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Sample records for aortic input function

  1. Reproducibility of the aortic input function (AIF) derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of the kidneys in a volunteer study

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    Mendichovszky, I.A. [Radiology and Physics Unit, University College London, Institute of Child Health, 30 Guilford Street, London WC1N1EH (United Kingdom)], E-mail: i.mendichovszky@ich.ucl.ac.uk; Cutajar, M. [Radiology and Physics Unit, University College London, Institute of Child Health, 30 Guilford Street, London WC1N1EH (United Kingdom)], E-mail: m.cutajar@ich.ucl.ac.uk; Gordon, I. [Radiology and Physics Unit, University College London, Institute of Child Health, 30 Guilford Street, London WC1N1EH (United Kingdom)], E-mail: i.gordon@ich.ucl.ac.uk

    2009-09-15

    Purpose: The aim of this study was to investigate the maximum height, area under the curve (AUC) and full width at half maximum (FWHM) of the aortic input function (AIF) in renal dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) studies. We evaluated the significance of choice of size for regions of interest (ROI) in the aorta, reproducibility and inter-observer agreement of AIF measurements in healthy volunteers for renal DCE-MRI studies. Methods: Fifteen healthy volunteers (nine males, six females), mean age 28.8 years (range 23-36 years), underwent two DCE-MRI kidney studies under similar conditions. Oblique-coronal DCE-MRI data volumes were acquired on a 1.5 T Siemens Avanto scanner with a 3D-FLASH pulse-sequence (TE/TR = 0.53/1.63 ms, flip angle = 17 deg., acquisition matrix = 128 x 104 voxels, strong fat saturation, PAT factor = 2 (GRAPPA) and 400 mm x 325 mm FOV). Each dynamic dataset consisted of 18 slices of 7.5 mm thickness (no gap) and an in-plane resolution of 3.1 mm x 3.1 mm, acquired every 2.5 s for >5 min. During the MR scan a dose of 0.05 mmol (0.1 mL) kg{sup -1} body weight of dimeglumine gadopentetate (Magnevist) was injected intravenously (2 mL s{sup -1} injection rate), followed by a 15 mL saline flush at the same rate, using a MR-compatible automated injector (Spectris). For each DCE-MRI study two observers each drew two ROIs in the abdominal aorta. Both ROIs were 3 voxels in width and had the same inferior limit (just above the emergence of the renal arteries from the aorta) but had different heights (4 voxels for one ROI and 10 voxels for the other). The dimensions, position and time of drawing the ROIs in the dynamic study were standardised between observers prior to data analysis. Mean signal intensities measured in the ROIs were plotted over time, representing the AIF. For each study, AIF 1 was derived from ROI 1 and AIF 2 was derived from ROI 2. Results and conclusion: Paired t-tests for inter-observer comparison on the

  2. Computing Functions by Approximating the Input

    Science.gov (United States)

    Goldberg, Mayer

    2012-01-01

    In computing real-valued functions, it is ordinarily assumed that the input to the function is known, and it is the output that we need to approximate. In this work, we take the opposite approach: we show how to compute the values of some transcendental functions by approximating the input to these functions, and obtaining exact answers for their…

  3. Cellular regulation of the structure and function of aortic valves

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    Ismail El-Hamamsy

    2010-01-01

    Full Text Available The aortic valve was long considered a passive structure that opens and closes in response to changes in transvalvular pressure. Recent evidence suggests that the aortic valve performs highly sophisticated functions as a result of its unique microscopic structure. These functions allow it to adapt to its hemodynamic and mechanical environment. Understanding the cellular and molecular mechanisms involved in normal valve physiology is essential to elucidate the mechanisms behind valve disease. We here review the structure and developmental biology of aortic valves; we examine the role of its cellular parts in regulating its function and describe potential pathophysiological and clinical implications.

  4. Cytokine amplification and macrophage effector functions in aortic inflammation and abdominal aortic aneurysm formation.

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    Ijaz, Talha; Tilton, Ronald G; Brasier, Allan R

    2016-08-01

    On April 29, 2015, Son and colleagues published an article entitled "Granulocyte macrophage colony-stimulating factor (GM-CSF) is required for aortic dissection/intramural haematoma" in Nature Communications. The authors observed that the heterozygous Kruppel-like transcription factor 6 (KLF6) deficiency or absence of myeloid-specific KLF6 led to upregulation of macrophage GM-CSF expression, promoted the development of aortic hematoma/dissection, and stimulated abdominal aortic aneurysm (AAA) formation when the vessel wall was subjected to an inflammatory stimulus. The additional findings of increased adventitial fibrotic deposition, marked infiltration of macrophages, and increased expression of matrix metalloprotease-9 (MMP-9) and IL-6 were blocked with neutralizing GM-CSF antibodies, or recapitulated in normal mice with excess GM-CSF administration. The authors concluded that GM-CSF is a key regulatory molecule in the development of AAA and further suggested that activation of GM-CSF is independent of the transforming growth factor β (TGFβ)-Smad pathway associated with the Marfan aortic pathology. In this perspective, we expand on this mechanism, drawing from previous studies implicating a similar essential role for IL-6 signaling in macrophage activation, Th17 expansion and aortic dissections. We propose a sequential "two-hit" model of vascular inflammation involving initial vascular injury followed by recruitment of Ly6C(hi) macrophages. Aided by fibroblast interactions inflammatory macrophages produce amplification of IL-6 and GM-CSF expression that converge on a common, pathogenic Janus kinase (JAK)-signal transducers and activations of transcription 3 (STAT3) signaling pathway. This pathway stimulates effector functions of macrophages, promotes differentiation of Th17 lymphocytes and enhances matrix metalloproteinase expression, ultimately resulting in deterioration of vascular wall structural integrity. Further research evaluating the impact of

  5. Aortic Blood Flow Reversal Determines Renal Function: Potential Explanation for Renal Dysfunction Caused by Aortic Stiffening in Hypertension.

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    Hashimoto, Junichiro; Ito, Sadayoshi

    2015-07-01

    Aortic stiffness determines the glomerular filtration rate (GFR) and predicts the progressive decline of the GFR. However, the underlying pathophysiological mechanism remains obscure. Recent evidence has shown a close link between aortic stiffness and the bidirectional (systolic forward and early diastolic reverse) flow characteristics. We hypothesized that the aortic stiffening-induced renal dysfunction is attributable to altered central flow dynamics. In 222 patients with hypertension, Doppler velocity waveforms were recorded at the proximal descending aorta to calculate the reverse/forward flow ratio. Tonometric waveforms were recorded to measure the carotid-femoral (aortic) and carotid-radial (peripheral) pulse wave velocities, to estimate the aortic pressure from the radial waveforms, and to compute the aortic characteristic impedance. In addition, renal hemodynamics was evaluated by duplex ultrasound. The estimated GFR was inversely correlated with the aortic pulse wave velocity, reverse/forward flow ratio, pulse pressure, and characteristic impedance, whereas it was not correlated with the peripheral pulse wave velocity or mean arterial pressure. The association between aortic pulse wave velocity and estimated GFR was independent of age, diabetes mellitus, hypercholesterolemia, and antihypertensive medication. However, further adjustment for the aortic reverse/forward flow ratio and pulse pressure substantially weakened this association, and instead, the reverse/forward flow ratio emerged as the strongest determinant of estimated GFR (P=0.001). A higher aortic reverse/forward flow ratio was also associated with lower intrarenal forward flow velocities. These results suggest that an increase in aortic flow reversal (ie, retrograde flow from the descending thoracic aorta toward the aortic arch), caused by aortic stiffening and impedance mismatch, reduces antegrade flow into the kidney and thereby deteriorates renal function.

  6. Significance of input correlations in striatal function.

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    Man Yi Yim

    2011-11-01

    Full Text Available The striatum is the main input station of the basal ganglia and is strongly associated with motor and cognitive functions. Anatomical evidence suggests that individual striatal neurons are unlikely to share their inputs from the cortex. Using a biologically realistic large-scale network model of striatum and cortico-striatal projections, we provide a functional interpretation of the special anatomical structure of these projections. Specifically, we show that weak pairwise correlation within the pool of inputs to individual striatal neurons enhances the saliency of signal representation in the striatum. By contrast, correlations among the input pools of different striatal neurons render the signal representation less distinct from background activity. We suggest that for the network architecture of the striatum, there is a preferred cortico-striatal input configuration for optimal signal representation. It is further enhanced by the low-rate asynchronous background activity in striatum, supported by the balance between feedforward and feedback inhibitions in the striatal network. Thus, an appropriate combination of rates and correlations in the striatal input sets the stage for action selection presumably implemented in the basal ganglia.

  7. Integrating agronomic principles into production function estimation: A dichotomy of growth inputs and facilitating inputs

    NARCIS (Netherlands)

    Zhengfei, G.; Oude Lansink, A.G.J.M.; Ittersum, van M.K.; Wossink, G.A.A.

    2006-01-01

    This article presents a general conceptual framework for integrating agronomic principles into economic production analysis. We categorize inputs in crop production into growth inputs and facilitating inputs. Based on this dichotomy we specify an asymmetric production function. The robustness of the

  8. Are Financial Variables Inputs in Delivered Production Functions? Are Financial Variables Inputs in Delivered Production Functions?

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    Miguel Kiguel

    1995-03-01

    Full Text Available Fischer's classic (1974 paper develops conditions under which it is appropriate to use money as an input in a 'delivered' production function. In this paper, we extend Fischer's model I (the Baumol-Tobin inventory approach by incorporating credit into the analysis. Our investigation of the extended model brings out a very restrictive but necessary implicit assumption employed by Fischer to treat money as an input. Namely. that there exists a binding constraint on the use of money! A similar result holds for our more general model. Fischer's classic (1974 paper develops conditions under which it is appropriate to use money as an input in a 'delivered' production function. In this paper, we extend Fischer's model I (the Baumol-Tobin inventory approach by incorporating credit into the analysis. Our investigation of the extended model brings out a very restrictive but necessary implicit assumption employed by Fischer to treat money as an input. Namely. that there exists a binding constraint on the use of money! A similar result holds for our more general model.

  9. Systemic levels of cotinine and elastase, but not pulmonary function, are associated with the progression of small abdominal aortic aneurysms

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    Lindholt, Jes Sanddal; Jørgensen, B; Klitgaard, N A;

    2003-01-01

    to study whether smoking and impaired pulmonary function are associated with the expansion of abdominal aortic aneurysms (AAA).......to study whether smoking and impaired pulmonary function are associated with the expansion of abdominal aortic aneurysms (AAA)....

  10. Acute regional improvement of myocardial function after interventional transfemoral aortic valve replacement in aortic stenosis: A speckle tracking echocardiography study

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    Schattke Sebastian

    2012-03-01

    Full Text Available Abstract Background Transcatheter aortic valve implantation (TAVI is a promising therapy for patients with severe aortic stenosis (AS and high perioperative risk. New echocardiographic methods, including 2D Strain analysis, allow the more accurate measurement of left ventricular (LV systolic function. The goal of this study was to describe the course of LV reverse remodelling immediately after TAVI in a broad spectrum of patients with symptomatic severe aortic valve stenosis. Methods Thirty consecutive patients with symptomatic aortic valve stenosis and preserved LVEF underwent transfemoral aortic valve implantation. We performed echocardiography at baseline and one week after TAVI. Echocardiography included standard 2D and Doppler analysis of global systolic and diastolic function as well as 2D Strain measurements of longitudinal, radial and circumferential LV motion and Tissue Doppler echocardiography. Results The baseline biplane LVEF was 57 ± 8.2%, the mean pressure gradient was 46.8 ± 17.2 mmHg and the mean valve area was 0.73 ± 0.27 cm2. The average global longitudinal 2D strain of the left ventricle improved significantly from -15.1 (± 3.0 to -17.5 (± 2.4 % (p Conclusion There is an acute improvement of myocardial longitudinal systolic function of the basal and medial segments measured by 2D Strain analysis immediately after TAVI. The radial, circumferential strain and LVEF does not change significantly in all patients acutely after TAVI. These data suggest that sensitive new echo methods can reliably detect early regional changes of myocardial function after TAVI before benefits in LVEF are detectable.

  11. Memoization technique for optimizing functions with stochastic input

    OpenAIRE

    Mulalić, Edin H.; Stanković, Miomir S.; Radomir S. Stanković

    2012-01-01

    In this paper we present a strategy for optimization functions with stochastic input. The main idea is to take advantage of decomposition in combination with a look-up table. Deciding what input values should be used for memoization is determined based on the underlying probability distribution of input variables. Special attention is given to difficulties caused by combinatorial explosion.

  12. Dynamic heart phantom with functional mitral and aortic valves

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    Vannelli, Claire; Moore, John; McLeod, Jonathan; Ceh, Dennis; Peters, Terry

    2015-03-01

    Cardiac valvular stenosis, prolapse and regurgitation are increasingly common conditions, particularly in an elderly population with limited potential for on-pump cardiac surgery. NeoChord©, MitraClipand numerous stent-based transcatheter aortic valve implantation (TAVI) devices provide an alternative to intrusive cardiac operations; performed while the heart is beating, these procedures require surgeons and cardiologists to learn new image-guidance based techniques. Developing these visual aids and protocols is a challenging task that benefits from sophisticated simulators. Existing models lack features needed to simulate off-pump valvular procedures: functional, dynamic valves, apical and vascular access, and user flexibility for different activation patterns such as variable heart rates and rapid pacing. We present a left ventricle phantom with these characteristics. The phantom can be used to simulate valvular repair and replacement procedures with magnetic tracking, augmented reality, fluoroscopy and ultrasound guidance. This tool serves as a platform to develop image-guidance and image processing techniques required for a range of minimally invasive cardiac interventions. The phantom mimics in vivo mitral and aortic valve motion, permitting realistic ultrasound images of these components to be acquired. It also has a physiological realistic left ventricular ejection fraction of 50%. Given its realistic imaging properties and non-biodegradable composition—silicone for tissue, water for blood—the system promises to reduce the number of animal trials required to develop image guidance applications for valvular repair and replacement. The phantom has been used in validation studies for both TAVI image-guidance techniques1, and image-based mitral valve tracking algorithms2.

  13. Simulation study and function analysis of the dynamic aortic valve

    Institute of Scientific and Technical Information of China (English)

    XIA Dongdong; BAI Jing

    2006-01-01

    The dynamic aortic valve (DAV) is a new left ventricular assist device, a micro-axial blood pump implemented at the position of the aortic valve, pumping blood from the left ventricle into the aortic artery. The present dynamic aortic valve operates at 7 different rotation speeds, ranging from 3000 r/min (speed 1) to 9000 r/min (speed 7). Because in vivo experiments need a lot of live animals and take a long period of time, modeling and simulation have been widely used to simulate and analyze hydra-dynamic property of the DAV and its assisting effects. With the measurements from the mock circulatory loop, a mathematic model of the DAV is established and embedded into the previously developed canine circulatory system. Using this model, the effect of the DAV on the failing heart at each rotation speed level is investigated. The vital cardiac variables are computed and compared with in vivo experimental results, which are in good agreement with an acceptable difference mostly 15 %. The establishment of the DAV model and its simulation are useful for further improvement of the DAV device.

  14. [Heart valves after 22 years - good long-term function of aortic homograft, advanced impairment in function of atrioventricular valves].

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    Michalski, Błazej; Chrzanowski, Lukasz; Krzemińska-Pakula, Maria; Kasprzak, Jarosław D

    2010-03-01

    We report a case of a 61-year-old female patient with a history of aortic valve replacement, who was admitted to our hospital with symptoms and signs of decompensated heart failure (NYHA class III). Transthoracic echocardiogram revealed mitral valve and tricuspid valve regurgitation (III grade) with normal function of aortic valve homograft implanted 22 years ago. The patient underwent cardiosurgical mitral valve replacement and tricuspid valve annuloplasty with very good result. An aortic valve homograft may be the best alternative to a mechanical valves for a young female patients. PMID:20411462

  15. Low-flow aortic stenosis in asymptomatic patients: valvular-arterial impedance and systolic function from the SEAS Substudy

    DEFF Research Database (Denmark)

    Cramariuc, Dana; Cioffi, Giovanni; Rieck, Ashild E;

    2009-01-01

    OBJECTIVES: This study sought to assess the impact of valvuloarterial impedance on left ventricular (LV) myocardial systolic function in asymptomatic aortic valve stenosis (AS). BACKGROUND: In atherosclerotic AS, LV global load consists of combined valvular and arterial resistance to LV ejection....... preserved. (An Investigational Drug on Clinical Outcomes in Patients With Aortic Stenosis [Narrowing of the Major Blood Vessel of the Heart]; NCT00092677)....

  16. Quantitative amyloid imaging using image-derived arterial input function.

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    Yi Su

    Full Text Available Amyloid PET imaging is an indispensable tool widely used in the investigation, diagnosis and monitoring of Alzheimer's disease (AD. Currently, a reference region based approach is used as the mainstream quantification technique for amyloid imaging. This approach assumes the reference region is amyloid free and has the same tracer influx and washout kinetics as the regions of interest. However, this assumption may not always be valid. The goal of this work is to evaluate an amyloid imaging quantification technique that uses arterial region of interest as the reference to avoid potential bias caused by specific binding in the reference region. 21 participants, age 58 and up, underwent Pittsburgh compound B (PiB PET imaging and MR imaging including a time-of-flight (TOF MR angiography (MRA scan and a structural scan. FreeSurfer based regional analysis was performed to quantify PiB PET data. Arterial input function was estimated based on coregistered TOF MRA using a modeling based technique. Regional distribution volume (VT was calculated using Logan graphical analysis with estimated arterial input function. Kinetic modeling was also performed using the estimated arterial input function as a way to evaluate PiB binding (DVRkinetic without a reference region. As a comparison, Logan graphical analysis was also performed with cerebellar cortex as reference to obtain DVRREF. Excellent agreement was observed between the two distribution volume ratio measurements (r>0.89, ICC>0.80. The estimated cerebellum VT was in line with literature reported values and the variability of cerebellum VT in the control group was comparable to reported variability using arterial sampling data. This study suggests that image-based arterial input function is a viable approach to quantify amyloid imaging data, without the need of arterial sampling or a reference region. This technique can be a valuable tool for amyloid imaging, particularly in population where reference

  17. Relationships between retinal arteriole anatomy and aortic geometry and function and peripheral resistance in hypertensives.

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    Rosenbaum, David; Kachenoura, Nadjia; Koch, Edouard; Paques, Michel; Cluzel, Philippe; Redheuil, Alban; Girerd, Xavier

    2016-07-01

    Microvascular remodeling and large artery stiffness are key determinants of cardiovascular hemodynamics and can now be studied with new non-invasive methods. Our objective was to study the relationships between retinal arteriole anatomy and aortic geometry and function and peripheral resistance (total peripheral resistance (TPR)) in hypertensives. In 80 subjects (age 52±13 years; 53% males; including 23 normotensives and 57 hypertensives, among which 29 were uncontrolled hypertensives), we used: (1) the new non-invasive RTX1 adaptive optics (AO) camera (Imagine Eyes, Orsay, France) to measure the wall-to-lumen ratio (WLR) on retinal microvasculature; (2) cardiovascular magnetic resonance (CMR) imaging to assess aortic stiffness, geometry and cardiac output; and (3) the validated SphymoCor Xcel device to measure central blood pressure (BP) and carotido-femoral pulse wave velocity (Cf-PWV). TPR was calculated as the central mean BP/cardiac output ratio. WLR and TPR were significantly higher and aortic distensibility was significantly lower in hypertensives. Aortic dilation and arch elongation were found in uncontrolled hypertensives. In the univariate analysis, WLR was positively correlated with central BP (PTPR (PTPR (P=0.002) independent of age, BMI, gender, antihypertensive treatments, aortic diameter and central SBP. As expected, age was the major correlate of ascending aorta distensibility and Cf-PWV. New non-invasive vascular imaging methods are complementary for the detection of the deleterious effects of aging or high BP on large and small arteries. AO examination could represent a useful tool for the study and follow-up of microvasculature anatomical changes.

  18. Mechanism of aortic root dilation and cardiovascular function in tetralogy of Fallot.

    Science.gov (United States)

    Seki, Mitsuru; Kuwata, Seiko; Kurishima, Clara; Nakagawa, Ryo; Inuzuka, Ryo; Sugimoto, Masaya; Saiki, Hirofumi; Iwamoto, Yoichi; Ishido, Hirotaka; Masutani, Satoshi; Senzaki, Hideaki

    2016-05-01

    The aortic root dilation in tetralogy of Fallot (TOF) is a long-term clinical problem, because a severely dilated aorta can lead to aortic regurgitation, dissection, or rupture, which can be fatal, necessitating surgical intervention. The details of the mechanism of aortic root dilation, however, are unclear. We have shown that aortic stiffness is increased in patients with repaired TOF, and may mirror the histological abnormality of elastic fiber disruption and matrix expansion. This aortic stiffness is related closely to the aortic dilation, indicating that aortic stiffness may be a predictor of outcome of aortic dilation. Furthermore, the aortic volume overload is a very important determinant of aortic diameter in TOF patients before corrective surgery. In addition, a chromosomal abnormality and the transforming growth factor-β signaling pathway, a major contributor to aortic dilation in Marfan syndrome, also affect this mechanism. In this way, aortic dilation in TOF patients is suggested to be a multifactorial disorder. The aim of this review was therefore to clarify the mechanism of aortic dilation in TOF, focusing on recent research findings. Studies linking histopathology, mechanical properties, molecular/cellular physiology, and clinical manifestations of aortic dilation facilitate appropriate treatment intervention and improvement of long-term prognosis of TOF. PMID:26809655

  19. Visual display panel functions as computer input/output device

    Science.gov (United States)

    Hilborn, E. H.

    1970-01-01

    Display panel permits information entry and erasure using a probe, and has an inherent storage capability for use on time-shared systems. Data input need not be online. Other advantages include direct display of input and output, simplicity, and low fabrication cost.

  20. Mitochondrial oxidative stress in aortic stiffening with age: the role of smooth muscle cell function.

    Science.gov (United States)

    OBJECTIVE: Age-related aortic stiffness is an independent risk factor for cardiovascular diseases. Although oxidative stress is implicated in aortic stiffness, the underlying molecular mechanisms remain unelucidated. Here, we examined the source of oxidative stress in aging and i...

  1. An adaptive transfer function for deriving the aortic pressure waveform from a peripheral artery pressure waveform.

    Science.gov (United States)

    Swamy, Gokul; Xu, Da; Olivier, N Bari; Mukkamala, Ramakrishna

    2009-11-01

    We developed a new technique to mathematically transform a peripheral artery pressure (PAP) waveform distorted by wave reflections into the physiologically more relevant aortic pressure (AP) waveform. First, a transfer function relating PAP to AP is defined in terms of the unknown parameters of a parallel tube model of pressure and flow in the arterial tree. The parameters are then estimated from the measured PAP waveform along with a one-time measurement of the wave propagation delay time between the aorta and peripheral artery measurement site (which may be accomplished noninvasively) by exploiting preknowledge of aortic flow. Finally, the transfer function with its estimated parameters is applied to the measured waveform so as to derive the AP waveform. Thus, in contrast to the conventional generalized transfer function, the transfer function is able to adapt to the intersubject and temporal variability of the arterial tree. To demonstrate the feasibility of this adaptive transfer function technique, we performed experiments in 6 healthy dogs in which PAP and reference AP waveforms were simultaneously recorded during 12 different hemodynamic interventions. The AP waveforms derived by the technique showed agreement with the measured AP waveforms (overall total waveform, systolic pressure, and pulse pressure root mean square errors of 3.7, 4.3, and 3.4 mmHg, respectively) statistically superior to the unprocessed PAP waveforms (corresponding errors of 8.6, 17.1, and 20.3 mmHg) and the AP waveforms derived by two previously proposed transfer functions developed with a subset of the same canine data (corresponding errors of, on average, 5.0, 6.3, and 6.7 mmHg). PMID:19783780

  2. Functional Heart Valve Scaffolds Obtained by Complete Decellularization of Porcine Aortic Roots in a Novel Differential Pressure Gradient Perfusion System.

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    Sierad, Leslie Neil; Shaw, Eliza Laine; Bina, Alexander; Brazile, Bryn; Rierson, Nicholas; Patnaik, Sourav S; Kennamer, Allison; Odum, Rebekah; Cotoi, Ovidiu; Terezia, Preda; Branzaniuc, Klara; Smallwood, Harrison; Deac, Radu; Egyed, Imre; Pavai, Zoltan; Szanto, Annamaria; Harceaga, Lucian; Suciu, Horatiu; Raicea, Victor; Olah, Peter; Simionescu, Agneta; Liao, Jun; Movileanu, Ionela; Harpa, Marius; Simionescu, Dan Teodor

    2015-12-01

    There is a great need for living valve replacements for patients of all ages. Such constructs could be built by tissue engineering, with perspective of the unique structure and biology of the aortic root. The aortic valve root is composed of several different tissues, and careful structural and functional consideration has to be given to each segment and component. Previous work has shown that immersion techniques are inadequate for whole-root decellularization, with the aortic wall segment being particularly resistant to decellularization. The aim of this study was to develop a differential pressure gradient perfusion system capable of being rigorous enough to decellularize the aortic root wall while gentle enough to preserve the integrity of the cusps. Fresh porcine aortic roots have been subjected to various regimens of perfusion decellularization using detergents and enzymes and results compared to immersion decellularized roots. Success criteria for evaluation of each root segment (cusp, muscle, sinus, wall) for decellularization completeness, tissue integrity, and valve functionality were defined using complementary methods of cell analysis (histology with nuclear and matrix stains and DNA analysis), biomechanics (biaxial and bending tests), and physiologic heart valve bioreactor testing (with advanced image analysis of open-close cycles and geometric orifice area measurement). Fully acellular porcine roots treated with the optimized method exhibited preserved macroscopic structures and microscopic matrix components, which translated into conserved anisotropic mechanical properties, including bending and excellent valve functionality when tested in aortic flow and pressure conditions. This study highlighted the importance of (1) adapting decellularization methods to specific target tissues, (2) combining several methods of cell analysis compared to relying solely on histology, (3) developing relevant valve-specific mechanical tests, and (4) in vitro testing

  3. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

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    Elderen, Saskia G.C. van; Brandts, A.; Westenberg, J.J.M.; Grond, J. van der; Buchem, M.A. van; Kroft, L.J.M.; Roos, A. de [Leiden University Medical Center, Department of Radiology, Leiden (Netherlands); Tamsma, J.T.; Romijn, J.A.; Smit, J.W.A. [Leiden University Medical Center, Department of Endocrinology, Leiden (Netherlands)

    2010-05-15

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 {+-} 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 {+-} 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  4. Aortic stiffness is associated with cardiac function and cerebral small vessel disease in patients with type 1 diabetes mellitus: assessment by magnetic resonance imaging

    International Nuclear Information System (INIS)

    To evaluate, with the use of magnetic resonance imaging (MRI), whether aortic pulse wave velocity (PWV) is associated with cardiac left ventricular (LV) function and mass as well as with cerebral small vessel disease in patients with type 1 diabetes mellitus (DM). We included 86 consecutive type 1 DM patients (49 male, mean age 46.9 ± 11.7 years) in a prospective, cross-sectional study. Exclusion criteria included aortic/heart disease and general MRI contra-indications. MRI of the aorta, heart and brain was performed for assessment of aortic PWV, as a marker of aortic stiffness, systolic LV function and mass, as well as for the presence of cerebral white matter hyperintensities (WMHs), microbleeds and lacunar infarcts. Multivariate linear or logistic regression was performed to analyse the association between aortic PWV and outcome parameters, with covariates defined as age, gender, mean arterial pressure, heart rate, BMI, smoking, DM duration and hypertension. Mean aortic PWV was 7.1 ± 2.5 m/s. Aortic PWV was independently associated with LV ejection fraction (ss= -0.406, P = 0.006), LV stroke volume (ss=-0.407, P = 0.001), LV cardiac output (ss= -0.458, P = 0.001), and with cerebral WMHs (P < 0.05). There were no independent associations between aortic stiffness and LV mass, cerebral microbleeds or lacunar infarcts. Aortic stiffness is independently associated with systolic LV function and cerebral WMHs in patients with type 1 DM. (orig.)

  5. Plasticity of the cis-regulatory input function of a gene.

    Directory of Open Access Journals (Sweden)

    Avraham E Mayo

    2006-04-01

    Full Text Available The transcription rate of a gene is often controlled by several regulators that bind specific sites in the gene's cis-regulatory region. The combined effect of these regulators is described by a cis-regulatory input function. What determines the form of an input function, and how variable is it with respect to mutations? To address this, we employ the well-characterized lac operon of Escherichia coli, which has an elaborate input function, intermediate between Boolean AND-gate and OR-gate logic. We mapped in detail the input function of 12 variants of the lac promoter, each with different point mutations in the regulator binding sites, by means of accurate expression measurements from living cells. We find that even a few mutations can significantly change the input function, resulting in functions that resemble Pure AND gates, OR gates, or single-input switches. Other types of gates were not found. The variant input functions can be described in a unified manner by a mathematical model. The model also lets us predict which functions cannot be reached by point mutations. The input function that we studied thus appears to be plastic, in the sense that many of the mutations do not ruin the regulation completely but rather result in new ways to integrate the inputs.

  6. Aortic insufficiency

    Science.gov (United States)

    ... Heart valve - aortic regurgitation; Valvular disease - aortic regurgitation; AI - aortic insufficiency ... BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: ...

  7. Left ventricular diastolic function is associated with symptom status in severe aortic valve stenosis

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Christensen, Nicolaj L; Videbæk, Lars;

    2014-01-01

    BACKGROUND: In aortic valve stenosis (AS), the occurrence of heart failure symptoms does not always correlate with severity of valve stenosis and left ventricular (LV) function. Therefore, we tested the hypothesis that symptomatic patients with AS have impaired diastolic, longitudinal systolic......%. Independent predictors of symptomatic state were identified using logistic regression analysis. Symptomatic patients were younger (72±10 versus 76±12 years of age; P=0.002), presented less often with atrial fibrillation (13% versus 24%; P=0.05) and chronic obstructive pulmonary disease (2% versus 19%; P<0......±58 versus 268±62 ms; P<0.0001), and increased left atrial volume index (49±18 versus 42±15 mL/m2; P=0.02). When adjusting for age, history of hypertension, atrial fibrillation, and chronic obstructive pulmonary disease in a multivariable logistic regression analysis, LV mass index, relative wall thickness...

  8. A General Input Distance Function Based on Opportunity Costs

    Directory of Open Access Journals (Sweden)

    Juan Aparicio

    2011-01-01

    Full Text Available There are several distance function definitions in a general production framework, including Data Envelopment Analysis, which can be used to describe the production technology and to define corresponding measures of technical efficiency (notably the Shephard and the directional distance functions. This paper introduces a generalisation of the distance function concept based on the idea of minimizing firm's opportunity cost. We further state a general dual correspondence between the cost function and this new general distance function, which encompasses all previously published duality results. All our results also hold under the assumption that we work in a Data Envelopment Analysis context.

  9. Clinical, radiological and functional follow-up after surgical decompression of double aortic arch

    Energy Technology Data Exchange (ETDEWEB)

    Berge, Maartje ten; Laag, Johan van der; Ent, Cornelis K. van der [Department of Respiratory Diseases, Wilhelmina Children' s Hospital, Utrecht (Netherlands); Beek, Frederik J.A. [Department of Radiology, Wilhelmina Children' s Hospital, Lundlaan 6, 3584 EA Utrecht (Netherlands)

    2002-08-01

    Heading AbstractBackground. Double aortic arch (DAA) is a congenital vascular anomaly that causes tracheal and oesophageal compression. It requires surgical intervention in patients with severe symptoms.Objective. To evaluate the clinical, radiological and functional follow-up after surgical relief of the compression.Materials and methods. Ten children (seven boys) with DAA were operated on at a mean age of 1.3 years (range 0.2-7.5). At a mean age of 10.1 years (range 5-18 years), a follow-up study was performed that included clinical, radiological and functional parameters.Results. Seven children reported only mild respiratory symptoms and some trouble with swallowing. Preoperative fluoroscopy with spot images showed the mean tracheal diameter at the level of stenosis to be 37{+-}23% of the maximal diameter. At the time of follow-up, this was 70{+-}13%. The mean of the oesophageal diameter was 39{+-}20% preoperatively and 47{+-}16% postoperatively. Maximal expiratory flow volume (MEFV) curves of seven children showed typical characteristics of intrathoracic upper airway obstruction. Mean peak expiratory flow was significantly reduced (77{+-}10% of predicted, P<0.0001). Bronchial hyper-reactivity, tested by methacholine challenge, was found in two patients.Conclusions. There was marked relief of clinical symptoms after surgical decompression of DAA in all patients. In spite of this, radiological narrowing of trachea and oesophagus persisted and lung function results were abnormal at long-term follow-up. (orig.)

  10. SOD1 Overexpression Preserves Baroreflex Control of Heart Rate with an Increase of Aortic Depressor Nerve Function.

    Science.gov (United States)

    Hatcher, Jeffrey; Gu, He; Cheng, Zixi Jack

    2016-01-01

    Overproduction of reactive oxygen species (ROS), such as the superoxide radical (O2 (∙-)), is associated with diseases which compromise cardiac autonomic function. Overexpression of SOD1 may offer protection against ROS damage to the cardiac autonomic nervous system, but reductions of O2 (∙-) may interfere with normal cellular functions. We have selected the C57B6SJL-Tg (SOD1)2 Gur/J mouse as a model to determine whether SOD1 overexpression alters cardiac autonomic function, as measured by baroreflex sensitivity (BRS) and aortic depressor nerve (ADN) recordings, as well as evaluation of baseline heart rate (HR) and mean arterial pressure (MAP). Under isoflurane anesthesia, C57 wild-type and SOD1 mice were catheterized with an arterial pressure transducer and measurements of HR and MAP were taken. After establishing a baseline, hypotension and hypertension were induced by injection of sodium nitroprusside (SNP) and phenylephrine (PE), respectively, and ΔHR versus ΔMAP were recorded as a measure of baroreflex sensitivity (BRS). SNP and PE treatment were administered sequentially after a recovery period to measure arterial baroreceptor activation by recording aortic depressor nerve activity. Our findings show that overexpression of SOD1 in C57B6SJL-Tg (SOD1)2 Gur/J mouse preserved the normal HR, MAP, and BRS but enhanced aortic depressor nerve function. PMID:26823951

  11. SOD1 Overexpression Preserves Baroreflex Control of Heart Rate with an Increase of Aortic Depressor Nerve Function

    Science.gov (United States)

    Hatcher, Jeffrey; Gu, He; Cheng, Zixi (Jack)

    2016-01-01

    Overproduction of reactive oxygen species (ROS), such as the superoxide radical (O2∙−), is associated with diseases which compromise cardiac autonomic function. Overexpression of SOD1 may offer protection against ROS damage to the cardiac autonomic nervous system, but reductions of O2∙− may interfere with normal cellular functions. We have selected the C57B6SJL-Tg (SOD1)2 Gur/J mouse as a model to determine whether SOD1 overexpression alters cardiac autonomic function, as measured by baroreflex sensitivity (BRS) and aortic depressor nerve (ADN) recordings, as well as evaluation of baseline heart rate (HR) and mean arterial pressure (MAP). Under isoflurane anesthesia, C57 wild-type and SOD1 mice were catheterized with an arterial pressure transducer and measurements of HR and MAP were taken. After establishing a baseline, hypotension and hypertension were induced by injection of sodium nitroprusside (SNP) and phenylephrine (PE), respectively, and ΔHR versus ΔMAP were recorded as a measure of baroreflex sensitivity (BRS). SNP and PE treatment were administered sequentially after a recovery period to measure arterial baroreceptor activation by recording aortic depressor nerve activity. Our findings show that overexpression of SOD1 in C57B6SJL-Tg (SOD1)2 Gur/J mouse preserved the normal HR, MAP, and BRS but enhanced aortic depressor nerve function. PMID:26823951

  12. Effects of preemptive enoximone on left ventricular diastolic function after valve replacement for aortic stenosis

    NARCIS (Netherlands)

    van der Maaten, Joost M. A. A.; de Vries, Adrianus J.; Rietman, Gerrit W.; Gallandat Huet, Rolf C. G.; De Hert, Stefan G.

    2007-01-01

    Objective: Left ventricular (LV) hypertrophy is associated with increased diastolic chamber stiffness early after aortic valve replacement for valve stenosis. Enoximone, a phosphodiesterase III inhibitor, has been shown to improve myocardial contractility and relaxation when administered as a single

  13. Measuring Scale Efficiency from the Translog Multi-Input, Multi-Output Distance Function

    OpenAIRE

    Subhash Ray

    2003-01-01

    Ray (1998) developed measures of input- and output-oriented scale efficiency that can be directly computed from an estimated Translog frontier production function. This note extends the earlier results from Ray (1998) to the multiple-output multiple input case.

  14. The Impact of Endovascular Repair of Ruptured Abdominal Aortic Aneurysm on the Gastrointestinal and Renal Function

    Directory of Open Access Journals (Sweden)

    R. R. Makar

    2014-01-01

    Full Text Available Introduction. Systemic effects of ruptured abdominal aortic aneurysm (rAAA may be altered by the mode of surgery. This study aimed to determine systemic effects of endovascular aneurysm repair (EVAR compared to open repair (OR. Patients and Methods. Consecutive patients with rAAA were repaired by OR or EVAR according to computerised tomographic (CT findings. Renal function was monitored by estimated glomerular filtration rate (eGFR, serum urea and creatinine, and urinary albumin creatinine ratio (ACR. Hepatic function was assessed postoperatively for 5 days. Intestinal function was determined by the paracetamol absorption test. Intestinal permeability was assessed by urinary lactulose/mannitol ratio. Results. 30 rAAA patients were included. Fourteen had eEVAR and sixteen eOR. Serum urea were higher in eOR, while creatinine was similar between groups. Hepatic function showed no intergroup difference. Paracetamol absorption was increased in eEVAR group at day 3 compared to day 1 (P=0.03, with no similar result in eOR (P=0.24. Peak lactulose/mannitol ratio was higher in eOR (P=0.03, with higher urinary L/M ratio in eOR at day 3 (P=0.02. Clinical intestinal function returned quicker in eEVAR (P=0.02. Conclusion. EVAR attenuated the organ dysfunction compared to open repair. However, a larger comparative trial would be required to validate this. The clinical trial is registered with reference number EUDRACT: 2013-003373-12.

  15. Expression of a functional extracellular calcium-sensing receptor in human aortic endothelial cells

    International Nuclear Information System (INIS)

    Extracellular Ca2+ concentration ([Ca2+]o) regulates the functions of many cell types through a G protein-coupled [Ca2+]o-sensing receptor (CaR). Whether the receptor is functionally expressed in vascular endothelial cells is largely unknown. In cultured human aortic endothelial cells (HAEC), RT-PCR yielded the expected 555-bp product corresponding to the CaR, and CaR protein was demonstrated by fluorescence immunostaining and Western blot. RT-PCR also demonstrated the expression in HAEC of alternatively spliced variants of the CaR lacking exon 5. Although stimulation of fura 2-loaded HAEC by several CaR agonists (high [Ca2+]o, neomycin, and gadolinium) failed to increase intracellular Ca2+ concentration ([Ca2+]i), the CaR agonist spermine stimulated an increase in [Ca2+]i that was diminished in buffer without Ca2+ and was abolished after depletion of an intracellular Ca2+ pool with thapsigargin or after blocking IP3- and ryanodine receptor-mediated Ca2+ release with xestospongin C and with high concentration ryanodine, respectively. Spermine stimulated an increase in DAF-FM fluorescence in HAEC, consistent with NO production. Both the increase in [Ca2+]i and in NO production were reduced or absent in HAEC transfected with siRNA specifically targeted to the CaR. HAEC express a functional CaR that responds to the endogenous polyamine spermine with an increase in [Ca2+]i, primarily due to release of IP3- and ryanodine-sensitive intracellular Ca2+ stores, leading to the production of NO. Expression of alternatively spliced variants of the CaR may result in the absence of a functional response to other known CaR agonists in HAEC

  16. Loss of function mutation in LOX causes thoracic aortic aneurysm and dissection in humans.

    Science.gov (United States)

    Lee, Vivian S; Halabi, Carmen M; Hoffman, Erin P; Carmichael, Nikkola; Leshchiner, Ignaty; Lian, Christine G; Bierhals, Andrew J; Vuzman, Dana; Mecham, Robert P; Frank, Natasha Y; Stitziel, Nathan O

    2016-08-01

    Thoracic aortic aneurysms and dissections (TAAD) represent a substantial cause of morbidity and mortality worldwide. Many individuals presenting with an inherited form of TAAD do not have causal mutations in the set of genes known to underlie disease. Using whole-genome sequencing in two first cousins with TAAD, we identified a missense mutation in the lysyl oxidase (LOX) gene (c.893T > G encoding p.Met298Arg) that cosegregated with disease in the family. Using clustered regularly interspaced short palindromic repeats (CRISPR)/clustered regularly interspaced short palindromic repeats-associated protein-9 nuclease (Cas9) genome engineering tools, we introduced the human mutation into the homologous position in the mouse genome, creating mice that were heterozygous and homozygous for the human allele. Mutant mice that were heterozygous for the human allele displayed disorganized ultrastructural properties of the aortic wall characterized by fragmented elastic lamellae, whereas mice homozygous for the human allele died shortly after parturition from ascending aortic aneurysm and spontaneous hemorrhage. These data suggest that a missense mutation in LOX is associated with aortic disease in humans, likely through insufficient cross-linking of elastin and collagen in the aortic wall. Mutation carriers may be predisposed to vascular diseases because of weakened vessel walls under stress conditions. LOX sequencing for clinical TAAD may identify additional mutation carriers in the future. Additional studies using our mouse model of LOX-associated TAAD have the potential to clarify the mechanism of disease and identify novel therapeutics specific to this genetic cause.

  17. Loss of function mutation in LOX causes thoracic aortic aneurysm and dissection in humans.

    Science.gov (United States)

    Lee, Vivian S; Halabi, Carmen M; Hoffman, Erin P; Carmichael, Nikkola; Leshchiner, Ignaty; Lian, Christine G; Bierhals, Andrew J; Vuzman, Dana; Mecham, Robert P; Frank, Natasha Y; Stitziel, Nathan O

    2016-08-01

    Thoracic aortic aneurysms and dissections (TAAD) represent a substantial cause of morbidity and mortality worldwide. Many individuals presenting with an inherited form of TAAD do not have causal mutations in the set of genes known to underlie disease. Using whole-genome sequencing in two first cousins with TAAD, we identified a missense mutation in the lysyl oxidase (LOX) gene (c.893T > G encoding p.Met298Arg) that cosegregated with disease in the family. Using clustered regularly interspaced short palindromic repeats (CRISPR)/clustered regularly interspaced short palindromic repeats-associated protein-9 nuclease (Cas9) genome engineering tools, we introduced the human mutation into the homologous position in the mouse genome, creating mice that were heterozygous and homozygous for the human allele. Mutant mice that were heterozygous for the human allele displayed disorganized ultrastructural properties of the aortic wall characterized by fragmented elastic lamellae, whereas mice homozygous for the human allele died shortly after parturition from ascending aortic aneurysm and spontaneous hemorrhage. These data suggest that a missense mutation in LOX is associated with aortic disease in humans, likely through insufficient cross-linking of elastin and collagen in the aortic wall. Mutation carriers may be predisposed to vascular diseases because of weakened vessel walls under stress conditions. LOX sequencing for clinical TAAD may identify additional mutation carriers in the future. Additional studies using our mouse model of LOX-associated TAAD have the potential to clarify the mechanism of disease and identify novel therapeutics specific to this genetic cause. PMID:27432961

  18. Inhospital and Post-discharge Changes in Renal Function After Transcatheter Aortic Valve Replacement.

    Science.gov (United States)

    Blair, John E A; Brummel, Kent; Friedman, Julie L; Atri, Prashant; Sweis, Ranya N; Russell, Hyde; Ricciardi, Mark J; Malaisrie, S Chris; Davidson, Charles J; Flaherty, James D

    2016-02-15

    The aim of this study was to determine the influence of inhospital and post-discharge worsening renal function (WRF) on prognosis after transcatheter aortic valve replacement (TAVR). Severe chronic kidney disease and inhospital WRF are both associated with poor outcomes after TAVR. There are no data available on post-discharge WRF and outcomes. This was a single-center study evaluating all TAVR from June 1, 2008, to June 31, 2014. WRF was defined as an increase in serum creatinine of ≥0.3 mg/dl. Inhospital WRF was measured from day 0 until discharge or day 7 if the hospitalization was >7 days. Post-discharge WRF was measured at 30 days after discharge. Descriptive statistics, Kaplan-Meier time-to-event analysis, and multivariate logistic regression were used. In a series of 208 patients who underwent TAVR, 204 with complete renal function data were used in the inhospital analysis and 168 who returned for the 30-day follow-up were used in the post-discharge analysis. Inhospital WRF was seen in 28%, whereas post-discharge WRF in 12%. Inhospital and post-discharge WRF were associated with lower rates of survival; however, after multivariate analysis, only post-discharge WRF remained a predictor of 1-year mortality (hazard ratio 1.18, p = 0.030 for every 1 mg/dl increase in serum creatinine). In conclusion, the rate of inhospital WRF is higher than the rate of post-discharge WRF after TAVR, and post-discharge WRF is more predictive of mortality than inhospital WRF.

  19. Determinants of Invasively Measured Aortic Pulse Pressure and its Relationship with B-type Natriuretic Peptides in Stable Patients with Preserved Left Ventricular Systolic Function

    OpenAIRE

    Jarkovsky, J; J. Parenica; R. Miklik; M. Pavkova Goldbergova; P. Kala; L. Malaskova; Z. Cermakova; M. Poloczek; M. Vytiska; L. Kubková; S. Littnerova; K. Helanová; I. Parenicova; L. Dostalova; P. Kubena

    2012-01-01

    Background: Wide aortic pulse pressure (PP) and levels of natriuretic peptides were repeatedly demonstrated as predictors of cardiovascular morbidity and mortality even in a population without a history of heart disease. The aim of the work was to find determinants of invasively measured aortic pulse pressure and B-type natriuretic peptide (BNP), and a relationship of both markers in stable patients undergoing diagnostic coronary angiography with preserved left ventricle systolic function.Pop...

  20. Aortic Aneurysm

    Science.gov (United States)

    ... Most aneurysms are in the aorta, the main artery that runs from the heart through the chest and abdomen. There are two types of aortic aneurysm: Thoracic aortic aneurysms (TAA) - these occur in the part of the aorta running through the chest Abdominal aortic aneurysms (AAA) - these occur in the part ...

  1. How the type of input function affects the dynamic response of conducting polymer actuators

    International Nuclear Information System (INIS)

    There has been a growing interest in smart actuators typified by conducting polymer actuators, especially in their (i) fabrication, modeling and control with minimum external data and (ii) applications in bio-inspired devices, robotics and mechatronics. Their control is a challenging research problem due to the complex and nonlinear properties of these actuators, which cannot be predicted accurately. Based on an input-shaping technique, we propose a new method to improve the conducting polymer actuators’ command-following ability, while minimizing their electric power consumption. We applied four input functions with smooth characteristics to a trilayer conducting polymer actuator to experimentally evaluate its command-following ability under an open-loop control strategy and a simulated feedback control strategy, and, more importantly, to quantify how the type of input function affects the dynamic response of this class of actuators. We have found that the four smooth inputs consume less electrical power than sharp inputs such as a step input with discontinuous higher-order derivatives. We also obtained an improved transient response performance from the smooth inputs, especially under the simulated feedback control strategy, which we have proposed previously [X Xiang, R Mutlu, G Alici, and W Li, 2014 “Control of conducting polymer actuators without physical feedback: simulated feedback control approach with particle swarm optimization’, Journal of Smart Materials and Structure, 23]. The idea of using a smooth input command, which results in lower power consumption and better control performance, can be extended to other smart actuators. Consuming less electrical energy or power will have a direct effect on enhancing the operational life of these actuators. (paper)

  2. How the type of input function affects the dynamic response of conducting polymer actuators

    Science.gov (United States)

    Xiang, Xingcan; Alici, Gursel; Mutlu, Rahim; Li, Weihua

    2014-10-01

    There has been a growing interest in smart actuators typified by conducting polymer actuators, especially in their (i) fabrication, modeling and control with minimum external data and (ii) applications in bio-inspired devices, robotics and mechatronics. Their control is a challenging research problem due to the complex and nonlinear properties of these actuators, which cannot be predicted accurately. Based on an input-shaping technique, we propose a new method to improve the conducting polymer actuators’ command-following ability, while minimizing their electric power consumption. We applied four input functions with smooth characteristics to a trilayer conducting polymer actuator to experimentally evaluate its command-following ability under an open-loop control strategy and a simulated feedback control strategy, and, more importantly, to quantify how the type of input function affects the dynamic response of this class of actuators. We have found that the four smooth inputs consume less electrical power than sharp inputs such as a step input with discontinuous higher-order derivatives. We also obtained an improved transient response performance from the smooth inputs, especially under the simulated feedback control strategy, which we have proposed previously [X Xiang, R Mutlu, G Alici, and W Li, 2014 “Control of conducting polymer actuators without physical feedback: simulated feedback control approach with particle swarm optimization’, Journal of Smart Materials and Structure, 23]. The idea of using a smooth input command, which results in lower power consumption and better control performance, can be extended to other smart actuators. Consuming less electrical energy or power will have a direct effect on enhancing the operational life of these actuators.

  3. Surgery for severe aortic stenosis with low transvalvular gradient and poor left ventricular function – a single centre experience and review of the literature

    Directory of Open Access Journals (Sweden)

    Vchivkov Ilja

    2007-01-01

    Full Text Available Abstract Background A retrospective comparative study was designed to determine whether the transvalvular gradient has a predictive value in the assessment of operative outcome in patients with severe aortic stenosis and poor left ventricular function. Methods From a surgical database, a series of 30 consecutive patients, who underwent isolated aortic valve replacement for severe aortic stenosis with depressed left ventricular (LV function (EF 40 mmHg (n = 17. Both groups were then comparatively assessed with respect to perioperative organ functions and mortality. Results Both groups were well matched with respect to the preoperative clinical status. LG-Group had a larger aortic valve area, higher LVEDP, larger LVESD and LVEDD, and higher mean pulmonary pressures. The immediate postoperative outcome, hospital morbidity and mortality did not differ significantly among the groups. Conclusion In patients with severe aortic stenosis and poor LV function, the mean transvalvular gradient, although corresponds to reduced LV performance, has a limited prognostic value in the assessment of surgical outcome. Generally, operating on this select group of patients is safe.

  4. Reconstruction of an input function from a dynamic PET water image using multiple tissue curves

    Science.gov (United States)

    Kudomi, Nobuyuki; Maeda, Yukito; Yamamoto, Yuka; Nishiyama, Yoshihiro

    2016-08-01

    Quantification of cerebral blood flow (CBF) is important for the understanding of normal and pathologic brain physiology. When CBF is assessed using PET with {{\\text{H}}2} 15O or C15O2, its calculation requires an arterial input function, which generally requires invasive arterial blood sampling. The aim of the present study was to develop a new technique to reconstruct an image derived input function (IDIF) from a dynamic {{\\text{H}}2} 15O PET image as a completely non-invasive approach. Our technique consisted of using a formula to express the input using tissue curve with rate constant parameter. For multiple tissue curves extracted from the dynamic image, the rate constants were estimated so as to minimize the sum of the differences of the reproduced inputs expressed by the extracted tissue curves. The estimated rates were used to express the inputs and the mean of the estimated inputs was used as an IDIF. The method was tested in human subjects (n  =  29) and was compared to the blood sampling method. Simulation studies were performed to examine the magnitude of potential biases in CBF and to optimize the number of multiple tissue curves used for the input reconstruction. In the PET study, the estimated IDIFs were well reproduced against the measured ones. The difference between the calculated CBF values obtained using the two methods was small as around  text{H}}2} 15O PET imaging. This suggests the possibility of using a completely non-invasive technique to assess CBF in patho-physiological studies.

  5. Reconstruction of an input function from a dynamic PET water image using multiple tissue curves.

    Science.gov (United States)

    Kudomi, Nobuyuki; Maeda, Yukito; Yamamoto, Yuka; Nishiyama, Yoshihiro

    2016-08-01

    Quantification of cerebral blood flow (CBF) is important for the understanding of normal and pathologic brain physiology. When CBF is assessed using PET with [Formula: see text] (15)O or C(15)O2, its calculation requires an arterial input function, which generally requires invasive arterial blood sampling. The aim of the present study was to develop a new technique to reconstruct an image derived input function (IDIF) from a dynamic [Formula: see text] (15)O PET image as a completely non-invasive approach. Our technique consisted of using a formula to express the input using tissue curve with rate constant parameter. For multiple tissue curves extracted from the dynamic image, the rate constants were estimated so as to minimize the sum of the differences of the reproduced inputs expressed by the extracted tissue curves. The estimated rates were used to express the inputs and the mean of the estimated inputs was used as an IDIF. The method was tested in human subjects (n  =  29) and was compared to the blood sampling method. Simulation studies were performed to examine the magnitude of potential biases in CBF and to optimize the number of multiple tissue curves used for the input reconstruction. In the PET study, the estimated IDIFs were well reproduced against the measured ones. The difference between the calculated CBF values obtained using the two methods was small as around  <8% and the calculated CBF values showed a tight correlation (r  =  0.97). The simulation showed that errors associated with the assumed parameters were  <10%, and that the optimal number of tissue curves to be used was around 500. Our results demonstrate that IDIF can be reconstructed directly from tissue curves obtained through [Formula: see text] (15)O PET imaging. This suggests the possibility of using a completely non-invasive technique to assess CBF in patho-physiological studies. PMID:27401833

  6. Correcting partial volume artifacts of the arterial input function in quantitative cerebral perfusion MRI

    NARCIS (Netherlands)

    van Osch, MJP; Vonken, EJPA; Bakker, CJG; Viergever, MA

    2001-01-01

    To quantify cerebral perfusion with dynamic susceptibility contrast MRI (DSC-MRI), one needs to measure the arterial input function (AIF). Conventionally, one derives the contrast concentration from the DSC sequence by monitoring changes in either the amplitude or the phase signal on the assumption

  7. Functional Gene Differences in Soil Microbial Communities from Conventional, Low-Input, and Organic Farmlands

    OpenAIRE

    Xue, Kai; Wu, Liyou; Deng, Ye; He, Zhili; Van Nostrand, Joy,; Robertson, Philip G.; Schmidt, Thomas M; Zhou, Jizhong

    2013-01-01

    Various agriculture management practices may have distinct influences on soil microbial communities and their ecological functions. In this study, we utilized GeoChip, a high-throughput microarray-based technique containing approximately 28,000 probes for genes involved in nitrogen (N)/carbon (C)/sulfur (S)/phosphorus (P) cycles and other processes, to evaluate the potential functions of soil microbial communities under conventional (CT), low-input (LI), and organic (ORG) management systems a...

  8. Hemodynamic function of the standard St. Jude bileaflet disc valve has no clinical impact 10 years after aortic valve replacement

    DEFF Research Database (Denmark)

    Lund, Ole; Dorup, Inge; Emmertsen, Kristian;

    2005-01-01

    OBJECTIVES: Size mismatch and impaired left ventricular function have been shown to determine the hemodynamic function of the standard St. Jude bileaflet disc valve early after aortic valve replacement (AVR). We aimed to analyse St. Jude valve hemodynamic function and its clinical impact in the...... regurgitation were excluded from further analysis: they had significantly lower St. Jude valve gradient and left ventricular ejection fraction (LVEF) and larger mass index (LVMi) than 37 without. RESULTS: In the 37 patients without left sided valve regurgitation peak and mean gradients were inversely related to...... St. Jude valve geometric orifice area (GOA) indexed for either body surface area or left ventricular end-diastolic dimension (LVEDD). The gradients correlated directly with LVEDD but not with LVEF or LVMi. Eleven patients with hypertension had higher peak gradients (31+/-13 versus 22+/-8 mmHg, p<0...

  9. The Econometric Specification of Input Demand Systems Implied by Cost Function Representations

    OpenAIRE

    Keith R. McLaren; Xueyan Zhao

    2009-01-01

    In the case of input demand systems based on specification of technology by a Translog cost function, it is common to estimate either a system of share equations alone, or to supplement them by the cost function. By adding up, one of the share equations is excluded. In this paper it is argued that a system of n-1 share equations is essentially incomplete, whereas if the n-1 share equations are supplemented by the cost function the implied error structure is inadmissible. Similarly, if the tec...

  10. Effects of Ground Motion Input on the Derived Fragility Functions: Case study of 2010 Haiti Earthquake

    Science.gov (United States)

    Hancilar, Ufuk; Harmandar, Ebru; Çakti, Eser

    2014-05-01

    Empirical fragility functions are derived by statistical processing of the data on: i) Damaged and undamaged buildings, and ii) Ground motion intensity values at the buildings' locations. This study investigates effects of different ground motion inputs on the derived fragility functions. The previously constructed fragility curves (Hancilar et al. 2013), which rely on specific shaking intensity maps published by the USGS after the 2010 Haiti Earthquake, are compared with the fragility functions computed in the present study. Building data come from field surveys of 6,347 buildings that are grouped with respect to structural material type and number of stories. For damage assessment, the European Macroseismic Scale (EMS-98) damage grades are adopted. The simplest way to account for the variability in ground motion input could have been achieved by employing different ground motion prediction equations (GMPEs) and their standard variations. However, in this work, we prefer to rely on stochastically simulated ground motions of the Haiti earthquake. We employ five different source models available in the literature and calculate the resulting strong ground motion in time domain. In our simulations we also consider the local site effects by published studies on NEHRP site classes and micro-zoning maps of the city of Port-au-Prince. We estimate the regional distributions from the waveforms simulated at the same coordinates that we have damage information from. The estimated spatial distributions of peak ground accelerations and velocities, PGA and PGV respectively, are then used as input to fragility computations. The results show that changing the ground motion input causes significant variability in the resulting fragility functions.

  11. Estimation of the input function in dynamic positron emission tomography applied to fluorodeoxyglucose

    International Nuclear Information System (INIS)

    Positron Emission Tomography (PET) is a method of functional imaging, used in particular for drug development and tumor imaging. In PET, the estimation of the arterial plasmatic activity concentration of the non-metabolized compound (the 'input function') is necessary for the extraction of the pharmacokinetic parameters. These parameters enable the quantification of the compound dynamics in the tissues. This PhD thesis contributes to the study of the input function by the development of a minimally invasive method to estimate the input function. This method uses the PET image and a few blood samples. In this work, the example of the FDG tracer is chosen. The proposed method relies on compartmental modeling: it deconvoluates the three-compartment-model. The originality of the method consists in using a large number of regions of interest (ROIs), a large number of sets of three ROIs, and an iterative process. To validate the method, simulations of PET images of increasing complexity have been performed, from a simple image simulated with an analytic simulator to a complex image simulated with a Monte-Carlo simulator. After simulation of the acquisition, reconstruction and corrections, the images were segmented (through segmentation of an IRM image and registration between PET and IRM images) and corrected for partial volume effect by a variant of Rousset's method, to obtain the kinetics in the ROIs, which are the input data of the estimation method. The evaluation of the method on simulated and real data is presented, as well as a study of the method robustness to different error sources, for example in the segmentation, in the registration or in the activity of the used blood samples. (author)

  12. Characteristic operator functions for quantum input-plant-output models and coherent control

    Science.gov (United States)

    Gough, John E.

    2015-01-01

    We introduce the characteristic operator as the generalization of the usual concept of a transfer function of linear input-plant-output systems to arbitrary quantum nonlinear Markovian input-output models. This is intended as a tool in the characterization of quantum feedback control systems that fits in with the general theory of networks. The definition exploits the linearity of noise differentials in both the plant Heisenberg equations of motion and the differential form of the input-output relations. Mathematically, the characteristic operator is a matrix of dimension equal to the number of outputs times the number of inputs (which must coincide), but with entries that are operators of the plant system. In this sense, the characteristic operator retains details of the effective plant dynamical structure and is an essentially quantum object. We illustrate the relevance to model reduction and simplification definition by showing that the convergence of the characteristic operator in adiabatic elimination limit models requires the same conditions and assumptions appearing in the work on limit quantum stochastic differential theorems of Bouten and Silberfarb [Commun. Math. Phys. 283, 491-505 (2008)]. This approach also shows in a natural way that the limit coefficients of the quantum stochastic differential equations in adiabatic elimination problems arise algebraically as Schur complements and amounts to a model reduction where the fast degrees of freedom are decoupled from the slow ones and eliminated.

  13. Characteristic operator functions for quantum input-plant-output models and coherent control

    International Nuclear Information System (INIS)

    We introduce the characteristic operator as the generalization of the usual concept of a transfer function of linear input-plant-output systems to arbitrary quantum nonlinear Markovian input-output models. This is intended as a tool in the characterization of quantum feedback control systems that fits in with the general theory of networks. The definition exploits the linearity of noise differentials in both the plant Heisenberg equations of motion and the differential form of the input-output relations. Mathematically, the characteristic operator is a matrix of dimension equal to the number of outputs times the number of inputs (which must coincide), but with entries that are operators of the plant system. In this sense, the characteristic operator retains details of the effective plant dynamical structure and is an essentially quantum object. We illustrate the relevance to model reduction and simplification definition by showing that the convergence of the characteristic operator in adiabatic elimination limit models requires the same conditions and assumptions appearing in the work on limit quantum stochastic differential theorems of Bouten and Silberfarb [Commun. Math. Phys. 283, 491-505 (2008)]. This approach also shows in a natural way that the limit coefficients of the quantum stochastic differential equations in adiabatic elimination problems arise algebraically as Schur complements and amounts to a model reduction where the fast degrees of freedom are decoupled from the slow ones and eliminated

  14. ASYMPTOTICAL STABILITY OFNON-AUTONOMOUS DISCRETE-TIME NEURAL NETWORKS WITH GENERALIZED INPUT-OUTPUT FUNCTION

    Institute of Scientific and Technical Information of China (English)

    阮炯; 王军平; 郭德典

    2004-01-01

    In this paper, we first introduce the model of discrete-time neural networks with generalized input-output function and present a proof of the existence of a fixed point by Schauder fixed-point principle. Secondly, we study the uniformly asymptotical stability of equilibrium in non-autonomous discrete-time neural networks and give some sufficient conditions that guarantee the stability of it by using the converse theorem of Lyapunov function. Finally, several examples and numerical simulations are given to illustrate and reinforce our theories.

