scholarly journals Numerical Modeling of Vascular Stresses During Lead Extraction: Subclavian vs. Femoral

2020 ◽  
Author(s):  
Mostafa Toloui ◽  
Mark Marshall ◽  
Pierce Vatterott ◽  
Peter Zhang ◽  
Ryan Lahm ◽  
...  
Keyword(s):  
Femoral Vein ◽  
High Stress ◽  
Wall Stress ◽  
Extraction Methods ◽  
Lead Extraction ◽  
Vein Wall ◽  
Femoral Approach ◽  
Stress Levels ◽  
Lead Management ◽  
The Individual

Abstract Transvenous lead extraction is a critical and growing technique used to treat patients with chronically implanted pacemakers and defibrillators. This procedure is commonly executed via the subclavian vein or the femoral vein. Some physicians’ experiences indicate that the femoral approach results in fewer vascular tears. This study is aimed to present a physics-based comparative assessment of intravenous mechanical stresses for chronic lead management between the two approaches. Finite Element (FE) modeling is employed to quantify the vascular stress distributions. A full 3-D model including veins, heart, fibrotic scar regions and the lead was created to simulate the different lead extraction methods. Results: (1) highest stresses are generally in the vicinity of SVC lead attachments; (2) femoral approach results in a ∼uniform distribution of stress over the scar while the subclavian approach leads to patches of concentrated high stress; (3) 2–3 times higher maximum vascular stress during subclavian; (4) insignificant maximum stress at the apex for both; (5) inverse variation of stress levels with: (i) branch-to-scar distance for SVC method; and (ii)vein wall thickness in both methods. (6) lower stress levels for scars with longer attachment lengths. The importance and effectiveness of mechanical stress analysis in risk analysis for chronic lead management is illustrated. Overall, the localized intravascular wall stress is meaningfully higher for subclavian vs. femoral extraction with same SVC shear force. This may help explain the higher rate of SVC tears when extracting from the left subclavian approach. The individual anatomy (e.g. vascular angles) is a key factor in the resulting stress and this understanding may be critical when choosing an extraction approach and future lead design.

Biomechanical response of femoral vein to chronic elevation of blood pressure in rabbits

2003 ◽  
Vol 284 (2) ◽  
pp. H511-H518 ◽  
Author(s):  
K. Hayashi ◽  
K. Mori ◽  
H. Miyazaki
Keyword(s):  
Blood Pressure ◽  
Femoral Vein ◽  
Control Level ◽  
Wall Stress ◽  
Venous Hypertension ◽  
Vein Wall ◽  
Blood Pressure Elevation ◽  
Pressure Elevation ◽  
Venous Diseases

Venous diseases like iliofemoral deep vein thrombosis and valvular dysfunction induce venous hypertension. To know the effects of the hypertension on venous mechanics, blood pressure in the left femoral vein in the rabbit was chronically elevated by the constriction of the left external iliac vein. Wall dimensions and biomechanical properties of the femoral vein were studied in vitro at 1, 2, or 4 wk after surgery. Blood pressure measured immediately before the animal was killed was significantly higher in the left femoral vein than in the sham-operated, contralateral vein. Wall thickness was increased by blood pressure elevation even at 1 wk, which restored circumferential wall stress to a control level. The stress was kept at normal up to 4 wk. Vascular tone and vascular contractility were increased by the elevation of blood pressure; however, wall elasticity and compliance were kept at a normal level. These results are very similar to those observed in hypertensive arteries, indicating that not only arteries but veins optimally operate against blood pressure elevation.

