Arterial Circulation Research Articles

Асимметрия мозгового кровообращения в бассейне внутренних сонных артерий у студентов при кратковременной умственной нагрузке: связь с эффективностью контроля поведения

The purpose of this paper was to study the relationship between cerebral circulation during shortterm mental load and the efficiency of behaviour control. Previous studies failed to provide a clear picture of the functional restructuring of cerebral circulation in response to mental activity. One of the reasons for the ambiguity of their results may be individual differences. This is confirmed by the existing typological differences in cerebral circulation at rest and in response to mental load. In this study, we highlighted another potential typological feature, namely, bilateral asymmetry of cerebral circulation in the internal carotid arteries. The available data suggest that the asymmetry of cerebral circulation is linked with the productivity of mental activity and the efficiency of behaviour control. Materials and methods. Rheoencephalography was used to study the parameters of cerebral circulation in 20 students (aged 19–23 years) during mental load (Go/No-Go test). The stimuli were presented on a monitor using the PsychoPy program. The reaction time and the number of errors were evaluated. Rheoencephalograms were recorded using the Reo-Spektr rheoencephalograph. Pulse volume at rest and during mental load in the internal carotid arteries was assessed according to the amplitude-frequency index (AFI). Blood flow asymmetry in the frontal regions was assessed using the asymmetry coefficient. Results. Under short-term mental load in students, a tendency towards a moderate increase in pulse volume in the frontal regions was observed. A negative correlation was established between the AFI in the right frontal region and the number of errors in the Go/No-Go test. The research into the relationship between blood flow asymmetry in the internal carotid arteries and execution accuracy of the Go/No-Go test revealed a positive correlation between the predominance of blood circulation in the left frontal area and test execution accuracy. Prospects for using the asymmetry of cerebral circulation in the internal carotid arteries to predict mental activity efficiency are discussed.

O015 CD34+ vascular stem cells play a key role in vein graft remodelling

Abstract Introduction Venous conduits that are grafted into arterial circulation undergo neointima remodelling, causing excessive hyperplasia that contributes to early graft failure which a major drawback of surgical vein grafting. Stem cells expressing the CD34 surface protein have been postulated to have a key role in the process, but their involvement has not been studied. Methods A segment of the inferior vena cava of wild-type mice was interposition grafted into mice in which CD34-expressing cells were located through their genetically induced expression of tdTomato red marker protein (CD34-CreERT2xRosa26-tdTomato mice). This enabled us to determine whether CD34+ derived cells found in the vein after grafting originated from the donor mouse or from the host. Grafts were explanted 4wks after surgery and analysed by immunohistology and single cell RNA sequencing to resolve cell-level gene expression. Cells from vein grafts were also cultured in vitro and proliferation/differentiation assays were carried out on purified CD34+ cells. Results 70% of cells in the vein graft neointima were derived from CD34+ graft lineage whereas there was no significant contribution of recipient-derived stem cells or bone marrow cells to the neointima. Vein graft neointima smooth muscle cells (SMC) are not stem cells derived. CD34+ stem cells differentiated predominantly into fibroblasts which induced vein SMC phenotype switching and proliferation. Conclusion The majority of CD34+ stem cells found in the neointima of veins, grafted into the arterial circulation were derived from the resident cell population. These cells

Microembolizations in the Arterial Cerebral Circulation in Patients with Atrial Fibrillation Ablation Using the Cryoballoon Technique-Protocol and Methodology of a Prospective Observational Study.

There is considerable uncertainty regarding the impact of microembolic signals (MESs) on neuropsychological abilities in patients receiving pulmonary vein isolation and beyond using the cryoballoon technique. We conducted the largest prospective observational study on this topic, providing insights into the gradual unmasking of procedure-related MESs and their impacts on neuropsychological outcomes. MESs were continuously detected periprocedurally using transcranial Doppler ultrasonography. Neuropsychological status was evaluated comprehensively using the CERAD Plus test battery, which consists of 11 neuropsychological subtests. Patients with atrial fibrillation were included in the study with an equal distribution (50:50) of paroxysmal or persistent presentations. Of 167 consecutive eligible patients, 100 were included within the study enrollment period from February 2021 to August 2022. The study, including the documentation of all follow-up visits, ended in November 2022. This paper focuses on describing the study protocol and methodology and presenting the baseline data.

