Incomplete Circle Research Articles

Can acetabular dysplasia be measured on axial CT? A measurement for trauma surgeons

BackgroundAcetabular dysplasia has been theorized as a risk factor instability amongst common acetabular fractures, such as posterior wall (PW) fractures. However, common radiographic measurements often cannot be acquired in trauma patients. We evaluated axial computed tomography (CT) scans to identify novel, easily-obtained measurements that correlate with acetabular dysplasia for use in surgical indications and planning. MethodsPatients with known acetabular dysplasia undergoing elective periacetabular osteotomy were selected. A different group of patients without pelvic ring or acetabular fractures from an institutional trauma registry were selected as a comparison group. Standard indices of dysplasia were collected, such as center-edge angle (CEA). Acetabular geometric measurements were taken at three axial levels: 0 – cranial CT slice at the dome; 1 – cranial CT where the dome is an incomplete circle; 2 – cranial CT with femoral head visible. Distances between levels were also calculated: Levels 0–1 (Dome Height; DH), Levels 1–2 (Head Height; HH), and Dome-Head Difference (DH – HH = DHD). ResultsDH, HH, and DHD were all significantly correlated with CEA, Tonnis angle, and Sharp's angle in dysplastic hips. All dysplastic hips had DH ≤ 2.5 mm and HH ≥ 1.25 mm. DHD ≤ 0 mm was most specific (93.6 % sensitive, 77.3 % specific) for predicting dysplasia. ConclusionDH ≤ 2.5 mm, HH ≥ 1.25 mm, and DHD ≤ 0 mm were independently associated with dysplasia on axial CT scans. These measurements may be quickly and easily used by trauma surgeons to assess a trauma-based axial CT scan for acetabular dysplasia.

Study on the Correlation Between Cerebral Vascular Variation and Hypertension

Abstract OBJECTIVE To investigate the association between cerebral vascular variation and hypertension in adults. METHODS Using a cross-sectional study, the current and retired employees of Kailuan Group who participated in the physical examination of Kailuan General Hospital and underwent magnetic resonance examination in 2020–2022 were taken as the observation objects, and a total of 1,029 people finally met the inclusion and exclusion criteria. The observation objects were divided into 4 groups: no cerebral vascular variation, only vertebral artery hypoplasia (VAH), only incomplete posterior Circle of Willis (ipCoW), and combined variations (VAH + ipCoW). Binary logistic regression models were used to explore the effects of different types of cerebral vascular variation on hypertension. RESULTS The mean age of the study population was 55.2 ± 11.4 years. The percentages in no cerebral vascular variations, VAH only, ipCoW only, and combined variations groups were 21.1%, 11.5%, 46.8%, and 20.6%, respectively. Using hypertension as the dependent variable and cerebral vascular variation type as the independent variable, and adjusting for multiple confounders, the results showed that the presence of both VAH and ipCoW was positively associated with hypertension risk (OR = 2.410, 95% CI = 1.401–4.146). Stratified analysis showed that the association was more pronounced in people younger than 55 (OR = 4.437, 95% CI = 1.891–10.406), whereas no significant association was found in people older than 55 (P > 0.05). CONCLUSIONS There is a positive correlation between cerebral vascular variation and hypertension, and this association is predominantly observed in the younger population.

Incomplete circle of Willis as a risk factor for intraoperative ischemic events during carotid endarterectomies performed under regional anesthesia - A prospective case-series.