Internal valvuloplasty combined with sleeve wrapping in the treatment of severe deep venous incompetence: A case report

Vascular ◽  
2021 ◽  
pp. 170853812199012
Author(s):  
Yingfeng Wu ◽  
Libing Wei ◽  
Xixiang Gao ◽  
Yixia Qi ◽  
Zhu Tong ◽  
...  
Keyword(s):  
Lower Limb ◽  
Venous Insufficiency ◽  
Femoral Vein ◽  
Duplex Ultrasound ◽  
Vein Wall ◽  
Polyester Urethane ◽  
Left Lower Limb ◽  
Deep Vein ◽  
Color Duplex Ultrasound

Background The main cause of severe chronic venous insufficiency is deep venous incompetence. Deep venous reconstructive surgeries are reserved for cases that do not show a good response to conservative therapies. Method We present the case of a 68-year-old man presenting with swelling, pain, and pigmentation in his left lower limb for 14 years and ulcers for 10 years. Descending venography identified a Kistner’s grade IV reflux in the deep vein of the left lower limb. Internal valvuloplasty was performed following Kistner’s method. Meanwhile, external wrapping with a 1-cm-wide polyester-urethane vascular patch was performed to strengthen the vein wall in the venospasm condition. Results Symptoms were immediately relieved postoperatively. Refractory ulcers healed five months after the procedure. At the six-month follow-up, color duplex ultrasound of the deep vein of the left lower limb showed no reflux in the proximal segment of the femoral vein. Conclusion Internal valvuloplasty combined with sleeve wrapping is feasible in the treatment of severe deep venous incompetence with good short-term results.

scholarly journals Biological Effect of Different Spinach Extracts in Comparison with the Individual Components of the Phytocomplex

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 382
Author(s):  
Laura Arru ◽  
Francesca Mussi ◽  
Luca Forti ◽  
Annamaria Buschini
Keyword(s):  
Antioxidant Defense ◽  
Extraction Methods ◽  
Oxidizing Agent ◽  
Endogenous Reactive Oxygen Species ◽  
Dependent Activity ◽  
Main Components ◽  
The Individual ◽  
Dose Dependent ◽  
Higher Doses ◽  
Oxidative Insult

The Mediterranean-style diet is rich in fruit and vegetables and has a great impact on the prevention of major chronic diseases, such as cardiovascular diseases and cancer. In this work we investigated the ability of spinach extracts obtained by different extraction methods and of the single main components of the phytocomplex, alone or mixed, to modulate proliferation, antioxidant defense, and genotoxicity of HT29 human colorectal cells. Spinach extracts show dose-dependent activity, increasing the level of intracellular endogenous reactive oxygen species (ROS) when tested at higher doses. In the presence of oxidative stress, the activity is related to the oxidizing agent involved (H2O2 or menadione) and by the extraction method. The single components of the phytocomplex, alone or mixed, do not alter the intracellular endogenous level of ROS but again, in the presence of an oxidative insult, the modulation of antioxidant defense depends on the oxidizing agent used. The application of the phytocomplex extracts seem to be more effective than the application of the single phytocomplex components.

The flow of glass at high stress levels

1970 ◽  
Vol 3 (1) ◽  
pp. 127-147 ◽  
Author(s):  
J.H. Li ◽  
D.R. Uhlmann
Keyword(s):  
High Stress ◽  
Stress Levels

scholarly journals Excimer laser lead extraction by femoral approach

EP Europace ◽  
2010 ◽  
Vol 13 (5) ◽  
pp. 757-759 ◽  
Author(s):  
I. Diemberger ◽  
M. Biffi ◽  
C. Martignani ◽  
G. Boriani
Keyword(s):  
Excimer Laser ◽  
Lead Extraction ◽  
Femoral Approach ◽  
Laser Lead Extraction

scholarly journals Crowd behaviour during high-stress evacuations in an immersive virtual environment

2016 ◽  
Vol 13 (122) ◽  
pp. 20160414 ◽  
Author(s):  
Mehdi Moussaïd ◽  
Mubbasir Kapadia ◽  
Tyler Thrash ◽  
Robert W. Sumner ◽  
Markus Gross ◽  
...  
Keyword(s):  
Virtual Environments ◽  
Virtual Environment ◽  
Human Subjects ◽  
High Stress ◽  
Three Dimensional ◽  
Real Life ◽  
Social Conventions ◽  
Emergency Situations ◽  
Crowd Behaviour ◽  
The Individual