Hemodynamic Parameters in the Parent Arteries of Unruptured Intracranial Aneurysms Depend on Aneurysm Size and Are Different Compared to Contralateral Arteries: A 7 Tesla 4D Flow MRI Study.

Different Circle of Willis (CoW) variants have variable prevalences of aneurysm development, but the hemodynamic variation along the CoW and its relation to presence and size of unruptured intracranial aneurysms (UIAs) are not well known. Gain insight into hemodynamic imaging markers of the CoW for UIA development by comparing these outcomes to the corresponding contralateral artery without an UIA using 4D flow magnetic resonance imaging (MRI). Retrospective, cross-sectional study. Thirty-eight patients with an UIA, whereby 27 were women and a mean age of 62 years old. Four-dimensional phase-contrast (PC) MRI with a 3D time-resolved velocity encoded gradient echo sequence at 7 T. Hemodynamic parameters (blood flow, velocity pulsatility index [vPI], mean velocity, distensibility, and wall shear stress [peak systolic (WSSMAX ), and time-averaged (WSSMEAN )]) in the parent artery of the UIA were compared to the corresponding contralateral artery without an UIA and were related to UIA size. Paired t-tests and Pearson Correlation tests. The threshold for statistical significance was P < 0.05 (two-tailed). Blood flow, mean velocity, WSSMAX , and WSSMEAN were significantly higher, while vPI was lower, in the parent artery relative to contralateral artery. The WSSMAX of the parent artery significantly increased linearly while the WSSMEAN decreased linearly with increasing UIA size. Hemodynamic parameters and WSS differ between parent vessels of UIAs and corresponding contralateral vessels. WSS correlates with UIA size, supporting a potential hemodynamic role in aneurysm pathology. 2 TECHNICAL EFFICACY: Stage 2.

Late-onset vascular complications of radiotherapy for primary brain tumors: a case–control and cross-sectional analysis

PurposeRadiotherapy (RT) is a recognized risk factor for cerebrovascular (CV) disease in children and in adults with head and neck cancer. We aimed to investigate whether cerebral RT increases the risk of CV disease in adults with primary brain tumors (PBT).MethodsWe retrospectively identified adults with a supratentorial PBT diagnosed between 1975 and 2006 and with at least 10 years follow-up after treatment. We analyzed demographic, clinical, and radiological features with special attention to CV events. We also described CV events, vascular risk factors, and intracranial artery modifications in a cross-sectional study of irradiated patients alive at the time of the study.ResultsA total of 116 patients, treated with RT (exposed group), and 85 non-irradiated patients (unexposed group) were enrolled. Stroke was more frequent in irradiated PBT patients than in the unexposed group (42/116 (36%) vs 7/85 (8%); p < 0.001), with higher prevalence of both ischemic (27/116 (23%) vs 6/85 (7%); p = 0.004) and hemorrhagic (12/116 (10%) vs 1/85 (1%); p = 0.02) stroke. In the irradiated group, patients with tumors near the Willis Polygon were more likely to experience stroke (p < 0.016). Fourty-four alive irradiated patients were included in the cross-sectional study. In this subgroup, intracranial arterial stenosis was more prevalent (11/45, 24%) compared to general population (9%).ConclusionsStroke prevalence is increased in long-surviving PBT patients treated with cranial RT.Implications for cancer survivorsCV events are frequent in long survivors of PBT treated with cerebral RT. We propose a check list to guide management of late CV complications in adults treated with RT for PBT.

Intracranial Aneurysms: Relevance of Superposed Blood Pulse Waves and Tobacco Smoke?

Background: Intracranial aneurysms (IAs) are found in around 3–4% of elderly people. The authors attempt to answer why IAs develop exclusively in the circle of Willis (CW) and why IAs in the frontal cerebral arteries are unusually frequent in men. Methods: The location and frequency of IAs were analyzed using relevant publications (MEDLINE and PubMed). Results: It is suggested that superposed blood pulse waves may have an influence on the development of IAs. The superposition of blood pulse waves is caused by the meeting of the bilateral cerebral arteries in the CW. The predominance of IAs in women is striking (about 1.7:1). However, IAs in the anterior cerebral arteries and anterior communicating artery are significantly more common in men than in women (approximately 1.8:1). The authors hypothesize that greater nicotine abuse in men may explain this phenomenon. Cigarette smoke apparently reaches the anterior cerebral arteries via the olfactory pathway. Conclusion: It seems possible that superposed pulse waves are a substantial factor in the occurrence of IAs. The toxic effects of tobacco smoke appear to have greater impact on IA development than the sex-specific influences that are responsible for the predominance of IAs in women.

