A proposed parent vessel geometry—based categorization of saccular intracranial aneurysms: computational flow dynamics analysis of the risk factors for lesion rupture

2005 ◽  
Vol 103 (4) ◽  
pp. 662-680 ◽  
Author(s):  
Tamer Hassan ◽  
Eugene V. Timofeev ◽  
Tsutomu Saito ◽  
Hiroaki Shimizu ◽  
Masayuki Ezura ◽  
...  
Keyword(s):  
Risk Factors ◽  
Intracranial Aneurysms ◽  
Aneurysm Rupture ◽  
Flow Dynamics ◽  
Low Flow ◽  
Parent Artery ◽  
Dynamics Analysis ◽  
Content Type ◽  
Computational Flow Dynamics ◽  
Fine Print

Object. The authors created a simple, broadly applicable classification of saccular intracranial aneurysms into three categories: sidewall (SW), sidewall with branching vessel (SWBV), and endwall (EW) according to the angiographically documented patterns of their parent arteries. Using computational flow dynamics analysis (CFDA) of simple models representing the three aneurysm categories, the authors analyzed geometry-related risk factors such as neck width, parent artery curvature, and angulation of the branching vessels. Methods. The authors performed CFDAs of 68 aneurysmal geometric formations documented on angiograms that had been obtained in patients with 45 ruptured and 23 unruptured lesions. In successfully studied CFDA cases, the wall shear stress, blood velocity, and pressure maps were examined and correlated with aneurysm rupture points. Statistical analysis of the cases involving aneurysm rupture revealed a statistically significant correlation between aneurysm depth and both neck size (p < 0.0001) and caliber of draining arteries (p < 0.0001). Wider-necked aneurysms or those with wider-caliber draining vessels were found to be high-flow lesions that tended to rupture at larger sizes. Smaller-necked aneurysms or those with smaller-caliber draining vessels were found to be low-flow lesions that tended to rupture at smaller sizes. The incidence of ruptured aneurysms with an aspect ratio (depth/neck) exceeding 1.6 was 100% in the SW and SWBV categories, whereas the incidence was only 28.75% for the EW aneurysms. Conclusions. The application of standardized categories enables the comparison of results for various aneurysms' geometric formations, thus assisting in their management. The proposed classification system may provide a promising means of understanding the natural history of saccular intracranial aneurysms.

Detachable balloon embolization therapy of posterior circulation intracranial aneurysms

1989 ◽  
Vol 71 (4) ◽  
pp. 512-519 ◽  
Author(s):  
Randall T. Higashida ◽  
Van V. Halbach ◽  
Leslie D. Cahan ◽  
Grant B. Hieshima ◽  
Yoshifumi Konishi
Keyword(s):  
Basilar Artery ◽  
Intracranial Aneurysms ◽  
Posterior Circulation ◽  
Parent Artery ◽  
Parent Vessel ◽  
Detachable Balloon ◽  
Content Type ◽  
Aneurysm Neck ◽  
Balloon Embolization ◽  
Fine Print

✓ Treatment of complex and surgically difficult intracranial aneurysms of the posterior circulation is now being performed with intravascular detachable balloon embolization techniques. The procedure is carried out under local anesthesia from a transfemoral arterial approach, which allows continuous neurological monitoring. Under fluoroscopic guidance, the balloon is propelled by blood flow through the intracranial circulation and, in most cases, can be guided directly into the aneurysm, thus preserving the parent vessel. If an aneurysm neck is not present, test occlusion of the parent vessel is performed and, if tolerated, the balloon is detached. Twenty-six aneurysms in 25 patients have been treated by this technique. The aneurysms have involved the distal vertebral artery (five cases), the mid-basilar artery (six cases), the distal basilar artery (11 cases), and the posterior cerebral artery (four cases). The aneurysms varied in size and included three small (< 12 mm), 15 large (12 to 25 mm), and eight giant (> 25 mm). Fifteen patients (60%) presented with hemorrhage and 10 patients (40%) with mass effect. In 17 cases (65%) direct balloon embolization of the aneurysm was achieved with preservation of the parent artery. In nine cases (35%), because of aneurysm location and size, occlusion of the parent vessel was performed. Complications from therapy included three cases of transient cerebral ischemia which resolved, three cases of stroke, and five deaths due to immediate or delayed aneurysm rupture. The follow-up period has ranged from 2 months to 43 months (mean 22.5 months). In cases where posterior circulation aneurysms have been difficult to treat by conventional neurosurgical techniques, intravascular detachable balloon embolization may offer an alternative therapeutic option.

Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture

2000 ◽  
Vol 93 (3) ◽  
pp. 379-387 ◽  
Author(s):  
Seppo Juvela ◽  
Matti Porras ◽  
Kristiina Poussa
Keyword(s):  
Risk Factors ◽  
Smoking Status ◽  
Significant Risk ◽  
Significant Risk Factor ◽  
Aneurysm Rupture ◽  
Content Type ◽  
Unruptured Aneurysms ◽  
Unruptured Intracranial Aneurysms ◽  
History Of ◽  
Fine Print

Object. The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed.Methods. One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using life-table analyses and Cox's proportional hazards regression models including time-dependent covariates.The median follow-up time was 19.7 years (range 0.8–38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1–1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93–1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04–2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21–7.66, p = 0.02).Conclusions. Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.

Role of apoptosis in intracranial aneurysm rupture

2004 ◽  
Vol 101 (6) ◽  
pp. 1018-1025 ◽  
Author(s):  
Luigi Pentimalli ◽  
Andrea Modesti ◽  
Andrea Vignati ◽  
Enrico Marchese ◽  
Alessio Albanese ◽  
...  
Keyword(s):  
Intracranial Aneurysms ◽  
Superficial Temporal Artery ◽  
Aneurysm Rupture ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Content Type ◽  
Unruptured Aneurysms ◽  
Ruptured Aneurysms ◽  
Aneurysm Wall ◽  
Unruptured Intracranial Aneurysms ◽  
Fine Print

Object. Mechanisms involved in the rupture of intracranial aneurysms remain unclear, and the literature on apoptosis in these lesions is extremely limited. The hypothesis that apoptosis may reduce aneurysm wall resistance, thus contributing to its rupture, warrants investigation. The authors in this study focused on the comparative evaluation of apoptosis in ruptured and unruptured intracranial aneurysms. Peripheral arteries in patients harboring the aneurysms and in a group of controls were also analyzed. Methods. Between September 1999 and February 2002, specimens from 27 intracranial aneurysms were studied. In 13 of these patients apoptosis was also evaluated in specimens of the middle meningeal artery (MMA) and the superficial temporal artery (STA). The terminal deoxynucleotidyl transferase—mediated deoxyuridine triphosphate nick-end labeling technique was used to study apoptosis via optical microscopy; electron microscopy evaluation was performed as well. Apoptotic cell levels were related to patient age and sex, aneurysm volume and shape, and surgical timing. Significant differences in apoptosis were observed when comparing ruptured and unruptured aneurysms. High levels of apoptosis were found in 88% of ruptured aneurysms and in only 10% of unruptured lesions (p < 0.001). Elevated apoptosis levels were also detected in all MMA and STA specimens obtained in patients harboring ruptured aneurysms, whereas absent or very low apoptosis levels were observed in MMA and STA specimens from patients with unruptured aneurysms. A significant correlation between aneurysm shape and apoptosis was found. Conclusions. In this series, aneurysm rupture appeared to be more related to elevated apoptosis levels than to the volume of the aneurysm sac. Data in this study could open the field to investigations clarifying the causes of aneurysm enlargement and rupture.

Combined surgical and endovascular techniques of flow alteration to treat fusiform and complex wide-necked intracranial aneurysms that are unsuitable for clipping or coil embolization

2001 ◽  
Vol 95 (1) ◽  
pp. 24-35 ◽  
Author(s):  
Brian L. Hoh ◽  
Christopher M. Putman ◽  
Ronald F. Budzik ◽  
Bob S. Carter ◽  
Christopher S. Ogilvy
Keyword(s):  
Intracranial Aneurysms ◽  
Massachusetts General Hospital ◽  
Treatment Strategies ◽  
Aneurysm Rupture ◽  
Morbidity Rate ◽  
Content Type ◽  
Flow Alteration ◽  
Fisher Grade ◽  
Number Of Patients ◽  
Fine Print