  15. Minimally invasive input function for 2-{sup 18}F-fluoro-A-85380 brain PET studies

    Energy Technology Data Exchange (ETDEWEB)

    Zanotti-Fregonara, Paolo [National Institute of Mental Health, NIH, Molecular Imaging Branch, Bethesda, MD (United States); Maroy, Renaud; Peyronneau, Marie-Anne; Trebossen, Regine [CEA, DSV, I2BM, Service Hospitalier Frederic Joliot, Orsay (France); Bottlaender, Michel [CEA, DSV, I2BM, NeuroSpin, Gif-sur-Yvette (France)

    2012-04-15

    Quantitative neuroreceptor positron emission tomography (PET) studies often require arterial cannulation to measure input function. While population-based input function (PBIF) would be a less invasive alternative, it has only rarely been used in conjunction with neuroreceptor PET tracers. The aims of this study were (1) to validate the use of PBIF for 2-{sup 18}F-fluoro-A-85380, a tracer for nicotinic receptors; (2) to compare the accuracy of measures obtained via PBIF to those obtained via blood-scaled image-derived input function (IDIF) from carotid arteries; and (3) to explore the possibility of using venous instead of arterial samples for both PBIF and IDIF. Ten healthy volunteers underwent a dynamic 2-{sup 18}F-fluoro-A-85380 brain PET scan with arterial and, in seven subjects, concurrent venous serial blood sampling. PBIF was obtained by averaging the normalized metabolite-corrected arterial input function and subsequently scaling each curve with individual blood samples. IDIF was obtained from the carotid arteries using a blood-scaling method. Estimated Logan distribution volume (V{sub T}) values were compared to the reference values obtained from arterial cannulation. For all subjects, PBIF curves scaled with arterial samples were similar in shape and magnitude to the reference arterial input function. The Logan V{sub T} ratio was 1.00 {+-} 0.05; all subjects had an estimation error <10%. IDIF gave slightly less accurate results (V{sub T} ratio 1.03 {+-} 0.07; eight of ten subjects had an error <10%). PBIF scaled with venous samples yielded inaccurate results (V{sub T} ratio 1.13 {+-} 0.13; only three of seven subjects had an error <10%). Due to arteriovenous differences at early time points, IDIF could not be calculated using venous samples. PBIF scaled with arterial samples accurately estimates Logan V{sub T} for 2-{sup 18}F-fluoro-A-85380. Results obtained with PBIF were slightly better than those obtained with IDIF. Due to arteriovenous concentration

  16. On the generation of bionic pulses with conventional piezoelectric transducers by proper design of the input driving function

    OpenAIRE

    Cobo-Parra, P.; CarbÓ-FitÉ, R.

    1994-01-01

    This paper concerns with the capacity of piezoelectric transducers to generate bionic pulses, by proper design of the input driving function which equalizes their transfer function. Firstly, the transfer function is measured by performing the transducer in the pinger mode. The measured transfer function, together with the parameters of the desired bionic pulse (i.e. central frequency, stretching and chirp), are the inputs to a program to calculate the voltage function which should drive the t...

  17. Synthesis of a Robust Multiobserver for the Estimation of Unknown Inputs Using the Piecewise Quadratic Functions

    Directory of Open Access Journals (Sweden)

    Elyes Maherzi

    2010-01-01

    Full Text Available Problem statement: The estimation of states and the unknown inputs of a nonlinear system described by a multimodel are done by a multiobserver. The stabilization of the multiobserver calls upon uses both quadratic and no quadratic functions of Lyapunov. Although the stabilization using the quadratic approach is interesting from the point of view implementation, the step showed its limits for the multimodel. However, the problem paused by the quadratic method lies in the obligation to satisfy several LMI with respect to the same Lyapunov matrix P, these results are shown very conservative. Approach: To reduce the conservatism of the quadratic approach we propose another approach which is exclusively based on Lyapunov piecewise quadratic functions. The conditions obtained by the stabilization of the multiobserver are expressed in term of matrix inequalities with constraints on the matrices rank. Results: The estimation of both states and unknown inputs of a multimodel using the quadratic approach per pieces leads to results less conservative than the quadratic approach. Academic examples illustrate the robustness of the piecewise quadratic approach. Conclusion: In this article we proposed new sufficient conditions of stability of a multiobserver able to the estimation of states and unknown inputs of a nonlinear system describes by a multimodel subjected to the influence of the unknown inputs. The study in was carried out by considering two approaches. The first approach is based on Lyapunov quadratic functions; it is significant to note the great difficulty in finding satisfying results by this approach for the multimodel systems. For this reason we proposed an approach based on piecewise quadratic functions which led to interesting results (proposition 1 and less conservative than the quadratic approach. The conditions suggested in this article concern both the multiobserver stabilization and the estimation of states and the

  18. Mechanical analysis of functionally graded plates based on the input data of metallographic diagrams

    Institute of Scientific and Technical Information of China (English)

    CAO ZhiYuan; TANG ShouGao; CHENG HongMei

    2008-01-01

    A microelement method for scale-span analysis of material microstructure and member macro re-sponse has been proposed. Instead of material parameter input for traditional mechanical analysis, the method is based on the input of metallographic diagram information. In order to express the material microstructure, this method arranges concentrated microelements in ordinary finite element before calculation, and transfers the node degrees of freedom of each microelement into the ones of the same finite element via compatibility conditions. This method can realize direct transition analysis from ma-terial microstructure to macro responses of members, while computation elements and degrees of freedom are equal to those of ordinary FEM. Based on the complicated microstructure diagrams pro-posed by material metallographic diagram, the mechanics responses of functionally graded plates are calculated and 3-D distributions of macro-mechanical variables and identical stress lines tendency on microstructure are given.

  19. Individualization of transfer function in estimation of central aortic pressure from the peripheral pulse is not required in patients at rest.

    Science.gov (United States)

    Westerhof, Berend E; Guelen, Ilja; Stok, Wim J; Lasance, Han A J; Ascoop, Carl A P L; Wesseling, Karel H; Westerhof, Nico; Bos, Willem Jan W; Stergiopulos, Nikos; Spaan, Jos A E

    2008-12-01

    Central aortic pressure gives better insight into ventriculo-arterial coupling and better prognosis of cardiovascular complications than peripheral pressures. Therefore transfer functions (TF), reconstructing aortic pressure from peripheral pressures, are of great interest. Generalized TFs (GTF) give useful results, especially in larger study populations, but detailed information on aortic pressure might be improved by individualization of the TF. We found earlier that the time delay, representing the travel time of the pressure wave between measurement site and aorta is the main determinant of the TF. Therefore, we hypothesized that the TF might be individualized (ITF) using this time delay. In a group of 50 patients at rest, aged 28-66 yr (43 men), undergoing diagnostic angiography, ascending aortic pressure was 119 +/- 20/70 +/- 9 mmHg (systolic/diastolic). Brachial pressure, almost simultaneously measured using catheter pullback, was 131 +/- 18/67 +/- 9 mmHg. We obtained brachial-to-aorta ITFs using time delays optimized for the individual and a GTF using averaged delay. With the use of ITFs, reconstructed aortic pressure was 121 +/- 19/69 +/- 9 mmHg and the root mean square error (RMSE), as measure of difference in wave shape, was 4.1 +/- 2.0 mmHg. With the use of the GTF, reconstructed pressure was 122 +/- 19/69 +/- 9 mmHg and RMSE 4.4 +/- 2.0 mmHg. The augmentation index (AI) of the measured aortic pressure was 26 +/- 13%, and with ITF and GTF the AIs were 28 +/- 12% and 30 +/- 11%, respectively. Details of the wave shape were reproduced slightly better with ITF but not significantly, thus individualization of pressure transfer is not effective in resting patients. PMID:18845775

  20. Entrainment and phase-shifting by centrifugation abolished in mice lacking functional vestibular input

    Science.gov (United States)

    Fuller, Charles; Ringgold, Kristyn

    The circadian pacemaker can be phase shifted and entrained by appropriately timed locomotor activity, however the mechanism(s) involved remain poorly understood. Recent work in our lab has suggested the involvement of the vestibular otolith organs in activity-induced changes within the circadian timing system (CTS). For example, we have shown that changes in circa-dian period and phase in response to locomotion (wheel running) require functional macular gravity receptors. We believe the neurovestibular system is responsible for the transduction of gravitoinertial input associated with the types of locomotor activity that are known to af-fect the pacemaker. This study investigated the hypothesis that daily, timed gravitoinertial stimuli, as applied by centrifugation. would induce entrainment of circadian rhythms in only those animals with functional afferent vestibular input. To test this hypothesis, , chemically labyrinthectomized (Labx) mice, mice lacking macular vestibular input (head tilt or hets) and wildtype (WT) littermates were implanted i.p. with biotelemetry and individually housed in a 4-meter diameter centrifuge in constant darkness (DD). After 2 weeks in DD, the mice were exposed daily to 2G via centrifugation from 1000-1200 for 9 weeks. Only WT mice showed entrainment to the daily 2G pulse. The 2G pulse was then re-set to occur at 1200-1400 for 4 weeks. Only WT mice demonstrated a phase shift in response to the re-setting of the 2G pulse and subsequent re-entrainment to the new centrifugation schedule. These results provide further evidence that gravitoinertial stimuli require a functional vestibular system to both en-train and phase shift the CTS. Entrainment among only WT mice supports the role of macular gravity receptive cells in modulation of the CTS while also providing a functional mechanism by which gravitoinertial stimuli, including locomotor activity, may affect the pacemaker.

  1. Aortic stenting.

    Science.gov (United States)

    Droc, Ionel; Calinescu, Francisca Blanca; Droc, Gabriela; Blaj, Catalin; Dammrau, Rolf

    2015-01-01

    The approach to aortic pathology is nowadays more and more endovascular at both thoracic and abdominal levels. Thoracic stenting has gained worldwide acceptance as first intention to treat pathologies of the descending thoracic aorta. Indications have been extended to aortic arch aneurysms and also to diseases of the ascending aorta. The current devices in use for thoracic endovascular repair (TEVAR) are Medtronic Valiant, Gore TAG, Cook Tx2 and Jotec. The choice of the endograft depends on the thoracic aortic pathology and the anatomical suitability. The technological evolution of the abdominal aortic endografts was very rapid, arriving now at the fourth generation. We report the results of 55 elective cases of endovascular abdominal aortic repair (EVAR) performed in two vascular surgical centers in Romania and Germany. The prostheses used were 16 E-vita Abdominal XT, 12 Excluder, eight Talent, seven PowerLink, three Endurant and nine custom-made, fenestrated or branched from Jotec. The mean follow-up was 18 months with CT-scan, duplex ultrasound and contrast-enhanced ultrasound. The mortality was 2%. EVAR tends to become the gold standard for abdominal aortic aneurysm repair. Technological development of the devices with lowest profile introduction systems will permit to extend the anatomical indications to new frontiers. PMID:26200430

  2. Left ventricular myocardial function in congenital valvar aortic stenosis assessed by ultrasound tissue-velocity and strain-rate techniques.

    NARCIS (Netherlands)

    Kiraly, P.; Kapusta, L.; Thijssen, J.M.; Daniëls, O.

    2003-01-01

    A pilot study was performed to reveal the potentials of new echo Doppler techniques for the detection of myocardial changes due to congenital valvar aortic stenosis. A total of 24 patients, (age range 0.1 to 17 years), with various degrees of aortic stenosis, and 24 age- and gender-matched, healthy

  3. Functional cardiac MRI for assessment of aortic valve disease; Aortenklappenstenose im MRT mit Dynamik und 3D

    Energy Technology Data Exchange (ETDEWEB)

    Sagmeister, F.; Ritter, C.; Machann, W.; Koestler, H.; Hahn, D.; Beer, M. [Universitaetsklinikum Wuerzburg, Institut fuer Roentgendiagnostik, Wuerzburg (Germany); Herrmann, S.; Voelker, W.; Weidemann, F. [Universitaetsklinikum Wuerzburg, Medizinische Klinik I, Wuerzburg (Germany)

    2010-06-15

    Aortic valve disease shows a rising incidence with the increasing mean age of Western populations. The detection of hemodynamic parameters, which transcends the mere assessment of valve morphology, has an important future potential concerning classification of the severity of disease. MRI allows a non-invasive and a spatially flexible view of the aortic valve and the adjacent anatomic region, left ventricular outflow tract (LVOT) and ascending aorta. Moreover, the technique allows the determination of functional hemodynamic parameters, such as flow velocities and effective orifice areas. The new approach of a serial systolic planimetry velocity-encoded MRI sequence (VENC-MRI) facilitates the sizing of blood-filled cardiac structures with the registration of changes in magnitude during systole. Additionally, the subvalvular VENC-MRI measurements improve the clinically important exact determination of the LVOT area with respect to its specific eccentric configuration and its systolic deformity. (orig.) [German] Erworbene Erkrankungen der Aortenklappe wie die Aortenklappenstenose zeigen mit zunehmender Alterungstendenz unserer Gesellschaft eine ansteigende Inzidenz. Die Erfassung ueber die reine Klappenmorphologie hinausgehender haemodynamischer Parameter hat ein wichtiges zukuenftiges Potenzial zur Schweregradeinschaetzung. Die MRT erlaubt eine nichtinvasive und raeumlich flexible Darstellung der Aortenklappe sowie ihrer benachbarten anatomischen Strukturen (linksventrikulaerer Ausflusstrakt/LVOT, Aorta ascendens). Darueber hinaus ist eine Bestimmung funktioneller haemodynamischer Parameter wie Flussgeschwindigkeiten und effektiven Oeffnungsflaechen (EOeF) moeglich. Der neue Ansatz einer seriellen Planimetrie geschwindigkeitskodierter MRT-Sequenzen (Velocity-encoding- [VENC-]MRT) erlaubt die Groessenbestimmung flussdurchstroemter kardialer Strukturen und die Aufzeichnung ihrer dynamischen Groessenveraenderung waehrend der Systole. Zusaetzlich ermoeglicht die

  4. MRI-derived arterial input functions for PET kinetic modelling in rats

    International Nuclear Information System (INIS)

    Simultaneous PET–MR acquisition provides the high temporal and spatial resolution of MRI with the specificity of PET. In PET, accurate modelling of physiological function in vivo requires the time-activity curve of tracer in blood plasma, known as the arterial input function (AIF). As the gold standard method of blood sampling is inherently prohibitive in the small animal case, here we discuss how we prepare to rapidly sample MRI signals from gadolinium-doped tracer to obtain the tracer input functions from a simultaneous PET-MR measurement. ΔR2⁎ measurements taken from EPI images were used to obtain first pass bolus AIFs in the rat brain from DSC-MRI datasets of 5 rats. AIFs obtained using our automatic algorithm were found to be consistent between animals and compared well with manual methods without need for a priori voxel selection. A variable flip angle FLASH sequence used for T1 mapping was successfully tested in a phantom study, providing accurate measurements of Gd concentration

  5. Characterizing the Input-Output Function of the Olfactory-Limbic Pathway in the Guinea Pig

    Directory of Open Access Journals (Sweden)

    Gian Luca Breschi

    2015-01-01

    Full Text Available Nowadays the neuroscientific community is taking more and more advantage of the continuous interaction between engineers and computational neuroscientists in order to develop neuroprostheses aimed at replacing damaged brain areas with artificial devices. To this end, a technological effort is required to develop neural network models which can be fed with the recorded electrophysiological patterns to yield the correct brain stimulation to recover the desired functions. In this paper we present a machine learning approach to derive the input-output function of the olfactory-limbic pathway in the in vitro whole brain of guinea pig, less complex and more controllable than an in vivo system. We first experimentally characterized the neuronal pathway by delivering different sets of electrical stimuli from the lateral olfactory tract (LOT and by recording the corresponding responses in the lateral entorhinal cortex (l-ERC. As a second step, we used information theory to evaluate how much information output features carry about the input. Finally we used the acquired data to learn the LOT-l-ERC “I/O function,” by means of the kernel regularized least squares method, able to predict l-ERC responses on the basis of LOT stimulation features. Our modeling approach can be further exploited for brain prostheses applications.

  6. Characterizing the Input-Output Function of the Olfactory-Limbic Pathway in the Guinea Pig.

    Science.gov (United States)

    Breschi, Gian Luca; Ciliberto, Carlo; Nieus, Thierry; Rosasco, Lorenzo; Taverna, Stefano; Chiappalone, Michela; Pasquale, Valentina

    2015-01-01

    Nowadays the neuroscientific community is taking more and more advantage of the continuous interaction between engineers and computational neuroscientists in order to develop neuroprostheses aimed at replacing damaged brain areas with artificial devices. To this end, a technological effort is required to develop neural network models which can be fed with the recorded electrophysiological patterns to yield the correct brain stimulation to recover the desired functions. In this paper we present a machine learning approach to derive the input-output function of the olfactory-limbic pathway in the in vitro whole brain of guinea pig, less complex and more controllable than an in vivo system. We first experimentally characterized the neuronal pathway by delivering different sets of electrical stimuli from the lateral olfactory tract (LOT) and by recording the corresponding responses in the lateral entorhinal cortex (l-ERC). As a second step, we used information theory to evaluate how much information output features carry about the input. Finally we used the acquired data to learn the LOT-l-ERC "I/O function," by means of the kernel regularized least squares method, able to predict l-ERC responses on the basis of LOT stimulation features. Our modeling approach can be further exploited for brain prostheses applications.

  7. Assessing the applicability of global CFC and SF6 input functions to groundwater dating in Britain

    International Nuclear Information System (INIS)

    Chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6) are increasingly being used to date groundwaters. While these trace gases are generally well-mixed in the atmosphere, local atmospheric excesses (LAEs) have been found in some parts of the world, thereby affecting the interpretation of data from groundwater studies. To investigate the possibility of LAEs in Britain, mixing ratios of CFC-11, CFC-12 and SF6 were measured in soil gases from two large conurbations (London and Birmingham) and a smaller urban area, Bristol. Most mixing ratios for CFC-12 and SF6 were 6 input functions based on the NH-AMR curves appears justified for Britain. (author)

  8. Analysis of Partial Volume Effects on Arterial Input Functions Using Gradient Echo: A Simulation Study

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Mikkelsen, Irene Klærke; Pedersen, Michael;

    2009-01-01

    Absolute blood flow and blood volume measurements using perfusion weighted MRI require an accurately measured arterial input function (AIF). Because of limited spatial resolution of MR images, AIF voxels cannot be placed completely within a feeding artery. We present a two-compartment model...... of an AIF voxel including the relaxation properties of blood and tissue. Artery orientations parallel and perpendicular to the main magnetic field were investigated and AIF voxels were modeled to either include or be situated close to a large artery. The impact of partial volume effects on quantitative...

  9. Average arterial input function for quantitative dynamic contrast enhanced magnetic resonance imaging of neck nodal metastases

    OpenAIRE

    Shukla-Dave, Amita; Lee, Nancy; Stambuk, Hilda; Wang, YA; Huang, Wei; Howard T Thaler; Patel, Snehal G.; Shah, Jatin P.; Koutcher, Jason A

    2009-01-01

    Background The present study determines the feasibility of generating an average arterial input function (Avg-AIF) from a limited population of patients with neck nodal metastases to be used for pharmacokinetic modeling of dynamic contrast-enhanced MRI (DCE-MRI) data in clinical trials of larger populations. Methods Twenty patients (mean age 50 years [range 27–77 years]) with neck nodal metastases underwent pretreatment DCE-MRI studies with a temporal resolution of 3.75 to 7.5 sec on a 1.5T c...

  10. A time-resolved model of the mesospheric Na layer: constraints on the meteor input function

    Directory of Open Access Journals (Sweden)

    J. M. C. Plane

    2004-01-01

    Full Text Available A time-resolved model of the Na layer in the mesosphere/lower thermosphere region is described, where the continuity equations for the major sodium species Na, Na+ and NaHCO3 are solved explicity, and the other short-lived species are treated in steady-state. It is shown that the diurnal variation of the Na layer can only be modelled satisfactorily if sodium species are permanently removed below about 85 km, both through the dimerization of NaHCO3 and the uptake of sodium species on meteoric smoke particles that are assumed to have formed from the recondensation of vaporized meteoroids. When the sensitivity of the Na layer to the meteoroid input function is considered, an inconsistent picture emerges. The ratio of the column abundance of Na+ to Na is shown to increase strongly with the average meteoroid velocity, because the Na is injected at higher altitudes. Comparison with a limited set of Na+ measurements indicates that the average meteoroid velocity is probably less than about 25 km s-1, in agreement with velocity estimates from conventional meteor radars, and considerably slower than recent observations made by wide aperture incoherent scatter radars. The Na column abundance is shown to be very sensitive to the meteoroid mass input rate, and to the rate of vertical transport by eddy diffusion. Although the magnitude of the eddy diffusion coefficient in the 80–90 km region is uncertain, there is a consensus between recent models using parameterisations of gravity wave momentum deposition that the average value is less than 3×105 cm2 s-1. This requires that the global meteoric mass input rate is less than about 20 td-1, which is closest to estimates from incoherent scatter radar observations. Finally, the diurnal variation in the meteoroid input rate only slight perturbs the Na layer, because the residence time of Na in the layer is several days, and diurnal effects are effectively averaged out.

  11. Aortic Arch Calcification Predicts the Renal Function Progression in Patients with Stage 3 to 5 Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Lung-Chih Li

    2015-01-01

    Full Text Available Introduction. The presence of aortic arch calcification (AoAC and cardiomegaly on chest radiography has been demonstrated as important risk factors for cardiovascular mortality in patients with chronic kidney disease (CKD. However, the interrelationship among AoAC, cardiomegaly, and renal function progression remains unclear. The aim of this study is to assess whether AoAC and cardiomegaly are independently associated with the renal function progression in patients with stages 3–5 CKD. Methods. We retrospectively determined AoAC and cardiomegaly by chest X-ray in 237 patients, followed up for at least three years without entering dialysis and classified into 4 groups according to the presence or absence of AoAC and cardiomegaly. The change in renal function was measured by the slope of estimated glomerular filtration rate (eGFR. Results. Of the 237 patients, the rate of eGFR decline was significantly higher in the group with coexistence of AoAC and cardiomegaly than any other groups. Baseline AoAC and proteinuria were independently associated with eGFR decline. AoAC were independently determined by age, eGFR slope, and cardiomegaly. Conclusions. The coexistence of AoAC and cardiomegaly is associated with faster eGFR decline. AoAC is an independent determinant of renal outcomes in patients with CKD stages 3–5.

  12. Development of Input Function Measurement System for Small Animal PET Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Guk; Kim, Byung Su; Kim, Jin Su [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2010-10-15

    For quantitative measurement of radioactivity concentration in tissue and a validated tracer kinetic model, the high sensitive detection system has been required for blood sampling. With the accurate measurement of time activity curves (TACs) of labeled compounds in blood (plasma) enable to provide quantitative information on biological parameters of interest in local tissue. Especially, the development of new tracers for PET imaging requires knowledge of the kinetics of the tracer in the body and in arterial blood and plasma. Conventional approaches of obtaining an input function are to sample arterial blood sequentially by manual as a function of time. Several continuous blood sampling systems have been developed and used in nuclear medicine research field to overcome the limited temporal resolution in sampling by the conventional method. In this work, we developed the high sensitive and unique geometric design of GSO detector for small animal blood activity measurement

  13. Functional identification of the input-output transforms of mammalian motoneurones.

    Science.gov (United States)

    Binder, M D; Poliakov, A V; Powers, R K

    1999-01-01

    transform could be predicted from the mean firing rate and the linear impulse response, yielding a relatively simple, general description of the motoneurone's input-output function.

  14. [Aortic aneurysm].

    Science.gov (United States)

    Villar, Fernando; Pedro-Botet, Juan; Vila, Ramón; Lahoz, Carlos

    2013-01-01

    Aortic aneurysm is one important cause of death in our country. The prevalence of abdominal aortic aneurism (AAA) is around 5% for men older than 50 years of age. Some factors are associated with increased risk for AAA: age, hypertension, hypercholesterolemia, cardiovascular disease and, in particular, smoking. The medical management of patients with an AAA includes cardiovascular risk treatment, particularly smoking cessation. Most of major societies guidelines recommend ultrasonography screening for AAA in men aged 65 to 75 years who have ever smoked because it leads to decreased AAA-specific mortality. PMID:24238836

  15. The Micrometeor Input Function: A study using model predictions HPLA radar meteor observations

    Science.gov (United States)

    Janches, D.; Fentzke, J. T.; Sparks, J. J.

    2008-05-01

    In this work we use a semi-empirical model of the Micrometeor Input Function (MIF) together with meteor head- echo observations obtained with two High Power and Large Aperture (HPLA) radars to study the seasonal and geographical dependence of the meteoric flux in the upper atmosphere. The model includes an initial mass flux that is provided by six known meteor sources (i.e. orbital families of dust) as well as detailed modeling of meteoroid atmospheric entry and ablation physics. In addition, we use a simple ionization model to treat radar sensitivity issues by defining minimum electron volume density production thresholds required in the meteor head-echo plasma for detection. This simplified approach works well because we use observations from two radars with similar frequencies, but different sensitivities and locations. This methodology allows us the explore the initial input of particles and how it manifests in different parts of the MLT as observed by these instruments without the need to invoke more sophisticated plasma models, which are under current development. The comparisons between model predictions and radar observations show excellent agreement between diurnal, seasonal, and latitudinal variability of the detected meteor rate and radial velocity distributions, allowing us to understand how individual meteoroid populations contribute to the overall flux at a particular location and season.

  16. Transient evoked otoacoustic emission input/output function and cochlear reflectivity: experiment and model.

    Science.gov (United States)

    Sisto, Renata; Moleti, Arturo

    2008-11-01

    The complex input/output function of transient evoked otoacoustic emissions is evaluated at different stimulus levels. The experimental response functions were best fitted to the reflectivity functions predicted by theoretical one-dimensional transmission-line models in the perturbative limit. Along with the otoacoustic emission sources usually considered, linear reflection from roughness (place-fixed) and nonlinear distortion (wave-fixed), a wave-fixed scattering potential is also considered, associated with the breaking of the scale-invariance symmetry, as a new additional mechanism for otoacoustic emission generation. A good fit was obtained, across stimulus level and frequency, for roughness, and not for nonlinear distortion, nor for scale-invariance violation. The phase-gradient delay of the same transient evoked otoacoustic emissions was consistent with the latency measured using a wavelet time-frequency technique, at all stimulus levels and frequencies. The results suggest that cochlear reflectivity is dominated by a component with a rapidly rotating phase, at all stimulus levels, in apparent contradiction with the usual assumption that, at high stimulus levels, a significant contribution to the transient evoked otoacoustic response should come from nonlinear distortion. Possible interpretations of this phenomenology are critically reviewed and discussed, considering the theoretical uncertainties and the limitations of the experimental technique. PMID:19045787

  17. Quantitative assessment of systolic left ventricular function with speckle-tracking echocardiography in adult patients with repaired aortic coarctation.

    Science.gov (United States)

    Menting, Myrthe E; van Grootel, Roderick W J; van den Bosch, Annemien E; Eindhoven, Jannet A; McGhie, Jackie S; Cuypers, Judith A A E; Witsenburg, Maarten; Helbing, Willem A; Roos-Hesselink, Jolien W

    2016-05-01

    Despite successful aortic coarctation (CoA) repair, systemic hypertension often recurs which may influence left ventricular (LV) function. We aimed to detect early LV dysfunction using LV global longitudinal strain (GLS) in adults with repaired CoA, and to identify associations with patient and echocardiographic characteristics. In this cross-sectional study, patients with repaired CoA and healthy controls were recruited prospectively. All subjects underwent echocardiography, ECG and blood sampling within 1 day. With speckle-tracking echocardiography, we assessed LV GLS on the apical four-, three- and two-chamber views. We included 150 subjects: 75 patients (57 % male, age 33.4 ± 12.8 years, age at repair 2.5 [IQR: 0.1-11.1] years) and 75 healthy controls of similar sex and age. LV GLS was lower in patients than in controls (-17.1 ± 2.3 vs. -20.2 ± 1.6 %, P detection of ventricular dysfunction. PMID:26780661

  18. Comparison of Parameter Estimations Using Dual-Input and Arterial-Input in Liver Kinetic Studies of FDG Metabolism.

    Science.gov (United States)

    Cui, Yunfeng; Bai, Jing

    2005-01-01

    Liver kinetic study of [18F]2-fluoro-2-deoxy-D-glucose (FDG) metabolism in human body is an important tool for functional modeling and glucose metabolic rate estimation. In general, the arterial blood time-activity curve (TAC) and the tissue TAC are required as the input and output functions for the kinetic model. For liver study, however, the arterial-input may be not consistent with the actual model input because the liver has a dual blood supply from the hepatic artery (HA) and the portal vein (PV) to the liver. In this study, the result of model parameter estimation using dual-input function is compared with that using arterial-input function. First, a dynamic positron emission tomography (PET) experiment is performed after injection of FDG into the human body. The TACs of aortic blood, PV blood, and five regions of interest (ROIs) in liver are obtained from the PET image. Then, the dual-input curve is generated by calculating weighted sum of both the arterial and PV input curves. Finally, the five liver ROIs' kinetic parameters are estimated with arterial-input and dual-input functions respectively. The results indicate that the two methods provide different parameter estimations and the dual-input function may lead to more accurate parameter estimation.

  19. Relation of osteoprotegerin in severe aortic valve stenosis to postoperative outcome and left ventricular function

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Videbæk, Lars; Poulsen, Mikael K;

    2013-01-01

    . Preoperative OPG was associated with age, EuroSCORE, and preoperative functional capacity. Despite similar ejection fraction and diastolic function among groups, longitudinal LV systolic function consistently decreased and markers of filling pressure increased across groups. During median follow-up of 4 years...

  20. Aortic biomechanics in hypertrophic cardiomyopathy

    Science.gov (United States)

    Badran, Hala Mahfouz; Soltan, Ghada; Faheem, Nagla; Elnoamany, Mohamed Fahmy; Tawfik, Mohamed; Yacoub, Magdi

    2015-01-01

    Background: Ventricular-vascular coupling is an important phenomenon in many cardiovascular diseases. The association between aortic mechanical dysfunction and left ventricular (LV) dysfunction is well characterized in many disease entities, but no data are available on how these changes are related in hypertrophic cardiomyopathy (HCM). Aim of the work: This study examined whether HCM alone is associated with an impaired aortic mechanical function in patients without cardiovascular risk factors and the relation of these changes, if any, to LV deformation and cardiac phenotype. Methods: 141 patients with HCM were recruited and compared to 66 age- and sex-matched healthy subjects as control group. Pulse pressure, aortic strain, stiffness and distensibility were calculated from the aortic diameters measured by M-mode echocardiography and blood pressure obtained by sphygmomanometer. Aortic wall systolic and diastolic velocities were measured using pulsed wave Doppler tissue imaging (DTI). Cardiac assessment included geometric parameters and myocardial deformation (strain and strain rate) and mechanical dyssynchrony. Results: The pulsatile change in the aortic diameter, distensibility and aortic wall systolic velocity (AWS') were significantly decreased and aortic stiffness index was increased in HCM compared to control (P < .001) In HCM AWS' was inversely correlated to age(r = − .32, P < .0001), MWT (r = − .22, P < .008), LVMI (r = − .20, P < .02), E/Ea (r = − .16, P < .03) LVOT gradient (r = − 19, P < .02) and severity of mitral regurg (r = − .18, P < .03) but not to the concealed LV deformation abnormalities or mechanical dyssynchrony. On multivariate analysis, the key determinant of aortic stiffness was LV mass index and LVOT obstruction while the role LV dysfunction in aortic stiffness is not evident in this population. Conclusion: HCM is associated with abnormal aortic mechanical properties. The severity of cardiac

  1. Modeling the Meteoroid Input Function at Mid-Latitude Using Meteor Observations by the MU Radar

    Science.gov (United States)

    Pifko, Steven; Janches, Diego; Close, Sigrid; Sparks, Jonathan; Nakamura, Takuji; Nesvorny, David

    2012-01-01

    The Meteoroid Input Function (MIF) model has been developed with the purpose of understanding the temporal and spatial variability of the meteoroid impact in the atmosphere. This model includes the assessment of potential observational biases, namely through the use of empirical measurements to characterize the minimum detectable radar cross-section (RCS) for the particular High Power Large Aperture (HPLA) radar utilized. This RCS sensitivity threshold allows for the characterization of the radar system s ability to detect particles at a given mass and velocity. The MIF has been shown to accurately predict the meteor detection rate of several HPLA radar systems, including the Arecibo Observatory (AO) and the Poker Flat Incoherent Scatter Radar (PFISR), as well as the seasonal and diurnal variations of the meteor flux at various geographic locations. In this paper, the MIF model is used to predict several properties of the meteors observed by the Middle and Upper atmosphere (MU) radar, including the distributions of meteor areal density, speed, and radiant location. This study offers new insight into the accuracy of the MIF, as it addresses the ability of the model to predict meteor observations at middle geographic latitudes and for a radar operating frequency in the low VHF band. Furthermore, the interferometry capability of the MU radar allows for the assessment of the model s ability to capture information about the fundamental input parameters of meteoroid source and speed. This paper demonstrates that the MIF is applicable to a wide range of HPLA radar instruments and increases the confidence of using the MIF as a global model, and it shows that the model accurately considers the speed and sporadic source distributions for the portion of the meteoroid population observable by MU.

  2. Estimating the basilar-membrane input-output function in normal-hearing and hearing-impaired listeners

    DEFF Research Database (Denmark)

    Jepsen, Morten Løve; Dau, Torsten

    To partly characterize the function of cochlear processing in humans, the basilar membrane (BM) input-output function can be estimated. In recent studies, forward masking has been used to estimate BM compression. If an on-frequency masker is processed compressively, while an off-frequency masker...... processing at medium levels. If a signal can be masked by a low-level on-frequency masker such that signal and masker fall in the linear region of the I/O-function, then a steeper GOM function is expected. The knee-point can then be estimated in the input level region where the GOM changes significantly...... higher input levels and compression was similar to that of NH listeners....

  3. Transcatheter Aortic Valve Replacement in a Nonagenarian

    OpenAIRE

    Kneitz, Abby; Clifton, William; Kar, Biswajit; Delgado, Reynolds M.

    2013-01-01

    Approximately 30% to 40% of elderly patients with severe, symptomatic aortic valve stenosis are deemed ineligible for surgery because of high perioperative risk. We describe the use of an alternative transfemoral approach known as transcatheter aortic valve implantation in a nonagenarian patient with severe aortic stenosis. Our patient recovered successfully, and by the time of her most recent follow-up visit, 7 months after the procedure, she had regained a substantial degree of function. Th...

  4. Chaos and asymptotical stability in discrete-time recurrent neural networks with generalized input-output function

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    We theoretically investigate the asymptotical stability, localbifurcations and chaos of discrete-time recurrent neural networks with the form ofwhere the input-output function is defined as a generalized sigmoid function, such as vi=tanh(μiui), etc. Numerical simulations are also provided to demonstrate the theoretical results.

  5. Functional properties of GABA synaptic inputs onto GABA neurons in monkey prefrontal cortex

    NARCIS (Netherlands)

    D.C. Rotaru (Diana C.); C. Olezene (Cameron); T. Miyamae (Takeaki); N.V. Povysheva (Nadezhda V.); A.V. Zaitsev (Aleksey V.); D.A. Lewis (David A.); G. Gonzalez-Burgos (Guillermo)

    2015-01-01

    textabstractIn rodent cortex GABAA receptor (GABAAR)-mediated synapses are a significant source of input onto GABA neurons, and the properties of these inputs vary among GABA neuron subtypes that differ in molecular markers and firing patterns. Some features of cortical interne

  6. Determination of arterial input function in dynamic susceptibility contrast MRI using group independent component analysis technique

    Science.gov (United States)

    Chen, Sharon; Liu, Ho-Ling; Yang, Yihong; Hsu, Yuan-Yu; Chuang, Keh-Shih

    2006-12-01

    Quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) requires the determination of the arterial input function (AIF). The segmentation of surrounding tissue by manual selection is error-prone due to the partial volume artifacts. Independent component analysis (ICA) has the advantage in automatically decomposing the signals into interpretable components. Recently group ICA technique has been applied to fMRI study and showed reduced variance caused by motion artifact and noise. In this work, we investigated the feasibility and efficacy of the use of group ICA technique to extract the AIF. Both simulated and in vivo data were analyzed in this study. The simulation data of eight phantoms were generated using randomized lesion locations and time activity curves. The clinical data were obtained from spin-echo EPI MR scans performed in seven normal subjects. Group ICA technique was applied to analyze data through concatenating across seven subjects. The AIFs were calculated from the weighted average of the signals in the region selected by ICA. Preliminary results of this study showed that group ICA technique could not extract accurate AIF information from regions around the vessel. The mismatched location of vessels within the group reduced the benefits of group study.

  7. Seasonal study of the micrometeor input function at high latitudes using PFISR

    Science.gov (United States)

    Sparks, J.; Fentzke, J. T.; Janches, D.; Nicolls, M. J.; Heinselman, C.

    2007-12-01

    We present a seasonal study of the micrometeor input function (MIF) at high latitudes using meteor head-echo radar observations performed with the new Poker Flat Incoherent Scatter Radar (PFISR). This flux is responsible for a number of atmospheric phenomena, one of which, may be the production of meteoric smoke which would act as a condensation nuclei in the formation of ice particles in the polar mesosphere. The observations were performed during 24 hrs periods near the summer and winter solstices and spring and autumn equinoxes, times at which the seasonal variability of the MIF is predicted to be large at high latitudes. Precise altitude and radar instantaneous line-of-sight (radial) Doppler velocity information are obtained for each of the hundreds of events detected ever day. The results to be discussed include, diurnal meteor rate curves and altitude and radial meteoroid velocity distributions. We compared observed and modeled results and find them to be in good agreement. A surprising result is that the peak of the detected meteor altitude distribution varies up to an atmospheric scale height depending on season. We will discuss if these changes are due to seasonal variability of the atmospheric temperature in the mesosphere or in the directionality of the meteoric influx.

  8. Evaluation of two population-based input functions for quantitative neurological FDG PET studies

    International Nuclear Information System (INIS)

    The conventional measurement of the regional cerebral metabolic rate of glucose (rCMRGlc) with fluorodexoyglucose (FDG) and positron emission tomography (PET) requires arterial or arterialised-venous (a-v) blood sampling at frequent intervals to obtain the plasma input function (IF). We evaluated the accuracy of rCMRGlc measurements using population-based IFs that were calibrated with two a-v blood samples. Population-based IFs were derived from: (1) the average of a-v IFs from 26 patients (Standard IF) and (2) a published model of FDG plasma concentration (Feng IF). Values for rCMRGlc calculated from the population-based IFs were compared with values obtained with IFs derived from frequent a-v blood sampling in 20 non-diabetic and six diabetic patients. Values for rCMRGlc calculated with the different IFs were highly correlated for both patient groups (r≥0.992) and root mean square residuals about the regression line were less than 0.24 mg/min/100 g. The Feng IF tended to underestimate high rCMRGlc. Both population-based IFs simplify the measurement of rCMRGlc with minimal loss in accuracy and require only two a-v blood samples for calibration. The reduced blood sampling requirements markedly reduce radiation exposure to the blood sampler. (orig.)

  9. Visual input controls the functional activity of goldfish Mauthner neuron through the reciprocal synaptic mechanism.

    Science.gov (United States)

    Moshkov, Dmitry A; Shtanchaev, Rashid S; Mikheeva, Irina B; Bezgina, Elena N; Kokanova, Nadezhda A; Mikhailova, Gulnara Z; Tiras, Nadezhda R; Pavlik, Lyubov' L

    2013-03-01

    Goldfish are known to exhibit motor asymmetry due to functional asymmetry of their Mauthner neurons that induce the turns to the right or left during free swimming. It has been previously found that if the less active neuron is subjected to prolonged aimed visual stimulation via its ventral dendrite, the motor asymmetry of goldfish is inverted, testifying that this neuron becomes functionally dominant, while the size of the ventral dendrite under these conditions is reduced 2-3 times compared to its counterpart in mirror neuron. Earlier it has been also revealed that training optokinetic stimulation induces adaptation, a substantial resistance of both fish motor asymmetry and morphofunctional state of Mauthner neurons against prolonged optokinetic stimulation. The aim of this work was to study the cellular mechanisms of the effect of an unusual visual afferent input on goldfish motor asymmetry and Mauthner neuron function in norm and under adaptation. It was shown that serotonin applied onto Mauthner neurons greatly reduces their activity whereas its antagonist ondansetron increases it. Against the background of visual stimulation, serotonin strengthens functional asymmetry between neurons whereas ondansetron smoothes it. Taken together these data suggest the involvement of serotonergic excitatory synaptic transmission in the regulation of Mauthner neurons by vision. Ultrastructural study of the ventral dendrites after prolonged optokinetic stimulation has revealed depletions of numeral axo-axonal synapses with specific morphology, identified by means of immunogold label as serotonergic ones. These latter in turn are situated mainly on shaft boutons, which according to specific ultrastructural features are assigned to axo-dendritic inhibitory synapses. Thus, the excitatory serotonergic synapses seem to affect Mauthner neuron indirectly through inhibitory synapses. Further, it was morphometrically established that adaptation is accompanied by the significant

  10. Visual input controls the functional activity of goldfish Mauthner neuron through the reciprocal synaptic mechanism.

    Science.gov (United States)

    Moshkov, Dmitry A; Shtanchaev, Rashid S; Mikheeva, Irina B; Bezgina, Elena N; Kokanova, Nadezhda A; Mikhailova, Gulnara Z; Tiras, Nadezhda R; Pavlik, Lyubov' L

    2013-03-01

    Goldfish are known to exhibit motor asymmetry due to functional asymmetry of their Mauthner neurons that induce the turns to the right or left during free swimming. It has been previously found that if the less active neuron is subjected to prolonged aimed visual stimulation via its ventral dendrite, the motor asymmetry of goldfish is inverted, testifying that this neuron becomes functionally dominant, while the size of the ventral dendrite under these conditions is reduced 2-3 times compared to its counterpart in mirror neuron. Earlier it has been also revealed that training optokinetic stimulation induces adaptation, a substantial resistance of both fish motor asymmetry and morphofunctional state of Mauthner neurons against prolonged optokinetic stimulation. The aim of this work was to study the cellular mechanisms of the effect of an unusual visual afferent input on goldfish motor asymmetry and Mauthner neuron function in norm and under adaptation. It was shown that serotonin applied onto Mauthner neurons greatly reduces their activity whereas its antagonist ondansetron increases it. Against the background of visual stimulation, serotonin strengthens functional asymmetry between neurons whereas ondansetron smoothes it. Taken together these data suggest the involvement of serotonergic excitatory synaptic transmission in the regulation of Mauthner neurons by vision. Ultrastructural study of the ventral dendrites after prolonged optokinetic stimulation has revealed depletions of numeral axo-axonal synapses with specific morphology, identified by means of immunogold label as serotonergic ones. These latter in turn are situated mainly on shaft boutons, which according to specific ultrastructural features are assigned to axo-dendritic inhibitory synapses. Thus, the excitatory serotonergic synapses seem to affect Mauthner neuron indirectly through inhibitory synapses. Further, it was morphometrically established that adaptation is accompanied by the significant

  11. Functional identification of the input-output transforms of motoneurones in the rat and cat.

    Science.gov (United States)

    Poliakov, A V; Powers, R K; Binder, M D

    1997-10-15

    associated PSTH. This linear model provided good matches to the PSTHs associated with a wide range of current transients. However, for the largest amplitude current transients, a significant improvement in the PSTH match was often achieved by expanding the model to include the convolution of the second-order Wiener kernel with the input. 4. The overall transformation of current inputs into firing rate could be approximated by a second-order Wiener model, i.e. a cascade of a dynamic, linear filter followed by a static non-linearity. At a given mean firing rate, the non-linear component of the response of the motoneurone could be described by the square of the linear component multiplied by a constant coefficient. The amplitude of the response of the linear component increased with the average firing rate, whereas the value of the multiplicative coefficient in the non-linear component decreased. As a result, the overall transform could be predicted from the mean firing rate and the linear impulse response, yielding a relatively simple, general description of the motoneurone input-output function.

  12. Normalization of aortic function during arousal episodes in the hibernating ground squirrel

    OpenAIRE

    Henning, RH; Deelman, LE; Hut, RA; Van der Zee, EA; Buikema, H; Nelemans, SA; Lip, H.; de Zeeuw, D; Daan, S.; Epema, AH; Epema, Anne H.

    2002-01-01

    Hypothermia is commonly used to restrict organ damage during preservation of tissue, but does not offer complete protection. Organ damage after reperfusion/rewarming is amongst others caused by an impairment of vascular properties, particularly endothelium-dependent vasodilatation. We hypothesized that hibernating small animals, which frequently cycle through periods of deep cooling (torpor) and full rewarming (arousal), employ specific mechanisms to preserve vascular function after cooling a...

  13. When and how to replace the aortic root in type A aortic dissection.

    Science.gov (United States)

    Leshnower, Bradley G; Chen, Edward P

    2016-07-01

    Management of aortic root pathology during repair of acute type A aortic dissection (TAAD) requires a comprehensive evaluation of the patient's anatomy, demographics, comorbidities and physiologic status at the time of emergent operative intervention. Surgical options include conservative repair of the root (CRR) (with or without replacement of the aortic valve), replacement of the native valve and aortic root using a composite valve-conduit and valve sparing root replacement (VSRR). The primary objective of this review is to provide data for surgeons to aid in their decision-making process regarding management of the aortic root during repair of TAAD. No time or language restrictions were imposed and references of the selected studies were checked for additional relevant citations. Multiple retrospective reviews have demonstrated equivalent operative mortality between aortic root repair and replacement during TAAD. There is a higher incidence of aortic root reintervention with aortic root repair compared to aortic root replacement (ARR). Experienced, high-volume aortic centers have demonstrated the safety of VSRR in young, hemodynamically stable patients presenting with TAAD. In conclusion, aortic root repair can safely be performed in the vast majority of patients with TAAD. Despite the increased surgical complexity, ARR does not increase operative mortality and improves the freedom from root reintervention. VSRR can be performed in highly selected populations of patients with TAAD with durable mid-term valve function. PMID:27563551

  14. A new procedure for automatic fitting of the basilar-membrane input-output function to individual behavioral data

    DEFF Research Database (Denmark)

    Kowalewski, Borys; Fereczkowski, Michal; MacDonald, Ewen;

    2016-01-01

    The basilar membrane input-output function (BM I/O) in a healthy cochlea is highly nonlinear. One of the consequences of sensorineural hearing loss (SNHL) is a partial or full loss of this nonlinearity. Behavioral estimates of the individual BM I/O can be useful for modeling the impaired auditory...... parameters is difficult. Until recently, the parameters were manually adjusted and the fitting process was indirect. A new approach is described here, based on a search through a lookup table of pre-computed filterbank input-output functions. The aim of this approach is to provide a fast, stable, and more...

  15. Metformin improves endothelial function in aortic tissue and microvascular endothelial cells subjected to diabetic hyperglycaemic conditions.

    Science.gov (United States)

    Ghosh, Suparna; Lakshmanan, Arun P; Hwang, Mu Ji; Kubba, Haidar; Mushannen, Ahmed; Triggle, Chris R; Ding, Hong

    2015-12-01

    The cellular mechanisms whereby metformin, the first line drug for type 2 diabetes (T2DM), mediates its antidiabetic effects remain elusive, particularly as to whether metformin has a direct protective action on the vasculature. This study was designed to determine if a brief 3-h exposure to metformin protects endothelial function against the effects of hyperglycaemia. We investigated the protective effects of metformin on endothelial-dependent vasodilatation (EDV) in thoracic aortae from T2DM db/db mice and on high glucose (HG, 40 mM) induced changes in endothelial nitric oxide synthase (eNOS) signaling in mouse microvascular endothelial cells (MMECs) in culture. Exposure of aortae from db+/? non-diabetic control mice to high glucose (HG, 40 mM) containing Krebs for 3-h significantly (Pmetformin; metformin also improved ACh-induced EDV in aortae from diabetic db/db mice. Immunoblot analysis of MMECs cultured in HG versus NG revealed a significant reduction of the ratio of phosphorylated (p-eNOS)/eNOS and p-Akt/Akt, but not the expression of total eNOS or Akt. The 3-h exposure of MMECs to metformin significantly (Pmetformin can reverse/reduce the impact of HG on endothelial function, via mechanisms linked to increased phosphorylation of eNOS and Akt.

  16. Plasma input function determination for PET using a commercial laboratory robot

    International Nuclear Information System (INIS)

    A commercial laboratory robot system (Zymate PyTechnology II Laboratory Automation System) was interfaced to standard and custom laboratory equipment and programmed to perform rapid radiochemical assays necessary for plasma input function determination in quantitative PET studies in humans and baboons. A Zymark XP robot arm was used to carry out two assays: (1) the determination of total plasma radioactivity concentrations in a series of small-volume whole blood samples and (2) the determination of unchanged (parent) radiotracer in plasma using only solid phase extraction methods. Steady state robotic throughput for determination of total plasma radioactivity in whole blood samples (0.350 mL) is 14.3 samples/h, which includes automated centrifugation, pipetting, weighing and radioactivity counting. Robotic throughput for the assay of parent radiotracer in plasma is 4-6 samples/h depending on the radiotracer. Percents of total radioactivities present as parent radiotracers at 60 min. postinjection of 25 ± 5.0 (N 25), 26 ± 6.8 (N = 68), 13 ± 4.4 (N = 30), 32 ± 7.2 (N = 18), 16 ± 4.9 (N = 20), were obtained for carbon-11 labeled benztropine, raclopride, methylphenidate, SR 46349B (trans, 4-[(3Z)3-(2-dimethylamino-ethyl) oxyimino-3 (2-fluorophenyl)propen-1-yl]phenol), and cocaine respectively in baboon plasma and 84 ± 6.4 (N = 9), 18 ± 11 (N = 10), 74 ± 5.7 (N = 118) and 16 ± 3.7 (N = 18) for carbon-11 labeled benztropine, deprenyl, raclopride, and methylphenidate respectively in human plasma. The automated system has been used for more than 4 years for all plasma analyses for 7 different C-11 labeled compounds used routinely in our laboratory. The robotic radiotracer assay runs unattended and includes automated cleanup procedures that eliminates all human contact with plasma-contaminated containers

  17. Plasma input function determination for PET using a commercial laboratory robot

    Energy Technology Data Exchange (ETDEWEB)

    Alexoff, David L.; Shea, Colleen; Fowler, Joanna S.; King, Payton; Gatley, S. John; Schlyer, David J.; Wolf, Alfred P

    1995-10-01

    A commercial laboratory robot system (Zymate PyTechnology II Laboratory Automation System) was interfaced to standard and custom laboratory equipment and programmed to perform rapid radiochemical assays necessary for plasma input function determination in quantitative PET studies in humans and baboons. A Zymark XP robot arm was used to carry out two assays: (1) the determination of total plasma radioactivity concentrations in a series of small-volume whole blood samples and (2) the determination of unchanged (parent) radiotracer in plasma using only solid phase extraction methods. Steady state robotic throughput for determination of total plasma radioactivity in whole blood samples (0.350 mL) is 14.3 samples/h, which includes automated centrifugation, pipetting, weighing and radioactivity counting. Robotic throughput for the assay of parent radiotracer in plasma is 4-6 samples/h depending on the radiotracer. Percents of total radioactivities present as parent radiotracers at 60 min. postinjection of 25 {+-} 5.0 (N 25), 26 {+-} 6.8 (N = 68), 13 {+-} 4.4 (N = 30), 32 {+-} 7.2 (N = 18), 16 {+-} 4.9 (N = 20), were obtained for carbon-11 labeled benztropine, raclopride, methylphenidate, SR 46349B (trans, 4-[(3Z)3-(2-dimethylamino-ethyl) oxyimino-3 (2-fluorophenyl)propen-1-yl]phenol), and cocaine respectively in baboon plasma and 84 {+-} 6.4 (N = 9), 18 {+-} 11 (N = 10), 74 {+-} 5.7 (N = 118) and 16 {+-} 3.7 (N = 18) for carbon-11 labeled benztropine, deprenyl, raclopride, and methylphenidate respectively in human plasma. The automated system has been used for more than 4 years for all plasma analyses for 7 different C-11 labeled compounds used routinely in our laboratory. The robotic radiotracer assay runs unattended and includes automated cleanup procedures that eliminates all human contact with plasma-contaminated containers.

  18. Altered diastolic function and aortic stiffness in Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Çalık AN

    2014-07-01

    Full Text Available Ali Nazmi Çalik,3 Kazim Serhan Özcan,4 Gülbün Yüksel,2 Baris Güngör,1 Emre Arugarslan,1 Figen Varlibas,2 Ahmet Ekmekci,1 Damirbek Osmonov,1 Mustafa Adem Tatlisu,1 Mehmet Karaca,1 Osman Bolca,1 Izzet Erdinler1 1Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey; 2Department of Neurology, Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey; 3Department of Cardiology, Yozgat State Hospital, Yozgat, Turkey; 4Department of Cardiology, Derince Training and Research Hospital, Kocaeli, Turkey Background: Alzheimer’s disease (AD is closely linked to cardiovascular risk factors.Methods: Echocardiographic studies were performed, including left ventricular diastolic functions, left and right atrial conduction times, and arterial stiffness parameters, namely stiffness index, pressure-strain elastic modulus, and distensibility, on 29 patients with AD and 24 age-matched individuals with normal cognitive function.Results: The peak mitral flow velocity of the early rapid filling wave (E was lower, and the peak velocity of the late filling wave caused by atrial contraction (A, deceleration time of peak E velocity, and isovolumetric relaxation time were higher in the AD group. The early myocardial peak (Ea velocity was significantly lower in AD patients, whereas the late diastolic (Aa velocity and E/Ea ratio were similar between the two groups. In Alzheimer patients, stiffness index and pressure-strain elastic modulus were higher, and distensibility was significantly lower in the AD group compared to the control. Interatrial electromechanical delay was significantly longer in the AD group.Conclusion: Our findings suggest that patients with AD are more likely to have diastolic dysfunction, higher atrial conduction times, and increased arterial stiffness compared to the controls of same sex and similar age. Keywords: diastolic dysfunction, atrial conduction timeA Letter to the Editor has been

  19. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik;

    2013-01-01

    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  20. Effect of dynamic keyboard and word-prediction systems on text input speed in persons with functional tetraplegia

    Directory of Open Access Journals (Sweden)

    Samuel Pouplin, OT, MSc

    2014-06-01

    Full Text Available Information technology plays a very important role in society. People with disabilities are often limited by slow text input speed despite the use of assistive devices. This study aimed to evaluate the effect of a dynamic on-screen keyboard (Custom Virtual Keyboard and a word-prediction system (Sibylle on text input speed in participants with functional tetraplegia. Ten participants tested four modes at home (static on-screen keyboard with and without word prediction and dynamic on-screen keyboard with and without word prediction for 1 mo before choosing one mode and then using it for another month. Initial mean text input speed was around 23 characters per minute with the static keyboard and 12 characters per minute with the dynamic keyboard. The results showed that the dynamic keyboard reduced text input speed by 37% compared with the standard keyboard and that the addition of word prediction had no effect on text input speed. We suggest that current forms of dynamic keyboards and word prediction may not be suitable for increasing text input speed, particularly for subjects who use pointing devices. Future studies should evaluate the optimal ergonomic design of dynamic keyboards and the number and position of words that should be predicted.

  1. Beating Heart Mitral Valve Replacement Surgery without Aortic Cross-Clamping via Right Thoracotomy in a Patient with Compromised Left Ventricular Functions

    Directory of Open Access Journals (Sweden)

    Ahmet Baris-Durukan

    2015-10-01

    Full Text Available Global myocardial ischemia and ischemia-reperfusion injury are potential adverse events related with cardioplegic arrest. Beating heart surgery has avoided such complications and adapted to valve surgery following successful results published on myocardial revascularization. Difficulty in weaning from cardiopulmonary bypass may be lessened by using on-pump beating heart surgery for mitral valve interventions. Here we describe a 64-year-old male patient with severe mitral regurgitation and dilated cardiomyopathy. Beating heart mitral valve replacement surgery was performed without aortic cross-clamping through a right thoracotomy approach. We believe that, particularly in patients with poor left ventricular functions, beating heart mitral valve surgery may be advantageous

  2. Feasibility study of the non-invasive estimation of the β+ arterial input function for human PET imaging

    International Nuclear Information System (INIS)

    This work deals with the estimation of the concentration of molecules in arterial blood which are labelled with positron-emitting radioelements. This concentration is called 'β+ arterial input function'. This concentration has to be estimated for a large number of pharmacokinetic analyses. Nowadays it is measured through series of arterial sampling, which is an accurate method but requiring a stringent protocol. Complications might occur during arterial blood sampling because this method is invasive (hematomas, nosocomial infections). The objective of this work is to overcome this risk through a non-invasive estimation of β+ input function with an external detector and a collimator. This allows the reconstruction of blood vessels and thus the discrimination of arterial signal from signals in other tissues. Collimators in medical imaging are not adapted to estimate β+ input function because their sensitivity is very low. During this work, they are replaced by coded-aperture collimators, originally developed for astronomy. New methods where coded apertures are used with statistical reconstruction algorithms are presented. Techniques for analytical ray-tracing and for the acceleration of reconstructions are proposed. A new method which decomposes reconstructions on temporal sets and on spatial sets is also developed to efficiently estimate arterial input function from series of temporal acquisitions. This work demonstrates that the trade-off between sensitivity and spatial resolution in PET can be improved thanks to coded aperture collimators and statistical reconstruction algorithm; it also provides new tools to implement such improvements. (author)

  3. Ranking Hearing Aid Input-Output Functions for Understanding Low-, Conversational-, and High-Level Speech in Multitalker Babble

    Science.gov (United States)

    Chung, King; Killion, Mead C.; Christensen, Laurel A.

    2007-01-01

    Purpose: To determine the rankings of 6 input-output functions for understanding low-level, conversational, and high-level speech in multitalker babble without manipulating volume control for listeners with normal hearing, flat sensorineural hearing loss, and mildly sloping sensorineural hearing loss. Method: Peak clipping, compression limiting,…

  4. Arterial Input Function Placement for Accurate CT Perfusion Map Construction in Acute Stroke

    Science.gov (United States)

    Ferreira, Rafael M.; Lev, Michael H.; Goldmakher, Gregory V.; Kamalian, Shahmir; Schaefer, Pamela W.; Furie, Karen L.; Gonzalez, R. Gilberto; Sanelli, Pina C.

    2013-01-01

    OBJECTIVE The objective of our study was to evaluate the effect of varying arterial input function (AIF) placement on the qualitative and quantitative CT perfusion parameters. MATERIALS AND METHODS Retrospective analysis of CT perfusion data was performed on 14 acute stroke patients with a proximal middle cerebral artery (MCA) clot. Cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps were constructed using a systematic method by varying only the AIF placement in four positions relative to the MCA clot including proximal and distal to the clot in the ipsilateral and contralateral hemispheres. Two postprocessing software programs were used to evaluate the effect of AIF placement on perfusion parameters using a delay-insensitive deconvolution method compared with a standard deconvolution method. RESULTS One hundred sixty-eight CT perfusion maps were constructed for each software package. Both software programs generated a mean CBF at the infarct core of < 12 mL/100 g/min and a mean CBV of < 2 mL/100 g for AIF placement proximal to the clot in the ipsilateral hemisphere and proximal and distal to the clot in the contralateral hemisphere. For AIF placement distal to the clot in the ipsilateral hemisphere, the mean CBF significantly increased to 17.3 mL/100 g/min with delay-insensitive software and to 19.4 mL/100 g/min with standard software (p < 0.05). The mean MTT was significantly decreased for this AIF position. Furthermore, this AIF position yielded qualitatively different parametric maps, being most pronounced with MTT and CBF. Overall, CBV was least affected by AIF location. CONCLUSION For postprocessing of accurate quantitative CT perfusion maps, laterality of the AIF location is less important than avoiding AIF placement distal to the clot as detected on CT angiography. This pitfall is less severe with deconvolution-based software programs using a delay-insensitive technique than with those using a standard deconvolution

  5. Relative sensitivities of DCE-MRI pharmacokinetic parameters to arterial input function (AIF) scaling.

    Science.gov (United States)

    Li, Xin; Cai, Yu; Moloney, Brendan; Chen, Yiyi; Huang, Wei; Woods, Mark; Coakley, Fergus V; Rooney, William D; Garzotto, Mark G; Springer, Charles S

    2016-08-01

    Dynamic-Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) has been used widely for clinical applications. Pharmacokinetic modeling of DCE-MRI data that extracts quantitative contrast reagent/tissue-specific model parameters is the most investigated method. One of the primary challenges in pharmacokinetic analysis of DCE-MRI data is accurate and reliable measurement of the arterial input function (AIF), which is the driving force behind all pharmacokinetics. Because of effects such as inflow and partial volume averaging, AIF measured from individual arteries sometimes require amplitude scaling for better representation of the blood contrast reagent (CR) concentration time-courses. Empirical approaches like blinded AIF estimation or reference tissue AIF derivation can be useful and practical, especially when there is no clearly visible blood vessel within the imaging field-of-view (FOV). Similarly, these approaches generally also require magnitude scaling of the derived AIF time-courses. Since the AIF varies among individuals even with the same CR injection protocol and the perfect scaling factor for reconstructing the ground truth AIF often remains unknown, variations in estimated pharmacokinetic parameters due to varying AIF scaling factors are of special interest. In this work, using simulated and real prostate cancer DCE-MRI data, we examined parameter variations associated with AIF scaling. Our results show that, for both the fast-exchange-limit (FXL) Tofts model and the water exchange sensitized fast-exchange-regime (FXR) model, the commonly fitted CR transfer constant (K(trans)) and the extravascular, extracellular volume fraction (ve) scale nearly proportionally with the AIF, whereas the FXR-specific unidirectional cellular water efflux rate constant, kio, and the CR intravasation rate constant, kep, are both AIF scaling insensitive. This indicates that, for DCE-MRI of prostate cancer and possibly other cancers, kio and kep may be more suitable imaging

  6. Image-derived input function obtained in a 3TMR-brainPET

    Energy Technology Data Exchange (ETDEWEB)

    Silva, N.A. da [Institute of Biophysics and Biomedical Engineering, University of Lisbon (Portugal); Institute of Neurosciences and Medicine - 4, Juelich (Germany); Herzog, H., E-mail: h.herzog@fz-juelich.de [Institute of Neurosciences and Medicine - 4, Juelich (Germany); Weirich, C.; Tellmann, L.; Rota Kops, E. [Institute of Neurosciences and Medicine - 4, Juelich (Germany); Hautzel, H. [Department of Nuclear Medicine (KME), University of Duesseldorf, Medical Faculty at Research Center Juelich, Juelich (Germany); Almeida, P. [Institute of Biophysics and Biomedical Engineering, University of Lisbon (Portugal)

    2013-02-21

    Aim: The combination of a high-resolution MR-compatible BrainPET insert operated within a 3 T MAGNETOM Trio MR scanner is an excellent tool for obtaining an image derived input function (IDIF), due to simultaneous imaging. In this work, we explore the possibility of obtaining an IDIF from volumes of interest (VOI) defined over the carotid arteries (CAs) using the MR data. Material and methods: FDG data from three patients without brain disorders were included. VOIs were drawn bilaterally over the CAs on a MPRAGE image using a 50% isocontour (MR50VOI). CA PET/MR co-registration was examined based on an individual and combined CA co-registration. After that, to estimate the IDIF, the MR50VOI average (IDIF-A), four hottest pixels per plane (IDIF-4H) and four hottest pixels in VOI (IDIF-4V) were considered. A model-based correction for residual partial volume effects involving venous blood samples was applied, from which partial volume (PV) and spillover (SP) coefficients were estimated. Additionally, a theoretical PV coefficient (PVt) was calculated based on MR50VOI. Results: The results show an excellent co-registration between the MR and PET, with an area under the curve ratio between both co-registration methods of 1.00±0.04. A good agreement between PV and PVt was found for IDIF-A, with PV of 0.39±0.06 and PVt 0.40±0.03, and for IDIF-4H, with PV of 0.47±0.05 and PVt 0.47±0.03. The SPs were 0.20±0.03 and 0.21±0.03 for IDIF-A and IDIF-4H, respectively. Conclusion: The integration of a high resolution BrainPET in an MR scanner allows to obtain an IDIF from an MR-based VOI. This must be corrected for a residual partial volume effect.