Preventing Postoperative Apoplexy in Giant Pituitary Adenomas using Combined Trans-Sphenoidal and Cranial Surgery.

Combined surgery consisting of endoscopic trans-sphenoidal surgery (ETSS) and transcranial (TC) surgery for giant pituitary adenomas (GPAs) has been recommended to prevent lethal postoperative apoplexy. Based on our experience, we attempt to rationalize the indications for such surgery. We report the magnetic resonance (MR) characteristics of the tumor and the outcomes in patients with GPAs who underwent ETSS only and combined surgery. Total tumor volume (TTV), tumor extension volume (TEV), and suprasellar extension of tumor (SET) were calculated based on the lines drawn on MR images and compared between those who underwent ETSS only and those who underwent combined surgery. Of 80 patients with GPAs, eight (10%) underwent combined surgery (seven in the same sitting and one had staged surgery). All eight patients (100%) who underwent combined surgery had tumors with multilobulations, extensions, and encasement of the vessels in the circle of Willis (COW). Of 72 patients who underwent ETSS alone, 21 (29.1%) had a multilobulated tumor, 26 (36.2%) tumors had anterior/lateral extensions, and 12 (16.6%) had encasement of the COW. The mean TTV, TEV, and SET for the combined surgery group were significantly higher than those in the ETSS group. None of the patients who underwent combined surgery suffered postoperative residual tumor apoplexy. Patients with GPAs in whom there are significant lateral intradural or subfrontal tumor extensions should be considered for combined surgery at the same sitting to avoid devastating postoperative apoplexy in the residual tumor, which can occur when ETSS alone is performed.

Follow the MAPCA: an unusual source of right pulmonary artery flow.

Major aortopulmonary collateral arteries in the setting of pulmonary atresia with intact ventricular septum are very rarely encountered, having been documented in only a handful of case reports. We present the right ventriculogram of a patient found to have this rare combination of findings along with right ventricular-dependent coronary artery circulation and unusual supply of the right pulmonary artery.

Omental arteriovenous fistula after splenectomy treated with transarterial embolization

BackgroundLaparoscopic splenectomy for patients with portal hypertension is associated with a high risk of bleeding. The use of vessel-sealing devices and automatic sutures is important for bleeding control. However, a rare complication of abdominal surgery is the direct communication between the arterial and portal circulation related to surgical procedures such as simultaneous ligature of an artery and adjacent vein. We describe a rare case of omental arteriovenous fistula (AVF) after laparoscopic splenectomy treated with transarterial embolization.Case presentationWe report a case of a 46-year-old male patient with an omental AVF after a laparoscopic splenectomy 6 years ago for splenomegaly associated with alcoholic cirrhosis. Follow-up abdominal dynamic computed tomography accidentally revealed a vascular sac (25 mm in the major axis) that formed an omental AVF with anastomosis to the left colonic vein. The communication was considered to be caused by using a vessel-sealing device. No symptoms related to the AVF were observed. The AVF was embolized with microcoils using the transarterial approach. A 4-axis catheter system was used for accurate embolization due to the long and tortuous distance from the celiac artery. No recurrence or symptoms were observed after 6 months.ConclusionsTreatment of arterioportal fistula is mandatory, even in asymptomatic patients. Embolization is a less invasive alternative to surgical approaches. The 4-axis catheter system was useful for accurate embolization via a long and tortuous artery.

Impact of Circle of Willis Anatomical Variations on Outcomes in Aneurysmal Subarachnoid Hemorrhage (P7-5.027)