The role of the willisian collaterals during carotid endarterectomies (CEAs) is a debated issue. The aim of the present work was to test whether an incomplete or non-functional circle of Willis (CoW) is a risk factor for ischemic events during CEA. CEAs were performed under local anesthesia. Patients were considered symptomatic (SY) if neurological signs appeared after the cross-clamping phase. In SY patients shunt insertion was performed. CoW on CT angiograms (CTa) were analyzed offline and categorized as non-functional (missing or hypoplastic collaterals) or functional collaterals by three neuroradiologists. Near-infrared spectroscopy (NIRS) was performed throughout the procedure. Based on CTa, 67 incomplete circles were found, 54 were asymptomatic (ASY) and 13 were SY. No complete CoW was found among the SY patients. Significant differences could be detected between incomplete and complete circles between ASY and SY groups (Chi-square: 6.08; p = 0.013). The anterior communicating artery was missing or hypoplastic in 5/13 SY cases. There were no cases of the non-functional anterior communicating arteries in the ASY group (Chi-square: 32.9; p = 10-8). A missing or non-functional bilateral posterior communicating artery was observed in 9/13 SY and in 9/81 ASY patients (Chi-square: 24.4; p = 10-7). NIRS had a sensitivity of 76.9% and a specificity of 74.5% in detecting neurological symptoms. Collateral ability of the CoW may be a risk factor for ischemic events during CEAs. Further studies should delineate whether the preoperative assessment of collateral capacity may be useful in decision-making about shunt use during CEA.

The incomplete circle of Willis is associated with vulnerable intracranial plaque features and acute ischemic stroke

BackgroundThe circle of Willis (CoW) plays a significant role in intracranial atherosclerosis (ICAS). This study investigated the relationship between different types of CoW, atherosclerosis plaque features, and acute ischemic stroke (AIS). MethodsWe investigated 97 participants with AIS or transient ischemic attacks (TIA) underwent pre- and post-contrast 3T vessel wall cardiovascular magnetic resonance within 7 days of the onset of symptoms. The culprit plaque characteristics (including enhancement grade, enhancement ratio, high signal in T1, irregularity of plaque surface, and normalized wall index), and vessel remodeling (including arterial remodeling ratio and positive remodeling) for lesions were evaluated. The anatomic structures of the anterior and the posterior sections of the CoW (A-CoW and P-CoW) were also evaluated. The plaque features were compared among them. The plaque features were also compared between AIS and TIA patients. Finally, univariate and multivariate regression analysis was performed to evaluate the independent risk factors for AIS. ResultPatients with incomplete A-CoW showed a higher plaque enhancement ratio (P = 0.002), enhancement grade (P = 0.01), and normalized wall index (NWI) (P = 0.018) compared with the patients with complete A-CoW. A higher proportion of patients with incomplete symptomatic P-CoW demonstrated more culprit plaques with high T1 signals (HT1S) compared with those with complete P-CoW (P = 0.013). Incomplete A-CoW was associated with a higher enhancement grade of the culprit plaques [odds ratio (OR):3.84; 95% CI: 1.36–10.88, P = 0.011], after adjusting for clinical risk factors such as age, sex, smoking, hypertension, hyperlipemia, and diabetes mellitus. Incomplete symptomatic P-CoW was associated with a higher probability of HT1S (OR:3.88; 95% CI: 1.12–13.47, P = 0.033), after adjusting for clinical risk factors such as age, sex, smoking, hypertension, hyperlipemia, and diabetes mellitus. Furthermore, an irregularity of the plaque surface (OR: 6.24; 95% CI: 2.25–17.37, P < 0.001), and incomplete symptomatic P-CoW (OR: 8.03, 95% CI: 2.43–26.55, P = 0.001) were independently associated with AIS. ConclusionsThis study demonstrated that incomplete A-CoW was associated with enhancement grade of the culprit plaque, and incomplete symptomatic side P-CoW was associated with the presence of HT1S of culprit plaque. Furthermore, an irregularity of plaque surface and incomplete symptomatic side P-CoW were associated with AIS.