  7. Relative sensitivities of DCE-MRI pharmacokinetic parameters to arterial input function (AIF) scaling

    Science.gov (United States)

    Li, Xin; Cai, Yu; Moloney, Brendan; Chen, Yiyi; Huang, Wei; Woods, Mark; Coakley, Fergus V.; Rooney, William D.; Garzotto, Mark G.; Springer, Charles S.

    2016-08-01

    Dynamic-Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) has been used widely for clinical applications. Pharmacokinetic modeling of DCE-MRI data that extracts quantitative contrast reagent/tissue-specific model parameters is the most investigated method. One of the primary challenges in pharmacokinetic analysis of DCE-MRI data is accurate and reliable measurement of the arterial input function (AIF), which is the driving force behind all pharmacokinetics. Because of effects such as inflow and partial volume averaging, AIF measured from individual arteries sometimes require amplitude scaling for better representation of the blood contrast reagent (CR) concentration time-courses. Empirical approaches like blinded AIF estimation or reference tissue AIF derivation can be useful and practical, especially when there is no clearly visible blood vessel within the imaging field-of-view (FOV). Similarly, these approaches generally also require magnitude scaling of the derived AIF time-courses. Since the AIF varies among individuals even with the same CR injection protocol and the perfect scaling factor for reconstructing the ground truth AIF often remains unknown, variations in estimated pharmacokinetic parameters due to varying AIF scaling factors are of special interest. In this work, using simulated and real prostate cancer DCE-MRI data, we examined parameter variations associated with AIF scaling. Our results show that, for both the fast-exchange-limit (FXL) Tofts model and the water exchange sensitized fast-exchange-regime (FXR) model, the commonly fitted CR transfer constant (Ktrans) and the extravascular, extracellular volume fraction (ve) scale nearly proportionally with the AIF, whereas the FXR-specific unidirectional cellular water efflux rate constant, kio, and the CR intravasation rate constant, kep, are both AIF scaling insensitive. This indicates that, for DCE-MRI of prostate cancer and possibly other cancers, kio and kep may be more suitable imaging

  8. Association of Aortic Compliance and Brachial Endothelial Function with Cerebral Small Vessel Disease in Type 2 Diabetes Mellitus Patients: Assessment with High-Resolution MRI.

    Science.gov (United States)

    Shan, Yan; Lin, Jiang; Xu, Pengju; Zeng, Mengsu; Lin, Huandong; Yan, Hongmei

    2016-01-01

    Objective. To assess the possible association of aortic compliance and brachial endothelial function with cerebral small vessel disease in type 2 diabetes mellitus (DM2) patients by using 3.0 T high-resolution magnetic resonance imaging. Methods. Sixty-two clinically confirmed DM2 patients (25 women and 37 men; mean age: 56.8 ± 7.5 years) were prospectively enrolled for noninvasive MR examinations of the aorta, brachial artery, and brain. Aortic arch pulse wave velocity (PWV), flow-mediated dilation (FMD) of brachial artery, lacunar brain infarcts, and periventricular and deep white matter hyperintensities (WMHs) were assessed. Pearson and Spearman correlation analysis were performed to analyze the association between PWV and FMD with clinical data and biochemical test results. Univariable logistic regression analyses were used to analyze the association between PWV and FMD with cerebral small vessel disease. Multiple logistic regression analyses were used to find out the independent predictive factors of cerebral small vessel disease. Results. Mean PWV was 6.73 ± 2.00 m/s and FMD was 16.67 ± 9.11%. After adjustment for compounding factors, PWV was found significantly associated with lacunar brain infarcts (OR = 2.00; 95% CI: 1.14-3.2; P < 0.05) and FMD was significantly associated with periventricular WMHs (OR = 0.82; 95% CI: 0.71-0.95; P < 0.05). Conclusions. Quantitative evaluation of aortic compliance and endothelial function by using high-resolution MRI may be potentially useful to stratify DM2 patients with risk of cerebral small vessel disease. PMID:27525261

  9. Association of Aortic Compliance and Brachial Endothelial Function with Cerebral Small Vessel Disease in Type 2 Diabetes Mellitus Patients: Assessment with High-Resolution MRI

    Science.gov (United States)

    Shan, Yan; Zeng, Mengsu; Lin, Huandong; Yan, Hongmei

    2016-01-01

    Objective. To assess the possible association of aortic compliance and brachial endothelial function with cerebral small vessel disease in type 2 diabetes mellitus (DM2) patients by using 3.0 T high-resolution magnetic resonance imaging. Methods. Sixty-two clinically confirmed DM2 patients (25 women and 37 men; mean age: 56.8 ± 7.5 years) were prospectively enrolled for noninvasive MR examinations of the aorta, brachial artery, and brain. Aortic arch pulse wave velocity (PWV), flow-mediated dilation (FMD) of brachial artery, lacunar brain infarcts, and periventricular and deep white matter hyperintensities (WMHs) were assessed. Pearson and Spearman correlation analysis were performed to analyze the association between PWV and FMD with clinical data and biochemical test results. Univariable logistic regression analyses were used to analyze the association between PWV and FMD with cerebral small vessel disease. Multiple logistic regression analyses were used to find out the independent predictive factors of cerebral small vessel disease. Results. Mean PWV was 6.73 ± 2.00 m/s and FMD was 16.67 ± 9.11%. After adjustment for compounding factors, PWV was found significantly associated with lacunar brain infarcts (OR = 2.00; 95% CI: 1.14–3.2; P < 0.05) and FMD was significantly associated with periventricular WMHs (OR = 0.82; 95% CI: 0.71–0.95; P < 0.05). Conclusions. Quantitative evaluation of aortic compliance and endothelial function by using high-resolution MRI may be potentially useful to stratify DM2 patients with risk of cerebral small vessel disease. PMID:27525261

  10. Specification and Estimation of Production Functions Involving Damage Control Inputs: A Two-Stage, Semiparametric Approach

    NARCIS (Netherlands)

    Kuosmanen, T.K.; Pemsl, D.; Wesseler, J.H.H.

    2006-01-01

    Productivity assessment of damage control inputs (such as pesticides) is complicated because their effect depends on the exposure to damage agents (such as pests). We discuss some open specification and estimation issues. The contribution is threefold. First, we elaborate the separability conditions

  11. Aortic valve and ascending aortic root modeling from 3D and 3D+t CT

    Science.gov (United States)

    Grbic, Saša; Ionasec, Razvan I.; Zäuner, Dominik; Zheng, Yefeng; Georgescu, Bogdan; Comaniciu, Dorin

    2010-02-01

    Aortic valve disorders are the most frequent form of valvular heart disorders (VHD) affecting nearly 3% of the global population. A large fraction among them are aortic root diseases, such as aortic root aneurysm, often requiring surgical procedures (valve-sparing) as a treatment. Visual non-invasive assessment techniques could assist during pre-selection of adequate patients, planning procedures and afterward evaluation of the same. However state of the art approaches try to model a rather short part of the aortic root, insufficient to assist the physician during intervention planning. In this paper we propose a novel approach for morphological and functional quantification of both the aortic valve and the ascending aortic root. A novel physiological shape model is introduced, consisting of the aortic valve root, leaflets and the ascending aortic root. The model parameters are hierarchically estimated using robust and fast learning-based methods. Experiments performed on 63 CT sequences (630 Volumes) and 20 single phase CT volumes demonstrated an accuracy of 1.45mm and an performance of 30 seconds (3D+t) for this approach. To the best of our knowledge this is the first time a complete model of the aortic valve (including leaflets) and the ascending aortic root, estimated from CT, has been proposed.

  12. Sulforaphane Attenuation of Type 2 Diabetes-Induced Aortic Damage Was Associated with the Upregulation of Nrf2 Expression and Function

    Directory of Open Access Journals (Sweden)

    Yonggang Wang

    2014-01-01

    Full Text Available Type 2 diabetes mellitus (T2DM significantly increases risk for vascular complications. Diabetes-induced aorta pathological changes are predominantly attributed to oxidative stress. Nuclear factor E2-related factor-2 (Nrf2 is a transcription factor orchestrating antioxidant and cytoprotective responses to oxidative stress. Sulforaphane protects against oxidative damage by increasing Nrf2 expression and its downstream target genes. Here we explored the protective effect of sulforaphane on T2DM-induced aortic pathogenic changes in C57BL/6J mice which were fed with high-fat diet for 3 months, followed by a treatment with streptozotocin at 100 mg/kg body weight. Diabetic and nondiabetic mice were randomly divided into groups with and without 4-month sulforaphane treatment. Aorta of T2DM mice exhibited significant increases in the wall thickness and structural derangement, along with significant increases in fibrosis (connective tissue growth factor and transforming growth factor, inflammation (tumor necrosis factor-α and vascular cell adhesion molecule 1, oxidative/nitrative stress (3-nitrotyrosine and 4-hydroxy-2-nonenal, apoptosis, and cell proliferation. However, these pathological changes were significantly attenuated by sulforaphane treatment that was associated with a significant upregulation of Nrf2 expression and function. These results suggest that sulforaphane is able to upregulate aortic Nrf2 expression and function and to protect the aorta from T2DM-induced pathological changes.

  13. Accessory Olfactory Bulb Function is Modulated by Input from the Main Olfactory Epithelium

    OpenAIRE

    Slotnick, Burton; Restrepo, Diego; Schellinck, Heather; Archbold, Georgina; Price, Stephen; Lin, Weihong

    2010-01-01

    While it is now established that sensory neurons in both the main olfactory epithelium and the vomeronasal organ may be activated by both general and pheromonal odorants, it remains unclear what initiates sampling by the VNO. Anterograde transport of wheat germ agglutinin-horseradish peroxidase was used to determine that adequate intranasal syringing with zinc sulfate interrupted all inputs to the main olfactory bulb but left intact those to the accessory olfactory bulb. Adult male treated mi...

  14. Transcatheter Versus Surgical Aortic Valve Replacement in Patients With Severe Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Steinbrüchel, Daniel Andreas; Ihlemann, Nikolaj;

    2015-01-01

    BACKGROUND: Transcatheter aortic valve replacement (TAVR) is an option in certain high-risk surgical patients with severe aortic valve stenosis. It is unknown whether TAVR can be safely introduced to lower-risk patients. OBJECTIVES: The NOTION (Nordic Aortic Valve Intervention Trial) randomized...... clinical trial compared TAVR with surgical aortic valve replacement (SAVR) in an all-comers patient cohort. METHODS: Patients ≥ 70 years old with severe aortic valve stenosis and no significant coronary artery disease were randomized 1:1 to TAVR using a self-expanding bioprosthesis versus SAVR. The primary...... conduction abnormalities requiring pacemaker implantation, larger improvement in effective orifice area, more total aortic valve regurgitation, and higher New York Heart Association functional class at 1 year. SAVR-treated patients had more major or life-threatening bleeding, cardiogenic shock, acute kidney...

  15. Aortic Annular Enlargement during Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Selman Dumani

    2016-09-01

    Full Text Available In the surgery of aortic valve replacement is always attempted, as much as possible, to implant the larger prosthesis with the mains goals to enhance the potential benefits, to minimise transvalvular gradient, decrease left ventricular size and avoid the phenomenon of patient-prosthesis mismatch. Implantation of an ideal prosthesis often it is not possible, due to a small aortic annulus. A variety of aortic annulus enlargement techniques is reported to avoid patient-prosthesis mismatch. We present the case that has submitted four three times open heart surgery. We used Manouguian technique to enlarge aortic anulus with excellent results during the fourth time of surgery.

  16. Structure, Function and Input Pathways of Motion-sensitive Visual Interneurons in Drosophila melanogaster

    OpenAIRE

    Schnell, Bettina

    2010-01-01

    Visual motion detection is of major importance for flies as they use the optic flow generated by their self-motion to control their course during flight. This so called optomotor behavior is thought to be controlled by a set of large-field motion-sensitive cells in the optic lobes called lobula plate tangential cells (LPTCs). LPTCs come in different variants and are tuned to different preferred directions. Their responses can be explained by assuming input from an array of local motion detect...

  17. GRUKON - A package of applied computer programs system input and operating procedures of functional modules

    International Nuclear Information System (INIS)

    This manual describes a software package for the production of multigroup neutron cross-sections from evaluated nuclear data files. It presents the information necessary for the implementation of the program's modules in the framework of the execution of the program, including: operating procedures of the program, the data input, the macrocommand language, the assignment of the system's procedures. This report also presents the methodology used in the coding of the individual modules: the rules, the syntax, the method of procedures. The report also presents an example of the application of the data processing module. (author)

  18. Luminous Intensity of an LED as a Function of Input Power

    OpenAIRE

    Sean King

    2008-01-01

    When current passes through a light-emitting diode (LED), the LED emits an incoherent narrow spectrum of light. The relationship between the input power and the light intensity of an LED is studied in this research. Voltage ranging from 2 to 4 Volts was applied to a blue LED. The voltage across the LED, current through the LED and intensity of the light emitted by the LED were measured. For voltages ranging from 2.4 to 3.5 V, light intensity was found to be linearly related to both the curren...

  19. Automatic detection of local arterial input functions through Independent Component Analysis on Dynamic Contrast enhanced Magnetic Resonance Imaging.

    Science.gov (United States)

    Narvaez, Mario; Ruiz-Espana, Silvia; Arana, Estanislao; Moratal, David

    2015-08-01

    Arterial Input Function (AIF) is obtained from perfusion studies as a basic parameter for the calculus of hemodynamic variables used as surrogate markers of the vascular status of tissues. However, at present, its identification is made manually leading to high subjectivity, low repeatability and considerable time consumption. We propose an alternative method to automatically identify local AIF in perfusion images using Independent Component Analysis. PMID:26737244

  20. c-Myc Alters Substrate Utilization and O-GlcNAc Protein Posttranslational Modifications without Altering Cardiac Function during Early Aortic Constriction.

    Directory of Open Access Journals (Sweden)

    Dolena Ledee

    Full Text Available Hypertrophic stimuli cause transcription of the proto-oncogene c-Myc (Myc. Prior work showed that myocardial knockout of c-Myc (Myc attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we assessed the interplay between Myc, substrate oxidation and cardiac function during early pressure overload hypertrophy. Mice with cardiac specific, inducible Myc knockout (MycKO-TAC and non-transgenic littermates (Cont-TAC were subjected to transverse aortic constriction (TAC; n = 7/group. Additional groups underwent sham surgery (Cont-Sham and MycKO-Sham, n = 5 per group. After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. In sham hearts, Myc knockout did not affect cardiac function or substrate preferences for the citric acid cycle. However, Myc knockout altered fractional contributions during TAC. The unlabeled fractional contribution increased in MycKO-TAC versus Cont-TAC, whereas ketone and free fatty acid fractional contributions decreased. Additionally, protein posttranslational modifications by O-GlcNAc were significantly greater in Cont-TAC versus both Cont-Sham and MycKO-TAC. In conclusion, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy, which may regulate Myc-induced metabolic changes.

  1. Organ protection during aortic cross-clamping.

    Science.gov (United States)

    Yeung, Kak Khee; Groeneveld, Menno; Lu, Joyce Ja-Ning; van Diemen, Pepijn; Jongkind, Vincent; Wisselink, Willem

    2016-09-01

    Open surgical repair of an aortic aneurysm requires aortic cross-clamping, resulting in temporary ischemia of all organs and tissues supplied by the aorta distal to the clamp. Major complications of open aneurysm repair due to aortic cross-clamping include renal ischemia-reperfusion injury and postoperative colonic ischemia in case of supra- and infrarenal aortic aneurysm repair. Ischemia-reperfusion injury results in excessive production of reactive oxygen species and in oxidative stress, which can lead to multiple organ failure. Several perioperative protective strategies have been suggested to preserve renal function during aortic cross-clamping, such as pharmacotherapy and therapeutic hypothermia of the kidneys. In this chapter, we will briefly discuss the pathophysiology of ischemia-reperfusion injury and the preventative measures that can be taken to avoid abdominal organ injury. Finally, techniques to minimize the risk of complications during and after open aneurysm repair will be presented. PMID:27650341

  2. Diffuse Supravalvular Aortic Stenosis: Surgical Repair in Adulthood

    Directory of Open Access Journals (Sweden)

    Giovanni Ferlan

    2009-01-01

    Full Text Available We present the case of a 54-year-old woman in which a diffuse congenital supravalvular aortic stenosis (SVAS was associated with a severe aortic valve incompetence and heavy calcification of the aortic annulus. Repair consisted in resection of the ascending aorta, patch augmentation of the hypoplastic aortic root and annulus, placement of a 20 mm Dacron tubular graft (Vascutek, Renfrewshire, UK and aortic valve replacement with a mechanical prosthesis (Sorin, Turin, Italy. Follow-up echocardiography demonstrated normal prosthetic valve function and a postoperative three-dimensional computed tomographic scan showed a normal shape of the reconstructed ascending aorta.

  3. Aortic Aneurysm Statistics

    Science.gov (United States)

    ... connective tissue disorders, such as Marfan syndrome and Ehlers-Danlos syndrome, get thoracic aortic aneurysms. Signs and symptoms of thoracic aortic aneurysm can include Sharp, sudden pain in the chest or upper back. Shortness of ...

  4. Aortic aneurysm repair - endovascular

    Science.gov (United States)

    EVAR; Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... Endovascular aortic repair is done because your aneurysm is very large, growing quickly, or is leaking or bleeding. You may have ...

  5. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... to become you to our live webcast. Today we’re going to repair an abdominal aortic aneurysm ... and together as a team of multidisciplinary physicians, we’re going to repair an abdominal aortic aneurysm ...

  6. Aortic growth rates in chronic aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, A.M. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States)]. E-mail: ainekell@med.umich.edu; Quint, L.E. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States); Nan, B. [School of Public Health, University of Michigan, Ann Arbor, Michigan (United States); Zheng, J. [School of Public Health, University of Michigan, Ann Arbor, Michigan (United States); Cronin, P. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States); Deeb, G.M. [Division of Cardiac Surgery, University of Michigan Medical Center (United States); Williams, D.M. [Division of Vascular Interventional Imaging, University of Michigan Medical Center (United States)

    2007-09-15

    Aim: To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft. Methods and materials: Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1-123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery. Results: For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications. Conclusions: In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A)

  7. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies.

    Science.gov (United States)

    Xiong, Guoming; Paul, Cumming; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [(18)F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach. PMID:23160517

  8. Latitudinal and seasonal variability of the micrometeor input function: A study using model predictions and observations from Arecibo and PFISR

    Science.gov (United States)

    Fentzke, J. T.; Janches, D.; Sparks, J. J.

    2009-05-01

    In this work, we use a semi-empirical model of the micrometeor input function (MIF) together with meteor head-echo observations obtained with two high power and large aperture (HPLA) radars, the 430 MHz Arecibo Observatory (AO) radar in Puerto Rico (18°N, 67°W) and the 450 MHz Poker flat incoherent scatter radar (PFISR) in Alaska (65°N, 147°W), to study the seasonal and geographical dependence of the meteoric flux in the upper atmosphere. The model, recently developed by Janches et al. [2006a. Modeling the global micrometeor input function in the upper atmosphere observed by high power and large aperture radars. Journal of Geophysical Research 111] and Fentzke and Janches [2008. A semi-empirical model of the contribution from sporadic meteoroid sources on the meteor input function observed at arecibo. Journal of Geophysical Research (Space Physics) 113 (A03304)], includes an initial mass flux that is provided by the six known meteor sources (i.e. orbital families of dust) as well as detailed modeling of meteoroid atmospheric entry and ablation physics. In addition, we use a simple ionization model to treat radar sensitivity issues by defining minimum electron volume density production thresholds required in the meteor head-echo plasma for detection. This simplified approach works well because we use observations from two radars with similar frequencies, but different sensitivities and locations. This methodology allows us to explore the initial input of particles and how it manifests in different parts of the MLT as observed by these instruments without the need to invoke more sophisticated plasma models, which are under current development. The comparisons between model predictions and radar observations show excellent agreement between diurnal, seasonal, and latitudinal variability of the detected meteor rate and radial velocity distributions, allowing us to understand how individual meteoroid populations contribute to the overall flux at a particular

  9. Evaluating input device usability as a function of task difficulty in a tracking task.

    Science.gov (United States)

    Rupp, Michael A; Oppold, Paul; McConnell, Daniel S

    2015-01-01

    Game controllers are emerging as a preferred choice for the manual control of unmanned vehicles, but an understanding of their usability characteristics has yet to emerge. We compared the usability of an Xbox 360 game controller in a dual task situation using MATB II to the traditional joystick and keyboard interface in two experiments. In the first experiment, performance with the game controller was associated with fewer tracking errors. In a second experiment, we trained users on the devices, and found that even after training the game controller was still associated with fewer tracking errors as well as higher usability and lower workload ratings. These results are consistent with the idea that game controllers are highly usable input devices and do not require high mental workload to operate, thus making them suitable for complex control tasks.

  10. Generalized Cobb-Douglas Function for Two Inputs and Linear Elasticity

    Directory of Open Access Journals (Sweden)

    Catalin Angelo Ioan

    2014-12-01

    Full Text Available The article deals with a production function of two factors with constant scale return where the elasticity of one of the factors is a function of first degree. After the examination of parameters conditions according to the axioms of the production functions, there are computed the main indicators. Also, the combination of factors is determined in order to maximize the total output under a given cost.

  11. Modulation of the input-output function by GABAA receptor-mediated currents in rat oculomotor nucleus motoneurons.

    Science.gov (United States)

    Torres-Torrelo, Julio; Torres, Blas; Carrascal, Livia

    2014-11-15

    The neuronal input-output function depends on recruitment threshold and gain of the firing frequency-current (f-I) relationship. These two parameters are positively correlated in ocular motoneurons (MNs) recorded in alert preparation and inhibitory inputs could contribute to this correlation. Phasic inhibition mediated by γ-amino butyric acid (GABA) occurs when a high concentration of GABA at the synaptic cleft activates postsynaptic GABAA receptors, allowing neuronal information transfer. In some neuronal populations, low concentrations of GABA activate non-synaptic GABAA receptors and generate a tonic inhibition, which modulates cell excitability. This study determined how ambient GABA concentrations modulate the input-output relationship of rat oculomotor nucleus MNs. Superfusion of brain slices with GABA (100 μm) produced a GABAA receptor-mediated current that reduced the input resistance, increased the recruitment threshold and shifted the f-I relationship rightward without any change in gain. These modifications did not depend on MN size. In absence of exogenous GABA, gabazine (20 μm; antagonist of GABAA receptors) abolished spontaneous inhibitory postsynaptic currents and revealed a tonic current in MNs. Gabazine increased input resistance and decreased recruitment threshold mainly in larger MNs. The f-I relationship shifted to the left, without any change in gain. Gabazine effects were chiefly due to MN tonic inhibition because tonic current amplitude was five-fold greater than phasic. This study demonstrates a tonic inhibition in ocular MNs that modulates cell excitability depending on cell size. We suggest that GABAA tonic inhibition acting concurrently with glutamate receptors activation could reproduce the positive covariation between threshold and gain reported in alert preparation.

  12. Activity and function recognition for moving and static objects in urban environments from wide-area persistent surveillance inputs

    Science.gov (United States)

    Levchuk, Georgiy; Bobick, Aaron; Jones, Eric

    2010-04-01

    In this paper, we describe results from experimental analysis of a model designed to recognize activities and functions of moving and static objects from low-resolution wide-area video inputs. Our model is based on representing the activities and functions using three variables: (i) time; (ii) space; and (iii) structures. The activity and function recognition is achieved by imposing lexical, syntactic, and semantic constraints on the lower-level event sequences. In the reported research, we have evaluated the utility and sensitivity of several algorithms derived from natural language processing and pattern recognition domains. We achieved high recognition accuracy for a wide range of activity and function types in the experiments using Electro-Optical (EO) imagery collected by Wide Area Airborne Surveillance (WAAS) platform.

  13. Measuring inputs to a common function: The case of Dlx5 and Dlx6.

    Science.gov (United States)

    Quach, Anna; MacKenzie, Rachel K; Bendall, Andrew J

    2016-09-01

    Physically linked Dlx5 and Dlx6 paralogs are co-expressed in vertebrates and various combinations of null alleles in mice demonstrate not only functional redundancy between the paralogous factors but a similar quantitative contribution to craniofacial functions during development. While it is not possible to rule out that the bigene pair contributes some paralog-specific functions it is clear that, for many functions in the head, Dlx5 and Dlx6 are interchangeable. To assess the relative quantitative contribution made by each paralog to bigene function, we have made comparisons of the expression of Dlx5 and Dlx6 in chick embryos and quantitated the transcriptional properties of the encoded proteins in a variety of regulatory and cellular contexts. Our data indicate that the transcriptional activities of both Dlx5 and Dlx6 are very much context dependent; isolated domains fused to a heterologous DNA binding domain have little intrinsic activity, while individual domains are more active when contiguous with their own homeodomain. We find Dlx5 and Dlx6 to be quantitatively indistinguishable on a variety of natural cis-regulatory sequences in a heterologous cellular context but observed quantitatively different transcriptional outputs in cells that normally express these genes, suggesting differential interactions with co-evolved co-activators. PMID:27416760

  14. AN ACCURATE MODELING OF DELAY AND SLEW METRICS FOR ON-CHIP VLSI RC INTERCONNECTS FOR RAMP INPUTS USING BURR’S DISTRIBUTION FUNCTION

    Directory of Open Access Journals (Sweden)

    Rajib Kar

    2010-09-01

    Full Text Available This work presents an accurate and efficient model to compute the delay and slew metric of on-chip interconnect of high speed CMOS circuits foe ramp input. Our metric assumption is based on the Burr’s Distribution function. The Burr’s distribution is used to characterize the normalized homogeneous portion of the step response. We used the PERI (Probability distribution function Extension for Ramp Inputs technique that extends delay metrics and slew metric for step inputs to the more general and realistic non-step inputs. The accuracy of our models is justified with the results compared with that of SPICE simulations.

  15. Experimental study on aortic remodeling in sinoaortic denervated rats

    Institute of Scientific and Technical Information of China (English)

    MIAO Chao-yu; TAO Xia; GUAN Yun-feng; YANG You-cai; CHU Zheng-xu; SU Ding-feng

    2001-01-01

    Objective: To study the aortic remodeling produced by chronic sinoaortic denervation (SAD) and its time course, and to study the role of humoral factor in the SAD-induced aortic remodeling. Methods: In rats with chronic SAD or sham operation, the aortic structure was measured by computer-assisted image analysis, the aortic function by isolated artery preparation, and angiotensin Ⅱ concentration by radioimmunoassay. Results and Conclusion: The aortic structural remodeling developed progressively at 4, 8, 16 and 32 weeks after SAD. Aortic structural remodeling after SAD expressed mainly as aortic hypertrophy due to SMC growth and collagen accumulation. The aortic contraction elicited by norepinephrine (NE) was progressively increased 8, 16 and 32 weeks after SAD. The aortic relaxation elicited by acetylcholine (ACh) was depressed 8, 16 and 32 weeks after SAD. In addition, in 32-week SAD rats the NE-induced contraction was not increased by endothelial denudation. These indicated that the increased contraction and depressed relaxation after SAD were related to the change of endothelium and/or the change of interaction between endothelium and SMC. In 10-week SAD rats, plasma angiotensin Ⅱ concentration remained unchanged, whereas aortic angiotensin Ⅱ concentration was significantly increased, suggesting that activation of tissue renin-angiotensin system may be involved in SAD-induced aortic remodeling.

  16. The functional upregulation of piriform cortex is associated with cross-modal plasticity in loss of whisker tactile inputs.

    Directory of Open Access Journals (Sweden)

    Bing Ye

    Full Text Available BACKGROUND: Cross-modal plasticity is characterized as the hypersensitivity of remaining modalities after a sensory function is lost in rodents, which ensures their awareness to environmental changes. Cellular and molecular mechanisms underlying cross-modal sensory plasticity remain unclear. We aim to study the role of different types of neurons in cross-modal plasticity. METHODOLOGY/PRINCIPAL FINDINGS: In addition to behavioral tasks in mice, whole-cell recordings at the excitatory and inhibitory neurons, and their two-photon imaging, were conducted in piriform cortex. We produced a mouse model of cross-modal sensory plasticity that olfactory function was upregulated by trimming whiskers to deprive their sensory inputs. In the meantime of olfactory hypersensitivity, pyramidal neurons and excitatory synapses were functionally upregulated, as well as GABAergic cells and inhibitory synapses were downregulated in piriform cortex from the mice of cross-modal sensory plasticity, compared with controls. A crosswire connection between barrel cortex and piriform cortex was established in cross-modal plasticity. CONCLUSION/SIGNIFICANCE: An upregulation of pyramidal neurons and a downregulation of GABAergic neurons strengthen the activities of neuronal networks in piriform cortex, which may be responsible for olfactory hypersensitivity after a loss of whisker tactile input. This finding provides the clues for developing therapeutic strategies to promote sensory recovery and substitution.

  17. Transcutaneous measurement of the arterial input function in positron emission tomography

    International Nuclear Information System (INIS)

    Positron emission tomography (PET) provides a powerful tool in medical research. Biochemical function can be both precisely localized and quantitatively measured. To achieve reliable quantitation it is necessary to know the time course of activity concentration in the arterial blood during the measurement. In this study the arterial blood curve from the brachial artery is compared to the activity measured in the internal carotid artery with a new transcutaneous detector

  18. Functional imaging of the human brainstem during somatosensory input and autonomic output

    Directory of Open Access Journals (Sweden)

    Luke Anthony Henderson

    2013-09-01

    Full Text Available Over the past half a century, many experimental animal investigations have explored the role of various brainstem regions in a variety of conditions. Despite the accumulation of a considerable body of knowledge in primarily anaesthetized preparations, relatively few investigations have explored brainstem function in awake humans. It is important that human brainstem function is explored given that many neurological conditions, from obstructive sleep apnea, chronic pain and hypertension, likely involve significant changes in the processing of information within the brainstem. Recent advances in the collection and processing of magnetic resonance images, has resulted in the possibility of exploring brainstem activity changes in awake healthy individuals and in those with various clinical conditions. We and others have begun to explore changes in brainstem activity in humans during a number of challenges, including during cutaneous and muscle pain, as well as during challenges that evoke increases in sympathetic activity. More recently we have successfully recorded sympathetic nerve activity concurrently with fMRI of the brainstem, which will allow us, for the first time to explore brainstem sites directly responsible for conditions such as hypertension. Since many conditions will involve changes in brainstem function and structure, defining brainstem changes will likely result in a greater ability to develop more effective treatment regimes.

  19. File list: InP.CDV.10.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.10.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve... endothelial cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.10.AllAg.Aortic_valve_endothelial_cells.bed ...

  20. File list: InP.CDV.20.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.20.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothelia...l cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.20.AllAg.Aortic_valve_endothelial_cells.bed ...

  1. File list: InP.CDV.50.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.50.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothelia...l cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.50.AllAg.Aortic_valve_endothelial_cells.bed ...

  2. File list: InP.CDV.05.AllAg.Aortic_valve_endothelial_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.CDV.05.AllAg.Aortic_valve_endothelial_cells hg19 Input control Cardiovascular Aortic valve endothelia...l cells SRX285598 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.CDV.05.AllAg.Aortic_valve_endothelial_cells.bed ...

  3. Aortic Valve Sparing in Different Aortic Valve and Aortic Root Conditions.

    Science.gov (United States)

    David, Tirone E

    2016-08-01

    The development of aortic valve-sparing operations (reimplantation of the aortic valve and remodeling of the aortic root) expanded the surgical armamentarium for treating patients with aortic root dilation caused by a variety of disorders. Young adults with aortic root aneurysms associated with genetic syndromes are ideal candidates for reimplantation of the aortic valve, and the long-term results have been excellent. Incompetent bicuspid aortic valves with dilated aortic annuli are also satisfactorily treated with the same type of operation. Older patients with ascending aortic aneurysm and aortic insufficiency secondary to dilated sinotubular junction and a normal aortic annulus can be treated with remodeling of the aortic root or with reimplantation of the aortic valve. The first procedure is simpler, and both procedures are likely equally effective. As with any heart valve-preserving procedure, patient selection and surgical expertise are keys to successful and durable repairs. PMID:27491910

  4. Prophylactic aortic root surgery in patients with Marfan syndrome : 10 years' experience with a protocol based on body surface area

    NARCIS (Netherlands)

    Aalberts, Jan J. J.; van Tintelen, J. Peter; Hillege, Hans L.; Boonstra, Piet W.; van den Berg, Maarten P.; Waterbolk, T

    2008-01-01

    Background: Current guidelines recommending prophylactic aortic root replacement in Marfan syndrome are based on absolute diameters of the aortic root. However, aortic root diameter is a function of body surface area (BSA). Here, we report our experience with a protocol for prophylactic aortic root

  5. Measurement of output power density from mobile phone as a function of input sound frequency.

    Science.gov (United States)

    Calabrò, Emanuele; Magazù, Salvatore

    2013-01-01

    Measurements of power density emitted by a mobile phone were carried out as a function of the sound frequency transmitted by a sound generator, ranging from 250 to 14000 Hz. Output power density was monitored by means of the selective radiation meter Narda SRM 3000 in spectrum analysis mode, and the octave frequency analysis of each tone used for the experimental design was acquired by the sound level meter Larson Davis LxT Wind. Vodafone providers were used for mobile phone calls with respect to various local base station in Southern-Italy. A relationship between the mobile phone microwaves power density and the sound frequencies transmitted by the sound generator was observed. In particular, microwaves power density level decreases significantly at sound frequency values larger than 4500 Hz. This result can be explained assuming that discontinuous transmission mode of global system for mobile communications is powered not only in silence-mode, but also at frequencies larger than 4500 Hz.

  6. Navigation Technology in Endovascular Aortic Repair

    OpenAIRE

    Manstad-Hulaas, Frode

    2013-01-01

    A number of diseases can affect the aorta, and endovascular (minimally invasive) techniques can be used to treat many of these conditions. During endovascular aortic repair, different instruments, such as catheters (plastic tubes), metal wires and balloons are visualized by X-rays. Intermittent aortic injections of contrast medium improve the depiction of the aorta; however, contrast medium may damage kidney function in some patients, radiation can be harmful and X-ray images are 2- dimension...

  7. Temporal dynamics of hot desert microbial communities reveal structural and functional responses to water input

    Science.gov (United States)

    Armstrong, Alacia; Valverde, Angel; Ramond, Jean-Baptiste; Makhalanyane, Thulani P.; Jansson, Janet K.; Hopkins, David W.; Aspray, Thomas J.; Seely, Mary; Trindade, Marla I.; Cowan, Don A.

    2016-01-01

    The temporal dynamics of desert soil microbial communities are poorly understood. Given the implications for ecosystem functioning under a global change scenario, a better understanding of desert microbial community stability is crucial. Here, we sampled soils in the central Namib Desert on sixteen different occasions over a one-year period. Using Illumina-based amplicon sequencing of the 16S rRNA gene, we found that α-diversity (richness) was more variable at a given sampling date (spatial variability) than over the course of one year (temporal variability). Community composition remained essentially unchanged across the first 10 months, indicating that spatial sampling might be more important than temporal sampling when assessing β-diversity patterns in desert soils. However, a major shift in microbial community composition was found following a single precipitation event. This shift in composition was associated with a rapid increase in CO2 respiration and productivity, supporting the view that desert soil microbial communities respond rapidly to re-wetting and that this response may be the result of both taxon-specific selection and changes in the availability or accessibility of organic substrates. Recovery to quasi pre-disturbance community composition was achieved within one month after rainfall. PMID:27680878

  8. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... opens freely when the heart contracts. On the right, we see a picture of the aortic valve ... the aortic valve because the probe is sitting right behind the aortic valve. Lots of patients on ...

  9. Abdominal Aortic Aneurysms: Treatments

    Science.gov (United States)

    ... access catheters Vertebroplasty Women and vascular disease Women's health Social Media Facebook Twitter ... Abdominal Aortic Aneurysms Interventional Radiologists Treat Abdominal Aneurysms Nonsurgically Interventional radiologists are vascular ...

  10. Impact on Left Ventricular Function and Remodeling and on 1-Year Outcome in Patients With Left Bundle Branch Block After Transcatheter Aortic Valve Implantation.

    Science.gov (United States)

    Carrabba, Nazario; Valenti, Renato; Migliorini, Angela; Marrani, Marco; Cantini, Giulia; Parodi, Guido; Dovellini, Emilio Vincenzo; Antoniucci, David

    2015-07-01

    Conflicting results have been reported about the prognostic impact of left bundle branch block (LBBB) after transcatheter aortic valve implantation (TAVI). The aim of this study was to evaluate the impact of LBBB after TAVI on left ventricular (LV) function and remodeling and on 1-year outcomes. Of 101 TAVI patients, 9 were excluded. All complications were evaluated according to the Valve Academic Research Consortium 2 definition. Of 92 patients, 34 developed LBBB without more advanced myocardial damage or inflammation biomarkers in comparison with patients without LBBB. The only predictor of new LBBB was larger baseline LV end-diastolic volume. LBBB plus advanced atrioventricular block was strongly correlated with permanent pacemaker implantation (p reverse remodeling at 1 year. The development of acute kidney injury and the logistic European System for Cardiac Operative Risk Evaluation score were associated with poor outcomes (all-cause mortality and heart failure) (hazard ratio 6.86, 95% confidence interval 2.51 to 18.74, p <0.0001, and hazard ratio 1.04, 95% confidence interval 1.01 to 1.08, p = 0.021, respectively), but not LBBB. In conclusion, after TAVI, 37% of patients developed new LBBB without more advanced myocardial damage or inflammation biomarkers. LBBB was associated with a higher rate of permanent pacemaker implantation, which negatively affected the recovery of LV systolic function. The development of acute kidney injury, rather than LBBB, increases the 1-year risk for mortality and hospitalization for heart failure. PMID:25937352

  11. Conversion of arterial input functions for dual pharmacokinetic modeling using Gd-DTPA/MRI and 18F-FDG/PET.

    Science.gov (United States)

    Poulin, Eric; Lebel, Réjean; Croteau, Etienne; Blanchette, Marie; Tremblay, Luc; Lecomte, Roger; Bentourkia, M'hamed; Lepage, Martin

    2013-03-01

    Reaching the full potential of magnetic resonance imaging (MRI)-positron emission tomography (PET) dual modality systems requires new methodologies in quantitative image analyses. In this study, methods are proposed to convert an arterial input function (AIF) derived from gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) in MRI, into a (18)F-fluorodeoxyglucose ((18)F-FDG) AIF in PET, and vice versa. The AIFs from both modalities were obtained from manual blood sampling in a F98-Fisher glioblastoma rat model. They were well fitted by a convolution of a rectangular function with a biexponential clearance function. The parameters of the biexponential AIF model were found statistically different between MRI and PET. Pharmacokinetic MRI parameters such as the volume transfer constant (K(trans)), the extravascular-extracellular volume fraction (ν(e)), and the blood volume fraction (ν(p)) calculated with the Gd-DTPA AIF and the Gd-DTPA AIF converted from (18)F-FDG AIF normalized with or without blood sample were not statistically different. Similarly, the tumor metabolic rates of glucose (TMRGlc) calculated with (18) F-FDG AIF and with (18) F-FDG AIF obtained from Gd-DTPA AIF were also found not statistically different. In conclusion, only one accurate AIF would be needed for dual MRI-PET pharmacokinetic modeling in small animal models. PMID:22570280

  12. Investigation of dynamic SPECT measurements of the arterial input function in human subjects using simulation, phantom and human studies

    Science.gov (United States)

    Winant, Celeste D.; Aparici, Carina Mari; Zelnik, Yuval R.; Reutter, Bryan W.; Sitek, Arkadiusz; Bacharach, Stephen L.; Gullberg, Grant T.

    2012-01-01

    Computer simulations, a phantom study and a human study were performed to determine whether a slowly rotating single-photon computed emission tomography (SPECT) system could provide accurate arterial input functions for quantification of myocardial perfusion imaging using kinetic models. The errors induced by data inconsistency associated with imaging with slow camera rotation during tracer injection were evaluated with an approach called SPECT/P (dynamic SPECT from positron emission tomography (PET)) and SPECT/D (dynamic SPECT from database of SPECT phantom projections). SPECT/P simulated SPECT-like dynamic projections using reprojections of reconstructed dynamic 94Tc-methoxyisobutylisonitrile (94Tc-MIBI) PET images acquired in three human subjects (1 min infusion). This approach was used to evaluate the accuracy of estimating myocardial wash-in rate parameters K1 for rotation speeds providing 180° of projection data every 27 or 54 s. Blood input and myocardium tissue time-activity curves (TACs) were estimated using spatiotemporal splines. These were fit to a one-compartment perfusion model to obtain wash-in rate parameters K1. For the second method (SPECT/D), an anthropomorphic cardiac torso phantom was used to create real SPECT dynamic projection data of a tracer distribution derived from 94Tc-MIBI PET scans in the blood pool, myocardium, liver and background. This method introduced attenuation, collimation and scatter into the modeling of dynamic SPECT projections. Both approaches were used to evaluate the accuracy of estimating myocardial wash-in parameters for rotation speeds providing 180° of projection data every 27 and 54 s. Dynamic cardiac SPECT was also performed in a human subject at rest using a hybrid SPECT/CT scanner. Dynamic measurements of 99mTc-tetrofosmin in the myocardium were obtained using an infusion time of 2 min. Blood input, myocardium tissue and liver TACs were estimated using the same spatiotemporal splines. The spatiotemporal maximum

  13. Imaging in aortic dissection

    International Nuclear Information System (INIS)

    Aortic dissection (AD) is a catastrophic aortic disease. Imaging techniques play an invaluable role in the diagnostic evaluation and management of patients with AD. Major signs of AD with different imaging modalities are described in this article with a pertinent discussion on guidelines for the optimized approach of imaging study (13 refs.)

  14. Aortic arch malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kellenberger, Christian J. [University Children' s Hospital, Department of Diagnostic Imaging, Zuerich (Switzerland)

    2010-06-15

    Although anomalies of the aortic arch and its branches are relatively uncommon malformations, they are often associated with congenital heart disease. Isolated lesions may be clinically significant when the airways are compromised by a vascular ring. In this article, the development and imaging appearance of the aortic arch system and its various malformations are reviewed. (orig.)

  15. Multi-modal pharmacokinetic modelling for DCE-MRI: using diffusion weighted imaging to constrain the local arterial input function

    Science.gov (United States)

    Hamy, Valentin; Modat, Marc; Shipley, Rebecca; Dikaios, Nikos; Cleary, Jon; Punwani, Shonit; Ourselin, Sebastien; Atkinson, David; Melbourne, Andrew

    2014-03-01

    The routine acquisition of multi-modal magnetic resonance imaging data in oncology yields the possibility of combined model fitting of traditionally separate models of tissue structure and function. In this work we hypothesise that diffusion weighted imaging data may help constrain the fitting of pharmacokinetic models to dynamic contrast enhanced (DCE) MRI data. Parameters related to tissue perfusion in the intra-voxel incoherent motion (IVIM) modelling of diffusion weighted MRI provide local information on how tissue is likely to perfuse that can be utilised to guide DCE modelling via local modification of the arterial input function (AIF). In this study we investigate, based on multi-parametric head and neck MRI of 8 subjects (4 with head and neck tumours), the benefit of incorporating parameters derived from the IVIM model within the DCE modelling procedure. Although we find the benefit of this procedure to be marginal on the data used in this work, it is conceivable that a technique of this type will be of greater use in a different application.

  16. Partial volume correction of the microPET blood input function using ensemble learning independent component analysis

    International Nuclear Information System (INIS)

    Medical images usually suffer from a partial volume effect (PVE), which may degrade the accuracy of any quantitative information extracted from the images. Our aim was to recreate accurate radioactivity concentration and time-activity curves (TACs) by microPET R4 quantification using ensemble learning independent component analysis (EL-ICA). We designed a digital cardiac phantom for this simulation and in order to evaluate the ability of EL-ICA to correct the PVE, the simulated images were convoluted using a Gaussian function (FWHM = 1-4 mm). The robustness of the proposed method towards noise was investigated by adding statistical noise (SNR = 2-16). During further evaluation, another set of cardiac phantoms were generated from the reconstructed images, and Poisson noise at different levels was added to the sinogram. In real experiments, four rat microPET images and a number of arterial blood samples were obtained; these were used to estimate the metabolic rate of FDG (MRFDG). Input functions estimated using the FastICA method were used for comparison. The results showed that EL-ICA could correct PVE in both the simulated and real cases. After correcting for the PVE, the errors for MRFDG, when estimated by the EL-ICA method, were smaller than those when TACs were directly derived from the PET images and when the FastICA approach was used.

  17. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

    International Nuclear Information System (INIS)

    Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification

  18. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Schuhbaeck, Annika, E-mail: annika.schuhbaeck@uk-erlangen.de [Department of Cardiology, University of Erlangen, Erlangen (Germany); Weingartner, Christina [Department of Cardiology, University of Gießen, Giessen (Germany); Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed [Department of Cardiology, University of Erlangen, Erlangen (Germany); Rixe, Johannes; Nef, Holger [Department of Cardiology, University of Gießen, Giessen (Germany); Schneider, Christian [Department of Radiology, University of Gießen, Giessen (Germany); Lell, Michael; Uder, Michael [Department of Radiology, University of Erlangen, Erlangen (Germany); Ensminger, Stephan [Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr-University Bochum, Bad Oeynhausen (Germany); Feyrer, Richard; Weyand, Michael [Department of Cardiothoracic Surgery, University of Erlangen, Erlangen (Germany); Achenbach, Stephan [Department of Cardiology, University of Erlangen, Erlangen (Germany)

    2015-07-15

    Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification.

  19. Non-invasive estimation of hepatic glucose uptake from [{sup 18}F]FDG PET images using tissue-derived input functions

    Energy Technology Data Exchange (ETDEWEB)

    Kudomi, N.; Jaervisalo, M.J.; Borra, R.; Viljanen, A.; Viljanen, T.; Knuuti, J. [University of Turku, Turku PET Centre, P.O. Box 52, Turku (Finland); Kiss, J.; Savunen, T. [University of Turku, Department of Surgery, Turku (Finland); Iida, H. [National Cardiovascular Center-Research Institute, Department of Investigative Radiology, Advanced Medical Engineering Center, Suita, Osaka (Japan); Nuutila, P. [University of Turku, Turku PET Centre, P.O. Box 52, Turku (Finland); University of Turku, Department of Medicine, Turku (Finland); Iozzo, P. [University of Turku, Turku PET Centre, P.O. Box 52, Turku (Finland); National Research Council, Institute of Clinical Physiology, Pisa (Italy)

    2009-12-15

    The liver is perfused through the portal vein and hepatic artery. Quantification of hepatic glucose uptake (HGU) using PET requires the use of an input function for both the hepatic artery and portal vein. The former can be generally obtained invasively, but blood withdrawal from the portal vein is not practical in humans. The aim of this study was to develop and validate a new technique to obtain quantitative HGU by estimating the input function from PET images. Normal pigs (n = 12) were studied with [{sup 18}F]FDG PET, in which arterial and portal blood time-activity curves (TAC) were determined invasively to serve as reference measurements. The present technique consisted of two characteristics, i.e. using a model input function and simultaneously fitting multiple liver tissue TACs from images by minimizing the residual sum of square between the tissue TACs and fitted curves. The input function was obtained from the parameters determined from the fitting. The HGU values were computed by the estimated and measured input functions and compared between the methods. The estimated input functions were well reproduced. The HGU values, ranging from 0.005 to 0.02 ml/min per ml, were not significantly different between the two methods (r = 0.95, p < 0.001). A Bland-Altman plot demonstrated a small overestimation by the image-derived method with a bias of 0.00052 ml/min per g for HGU. The results presented demonstrate that the input function can be estimated directly from the PET image, supporting the fully non-invasive assessment of liver glucose metabolism in human studies. (orig.)

  20. Early and mid-term outcome in terms of functional and hemodynamic performance of the st. Jude regent 19-mm aortic mechanical prosthesis versus 19-mm carpentier edwards aortic biological prosthesis

    OpenAIRE

    Prifti, Edvin; Bonacchi, Massimo; Ademaj, Fadil; Giunti, Gabriele; Esposito, Giampiero; Baboci, Arben; Bajraktari, Gani; Veshti, Altin; Demiraj, Aurel; Vanini, Vittorio

    2015-01-01

    Background The aim of the present study is to compare the early and mid-term clinical and hemodynamic results of the aortic valve replacement (AVR) with a St Jude Medical Regent 19-mm prosthesis (SJMR-19) versus Carpentied-Edwars bovine pericardial 19-mm valve (CE-19). Methods Between January 2002 and January 2012, 265 patients (Group I) and 58 patients (Group II) with underwent AVR with a SJMR-19 and CE-19 respectively. There were no significant differences between groups regarding the demog...

  1. Incidental necropsy finding of a quadricuspid aortic valve

    NARCIS (Netherlands)

    van Rijswijk, Jan Willem; Willemink, Martin; Kluin, Jolanda; Vink, Aryan

    2015-01-01

    Quadricuspid aortic valve is a rare congenital cardiac malformation often associated with abnormal valve function. In this article, we present a case of quadricuspid aortic valve only diagnosed at the time of post-mortem examination. (C) 2015 Elsevier Inc. All rights reserved.

  2. Optimisation of vascular input and output functions in CT-perfusion imaging using 256(or more)-slice multidetector CT

    Energy Technology Data Exchange (ETDEWEB)

    Niesten, Joris M.; Schaaf, Irene C. van der; Riordan, Alan J.; Jong, Hugo W.A.M. de; Mali, Willem P.T.M.; Velthuis, Birgitta K. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

    2013-05-15

    To evaluate the accuracy and reproducibility of CT-perfusion (CTP) by finding the optimal artery for the arterial input function (AIF) and re-evaluating the necessity of the venous output function (VOF). Forty-four acute ischaemic stroke patients who underwent non-enhanced CT, CTP and CT-angiography using 256-slice multidetector computed tomography (MDCT) were evaluated. The anterior cerebral artery (ACA), middle cerebral artery (MCA), internal carotid artery (ICA) and basilar artery were selected as the AIF. Subsequently the resulting area under the time-enhancement curve of the AIF (AUC{sub AIF}) and quantitative perfusion measurements were analysed by repeated measures ANOVA and subsequently the paired t test. To evaluate reproducibility we examined if the VOF could be deleted by comparing the perfusion measurements using versus not using the VOF (paired t test). The AUC{sub AIF} and perfusion measurements resulting from the different AIFs showed significant group differences (all P < 0.0001). The ICA had the largest AUC{sub AIF} and resulted in the highest mean transient time (MTT) and lowest cerebral blood flow (CBF), whereas the basilar artery showed the lowest cerebral blood volume (CBV). Not using the VOF showed significantly higher CBV and CBF in 66 % of patients on the ipsilateral (P < 0.0001 and P = 0.007, respectively) and contralateral hemisphere (P < 0.0001 and P = 0.019, respectively). Selecting the ICA as the AIF and continuing the use of the VOF would improve the accuracy of CTP. (orig.)

  3. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... as atherosclerosis, high blood pressure, smokers, or a family history of abdominal aortic aneurysms. Today’s patient is ... be screened. In fact, patients who have a family history of aneurysm, men who are smoking over ...

  4. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... wall will actually thin out. And the big risk here is that if this gets too big ... to the aging baby boomers. Next slide. The risk factors for abdominal aortic aneurysms are males over ...

  5. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... atherosclerosis, high blood pressure, smokers, or a family history of abdominal aortic aneurysms. Today’s patient is a ... screened. In fact, patients who have a family history of aneurysm, men who are smoking over the ...

  6. Relation between Fresnel transform of input light field and the two-parameter Radon transform of Wigner function of the field

    Institute of Scientific and Technical Information of China (English)

    Fan Hong-Yi; Hu Li-Yun

    2009-01-01

    This paper proves a new theorem on the relationship between optical field Wigner function's two-parameter Radon transform and optical Fresnel transform of the field, I.e., when an input field ψ(x') propagates through an optical [D (-B) (-C) A] system, the energy density of the output field is equal to the Radon transform of the Wigner function of the input field, where the Radon transform parameters are D, B. It prove this theorem in both spatial-domain and frequency-domain, in the latter case the Radon transform parameters are A, C 7.

  7. [Inflammatory abdominal aortic aneurysm].

    Science.gov (United States)

    Ziaja, K; Sedlak, L; Urbanek, T; Kostyra, J; Ludyga, T

    2000-01-01

    The reported incidence of inflammatory abdominal aortic aneurysm (IAAA) is from 2% to 14% of patients with abdominal aortic aneurysm and the etiology of this disease is still discussed--according to the literature several pathogenic theories have been proposed. From 1992 to 1997 32 patients with IAAA were operated on. The patients were mostly symptomatic--abdominal pain was present in 68.75% cases, back pain in 31.25%, fever in 12.5% and weight loss in 6.25% of the operated patients. In all the patients ultrasound examination was performed, in 4 patients CT and in 3 cases urography. All the patients were operated on and characteristic signs of inflammatory abdominal aortic aneurysm like: thickened aortic wall, perianeurysmal infiltration or retroperitoneal fibrosis with involvement of retroperitoneal structures were found. In all cases surgery was performed using transperitoneal approach; in three cases intraoperatively contiguous abdominal organs were injured, which was connected with their involvement into periaortic inflammation. In 4 cases clamping of the aorta was done at the level of the diaphragmatic hiatus. 3 patients (9.37%) died (one patient with ruptured abdominal aortic aneurysm). Authors present diagnostic procedures and the differences in the surgical tactic, emphasizing the necessity of the surgical therapy in patients with inflammatory abdominal aortic aneurysm.

  8. Ultrasonic delineation of aortic microstructure: The relative contribution of elastin and collagen to aortic elasticity

    Science.gov (United States)

    Marsh, Jon N.; Takiuchi, Shin; Lin, Shiow Jiuan; Lanza, Gregory M.; Wickline, Samuel A.

    2004-05-01

    Aortic elasticity is an important factor in hemodynamic health, and compromised aortic compliance affects not only arterial dynamics but also myocardial function. A variety of pathologic processes (e.g., diabetes, Marfan's syndrome, hypertension) can affect aortic elasticity by altering the microstructure and composition of the elastin and collagen fiber networks within the tunica media. Ultrasound tissue characterization techniques can be used to obtain direct measurements of the stiffness coefficients of aorta by measurement of the speed of sound in specific directions. In this study we sought to define the contributions of elastin and collagen to the mechanical properties of aortic media by measuring the magnitude and directional dependence of the speed of sound before and after selective isolation of either the collagen or elastin fiber matrix. Formalin-fixed porcine aortas were sectioned for insonification in the circumferential, longitudinal, or radial direction and examined using high-frequency (50 MHz) ultrasound microscopy. Isolation of the collagen or elastin fiber matrices was accomplished through treatment with NaOH or formic acid, respectively. The results suggest that elastin is the primary contributor to aortic medial stiffness in the unloaded state, and that there is relatively little anisotropy in the speed of sound or stiffness in the aortic wall.

  9. Pentosan polysulfate decreases myocardial expression of the extracellular matrix enzyme ADAMTS4 and improves cardiac function in vivo in rats subjected to pressure overload by aortic banding.

    Directory of Open Access Journals (Sweden)

    Maria Vistnes

    Full Text Available BACKGROUND: We hypothesized that cleavage of the extracellular matrix (ECM proteoglycans versican and aggrecan by ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs proteases, which contributes to stress-induced ECM-reorganization in atherogenesis and osteoarthritis, also play a role in heart failure development. OBJECTIVES: The primary objective was to identify alterations in expression of ADAMTS versicanases and aggrecanases during development of heart failure, while evaluation of the effects of in vivo modulation of relevant changes in ADAMTS activity constituted the secondary objective. METHODS: Myocardial levels of versican, aggrecan, and their ADAMTS cleaving proteases were examined in Wistar rats six weeks after aortic banding (AB, and versican and selected ADAMTS versicanases were further analyzed in neonatal cardiomyocytes (NCM and cardiac fibroblasts (NFB after stimulation by inflammatory mediators. Based on the initial findings, ADAMTS4 was selected the most promising therapeutic target. Thus, rats with AB were treated with pentosan polysulfate (PPS, a polysaccharide with known ADAMTS4-inhibitory properties, and effects on versican fragmentation, left ventricular function and geometry were evaluated. RESULTS: We discovered that myocardial mRNA and protein levels of ADAMTS1 and -4, and mRNA levels of versican, aggrecan, and ADAMTS8 increased after AB, and TNF-α and IL-1β synergistically increased mRNA of versican and ADAMTS4 in NCM and NFB and secretion of ADAMTS4 from NCM. Furthermore, PPS-treatment improved systolic function, demonstrated by an improved fractional shortening (vehicle 48±3% versus PPS 60±1%, p<0.01 after AB. Following PPS-treatment, we observed an ∼80% reduction in myocardial ADAMTS4 mRNA (p = 0.03, and ∼50% reduction in the extracellular amount of the p150 versican fragments (p = 0.05, suggesting reduced versicanase activity. CONCLUSIONS: Our findings suggest that AB induces an

  10. Reoperative transapical transcatheter aortic valve replacement for central aortic regurgitation.

    Science.gov (United States)

    Zhu, Yuanjia; Kapadia, Samir; Krishnaswamy, Amar; Svensson, Lars G; Mick, Stephanie

    2016-09-01

    Paravalvular leak-related aortic regurgitation after transcatheter aortic valve replacement (TAVR) is a common complication and is associated with increased short- and long-term mortality. However, the impact of isolated central aortic regurgitation is unknown. We report a case of transapical (TA) TAVR with postprocedural central aortic regurgitation, who returned after two years with progression of regurgitation. A reoperative valve-in-valve TA-TAVR was performed. PMID:27405799

  11. Aortic regurgitation after transcatheter aortic valve replacement.

    Science.gov (United States)

    Werner, Nikos; Sinning, Jan-Malte

    2014-01-01

    Paravalvular aortic regurgitation (AR) negatively affects prognosis following transcatheter aortic valve replacement (TAVR). As transcatheter heart valves (THV) are anchored using a certain degree of oversizing at the level of the aortic annulus, incomplete stent frame expansion because of heavily annular calcifications, suboptimal placement of the prosthesis, and/or annulus-prosthesis size-mismatch can contribute to paravalvular AR with subsequent increased mortality risk. Echocardiography is essential to differentiate between transvalvular and paravalvular AR and to further elucidate the etiology of AR during the procedure. However, because echocardiographic quantification of AR in TAVR patients remains challenging, especially in the implantation situation, a multimodal approach to the evaluation of AR with use of hemodynamic measurements and imaging modalities is useful to precisely quantify the severity of AR immediately after valve deployment. "Next-generation" THVs are already on the market and first results show that paravalvular AR related to design modifications (eg, paravalvular space-fillers, full repositionability) are rarely seen in these valve types.  PMID:24632758

  12. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... conditions or other significant medical problems, the American College of Cardiology recommends aortic valve replacement for basically ... more likely we see aortic stenosis. Again, patient education is part of the evaluation and management of ...

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... North Carolina. My name is John Streitman and I'm a cardiothoracic surgeon here at the Heart ... the corrective surgery of aortic valve replacement. If I have aortic stenosis, are there any activities that ...

  14. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... of that slide, that demonstrates that patients with New York Heart Association class heart failure 1 and ... right down the aortic valve and that's the new aortic valve that Dr. Streitman's placed. And you ...

  15. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... to help prevent aortic stenosis? There's no prophylactic methods that anybody can take to prevent aortic stenosis ... it will be archived on the ORlive Web site and ORlive.com and, of course, a link ...

  16. Aneurysms: thoracic aortic aneurysms.

    Science.gov (United States)

    Chun, Kevin C; Lee, Eugene S

    2015-04-01

    Thoracic aortic aneurysms (TAAs) have many possible etiologies, including congenital heart defects (eg, bicuspid aortic valves, coarctation of the aorta), inherited connective tissue disorders (eg, Marfan, Ehlers-Danlos, Loeys-Dietz syndromes), and degenerative conditions (eg, medial necrosis, atherosclerosis of the aortic wall). Symptoms of rupture include a severe tearing pain in the chest, back, or neck, sometimes associated with cardiovascular collapse. Before rupture, TAAs may exert pressure on other thoracic structures, leading to a variety of symptoms. However, most TAAs are asymptomatic and are found incidentally during imaging for other conditions. Diagnosis is confirmed with computed tomography scan or echocardiography. Asymptomatic TAAs should be monitored with imaging at specified intervals and patients referred for repair if the TAAs are enlarging rapidly (greater than 0.5 cm in diameter over 6 months for heritable etiologies; greater than 0.5 cm over 1 year for degenerative etiologies) or reach a critical aortic diameter threshold for elective surgery (5.5 cm for TAAs due to degenerative etiologies, 5.0 cm when associated with inherited syndromes). Open surgery is used most often to treat asymptomatic TAAs in the ascending aorta and aortic arch. Asymptomatic TAAs in the descending aorta often are treated medically with aggressive blood pressure control, though recent data suggest that endovascular procedures may result in better long-term survival rates. PMID:25860136

  17. Aortic PWV in Chronic Kidney Disease: A CRIC Ancillary Study

    Science.gov (United States)

    Townsend, Raymond R.; Wimmer, Neil J.; Chirinos, Julio A.; Parsa, Afshin; Weir, Matthew; Perumal, Kalyani; Lash, James P.; Chen, Jing; Steigerwalt, Susan P.; Flack, John; Go, Alan S.; Rafey, Mohammed; Rahman, Mahboob; Sheridan, Angela; Gadegbeku, Crystal A.; Robinson, Nancy A.; Joffe, Marshall

    2009-01-01

    Background Aortic PWV is a measure of arterial stiffness and has proved useful in predicting cardiovascular morbidity and mortality in several populations of patients, including the healthy elderly, hypertensives and those with end stage renal disease receiving hemodialysis. Little data exist characterizing aortic stiffness in patients with chronic kidney disease who are not receiving dialysis, and in particular the effect of reduced kidney function on aortic PWV. Methods We performed measurements of aortic PWV in a cross-sectional cohort of participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased aortic PWV in chronic kidney disease. Results PWV measurements were obtained in 2564 participants. The tertiles of aortic PWV (adjusted for waist circumference) were 10.2 m/sec with an overall mean (± S.D.) value of 9.48 ± 3.03 m/sec [95% CI = 9.35–9.61 m/sec]. Multivariable regression identified significant independent positive associations of age, blood glucose concentrations, race, waist circumference, mean arterial blood pressure, gender, and presence of diabetes with aortic PWV and a significant negative association with the level of kidney function. Conclusions The large size of this unique cohort, and the targeted enrollment of chronic kidney disease participants provides an ideal situation to study the role of reduced kidney function as a determinant of arterial stiffness. Arterial stiffness may be a significant component of the enhanced cardiovascular risk associated with kidney failure. PMID:20019670

  18. Stanford B型主动脉夹层对凝血功能的影响%Influence of type B aortic dissection on coagulation function

    Institute of Scientific and Technical Information of China (English)

    何亮; 郭盛; 杜宇奎

    2011-01-01

    目的 探讨主动脉Stanford B型主动脉夹层患者凝血功能的变化及其临床意义.方法 2002年1月至2011年1月新疆维吾尔自治区人民医院收治stanford B型主动脉夹层99例,选性别与年龄匹配的正常对照组95例,全自动血凝分析仪检测入选人群入院时国际化标准比值(INR)、部分凝血活酶时间(APrr)、纤维蛋白原(FIB)、凝血酶时间(TT)和D-二聚体(DD).结果 夹层组INR、APTY、FIB、DD均高于对照组,TT低于对照组(P均<0.01).主动脉夹层分期内比较,亚急性及慢性期组夹层INR、FIB高于急性期夹层组(P均<0.01),APTr、DD、TT未见明显改变.结论 Stanford B型主动脉夹层表现为凝血与纤溶持续激活,凝血与纤溶间的平衡被破坏而产生高凝状态.%Objective To explore the changes of blood coagulation function and clinical significances in type B Aortic Dissection(AD).Methods 99 patients with type B AD group,95 persons in healthy control group weIe selected respectively(NC).The detection and analysis of international nomtalized ratio(INR),activated partial thromboplastin time(APTT),thrombin time(TT),fibfinogen(Fib)and D dimer(D-D)were conducted.Results INR,APTT,FIB,DD in AD group signifcantly increased compared with NC group,TT decreased respectively(P<0.01).Subacute and chronic AD showed a significant increase in INR and FIB.Corupamd with acute group.P<0.01.Conclusions AD is characterized by activation of both coagulation and fibrinolysis,resulting in an imbalance between coagulation and fibrinolysis that leading to a hypercoagulation state.