<h3>Objective:</h3> We sought to determine the association between circle of Willis (CoW) anatomical variations and outcomes in aneurysmal subarachnoid hemorrhage (aSAH) patients. <h3>Background:</h3> The impact of CoW anatomical variations on vasospasm risk and functional outcome in patients with aSAH is poorly understood. <h3>Design/Methods:</h3> We performed a retrospective study on a single center cohort of patients with aSAH admitted to an academic center between 2015 and 2022. After reviewing imaging, we classified CoW variants into 4 categories: 1) incomplete anterior segments if either proximal anterior cerebral or anterior communicating arteries were absent or hypoplastic (with a 1mm diameter cutoff), 2) incomplete posterior segments if posterior communicating or proximal posterior cerebral arteries were absent or hypoplastic; 3) complete CoW; 4) others. Outcomes include vasospasm based on transcranial Doppler (TCD) criteria and poor functional outcome defined as modified Rankin Scale 4–6 at 3 months post discharge. Binary logistic regression analysis was used to test the association of each CoW variant with outcomes. <h3>Results:</h3> We included 178 patients with aSAH (mean age 55.9 years [SD 13.6], 56% female). Eighty percent of patients had incomplete CoW and they were older than those with complete CoW (mean age 57.4 [SD12.7] vs 49.9 [15.4]; p=0.003). Incomplete posterior segments were seen in 73% of patients. The presence of incomplete anterior segments was more common in females (11% vs 1%; p=0.01) and it was associated with vasospasm (OR 2.39, 95% CI 1.02–5.63; p=0.042), but not with poor functional outcome (p=0.89). There was no association between incomplete posterior segments and vasospasm risk (p=0.29) or poor functional outcome (p=0.93). <h3>Conclusions:</h3> Anatomical variations of the CoW may affect TCD findings but did not appear to be associated with poor outcomes. Larger prospective studies are needed to explore clinical significance of CoW variants in aSAH patients. <b>Disclosure:</b> Scott Moody has nothing to disclose. Mr. Pham has nothing to disclose. Mr. Ozcan has nothing to disclose. Miss Haripottawekul has nothing to disclose. Dr. Subramaniam has nothing to disclose. Dr. Reznik has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Morrison Mahoney. The institution of Dr. Reznik has received research support from NIDUS. The institution of Dr. Furie has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Janssen/BMS. The institution of Dr. Furie has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for ACTICOR. Dr. Furie has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for BMJ/JNNP. The institution of Dr. Furie has received research support from NINDS. Dr. Yaghi has nothing to disclose. Dr. Mahta has nothing to disclose.

Pulmonary artery pulsatility index in patients with tricuspid valve regurgitation: a simple non-invasive tool for risk stratification.

Tricuspid valve regurgitation (TR) is a common valvular disease associated with increased mortality. There is a need for tools to assess the interaction between the pulmonary artery (PA) circulation and the right ventricle in patients with TR and to investigate their association with outcomes. The pulmonary artery pulsatility index (PAPi) has emerged as a haemodynamic risk predictor in left heart disease and pulmonary hypertension (PH). Whether PAPi discriminates risk in unselected patients with greater than or equal to moderate TR is unknown. In 5079 patients with greater than or equal to moderate TR (regardless of aetiology) and PA systolic and diastolic pressures measured on their first echocardiogram, we compared all-cause mortality at 5 years based on the presence or absence of PH and PAPi levels. A total of 2741 (54%) patients had PH. The median PAPi was 3.0 (IQR 1.9, 4.4). Both the presence of PH and decreasing levels of PAPi were associated with larger right ventricles, worse right ventricular systolic function, higher NT-pro BNP levels, greater degrees of right heart failure, and worse survival. In a subset of patients who had an echo and right heart catheterization within 24 h, the correlation of non-invasive to invasive PA pressures and PAPi levels was very good (r = 0.76). In patients with greater than or equal to moderate TR with and without PH, lower PAPi is associated with right ventricular dysfunction, right heart failure, and worse survival. Incorporating PA pressure and PAPi may help stratify disease severity in patients with greater than or equal to moderate TR regardless of aetiology.

Prognostic value of perioperative change of neutrophil elastase and myeloperoxidase in coronary circulation on perioperative myocardial injury and clinical outcome of patients underwent surgical valve replacement