Understanding the collective dynamics of crowd movements during stressful emergency situations is central to reducing the risk of deadly crowd disasters. Yet, their systematic experimental study remains a challenging open problem due to ethical and methodological constraints. In this paper, we demonstrate the viability of shared three-dimensional virtual environments as an experimental platform for conducting crowd experiments with real people. In particular, we show that crowds of real human subjects moving and interacting in an immersive three-dimensional virtual environment exhibit typical patterns of real crowds as observed in real-life crowded situations. These include the manifestation of social conventions and the emergence of self-organized patterns during egress scenarios. High-stress evacuation experiments conducted in this virtual environment reveal movements characterized by mass herding and dangerous overcrowding as they occur in crowd disasters. We describe the behavioural mechanisms at play under such extreme conditions and identify critical zones where overcrowding may occur. Furthermore, we show that herding spontaneously emerges from a density effect without the need to assume an increase of the individual tendency to imitate peers. Our experiments reveal the promise of immersive virtual environments as an ethical, cost-efficient, yet accurate platform for exploring crowd behaviour in high-risk situations with real human subjects.

scholarly journals FBSEM: A Novel Feature-Based Stacked Ensemble Method for Sentiment Analysis

2020 ◽  
Vol 12 (6) ◽  
pp. 11-22
Author(s):  
Yasin Görmez ◽  
◽  
Yunus E. Işık ◽  
Mustafa Temiz ◽  
Zafer Aydın
Keyword(s):  
Sentiment Analysis ◽  
Cross Validation ◽  
Emotional State ◽  
Ensemble Methods ◽  
Extraction Methods ◽  
Error Rates ◽  
Ensemble Method ◽  
Learning Tasks ◽  
Feature Based ◽  
The Individual

Sentiment analysis is the process of determining the attitude or the emotional state of a text automatically. Many algorithms are proposed for this task including ensemble methods, which have the potential to decrease error rates of the individual base learners considerably. In many machine learning tasks and especially in sentiment analysis, extracting informative features is as important as developing sophisticated classifiers. In this study, a stacked ensemble method is proposed for sentiment analysis, which systematically combines six feature extraction methods and three classifiers. The proposed method obtains cross-validation accuracies of 89.6%, 90.7% and 67.2% on large movie, Turkish movie and SemEval-2017 datasets, respectively, outperforming the other classifiers. The accuracy improvements are shown to be statistically significant at the 99% confidence level by performing a Z-test.

scholarly journals Occupational Stress and Job Burnout among Primary and Secondary School Teachers in Cuttack, Orissa, 2013

2017 ◽  
Vol 5 (1) ◽  
Author(s):  
Joyce Mathews
Keyword(s):  
Occupational Stress ◽  
Secondary School Teachers ◽  
Demographic Data ◽  
High Stress ◽  
Job Burnout ◽  
Stress Index ◽  
Stress Levels ◽  
Older Teachers ◽  
The Relationship ◽  
Primary And Secondary School

The purpose of this study was to explore the levels of occupational stress and job burnout among teachers working in primary and secondary schools and identify the relationship between the selected demographic data with the stress levels. The sample consisted of 100 teachers from 4 schools in Cuttack, Orissa. The instruments used to measure the variables were: 1.Headington Stress Index questionnaire, 2.Headingtacon Burnout Inventory, 3. Self care and Lifestyle Balance Inventory. The statistical techniques of descriptive statistics, ANOVA analysis and Pearson’s coefficient were employed to analyze the data. The findings of the study indicated that a major portion of the teachers’ population faced moderately low stress and burnout, and the remaining faced moderately high stress and burnout. Younger teachers are reported to have more stress than the older teachers. Higher the burnout among teachers, lower was the lifestyle balance among them. Experience, gender and grade did not affect the stress levels among teachers.

scholarly journals Psychological Impact of COVID-19 Pandemic on Healthcare Workers in Riyadh, Saudi Arabia: Perceived Stress Scale Measures

