hydrocephalus shunt rate, and the Glasgow prognostic score (GOS) were evaluated. RESULTS: The incidence of postoperative chronic hydrocephalus in the combined group (16.6 %, 4/24) was significantly lower than that in the clipping group (46.1 %, 12/26) and the fenestration group (35.7 %, 10/28; P < 0.05). The shunt rate of chronic hydrocephalus in the combined group (4.1 %, 1/24) was significantly lower than that in the clipping group (30.7 %, 8/26) and the fenestration group (17.8 %, 5/28; P < 0.05). The rate of postoperative GOS score of 5 in the combined group (75.0 %, 18/24) was significantly higher than that in the clipping group (23.0 %, 6/26) and the fenestration group (57.1 %, 16/28; P < 0.05). CONCLUSION: Aneurysm clipping combined with lamina terminalis fenestration and Liliequist membrane opening can reduce the occurrence of chronic hydrocephalus and the rate of chronic hydrocephalus shunt surgery, thereby improving the prognosis of patients.

Risk factors for aneurysm rupture among Kazakhs: findings from a national tertiary.

BACKGROUND: Rupture of intracranial aneurysms (RIA) leads to subarachnoid hemorrhage (SAH) with severe consequences. Although risks for RIA are established, the results vary between ethnic groups and were never studied in Kazakhstan. This study aimed to establish the risk factors of RIA in the Kazakh population.  METHODS: Retrospective analysis of 762 patients with single IAs, who attended the neurosurgical center from 2008 until 2018, was conducted. Demographic characteristics, such as age, sex, smoking status, and hypertension were considered. Descriptive and bivariate analyses were performed. A multivariable logistic regression model was built to identify factors correlated with RIA. RESULTS: The mean age of participants was 48.49 ± 0.44 years old. The majority (68.37%) of IAs have ruptured. Of the ruptured aneurysms, 43.76% were < 6 mm, and 38.39% were located on the anterior cerebral and anterior communicating arteries (ACA). Logistic regression model indicates younger age group (16-40 years), smoking, having stage 3 hypertension, smaller IA size and its location on ACA increase the odds of rupture. CONCLUSIONS: This study has revealed that younger, smoking patients with stage 3 arterial hypertension are at higher risk for RIA. Small aneurysms (< 6 mm) and location on ACA had increased odds of rupture, while larger aneurysms on internal carotid arteries had lower odds.

Cotinine levels influence the risk of rupture of brain aneurysms.

Cotinine, the primary metabolite of nicotine, is currently regarded as the best biomarker of tobacco smoke exposure. We aim to assess whether cotinine levels are associated with (1) intracranial aneurysm and (2) intracranial aneurysm rupture. METHODS: We performed a single-center case-control study. Cases were consecutive patients admitted with diagnosis of brain aneurysm (ruptured or unruptured). We randomly selected controls without intracranial aneurysm from the same source population that produced the cases. Smoking data were collected by questionnaire, and serum levels of cotinine were used as an objective measure of nicotine exposure. Logistic regression models were used to assess the relationship between cotinine levels and aneurysm rupture. RESULTS: We included 86 patients with intracranial aneurysm and 96 controls. Smoking status (p < .001), cotinine levels (p = .009), and female sex (p = .006) were associated with diagnosis of intracranial aneurysm. In the multivariate analysis, controlling for sex, smoker status and age, levels of cotinine were independently associated with aneurysm rupture (OR 1.53, 95% CI 1.10-2.13, p = .012). CONCLUSIONS: Our results suggest that high cotinine levels in smokers with brain aneurysm are significantly associated with high rupture risk, independently of smoker status, age, and sex.

Trends in Admissions and Outcomes for Treatment of Aneurysmal Subarachnoid Hemorrhage in the United States.

