Cardiovascular System Commons^™

Ambulatory Systolic Blood Pressure And Obesity Are Independently Associated With Left Ventricular Hypertrophic Remodeling In Children, Linyuan Jing, Christopher D. Nevius, Cassi M. Friday, Jonathan D. Suever, Arichanah Pulenthiran, Abba Mejia-Spiegeler, H. Lester Kirchner, William J. Cochran, Gregory J. Wehner, Aftab S. Chishti, Christopher M. Haggerty, Brandon K. Fornwalt

Biomedical Engineering Faculty Publications

Background: Children with obesity have hypertrophic cardiac remodeling. Hypertension is common in pediatric obesity, and may independently contribute to hypertrophy. We hypothesized that both the degree of obesity and ambulatory blood pressure (ABP) would independently associate with measures of hypertrophic cardiac remodeling in children.

Methods: Children, aged 8–17 years, prospectively underwent cardiovascular magnetic resonance (CMR) and ABP monitoring. Left ventricular (LV) mass indexed to height^2.7(LVMI), myocardial thickness and end-diastolic volume were quantified from a 3D LV model reconstructed from cine balanced steady state free precession images. Categories of remodeling were determined based on cutoff values for LVMI and …

Impaired Right Ventricular Contractile Function In Childhood Obesity And Its Association With Right And Left Ventricular Changes: A Cine Dense Cardiac Magnetic Resonance Study, Linyuan Jing, Arichanah Pulenthiran, Christopher D. Nevius, Abba Mejia-Spiegeler, Jonathan D. Suever, Gregory J. Wehner, H. Lester Kirchner, Christopher M. Haggerty, Brandon K. Fornwalt

Biomedical Engineering Faculty Publications

Background: Pediatric obesity is a growing public health problem, which is associated with increased risk of cardiovascular disease and premature death. Left ventricular (LV) remodeling (increased myocardial mass and thickness) and contractile dysfunction (impaired longitudinal strain) have been documented in obese children, but little attention has been paid to the right ventricle (RV). We hypothesized that obese/overweight children would have evidence of RV remodeling and contractile dysfunction.

Methods: One hundred and three children, ages 8–18 years, were prospectively recruited and underwent cardiovascular magnetic resonance (CMR), including both standard cine imaging and displacement encoding with stimulated echoes (DENSE) imaging, which allowed …

Shear Driven Micro-Fluidic Pump For Cardiovascular Applications, Nihad E. Daidzic

Aviation Department Publications

A valveless shear-driven micro-fluidic pump design (SDMFP) for hemodynamic applications is presented in this work. One of the possible medical and biomedical applications is in-vivo hemodynamic (human blood circulation) support/assist. One or more SDMFPs can be inserted/implanted into vascular lumens in a form of a stent/duct in series and/or in parallel (bypass duct) to support blood circulation in-vivo. A comprehensive review of various micro-pump designs up to about mid 2000’s is given in [1,2]. Many of micropump designs considered are not suitable for in-vivo or even in-vitro medical/biomedical applications.

Operating principles, design, and SDMFP features are given in [3]. A …

Using A Respiratory Navigator Significantly Reduces Variability When Quantifying Left Ventricular Torsion With Cardiovascular Magnetic Resonance, Sean M. Hamlet, Christopher M. Haggerty, Jonathan D. Suever, Gregory J. Wehner, Kristin N. Andres, David K. Powell, Richard J. Charnigo, Brandon K. Fornwalt

Electrical and Computer Engineering Faculty Publications

Background: Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic resonance (CMR) based quantification of LV torsion.

Methods: We assessed respiratory-related variability in measured LV torsion with two distinct experimental protocols. First, 17 volunteers were recruited for CMR with cine displacement encoding with stimulated echoes (DENSE) in which a respiratory navigator was used to measure …

Heart Pump Modelling: Design Of Pulsatile Flow Phantoms, Olivia Coiado, Kevin Jones, Parker Schibel, Nicolas De Almeida

Biomedical Engineering Western Regional Conference

The purpose of this project is to build a model, which mimics physiological conditions of the human cardiovascular system in order to simulate the parameters of the human heart in vivo. For this project, it was developed a flow phantom with vessel mimicking material, as well as blood-mimicking and tissue-mimicking fluid. Phantoms in general are specifically designed objects involving dedicated biomaterials to simulate special realistic circuits of human beings. To develop the flow phantom, low-priced biomaterials for blood mimicking fluid, tissue mimicking, and vessel mimicking material was researched.