2021 ◽  
Vol 11 (4) ◽  
pp. 377-388
Author(s):  
Nuha Alwaqdani ◽  
Hala A. Amer ◽  
Reem Alwaqdani ◽  
Fahad AlMansour ◽  
Hind A. Alzoman ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Perceived Stress ◽  
Online Survey ◽  
High Stress ◽  
Post Traumatic Stress ◽  
Perceived Stress Scale ◽  
Health Crisis ◽  
Stress Scale ◽  
Increased Risk ◽  
Stress Levels

Abstract Background The COVID-19 pandemic has been stressful and of considerable concern among health care workers (HCWs). Being particularly at increased risk for exposure, HCWs worry about becoming infected as well as infecting co-workers, patients and family members. Such distress and panic may have destructive effects on individuals and may last long after the pandemic situation leading to depression or post-traumatic stress disorder. Therefore, the aim of the current study is to measure and investigate the prevalence of the factors affecting psychological stress during the COVID-19 pandemic among HCWs. Methods A self-administered online survey—including perceived stress scale (PSS) questions—was disseminated among HCWs in Riyadh, Saudi Arabia (SA) between1st June and 30th July 2020. Results A total of 469 HCWs responded to the survey for a high response rate (93.8%). The PSS revealed that 15.8% of the respondents were suffering from high stress levels, 77.2% were suffering from moderate stress levels and 7% with low stress levels. Females and junior frontline staff reported more severe stress levels. Participation on the pandemic team shows significant impact on stress levels. Conclusion COVID-19 pandemic has increased stress levels among HCWs and affects their psychological wellbeing. Designing programs promoting HCWs mental health are crucial and emotional and psychological support strategies should be part of every public health crisis management plan.

scholarly journals The major worldwide stress of healthcare professionals during the first wave of the COVID-19 pandemic – the international COVISTRESS survey

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0257840
Author(s):  
Sébastien Couarraze ◽  
Louis Delamarre ◽  
Fouad Marhar ◽  
Binh Quach ◽  
Jiao Jiao ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Protective Factor ◽  
Healthcare Professionals ◽  
High Stress ◽  
Medical Doctors ◽  
Health Crisis ◽  
Paramedical Staff ◽  
Increased Risk ◽  
Stress Levels ◽  
Very High

Introduction The COVID-19 pandemic has initiated an upheaval in society and has been the cause of considerable stress during this period. Healthcare professionals have been on the front line during this health crisis, particularly paramedical staff. The aim of this study was to assess the high level of stress of healthcare workers during the first wave of the pandemic. Materials and methods The COVISTRESS international study is a questionnaire disseminated online collecting demographic and stress-related data over the globe, during the pandemic. Stress levels were evaluated using non-calibrated visual analog scale, from 0 (no stress) to 100 (maximal stress). Results Among the 13,537 individuals from 44 countries who completed the survey from January to June 2020, we included 10,051 workers (including 1379 healthcare workers, 631 medical doctors and 748 paramedical staff). The stress levels during the first wave of the pandemic were 57.8 ± 33 in the whole cohort, 65.3 ± 29.1 in medical doctors, and 73.6 ± 27.7 in paramedical staff. Healthcare professionals and especially paramedical staff had the highest levels of stress (p < 0.001 vs non-healthcare workers). Across all occupational categories, women had systematically significantly higher levels of work-related stress than men (p < 0.001). There was a negative correlation between age and stress level (r = -0.098, p < 0.001). Healthcare professionals demonstrated an increased risk of very-high stress levels (>80) compared to other workers (OR = 2.13, 95% CI 1.87–2.41). Paramedical staff risk for very-high levels of stress was higher than doctors’ (1.88, 1.50–2.34). The risk of high levels of stress also increased in women (1.83, 1.61–2.09; p < 0.001 vs. men) and in people aged <50 (1.45, 1.26–1.66; p < 0.001 vs. aged >50). Conclusions The first wave of the pandemic was a major stressful event for healthcare workers, especially paramedical staff. Among individuals, women were the most at risk while age was a protective factor.

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