Objective: To investigate the clinical value of observing perioperative changes of myeloperoxidase (MPO) and neutrophil elastase (NE) in coronary artery circulation in patients underwent valve replacement surgery. Methods: This perspective cohort study was performed in patients who underwent valvular surgery in Nanjing Drum Tower Hospital and Fuwai Hospital from June 2021 to June 2022. Patients were divided into perioperative myocardial injury group and age-, sex- and type of cardiac procedure-matched non-perioperative myocardial injury control group in the ratio of 1∶1. Perioperative myocardial injury was defined as cardiac troponin T (cTnT)>0.8 μg/L on the first postoperative day (POD), and the cTnT level on the second POD increased by more than 10% compared with the cTnT level on the first POD. During the operation, blood samples were collected from the coronary sinus before clamping ascending aorta, and within 5 minutes after de-clamping ascending aorta. Then, the levels of MPO and NE on coronary sinus were continuously measured. The death, severe ventricular arrhythmia, pneumonia, re-intubation, repeat cardiac surgery, extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump (IABP), continuous renal replacement therapy (CRRT), mechanical ventilation time and the duration of intensive care unit (ICU) were recorded. The levels of MPO and NE and the incidence of clinical outcomes were compared between the myocardial injury group and the control group. The independent risk factors of myocardial injury were analyzed by multivariate logistic regression. Results: A total of 130 patients were enrolled, aged (60.6±7.6) years old, with 59 males (45.4%). There were 65 patients in the myocardial injury group and 65 patients in the control group. During hospitalization, there was no death, ECMO, IABP and CRRT cases in both groups. Compared with the control group, the incidence of severe ventricular arrhythmia (13.8%(9/65) vs. 3.1%(2/65), P=0.03), pneumonia (20.0%(13/65) vs. 3.1%(2/65), P=0.03), re-intubation (6.2%(4/65) vs. 0, P=0.04) was significantly higher in myocardial injury group. The mechanical ventilation time (16.8(10.7, 101.7) h vs. 7.5(4.7, 15.1) h, P<0.01), and the duration of ICU (3.7(2.7, 18.9) vs. 2.7(1.8, 6.9)d, P<0.01) were significantly longer in myocardial injury group compared with the control group. There was no significant difference in the levels of MPO and NE in coronary sinus blood between the two groups before aortic clamping (all P>0.05). However, MPO ((551.3±124.2) μg/L vs. (447.2±135.9) μg/L, P<0.01) and NE ((417.0±83.1)μg/L vs. (341.0±68.3)μg/L, P<0.01) after 5 min aortic de-clamping were significantly higher in myocardial injury group than in the control group. Multivariate logistic regression analysis showed that the levels of NE (OR=1.02, 95%CI: 1.01-1.02, P<0.01), MPO (OR=1.00, 95%CI: 1.00-1.01, P=0.02) and mechanical ventilation time (OR=1.03, 95%CI: 1.01-1.06, P=0.02) were independent risk factors of myocardial injury in patients after surgical valvular replacement. Conclusion: Perioperative myocardial injury is related poor clinical outcomes, perioperative NE and MPO in coronary artery circulation are independent risk factors of perioperative myocardial injury in patients undergoing valve replacement surgery.

Systematic Review of Morphometric Analysis of Anterior Cerebral Artery (ACA) Emphasizing on Its Clinical Implications.

Thoroughdataof morphometric measurements of arteries forming Circle of Willis (CW)is crucialforradiologicaland neurosurgical interventions. This systematic review has been conducted with the objective to find an effective range of length and diameter of anterior cerebral artery (ACA) and to observe whether there is any change in the length and diameter of ACA depending on age or sex. Articles based on length and diameter of ACA via any mode of study like cadaveric or radiological were considered in this systematic review. A comprehensive literature search using databases Cochrane Library, PubMed, and Scopus for relevant articles was done. Research papers which answered the focused questions were selectedfor data analysis. It was observed that the range of length and diameter of ACA were 8.1 mm-21 mm and 0.5 Å-3.4 mm, respectively. In majority of the studies, length and diameter of ACA were more in the younger age group (>40 years); and the length of ACA was more in females whereas the diameter of ACA was more in males. These data will be applicable for better construction and decipherment of angiographic images. This will help in the proper and guided treatment of intracranial pathologies.

Influence of hydrodynamic and functional nonlinearities of blood flow in the cerebral vasculature on cerebral perfusion and autoregulation pressure reserve

Ensuring the transport of oxygenated blood to the brain is one of the priorities of the human body. In the literature, there are many models of cerebral circulation with different levels of complexity used to assess pathological conditions, support clinical decisions, and learn about the relationships governing cerebral circulation. This paper presents a zero-dimensional cerebral circulation model that considers hydrodynamic nonlinearities and autoregulation mechanisms. The model has been verified using a computational fluid dynamics (CFD) model of the Circle of Willis (CoW) and its supplying and outgoing branches. Despite the considerable simplicity, the presented model captured the dominant features of cerebral circulation and provides good agreement with the CFD model. The errors in relation to the CFD model did not exceed 2.6% and 9.9% for the symmetrical and highly asymmetrical CoW configurations, respectively. The practical application of the model was demonstrated for predicting the autoregulation pressure reserve for different diameters of natural anastomoses: Posterior and Anterior Communicating Arteries. The advantages and limitations of the model were discussed.