BACKGROUND: Lifestyle modifications and advances in surgical and endovascular techniques for treating unruptured intracranial aneurysm (UIA) have vastly evolved over the last few decades and may have reduced the incidence of aneurysmal subarachnoid hemorrhage (aSAH). However, the actual impact of these changes on the rates and outcomes of aSAH remain unexplored. Thus, we studied national aSAH admissions and outcome trends and changes of major risk factors over time. METHODS: We queried the National Inpatient Sample between 2006 and 2018 to identify adult patients admitted and treated for UIA or ruptured aneurysm with aSAH. The Cochran-Armitage test was conducted to assess the linear trend of proportion of prevalence, inpatient mortality, hypertension, and current smoking status among aSAH admissions. Multivariable logistic regression was conducted to assess the odds of presenting with aSAH versus UIA, in addition to the odds of inpatient mortality among patients with aSAH. RESULTS: A total of 159,913 patients presented with UIA and 133,567 presented with aSAH. Admissions for aSAH decreased by 0.97% (p < 0.001) per year. Current smoking and hypertension were associated with higher odds of being admitted for aSAH compared with the treatment for UIA (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.29-1.48; OR 1.15, 95% CI 1.08-1.22, respectively). Compared with White patients, Black patients (OR 1.32, 95% CI 1.21-1.43), Hispanic patients (OR 1.38, 95% CI 1.25-1.52), and patients of other races and/or ethnicities (OR 1.73, 95% CI 1.54-1.95) had a higher chance of presenting with aSAH. Rates of inpatient mortality among aSAH admissions showed no change over time (p = 0.21). Among patients admitted with aSAH, current smoking and hypertension showed an upward trend of 0.58% (p < 0.001) and 1.60% (p < 0.001) per year, respectively. CONCLUSIONS: Despite a downward trend in the annual frequency of hospitalizations for aSAH, inpatient mortality rates for patients undergoing treatment of the ruptured aneurysm have remained unchanged in the United States. Smoking and hypertension are increasingly prevalent among patients with aSAH. Thus, efforts to control these modifiable risk factors must be further strengthened.

Studies Related to Ruptured Abdominal Aortic Aneurysms in the Past 10 Years (2011-2020): A Bibliometric Analysis.

BACKGROUND Ruptured abdominal aortic aneurysms have been a topic of common global interest for the past 20 years, with a steadily increasing number of publications. The purpose of this study was to explore the research themes and the current status of the last 10 years through a bibliometric analysis of the publications in this field. MATERIAL AND METHODS We performed a literature search for ruptured abdominal aortic aneurysms using the Web of Science Core Collection on November 14, 2021 and performed a bibliometric analysis and visualization of the results of the publications using the R-Bibliometrix package and VOSviewer software. RESULTS From 2011 to 2020, 2381 publications were retrieved, including 2073 articles and 308 reviews. The United States had the highest number of publications and has made a large contribution to the field. Jonathan Golledge is an important researcher with the highest number of publications. Journal of Vascular Surgery is ranked first in terms of the number of publications and local citations. Mortality and outcomes, repair treatment, and risk factors are the 3 main focuses in the field, followed by intraluminal thrombus and molecular expression. CONCLUSIONS Our bibliometric analysis suggests mainstream research is focused on clinical studies related to the surgical approach and its prognosis and on pathological mechanisms and hemodynamic studies related to risk factors for abdominal aortic aneurysms rupture. There are many other opportunities for future research in the clinical joint basis of abdominal aortic aneurysms rupture.

Comparison of the unruptured intracranial aneurysm treatment score recommendations with clinical treatment results - A series of 322 aneurysms.

Intracranial aneurysms occur with a prevalence of 3-5 %. Subarachnoid hemorrhage (SAH) due to aneurysm rupture is a rare but possibly fatal complication, so that occlusion of unruptured intracranial aneurysms (UIA) must be considered. The Unruptured Intracranial Aneurysm Treatment Score (UIATS) offers support for clinical decision making and has been shown to correlate with real life decisions in clinical practice. However, there is no data concerning the correlation of patient outcome and UIATS. Patients presenting to our outpatient clinic between January 1st, 2014 and December 31st, 2017 were retrospectively analyzed. We recorded the Extended Glasgow Outcome Scale (GOS-E) for longest possible follow-up, the choice of treatment, complications and UIATS recommendation. We included 221 patients with 322 UIA. 124 (38.5 %) UIA were observed and 198 (61.5 %) were occluded, of which 62 (31.3 %) underwent open surgery and 136 (68.7 %) were treated endovascularly. Spearman's rank correlation between our treatment choice and conclusive UIATS recommendation was 0.362 (p < 0.001). If UIATS was inconclusive, there were significantly more treatment-associated deteriorations (10/66 versus 7/132, p = 0.020). Otherwise, UIATS was not significantly associated with outcome. Therefore, treatment choice for UIA remains an individual decision. However, inconclusive UIATS must trigger vigilance and may be a negative prognostic marker for complications.