Keywords: Cardiovascular system, heart pump, modelling, pulsatile.

Biventricular Finite Element Modeling And Quantification Of 3d Langragian Strains And Torsion Using Dense Mri, Zhanqiu Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

Statistical data suggests that increased use of evidence-based medical therapies has largely contributed to the decrease in American death rate caused by heart disease. And my studies are about two applications of magnetic resonance imaging (MRI) as a non-invasive approach in evidence-based health care research. In my first study, the achievement of a pulmonary valve replacement surgery was assessed on a patient with tetralogy of Fallot (TOF). In order to evaluate the remodeling of right ventricle, two biventricular finite element models were built up for pre-surgical images and post-surgical images. In my second study, 3D Lagrangian strains and torsion in …

An Algorithm For Extracting The Ppg Baseline Drift In Real-Time, Tuan Ngoc Nguyen

Theses: Doctorates and Masters

Photoplethysmography is an optical technique for measuring the perfusion of blood in skin and tissue arterial vessels. Due to its simplicity, accessibility and abundance of information on an individual’s cardiovascular system, it has been a pervasive topic of research within recent years. With these benefits however there are many challenges concerning the processing and conditioning of the signal in order to allow information to be extracted. One such challenge is removing the baseline drift of the signal, which is caused by respiratory rate, muscle tremor and physiological changes within the body as a response to various stimuli.

Over the years …

The Effect Of Neurostimulation On Ischemic Pain And Methods Of Assessing Pain, Kaylee Keck

Biomedical Engineering

Peripheral arterial disease (PAD) impacts approximately eight million people in the United States [1]. Disease progression leads to chronic ischemic pain, hindering quality of life. Pharmaceuticals are a typical treatment for pain associated with PAD; but as few as 30% of patients have a significant reduction of pain (≥50%) [2].

Neurostimulation is commonly used as a treatment for various diseases and injuries, including Parkinson’s disease and sports-related back and knee injuries [2]. The objective of the study was to explore neurostimulation and its effect on pain and paresthesia for a model of acute peripheral ischemia in young college students.

Pain …

Background Differences In Baseline And Stimulated Mmp Levels Influence Abdominal Aortic Aneurysm Susceptibility, Matthew A. Dale, Melissa K. Suh, Shijia Zhao, Trevor Meisinger, Linxia Gu, Vicki J. Swier, Devendra K. Agrawal, Timothy Greiner, Jeffrey S. Carson, B. Timothy Baxter, Wanfen Xiong

Department of Mechanical and Materials Engineering: Faculty Publications

Objective: Evidence has demonstrated profound influence of genetic background on cardiovascular phenotypes. Murine models in Marfan syndrome (MFS) have shown that genetic background-related variations affect thoracic aortic aneurysm formation, rupture, and lifespan of mice. MFS mice with C57Bl/6 genetic background are less susceptible to aneurysm formation compared to the 129/SvEv genetic background. In this study, we hypothesize that susceptibility to abdominal aortic aneurysm (AAA) will be increased in 129/SvEv mice versus C57Bl/6 mice. We tested this hypothesis by assessing differences in aneurysm size, tissue properties, immune response, and MMP expression.

Methods: Mice of C57Bl/6 or 129/SvEv background underwent AAA induction …

The Search For High-Impact Diagnostic And Management Tools For Low-And Middle-Income Countries: A Self-Powered Low-Cost Blood Pressure Measurement Device Powered By A Solid-State Vibration Energy Harvester, Onur Bilgen, John G. Kenerson, Muge Akpinar-Elci, Rebecca Hattery, Lisbet M. Hanson

Mechanical & Aerospace Engineering Faculty Publications

The World Health Organization has established recommendations for blood pressure measurement devices for use in low-resource venues, setting the triple A expectations of Accuracy, Affordability, and Availability. Because of issues related to training and assessment of proficiency, the pendulum has swung away from manual blood pressure devices and auscultatory techniques towards automatic oscillometric devices. As a result of power challenges in the developing world, there has also been a push towards semiautomatic devices that are not dependent on external power sources or batteries. Beyond solar solutions, disruptive technology related to solid-state vibrational energy harvesting may be the next iterative solution …