  19. Energy’s Shadow Price and Energy Efficiency in China: A Non-Parametric Input Distance Function Analysis

    Directory of Open Access Journals (Sweden)

    Pengfei Sheng

    2015-03-01

    Full Text Available This paper extends prior research on energy inefficiency in China by utilizing a unique shadow price framework allocation in 30 Chinese provinces. We estimate the shadow price for energy input using the framework of production, and use the ratio of the shadow price to the market price to describe energy utilization. Using Chinese provincial-level data from 1998 to 2011, the results of the analysis reveal that shadow prices in China have grown rapidly during the sample period, which signifies that China has improved its performance in energy utilization since 1998. However, there are eighteen provinces whose shadow prices are lower than market prices. This result suggests that energy utilization is at a low level in these provinces and can be improved by a reallocation of inputs.

  20. Inflammatory aortic aneurysms

    DEFF Research Database (Denmark)

    Bitsch, M; Nørgaard, H H; Røder, O;

    1997-01-01

    operated on for abdominal aortic aneurysms without PF in the same period, served as reference group. RESULTS: Preoperative thickness of PF was assessed as > 1 cm in 11 and cm in 10 patients. Ureterolysis was performed in seven patients where the fibrosis caused ureteral obstruction. Postoperative CT...

  1. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... to repair an abdominal aortic aneurysm using a technology called an “endograft,” which is sometimes called the “ ... separate area, and it’s because of this small technology that allows you to do this. Exactly. So ...

  2. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... an abdominal aortic aneurysm. Normally this procedure takes us about 45 minutes to an hour of doctor work time, which is, I think, a fairly quick procedure to replace a major life-threatening problem in the patient’s abdomen. So you can see ...

  3. Aortic Aneurysm Repair

    Medline Plus

    Full Text Available ... the arteries, which is known as atherosclerosis, high blood pressure, smokers, or a family history of abdominal aortic ... imaging. We can integrate ultrasound imaging, the patient’s blood pressure, and so it’s a little bit like being ...

  4. Feasibility of Using Limited-Population-Based Arterial Input Function for Pharmacokinetic Modeling of Osteosarcoma Dynamic Contrast-Enhanced MRI Data

    OpenAIRE

    Wang, YA; Huang, Wei; Panicek, David M.; Schwartz, Lawrence H.; Koutcher, Jason A

    2008-01-01

    For clinical dynamic contrast-enhanced (DCE) MRI studies, it is often not possible to obtain reliable arterial input function (AIF) in each measurement. Thus, it is important to find a representative AIF for pharmacokinetic modeling of DCE-MRI data when individual AIF (Ind-AIF) measurements are not available. A total of 16 patients with osteosarcomas in the lower extremity (knee region) underwent multislice DCE-MRI. Reliable Ind-AIFs were obtained in five patients with a contrast injection ra...

  5. First direct aortic retrievable transcatheter aortic valve implantation in humans.

    Science.gov (United States)

    Chandrasekhar, Jaya; Glover, Chris; Labinaz, Marino; Ruel, Marc

    2014-11-01

    We describe 2 cases in which transcatheter aortic valve implantation was performed with a Portico prosthesis (St Jude Medical, St Paul, MN) through a direct aortic approach. In 1 of the cases, prosthesis retrieval was needed during the procedure and was essential to the successful outcome. This is the first report, to our knowledge, of direct aortic Portico prosthesis implantation, and it highlights the significance of the retrievable nature of this device. PMID:25442452

  6. Imaging analysis of collagen fiber networks in cusps of porcine aortic valves: effect of their local distribution and alignment on valve functionality.

    Science.gov (United States)

    Mega, Mor; Marom, Gil; Halevi, Rotem; Hamdan, Ashraf; Bluestein, Danny; Haj-Ali, Rami

    2016-07-01

    The cusps of native aortic valve (AV) are composed of collagen bundles embedded in soft tissue, creating a heterogenic tissue with asymmetric alignment in each cusp. This study compares native collagen fiber networks (CFNs) with a goal to better understand their influence on stress distribution and valve kinematics. Images of CFNs from five porcine tricuspid AVs are analyzed and fluid-structure interaction models are generated based on them. Although the valves had similar overall kinematics, the CFNs had distinctive influence on local mechanics. The regions with dilute CFN are more prone to damage since they are subjected to higher stress magnitudes. PMID:26406926

  7. Tobacco smoking and aortic aneurysm

    DEFF Research Database (Denmark)

    Sode, Birgitte F; Nordestgaard, Børge G; Grønbæk, Morten;

    2012-01-01

    BACKGROUND: We determined the predictive power of tobacco smoking on aortic aneurysm as opposed to other risk factors in the general population. METHODS: We recorded tobacco smoking and other risk factors at baseline, and assessed hospitalization and death from aortic aneurysm in 15,072 individuals...... General Population Study, respectively. According to the magnitude of the hazard ratios, tobacco consumption was the most important risk factor for hospitalization and death from aortic aneurysm, followed by male sex and hypertension in both cohorts. The population attributable risk of aortic aneurysm...... outcomes due to tobacco consumption was 64% and 47% in the Copenhagen City Heart Study and Copenhagen General Population Study, respectively, and ranked highest among population attributable risks of aortic aneurysm in both cohorts. The absolute 10-year risk for hospitalization or death from aortic...

  8. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A;

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early......: Prostheses with diameter valve size was also smaller in southern compared to northern European patients (21.6 +/- 2.1 mm versus 23.4 +/- 2.2 mm, p

  9. Quadricuspid aortic valve by cardiac magnetic resonance imaging: a case report and review of the literature.

    Science.gov (United States)

    Khan, Shamruz Khan Akerem; Tamin, Syahidah Syed; Araoz, Philip A

    2011-01-01

    Quadricuspid aortic valve (QAV) is a rare congenital cardiac entity. The recognition of QAV has clinical significance as it causes aortic valve dysfunction, commonly aortic regurgitation, and is often associated with other congenital cardiac abnormalities. We showed the important role played by cardiac magnetic resonance imaging in detecting QAV and review the available literature to explain its incidence, diagnosis, classifications, embryology, correlation between morphology of the QAV and its function, associated conditions, and management. PMID:21926862

  10. Infrarenal Aortic Occlusion

    Science.gov (United States)

    Traverso, L. W.; Baker, J. D.; Dainko, E. A.; Machleder, H. I.

    1978-01-01

    Twenty-eight patients with total occlusion of the infrarenal aorta have been seen at the UCLA Hospitals in the past 11 years. Claudication was the presenting complaint in all but one patient, with one-third having ischemic rest pain. The average age of these patients was 54 years, and their histories revealed a surprising absence of myocardial infarction, stroke, or diabetes, although 40% had essential hypertension. Heavy tobacco use, however, was characteristic of the entire group. Arteriography proved valuable in identifying and characterizing the vascular abnormalities, but posed problems in technique and interpretation. Significant distal arterial disease was detected radiographically in only 21% of these patients. Operative correction of the aortic occlusion was performed on 26 patients, 18 by aortic bypass grafts and eight by aorto-iliac endarterectomy, with one early postoperative death. Although the thrombus extended to the renal artery origins in 77% of the cases, a well-designed technical approach did not require renal artery occlusion. Using serial creatinine determinations, one case of renal insufficiency was detected which was associated with prolonged postoperative hypotension. Although the extent of distal disease was more severe in those who underwent bypass, symptoms of claudication returned earlier and were more prominent in the endarterectomy group. This recurrence of systems was not favorably altered by sympathectomy performed concomitantly with the initial procedure. Even though this condition seems to pose difficult technical obstacles and has a poor prognosis, infrarenal aortic occlusion can be successfully treated by aortic bypass, with favorable long-term results, if particular attention is paid to elements of the preoperative evaluation and the intraoperative technical requirements peculiar to this relatively uncommon disease entity. ImagesFig. 1.Fig. 2.Fig. 3. PMID:646479

  11. Micromanaging Abdominal Aortic Aneurysms

    Directory of Open Access Journals (Sweden)

    Lars Maegdefessel

    2013-07-01

    Full Text Available The contribution of abdominal aortic aneurysm (AAA disease to human morbidity and mortality has increased in the aging, industrialized world. In response, extraordinary efforts have been launched to determine the molecular and pathophysiological characteristics of the diseased aorta. This work aims to develop novel diagnostic and therapeutic strategies to limit AAA expansion and, ultimately, rupture. Contributions from multiple research groups have uncovered a complex transcriptional and post-transcriptional regulatory milieu, which is believed to be essential for maintaining aortic vascular homeostasis. Recently, novel small noncoding RNAs, called microRNAs, have been identified as important transcriptional and post-transcriptional inhibitors of gene expression. MicroRNAs are thought to “fine tune” the translational output of their target messenger RNAs (mRNAs by promoting mRNA degradation or inhibiting translation. With the discovery that microRNAs act as powerful regulators in the context of a wide variety of diseases, it is only logical that microRNAs be thoroughly explored as potential therapeutic entities. This current review summarizes interesting findings regarding the intriguing roles and benefits of microRNA expression modulation during AAA initiation and propagation. These studies utilize disease-relevant murine models, as well as human tissue from patients undergoing surgical aortic aneurysm repair. Furthermore, we critically examine future therapeutic strategies with regard to their clinical and translational feasibility.

  12. Modeling the global micrometeor input function in the upper atmosphere observed by high power and large aperture radars

    Science.gov (United States)

    Janches, Diego; Heinselman, Craig J.; Chau, Jorge L.; Chandran, Amal; Woodman, Ronald

    2006-07-01

    We report initial results of an effort to model the diurnal and seasonal variability of the meteor rate detected by high power and large aperture (HPLA) radars. The model uses Monte Carlo simulation techniques and at present assumes that most of the detected particles originate from three radiant distributions with the most dominant concentrated around the Earth's apex. The other two sources are centered 80° in ecliptic longitude to each side of the apex and are commonly known as helion and antihelion. To reproduce the measurements, the apex source flux was set to provide ˜70% of the total number of particles while the other ˜30% is provided by the combined contribution of the two remaining sources. The results of the model are in excellent agreement with observed diurnal curves obtained at different seasons and locations using the 430 MHz Arecibo radar in Puerto Rico, the 50 MHz Jicamarca radar in Perú, and the 1.29 GHz Sondrestrom radar in Greenland. To obtain agreement with the observed diurnal and seasonal variability of the meteor rate, an empirical atmospheric filtering effect was introduced in the simulation which prevents meteors with low-elevation radiants (≤20°) from being detected by the radars at mesospheric altitudes. The filtering effect is probably produced by a combination of factors related to the interaction of the meteor with the air molecules such as electron production and/or the ablation at higher altitudes. On the basis of these results we calculate the micrometeor global, diurnal, and seasonal input in the upper atmosphere.

  13. Image-derived and arterial blood sampled input functions for quantitative PET imaging of the angiotensin II subtype 1 receptor in the kidney

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Tao; Tsui, Benjamin M. W.; Li, Xin; Vranesic, Melin; Lodge, Martin A.; Gulaldi, Nedim C. M.; Szabo, Zsolt, E-mail: zszabo@jhmi.edu [Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins School of Medicine, Baltimore, Maryland 21287 (United States)

    2015-11-15

    Purpose: The radioligand {sup 11}C-KR31173 has been introduced for positron emission tomography (PET) imaging of the angiotensin II subtype 1 receptor in the kidney in vivo. To study the biokinetics of {sup 11}C-KR31173 with a compartmental model, the input function is needed. Collection and analysis of arterial blood samples are the established approach to obtain the input function but they are not feasible in patients with renal diseases. The goal of this study was to develop a quantitative technique that can provide an accurate image-derived input function (ID-IF) to replace the conventional invasive arterial sampling and test the method in pigs with the goal of translation into human studies. Methods: The experimental animals were injected with [{sup 11}C]KR31173 and scanned up to 90 min with dynamic PET. Arterial blood samples were collected for the artery derived input function (AD-IF) and used as a gold standard for ID-IF. Before PET, magnetic resonance angiography of the kidneys was obtained to provide the anatomical information required for derivation of the recovery coefficients in the abdominal aorta, a requirement for partial volume correction of the ID-IF. Different image reconstruction methods, filtered back projection (FBP) and ordered subset expectation maximization (OS-EM), were investigated for the best trade-off between bias and variance of the ID-IF. The effects of kidney uptakes on the quantitative accuracy of ID-IF were also studied. Biological variables such as red blood cell binding and radioligand metabolism were also taken into consideration. A single blood sample was used for calibration in the later phase of the input function. Results: In the first 2 min after injection, the OS-EM based ID-IF was found to be biased, and the bias was found to be induced by the kidney uptake. No such bias was found with the FBP based image reconstruction method. However, the OS-EM based image reconstruction was found to reduce variance in the subsequent

  14. Systems and methods for reconfiguring input devices

    Science.gov (United States)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  15. Assessment of the influence of the compliant aortic root on aortic valve mechanics by means of a geometrical model.

    Science.gov (United States)

    Redaelli, A; Di Martino, E; Gamba, A; Procopio, A M; Fumero, R

    1997-12-01

    In recent years several researchers have suggested that the changes in the geometry and angular dimensions of the aortic root which occur during the cardiac cycle are functional to the optimisation of aortic valve function, both in terms of diminishing leaflet stresses and of fluid-dynamic behaviour. The paper presents an analytical parametric model of the aortic valve which includes the aortic root movement. The indexes used to evaluate the valve behaviour are the circumferential membrane stress and the stress at the free edge of the leaflet, the index of bending strain, the bending of the leaflet at the line attachment in the radial and circumferential directions and the shape of the conduit formed by the leaflets during systole. In order to evaluate the role of geometric changes in valve performance, two control cases were considered, with different reference geometric configuration, where the movement of the aortic root was ignored. The results obtained appear consistent with physiological data, especially with regard to the late diastolic phase and the early ejection phase, and put in evidence the role of the aortic root movement in the improvement of valve behaviour. PMID:9450254

  16. The multiple-function multi-input/multi-output digital controller system for the AFW wind-tunnel model

    Science.gov (United States)

    Hoadley, Sherwood T.; Mcgraw, Sandra M.

    1992-01-01

    A real time multiple-function digital controller system was developed for the Active Flexible Wing (AFW) Program. The digital controller system (DCS) allowed simultaneous execution of two control laws: flutter suppression and either roll trim or a rolling maneuver load control. The DCS operated within, but independently of, a slower host operating system environment, at regulated speeds up to 200 Hz. It also coordinated the acquisition, storage, and transfer of data for near real time controller performance evaluation and both open- and closed-loop plant estimation. It synchronized the operation of four different processing units, allowing flexibility in the number, form, functionality, and order of control laws, and variability in the selection of the sensors and actuators employed. Most importantly, the DCS allowed for the successful demonstration of active flutter suppression to conditions approximately 26 percent (in dynamic pressure) above the open-loop boundary in cases when the model was fixed in roll and up to 23 percent when it was free to roll. Aggressive roll maneuvers with load control were achieved above the flutter boundary. The purpose here is to present the development, validation, and wind tunnel testing of this multiple-function digital controller system.

  17. Cerebral blood flow with [15O]water PET studies using an image-derived input function and MR-defined carotid centerlines

    Science.gov (United States)

    Fung, Edward K.; Carson, Richard E.

    2013-03-01

    Full quantitative analysis of brain PET data requires knowledge of the arterial input function into the brain. Such data are normally acquired by arterial sampling with corrections for delay and dispersion to account for the distant sampling site. Several attempts have been made to extract an image-derived input function (IDIF) directly from the internal carotid arteries that supply the brain and are often visible in brain PET images. We have devised a method of delineating the internal carotids in co-registered magnetic resonance (MR) images using the level-set method and applying the segmentations to PET images using a novel centerline approach. Centerlines of the segmented carotids were modeled as cubic splines and re-registered in PET images summed over the early portion of the scan. Using information from the anatomical center of the vessel should minimize partial volume and spillover effects. Centerline time-activity curves were taken as the mean of the values for points along the centerline interpolated from neighboring voxels. A scale factor correction was derived from calculation of cerebral blood flow (CBF) using gold standard arterial blood measurements. We have applied the method to human subject data from multiple injections of [15O]water on the HRRT. The method was assessed by calculating the area under the curve (AUC) of the IDIF and the CBF, and comparing these to values computed using the gold standard arterial input curve. The average ratio of IDIF to arterial AUC (apparent recovery coefficient: aRC) across 9 subjects with multiple (n = 69) injections was 0.49 ± 0.09 at 0-30 s post tracer arrival, 0.45 ± 0.09 at 30-60 s, and 0.46 ± 0.09 at 60-90 s. Gray and white matter CBF values were 61.4 ± 11.0 and 15.6 ± 3.0 mL/min/100 g tissue using sampled blood data. Using IDIF centerlines scaled by the average aRC over each subjects’ injections, gray and white matter CBF values were 61.3 ± 13.5 and 15.5 ± 3.4 mL/min/100 g tissue. Using global

  18. Balloon aortic valvuloplasty as a bridge to aortic valve surgery for severe aortic stenosis.

    Science.gov (United States)

    Nwaejike, Nnamdi; Mills, Keith; Stables, Rod; Field, Mark

    2015-03-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, in patients with severe aortic stenosis, can balloon valvuloplasty be used as a bridge to aortic valve replacement? Altogether 463 papers were found using the reported search, of which 11 papers represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that balloon aortic valvuloplasty is recommended as a bridge to aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI) in patients with severe symptomatic aortic stenosis. Institutional practices, local and logistic factors can affect patient selection and management approaches to severe aortic stenosis, but having the facility to offer balloon aortic valvuloplasty (especially in the TAVI era) provides another management option for patients who would otherwise have been considered unacceptably high risk for aortic valve surgery. The increased incidence of balloon aortic valvuloplasty mirrors the increase in the use of TAVI with a sharp increase in activity from 2006. Success rates for bridging from balloon aortic valvuloplasty to definite surgical intervention are in the range 26.3-74%, with AVR or TAVI occurring within 8 weeks to 7 months. Complications from balloon aortic valvuloplasty such as aortic regurgitation (AR) can be managed successfully. Up to 40% of patients selected by balloon aortic valvuloplasty to have TAVI or AVR do not have these procedures within 2 years. While most of these patients are excluded for objective clinical reasons such as terminal disease/malignancy or other persistent contraindication, some patients refuse definitive treatment and others die while on the waiting list. Outcomes in patients bridged to AVR/TAVI are better than in patients treated with balloon aortic valvuloplasty

  19. Linear functional observers with guaranteed ɛ-convergence for discrete time-delay systems with input/output disturbances

    Science.gov (United States)

    Nguyen, M. C.; Trinh, H.; Nam, P. T.

    2016-10-01

    The problem of designing linear functional observers for discrete time-delay systems with unknown-but-bounded disturbances in both the plant and the output is considered for the first time in this paper. A novel approach to design a minimum-order observer is proposed to guarantee that the observer error is ε-convergent, which means that the estimate converges robustly within an ε-bound of the true state. Conditions for the existence of this observer are first derived. Then, by utilising an extended Lyapunov-Krasovskii functional and the free-weighting matrix technique, a sufficient condition for ε-convergence of the observer error system is given. This condition is presented in terms of linear matrix inequalities with two parameters needed to be tuned, so that it can be efficiently solved by incorporating a two-dimensional search method into convex optimisation algorithms to obtain the smallest possible value for ε. Three numerical examples, including the well-known single-link flexible joint robotic system, are given to illustrate the feasibility and effectiveness of our results.

  20. ED 02-3 CLINICAL IMPLICATIONS OF CENTRAL HEMODYNAMICS ON AORTIC AND END-ORGAN DISEASES.

    Science.gov (United States)

    Hashimoto, Junichiro

    2016-09-01

    The central aorta constitutes the main trunk of the systemic arterial tree. It dilates passively with cardiac ejection during systole and then constricts with its recoil function during diastole, thereby regulating blood pressure and blood flow. The central pulsatile hemodynamics affects local hemodynamics within as well as downstream of the aorta (e.g., end organs).The aorta progressively stiffens and dilates with advancing age, and such age-dependent change is accelerated by hypertension. According to the law of Laplace, wall stress depends on the diameter and pressure of the blood vessel. This has been confirmed by substantial studies which have associated baseline aortic diameter with subsequent development of aortic dissection and progressive dilatation of aortic lumen. This law can also imply potential importance of local pressure within the aorta (i.e., the central pressure) in predicting the development and progression of aortic aneurysms.Several previous studies have shown that hypertension (together with age and obesity) is related to dilatation of the proximal ascending aorta (rather than of the aortic root). In addition, aortic blood flow abnormality may also be importantly related to aortic dilatation because of strong positive association between the diastole flow reversal and lumen diameter in the proximal thoracic aorta. As for the abdominal (infrarenal) aorta, aneurysmal development and progression have been attributed to aortic segmental stiffening (of the bifurcational versus infrarenal segment) and aortic pressure elevation, respectively.Central pulsatile pressure not only represents aortic wall stress but also determines cardiac afterload and microvascular wall stress in the brain and kidney. Central pulsatile flow (in both directions) could also affect the flow distribution into the upper and lower parts of the body and control end-organ function. Aortic structural change (including segmental stiffening and aneurysmal formation) causes central

  1. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy...... operations were completed as mini-sternotomies, 4 died later of noncardiac causes. The aortic cross-clamp and perfusion times were significantly different across all groups (P valve replacement...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  2. A computerized system for video analysis of the aortic valve.

    Science.gov (United States)

    Vesely, I; Menkis, A; Campbell, G

    1990-10-01

    A novel technique was developed to study the dynamic behavior of the porcine aortic valve in an isolated heart preparation. Under the control of a personal computer, a video frame grabber board continuously acquired and digitized images of the aortic valve, and an analog-to-digital (A/D) converter read four channels of physiological data (flow rate, aortic and ventricular pressure, and aortic root diameter). The valve was illuminated with a strobe light synchronized to fire at the field acquisition rate of the CCD video camera. Using the overlay bits in the video board, the measured parameters were super-imposed over the live video as graphical tracing, and the resultant composite images were recorded on-line to video tape. The overlaying of the valve images with the graphical tracings of acquired data enabled the data tracings to be precisely synchronized with the video images of the aortic valve. This technique enabled us to observe the relationship between aortic root expansion and valve function.

  3. 基于多输入特征寄存器的哈希方法%GAO Shujing Hash function based on multiple input signature analysis registers

    Institute of Scientific and Technical Information of China (English)

    高树静

    2013-01-01

    无源器件的能量和计算资源有限。针对这种器件的安全认证需求,提出了一种新的哈希方法M-hash。该方法基于低复杂性的并行输入LFSR,即多输入特征分析寄存器(MISR),采用并行压缩方法,具有硬件复杂性低、速度快等特点。理论分析和具体硬件实现表明,M-hash在硬件复杂性、压缩速度和安全性等方面均优于另外一种基于LFSR的Toeplitz哈希方法。%Passive devices have limit power and computing resource. Aiming at the security authentication of this kind of devices, a new hash function-M-hash is proposed. Based on low hardware complexity parallel input Linear Feedback Shift Register(LFSR), Multiple Input Signature Register(MISR), the M-hash takes parallel compaction method and with property of low hardware complexity and high speed. Theory analysis and hardware implementation show that M-hash is better than Toeplitz hash functions that are also based on LFSR in aspects of hardware complexity, compaction speed and security.

  4. Examination and clinical significance of coagulation function of patients with Type B Aortic Dissection%Stanford B型主动脉夹层动脉瘤患者凝血功能检测的意义

    Institute of Scientific and Technical Information of China (English)

    庞秀慧

    2011-01-01

    目的 探讨主动脉Stanford B型主动脉夹层动脉瘤(AD)患者凝血功能的变化及其临床意义.方法 2002-01-2011-01新疆维吾尔自治区人民医院收治Stanford B型主动脉夹层99例,选性别与年龄匹配的正常对照组95例,全自动血凝分析仪检测国际化标准比值(INR)、部分凝血活酶时间(APTT)、纤维蛋白原(FIB)和凝血酶时间(TT)、D-二聚体(DD).结果 AD组INR、APTT、FIB、DD均高于NC组,TT低于NC组,P<0.01.主动脉夹层分期内比较,亚急性及慢性组夹层INR、FIB高于急性期夹层组,APTT、DD、TT未见明显改变.结论 AD表现为凝血与纤溶持续激活,由于凝血与纤溶间的平衡破坏而产生高凝状态.%To explore the changes of blood coagulation function and clinical significances in type B aortic dissection( AD). Methods 99 patients with type B aortic dissection group,95 persons in healthy control group were selected respectively(NC) and the detection and analysis of international normalized ratio (INR), activated partial thromboplastin time(APTT),thrombin time(TT), fibrinogen(Fib) and D-dimer(D-D) were conducted. Results INR, APTT,FIB,DD in AD group significiantly increased compared with NC group,TT decreased respectively (P< 0. 01).Subact and chronic aortic dissection showed a significant increase in INR, Fib, compared with acute group. Conclusion AD is characterized by activation of both coagulation and fibrinolysis, resulting in an imbalance between coagulation and fibrinolysis leading to a hypercoagulation state.

  5. Valve-sparing aortic root replacement and aortic valve repair in a patient with acromegaly and aortic root dilatation

    Directory of Open Access Journals (Sweden)

    Karel Van Praet

    2015-07-01

    Full Text Available Aortic regurgitation and dilatation of the aortic root and ascending aorta are severe complications of acromegaly. The current trend for management of an aortic root aneurysm is valve-sparing root replacement as well as restoring the diameter of the aortic sinotubular junction (STJ and annulus. Our case report supports the recommendation that in patients with acromegaly, severe aortic root involvement may indicate the need for surgery.

  6. Abdominal aortic aneurysm surgery

    DEFF Research Database (Denmark)

    Gefke, K; Schroeder, T V; Thisted, B;

    1994-01-01

    The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553......, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems....

  7. Unoperated aortic aneurysm

    DEFF Research Database (Denmark)

    Perko, M J; Nørgaard, M; Herzog, T M;

    1995-01-01

    . No significant differences in survival for patients with dissecting and nondissecting AA were detected. In all, 132 patients (78%) died and 78 (59%) of them died of rupture. Mean time to rupture was 1,300 +/- 8 days. Cumulative 5-year hazard of rupture for the dissecting AA was twice that of the nondissecting (p......From 1984 to 1993, 1,053 patients were admitted with aortic aneurysm (AA) and 170 (15%) were not operated on. The most frequent reason for nonoperative management was presumed technical inoperability. Survivals for patients with thoracic, thoracoabdominal, and abdominal AA were comparable...

  8. Structure and function of natural sulphide-oxidizing microbial mats under dynamic input of light and chemical energy.

    Science.gov (United States)

    Klatt, Judith M; Meyer, Steffi; Häusler, Stefan; Macalady, Jennifer L; de Beer, Dirk; Polerecky, Lubos

    2016-04-01

    We studied the interaction between phototrophic and chemolithoautotrophic sulphide-oxidizing microorganisms in natural microbial mats forming in sulphidic streams. The structure of these mats varied between two end-members: one characterized by a layer dominated by large sulphur-oxidizing bacteria (SOB; mostly Beggiatoa-like) on top of a cyanobacterial layer (B/C mats) and the other with an inverted structure (C/B mats). C/B mats formed where the availability of oxygen from the water column was limited (45 μM) and continuously present. Here SOB were independent of the photosynthetic activity of cyanobacteria and outcompeted the cyanobacteria in the uppermost layer of the mat where energy sources for both functional groups were concentrated. Outcompetition of photosynthetic microbes in the presence of light was facilitated by the decoupling of aerobic chemolithotrophy and oxygenic phototrophy. Remarkably, the B/C mats conserved much less energy than the C/B mats, although similar amounts of light and chemical energy were available. Thus ecosystems do not necessarily develop towards optimal energy usage. Our data suggest that, when two independent sources of energy are available, the structure and activity of microbial communities is primarily determined by the continuous rather than the intermittent energy source, even if the time-integrated energy flux of the intermittent energy source is greater. PMID:26405833

  9. Centrifugal pump support for distal aortic perfusion during repair of traumatic thoracic aortic injury.

    Science.gov (United States)

    Walls, Joseph T; Curtis, Jack J; McKenney-Knox, Charlotte A; Schmaltz, Richard A

    2002-11-01

    Paraplegia from ischemic injury of the spinal cord and renal failure from inadequate perfusion of the kidneys may occur from aortic cross-clamping during repair of traumatic thoracic aortic injuries. After Institutional Review Board approval, we retrospectively reviewed the charts of 26 patients surgically treated for traumatic transection of the descending thoracic aorta during a 14 year period (1987-2001), using centrifugal pump (Sarns) support for distal aortic perfusion. The study group comprised 19 males and 7 females, whose ages ranged from 15 to 69 years. For all but 1 patient, who fell from a flagpole, the injuries were incurred in motor vehicle accidents. Aortic cross-clamp time lasted between 5 to 78 min (median = 40 min). Mean arterial pressure ranged from 50 to 80 mm Hg (median = 70 mm Hg). All patients survived operation without developing paraplegia or renal failure. Distal centrifugal pump perfusion during repair of traumatic injury of the descending thoracic aorta is a valuable adjunct during surgical treatment and aids in preservation of spinal cord and renal function.

  10. Aortic Valve Replacement for Infective Endocarditis in a Renal Transplant Recipient

    OpenAIRE

    Masmoudi Sayda; Frikha Imed; Trigui Walid; Karoui Abdelhamid; Daoud Moncef; Sahnoun Youssef

    2000-01-01

    Renal transplant recipients are more prone to developing infections. We report a 37-year old renal transplant recipient who developed infective endocarditis of the aortic valve, heart failure and renal allograft dysfunction. He underwent aortic valve replacement which was followed by improvement in cardiac as well as allograft function.

  11. Aortic Valve Replacement for Infective Endocarditis in a Renal Transplant Recipient

    Directory of Open Access Journals (Sweden)

    Masmoudi Sayda

    2000-01-01

    Full Text Available Renal transplant recipients are more prone to developing infections. We report a 37-year old renal transplant recipient who developed infective endocarditis of the aortic valve, heart failure and renal allograft dysfunction. He underwent aortic valve replacement which was followed by improvement in cardiac as well as allograft function.

  12. Abdominal aortic grafting for spontaneous infrarenal abdominal aortic dissection.

    Science.gov (United States)

    Iwasaki, Hiroto; Shibuya, Takashi; Shintani, Takashi; Uenaka, Hisazumi; Suehiro, Shigefumi; Satoh, Hisashi

    2010-02-01

    This case report concerns a 62-year-old woman with spontaneous infrarenal abdominal aortic dissection, which developed into claudication and rest pain in the lower extremity. Multi-row detector computed tomography showed the entry site of the abdominal aortic dissection at the second lumbar artery, while the reentry site was found intraoperatively at the median sacral artery, indicating that the false lumen had progressed and compressed the true lumen. A direct approach involving grafting appears to be an effective procedure for resolving mesenteric and lower extremity hypoperfusion due to aortic dissection with a dilated false channel, even during the acute period. PMID:19879731

  13. Reinforced aortic root reconstruction for acute type A aortic dissection involving the aortic root

    Directory of Open Access Journals (Sweden)

    Han Qing-qi

    2013-06-01

    Full Text Available OBJECTIVE: There are debates regarding the optimal approach for AAAD involving the aortic root. We described a modified reinforced aortic root reconstruction approach for treating AAAD involving the aortic root. METHODS: A total of 161 patients with AAAD involving the aortic root were treated by our modified reinforced aortic root reconstruction approach from January 1998 to December 2008. Key features of our modified approach were placement of an autologous pericardial patch in the false lumen, lining of the sinotubular junction lumen with a polyester vascular ring, and wrapping of the vessel with Teflon strips. Outcome measures included post-operative mortality, survival, complications, and level of aortic regurgitation. RESULTS: A total of 161 patients were included in the study (mean age: 43.3 1 15.5 years. The mean duration of follow-up was 5.1 1 2.96 years (2-12 years. A total of 10 (6.2% and 11 (6.8% patients died during hospitalization and during follow-up, respectively. Thirty-one (19.3% patients experienced postoperative complications. The 1-, 3-, 5-, and 10-year survival rates were 99.3%, 98%, 93.8%, and 75.5%, respectively. There were no instances of recurrent aortic dissection, aortic aneurysm, or pseudoaneurysm during the entire study period. The severity of aortic regurgitation dramatically decreased immediately after surgery (from 28.6% to 0% grade 3-4 and thereafter slightly increased (from 0% to 7.2% at 5 years and 9.1% at 10 years. CONCLUSION: This modified reinforced aortic root reconstruction was feasible, safe and durable/effective, as indicated by its low mortality, low postoperative complications and high survival rate.

  14. A semi-empirical model of the contribution from sporadic meteoroid sources on the meteor input function in the MLT observed at Arecibo

    Science.gov (United States)

    Fentzke, Jonathan T.; Janches, Diego

    2008-03-01

    In this paper, we present a modeling and observational study of the micrometeor input function with a focus on understanding how each of the extraterrestrial sporadic meteoroid sources contributes to the observed meteoric flux in the Mesosphere and Lower Thermosphere (MLT) atmospheric region. For this purpose, we expand the model presented by Janches et al. (2006) using a Monte Carlo technique and incorporating: 1) a widely accepted global mass flux, which is divided into different proportions among the known sporadic meteoroid sources as the initial input above Earth's atmosphere; 2) contemporary knowledge on the source's velocity and radiant distributions; and 3) the full integration of the canonical meteor equations that describe the meteoroid entry and ablation physics. In addition, we constrain the initial input through a comparison of our modeled results with meteor observations obtained with the 430 MHz High Power and Large Aperture (HPLA) Arecibo radar in Puerto Rico that covers all seasons. The predicted meteor rates and velocity distributions are in excellent agreement with the observed ones without the need for any additional normalization factor. Our results indicate that although the Earth's Apex centered radiant source, which is characterized by high geocentric speeds (˜55 km/s), appears to be ˜33% of the meteoroids in the Solar System at 1 AU, it accounts for ˜60% of the meteors observed by the Arecibo HPLA radar in the atmosphere. The remaining 40% of observed meteors originate mostly from the Helion and Anti-Helion sources, with a very small, but constant during the day, contribution of the South and North Toroidal sources. These results also suggest that particles smaller than ˜10-3μg with slow velocities (<30 km/s) will not significantly ablate and never become observable meteors. The motivation of this effort is to construct a new and more precise MIF model needed for the subsequent modeling of the atmospheric phenomena related to the

  15. Chaos and asymptotical stability in discrete-time recurrent neural networks with generalized input-output function

    Institute of Scientific and Technical Information of China (English)

    WANG; Jinliang

    2001-01-01

    Surveys, 1993, 7: 305.[16]Shephand, N., Statistical aspects of ARCH and stochastic volatility, in Time Series Models in Econometrics, Finance and Other Fields (eds. Cox, D. R., Hinkley, D. V., Barndorff-Nielsen, O. E.), London: Chapman & Hall, 1996, 1.[17]Pantula, S. G., Estimation of autoregressive models with ARCH errors, Sankhya, Ser. B, 1988, 50: 119.[18]Campbell, J. Y., Lo, A. W., Mackinlay, A. C., The Econometrics of Financial Markets, Princeton: Princeton University Press, 1997, 488.[19]Fan, J., Gijbels, I., Local Polynomial Modeling and Its Applications, London: Chapman & Hall, 1996.[20]Lu, Z. D., A note on geometric ergodicity of autoregressive conditional heteroscedasticity (ARCH) model, Statistics and Probability Letters, 1996, 30: 305.[21]Robinson, P. M., Nonparametric estimators for time series, Journal of Time Series Analysis, 1983, 4: 185.[22]Stone, C. J., Optimal rates of convergence for nonparametric estimators, Annals of Statistics, 1980, 8: 1348.[23]Stone, C. J., Optimal global rates of convergence for nonparametric kernel regression, Annals of Statistics, 1982, 10: 1040.[24]Truong, Y. M., Stone, C. J., Nonparametric function estimation involving time series, Annals of Statistics, 1992, 20: 77.[25]Masry, E., Multivariate polynomial regression for time series; uniform strong consistency and rates, Journal of Time Series Analysis, 1996, 17: 571.[26]Ruppert, D., Wand, M. P., Multivariate locally weighted least squares regression, Annals of Statistics, 1994, 22: 1346.[27]Bollerslev, T., Generalized autoregressive conditional heteroscedasticity, Journal of Econometrics, 1986, 31: 307.[28]Engle, R. F., Granger, C. W. J., Co-integration and error-correction: representation, estimation and testing, Econometrica, 1987, 55: 251.

  16. Enhancing 4D PC-MRI in an aortic phantom considering numerical simulations

    Science.gov (United States)

    Kratzke, Jonas; Schoch, Nicolai; Weis, Christian; Müller-Eschner, Matthias; Speidel, Stefanie; Farag, Mina; Beller, Carsten J.; Heuveline, Vincent

    2015-03-01

    To date, cardiovascular surgery enables the treatment of a wide range of aortic pathologies. One of the current challenges in this field is given by the detection of high-risk patients for adverse aortic events, who should be treated electively. Reliable diagnostic parameters, which indicate the urge of treatment, have to be determined. Functional imaging by means of 4D phase contrast-magnetic resonance imaging (PC-MRI) enables the time-resolved measurement of blood flow velocity in 3D. Applied to aortic phantoms, three dimensional blood flow properties and their relation to adverse dynamics can be investigated in vitro. Emerging "in silico" methods of numerical simulation can supplement these measurements in computing additional information on crucial parameters. We propose a framework that complements 4D PC-MRI imaging by means of numerical simulation based on the Finite Element Method (FEM). The framework is developed on the basis of a prototypic aortic phantom and validated by 4D PC-MRI measurements of the phantom. Based on physical principles of biomechanics, the derived simulation depicts aortic blood flow properties and characteristics. The framework might help identifying factors that induce aortic pathologies such as aortic dilatation or aortic dissection. Alarming thresholds of parameters such as wall shear stress distribution can be evaluated. The combined techniques of 4D PC-MRI and numerical simulation can be used as complementary tools for risk-stratification of aortic pathology.

  17. Dopamine modulation of GABAergic function enables network stability and input selectivity for sustaining working memory in a computational model of the prefrontal cortex.

    Science.gov (United States)

    Lew, Sergio E; Tseng, Kuei Y

    2014-12-01

    Dopamine modulation of GABAergic transmission in the prefrontal cortex (PFC) is thought to be critical for sustaining cognitive processes such as working memory and decision-making. Here, we developed a neurocomputational model of the PFC that includes physiological features of the facilitatory action of dopamine on fast-spiking interneurons to assess how a GABAergic dysregulation impacts on the prefrontal network stability and working memory. We found that a particular non-linear relationship between dopamine transmission and GABA function is required to enable input selectivity in the PFC for the formation and retention of working memory. Either degradation of the dopamine signal or the GABAergic function is sufficient to elicit hyperexcitability in pyramidal neurons and working memory impairments. The simulations also revealed an inverted U-shape relationship between working memory and dopamine, a function that is maintained even at high levels of GABA degradation. In fact, the working memory deficits resulting from reduced GABAergic transmission can be rescued by increasing dopamine tone and vice versa. We also examined the role of this dopamine-GABA interaction for the termination of working memory and found that the extent of GABAergic excitation needed to reset the PFC network begins to occur when the activity of fast-spiking interneurons surpasses 40 Hz. Together, these results indicate that the capability of the PFC to sustain working memory and network stability depends on a robust interplay of compensatory mechanisms between dopamine tone and the activity of local GABAergic interneurons. PMID:24975022

  18. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... see we've used the cautery to achieve access to the sternum. On the left hand side ... wound, which allows us to get more ready access to the aorta and the aortic valve. The ...

  19. Transcatheter Aortic Heart Valve Thrombosis

    DEFF Research Database (Denmark)

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;

    2016-01-01

    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  20. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... No medications as such have been proven to slow that disease path life. Again, it's a progressive ... no medical therapy that has been proven to slow or reverse the process of aortic stenosis. Clearly, ...

  1. [ENDOVASCULAR ABDOMINAL AORTIC ANEURISM REPAIR].

    Science.gov (United States)

    Maĭstrenko, D N; Generalov, M I; Tarazov, P G; Zherebtsov, F K; Osovskikh, V V; Ivanov, A S; Oleshchuk, A N; Granov, D A

    2015-01-01

    The authors analyzed the single-center experience of treatment of 72 patients with abdominal aortic aneurisms and severe accompanied pathology. The aneurisms were repaired by stent-grafts. All the patients had abdominal aortic aneurisms with the diameters from 41 to 84 mm against the background of severe somatic pathology. It was a contraindication to planned open surgery. An installation of stent-graft was successful in all 72 follow-ups. It wasn't necessary to use a conversion to open surgery. The follow-up period consisted of 44,6?2,1 months. Control ultrasound and computer tomography studies hadn't revealed an increase of aneurism sack sizes or "eakages". A reduction of abdominal aortic aneurism sizes was noted in 37 patients on 4-5% during first year after operation. The stent-graft implantation extends the possibilities of abdominal aortic aneurism treatment for patients from a high surgical risk group. PMID:26234059

  2. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... to minimize their symptoms, but that doesn't impact the course of the disease itself. When I' ... more likely we see aortic stenosis. Again, patient education is part of the evaluation and management of ...

  3. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... for patients who would not tolerate well a traditional open operation or a less invasive operation, as ... physical reserve. So Barbara Bush recently had a traditional aortic valve replacement surgery. What makes a patient ...

  4. Adult thoracic and abdominal aortic

    Directory of Open Access Journals (Sweden)

    Randa O. Kaddah

    2016-06-01

    Conclusion: Aortic COA could be found in any segment of the aorta. Proper identification of the anatomical details and pressure gradient studies are important factors affecting the plan of management.

  5. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... symptoms and ultimately surgery may be in the future. The symptoms seen primarily with aortic stenosis at ... echocardiography is? Echocardiography is the use of ultrasound technology. Ultrasound technology is a form of the same ...

  6. CONGENITAL QUADRICUSPID AORTIC-VALVE

    NARCIS (Netherlands)

    BROUWER, MHJ; DEGRAAF, JJ; EBELS, T

    1993-01-01

    Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

  7. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... somebody for this operation. Again, there's no medical therapy that has been proven to slow or reverse ... to their physician. This may lead to earlier treatment and better outcomes as well. Aortic stenosis, as ...

  8. Automatic input rectification

    OpenAIRE

    Long, Fan; Ganesh, Vijay; Carbin, Michael James; Sidiroglou, Stelios; Rinard, Martin

    2012-01-01

    We present a novel technique, automatic input rectification, and a prototype implementation, SOAP. SOAP learns a set of constraints characterizing typical inputs that an application is highly likely to process correctly. When given an atypical input that does not satisfy these constraints, SOAP automatically rectifies the input (i.e., changes the input so that it satisfies the learned constraints). The goal is to automatically convert potentially dangerous inputs into typical inputs that the ...

  9. Intra-aortic balloon pump use does not affect the renal function in patients undergoing off pump coronary artery bypass surgery

    Directory of Open Access Journals (Sweden)

    Muniraju Geetha

    2011-01-01

    Full Text Available Renal dysfunction is known to occur during cardiac surgery. A few factors such as perioperative hypotension, use of potential nephrotoxic therapeutic agents, radio opaque contrast media in the recent past, intra-aortic balloon pump (IABP and cardiopulmonary bypass have been blamed as the contributing factors to the causation of postoperative renal dysfunction in cardiac surgical patients. At times, in patients with renal failure and low cardiac output status, one may face the dilemma if the use of IABP is safe. We undertook this prospective observational study to determine the degree of possible renal injury when IABP is used by measuring serial values of serum creatinine and Cystatin C. Elective patients scheduled for off-pump coronary artery bypass surgery requiring preoperative use of IABP were included in this study. Cystatin C and serum creatinine levels were checked at fixed intervals after institution of IABP. Twenty-two patients were eligible for enrolment to the study. There was no significant change in the values of serum creatinine; from the basal value of 1.10 ± 0.233 to 0.98 ± 0.363 mg /dL (P value >0.05. Cystatin C levels significantly decreased from the basal level of 0.98 ± 0.29 to 0.89 ± 0.23 (P value <0.05. Contrary to the belief, Cystatin C, the early indicator of renal dysfunction decreases suggesting absence of renal injury after the use of IABP. Absence of elevation of cystatin C levels in our study suggests the lack of potential of the IABP to cause renal dysfunction in patients who received elective IABP therapy preoperatively.

  10. Immersed boundary-finite element model of fluid-structure interaction in the aortic root

    Science.gov (United States)

    Flamini, Vittoria; DeAnda, Abe; Griffith, Boyce E.

    2016-04-01

    It has long been recognized that aortic root elasticity helps to ensure efficient aortic valve closure, but our understanding of the functional importance of the elasticity and geometry of the aortic root continues to evolve as increasingly detailed in vivo imaging data become available. Herein, we describe a fluid-structure interaction model of the aortic root, including the aortic valve leaflets, the sinuses of Valsalva, the aortic annulus, and the sinotubular junction, that employs a version of Peskin's immersed boundary (IB) method with a finite element description of the structural elasticity. As in earlier work, we use a fiber-based model of the valve leaflets, but this study extends earlier IB models of the aortic root by employing an incompressible hyperelastic model of the mechanics of the sinuses and ascending aorta using a constitutive law fit to experimental data from human aortic root tissue. In vivo pressure loading is accounted for by a backward displacement method that determines the unloaded configuration of the root model. Our model yields realistic cardiac output at physiological pressures, with low transvalvular pressure differences during forward flow, minimal regurgitation during valve closure, and realistic pressure loads when the valve is closed during diastole. Further, results from high-resolution computations indicate that although the detailed leaflet and root kinematics show some grid sensitivity, our IB model of the aortic root nonetheless produces essentially grid-converged flow rates and pressures at practical grid spacings for the high Reynolds number flows of the aortic root. These results thereby clarify minimum grid resolutions required by such models when used as stand-alone models of the aortic valve as well as when used to provide models of the outflow valves in models of left-ventricular fluid dynamics.

  11. Novel pharmacological strategies to prevent aortic complications in Marfan syndrome

    Institute of Scientific and Technical Information of China (English)

    Peter Matt; Friedrich Eckstein

    2011-01-01

    The Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the FBN1 gene.Recent molecular studies,most performed in mouse models,revealed that the MFS is more a developmental abnormality with broad and complex effects on the morphogenesis and function of multiple organ systems.FBN1 haploinsufficiency and dysregulated transforming growth factor-beta (TGF-β)signaling seem to be critical for clinical manifestations in MFS including aortic root dilatation.Aortic root aneurysm and aortic dissection represent the main causes of morbidity and mortality in MFS.Most importantly,TGF-β antagonism through angiotensin Ⅱ type 1 receptor blockers (ARBs),for example losartan,has been shown to prevent and possibly reverse aortic root dilatation in a mouse model of MFS.A first human study on a small pediatric cohort confirmed those promising results in reducing the aortic root growth over a follow-up period of 12 to 47 months.So,a large multicenter trial has been set up and results should be available soon.Other therapeutic strategies which might be combined with losartan include traditional β-blockade,doxycyclin and statins.Such management could offer the first potential for primary prevention of clinical manifestations in MFS.

  12. Novel pharmacological strategies to prevent aortic complications in Marfan syndrome.

    Science.gov (United States)

    Matt, Peter; Eckstein, Friedrich

    2011-12-01

    The Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the FBN1 gene. Recent molecular studies, most performed in mouse models, revealed that the MFS is more a developmental abnormality with broad and complex effects on the morphogenesis and function of multiple organ systems. FBN1 haploinsufficiency and dysregulated transforming growth factor-beta (TGF-β) signaling seem to be critical for clinical manifestations in MFS including aortic root dilatation. Aortic root aneurysm and aortic dissection represent the main causes of morbidity and mortality in MFS. Most importantly, TGF-β antagonism through angiotensin II type 1 receptor blockers (ARBs), for example losartan, has been shown to prevent and possibly reverse aortic root dilatation in a mouse model of MFS. A first human study on a small pediatric cohort confirmed those promising results in reducing the aortic root growth over a follow-up period of 12 to 47 months. So, a large multicenter trial has been set up and results should be available soon. Other therapeutic strategies which might be combined with losartan include traditional β-blockade, doxycyclin and statins. Such management could offer the first potential for primary prevention of clinical manifestations in MFS. PMID:22783312

  13. Midterm Results of Aortic Valve Replacement with Cryopreserved Homografts

    Directory of Open Access Journals (Sweden)

    Emre Özker

    2012-06-01

    Full Text Available Objective: The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.Materials and Methods: Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%, truncus arteriosus in 6 patients (15%, and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35% patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.Results: The 30-day postoperative mortality rate was 12.5% (5 patients. There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003. The last follow up showed that the 27 (82% patients had a normal left ventricular function.Conclusion: Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

  14. Effect of candesartan treatment on left ventricular remodeling after aortic valve replacement for aortic stenosis

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Videbaek, Lars; Poulsen, Mikael K;

    2010-01-01

    group had greater improvement in longitudinal LV systolic function assessed by tissue Doppler S' wave (0.6 +/- 0.1-cm/s increase in control group vs 1.4 +/- 0.1 cm/s in candesartan group, p = 0.01, p for trend = 0.02) and a decrease in LA volume (p for trend = 0.01). Treatment had no effect on diastolic......In hypertension, angiotensin receptor blockers can augment regression of left ventricular (LV) hypertrophy. It is not known whether this also is the case after aortic valve replacement (AVR) for severe aortic stenosis (AS). To test the hypothesis that treatment with candesartan in addition...... to conventional treatment is able to augment LV and left atrial (LA) reverse remodeling in patients with AS undergoing AVR, we studied 114 patients scheduled for AVR. Patients were randomized to treatment with candesartan 32 mg 1 time/day or conventional therapy immediately after AVR. Patients were followed...

  15. Quadricuspid aortic valve complicated with infective endocarditis: report of a case.

    Science.gov (United States)

    Mizoguchi, Hiroki; Sakaki, Masayuki; Inoue, Kazushige; Kobayashi, Yasuhiko; Iwata, Takashi; Suehiro, Yasuo; Miura, Takuya

    2014-12-01

    Congenital quadricuspid aortic valve is a rare cardiac malformation with an unknown risk of infective endocarditis. We report a case of quadricuspid aortic valve complicated with infective endocarditis. A 53-year-old Japanese woman was hospitalized with leg edema and a fever of unknown origin. Corynebacterium striatum was detected in the blood culture. Echocardiography demonstrated a quadricuspid aortic valve with vegetation and severe functional regurgitation. The condition was diagnosed as a quadricuspid aortic valve with infective endocarditis, for which surgery was performed. The quadricuspid aortic valve had three equal-sized cusps and one smaller cusp (type B according to Hurwitz classification). We dissected the vegetation and infectious focus and implanted a mechanical valve. Following the case report, we review the literature.

  16. Shape-based diagnosis of the aortic valve

    Science.gov (United States)

    Ionasec, Razvan Ioan; Tsymbal, Alexey; Vitanovski, Dime; Georgescu, Bogdan; Zhou, S. Kevin; Navab, Nassir; Comaniciu, Dorin

    2009-02-01

    Disorders of the aortic valve represent a common cardiovascular disease and an important public-health problem worldwide. Pathological valves are currently determined from 2D images through elaborate qualitative evalu- ations and complex measurements, potentially inaccurate and tedious to acquire. This paper presents a novel diagnostic method, which identies diseased valves based on 3D geometrical models constructed from volumetric data. A parametric model, which includes relevant anatomic landmarks as well as the aortic root and lea ets, represents the morphology of the aortic valve. Recently developed robust segmentation methods are applied to estimate the patient specic model parameters from end-diastolic cardiac CT volumes. A discriminative distance function, learned from equivalence constraints in the product space of shape coordinates, determines the corresponding pathology class based on the shape information encoded by the model. Experiments on a heterogeneous set of 63 patients aected by various diseases demonstrated the performance of our method with 94% correctly classied valves.

  17. Impact of Endografting on the Thoracic Aortic Anatomy: Comparative Analysis of the Aortic Geometry before and after the Endograft Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Midulla, Marco, E-mail: marco.midulla@chru-lille.fr [University Hospital of Lille, Cardiovascular and Interventional Radiology (France); Moreno, Ramiro, E-mail: ramoroa@gmail.com [Rangueil University Hospital, Department of Radiology (France); Negre-Salvayre, Anne, E-mail: anne.negre-salvayre@inserm.fr [INSERM, UMR 1048, I2MC (France); Nicoud, Franc, E-mail: franck.nicoud@univ-montp2.fr [CNRS, UMR 5149 I3M, CC 051, University Montpellier II (France); Pruvo, Jean Pierre, E-mail: jean-pierre.pruvo@chru-lille.fr [University Hospital of Lille, Cardiovascular and Interventional Radiology (France); Haulon, Stephan, E-mail: stephan.haulon@chru-lille.fr [University Hospital of Lille, Department of Vascular Surgery (France); Rousseau, Hervé, E-mail: rousseau.h@chu-toulouse.fr [Rangueil University Hospital, Department of Radiology (France)

    2013-03-13

    PurposeAlthough the widespread acceptance of thoracic endovascular aortic repair (TEVAR) as a first-line treatment option for a multitude of thoracic aortic diseases, little is known about the consequences of the device implantation on the native aortic anatomy. We propose a comparative analysis of the pre- and postoperative geometry on a clinical series of patients and discuss the potential clinical implicationsMethodsCT pre- and postoperative acquisitions of 30 consecutive patients treated by TEVAR for different pathologies (20 thoracic aortic aneurysms, 6 false aneurysms, 3 penetrating ulcers, 1 traumatic rupture) were used to model the vascular geometry. Pre- and postoperative geometries were compared for each patient by pairing and matching the 3D models. An implantation site was identified, and focal differences were detected and described.ResultsSegmentation of the data sets was successfully performed for all 30 subjects. Geometry differences between the pre- and postoperative meshes were depicted in 23 patients (76 %). Modifications at the upper implantation site were detected in 14 patients (47 %), and among them, the implantation site involved the arch (Z0–3) in 11 (78 %).ConclusionModeling the vascular geometry on the basis of imaging data offers an effective tool to perform patient-specific analysis of the vascular geometry before and after the treatment. Future studies will evaluate the consequences of these changes on the aortic function.

  18. Acute aortic valve prolapse in Marfan's syndrome.

    OpenAIRE

    Carr, N J; Cullen, S. A.

    1991-01-01

    A 22 year old man with Marfan's syndrome died suddenly following acute aortic valve prolapse. Although aortic root involvement in Marfan's syndrome is common, we have found no previous description of this particular complication in the literature.

  19. Evaluating the feasibility of an agglomerative hierarchy clustering algorithm for the automatic detection of the arterial input function using DSC-MRI.

    Directory of Open Access Journals (Sweden)

    Jiandong Yin

    Full Text Available During dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI, it has been demonstrated that the arterial input function (AIF can be obtained using fuzzy c-means (FCM and k-means clustering methods. However, due to the dependence on the initial centers of clusters, both clustering methods have poor reproducibility between the calculation and recalculation steps. To address this problem, the present study developed an alternative clustering technique based on the agglomerative hierarchy (AH method for AIF determination. The performance of AH method was evaluated using simulated data and clinical data based on comparisons with the two previously demonstrated clustering-based methods in terms of the detection accuracy, calculation reproducibility, and computational complexity. The statistical analysis demonstrated that, at the cost of a significantly longer execution time, AH method obtained AIFs more in line with the expected AIF, and it was perfectly reproducible at different time points. In our opinion, the disadvantage of AH method in terms of the execution time can be alleviated by introducing a professional high-performance workstation. The findings of this study support the feasibility of using AH clustering method for detecting the AIF automatically.

  20. Image derived input function for [18F]-FEPPA: application to quantify translocator protein (18 kDa in the human brain.

    Directory of Open Access Journals (Sweden)

    Rostom Mabrouk

    Full Text Available In [18F]-FEPPA positron emission topography (PET imaging, automatic blood sampling system (ABSS is currently the gold standard to obtain the blood time activity curve (TAC required to extract the input function (IF. Here, we compare the performance of two image-based methods of IF extraction to the ABSS gold standard method for the quantification of translocator protein (TSPO in the human brain. The IFs were obtained from a direct delineation of the internal carotid signal (CS and a new concept of independent component analysis (ICA. PET scans were obtained from 18 healthy volunteers. The estimated total distribution volume (V(T by CS-IF and ICA-IF were compared to the reference V(T obtained by ABSS-IF in the frontal and temporal cortex, cerebellum, striatum and thalamus regions. The V(T values estimated using ICA-IF were more reliable than CS-IF for all brain regions. Specifically, the slope regression in the frontal cortex with ICA-IF was r² = 0.91 (p<0.05, and r² = 0.71 (p<0.05 using CS-IF.

  1. Arterial input function of an optical tracer for dynamic contrast enhanced imaging can be determined from pulse oximetry oxygen saturation measurements

    Science.gov (United States)

    Elliott, Jonathan T.; Wright, Eric A.; Tichauer, Kenneth M.; Diop, Mamadou; Morrison, Laura B.; Pogue, Brian W.; Lee, Ting-Yim; St. Lawrence, Keith

    2012-12-01

    In many cases, kinetic modeling requires that the arterial input function (AIF)—the time-dependent arterial concentration of a tracer—be characterized. A straightforward method to measure the AIF of red and near-infrared optical dyes (e.g., indocyanine green) using a pulse oximeter is presented. The method is motivated by the ubiquity of pulse oximeters used in both preclinical and clinical applications, as well as the gap in currently available technologies to measure AIFs in small animals. The method is based on quantifying the interference that is observed in the derived arterial oxygen saturation (SaO2) following a bolus injection of a light-absorbing dye. In other words, the change in SaO2 can be converted into dye concentration knowing the chromophore-specific extinction coefficients, the true arterial oxygen saturation, and total hemoglobin concentration. A simple error analysis was performed to highlight potential limitations of the approach, and a validation of the method was conducted in rabbits by comparing the pulse oximetry method with the AIF acquired using a pulse dye densitometer. Considering that determining the AIF is required for performing quantitative tracer kinetics, this method provides a flexible tool for measuring the arterial dye concentration that could be used in a variety of applications.

  2. Arterial input function calculation in dynamic contrast-enhanced MRI: an in vivo validation study using co-registered contrast-enhanced ultrasound imaging

    International Nuclear Information System (INIS)

    Developing a method of separating intravascular contrast agent concentration to measure the arterial input function (AIF) in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of tumours, and validating its performance in phantom and in vivo experiments. A tissue-mimicking phantom was constructed to model leaky tumour vasculature and DCE-MR images of this phantom were acquired. An in vivo study was performed using tumour-bearing rabbits. Co-registered DCE-MRI and contrast-enhanced ultrasound (CEUS) images were acquired. An independent component analysis (ICA)-based method was developed to separate the intravascular component from DCE-MRI. Results were validated by comparing the time-intensity curves with the actual phantom and in vivo curves. Phantom study: the AIF extracted using ICA correlated well with the true intravascular curve. In vivo study: the AIFs extracted from DCE-MRI using ICA were very close to the true AIF. Intravascular component images were very similar to the CEUS images. The contrast onset times and initial wash-in slope of the ICA-derived AIF showed good agreement with the CEUS curves. ICA has the potential to separate the intravascular component from DCE-MRI. This could eliminate the requirement for contrast medium uptake measurements in a major artery and potentially result in more accurate pharmacokinetic parameters. (orig.)

  3. ABDOMINAL AORTIC ANEURYSM (AAA

    Directory of Open Access Journals (Sweden)

    Rajesh G

    2011-11-01

    Full Text Available AAA is defined as a distension of the infrarenal aorta by more than 50% (or 1.5 times compared with a corresponding healthy, aged and gender matched population. AAA afflicts 1 to 6 % of the general population aged more than 60 years and the incidence rises by approximately 0.15% annually. When the definition of a maximum external diameter ≥3 cm is used, the prevalence of AAA is upto 6 times greater in men than in women. AAAs are much more common than thoracic aortic aneurysms. Most common cause of AAA is atherosclerosis (95%. Less common causes include infectious or inflammatory origin or those associated with connective tissue disorders. Process of AAA formation is multifactorial. Other than the general risk factors for atherosclerosis, genetic predispo s iti on, aut o immunity and hemodynamic factors all play roles in its formation. AAA is 1.5 times more frequent in hypert ensive patients. Smokers have 8 times risk for developing AAA. The existence of familial aggre gation of AAA implicates genetic factors in the etiology of AAA. Women with AAA are more likely to have a positive family history of this disorder. Those with a family history of AAA have an increased risk of 30%, and their aneurysms tend to occur at a younger age and carry a greater risk of rupture than do sporadic aneurysms.

  4. Abdominal aortic feminism.

    Science.gov (United States)

    Mortimer, Alice Emily

    2014-01-01

    A 79-year-old woman presented to a private medical practice 2 years previously for an elective ultrasound screening scan. This imaging provided the evidence for a diagnosis of an abdominal aortic aneurysm (AAA) to be made. Despite having a number of recognised risk factors for an AAA, her general practitioner at the time did not follow the guidance set out by the private medical professional, that is, to refer the patient to a vascular specialist to be entered into a surveillance programme and surgically evaluated. The patient became symptomatic with her AAA, was admitted to hospital and found to have a tender, symptomatic, 6 cm leaking AAA. She consented for an emergency open AAA repair within a few hours of being admitted to hospital, despite the 50% perioperative mortality risk. The patient spent 4 days in intensive care where she recovered well. She was discharged after a 12 day hospital stay but unfortunately passed away shortly after her discharge from a previously undiagnosed gastric cancer.