Sex Difference and Rupture Rate of Intracranial Aneurysms: An Individual Patient Data Meta-Analysis.

BACKGROUND AND PURPOSE: In previous studies, women had a higher risk of rupture of intracranial aneurysms than men, but female sex was not an independent risk factor. This may be explained by a higher prevalence of patient- or aneurysm-related risk factors for rupture in women than in men or by insufficient power of previous studies. We assessed sex differences in rupture rate taking into account other patient- and aneurysm-related risk factors for aneurysmal rupture. METHODS: We searched Embase and Pubmed for articles published until December 1, 2020. Cohorts with available individual patient data were included in our meta-analysis. We compared rupture rates of women versus men using a Cox proportional hazard regression model adjusted for the PHASES score (Population, Hypertension, Age, Size of Aneurysm, Earlier Subarachnoid Hemorrhage From Another Aneurysm, Site of Aneurysm), smoking, and a positive family history of aneurysmal subarachnoid hemorrhage. RESULTS: We pooled individual patient data from 9 cohorts totaling 9940 patients (6555 women, 66%) with 12 193 unruptured intracranial aneurysms, and 24 357 person-years follow-up. Rupture occurred in 163 women (rupture rate 1.04%/person-years [95% CI, 0.89-1.21]) and 63 men (rupture rate 0.74%/person-years [95% CI, 0.58-0.94]). Women were older (61.9 versus 59.5 years), were less often smokers (20% versus 44%), more often had internal carotid artery aneurysms (24% versus 17%), and larger sized aneurysms (≥7 mm, 24% versus 23%) than men. The unadjusted women-to-men hazard ratio was 1.43 (95% CI, 1.07-1.93) and the adjusted women/men ratio was 1.39 (95% CI, 1.02-1.90). CONCLUSIONS: Women have a higher risk of aneurysmal rupture than men and this sex difference is not explained by differences in patient- and aneurysm-related risk factors for aneurysmal rupture. Future studies should focus on the factors explaining the higher risk of aneurysmal rupture in women.

The relationship between staying up late and risk of intracranial aneurysm rupture: A single-center study.

OBJECTIVE: To evaluate the impact of staying up late (SUL) on the risk of intracranial aneurysm (IA) rupture. METHODS: This case-control study included 452 patients diagnosed with IA. They were divided into ruptured and unruptured groups. Staying up late was categorized in three levels (11-12 o'clock, 12-1 o'clock, after 1 o'clock) according to the time of falling asleep. To explore the relationship between staying up late and risk of IA rupture, univariate and multivariate logistic regression analyses were performed. RESULTS: Multivariate analysis found a significant difference in the percentage of patients falling asleep at 12-1 o'clock (OR, 2.25; 95% CI, 1.10-4.59) or after 1 o'clock (OR, 4.68; 95% CI, 1.74-12.55) between the ruptured and unruptured groups. The following risk factors differed significantly between the two groups: hypertension (OR, 2.05; 95% CI, 1.33-3.17), current smoking (OR, 1.72; 95% CI, 1.09-2.71), irregular IA (OR, 1.85; 95% CI, 1.15-3.00), IA size ≥8mm (OR, 1.92; 95% CI, 1.22-3.02), MCA location (OR, 2.45; 95% CI, 1.19-5.02), and aspect ratio (OR, 1.33; 95% CI, 1.02-1.73). CONCLUSION: Patients who fell asleep later than 12 midnight on average showed higher risk of IA rupture. The reasons for this are not very clear. A review of the literature suggests that this association may be related to a series of physiological, pathophysiological, endocrine and metabolic changes.

Shape related features of intracranial aneurysm are associated with rupture status in a large Chinese cohort.