Hemodynamic characteristics and mechanism for intracranial aneurysms initiation with the circle of Willis anomaly

Clinically, circle of Willis (CoW) is prone to anomaly and is also the predominant incidence site of intracranial aneurysms (IAs). This study aims to investigate the hemodynamic characteristics of CoW anomaly, and ascertain the mechanism of IAs initiation from the perspective of hemodynamics. Thus, the flow of IAs and pre-IAs were analyzed for one type of cerebral artery anomaly, that is, anterior cerebral artery A1 segment (ACA-A1) unilateral absence. Three patient geometrical models with IAs were selected from Emory University Open Source Data Center. IAs were virtually removed from the geometrical models to simulate the pre-IAs geometry. For calculation methods, a one-dimensional (1-D) solver and a three-dimensional (3-D) solver were combined to obtain the hemodynamic characteristics. The numerical simulation revealed that the average flow of Anterior Communicating Artery (ACoA) is almost zero when CoW is complete. In contrast, ACoA flow increases significantly in the case of ACA-A1 unilateral absence. For per-IAs geometry, the jet flow is found at the bifurcation between contralateral ACA-A1 and ACoA, which exhibits characteristics of high Wall Shear Stress (WSS) and high wall pressure in the impact region. It triggers the initiation of IAs from the perspective of hemodynamics. The vascular anomaly that leads to jet flow should be considered as a risk factor for IAs initiation.

The effect of atypical arterial vascularization of the liver on computed tomography signs of hemangiomas

Introduction. The article describes the role of computed tomography in the diagnosis of hemangiomas in various types of hepatic arterial circulation. Aim. To determine the features of contrast enhancement of hemangiomas in multislice computed tomography with multiphase contrast enhancement in patients with abnormalities of the arterial supplement of the liver. Materials and methods. The results of 60 computed tomographic angiographies of patients with hemangiomas of various sizes (mean age of patients 59.2±12.3 years, the study included 34 (57 %) men, 26 (43 %) women) were analyzed. Results. The most common anatomical variants of the vasculature, concomitant anomalies of the arterial supply of other abdominal organs, as well as features of contrast enhancement of hemangiomas depending on their size are described. The analysis of vascular architectonics revealed that the first type of arterial supply according to Mitchels (p &lt;0.05) ) is prevailed, however, 3 (3.3 %), 5 (3.3 %), 6 (6.6 %) types were also determined. Thus, a correlation analysis using Fisher’s exact test was not detected a significant correlation between the presence of hemangiomas in the liver parenchyma and the presence of aberrant (r=0.11, p=0.36) or replacement arterial vessels (r=0.14, p=0.35). At the same time, when visually assessing the contrast enhancement of hemangiomas in different phases of contrast enhancement, both in the presence of aberrant and replacing vessels and without them, the main radiation patterns of changing hemangiomas density remained unchanged. Conclusion. Based on the obtained data on the liver arterial system, the absence of a significant correlation between the type of arterial blood supply, the presence of an additional or replacement vessel, and the type of contrast enhancement of hemangiomas during multiphase computed tomography of the abdominal organs was demonstrated.

Investigating spatial variations in dynamic cerebral autoregulation through a computational model of stenosis

Objective. Dynamic cerebral autoregulation (dCA) is a well-established mechanism that acts to maintain cerebral blood flow (CBF) reasonably constant in response to short-term fluctuations in blood pressure. It is known to be impaired in many clinical conditions, including stenosis, which is also a major risk factor for ischaemic stroke. However, it is not yet well understood whether impairment in dCA in one brain region is independent or not on dCA impairment in other brain regions, for example, whether there are spatial effects of stenosis on dCA. This is due to the complex blood flow environment and the lack of physiological experiments. Approach. We thus establish and apply a novel computational stenosis model including the circle of Willis to investigate and to quantify the degree of dCA impairment and CBF patterns as a function of stenosis fraction, measured in different configurations of the cerebral vasculature. Main results. We find some evidence for dependence between dCA in different brain regions, although this is very preliminary and much more experimental data will be required to answer this question fully. Significance. Our study has provided a first attempt to consider the effect of stenosis in various arteries on cerebral autoregulation to investigate spatial variations in dCA. This has potential applications in the treatment of cerebrovascular diseases where the control of cerebral perfusion is critical but where measurements are scarce.