  5. Open aortic surgery after thoracic endovascular aortic repair.

    Science.gov (United States)

    Coselli, Joseph S; Spiliotopoulos, Konstantinos; Preventza, Ourania; de la Cruz, Kim I; Amarasekara, Hiruni; Green, Susan Y

    2016-08-01

    In the last decade, thoracic endovascular aortic aneurysm repair (TEVAR) has emerged as an appealing alternative to the traditional open aortic aneurysm repair. This is largely due to generally improved early outcomes associated with TEVAR, including lower perioperative mortality and morbidity. However, it is relatively common for patients who undergo TEVAR to need a secondary intervention. In select circumstances, these secondary interventions are performed as an open procedure. Although it is difficult to assess the rate of open repairs after TEVAR, the rates in large series of TEVAR cases (>300) have ranged from 0.4 to 7.9 %. Major complications of TEVAR that typically necessitates open distal aortic repair (i.e., repair of the descending thoracic or thoracoabdominal aorta) include endoleak (especially type I), aortic fistula, endograft infection, device collapse or migration, and continued expansion of the aneurysm sac. Conversion to open repair of the distal aorta may be either elective (as for many endoleaks) or emergent (as for rupture, retrograde complicated dissection, malperfusion, and endograft infection). In addition, in select patients (e.g., those with a chronic aortic dissection), unrepaired sections of the aorta may progressively dilate, resulting in the need for multiple distal aortic repairs. Open repairs after TEVAR can be broadly classified as full extraction, partial extraction, or full salvage of the stent-graft. Although full and partial stent-graft extraction imply failure of TEVAR, such failure is generally absent in cases where the stent-graft can be fully salvaged. We review the literature regarding open repair after TEVAR and highlight operative strategies.

  6. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    DEFF Research Database (Denmark)

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars;

    2014-01-01

    BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS......: We retrospectively collected baseline characteristics, procedural data, and clinical follow-up findings from 12 centers in Europe and Canada that had performed TAV-in-BAV. RESULTS: A total of 139 patients underwent TAV-in-BAV with the balloon-expandable transcatheter heart valve (THV) (n = 48...

  7. Two-source interference as the major reason for auditory-threshold estimation error based on DPOAE input-output functions in normal-hearing subjects.

    Science.gov (United States)

    Dalhoff, Ernst; Turcanu, Diana; Vetešník, Aleš; Gummer, Anthony W

    2013-02-01

    Fine structure in the frequency response of distortion product otoacoustic emissions (DPOAEs) can severely limit the usefulness of DPOAEs in estimating auditory thresholds. Here, fine structure is removed by extracting the primary-source DPOAE component using the onset-decomposition technique (Vetešník et al., 2009) and auditory threshold estimates are compared to those obtained from DPOAEs in response to conventional, continuous two-tone stimulation. Auditory thresholds are predicted using the estimated distortion product thresholds (EDPTs), obtained from linear regression of input-output (I/O) functions of DPOAE pressure amplitude versus second-tone stimulus level (Boege and Janssen, 2002). The accuracy of the auditory-threshold predictions is derived by comparison with measured auditory thresholds. The parameters of the two primary stimulus tones of frequency f(1) and f(2) and levels of L(1) and L(2) are chosen as: f(2)/f(1) = 1.2 with 1.5 ≤ f(2) ≤ 2.5 kHz, and L(1) = 0.4L(2) + 39 dB SPL, with 25 ≤ L(2) ≤ 65 dB SPL. Data are from 12 normal-hearing subjects with profound DPOAE fine structure. 255 DPOAE I/O functions were measured for each of the two DPOAE paradigms. An EDPT value was accepted as reliable if: 1) the squared correlation coefficient, r(2) ≥ 0.8, 2) the regression slope, s(I/O) ≥ 0.2 μPa/dB, and 3) the standard deviation of the EDPT, σ(EDPT) ≤ 10 dB. The proportion of rejected I/O functions was 8% for onset-decomposition DPOAEs, and 25% for continuous-tone DPOAEs. Removal of data points from the saturation region of the DPOAE I/O function by an automated algorithm reduced the rejection rate, to zero for onset-decomposition DPOAEs, but to only 13% for continuous-tone DPOAEs. In the absence of saturated DPOAE responses, auditory thresholds were predicted with standard deviation of only 4 dB for onset-decomposition DPOAEs, but 12 dB for continuous-tone DPOAEs. In summary, by extracting the primary

  8. Input reallocation within firms

    OpenAIRE

    Vandenbussche, Hylke; Viegelahn, Christian

    2016-01-01

    This paper documents the within firm reallocation of inputs and outputs as a result of a trade policy shock on the input side. A unique firm-input level dataset for India with information on different raw material inputs used in production, enables us to identify firms with imported inputs subject to trade policy. To guide the empirics, we first develop a back-bone model of heterogeneous firms that source inputs from abroad. We find that affected firms engage in input reallocation and lower t...

  9. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR. PMID:27295772

  10. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR.

  11. A model-constrained Monte Carlo method for blind arterial input function estimation in dynamic contrast-enhanced MRI: II. In vivo results

    Science.gov (United States)

    Schabel, Matthias C.; DiBella, Edward V. R.; Jensen, Randy L.; Salzman, Karen L.

    2010-08-01

    Accurate quantification of pharmacokinetic model parameters in tracer kinetic imaging experiments requires correspondingly accurate determination of the arterial input function (AIF). Despite significant effort expended on methods of directly measuring patient-specific AIFs in modalities as diverse as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), dynamic positron emission tomography (PET), and perfusion computed tomography (CT), fundamental and technical difficulties have made consistent and reliable achievement of that goal elusive. Here, we validate a new algorithm for AIF determination, the Monte Carlo blind estimation (MCBE) method (which is described in detail and characterized by extensive simulations in a companion paper), by comparing AIFs measured in DCE-MRI studies of eight brain tumor patients with results of blind estimation. Blind AIFs calculated with the MCBE method using a pool of concentration-time curves from a region of normal brain tissue were found to be quite similar to the measured AIFs, with statistically significant decreases in fit residuals observed in six of eight patients. Biases between the blind and measured pharmacokinetic parameters were the dominant source of error. Averaged over all eight patients, the mean biases were +7% in K trans, 0% in kep, -11% in vp and +10% in ve. Corresponding uncertainties (median absolute deviation from the best fit line) were 0.0043 min-1 in K trans, 0.0491 min-1 in kep, 0.29% in vp and 0.45% in ve. The use of a published population-averaged AIF resulted in larger mean biases in three of the four parameters (-23% in K trans, -22% in kep, -63% in vp), with the bias in ve unchanged, and led to larger uncertainties in all four parameters (0.0083 min-1 in K trans, 0.1038 min-1 in kep, 0.31% in vp and 0.95% in ve). When blind AIFs were calculated from a region of tumor tissue, statistically significant decreases in fit residuals were observed in all eight patients despite larger

  12. Using The Descending Aortic Wall Thickness Measured In Transesophageal Echocardiography As A Risk Marker For Aortic Dissection

    OpenAIRE

    Zaher Fanari; Sumaya Hammami; Muhammad Baraa Hammami; Safa Hammami; Chete Eze-Nliam; Weintraub, William S.

    2015-01-01

    Objective: The aim of this study is to estimate whether aortic wall thickness is increased in patients with Aortic dissection (AD) compared to low risk control group and can be used in addition to aortic diameter as a risk marker of AD. Background: AD occurs due to pathologies that may increase thickness of the aortic wall. Transesophageal echocardiography (TEE) has the ability to visualise both the thoracic aortic wall and lumen. Aortic diameter has been used to predict aortic dissection...

  13. Corrections of arterial input function for dynamic H215O PET to assess perfusion of pelvic tumours: arterial blood sampling versus image extraction

    Science.gov (United States)

    Lüdemann, L.; Sreenivasa, G.; Michel, R.; Rosner, C.; Plotkin, M.; Felix, R.; Wust, P.; Amthauer, H.

    2006-06-01

    Assessment of perfusion with 15O-labelled water (H215O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 ± 52.0%) and lower partition coefficients (-31.6 ± 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF.

  14. Assessment of the arterial input function for estimation of coronary flow reserve by single photon emission computed tomography: comparison of two different approaches

    Energy Technology Data Exchange (ETDEWEB)

    Storto, Giovanni [IRCCS, CROB, Rionero in Vulture (Italy); Soricelli, Andrea [Institute of Diagnostic and Nuclear Development, SDN Foundation, Naples (Italy); Pellegrino, Teresa; Cuocolo, Alberto [Institute of Biostructures and Bioimages, National Council of Research, University Federico II, Department of Biomorphological and Functional Sciences, Naples (Italy); Petretta, Mario [University Federico II, Department of Clinical Medicine, Cardiovascular and Immunological Sciences, Naples (Italy)

    2009-12-15

    Attempts to estimate coronary flow reserve (CFR) with single photon emission computed tomography (SPECT) tracers have been recently made. We compared two different methods for the estimation of CFR by SPECT imaging. Fourteen patients with coronary artery disease underwent dipyridamole {sup 99m}Tc-sestamibi SPECT and intracoronary Doppler within 5 days. Myocardial blood flow (MBF) was estimated by measurement of first transit counts in the right pulmonary artery (PA) and left ventricular (LV) chamber, and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress MBF to rest MBF. Rest and stress MBF obtained using first transit counts from PA were higher compared to that from LV chamber (rest: 1.05 {+-} 0.38 vs 0.87 {+-} 0.34 counts/pixel per s, respectively, p < 0.01 and stress: 1.34 {+-} 0.45 vs 0.91 {+-} 0.20 counts/pixel per s, respectively, p < 0.05). In the study vessels, CFR by Doppler was 1.39 {+-} 0.42, and SPECT CFR obtained using first transit counts from PA and LV chamber were 1.36 {+-} 0.43 and 1.16 {+-} 0.39, respectively (p across categories NS). A significant relationship between SPECT CFR obtained using first transit counts from PA and CFR by Doppler was found (r = 0.85, p < 0.001). No relationship between SPECT CFR obtained using first transit counts from LV chamber and CFR by intracoronary Doppler was observed (r = 0.43, p = NS). SPECT-estimated CFR obtained using first transit counts from right PA is more accurate and correlates better with the results of intracoronary Doppler than estimated CFR obtained using arterial input function from LV chamber. (orig.)

  15. SU-C-18C-02: Specifcation of X-Ray Projection Angles Which Are Aligned with the Aortic Valve Plane From a Planar Image of a Valvuloplasty Balloon Inflated Across the Aortic Valve

    Energy Technology Data Exchange (ETDEWEB)

    Fetterly, K; Mathew, V [Mayo Clinic, Rochester, MN (United States)

    2014-06-01

    Purpose: Transcatheter aortic valve replacement (TAVR) procedures provide a method to implant a prosthetic aortic valve via a minimallyinvasive, catheter-based procedure. TAVR procedures require use of interventional fluoroscopy c-arm projection angles which are aligned with the aortic valve plane to minimize prosthetic valve positioning error due to x-ray imaging parallax. The purpose of this work is to calculate the continuous range of interventional fluoroscopy c-arm projection angles which are aligned with the aortic valve plane from a single planar image of a valvuloplasty balloon inflated across the aortic valve. Methods: Computational methods to measure the 3D angular orientation of the aortic valve were developed. Required inputs include a planar x-ray image of a known valvuloplasty balloon inflated across the aortic valve and specifications of x-ray imaging geometry from the DICOM header of the image. A-priori knowledge of the species-specific typical range of aortic orientation is required to specify the sign of the angle of the long axis of the balloon with respect to the x-ray beam. The methods were validated ex-vivo and in a live pig. Results: Ex-vivo experiments demonstrated that the angular orientation of a stationary inflated valvuloplasty balloon can be measured with precision less than 1 degree. In-vivo pig experiments demonstrated that cardiac motion contributed to measurement variability, with precision less than 3 degrees. Error in specification of x-ray geometry directly influences measurement accuracy. Conclusion: This work demonstrates that the 3D angular orientation of the aortic valve can be calculated precisely from a planar image of a valvuloplasty balloon inflated across the aortic valve and known x-ray geometry. This method could be used to determine appropriate c-arm angular projections during TAVR procedures to minimize x-ray imaging parallax and thereby minimize prosthetic valve positioning errors.

  16. SU-C-18C-02: Specifcation of X-Ray Projection Angles Which Are Aligned with the Aortic Valve Plane From a Planar Image of a Valvuloplasty Balloon Inflated Across the Aortic Valve

    International Nuclear Information System (INIS)

    Purpose: Transcatheter aortic valve replacement (TAVR) procedures provide a method to implant a prosthetic aortic valve via a minimallyinvasive, catheter-based procedure. TAVR procedures require use of interventional fluoroscopy c-arm projection angles which are aligned with the aortic valve plane to minimize prosthetic valve positioning error due to x-ray imaging parallax. The purpose of this work is to calculate the continuous range of interventional fluoroscopy c-arm projection angles which are aligned with the aortic valve plane from a single planar image of a valvuloplasty balloon inflated across the aortic valve. Methods: Computational methods to measure the 3D angular orientation of the aortic valve were developed. Required inputs include a planar x-ray image of a known valvuloplasty balloon inflated across the aortic valve and specifications of x-ray imaging geometry from the DICOM header of the image. A-priori knowledge of the species-specific typical range of aortic orientation is required to specify the sign of the angle of the long axis of the balloon with respect to the x-ray beam. The methods were validated ex-vivo and in a live pig. Results: Ex-vivo experiments demonstrated that the angular orientation of a stationary inflated valvuloplasty balloon can be measured with precision less than 1 degree. In-vivo pig experiments demonstrated that cardiac motion contributed to measurement variability, with precision less than 3 degrees. Error in specification of x-ray geometry directly influences measurement accuracy. Conclusion: This work demonstrates that the 3D angular orientation of the aortic valve can be calculated precisely from a planar image of a valvuloplasty balloon inflated across the aortic valve and known x-ray geometry. This method could be used to determine appropriate c-arm angular projections during TAVR procedures to minimize x-ray imaging parallax and thereby minimize prosthetic valve positioning errors

  17. Spectrum of Aortic Valve Abnormalities Associated with Aortic Dilation Across Age Groups in Turner Syndrome

    Science.gov (United States)

    Olivieri, Laura J.; Baba, Ridhwan Y.; Arai, Andrew E.; Bandettini, W. Patricia; Rosing, Douglas R.; Bakalov, Vladimir; Sachdev, Vandana; Bondy, Carolyn A.

    2014-01-01

    Background Congenital aortic valve fusion is associated with aortic dilation, aneurysm and rupture in girls and women with Turner syndrome (TS). Our objective was to characterize aortic valve structure in subjects with TS, and determine the prevalence of aortic dilation and valve dysfunction associated with different types of aortic valves. Methods and Results The aortic valve and thoracic aorta were characterized by cardiovascular magnetic resonance imaging in 208 subjects with TS in an IRB-approved natural history study. Echocardiography was used to measure peak velocities across the aortic valve, and the degree of aortic regurgitation. Four distinct valve morphologies were identified: tricuspid aortic valve (TAV) 64%(n=133), partially fused aortic valve (PF) 12%(n=25), bicuspid aortic valve (BAV) 23%(n=47), and unicuspid aortic valve (UAV) 1%(n=3). Age and body surface area (BSA) were similar in the 4 valve morphology groups. There was a significant trend, independent of age, towards larger BSA-indexed ascending aortic diameters (AADi) with increasing valve fusion. AADi were (mean +/− SD) 16.9 +/− 3.3 mm/m2, 18.3 +/− 3.3 mm/m2, and 19.8 +/− 3.9 mm/m2 (p<0.0001) for TAV, PF and BAV+UAV respectively. PF, BAV, and UAV were significantly associated with mild aortic regurgitation and elevated peak velocities across the aortic valve. Conclusions Aortic valve abnormalities in TS occur with a spectrum of severity, and are associated with aortic root dilation across age groups. Partial fusion of the aortic valve, traditionally regarded as an acquired valve problem, had an equal age distribution and was associated with an increased AADi. PMID:24084490

  18. Flexible and re-configurable optical three-input XOR logic gate of phase-modulated signals with multicast functionality for potential application in optical physical-layer network coding.

    Science.gov (United States)

    Lu, Guo-Wei; Qin, Jun; Wang, Hongxiang; Ji, XuYuefeng; Sharif, Gazi Mohammad; Yamaguchi, Shigeru

    2016-02-01

    Optical logic gate, especially exclusive-or (XOR) gate, plays important role in accomplishing photonic computing and various network functionalities in future optical networks. On the other hand, optical multicast is another indispensable functionality to efficiently deliver information in optical networks. In this paper, for the first time, we propose and experimentally demonstrate a flexible optical three-input XOR gate scheme for multiple input phase-modulated signals with a 1-to-2 multicast functionality for each XOR operation using four-wave mixing (FWM) effect in single piece of highly-nonlinear fiber (HNLF). Through FWM in HNLF, all of the possible XOR operations among input signals could be simultaneously realized by sharing a single piece of HNLF. By selecting the obtained XOR components using a followed wavelength selective component, the number of XOR gates and the participant light in XOR operations could be flexibly configured. The re-configurability of the proposed XOR gate and the function integration of the optical logic gate and multicast in single device offer the flexibility in network design and improve the network efficiency. We experimentally demonstrate flexible 3-input XOR gate for four 10-Gbaud binary phase-shift keying signals with a multicast scale of 2. Error-free operations for the obtained XOR results are achieved. Potential application of the integrated XOR and multicast function in network coding is also discussed. PMID:26906806

  19. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... more likely we see aortic stenosis. Again, patient education is part of the evaluation and management of ... want to embrace less invasive or more progressive technology, you want to make ... with that information and certainly shouldn't be insulted by that. ...

  20. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... well. I want to underscore again that exercise testing is really not recommended in patient with classic symptoms in severe aortic stenosis, as it's probably more stress than the patient's heart should have to undergo. Once again, serial evaluations, as with any chronic disease process, are ...

  1. Lowering plasma cholesterol levels halts progression of aortic valve disease in mice

    Science.gov (United States)

    Miller, Jordan D.; Weiss, Robert M.; Serrano, Kristine M.; Brooks, Robert M.; Berry, Christopher J.; Zimmerman, Kathy; Young, Stephen G.; Heistad, Donald D.

    2009-01-01

    Background Treatment of hyperlipidemia produces functional and structural improvements in atherosclerotic vessels. However, the effects of treating hyperlipidemia on the structure and function of the aortic valve has been controversial, and any effects could be confounded by pleiotropic effects of hypolipidemic treatment. The goal of this study was to determine whether reducing elevated plasma lipid levels with a “genetic switch” in Reversa mice (Ldlr−/−/Apob100/100/Mttpfl/fl/Mx1Cre+/+) reduces oxidative stress, reduces proosteogenic signaling, and retards the progression of aortic valve disease. Methods and Results After 6 months of hypercholesterolemia, Reversa mice exhibited increases in superoxide, lipid deposition, myofibroblast activation, calcium deposition, and pro-osteogenic protein expression in the aortic valve. Maximum aortic valve cusp separation, as judged by echocardiography, was not altered. During an additional 6 months of hypercholesterolemia, superoxide levels, valvular lipid deposition, and myofibroblast activation remained elevated. Furthermore, calcium deposition and pro-osteogenic gene expression became more pronounced and the aortic cusp separation decreased from 0.85 ± 0.04 to 0.70 ± 0.04 mm (mean ± SE; p < 0.05). Rapid normalization of cholesterol levels at 6 months of age (by inducing expression of Cre recombinase) normalized aortic valve superoxide levels, decreased myofibroblast activation, reduced valvular calcium burden, suppressed pro-osteogenic signaling cascades, and prevented the reductions in aortic valve cusp separation. Conclusions Collectively, these data indicate that reducing plasma lipid levels by genetic inactivation of the mttp gene in hypercholesterolemic mice with early aortic valve disease normalizes oxidative stress, reduces pro-osteogenic signaling, and halts the progression of aortic valve stenosis. PMID:19433756

  2. TART input manual

    International Nuclear Information System (INIS)

    The TART code is a Monte Carlo neutron/photon transport code that is only on the CRAY computer. All the input cards for the TART code are listed, and definitions for all input parameters are given. The execution and limitations of the code are described, and input for two sample problems are given

  3. TART input manual

    Energy Technology Data Exchange (ETDEWEB)

    Kimlinger, J.R.; Plechaty, E.F.

    1982-04-01

    The TART code is a Monte Carlo neutron/photon transport code that is only on the CRAY computer. All the input cards for the TART code are listed, and definitions for all input parameters are given. The execution and limitations of the code are described, and input for two sample problems are given. (WHK)

  4. Decreased expression of fibulin-4 in aortic wall of aortic dissection.

    Science.gov (United States)

    Huawei, P; Qian, C; Chuan, T; Lei, L; Laing, W; Wenlong, X; Wenzhi, L

    2014-02-01

    In this research, we will examine the expression of Fibulin-4 in aortic wall to find out its role in aortic dissection development. The samples of aortic wall were obtained from 10 patients operated for acute ascending aortic dissection and five patients for chronic ascending aortic dissection. Another 15 pieces of samples from patients who had coronary artery bypass were as controls. The aortic samples were stained with aldehyde magenta dyeing to evaluate the arrangement of elastic fibers. The Fibulin-4 protein and mRNA expression were both determined by Western blot and realtime quantitative polymerase chain reaction. Compared with the control group, both in acute and chronic ascending aortic dissection, elastic fiber fragments increased and the expression of fibulin-4 protein significantly decreased (P= 0.045 < 0.05). The level of fibulin-4 mRNA decreased in acute ascending aortic dissection (P= 0.034 < 0.05), while it increased in chronic ascending aortic dissection (P=0.004 < 0.05). The increased amounts of elastic fiber fragments were negatively correlated with the expression of fibulin-4 mRNA in acute ascending aortic dissection. In conclusion, in aortic wall of ascending aortic dissection, the expression of fibulin-4 protein decreased and the expression of fibulin-4 mRNA was abnormal. Fibulin-4 may play an important role in the pathogenesis of aortic dissection.

  5. Efectos del ejercicio isométrico sobre la función diastólica en pacientes con estenosis aortica severa Effect of isometric exercise on diastolic function in patients with severe aortic stenosis

    Directory of Open Access Journals (Sweden)

    M. Donato

    2003-01-01

    Full Text Available El objetivo del estudio fue determinar los efectos del ejercicio isométrico sobre la función diastólica, en pacientes con estenosis aórtica sin lesión coronaria (grupo 1, G2, n= 9 y con lesión coronaria (grupo 2, G2, n=11. Pacientes sometidos a un cateterismo cardíaco realizaron ejercicio isométrico hasta que la frecuencia cardíaca se incrementó un 32±9%, con respecto a su valor basal. Se midieron la presión sistólica ventricular izquierda (PSVI y la presión de fin de diástole (PDFVI y se calculó la constante de tiempo de caída de la presión ventricular (tau, t, y la máxima velocidad de ascenso de la presión (+dP/dt máx. La +dP/dt máx aumentó en G1 y G2, durante el ejercicio, desde un valor de 1989±190 y 2428±220 mmHg/seg, hasta un valor de 2286±214 y 2661±230 mmHg/seg, respectivamente; retornando luego a su valor basal. La PDFVI aumentó, durante el ejercicio, en G1 y G2 desde un valor de 30.1±2.7 y 26.5±2.2 mmHg hasta 38.4±1.7 y 36.1±4.0 mmHg, respectivamente (pThe objective of the study was to determine the effects of isometric exercise on the diastolic function in patients with aortic stenosis without coronary lesion (group 1, G1, n = 9 and with coronary lesion (group 2, G2, n=11. Patients subjected to a cardiac catheterization performed isometric exercise until their heart rate increased in 32±9 % compared to baseline. The left ventricular systolic pressure, the +dP/dt max, and the end diastolic pressure (LVEDP were measured, and the time constant of pressure decay (tau, t was calculated. The +dP/dt max increased in G1 and G2 during exercise, from a value of 1989±190 and 2428±220 mmHg/sec up to 2286±214 y 2661±230 mmHg/sec, respectively, returning afterwards to its baseline value. The LVEDP increased during exercise in G1 and G2 from a value of 30.1±2.7 and 26.5±2.2 mmHg up to 38.4±1.7 and 36.1±4.0 mmHg, respectively (p<0.05, returning to its baseline value only in G1. The tau (t increased during

  6. Growth hormone receptor deficiency in mice results in reduced systolic blood pressure and plasma renin, increased aortic eNOS expression, and altered cardiovascular structure and function

    DEFF Research Database (Denmark)

    Egecioglu, E; Andersson, I J; Bollano, E;

    2007-01-01

    To study the role of the growth hormone receptor (GHR) in the development of cardiovascular structure and function, female GHR gene-disrupted or knockout (KO) and wild-type (WT) mice at age 18 wk were used. GHR KO mice had lower plasma renin levels (12 +/- 2 vs. 20 +/- 4 mGU/ml, P ....05) in GHR KO. Relative left ventricular weight was 14% lower in GHR KO mice (P ... thickness was decreased in GHR KO (P KO mice, whereas the aorta of GHR KO mice showed an increased sensitivity...

  7. Biomarkers of Hemodynamic Stress and Aortic Stiffness after STEMI: A Cross-Sectional Analysis

    OpenAIRE

    Sebastian Johannes Reinstadler; Hans-Josef Feistritzer; Gert Klug; Agnes Mayr; Luc Huybrechts; Angelika Hammerer-Lercher; Johannes Mair; Wolfgang-Michael Franz; Bernhard Metzler

    2015-01-01

    Aim. Increased aortic stiffness might adversely affect cardiac structure, function, and perfusion. Release of biomarkers of hemodynamic stress is thought to be enhanced by these alterations. We aimed to evaluate the association between biomarkers of hemodynamic stress and aortic stiffness assessed at a chronic stage after ST-segment elevation myocardial infarction (STEMI). Methods. Fifty-four patients four months after STEMI were enrolled in this cross-sectional, single-center study. N-termin...

  8. Transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis: a meta analysis

    Institute of Scientific and Technical Information of China (English)

    WU Yi-cheng; ZHANG Jian-feng; SHEN Wei-feng; ZHAO Qiang

    2013-01-01

    Background Transcatheter aortic valve implantation (TAVI) has emerged as the treatment choice for non-operable patients with severe symptomatic aortic stenosis (AS) and may be a good alternative to surgery for those at very high or prohibitive surgical risk.We performed a meta-analysis to evaluate the comparative benefits of TAVI versus surgical aortic valve replacement (SAVR) in patients with severe AS.Methods A comprehensive literature search of PubMed,Embase,ScienceDirect and Cochrane Central Register of Controlled trials was performed,and randomized trials as well as cohort studies with propensity score analysis were included.Results One randomized trial (n=699) and six retrospective cohort studies (n=781) were selected for meta-analysis.Mortality at 30-day and 1-year follow-up was comparable between TAVI and SAVR.Despite similar incidences of stroke,myocardial infarction,re-operation for bleeding,and renal failure requiring dialysis,TAVI was associated with a lower occurrence rate of new-onset atrial fibrillation (OR 0.51,95% CI 0.33-0.78) and shorter procedural time (mean difference -67.50 minutes,95% CI-87.20 to-47.81 minutes).Post-operative aortic regurgitation and permanent pacemaker implantation were more common in patients after TAVI than in those with SAVR (OR 5.53,95% CI 3.41-8.97; OR 1.71,95% Cl 1.02-2.84,respectively).Conclusion In patients with severe symptomatic AS,TAVI and SAVR did not differ with respect to short-and mid-term survival,but the incidence of permanent pacemaker implantation and post-procedural aortic regurgitation remain relatively high after TAVI.

  9. Comprehensive Population-Averaged Arterial Input Function for Dynamic Contrast–Enhanced vMagnetic Resonance Imaging of Head and Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Onxley, Jennifer D.; Yoo, David S. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Muradyan, Naira [iCAD Inc., Nashua, New Hampshire (United States); MacFall, James R. [Department of Radiology, Duke University Medical Center, Durham, North Carolina (United States); Brizel, David M. [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Department of Surgery, Duke University Medical Center, Durham, North Carolina (United States); Craciunescu, Oana I., E-mail: Oana.Craciunescu@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States)

    2014-07-01

    Purpose: To generate a population-averaged arterial input function (PA-AIF) for quantitative analysis of dynamic contrast-enhanced MRI data in head and neck cancer patients. Methods and Materials: Twenty patients underwent dynamic contrast-enhanced MRI during concurrent chemoradiation therapy. Imaging consisted of 2 baseline scans 1 week apart (B1/B2) and 1 scan after 1 week of chemoradiation therapy (Wk1). Regions of interest (ROIs) in the right and left carotid arteries were drawn on coronal images. Plasma concentration curves of all ROIs were averaged and fit to a biexponential decay function to obtain the final PA-AIF (AvgAll). Right-sided and left-sided ROI plasma concentration curves were averaged separately to obtain side-specific AIFs (AvgRight/AvgLeft). Regions of interest were divided by time point to obtain time-point-specific AIFs (AvgB1/AvgB2/AvgWk1). The vascular transfer constant (K{sub trans}) and the fractional extravascular, extracellular space volume (V{sub e}) for primaries and nodes were calculated using the AvgAll AIF, the appropriate side-specific AIF, and the appropriate time-point-specific AIF. Median K{sub trans} and V{sub e} values derived from AvgAll were compared with those obtained from the side-specific and time-point-specific AIFs. The effect of using individual AIFs was also investigated. Results: The plasma parameters for AvgAll were a{sub 1,2} = 27.11/17.65 kg/L, m{sub 1,2} = 11.75/0.21 min{sup −1}. The coefficients of repeatability (CRs) for AvgAll versus AvgLeft were 0.04 min{sup −1} for K{sub trans} and 0.02 for V{sub e}. For AvgAll versus AvgRight, the CRs were 0.08 min{sup −1} for K{sub trans} and 0.02 for V{sub e}. When AvgAll was compared with AvgB1/AvgB2/AvgWk1, the CRs were slightly higher: 0.32/0.19/0.78 min{sup −1}, respectively, for K{sub trans}; and 0.07/0.08/0.09 for V{sub e}. Use of a PA-AIF was not significantly different from use of individual AIFs. Conclusion: A PA-AIF for head and neck cancer

  10. Indexing aortic valve area by body surface area increases the prevalence of severe aortic stenosis

    DEFF Research Database (Denmark)

    Jander, Nikolaus; Gohlke-Bärwolf, Christa; Bahlmann, Edda;

    2014-01-01

    To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are......To account for differences in body size in patients with aortic stenosis, aortic valve area (AVA) is divided by body surface area (BSA) to calculate indexed AVA (AVAindex). Cut-off values for severe stenosis are...

  11. Congenital aortic regurgitation in a child with a tricuspid non-stenotic aortic valve.

    OpenAIRE

    Hashimoto, R; Miyamura, H; Eguchi, S

    1984-01-01

    After follow up for seven years a 10 year old boy with congenital aortic regurgitation was found to have a tricuspid non-stenotic aortic valve at operation. The right coronary cusp was dysplastic, thickened, and contracted; the gap between its free margin and aortic wall was bridged with two fibrous bands; and the left coronary and non-coronary cusps were almost normal. The aortic valve was replaced with a prosthesis (St Jude Medical No 23), and the postoperative course was uneventful.

  12. Characterization of human aortic elastase found in patients with abdominal aortic aneurysms.

    Science.gov (United States)

    Cohen, J R; Mandell, C; Wise, L

    1987-10-01

    Recent evidence indicates that the homeostatic balance between elastase and antiprotease activity is altered in the infrarenal aorta of those patients with different types of aortic pathologic findings. The specific properties of elastase found in the aorta of patients with abdominal aortic aneurysms (AAA) are discussed herein. Activity of elastase extracted from ten pooled AAA specimens was observed when incubated with several inhibitors: 13.2 per cent for phenyl-suphonyl flouride (PSF); 43.3 per cent for ethylenediaminetetraacetic acid (EDTA); 77.7 per cent for pepstatin; 137.0 per cent for leupeptin, and 24.0 per cent for alpha-1-antitrypsin. Irreversible inhibition by PSF indicates that the elastase is a serine protease. The elastase is most likely not a metallo enzyme, since it had no absolute requirement for divalent cations as indicated by only partial inhibition by EDTA. Elastase activity is most likely not due to cathepsins B or D, since cathepsins are active in an acid pH and selectively inhibited by leupeptin and pepstatin. The pH curve revealed a maximum activity at pH 8.2 and elastase activity was significantly inhibited by alpha-1-antitrypsin in a dose response manner determining functional elastase activity. These data indicate that the elastase in the aorta of patients with an AAA has the exact properties of the serine elastase found in the smooth muscle cells of the aorta in rats. These results also confirm the critical role of alpha-1-antitrypsin in determining functional elastase activity. Smooth muscle cell regulation of elastin metabolism may be important in determining why some patients have AAA and others have occlusive aortic disease develop.

  13. Reference Values for Cardiac and Aortic Magnetic Resonance Imaging in Healthy, Young Caucasian Adults

    Science.gov (United States)

    Eikendal, Anouk L. M.; Bots, Michiel L.; Haaring, Cees; Saam, Tobias; van der Geest, Rob J.; Westenberg, Jos J. M.; den Ruijter, Hester M.; Hoefer, Imo E.; Leiner, Tim

    2016-01-01

    Background Reference values for morphological and functional parameters of the cardiovascular system in early life are relevant since they may help to identify young adults who fall outside the physiological range of arterial and cardiac ageing. This study provides age and sex specific reference values for aortic wall characteristics, cardiac function parameters and aortic pulse wave velocity (PWV) in a population-based sample of healthy, young adults using magnetic resonance (MR) imaging. Materials and Methods In 131 randomly selected healthy, young adults aged between 25 and 35 years (mean age 31.8 years, 63 men) of the general-population based Atherosclerosis-Monitoring-and-Biomarker-measurements-In-The-YOuNg (AMBITYON) study, descending thoracic aortic dimensions and wall thickness, thoracic aortic PWV and cardiac function parameters were measured using a 3.0T MR-system. Age and sex specific reference values were generated using dedicated software. Differences in reference values between two age groups (25–30 and 30–35 years) and both sexes were tested. Results Aortic diameters and areas were higher in the older age group (all p<0.007). Moreover, aortic dimensions, left ventricular mass, left and right ventricular volumes and cardiac output were lower in women than in men (all p<0.001). For mean and maximum aortic wall thickness, left and right ejection fraction and aortic PWV we did not observe a significant age or sex effect. Conclusion This study provides age and sex specific reference values for cardiovascular MR parameters in healthy, young Caucasian adults. These may aid in MR guided pre-clinical identification of young adults who fall outside the physiological range of arterial and cardiac ageing. PMID:27732640

  14. Aortopathy in patients with a bicuspid aortic valve : determining susceptibility for aortic complications

    NARCIS (Netherlands)

    Grewal, Nimrat

    2015-01-01

    The prevalence of aortic dilation and related complications as rupture and dissection is higher in patients with a bicuspid aortic valve (BAV) as compared to patients with a tricuspid aortic valve (TAV), although not every individual carries this increased risk. It is therefore essential to identify

  15. The Efficacy of Autologous Femoropopliteal Vein Reconstruction for Primary Aortic and Aortic Graft Infection

    NARCIS (Netherlands)

    Dirven, M.; Jagt, M.F.P. van der; Barendregt, W.B.; Vliet, D. van der

    2015-01-01

    BACKGROUND: The objective of our study was to analyze the efficacy of autologous superficial femoropopliteal vein reconstruction for primary aortic or aortic graft infection. METHODS: We performed a retrospective analysis of 14 patients treated for an infected aortic prosthesis or primary infected a

  16. Transcatheter valve-in-valve implantation due to severe aortic regurgitation in a degenerated aortic homograft

    DEFF Research Database (Denmark)

    Olsen, Lene Kjaer; Engstrøm, Thomas; Søndergaard, Lars

    2009-01-01

    a successful valve-in-valve implantation of a CoreValve aortic valve prosthesis through the right subclavian artery in a case of severe aortic regurgitation within a degenerated aortic homograft. The case exemplifies the possibilities of expanding the indications for TAVI, as well as other vascular access...

  17. New-Onset Atrial Fibrillation After Surgical Aortic Valve Replacement and Transcatheter Aortic Valve Implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav;

    2015-01-01

    Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...

  18. New-onset atrial fibrillation after surgical aortic valve replacement and transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Jørgensen, Troels Højsgaard; Thygesen, Julie Bjerre; Thyregod, Hans Gustav;

    2015-01-01

    Surgical aortic valve replacement (SAVR) and, more recently, transcatheter aortic valve implantation (TAVI) have been shown to be the only treatments that can improve the natural cause of severe aortic valve stenosis. However, after SAVR and TAVI, the incidence of new-onset atrial fibrillation...

  19. MARFAN SYNDROME AND QUADRICUSPID AORTIC VALVE

    OpenAIRE

    Sürücü, Hüseyin; ÇİMEN, Sadi

    2013-01-01

    ABSTRACTWhile the major cardiovascular manifestation in Marfan syndrome is a progressive dilatation of the ascending aorta, leading to aortic aneurysm formation and eventually to fatal aortic rupture or dissection, mitral valve prolapse and calcification of the mitral valve annulus, dilatation of the main pulmonary artery may be seen. There was no knowledge about the association of Marfan syndrome and quadricuspid aortic valve. In this case report, we aimed to declare this association between...

  20. Hybrid treatment of penetrating aortic ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Juan Antonio Herrero; Martins-Romeo, Daniela de Araujo; Escudero, Carlos Caparros; Falcon, Maria del Carmen Prieto; Batista, Vinicius Bianchi, E-mail: jaherrero5@hotmail.com [Unidade de Gestao Clinica (UGC) de Diagnostico por Imagem - Hosppital Universitario Virgen Macarena, Sevilha (Spain); Vazquez, Rosa Maria Lepe [Unit of Radiodiagnosis - Hospital Nuestra Senora de la Merced, Osuna, Sevilha (Spain)

    2015-05-15

    Penetrating atherosclerotic aortic ulcer is a rare entity with poor prognosis in the setting of acute aortic syndrome. In the literature, cases like the present one, located in the aortic arch, starting with chest pain and evolving with dysphonia, are even rarer. The present report emphasizes the role played by computed tomography in the diagnosis of penetrating atherosclerotic ulcer as well as in the differentiation of this condition from other acute aortic syndromes. Additionally, the authors describe a new therapeutic approach represented by a hybrid endovascular surgical procedure for treatment of the disease. (author)

  1. Abdominal Aortic Surgery: Anesthetic Implications

    OpenAIRE

    Cunningham, Anthony J.

    1991-01-01

    The objectives of the review are to highlight the clinical characteristics of the patient population; to assess multivariate risk factor analysis and the invasive/non-invasive techniques available for risk factor identification and management in this high-risk surgical population; to assess the major hemodynamic, metabolic, and regional blood flow changes associated with aortic cross-clamping/unclamping procedures and techniques for their modification or attenuation; and to assess the influen...

  2. Repair of recurrent pseudoaneurysm of the mitral-aortic intervalvular fibrosa: Role of transesophageal echocardiography

    Directory of Open Access Journals (Sweden)

    Shreedhar S Joshi

    2014-01-01

    Full Text Available Pseudoaneurysm of mitral-aortic intervalvular fibrosa (P-MAIVF is a rare cardiac surgical condition. P-MAIVF commonly occurs as a complication of aortic and mitral valve replacement surgeries. The surgical trauma during replacement of the valves weakens the avascular mitral and aortic intervalvular area. We present a case of P-MAIVF recurrence 5 years after a primary repair. Congestive cardiac failure was the presenting feature with mitral and aortic regurgitation. In view of the recurrence, the surgical team planned for a double valve replacement. The sewing rings of the two prosthetic-valves were interposed to close the mouth of the pseudoaneurysm and to provide mechanical reinforcement of the MAIVF. Intra-operative transesophageal echocardiography (TEE helped in delineating the anatomy, extent of the lesion, rupture of one of the pseudoaneurysm into left atrium and severity of the valvular regurgitation. Post-procedure TEE confirmed complete obliteration of the pseudoaneurysm and prosthetic valve function.

  3. Transcatheter aortic valve implantation of the direct flow medical aortic valve with minimal or no contrast

    Energy Technology Data Exchange (ETDEWEB)

    Latib, Azeem, E-mail: alatib@gmail.com [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Maisano, Francesco; Colombo, Antonio [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Klugmann, Silvio [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy); Low, Reginald; Smith, Thomas [University of California Davis, Davis, CA 95616 (United States); Davidson, Charles [Northwestern Memorial Hospital, Chicago, IL 60611 (United States); Harreld, John H. [Clinical Imaging Analytics, Guerneville, CA (United States); Bruschi, Giuseppe; DeMarco, Federico [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy)

    2014-06-15

    The 18F Direct Flow Medical (DFM) THV has conformable sealing rings, which minimizes aortic regurgitation and permits full hemodynamic assessment of valve performance prior to permanent implantation. During the DISCOVER trial, three patients who were at risk for receiving contrast media, two due to severe CKD and one due to a recent hyperthyroid reaction to contrast, underwent DFM implantation under fluoroscopic and transesophageal guidance without aortography during either positioning or to confirm the final position. Valve positioning was based on the optimal angiographic projection as calculated by the pre-procedural multislice CT scan. Precise optimization of valve position was performed to minimize transvalve gradient and aortic regurgitation. Prior to final implantation, transvalve hemodynamics were assessed invasively and by TEE. The post-procedure mean gradients were 7, 10, 11 mm Hg. The final AVA by echo was 1.70, 1.40 and 1.68 cm{sup 2}. Total aortic regurgitation post-procedure was none or trace in all three patients. Total positioning and assessment of valve performance time was 4, 6, and 12 minutes. Contrast was only used to confirm successful percutaneous closure of the femoral access site. The total contrast dose was 5, 8, 12 cc. Baseline eGFR and creatinine was 28, 22, 74 mL/min/1.73 m{sup 2} and 2.35, 2.98, and 1.03 mg/dL, respectively. Renal function was unchanged post-procedure: eGFR = 25, 35, and 96 mL/min/1.73 m{sup 2} and creatinine = 2.58, 1.99, and 1.03 mg/dL, respectively. In conclusion, the DFM THV provides the ability to perform TAVI with minimal or no contrast. The precise and predictable implantation technique can be performed with fluoro and echo guidance.

  4. Biomarkers of Hemodynamic Stress and Aortic Stiffness after STEMI: A Cross-Sectional Analysis

    Directory of Open Access Journals (Sweden)

    Sebastian Johannes Reinstadler

    2015-01-01

    Full Text Available Aim. Increased aortic stiffness might adversely affect cardiac structure, function, and perfusion. Release of biomarkers of hemodynamic stress is thought to be enhanced by these alterations. We aimed to evaluate the association between biomarkers of hemodynamic stress and aortic stiffness assessed at a chronic stage after ST-segment elevation myocardial infarction (STEMI. Methods. Fifty-four patients four months after STEMI were enrolled in this cross-sectional, single-center study. N-terminal pro–B-type natriuretic peptide (NT-proBNP, mid-regional pro–A-type natriuretic peptide (MR-proANP, and mid-regional proadrenomedullin (MR-proADM levels were measured by established assays. Aortic stiffness was assessed by the measurement of pulse wave velocity using phase-contrast cardiovascular magnetic resonance. Results. NT-proBNP, MR-proANP, and MR-proADM concentrations were all correlated with aortic stiffness in univariate analysis (r=0.378, r=0.425, and r=0.532; all P<0.005, resp.. In multiple linear regression analysis, NT-proBNP (β=0.316, P=0.005 and MR-proADM (β=0.284, P<0.020 levels were associated with increased aortic stiffness independently of age, blood pressure, and renal function. NT-proBNP was the strongest predictor for high aortic stiffness (area under the curve: 0.82, 95% CI 0.67–0.96. Conclusion. At a chronic stage after STEMI, concentrations of biomarkers for hemodynamic stress, especially NT-proBNP, are positively correlated with aortic stiffness. These biomarkers might also be useful as predictors of high aortic stiffness after STEMI.

  5. Viscoelastic Properties of the Aortic Valve Interstitial Cell

    OpenAIRE

    Merryman, W. David; Bieniek, Paul D.; Guilak, Farshid; Michael S Sacks

    2009-01-01

    There has been growing interest in the mechanobiological function of the aortic valve interstitial cell (AVIC), due to its role in valve tissue homeostasis and remodeling. In a recent study we determined the relation between diastolic loading of the AV leaflet and the resulting AVIC deformation, which was found to be substantial. However, due to the rapid loading time of the AV leaflets during closure (~0.05 s), time-dependent effects may play a role in AVIC deformation during physiological f...

  6. Novel pharmacological strategies to prevent aortic complications in Marfan syndrome

    OpenAIRE

    Matt, Peter; Eckstein, Friedrich

    2011-01-01

    The Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the FBN1 gene. Recent molecular studies, most performed in mouse models, revealed that the MFS is more a developmental abnormality with broad and complex effects on the morphogenesis and function of multiple organ systems. FBN1 haploinsufficiency and dysregulated transforming growth factor-beta (TGF-β) signaling seem to be critical for clinical manifestations in MFS including aortic root dilatation. Aort...

  7. HAS-1 genetic polymorphism in sporadic abdominal aortic aneurysm

    OpenAIRE

    Alberto Balbarini; Rossella Di Stefano; Marco Nuti; Stefano Landi; Chiara Armani

    2009-01-01

    The hyaluronan synthase 1 (HAS-1) gene encodes a plasma membrane protein that synthesizes hyaluronan (HA), an extracellular matrix molecule. Accumulating evidence emphasizes the relevance of HA metabolism in an increasing number of processes of clinical interest, including abdominal aortic aneurysm (AAA). The existence of aberrant splicing variants of the HAS-1 gene could partly explain the altered extracellular matrix architecture and influence various biological functions, resulting in prog...

  8. Rapid donor liver procurement with only aortic perfusion

    Institute of Scientific and Technical Information of China (English)

    Qi-Yuan Lin; KK Chui; AR-Nitin Rao

    2001-01-01

    ATM: to describe a rapid technique for procurement of donor liver with aortic perfusion only (APO). METHODS: Only the aorta is cannulated and perfused with chilled preservation solution. RESULTS: The quality of donor liver can ensure the grafted liver functions. CONCLUSION: The method of APO can simplify the operative procedure, compared with the dual cannulation. It also can minimize the danger of injuring vascular structures and involve less dissection.

  9. Talking Speech Input.

    Science.gov (United States)

    Berliss-Vincent, Jane; Whitford, Gigi

    2002-01-01

    This article presents both the factors involved in successful speech input use and the potential barriers that may suggest that other access technologies could be more appropriate for a given individual. Speech input options that are available are reviewed and strategies for optimizing use of speech recognition technology are discussed. (Contains…

  10. The role of transesophageal echocardiography in aortic surgery.

    Science.gov (United States)

    Nowak-Machen, Martina

    2016-09-01

    Aortic disease, when left untreated, is still associated with major morbidity and mortality. Aortic dissection and aortic aneurysm are the main reasons for performing aortic surgery procedures in the adult. Imaging techniques such as computed tomography and magnetic resonance imaging play a key role in the preoperative evaluation. Transesophageal echocardiography (TEE) has become a safe and invaluable perioperative imaging tool for aortic disease over the past decade with high sensitivity and specificity. TEE can increase patient safety and improve overall patient outcome in aortic surgery. Especially during endovascular aortic repair, TEE is more sensitive than other imaging modalities in diagnosing complications such as graft endoleaks. Newer echocardiographic techniques such as three-dimensional (3D) TEE and contrast-enhanced TEE are emerging and seem to have a valuable role especially in aortic dissection repair and endovascular aortic stent procedures. In the absence of contraindications, TEE should generally be performed during aortic surgery and endovascular aortic procedures. PMID:27650342

  11. Pregnancy after aortic root replacement in Loeys-Dietz syndrome: High risk of aortic dissection.

    Science.gov (United States)

    Braverman, Alan C; Moon, Marc R; Geraghty, Patrick; Willing, Marcia; Bach, Christopher; Kouchoukos, Nicholas T

    2016-08-01

    Loeys-Dietz syndrome due to mutations in TGFBR1 and 2 is associated with early and aggressive aortic aneurysm and branch vessel disease. There are reports of uncomplicated pregnancy in this condition, but there is an increased risk of aortic dissection and uterine rupture. Women with underlying aortic root aneurysm are cautioned about the risk of pregnancy-related aortic dissection. Prophylactic aortic root replacement is recommended in women with aortopathy and aortic root dilatation to lessen the risk of pregnancy. There is limited information in the literature about the outcomes of pregnancy after root replacement in Loeys-Dietz syndrome. We present a case series of three women with Loeys-Dietz syndrome who underwent elective aortic root replacement for aneurysm disease and subsequently became pregnant and underwent Cesarean section delivery. Each of these women were treated with beta blockers throughout pregnancy. Surveillance echocardiograms and noncontrast MRA studies during pregnancy remained stable demonstrating no evidence for aortic enlargement. Despite the normal aortic imaging and careful observation, two of the three women suffered acute aortic dissection in the postpartum period. These cases highlight the high risk of pregnancy following aortic root replacement in Loeys-Dietz syndrome. Women with this disorder are recommended to be counseled accordingly. © 2016 Wiley Periodicals, Inc. PMID:27125181

  12. Regional aortic distensibility and its relationship with age and aortic stenosis: a computed tomography study.

    Science.gov (United States)

    Wong, Dennis T L; Narayan, Om; Leong, Darryl P; Bertaso, Angela G; Maia, Murilo G; Ko, Brian S H; Baillie, Timothy; Seneviratne, Sujith K; Worthley, Matthew I; Meredith, Ian T; Cameron, James D

    2015-06-01

    Aortic distensibility (AD) decreases with age and increased aortic stiffness is independently associated with adverse cardiovascular outcomes. The association of severe aortic stenosis (AS) with AD in different aortic regions has not been evaluated. Elderly subjects with severe AS and a cohort of patients without AS of similar age were studied. Proximal aortic cross-sectional-area changes during the cardiac cycle were determined using retrospective-ECG-gating on 128-detector row computed-tomography. Using oscillometric-brachial-blood-pressure measurements, the AD at the ascending-aorta (AA), proximal-descending-aorta (PDA) and distal-descending-aorta (DDA) was determined. Linear mixed effects modelling was used to determine the association of age and aortic stenosis on regional AD. 102 patients were evaluated: 36 AS patients (70-85 years), 24 AS patients (>85 years) and 42 patients without AS (9 patients DDA (1.1 ± 1.2 vs. 1.2 ± 0.8, P = 0.97). In patients without AS, AD decreased with age in all aortic regions (P < 0.001). The AA in patients <50 years were the most distensible compared to other aortic regions. There is regional variation in aortic distensibility with aging. Patients with aortic stenosis demonstrated regional differences in aortic distensibility with lower distensibility demonstrated in the proximal ascending aorta compared to an age-matched cohort. PMID:25855464

  13. Case report of severe Cushing’s syndrome in medullary thyroid cancer complicated by functional diabetes insipidus, aortic dissection, jejunal intussusception, and paraneoplastic dysautonomia: remission with sorafenib without reduction in cortisol concentration

    OpenAIRE

    Hammami, Muhammad M.; Duaiji, Najla; Mutairi, Ghazi; Aklabi, Sabah; Qattan, Nasser; Abouzied, Mohei El-Din M.; Sous, Mohamed W.

    2015-01-01

    Background Normalization of cortisol concentration by multikinase inhibitors have been reported in three patients with medullary thyroid cancer-related Cushing’s syndrome. Aortic dissection has been reported in three patients with Cushing’s syndrome. Diabetes insipidus without intrasellar metastasis, intestinal intussusception, and paraneoplastic dysautonomia have not been reported in medullary thyroid cancer. Case presentation An adult male with metastatic medullary thyroid cancer presented ...

  14. Submillisecond precision of the input-output transformation function mediated by fast sodium dendritic spikes in basal dendrites of CA1 pyramidal neurons.

    Science.gov (United States)

    Ariav, Gal; Polsky, Alon; Schiller, Jackie

    2003-08-27

    The ability of cortical neurons to perform temporally accurate computations has been shown to be important for encoding of information in the cortex; however, cortical neurons are expected to be imprecise temporal encoders because of the stochastic nature of synaptic transmission and ion channel gating, dendritic filtering, and background synaptic noise. Here we show for the first time that fast local spikes in basal dendrites can serve to improve the temporal precision of neuronal output. Integration of coactivated, spatially distributed synaptic inputs produces temporally imprecise output action potentials within a time window of several milliseconds. In contrast, integration of closely spaced basal inputs initiates local dendritic spikes that amplify and sharpen the summed somatic potential. In turn, these fast basal spikes allow precise timing of output action potentials with submillisecond temporal jitter over a wide range of activation intensities and background synaptic noise. Our findings indicate that fast spikes initiated in individual basal dendrites can serve as precise "timers" of output action potentials in various network activity states and thus may contribute to temporal coding in the cortex.

  15. Graft infections after surgical aortic reconstructions

    NARCIS (Netherlands)

    Berger, P.

    2015-01-01

    Prosthetic vascular grafts are frequently used to reconstruct (part) of the aorta. Every surgical procedure caries a certain risk for infection and when a prosthetic aortic graft is implanted, this may lead to an aortic graft infection (AGI). Endovascular techniques have gradually replaced open surg

  16. Thoraco-abdominal aortic aneurysm branched repair

    NARCIS (Netherlands)

    Verhoeven, E. L. G.; Tielliu, I. F. J.; Ferreira, M.; Zipfel, B.; Adam, D. J.

    2010-01-01

    Open thoraco-abdominal aortic aneurysm repair is a demanding procedure with high impact on the patient and the operating team. Results from expert centres show mortality rates between 3-21%, with extensive morbidity including renal failure and paraplegia. Endovascular repair of abdominal aortic aneu

  17. Magnetic Resonance Imaging of Thoracic Aortic Dissections

    OpenAIRE

    Sax, Steven L.

    1990-01-01

    Magnetic resonance imaging is an excellent noninvasive method for evaluating thoracic aortic dissections. A variety of magnetic resonance scans of aortic dissections are shown, documenting the ability of magnetic resonance to image the true lumen, the false channel, and the intimal septum. Detail is provided on magnetic resonance imaging techniques and findings. (Texas Heart Institute Journal 1990;17:262-70)

  18. Transcatheter Aortic Valve Replacement in Europe

    DEFF Research Database (Denmark)

    Mylotte, Darren; Osnabrugge, Ruben L J; Windecker, Stephan;

    2013-01-01

    The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy.......The authors sought to examine the adoption of transcatheter aortic valve replacement (TAVR) in Western Europe and investigate factors that may influence the heterogeneous use of this therapy....

  19. Global Strain in Severe Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Videbæk, Lars; Poulsen, Mikael K;

    2012-01-01

    BACKGROUND: -Global longitudinal systolic strain (GLS) is often reduced in aortic stenosis despite normal ejection fraction. The importance of reduced preoperative GLS on long-term outcome after aortic valve replacement (AVR) is unknown. METHODS AND RESULTS: -A total of 125 patients with severe...

  20. Changes of ultrastructure and function of the aortic endothelium in streptozotocin-diabetic rats and effect of perindopril%糖尿病大鼠主动脉内皮形态功能及培哚普利影响的研究

    Institute of Scientific and Technical Information of China (English)

    周敏; 钟惠菊; 吴晓英; 刘世坤; 张冬梅

    2001-01-01

    探讨链脲菌素(STZ)糖尿病(DM)大鼠血管内皮超微结构和功能变化,以及培哚普利对其影响。雄性SD大鼠随机分为正常对照组(NC)、DM对照组(DC)、DM治疗组(DP),病程4周后DP组每天予培哚普利2mg.kg-1。分别于第4,8,16周测血糖、血浆ET-1和AngⅡ,并取主动脉作电镜观察。结果显示:DC组8周时,内皮细胞线粒体明显肿胀、空泡变,16周时血管内膜增厚,内皮细胞广泛坏死脱落,但DP组病变明显减轻。各病程中DC组血浆AngⅡ均明显升高,血浆ET-1在8周时明显升高,而16周时明显降低,在DP组血浆AngⅡ明显降低,ET-1则先降(8周)后升(16周)。提示糖尿病大鼠主动脉内皮细胞随病程不同出现超微结构和功能变化,血浆ET-1可能是反应内皮细胞损伤的一个指标,培哚普利对糖尿病大鼠主动脉内皮细胞损伤有一定保护作用。%To investigate the alteration of ultrastructure and function ofthe aortic endothelium in streptozotocin (STZ)-diabetic rats and the effect of perindopril, male SD rats were randomly divided into normal group (NC), diabetes control group (DC), diabetes group treated with perindopril (2mg.kg-1.d-1) which was administered after 4 weeks. At 4,8,16 weeks after injecting STZ, glucose, plasma endothelin-1 and angiotensin Ⅱ were respectively measured, and we also observed aortic endothelial cell under the electron microscope. Results: In DC group, there were mitochondrial edema and vacuolization obviously in aortic endothelial cells at 8 weeks, and extensive endothelial cell necrosis and exfoliation were observed at 16 weeks, while pathological changes in the DP group were abated significantly. Plasma Ang Ⅱ levels were increased significantly at different times in DC group, and plasma ET-1 levels were obviously increased at 8weeks and greatly decreased at 16 weeks. In DP groups, plasma Ang Ⅱ levels obviously decreased, ET-1 levels declined at 8 weeks

  1. ColloInputGenerator

    DEFF Research Database (Denmark)

    2013-01-01

    it as input for basic collexeme collostructional analysis (Stefanowitsch & Gries 2003) in Gries' (2007) program. ColloInputGenerator is, in its current state, based on programming commands introduced in Gries (2009). Projected updates: Generation of complete work-ready frequency lists.......This is a very simple program to help you put together input files for use in Gries' (2007) R-based collostruction analysis program. It basically puts together a text file with a frequency list of lexemes in the construction and inserts a column where you can add the corpus frequencies. It requires...

  2. Acute aortic dissection in pregnant women.

    Science.gov (United States)

    Yang, Zhaohua; Yang, Shouguo; Wang, Fangshun; Wang, Chunsheng

    2016-05-01

    Acute aortic dissection occurring during pregnancy represents a lethal risk to both the mother and fetus. Management of parturient with acute aortic dissection is complex. We report our experience of two pregnancies with type A acute aortic dissection. One patient is a 31-year-old pregnant woman (33rd gestational week) with a bicuspid aortic valve and the other is a 32-year-old pregnant woman (30th gestational week) with the Marfan syndrome. In both cases, a combined emergency operation consisting of Cesarean section, total hysterectomy prior to corrective surgery for aortic dissection was successfully performed within a relatively short period of time after the onset. Both patients' postoperative recovery was uneventful, and we achieved a favorable maternal and fetal outcome. PMID:25085319

  3. Intraoperative tracking of aortic valve plane

    Science.gov (United States)

    Nguyen, Duc Long Hung; Garreau, Mireille; Auffret, Vincent; Le Breton, Hervé; Verhoye, Jean-Philippe; Haigron, Pascal

    2013-01-01

    The main objective of this work is to track the aortic valve plane in intra-operative fluoroscopic images in order to optimize and secure Transcatheter Aortic Valve Implantation (TAVI) procedure. This paper is focused on the issue of aortic valve calcifications tracking in fluoroscopic images. We propose a new method based on the Tracking-Learning-Detection approach, applied to the aortic valve calcifications in order to determine the position of the aortic valve plane in intra-operative TAVI images. This main contribution concerns the improvement of object detection by updating the recursive tracker in which all features are tracked jointly. The approach has been evaluated on four patient databases, providing an absolute mean displacement error less than 10 pixels ≈ 2mm). Its suitability for the TAVI procedure has been analyzed. PMID:24110703

  4. Stroke in Patients With Aortic Stenosis

    DEFF Research Database (Denmark)

    Greve, Anders Møller; Dalsgaard, Morten; Bang, Casper N;

    2014-01-01

    , and poststroke survival a secondary outcome. Cox models treating AVR as a time-varying covariate were adjusted for atrial fibrillation and congestive heart failure, hypertension, age≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years and female sex (CHA2DS2-VASc......BACKGROUND AND PURPOSE: There are limited data on risk stratification of stroke in aortic stenosis. This study examined predictors of stroke in aortic stenosis, the prognostic implications of stroke, and how aortic valve replacement (AVR) with or without concomitant coronary artery bypass grafting...... influenced the predicted outcomes. METHODS: Patients with mild-to-moderate aortic stenosis enrolled in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. Diabetes mellitus, known atherosclerotic disease, and oral anticoagulation were exclusion criteria. Ischemic stroke was the primary end point...

  5. Transcatheter aortic valve replacement in elderly patients

    Institute of Scientific and Technical Information of China (English)

    Dimytri Siqueira; Alexandre Abizaid; Magaly Arrais J.; Eduardo Sousa

    2012-01-01

    Aortic stenosis is the most common native valve disease, affecting up to 5% of the elderly population. Surgical aortic valve replacement reduces symptoms and improves survival, and is the definitive therapy in patients with symptomatic severe aortic stenosis. However, despite the good results of classic surgery, risk is markedly increased in elderly patients with co-morbidities. Transcatheter aortic valve replacement (TAVR) allows implantation of a prosthetic heart valve within the diseased native aortic valve without the need for open heart surgery and cardiopulmonary bypass, offering a new therapeutic option to elderly patients considered at high surgical risk or with contraindications to surgery. To date, several multicenter registries and a randomized trial have confirmed the safety and efficacy of TAVR in those patients. In this chapter, we review the background and clinical applications of TAVR in elderly patients.

  6. Reoperation on aortic disease in patients with previous aortic valve surgery

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-gang; ZHANG Liang; YU Cun-tao; QIAN Xiang-yang; CHANG Qian

    2013-01-01

    Background Aortic valve replacement (AVR) is a safe and effective method in the treatment of aortic valve diseases.This study aimed to increase the understanding on re-treatment of aortic diseases after aortic valve surgery through a retrospective analysis of 47 related cases.Methods Forty-seven patients (38 males and 9 females) with previous aortic valve surgery have received reoperation on aorta from January 2003 to June 2012,and the mean interval time of re-intervention to aortic disease was 6 years ((6.0± 3.8) years).The secondary aortic surgery included aortic root replacement (14 cases),ascending aorta replacement (10 cases),aortic root/ascending aorta plus total arch replacement with stented elephant trunk implantation (21 cases),and total thoracoabdominal aorta replacement (2 cases).All these patients have received outpatient re-exams or follow-up by phone calls.Results After the initial aortic valve replacement,patients suffered from aortic dissection (25 cases,53%),ascending aortic aneurysm (12 cases,26%) or aortic root aneurysm (10 cases,21%).Diameter in ascending aorta increased (5.2±7.1) mm per year and aortic sinus (3.3±3.1) mm per year.The annual growth value of diameter in ascending aorta was higher in patients with rheumatic heart disease than that in Marfan syndrome (P<0.05).All 47 patients have received reoperation on aorta.One patient died in operating room because aortic dissection seriously involved right coronary artery.Seven patients had renal insufficiency after operation; neurological complications occurred in 14 patients including 7 patients with stroke and the others with transient brain dysfunction.All patients were followed up,the mean survival time was (97.25±17.63) months,95% confidence interval was 55.24-73.33 months.Eight cases were died during follow-up and five-year survival rate was 83%.Conclusion To reduce the aortic adverse events after first aortic valve surgery,it is necessary to actively treat and strictly

  7. Screening for Abdominal Aortic Aneurysm

    OpenAIRE

    Linné, Anneli

    2014-01-01

    Abdominal Aortic Aneurysm (AAA) is a common disease with a prevalence of 1.5-2.0% in 65-year old men in Sweden. The risk of having AAA is increased with smoking, high age, family history of AAA and cardiovascular disease. Women have a lower prevalence (0.5%) and develop AAA later in life. An AAA seldom gives any symptom prior to rupture. Untreated rupture is associated with 100% mortality, while surgically treated rupture is associated with 25-70% mortality. Prophylactic sur...