BACKGROUND: To investigate the prevalence of small ruptured saccular intracranial aneurysms (sIA) in a Chinese cohort and to identify factors associated with rupture status of sIAs. METHODS: Consecutive patients with confirmed sIAs by DSA from January 2015 to July 2019 were included. Demographic and aneurysmal features, including maximal diameter, location, irregularity (lobulated or with blebs), and aspect ratio (AR, defined as height divided by neck width) were recorded and analyzed. Mixed effect logistic regression was used in multivariate analysis. RESULTS: We analyzed 1514 sIAs in a Chinese cohort of 1216 patients, including 651 ruptured and 863 unruptured sIAs. Median aneurysm size was 5.7 mm for ruptured aneurysms, with 66.1% <7 mm in maximal diameter, and 40.2% measuring <5 mm. The median PHASES score of ruptured sIAs was 5. In multivariate analysis, male sex, hypertension, locations other than the internal carotid artery, irregularity (lobulated or with blebs), and higher AR were independently associated with rupture status (OR for irregularity, 2.88, 95% CI 2.20 to 3.77, p<0.001; OR for AR, 1.12, 95% CI 1.01 to 1.24, p=0.036). However, maximal diameter was not significantly associated with rupture status (p=0.72). CONCLUSIONS: In this cohort, ruptured sIAs were frequently smaller than 7 mm. Shape related features, such as irregularity and higher AR, were associated with the ruptured status of sIAs, irrespective of diameter. PHASES seems to be inadequate in sIA risk stratification. Shape related parameters may be further investigated in prospective studies.

Prediction of bleb formation in intracranial aneurysms using machine learning models based on aneurysm hemodynamics, geometry, location, and patient population.

BACKGROUND: Bleb presence in intracranial aneurysms (IAs) is a known indication of instability and vulnerability. OBJECTIVE: To develop and evaluate predictive models of bleb development in IAs based on hemodynamics, geometry, anatomical location, and patient population. METHODS: Cross-sectional data (one time point) of 2395 IAs were used for training bleb formation models using machine learning (random forest, support vector machine, logistic regression, k-nearest neighbor, and bagging). Aneurysm hemodynamics and geometry were characterized using image-based computational fluid dynamics. A separate dataset with 266 aneurysms was used for model evaluation. Model performance was quantified by the area under the receiving operating characteristic curve (AUC), true positive rate (TPR), false positive rate (FPR), precision, and balanced accuracy. RESULTS: The final model retained 18 variables, including hemodynamic, geometrical, location, multiplicity, and morphology parameters, and patient population. Generally, strong and concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns together with larger, more elongated, and more distorted shapes were associated with bleb formation. The best performance on the validation set was achieved by the random forest model (AUC=0.82, TPR=91%, FPR=36%, misclassification error=27%). CONCLUSIONS: Based on the premise that aneurysm characteristics prior to bleb formation resemble those derived from vascular reconstructions with their blebs virtually removed, machine learning models can identify aneurysms prone to bleb development with good accuracy. Pending further validation with longitudinal data, these models may prove valuable for assessing the propensity of IAs to progress to vulnerable states and potentially rupturing.

Risk Factors for Cerebral Aneurysm Rupture in Mongolia.

PURPOSE: Identification of country-specific demographic, medical, lifestyle, and geoenvironmental risk factors for cerebral aneurysm rupture in the developing Asian country of Mongolia. First-time estimation of the crude national incidence of aneurysmal subarachnoid hemorrhage (aSAH). METHODS: A retrospective analysis of all intracranial digital subtraction angiographies (DSA) acquired in Mongolia during the 2­year period 2016-2017 (1714 examinations) was performed. During this period, DSA was used as primary diagnostic imaging modality for acute severe neurological symptoms in the sole hospital nationwide dedicated to neurological patients. The catchment area of the hospital included the whole country. Patients with incidental and ruptured aneurysms were reviewed with respect to their medical history and living conditions. The data was used to install a Mongolian aneurysm registry. RESULTS: The estimated annual crude incidence of cerebral aneurysm rupture was 6.71 for the country of Mongolia and 14.53 per 100,000 persons for the capital region of Ulaanbaatar. Risk factors common in developed countries also applied for the Mongolian population: A medical history of hypertension, smoking or the presence of multiple aneurysms led to a higher relative risk of rupture. In contrast, female gender was not associated with a higher risk in this national cohort. Males pursuing a traditional nomadic living may exhibit a specifically high risk of rupture. CONCLUSION: Disease management of over 200 individuals/year with aSAH constitutes a socioeconomic burden in Mongolia. Efforts to raise awareness of the risk factors hypertension and smoking among the Mongolian population are desirable. Measures to improve the nationwide availability of modern neurovascular treatment options are currently under consideration.