АРИЯ ИЗАБЕЛЛЫ И ПОСЛЕДНЕЕ СЛОВО ХРИСТА: ИНТЕРМЕДИАЛЬНАЯ ИНТЕРТЕКСТУАЛЬНОСТЬ В ПОРТРЕТАХ СЫНА ИОГАННА КУПЕЦКОГО

The article is in analysis of the visual, musical and textual aspects of the relevant scientific issue – the concept of intermedial intertextuality – on the example of two engravings created in mezzotint technique based on the selfportrait of the outstanding Baroque portraitist of Bohemian origin Johannes Kupetsky with his son Christoph, and on Christoph’s posthumous portrait. The first one was created by the Nuremberg engraver Bernhard Vogel, the second – by him or by his apprentice Valentin Daniel Preissler. In addition to the images, those prints contain poetic inscriptions, quotations and musical texts. In a lifetime portrait the musical text was identified as the incipit of an aria of the Baroque opera by Reinhard Kaiser. Thanks to it, the quote from Statius’s “Thebaid” in the engraving was associated with the experience of marital adultery. In the posthumous portrait of Christoph, accepting from Manus Dei a scroll with the emblem of “Τετέλεσται”, the motto bears the evangelical connotations – the execution of the sentence and the completion of the earthly path. The image of the siren on the emblem corresponds to the image of the personification of Eternity in the Iconology by Cesare Ripa. However, the siren in the Nuremberg mezzotint holds not a ball but a compass, outlining an incomplete circle – a motif associated with the personification of Perfection. The emblem on the mezzotint illustrates a syncretic image of Perfection found in Eternity

From surgical clamping to endovascular flow arrest/reversal: the concept behind the system.

Carotid artery lesions are frequently composed of friable, thrombotic, ulcerated and/or hemorrhagic materials which can embolize during surgical or endovascular interventions. The use of embolic protection devices (EPD) during carotid angioplasty and stenting (CAS) has been proven to be associated with a reduction of the embolic load. Many studies indicate that the clinical results of CAS are comparable with the best surgical series, when EPD are routinely applied. The proximal EPD work by interrupting or reversing the blood flow in the common carotid artery/internal carotid artery (CCA/ICA). Once established the endovascular flow arrest/reversal, these systems have the advantages of promoting a protected crossing of the lesion and blocking both macro-emboli and micro-emboli. Moreover, proximal neuroprotection implies no manipulation of the device in the distal ICA, neither during device deployment nor during device retrieval, and reduces the risk of arterial spasm, dissection, or intimal damage. The choice between transfemoral and transcervical proximal EPD should account for different factors: local availability, operator expertise, and patient characteristics including anatomical features precluding flow arrest/reversal (e.g., incomplete circle of Willis), femoral access (e.g., unfavorable aortic arch anatomy), or transcervical access (e.g., diseased CCA).

Computational study of fenestration and parallel grafts used in TEVAR of aortic arch aneurysms.

To explore the differences between fenestration technique and parallel grafts technique of thoracic endovascular aortic repair, and evaluate the risk of complications after interventional treatment of aortic arch aneurysms. A three-dimensional aortic model was established from the follow-up imaging data of patient who reconstructed the superior arch vessel by the chimney technique, which was called the chimney model. Based on the chimney model, the geometric of the reconstructed vessel was modified by virtual surgery, and the normal model, fenestration model and periscope model were established. The blood flow waveforms measured by 2D phase contrast magnetic resonance imaging were processed as the boundary conditions of the ascending aorta inlet and the superior arch vessels outlets of the normal model. The pressure waveform of descending aorta was obtained using three-element Windkessel model, and specific pressure boundary conditions were imposed at reconstructed branches for the postoperative models. Through computational fluid dynamics simulations, the hemodynamic parameters of each model were obtained. The reconstructed vessel flow rate of the periscope model and the fenestration model are 33% and 50% of that of the normal model, respectively. The pressure difference between the inner and outer walls of the fenestration stent and periscope stent is 3.15 times and 7.56 times that of the chimney stent. The velocity in the fenestration stent and periscope stent is uneven. The high relative residence time is concentrated in the region around the branch stents, which is prone to thrombosis. The "gutter" part of the chimney model may become larger due to the effect of the stent-graft DF, increasing the risk of endoleak. For patients with incomplete circle of Willis, the periscope technique to reconstruct the supra-arch vessels may affect blood perfusion. It is recommended to use balloon-expandable stent for fenestration stent and periscope stent, and self-expanding stent for chimney stent. For patients with aortic arch aneurysms, the fenestration technique may be superior to the parallel grafts technique.