  8. Input chains and industrialization

    OpenAIRE

    Ciccone, Antonio

    2000-01-01

    A key aspect of industrialization is the adoption of increasing-returns-to-scale, industrial, technologies. Two other, well-documented aspects are that industrial technologies are adopted throughout intermediate-input chains and that they use intermediate inputs intensively relative to the technologies they replace. These features of industrial technologies combined imply that countries with access to similar technologies may have very different levels of industrial...

  9. Bicuspid Aortic Valve Disease and Ascending Aortic Aneurysms: Gaps in Knowledge

    Directory of Open Access Journals (Sweden)

    Katie L. Losenno

    2012-01-01

    Full Text Available The bicuspid aortic valve is the most common congenital cardiac anomaly in developed nations. The abnormal bicuspid morphology of the aortic valve results in valvular dysfunction and subsequent hemodynamic derangements. However, the clinical presentation of bicuspid aortic valve disease remains quite heterogeneous with patients presenting from infancy to late adulthood with variable degrees of valvular stenosis and insufficiency and associated abnormalities including aortic coarctation, hypoplastic left heart structures, and ascending aortic dilatation. Emerging evidence suggests that the heterogeneous presentation of bicuspid aortic valve phenotypes may be a more complex matter related to congenital, genetic, and/or connective tissue abnormalities. Optimal management of patients with BAV disease and associated ascending aortic aneurysms often requires a thoughtful approach, carefully assessing various risk factors of the aortic valve and the aorta and discerning individual indications for ongoing surveillance, medical management, and operative intervention. We review current concepts of anatomic classification, pathophysiology, natural history, and clinical management of bicuspid aortic valve disease with associated ascending aortic aneurysms.

  10. Aortic root size and prevalence of aortic regurgitation in elite strength trained athletes.

    Science.gov (United States)

    Babaee Bigi, Mohammad Ali; Aslani, Amir

    2007-08-01

    Athletes involved in mainly static or isometric exercise (e.g., weight lifting, power lifting, and bodybuilding) develop pressure overloads due to the high systemic arterial pressure found in this type of exercise. It is hypothesized that chronically elevated aortic wall tension in strength-trained athletes is associated with aortic dilatation and regurgitation. The aim of this study was to evaluate aortic root size and the prevalence of aortic regurgitation in elite strength-trained athletes. The cohort included 100 male athletes (mean age 22.1 +/- 3.6 years; all were finalists or medalists in the country) and 128 healthy age- and height-matched subjects (the control group). Aortic root diameters at end-diastole were measured at 4 locations: (1) the aortic annulus, (2) the sinuses of Valsalva, (3) the sinotubular junction, and (4) the maximal diameter of the proximal ascending aorta. Aortic root diameters at all levels were significantly greater in the strength-trained athletes (p 18 and 36 and 54 months), progressive enlargement was found at all aortic diameters. In conclusion, aortic root diameters in all segments of the aortic root were significantly greater in elite strength-trained athletes compared with an age- and height-matched population.

  11. Giant Thoracic Aneurysm Following Valve Replacement for Bicuspid Aortic Valve.

    Science.gov (United States)

    Tran, Cao; Ul Haq, Ehtesham; Nguyen, Ngoc; Omar, Bassam

    2015-01-01

    Bicuspid aortic valve is a common congenital anomaly associated with aortopathy, which can cause aortic root dilatation, necessitating regular screening if the aortic root is > 4.0 cm. Despite the low absolute incidence of aortic complications associated with bicuspid aortic valve in the general population, the consequences of such complications for an individual patient can be devastating. Herein we propose a balanced algorithm that incorporates recommendations from the three major guidelines for follow-up imaging of the aortic root and ascending thoracic aorta in patients with a bicuspid aortic valve, maintaining the current recommendations with regard to surgical thresholds. PMID:26827748

  12. Recovery from anemia in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation--prevalence, predictors and clinical outcome

    DEFF Research Database (Denmark)

    De Backer, Ole; Arnous, Samer; Lønborg, Jacob;

    2014-01-01

    -recovery, while blood transfusion (OR 0.31, P = 0.038) and chronic kidney disease (CKD, OR 0.33, P = 0.043) were identified as negative predictors at, respectively, one and two years after TAVI. When compared to patients without baseline anemia, those anemic patients with Hb-recovery had a similar functional......INTRODUCTION: Preoperative anemia is common in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) and has been linked to a poorer outcome--including a higher 1-year mortality. The aim of this study was to investigate the impact of successful TAVI...... on baseline anemia. METHODS: A total of 253 patients who survived at least 1 year following TAVI were included in this study. The prevalence, predictors and clinical outcome of hemoglobin (Hb)-recovery were assessed. RESULTS: The prevalence of baseline anemia was 49% (n = 124)--recovery from anemia occurred...

  13. Regge-like initial input and evolution of non-singlet structure functions from DGLAP equation up to next-next-to-leading order at low and low 2

    Indian Academy of Sciences (India)

    Nayan Mani Nath; Mrinal Kumar Das; Jayanta Kumar Sarma

    2015-10-01

    This is an attempt to study how the features of Regge theory, along with QCD predictions, lead towards the understanding of unpolarized non-singlet structure functions $F_{2}^{\\text{NS}}$ (, 2) and 3 (, 2) at low and low 2 . Combining the features of perturbative quantum chromodynamics (pQCD) and Regge theory, an ansatz for $F_{2}^{\\text{NS}}$ (, 2) and 3 (, 2) structure functions at small was obtained, which when used as the initial input to Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) equation, gives the 2 evolution of the non-singlet structure functions. The non-singlet structure functions, evolved in accordance with DGLAP evolution equations up to next-next-to-leading order are studied phenomenologically in comparison with the available experimental and parametrization results taken from NMC, CCFR, NuTeV, CORUS, CDHSW, NNPDF and MSTW Collaborations and a very good agreement is observed in this regard.

  14. Quadricuspid aortic valve with ruptured sinus of Valsalva.

    Science.gov (United States)

    Akerem Khan, Shamruz Khan; Tamin, Syahidah Syed; Burkhart, Harold M; Araoz, Philip A; Young, Phillip M

    2013-02-01

    We present a case of a 24-year-old woman who was diagnosed with quadricuspid aortic valve with ruptured sinus of Valsalva. Quadricuspid aortic valve is a rare congenital cardiac anomaly. The recognition of quadricuspid aortic valve has clinical significance as it causes aortic valve dysfunction, and is often associated with other congenital cardiac abnormalities. We showed the important role of multimodality imaging in diagnosing a quadricuspid aortic valve associated with ruptured sinus of Valsalva. PMID:22874066

  15. Tissue Velocities and Myocardial Deformation in Asymptomatic and Symptomatic Aortic Stenosis

    DEFF Research Database (Denmark)

    Carstensen, Helle Gervig; Larsen, Linnea Hornbech; Hassager, Christian;

    2015-01-01

    BACKGROUND: Assessment of myocardial longitudinal function has proved to be a sensitive marker of deteriorating myocardial function in aortic stenosis, demonstrated by both color Doppler tissue imaging and recently by two-dimensional speckle-tracking echocardiography. The aim of this study...... was to compare velocity (color Doppler tissue imaging) and deformation (two-dimensional speckle-tracking echocardiography) in relation to global and regional longitudinal function in asymptomatic and severe symptomatic aortic stenosis. METHODS: In a cross-sectional design, 231 patients with aortic stenosis were...... = 59). RESULTS: Among all global (peak systolic s', diastolic e' and a', longitudinal displacement, and global longitudinal strain and strain rate) and regional longitudinal (basal, middle, and apical longitudinal strain and strain rate) parameters, only diastolic e', longitudinal displacement...

  16. Input inefficiency in commercial banks: a normalized quadratic input distance approach

    OpenAIRE

    Thomas L. Marsh; Featherstone, Allen M.; Garrett, Thomas A.

    2003-01-01

    A normalized quadratic input distance function is proposed with which to estimate technical efficiency on commercial banks regulated by the Federal Reserve System. The study period covers 1990 to 2000 using individual bank information from the Call and Banking Holding Company Database. A stochastic frontier model is specified to estimate the input normalized distance function and obtain measures of technical efficiency.

  17. Results of surgery for aortic regurgitation due to aortic valve prolapse.

    Directory of Open Access Journals (Sweden)

    Shigenobu,Masaharu

    1988-12-01

    Full Text Available The clinical, hemodynamic and pathological findings of 13 patients with aortic regurgitation due to aortic valve prolapse caused by advanced myxomatous degeneration were evaluated. Eleven patients showed a favorable outcome with no complications resulting from surgery. One patient died from aortic dissection, and another died suddenly from an unknown cause. Five patients had mitral valve prolapse as a complication. Ten patients (77% had a long-standing history of hypertension. Twelve patients (92% were male. None of the patients had the stigmata of Marfan's syndrome. All patients had marked myxomatous degeneration of the aortic valves without any inflammatory changes. Two patients showed microcalcification; 7 demonstrated moderate fibrosis. Five patients showed severe fragility of the cusps which appeared redundant, gelatinous and softened by degenerative changes. Myxomatous degeneration of the aortic valve is not rare, and, in fact, it may be one of the most common pathologic and clinical entities associated with pure aortic insufficiency.

  18. Hybrid treatment of recurring thoracoabdominal aortic aneurysm concomitant with retrograde type A aortic dissection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Min-hong; GUO Wei; DU Xin; XIONG Jiang

    2010-01-01

    So far, standard therapy of complex thoracoabdominal aortic disease is open surgical repair requiring aortic clamping and replacement of the involved segment.Despite significant improvements, morbidity and mortality of open surgery remain high.I As a result, open surgery is often withheld owing to severe comorbidities of the patients. Endovascular technique has emerged as an alternative for treatment of these diseases in high risk patients,2 and has enlarged the options of treatment of complex aortic diseases. However, an endovascular approach alone is often deemed unsuitable for some complex aortic disorders because of the close proximity of the supraaortic or visceral branches. A hybrid open-endovascular approach has therefore been proposed as a viable alternative. We present here a unique patient with recurring thoracoabdominal aortic aneurysm (TAAA) concomitant with an aortic dissection (AD) treated by a hybrid open-endovascular approach.

  19. Valvular Aortic Stenosis: A Proteomic Insight

    Directory of Open Access Journals (Sweden)

    Fernando Vivanco

    2010-02-01

    Full Text Available Calcified aortic valve disease is a slowly progressive disorder that ranges from mild valve thickening with no obstruction of blood flow, known as aortic sclerosis, to severe calcification with impaired leaflet motion or aortic stenosis. In the present work we describe a rapid, reproducible and effective method to carry out proteomic analysis of stenotic human valves by conventional 2-DE and 2D-DIGE, minimizing the interference due to high calcium concentrations. Furthermore, the protocol permits the aortic stenosis proteome to be analysed, advancing our knowledge in this area. Summary: Until recently, aortic stenosis (AS was considered a passive process secondary to calcium deposition in the aortic valves. However, it has recently been highlighted that the risk factors associated with the development of calcified AS in the elderly are similar to those of coronary artery disease. Furthermore, degenerative AS shares histological characteristics with atherosclerotic plaques, leading to the suggestion that calcified aortic valve disease is a chronic inflammatory process similar to atherosclerosis. Nevertheless, certain data does not fit with this theory making it necessary to further study this pathology. The aim of this study is to develop an effective protein extraction protocol for aortic stenosis valves such that proteomic analyses can be performed on these structures. In the present work we have defined a rapid, reproducible and effective method to extract proteins and that is compatible with 2-DE, 2D-DIGE and MS techniques. Defining the protein profile of this tissue is an important and challenging task that will help to understand the mechanisms of physiological/pathological processes in aortic stenosis valves.

  20. An abdominal aortic calcification as a RISK FACTOR FOR cardio -cerebral events in patients with peripheral arterial

    Directory of Open Access Journals (Sweden)

    V. A. Zelinskiy

    2012-01-01

    Full Text Available Background. The patients with abdominal aortic calcification have a high risk of cardiocerebral events, but the pathways of them have not been reported so far. The goal of our study was to assess the structure and function of myocardium and to determine the morphological features of carotid artery atherosclerosis in patients with abdominal aortic calcification.Materials and methods. A total of 167 executive patients with peripheral arterial disease were enrolled in study. The study group included 85 patients with abdominal aortic calcification (men – 95.3 %; age median was – 66.6 ± 12. Control group included 82 patients without objective signs of abdominal aortic calcification. Abdominal aortic calcification was detected by CT imaging. All patients have undergone echocardiography and duplex scanning of carotid arteries.Results. Prevalence and severity of ischemic heart disease and cerebrovascular disease were statistically significant higher in patients with abdominal aortic calcification (91.7, 65.8 % vs. 67, 37.3 % (р < 0.01. We have found statistically significant differences between groupsin heart structure and function. A high left ventricular wall thickness (р < 0.01, left atrium dilation (р < 0.01 and enhanced of left ventricular mass (р < 0.05, ejection fraction reduction (р < 0.05 and more common diastolic dysfunction (р < 0.05 were determined inpatients with abdominal aortic calcification. An intima-media thickness of the common carotid artery was significantly higher in study group patients (1.38 ± 0.07 mm vs. 1.14 ± 0.06 mm (р < 0.001.Conclusion. Our findings suggested that abdominal aortic calcification is main reason of hypertrophy and dilation in the left heart due to enhanced peripheral resistance. Hypertrophy and dilation in the left heart is provided a high risk of cardiovascular events in patients withabdominal aortic calcification.

  1. Anatomics Knowledges of Aortic Root in the Transcatheter Aortic Valve Implantation.

    OpenAIRE

    Marcelo Cerezo; Omar Bertani; Gisela Panciroli; Sebastián Duhalde; Karina Ferreira; Luciano Honaine

    2010-01-01

    The Aortic Valve is a valvular system that bears different high pressure forces. It takes part of a complex structure called Aortic Root. Nowadays, anatomic knowledge has taken a preponderant role, due to the use of the Transcatether Aortic Valve Implant (TAVI). To describe the patient´s characteristics which exclude them of the TAVI for anatomic reasons in cadaveric dissections and transthoracic echocardiograms. A descriptive retrospective analysis of 67 individuals was performed and divided...

  2. Open surgical repair of abdominal aortic aneurysm: Proximal aortic control by endoaortic balloon - A novel approach

    OpenAIRE

    Balakrishnan Soundaravalli; Palaniappan, M.; Rajani Sundar; Chandrasekar, P.

    2012-01-01

    Patients with infrarenal abdominal aortic aneurysm with unfavorable anatomy for endovascular aneurysm repair have to undergo open surgical repair. Open surgery has its own morbidity in terms of proximal clamping and declamping, bleeding and prolonged hospital stay and mortality. We present two such patients with juxtarenal abdominal aortic aneurysm who underwent open surgical repair. The proximal aortic control during open surgical repair of the aneurysm was achieved by endoaortic balloon occ...

  3. Open surgical repair of abdominal aortic aneurysm: Proximal aortic control by endoaortic balloon - A novel approach

    Directory of Open Access Journals (Sweden)

    Balakrishnan Soundaravalli

    2012-01-01

    Full Text Available Patients with infrarenal abdominal aortic aneurysm with unfavorable anatomy for endovascular aneurysm repair have to undergo open surgical repair. Open surgery has its own morbidity in terms of proximal clamping and declamping, bleeding and prolonged hospital stay and mortality. We present two such patients with juxtarenal abdominal aortic aneurysm who underwent open surgical repair. The proximal aortic control during open surgical repair of the aneurysm was achieved by endoaortic balloon occlusion technique.

  4. Bioreactor performance and functional gene analysis of microbial community in a limited-oxygen fed bioreactor for co-reduction of sulfate and nitrate with high organic input.

    Science.gov (United States)

    Xu, Xi-jun; Chen, Chuan; Wang, Ai-jie; Yu, Hao; Zhou, Xu; Guo, Hong-liang; Yuan, Ye; Lee, Duu-jong; Zhou, Jizhong; Ren, Nan-qi

    2014-08-15

    Limited-oxygen mediated synergistic relationships between sulfate-reducing bacteria (SRB), nitrate-reducing bacteria (NRB) and sulfide-oxidizing bacteria (SOB, including nitrate-reducing, sulfide-oxidizing bacteria NR-SOB) were predicted to simultaneously remove contaminants of nitrate, sulfate and high COD, and eliminate sulfide generation. A lab-scale experiment was conducted to examine the impact of limited oxygen on these oxy-anions degradation, sulfide oxidation and associated microbial functional responses. In all scenarios tested, the reduction of both nitrate and sulfate was almost complete. When limited-oxygen was fed into bioreactors, S(0) formation was significantly improved up to ∼ 70%. GeoChip 4.0, a functional gene microarray, was used to determine the microbial gene diversity and functional potential for nitrate and sulfate reduction, and sulfide oxidation. The diversity of the microbial community in bioreactors was increased with the feeding of limited oxygen. Whereas the intensities of the functional genes involved in sulfate reduction did not show a significant difference, the abundance of the detected denitrification genes decreased in limited oxygen samples. More importantly, sulfide-oxidizing bacteria may alter their populations/genes in response to limited oxygen potentially to function more effectively in sulfide oxidation, especially to elemental sulfur. The genes fccA/fccB from nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB), such as Paracoccus denitrificans, Thiobacillus denitrificans, Beggiatoa sp., Thiomicrospira sp., and Thioalkalivibrio sp., were more abundant under limited-oxygen condition. PMID:24981676

  5. [Minimally invasive cardiac surgery for aortic valve disease].

    Science.gov (United States)

    Fujimura, Y; Katoh, T; Hamano, K; Gohra, H; Tsuboi, H; Esato, K

    1998-12-01

    Recent surgical advances leading to good operative results have contributed to the trend to useminimally invasive approaches, even in cardiac surgery. Smaller incisions are clearly more cosmetically acceptable to patients. When using a minimally invasive approach, it is most important to maintain surgical quality without jeopardizing patients. A good operative visual field leads to good surgical results. In the parasternal approach, we use a retractor to harvest an internal thoracic artery in coronary artery bypass surgery. Retracting the sternum upward allows for a good surgical view and permits the use of an arch cannula rather than femoral cannulation. When reoperating for aortic valve repair, the j-sternotomy approach requires less adhesiolysis compared with the traditional full sternotomy. No special technique is necessary to perform aortic valve surgery using the j-sternotomy approach. However, meticulous attention must be paid to avoiding left ventricular air embolisms to prevent postoperative stroke or neurocognitive deficits, especially when utilizing a minimally invasive approach. Transesophageal echo is useful not only for monitoring cardiac function but also for monitoring the persence of air in the left ventricle and atrium. This paper compare as the degree of invasion of minimally invasive cardiac surgery and the traditional full sternotomy. No differences were found in the occurrence of systemic inflammatory response syndrome between patients undergoing minimally invasive cardiac surgery and the traditional technique. Therefore it is concluded that minimally invasive surgery for patients with aortic valve disease may become the standard approach in the near future.

  6. Management of Traumatic Aortic and Splenic Rupture in a Patient With Ascending Aortic Aneurysm.

    Science.gov (United States)

    Topcu, Ahmet Can; Ciloglu, Ufuk; Bolukcu, Ahmet; Dagsali, Sabri

    2016-08-01

    Traumatic aortic rupture is rupture of all or part of the aortic wall, mostly resulting from blunt trauma to the chest. The most common site of rupture is the aortic isthmus. Traumatic rupture of the ascending aorta is rare. A 62-year-old man with a family history of ascending aortic aneurysm was referred to our hospital after a motor vehicle accident. He had symptoms of cardiogenic shock. A contrast-enhanced computed tomographic scan revealed rupture of the proximal ascending aorta and an ascending aortic aneurysm with a diameter of 55 mm at the level of the sinuses of Valsalva. Transthoracic echocardiography at the bedside revealed severe aortic valvular insufficiency. We performed a successful Bentall procedure. During postoperative recovery, the patient experienced a cerebrovascular accident. Transesophageal echocardiography did not reveal thrombosis of the mechanical prosthesis. The patient's symptoms resolved in time, and he was discharged from the hospital on postoperative day 47 without any sequelae. He has been symptom free during a 6-month follow-up period. We suggest that individuals who have experienced blunt trauma to the chest and have symptoms of traumatic aortic rupture and a known medical history of ascending aortic aneurysm should be evaluated for a rupture at the ascending aorta and the aortic isthmus. PMID:27449463

  7. Combined surgical and catheter-based treatment of extensive thoracic aortic aneurysm and aortic valve stenosis

    DEFF Research Database (Denmark)

    De Backer, Ole; Lönn, Lars; Søndergaard, Lars

    2015-01-01

    endovascular aneurysm repair (TEVAR) has changed and extended management options in thoracic aorta disease, including in those patients deemed unfit or unsuitable for open surgery. Accordingly, transcatheter aortic valve replacement (TAVR) is increasingly used to treat patients with symptomatic severe aortic......An extensive thoracic aortic aneurysm (TAA) is a potentially life-threatening condition and remains a technical challenge to surgeons. Over the past decade, repair of aortic arch aneurysms has been accomplished using both hybrid (open and endovascular) and totally endovascular techniques. Thoracic...

  8. Medical image of the week: aortic ring

    Directory of Open Access Journals (Sweden)

    Wong C

    2014-10-01

    Full Text Available No abstract available. Article truncated after 150 words. A 78 year old man presented with altered mental status and was found to have an intraventricular hemorrhage. He was intubated for airway protection. On the post-intubation chest radiograph (Figure 1, the patient was noted to have a widening of the right paratracheal stripe. A CT chest (Figure 2 was obtained to characterize this finding and revealed an aortic ring which encircles the trachea and esophagus. Vascular rings are uncommon congenital abnormalities, accounting for approximately 1% of congenital heart disease. Complete vascular rings can occur with a right aortic arch with a ligamentum arteriosum or with a double aortic arch, such as with our patient (1. This ring can cause airway compression, stridor, esophageal compression, or no symptoms at all. As the embryo develops, the left fourth pharyngeal arch normally persists to become the aortic arch while the right fourth pharyngeal arch regresses. If both fourth pharyngeal arches persist, a ...

  9. Aortic aneurysm secondary to umbilical artery catheterization

    International Nuclear Information System (INIS)

    A 14-month-girl presented with an asymptomatic posterior mediastinal mass. She had a history of prematurity, umbilical artery catheterization, and sepsis. The diagnosis of aortic aneurysm was made by dynamic computed tomography. The aneurysm was successfully resected. (orig.)

  10. Type B Aortic Dissection: Management Updates

    Directory of Open Access Journals (Sweden)

    Naghmeh Moshtaghi

    2009-12-01

    Full Text Available Acute aortic dissection (AAD is the most frequent catastrophic event of the aorta; it occurs nearly three times as frequently as the rupture of abdominal aortic aneurysm. Sixty percent of dissection cases are classified as proximal or type A and 40% as distal or type B, according to the Stanford Classification. The most frequent causes of death in acute type B dissection are aortic rupture and malperfusion syndrome.We herein review recent data suggesting different management modalities of type B aortic dissection, including medical, surgical, and endovascular treatments. Although medical therapy is still the standard approach in uncomplicated cases, there are subgroups of patients who may benefit from endovascular management. Endovascular techniques or surgery are valuable options for complicated cases. Hybrid suites, multidisciplinary approaches, and good imaging techniques can be considered as the key to success in this regard.

  11. Valve selection in aortic valve endocarditis

    Science.gov (United States)

    Zubrytska, Yana

    2016-01-01

    Aortic prosthetic valve endocarditis (PVE) is a potentially life-threatening disease. Mortality and incidence of infective endocarditis have been reduced in the past 30 years. Medical treatment of aortic PVE may be successful in patients who have a prompt response after antibiotic treatment and who do not have prosthetic dysfunction. In advanced stages, antibiotic therapy alone is insufficient to control the disease, and surgical intervention is necessary. Surgical treatment may be lifesaving, but it is still associated with considerable morbidity and mortality. The aim of surgery is to perform a radical excision of all infected and necrotic tissue, reconstruction of the left ventricle outflow tract, and replacement of the aortic valve. There is no unanimous consensus on which is the optimal prosthesis to implant in this context, and several surgical techniques have been suggested. We aim to analyze the efficacy of the surgical treatment and discuss the issue of valve selection in patients with aortic valve endocarditis.

  12. Dissecting aortic aneurysm in maintenance hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Ounissi M

    2009-01-01

    Full Text Available The dissecting aortic aneurysm (DAA is a rare pathology that may result in fatal outcome. We report follow up of three cases of DAA patients undergoing maintenance hemo-dialysis who were managed conservatively.

  13. A rare cause of recurrent aortic dissection.

    Science.gov (United States)

    Agrawal, Yashwant; Gupta, Vishal

    2016-07-01

    We report the case of a 19-year-old man with a history of Loeys-Dietz syndrome (LDS), which was diagnosed when he had a Stanford type A aortic dissection. He also had multiple aneurysms including ones in the innominate, right common carotid, and right internal mammary arteries. He had had multiple procedures including Bentall's procedure, repeat sternotomy with complete arch and valve replacement, and coil embolization of internal mammary artery aneurysm in the past. His LDS was characterized by gene mutation for transforming growth factor-β receptor 1. He presented to our facility with sudden onset of back pain, radiating to the right shoulder and chest. He was diagnosed with Stanford type B aortic dissection and underwent thoracic aorta endovascular repair for his aortic dissection. This case represents the broad spectrum of pathology associated with LDS where even with regular surveillance and aggressive medical management the patient developed Stanford B aortic dissection. PMID:27358537

  14. Elective reconstruction of thoracoabdominal aortic aneurysm type IV by transabdominal approach

    Directory of Open Access Journals (Sweden)

    Marjanović Ivan

    2012-01-01

    Full Text Available Introduction. Thoracoabdominal aortic aneurysm (TAAA type IV represents an aortic dilatation from the level of the diaphragmatic hiatus to the iliac arteries branches, including visceral branches of the aorta. In the traditional procedure of TAAA type IV repair, the body is opened using thoractomy and laparotomy in order to provide adequate exposure of the descending thoracic and abdominal aorta for safe aortic reconstruction. Case report. We reported a 71-yearold man with elective reconstruction of the TAAA type IV performed by transabdominal approach. Computed tomography scans angiography revealed a TAAA type IV with diameter of 62 mm in the region of celiac trunk and superior mesenteric artery branching, and the largest diameter of 75 mm in the infrarenal aortic level. The patient comorbidity included a chronic obstructive pulmonary disease and hypertension, therefore he was treated for a prolonged period. In preparation for the planned aortic reconstruction asymptomatic carotid disease (occlusion of the left internal carotid artery and subtotal stenosis of the right internal carotid artery was diagnosed. Within the same intervention percutaneous transluminal angioplasty with stent placement in right internal carotid artery was made. In general, under endotracheal anesthesia and epidural analgesia, with transabdominal approach performed aortic reconstruction with tubular dakron graft 24 mm were, and reimplantation of visceral aortic branches into the graft performed. Postoperative course was uneventful, and the patient was discharged on the postoperative day 17. Control computed tomography scan angiography performed three months after the operation showed vascular state of the patient to be in order. Conclusion. Complete transabdominal approach to TAAA type IV represents an appropriate substitute for thoracoabdominal approach, without compromising safety of the patient. This approach is less traumatic, especially in patients with impaired

  15. Anesthetic management of transcatheter aortic valve implantation

    OpenAIRE

    Annalisa Franco; Chiara Gerli; Laura Ruggeri; Fabrizio Monaco

    2012-01-01

    Transcatheter aortic valve implantation (TAVI) is an emergent technique for high-risk patients with aortic stenosis. TAVI poses significant challenges about its management because of the procedure itself and the population who undergo the implantation. Two devices are currently available and marketed in Europe and several other technologies are being developed. The retrograde transfemoral approach is the most popular procedure; nevertheless, it may not be feasible in patients with significant ...

  16. Surveillance intervals for small abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Bown, Matthew J; Sweeting, Michael J; Brown, Louise C;

    2013-01-01

    Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture.......Small abdominal aortic aneurysms (AAAs [3.0 cm-5.4 cm in diameter]) are monitored by ultrasound surveillance. The intervals between surveillance scans should be chosen to detect an expanding aneurysm prior to rupture....

  17. Aortic dissection. Basic aspects and endovascular management

    International Nuclear Information System (INIS)

    Treatment of thoracic aortic pathology is complicated by the morbidity associated to the surgical procedure and to the frailty of an elderly and difficult population. Surgical operation in this kind of population frequently bears a significant incidence of death and long-term disability. In an effort to reduce the incidence of negative outcomes, minimally invasive techniques in the form of endovascular stenting have been introduced during the past decade. The technology, originally described by Parodi, and initially designed for its use in abdominal aortic aneurysms, has been adapted for the treatment of thoracic aortic aneurysms. Furthermore, an improved understanding of the pathophysiology and the natural history of thoracic aortic disease as well as the analysis of the outcomes have facilitated our treatment decisions in terms of the timing for an appropriate intervention. Treatment of thoracic aortic dissection using endovascular Stent is one of the more recent advances in this condition and is receiving increasing attention, as it is a less invasive alternative to an open surgical repair. Although this technology is still innovative, significant improvements have been made lately in the design and deployment of the endovascular Stent-grafts. These prostheses have been increasingly used to treat aneurysms, dissections and traumatic ruptures, as well as giant penetrating ulcers and intramural hematomas of the descending thoracic aorta with good early and mid-term outcomes. The rareness, complexity and severity of the pathology and the theoretically high risk of complications should render the surgeon extremely cautious especially with young patients. Conceptually, the endo luminal treatment in the acute phase seems to be the solution and will probably become a preferred therapy while technical refinement is under way. Worldwide experience is growing and with this a better understanding of the indications and limitations of this innovative therapy will be

  18. Effect of age on aortic atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    Michael A. Chen; Miwa Kawakubo; Patrick M. Colletti; Dongxiang Xu; Laurie LaBree Dustin; Robert Detrano; Stanley P Azen; Nathan D. Wong; Xue-Qiao Zhao

    2013-01-01

    Objective To examine the association of atherosclerosis burden in the survivors of an asymptomatic elderly cohort study and its relationship to other coronary risk factors (specifically, age) by evaluating aortic atherosclerotic wall burden by magnetic resonance imaging (MRI). Methods A total of 312 participants in an ongoing observational cohort study underwent cardiac and descending thoracic aorta imaging by MRI. Maximum wall thickness was measured and the mean wall thickness calculated. Wall/outer wall ratio was used as a normalized wall index (NWI) adjusted for artery size difference among participants. Percent wall volume (PWV) was calculated as NWI × 100. Results In this asymptomatic cohort (mean age: 76 years), the mean (SD) aortic wall area and wall thickness were 222 ± 45 mm2 and 2.7 ± 0.4 mm, respectively. Maximum wall thickness was 3.4 ± 0.6 mm, and PWV was 32% ± 4%. Women appeared to have smaller wall area, but after correcting for their smaller artery size, had significantly higher PWV than men (P = 0.03). Older age was associated with larger wall area (P = 0.04 for trend) with similar PWVs. However, there were no statistically significant associations between standard risk factors, Framingham global risk, or metabolic syndrome status, therapy for cholesterol or hypertension, coronary or aortic calcium score, and the aortic wall burden. Aortic calcification was associated with coronary calcification. Conclusions Asymptomatic elderly in this cohort had a greater descending thoracic aortic wall volume that correlated with age, and women had a significantly increased PWV compared to men. In these survivors, the atherosclerotic aortic wall burden was not significantly associated with traditional risk factors or with coronary or aortic calcium scores or coronary calcium progression. Results suggest that age, or as yet unidentified risk factor(s), may be responsible for the increase in atherosclerosis.

  19. Aortic Dissection Cases Presenting with Neurological Deficit

    Directory of Open Access Journals (Sweden)

    Sibel Mumcu

    2014-06-01

    Full Text Available Aortic dissection can be fatal in case of underdiagnosis, and early treatment is essential for the survival. Although acute onset of chest or back pain is most common presenting symptoms, some patients might present with atypical findings such as acute stroke, mesenteric ischaemia, renal failure or myocardial infarction. Here, we report two cases presenting emergency room with atypical findings of aortic dissection which diagnosis is made during etiologic work up for ischemic stroke.

  20. Glucose Suppresses Biological Ferroelectricity in Aortic Elastin

    OpenAIRE

    Liu, Yuanming; WANG, YUNJIE; Chow, Ming-Jay; Chen, Nataly Q.; Ma, Feiyue; Zhang, Yanhang; Li, Jiangyu

    2013-01-01

    Elastin is an intriguing extracellular matrix protein present in all connective tissues of vertebrates, rendering essential elasticity to connective tissues subjected to repeated physiological stresses. Using piezoresponse force microscopy, we show that the polarity of aortic elastin is switchable by an electrical field, which may be associated with the recently discovered biological ferroelectricity in the aorta. More interestingly, it is discovered that the switching in aortic elastin is la...

  1. Quantification of abdominal aortic deformation after EVAR

    Science.gov (United States)

    Demirci, Stefanie; Manstad-Hulaas, Frode; Navab, Nassir

    2009-02-01

    Quantification of abdominal aortic deformation is an important requirement for the evaluation of endovascular stenting procedures and the further refinement of stent graft design. During endovascular aortic repair (EVAR) treatment, the aortic shape is subject to severe deformation that is imposed by medical instruments such as guide wires, catheters, and, the stent graft. This deformation can affect the flow characteristics and morphology of the aorta which have been shown to be elicitors for stent graft failures and be reason for reappearance of aneurysms. We present a method for quantifying the deformation of an aneurysmatic aorta imposed by an inserted stent graft device. The outline of the procedure includes initial rigid alignment of the two abdominal scans, segmentation of abdominal vessel trees, and automatic reduction of their centerline structures to one specified region of interest around the aorta. This is accomplished by preprocessing and remodeling of the pre- and postoperative aortic shapes before performing a non-rigid registration. We further narrow the resulting displacement fields to only include local non-rigid deformation and therefore, eliminate all remaining global rigid transformations. Finally, deformations for specified locations can be calculated from the resulting displacement fields. In order to evaluate our method, experiments for the extraction of aortic deformation fields are conducted on 15 patient datasets from endovascular aortic repair (EVAR) treatment. A visual assessment of the registration results and evaluation of the usage of deformation quantification were performed by two vascular surgeons and one interventional radiologist who are all experts in EVAR procedures.

  2. Repositioning of an Intraventricular Dislocated Aortic Valve during Transcatheter Aortic Valve Implantation

    NARCIS (Netherlands)

    Natour, Ehsan; Douglas, Yvonne L.; Jainandunsing, Jayant S.; Schurer, Remco A. J.; van der Werf, Hendrik W.; van den Heuvel, Ad F. M.

    2014-01-01

    The case is presented of a 75-year-old man referred for transcatheter aortic valve implantation. During the procedure the prosthetic aortic valve became dislocated into the left ventricle shortly after expansion. The subsequent steps taken to reposition the valve using only materials at hand are des

  3. Turner's syndrome associated with bicuspid aortic stenosis and dissecting aortic aneurysm

    OpenAIRE

    Slater, D N; Grundman, M. J.; Mitchell, L

    1982-01-01

    A case of Turner's syndrome is described associated with bicuspid aortic stenosis and fatal rupture of a thoracic dissecting aortic aneurysm. Histology of the aneurysm showed severe cystic medial necrosis. This association has not been previously described in the absence of coarctation.

  4. ALTERNATIVE METHOD OF SURGICAL CORRECTION OF DISSECTING AORTIC ANEURYSMS WITH AORTIC INSUFFIECIENCY

    Directory of Open Access Journals (Sweden)

    M. L. Semenovsky

    2009-01-01

    Full Text Available Patients with dissecting aortic aneurysm and associated acute aortic insufficiency form a group of seriously ill patients with significant cardiac failure, generally involving other organs and systems. It justifies an attempt to reduce a surgical risk, by using more sparing procedures, including supracoronary replacement of the ascending aorta with its root reconstruction. The latter has been performed in 27 patients (mean 54,5 ± 2,1 years with dissecting aortic aneurysm and aortic valvular insufficiency in 1996 to 2009. The major etiological factor was atherosclerosis (88%/ Seventeen (63%, 6 (22,2% and 4 (16% had types I, IIA and II dissection, respectively. Overall hospital mortality was 11%. In late period, progressive aneurysm dissection needed reinterventions in 2 cases. The competence of the reconstructed aortic valve was satisfactory both just after surgery and throughout the follow-up. Indications for this option of chronic correction, surgical techniques, and immediate and long-term results are outlined. 

  5. Abdominal Aortic Diameter Is Increased in Males with a Family History of Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Mejnert Jørgensen, Trine; Houlind, K; Green, A;

    2014-01-01

    OBJECTIVE: To investigate, at a population level, whether a family history of abdominal aortic aneurysm (AAA) is independently related to increased aortic diameter and prevalence of AAA in men, and to elucidate whether the mean aortic diameter and the prevalence of AAA are different between...... participants with male and female relatives with AAA. DESIGN: Observational population-based cross-sectional study. MATERIALS: 18,614 male participants screened for AAA in the VIVA-trial 2008-2011 with information on both family history of AAA and maximal aortic diameter. METHODS: Standardized ultrasound scan...... measurement of maximum antero-posterior aortic diameter. Family history obtained by questionnaire. Multivariate regression analysis was used to test for confounders: age, sex, smoking, comorbidity and medication. RESULTS: From the screened cohort, 569 participants had at least one first degree relative...

  6. The clinical application of multi-slice spiral CT angiography in abdominal aortic disease

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective: To evaluate the clinical application of multi-slice spiral CT angiography(MSCTA) in the assessment of abdominal aortic disease. Methods: Fifty-four patients underwent multi-slice spiral CT angiography of abdomen. Contrast agent (Omnipaque 300 I g/L) 1.5 ml/kg was injected and the injection rate was 3 ml/s. The delay time was determined by bolus tracking technique,Tll level abdominal aorta was set as the target vessel and the threshold was 180-200 Hu, slice width was 3 mm and with a pitch of 4-6.Original data were transferred to working-station to perform functional reconstruction. Results: Ten cases were normal, twenty-eight cases were abdominal aortic aneurysms, five abdominal aortic dissecting aneurysms (Debakay type Ⅲ ) and eleven aortic sclerosis. SSD showed the body of aneurysm and the relationship between aneurysm and adjacent blood vessel, MIP better displayed calcification of blood vessel wall and condition of the stent, MPR demonstrated true and false lumen, rupture site of abdominal aorta intima and mural thrombus. Conclusion: MSCTA axial and reconstruction image can show the extent of abdominal aortic disease and the relationship with adjacent blood vessels. It is a safe, simple and non-invasive examination method.

  7. Measurement and determinants of infrarenal aortic thrombus volume

    Energy Technology Data Exchange (ETDEWEB)

    Golledge, Jonathan; Wolanski, Philippe [James Cook University, The Vascular Biology Unit, Townsville, Queensland (Australia); Townsville Hospital, Townsville, Queensland (Australia); Parr, Adam [James Cook University, The Vascular Biology Unit, Townsville, Queensland (Australia); Buttner, Petra [James Cook University, School of Public Health and Tropical Medicine, Townsville, Queensland (Australia)

    2008-09-15

    Intra-luminal thrombus has been suggested to play a role in the progression of abdominal aortic aneurysm (AAA). The aims of this study were twofold. Firstly, to assess the reproducibility of a computer tomography (CT)-based technique for measurement of aortic thrombus volume. Secondly, to examine the determinants of infrarenal aortic thrombus volume in a cohort of patients with aortic dilatation. A consecutive series of 75 patients assessed by CT angiography with maximum aortic diameter {>=}25 mm were recruited. Intra-luminal thrombus volume was measured by a semi-automated workstation protocol based on a previously defined technique to quantitate aortic calcification. Intra- and inter-observer reproducibility were assessed using correlation coefficients, coefficient of variation and Bland-Altman plots. Infrarenal aortic thrombus volume percentage was related to clinical, anatomical and blood characteristics of the patients using univariate and multivariate tests. Infrarenal aortic thrombus volume was related to the severity of aortic dilatation assessed by total aortic volume (r=0.87, P<0.0001) or maximum aortic diameter (r=0.74, P< 0.0001). We therefore examined the clinical determinates of aortic thrombus expressed as a percentage of total aortic volume. Aortic thrombus percentage was negatively correlated with serum high density lipoprotein (HDL, r=-0.31). By ordinal multiple logistic regression analysis serum HDL below median ({<=}1.2 mM) was associated with aortic thrombus percentage in the upper quartile adjusting for other risk factors (odds ratio 5.3, 95% CI 1.1-25.0). Infrarenal aortic thrombus volume can be measured reproducibly on CT. Serum HDL, which can be therapeutically raised, may play a role in discouraging aortic thrombus accumulation with implications in terms of delaying progression of AAA. (orig.)

  8. Bilinearity in spatiotemporal integration of synaptic inputs.

    Directory of Open Access Journals (Sweden)

    Songting Li

    2014-12-01

    Full Text Available Neurons process information via integration of synaptic inputs from dendrites. Many experimental results demonstrate dendritic integration could be highly nonlinear, yet few theoretical analyses have been performed to obtain a precise quantitative characterization analytically. Based on asymptotic analysis of a two-compartment passive cable model, given a pair of time-dependent synaptic conductance inputs, we derive a bilinear spatiotemporal dendritic integration rule. The summed somatic potential can be well approximated by the linear summation of the two postsynaptic potentials elicited separately, plus a third additional bilinear term proportional to their product with a proportionality coefficient [Formula: see text]. The rule is valid for a pair of synaptic inputs of all types, including excitation-inhibition, excitation-excitation, and inhibition-inhibition. In addition, the rule is valid during the whole dendritic integration process for a pair of synaptic inputs with arbitrary input time differences and input locations. The coefficient [Formula: see text] is demonstrated to be nearly independent of the input strengths but is dependent on input times and input locations. This rule is then verified through simulation of a realistic pyramidal neuron model and in electrophysiological experiments of rat hippocampal CA1 neurons. The rule is further generalized to describe the spatiotemporal dendritic integration of multiple excitatory and inhibitory synaptic inputs. The integration of multiple inputs can be decomposed into the sum of all possible pairwise integration, where each paired integration obeys the bilinear rule. This decomposition leads to a graph representation of dendritic integration, which can be viewed as functionally sparse.

  9. Aneurismas da aorta Aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Januário M Souza

    1992-09-01

    Full Text Available Entre janeiro de 1979 e janeiro de 1992, foram realizadas 212 operações para correção de aneurismas e de dissecções da aorta. Neste trabalho serão analisados 104 procedimentos cirúrgicos (em 97 pacientes para correção de aneurismas. A idade dos pacientes variou de 14 a 79 anos (média 59,5 anos e o sexo predominante foi o masculino, com 75 pacientes. Os aneurismas localizavam-se na aorta ascendente em 46 pacientes, na croça em 8, na aorta descendente em 8, na aorta toráco-abdominal em 8, na aorta abdominal em 21, na aorta descendente e abdominal em 2, na aorta ascendente e tóraco-abdominal em 2, na aorta ascendente e descendente em 1, na aorta ascendente, croça e descendente em 1. Doenças cardiovasculares associadas estavam presentes em 39 pacientes, sendo valvopatia aórtica em 18 (excluídos os pacientes com ectasiaânulo-aórtíca, insuficiência coronária em 17, coarctação da aorta em 2, persistência do canal arterial em 1 e valvopatia mitral e aórtica em 1. A mortalidade imediata (hospitalar e/ou 30 dias foi de 14,4%, sendo de 27,7% (5/18 para pacientes com mais de 70 anos e de 11,3% (9/79 para pacientes com idade inferior a 70 anos. Os aneurismas localizados na aorta ascendente e croça foram operados como o auxílio de circulação extracorpórea. Parada circulatória e hipotermia profunda foram utilizadas em todos os pacientes com aneurisma da croça. O estudo tomográfico e angiográfico deve ser de toda a aorta, pela possibilidade de aneurismas de localizações múltiplas.Among 212 patients undergoing operation for aortic aneurysm and aortic dissection between January 1979 and January 1992, 97 were operated on for aneurysms. The aneurysms were localized in: ascending aorta in 46 patients, transverse aortic arch in 8, descending aorta in 8, thoracoabdominal aorta in 8, abdominal (infrarenal aorta in 21, descending and abdominal aorta in 2, ascending and thoracoabdominal aorta in 2, ascending and descending in 1

  10. The Potential Role of Kallistatin in the Development of Abdominal Aortic Aneurysm

    Science.gov (United States)

    Li, Jiaze; Krishna, Smriti Murali; Golledge, Jonathan

    2016-01-01

    Abdominal aortic aneurysm (AAA) is a vascular condition that causes permanent dilation of the abdominal aorta, which can lead to death due to aortic rupture. The only treatment for AAA is surgical repair, and there is no current drug treatment for AAA. Aortic inflammation, vascular smooth muscle cell apoptosis, angiogenesis, oxidative stress and vascular remodeling are implicated in AAA pathogenesis. Kallistatin is a serine proteinase inhibitor, which has been shown to have a variety of functions, potentially relevant in AAA pathogenesis. Kallistatin has been reported to have inhibitory effects on tumor necrosis factor alpha (TNF-α) signaling induced oxidative stress and apoptosis. Kallistatin also inhibits vascular endothelial growth factor (VEGF) and Wnt canonical signaling, which promote inflammation, angiogenesis, and vascular remodeling in various pre-clinical experimental models. This review explores the potential protective role of kallistatin in AAA pathogenesis. PMID:27529213

  11. Mutations in smooth muscle alpha-actin (ACTA2) lead to thoracic aortic aneurysms and dissections.

    Science.gov (United States)

    Guo, Dong-Chuan; Pannu, Hariyadarshi; Tran-Fadulu, Van; Papke, Christina L; Yu, Robert K; Avidan, Nili; Bourgeois, Scott; Estrera, Anthony L; Safi, Hazim J; Sparks, Elizabeth; Amor, David; Ades, Lesley; McConnell, Vivienne; Willoughby, Colin E; Abuelo, Dianne; Willing, Marcia; Lewis, Richard A; Kim, Dong H; Scherer, Steve; Tung, Poyee P; Ahn, Chul; Buja, L Maximilian; Raman, C S; Shete, Sanjay S; Milewicz, Dianna M

    2007-12-01

    The major function of vascular smooth muscle cells (SMCs) is contraction to regulate blood pressure and flow. SMC contractile force requires cyclic interactions between SMC alpha-actin (encoded by ACTA2) and the beta-myosin heavy chain (encoded by MYH11). Here we show that missense mutations in ACTA2 are responsible for 14% of inherited ascending thoracic aortic aneurysms and dissections (TAAD). Structural analyses and immunofluorescence of actin filaments in SMCs derived from individuals heterozygous for ACTA2 mutations illustrate that these mutations interfere with actin filament assembly and are predicted to decrease SMC contraction. Aortic tissues from affected individuals showed aortic medial degeneration, focal areas of medial SMC hyperplasia and disarray, and stenotic arteries in the vasa vasorum due to medial SMC proliferation. These data, along with the previously reported MYH11 mutations causing familial TAAD, indicate the importance of SMC contraction in maintaining the structural integrity of the ascending aorta.

  12. The Potential Role of Kallistatin in the Development of Abdominal Aortic Aneurysm.

    Science.gov (United States)

    Li, Jiaze; Krishna, Smriti Murali; Golledge, Jonathan

    2016-01-01

    Abdominal aortic aneurysm (AAA) is a vascular condition that causes permanent dilation of the abdominal aorta, which can lead to death due to aortic rupture. The only treatment for AAA is surgical repair, and there is no current drug treatment for AAA. Aortic inflammation, vascular smooth muscle cell apoptosis, angiogenesis, oxidative stress and vascular remodeling are implicated in AAA pathogenesis. Kallistatin is a serine proteinase inhibitor, which has been shown to have a variety of functions, potentially relevant in AAA pathogenesis. Kallistatin has been reported to have inhibitory effects on tumor necrosis factor alpha (TNF-α) signaling induced oxidative stress and apoptosis. Kallistatin also inhibits vascular endothelial growth factor (VEGF) and Wnt canonical signaling, which promote inflammation, angiogenesis, and vascular remodeling in various pre-clinical experimental models. This review explores the potential protective role of kallistatin in AAA pathogenesis. PMID:27529213

  13. Vasopressor mechanisms in acute aortic coarctation hypertension

    Directory of Open Access Journals (Sweden)

    Salgado H.C.

    1997-01-01

    Full Text Available Angiotensin II (ANG II and vasopressin (AVP act together with the mechanical effect of aortic constriction in the onset of acute aortic coarctation hypertension. Blockade of ANG II and AVP V1 receptors demonstrated that ANG II acts on the prompt (5 min rise in pressure whereas AVP is responsible for the maintenance (30-45 min of the arterial pressure elevation during aortic coarctation. Hormone assays carried out on blood collected from conscious rats submitted to aortic constriction supported a role for ANG II in the early stage and a combined role for both ANG II and AVP in the maintenance of proximal hypertension. As expected, a role for catecholamines was ruled out in this model of hypertension, presumably due to the inhibitory effect of the sinoaortic baroreceptors. The lack of afferent feedback from the kidneys for AVP release from the central nervous system in rats with previous renal denervation allowed ANG II to play the major role in the onset of the hypertensive response. Median eminence-lesioned rats exhibited a prompt increase in proximal pressure followed by a progressive decline to lower hypertensive levels, revealing a significant role for the integrity of the neuroaxis in the maintenance of the aortic coarctation hypertension through the release of AVP. In conclusion, the important issue raised by this model of hypertension is the likelihood of a link between some vascular territory - probably renal - below the coarctation triggering the release of AVP, with this vasoconstrictor hormone participating with Ang II and the mechanical effect of aortic constriction in the acute aortic coarctation hypertension

  14. Atherosclerotic Aortic Plaques Detected by Transesophageal Echocardiography

    Institute of Scientific and Technical Information of China (English)

    赵云; 朱文玲; 倪超; 郭丽琳; 曾勇; 方理刚

    2002-01-01

    Objective To evaluate the predictive value of atherosclerotic aortic plaques in coronary artery disease (CAD) Methods In 50patients with suspected coronary artery disease, transesophageal echocardiography was performed to examine their thoracic aortas 2 weeks before or after coronary angiography. In the cases of coronary angiography studied, stenosis of the coronary artery ≥ 50 % was considered to be due to coronary artery disease,whereas the thickness of the intima ≥ 1.3 mm was taken to be the criteria for the presence of an atherosclerotic aortic plaque on the transesophageal echocardiographic test. Results Among the 50 patients, 37 cases were diagnosed as CAD and 13 cases were considered to be normal. The plaques of the thoracic aorta were observed in 34cases in the CAD group and 3 cases in the normal group. The sensitivity and specificity of aortic plaques for CAD were 91.9 % and 76.9%, respectively. The positive and negative predictive values of the aortic plaques for CAD were 91.9% and 76.9%, respectively. The accuracy was 88.0%. 80 percent of the patients with single- yes sel disease had thoracic aortic plaques, 92 percent of the patients with two-vessel disease and 100 percent of the patients with three-vessel disease had thoracic aortic plaques. There was a significant difference in the thickness of aortic intimas between the normal group and the CAD group. Conclusions Detectingatherosclerotic plaques in the thoracic aorta with transesophageal echocardiography may be of great value in predicting the presence and extent of coronary artery disease.

  15. Controlling methods of a newly developed extra aortic counter-pulsation device using shape memory alloy fibers.

    Science.gov (United States)

    Hashem, Mohamed O; Yamada, A; Tsuboko, Y; Muira, H; Homma, D; Shiraishi, Y; Yambe, T

    2013-01-01

    Diastolic counter-pulsation has been used to provide circulatory augmentation for short term cardiac support. The success of intra-aortic balloon pump (IABP) therapy has generated interest in long term counter-pulsation strategies to treat heart failure patients. The authors have been developing a totally implantable extra aortic pulsation device for the circulatory support of heart failure patients, using 150 µm Ni-Ti anisotropic shape memory alloy (SMA) fibers. These fibers contract by Joule heating with an electric current supply. The special features of our design are as follow: non blood contacting, extra aortic pulsation function synchronizing with the native heart, a wrapping mechanical structure for the aorta in order to achieve its assistance as the aortomyoplsty and the extra aortic balloon pump. The device consisted of rubber silicone wall plates, serially connected for radial contraction. We examined the contractile function of the device, as well as it controlling methods; the phase delay parameter and the pulse width modulation, in a systemic mock circulatory system, with a pneumatically driven silicone left ventricle model, arterial rubber tubing, a peripheral resistance unit, and a venous reservoir. The device was secured around the aortic tubing with a counter-pulsation mode of 1:4 against the heartbeat. Pressure and flow waveforms were measured at the aortic outflow, as well as its driving condition of the contraction phase width and the phase delay. The device achieved its variable phase control for co-pulsation or counter-pulsation modes by changing the phase delay of the SMA fibers. Peak diastolic pressure significantly augmented, mean flow increased (p<0.05) according to the pulse width modulation. Therefore the newly developed extra aortic counter-pulsation device using SMA fibers, through it controlling methods indicated its promising alternative extra aortic approach for non-blood contacting cardiovascular circulatory support.

  16. Comprehensible input and learning outcomes

    OpenAIRE

    Salazar Campillo, Patricia

    1996-01-01

    Segones Jornades de Foment de la Investigació de la FCHS (Any 1996-1997) In Krashen’s terms, optimal input has to be comprehensible to the learner if we want acquisition to take place. An overview of the literature on input indicates two ways of making input comprehensible: the first one is to premodify input before it is offered to the learner, (premodified input), and the second one is to negotiate the input through interaction (interactionally modified input). The aim of the...

  17. Perioperative management of endovascular abdominal aortic aneurysm repair

    International Nuclear Information System (INIS)

    Objective: To summarize the clinical experience of perioperative management in performing endovascular abdominal aortic aneurysm repair (EVAR). Methods: EVAR was performed in 22 patients with abdominal aortic aneurysm. The clinical data were retrospectively analyzed. Before treatment the functions of main organs were evaluated and certain measures were adopted in order to protect them. Useful parameters, including the length, diameter, angle and configuration of the proximal and distal aneurysmal neck, the relationship of the aneurysm to aortic branches, the distance from the lowest renal artery to the bifurcation of abdominal aorta, and the quality of access vessels (such as diameter, tortuosity and calcification degree) were determined and assessed with CTA. According to the parameters thus obtained, the suitable stent-graft with ideal diameter and length was selected, and the optimal surgery pattern was employed. Local anesthesia was employed in 20 patients, among them the local anesthesia had to be changed to general anesthesia in one. Epidural anesthesia was carried out in one patient through the surgically-reconstructed iliac artery access,and general anesthesia was employed in one patient who had Stanford type A aortic dissection. The lowest renal artery must be accurately localized before deployment of stent-graft was started. At least one patent internal iliac artery should be reserved when bilateral internal iliac arteries needed to be covered, to be covered by stages or to be reconstructed. After stent-graft placement, angiography must be performed to find out if there was any endoleak and, if any, to determine the type of endoleak and to deal with it properly. Two cases had proximal type I endoleak, so balloon dilation was employed in one and cuff implantation in another one. Distal type I endoleak occurred in one case, but, unfortunately, the iliac artery ruptured when balloon dilation was employed, therefore the patient had to receive vascular repair

  18. RELIABILITY ANALYSIS OF CORRELATED INPUT VARIABLES BASED ON COPULA FUNCTION IN GENERALIZED RANDOM SPACE%基于Copula函数的广义随机空间内相关变量的可靠性分析

    Institute of Scientific and Technical Information of China (English)

    申焱华; 石博强

    2011-01-01

    非正态相关变量的产品可靠性分析,需要应用变量间的联合概率密度函数进行转换.然而,实际工程中由于概率信息的不完备,难以求取准确的联合概率密度函数,而变量的边缘分布及其相关关系易于得到.文中采用Copula函数,利用变量的边缘分布以及相关关系,构造出系统的联合概率密度函数.同时指出,目前常用的Nataf变换只是基于Copula变换的一种特例.基于Copula函数的可靠性分析能更精确地描述实际情况,是一种基于非线性相关的模型,使问题的解决更加方便、灵活.%In reliability-based analysis of complex product with non-Gaussian, correlated input variables, a joint probability distribution function (PDF) is required to transform the correlated input variables into independent standard Gaussian variables. However, in practical industry application, a joint probability distribution function is difficult to be constructed for the related probability information is non-complete. However, the information about the n-dimensional correlated variables (such as the marginal PDF and covariance matrix) can be achieved easily. So Copula function is introduced to build the joint PDF using the marginal PDF and covariance matrix. It is demonstrated that the Nataf transformation is one of Copulas. Copula transformation can deal with the non-linear correlated relationship. The reliability analysis results based on Copula are more applicable and accurate by numerical example.

  19. External aortic wrap for repair of type 1 endoleak

    Directory of Open Access Journals (Sweden)

    Anastasia Dean

    2014-01-01

    CONCLUSION: Provided certain anatomical features are present, an external aortic wrap is a useful and successful option to manage type 1 endoleak in high-risk patients who are unsuitable for aortic clamping.

  20. Outcomes after transcatheter aortic valve implantation: transfemoral versus transapical approach

    NARCIS (Netherlands)

    Ewe, S.H.; Delgado, V.; Ng, A.C.; Antoni, M.L.; Kley, F. van der; Marsan, N.A.; Weger, A. de; Tavilla, G.; Holman, E.R.; Schalij, M.J.; Bax, J.J.

    2011-01-01

    BACKGROUND: Transcatheter aortic valve implantation is commonly implanted through a transfemoral (TFA) or transapical approach (TAA) for patients with severe aortic stenosis. This study aimed to describe the clinical and echocardiographic outcomes of TFA versus TAA. METHODS: Clinical and echocardiog

  1. 70 input, 20 nanosecond pattern classifier

    OpenAIRE

    Masa, P.; Hoen, K.; Wallinga, H.

    1994-01-01

    A CMOS neural network integrated circuit is discussed, which was designed for very high speed applications. This full-custom, mixed analog-digital chip implements a fully connected feedforward neural network with 70 inputs, 6 hidden layer neurons and one output neuron. The neurons perform inner product operation and have a sigmoid-like activation function. The 70 network inputs and the neural signal processing are analog, the synaptic weights are digitally programmable with 5 bit (4 bits+sign...

  2. Access to Research Inputs

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Grimpe, Christoph; Pellens, Maikel

    2015-01-01

    The viability of modern open science norms and practices depends on public disclosure of new knowledge, methods, and materials. However, increasing industry funding of research can restrict the dissemination of results and materials. We show, through a survey sample of 837 German scientists in life...... sciences, natural sciences, engineering, and social sciences, that scientists who receive industry funding are twice as likely to deny requests for research inputs as those who do not. Receiving external funding in general does not affect denying others access. Scientists who receive external funding...

  3. Access to Research Inputs

    DEFF Research Database (Denmark)

    Czarnitzki, Dirk; Grimpe, Christoph; Pellens, Maikel

    The viability of modern open science norms and practices depend on public disclosure of new knowledge, methods, and materials. However, increasing industry funding of research can restrict the dissemination of results and materials. We show, through a survey sample of 837 German scientists in life...... sciences, natural sciences, engineering, and social sciences, that scientists who receive industry funding are twice as likely to deny requests for research inputs as those who do not. Receiving external funding in general does not affect denying others access. Scientists who receive external funding...

  4. Is there alteration in aortic stiffness in Leber hereditary optic neuropathy?

    NARCIS (Netherlands)

    Nemes, A.; Coo, I.F.M. de; Spruijt, L.; Smeets, H.J.; Chinnery, P.F.; Soliman, O.I.; Geleijnse, M.L.; Cate, FJ Ten

    2008-01-01

    PURPOSE: Leber hereditary optic neuropathy (LHON) is recognized as the most common cause of isolated blindness in young men. The current study was designed to test whether LHON as a mitochondrial disease is associated with vascular functional alterations characterized by aortic elastic properties du

  5. Myocardial infarction with aortic banding - A combined rat model of heart failure

    NARCIS (Netherlands)

    Anthonio, RL; vanVeldhuisen, DJ; vanBekkum, C; deBoer, E; vanGilst, WH

    1997-01-01

    The effect of additional abdominal aortic banding on parameters of heart failure was studied in male Wistar rats with myocardial infarction. Contractile function was studied 8-9 weeks after operation, with an isoprenaline dose response protocol, in a retrograde Langendorff perfusion. Also, plasma no

  6. The Early Variation of Left Ventricular Strain after Aortic Valve Replacement by Three-Dimensional Echocardiography.

    Directory of Open Access Journals (Sweden)

    Yongle Chen

    Full Text Available Aortic stenosis (AS and aortic incompetence (AI are common aortic valve diseases. Both may deteriorate into irreversible myocardial dysfunction and will increase the risk of sudden death. In this study, we aimed to investigate the early variation trend of left ventricular function by three-dimensional speckle tracking echocardiography (3D-STE in the patients who underwent cardiac surgeries for aortic valve disease. Twenty patients with severe aortic AS and 16 patients with severe AI were enrolled. All of them underwent the aortic valve replacement (AVR procedures. The patients' global longitudinal strain (GLS and global circumferential strain (GCS were evaluated by 3D-STE before surgery and at 1 week after surgery. In addition, GLS and GCS were followed at 1 month as well as 3 months after AVR. In AS patients, the GCS after AVR altered little both at 1 week (p = 0.562 and at 1 month (p = 0.953 compared with the data before the surgery. And it increased significantly at 3 months of follow-up observation compared to that before AVR (p<0.05. Meanwhile, GLS increased progressively after AVR and improved significantly at 3 months after surgery (p<0.05. For the AI patients, GLS as well as GCS decreased at 1 week after AVR compared to those data at baseline (p<0.05. However, these two parameters recovered at 1 month after AVR. Furthermore, GLS and GCS improved significantly at 3 months after the surgery (p<0.05. Therefore, both GLS and GCS were influenced by AVR and would be improved at 3 months after surgery both in AS patients or AI patients. GLS and GCS can be finely evaluated by 3D-STE, and they are helpful to determine the variation tendency of left ventricular function in patients with AVR.

  7. The German Aortic Valve Registry (GARY): in-hospital outcome

    OpenAIRE

    Hamm, Christian W.; Möllmann, Helge; Holzhey, David; Beckmann, Andreas; Veit, Christof; Figulla, Hans-Reiner; Cremer, J; Kuck, Karl-Heinz; Lange, Rüdiger; Zahn, Ralf; Sack, Stefan; Schuler, Gerhard; Walther, Thomas; Beyersdorf, Friedhelm; Böhm, Michael

    2013-01-01

    Background Aortic stenosis is a frequent valvular disease especially in elderly patients. Catheter-based valve implantation has emerged as a valuable treatment approach for these patients being either at very high risk for conventional surgery or even deemed inoperable. The German Aortic Valve Registry (GARY) provides data on conventional and catheter-based aortic procedures on an all-comers basis. Methods and results A total of 13 860 consecutive patients undergoing repair for aortic valve d...