Difference in Rupture Risk Between Familial and Sporadic Intracranial Aneurysms: An Individual Patient Data Meta-analysis.

BACKGROUND AND OBJECTIVES: We combined individual patient data (IPD) from prospective cohorts of patients with unruptured intracranial aneurysms (UIAs) to assess to what extent patients with familial UIA have a higher rupture risk than those with sporadic UIA. METHODS: For this IPD meta-analysis, we performed an Embase and PubMed search for studies published up to December 1, 2020. We included studies that (1) had a prospective study design; (2) included 50 or more patients with UIA; (3) studied the natural course of UIA and risk factors for aneurysm rupture including family history for aneurysmal subarachnoid haemorrhage and UIA; and (4) had aneurysm rupture as an outcome. Cohorts with available IPD were included. All studies included patients with newly diagnosed UIA visiting one of the study centers. The primary outcome was aneurysmal rupture. Patients with polycystic kidney disease and moyamoya disease were excluded. We compared rupture rates of familial vs sporadic UIA using a Cox proportional hazard regression model adjusted for PHASES score and smoking. We performed 2 analyses: (1) only studies defining first-degree relatives as parents, children, and siblings and (2) all studies, including those in which first-degree relatives are defined as only parents and children, but not siblings. RESULTS: We pooled IPD from 8 cohorts with a low and moderate risk of bias. First-degree relatives were defined as parents, siblings, and children in 6 cohorts (29% Dutch, 55% Finnish, 15% Japanese), totaling 2,297 patients (17% familial, 399 patients) with 3,089 UIAs and 7,301 person-years follow-up. Rupture occurred in 10 familial cases (rupture rate: 0.89%/person-year; 95% confidence interval [CI] 0.45-1.59) and 41 sporadic cases (0.66%/person-year; 95% CI 0.48-0.89); adjusted hazard ratio (HR) for familial cases 2.56 (95% CI 1.18-5.56). After adding the 2 cohorts excluding siblings as first-degree relatives, resulting in 9,511 patients, the adjusted HR was 1.44 (95% CI 0.86-2.40). DISCUSSION: The risk of rupture of UIA is 2.5 times higher, with a range from a 1.2 to 5 times higher risk, in familial than in sporadic UIA. When assessing the risk of rupture in UIA, family history should be taken into account.

Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries.

BACKGROUND: Intracranial aneurysms are acquired abnormal vascular dilations. The most dangerous complication of a cerebral aneurysm is its rupture, with a high rate of mortality. This study aimed to determine whether there is an association between anatomic variations in the circle of Willis and ruptured aneurysms in the anterior and posterior communicating arteries. METHODS: A cross-sectional study of adult patients with a diagnosis of intracranial aneurysm was carried out between March 2015 and March 2019. The patients were divided into groups of ruptured or unruptured aneurysm in the anterior and posterior communicating arteries. RESULTS: A total of 132 patients with anterior and posterior communicating artery aneurysms were included. The presence of anatomic variation in the circle of Willis presented a statistically significant association with ruptured aneurysms (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.11-4.65; P = 0.024). There was a statistically significant difference between the presence of nonspherical aneurysm and rupture (OR, 6.9; 95% CI, 3.12-15.48; P < 0.0001). Multivariate logistic regression observed smoking (OR, 2.4; 95% CI, 1.01-5.9; P = 0.4), anterior complex variations (OR, 2.68; 95% CI, 1.01-7.18; P < 0.04), and nonspherical morphology (OR, 4.7; 95% CI, 1.93-11.45; P = 0.001) presented a statistically significant association with the rupture. CONCLUSIONS: Our results suggest that the studied variations of the circle of Willis and nonspherical morphology, in addition to playing a role in the development of cerebral aneurysms, may contribute to their rupture.