Evaluation of Circle of Willis variants using magnetic resonance angiography

The Circle of Willis (COW) is an important collateral pathway to protect the persistence of cerebral blood perfusion. This study aims to investigate the morphological variants of this significant vascular structure with a large study population. 867 patients who had undergone MR angiography (MRA) evaluation were enrolled in this study. The MRA images of these patients obtained by the three-dimensional time-of-flight technique were re-interpreted to measure the vessel diameters of all components of the COW and classify the COW variations. In addition, correlations of the vessel calibers and the integrity of the COW with gender and age groups were presented. There was female dominance in the study population, and the mean age was 48. Type A was the most common variation in anterior (75.78%) and posterior (53.98%) circulation. Types G and H were the other common variation in the anterior circulation, and types E and D were the second and third common variations in the posterior COW, respectively. Smaller calibration for both ICAs, both P1s and BA were observed in females compared with the male group. Diameters of the BA, and both P1 segments were lower, and the left PCom diameter was significantly higher in the patients with a complete circle. There was a significant sex and age difference regarding the distribution of the complete, partially complete, and incomplete circle groups. The significant differences in the vessel calibers of specific components of the COW for complete, partial, and incomplete circulations revealed by this study should be explained with further research. In addition, meta-analyses with other studies in the literature might be a guide to understanding the morphological alterations of the COW and their relationships with a complete and non-complete circle.

Incomplete circle of Willis variants and stroke outcome

BackgroundThere is considerable variation in circle of Willis morphology among the general population, and these variations have been correlated with risk of aneurysms, cerebral ischemia, and other clinical events. PurposeTo investigate the relationship between circle of Willis variants and stroke outcome. Materials and methodsWe performed a retrospective study involving 297 patients from our institution’s acute stroke academic registry. All received MRA examinations of the head upon admission for acute strokes. All imaging was reviewed to assess for circle of Willis variants (particularly A1 and P1 aplasia or hypoplasia) along with vertebral artery aplasia or hypoplasia. Stroke outcome was defined as good (walking independently at the time of discharge) or poor (inability to walk at discharge, assistance needed to walk at discharge, or death). Severity of stroke was assessed using the National Institute of Health Stroke Scale. ResultsAn incomplete circle of Willis was seen in 34% of subjects. There was no significant association between age, gender, hypertension, or presence of arterial stenosis and circle of Willis completeness. Using logistic regression, we found that the presence of an incomplete circle of Willis decreased the odds of a stroke patient having a good outcome by 47% (p = 0.046, OR 0.53, 95% CI 0.281–0.988), after adjusting for age and severity of stroke at admission. ConclusionThis study suggests that an incomplete circle of Willis may be associated with a poorer prognosis for stroke patients.

Association of incomplete Circle of Willis with severity of acute ischaemic stroke

Background: The extent of damage by ischaemic stroke and the course of illness depend largely on the presence of collateral vessels around the affected area. The Circle of Willis (CoW), which serves as an important potential collateral pathway in maintaining adequate blood flow around the brain, is known to have variable patency. So the completeness of CoW is expected to influence the severity of ischaemic stroke. Objective: The objective of the study was to determine the association of completeness of Circle of Willis with severity of acute ischaemic stroke. Methods: It was a cross-sectional study done in Bangabandhu Sheikh Mujib Medical University, Dhaka from March, 2015 to August, 2017. A total of 42 patients of acute ischaemic stroke who were undergoing Digital Subtraction Angiography (DSA) for different reasons were selected by purposive sampling method. Data regarding completeness of Circle of Willis were obtained from DSA. National Institutes of Health Stroke Scale (NIHSS) score were measured to assess the severity of stroke. Then the severities of stroke between the complete and incomplete Circle of Willis groups were compared. Results: A total of 27 male and 15 female patients were enrolled. Among them, 47.6% (20) had complete CoW and it was incomplete in rest 52.4% (22). Median (range) of NIHSS scores of complete and incomplete CoW group was 4.5 (0-17) and 9.5 (3-21) respectively. Mean NIHSS (±SD) for the complete and incomplete CoW was 6.60 (±4.97) and 9.95 (±5.10) respectively. The difference of mean between the two groups was found to be statistically significant (p=0.037). Odd’s Ratio (OR) for development of more severe stroke in patients with incomplete CoW was 4.5, 95% Confidence Interval (CI) 1.18-18.13 which was statistically significant (p=0.029). Conclusion: It was concluded that incomplete Circle of Willis is associated with more severe stroke in acute ischaemic stroke patients. Bangladesh Med Res Counc Bull 2021; 47(2): 181-191

