Arch vessel injury: geometrical considerations. Implications for the mechanism of traumatic myocardial infarction II

BACKGROUND: Various types of vascular injury have been reported in the medical literature; the isthmic part of the aorta is at particularly high risk of traumatic rupture. Early diagnosis results in better survival, justifying the search for potential risk factors and diagnostic tests. The aim of this research was to investigate the complex mechanism of blunt injury to the vascular wall with particular focus on the branching region of the vessels. Geometric peculiarities were investigated. METHODS: Multi-phase equations have been used. The system of equations with certain boundary conditions was solved numerically by applying the finite-difference method with order of approximation equal to 0.0001. RESULTS: The degree of curvature (the Dean number) is highly informative about the shear stress on the external surface of the vessel. An important function of the blood flow on the external wall is to destroy rouleaux. The viscosity of phase 2 (f(2)) exceeds, by many times, the viscosity of phase 1 (f(1)). The major stress created by blood flow is expressed as the shear stress of f(2). The volume fraction of rouleaux depends to a greater degree on the concentration of erythrocytes (expressed as the viscosity of the mixture) than on the shear stress. The peculiarities of rouleaux formation were assessed and their impact on the local shear stress and, therefore, on the internal wall was determined in relation to the erythrocyte concentration. CONCLUSION: The results of this research take into account certain geometrical peculiarities of the branching part of the vessel. The mathematical model created in this study will improve our understanding of the complex mechanism of blunt injury to the vascular wall and, therefore, conditions such as aortic rupture and traumatic acute myocardial infarction

Geographic altitude, ocular diseases and injuries

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Mathematical model describing erythrocyte sedimentation rate. Implications for blood viscosity changes in traumatic shock and crush syndrome

BACKGROUND: The erythrocyte sedimentation rate (ESR) is a simple and inexpensive laboratory test, which is widespread in clinical practice, for assessing the inflammatory or acute response. This work addresses the theoretical and experimental investigation of sedimentation a single and multiple particles in homogeneous and heterogeneous (multiphase) medium, as it relates to their internal structure (aggregation of solid or deformed particles). METHODS: The equation system has been solved numerically. To choose finite analogs of derivatives we used the schemes of directional differences. RESULTS: (1) Our model takes into account the influence of the vessel wall on group aggregation of particles in tubes as well as the effects of rotation of particles, the constraint coefficient, and viscosity of a mixture as a function of the volume fraction. (2) This model can describe ESR as a function of the velocity of adhesion of erythrocytes; (3) Determination of the ESR is best conducted at certain time intervals, i.e. in a series of periods not exceeding 5 minutes each; (4) Differential diagnosis of various diseases by means of ESR should be performed using the aforementioned timed measurement of ESR; (5) An increase in blood viscosity during trauma results from an increase in rouleaux formation and the time-course method of ESR will be useful in patients with trauma, in particular, with traumatic shock and crush syndrome. CONCLUSION: The mathematical model created in this study used the most fundamental differential equations that have ever been derived to estimate ESR. It may further our understanding of its complex mechanism

Enhancing knowledge and awareness of transthyretin cardiac amyloidosis and shared decision-making among cardiology team members in Colorado, USA via an online educational initiative.