Object. Certain intracranial aneurysms, because of their fusiform or complex wide-necked structure, giant size, or involvement with critical perforating or branch vessels, are unamenable to direct surgical clipping or endovascular coil treatment. Management of such lesions requires alternative or novel treatment strategies. Proximal and distal occlusion (trapping) is the most effective strategy. In lesions that cannot be trapped, alteration in blood flow to the “inflow zone,” the site most vulnerable to aneurysm growth and rupture, is used. Methods. From 1991 to 1999 the combined neurosurgical—neuroendovascular team at the Massachusetts General Hospital (MGH) managed 48 intracranial aneurysms that could not be clipped or occluded. Intracavernous internal carotid artery aneurysms were excluded from this analysis. By applying a previously described aneurysm rupture risk classification system (MGH Grades 0–5) based on the age of the patient, aneurysm size, Hunt and Hess grade, Fisher grade, and whether the aneurysm was a giant lesion located in the posterior circulation, the authors found that a significant number of patients were at moderate risk (MGH Grade 2; 31.3% of patients) and at high risk (MGH Grades 3 or 4; 22.9%) for treatment-related morbidity. The lesions were treated using a variety of strategies—surgical, endovascular, or a combination of modalities. Aneurysms that could not be trapped or occluded were treated using a paradigm of flow alteration, with flow redirected from either native collateral networks or from a surgically performed vascular bypass. Overall clinical outcomes were determined using the Glasgow Outcome Scale (GOS). A GOS score of 5 or 4 was achieved in 77.1%, a GOS score of 3 or 2 in 8.3%, and death (GOS 1) occurred in 14.6% of the patients. Procedure-related complications occurred in 27.1% of cases; the major morbidity rate was 6.3% and the mortality rate was 10.4%. Three patients experienced aneurysmal hemorrhage posttreatment; in two patients this event proved to be fatal. Aneurysms with MGH Grades 0, 1, 2, 3, and 4 were associated with favorable outcomes (GOS scores of 5 or 4) in 100%, 92.8%, 71.4%, 50%, and 0% of instances, respectively. Conclusions. Despite a high incidence of transient complications, intracranial aneurysms that cannot be clipped or occluded require alternative surgical and endovascular treatment strategies. In those aneurysms that cannot safely be trapped or occluded, one approach is the treatment strategy of flow alteration.

Turbulence in human intracranial saccular aneurysms

1970 ◽  
Vol 33 (5) ◽  
pp. 485-497 ◽  
Author(s):  
Gary G. Ferguson
Keyword(s):  
Intracranial Aneurysms ◽  
Critical Reynolds Number ◽  
Vascular Tissue ◽  
Low Flow ◽  
Content Type ◽  
Structural Fatigue ◽  
Glass Model ◽  
The Mean ◽  
Fine Print ◽  
Saccular Aneurysms

✓ Preliminary experiments with glass model bifurcation aneurysms demonstrated that turbulent flow pattern occurs in the sac of an aneurysm at a low flow rate (critical Reynolds number, 400 ± 10 S.E.M.). A prediction that flow is turbulent in the sac of human intracranial saccular aneurysms was confirmed in a clinical study. Bruits, indicative of turbulence, were recorded with a phonocatheter from the sacs of 10 out of 17 intracranial aneurysms exposed at surgery where the mean arterial pressures were above 50 mm Hg. The amplitude of the bruits varied with the pressure. All of the patients in whom no bruit was found had profound Arfonad hypotension at the time of recording. Turbulence causes vibration in the wall of a vessel. This vibration produces and accelerates degenerative changes in vascular tissue by a process similar to the structural fatigue of metals by vibration. The author proposes that the turbulent blood flow within an aneurysm contributes to the degeneration of the elastica, and the production of the atheromatous changes, characteristically seen in its wall. This weakens the wall causing continuing enlargement and eventual rupture.

Intracranial aneurysms associated with unsuspected aortic coarctation

2002 ◽  
Vol 97 (5) ◽  
pp. 1221-1225 ◽  
Author(s):  
Rodrigo Mercado ◽  
Susana López ◽  
Carlos Cantú ◽  
Angel Sanchez ◽  
Rogelio Revuelta ◽  
...  
Keyword(s):  
Aortic Coarctation ◽  
Intracranial Aneurysms ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Young Patients ◽  
Clinical Information ◽  
Aneurysm Rupture ◽  
Adolescent And Young Adult ◽  
Imaging Data ◽  
Content Type ◽  
Fine Print

✓ Intracranial aneurysms (IAs) are found more often in patients with aortic coarctation (AC) than in the general population and aneurysm rupture occurs much earlier in the lives of these patients when there is coexistent AC. The diagnosis of AC is frequently made only after a serious cerebrovascular complication has developed. The aim of this paper is to call attention to AC in patients presenting with aneurysmal subarachnoid hemorrhage. The literature is reviewed, the key clinical features are highlighted, and the proposed pathogenesis of this association is discussed. The authors present clinical information and imaging data obtained in three young patients with ruptured IAs that were associated with initially unnoticed AC. Abnormal results of cardiovascular examinations led the authors to consider an underlying AC, which was later confirmed by aortography. These aneurysms were successfully treated prior to correction of the ACs. The diagnosis of AC should be considered in adolescent and young adult patients presenting with IAs.