Age-related changes in the completeness of the circle of Willis in children.

The circle of Willis is a circulatory anastomosis that supplies blood to the brain. If any of the bridging segments arehypoplastic or absent, the capacity for collateral flow in the setting of large vessel occlusion may be decreased. Outside of the neonatal period, the prevalence of a complete circle of Willis (CoW) in the pediatric population has not been well described. Our objectives include determining the prevalence of a complete CoW in children and identifying if there is an age-related "loss" of arterial segments. Following IRB approval, angiograms of the CoW performed on a 3-T MR platform from 2016 to 2020 on patients 21years or younger were retrospectively reviewed. Any patient with underlying arterial pathology that may affect the CoW was excluded. Patient age and gender at the time of imaging were obtained. In total, 592 pediatric CoW were assessed. Frequencies of completeness were calculated in two different fashions: scenario 1 where a CoW was characterized as complete even if it contained hypoplastic vessels (88.8%), and scenario 2 where it was characterized as complete after excluding hypoplastic vessels (44.0%). In both scenarios, our data showed that older age was more associated with an incomplete CoW (p < 0.0001). In addition, we found a higher percentage of males with an incomplete CoW compared with females (p < 0.0001). The presence of a complete CoW is greater in our pediatric population than what has been reported in adults. The prevalence of an incomplete circle of Willis also increases significantly with age.

Total arch replacement with the frozen elephant trunk technique for a right-sided aortic arch with a Kommerell diverticulum and aberrant right vertebral artery

The best treatment for a right-sided aortic arch (RAA) and Kommerell diverticulum (KD) has not been determined due to the rarity of these conditions. The current trend in the treatment of this disease is to increase the endovascular approach without a sternotomy. We describe a rare condition with an association of an RAA with a KD of an aberrant left subclavian artery and an anomalous right vertebral artery originating from the aortic arch (AVA). The left vertebral artery was missing. Also, there was an incomplete circle of Willis due to the absence of the left and right posterior communication arteries. Therefore, the AVA was the only artery to supply the vertebral-basilar system. In our case, a simple thoracic endovascular aortic repair was not suitable because of the sharply curved arch and short landing zone. Also, a debranching thoracic endovascular aortic repair was not appropriate because that approach would not permit reconstruction of the AVA. The patient successfully underwent a total arch replacement with the frozen elephant trunk technique. This procedure could be an effective option for patients with RAAs with KDs associated with another arch vessel anomaly.

Cerebrovascular Variants and the Role of the Selfish Brain in Young-Onset Hypertension.

Background:Variants in the posterior anatomy of the cerebral circulation are associated with hypertension and lower cerebral blood flow in midlife (age ≈55 years); however, whether these variants are a result of aging or long-term exposure to high blood pressure is unclear. Additionally, the role these variants play in early onset of hypertension (<40 years) and poor cerebral perfusion in this population is unknown.Methods:We retrospectively examined whether specific cerebrovascular variants (vertebral artery hypoplasia and absent/hypoplastic posterior communicating arteries (an incomplete posterior circle of Willis) measured via magnetic resonance angiography) were associated with a diagnosis of hypertension in 220 young adults (<40 years; n=164 primary hypertensive [mean age±SD, 32±6 years] and n=56 [30±6 years] normotensive adults). Whether cerebrovascular variants were associated with lower cerebral blood flow (phase-contrast angiography) was measured in the hypertensive group only (n=146).Results:Binary logistic regression (adjusted for age, sex, and body mass index) showed that vertebral artery hypoplasia with an incomplete posterior circle of Willis was associated with hypertension diagnosis (P<0.001, odds ratio; 11.79 [95% CI, 3.34–41.58]). Vertebral artery hypoplasia plus an incomplete circle of Willis was associated with lower cerebral blood flow in young adults with hypertension (P=0.0172).Conclusions:Vertebral artery hypoplasia plus an incomplete posterior circle of Willis independently predicts hypertension in young adults suggesting that this variant is not acquired with aging into midlife. Importantly this variant combination was associated with lower cerebral perfusion, which may have long-term consequences on cerebrovascular health in young adults with hypertension.