Effect of Coronary Artery Dominance In-terms of Presentation and In-hospital Outcomes of patients undergoing Primary PCI for Culprit Proximal Left Anterior Descending Artery

Objectives: Objective of this study was to assess the difference in terms of presentation and in-hospital course between patients with right vs. left dominant arterial circulation undergoing “primary percutaneous coronary intervention (PCI)” for culprit proximal left anterior descending artery (LAD). Methodology: We included consecutive adult (≥18 years) patients diagnosed with STE-ACS undergoing primary PCI for culprit proximal LAD. Patients were categorized into right vs. left dominant circulation on left heart catheterization. Demographic, clinical characteristics, presentation, and hospital course were compared between the matched (propensity matched) and unmatched cohort of patients with right vs. left dominance. Results: We included 775 patients, out of which 81.3% (630) were males and mean age was 54.59 ± 11.3 years. On coronary angiogram left dominance was observed in 14.3% (111). Single vessel disease was higher with left compared to right dominant system, 53.2% vs. 43.5%, respectively. The rate of slow flow/no-reflow (15.4% vs. 7.2%; p=0.0.230), heart failure (9.3% vs. 6.3%; p=0.299), and in-hospital mortality (5.1% vs. 3.6%, p=0.493) were not different between right vs. left dominance, respectively. In the matched cohorts, the frequency of slow flow/no-reflow (15.3% vs. 7.2%; p=0.056), heart failure (6.3% vs. 6.3%; p&gt;0.999), and mortality (5.4% vs. 3.6%, p=0.493) were not different between right vs. left dominance, respectively. Conclusion: No significant increase in complications and outcomes is witnessed among patients with left dominant arterial circulation undergoing primary PCI for culprit proximal LAD. However, careful handling of left main during intervention is warranted due lack of support from right system.

VARIANTS OF THE CIRCLE OF WILLIS ON NON-CONTRAST MAGNETIC RESONANCE ANGIOGRAPHY

Background: The Circle of Willis (CoW) distributes oxygenated blood throughout the brain and represents the only major anastomosis of the brain. The study of variations in CoW is crucial for avoiding confusion of the anomalies with aneurysms, evaluating collateral pathways in the intracerebral circulation, and enhancing pre-operative planning in patients undergoing surgery at the skull base. Objectives: Evaluate and describe the prevalence of variations of the CoW by using three-dimensional time-of-flight MR angiography (3D-TOF-MRA). Materials and methods: We conducted a cross-sectional description in 102 patients after meeting the requirements of inclusion criteria. All participants were scanned in a GE Optima 360 1.5T MRI scanner. The variants of the CoW were studied. The correlation between variations in relation to gender and age were evaluated. Results: Among 102 samples, the mean age was 46, and female dominance was seen among participants (60.80%). The proportion of CoW with normal shape (7 edges) as in classical anatomy is 10.78%. The highest prevalence of variations was seen in PCOM-R with 62.75% (64/102) and PCOM-L with 58.82% (60/102). We recorded 32 types of CoW variation, including 7 single variants accounting for 26.37% (24/91) and 25 combined variants with 73.63% (67/91), some of which had not been reported in previous studies. Conclusion: The complete configuration of the CoW was seen in 10.78% of population. 32 types of CoW variation, including 7 single variants (26.37%) and 25 combined variants (73.63%) were recorded.

Blood supply to the cranial cavity in the patagonian mara (Dolichotis patagonum)

Rodents are the most numerous order of mammals. The literature presents information on the arterial circle of the brain in capybara, the guinea pig of the family Caviidae and many other not so closely related rodent species. Information on the blood supply to the brain is often incomplete and focuses on one pathway in a broader comparative aspect. The supply of oxygen and nutrients to the brain is very important for its proper functioning. The aim of this study is to describe the pathways supplying blood to the cranial cavity and to describe the arterial circle of the brain in the Patagonian mara. The study was conducted on 46 specimens using two methods. The first of them used a stained solution of the chemo-setting acrylic material. The second one, the colored liquid LBS 3060 latex. The arterial circle of the brain is a heart-shaped structure. It is formed by rostral cerebral arteries, caudal communicating arteries and the basilar artery. Blood supplies the arterial circle of the brain in three ways. First one is the basilar artery, which originates from the vertebral arteries. The second one is the internal carotid artery which joins a branch from the external ophthalmic artery. The third is the internal ophthalmic artery, which branches from the external ophthalmic artery.