  8. A Clinicopathological Study on Aortic Valves in Children

    Institute of Scientific and Technical Information of China (English)

    HUANG Ping; WANG Hongwei; ZHANG Zhenlu; HU Xiufen; LI Yanping; CHENG Peixuan; LIU Jianying

    2007-01-01

    In order to investigate the clinicopathological characteristics of aortic valve disease in children, all the native surgically excised aortic valves obtained between January 2003 and December 2005 were studied macroscopically and microscopically. The patients' medical records were reviewed and the clinical information was extracted. According to preoperative echocardiography, intraoperative assessment, and postoperative pathology, combined with clinical symptoms and signs, aortic valve diseases were divided into three categories: aortic stenosis (AS), aortic insufficiency (AI), and aortic stenosis with insufficiency (AS-AI). The etiology was determined according to the macroscopic, microscopic and clinical findings. The results showed that among 70 aortic valves, patient age ranged from 6 to 18 years, with a mean of 15.4 years, and there were 56 boys and 14 girts (male: female=4:1). Forty-four children only had pure aortic valve disease, and the other 26 children had aortic valve disease associated with other heart valve diseases. There were 5 cases of AS (7.14%), 60 cases of AI (85.71%) and 5 cases of AS-AI (7.14%). The causes were congenital aortic valve malformation (32 cases, 45.71%), rheumatic disease (28 cases, 40%), infective endocarditis (7 cases,10%), Marfan syndrome (2 cases, 2.86%), and undetermined (1 case, 1.43%). It was concluded that the common causes of aortic valve disease in order of frequency in children were congenital aortic valve malformation, rheumatic disease, infective endocarditis, and Marfan syndrome. AI was more common in children with aortic valve disease. Compared with adult patients, congenital bicuspid aortic valve in children was often AI. Histologically, the leaflets of congenital bicuspid aortic valve were mainly myxomatous, fibrosis and calcification less seen. AI was frequently found in rheumatic disease, mostly associated with other heart valve diseases. Macroscopic and microscopic examinations together with clinical

  9. Efeitos da atorvastatina, fluvastatina, pravastatina e simvastatina sobre a função endotelial, a peroxidação lipídica e a aterosclerose aórtica em coelhos hipercolesterolêmicos Effects of atorvastatin, fluvastatin, pravastatin, and simvastatin on endothelial function, lipid peroxidation, and aortic atherosclerosis in hypercholesterolemic rabbits

    Directory of Open Access Journals (Sweden)

    Paulo Afonso Ribeiro Jorge

    2005-04-01

    Full Text Available OBJETIVO: Comparar os efeitos da atorvastatina, fluvastatina, pravastatina e simvastatina sobre a função endotelial, a aterosclerose aórtica e o teor de malonodialdeído (MDA nas LDL nativas, oxidadas e na parede arterial de coelhos hipercolesterolêmicos, depois que as doses destas estatinas foram ajustadas para reduzir o colesterol total plasmático a valores similares. MÉTODOS: Coelhos machos, foram separados em grupos de 10 animais (n=10, chamados hipercolesterolêmico (controle, atorvastatina, fluvastatina, pravastatina e normal. A exceção do grupo normal, os animais foram alimentados com ração padrão acrescida de colesterol a 0,5% e óleo de coco a 2% durante 45 dias. As drogas foram administradas a partir do 15º dia do início do experimento e no 30º dia, as doses foram ajustadas, através do controle do colesterol plasmático, para obter valores semelhantes em cada grupo. Ao final do experimento foi dosado o colesterol plasmático e as lipoproteinas e retirado um segmento de aorta torácica para estudo da função endotelial, da peroxidação lipídica e exame histológico para medida da aterosclerose aórtica. RESULTADOS: As estatinas reduziram significantemente o colesterol total plasmático, as LDL-colesterol e a aterosclerose aórtica. O teor de MDA também foi significantemente reduzido nas LDL nativas e oxidadas, assim como na parede arterial. O relaxamento-dependente do endotélio foi significantemente maior no grupo tratado em comparação ao hipercolesterolêmico. CONCLUSÃO: As estatinas, em doses ajustadas, tiveram efeito significante e similar em reduzir a peroxidação lipídica nas LDL e na parede arterial, na regressão da aterosclerose aórtica e na reversão da disfunção endotelial.OBJECTIVE: To compare the effects of atorvastatin, fluvastatin, pravastatin, and simvastatin on endothelial function, aortic atherosclerosis, and the content of malondialdehyde (MDA in native and oxidized LDL and in the arterial

  10. Input or intimacy

    Directory of Open Access Journals (Sweden)

    Judit Navracsics

    2014-01-01

    Full Text Available According to the critical period hypothesis, the earlier the acquisition of a second language starts, the better. Owing to the plasticity of the brain, up until a certain age a second language can be acquired successfully according to this view. Early second language learners are commonly said to have an advantage over later ones especially in phonetic/phonological acquisition. Native-like pronunciation is said to be most likely to be achieved by young learners. However, there is evidence of accentfree speech in second languages learnt after puberty as well. Occasionally, on the other hand, a nonnative accent may appear even in early second (or third language acquisition. Cross-linguistic influences are natural in multilingual development, and we would expect the dominant language to have an impact on the weaker one(s. The dominant language is usually the one that provides the largest amount of input for the child. But is it always the amount that counts? Perhaps sometimes other factors, such as emotions, ome into play? In this paper, data obtained from an EnglishPersian-Hungarian trilingual pair of siblings (under age 4 and 3 respectively is analyzed, with a special focus on cross-linguistic influences at the phonetic/phonological levels. It will be shown that beyond the amount of input there are more important factors that trigger interference in multilingual development.

  11. Measuring Input Thresholds on an Existing Board

    Science.gov (United States)

    Kuperman, Igor; Gutrich, Daniel G.; Berkun, Andrew C.

    2011-01-01

    A critical PECL (positive emitter-coupled logic) interface to Xilinx interface needed to be changed on an existing flight board. The new Xilinx input interface used a CMOS (complementary metal-oxide semiconductor) type of input, and the driver could meet its thresholds typically, but not in worst-case, according to the data sheet. The previous interface had been based on comparison with an external reference, but the CMOS input is based on comparison with an internal divider from the power supply. A way to measure what the exact input threshold was for this device for 64 inputs on a flight board was needed. The measurement technique allowed an accurate measurement of the voltage required to switch a Xilinx input from high to low for each of the 64 lines, while only probing two of them. Directly driving an external voltage was considered too risky, and tests done on any other unit could not be used to qualify the flight board. The two lines directly probed gave an absolute voltage threshold calibration, while data collected on the remaining 62 lines without probing gave relative measurements that could be used to identify any outliers. The PECL interface was forced to a long-period square wave by driving a saturated square wave into the ADC (analog to digital converter). The active pull-down circuit was turned off, causing each line to rise rapidly and fall slowly according to the input s weak pull-down circuitry. The fall time shows up as a change in the pulse width of the signal ready by the Xilinx. This change in pulse width is a function of capacitance, pulldown current, and input threshold. Capacitance was known from the different trace lengths, plus a gate input capacitance, which is the same for all inputs. The pull-down current is the same for all inputs including the two that are probed directly. The data was combined, and the Excel solver tool was used to find input thresholds for the 62 lines. This was repeated over different supply voltages and

  12. Rapid prototyping in aortic surgery.

    Science.gov (United States)

    Bangeas, Petros; Voulalas, Grigorios; Ktenidis, Kiriakos

    2016-04-01

    3D printing provides the sequential addition of material layers and, thus, the opportunity to print parts and components made of different materials with variable mechanical and physical properties. It helps us create 3D anatomical models for the better planning of surgical procedures when needed, since it can reveal any complex anatomical feature. Images of abdominal aortic aneurysms received by computed tomographic angiography were converted into 3D images using a Google SketchUp free software and saved in stereolithography format. Using a 3D printer (Makerbot), a model made of polylactic acid material (thermoplastic filament) was printed. A 3D model of an abdominal aorta aneurysm was created in 138 min, while the model was a precise copy of the aorta visualized in the computed tomographic images. The total cost (including the initial cost of the printer) reached 1303.00 euros. 3D imaging and modelling using different materials can be very useful in cases when anatomical difficulties are recognized through the computed tomographic images and a tactile approach is demanded preoperatively. In this way, major complications during abdominal aorta aneurysm management can be predicted and prevented. Furthermore, the model can be used as a mould; the development of new, more biocompatible, less antigenic and individualized can become a challenge in the future. PMID:26803324

  13. Endovascular repair of abdominal aortic aneurysms.

    Science.gov (United States)

    Arnaoutakis, Dean J; Zammert, Martin; Karthikesalingam, Alan; Belkin, Michael

    2016-09-01

    Endovascular repair of abdominal aortic aneurysms is an important technique in the vascular surgeon's armamentarium, which has created a seismic shift in the management of aortic pathology over the past two decades. In comparison to traditional open repair, the endovascular approach is associated with significantly improved perioperative morbidity and mortality. The early survival benefit of endovascular abdominal aortic aneurysm repair is sustained up to 3 years postoperatively, but longer-term life expectancy remains poor regardless of operative modality. Nonetheless, most abdominal aortic aneurysms are now repaired using endovascular stent grafts. The technology is not perfect as several postoperative complications, namely endoleak, stent-graft migration, and graft limb thrombosis, can develop and therefore lifelong imaging surveillance is required. In addition, a postoperative inflammatory response has been documented after endovascular repair of aortic aneurysms; the clinical significance of this finding has yet to be determined. Subsequently, the safety and applicability of endovascular stent grafts are likely to improve and expand with the introduction of newer-generation devices and with the simplification of fenestrated systems. PMID:27650343

  14. Challenging Friesian horse diseases : aortic rupture and megaesophagus

    NARCIS (Netherlands)

    Ploeg, M.

    2015-01-01

    Aortic rupture is quite rare in Warmblood horses and is best known as an acute and fatal rupture of the aortic root in older breeding stallions. It has now become clear that aortic rupture, which is diagnosed around an age of 4 years, is more frequent in the Friesian breed than in others. The high p

  15. Aneurysm sac enlargement after endovascular Abdominal Aortic Aneurysm repair

    NARCIS (Netherlands)

    Dingemans, Siem A; Jonker, Frederik H W; Moll, Frans L; van Herwaarden, JA

    2015-01-01

    The aim of this study is to give an overview of current knowledge regarding abdominal aortic aneurysm (AAA) growth after endovascular aortic aneurysm repair (EVAR) that could potentially lead to aortic rupture. A search on Pubmed was performed. A total of 705 articles were found after initial search

  16. Immediate post-operative responses to transcatheter aortic valve implantation

    DEFF Research Database (Denmark)

    Egerod, Ingrid; Nielsen, Susanne; Lisby, Karen H.;

    2015-01-01

    Background:Conventional treatment for patients with severe symptomatic aortic stenosis is surgical aortic valve replacement (SAVR), but transcatheter aortic valve implantation (TAVI) has become a reliable alternative in high-risk patients.Aims:The aim of our study was to describe the post...

  17. Study of Coronary Artery Disease in Single Aortic Valvular Disease

    Institute of Scientific and Technical Information of China (English)

    张斌; 杨伟民; 占亚平

    2003-01-01

    Objectives To analyze the results of coronary angiographies (GAG) in patients with single aortic valvular heart disease; To study the relationship between aortic valve diseases and coronary artery disease (CAD). Methods 105 patients with single aortic valvular heart disease before surgery underwent angiography. The data of clinical characteristics and angiographies were analyzed. Results 51 patients had symptoms of angina pectoris among 105 patients with single aortic valvular heart disease. Seven of them were confirmed coronary artery disease by angiographies. Although the incidence of angina in aortic valve stenosis group was significantly higher than that in aortic valve regurgitation, the probability of combination of CAD in aortic valve stenosis group was similar to the later. However, the probability of combination of CAD in degenerative aortic valve group was significantly higher than the groups of rheumatic, congenitally bicuspid aortic valves, and other causes (p <0.01).Conclusions Angina pectoris is not sensitive for diagnosis of CAD in single aortic valve heart disease.The probability of combination of CAD in degenerative aortic valve disease is higher than that in aortic valve disease with other causes. Coronary angiography is strongly suggested for these patients.

  18. Balloon aortic valvuloplasty in pregnancy with severe aortic stenosis and infective endocarditis

    Directory of Open Access Journals (Sweden)

    Vinotha

    2012-12-01

    Full Text Available Twenty seven year old lady, previously diagnosed to have aortic stenosis, presented to the obstetric outpatient department at 19 weeks of gestation with fever and breathlessness, NYHA class 4, for one week. Two D Echo revealed left ventricular hypertrophy, a severely stenosed, calcified bicuspid aortic valve, with vegetations on aortic and mitral valves and severe mitral regurgitation. Blood cultures grew nutrionally variant streptococci and she was treated with crystalline penicillin and gentamicin. She stabilised clinically by 21 weeks, by which time, the risk of termination of pregnancy was comparable to continuing the pregnancy. She underwent balloon aortic valvuloplasty. Post balloon aortic valvuloplasty, she was stable. At 34+2 weeks, she underwent emergency LSCS, the indication being intrauterine growth restriction with fetal compromise and breech presentation. She delivered a baby girl, 1.6 kg, Apgar 9 & 10. Our case report highlights the fact that a timely, balloon aortic valvuloplasty can be life saving for patients with pregnancy complicated by severe aortic stenosis and infective endocarditis. [Int J Reprod Contracept Obstet Gynecol 2012; 1(1.000: 69-71

  19. Fenestrated endovascular aortic repair for juxtarenal abdominal aortic aneurysm

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; ZHANG Hong-peng; LIU Xiao-ping; JIA Xin; XIONG Jiang; MA Xiao-hui

    2013-01-01

    Background Endovascular stent-graft with fenestration can improve proximal sealing in patients with juxtarenal abdominal aortic aneurysm (JAAA).The purpose of this study was to describe our primary experience and evaluate the safety and efficacy of fenestrated device for JAAA in high-risk patients.Methods Between March 2011 and May 2012,nine male patients (mean age,(79.6±8.6) years) with asymptomatic JAAAs underwent elective deployment of the Zenith fenestrated stent-grafts at a single institution.All patients were treated in the hybrid operating room under general anesthesia.Follow-up computed tomography angiography (CTA) was routinely performed before discharge,at 3,6,and 12 months and annually thereafter.Results Procedural success was achieved in all cases.Total sixteen small fenestrations,two large fenestrations and eight scallops were used.Intra-operative complications occurred in four patients,which included one proximal type Ⅰ endoleak,two type Ⅱ endoleaks,and one renal artery dissection.The mean hospital stay was (8.9±1.4) days,mean blood loss was (360.5±46.8) ml,and mean iodinated contrast volume was (230.6±58.3) ml.The mean follow-up time was (7.6±4.2) months.The visceral graft patency was 100% until now.One patient had an increase of serum creatinine of more than 30%,but did not require dialysis.No patients died,no stent fractured,and migration were diagnosed during the follow-up.Conclusions The early results of fenestrated device for high-risk patients with complex JAAAs are satisfactory.However,long-term fenestrated graft durability and branch vessel patency remain to be determined.

  20. Influence of aerobic exercise training on post-exercise responses of aortic pulse pressure and augmentation pressure in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Nobuhiko eAkazawa

    2015-10-01

    Full Text Available Central arterial blood pressure (BP is more predictive of future cardiovascular events than is brachial BP because it reflects the BP load imposed on the left ventricle with greater accuracy. However, little is known about the effects of exercise training on central hemodynamic response to acute exercise. The purpose of the present study was to determine the influence of an aerobic exercise regimen on the response of aortic BP after a single aerobic exercise in postmenopausal women. Nine healthy postmenopausal women (age: 61 ± 2 years participated in a 12-week aerobic exercise training regimen. Before and after the training, each subjects performed a single bout of cycling at ventilatory thresholds for 30 min. We evaluated the post-exercise aortic BP response, which was estimated via the general transfer function from applanation tonometry. After the initial pre-training aerobic exercise session, aortic BP did not change significantly: however, aortic pulse pressure and augmentation pressure were significantly attenuated after the single aerobic exercise session following the 12-week training regimen. The present study demonstrated that a regular aerobic exercise training regimen induced the post-exercise reduction of aortic pulse pressure and augmentation pressure. Regular aerobic exercise training may enhance post-exercise reduction in aortic BP.

  1. The future of aortic surgery in Europe

    DEFF Research Database (Denmark)

    Czerny, Martin; Bachet, Jean; Bavaria, Joseph;

    2012-01-01

    At least every ten years, each specialty should reflect upon its past, its present and its future, in order to be able to reconfirm the direction in which it is headed, to adopt suggestions from inside and outside and, consequently, to improve. As such, the aim of this manuscript is to provide th...... in Europe, namely the Vascular Domain of the European Association of Cardio-Thoracic Surgery (EACTS)....... the interested reader with an overview of how aortic surgery and (perhaps more accurately) aortic medicine has evolved in Europe, and its present standing; also to provide a glimpse into the future, trying to disseminate the thoughts of a group of people actively involved in the development of aortic medicine...

  2. ED 02-1 ACUTE AORTIC SYNDROME.

    Science.gov (United States)

    Song, Jae-Kwan

    2016-09-01

    The successful clinical introduction of various non-invasive imaging modalities has contributed to the establishment of 'acute aortic syndrome', a relatively new clinical syndrome incorporating several disease entities with similar clinical features (at the time of clinical presentation). Aortic dissection (AD) with intimal flap and two aortic channels (true and false lumens) is the most important disease entity in acute aortic syndrome. Clinical characteristics of AD have been established, with standardized treatment strategies depending on the affected site of the aorta. For the past several decades, variant forms of classic AD, including aortic intramural hematoma (IMH) and incomplete dissection, have been increasingly diagnosed in routine clinical practice worldwide, and imaging findings characteristic of these variant forms have been established for their differential diagnosis. As imaging findings, rather than clinical features, are critical for the differential diagnosis of acute aortic syndrome, careful interpretation of imaging results is necessary for accurate diagnosis and better clinical decision-making, thus improving patient outcomes. IMH is probably the most important variant form of classic AD and has been the source of intense controversy regarding its pathogenesis and optimal treatment options. Clinical reports regarding outcomes of patients with IMH from different centers have shown conflicting results and risk stratification based on imaging findings remains a challenging clinical issue.Intimal tears can have a very wide spectrum. For example, a stellate or linear intimal tear can involve the exposure of the underlying aortic media or adventitial layers but without the progression and separation of the medial layers, resulting in extensive undermining of the intimal layers. This incomplete dissection, characterized by an intimal tear without an intimal flap or hematoma, was reported to be present in 9 of 181 (5%) consecutive patients with

  3. Acute Aortic Dissection Extending Into the Lung.

    Science.gov (United States)

    Makdisi, George; Said, Sameh M; Schaff, Hartzell V

    2015-07-01

    The radiologic manifestations of ruptured acute aortic dissection, Stanford type A aortic dissection, DeBakey type 1 can present in different radiographic scenarios with devastating outcomes. Here, we present a rare case of a 70-year-old man who presented to the emergency department with chest pain radiating to the back. A chest computed tomography scan showed a Stanford type A, DeBakey type 1, acute aortic dissection ruptured into the aortopulmonary window and stenosing the pulmonary trunk, both main pulmonary arteries, and dissecting the bronchovascular sheaths and flow into the pulmonary interstitium, causing pulmonary interstitial hemorrhage. The patient underwent emergent ascending aorta replacement with hemiarch replacement with circulatory arrest. The postoperative course was unremarkable. PMID:26140779

  4. Temporary extracorporeal bypass modalities during aortic surgery.

    Science.gov (United States)

    Bassin, Levi; Bell, David

    2016-09-01

    The key to aortic surgery is protection of the brain, heart, spinal cord, and viscera. For operations involving the aortic arch, the focus is on cerebral protection, while for pathology involving the descending thoracic aorta, the focus is on spinal protection. Optimal cerebral and spinal protection requires an extensive knowledge of the operative steps and an understanding of the cardiopulmonary bypass modalities that are possible. A bloodless field is required when operating on the aorta. As a result, periods of ischemia to the central nervous system and end-organ viscera are often unavoidable. The main techniques to mitigate ischemia include hypothermia and selective perfusion of the ischemic organ in question. This chapter will first briefly review bypass modalities and then describe how they can be used for various aortic scenarios. PMID:27650344

  5. Transcatheter CoreValve valve-in-valve implantation in a stentless porcine aortic valve for severe aortic regurgitation

    OpenAIRE

    Yong, Celina M; Buchbinder, Maurice; Giacomini, John C

    2014-01-01

    Key Clinical Message We describe the first valve-in-valve Corevalve transcatheter aortic valve replacement in the St. Jude Toronto stentless porcine aortic valve in the United States, which enabled this 59-year-old patient with a history of bacterial endocarditis and aortic regurgitation to avoid heart transplant with complete resolution of his severe left ventricular dysfunction.

  6. Diagnostic imaging of acute aortic dissection

    International Nuclear Information System (INIS)

    One hundred and nineteen patients with aortic dissection who underwent diagnostic imaging were reviewed and angiographic findings as well as those of CT were analysed. Thirty eight cases (43.1%) had non-contrast opacified false lumen, the type of which we call 'thrombosed type aortic dissection'. A comparative study of the thrombosed type with the patent type of false lumens was made particularly from the stand point of the characteristic diagnostic imagings (CT and angiography). At the same time, the pitfalls of these imagings in thrombosed type aortic dissection were studied. At the onset the average age of thrombosed type was 62.3 years old, while that of the patent type was 57.3. A statistical significance between the two groups was p<0.05. Thrombosed type in all cases was caused by atherosclerosis, whereas patent type was caused by the Marfan's syndrome in 11 cases. Other clinical findings, such as initial symptoms and blood pressure revealed no significant differences between the two groups. Pre-contrast CT in acute thrombosed type aortic dissection showed 'hyperdense crescent sign' in 89.4%. However, in 3 cases with thrombosed type in which the pre-contrast CT showed 'hyperdense crescent sign' contrast-enhanced CT detected no clear evidence of aortic dissection in the same site. This was due to obscurity induced by contrast medium. Angiographic findings of thrombosed type were classified into 3 groups: normal type, stenosed true lumen type and ulcer-like projection type. The incidence of normal type was estimated to be 48.4%, whereas stenosed true lumen type was 24.2% and ulcer-like projection was 27.7%. The present study concluded that thrombosed type is not rare in acute aortic dissection and contrast-enhanced CT as well as pre-contrast CT, is of great value in diagnosing thrombosed type. 'Hyperdense crescent sign' in pre-contrast CT is characteristic of intramural hematoma. (author)

  7. Anesthesia Approach in Endovascular Aortic Reconstruction

    Directory of Open Access Journals (Sweden)

    Ayşin Alagöl

    2013-03-01

    Full Text Available Introduction: We have analyzed our initial results of our anesthesia techniques in our new-onset endovascular aortic reconstruction cases.Patients and Methods: The perioperative data of 15 elective and emergent endovascular aortic reconstruction cases that were operated in 2010-2011 were collected in a database. The choice of anesthesia was made by the risk factors, surgical team’s preferences, type and location of the aortic pathology and by the predicted operation duration. The data of local and general anesthesia cases were compared.Results: Thirteen (86.7% cases were male and 2 (13.3% female. Eleven patients were in ASA Class III. The demographic parameters, ASA classifications, concurrent diseases were similar in both groups. Thirteen (86.7% cases had infrarenal abdominal aortic aneurysm and 2 (13.3% had Type III aortic dissection. The diastolic arterial pressures were lower in general anesthesia group in 20th and 40th minutes’ measurements just like the mean arterial pressure measurements at the 40th, 100th minutes and during the deployment of the graft. Postoperative mortality occurred in 3 (20.0% patients and they all had general anesthesia and they were operated on emergency basis. Postoperative morbidity occurred in four patients that had general anesthesia (acute renal failure, multi-organ failure and pneumonia. The other patient had atrial fibrillation on the 1st postoperative day and was converted to sinus rhythm with amiodarone infusion.Conclusion: Edovascular aortic reconstruction procedures can safely be performed with both general and local anesthesia less invasively compared to open surgery. General anesthesia may be preferred for the better hemodynamic control.

  8. Alterations in vascular function in primary aldosteronism: a cardiovascular magnetic resonance imaging study

    OpenAIRE

    Mark, P. B.; Boyle, S; Zimmerli, L U; McQuarrie, E.P.; Delles, C.; Freel, E. M.

    2014-01-01

    Introduction: Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV). Methods: We studied PA (n=14)...

  9. Idiopathic thoracic aortic aneurysm at pediatric age.

    Science.gov (United States)

    Marín-Manzano, E; González-de-Olano, D; Haurie-Girelli, J; Herráiz-Sarachaga, J I; Bermúdez-Cañete, R; Tamariz-Martel, A; Cuesta-Gimeno, C; Pérez-de-León, J

    2009-03-01

    A 6-year-old-boy presented with epigastric pain and vomiting over 1 year. Chest X-ray and esophagogastric transit showed a mediastinal mass. A chest computerized tomography angiogram demonstrated a descending thoracic aortic aneurysm. Analytical determinations carried out were all negative. The aneurysm was surgically repaired using a Dacron patch. The anatomopathological study described atherosclerotic lesions with calcifications, compatible with an atherosclerotic aneurysm wall. Aneurysms are uncommon in the pediatric population. Usually, no pathogenesis can be determined, and thus, such cases are grouped as idiopathic. Direct repair with or without patch is a therapeutic alternative in pediatric aneurysms and can allow the growth of the aortic circumference.

  10. Chylous complications after abdominal aortic surgery.

    Science.gov (United States)

    Haug, E S; Saether, O D; Odegaard, A; Johnsen, G; Myhre, H O

    1998-12-01

    Two patients developed chylous complications following abdominal aortic aneurysm repair. One patient had chylous ascitis and was successfully treated by a peritoneo-caval shunt. The other patient developed a lymph cyst, which gradually resorbed after puncture. Chylous complications following aortic surgery are rare. Patients in bad a general condition should be treated by initial paracentesis and total parenteral nutrition, supplemented by medium-chain triglyceride and low-fat diet. If no improvement is observed on this regimen, the next step should be implementation of a peritoneo-venous shunt, whereas direct ligation of the leak should be reserved for those who are not responding to this treatment. PMID:10204656

  11. Infective endocarditis following transcatheter aortic valve replacement-

    DEFF Research Database (Denmark)

    Loh, Poay Huan; Bundgaard, Henning; S�ndergaard, Lars

    2013-01-01

    Transcatheter aortic valve replacement (TAVR) can improve the symptoms and prognosis of patients with severe aortic stenosis who, due to a high expected operative risk, would not have otherwise been treated surgically. If these patients develop prosthetic valve endocarditis, their presentations may...... be atypical causing a delay in the diagnosis and treatment. The management is also complicated by their comorbidities, and surgical treatment may not be feasible leading to a significant morbidity and mortality. We describe a case of an 85-year-old man with TAVI prosthetic valve endocarditis successfully...

  12. Contemporary management of blunt aortic trauma.

    Science.gov (United States)

    Dubose, J J; Azizzadeh, A; Estrera, A L; Safi, H J

    2015-10-01

    Blunt thoracic aortic injury (BTAI) remains a common cause of death following blunt mechanisms of trauma. Among patients who survive to reach hospital care, significant advances in diagnosis and treatment afford previously unattainable survival. The Society for Vascular Surgery (SVS) guidelines provide current best-evidence suggestions for treatment of BTAI. However, several key areas of controversy regarding optimal BTAI care remain. These include the refinement of selection criteria, timing for treatment and the need for long-term follow-up data. In addition, the advent of the Aortic Trauma Foundation (ATF) represents an important development in collaborative research in this field. PMID:25868973

  13. Aortic valve replacement in octogenarians

    Directory of Open Access Journals (Sweden)

    Dark John H

    2007-07-01

    Full Text Available Abstract Background and Aims As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR in octogenarians. Methods 68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37 underwent isolated AVR whilst 46% (31 underwent combined AVR and CABG. Results Follow up was 100% complete. The mean age was 83.1 ± s.d. 2.9 years, a mean gradient of 83 ± s.d. 31 mmHg and mean AVA of 0.56 cm2. The mean additive EuroSCORE was 8.6 ± s.d. 1.2, the logistic EuroSCORE mean 12.0 ± s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p Conclusion Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.

  14. Input Devices to Support Communication for People with Serious Disability

    OpenAIRE

    Zhang, Chao; Kumano, Shinichi; Takashima, Kenichi; Tanaka, Motohiro; Moromugi, Shunji; Ishimatsu,Takakazu

    2013-01-01

    Persons suffering from intractable disease like ALS (Amyotrophic Lateral Sclerosis) and spinal cord injury often show deterioration in muscular function. Some of these patients are obliged to use artificial respirators and cannot have verbal communication with others. In order to support their communication, there exist various input devices like touch sensor input devices, capacitance sensor input devices and also vision input devices. In addition, computer controlled environment is helpful ...

  15. Treatment of infrarenal abdominal aortic dissection concomitant with an aneurysm

    Institute of Scientific and Technical Information of China (English)

    WANG Li-xin; ZHU Ting; FU Wei-guo; WANG Yu-qi; XI Xun; GUO Da-qiao; CHEN Bin; JIANG Jun-hao; YANG Ju; SHI Zhen-yu

    2007-01-01

    @@ Aortic dissection occurs when layers of the aortic walls are separated by the blood flow through an intimal tear. Dissection of the aorta most frequently originates in the ascending aorta (70%), followed by the descending aorta (22%), the aortic arch (7%) and the abdominal aorta (1/%).1 The dissection limited to the abdominal aorta is rare.2 An isolated abdominal aortic dissection (IAAD) concomitant with an abdominal aortic aneurysm (AAA) is uncommon. We present here one patient with IAAD and AAA treated by endovascular therapy.

  16. Infected abdominal aortic aneurysm due to Morganella morganii: CT findings.

    Science.gov (United States)

    Kwon, Oh Young; Lee, Jong Seok; Choi, Han Sung; Hong, Hoon Pyo; Ko, Young Gwan

    2011-02-01

    An infected aortic aneurysm, or mycotic aneurysm, is a rare arterial dilatation due to destruction of the infected vessel wall. Common pathogens resulting in an infected aortic aneurysm are Salmonella and Clostridium species, as well as Staphylococcus aureus; Morganella morganii, on the other hand, is very rare. An infected abdominal aortic aneurysm has tendencies to grow rapidly and to rupture. The mortality rate is high in patients undergoing emergent surgical intervention. We report the case of a 65-year-old man who presented with an infected abdominal aortic aneurysm caused by M. morganii. A high index of suspicion and imaging tests are necessary in order to diagnose an infected aortic aneurysm.

  17. Input Sub-System in Linux%Linux 下的 Input 子系统

    Institute of Scientific and Technical Information of China (English)

    朱银瑞; 吴庆洪; 吴华玲

    2013-01-01

    In Linux system the Input sub-system is character driven system. Now android, X-windows, Qt, and many other applications in Linux system for input devices such as keyboard, mouse, touch screen support all through, or more and more inclined to standard Input subsystem. Based on current conditions, this article first from Input_dev layer, Input Core layer and the Event Handler layer introduced the implementation of Input sub-system framework, and then achieve it through the Input sub-system for 4x4 matrix keypad and the user in the application layer use the interface function provided by Input sub-system to operate the buttons in order to view the specific states and values of keys. The results shows that the keypad driver in Input sub-system are more stable and have a high efficiency and so it has a good common use.%Input 子系统属于 Linux 系统下字符类驱动系统,现在 Android、X-windows、Qt 等众多应用于 Linux 系统中键盘、鼠标、触摸屏等输入设备的支持都通过、或越来越多倾向于标准的 Input 子系统。基于现况本文首先从 Input_dev 层, Input Core 层和 Event Handler 层介绍 Input 输入子系统的实现框架,然后通过4x4矩阵按键在Input 子系统中的实现以及用户在应用层通过 Input 子系统提供的接口函数对按键操作来查看具体的键值和按键状态。测试结果表明, Input 子系统里的按键驱动稳定高效通用性强。

  18. Congenital quadricuspid aortic valve: analysis of 11 surgical cases

    Institute of Scientific and Technical Information of China (English)

    TANG Yang-feng; XU Ji-bin; HAN Lin; LU Fang-lin; LANG Xi-long; SONG Zhi-gang; XU Zhi-yun

    2011-01-01

    Background Congenital quadricuspid aortic valve is rarely seen during aortic valve replacement (AVR).The diagnosis and treatment of the disease were reported in 11 cases.Methods Eleven patients (nine men and two women,mean age 33.4 years) with quadricuspid aortic valve were retrospectively evaluated.Medical records,echocardiograms and surgical treatment were reviewed.Results In accordance with the Hurwitz and Roberts classification,the patients were classified as type A (n=2),type B (n=7),type F (n=1) and type G (n=1).Three patients were associated with other heart diseases,including infective endocarditis and mitral prolaps,left superior vena cava,aortic aneurysm.All had aortic regurgitation (AR) except two with aortic stenosis (AS),detected by color-flow Doppler echocardiography.The congenital quadricuspid aortic valve deformity in seven patients was diagnosed by echocardiography.All patients underwent successful aortic valve replacement.Conclusion Quadricuspid aortic valve is a rare cause of aortic insufficiency,while echocardiography plays an important role in diagnosing the disease.Aortic valve replacement is the major therapy for the disease.

  19. Aortic root, not valve, calcification correlates with coronary artery calcification in patients with severe aortic stenosis

    DEFF Research Database (Denmark)

    Henein, Michael; Hällgren, Peter; Holmgren, Anders;

    2015-01-01

    BACKGROUND: The underlying pathology in aortic stenosis (AS) and coronary artery stenosis (CAS) is similar including atherosclerosis and calcification. We hypothesize that coronary artery calcification (CAC) is likely to correlate with aortic root calcification (ARC) rather than with aortic valve...... calcification (AVC), due to tissue similarity between the two types of vessel rather than with the valve leaflet tissue. MATERIAL AND METHODS: We studied 212 consecutive patients (age 72.5 ± 7.9 years, 91 females) with AS requiring aortic valve replacement (AVR) in two Heart Centers, who underwent multidetector...... even after adjusting for age (p = 0.01). AVC score was associated with BAV after adjusting for age (p = 0.03) but ARC was not. Of the total cohort, 82 patients (39%) had significant coronary stenosis (>50%), but these were not different in the pattern of calcification from those without CAS. CAC...

  20. Computed tomography angiography of hybrid thoracic endovascular aortic repair of the aortic arch.

    Science.gov (United States)

    Akhtar, Nila J; Oderich, Gustavo S; Vrtiska, Terri J; Williamson, Eric E; Araoz, Philip A

    2013-05-01

    Endovascular repair of the aorta has traditionally been limited to the abdominal aorta and, more recently, the descending thoracic aorta. However, recently hybrid repairs (a combination of open surgical and endovascular repair) have made endovascular repair of the aortic arch possible. Hybrid repair of the aortic arch typically involves an open surgical debranching procedure that allows for revascularization of the aortic arch vessels and subsequent endovascular stent placement. These approaches avoid the deep hypothermic circulatory arrest required for full, open surgical repair of the aortic arch. In hybrid repairs, the stent landing zone determines which branch vessels will be covered and therefore need revascularization. This article will review the preprocedure assessment with computed tomography angiography, techniques for revascularization and postprocedure complications. PMID:23621141

  1. Cardiovascular magnetic resonance of quinticuspid aortic valve with aortic regurgitation and dilated ascending aorta

    OpenAIRE

    Zhang Zhaoqi; Zhang Lijun; Meng Yanfeng; Wang Yongmei; Yang Xiaoming

    2009-01-01

    Abstract We report a rare case of a quinticuspid aortic valve associated with regurgitation and dilation of the ascending aorta, which was diagnosed and post-surgically followed up by cardiovascular magnetic resonance and dual source computed tomography.

  2. Factors influencing long-term survival after aortic valve replacement.

    Directory of Open Access Journals (Sweden)

    Shigenobu,Masaharu

    1980-06-01

    Full Text Available In the aortic stenosis group, the left ventricular (LV muscle mass index was a good parameter for predicting the prognosis. Associated mitral valve disease had no influence on long term survival after aortic valve replacement. In the aortic insufficiency group, associated mitral valve disease had a marked influence on the results of aortic valve replacement. In general, the aortic insufficiency group had less clinical improvement postoperatively than the aortic stenosis group. In the annuloaortic ectasia group, left ventricular enddiastolic pressure (LVEDP might be the predictor to the prognosis. This group had the worst prognosis, of the three groups. Early operation should be considered for patients who have no, or only mild symptoms of, aortic valve disease.

  3. A rare case of aortic sinuses of valsalva fistula to multiple cardiac chambers secondary to periannular aortic abscess formation from underlying Brucella endocarditis

    Directory of Open Access Journals (Sweden)

    Sabzi, Feridoun

    2015-11-01

    Full Text Available The concomitant presence of abnormal connection from three aortic valsalva sinuses to cardiac chambers is a rare complication of native aortic endocarditis. This case report presents a 37-year-old Iranian female patient who had native aortic valve endocarditis complicated by periannular abscess formation and subsequent perforation to multi-cardiac chambers associated with congestive heart failure and left bundle branch block. Multiple aorto-cavitary fistulas to right atrium, main pulmonary artery, and formation of a pocket over left atrial roof were detected by transthoracic echocardiogram (TTE. She had received a full course of antibiotics therapy in a local hospital and was referred to our center for further surgery. TTE not only detected multiple aorto-cavitary fistulas but also revealed large vegetation in aortic and mitral valve leaflets and also small vegetation in the entrance of fistula to right atrium. However, the tricuspid valve was not involved in infective endocarditis. She underwent open cardiac surgery with double valve replacement with biologic valves and reconstruction of left sinus of valsalva fistula to supra left atrial pocket by pericardial patch repair. The two other fistulas to main pulmonary artery and right atrium were closed via related chambers. The post-operative course was complicated by renal failure and prolonged dependency to ventilator that was managed accordingly with peritoneal dialysis and tracheostomy. The patient was discharged on the 25 day after admission in relatively good condition. The TTE follow-up one year after discharge revealed mild paravalvular leakage in aortic valve position, but the function of mitral valve was normal and no residual fistulas were detected.

  4. A rare case of aortic sinuses of valsalva fistula to multiple cardiac chambers secondary to periannular aortic abscess formation from underlying Brucella endocarditis.

    Science.gov (United States)

    Sabzi, Feridoun; Heidari, Aghighe; Faraji, Reza

    2015-01-01

    The concomitant presence of abnormal connection from three aortic valsalva sinuses to cardiac chambers is a rare complication of native aortic Brucella endocarditis. This case report presents a 37-year-old Iranian female patient who had native aortic valve Brucella endocarditis complicated by periannular abscess formation and subsequent perforation to multi-cardiac chambers associated with congestive heart failure and left bundle branch block. Multiple aorto-cavitary fistulas to right atrium, main pulmonary artery, and formation of a pocket over left atrial roof were detected by transthoracic echocardiogram (TTE). She had received a full course of antibiotics therapy in a local hospital and was referred to our center for further surgery. TTE not only detected multiple aorto-cavitary fistulas but also revealed large vegetation in aortic and mitral valve leaflets and also small vegetation in the entrance of fistula to right atrium. However, the tricuspid valve was not involved in infective endocarditis. She underwent open cardiac surgery with double valve replacement with biologic valves and reconstruction of left sinus of valsalva fistula to supra left atrial pocket by pericardial patch repair. The two other fistulas to main pulmonary artery and right atrium were closed via related chambers. The post-operative course was complicated by renal failure and prolonged dependency to ventilator that was managed accordingly with peritoneal dialysis and tracheostomy. The patient was discharged on the 25(th) day after admission in relatively good condition. The TTE follow-up one year after discharge revealed mild paravalvular leakage in aortic valve position, but the function of mitral valve was normal and no residual fistulas were detected. PMID:26605134

  5. Cross Talk between NOTCH Signaling and Biomechanics in Human Aortic Valve Disease Pathogenesis

    Directory of Open Access Journals (Sweden)

    Richard C. Godby

    2014-12-01

    Full Text Available Aortic valve disease is a burgeoning public health problem associated with significant mortality. Loss of function mutations in NOTCH1 cause bicuspid aortic valve (BAV and calcific aortic valve disease. Because calcific nodules manifest on the fibrosa side of the cusp in low fluidic oscillatory shear stress (OSS, elucidating pathogenesis requires approaches that consider both molecular and mechanical factors. Therefore, we examined the relationship between NOTCH loss of function (LOF and biomechanical indices in healthy and diseased human aortic valve interstitial cells (AVICs. An orbital shaker system was used to apply cyclic OSS, which mimics the cardiac cycle and hemodynamics experienced by AVICs in vivo. NOTCH LOF blocked OSS-induced cell alignment in human umbilical vein endothelial cells (HUVECs, whereas AVICs did not align when subjected to OSS under any conditions. In healthy AVICs, OSS resulted in decreased elastin (ELN and α-SMA (ACTA2. NOTCH LOF was associated with similar changes, but in diseased AVICs, NOTCH LOF combined with OSS was associated with increased α-SMA expression. Interestingly, AVICs showed relatively higher expression of NOTCH2 compared to NOTCH1. Biomechanical interactions between endothelial and interstitial cells involve complex NOTCH signaling that contributes to matrix homeostasis in health and disorganization in disease.

  6. Marfan syndrome in children and adolescents: predictive and prognostic value of aortic root growth for screening for aortic complications

    OpenAIRE

    Groenink, M; Rozendaal, L; Naeff, M.S.J.; Hennekam, R.C.M.; Hart, A.A.M.; Wall; Mulder, B.J.M.

    1998-01-01

    Objective—To assess and measure the diagnostic and prognostic value of individual aortic root growth in children and adolescents with Marfan syndrome.
Design—From 1983 to 1996, 250 children were screened for Marfan syndrome. Serial echocardiographic aortic root measurements of 123 children (57 Marfan, 66 control) were available for evaluation of aortic root growth. Aortic root diameters were correlated with body surface area. Based on individual growth of the aortic root a discrimination form...

  7. The ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography

    OpenAIRE

    Liu, Ying; Xu, Jian; Jian LI; Ren, Jing; LIU, HONGTAO; Xu, Junqing; Wei, Mengqi; Hao, Yuewen; Zheng, Minwen

    2013-01-01

    Background Aortic dissection is a lift-threatening medical emergency associated with high rates of morbidity and mortality. The incidence rate of aortic dissection is estimated at 5 to 30 per 1 million people per year. The prompt and correct diagnosis of aortic dissection is critical. This study was to compare the ascending aortic image quality and the whole aortic radiation dose of high-pitch dual-source CT angiography and conventional dual-source CT angiography. Methods A total of 110 conse...

  8. Anatomics Knowledges of Aortic Root in the Transcatheter Aortic Valve Implantation.

    Directory of Open Access Journals (Sweden)

    Marcelo Cerezo

    2010-12-01

    Full Text Available The Aortic Valve is a valvular system that bears different high pressure forces. It takes part of a complex structure called Aortic Root. Nowadays, anatomic knowledge has taken a preponderant role, due to the use of the Transcatether Aortic Valve Implant (TAVI. To describe the patient´s characteristics which exclude them of the TAVI for anatomic reasons in cadaveric dissections and transthoracic echocardiograms. A descriptive retrospective analysis of 67 individuals was performed and divided into two groups. Group A: Formalized cadaveric dissections with hypertrofic hearts and aortic sclerosis signs from the Chair A of Anatomy of the University of La Plata (UNLP. Group B: Transthoracic Echocardiograms realized at the San Martín Hospital of La Plata between January 2005 and December 2009. Out of 67 individuals assessed, 17 (25% had one or more contraindications for TAVI. Five on Group A (36%, and 12 on Group B (23%. The most common anatomic contraindication was the Ascending Aortic diameter less than 30mm and the aortic annulus less than 20mm, following to the RAo-TSVI Angle more than 145° (2 to Group A, and 4 to Group B and the Septal thickness more than 17mm (no one to Group A, and 3 to Group B. Only just one individual was found with a low implant left coronary artery in the Group A avoiding TAVI. According to this study, the anatomic contraindications to realize TAVI are frequent due to the diagnosis devices available at the moment. The anatomic aortic root knowledge and the aortic valve interindividual variability will allow the improvement of the manufactured devices made in the market.

  9. Surgical Treatment of Aortic Aneurysm and Aortic Dissection:A Retrospective Analysis of 122 Cases

    Institute of Scientific and Technical Information of China (English)

    Tucheng SUN; Xionggang JIANG; Kailun ZHANG; Jie CAI; Shu CHEN; NYANGASSA B J; Zongquan SUN

    2009-01-01

    The study summarizes the clinical experience of surgical treatments of various types of thoracic aneurysm and aortic dissection.Clinical data of 122 patients with thoracic aneurysm and aortic dissection during July 2005 to July 2008 were retrospectively analyzed.The elective operations were performed in 107 patients while emergency surgery was done in 15 cases.Different surgical strategies were employed on the basis of diseased region,including simple ascending aortic replacement (n=3),aortic root replacement (n=43),hemi-arch replacement/total arch replacement + elephant trunk technique (n=32),thoracic/thoracoabdominal aortic replacement (n=8) and endovascular repair (n=36).In this series,there is 4 cases of perioperative death due to massive cerebral hemorrhage (n=1),respiratory failure (n=1) and multiple organ dysfunction syndrome (MODS) (n=2).Three cases developed post-operative massive cerebral infarction and the relatives of the patients abandoned treatment.Instant success rate of endovascular repair was 100%.The intimal rupture was sealed.Blood flow was unobstructed in true lumen and no false lumen was visualized.It was concluded that aggressive surgery should be considered in the patients with thoracic aneurysm and aortic dissection.Surgical procedures should vary with the location and the nature of the lesions.

  10. Medtronic Freestyle Aortic Root Bioprosthesis Implantation for the Infective Endocarditis on Aortic Root

    Directory of Open Access Journals (Sweden)

    Zekeriya Arslan

    2013-10-01

    Full Text Available    Infective endocarditis and periannular abscess formation are serious problems in cardiac valve surgery, requiring extensive surgical debridement and reconstruction of the aortic annulus. We aimed to report two cases which were successfully treated with bioprosthetic valve implantation for infective endocarditis. Transosephageal echocardiography were performed for the diagnosis of one prosthetic and one native destructive aortic valve endocarditis in association with congestive heart failure (NYHA class-VI and abscess formation. Medtronic Freestyle stentless aortic root bioprosthesis was implanted into the left ventricular outflow tract after surgical radical aortic root debridement for each patient followed with medical treatment, which was extended to six weeks. Neither early nor late mortality was detected. One patient required prolonged ventilatory support (two days and permanent DDD-R pacing. Echocardiography showed no signs of valve dysfunction or recurrent endocarditis for both patients in 10 months follow up.Medtronic Freestyle stentless aortic root bioprosthesis may be a good alternative way of treatment to aortic valve and root endocarditis instead of homograft.

  11. Aorto-right atrial fistula after ascending aortic replacement or aortic value replacement

    International Nuclear Information System (INIS)

    Objective: To evaluate the CT features of aorto-right atrial fistula after aortic valve replacement (AVR) or ascending aortic replacement. Methods: Eighty-seven patients with aortic-right atrial fistula underwent CT after operation. The CT features were retrospectively analyzed. Fistula was measured according to maximum width of the shunt. Results: Aorto-right atrial fistula was detected in 87 patients after aortic valve replacement or ascending aortic replacement by CT scan. Among them, 25 patients were diagnosed as mild aorto-right atrial fistula, 47 patients as moderate, and 15 patients as severe. Thirty-seven patients underwent follow-up CT.Among them, 10 patients with mild to moderate aorto-right atrial fistula were considered to have complete regression, 8 patients with mild aorto-right atrial fistula considered to have incomplete regression, 14 patients with mild to moderate aorto-right atrial fistula considered to have stable condition, and 5 patients with moderate aorto-right atrial fistula considered to have progression at the 3-month follow-up. Conclusion: CT is a useful tool for defining aorto-right atrial fistula after AVR or ascending aortic replacement and for evaluating it in follow-up. (authors)

  12. Endovascular resection of the native aortic valve before transcatheter aortic valve implantation: state of the art and review.

    Science.gov (United States)

    Navarra, Emiliano; Mosala Nezhad, Zahra; Bollen, Xavier; Gielen, Charles-Edouard; Mastrobuoni, Stefano; De Kerchove, Laurent; Raucent, Benoit; Astarci, Parla

    2016-09-01

    Transcatheter aortic valve implantation was introduced into clinical practice in 2002 as a rescue approach in patients presenting with symptomatic severe aortic stenosis but not eligible for conventional aortic valve replacement. This technique allows implantation of a balloon expandable bioprosthesis without resection of the native aortic valve. Several complications are described as a consequence of the residual highly calcified valve being squeezed against the aortic wall by the stent of the implant. This can result in deformation of the metal stent and paravalvular leakage, risk of occlusion of the coronary ostia, or central and peripheral embolization of valvular debris. To avoid these complications, many authors suggest the possibility to resect and remove the native aortic valve before transcatheter aortic valve implantation. In this field, different authors have described possible techniques and different sources of energy to resect the calcified valve. In this article, we review the development of these experimental techniques and discuss future prospects in this field. PMID:27032472

  13. Endovascular aortic repair: First twenty years

    Directory of Open Access Journals (Sweden)

    Končar Igor

    2012-01-01

    Full Text Available Endovascular aortic/aneurysm repair (EVAR was introduced into clinical practice at the beginning of the nineties. Its fast development had a great influence on clinicians, vascular surgeons and interventional radiologists, educational curriculums, patients, industry and medical insurance. The aim of this paper is to present the contribution of clinicians and industry to the development and advancement of endovascular aortic repair over the last 20 years. This review article presents the development of EVAR by focusing on the contribution of physicians, surgeons and interventional radiologists in the creation of the new field of vascular surgery termed hybrid vascular surgery, and also the contribution of technological advancement by a significant help of industrial representatives – engineers and their counselors. This article also analyzes studies conducted in order to compare the successfulness of EVAR with up-to-now applied open surgical repair of aortic aneurysms, and some treatment techniques of other aortic diseases. During the first two decades of its development the EVAR method was rapidly progressing and was adopted concurrently with the expansion of technology. Owing to large randomized studies, early and long-term results indicate specific complications of this method, thus influencing further technological improvement and defining risk patients groups in whom the use of the technique should be avoided. Good results are insured only in centers, specialized in vascular surgery, which have on their disposal adequate conditions for solving all complications associated with this method.

  14. [Albert Einstein and his abdominal aortic aneurysm].

    Science.gov (United States)

    Cervantes Castro, Jorge

    2011-01-01

    The interesting case of Albert Einstein's abdominal aortic aneurysm is presented. He was operated on at age 69 and, finding that the large aneurysm could not be removed, the surgeon elected to wrap it with cellophane to prevent its growth. However, seven years later the aneurysm ruptured and caused the death of the famous scientist.

  15. The future of transcatheter aortic valve implantation.

    Science.gov (United States)

    Hamm, Christian W; Arsalan, Mani; Mack, Michael J

    2016-03-01

    Since the introduction of transcatheter aortic valve implantation (TAVI) into clinical practice, the treatment of aortic stenosis has changed dramatically. In the past, medical therapy with or without balloon aortic valvuloplasty was the only option for inoperable patients. More recently, TAVI has become the treatment of choice for these patients and the preferred alternative for high-risk operable patients. Surgical aortic valve replacement (SAVR) currently remains the gold standard for patients at low or intermediate operative risk. As randomized trials have demonstrated comparable results between TAVI and SAVR in the high-risk population, there is now a clear trend towards performing TAVI even in intermediate-risk patients while awaiting the results of randomized trials in that population. Nevertheless, there are still questions regarding TAVI involving paravalvular leak (PVL), stroke, pacemaker requirements, and durability that remain to be more definitively answered before TAVI can routinely be performed in a broader, lower risk population. Improvements in patient selection, imaging, and second and third generation devices have decreased the incidence of PVLs and vascular complications that followed the earliest TAVI procedures, but the rates of perioperative stroke and permanent pacemaker implantation must still be addressed. Furthermore, the long-term durability of TAVI devices and a role for post-procedure antithrombotic management remain unanswered. Until these questions are more clearly answered, it is the Heart Team's task to determine the optimal treatment for each patient based on risk scores, frailty metrics, comorbidities, patient preference, and potential for improvement in quality of life.

  16. Endovascular treatment of thoracic aortic diseases

    Directory of Open Access Journals (Sweden)

    Davidović Lazar

    2013-01-01

    Full Text Available Bacground/Aim. Endovascular treatment of thoracic aortic diseases is an adequate alternative to open surgery. This method was firstly performed in Serbia in 2004, while routine usage started in 2007. Aim of this study was to analyse initial experience in endovacular treatment of thoracic aortic diseses of three main vascular hospitals in Belgrade - Clinic for Vascular and Endovascular Surgery of the Clinical Center of Serbia, Clinic for Vascular Surgery of the Military Medical Academy, and Clinic for Vascular Surgery of the Institute for Cardiovascular Diseases “Dedinje”. Methods. Between March 2004. and November 2010. 41 patients were treated in these three hospitals due to different diseases of the thoracic aorta. A total of 21 patients had degenerative atherosclerotic aneurysm, 6 patients had penetrating aortic ulcer, 6 had posttraumatic aneurysm, 4 patients had ruptured thoracic aortic aneurysm, 1 had false anastomotic aneurysm after open repair, and 3 patients had dissected thoracic aneurysm of the thoracoabdominal aorta. In 15 cases the endovascular procedure was performed as a part of the hybrid procedure, after carotidsubclavian bypass in 4 patients and subclavian artery transposition in 1 patient due to the short aneurysmatic neck; in 2 patients iliac conduit was used due to hypoplastic or stenotic iliac artery; in 5 patients previous reconstruction of abdominal aorta was performed; in 1 patient complete debranching of the aortic arch, and in 2 patients visceral abdominal debranching were performed. Results. The intrahospital mortality rate (30 days was 7.26% (3 patients with ruptured thoracic aneurysms died. Endoleak type II in the first control exam was revealed in 3 patients (7. 26%. The patients were followed up in a period of 1-72 months, on average 29 months. The most devastating complication during a followup period was aortoesofageal fistula in 1 patient a year after the treatment of posttraumatic aneurysm. Conversion was

  17. Nursing cooperation in endovascular aneurysm repair treatment for aortic dissection

    International Nuclear Information System (INIS)

    Objective: To summarize the main points of nursing cooperation in endovascular aneurysm repair treatment for aortic dissection. Methods: Preoperative psychological care and the other preparations were carefully conducted. During the operation, the patient's body was correctly placed. Active cooperation with the performance of angiography and close observation during heparinization were carried out. The proper delivery of catheter and stent to the operator was carefully done. Close observation for the patient's vital signs, the renal function and the changes of limb blood supply were made. Results: Under close cooperation of' the operators, nurses, anesthesiologists and technicians, the surgery was successfully accomplished in 35 patients. The monitoring of vital signs during the entire performance of operation was well executed. No surgical instruments delivery error's or surgery failure due to unsuitable cooperation occurred. Conclusion: Perfect preoperative preparation, strict nursing cooperation and team cooperation are the key points to ensure a successful endovascular aneurysm repair for aortic dissection. (authors)

  18. Reconstructive surgery of the aortic valve

    Directory of Open Access Journals (Sweden)

    Mendonça José Teles de

    2003-01-01

    Full Text Available OBJECTIVE: Lacking an ideal valve substitute and motivated by the good results of mitral valve repair since 1990, we faced with determination aortic valve reconstruction surgery. The objective of this paper is to show our experience with this procedure. METHOD: Between January of 1990 and December of 2001; 136 aortic valve repair surgeries were performed. Seventy-five (55.1% of the patients were female and the ages ranged from 4 to 70 years (mean 23.3 ± 1.2 years. Every patient had rheumatic valve disease and insufficiency was the most prevalent type (108 patients - 79.4%, followed by double aortic lesion in 16 (11.7% patients and stenosis in 12 (8.8%. The surgical techniques used were: subcommissural annuloplasty in 74 (54.4% patients, commissurotomy in 38 (27.9%, cusp extension with pericardium in 17 (12.5%, substitution of one cusp in 2 (1.4%, cusp suspension by annuloplasty in 37 (27.2% and Valsalva sinus remodeling in 27 (19.8%. The surgery exclusively involved the aortic valve in 57 (41.9% patients and was associated in 79 (mitral valve replacement in 12, mitral repair in 65, coronary artery bypass grafting in 1 and pulmonary commissurotomy in 1. RESULTS: Hospital mortality was 2.2% and 22 (16.2% patients underwent a new surgery during the follow-up period (57.7 ± 3.5 months. CONCLUSIONS: Aortic valve repair is a safe surgical procedure that can be used in an increasing number of patients with promising results.

  19. Limitation of imaging in identifying iatrogenic aortic coarctation following thoracic endovascular aortic repair.

    Science.gov (United States)

    Thakkar, Rajiv N; Thomaier, Lauren; Qazi, Umair; Verde, Franco; Malas, Mahmoud B

    2015-04-01

    A 21-year-old male suffered blunt trauma from a motor vehicle accident causing thoracic aorta tear. The smallest available stent graft was deployed. Definitive repair was later performed using a 22 × 22 × 116 mm Talent Thoracic Stent Graft. The postoperative course was uneventful. Seventeen months later, he presented with dizziness, chest pain, acute renal failure, malignant hypertension, and troponin elevation. Computed tomography (CT) angiogram and transesophageal echocardiogram did not reveal any dissection, stent stenosis or collapse. Cardiac catheterization showed normal coronary arteries but a 117 mm Hg gradient across the stent graft. Iatrogenic coarctation of the aorta was confirmed with a second measurement during arch angiogram. A Palmaz stent was deployed over the distal end of the previous stent graft with complete resolution of symptoms and gradual normalization of kidney function. This case report demonstrates a need for wider availability and selecting appropriate stent graft in treating traumatic aortic injuries in young patients. It is the first case report of the inability of current imaging modalities in confirming stent collapse. Pressure gradient is a useful tool in confirming stent collapse when clinical scenario does not match CT findings.

  20. 参麦注射液对主动脉夹层腔内隔绝手术患者呼吸功能影响的临床观察%Clinical observation of the effect of Shenmai injecti on on the respiratory function in patients with aortic dissection after endovascular exclusion

    Institute of Scientific and Technical Information of China (English)

    李潮杰; 余瑜; 陈杰

    2015-01-01

    目的:观察参麦注射液治疗主动脉夹层腔内隔绝手术患者的临床疗效及不良反应情况。方法:43例患者随机分成对照组22例,采用常规西医治疗;观察组21例在常规治疗基础上加用参麦注射液治疗。分别测定术前(T0)、术后30分钟(T1)、术后24小时(T2)、术后72小时(T3)氧合指数并两组进行比较,观察两组辅助通气时间及不良反应。结果:治疗后观察组氧合指数高于对照组,辅助通气时间少于对照组,差异有统计学意义(P<0.05)。结论:应用参麦注射液治疗B型主动脉夹层腔内隔绝术后患者,对改善患者术后早期呼吸功能、促进康复起到有益的作用。%Objective:To evaluate the clinical effect of Shenmai injection on the respiratory function in patients with aortic dissection after endovascular exclusion by using randomized controlled study method . Methods: The 43 patients were randomly divided into the control group(22 cases) treated with routine western theraphy, and the observation group(21 cases) with treated routine western theraphy combined with Shenmai injection. The oxygenation index was measured respectively in T0 (before operation), T1 (30 minutes after operation), T2 (24 hours after operation), and T3 (72 hours after operation), duration of assisted ventilation and adverse reactions also observed in two groups. Results:The oxygenation index in the observation group was higher than that in the control group , and the duration of assisted ventilation was less than that in the control group , and the difference was statistically significant (P<0.05). Conclusion:The application of the Shenmai injection in the treatment of patients with B type aortic dissection after endovascular exclusion has a beneficial effect on improving the early respiratory function and promoting recovery after operation .

  1. Serial Input Output

    Energy Technology Data Exchange (ETDEWEB)

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  2. SDR Input Power Estimation Algorithms

    Science.gov (United States)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  3. Framework for Modelling Multiple Input Complex Aggregations for Interactive Installations

    DEFF Research Database (Denmark)

    Padfield, Nicolas; Andreasen, Troels

    2012-01-01

    on fuzzy logic and provides a method for variably balancing interaction and user input with the intention of the artist or director. An experimental design is presented, demonstrating an intuitive interface for parametric modelling of a complex aggregation function. The aggregation function unifies...... hierarchical, importance-weighted and ordered-weighted fuzzy averaging to provide complex combinations of user input....

  4. Estimated aortic stiffness is independently associated with cardiac baroreflex sensitivity in humans: role of ageing and habitual endurance exercise.

    Science.gov (United States)

    Pierce, G L; Harris, S A; Seals, D R; Casey, D P; Barlow, P B; Stauss, H M

    2016-09-01

    We hypothesised that differences in cardiac baroreflex sensitivity (BRS) would be independently associated with aortic stiffness and augmentation index (AI), clinical biomarkers of cardiovascular disease risk, among young sedentary and middle-aged/older sedentary and endurance-trained adults. A total of 36 healthy middle-aged/older (age 55-76 years, n=22 sedentary and n=14 endurance-trained) and 5 young sedentary (age 18-31 years) adults were included in a cross-sectional study. A subset of the middle-aged/older sedentary adults (n=12) completed an 8-week-aerobic exercise intervention. Invasive brachial artery blood pressure waveforms were used to compute spontaneous cardiac BRS (via sequence technique), estimated aortic pulse wave velocity (PWV) and AI (AI, via brachial-aortic transfer function and wave separation analysis). In the cross-sectional study, cardiac BRS was 71% lower in older compared with young sedentary adults (P<0.05), but only 40% lower in older adults who performed habitual endurance exercise (P=0.03). In a regression model that included age, sex, resting heart rate, mean arterial pressure (MAP), body mass index and maximal exercise oxygen uptake, estimated aortic PWV (β±s.e.=-5.76±2.01, P=0.01) was the strongest predictor of BRS (model R(2)=0.59, P<0.001). The 8-week-exercise intervention improved BRS by 38% (P=0.04) and this change in BRS was associated with improved aortic PWV (r=-0.65, P=0.044, adjusted for changes in MAP). Age- and endurance-exercise-related differences in cardiac BRS are independently associated with corresponding alterations in aortic PWV among healthy adults, consistent with a mechanistic link between variations in the sensitivity of the baroreflex and aortic stiffness with age and exercise. PMID:26911535

  5. Acute aortic occlusion as an unusual embolic complication of cardiac myxoma

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian; DUAN Zhi-quan; WANG Chuan-jiang; SONG Qing-bin; LUO Ying-wei; XIN Shi-jie

    2006-01-01

    @@ Acute aortic occlusion is an infrequent but dangerous vascular emergency with a mortality rate of 50%,1 resulting from aortic saddle embolus, thrombosis of an atherosclerotic abdominal aorta, or sudden thrombosis of a small abdominal aortic aneurysm.

  6. Aortic tear and dissection related to connective tissues abnormalities resembling Marfan syndrome in a Great Dane.

    Science.gov (United States)

    Lenz, Jennifer A; Bach, Jonathan F; Bell, Cynthia M; Stepien, Rebecca L

    2015-06-01

    Aortic tears and acute aortic dissection are rarely reported in dogs. This report describes a case of aortic dissection and probable sinus of Valsalva rupture in a young Great Dane with associated histopathologic findings suggestive of a connective tissue abnormality.

  7. [Thoracic Endovascular Aortic Repair Following Axillo-femoral Bypass in a Patient with Stanford B Acute Aortic Dissection Accompanied by Abdominal Visceral Ischemia;Report of a Case].