Cerebral Infarction During Cervical Veno-Arterial Extracorporeal Membrane Oxygenation in Children: Can it be Predicted?

Veno-arterial extra-corporeal membrane oxygenation (VA ECMO) in children is often established by cannulation of the right carotid artery and the right internal jugular vein. Cerebral infarction which is sometimes seen in such cases may be secondary to an incomplete circle of Willis. We present 3 cases with VA ECMO using cervical cannulation who suffered cerebral infarction which may be attributed to an incomplete circle of Willis.

Different anatomical variations of circle of Willis in adult patients on magnetic resonance angiography

Background: The COW shows vast variations in different individuals. The aim of this study was to evaluate and describe the prevalence and patterns of arterial variants and the different morphological variations of the COW on MRA in adult Pakistanis. Aim: To find the different anatomical variations of Circle of Willis in adult patients on magnetic resonance angiography. Methodology: In this descriptive study a total of 90 patients with ages 20-90 years, were selected for the study between July 2021 till October 2021. The adult patients were referred for screening MRA brain in the Department of Radiology. The protocol selected to visualize the COW was 3D-TOF MRA. Results: Data analysis demonstrates that out of total 90 patients, 51(56.7%) were males and 39(43.3%) were females. Overall, 66(79.5%) circles were complete in anatomical configuration and 24(20.5) were incomplete. The anterior circle was complete in 73(81.1%) subjects and incomplete in 17(18.9%) subjects. The posterior circle was complete in 83(92.2%) subjects and incomplete in 7(7.8%) subjects.The most common variation of COW was hypoplasia/absence of segments of Circle of Willis. ACA was the most frequent segment of Circle of Willis that was hypoplastic/absent followed by A1 segment of right ACA is absent in 6(7.2%) subjects and A1segment of right ACA is hypoplastic in 6(7.2%) subjects. Conclusion: The study concludes that mostly the COW is complete in Pakistani adults. There are variations particularly in anterior part as compared to the posterior part of the COW. The most common variants are of A1 segment of Right ACA as compared to other type of variants. Keywords: Circle of Willis, 3D-TOF-MRA, Anterior circulation, Posterior circulation, Complete circle, Incomplete circle,

National Institutes of Health stroke scale score at admission can predict functional outcomes in patients with ischemic stroke undergoing carotid endarterectomy

ObjectiveThe aim of present study was to evaluate the prognostic effect of the National Institutes of Health stroke scale (NIHSS) score for patients who had undergone acute carotid endarterectomy (CEA) and assess the clinical and morphologic factors that could predict for worse outcomes. MethodsThe data from 183 consecutive patients who had undergone CEA after ischemic stroke were analyzed from January 2015 to January 2021. The patients were divided into two groups using the NIHSS score cutoff of 4. Functional dependence was assessed at hospital discharge and 90 days after discharge. ResultsOf the 183 patients, 102 (55.7%) had had a minor stroke (group A; NIHSS score of ≤4) and 81 (44.3%) had had a moderate to major stroke (group B; NIHSS score >4). Groups A and B showed significant differences in their intracranial anatomic features, including the presence of an incomplete circle of Willis (7.8% vs 17.3%; P = .05), cerebral ischemic lesion volume ≥4000 mm3 (5.9% vs 24.7%; P ≤ .001), and a high Alberta stroke program early computed tomography score of 8 to 10 (75.5% vs 44.4%; P ≤ .001). The overall rate of combined perioperative stroke, myocardial infarction, and death was 1.1%, with no strokes recorded during the interval to CEA. Patients in group A had a lower rate of functional dependence at discharge (4.9% vs 35.8%; P ≤ .001) and at 90 days after the index stroke event (2.5% vs 19.6%; P ≤ .001) compared with those in group B. Using multivariate binary logistic regression, an admission NIHSS score >4 was significantly associated with higher odds of functional dependence at discharge (odds ratio, 7.9; 95% confidence interval, 2.7-18.5; P ≤ .001) and at 90 days (odds ratio, 10.4; 95% confidence interval, 2.7-19.3; P = .002). ConclusionsAn NIHSS score >4 at admission increased the risk of a higher modified Rankin scale score at both hospital discharge and 90 days after the index stroke event. Acute CEA was safe and feasible for patients with ischemic stroke, even if they had previously undergone intravenous thrombolysis.