Bioengineered Hearts, Rivky Loeb

The Science Journal of the Lander College of Arts and Sciences

Heart disease is one of the highest causes for fatality in the world. Although many such diseases can be treated by a heart transplant, this in itself can cause countless problems. Aside from the high demand for donor hearts, there is the risk of the patient’s immune system rejecting the transplanted heart. A bioengineered heart would reduce the need for donor hearts, and thus save countless lives. Finding a suitable scaffold, obtaining appropriate cells, and ensuring that the tissue will function properly are the main focuses in creating an artificial heart. While most of the studies done have been concentrated …

Left Ventricular Assist Devices: Engineering Design Considerations, Marwan A. Simaan, Eduardo Divo, George Faragallah, Yu Wang

Publications

Patients with end-stage congestive heart failure awaiting heart transplantation often wait long periods of time (300 days or more on the average) before a suitable donor heart becomes available. The medical community has placed increased emphasis on the use of Left Ventricular Assist Devices or LVADs that can substitute for, or enhance, the function of the natural heart while the patient is waiting for the heart transplant (Poirier, 1997; Frazier & Myers, 1999). Essentially, a rotary LVAD is a pump that operates continuously directing blood from the left ventricle into the aorta by avoiding the aortic valve. Generally speaking, the …

Ischemia Impairs Vasodilation In Skeletal Muscle Resistance Artery, Kyle Remington Struthers

Master's Theses

Functional vasodilation in arterioles is impaired with chronic ischemia. We sought to examine the impact of chronic ischemia and age on skeletal muscle resistance artery function. To examine the impact of chronic ischemia, the femoral artery was resected from young (2-3mo) and adult (6-7mo) mice and the profunda femoris artery diameter was measured at rest and following gracilis muscle contraction 14 days later using intravital microscopy. Functional vasodilation was significantly impaired in ischemic mice (14.4±4.6% vs. 137.8±14.3%, p<0.0001 n=8) and non-ischemic adult mice (103.0±9.4% vs. 137.8±14.3%, p=0.05 n=10). In order to analyze the cellular mechanisms of the impairment, a protocol was developed to apply pharmacological agents to the experimental preparation while maintaining tissue homeostasis. Endothelial and smooth muscle dependent vasodilation were impaired with ischemia, 39.6 ± 13.6% vs. 80.5 ± 11.4% and 43.0 ± 11.7% vs. 85.1 ± 10.5%, respectively. From this data, it can be supported that smooth muscle dysfunction is the reason for the observed impairment in arterial vasodilation.

Generation Of Recombinant Mouse Embryonic Stem Cell Lines And Theirapplication For In Vivo Bioluminiscence Imaging In The Heart, Ramana Kammili

Electronic Theses and Dissertations

Cardiovascular disease is the major cause of death in the United States, with 80 million people suffering from some form of heart disease each year. One major limitation is the inability of the heart to repair the damaged tissue. Stem cell therapy holds enormous promise to repair and regenerate the damaged myocardium, but there are many technical difficulties that must first be overcome. One such difficulty is the present lack of ability to track and assess transplanted stem cells over time in vivo. The central hypothesis of this thesis is that in vivo bioluminescence imaging is a safe and useful …

Optimization Of Cryopreservation Protocols For Cardiovascular Tissue, Jianfei Hu

Theses and Dissertations in Biomedical Sciences

The purpose of this research was to determine the effects of cryopreservation on the physical, biochemical and cellular aspects of heart valve tissue. The present study demonstrated that radiolabeled proline accumulation provides a quantitative estimate of total cellular metabolic viability. Radiolabeled inulin was demonstrated to be a useful marker for extracellular tissue space. Assessment of metabolic viability of the cellular population of leaflet tissue as a function of procurement and processing revealed that proline accumulation declined with increasing warm and cold ischemic times. Amphotericin B and streptomycin were toxic to the cells. Cefoxitin, lincomycin, polymyxin B, vancomycin and penicillin had …