Bioabsorbable polymeric material coils for embolization of intracranial aneurysms: a preliminary experimental study

2001 ◽  
Vol 94 (3) ◽  
pp. 454-463 ◽  
Author(s):  
Yuichi Murayama ◽  
Fernando Viñuela ◽  
Satoshi Tateshima ◽  
Joon K. Song ◽  
Nestor R. Gonzalez ◽  
...  
Keyword(s):  
Polymeric Material ◽  
Intracranial Aneurysms ◽  
Blood Clot ◽  
Fibrous Tissue ◽  
Clinical Manifestations ◽  
Embolic Agent ◽  
Parent Artery ◽  
Content Type ◽  
Fine Print

Object. A new embolic agent, bioabsorbable polymeric material (BPM), was incorporated into Guglielmi detachable coils (GDCs) to improve long-term anatomical results in the endovascular treatment of intracranial aneurysms. The authors investigated whether BPM-mounted GDCs (BPM/GDCs) accelerated the histopathological transformation of unorganized blood clot into fibrous connective tissue in experimental aneurysms created in swine. Methods. Twenty-four experimental aneurysms were created in 12 swine. In each animal, one aneurysm was embolized using BPM/GDCs and the other aneurysm was embolized using standard GDCs. Comparative angiographic and histopathological data were analyzed at 2 weeks and 3 months postembolization. At 14 days postembolization, angiograms revealed evidence of neck neointima in six of eight aneurysms treated with BPM/GDCs compared with zero of eight aneurysms treated with standard GDCs (p < 0.05). At 3 months postembolization, angiograms demonstrated that four of four aneurysms treated with BPM/GDC were smaller and had neck neointima compared with zero of four aneurysms treated with standard GDCs (p = 0.05). At 14 days, histological analysis of aneurysm healing favored BPM/GDC treatment (all p < 0.05): the grade of cellular reaction around the coils was 3 ± 0.9 (mean ± standard deviation) for aneurysms treated using BPM/GDCs compared with 1.6 ± 0.7 for aneurysms treated using GDCs alone; the percentage of unorganized thrombus was 16 ± 12% compared with 37 ± 15%, and the neck neointima thickness was 0.65 ±0.26 mm compared with 0.24 ±0.21 mm, respectively. At 3 months postembolization, only neck neointima thickness was significantly different (p < 0.05): 0.73 ± 0.37 mm in aneurysms filled with BPM/GDCs compared with 0.16 ± 0.14 mm in aneurysms filled with standard GDCs. Conclusions. In experimental aneurysms in swine, BPM/GDCs accelerated aneurysm fibrosis and intensified neck neointima formation without causing parent artery stenosis or thrombosis. The use of BPM/GDCs may improve long-term anatomical outcomes by decreasing aneurysm recanalization due to stronger in situ anchoring of coils by organized fibrous tissue. The retraction of this scar tissue may also decrease the size of aneurysms and clinical manifestations of mass effect observed in large or giant aneurysms.

Excimer laser—assisted bypass in aneurysm treatment: short-term outcomes

2002 ◽  
Vol 97 (5) ◽  
pp. 1029-1035 ◽  
Author(s):  
Eva H. Brilstra ◽  
Gabriel J. E. Rinkel ◽  
Catharina J. M. Klijn ◽  
Albert van der Zwan ◽  
Ale Algra ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Clinical Condition ◽  
Intracranial Aneurysms ◽  
High Flow ◽  
Parent Artery ◽  
Content Type ◽  
Poor Outcome ◽  
Risk Of Rupture ◽  
Clip Application ◽  
Fine Print