Circle of Willis variants and their association with outcome in patients with middle cerebral artery-M1-occlusion stroke.

BackgroundAn incomplete circle of Willis (CoW) has been associated with a higher risk of stroke and might affect collateral flow in large vessel occlusion (LVO) stroke. We aimed to investigate the distribution of CoW variants in a LVO stroke and transient ischemic attack (TIA) cohort and analyze their impact on 3‐month functional outcome.MethodsCoW anatomy was assessed with time‐of‐flight magnetic resonance angiography (TOF‐MRA) in 193 stroke patients with acute middle cerebral artery (MCA)‐M1‐occlusion receiving endovascular treatment (EVT) and 73 TIA patients without LVO. The main CoW variants were categorized into four vascular models of presumed collateral flow via the CoW.Results82.4% (n = 159) of stroke and 72.6% (n = 53) of TIA patients had an incomplete CoW. Most variants affected the posterior circulation (stroke: 77.2%, n = 149; TIA: 58.9%, n = 43; p = 0.004). Initial stroke severity defined by the National Institutes of Health Stroke Scale (NIHSS) on admission was similar for patients with and without CoW variants. CoW integrity did not differ between groups with favorable (modified Rankin Scale [mRS]): 0–2) and unfavorable (mRS: 3–6) 3‐month outcome. However, we found trends towards a higher mortality in patients with any type of CoW variant (p = 0.08) and a higher frequency of incomplete CoW among patients dying within 3 months after stroke onset (p = 0.119). In a logistic regression analysis adjusted for the potential confounders age, sex and atrial fibrillation, neither the vascular models nor anterior or posterior variants were independently associated with outcome.ConclusionOur data provide no evidence for an association of CoW variants with clinical outcome in LVO stroke patients receiving EVT.

Plaque Wall Distribution Pattern of the Atherosclerotic Middle Cerebral Artery Associates With the Circle of Willis Completeness.

Objective: Investigating the relevance of the incomplete circle of Willis (COW) to the plaque wall distribution in the atherosclerotic middle cerebral arteries (MCAs) through utilizing high-resolution magnetic resonance imaging (HR-MRI), and its potential clinical impact.Methods: This hospital-based study enrolled consecutive adult patients with acute ischemic stroke or transient ischemic attack, who received a 3.0T Achieva MR system scanning. The COW completeness was evaluated on MR angiography imaging, including anterior (A) and posterior (P)-COW sections. The MCA plaque wall distribution was assessed on HR-MRI. The occurrence of perforator infarction was detected on diffusion-weighted imaging.Results: Among 87 patients (mean age = 62.39 ± 11.64 years old) with atherosclerotic plaques in the MCA M1 segments, the incomplete COW types were more prevalent than the complete COW type (incomplete P-COW, 83.9%; incomplete A-COW, 36.8%; complete COW, 8.1%). The incomplete A-COW had more inferior but fewer ventral plaques of MCA atherosclerosis than the complete A-COW, while the incomplete P-COW had fewer inferior MCA plaques than the complete P-COW. Moreover, symptomatic MCA plaques causing perforator infarctions were more likely to locate on the superior wall.Conclusion: Our findings suggested that the COW completeness could influence the vessel wall distribution of the MCA plaques, among which the superior plaques of symptomatic MCA atherosclerosis was associated with branch occlusive disease.