Our project aimed to increase knowledge of non-invasive diagnostic modalities (including bone radiotracer scintigraphy), raise suspicion of transthyretin cardiac amyloidosis (ATTR-CA) and improve cardiology team member's awareness and knowledge of shared decision-making (SDM) as well as the quality of SDM communication between cardiology team members and patients. An online educational module and survey was developed and cardiology team members in Colorado, USA were invited to participate. This online educational module included various important topics related to ATTR-CA (e.g., the cause of ATTR-CA, endomyocardial biopsy, and non-invasive methods to diagnose ATTR-CA) and SDM (e.g., benefits of SDM, the role of SDM in the diagnosis of ATTR-CA, implementation SDM in your cardiology practice and the 3-talk model). There were 34 survey respondents, over one-third of whom were cardiologists. Most respondents agreed on the importance of diagnosing ATTR-CA at the early stage, and about three-quarters of the survey takers agreed that bone scintigraphy can reliably diagnose ATTR-CA without the need for endomyocardial biopsy. Concern for increased time commitment was the leading barrier to the implementation of SDM in respondents' clinical practice. The majority of respondents identified the correct answer regarding ATTR-CA and SDM after reading the online educational module. This improvement in scores after exposure to the online educational module was statistically significant. Baseline knowledge and awareness of various issues related to ATTR-CA was relatively low among cardiology team members. Participants' knowledge was enhanced through our effective online educational program. Prospective educational projects focused on various methods of detecting ATTR-CA as well as other amyloid conditions in diverse clinical settings will remain important

Decompensated heart failure in the setting of kidney dysfunction: a community-wide perspective

BACKGROUND: Patients with heart failure (HF) and kidney disease have a poor long-term outlook which has provided impetus for the identification of factors of prognostic importance and more fully understanding the impact of kidney dysfunction in patients with HF. OBJECTIVES: Our objectives were to describe the characteristics, hospital treatment practices, as well as hospital and long-term outcomes in patients with varying degrees of kidney dysfunction who were hospitalized with acute HF at all medical centers in a large New England metropolitan area. METHODS: Residents of the Worcester metropolitan area hospitalized with clinical findings of decompensated HF at 11 greater Worcester medical centers during 1995 and 2000 comprised the study sample. Kidney function was classified into 4 categories of estimated glomerular filtration rate (eGFR) for purposes of analysis: \u3c30 (n = 569), 30-44 (n = 725), 45-59 (n = 763), and \u3e or =60 (n = 2,293) ml/min per 1.73 m(2). RESULTS: The average age of the study sample was 76 years and 57% were women. Patients with severe kidney dysfunction were less likely to receive angiotensin-converting enzyme inhibitors, diuretics and digoxin during hospitalization for acute HF compared to patients with more normal kidney function. Patients with lower eGFR levels had higher in-hospital and post-discharge death rates in comparison to those with higher levels of eGFR. CONCLUSION: Our results demonstrate the impact of renal impairment on the prognosis of patients with decompensated HF. Our findings highlight the less than optimal management of these high-risk patients. Increased surveillance and enhanced treatment of patients with HF and kidney dysfunction remains warranted to improve the survival outlook of these patients

Blunt trauma to large vessels: a mathematical study

Abstract Background Blunt trauma causes short-term compression of some or all parts of the chest, abdomen or pelvis and changes hemodynamics of the blood. Short-term compression caused by trauma also results in a short-term decrease in the diameter of blood vessels. It has been shown that with a sudden change in the diameter of a tube or in the direction of the flow, the slower-moving fluid near the wall stops or reverses direction, which is known as boundary layer separation (BLS). We hypothesized that a sudden change in the diameter of elastic vessel that results from compression may lead not only to BLS but also to other hemodynamic changes that can damage endothelium. Methods We applied Navier-Stokes, multiphase and boundary layer equations to examine such stress. The method of approximation to solve the BL equations was used. Experiments were conducted in an aerodynamic tube, where incident flow velocity and weight of carriage with particles before and after blowing were measured. Results We found that sudden compression resulting from trauma leads to (1) BLS on the curved surface of the vessel wall; (2) transfer of laminar boundary layer into turbulent boundary layer. Damage to the endothelium can occur if compression is at least 25% and velocity is greater than 2.4 m/s or if compression is at least 10% and velocity is greater than 2.9 m/s. Conclusion Our research may point up new ways of reducing the damage from blunt trauma to large vessels. It has the potential for improvement of safety features of motor vehicles. This work will better our understanding of the precise mechanics and critical variables involved in diagnosis and prevention of blunt trauma to large vessels.</p