Object. If clip application or coil placement for treatment of intracranial aneurysms is not feasible, the parent vessel can be occluded to induce thrombosis of the aneurysm. The Excimer laser—assisted anastomosis technique allows the construction of a high-flow bypass in patients who cannot tolerate such an occlusion. The authors assessed the complications of this procedure and clinical outcomes after the construction of high-flow bypasses in patients with intracranial aneurysms. Methods. Data were retrospectively collected on patient and aneurysm characteristics, procedural complications, and functional outcomes in 77 patients in whom a high-flow bypass was constructed. Logistic regression analysis was used to quantify the relationships between patient and aneurysm characteristics on the one hand and outcome measures on the other. Fifty-one patients harbored a giant aneurysm, 24 patients suffered from a ruptured aneurysm, and 35 patients from an unruptured symptomatic aneurysm. In 22 patients (29%; 95% confidence interval [CI] 19–40%) a permanent deficit developed from an operative complication. At a median follow-up period of 2.5 months, 25 patients (32%; 95% CI 22–44%) were dependent or had died; in 10 of these patients (13% of all patients; 95% CI 6–23%) operative complications were the single cause of this poor outcome. Univariate analysis demonstrated that a poor clinical condition before treatment (odds ratio [OR] 4.7; 95% CI 1.7–13.3) and a history of cardiovascular disease (OR 4.1; 95% CI 1–16.2) increased the risk of poor outcome. Multivariate analysis demonstrated that only the clinical condition before treatment was significantly related to outcome (OR 4; 95% CI 1.3–11.9). Conclusions. In patients with an intracranial aneurysm that cannot be treated by clip application or coil placement, and in whom occlusion of the parent artery cannot be tolerated, the construction of a high-flow bypass should be considered. This procedure carries a considerable risk of complications, but this should be weighed against the disabling or life-threatening effects of compression, the high risk of rupture, and the substantial chance of poor outcome after the rupture of such aneurysms.

Risk factors for the formation of multiple intracranial aneurysms

2001 ◽  
Vol 94 (5) ◽  
pp. 728-732 ◽  
Author(s):  
Habib E. Ellamushi ◽  
Joan P. Grieve ◽  
H. Rolf Jäger ◽  
Neil D. Kitchen
Keyword(s):  
Risk Factors ◽  
Family History ◽  
Cigarette Smoking ◽  
Cerebrovascular Disease ◽  
Intracranial Aneurysms ◽  
Content Type ◽  
Multiple Aneurysms ◽  
Female Patients ◽  
History Of ◽  
Fine Print

Object. Several factors are known to increase the risk of subarachnoid hemorrhage (SAH) and spontaneous intracerebral hematoma. However, information on the roles of these same factors in the formation of multiple aneurysms is less well defined. The purpose of this study was to examine factors associated with an increased risk of multiple aneurysm formation. Methods. A retrospective review of the medical records of all patients with a diagnosis of SAH and intracranial aneurysms who were admitted to a single institution between 1985 and 1997 was undertaken. The authors examined associations between risk factors (patient age and sex, menopausal state of female patients, hypertension, cigarette smoking, alcohol consumption, history of cardiovascular disease or diabetes mellitus, and family history of cerebrovascular disease) and the presence of multiple aneurysms by using the Fisher exact test and logistic regression analysis. Of 400 patients admitted with a diagnosis of cerebral aneurysms, 392 were included in the study (287 women and 105 men). Two hundred eighty-four patients harbored a single aneurysm and 108 harbored multiple aneurysms (2 aneurysms in 68 patients, three aneurysms in 22 patients, four aneurysms in 13 patients, and five aneurysms in five patients). Conclusions. Statistical analysis revealed that, as opposed to the occurrence of a single aneurysm, there was a significant association between the presence of multiple aneurysms and hypertension (p < 0.001), cigarette smoking (p < 0.001), family history of cerebrovascular disease (p < 0.001), female sex (p < 0.001), and postmenopausal state in female patients (p < 0.001).

Preliminary report of a hollow-centered balloon for intravascular occlusion of intracranial aneurysms or arteriovenous fistulas

1980 ◽  
Vol 53 (2) ◽  
pp. 262-265 ◽  
Author(s):  
Milton D. Heifetz ◽  
Grant B. Hieshima ◽  
C. Mark Mehringer
Keyword(s):  
Arteriovenous Fistula ◽  
Preliminary Report ◽  
Intracranial Aneurysms ◽  
Giant Aneurysm ◽  
Parent Artery ◽  
Content Type ◽  
Arteriovenous Fistulas ◽  
Preliminary Study ◽  
Intravascular Occlusion ◽  
Fine Print

✓ A doughnut-shaped balloon has been designed that can be inserted intravascularly by catheter to occlude the orifice of an intracranial berry or giant aneurysm or arteriovenous fistula. The blood in the parent artery can continue to flow uninterrupted through the hole in the balloon. In a preliminary study, an arteriovenous fistula was successfully obliterated in a dog. The technique for placing the balloon is described.

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