An incomplete Circle of Willis is not a risk factor for white matter hyperintensities: The Tromsø Study

ObjectiveThe Circle of Willis (CoW) is often underdeveloped or incomplete, leading to suboptimal blood supply to the brain. As hypoperfusion is thought to play a role in the aetiology of white matter hyperintensities (WMH), the objective of this study was to assess whether incomplete CoW variants were associated with increased WMH volumes compared to the complete CoW. MethodsIn a cross-sectional population sample of 1751 people (age 40–84 years, 46.4% men), we used an automated method to segment WMH using T1-weighted and T2-weighted fluid-attenuated inversion recovery image obtained at 3T. CoW variants were classified from time-of-flight scans, also at 3T. WMH risk factors, including age, sex, smoking and blood pressure, were obtained from questionnaires and clinical examinations. We used linear regression to examine whether people with incomplete CoW variants had greater volumes of deep WMH (DWMH) and periventricular WMH (PWMH) compared to people with the complete CoW, correcting for WMH risk factors. ResultsParticipants with incomplete CoW variants did not have significantly higher DWMH or PWMH volumes than those with complete CoW when accounting for risk factors. Age, pack-years smoking, and systolic blood pressure were risk factors for increased DWMH and PWMH volume. Diabetes was a unique risk factor for increased PWMH volume. ConclusionIncomplete CoW variants do not appear to be risk factors for WMH in the general population.

Management of carotid stenosis for primary and secondary prevention of stroke: state-of-the-art 2020: a critical review.

Carotid atherosclerotic plaque is encountered frequently in patients at high cardiovascular risk, especially in the elderly. When plaque reaches 50% of carotid lumen, it induces haemodynamically significant carotid stenosis, for which management is currently at a turning point. Improved control of blood pressure, smoking ban campaigns, and the widespread use of statins have reduced the risk of cerebral infarction to <1% per year. However, about 15% of strokes are still secondary to a carotid stenosis, which can potentially be detected by effective imaging techniques. For symptomatic carotid stenosis, current ESC guidelines put a threshold of 70% for formal indication for revascularization. A revascularization should be discussed for symptomatic stenosis over 50% and for asymptomatic carotid stenosis over 60%. This evaluation should be performed by ultrasound as a first-line examination. As a complement, computed tomography angiography (CTA) and/or magnetic resonance angiography are recommended for evaluating the extent and severity of extracranial carotid stenosis. In perspective, new high-risk markers are currently being developed using markers of plaque neovascularization, plaque inflammation, or plaque tissue stiffness. Medical management of patient with carotid stenosis is always warranted and applied to any patient with atheromatous lesions. Best medical therapy is based on cardiovascular risk factors correction, including lifestyle intervention and a pharmacological treatment. It is based on the tri-therapy strategy with antiplatelet, statins, and ACE inhibitors. The indications for carotid endarterectomy (CEA) and carotid artery stenting (CAS) are similar: for symptomatic patients (recent stroke or transient ischaemic attack ) if stenosis >50%; for asymptomatic patients: tight stenosis (>60%) and a perceived high long-term risk of stroke (determined mainly by imaging criteria). Choice of procedure may be influenced by anatomy (high stenosis, difficult CAS or CEA access, incomplete circle of Willis), prior illness or treatment (radiotherapy, other neck surgery), or patient risk (unable to lie flat, poor AHA assessment). In conclusion, neither systematic nor abandoned, the place of carotid revascularization must necessarily be limited to the plaques at highest risk, leaving a large place for optimized medical treatment as first line management. An evaluation of the value of performing endarterectomy on plaques considered to be at high risk is currently underway in the ACTRIS and CREST 2 studies. These studies, along with the next result of ACST-2 trial, will provide us a more precise strategy in case of carotid stenosis.