    Science.gov (United States)

    Nishimoto, Takayuki; Bonkohara, Yukihiro; Azuma, Takashi; Iijima, Masaki; Higashidate, Masafumi

    2016-09-01

    A 60-year-old woman was transfer-red to the emergency department of our medical center with worsening chest and back pain. Computed tomography revealed Stanford type B aortic dissection. There was a false lumen from the distal arch to the abdominal aorta just above the celiac artery. Although she was at 1st treated conservatively, she abruptly developed acute renal failure and lower limb ischemia because of an enlarged false lumen, and emergency axillo-femoral bypass surgery was performed with an 8 mm tube graft. However, renal failure gradually worsened, which necessitated continuous hemodiafiltration was performed. Thoracic endovascular aortic repair was then performed, and her renal function recovered. PMID:27586321

  8. [Use of sutureless prosthetic aortic valves in cardiac surgery].

    Science.gov (United States)

    Santarpino, Giuseppe; Fischlein, Theodor

    2014-03-01

    In the last years, an increasing proportion of high-risk patients undergo surgical aortic valve replacement. In order to reduce the risk associated with cross-clamp time or cardioplegic ischemic time, sutureless aortic prostheses have been developed. These bioprosthetic valves are not hand sewn, and this technological advance translates into reduced implantation times, thus improving outcome of patients referred for aortic valve replacement. At present, three sutureless bioprostheses are available on the market: 3f Enable (Medtronic Inc., Minneapolis, Minnesota, USA), Perceval (Sorin Group, Saluggia, Italy) and Intuity (Edwards Lifesciences, Irvine, California, USA). This article provides an overview of the available literature on sutureless aortic valves with the aim to better define current role and future perspectives of sutureless aortic bioprostheses for the treatment of aortic valve stenosis. PMID:24770430

  9. Adjusting parameters of aortic valve stenosis severity by body size

    DEFF Research Database (Denmark)

    Minners, Jan; Gohlke-Baerwolf, Christa; Kaufmann, Beat A;

    2014-01-01

    BACKGROUND: Adjustment of cardiac dimensions by measures of body size appears intuitively convincing and in patients with aortic stenosis, aortic valve area (AVA) is commonly adjusted by body surface area (BSA). However, there is little evidence to support such an approach. OBJECTIVE: To identify...... the adequate measure of body size for the adjustment of aortic stenosis severity. METHODS: Parameters of aortic stenosis severity (jet velocity, mean pressure gradient (MPG) and AVA) and measures of body size (height, weight, BSA and body mass index (BMI)) were analysed in 2843 consecutive patients with aortic...... stenosis (jet velocity ≥2.5 m/s) and related to outcomes in a second cohort of 1525 patients from the Simvastatin/Ezetimibe in Aortic Stenosis (SEAS) study. RESULTS: Whereas jet velocity and MPG were independent of body size, AVA was significantly correlated with height, weight, BSA and BMI (Pearson...

  10. Diagnosis of aortic aneurysms by scintigraphy and ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Caille, G. (Centre Hospitalier, Saint-Nazaire (France)); Chatal, J.F.; Tellier, J.L.; Talmant, C.; Guihard, R. (Centre Rene-Gauducheau, 44 - Nantes (France))

    1981-10-01

    Angioscintigraphy, performed on 50 patients suspected of aortic aneurysm and complemented by abdominal ultrasonography in 31 cases, disclosed: - Three cases of thoracic aortic aneurysm, 2 of which were confirmed by arteriography and surgery. It was impossible to perform surgery in the third case, no arteriography was done. Strict agreement with standard thoracic images had made the angioscintigraphic diagnosis seem correct. Twenty-seven cases of abdominal aortic aneurysms were confirmed by arteriography or surgery. Ultrasonography disclosed an abdominal aortic aneurysm in 26 cases, 20 of which were confirmed. The agreement of the two procedures in 10 unconfirmed cases led us to consider the diagnosis as correct. Angioscintigraphy appears to be a reliable procedure for detecting thoracic and abdominal aortic aneurysms. Ultrasonography is the simplest and least costly procedure for study of abdominal aortic aneurysms.

  11. Diagnosis of aortic aneurysms by scintigraphy and ultrasonography

    International Nuclear Information System (INIS)

    Angioscintigraphy, performed on 50 patients suspected of aortic aneurysm and complemented by abdominal ultrasonography in 31 cases, disclosed: - Three cases of thoracic aortic aneurysm, 2 of which were confirmed by arteriography and surgery. It was impossible to perform surgery in the third case, no arteriography was done. Strict agreement with standard thoracic images had made the angioscintigraphic diagnosis seems correct. - Twenty-seven cases of abdominal aortic aneurysms confirmed by arteriography or surgery. Ultrasonography disclosed an abdominal aortic aneurysm in 26 cases, 20 of which were confirmed. The agreement of the two procedures in 10 unconfirmed cases led us to consider the diagnosis as correct. Angioscintigraphy appears to be a reliable procedure for detecting thoracic and abdominal aortic aneurysms. Ultrasonography is the simplest and least costly procedure for study of abdominal aortic aneurysms

  12. Small aortic valve annulus in children with fixed subaortic stenosis.

    Science.gov (United States)

    Thilenius, O G; Campbell, D; Bharati, S; Lev, M; Arcilla, R A

    1989-01-01

    Twenty-one hearts with fixed subaortic stenosis (FSAS) were examined pathologically. Thirty children with no hemodynamically significant heart disease, 31 children with valvar aortic stenosis, and 25 children with FSAS were studied by echo- and angiocardiography. The following conclusions were drawn: (1) Patients with FSAS often have abnormal aortic valve leaflets as well as small aortic valve annulus. (2) A small aortic annulus/descending aorta ratio is probably present at birth, and may decrease with increasing age. (3) In some patients with FSAS the aortic valve annulus is too small for simple resection of the fibroelastic tissue. A Konno operation is needed for these patients. (4) M-mode echocardiography has not been useful in identifying abnormally small aortic valve annulus in FSAS patients.

  13. Fluid dynamics of aortic root dilation in Marfan syndrome

    CERN Document Server

    Querzoli, Giorgio; Espa, Stefania; Costantini, Martina; Sorgini, Francesca

    2014-01-01

    Aortic root dilation and propensity to dissection are typical manifestations of the Marfan Syndrome (MS), a genetic defect leading to the degeneration of the elastic fibres. Dilation affects the structure of the flow and, in turn, altered flow may play a role in vessel dilation, generation of aneurysms, and dissection. The aim of the present work is the investigation in-vitro of the fluid dynamic modifications occurring as a consequence of the morphological changes typically induced in the aortic root by MS. A mock-loop reproducing the left ventricle outflow tract and the aortic root was used to measure time resolved velocity maps on a longitudinal symmetry plane of the aortic root. Two dilated model aortas, designed to resemble morphological characteristics typically observed in MS patients, have been compared to a reference, healthy geometry. The aortic model was designed to quantitatively reproduce the change of aortic distensibility caused by MS. Results demonstrate that vorticity released from the valve ...

  14. Effect of abdominal aortic grafts on aortic stiffness and central hemodynamics.

    Science.gov (United States)

    Lantelme, Pierre; Dzudie, Anastase; Milon, Hugues; Bricca, Giampiero; Legedz, Liliana; Chevalier, Jean-Michel; Feugier, Patrick

    2009-06-01

    Graft-prosthesis and stentgraft placements are effective modalities for treating abdominal aortic aneurysm, but related changes in arterial stiffness are not well established. The present study sought to assess aortic stiffness after aneurism repair by measuring pulse wave velocity (PWV). The graft-related variation of carotid-femoral PWV was compared with that of carotid-radial PWV, the latter being unaffected by vascular treatment. The secondary objective was to evaluate potential differences between graft-prosthesis and stentgraft in terms of aortic stiffness and augmentation index, a composite indicator integrating wave reflexion. Fifty patients were included (39 had a graft-prosthesis and 11 had a stentgraft). In the whole group and after a median postoperative follow-up of 47 days, carotid-femoral PWV increased by +1.0 m/s [-12.3, +10.3], while carotid-radial PWV slightly decreased by -0.3 m/s [-4.4; +3.5] (P = 0.001). The effect of the type of prosthesis on the PWV was not significant. Nevertheless, the augmentation index increased after stentgraft implantation (+4% [-10; +17]) and decreased after graft-prosthesis placement (-8.5% [-47; +17]) (P aortic grafts on aortic stiffness. Besides, it suggests that stentgraft increases reflected waves more than graft-prostheses. These changes of vascular properties may influence the outcomes after surgery. PMID:19342960

  15. Recent developments for surgical aortic valve replacement: the concept of sutureless valve technology

    OpenAIRE

    Carrel, Thierry; Englberger, Lars; Stalder, Mario

    2013-01-01

    Aortic stenosis has become the most frequent type of valvular heart disease in Europe and North America and presents in the large majority of patients as calcified aortic stenosis in adults of advanced age. Surgical aortic valve replacement has been recognized to be the definitive therapy which improves considerably survival for severe aortic stenosis since more than 40 years. In the most recent period, operative mortality of isolated aortic valve replacement for aortic stenosis varies betwee...

  16. Aortic incompetence in HLA B27-positive juvenile arthritis.

    OpenAIRE

    Kean, W F; Anastassiades, T. P.; Ford, P M

    1980-01-01

    The early onset of isolated aortic incompetence in a male child with HLA B27 and peripheral arthritis is reported. Acute anterior uveitis and lone aortic incompetence occurred at 1 and 9 months respectively after the development of the acute inflammatory arthritis. The uveitis resolved with local therapy and the arthritis remitted 10 months after the onset. There has been no recurrence of the arthritis after 10 years of close follow-up but the aortic incompetence has persisted, though it rema...

  17. Use of omental pedicles in mycotic abdominal aortic aneurysm repair

    OpenAIRE

    Alibhai, M.K.; Samee, A; Ahmed, M.; Duffield, R.

    2011-01-01

    We report a case of a sixty year old man with a mycotic infra-renal abdominal aortic aneurysm complicated by a left psoas abscess. After treatment with parenteral antibiotics he underwent early aortic reconstruction with an in-situ prosthetic graft wrapped in an omental pedicle. Mycotic abdominal aortic aneurysms can be treated in this way despite the potential for graft infection from persisting retroperitoneal sepsis.

  18. Aortic stiffness: pathophysiology, clinical implications, and approach to treatment

    OpenAIRE

    Sethi S; Rivera O.; Oliveros R; Chilton R

    2014-01-01

    Salil Sethi, Oscar Rivera, Rene Oliveros, Robert Chilton University of Texas Health Science Center, San Antonio, TX, USA Abstract: Aortic stiffness is a hallmark of aging, and classic cardiovascular risk factors play a role in accelerating this process. Current changes in medicine, which focus on preventive care, have led to a growing interest in noninvasive evaluation of aortic stiffness. Aortic stiffness has emerged as a good tool for further risk stratification because it has been linked ...

  19. Giant aortic arch aneurysm complicating Kawasaki′s disease

    OpenAIRE

    Kaouthar Hakim; Rafik Boussada; Lilia Chaker; Fatma Ouarda

    2014-01-01

    Kawasaki disease (KD) is a common acute vasculitis in pediatric population that usually involves small- and middle-sized arteries, commonly coronary arteries. Although the incidence and natural course of coronary aneurysms after KD are well documented in studies, related reports on peripheral arterial and aortic aneurysms are scarce. We report the occurrence of a giant aortic aneurysm involving the horizontal part of aortic arch in a 28-month-old boy diagnosed with KD. This complication was m...

  20. DEGENERATIVE AORTIC STENOSIS: PATHOGENESIS AND NEW PRINCIPLES OF TREATMENT

    OpenAIRE

    O. V. Andropova; V. N. Anokhin

    2016-01-01

    Aim. To reveal of markers of inflammation and progression of calcification in patients with degenerative aortic stenosis (DAS). Material and methods. A single-stage study was done in 85 patients with degenerative calcification of aortic valve (42 patients with DAS and 43 patients without DAS). The techniques for assessing the severity of aortic valve calcification included ultrasonic diagnostics and multislice spiral computed tomography. Markers of inflammation and lipid profile were investig...

  1. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas;

    2010-01-01

    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacement....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  2. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas;

    2010-01-01

    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  3. Acute aortic and mitral valve regurgitation following blunt chest trauma.

    Science.gov (United States)

    Bernabeu, Eduardo; Mestres, Carlos A; Loma-Osorio, Pablo; Josa, Miguel

    2004-03-01

    Traumatic rupture of intracardiac structures is an uncommon phenomenon although there are a number of reports with regards to rupture of the tricuspid, mitral and aortic valves. We report the case of a 25-year-old patient who presented with acute aortic and mitral valve regurgitation of traumatic origin. Both lesions were seen separated by 2 weeks. Pathophysiology is reviewed. The combination of both aortic and mitral lesions following blunt chest trauma is almost exceptional.

  4. Acute aortic syndromes: Role of multi-detector row CT

    Energy Technology Data Exchange (ETDEWEB)

    Salvolini, Luca; Renda, Pietro [Department of Radiology, University ' Politecnica delle Marche' , Ancona (Italy); Fiore, Davide [Department of Radiology, University of Padova, Padova (Italy); Scaglione, Mariano [Emergency and Trauma CT Section, Department of Radiology, Cardarelli Hospital, Naples (Italy); Piccoli, GianPiero [Cardiosurgery Division, Ospedali Riuniti ' Torrette-Lancisi-Salesi' , Ancona (Italy); Giovagnoni, Andrea [Department of Radiology, University ' Politecnica delle Marche' , Ancona (Italy)], E-mail: a.giovagnoni@univpm.it

    2008-03-15

    Acute thoracic aortic syndromes encompass a spectrum of emergencies including aortic dissection, intramural haematoma, penetrating atherosclerotic ulcer and aneurysm rupture. All these life-threatening conditions require prompt diagnosis and appropriate management. To date multi-detector row Computed Tomography represents a valuable diagnostic tool especially in the emergency setting. This paper focus on the use of multi-detector row Computed Tomography in the evaluation of acute thoracic aortic syndromes and illustrates the key imaging findings related to each disease.

  5. Six axis force feedback input device

    Science.gov (United States)

    Ohm, Timothy (Inventor)

    1998-01-01

    The present invention is a low friction, low inertia, six-axis force feedback input device comprising an arm with double-jointed, tendon-driven revolute joints, a decoupled tendon-driven wrist, and a base with encoders and motors. The input device functions as a master robot manipulator of a microsurgical teleoperated robot system including a slave robot manipulator coupled to an amplifier chassis, which is coupled to a control chassis, which is coupled to a workstation with a graphical user interface. The amplifier chassis is coupled to the motors of the master robot manipulator and the control chassis is coupled to the encoders of the master robot manipulator. A force feedback can be applied to the input device and can be generated from the slave robot to enable a user to operate the slave robot via the input device without physically viewing the slave robot. Also, the force feedback can be generated from the workstation to represent fictitious forces to constrain the input device's control of the slave robot to be within imaginary predetermined boundaries.

  6. Input and Second Language Acquisition

    Institute of Scientific and Technical Information of China (English)

    周笑盈

    2011-01-01

    The behaviorist, the mentalist and the interactionist have different emphases on the role input in Second Language Acquisition. In order to protrude the importance of second language teaching, it is indispensible to discuss the characteristics of input and to explore its effects.

  7. REEXAMINING THE ROLE OF INPUT AND THE FEATURES OF OPTIMAL INPUT (Ⅱ) Features of Optimal Input

    Institute of Scientific and Technical Information of China (English)

    Niu; Qiang

    2001-01-01

    If input plays a significant role in SLA, then the nextquestion is what kind of input is most helpful to the learner?Krashen (1982) defined that optimal input should (1) becomprehensible; (2) be interesting and/or relevant; (3) not begrammatically sequened; (4) be in sufficient quantity. Wemade some modifications to this list which may still not becomprehensive either. However, if the learner can be exposed toinput having these features, it is considered that acquisition ismore likely to occur. Such input should be comprehensible,authentic, attractive and interesting, interactive, up-to-date,culture-bearing, and in great quantity.

  8. Glucose Suppresses Biological Ferroelectricity in Aortic Elastin

    Science.gov (United States)

    Liu, Yuanming; Wang, Yunjie; Chow, Ming-Jay; Chen, Nataly Q.; Ma, Feiyue; Zhang, Yanhang; Li, Jiangyu

    2013-04-01

    Elastin is an intriguing extracellular matrix protein present in all connective tissues of vertebrates, rendering essential elasticity to connective tissues subjected to repeated physiological stresses. Using piezoresponse force microscopy, we show that the polarity of aortic elastin is switchable by an electrical field, which may be associated with the recently discovered biological ferroelectricity in the aorta. More interestingly, it is discovered that the switching in aortic elastin is largely suppressed by glucose treatment, which appears to freeze the internal asymmetric polar structures of elastin, making it much harder to switch, or suppressing the switching completely. Such loss of ferroelectricity could have important physiological and pathological implications from aging to arteriosclerosis that are closely related to glycation of elastin.

  9. Spontaneous aortic dissecting hematoma in two dogs.

    Science.gov (United States)

    Boulineau, Theresa Marie; Andrews-Jones, Lydia; Van Alstine, William

    2005-09-01

    This report describes 2 cases of spontaneous aortic dissecting hematoma in young Border Collie and Border Collie crossbred dogs. Histology was performed in one of the cases involving an unusual splitting of the elastin present within the wall of the aorta, consistent with elastin dysplasia as described in Marfan syndrome in humans. The first case involved a young purebred Border Collie that died suddenly and the second case involved a Border Collie crossbred dog that died after a 1-month history of seizures. Gross lesions included pericardial tamponade with dissection of the ascending aorta in the former case and thoracic cavity hemorrhage, mediastinal hematoma, and aortic dissection in the latter. Histologic lesions in the case of the Border Collie crossbred dog included a dissecting hematoma of the ascending aorta with elastin dysplasia and right axillary arterial intimal proliferation. PMID:16312247

  10. Evaluation of regional aortic distensibility using color kinesis.

    Science.gov (United States)

    Kato, Yoshimasa; Kotoh, Keiju; Yamashita, Akio; Furuta, Hidetoshi; Shimazu, Chikasi; Misaki, Takurou

    2003-01-01

    Regional aortic stiffness cannot be evaluated by conventional methods. Regional aortic wall velocity during systole in the descending aorta was evaluated by using transesophageal echocardiography with color kinesis. The authors defined regional aortic distensibility (RAD) by considering pulse pressure, with RAD (microm/s/mm Hg) = (regional aortic wall velocity)/(pulse pressure). RAD was evaluated in 38 patients who had coronary artery disease (CAD) and 10 who did not. RAD decreased depending on aging (partial regression coefficient was -5.39 x 10(-1), pkinesis provides information on characteristic difference between calcified and noncalcified plaque.

  11. Aortic aneurysm disease vs. aortic occlusive disease - differences in outcome and intensive care resource utilisation after elective surgery

    DEFF Research Database (Denmark)

    Bisgaard, Jannie; Gilsaa, Torben; Rønholm, Ebbe;

    2013-01-01

    clamping is more pronounced in patients with aortic aneurysm disease, which may affect outcome. OBJECTIVES: The aim of this observational cohort study was to evaluate outcome after open elective abdominal aortic surgery, hypothesising a higher 30-day mortality, a higher incidence of postoperative organ...... dysfunction and a longer length of stay in patients with aortic aneurysm compared with aortic occlusive disease. DESIGN: Cohort observational study based on prospective registrations from national databases. SETTING: Eight Danish hospitals, including four university and four non-university centres, from 1...... or inotropes, ICU stay more than 24 h, hospital length of stay and mortality. RESULTS: Compared with aortic occlusive disease, more patients with aortic aneurysm disease had ICU stays more than 24 h (62 vs. 45%, P ...

  12. Aortic Disease in the Young: Genetic Aneurysm Syndromes, Connective Tissue Disorders, and Familial Aortic Aneurysms and Dissections

    Directory of Open Access Journals (Sweden)

    Marcelo Cury

    2013-01-01

    Full Text Available There are many genetic syndromes associated with the aortic aneurysmal disease which include Marfan syndrome (MFS, Ehlers-Danlos syndrome (EDS, Loeys-Dietz syndrome (LDS, familial thoracic aortic aneurysms and dissections (TAAD, bicuspid aortic valve disease (BAV, and autosomal dominant polycystic kidney disease (ADPKD. In the absence of familial history and other clinical findings, the proportion of thoracic and abdominal aortic aneurysms and dissections resulting from a genetic predisposition is still unknown. In this study, we propose the review of the current genetic knowledge in the aortic disease, observing, in the results that the causative genes and molecular pathways involved in the pathophysiology of aortic aneurysm disease remain undiscovered and continue to be an area of intensive research.

  13. Animal Models of Calcific Aortic Valve Disease

    OpenAIRE

    Sider, Krista L.; Blaser, Mark C.; Simmons, Craig A.

    2011-01-01

    Calcific aortic valve disease (CAVD), once thought to be a degenerative disease, is now recognized to be an active pathobiological process, with chronic inflammation emerging as a predominant, and possibly driving, factor. However, many details of the pathobiological mechanisms of CAVD remain to be described, and new approaches to treat CAVD need to be identified. Animal models are emerging as vital tools to this end, facilitated by the advent of new models and improved understanding of the u...

  14. Diagnostic imaging of abdominal aortic aneurysms

    International Nuclear Information System (INIS)

    The survey explains the available methods for diagnostic imaging of aortic aneurysms, i.e. the conventional methods of ultrasonography and intra-arterial angiography as well as the modern tomographic and image processing techniques such as CT, DSA, and MRT. The various methods are briefly discussed with respect to their sensitivity and specificity. The authors expect that MRI will become the modality of choice, due to absence of radiation exposure of the patients

  15. Incidence of patients with acute aortic dissection

    OpenAIRE

    Salkovski, Safet; Panova, Gordana; Velickova, Nevenka; Panova, Blagica; Panov, Nenad; Nikolovska, Lence; Dzidrova, Violeta

    2012-01-01

    Introduction: Acute aortic dissection (AAD) e life-threatening condition that characterizes the high mortality worldwide (7-8%). When AAD is split in the wall of the aorta where the blood circulates between layers of the wall which can lead to its rupture. Early recognition of symptoms and appropriate response to the medical team is crucial to the outcome of the patient. On receipt of a patient with chest pain to bear in mind the possibility of AAD. Standard diagnostics when fasti...

  16. Thrombocytosis following splenectomy and aortic valve replacement for idiopathic thrombocytopaenic purpura with bicuspid aortic valve

    Directory of Open Access Journals (Sweden)

    Sarika Katiyar

    2015-01-01

    Full Text Available Idiopathic thrombocytopaenic purpura (ITP patients are at high risk for complications during and after cardiac surgeries involving cardiopulmonary bypass. The main clinical problem of primary ITP is an increased risk of bleeding although bleeding may not always be present. More recently, thrombosis has become appreciated as another potential complication of the procedure. We report a 22-year-old female patient with ITP with bicuspid aortic valve and splenomegaly, who underwent uncomplicated aortic valve replacement and splenectomy simultaneously. She was readmitted with chest pain due to coronary thrombosis following splenectomy which made the management difficult. We describe our experience in managing this patient who presented with thrombotic complication rather than bleeding in post-operative period and the challenges met in maintaining appropriate anticoagulation for aortic valve replacement as well as thrombosis, post-splenectomy

  17. Myocardial Infarction and Aortic Root Mycotic Aneurysm Complicating Aortic Valve Endocarditis: Utility of Cardiac CT.

    Science.gov (United States)

    Moores, Aimee E; Cahill, Michael S; Villines, Todd C

    2016-01-01

    Aortic mycotic aneurysms are a rare but life-threatening potential complication of infective endocarditis. Rapid deterioration of the vascular wall in highly focal areas makes these pseudoaneurysms particularly prone to rupture, resulting in uncontrolled aortic hemorrhage. While computed tomography angiography (CTA) is the imaging modality of choice for the evaluation of mycotic aneurysms, it is not routinely performed in patients with known or suspected infective endocarditis (IE). However, current valvular heart disease guidelines support the use of cardiac CTA in cases of IE and suspected perivalvular extension when there is inadequate or ambiguous visualization on echocardiography. Here, we describe a case of IE in which cardiac CTA was used for two purposes: to assess perivalvular complications and to define coronary anatomy in a patient with a suspected embolic myocardial infarction. Subsequent detection of an aortic root mycotic aneurysm not previously demonstrated on transthoracic or transesophageal echocardiography allowed for timely and uncomplicated surgical intervention, while avoiding invasive coronary angiography. PMID:27642299

  18. Techniques for aortic arch endovascular repair.

    Science.gov (United States)

    kHONGKU, Kiattisak; Dias, Nuno; Sonesson, Bjorn; Resch, Timothy

    2016-06-01

    This article reviews endovascular strategies for aortic arch repair. Open repair remains the gold standard particularly for good risk patients. Endovascular treatment potentially offers a less invasive repair. Principles, technical considerations, devices and outcomes of each technique are discussed and summarized. Hybrid repair combines less invasive revascularization options, instead of arch replacement while extending stent-graft into the arch. Outcomes vary with regard to extent of repair and aortic arch pathologies treated. Results of arch chimney and other parallel graft techniques perhaps make it a less preferable choice for elective cases. However, they are very appealing options for urgent or bailout situations. Fenestrated stent-grafting is subjected to many technical challenges in aortic arch due to difficulties in stent-graft orientation and fenestration positioning. In situ fenestration techniques emerge to avoid these problems, but durability of stent-grafts after fenestration and ischemic consequences of temporary carotid arteries coverage raises some concern total arch repair using this technique. Arch branched graft is a new technology. Early outcomes did not meet the expectation; however the results have been improving after its learning curve period. Refining stent-graft technologies and implantation techniques positively impact outcomes of endovascular approaches. PMID:26940011

  19. Volumetric analysis of abdominal aortic aneurysm

    Science.gov (United States)

    Baskin, Kevin M.; Kusnick, Catherine A.; Shamsolkottabi, Susanne; Lang, Elvira V.; Corson, J. D.; Stanford, William; Thompson, Brad H.; Hoffman, Eric A.

    1996-04-01

    The purpose of this study was to develop a valid, reliable and accurate system of measurement of abdominal aortic aneurysms, using volumetric analysis of x-ray computed tomographic data. This study evaluates illustrative cases, and compares measurements of AAA phantoms, using standard 2D versus volumetric methods. To validate the volumetric analysis, four phantom aneurysms were constructed in a range of diameters (4.5 - 7.0 cm) which presents the greatest management challenge to the clinician. These phantoms were imaged using a Toshiba Xpress SX helical CT. Separate scans were obtained at conventional (10 mm X 10 mm) and thin slice (5 mm X 5 mm) collimations. The thin slices were reconstructed at 2 mm intervals. Data from each of the 96 scans were interpreted using a standard 2D approach, then analyzed using task-oriented volumetric software. We evaluate patient assessments, and compare greatest outer diameters of phantoms, by standard versus volumetric methods. Qualitative differences between solutions based on standard versus volumetric analysis of illustrative patient cases are substantial. Expert radiologists' standard measurements of phantom aneurysms are highly reliable (r2 equals 0.901 - 0.958; p aneurysm diameters in the range of clinical interest. For the same phantoms, volumetric analysis was both more reliable (r2 equals 0.986 - 0.996; p abdominal aortic aneurysms. It is particularly valuable in the presence of aortic tortuosity, vessel eccentricity, and uncertain involvement of critical vessels.

  20. Recurrent Pneumonia due to Double Aortic Arch

    Directory of Open Access Journals (Sweden)

    I. Sedighi

    2012-04-01

    Full Text Available Introduction: Pneumonia is one of the most common infections during childhood. In children with recurrent bacterial pneumonia complete evaluation for underlying factors is necessary. The most common underlying diseases include: antibody deficiencies , cystic fibrosis , tracheoesophageal fistula and increased pulmonary blood flow. Vascular ring and its pressure effect is a less common cause of stridor and recurrent pneumonia. Congenital abnormalities in aortic arch and main branches which form vascular ring around esophagus and trachea with variable pressure effect cause respiratory symptoms such as stridor , wheezing and recurrent pneumoniaCase Report: A 2 year old boy was admitted in our hospital with respiratory distress and cough . Chest x-Ray demonstrated right lobar pneumonia. He had history of stridor and wheezing from neonatal period and hospitalization due to pneumonia for four times. The patient received appropriate antibiotics. Despite fever and respiratory distress improvement, wheezing continued. Review of his medical documents showed fixed pressure effect on posterior aspect of esophagus in barium swallow. In CT angiography we confirmed double aortic arch.Conclusion: Double aortic arch is one of the causes of persistant respiratory symptom and recurrent pneumonia in children for which fluoroscopic barium swallow is the first non-invasive diagnostic method.(Sci J Hamadan Univ Med Sci 2012;19(1:70-74

  1. Acute aortic dissection: be aware of misdiagnosis

    Directory of Open Access Journals (Sweden)

    Asteri Theodora

    2009-02-01

    Full Text Available Abstract Background Acute aortic dissection (AAD is a life-threatening condition requiring immediate assessment and therapy. A patient suffering from AAD often presents with an insignificant or irrelevant medical history, giving rise to possible misdiagnosis. The aim of this retrospective study is to address the problem of misdiagnosing AD and the different imaging studies used. Methods From January 2000 to December 2004, 49 patients (41 men and 8 women, aged from 18–75 years old presented to the Emergency Department of our hospital for different reasons and finally diagnosed with AAD. Fifteen of those patients suffered from arterial hypertension, one from giant cell arteritis and another patient from Marfan's syndrome. The diagnosis of AAD was made by chest X-ray, contrast enhanced computed tomography (CT, transthoracic echocardiography (TTE and coronary angiography. Results Initial misdiagnosis occurred in fifteen patients (31% later found to be suffering from AAD. The misdiagnosis was myocardial infarction in 12 patients and cerebral infarction in another three patients. Conclusion Aortic dissection may present with a variety of clinical manifestations, like syncope, chest pain, anuria, pulse deficits, abdominal pain, back pain, or acute congestive heart failure. Nearly a third of the patients found to be suffering from AD, were initially otherwise diagnosed. Key in the management of acute aortic dissection is to maintain a high level of suspicion for this diagnosis.

  2. Cadaveric aorta implantation for aortic graft infection.

    Science.gov (United States)

    Ali, Asad; Bahia, Sandeep S S; Ali, Tahir

    2016-01-01

    This case report describes a 73-year-old gentleman who underwent explantation of an infected prosthetic aorto-iliac graft and replacement with a cryopreserved thoracic and aorto-iliac allograft. The patient has been followed up a for more than a year after surgery and remains well. After elective tube graft repair of his abdominal aortic aneurysm (AAA) in 2003, he presented to our unit in 2012 in cardiac arrest as a result of a rupture of the distal graft suture line due to infection. After resuscitation he underwent aorto-bifemoral grafting using a cuff of the original aortic graft proximally. Distally the new graft was anastomosed to his common femoral arteries, with gentamicin beads left in situ. Post discharge the patient was kept under close surveillance with serial investigations including nuclear scanning, however it became apparent that his new graft was infected and that he would require aortic graft replacement, an operation with a mortality of at least 50%. The patient underwent the operation and findings confirmed a synthetic graft infection. This tube graft was explanted and a cryopreserved aorta was used to the refashion the abdominal aorta and its bifurcation. The operation required a return to theatre day one post operatively for a bleeding side branch, which was repaired. The patient went on to make a full recovery stepping down from the intensive therapy unit day 6 post operatively and went on to be discharged 32 days after his cryopreserved aorta implantation. PMID:27351624

  3. Surgery for abdominal aortic aneurysms. A survey of 656 patients

    DEFF Research Database (Denmark)

    Olsen, P S; Schroeder, T; Agerskov, Kim;

    1991-01-01

    Between 1979 and 1988, 656 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed in 287 patients (44%) and acute operation in 369 patients. A ruptured aneurysm was found in 218 patients (33%). Patients with arteriosclerotic heart disease, hypertension, impaired...... renal function or chronic pulmonary disease showed an increased perioperative mortality. Development of postoperative cardiac and renal complications could not be related to previous cardiac or renal diseases. The major postoperative complications were renal failure in 81 patients (12%), pulmonary...... insufficiency in 77 patients (11%) and cardiac complications in 96 patients (13%). Failure of one or more organs occurred in 153 patients (23%) and the mortality rate for patients with multiorgan failure was 68%. Complications leading to reoperation occurred in 93 patients (14%). The perioperative mortality...

  4. HAS-1 genetic polymorphism in sporadic abdominal aortic aneurysm

    Directory of Open Access Journals (Sweden)

    Alberto Balbarini

    2009-04-01

    Full Text Available The hyaluronan synthase 1 (HAS-1 gene encodes a plasma membrane protein that synthesizes hyaluronan (HA, an extracellular matrix molecule. Accumulating evidence emphasizes the relevance of HA metabolism in an increasing number of processes of clinical interest, including abdominal aortic aneurysm (AAA. The existence of aberrant splicing variants of the HAS-1 gene could partly explain the altered extracellular matrix architecture and influence various biological functions, resulting in progressive arterial wall failure in the development of AAA. In the present study, we assessed the hypothesis that HAS-1 genetic 833A/G polymorphism could be associated with the risk of AAA by performing a case-control association study, involving AAA patients and healthy matched donors.

  5. Comparative in Vitro Research of the Human Aortic Bioprosthesis

    Directory of Open Access Journals (Sweden)

    Dawidowska K.

    2014-12-01

    Full Text Available Evaluate of the usefulness and reliability of structures based on the analysis of recorded parameters determining the flow through the Human Aortic Bioprosthesis (HAB have been dealt with. By flow parameters changes determining the performance environment of prosthesis analyzed change of the motion dynamics of the valve leaflets as a function of pressure, thereby determining the degree of alignment of the prosthesis to the performance conditions. Based on the gathered measurement data a comparative analysis of flow rate valve prostheses for different frequency values of the piston pump imitating the heart, different ejection capacity and pressure conditioning work environment prosthesis were studied. Interpretation of the recorded image gave the basis for determining the Effective Orifice Area (EOC.

  6. Bicuspid aortic valves: Diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT

    International Nuclear Information System (INIS)

    Objectives: To assess the diagnostic accuracy of standard axial 64-slice chest CT compared to aortic valve image plane ECG-gated cardiac CT for bicuspid aortic valves. Materials and methods: The standard axial chest CT scans of 20 patients with known bicuspid aortic valves were blindly, randomly analyzed for (i) the appearance of the valve cusps, (ii) the largest aortic sinus area, (iii) the longest aortic cusp length, (iv) the thickest aortic valve cusp and (v) valve calcification. A second blinded reader independently analyzed the appearance of the valve cusps. Forty-two age- and sex-matched patients with known tricuspid aortic valves were used as controls. Retrospectively ECG-gated cardiac CT multiphase reconstructions of the aortic valve were used as the gold-standard. Results: Fourteen (21%) scans were scored as unevaluable (7 bicuspid, 7 tricuspid). Of the remainder, there were 13 evaluable bicuspid valves, ten of which showed an aortic valve line sign, while the remaining three showed a normal Mercedes-Benz appearance owing to fused valve cusps. The 35 evaluable tricuspid aortic valves all showed a normal Mercedes-Benz appearance (P = 0.001). Kappa analysis = 0.62 indicating good interobserver agreement for the aortic valve cusp appearance. Aortic sinus areas, aortic cusp lengths and aortic cusp thicknesses of ≥3.8 cm2, 3.2 cm and 1.6 mm respectively on standard axial chest CT best distinguished bicuspid from tricuspid aortic valves (P < 0.0001 for all). Of evaluable scans, the sensitivity, specificity, positive and negative predictive values of standard axial chest CT in diagnosing bicuspid aortic valves was 77% (CI 0.54–1.0), 100%, 100% and 70% respectively. Conclusion: The aortic valve is evaluable in approximately 80% of standard chest 64-slice CT scans. Bicuspid aortic valves may be diagnosed on evaluable scans with good diagnostic accuracy. An aortic valve line sign, enlarged aortic sinuses and elongated, thickened valve cusps are specific CT

  7. Coronary artery dissection with rupture of aortic valve commissure following type A aortic dissection: the role of 64-slice MDCT.

    Science.gov (United States)

    Das, K M; Abdou, Sayed M; El-Menyar, Ayman; Ayman, El Menyar; Khulaifi, A A; Nabti, A L

    2008-01-01

    A rare case of bilateral coronary artery dissection with rupture of aortic valve commissure following type A aortic dissection is described. 64-slice multidetector computed tomography (MDCT) was able to demonstrate both this findings along with involvement of other neck vessels. TEE demonstrated the severity and mechanisms of aortic valve damage and assisted the surgeon in valve repair. MDCT has played an invaluable role in the diagnosis of the abnormal details of such life-threatening vascular complications. PMID:18384568

  8. Inflammatory abdominal aortic aneurysm presenting as bilateral hydroureteronephrosis: a case report and review of literature.

    Science.gov (United States)

    Galosi, Andrea Benedetto; Grilli Cicilioni, Carlo; Sbrollini, Giulia; Angelini, Andrea; Maselli, Guevar; Carbonari, Luciano

    2014-12-01

    We report a case of Inflammatory Abdominal Aortic Aneurysm (IAAA) producing bilateral hydro-ureteronephrosis. A 74-year-old patient presented to urologist office for bilateral hydronephrosis detected by kidney and bladder ultrasound (US). Patient reported lower urinary tract symptoms and inconstant and slight low back pain irradiated to inguinal region dating 3 weeks. Renal function, urine analysis and abdominal examination were normal. However the repeated ultrasound in the urologist office revealed abdominal aortic aneurism extended to iliac vessels. The patient was sent directly to vascular surgery unit where contrast computerized tomography (CT) and successful surgical repair were done. Final diagnosis was IAAA. The post-operative course was uneventful. Renal function was regular and the hydronephrosis reduced spontaneously under monitoring by CT and US. We review diagnosis and management of hydronephrosis that is sometimes linked to IAAA rather than standard AAA. Abdominal ultrasound is mandatory in any bilateral hydronephrosis and it could save lives. PMID:25641477

  9. Inflammatory abdominal aortic aneurysm presenting as bilateral hydroureteronephrosis: A case report and review of literature

    Directory of Open Access Journals (Sweden)

    Andrea Benedetto Galosi

    2014-12-01

    Full Text Available We report a case of Inflammatory Abdominal Aortic Aneurysm (IAAA producing bilateral hydro-ureteronephrosis. A 74-year-old patient presented to urologist office for bilateral hydronephrosis detected by kidney and bladder ultrasound (US. Patient reported lower urinary tract symptoms and inconstant and slight low back pain irradiated to inguinal region dating 3 weeks. Renal function, urine analysis and abdominal examination were normal. However the repeated ultrasound in the urologist office revealed abdominal aortic aneurism extended to iliac vessels. The patient was sent directly to vascular surgery unit where contrast computerized tomography (CT and successful surgical repair were done. Final diagnosis was IAAA. The post-operative course was uneventful. Renal function was regular and the hydronephrosis reduced spontaneously under monitoring by CT and US. We review diagnosis and management of hydronephrosis that is sometimes linked to IAAA rather than standard AAA. Abdominal ultrasound is mandatory in any bilateral hydronephrosis and it could save lives.

  10. Histopathology of aortic complications in bicuspid aortic valve versus Marfan syndrome: relevance for therapy?

    Science.gov (United States)

    Grewal, Nimrat; Franken, Romy; Mulder, Barbara J M; Goumans, Marie-José; Lindeman, Johannes H N; Jongbloed, Monique R M; DeRuiter, Marco C; Klautz, Robert J M; Bogers, Ad J J C; Poelmann, Robert E; Groot, Adriana C Gittenberger-de

    2016-05-01

    Patients with bicuspid aortic valve (BAV) and patients with Marfan syndrome (MFS) are more prone to develop aortic dilation and dissection compared to persons with a tricuspid aortic valve (TAV). To elucidate potential common and distinct pathways of clinical relevance, we compared the histopathological substrates of aortopathy. Ascending aortic wall biopsies were divided in five groups: BAV (n = 36) and TAV (n = 23) without and with dilation and non-dilated MFS (n = 8). General histologic features, apoptosis, the expression of markers for vascular smooth muscle cell (VSMC) maturation, markers predictive for ascending aortic dilation in BAV, and expression of fibrillin-1 were investigated. Both MFS and BAV showed an altered distribution and decreased fibrillin-1 expression in the aorta and a significantly lower level of differentiated VSMC markers. Interestingly, markers predictive for aortic dilation in BAV were not expressed in the MFS aorta. The aorta in MFS was similar to the aorta in dilated TAV with regard to the presence of medial degeneration and apoptosis, while other markers for degeneration and aging like inflammation and progerin expression were low in MFS, comparable to BAV. Both MFS and BAV aortas have immature VSMCs, while MFS and TAV patients have a similar increased rate of medial degeneration. However, the mechanism leading to apoptosis is expected to be different, being fibrillin-1 mutation induced increased angiotensin-receptor-pathway signaling in MFS and cardiovascular aging and increased progerin in TAV. Our findings could explain why angiotensin inhibition is successful in MFS and less effective in TAV and BAV patients. PMID:26129868

  11. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... function as well as anatomy in patients who need heart surgery. It allows us, from an valvular perspective, to know the human dynamic or blood pressure effects of a valvular ...

  12. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... help evaluate both cardiac function as well as anatomy in patients who need heart surgery. It allows ... also important with regards to determining coronary artery anatomy, as some patients may need coronary bypass surgery ...

  13. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... the patient's cardiac function, look for other occult problems with the heart. And it also establishes a point of reference for us to follow patients in the future with regards ...

  14. [Neuroendovascular Treatment for Cerebral Embolism in a Patient just after Aortic Valve Replacement;Report of a Case].

    Science.gov (United States)

    Kumagai, Motoyuki; Nishizawa, Junichiro; Heima, Daisuke; Takatoku, Kazuhiro; Watanabe, Yoshihiko; Matsui, Yasuzumi; Miyake, Hidenori

    2015-12-01

    A 67-year-old woman suffered from severe aortic stenosis and atrial fibrillation, and underwent aortic valve replacement with a St. Jude Medical Regent 23-mm valve and pulmonary vein isolation using an AtriCure Isolator Synergy.At 6 days after the operation, she experienced sudden onset of atrial fibrillation, left side paralysis, and dysarthria. Right internal carotid artery embolism was diagnosed via magnetic resonance imaging, and we promptly performed neuroendovascular therapy with a Solitaire FR. Neuroendovascular treatment succeeded, and her neurological function was restored to near-normal. Her post-treatment course was uneventful, and she is currently well without neurological dysfunction. PMID:26759947

  15. Abdominal aortic aneurysm is associated with a variant in low-density lipoprotein receptor-related protein 1

    DEFF Research Database (Denmark)

    Bown, Matthew J; Jones, Gregory T; Harrison, Seamus C;

    2011-01-01

    Abdominal aortic aneurysm (AAA) is a common cause of morbidity and mortality and has a significant heritability. We carried out a genome-wide association discovery study of 1866 patients with AAA and 5435 controls and replication of promising signals (lead SNP with a p value ... demonstrated a trend toward increased LRP1 expression for the rs1466535 CC genotype in arterial tissues; there was a significant (p = 0.029) 1.19-fold (1.04-1.36) increase in LRP1 expression in CC homozygotes compared to TT homozygotes in aortic adventitia. Functional studies demonstrated that rs1466535 might...

  16. Unreliability of aortic size index to predict risk of aortic dissection in a patient with Turner syndrome

    Science.gov (United States)

    Nijs, Jan; Gelsomino, Sandro; Lucà, Fabiana; Parise, Orlando; Maessen, Jos G; Meir, Mark La

    2014-01-01

    Aortic size index (ASI) has been proposed as a reliable criterion to predict risk for aortic dissection in Turner syndrome with significant thresholds of 20-25 mm/m2. We report a case of aortic arch dissection in a patient with Turner syndrome who, from the ASI thresholds proposed, was deemed to be at low risk of aortic dissection or rupture and was not eligible for prophylactic surgery. This case report strongly supports careful monitoring and surgical evaluation even when the ASI is < 20 mm/m2 if other significant risk factors are present. PMID:24944765

  17. Qualitative Model of the Input Impedance of Rectangular Microstrip Antenna

    Directory of Open Access Journals (Sweden)

    Saeed Reza Ostadzadeh

    Full Text Available In this paper, a fuzzy-based approach is proposed so as to predict the input impedance of the rectangular microstrip antenna. In the proposed approach, at first, behavior of single microstrip antenna is represented as simple and unchanged membership functions, and the feed probe effect on the input impedance is then extracted as simple curves so that the input impedance of microstrip antenna in despite of other existing models is efficiently predicted.

  18. Doxycycline Does Not Influence Established Abdominal Aortic Aneurysms in Angiotensin II-Infused Mice

    OpenAIRE

    Xiaojie Xie; Hong Lu; Moorleghen, Jessica J.; Howatt, Deborah A.; Rateri, Debra L.; Cassis, Lisa A.; Alan Daugherty

    2012-01-01

    BACKGROUND: There is no proven medical approach to attenuating expansion and rupture of abdominal aortic aneurysms (AAAs). One approach that is currently being investigated is the use of doxycycline. Despite being primarily used as an antimicrobial drug, doxycycline has been proposed to function in reducing AAA expansion. Doxycycline is effective in reducing the formation in the most commonly used mouse models of AAAs when administered prior to the initiation of the disease. The purpose of th...

  19. Inflammatory abdominal aortic aneurysm presenting as bilateral hydroureteronephrosis: A case report and review of literature

    OpenAIRE

    Andrea Benedetto Galosi; Carlo Grilli Cicilioni; Giulia Sbrollini; Andrea Angelini; Guevar Maselli; Luciano Carbonari

    2014-01-01

    We report a case of Inflammatory Abdominal Aortic Aneurysm (IAAA) producing bilateral hydro-ureteronephrosis. A 74-year-old patient presented to urologist office for bilateral hydronephrosis detected by kidney and bladder ultrasound (US). Patient reported lower urinary tract symptoms and inconstant and slight low back pain irradiated to inguinal region dating 3 weeks. Renal function, urine analysis and abdominal examination were normal. However the repeated ultrasound in the urologist office ...

  20. Aortic pressure wave reconstruction during exercise is improved by adaptive filtering: a pilot study

    OpenAIRE

    Stok, W.J.; Westerhof, B E; Guelen, I.; Karemaker, J. M.

    2011-01-01

    Reconstruction of central aortic pressure from a peripheral measurement by a generalized transfer function (genTF) works well at rest and mild exercise at lower heart rates, but becomes less accurate during heavy exercise. Particularly, systolic and pulse pressure estimations deteriorate, thereby underestimating central pressure. We tested individualization of the TF (indTF) by adapting its resonance frequency at the various levels of exercise. In seven males (age 44–57) with coronary artery ...

  1. Cardiac rehabilitation and mid-term follow-up after transcatheter aortic valve implantation

    OpenAIRE

    Zanettini, Renzo; Gatto, Gemma; Mori, Ileana; Pozzoni, Maria Beatrice; Pelenghi, Stefano; Martinelli, Luigi; Klugmann, Silvio

    2014-01-01

    Background Evaluation of patient outcomes following transcatheter aortic valve implantation (TAVI) has usually been based on survival and clinical improvement. Studies on quality of life are limited, and data from comprehensive assessments after the procedure are lacking. Methods Sixty patients referred for cardiac rehabilitation after TAVI underwent in-hospital and after-discharge multidimensional assessments to evaluate clinical, functional, and nutritional statuses, degree of autonomy, cog...

  2. The pathology and pathobiology of bicuspid aortic valve: State of the art and novel research perspectives.

    Science.gov (United States)

    Mathieu, Patrick; Bossé, Yohan; Huggins, Gordon S; Corte, Alessandro Della; Pibarot, Philippe; Michelena, Hector I; Limongelli, Giuseppe; Boulanger, Marie-Chloé; Evangelista, Arturo; Bédard, Elisabeth; Citro, Rodolfo; Body, Simon C; Nemer, Mona; Schoen, Frederick J

    2015-10-01

    Bicuspid aortic valve is the most prevalent cardiac valvular malformation. It is associated with a high rate of long-term morbidity including development of calcific aortic valve disease, aortic regurgitation and concomitant thoracic aortic aneurysm and dissection. Recently, basic and translational studies have identified some key processes involved in the development of bicuspid aortic valve and its morbidity. The development of aortic valve disease and thoracic aortic aneurysm and dissection is the result of complex interactions between genotypes, environmental risk factors and specific haemodynamic conditions created by bicuspid aortic valve anatomy. Herein, we review the pathobiology of bicuspid aortic valve with a special emphasis on translational aspects of these basic findings. Important but unresolved problems in the pathology of bicuspid aortic valve and thoracic aortic aneurysm and dissection are discussed, along with the molecular processes involved. PMID:27499904

  3. Surgery of the aortic root: should we go for the valve-sparing root reconstruction or the composite graft-valve replacement is still the first choice of treatment for these patients?

    Directory of Open Access Journals (Sweden)

    Fernando de Azevedo Lamana

    2015-09-01

    Full Text Available AbstractObjective:To compare the results of the root reconstruction with the aortic valve-sparing operation versus composite graftvalve replacement.Methods:From January 2002 to October 2013, 324 patients underwent aortic root reconstruction. They were 263 composite graft-valve replacement and 61 aortic valve-sparing operation (43 reimplantation and 18 remodeling. Twenty-six percent of the patients were NYHA functional class III and IV; 9.6% had Marfan syndrome, and 12% had bicuspid aortic valve. There was a predominance of aneurysms over dissections (81% vs. 19%, with 7% being acute dissections. The complete follow-up of 100% of the patients was performed with median follow-up time of 902 days for patients undergoing composite graft-valve replacement and 1492 for those undergoing aortic valve-sparing operation.Results:In-hospital mortality was 6.7% and 4.9%, respectively for composite graft-valve replacement and aortic valve-sparing operation (ns. During the late follow-up period, there was 0% moderate and 15.4% severe aortic regurgitation, and NYHA functional class I and II were 89.4% and 94%, respectively for composite graft-valve replacement and aortic valve-sparing operation (ns. Root reconstruction with aortic valve-sparing operation showed lower late mortality (P=0.001 and lower bleeding complications (P=0.006. There was no difference for thromboembolism, endocarditis, and need of reoperation.Conclusion:The aortic root reconstruction with preservation of the valve should be the operation being performed for presenting lower late mortality and survival free of bleeding events.

  4. 6-month aortic valve implantation of an off-the-shelf tissue-engineered valve in sheep.

    Science.gov (United States)

    Syedain, Zeeshan; Reimer, Jay; Schmidt, Jillian; Lahti, Matthew; Berry, James; Bianco, Richard; Tranquillo, Robert T

    2015-12-01

    Diseased aortic valves often require replacement, with over 30% of the current aortic valve surgeries performed in patients who will outlive a bioprosthetic valve. While many promising tissue-engineered valves have been created in the lab using the cell-seeded polymeric scaffold paradigm, none have been successfully tested long-term in the aortic position of a pre-clinical model. The high pressure gradients and dynamic flow across the aortic valve leaflets require engineering a tissue that has the strength and compliance to withstand high mechanical demand without compromising normal hemodynamics. A long-term preclinical evaluation of an off-the-shelf tissue-engineered aortic valve in the sheep model is presented here. The valves were made from a tube of decellularized cell-produced matrix mounted on a frame. The engineered matrix is primarily composed of collagen, with strength and organization comparable to native valve leaflets. In vitro testing showed excellent hemodynamic performance with low regurgitation, low systolic pressure gradient, and large orifice area. The implanted valves showed large-scale leaflet motion and maintained effective orifice area throughout the duration of the 6-month implant, with no calcification. After 24 weeks implantation (over 17 million cycles), the valves showed no change in tensile mechanical properties. In addition, histology and DNA quantitation showed repopulation of the engineered matrix with interstitial-like cells and endothelialization. New extracellular matrix deposition, including elastin, further demonstrates positive tissue remodeling in addition to recellularization and valve function. Long-term implantation in the sheep model resulted in functionality, matrix remodeling, and recellularization, unprecedented results for a tissue-engineered aortic valve. PMID:26409002

  5. Percutaneous implantation of self-expandable aortic valve in high risk patients with severe aortic stenosis: The first experiences in Serbia

    Directory of Open Access Journals (Sweden)

    Nedeljković Milan A.

    2016-01-01

    Full Text Available Background/Aim. Aortic stenosis (AS is the most common valvular heart disease in elderly people, with rather poor prognosis in symptomatic patients. Surgical valve replacement is the therapy of choice, but a significant number of patients cannot undergo surgical procedure. We presented initial experience of transcatheter aortic valve implantation (TAVI performed in Catheterization Laboratory of the Clinic for Cardiology, Clinical Center of Serbia. Methods. The procedures were performed in 5 patients (mean age 76 ± 6 years, 2 males, 3 female with severe and symptomatic AS with contraindication to surgery or high surgical risk. The decision to perform TAVI was made by the heart team. Pre-procedure screening included detailed clinical and echocardiographic evaluation, coronary angiography and computed tomography scan. In all the patients we implanted a self-expandable aortic valve (Core Valve, Medtronic, USA. Six months follow-up was available for all the patients. Results. All interventions were successfully performed without significant periprocedural complications. Immediate hemodynamic improvement was obtained in all the patients (peak gradient 94.2 ± 27.6 to 17.6 ± 5.2 mmHg, p < 0.001, mean pressure gradient 52.8 ± 14.5 to 8.0 ± 2.1 mmHg, p < 0.001. None of the patients developed heart block, stroke, vascular complication or significant aortic regurgitation. After 6 months, the survival was 100% with New York Heart Association (NYHA functional improvement in all the patients. Conclusion. This successful initial experience provides a solid basis to treat larger number of patients with symptomatic AS and high surgical risk who are left untreated. [Projekat Ministarstva nauke Republike Srbije, br. ON 175 020

  6. A three-dimensional co-culture model of the aortic valve using magnetic levitation.

    Science.gov (United States)

    Tseng, Hubert; Balaoing, Liezl R; Grigoryan, Bagrat; Raphael, Robert M; Killian, T C; Souza, Glauco R; Grande-Allen, K Jane

    2014-01-01

    The aortic valve consists of valvular interstitial cells (VICs) and endothelial cells (VECs). While these cells are understood to work synergistically to maintain leaflet structure and valvular function, few co-culture models of these cell types exist. In this study, aortic valve co-cultures (AVCCs) were assembled using magnetic levitation and cultured for 3 days. Immunohistochemistry and quantitative reverse-transcriptase polymerase chain reaction were used to assess the maintenance of cellular phenotype and function, and the formation of extracellular matrix. AVCCs stained positive for CD31 and α-smooth muscle actin (αSMA), demonstrating that the phenotype was maintained. Functional markers endothelial nitric oxide synthase (eNOS), von Willebrand factor (VWF) and prolyl-4-hydroxylase were present. Extracellular matrix components collagen type I, laminin and fibronectin also stained positive, with reduced gene expression of these proteins in three dimensions compared to two dimensions. Genes for collagen type I, lysyl oxidase and αSMA were expressed less in AVCCs than in 2-D cultures, indicating that VICs are quiescent. Co-localization of CD31 and αSMA in the AVCCs suggests that endothelial-mesenchymal transdifferentiation might be occurring. Differences in VWF and eNOS in VECs cultured in two and three dimensions also suggests that the AVCCs possibly have anti-thrombotic potential. Overall, a co-culture model of the aortic valve was designed, and serves as a basis for future experiments to understand heart valve biology. PMID:24036238

  7. A New Cone-Shaped Aortic Valve Prosthesis for Orthotopic Position: An Experimental Study in Swine

    International Nuclear Information System (INIS)

    The aim of this experimental study was to evaluate a newly designed cone-shaped aortic valve prosthesis (CAVP) for one-step transcatheter placement in an orthotopic position. The study was conducted in 15 swine using either the transcarotid (11 animals) or the transfemoral (4 animals) artery approach. A 12- or 13-Fr sheath was inserted via arterial cutdown. The CAVP was deployed under fluoroscopic control and its struts, by design, induced significant native valve insufficiency. CAVP function was evaluated by aortography and aortic pressure curve tracing. In 11 of 15 swine the CAVP was properly deployed and functioned well throughout the scheduled period of 2-3 h. In three swine the CAVPs were placed lower than intended, however, they were functional even in the left ventricular outflow tract position. One swine expired due to inadvertent low CAVP placement that caused both aortic regurgitation and immobilization of the anterior mitral valve leaflet by the valve struts. We conclude that this design of CAVP is relatively easy to deploy, works well throughout a short time period (2-3 h), and, moreover, seems to be reliable even in a lower-than-orthotopic position (e.g., infra-annulary space). Longer-term studies are needed for its further evaluation.

  8. The Advanced LIGO Input Optics

    CERN Document Server

    Mueller, Chris; Ciani, Giacomo; DeRosa, Ryan; Effler, Anamaria; Feldbaum, David; Frolov, Valery; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; King, Eleanor; Kokeyama, Keiko; Korth, William; Martin, Rodica; Mullavey, Adam; Poeld, Jan; Quetschke, Volker; Reitze, David; Tanner, David; Williams, Luke; Mueller, Guido

    2016-01-01

    The Advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they h...

  9. Minimally Invasive Aortic Valve Replacement

    Medline Plus

    Full Text Available ... you can see the patient's heart appears to be functioning well from our perspective. Again, we use the echo ... for in a surgeon or a program? 13 Well, I think, as with any procedure, never be afraid to ask that person who's doing the ...

  10. Nonlinear input-output systems

    Science.gov (United States)

    Hunt, L. R.; Luksic, Mladen; Su, Renjeng

    1987-01-01

    Necessary and sufficient conditions that the nonlinear system dot-x = f(x) + ug(x) and y = h(x) be locally feedback equivalent to the controllable linear system dot-xi = A xi + bv and y = C xi having linear output are found. Only the single input and single output case is considered, however, the results generalize to multi-input and multi-output systems.

  11. Familial abdominal aortic aneurysm: prevalence and implications for screening.

    Science.gov (United States)

    Adams, D C; Tulloh, B R; Galloway, S W; Shaw, E; Tulloh, A J; Poskitt, K R

    1993-11-01

    The high prevalence of abdominal aortic aneurysm (AAA) in men over the age of 65 has led to the establishment of ultrasound screening programmes for this group. The apparent familial tendency towards AAA formation suggests that relatives of aneurysm patients may form another subpopulation in whom screening is appropriate. The first degree relatives of 100 consecutive aneurysm patients were identified. Of 110 relatives over 50 years of age, two were known to have had AAA and ultrasound scans were performed on 74, providing information on aortic size for 76 relatives (69%). No further aortic aneurysms (antero-posterior diameter > or = 4.0 cm) were found on scanning. However, nine relatives were demonstrated to have aortic dilatation (2.5-3.9 cm). Aortic dilatation was observed in 21% of male first degree relatives over 50 years of age, affecting 27% of sons and 17% of brothers. Only 4% of the sisters and none of the daughters were found to have aortic dilatation. The prevalence of aortic enlargement seems to be sufficiently high amongst male first degree relatives of AAA patients over 50 years of age to justify aortic screening.

  12. Application of occluders in endovascular repair of aortic aneurysms

    Institute of Scientific and Technical Information of China (English)

    SHI Zhen-yu; FU Wei-guo; WANG Yu-qi; GUO Da-qiao; CHEN Bin; JIANG Jun-hao; XU Xin; YANG Jue; ZHU Ting

    2007-01-01

    @@ Since Parodi et al1 reported the first successful case of endovascular treatment for abdominal aortic aneurysm (AAA) in 1991, the endovascular repair has become an important option for the surgical treatment of aortic aneurysms.2-4 The occluder is a newly-developed device introduced intraluminally to block the blood flow in certain arteries.

  13. Intensive lipid lowering with simvastatin and ezetimibe in aortic stenosis

    DEFF Research Database (Denmark)

    Rossebo, A.B.; Pedersen, T.R.; Boman, K.;

    2008-01-01

    BACKGROUND: Hyperlipidemia has been suggested as a risk factor for stenosis of the aortic valve, but lipid-lowering studies have had conflicting results. METHODS: We conducted a randomized, double-blind trial involving 1873 patients with mild-to-moderate, asymptomatic aortic stenosis. The patients...

  14. Decreased mortality of abdominal aortic aneurysms in a peripheral county

    DEFF Research Database (Denmark)

    Lindholt, Jes Sanddal; Henneberg, E W; Fasting, H

    1995-01-01

    To analyse the effect on the mortality associated with abdominal aortic aneurysms, due to the establishment of a decentralised vascular surgical unit in the county of Viborg.......To analyse the effect on the mortality associated with abdominal aortic aneurysms, due to the establishment of a decentralised vascular surgical unit in the county of Viborg....

  15. Statin use and rupture of abdominal aortic aneurysm

    DEFF Research Database (Denmark)

    Wemmelund, H; Høgh, A; Hundborg, H H;

    2014-01-01

    BACKGROUND: Ruptured abdominal aortic aneurysm (rAAA) is associated with high mortality. Research suggests that statins may reduce abdominal aortic aneurysm (AAA) growth and improve rAAA outcomes. However, the clinical impact of statins remains uncertain in relation to both the risk and prognosis...

  16. A comparative study of iliac and abdominal aortic aneurysms

    DEFF Research Database (Denmark)

    Vammen, Sten; Lindholt, Jes Sanddal; Henneberg, E W;

    2000-01-01

    The aim of the paper is to compare the epidemiology, risk factors and manifestations of iliac and abdominal aortic aneurysms.......The aim of the paper is to compare the epidemiology, risk factors and manifestations of iliac and abdominal aortic aneurysms....

  17. Adult presentation with vascular ring due to double aortic arch.

    Science.gov (United States)

    Kafka, Henryk; Uebing, Anselm; Mohiaddin, Raad

    2006-11-01

    This is a case report on the use of cardiovascular magnetic resonance imaging to diagnose vascular ring due to double aortic arch in an adult presenting with an abnormal chest X-ray. The experience in this case and the literature review identify the benefits of using cardiovascular magnetic resonance imaging to clarify complex aortic arch anatomy.

  18. Double aortic arch and nasogastric tubes: A fatal combination

    Institute of Scientific and Technical Information of China (English)

    Julia Massaad; Kelly Crawford

    2008-01-01

    Double aortic arch is a common form of complete vascular ring that encircles both the trachea and the esophagus, and presents with various respiratory and esophageal symptoms, usually in the pediatric population.We present a case of double aortic arch in an adult patient that manifested as massive upper gastrointestinal bleeding after prolonged nasogastric intubation.

  19. Aortic pulse wave velocity improves cardiovascular event prediction

    DEFF Research Database (Denmark)

    Ben-Shlomo, Yoav; Spears, Melissa; Boustred, Chris;

    2014-01-01

    To determine whether aortic pulse wave velocity (aPWV) improves prediction of cardiovascular (CVD) events beyond conventional risk factors.......To determine whether aortic pulse wave velocity (aPWV) improves prediction of cardiovascular (CVD) events beyond conventional risk factors....

  20. Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves

    DEFF Research Database (Denmark)

    Makkar, Raj R; Fontana, Gregory; Jilaihawi, Hasan;

    2015-01-01

    BACKGROUND: A finding of reduced aortic-valve leaflet motion was noted on computed tomography (CT) in a patient who had a stroke after transcatheter aortic-valve replacement (TAVR) during an ongoing clinical trial. This finding raised a concern about possible subclinical leaflet thrombosis...